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  • Elsevier  (141,934)
  • Oxford University Press  (23,248)
  • MDPI Publishing  (10,327)
  • 2015-2019  (174,669)
  • 1945-1949  (840)
  • 2016  (174,669)
  • 1947  (840)
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  • 1
    Publication Date: 2021-05-12
    Description: Today, satellite remote sensing has reached a key role in Earth Sciences. In particular, Synthetic ApertureRadar (SAR) sensors and SAR Interferometry (InSAR) techniques are widely used for the study of dynamicprocesses occurring inside our living planet. Over the past 3 decades, InSAR has been applied for mappingtopography and deformation at the Earth’s surface. These maps are widely used in tectonics, seismology,geomorphology, and volcanology, in order to investigate the kinematics and dynamics of crustal faulting,the causes of postseismic and interseismic displacements, the dynamics of gravity driven slope failures,and the deformation associated with subsurface movement of water, hydrocarbons or magmatic fluids.
    Description: Published
    Description: 58-82
    Description: 1T. Geodinamica e interno della Terra
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: reserved
    Keywords: SAR ; InSAR ; Earth observation ; Surface displacements ; Satellite missions ; Advanced InSAR ; Earthquake studies ; Volcanic studies ; Tectonic process ; Coseismic studies ; Soil liquefaction ; Post-seismic studies ; Interseismic studies ; Volcanic unrest ; Pre-eruptive phase ; Eruptive phase ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2018-12-19
    Description: The timing and geometry of the initial Gondwana break-up between Africa and East Antarctica is still poorly known due to missing information about the continent-ocean boundaries along the rifted margins. In this context, the Beira High off central Mozambique forms a critical geological feature of uncertain crustal fabric. Based on new wide-angle seismic and potential field data across Beira High a P-wave velocity model, supported by amplitude and gravity modelling, provides constraints on the crustal composition of this area. In the Mozambique Basin mainly normal oceanic crust of 5.5–7 km thickness with velocities of 6.5–7.0 km/s in the lower crust is present. A sharp transition towards Beira High marks the continent-ocean boundary. Here the crust thickens to 23 km at maximum. A small velocity-depth gradient and a constant increase in velocity with basal velocities of maximum 7.0 km/s are in good agreement with typical velocities of continental crust and continental fragments. The density model indicates the existence of felsicmaterial in greater depths and supports a fabric of stretched, but highly intruded continental crust below Beira High. A gradual decrease in crustal thickness characterizes the transition towards the Mozambican shelf area. Here, in the Zambezi Delta Depression 12 km of sediments cover the underlying 7 km thick crust. The presence of a high-velocity lower crustal body with velocities of 7.1–7.4 km/s indicates underplated, magmatic material in this part of the profile. However, the velocity structure in the shelf area allows no definite interpretation because of the experimental setup. Thus, the crustal nature below the Zambezi Delta and consequently the landward position of the continentocean boundary remains unknown. The difference in stretching below the margins of Beira High suggests the presence of different thinning directions and a rift jump during the early rifting stage.
    Repository Name: EPIC Alfred Wegener Institut
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  • 3
    Publication Date: 2016-07-06
    Description: This paper presents the results of measurements of aerosol physical and chemical properties during iAREA2014 campaign that took place on Svalbard between 15th of Mar and 4th of May 2014. With respect to field area, the experiment consisted of two sites: NyeÅlesund (78�550N, 11�560E) and Longyearbyen (78�130N, 15�330E) with further integration of Aerosol Robotic Network (AERONET) station in Hornsund (77�000N, 15�330E). The subject of this study is to investigate the inesitu, passive and active remote sensing observations as well as numerical simulations to describe the temporal variability of aerosol singleescattering properties during spring season on Spitsbergen. The retrieval of the data indicates several event days with enhanced singleescattering properties due to the existence of sulphate and additional seaesalt load in the atmosphere which is possibly caused by relatively high wind speed. Optical results were confirmed by numerical simulations made by the GEMeAQ model and by chemical observations that indicated up to 45% contribution of the seaesalt to a PM10 total aerosol mass concentration. An agreement between the in-situ optical and microphysical properties was found, namely: the positive correlation between aerosol scattering coefficient measured by the nephelometer and effective radius obtained from laser aerosol spectrometer as well as negative correlation between aerosol scattering coefficient and the Ångstrom exponent indicated that slightly larger particles dominated during special events. The inesitu surface observations do not show any significant enhancement of the absorption coefficient as well as the black carbon concentration which might occur during spring. All of extensive singleescattering properties indicate a diurnal cycle in Longyearbyen, where 21:00e5:00 data stays at the background level, however increasing during the day by the factor of 3e4. It is considered to be highly connected with local emissions originating in combustion, traffic and harbour activities. On the other hand, no daily fluctuations in NyeÅlesund are observed. Mean values in NyeÅlesund are equal to 8.2, 0.8 Mm�1 and 103 ng/m3 for scattering, absorption coefficients and black carbon concentration; however in Longyearbyen (only data from 21:00e05:00 UTC) they reach 7.9, 0.6 Mm�1 as well as 83 ng/ m3 respectively. Overall, the spring 2014 was considerably clean and seaesalt was the major aerosol component
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 4
    Publication Date: 2016-09-24
    Description: Thermokarst processes characterize a variety of ice-rich permafrost terrains and often lead to lake formation. The long-term evolution of thermokarst landscapes and the stability and longevity of lakes depend upon climate, vegetation and ground conditions, including the volume of excess ground ice and its distribution. The current lake status of thermokarst-lake landscapes and their future trajectories under climatewarming are better understood in the light of their long-term development. We studied the lake-rich southern marginal upland of the Yukon Flats (northern interior Alaska) using dated lake-sediment cores, observations of river-cut exposures, and remotely-sensed data. The region features thick (up to 40 m)Quaternary deposits (mainly loess) that contain massive ground ice. Two of three studied lakes formed ~11,000–12,000 cal yr BP through inferred thermokarst processes, and fire may have played a role in initiating thermokarst development. From ~9000 cal yr BP, all lakes exhibited steady sedimentation, and pollen stratigraphies are consistentwith regional patterns. The current lake expansion rates are low (0 to b7 cmyr−1 shoreline retreat) compared with other regions (~30 cm yr−1 or more). This thermokarst lake-rich region does not showevidence of extensive landscape lowering by lake drainage, nor of multiple lake generations within a basin. However, LiDAR images reveal linear “corrugations” (N5 m amplitude), deep thermo-erosional gullies, and features resembling lake drainage channels, suggesting that highly dynamic surface processes have previously shaped the landscape. Evidently, widespread early Holocene permafrost degradation and thermokarst lake initiation were followed by lake longevity and landscape stabilization, the latter possibly related to establishment of dense forest cover. Partial or complete drainage of three lakes in 2013 reveals that there is some contemporary landscape dynamism. Holocene landscape evolution in the study area differs from that described from other thermokarst-affected regions; regional responses to future environmental change may be equally individualistic.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
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  • 5
    Publication Date: 2016-09-23
    Description: Thermokarst lakes develop as a result of the thaw and collapse of ice-rich, permanently frozen ground (permafrost). Of particular sedimentological importance are thermokarst lakes forming in late Pleistocene icy silt (yedoma),which dramatically alter the land surface by lowering surface elevation and redistributing upland sediment into lower basins. Our study provides the first description of yedoma thermokarst lake sedimentology based on the crossbasin sampling of an existing lake. We present lake sediment facies descriptions based on data from sediment cores from two thermokarst lakes of medium depth, Claudi and Jaeger (informal names), which formed in previously non thermokarst-affected upland yedoma on the northern Seward Peninsula, Alaska. We identify four prominent facies using sedimentological, biogeochemical, and macrofossil indicators: a massive silt lacking aquatic macrofossils and other aquatic indicators situated below a sub-lacustrine unconformity (Facies 1); two basal deposits: interbedded organic silt and chaotic silt (Facies 2–3); and a silt-rich mud (Facies 4). Facies 1 is interpreted as yedoma that has thawed during lake formation. Facies 3 formed adjacent to the margin due to thaw and collapse events from the lake shore. Material from Facies 3 was reworked by wave action to form Facies 2 in a medium energy margin environment. Facies 4 formed in a lower energy environment toward the lake basin center. This facies classification and description should enhance our ability (i) to interpret the spatial and temporal development of lakes and (ii) to reconstruct long-term patterns of landscape change.
    Repository Name: EPIC Alfred Wegener Institut
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  • 6
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    Elsevier
    In:  EPIC3Fate and Impact of Microplastics in Marine Ecosystems, Fate and Impact of Microplastics in Marine Ecosystems, Elsevier, 1 p., pp. 162-163, ISBN: 978-0-12-812271-6
    Publication Date: 2017-06-21
    Description: Since the 1950s more than 6.1 billion tons of plastics have been produced. It has been estimated that about 10% of this amount will be deposited long-term in theOceans. The problem is highlighted by several currentstudies using different environmental sampling protocols and analytical methods. Effects of this anthropogenic litter on the environment and organisms are heavily on debate, emphasizing the need to transfer this knowledge to young educated people and to fuel educational programs. The school lab OPENSEA at the Alfred-Wegener-Institute on Helgoland started a joint high school project on marine plastic litter in cooperation with the experts of the marine microplastics group at AWI to link science and education more closely. Based on the OSPAR protocol for beach monitoring of marine litter we developed an experimental set up focusing on sampling and identification of plastic litter on beaches, shores and in sediments in the course of the OPENSEA science and education program for grammar and high school scholars. This monitoring provides environmental data on marine plastic litter and will be integrated in a long term data monitoring program in the course of a citizen science study. In addition we plan to integrate also smaller plastic particles into the project. Fractionated sediment samples will be screened for particles 〉 0.5mm, which then will be analyzed by ATR-FT-IR. These educational activities, with a strong link to the latest science and to sophisticated technology will raise the awareness of younger people for the marine litter problematic. We aim at increasingtheir concerns after taking part in this program. We will present background information, sampling strategies, identification efforts and results based on this scholar science project.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 7
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    Elsevier
    In:  EPIC3Fate and Impact of Microplastics in Marine Ecosystems, Elsevier
    Publication Date: 2017-05-29
    Description: The pollution of the oceans with plastic particles smaller than 5 mm, called microplastics is moving into the focus of science and governments. To determine the amount of microplastics several steps are necessary, starting with the sampling, work up and finally analysis. Each step has its own challenges due to small size of the particles. For analysis the imaging with µFTIR microscopy is a powerful tool allowing the analysis of complete filters. Systematic screening for optimal conditions and filter materials have already been performed. This method has a high time demand regarding the measurement and data interpretation. While the measurement is performed mostly by the spectrometer, the interpretation has to be made by hand on the basis of false color images. To overcome the manual part we developed a novel approach based on the Bruker OPUS© Software to decrease the high time demand for the analysis of microplastics. With this approach it was possible to analyze measurement files from focal plane array (FPA) FTIR mapping containing up to 1.8 million single spectra. These spectra were compared with a database of different synthetic and natural polymers by various methods. By benchmark tests their performance was monitored with the focus on accuracy and data quality. After optimization high quality data was generated, which allowed image analysis. Based on these results an approach for image analysis was developed, giving information for the particle size distribution for each polymer type, particle distribution on the filter and polymer distribution for the particles. It was possible to collect all data with relative ease even for complex sample matrices. This approach has significantly decreased the time demand for the interpretation of FTIR-imaging data and increased the generated data quality.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 8
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    Elsevier
    In:  EPIC3Remote Sensing of Environment, Elsevier, 187, pp. 30-48, ISSN: 0034-4257
    Publication Date: 2017-01-20
    Description: Research on processes leading to formation, maintenance, and disappearance of polynyas in the Polar Regions benefits significantly from the use of different types of remote sensing data. The Sentinels of the European Space Agency (ESA), together with other satellite missions, provide a variety of data from different parts of the electromagnetic spectrum, at different spatial scales, and with different temporal resolutions. In a case study we demonstrate the advantage of merging data from different spaceborne instruments for analysing ice conditions and ice dynamics in and around the frequently occurring Terra Nova Bay Polynya (TNBP) in the Ross Sea in the Antarctic. Starting with a list of polynya parameters that are typically retrieved from satellite images, we assess the usefulness of different sensor types. On regional scales (several 100 km), passive microwave radiometers provide a view on the mutual influence of the three Ross Sea polynyas on sea ice drift and deformation patterns. Optical sensors with meter-scale resolution, on the other hand, allow very localized analyses of different polynya zones. The combination of different ranges of the electromagnetic spectrum is essential for recognition and classification of ice types and structures. Radar images together with data from thermal infrared sensors, operated at tens to hundreds of meters resolution, improve the separation of the outlet zone of the polynya from the adjacent pack ice. The direct comparison of radar and passive microwave images reveals the visibility of deformed ice zone in the latter. A sequence of radar images was employed to retrieve ice drift around the TNB, which allows analysing the temporal changes of the polynya area and the extension and structure of the outlet zone as well as ice movements and deformation that are influenced by the katabatic winds.
    Repository Name: EPIC Alfred Wegener Institut
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  • 9
    Publication Date: 2016-10-10
    Repository Name: EPIC Alfred Wegener Institut
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  • 10
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    Elsevier
    In:  EPIC3Climate Change, Ocean Current Changes, Amsterdam, Elsevier, pp. 253-269
    Publication Date: 2016-12-05
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 11
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    Elsevier
    In:  EPIC3Deep Sea Research Part I: Oceanographic Research Papers, Elsevier, 107, pp. 70-81
    Publication Date: 2019-08-19
    Description: The Weddell Sea plays an important role for the global oceans and climate by being one of the biggest production and export areas of Antarctic Bottom Water (AABW). Circumpolar Deep Water (CDW) enters the Weddell Gyre (WG) at its eastern boundary. Then called Warm Deep Water (WDW), it is a major contributor to the formation of deep and bottom waters due to ocean-ice shelf interactions in the southern and soutwestern Weddell Sea. Hydrographic data collected between 0 and 30°E on the RV Polarstern cruise ANT XX/2 reveals a two-core structure for the eastern inflow of warm water at roughly 20°E but not further downstream at the Greenwich meridian (GM). Model results and climatological fields suggest that the two cores represent two separate modes of warm inflow. One mode is driven by eddy mixing in the northeastern corner of the WG and the other one is an advective mode, forming the southern branch of the inflow which extends beyond 30°E before turning westward. Both pathways are likely to carry waters from different origins within the Antarctic Circumpolar Current (ACC), where more ventilated CDW is found at the Southern Boundary (SB) compared to the centre. The southern route shows considerable interannual variability in the model. A variable inflow of two types of CDW together with admixed recirculated and cooler waters from the Weddell Sea can potentially contribute to the observed variability and warming trend of WDW over the last decade at the GM.
    Repository Name: EPIC Alfred Wegener Institut
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  • 12
    Publication Date: 2019-07-17
    Description: Microcystis are known for their potential ability to synthesize toxins, mainly microcystins (MCs). In order to evaluate the effects of temperature on chlorophyll a (Chl a), growth, physiological responses and toxin production of a native Microcystis aeruginosa, we exposed the cells to low (23 °C) and high (29 °C) temperature in addition to a 26 °C control treatment. Exponential growth rate was significantly higher at 29 °C compared to 23 °C and control, reaching 0.43, 0.32 and 0.33 day−1 respectively. In addition, there was a delay of the start of exponential growth at 23 °C. However, the intracellular concentration of Chl a decreased significantly due to temperature change. A significant increase in intracellular ROS was observed in coincidence with the activation of enzymatic antioxidant catalase (CAT) during the first two days of exposure to 23° and 29 °C in comparison to the control experiment, decreasing thereafter to nearly initial values. Five MCs were determined by LC-MS/MS analysis. In the experiments, the highest MC concentration, 205 fg [Leu1] MC-LR.cell− 1 expressed as MC-LR equivalent was measured in the beginning of the experiment and subsequently declined to 160 fg.cell− 1 on day 2 and 70 fg.cell− 1 on day 4 in cells exposed to 29 °C. The same trend was observed for all other MCs except for the least abundant MC-LR which showed a continuous increase during exposure time. Our results suggest a high ability of M. aeruginosa to perceive ROS and to rapidly initiate antioxidant defenses with a differential response on MC production.
