ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Molecular Diversity Preservation International  (495,622)
  • Nature Publishing Group  (363,432)
  • Copernicus
  • American Association for the Advancement of Science (AAAS)
  • American Association of Petroleum Geologists (AAPG)
Collection
Keywords
Publisher
Years
  • 1
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science, American Association for the Advancement of Science (AAAS), 383(6685), pp. 884-890, ISSN: 0036-8075
    Publication Date: 2024-03-21
    Description: Much of our understanding of Cenozoic climate is based on the record of δ18O measured in benthic foraminifera. However, this measurement reflects a combined signal of global temperature and sea level, thus preventing a clear understanding of the interactions and feedbacks of the climate system in causing global temperature change. Our new reconstruction of temperature change over the past 4.5 million years includes two phases of long-term cooling, with the second phase of accelerated cooling during the Middle Pleistocene Transition (1.5 to 0.9 million years ago) being accompanied by a transition from dominant 41,000-year low-amplitude periodicity to dominant 100,000-year high-amplitude periodicity. Changes in the rates of long-term cooling and variability are consistent with changes in the carbon cycle driven initially by geologic processes, followed by additional changes in the Southern Ocean carbon cycle. 〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2024-04-17
    Description: TR17-08, a marine sedimentary core (14.6 m), was collected during 2017 from the Edisto Inlet (Ross Sea, Antarctica), a small fjord near Cape Hallett. The core is characterized by expanded laminated sedimentary sequences making it suitable for studying submillennial processes during the Early Holocene. By studying different well-known foraminifera species (Globocassidulina biora, G. subglobosa, Trifarina angulosa, Nonionella iridea, Epistominella exigua, Stainforthia feylingi, Miliammina arenacea, Paratrochammina bartrami and Portatrochammina antarctica), we were able to identify five different foraminiferal assemblages over the last ∼ 2000 years BP. Comparison with diatom assemblages and other geochemical proxies retrieved from nearby sediment cores in the Edisto Inlet (BAY05-20 and HLF17-1) made it possible to distinguish three different phases characterized by different environmental settings: (1) a seasonal phase (from 2012 to 1486 years BP) characterized by the dominance of calcareous species, indicating a seasonal opening of the inlet by more frequent events of melting of the sea-ice cover during the austral summer and, in general, a higher-productivity, more open and energetic environment; (2) a transitional phase (from 1486 to 696 years BP) during which the fjord experienced less extensive sea-ice melting, enhanced oxygen-poor conditions and carbonate dissolution conditions, indicated by the shifts from calcareous-dominated association to agglutinated-dominated association probably due to a freshwater input from the retreat of three local glaciers at the start of this period; and (3) a cooler phase (from 696 years BP to present) during which the sedimentation rate decreased and few to no foraminiferal specimens were present, indicating ephemeral openings or a more prolonged cover of the sea ice during the austral summer, affecting the nutrient supply and the sedimentation regime.
    Description: Published
    Description: 95–115
    Description: OSA2: Evoluzione climatica: effetti e loro mitigazione
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2024-04-04
    Description: Perturbations in stratospheric aerosol due to explosive volcanic eruptions are a primary contributor to natural climate variability. Observations of stratospheric aerosol are available for the past decades, and information from ice cores has been used to derive estimates of stratospheric sulfur injections and aerosol optical depth over the Holocene (approximately 10 000 BP to present) and into the last glacial period, extending back to 60 000 BP. Tephra records of past volcanism, compared to ice cores, are less complete but extend much further into the past. To support model studies of the potential impacts of explosive volcanism on climate variability across timescales, we present here an ensemble reconstruction of volcanic stratospheric sulfur injection (VSSI) over the last 140 000 years that is based primarily on terrestrial and marine tephra records. VSSI values are computed as a simple function of eruption magnitude based on VSSI estimates from ice cores and satellite observations for identified eruptions. To correct for the incompleteness of the tephra record, we include stochastically generated synthetic eruptions assuming a constant background eruption frequency from the ice core Holocene record. While the reconstruction often differs from ice core estimates for specific eruptions due to uncertainties in the data used and reconstruction method, it shows good agreement with an ice-core-based VSSI reconstruction in terms of millennial-scale cumulative VSSI variations over the Holocene. The PalVol reconstruction provides a new basis to test the contributions of forced vs. unforced natural variability to the spectrum of climate and the mechanisms leading to abrupt transitions in the palaeoclimate record with low- to high-complexity climate models. The PalVol volcanic forcing reconstruction is available at https://doi.org/10.26050/WDCC/PalVolv1 (Toohey and Schindlbeck-Belo, 2023).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2023-06-21