    Repository Name: EPIC Alfred Wegener Institut
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  • 13
    Publication Date: 2016-10-01
    Repository Name: EPIC Alfred Wegener Institut
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  • 14
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    Elsevier
    In:  EPIC3MICRO 2016. Fate and Impact of Microplastics in Marine Ecosystems, MICRO 2016. Fate and Impact of Microplastics in Marine Ecosystems, Elsevier, 1 p., pp. 120-120, ISBN: 9780128122716
    Publication Date: 2016-12-12
    Repository Name: EPIC Alfred Wegener Institut
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  • 15
    Publication Date: 2017-06-07
    Description: Over the past ~ 5000 years, amplified dust generation and deposition in the American West has been linked to human activity. In recent decades, intensified rates of agriculture and livestock grazing have been correlated with greater dust production detected on seasonal to annual timescales. The combination of land use intensification and climate change (i.e. increased drought frequency) in North America highlights the importance of characterizing the sources of dust both before and after the influence of anthropogenic activity. We apply high-precision geochemical and isotopic (Sr and Nd isotopes) techniques to an ice core from the Upper Fremont Glacier (Wyoming, USA) to produce the first glacial dataset from the American West. Our Sr-Nd isotopic composition data indicates the evolving dust provenance to the Upper Fremont Glacier (UFG) from a long-range transport of mineral dust to a local source. This increasing input of dust from a local source is supported by a rise in average dust particle diameter combined with greater average dust concentration throughout the record. The greater presence of dust particles smaller than 2.5 μm in the most recent samples from UFG ice core record support existing satellite and sediment core data regarding the effects of anthropogenic activity upon dust sources and pathways in the American West. Although the Sr-Nd isotope database in North America needs be expanded, our results provide a survey of windborne dust through the past 270 years.
    Repository Name: EPIC Alfred Wegener Institut
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  • 16
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    Oxford University Press
    Publication Date: 2017-04-04
    Description: We provide an updated present-day stress map for the Italian territory. Following the World Stress Map (WSM) Project guidelines, we list the different stress indicators, explaining the criteria used to select data. We discuss the data, which will also be included in the 2016 release of the WSM, highlighting the areas for which we have added stress information. Our map displays the minimum horizontal stress orientations inferred from crustal stress indicators down to 40 km depth using data of A–C quality, updated for earthquakes until December 2015. We have completely reviewed all data, and the data set now contains 855 entries, in contrast to the previous 715. The number of data with A–C quality of 630 corresponds to an increase of 26 per cent relative to the previous data set. In particular, the new data set contains the results of the analysis of borehole breakouts, critically reviewed data from earthquake focal mechanisms, data concerning active faults, formal inversions of focal mechanisms of seismic sequences or of restricted areas and one stress determination from overcoring. The new data set defines the stress field in areas not well covered by the previous data: the region north to the Po Plain and the central Adriatic sea, both characterized by a thrust- and strike-faulting regime, the northern Sicilian belt with a prevailing normal-faulting regime, and the Ionian sea with a strike-slip regime.
    Description: Published
    Description: 1525-1531
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Seismicity and tectonics ; Dynamics: seismotectonics ; Crustal structure ; Europe ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2017-04-04
    Description: Although there are many methods for investigating tectonic structures, many faults remain hidden, and they can endanger the life and property of people living along them. The slopes of volcanoes are covered with such hidden faults, near which strong earthquakes and gas releases can appear. Revealing hidden faults can therefore contribute significantly to the protection of people living in volcanic areas. In the study, seven different techniques were used for making measurements of in-soil radon concentrations in order to search for hidden faults on the SE flank of the Mt. Etna volcano. These reported methods had previously been proved to be useful tools for investigating fault structures. The main aim of the experiment presented here was to evaluate the usability of these methods in the geological conditions of the Mt. Etna region, and to find the best place for continual radon monitoring using a permanent station in the near future.
    Description: Published
    Description: 70-73
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Mt. Etna ; soil gas ; hidden faults ; radon ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2019-07-17
    Description: Reactive iron (oxyhydr)oxide minerals preferentially undergo early diagenetic redox cycling which can result in the production of dissolved Fe(II), the adsorption of Fe(II) onto particle surfaces, and the formation of authigenic Fe minerals. The partitioning of iron in sediments has traditionally been studied by applying sequential extractions that target operationally-defined iron phases. Here, we complement an existing sequential leaching method by developing a sample processing protocol for δ56Fe analysis, which we subsequently use to study Fe phase-specific fractionation related to dissimilatory iron reduction in a modern marine sediment. Carbonate-Fe was extracted by acetate, easily reducible oxides (e.g. ferrihydrite and lepidocrocite) by hydroxylamine–HCl, reducible oxides (e.g. goethite and hematite) by dithionite–citrate, and magnetite by ammonium oxalate. Subsequently, the samples were repeatedly oxidized, heated and purified via Fe precipitation and column chromatography. The method was applied to surface sediments collected from the North Sea, south of the island of Helgoland. The acetate-soluble fraction (targeting siderite and ankerite) showed a pronounced downcore δ56Fe trend. This iron pool was most depleted in 56Fe close to the sediment–water interface, similar to trends observed for pore-water Fe(II). We interpret this pool as surface-reduced Fe(II), rather than siderite or ankerite, that was open to electron and atom exchange with the oxide surface. Common extractions using 0.5 M HCl or Na-dithionite alone may not resolve such trends, as they dissolve iron from isotopically distinct pools leading to a mixed signal. Na-dithionite leaching alone, for example, targets the sum of reducible Fe oxides that potentially differ in their isotopic fingerprint. Hence, the development of a sequential extraction Fe isotope protocol provides a new opportunity for detailed study of the behavior of iron in a wide range of environmental settings.
    Repository Name: EPIC Alfred Wegener Institut
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  • 19
    Publication Date: 2016-02-12
    Description: The focus of this research has been on detecting changes in lake areas, vegetation, land surface temperatures, and the area covered by snow, using data from remote sensing. The study area covers the main (central) part of the Lena River catchment in the Yakutia region of Siberia (Russia), extending from east of Yakutsk to the central Siberian Plateau, and from the southern Lena River to north of the Vilyui River. Approximately 90% of the area is underlain by continuous permafrost. Remote sensing products were used to analyze changes in water bodies, land surface temperature (LST), and leaf area index (LAI), as well as the occurrence and extent of forest fires, and the area and duration of snow cover. The remote sensing analyses (for LST, snow cover, LAI, and fire) were based on MODIS–derived NASA products (250–1000 m) for 2000 to 2011. Changes in water bodies were calculated from two mosaics of (USGS) Landsat (30 m) satellite images from 2002 and 2009. Within the study area's 315,000 km2 the total area covered by lakes increased by 17.9% between 2002 and 2009, but this increase varied in different parts of the study area, ranging between 11% and 42%. The land surface temperatures showed a consistent warming trend, with an average increase of about 0.12 °C/year. The average rate of warming during the April–May transition period was 0.17 °C/year and 0.19 °C/year in the September–October period, but ranged up to 0.49 °C/year during September–October. Regional differences in the rates of land surface temperature change, and possible reasons for the temperature changes, are discussed with respect to changes in the land cover. Our analysis of a broad spectrum of variables over the study area suggests that the spring warming trend is very likely to be due to changes in the area covered by snow. The warming trend observed in fall does not, however, appear to be directly related to any changes in the area of snow cover, or to the atmospheric conditions, or to the proportion of the land surface that is covered by water (i.e., to wetting and drying). Supplementary data (original data, digitized version of the maps, metadata) are archived under PANGAEA (http://dx.doi.org/10.1594/PANGAEA.855124).
    Repository Name: EPIC Alfred Wegener Institut
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  • 20
    Publication Date: 2016-06-23
    Description: The Southern Ocean (SO) is a major sink for anthropogenic atmospheric carbon dioxide (CO2), potentially harbouring even greater potential for additional sequestration of CO2 through enhanced phytoplankton productivity. In the SO, primary productivity is primarily driven by bottom up processes (physical and chemical conditions) which are spatially and temporally heterogeneous. Due to a paucity of trace metals (such as iron) and high variability in light, much of the SO is characterised by an ecological paradox of high macronutrient concentrations yet uncharacteristically low chlorophyll concentrations. It is expected that with increased anthropogenic CO2 emissions and the coincident warming, the major physical and chemical process that govern the SO will alter, influencing the biological capacity and functioning of the ecosystem. This review focuses on the SO primary producers and the bottom up processes that underpin their health and productivity. It looks at the major physico-chemical drivers of change in the SO, and based on current physiological knowledge, explores how these changes will likely manifest in phytoplankton, specifically, what are the physiological changes and floristic shifts that are likely to ensue and how this may translate into changes in the carbon sink capacity, net primary productivity and functionality of the SO.
    Repository Name: EPIC Alfred Wegener Institut
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  • 21
    Publication Date: 2017-06-14
    Description: We compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal. In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal regions, with the upward mixing of iron, maintain greatly enhanced rates of production, especially in coastal polynyas. In these coastal areas, elevated primary production supports large biomasses of zooplankton, fish, seabirds, and mammals. As climate warming affects these advective processes and their heat content, there will likely be major changes in the distribution and abundance of polar biota, in particular the biota dependent on sea ice.
    Repository Name: EPIC Alfred Wegener Institut
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  • 22
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    Oxford University Press
    In:  EPIC3ICES Journal of Marine Science, Oxford University Press, 73, pp. 772-782, ISSN: 1054-3139
    Publication Date: 2016-11-30
    Description: Global warming and ocean acidification are among the most important stressors for aquatic ecosystems in the future. To investigate their direct and indirect effects on a near-natural plankton community, a multiple-stressor approach is needed. Hence, we set up mesocosms in a full-factorial design to study the effects of both warming and high CO2 on a Baltic Sea autumn plankton community, concentrating on the impacts on microzooplankton (MZP). MZP abundance, biomass, and species composition were analysed over the course of the experiment. We observed that warming led to a reduced time-lag between the phytoplankton bloom and an MZP biomass maximum. MZP showed a significantly higher growth rate and an earlier biomass peak in the warm treatments while the biomass maximum was not affected. Increased pCO2 did not result in any significant effects on MZP biomass, growth rate, or species composition irrespective of the temperature, nor did we observe any significant interactions between CO2 and temperature. We attribute this to the high tolerance of this estuarine plankton community to fluctuations in pCO2, often resulting in CO2 concentrations higher than the predicted end-of-century concentration for open oceans. In contrast, warming can be expected to directly affect MZP and strengthen its coupling with phytoplankton by enhancing its grazing pressure.
    Repository Name: EPIC Alfred Wegener Institut
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  • 23
    Publication Date: 2016-03-17
    Description: Forests worldwide are threatened by various environmental and anthropogenic hazards, especially tropical forests. Knowledge on the impacts of these hazards on forest structure and dynamics has been compiled in empirical studies. However, the results of these studies are often not sufficient for long-term projections and extrapolations to large spatial scales especially for unprecedented environmental conditions, which require both the identification and understanding of key underlying processes. Forest models bridge this gap by incorporating multiple ecological processes in a dynamic framework (i.e. including a realistic model structure) and addressing the complexity of forest ecosystems. Here, we describe the evolution of the individual-based and process-based forest gap model FORMIND and its application to tropical forests. At its core, the model includes physiological processes on tree level (photosynthesis, respiration, tree growth, mortality, regeneration, competition). During the past two decades, FORMIND has been used to address various scientific questions arising from different forest types by continuously extending the model structure. The model applications thus provided understanding in three main aspects: (1) the grouping of single tree species into plant functional types is a successful approach to reduce complexity in vegetation models, (2) structural realism was necessary to analyze impacts of natural and anthropogenic disturbances such as logging, fragmentation, or drought, and (3) complex ecological processes such as carbon fluxes in tropical forests – starting from the individual tree level up to the entire forest ecosystem – can be explored as a function of forest structure, species composition and disturbance regime. Overall, this review shows how the evolution of long-term modelling projects not only provides scientific understanding of forest ecosystems, but also provides benefits for ecological theory and empirical study design.
    Repository Name: EPIC Alfred Wegener Institut
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  • 24
    Publication Date: 2016-05-02
    Description: Recent declines in ice shelf and sea ice extent experienced in polar regions highlight the importance of evaluating variations in local weather patterns in response to climate change. Airborne mineral particles (dust) transported through the atmosphere and deposited on ice sheets and glaciers in Antarctica and Greenland can provide a robust set of tools for resolving the evolution of climatic systems through time. Here we present the first high time resolution radiogenic isotope (strontium and neodymium) data for Holocene dust in a coastal East Antarctic ice core, accompanied by rare earth element composition, dust concentration, and particle size distribution during the last deglaciation. We aim to use these combined ice core data to determine dust provenance, with variations indicative of shifts in either dust production, sources, and/or transport pathways. We analyzed a series of 17 samples from the Taylor Dome (77◦47'47''S, 158◦43'26''E) ice core, 113–391m in depth from 1.1–31.4ka. Radiogenic isotopic and rare earth element compositions of dust during the last glacial period are in good agreement with previously measured East Antarctic ice core dust records. In contrast, the Holocene dust dataset displays a broad range in isotopic and rare earth element compositions, suggesting a shift from long-range transported dust to a more variable, local input that may be linked to the retreat of the Ross Ice Shelf during the last deglaciation. Observed changes in the dust cycle inferred from a coastal East Antarctic ice core can thus be used to infer an evolving local climate.
    Repository Name: EPIC Alfred Wegener Institut
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  • 25
    Publication Date: 2022-05-25
    Description: Author Posting. © Crown Copyright, 2015. This article is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 204 (2016): 1-20, doi:10.1093/gji/ggv416.
    Description: The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with borehole data for Miocene turbidites in the eastern Gulf of Mexico. The station-specific results also indicate that Quaternary sediments coarsen towards the Beaufort-Mackenzie and Banks Island margins in a manner that is consistent with the variable history of Laurentide Ice Sheet advance documented for these margins. Lithological factors do not fully account for the elevated velocity–depth trends that are associated with the southwestern Canada Basin and the Alpha-Mendeleev magnetic domain. Accelerated porosity reduction due to elevated palaeo-heat flow is inferred for these regions, which may be related to the underlying crustal types or possibly volcanic intrusion of the sedimentary succession. Beyond exploring the variation of an important physical property in the Arctic Ocean basin, this study provides comparative reference for global studies of seismic velocity, burial history, sedimentary compaction, seismic inversion and overpressure prediction, particularly in mudrock-dominated successions.
    Keywords: Numerical approximations and analysis ; Spatial analysis ; Controlled source seismology ; Acoustic properties ; Sedimentary basin processes ; Large igneous provinces ; Crustal structure ; Arctic region
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  • 26
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Continental Shelf Research 124 (2016): 165-181, doi:10.1016/j.csr.2016.06.005.
    Description: A new hydrographic climatology has been created for the continental shelf region, extending from the Labrador shelf to the Mid-Atlantic Bight. The 0.2-degree climatology combines all available observations of surface and bottom temperature and salinity collected between 1950 and 2010 along with the location, depth and date of these measurements. While climatological studies of surface and bottom temperature and salinity have been presented previously for various regions along the Canadian and U.S. shelves, studies also suggest that all these regions are part of one coherent system. This study focuses on the coherent structure of the mean seasonal cycle of surface and bottom temperature and salinity and its variation along the shelf and upper slope. The seasonal cycle of surface temperature is mainly driven by the surface heat flux and exhibits strong dependency on latitude (r≈−0.9). The amplitude of the seasonal cycle of bottom temperature is rather dependent on the depth, while the spatial distribution of bottom temperature is correlated with latitude. The seasonal cycle of surface salinity is influenced by several components, such as sea-ice on the northern shelves and river discharge in the Gulf of St. Lawrence. The bottom salinity exhibits no clear seasonal cycle, but its spatial distribution is highly correlated with bathymetry, thus Slope Water and its intrusion on the shelf can be identified by its relatively high salinity compared to shallow, fresher shelf water. Two different regimes can be identified, especially on the shelf, separated by the Laurentian Channel: advection influences the phasing of the seasonal cycle of surface salinity and bottom temperature to the north, while in the southern region, river runoff and air-sea heat flux forcing are dominant, especially over the shallower bathymetry.
    Description: Support from NSF OCE PO to Y-OK (OCE-1242989 and OCE-1435602) and SJL (OCE-1332666).
    Keywords: Seasonal climatology ; Temperature ; Salinity ; Dataset ; Shelf
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  • 27
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Genome Biology and Evolution 7 (2015): 3207-3225, doi:10.1093/gbe/evv210.
    Description: High-throughput sequencing of reduced representation libraries obtained through digestion with restriction enzymes—generically known as restriction site associated DNA sequencing (RAD-seq)—is a common strategy to generate genome-wide genotypic and sequence data from eukaryotes. A critical design element of any RAD-seq study is knowledge of the approximate number of genetic markers that can be obtained for a taxon using different restriction enzymes, as this number determines the scope of a project, and ultimately defines its success. This number can only be directly determined if a reference genome sequence is available, or it can be estimated if the genome size and restriction recognition sequence probabilities are known. However, both scenarios are uncommon for nonmodel species. Here, we performed systematic in silico surveys of recognition sequences, for diverse and commonly used type II restriction enzymes across the eukaryotic tree of life. Our observations reveal that recognition sequence frequencies for a given restriction enzyme are strikingly variable among broad eukaryotic taxonomic groups, being largely determined by phylogenetic relatedness. We demonstrate that genome sizes can be predicted from cleavage frequency data obtained with restriction enzymes targeting “neutral” elements. Models based on genomic compositions are also effective tools to accurately calculate probabilities of recognition sequences across taxa, and can be applied to species for which reduced representation data are available (including transcriptomes and neutral RAD-seq data sets). The analytical pipeline developed in this study, PredRAD (https://github.com/phrh/PredRAD), and the resulting databases constitute valuable resources that will help guide the design of any study using RAD-seq or related methods.
    Description: This research was supported by the Office of Ocean Exploration and Research of the National Oceanic and Atmospheric Administration (NA09OAR4320129 to T.S.); the Division of Ocean Sciences of the National Science Foundation (OCE-1131620 to T.S.); the Astrobiology Science and Technology for Exploring Planets program of the National Aeronautics and Space Administration (NNX09AB76G to T.S.); and the Academic Programs Office (Ocean Ventures Fund to S.H.), the Ocean Exploration Institute (Fellowship support to T.M.S.), and the Ocean Life Institute of the Woods Hole Oceanographic Institution (internal grant to T.M.S. and S.H.).
    Keywords: RAD-seq ; Reduced representation sequencing ; PredRAD ; Experimental design ; Genome size prediction ; Restriction recognition sequence probability
    Repository Name: Woods Hole Open Access Server
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  • 28
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Quaternary Geochronology 30 (2015): 114–131, doi:10.1016/j.quageo.2015.09.001.
    Description: The ages of recent effusive eruptions on Erebus volcano, Antarctica are poorly known. Published 40Ar/39Ar ages of the 10 youngest “post-caldera” lava flows are unreliable because of the young ages of the flows (〈10 ka) and the presence of excess 40Ar. Here we use cosmogenic 3He and 36Cl to provide new ages for the 10 youngest flows and 3 older summit flows, including a newly recognized flow distinguished by its exposure age. Estimated eruption ages of the post-caldera flows, assuming no erosion or prior snow cover, range from 4.52 ± 0.08 ka to 8.50 ± 0.19 ka, using Lifton et al. (2014) to scale cosmogenic production rates. If the older Lal (1991)/Stone (2000) model is used to scale production rates, calculated ages are older by 16–25%. Helium-3 and chlorine-36 exposure ages measured on the same samples show excellent agreement. Helium-3 ages measured on clinopyroxene and olivine from the same samples are discordant, probably due in part to lower-than-expected 3He production rates in the Fe-rich olivine. Close agreement of multiple clinopyroxene 3He ages from each flow indicates that the effects of past snow coverage on the exposure ages have been minimal. The new cosmogenic ages differ considerably from published 40Ar/39Ar and 36Cl ages and reveal that the post-caldera flows were erupted during relatively brief periods of effusive activity spread over an interval of ∼4 ka. The average eruption rate over this interval is estimated to be 0.01 km3/ka. Because the last eruption was at least 4 ka ago, and the longest repose interval between the 10 youngest eruptions is ∼1 ka, we consider the most recent period of effusive activity to have ended.
    Description: This research was supported by grant ANT-1142083 from the National Science Foundation, Division of Polar Programs.
    Keywords: Erebus volcano ; Cosmogenic nuclides ; Exposure age ; Helium-3 ; Chlorine-36
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  • 29
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 132 (2016): 263–264, doi:10.1016/j.dsr2.2016.08.001.
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  • 30
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Methods in Oceanography 17 (2016): 264-281, doi:10.1016/j.mio.2016.09.004.
    Description: Understanding intrusive exchange at oceanic water mass fronts may depend on building data-constrained models of the processes, but obtaining the needed representative and comprehensive data is challenging. Acoustic imaging (remote sensing) is an attractive method for mapping the three-dimensional intrusion geometry to enable the required focused in situ sampling of the mixing processes in intrusions. The method depends on backscatter of sound from sharp interfaces and from microstructure resulting from double-diffusive instability (DDI), a probable occurrence at intrusions. The potential of the method is evaluated using data collected using established methods in a field of intrusions south of New England. Above and beneath warm and salty intrusions may lie diffusive–convective DDI microstructure and salt-fingering microstructure, respectively, marking the intrusion boundaries, providing the backscattering features. The data show that both types of microstructure can occur in close proximity within intrusions, but the question of whether this is common or not is unanswered by the modest amount of data, as are questions about continuity of DDI-microstructure in intrusions (to facilitate intrusion acoustic imaging) and variability of DDI-driven heat, salt and buoyancy fluxes. Analysis here shows that detectable backscatter from DDI-microstructure will occur, and can be easily measured when plankton scattering is low enough. Interface scattering is also likely to be detectable. The DDI-linked microstructure data used here are inherently interesting in their own right and are presented in some detail.
    Description: The data were collected under Office of Naval Research grant N00014-03-1-0335. Acoustic analysis was done under grant N00014-14-1-0223/N00014-16-1-2372.
    Keywords: Intrusions ; Double-diffusive microstructure ; Ocean mixing ; Acoustic backscatter ; Echosounder ; South New England shelf
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  • 31
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Palaeogeography, Palaeoclimatology, Palaeoecology 451 (2016): 73-83, doi:10.1016/j.palaeo.2016.03.018.
    Description: Sea-level records from atolls, potentially spanning the Cenozoic, have been largely overlooked, in part because the processes that control atoll form (reef accretion, carbonate dissolution, sediment transport, vertical motion) are complex and, for many islands, unconstrained on million-year timescales. Here we combine existing observations of atoll morphology and corelog stratigraphy from Enewetak Atoll with a numerical model to (1) constrain the relative rates of subsidence, dissolution and sedimentation that have shaped modern Pacific atolls and (2) construct a record of sea level over the past 8.5 million years. Both the stratigraphy from Enewetak Atoll (constrained by a subsidence rate of ~ 20 m/Myr) and our numerical modeling results suggest that low sea levels (50–125 m below present), and presumably bi-polar glaciations, occurred throughout much of the late Miocene, preceding the warmer climate of the Pliocene, when sea level was higher than present. Carbonate dissolution through the subsequent sea-level fall that accompanied the onset of large glacial cycles in the late Pliocene, along with rapid highstand constructional reef growth, likely drove development of the rimmed atoll morphology we see today.
    Description: Support for this work was provided through a Jackson School Distinguished Postdoctoral Fellowship to Michael Toomey.
    Keywords: Reef ; Coral ; Dissolution ; Late Miocene ; Oxygen isotope stack
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  • 32
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Neurobiology of Aging 47 (2016): 113–126, doi:10.1016/j.neurobiolaging.2016.07.015.
    Description: Misfolded tau proteins are characteristic of tauopathies, but the isoform composition of tau inclusions varies by tauopathy. Using aggregates of the longest tau isoform (containing 4 microtubule-binding repeats and 4-repeat tau), we recently described a direct mechanism of toxicity that involves exposure of the N-terminal phosphatase-activating domain (PAD) in tau, which triggers a signaling pathway that disrupts axonal transport. However, the impact of aggregation on PAD exposure for other tau isoforms was unexplored. Here, results from immunochemical assays indicate that aggregation-induced increases in PAD exposure and oligomerization are common features among all tau isoforms. The extent of PAD exposure and oligomerization was larger for tau aggregates composed of 4-repeat isoforms compared with those made of 3-repeat isoforms. Most important, aggregates of all isoforms exhibited enough PAD exposure to significantly impair axonal transport in the squid axoplasm. We also show that PAD exposure and oligomerization represent common pathological characteristics in multiple tauopathies. Collectively, these results suggest a mechanism of toxicity common to each tau isoform that likely contributes to degeneration in different tauopathies.
    Description: This work was supported by NIH grants R01 AG044372 (Nicholas M. Kanaan), R01 NS082730 (Nicholas M. Kanaan and Scott T. Brady), BrightFocus Foundation (A2013364S, Nicholas M. Kanaan), the Jean P. Schultz Biomedical Research Endowment (Nicholas M. Kanaan), the Secchia Family Foundation (Nicholas M. Kanaan) and NS066942A (Gerardo Morfini).
    Keywords: Tauopathy ; Alzheimer's disease ; Oligomer ; Axon ; Aggregation ; Microtubule-associated protein ; Pathological conformations
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  • 33
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nucleic Acids Research 44 (2016): e157, doi:10.1093/nar/gkw738.
    Description: Site-directed RNA editing (SDRE) is a strategy to precisely alter genetic information within mRNAs. By linking the catalytic domain of the RNA editing enzyme ADAR to an antisense guide RNA, specific adenosines can be converted to inosines, biological mimics for guanosine. Previously, we showed that a genetically encoded iteration of SDRE could target adenosines expressed in human cells, but not efficiently. Here we developed a reporter assay to quantify editing, and used it to improve our strategy. By enhancing the linkage between ADAR's catalytic domain and the guide RNA, and by introducing a mutation in the catalytic domain, the efficiency of converting a UAG premature termination codon (PTC) to tryptophan (UGG) was improved from ∼11% to ∼70%. Other PTCs were edited, but less efficiently. Numerous off-target edits were identified in the targeted mRNA, but not in randomly selected endogenous messages. Off-target edits could be eliminated by reducing the amount of guide RNA with a reduction in on-target editing. The catalytic rate of SDRE was compared with those for human ADARs on various substrates and found to be within an order of magnitude of most. These data underscore the promise of site-directed RNA editing as a therapeutic or experimental tool.
    Description: National Institutes of Health [1R0111223855, 1R01NS64259]; Cystic Fibrosis Foundation Therapeutics [Rosent14XXO]; Infrastructural support was provided by the National Institutes of Health [NIGMS 1P20GM103642, NIMHD 8G12-MD007600]; National Science Foundation [DBI 0115825, DBI 1337284]; Department of Defense [52680-RT-ISP].
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  • 34
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Chemistry 177 (2015): 366–373, doi:10.1016/j.marchem.2015.06.012.
    Description: Metabolomics is the study of small molecules, or ‘metabolites’, that are the end products of biological processes. While -omics technologies such as genomics, transcriptomics, and proteomics measure the metabolic potential of organisms, metabolomics provides detailed information on the organic compounds produced during metabolism and found within cells and in the environment. Improvements in analytical techniques have expanded our understanding of metabolomics and developments in computational tools have made metabolomics data accessible to a broad segment of the scientific community. Yet, metabolomics methods have only been applied to a limited number of projects in the marine environment. Here, we review analysis techniques for mass spectrometry data and summarize the current state of metabolomics databases. We then describe a boutique database developed in our laboratory for efficient data analysis and selection of mass spectral targets for metabolite identification. The code to implement the database is freely available on GitHub (https://github.com/joefutrelle/domdb). Data organization and analysis are critical, but often under-appreciated, components of metabolomics research. Future advances in environmental metabolomics will take advantage of continued development of new tools that facilitate analysis of large metabolomics datasets.
    Description: The field data populating the database comes from scientific cruises funded by grants from the National Science Foundation to EBK and KL (Atlantic Ocean, OCE-1154320) and E.V. Armbrust (Pacific Ocean, OCE-1205233). The laboratory experiment with coastal seawater was funded by a grant from the Gulf of Mexico Research Initiative to EBK and H.K. White. The laboratory experiments with microbial isolates and the database development are funded by the Gordon and Betty Moore Foundation through Grant GBMF3304 to EBK.
    Keywords: Metabolomics ; Data analysis ; Database design
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  • 35
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 381 (2016): 42–53, doi:10.1016/j.margeo.2016.08.008.
    Description: Behavior of coastal systems on time scales ranging from single storm events to years and decades is controlled by both small-scale sediment transport processes and large-scale geologic, oceanographic, and morphologic processes. Improved understanding of coastal behavior at multiple time scales is required for refining models that predict potential erosion hazards and for coastal management planning and decision-making. Here we investigate the primary controls on shoreline response along a geologically-variable barrier island on time scales resolving extreme storms and decadal variations over a period of nearly one century. An empirical orthogonal function analysis is applied to a time series of shoreline positions at Fire Island, NY to identify patterns of shoreline variance along the length of the island. We establish that there are separable patterns of shoreline behavior that represent response to oceanographic forcing as well as patterns that are not explained by this forcing. The dominant shoreline behavior occurs over large length scales in the form of alternating episodes of shoreline retreat and advance, presumably in response to storms cycles. Two secondary responses include long-term response that is correlated to known geologic variations of the island and the other reflects geomorphic patterns with medium length scale. Our study also includes the response to Hurricane Sandy and a period of post-storm recovery. It was expected that the impacts from Hurricane Sandy would disrupt long-term trends and spatial patterns. We found that the response to Sandy at Fire Island is not notable or distinguishable from several other large storms of the prior decade.
    Description: Funding for this research was provided by the USGS Coastal and Marine Geology Program and the USGS Natural Resource Preservation Program.
    Keywords: Shoreline change ; Coastal evolution ; Storm response ; Empirical orthogonal function ; Fire Island
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  • 36
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 380 (2016): 284–289, doi:10.1016/j.margeo.2016.04.008.
    Description: Rivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion.
    Description: This project was supported by a Jackson School Distinguished Postdoctoral Fellowship to Michael Toomey and the WHOI Coastal Ocean Institute and Ocean and Climate Change Institute.
    Keywords: Coral ; Island ; Lagoon ; Dissolution ; Morphology
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  • 37
    Publication Date: 2016-09-23
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 179 (2016): 123-141, doi:10.1016/j.gca.2016.01.023.
    Description: The carbonate clumped isotope thermometer is a promising tool for determining past ocean temperatures. It is based on the temperature dependence of rare isotopes ‘clumping’ into the same carbonate ion group in the carbonate mineral lattice. The extent of this clumping effect is independent of the isotope composition of the water from which carbonate precipitates, providing unique advantages over many other paleotemperature proxies. Existing calibrations of this thermometer in cold-water and warm-water corals suggest clumped isotope ‘vital effects’ are negligible in cold-water corals but may be significant in warm-water corals. Here, we test the calibration of the carbonate clumped isotope thermometer in cold-water corals with a recently collected and well characterised sample set spanning a range of coral genera (Balanophyllia, Caryophyllia, Dasmosmilia, Desmophyllum, Enallopsammia and Javania). The clumped isotope compositions (Δ47) of these corals exhibit systematic dependences on their growth temperatures, confirming the basis of the carbonate clumped isotope thermometer. However, some cold-water coral genera show Δ47 values that are higher than the expected equilibrium values by up to 0.05‰ (equivalent to underestimating temperature by ∼9 °C) similar to previous findings for some warm-water corals. This finding suggests that the vital effects affecting corals Δ47 are common to both warm- and cold-water corals. By comparison with models of the coral calcification process we suggest that the clumped isotope offsets in these genera are related to the kinetic isotope effects associated with CO2 hydration/hydroxylation reactions in the corals’ calcifying fluid. Our findings complicate the use of the carbonate clumped isotope thermometer in corals, but suggest that species- or genus-specific calibrations could be useful for the future application of this paleotemperature proxy.