    Description: Abstract. Clouds are assumed to play an important role in the Arctic amplification process. This motivated a detailed investigation of cloud processes, including radiative and turbulent fluxes. Data from the aircraft campaign ACLOUD were analyzed with a focus on the mean and turbulent structure of the cloudy boundary layer over the Fram Strait marginal sea ice zone in late spring and early summer 2017. Vertical profiles of turbulence moments are presented from contrasting atmospheric boundary layers (ABLs) from 4 d. They differ by the magnitude of wind speed, boundary-layer height, stability, the strength of the cloud-top radiative cooling and the number of cloud layers. Turbulence statistics up to third-order moments are presented, which were obtained from horizontal-level flights and from slanted profiles. It is shown that both of these flight patterns complement each other and form a data set that resolves the vertical structure of the ABL turbulence well. The comparison of the 4 d shows that especially during weak wind, even in shallow Arctic ABLs with mixing ratios below 3 g kg-1, cloud-top cooling can serve as a main source of turbulent kinetic energy (TKE).Well-mixed ABLs are generated where TKE is increased and vertical velocity variance shows pronounced maxima in the cloud layer. Negative vertical velocity skewness points then to upside-down convection. Turbulent heat fluxes are directed upward in the cloud layer as a result of cold downdrafts. In two cases with single-layer stratocumulus, turbulent transport of heat flux and of temperature variance are both negative in the cloud layer, suggesting an important role of large eddies. In contrast, in a case with weak cloud-top cooling, these quantities are positive in the ABL due to the heating from the surface. Based on observations and results of a mixed-layer model it is shown that the maxima of turbulent fluxes are, however, smaller than the jump of the net terrestrial radiation flux across the upper part of a cloud due to the (i) shallowness of the mixed layer and (ii) the presence of a downward entrainment heat flux. The mixed-layer model also shows that the buoyancy production of TKE is substantially smaller in stratocumulus over the Arctic sea ice compared to subtropics due to a smaller surface moisture flux and smaller decrease in specific humidity (or even humidity inversions) right above the cloud top. In a case of strong wind, wind shear shapes the ABL turbulent structure, especially over rough sea ice, despite the presence of a strong cloud-top cooling. In the presence of mid-level clouds, cloud-top radiative cooling and thus also TKE in the lowermost cloud layer are strongly reduced, and the ABL turbulent structure becomes governed by stability, i.e., by the surface–air temperature difference and wind speed. A comparison of slightly unstable and weakly stable cases shows a strong reduction of TKE due to increased stability even though the absolute value of wind speed was similar. In summary, the presented study documents vertical profiles of the ABL turbulence with a high resolution in a wide range of conditions. It can serve as a basis for turbulence closure evaluation and process studies in Arctic clouds.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    Copernicus
    In:  EPIC3Atmospheric Chemistry and Physics, Copernicus, 23(5), pp. 3207-3232, ISSN: 1680-7316
    Publication Date: 2023-10-19
    Description: The presence of reactive bromine in polar regions is a widespread phenomenon that plays an important role in the photochemistry of the Arctic and Antarctic lower troposphere, including the destruction of ozone, the disturbance of radical cycles, and the oxidation of gaseous elemental mercury. The chemical mechanisms leading to the heterogeneous release of gaseous bromine compounds from saline surfaces are in principle well understood. There are, however, substantial uncertainties about the contribution of different potential sources to the release of reactive bromine, such as sea ice, brine, aerosols, and the snow surface, as well as about the seasonal and diurnal variation and the vertical distribution of reactive bromine. Here we use continuous long-term measurements of the vertical distribution of bromine monoxide (BrO) and aerosols at the two Antarctic sites Neumayer (NM) and Arrival Heights (AH), covering the periods of 2003–2021 and 2012–2021, respectively, to investigate how chemical and physical parameters affect the abundance of BrO. We find the strongest correlation between BrO and aerosol extinction (R=0.56 for NM and R=0.28 for AH during spring), suggesting that the heterogeneous release of Br2 from saline airborne particles (blowing snow and aerosols) is a dominant source for reactive bromine. Positive correlations between BrO and contact time of air masses, both with sea ice and the Antarctic ice sheet, suggest that reactive bromine is not only emitted by the sea ice surface but by the snowpack on the ice shelf and in the coastal regions of Antarctica. In addition, the open ocean appears to represent a source for reactive bromine during late summer and autumn when the sea ice extent is at its minimum. A source–receptor analysis based on back trajectories and sea ice maps shows that main source regions for BrO at NM are the Weddell Sea and the Filchner–Ronne Ice Shelf, as well as coastal polynyas where sea ice is newly formed. A strong morning peak in BrO frequently occurring during summer and that is particularly strong during autumn suggests a night-time build-up of Br2 by heterogeneous reaction of ozone on the saline snowpack in the vicinity of the measurement sites. We furthermore show that BrO can be sustained for at least 3 d while travelling across the Antarctic continent in the absence of any saline surfaces that could serve as a source for reactive bromine.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science Advances, American Association for the Advancement of Science (AAAS), 9(50), ISSN: 2375-2548
    Publication Date: 2023-12-18
    Description: Antarctic krill, crucial to the Southern Ocean ecosystem and a vital fisheries resource, is endangered by climate change. Identifying drivers of krill biomass is therefore essential for determining catch limits and designating protection zones. We present a modeling approach to pinpointing effects of sea surface temperature, ice cover, chlorophyll levels, climate indices, and intraspecific competition. Our study reveals that larval recruitment is driven by both competition among age classes and chlorophyll levels. In addition, while milder ice and temperature in spring and summer favor reproduction and early larval survival, both larvae and juveniles strongly benefit from heavier ice and colder temperatures in winter. We conclude that omitting top-down control of resources by krill is only acceptable for retrospective or single-year prognostic models that use field chlorophyll data but that incorporating intraspecific competition is essential for longer-term forecasts. Our findings can guide future krill modeling strategies, reinforcing the sustainability of this keystone species.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2023-08-08
    Description: 〈jats:p〉Arctic Ocean gateway fluxes play a crucial role in linking the Arctic with the global ocean and affecting climate and marine ecosystems. We reviewed past studies on Arctic–Subarctic ocean linkages and examined their changes and driving mechanisms. Our review highlights that radical changes occurred in the inflows and outflows of the Arctic Ocean during the 2010s. Specifically, the Pacific inflow temperature in the Bering Strait and Atlantic inflow temperature in the Fram Strait hit record highs, while the Pacific inflow salinity in the Bering Strait and Arctic outflow salinity in the Davis and Fram straits hit record lows. Both the ocean heat convergence from lower latitudes to the Arctic and the hydrological cycle connecting the Arctic with Subarctic seas were stronger in 2000–2020 than in 1980–2000. CMIP6 models project a continuing increase in poleward ocean heat convergence in the 21st century, mainly due to warming of inflow waters. They also predict an increase in freshwater input to the Arctic Ocean, with the largest increase in freshwater export expected to occur in the Fram Strait due to both increased ocean volume export and decreased salinity. Fram Strait sea ice volume export hit a record low in the 2010s and is projected to continue to decrease along with Arctic sea ice decline. We quantitatively attribute the variability of the volume, heat, and freshwater transports in the Arctic gateways to forcing within and outside the Arctic based on dedicated numerical simulations and emphasize the importance of both origins in driving the variability.〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2023-06-21
    Description: Springtime Arctic mixed-phase convection over open water in the Fram Strait as observed during the recent ACLOUD (Arctic CLoud Observations Using airborne measurements during polar Day) field campaign is simulated at turbulence-resolving resolutions. The first objective is to assess the skill of large-eddy simulation (LES) in reproducing the observed mixed-phase convection. The second goal is to then use the model to investigate how aerosol modulates the way in which turbulent mixing and clouds transform the low-level air mass. The focus lies on the low-level thermal structure and lapse rate, the heating efficiency of turbulent entrainment, and the low-level energy budget. A composite case is constructed based on data collected by two research aircraft on 18 June 2017. Simulations are evaluated against independent datasets, showing that the observed thermodynamic, cloudy, and turbulent states are well reproduced. Sensitivity tests on cloud condensation nuclei (CCN) concentration are then performed, covering a broad range between pristine polar and polluted continental values. We find a significant response in the resolved mixed-phase convection, which is in line with previous LES studies. An increased CCN substantially enhances the depth of convection and liquid cloud amount, accompanied by reduced surface precipitation. Initializing with the in situ CCN data yields the best agreement with the cloud and turbulence observations, a result that prioritizes its measurement during field campaigns for supporting high-resolution modeling efforts. A deeper analysis reveals that CCN significantly increases the efficiency of radiatively driven entrainment in warming the boundary layer. The marked strengthening of the thermal inversion plays a key role in this effect. The low-level heat budget shifts from surface driven to radiatively driven. This response is accompanied by a substantial reduction in the surface energy budget, featuring a weakened flow of solar radiation into the ocean. Results are interpreted in the context of air–sea interactions, air mass transformations, and climate feedbacks at high latitudes.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science Advances, American Association for the Advancement of Science (AAAS), 9(26), pp. eadf9696-eadf9696, ISSN: 2375-2548
    Publication Date: 2024-03-01