    Description: This work was supported by a British National Environment Research Council studentship to P. Spooner (NE/K500823/1), National Science Foundation Grant NSF-ANT-1246387 and The Penzance Endowed Fund in Support of Assistant Scientists (WHOI) to W. Guo, and by funds from the European Research Council, the Leverhulme Trust and a Marie Curie Reintegration grant.
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  • 38
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    Elsevier
    In:  EPIC3Global and Planetary Change, Elsevier, 146, pp. 10-21, ISSN: 09218181
    Publication Date: 2021-08-20
    Description: The impact of observed changes in air temperature and precipitation from 1969 to 2013 and climate projections for 2050 and 2080 at Ny-Ålesund, an arctic research station on Spitzbergen Island in the Svalbard Archipelago on snow hydrological processes, were analyzed using snow accumulation and ablation algorithms in the physically based Cold Regions HydrologicalModelling platform(CRHM). The climate projectionswere obtained from phase 5 of the Coupled Model Intercomparison Project (CMIP5), with a focus on the snow-dominated period (October to June). To identify the potential effects of increasing temperature and precipitation, a model sensitivity analysis (1 °C to 5 °C), with and without a 25% increase in precipitation, was run on CRHM snow processes. The results indicated that the greatest observed warming was during the early snow season (October–February), with increases of 0.8 and 0.9 °C decade−1 for maximum (Tmax) and minimum (Tmin) temperatures, respectively. Therewas also a significant increase in annual and winter precipitation (24mmdecade−1). The late snowseason (March–June) also had a marked increase in temperature (0.5 and 0.69 °C decade−1 for Tmax and Tmin respectively), but no significant change in precipitation. These changes lead to a significant increase in the number of dayswith rainfall rather than snowfall. The sensitivity analysis indicated that mean snowwater equivalent snowpack will decrease by 10.2% (early snow season) and 11.1% (late snow season) per degree of increased air temperature. For each degree of temperature increase, the modelled peak snow-water-equivalent (SWE) declined by 6.9%, duration of snowpack declined 11 days, and the number of days with rain increased 43% for the early snow season and 12.8% for the late snowseason. Awarmer climate also leads to markedly decreased surface snowsublimation and the fraction of snowfall eroded and transported by blowing snow. For most snowpack parameters analyzed, the response to warming accelerates with increased warming, especially above 3 °C. A 25% increase in precipitation partially counteracted the response to warming, with the greatest effect on peak SWE.
    Repository Name: EPIC Alfred Wegener Institut
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  • 39
    facet.materialart.
    Unknown
    Elsevier
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 57 (2016): 129-136, doi:10.1016/j.shpsc.2016.02.003.
    Description: Embryos have different meanings for different people and in different contexts. Seen under the microscope, the biological embryo starts out as one cell and then becomes a bunch of cells. Gradually these divide and differentiate to make up the embryo, which in humans becomes a fetus at eight weeks, and then eventually a baby. At least, that happens in those cases that carry through normally and successfully. Yet a popular public perception imagines the embryo as already a little person in the very earliest stages of development, as if it were predictably to become an adult. In actuality, cells can combine, pull apart, and recombine in a variety of ways and still produce embryos, whereas most embryos never develop into adults at all. Biological embryos and popular imaginations of embryos diverge. This paper looks at some of the historical reasons for and social implications of that divergence.
    Description: Thanks to the National Science Foundation for support through a series of grants.
    Keywords: Embryos ; Microscopes ; Science and society ; Bioethics ; Science policy
    Repository Name: Woods Hole Open Access Server
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  • 40
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biochemical Pharmacology 110-111 (2016): 117-129, doi:10.1016/j.bcp.2016.04.012.
    Description: 6-Formylindolo[3,2-b]carbazole (FICZ) is a potent aryl hydrocarbon receptor (AHR) agonist that is efficiently metabolized by AHR-regulated cytochrome P4501 enzymes. FICZ is a proposed physiological AHR ligand that induces its own degradation as part of a regulatory negative feedback loop. In vitro studies in cells show that CYP1 inhibition in the presence of FICZ results in enhanced AHR activation, suggesting that FICZ accumulates in the cell when its metabolism is blocked. We used zebrafish (Danio rerio) embryos to investigate the in vivo effects of FICZ when CYP1A is knocked down or inhibited. Embryos were injected with morpholino antisense oligonucleotides targeting CYP1A (CYP1A-MO), Ahr2, or a combination of both. FICZ exposure of non-injected embryos or embryos injected with control morpholino had little effect. In CYP1A-MO-injected embryos, however, FICZ dramatically increased mortality, incidence and severity of pericardial edema and circulation failure, reduced hatching frequency, blocked swim bladder inflation, and strongly potentiated expression of Ahr2-regulated genes. These effects were substantially reduced in embryos with a combined knockdown of Ahr2 and CYP1A, indicating that the toxicity was mediated at least partly by Ahr2. Co-exposure to the CYP1 inhibitor alpha-naphthoflavone (αNF) and FICZ had similar effects as the combination of CYP1A-MO and FICZ. HPLC analysis of FICZ-exposed embryos showed increased levels of FICZ after concomitant CYP1A-MO injection or αNF co-exposure. Together, these results show that a functioning CYP1/AHR feedback loop is crucial for regulation of AHR signaling by a potential physiological ligand in vivo and further highlights the role of CYP1 enzymes in regulating biological effects of FICZ.
    Description: This work was supported by Swedish Research Council Formas grants 2011-963 (EW) and 2008-1249 (MJ), by a European Commission Horizon 2020 grant, Project ID 634880 (MJ), by a National Institute of Environmental Health Sciences (NIEHS) grant P42ES007381 (JJS and MEH), R01ES006272 (MEH) and F32ES017585 (ART-L), by Japan Society for the Promotion of Science Postdoctoral Fellowship for Research Abroad194313 (AK), by Grant-in-Aids for Research Activity Start-up26881001 (AK) and for Young Scientists (A)15H05334 (AK).
    Keywords: Aryl hydrocarbon receptor ; Cytochrome P4501 ; 6-Formylindolo[3,2-b]carbazole ; Enzyme inhibition ; Zebrafish embryo toxicity ; Synergistic receptor activation
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  • 41
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Protist 167 (2016): 106–120, doi:10.1016/j.protis.2016.01.003.
    Description: Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzooplankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding, we propose a new functional grouping of planktonic protists in an eco-physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity, (iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accordingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks.
    Description: This work was funded by grants to KJF and AM from the Leverhulme Trust (International Network Grant F00391 V) and NERC (UK) through its iMARNET programme NE/K001345/1.
    Keywords: Plankton functional types (PFTs) ; Phagotroph ; Phototroph ; Mixotroph ; Phytoplankton ; Microzooplankton
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  • 42
    Publication Date: 2022-05-26
    Description: Author Posting. © Oxford University Press, 2016. This article is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 205 (2016): 728-743, doi:10.1093/gji/ggw044.
    Description: While elasticity is a defining characteristic of the Earth's lithosphere, it is often ignored in numerical models of long-term tectonic processes in favour of a simpler viscoplastic description. Here we assess the consequences of this assumption on a well-studied geodynamic problem: the growth of normal faults at an extensional plate boundary. We conduct 2-D numerical simulations of extension in elastoplastic and viscoplastic layers using a finite difference, particle-in-cell numerical approach. Our models simulate a range of faulted layer thicknesses and extension rates, allowing us to quantify the role of elasticity on three key observables: fault-induced topography, fault rotation, and fault life span. In agreement with earlier studies, simulations carried out in elastoplastic layers produce rate-independent lithospheric flexure accompanied by rapid fault rotation and an inverse relationship between fault life span and faulted layer thickness. By contrast, models carried out with a viscoplastic lithosphere produce results that may qualitatively resemble the elastoplastic case, but depend strongly on the product of extension rate and layer viscosity U × ηL. When this product is high, fault growth initially generates little deformation of the footwall and hanging wall blocks, resulting in unrealistic, rigid block-offset in topography across the fault. This configuration progressively transitions into a regime where topographic decay associated with flexure is fully accommodated within the numerical domain. In addition, high U × ηL favours the sequential growth of multiple short-offset faults as opposed to a large-offset detachment. We interpret these results by comparing them to an analytical model for the fault-induced flexure of a thin viscous plate. The key to understanding the viscoplastic model results lies in the rate-dependence of the flexural wavelength of a viscous plate, and the strain rate dependence of the force increase associated with footwall and hanging wall bending. This behaviour produces unrealistic deformation patterns that can hinder the geological relevance of long-term rifting models that assume a viscoplastic rheology.
    Description: This work was supported by NSF grants OCE-11-54238 (JAO, MDB), EAR-10-10432 (MDB) and OCE-11-55098 (GI), as well as a WHOI Deep Exploration Institute grant and start-up support from the University of Idaho (EM).
    Keywords: Mid-ocean ridge processes ; Continental tectonics: extensional ; Lithospheric flexure ; Mechanics, theory, and modelling
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  • 43
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Conservation Physiology 4 (2016): cow014, doi:10.1093/conphys/cow014.
    Description: Reproduction of mysticete whales is difficult to monitor, and basic parameters, such as pregnancy rate and inter-calving interval, remain unknown for many populations. We hypothesized that baleen plates (keratinous strips that grow downward from the palate of mysticete whales) might record previous pregnancies, in the form of high-progesterone regions in the sections of baleen that grew while the whale was pregnant. To test this hypothesis, longitudinal baleen progesterone profiles from two adult female North Atlantic right whales (Eubalaena glacialis) that died as a result of ship strike were compared with dates of known pregnancies inferred from calf sightings and post-mortem data. We sampled a full-length baleen plate from each female at 4 cm intervals from base (newest baleen) to tip (oldest baleen), each interval representing ∼60 days of baleen growth, with high-progesterone areas then sampled at 2 or 1 cm intervals. Pulverized baleen powder was assayed for progesterone using enzyme immunoassay. The date of growth of each sampling location on the baleen plate was estimated based on the distance from the base of the plate and baleen growth rates derived from annual cycles of stable isotope ratios. Baleen progesterone profiles from both whales showed dramatic elevations (two orders of magnitude higher than baseline) in areas corresponding to known pregnancies. Baleen hormone analysis shows great potential for estimation of recent reproductive history, inter-calving interval and general reproductive biology in this species and, possibly, in other mysticete whales.
    Description: This work was supported by the Eppley Foundation for Research, the National Oceanographic and Atmospheric Administration Marine Mammal Health and Stranding Program and the Woods Hole Oceanographic Institution Ocean Life Institute.
    Keywords: Baleen ; Cetacea ; Marine mammals ; Pregnancy ; Progesterone ; Reproduction
    Repository Name: Woods Hole Open Access Server
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  • 44
    Publication Date: 2022-05-26
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Chemistry 177 (2015): 1-8, doi:10.1016/j.marchem.2015.04.005.
    Description: The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes.
    Description: We gratefully acknowledge financial support by the Scientific Committee on Oceanic Research (SCOR) through grants from the U.S. National Science Foundation, including grants OCE-0608600, OCE-0938349, and OCE-1243377. Financial support was also provided by the UK Natural Environment Research Council, the Ministry of Earth Science of India, the Centre National de Recherche Scientifique, l'Université Paul Sabatier de Toulouse, the Observatoire Midi-Pyrénées Toulouse, the Universitat Autònoma de Barcelona, the Kiel Excellence Cluster The Future Ocean, the Swedish Museum of Natural History, The University of Tokyo, The University of British Columbia, The Royal Netherlands Institute for Sea Research, the GEOMAR-Helmholtz Centre for Ocean Research Kiel, and the Alfred Wegener Institute.
    Keywords: GEOTRACES ; Trace elements ; Isotopes ; Electronic atlas
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  • 45
    Publication Date: 2022-05-26
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Journal of Volcanology and Geothermal Research 314 (2016): 142-155, doi:10.1016/j.jvolgeores.2015.07.037.
    Description: Autonomous underwater vehicles were used to conduct a high-resolution water column survey of Lake Rotomahana using temperature, pH, turbidity, and oxidation–reduction potential (ORP) to identify active hydrothermal discharge zones within the lake. Five areas with active sublacustrine venting were identified: (1) the area of the historic Pink Terraces; (2) adjacent to the western shoreline subaerial “Steaming Cliffs,” boiling springs and geyser; (3) along the northern shoreline to the east of the Pink Terrace site; (4) the newly discovered Patiti hydrothermal system along the south margin of the 1886 Tarawera eruption rift zone; and (5) a location in the east basin (northeast of Patiti Island). The Pink Terrace hydrothermal system was active prior to the 1886 eruption of Mount Tarawera, but venting along the western shoreline, in the east basin, and the Patiti hydrothermal system appear to have been initiated in the aftermath of the eruption, similar to Waimangu Valley to the southwest. Different combinations of turbidity, pH anomalies (both positive and negative), and ORP responses suggest vent fluid compositions vary over short distances within the lake. The seasonal period of stratification limits vertical transport of heat to the surface layer and the hypolimnion temperature of Lake Rotomahana consequently increases with an average warming rate of ~ 0.010 °C/day due to both convective hydrothermal discharge and conductive geothermal heating. A sudden temperature increase occurred during our 2011 survey and was likely the response to an earthquake swarm just 11 days prior.
    Description: Funding was provided by GNS Strategic Development Fund.
    Keywords: Lake Rotomahana ; Hydrothermal venting ; pH ; Turbidity ; Oxidation–reduction potential ; Freshwater lakes
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  • 46
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 176 (2016): 227–238, doi:10.1016/j.gca.2015.12.027.
    Description: Measurements of Xe isotope ratios in ocean island basalts (OIB) suggest that Earth’s mantle accreted heterogeneously, and that compositional remnants of accretion are sampled by modern, high-3He/4He OIB associated with the Icelandic and Samoan plumes. If so, the high-3He/4He source may also have a distinct oxygen isotopic composition from the rest of the mantle. Here, we test if the major elements of the high-3He/4He source preserve any evidence of heterogeneous accretion using measurements of three oxygen isotopes on olivine from a variety of high-3He/4He OIB locations. To high precision, the Δ17O value of high-3He/4He olivines from Hawaii, Pitcairn, Baffin Island and Samoa, are indistinguishable from bulk mantle olivine (Δ17OBulk Mantle − Δ17OHigh 3He/4He olivine = −0.002 ± 0.004 (2 × SEM)‰). Thus, there is no resolvable oxygen isotope evidence for heterogeneous accretion in the high-3He/4He source. Modelling of mixing processes indicates that if an early-forming, oxygen-isotope distinct mantle did exist, either the anomaly was extremely small, or the anomaly was homogenised away by later mantle convection. The δ18O values of olivine with the highest 3He/4He ratios from a variety of OIB locations have a relatively uniform composition (∼5‰). This composition is intermediate to values associated with the depleted MORB mantle and the average mantle. Similarly, δ18O values of olivine from high-3He/4He OIB correlate with radiogenic isotope ratios of He, Sr, and Nd. Combined, this suggests that magmatic oxygen is sourced from the same mantle as other, more incompatible elements and that the intermediate δ18O value is a feature of the high-3He/4He mantle source. The processes responsible for the δ18O signature of high-3He/4He mantle are not certain, but δ18O–87Sr/86Sr correlations indicate that it may be connected to a predominance of a HIMU-like (high U/Pb) component or other moderate δ18O components recycled into the high-3He/4He source.
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  • 47
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2016. This article is posted here by permission of The Royal Astronomical Society for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 205 (2016): 785-795, doi:10.1093/gji/ggw036.
    Description: An L-configured, three-component short period seismic array was deployed on the Ross Ice Shelf, Antarctica during November 2014. Polarization analysis of ambient noise data from these stations shows linearly polarized waves for frequency bands between 0.2 and 2 Hz. A spectral peak at about 1.6 Hz is interpreted as the resonance frequency of the water column and is used to estimate the water layer thickness below the ice shelf. The frequency band from 4 to 18 Hz is dominated by Rayleigh and Love waves propagating from the north that, based on daily temporal variations, we conclude were generated by field camp activity. Frequency–slowness plots were calculated using beamforming. Resulting Love and Rayleigh wave dispersion curves were inverted for the shear wave velocity profile within the firn and ice to ∼150 m depth. The derived density profile allows estimation of the pore close-off depth and the firn–air content thickness. Separate inversions of Rayleigh and Love wave dispersion curves give different shear wave velocity profiles within the firn. We attribute this difference to an effective anisotropy due to fine layering. The layered structure of firn, ice, water and the seafloor results in a characteristic dispersion curve below 7 Hz. Forward modelling the observed Rayleigh wave dispersion curves using representative firn, ice, water and sediment structures indicates that Rayleigh waves are observed when wavelengths are long enough to span the distance from the ice shelf surface to the seafloor. The forward modelling shows that analysis of seismic data from an ice shelf provides the possibility of resolving ice shelf thickness, water column thickness and the physical properties of the ice shelf and underlying seafloor using passive-source seismic data.
    Description: PDB, AD and PG were supported by NSF Grant PLR 1246151. RAS was supported by NSF Grant PLR-1246416. DAW, RA and AN were supported under NSF Grants PLR-1142518, 1141916 and 1142126, respectively. PDB also received support from the California Department of Parks and Recreation, Division of Boating and Waterways under contract 11-106-107.
    Keywords: Glaciology ; Surface waves and free oscillations ; Seismic anisotropy ; Antarctica
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  • 48
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ocean Modelling 105 (2016): 1-12, doi:10.1016/j.ocemod.2016.02.009
    Description: The sea state of the Beaufort and Chukchi seas is controlled by the wind forcing and the amount of ice-free water available to generate surface waves. Clear trends in the annual duration of the open water season and in the extent of the seasonal sea ice minimum suggest that the sea state should be increasing, independent of changes in the wind forcing. Wave model hindcasts from four selected years spanning recent conditions are consistent with this expectation. In particular, larger waves are more common in years with less summer sea ice and/or a longer open water season, and peak wave periods are generally longer. The increase in wave energy may affect both the coastal zones and the remaining summer ice pack, as well as delay the autumn ice-edge advance. However, trends in the amount of wave energy impinging on the ice-edge are inconclusive, and the associated processes, especially in the autumn period of new ice formation, have yet to be well-described by in situ observations. There is an implicit trend and evidence for increasing wave energy along the coast of northern Alaska, and this coastal signal is corroborated by satellite altimeter estimates of wave energy.
    Description: This work was supported by the Office of Naval Research, Code 322, “Arctic and Global Prediction”, directed by Drs. Martin Jeffries and Scott Harper. (Grant numbers and Principal Investigators are: Ackley, N000141310435; Babanin, N000141310278; Doble, N000141310290; Fairall, N0001413IP20046; Gemmrich, N000141310280; Girard-Ardhuin and Ardhuin, N000141612376; Graber, N000141310288; Guest, N0001413WX20830; Holt, N0001413IP20050; Lehner, N000141310303; Maksym, N000141310446; Perrie, N00014-15-1-2611; Rogers, N0001413WX20825; Shen, N000141310294; Squire, N000141310279; Stammerjohn, N000141310434; Thomson, N000141310284; Wadhams, N000141310289.)
    Keywords: Sea ice ; Arctic Ocean ; Ocean surface waves
    Repository Name: Woods Hole Open Access Server
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  • 49
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 179 (2016): 123-141, doi:10.1016/j.gca.2016.01.023.
    Description: The carbonate clumped isotope thermometer is a promising tool for determining past ocean temperatures. It is based on the temperature dependence of rare isotopes ‘clumping’ into the same carbonate ion group in the carbonate mineral lattice. The extent of this clumping effect is independent of the isotope composition of the water from which carbonate precipitates, providing unique advantages over many other paleotemperature proxies. Existing calibrations of this thermometer in cold-water and warm-water corals suggest clumped isotope ‘vital effects’ are negligible in cold-water corals but may be significant in warm-water corals. Here, we test the calibration of the carbonate clumped isotope thermometer in cold-water corals with a recently collected and well characterised sample set spanning a range of coral genera (Balanophyllia, Caryophyllia, Dasmosmilia, Desmophyllum, Enallopsammia and Javania). The clumped isotope compositions (Δ47) of these corals exhibit systematic dependences on their growth temperatures, confirming the basis of the carbonate clumped isotope thermometer. However, some cold-water coral genera show Δ47 values that are higher than the expected equilibrium values by up to 0.05‰ (equivalent to underestimating temperature by ∼9 °C) similar to previous findings for some warm-water corals. This finding suggests that the vital effects affecting corals Δ47 are common to both warm- and cold-water corals. By comparison with models of the coral calcification process we suggest that the clumped isotope offsets in these genera are related to the kinetic isotope effects associated with CO2 hydration/hydroxylation reactions in the corals’ calcifying fluid. Our findings complicate the use of the carbonate clumped isotope thermometer in corals, but suggest that species- or genus-specific calibrations could be useful for the future application of this paleotemperature proxy.
    Description: This work was supported by a British National Environment Research Council studentship to P. Spooner (NE/K500823/1), National Science Foundation Grant NSF-ANT-1246387 and The Penzance Endowed Fund in Support of Assistant Scientists (WHOI) to W. Guo, and by funds from the European Research Council, the Leverhulme Trust and a Marie Curie Reintegration grant.
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  • 50
    Publication Date: 2022-05-26
    Description: © International Council for the Exploration of the Sea, 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in ICES Journal of Marine Science 73 (2016): 1839-1850, doi: 10.1093/icesjms/fsw086.
    Description: For terrestrial and marine benthic ecologists, landscape ecology provides a framework to address issues of complexity, patchiness, and scale—providing theory and context for ecosystem based management in a changing climate. Marine pelagic ecosystems are likewise changing in response to warming, changing chemistry, and resource exploitation. However, unlike spatial landscapes that migrate slowly with time, pelagic seascapes are embedded in a turbulent, advective ocean. Adaptations from landscape ecology to marine pelagic ecosystem management must consider the nature and scale of biophysical interactions associated with organisms ranging from microbes to whales, a hierarchical organization shaped by physical processes, and our limited capacity to observe and monitor these phenomena across global oceans. High frequency, multiscale, and synoptic characterization of the 4-D variability of seascapes are now available through improved classification methods, a maturing array of satellite remote sensing products, advances in autonomous sampling of multiple levels of biological complexity, and emergence of observational networks. Merging of oceanographic and ecological paradigms will be necessary to observe, manage, and conserve species embedded in a dynamic seascape mosaic, where the boundaries, extent, and location of features change with time.
    Description: This work was supported by NASA grant NNX14AP62A “National Marine Sanctuaries as Sentinel Sites for a Demonstration Marine Biodiversity Observation Network (MBON)” funded under the National Ocean Partnership Program (NOPP RFP NOAA-NOS-IOOS-2014-2003803 in partnership between NOAA, BOEM, and NASA), the NOAA Integrated Ocean Observing System (IOOS) Program Office, and the LenFest Ocean Program.
    Keywords: Biodiversity ; Conservation ; Landscape ; Ocean observations ; Pelagic ; Phytoplankton ; Seascape
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  • 51
    Publication Date: 2022-05-26
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Earth and Planetary Science Letters 449 (2016): 332–344, doi:10.1016/j.epsl.2016.05.023.
    Description: The recent discovery of active methane venting along the US northern and mid-Atlantic margin represents a new source of global methane not previously accounted for in carbon budgets from this region. However, uncertainty remains as to the origin and history of methane seepage along this tectonically inactive passive margin. Here we present the first isotopic analyses of authigenic carbonates and methanotrophic deep-sea mussels, Bathymodiolus sp., and the first direct constraints on the timing of past methane emission, based on samples collected at the upper slope Baltimore Canyon (∼385 m water depth) and deepwater Norfolk (∼1600 m) seep fields within the area of newly-discovered venting. The authigenic carbonates at both sites were dominated by aragonite, with an average View the MathML sourceδC13 signature of −47‰−47‰, a value consistent with microbially driven anaerobic oxidation of methane-rich fluids occurring at or near the sediment–water interface. Authigenic carbonate U and Sr isotope data further support the inference of carbonate precipitation from seawater-derived fluids rather than from formation fluids from deep aquifers. Carbonate stable and radiocarbon (View the MathML sourceδC13 and View the MathML sourceΔC13) isotope values from living Bathymodiolus sp. specimens are lighter than those of seawater dissolved inorganic carbon, highlighting the influence of fossil carbon from methane on carbonate precipitation. U–Th dates on authigenic carbonates suggest seepage at Baltimore Canyon between 14.7±0.6 ka14.7±0.6 ka to 15.7±1.6 ka15.7±1.6 ka, and at the Norfolk seep field between 1.0±0.7 ka1.0±0.7 ka to 3.3±1.3 ka3.3±1.3 ka, providing constraint on the longevity of methane efflux at these sites. The age of the brecciated authigenic carbonates and the occurrence of pockmarks at the Baltimore Canyon upper slope could suggest a link between sediment delivery during Pleistocene sea-level lowstand, accumulation of pore fluid overpressure from sediment compaction, and release of overpressure through subsequent venting. Calculations show that the Baltimore Canyon site probably has not been within the gas hydrate stability zone (GHSZ) in the past 20 ka, meaning that in-situ release of methane from dissociating gas hydrate cannot be sustaining the seep. We cannot rule out updip migration of methane from dissociation of gas hydrate that occurs farther down the slope as a source of the venting at Baltimore Canyon, but consider that the history of rapid sediment accumulation and overpressure may play a more important role in methane emissions at this site.
    Description: Funding for this project (sponsored by the National Oceanographic Partnership Program) included USGS Terrestrial, Freshwater, and Marine Environments Program through the Outer Continental shelf study, Coastal and Marine Geology Program, and the Bureau of Ocean Energy Management (BOEM) contract number M10PC00100 (contracted to CSA Ocean Sciences, Inc.). C.R. was supported by USGS–DOE Interagency Agreements DE-FE000291 and 0023495.
    Keywords: Authigenic carbonate ; Cold seep ; AOM ; Chemosynthesis ; Mid-Atlantic margin ; Isotope geochemistry
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 52
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Earth and Planetary Science Letters 449 (2016): 372-381, doi:10.1016/j.epsl.2016.05.016.
    Description: Although boron and uranium to calcium ratios (B/Ca, U/Ca) in planktonic foraminifera have recently received much attention as potential proxies for ocean carbonate chemistry, the extent of a carbonate chemistry control on these ratios remains contentious. Here, we use bi-weekly sediment trap samples collected from the subtropical North Atlantic in combination with measured oceanographic data from the same location to evaluate the dominant oceanographic controls on B/Ca and U/Ca in three depth-stratified species of planktonic foraminifera. We also test the control of biological, growth-related, processes on planktonic foraminiferal B and U incorporation by using foraminifer test area density (μg/μm2)(μg/μm2) (a monitor of test thickness) and test size from the same samples. B/Ca and U/Ca show little or no significant correlation with carbonate system parameters both within this study and in comparison with other published works. We provide the first evidence for a strong positive relationship between area density (test thickness) and B/Ca, and reveal that this is consistent in all species studied, suggesting a likely role for calcification in controlling boron partitioning into foraminiferal calcite. This finding is consistent with previous observations of less efficient discrimination against trace element ‘impurities’ (such as B), at higher calcification rates. We observe little or no dependency of B/Ca on test size. In marked contrast, we find that U/Ca displays a strong species-specific dependency on test size in all species, but no relationship with test thickness, implicating some other biological control (possibly related to growth), rather than a calcification control, on U incorporation into foraminiferal calcite. Our results caution against the use of B/Ca and U/Ca in planktonic foraminifera as reliable proxies for the ocean carbonate system and recommend that future work should concentrate on improving the mechanistic understanding of how planktonic foraminifer calcification and growth rates regulate boron and uranium incorporation into the test.
    Description: This research was funded through the U.K. Ocean Acidification Research Program by Natural Environment Research Council grant to P. Anand and P. Sexton (grant NE/I019891/1). K.S. thanks the Cushman Foundation for their financial support through the Johanna Resig Foraminifera Fellowship. We acknowledge the National Science Foundation for its support of the Oceanic Flux Program time-series (most recently by grant OCE-1234292) and the Bermuda Atlantic Time Series (most recently by grant OCE-0801991).
    Keywords: Planktonic foraminifera ; Boron ; Uranium ; Proxy ; Sediment trap
    Repository Name: Woods Hole Open Access Server
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  • 53
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters B 294 (1992), S. 466-478 
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 54
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters B 317 (1993), S. 474-484 
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 55
    Publication Date: 2016-07-10
    Description: Differential exposure to multiple environmental burdens and benefits and their distribution across a population with varying vulnerability can contribute heavily to health inequalities. Particularly relevant are areas with high cumulative burdens and high social vulnerability termed as “hotspots”. This paper develops an index-based approach to assess these multiple burdens and benefits in combination with vulnerability factors at detailed intra-urban level. The method is applied to the city of Dortmund, Germany. Using non-spatial and spatial methods we assessed inequalities and identified “hotspot” areas in the city. We found modest inequalities burdening higher vulnerable groups in Dortmund (CI = −0.020 at p 〈 0.05). At the detailed intra-urban level, however, inequalities showed strong geographical patterns. Large numbers of “hotspots” exist in the northern part of the city compared to the southern part. A holistic assessment, particularly at a detailed local level, considering both environmental burdens and benefits and their distribution across the population with the different vulnerability, is essential to inform environmental justice debates and to mobilize local stakeholders. Locating “hotspot” areas at this detailed spatial level can serve as a basis to develop interventions that target vulnerable groups to ensure a health conducive equal environment.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 56
    Publication Date: 2016-07-10
    Description: The goal of the study was to assess the quality of life (QOL) and depression and provide further insights into the relationship between QOL and depression among community-dwelling elderly Chinese people. Baseline data were collected from 1168 older adults (aged ≥ 60) in a large, prospective cohort study on measurement and evaluation of health-promoting and health-protecting behaviors intervention on chronic disease in different community-dwelling age groups. QOL was assessed using the 26-item, World Health Organization Quality of Life, brief version (WHOQOL-BREF) and depression was assessed using the 30-item Geriatric Depression Scale (GDS). The mean WHOQOL-BREF score for all dimensions was approximately 60, with the highest mean value (61.92) observed for social relationships, followed by environment, physical health, and psychological health domains. In this cohort, 26.1% of elderly urban adults met GDS criteria for depression. There were negative correlations between physical health (Odds Ratio (OR) = 0.928, 95% Confidence Interval (CI): 0.910–0.946), psychological health (OR = 0.906, 95% CI: 0.879–0.934), environment (OR = 0.966, 95% CI: 0.944–0.989) and depression among elderly people. Those with depression were older, less educated, had a lower monthly income, and were more likely to report insomnia. All WHOQOL-BREF domains, with the exception of the social domain were negatively correlated with depression.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 57
    Publication Date: 2016-07-10
    Description: Background: Measuring mercury in newborn bloodspots to determine fetal exposures is a novel methodology with many advantages. Questions remain, however, about its reliability as an estimate of newborn exposure to mercury. Methods: We studied mercury concentrations in paired bloodspots and cord blood from a convenience sample of 48 Minnesota women and infants. Results: The limit of detection for bloodspots was higher than for cord blood (0.7 and 0.3 μg/L in bloodspots and cord blood, respectively) with the result that mercury was detected in only 38% of newborn bloodspots compared to 62% of cord blood samples. The geometric mean mercury concentration in cord blood was 0.6 μg/L. Mercury concentrations were almost uniformly lower in bloodspots than in cord blood (mean ratio (±SD) = 0.85 ± 0.4), their mean value was significantly less than that for the cord blood (p = 0.02), and the two methods were highly correlated (r = 0.82). Conclusion: These preliminary findings indicate that newborn bloodspot mercury measurements have utility; however, until bloodspot analyses are more sensitive, they are likely to underestimate in utero exposure.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 58
    Publication Date: 2016-07-12
    Description: Materials based on biodegradable polyesters, such as poly(butylene terephthalate) (PBT) or poly(butylene terephthalate-co-poly(alkylene glycol) terephthalate) (PBTAT), have potential application as pro-regenerative scaffolds for bone tissue engineering. Herein, the preparation of films composed of PBT or PBTAT and an engineered spider silk protein, (eADF4(C16)), that displays multiple carboxylic acid moieties capable of binding calcium ions and facilitating their biomineralization with calcium carbonate or calcium phosphate is reported. Human mesenchymal stem cells cultured on films mineralized with calcium phosphate show enhanced levels of alkaline phosphatase activity suggesting that such composites have potential use for bone tissue engineering.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by MDPI Publishing
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  • 59
    Publication Date: 2016-07-10
    Description: Bioleaching is the mobilization of metal cations from insoluble ores by microorganisms. Biofilms can enhance this process. Since Sulfobacillus often appears in leaching heaps or reactors, this genus has aroused attention. In this study, biofilm formation and subsequent pyrite dissolution by the Gram-positive, moderately thermophilic acidophile Sulfobacillus thermosulfidooxidans were investigated. Five strategies, including adjusting initial pH, supplementing an extra energy source or ferric ions, as well as exchanging exhausted medium with fresh medium, were tested for enhancement of its biofilm formation. The results show that regularly exchanging exhausted medium leads to a continuous biofilm development on pyrite. By this way, multiply layered biofilms were observed on pyrite slices, while only monolayer biofilms were visible on pyrite grains. In addition, biofilms were proven to be responsible for pyrite leaching in the early stages.
    Electronic ISSN: 2075-163X
    Topics: Geosciences
    Published by MDPI Publishing
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  • 60
    Publication Date: 2016-07-10
    Description: The objective of this study was to assess the performance of the simulated start of the photosynthetically active season by a large-scale biosphere model in boreal forests in Finland with remote sensing observations. The start of season for two forest types, evergreen needle- and deciduous broad-leaf, was obtained for the period 2003–2011 from regional JSBACH (Jena Scheme for Biosphere–Atmosphere Hamburg) runs, driven with climate variables from a regional climate model. The satellite-derived start of season was determined from daily Moderate Resolution Imaging Spectrometer (MODIS) time series of Fractional Snow Cover and the Normalized Difference Water Index by applying methods that were targeted to the two forest types. The accuracy of the satellite-derived start of season in deciduous forest was assessed with bud break observations of birch and a root mean square error of seven days was obtained. The evaluation of JSBACH modelled start of season dates with satellite observations revealed high spatial correspondence. The bias was less than five days for both forest types but showed regional differences that need further consideration. The agreement with satellite observations was slightly better for the evergreen than for the deciduous forest. Nonetheless, comparison with gross primary production (GPP) determined from CO2 flux measurements at two eddy covariance sites in evergreen forest revealed that the JSBACH-simulated GPP was higher in early spring and led to too-early simulated start of season dates. Photosynthetic activity recovers differently in evergreen and deciduous forests. While for the deciduous forest calibration of phenology alone could improve the performance of JSBACH, for the evergreen forest, changes such as seasonality of temperature response, would need to be introduced to the photosynthetic capacity to improve the temporal development of gross primary production.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
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  • 61
    Publication Date: 2016-07-10
    Description: An innovative remote sensing approach that combines land-use change and water quality information is proposed in order to investigate if Artisanal and Small-scale Gold Mining (ASGM) area extension is associated with water siltation in the Tapajós River Basin (Brazil), containing the largest small-scale gold mining district in the world. Taking advantage of a 40-year period of the multi-satellite imagery archive, the objective of this paper is to build a normalized time-series in order to evaluate the influence of temporal mining expansion on the water siltation data (TSS, Total Suspended Solids concentration) derived from previous research. The methodological approach was set to deliver a full characterization of the ASGM expansion from its initial stages in the early 1970s to the present. First, based on IRS/LISSIII images acquired in 2012, the historical Landsat image database (1973–2001) was corrected for radiometric and atmospheric effects using dark vegetation as reference to create a normalized time-series. Next, a complete update of the mining areas distribution in 2012 derived from the TerraClass Project (an official land-use classification for the Brazilian Amazon) was conducted having IRS/LISSIII as the base map with the support of auxiliary data and vector editing. Once the ASGM in 2012 was quantified (261.7 km2) and validated with photos, a reverse classification of ASGM in 2001 (171.7 km2), 1993 (166.3 km2), 1984 (47.5 km2), and 1973 (15.4 km2) with the use of Landsat archives was applied. This procedure relies on the assumption that ASGM changes in the land cover are severe and remain detectable from satellite sensors for decades. The mining expansion area over time was then combined with the (TSS) data retrieved from the same atmospherically corrected satellite imagery based on the literature. In terms of gold mining expansion and water siltation effects, four main periods of ASGM activities were identified in the study area: (i) 1958–1977, first occurrence of mining activities and low water impacts; (ii) 1978–1993, introduction of low-budget mechanization associated with very high gold prices resulting in large mining area expansion and high water siltation levels; (iii) 1994–2003, general recession of ASGM activities and exhaustion of easy-access gold deposits, resulting in decreased TSS; (iv) 2004 to present, intensification of ASGM encouraged by high gold prices, resulting in an increase of TSS.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
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  • 62
    Publication Date: 2016-07-10
    Description: Current earth observation models do not take into account the influence of water salinity on the evaporation rate, even though the salinity influences the evaporation rate by affecting the density and latent heat of vaporization. In this paper, we adapt the SEBS (Surface Energy Balance System) model for large water bodies and add the effect of water salinity to the evaporation rate. Firstly, SEBS is modified for fresh-water whereby new parameterizations of the water heat flux and sensible heat flux are suggested. This is achieved by adapting the roughness heights for momentum and heat transfer. Secondly, a salinity correction factor is integrated into the adapted model. Eddy covariance measurements over Lake IJsselmeer (The Netherlands) are carried out and used to estimate the roughness heights for momentum (~0.0002 m) and heat transfer (~0.0001 m). Application of these values over the Victoria and Tana lakes (freshwater) in Africa showed that the calculated latent heat fluxes agree well with the measurements. The root mean-square of relative-errors (rRMSE) is about 4.1% for Lake Victoria and 4.7%, for Lake Tana. Verification with ECMWF data showed that the salinity reduced the evaporation at varying levels by up to 27% in the Great Salt Lake and by 1% for open ocean. Our results show the importance of salinity to the evaporation rate and the suitability of the adapted-SEBS model (AquaSEBS) for fresh and saline waters.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
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  • 63
    Publication Date: 2016-07-10
    Description: Area-based analyses of airborne laser scanning (ALS) data are an established approach to obtain wall-to-wall predictions of forest characteristics for vast areas. The analyses of sparse data in particular are based on the height value distributions, which do not produce optimal information on the horizontal forest structure. We evaluated the complementary potential of features quantifying the textural variation of ALS-based canopy height models (CHMs) for both supervised (linear regression) and unsupervised (k-Means clustering) analyses. Based on a comprehensive literature review, we identified a total of four texture analysis methods that produced rotation-invariant features of different order and scale. The CHMs and the textural features were derived from practical sparse-density, leaf-off ALS data originally acquired for ground elevation modeling. The features were extracted from a circular window of 254 m2 and related with boreal forest characteristics observed from altogether 155 field sample plots. Features based on gray-level histograms, distribution of forest patches, and gray-level co-occurrence matrices were related with plot volume, basal area, and mean diameter with coefficients of determination (R2) of up to 0.63–0.70, whereas features that measured the uniformity of local binary patterns of the CHMs performed poorer. Overall, the textural features compared favorably with benchmark features based on the point data, indicating that the textural features contain additional information useful for the prediction of forest characteristics. Due to the developed processing routines for raster data, the CHM features may potentially be extracted with a lower computational burden, which promotes their use for applications such as pre-stratification or guiding the field plot sampling based solely on ALS data.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
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  • 64
    Publication Date: 2016-07-12
    Description: Presence of speech and motion artifacts has been shown to impact the performance of wearable sensor systems used for automatic detection of food intake. This work presents a novel wearable device which can detect food intake even when the user is physically active and/or talking. The device consists of a piezoelectric strain sensor placed on the temporalis muscle, an accelerometer, and a data acquisition module connected to the temple of eyeglasses. Data from 10 participants was collected while they performed activities including quiet sitting, talking, eating while sitting, eating while walking, and walking. Piezoelectric strain sensor and accelerometer signals were divided into non-overlapping epochs of 3 s; four features were computed for each signal. To differentiate between eating and not eating, as well as between sedentary postures and physical activity, two multiclass classification approaches are presented. The first approach used a single classifier with sensor fusion and the second approach used two-stage classification. The best results were achieved when two separate linear support vector machine (SVM) classifiers were trained for food intake and activity detection, and their results were combined using a decision tree (two-stage classification) to determine the final class. This approach resulted in an average F1-score of 99.85% and area under the curve (AUC) of 0.99 for multiclass classification. With its ability to differentiate between food intake and activity level, this device may potentially be used for tracking both energy intake and energy expenditure.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
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  • 65
    Publication Date: 2016-07-12
    Description: The Internet of Things (IoT) has made it possible for devices around the world to acquire information and store it, in order to be able to use it at a later stage. However, this potential opportunity is often not exploited because of the excessively big interval between the data collection and the capability to process and analyse it. In this paper, we review the current IoT technologies, approaches and models in order to discover what challenges need to be met to make more sense of data. The main goal of this paper is to review the surveys related to IoT in order to provide well integrated and context aware intelligent services for IoT. Moreover, we present a state-of-the-art of IoT from the context aware perspective that allows the integration of IoT and social networks in the emerging Social Internet of Things (SIoT) term.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
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  • 66
    Publication Date: 2016-07-10
    Description: Surrounded by the ocean, Taiwan has been increasingly developing coastal tourism projects. Concerns that negative impacts might be brought about by prosperous tourism have resulted in a recent focus on sustainable tourism. Sustainable tourism involves policies that acknowledge the interdependences among the environment, the community, and the economy. The goal of sustainable tourism is to enhance and protect the environment while satisfying basic human requirements, as well as those of the contemporary and future tourism industries to improve quality of life. On the other hand, unsustainable coastal tourism might undermine the natural environment and society, resulting in air, water, and soil pollution, wildlife habitat disruption, and changes of local community cultural characteristics. Therefore, performance evaluation of coastal tourism, using an indicator framework to facilitate sustainable development and enhance the effectiveness of coastal resources exploitation, is critical. Through a literature review and expert surveys using the methods of the fuzzy Delphi method (FDM) and the fuzzy analytic hierarchy process (FAHP), this study builds a performance indicator framework and identifies the key factors affecting the sustainable development of coastal tourism in Taiwan. The results can serve as a reference for the public sector to be used for the sustainable planning and development of coastal tourism.
    Electronic ISSN: 2071-1050
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 67
    Publication Date: 2016-07-10
    Description: Many countries and scholars have used various strategies to improve and optimize the allocation ratios for carbon emission allowances. This issue is more urgent for China due to the uneven development across the country. This paper proposes a new method that divides low-carbon economy development processes into two separate periods: from 2020 to 2029 and from 2030 to 2050. These two periods have unique requirements and emissions reduction potential; therefore, they must involve different allocation methods, so that reduction behaviors do not stall the development of regional low-carbon economies. During the first period, a more deterministic economic development approach for the carbon emission allowance allocation ratio should be used. During the second period, more adaptive and optimized policy guidance should be employed. We developed a low-carbon economy index evaluation system using the entropy weight method to measure information filtering levels. We conducted vector autoregressive correlation tests, consulted 60 experts for the fuzzy analytic hierarchy process, and we conducted max-min standardized data processing tests. This article presents first- and second-period carbon emission allowance models in combination with a low-carbon economy index evaluation system. Finally, we forecast reasonable carbon emission allowance allocation ratios for China for the periods starting in 2020 and 2030. A good allocation ratio for the carbon emission allowance can help boost China’s economic development and help the country reach its energy conservation and emissions reduction goals.
    Electronic ISSN: 2071-1050
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 68
    Publication Date: 2016-07-10
    Description: In the Internet of Things era, panel displays play a major role in human life, because humans frequently use liquid crystal displays to monitor their electrical devices. The display industry creates remarkable economic output, but every manufacturing process inevitably has some undesirable effects on the environment. With the increasing awareness of environmental protection, balanced development is necessary to address the emerging market trends. However, short-sighted manufacturing corporations that focus solely on financial performance can achieve only short-term profits. The purpose of this study was to develop the most effective sustainable improvement strategies that can enhance competitive advantages in real-world situations. The proposed method combines the balanced scorecard and a new hybrid modified multiple attribute decision-making model which together adopt the DEMATEL technique to construct the influential network relation map and develop the DEMATEL-based ANP with the VIKOR method to deliver strategies that integrate environmental sustainability and competitive advantage. Finally, a real-world case study applying the proposed method to the cases of liquid crystal display manufacturers was conducted. Then, this paper discusses the effective use of natural resources, development of enterprises, and sustainable competitive advantage in this context. Various manufacturers, communities, and stakeholders can benefit from the coopetition solutions explained by the proposed method.
    Electronic ISSN: 2071-1050
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 69
    Publication Date: 2016-07-10
    Description: Soil is the most basic resource for sustainable agricultural production; it promotes water quality, is a key component of the biogeochemical cycles and hosts a huge diversity of organisms. However, we are not paying enough attention to soil degradation produced by land use. Modern agriculture has been successful in increasing yields but has also caused extensive environmental damage, particularly soil degradation. In the Argentine Pampas, agriculturization reached a peak with the generalized use of the no-till technological package: genetically modified soybeans tolerant to glyphosate, no-till, glyphosate, and inorganic fertilizers. This phenomenon has been widely spread in the country; the no-till package has been applied in large areas and has been used by tenants in a 60%–70% of cultivated lands. Thus, those who were involved in developing management practices may not be the same as those who will face degradation issues related to those practices. Indeed, most evidence reviewed in this paper suggests that the most widely distributed practices in the Pampas region are actually producing severe soil degradation. Biological degradation is particularly important because soil biota is involved in numerous soil processes on which soil functioning relies, affecting soil fertility and productivity. For example, soil meso- and macrofauna are especially important in nutrient cycling and in soil structure formation and maintenance, and they are key components of the network that links microbial process to the scale of fields and landscapes where ecosystem services are produced. However, the knowledge of the impact of different agricultural managements on soil meso- and macrofauna in Pampas agroecosystems is far from conclusive at this stage. The reason for this lack of definite conclusions is that this area has been given less attention than in other parts of the world; the response of soil fauna to agricultural practices is complex and taxa-dependent; and there is a wide variety of practices in the main types of agricultural systems, making generalizations difficult. A review of the existing studies on soil meso- and macrofauna in agroecosystems, revealed that (a) agricultural soils, regardless of farming system, are strongly modified in biological aspects compared to the same soils without human interventions; (b) there are no conclusive results about no-till benefits compared to reduced tillage or conventional tillage; (c) agricultural managements that are alternative to the traditional conventional systems are very poorly represented in research.
    Electronic ISSN: 2071-1050
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 70
    Publication Date: 2016-07-10
    Description: Rain gauge and satellite-retrieved data have been widely used in basin-scale hydrological applications. While rain gauges provide accurate measurements that are generally unevenly distributed in space, satellites offer spatially regular observations and common error prone retrieval. Comparative evaluation of gauge-based and satellite-based data is necessary in hydrological studies, as precipitation is the most important input in basin-scale water balance. This study uses quality-controlled rain gauge data and prevailing satellite products (Tropical Rainfall Measuring Mission (TRMM) 3B43, 3B42 and 3B42RT) to examine the consistency and discrepancies between them at different scales. Rain gauges and TRMM products were available in the Poyang Lake Basin, China, from 1998 to 2007 (3B42RT: 2000–2007). Our results show that the performance of TRMM products generally increases with increasing spatial scale. At both the monthly and annual scales, the accuracy is highest for TRMM 3B43, with 3B42 second and 3B42RT third. TRMM products generally overestimate precipitation because of a high frequency and degree of overestimation in light and moderate rain cases. At the daily scale, the accuracy is relatively low between TRMM 3B42 and 3B42RT. Meanwhile, the performances of TRMM 3B42 and 3B42RT are highly variable in different seasons. At both the basin and pixel scales, TRMM 3B43 and 3B42 exhibit significant discrepancies from July to September, performing worst in September. For TRMM 3B42RT, all statistical indices fluctuate and are low throughout the year, performing worst in July at the pixel scale and January at the basin scale. Furthermore, the spatial distributions of the statistical indices of TRMM 3B43 and 3B42 performed well, while TRMM 3B42RT displayed a poor performance.
    Electronic ISSN: 2073-4441
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 71
    Publication Date: 2016-07-10
    Description: Flood is a frequent natural hazard that has significant financial consequences for Australia. In Australia, physical losses caused by floods are commonly estimated by stage-damage functions. These methods usually consider only the depth of the water and the type of buildings at risk. However, flood damage is a complicated process, and it is dependent on a variety of factors which are rarely taken into account. This study explores the interaction, importance, and influence of water depth, flow velocity, water contamination, precautionary measures, emergency measures, flood experience, floor area, building value, building quality, and socioeconomic status. The study uses tree-based models (regression trees and bagging decision trees) and a dataset collected from 2012 to 2013 flood events in Queensland, which includes information on structural damages, impact parameters, and resistance variables. The tree-based approaches show water depth, floor area, precautionary measures, building value, and building quality to be important damage-influencing parameters. Furthermore, the performance of the tree-based models is validated and contrasted with the outcomes of a multi-parameter loss function (FLFArs) from Australia. The tree-based models are shown to be more accurate than the stage-damage function. Consequently, considering more parameters and taking advantage of tree-based models is recommended. The outcome is important for improving established Australian flood loss models and assisting decision-makers and insurance companies dealing with flood risk assessment.
    Electronic ISSN: 2073-4441
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 72
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    MDPI Publishing
    In: Water
    Publication Date: 2016-07-10
    Description: This paper recounts the environmental history of a main waterway in Northern Israel—the Kishon, and deploys this history to examine the evolution of Israel water policy as it struggled to bridge the growing gap between its ambitions of development and the realities of its limited water supply. The first part of the paper describes the decay of the Kishon since the early 1950s, and the multiple scientific, political and legal attempts to alleviate its misfortunes, and discusses the reasons for their failings. Some of these reasons were administrative by nature, but the paper suggests a deeper reason, rooted in the ideological core of the infant state that was overwhelmingly concerned with the development of its infrastructure, and invited the pioneering Israeli society to consider the demise of the Kishon as a necessary sacrifice for progress. The second part of the paper describes the late-20th century developments that allowed for the recovery of the ailing river. Changing social mores, the growing importance of environmental politics, the advance of Israel’s water technologies, and an environmental scandal that endowed the rehabilitation of the Kishon with a new political and moral meaning, have all contributed to the rehabilitation of the river. Once a testament for the sacrifices involved in a struggle to create a viable state, the Kishon has become a theater for a confident society that has triumphed in its struggle against nature.
    Electronic ISSN: 2073-4441
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 73
    Publication Date: 2016-07-11
    Description: Publication date: Available online 9 July 2016 Source: Geodesy and Geodynamics Author(s): Ruisha Li, Xi Zhang, Shouwen Gong, Hongtao Tang, Peng Jia The equation for determining cross-fault representative value is calculated based on hanging wall and foot wall reference level surfaces. The cross-fault data reliability are analyzed base on the stability of reference datum and observation points, thereby facilitating plotting of the representative value curves after removing interference. The spatial and temporal characteristics of fault deformation abnormalities before the 2016 Menyuan M s6.4 earthquake, as well as the fault-movement characteristics reflected by representative value, are summarized. The results show that many site trends had changed 1–3 years before the Menyuan M s6.4 earthquake in the Qilian Fault, reflecting certain background abnormalities. The short-term abnormalities centrally had appeared in the 6 months to 1 year period before the earthquake near and in the neighborhood of the source region, demonstrating a significantly increased number of short-term abnormalities. Many sites near and in the neighborhood of the source region had strengthened inverse activities or had changed from positive to inverse activities in the most recent 2–3 years, which reflect stress-field enhancements or adjustment features.
    Print ISSN: 1674-9847
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Published by Elsevier
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  • 74
    Publication Date: 2016-07-13
    Description: Although phosphorus limitation is common in freshwaters and bacteria are known to use dissolved organic phosphorus (DOP), little is known about how efficiently DOP compounds are taken up by individual bacterial taxa. Here, we assessed bacterial uptake of three model DOP substrates in two mountain lakes and examined whether DOP uptake followed concentration-dependent patterns. We determined bulk uptake rates by the bacterioplankton and examined bacterial taxon-specific substrate uptake patterns using microautoradiography combined with catalyzed reporter deposition–fluorescence in situ hybridization. Our results show that in the oligotrophic alpine lake, bacteria took up ATP, glucose-6-phosphate and glycerol-3-phosphate to similar extents (mean 29.7 ± 4.3% Bacteria ), whereas in the subalpine mesotrophic lake, ca. 40% of bacteria took up glucose-6-phosphate, but only ~20% took up ATP or glycerol-3-phosphate. In both lakes, the R-BT cluster of Betaproteobacteria (lineage of genus Limnohabitans ) was over-represented in glucose-6-phosphate and glycerol-3-phosphate uptake, whereas AcI Actinobacteria were under-represented in the uptake of those substrates. Alphaproteobacteria and Bacteroidetes contributed to DOP uptake proportionally to their in situ abundance. Our results demonstrate that R-BT Betaproteobacteria are the most active bacteria in DOP acquisition, whereas the abundant AcI Actinobacteria may either lack high affinity DOP uptake systems or have reduced phosphorus requirements.
    Print ISSN: 0168-6496
    Electronic ISSN: 1574-6941
    Topics: Biology
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  • 75
    Publication Date: 2016-07-13
    Description: Height models based on high-altitude aerial images provide a low-cost means of generating detailed 3D models of the forest canopy. In this study, the performance of these height models in the detection of individual trees was evaluated in a commercially managed boreal forest. Airborne digital stereo imagery (DSI) was captured from a flight altitude of 5 km with a ground sample distance of 50 cm and corresponds to regular national topographic airborne data capture programs operated in many countries. Tree tops were detected from smoothed canopy height models (CHM) using watershed segmentation. The relative amount of detected trees varied between 26% and 140%, and the RMSE of plot-level arithmetic mean height between 2.2 m and 3.1 m. Both the dominant tree species and the filter used for smoothing affected the results. Even though the spatial resolution of DSI-based CHM was sufficient, detecting individual trees from the data proved to be demanding because of the shading effect of the dominant trees and the limited amount of data from lower canopy levels and near the ground.
    Electronic ISSN: 1999-4907
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 76
    Publication Date: 2016-07-13
    Description: Thinning is one of the intensive forest management techniques commonly applied to increase the merchantable timber volume. However, how thinning affects soil–atmospheric fluxes of greenhouse gases (GHGs) is poorly understood. A field experiment with four treatments (CK: unthinned; MB: medium intensity thinning from below; HB: high intensity thinning from below; and HI: high intensity thinning by removing every alternative row of trees) was conducted to assess the impact of thinning regimes on soil–atmospheric fluxes of GHGs (CO2, CH4, and N2O) and soil nitrogen mineralization in a poplar plantation established on a lowland. Thinning significantly increased soil water content and water table in the high thinning treatments (HB and HI) and tended to increase soil temperature (p 〈 0.10). The result of the one-year study showed that estimated annual emissions of CO2 and CH4 were higher in HB and HI than in other treatments, while the highest emission of N2O was in the CK. The thinning treatments increased the annual emission of CO2 by 23%–64% and that of CH4 by 190%–1200%, but decreased that of N2O by 41%–62%. Thinning increased annual N mineralization by 50.3% in HI and 30.1%in HB. Changes in soil temperature and water table drove CO2, CH4, and N2O emissions, while soil water content was the most important factor driving CH4 emission. We conclude that the moderate thinning (MB) regime is the best thinning option to minimize the impact on GHG emissions for lowland poplar plantations with similar conditions to those tested in this study.
    Electronic ISSN: 1999-4907
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 77
    Publication Date: 2016-07-13
    Description: Severe crown fires are determining disturbances for the composition and structure of boreal forests in North America. Fire cycle (FC) associations with continental climate gradients are well known, but smaller scale controls remain poorly documented. Using a time since fire map (time scale of 300 years), the study aims to assess the relative contributions of local and regional controls on FC and to describe the relationship between FC heterogeneity and vegetation patterns. The study area, located in boreal eastern North America, was partitioned into watersheds according to five scales going from local (3 km2) to landscape (2800 km2) scales. Using survival analysis, we observed that dry surficial deposits and hydrography density better predict FC when measured at the local scale, while terrain complexity and slope position perform better when measured at the middle and landscape scales. The most parsimonious model was selected according to the Akaike information criterion to predict FC throughout the study area. We detected two FC zones, one short (159 years) and one long (303 years), with specific age structures and tree compositions. We argue that the local heterogeneity of the fire regime contributes to ecosystem diversity and must be considered in ecosystem management.
    Electronic ISSN: 1999-4907
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 78
    Publication Date: 2016-07-13
    Description: Earlier studies show that the proliferation of phytoplankton viruses can be inhibited by depletion of soluble reactive phosphorus (SRP; orthophosphate). In natural marine waters, phytoplankton phosphorus (P) availability is, however, largely determined by the supply rate of SRP (e.g. through remineralization) and potentially by the source of P as well (i.e. the utilization of soluble non-reactive P; SNP). Here we show how a steady low supply of P (mimicking natural P recycling) to virally infected P-limited Micromonas pusilla stimulates virus proliferation. Independent of the degree of P limitation prior to infection (0.32 and 0.97μ max chemostat cultures), SRP supply resulted in 2-fold higher viral burst sizes (viruses lysed per host cell) as compared with no addition (P starvation). Delaying these spikes during the infection cycle showed that the added SRP was utilized for extra M. pusilla virus (MpV) production far into the lytic cycle (18 h post-infection). Moreover, P-limited M. pusilla utilized several SNP compounds with high efficiency and with the same extent of burst size stimulation as for SRP. Finally, addition of virus-free MpV lysate (representing a complex SNP mixture) to newly infected cells enhanced MpV production, implicating host-associated alkaline phosphatase activity, and highlighting its important role in oligotrophic environments.
    Print ISSN: 0168-6496
    Electronic ISSN: 1574-6941
    Topics: Biology
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  • 79
    Publication Date: 2016-07-13
    Description: Converting secondary natural forests (SFs) to Chinese fir plantations (CFPs) represents one of the most important (8.9 million ha) land use changes in subtropical China. This study estimated both biomass and soil C stocks in a SF and a CFP that was converted from a SF, to quantify the effects of land use change on ecosystem C stock. After the forest conversion, biomass C in the CFP (73 Mg·ha−1) was significantly lower than that of the SF (114 Mg·ha−1). Soil organic C content and stock decreased with increasing soil depth, and the soil C stock in the 0–10 cm layer accounted for more than one third of the total soil C stock over 0–50 cm, emphasizing the importance of management of the top soil to reduce the soil C loss. Total ecosystem C stock of the SF and the CFP was 318 and 200 Mg·ha−1, respectively, 64% of which was soil C for both stands (205 Mg·ha−1 for the SF and 127 Mg·ha−1 for the CFP). This indicates that land use change from the SF to the CFP significantly decreased ecosystem C stock and highlights the importance of managing soil C.
    Electronic ISSN: 1999-4907
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 80
    Publication Date: 2016-07-13
    Description: Earth's free oscillations excited by a mega-thrust earthquake were observed by a continent-scale array of groundwater monitoring sites for the first time. After the occurrence of the 2011 Tohoku M w 9.0 earthquake, water level records at 43 out of 216 wells in the China mainland revealed long-period free oscillation signals. In the time domain, these free oscillations exhibit globe circling Rayleigh surface waves. In some single wells, even the globe-circling Rayleigh wave R7 was visible, which travels three times around the Earth after the first arrival and appears about 10 hr after the earthquake occurrence in the present case. The spectral analysis shows that the principal oscillatory fluctuations seen in the water level records correspond to the spheroidal modes 0 S l ( l  = 2–31 for frequencies between 0.3 and 5.0 mHz) of the Earth's free oscillation. Especially at quiet sites, the spheroidal modes at very low frequencies (〈1.5 mHz) can be identified with high signal-to-noise ratios. Using signal enhancement methods (product spectrum over 43 wells), even the gravest modes of these oscillations can be detected. The results suggest that groundwater level arrays can be considered as a low-cost complementary tool to study the Earth's free oscillations excited by great earthquakes. Additionally, the site-specific aquifer response may provide further insight into local hydrogeological conditions.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 81
    Publication Date: 2016-07-13
    Description: We performed numerical simulations of the 2011 deep-seated Akatani landslide in central Japan to understand the dynamic evolution of friction of the landslide. By comparing the forces obtained from numerical simulation to those resolved from seismic waveform inversion, the coefficient of the friction during sliding was investigated in the range of 0.1–0.4. The simulation assuming standard Coulomb friction shows that the forces obtained by the seismic waveform inversion are well explained using a constant friction of μ = 0.3. A small difference between the residuals of Coulomb simulation and a velocity-dependent simulation suggests that the coefficient of friction over the volume is well constrained as 0.3 most of time during sliding. It suggests the sudden loss of shearing resistance at the onset of sliding, that is, sudden drop of the initial coefficient of friction in our model, which accelerates the deep-seated landslide. Our numerical simulation calibrated by seismic data provides the evolution of dynamic friction with a reasonable resolution in time, which is difficult to obtain from a conventional runout simulation, or seismic waveform inversion alone.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 82
    Publication Date: 2016-07-13
    Description: We explore thermal convection of a fluid with a temperature-dependent viscosity in a basally heated 3-D spherical shell using linear stability analyses and numerical experiments, while considering the application of our results to terrestrial planets. The inner to outer radius ratio of the shell f assumed in the linear stability analyses is in the range of 0.11–0.88. The critical Rayleigh number R c for the onset of thermal convection decreases by two orders of magnitude as f increases from 0.11 to 0.88, when the viscosity depends sensitively on the temperature, as is the case for real mantle materials. Numerical simulations carried out in the range of f  = 0.11–0.55 show that a thermal boundary layer (TBL) develops both along the surface and bottom boundaries to induce cold and hot plumes, respectively, when f is 0.33 or larger. However, for smaller f values, a TBL develops only on the bottom boundary. Convection occurs in the stagnant-lid regime where the root mean square velocity on the surface boundary is less than 1 per cent of its maximum at depth, when the ratio of the viscosity at the surface boundary to that at the bottom boundary exceeds a threshold that depends on f . The threshold decreases from 10 6.5 at f  = 0.11 to 10 4 at f  = 0.55. If the viscosity at the base of the convecting mantle is 10 20 –10 21  Pa s, the Rayleigh number exceeds R c for Mars, Venus and the Earth, but does not for the Moon and Mercury; convection is unlikely to occur in the latter planets unless the mantle viscosity is much lower than 10 20  Pa s and/or the mantle contains a strong internal heat source.
    Keywords: Geodynamics and Tectonics
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 83
    Publication Date: 2016-07-13
    Description: Due to a mistake during the production process, there was one error in paragraph 3 of the introduction in the original published version [1].[...]
    Electronic ISSN: 1999-4907
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 84
    Publication Date: 2016-07-13
    Description: We introduce a technique to compute exact anelastic sensitivity kernels in the time domain using parsimonious disk storage. The method is based on a reordering of the time loop of time-domain forward/adjoint wave propagation solvers combined with the use of a memory buffer. It avoids instabilities that occur when time-reversing dissipative wave propagation simulations. The total number of required time steps is unchanged compared to usual acoustic or elastic approaches. The cost is reduced by a factor of 4/3 compared to the case in which anelasticity is partially accounted for by accommodating the effects of physical dispersion. We validate our technique by performing a test in which we compare the K α sensitivity kernel to the exact kernel obtained by saving the entire forward calculation. This benchmark confirms that our approach is also exact. We illustrate the importance of including full attenuation in the calculation of sensitivity kernels by showing significant differences with physical-dispersion-only kernels.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 85
    Publication Date: 2016-07-13
    Description: Subducting oceanic lithosphere is an example of a thin sheet-like object whose characteristic lateral dimension greatly exceeds its thickness. Here we exploit this property to derive a new hybrid boundary-integral/thin sheet (BITS) representation of subduction that combines in a single equation all the forces acting on the sheet: gravity, internal resistance to bending and stretching, and the tractions exerted by the ambient mantle. For simplicity, we limit ourselves to 2-D. We solve the BITS equations using a discrete Lagrangian approach in which the sheet is represented by a set of vertices connected by edges. Instantaneous solutions for the sinking speed of a slab attached to a trailing flat sheet obey a scaling law of the form V / V Stokes  = fct(St), where V Stokes is a characteristic Stokes sinking speed and St is the sheet's flexural stiffness. Time-dependent solutions for the evolution of the sheet's shape and thickness show that these are controlled by the viscosity ratio between the sheet and its surroundings. An important advantage of the BITS approach is the possibility of generalizing the sheet's rheology, either to a viscosity that varies along the sheet or to a non-Newtonian shear-thinning rheology.
    Keywords: Geodynamics and Tectonics
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 86
    Publication Date: 2016-07-13
    Description: Rock permeability is an important parameter for the formation evaluation. In this paper, a new method with streaming current is proposed to determine the sample permeability based on the electrokinetic effects, and is proved by the experimental measurements. Corresponding to this method, we have designed an experimental setup and a test system, then performed the streaming current (potential) and electro-osmosis pressure experiments with 23 sandstone samples at 0.05 mol l –1 NaCl solution. The streaming current (potential) coefficient and electro-osmosis pressure coefficient are obtained, respectively, with the experimental data at low frequencies with AC lock-in technique. The electrokinetic permeabilities are further calculated with these coefficients. The results are consistent well with the gas permeability measured with Darcy's law, which verifies the current method for estimating rock permeability. Our measurements are also analysed and compared with previous measurements. The results indicate that our method can reflect the essence of electrokinetic effects better and simplify the electrokinetic measurements as well. In addition, we discuss the influences of experimental artefacts (core holder and confining pressure installation) on the electrokinetic data. The results show that the trough phenomenon, appeared in frequency curves of streaming current (potential) coefficients, is induced by the resonance of the core-holder/vibrator system. This is important for the design of electrokinetic setup and the analysis of low-frequency response of the electrokinetic coupling coefficients.
    Keywords: Marine Geosciences and Applied Geophysics
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 87
    Publication Date: 2016-07-13
    Description: Real Earth media are not perfectly elastic. Instead, they attenuate propagating mechanical waves. This anelastic phenomenon in wave propagation can be modeled by a viscoelastic mechanical model consisting of several standard linear solids. Using this viscoelastic model, we approximate a constant Q over a frequency band of interest. We use a four-element viscoelastic model with a trade-off between accuracy and computational costs to incorporate Q into 2-D time-domain first-order velocity–stress wave equations. To improve the computational efficiency, we limit the Q in the model to a list of discrete values between 2 and 1000. The related stress and strain relaxation times that characterize the viscoelastic model are pre-calculated and stored in a database for use by the finite-difference calculation. A viscoelastic finite-difference scheme that is second order in time and fourth order in space is developed based on the MacCormack algorithm. The new method is validated by comparing the numerical result with analytical solutions that are calculated using the generalized reflection/transmission coefficient method. The synthetic seismograms exhibit greater than 95 per cent consistency in a two-layer viscoelastic model. The dispersion generated from the simulation is consistent with the Kolsky–Futterman dispersion relationship.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 88
    Publication Date: 2016-07-13
    Description: Seismology plays an important role in characterizing potential underground nuclear tests. Using broad-band digital seismic data from Northeast China, South Korea and Japan, we investigated the properties of the recent seismic event occurred in North Korea on 2016 January 6. Using a relative location method and choosing the previous 2006 explosion as the master event, the 2016 event was located within the North Korean nuclear test site, with its epicentre at latitude 41.3003°N and longitude 129.0678°E, approximately 900 m north and 500 m west of the previous event on 2013 February 12. Based on the error ellipse, the relocation uncertainty was approximately 70 m. Using the P / S spectral ratios, including Pg/Lg, Pn/Lg and Pn/Sn, as the discriminants, we identify the 2016 event as an explosion rather than an earthquake. The body-wave magnitude calculated from regional wave Lg is m b (Lg) equal to 4.7 ± 0.2. Adopting an empirical magnitude–yield relation, and assuming that the explosion is fully coupled and detonated at a normally scaled depth, we find that the seismic yield is about 4 kt, with the uncertainties allowing a range from 2 to 8 kt.
    Keywords: Express Letters, Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 89
    Publication Date: 2016-07-13
    Description: After 83 yr, the great normal-faulting earthquake of 1933 March 2, which took place off the Japan Trench and produced a devastating tsunami on the Sanriku coast and damaging waves in Hawaii, remains the largest recorded normal-faulting earthquake. This study uses advanced methods to investigate this event using far-field seismological and tsunami data and complements a sister study by Uchida et al. which used exclusively arrival times at Japanese stations. Our relocation of the main shock (39.22°N, 144.45°E, with a poorly constrained depth of less than 40 km) places it in the outer trench slope, below a seafloor depth of ~6500 m, in a region of horst-and-graben structure, with fault scarps approximately parallel to the axis of the Japan Trench. Relocated aftershocks show a band of genuine shallow aftershocks parallel to the Japan Trench under the outer trench slope and a region of post-mainshock events landward of the trench axis that occur over roughly the same latitude range and are thought to be the result of stress transfer to the interplate thrust boundary following the normal-faulting rupture. Based on a combination of P -wave first motions and inversion of surface wave spectral amplitudes, we propose a normal-faulting focal mechanism ( = 200°, = 61° and = 271°) and a seismic moment M 0 = (7 ± 1) x 10 28 dyn cm ( M w = 8.5). A wide variety of data, including the distribution of isoseismals, the large magnitudes (up to 8.9) proposed by early investigators before the standardization of magnitude scales, estimates of energy-to-moment ratios and the tentative identification of a T wave at Pasadena (and possibly Riverside), clearly indicate that this seismic source was exceptionally rich in high-frequency wave energy, suggesting a large apparent stress and a sharp rise time, and consistent with the behaviour of many smaller shallow normal-faulting earthquakes. Hydrodynamic simulations based on a range of possible sources consistent with the above findings, including a compound rupture on two opposite-facing normal-faulting segments, are in satisfactory agreement with tsunami observations in Hawaii, where run-up reached 3 m, causing significant damage. This study emphasizes the need to include off-trench normal-faulting earthquake sources in global assessments of tsunami hazards emanating from the subduction of old and cold plates, whose total length of trenches exceed 20 000 km, even though only a handful of great such events are known with confidence in the instrumental record.
    Keywords: Seismology
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    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 90
    Publication Date: 2016-07-13
    Description: Pointwise error estimates for the first-order div least-squares (LS) finite element method for second-order elliptic partial differential equations are presented. Direct flux approximation is considered as an important advantage of the LS method. However, there are no known pointwise error estimates for the direct flux approximation. In this paper, we provide optimal pointwise estimates which show local dependence of the error at a point and weak dependence of the global norm. As an elementary consequence of these estimates, we provide an asymptotic error expansion inequality. The inequality has applications to superconvergence and a posteriori estimates.
    Print ISSN: 0272-4979
    Electronic ISSN: 1464-3642
    Topics: Mathematics
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  • 91
    Publication Date: 2016-07-13
    Description: The first-order and higher-order derivatives of a function can be viewed as the solutions of Volterra integral equations of the first kind. In this paper we propose a fast multiscale solver for the numerical solution of the Tikhonov regularization of the Volterra equations. In association with the special form of the kernels, the matrices resulting from the discretization by multiscale bases are sparse. Moreover, they can be truncated using proper strategies with only a minor loss of accuracy. In the best case, the number of nonzero entries of the truncated matrices is linear with respect to the dimensions of the matrices. The accuracy of the solution from the solver is analysed theoretically and verified by numerical experiments.
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  • 92
    Publication Date: 2016-07-13
    Description: The finite element method with $\mathscr {Q}_p$ elements is applied to a singularly perturbed convection–diffusion problem on an L-shaped domain. As an effect of corner singularities the exact solution is not $H^2$ -regular. Therefore, we combine a layer-adapted Shishkin mesh with a special grading adapted to the corner singularity. On such meshes we prove error estimates and estimates for the closeness error which explicitly show the influence of the grading parameter $\mu$ . Hence, $\mu$ can be chosen such that optimal error bounds are obtained. Thereby, it turns out that in the problem studied the influence of the corner singularity becomes small if the perturbation parameter $\varepsilon$ decreases. Moreover, we conduct numerical experiments that verify the theoretical results.
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  • 93
    Publication Date: 2016-07-13
    Description: Pták's method of nondiscrete induction is based on the idea that in the analysis of iterative processes one should aim at rates of convergence as functions rather than just numbers, because functions may give convergence estimates that are tight throughout the iteration rather than just asymptotically. In this paper we motivate and prove a theorem on nondiscrete induction, originally due to Potra and Pták, and we apply it to the Newton iterations for computing the matrix polar decomposition and the matrix square root. Our goal is to illustrate the application of the method of nondiscrete induction in the finite-dimensional numerical linear algebra context. We show the sharpness of the resulting convergence estimate analytically for the polar decomposition iteration and on some examples for the square root iteration. We also discuss some of the method's limitations and possible extensions.
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  • 94
    Publication Date: 2016-07-13
    Description: We consider the numerical solution, by a Petrov–Galerkin finite-element method, of a singularly perturbed reaction–diffusion differential equation posed on the unit square. In Lin & Stynes (2012, A balanced finite element method for singularly perturbed reaction-diffusion problems. SIAM J. Numer. Anal. , 50 , 2729–2743), it is argued that the natural energy norm, associated with a standard Galerkin approach, is not an appropriate setting for analysing such problems, and there they propose a method for which the natural norm is ‘balanced’. In the style of a first-order system least squares method, we extend the approach of Lin & Stynes (2012, A balanced finite element method for singularly perturbed reaction-diffusion problems. SIAM J. Numer. Anal. , 50 , 2729–2743) by introducing a constraint which simplifies the associated finite-element space and the method's analysis. We prove robust convergence in a balanced norm on a piecewise-uniform (Shishkin) mesh, and present supporting numerical results. Finally, we demonstrate how the resulting linear systems are solved optimally using multigrid methods.
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  • 95
    Publication Date: 2016-07-13
    Description: The construction of tensor-product surface patches with a family of Pythagorean-hodograph (PH) isoparametric curves is investigated. The simplest nontrivial instances, interpolating four prescribed patch boundary curves, involve degree $(5,4)$ tensor-product surface patches $\bf{x}(u,v)$ whose $v=\hbox {constant}$ isoparametric curves are all spatial PH quintics. It is shown that the construction can be reduced to solving a novel type of quadratic quaternion equation, in which the quaternion unknown and its conjugate exhibit left and right coefficients, while the quadratic term has a coefficient interposed between them. A closed-form solution for this type of equation is derived, and conditions for the existence of solutions are identified. The surfaces incorporate three residual scalar freedoms which can be exploited to improve the interior shape of the patch. The implementation of the method is illustrated through a selection of computed examples.
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  • 96
    Publication Date: 2016-07-13
    Description: Interior eigenvalues of bounded scattering objects can be rigorously characterized from multi-static and multi-frequency far field data, that is, from the behaviour of scattered waves far away from the object. This characterization, the so-called inside–outside duality, holds for various types of penetrable and impenetrable scatterers and is based on the behaviour of a particular eigenvalue of the far field operator. It naturally leads to a numerical algorithm for computing interior eigenvalues of a scatterer that does not require shape or physical properties of the scatterer as input. Since the nonlinear inverse problem to compute such interior eigenvalues from far field data is ill-posed, we propose a regularizing algorithm that is shown to converge as the noise level of the far field data tends to zero. We illustrate feasibility and accuracy of our algorithm by numerical experiments where we compute interior transmission eigenvalues and Robin eigenvalues of the Laplacian in three-dimensional domains from scattering data of these domains due to plane incident waves.
    Print ISSN: 0272-4979
    Electronic ISSN: 1464-3642
    Topics: Mathematics
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  • 97
    Publication Date: 2016-07-13
    Description: Regulated school days entail less free-living physical activity (PA) and outdoor stay, which may jeopardize the opportunities for cohesive moderate-to-vigorous physical activity (MVPA) and, by extension, children’s health. The role of outdoor stay during school time for pupils’ free-living PA vs. physical education (PE) and indoor stay was studied during one academic year in 196 pupils aged 7–14 years at four schools in mid-southern Sweden during five consecutive days each in September, March, and May. Actigraph GT3X+ Activity monitors were used. Predictors for PA during school stay were expressed as mean daily accelerometer counts and were measured per season, day, grade, gender, weather, and time outdoors. Overall, free-living PA outdoors generated the highest mean accelerometer counts for moderate and vigorous PA. Outdoor PA and PE, representing 23.7% of the total school time contributed to 50.4% of total mean accelerometer counts, and were the greatest contributors to moderate and vigorous PA. Age and weather impacted PA, with less PA in inclement weather and among older pupils. More time outdoors, at all seasons, would favorably increase school children’s chances of reaching recommended levels of PA.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 98
    Publication Date: 2016-07-13
    Description: Nuclear hazards, linked to both U.S. weapons programs and civilian nuclear power, pose substantial environment justice issues. Nuclear power plant (NPP) reactors produce low-level ionizing radiation, high level nuclear waste, and are subject to catastrophic contamination events. Justice concerns include plant locations and the large potentially exposed populations, as well as issues in siting, nuclear safety, and barriers to public participation. Other justice issues relate to extensive contamination in the U.S. nuclear weapons complex, and the mining and processing industries that have supported it. To approach the topic, first we discuss distributional justice issues of NPP sites in the U.S. and related procedural injustices in siting, operation, and emergency preparedness. Then we discuss justice concerns involving the U.S. nuclear weapons complex and the ways that uranium mining, processing, and weapons development have affected those living downwind, including a substantial American Indian population. Next we examine the problem of high-level nuclear waste and the risk implications of the lack of secure long-term storage. The handling and deposition of toxic nuclear wastes pose new transgenerational justice issues of unprecedented duration, in comparison to any other industry. Finally, we discuss the persistent risks of nuclear technologies and renewable energy alternatives.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 99
    Publication Date: 2016-07-13
    Description: Mothers’ instigation of complementary feeding before their infant reaches 6 months old risks shortening their breastfeeding duration, and high morbidity and mortality for their child. Complementary feeding practices require further investigation in Saudi Arabia. The present study aims to evaluate complementary feeding practices, and to establish which factors are associated with the early introduction of complementary feeding in the Saudi Arabian context. Cross-sectional research was conducted with 632 mothers of infants aged between 4 and 24 months attending five primary health care centers (PHCCs) between July and December 2015 in Saudi Arabia. Data on participants’ socio-demographic characteristics and complementary feeding practices were collected via structured questionnaires. A regression analysis identified the factors associated with the early introduction of solid foods, defined as before 17 weeks. 62.5% of the study’s infants received solid foods before reaching 17 weeks old. The maternal factors at higher risk of early introduction of solids were: younger age; Saudi nationality; shorter education; employment within 6 months post-birth; caesareans; not breastfeeding fully for six weeks post-birth, and living in low-income households. Complementary feeding prior to 6 months postpartum was common in Saudi Arabia. Public health interventions are needed to reduce early complementary feeding, focusing on mothers at highest risk of giving solids too early.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 100
    Publication Date: 2016-07-13
    Description: Introduction: Asthma is a multifactorial disease and a serious public health problem. Environmental factors and poverty are the main determinants of this disease. Objective: To describe the spatial and temporal distribution of asthma-related hospitalizations and identify the areas with the highest prevalence of and vulnerability to severe asthma in a major Brazilian city. Methods: An ecological study of hospitalizations for asthma from 2002 to 2012, in children and adolescents under 15 years of age, living in Belo Horizonte, Southeast Brazil. All events were geocoded by residence address using Hospital Information System data. The socioeconomic vulnerability of residence address was ranked using the Health Vulnerability Index. Raster surfaces were generated and time-series plots were constructed to determine spatial and time trends in the frequency of asthma-related hospitalizations, respectively. Results: Asthma-related hospitalization rates were highest in children aged 0–4 years and in boys. There was a decreasing trend in the number of asthma-related hospitalizations across the study period. Approximately 48% of all hospitalizations were children living in health vulnerable areas. Seasonal trends showed a hospitalization peak in March, April, and May, coinciding with the post-rainy period. Conclusion: Our findings suggest that social and environmental factors may be determinants of disparities in severe asthma.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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