    Description: Dissolved iron (dFe) availability limits the uptake of atmospheric CO2 by the Southern Ocean (SO) biological pump. Hence, any change in bioavailable dFe in this region can directly influence climate. On the basis of Fe uptake experiments with Phaeocystis antarctica, we show that the range of dFe bioavailability in natural samples is wider (〈1 to ~200% compared to free inorganic Fe′) than previously thought, with higher bioavailability found near glacial sources. The degree of bioavailability varied regardless of in situ dFe concentration and depth, challenging the consensus that sole dFe concentrations can be used to predict Fe uptake in modeling studies. Further, our data suggest a disproportionately major role of biologically mediated ligands and encourage revisiting the role of humic substances in influencing marine Fe biogeochemical cycling in the SO. Last, we describe a linkage between in situ dFe bioavailability and isotopic signatures that, we anticipate, will stimulate future research.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Ocean-Land-Atmosphere Research, American Association for the Advancement of Science (AAAS), 2, ISSN: 2771-0378
    Publication Date: 2024-02-13
    Description: 〈jats:p〉Rapidly shrinking Arctic sea ice has had substantial impacts on the Earth system. Therefore, reliably estimating the Arctic sea-ice thickness (SIT) using a combination of available observations and numerical modeling is urgently needed. Here, for the first time, we assimilate the latest CryoSat-2 summer SIT data into a coupled ice-ocean model. In particular, an incremental analysis update scheme is implemented to overcome the discontinuity resulting from the combined assimilation of biweekly SIT and daily sea-ice concentration (SIC) data. Along with improved estimates of sea-ice volume, our SIT estimates corrected the overestimation of SIT produced by the reanalysis that assimilates only SIC in summer in areas where the sea ice is roughest and experiences strong deformation, e.g., around the Fram Strait and Greenland. This study suggests that the newly developed CryoSat-2 SIT product, when assimilated properly using our approach, has great potential for Arctic sea-ice simulation and prediction.〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science, American Association for the Advancement of Science (AAAS), 382(6677), pp. 1384-1389, ISSN: 0036-8075
    Publication Date: 2024-02-22
    Description: The marine-based West Antarctic Ice Sheet (WAIS) is considered vulnerable to irreversible collapse under future climate trajectories, and its tipping point may lie within the mitigated warming scenarios of 1.5° to 2°C of the United Nations Paris Agreement. Knowledge of ice loss during similarly warm past climates could resolve this uncertainty, including the Last Interglacial when global sea levels were 5 to 10 meters higher than today and global average temperatures were 0.5° to 1.5°C warmer than preindustrial levels. Using a panel of genome-wide, single-nucleotide polymorphisms of a circum-Antarctic octopus, we show persistent, historic signals of gene flow only possible with complete WAIS collapse. Our results provide the first empirical evidence that the tipping point of WAIS loss could be reached even under stringent climate mitigation scenarios.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2024-01-20
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science Advances, American Association for the Advancement of Science (AAAS), 9(8), pp. eabq4632-eabq4632, ISSN: 2375-2548
    Publication Date: 2024-04-03
    Description: 〈jats:p〉Comprehensive sampling of natural genetic diversity with metagenomics enables highly resolved insights into the interplay between ecology and evolution. However, resolving adaptive, neutral, or purifying processes of evolution from intrapopulation genomic variation remains a challenge, partly due to the sole reliance on gene sequences to interpret variants. Here, we describe an approach to analyze genetic variation in the context of predicted protein structures and apply it to a marine microbial population within the SAR11 subclade 1a.3.V, which dominates low-latitude surface oceans. Our analyses reveal a tight association between genetic variation and protein structure. In a central gene in nitrogen metabolism, we observe decreased occurrence of nonsynonymous variants from ligand-binding sites as a function of nitrate concentrations, revealing genetic targets of distinct evolutionary pressures maintained by nutrient availability. Our work yields insights into the governing principles of evolution and enables structure-aware investigations of microbial population genetics.〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science Advances, American Association for the Advancement of Science (AAAS), 9(44), pp. eadg2639-eadg2639, ISSN: 2375-2548
    Publication Date: 2024-04-24
    Description: Paleoceanographic reconstructions show that the strength of North Atlantic currents decreased during the Little Ice Age. In contrast, the role of ocean circulation in climate regulation during earlier historical epochs of the Common Era (C.E.) remains unclear. Here, we reconstruct sea surface temperature (SST) and salinity in the Caribbean Basin for the past 1700 years using the isotopic and elemental composition of planktic foraminifera tests. Centennial-scale SST and salinity variations in the Caribbean co-occur with (hydro)climate changes in the Northern Hemisphere and are linked to a North Atlantic SST forcing. Cold phases around 600, 800, and 1400 to 1600 C.E. are characterized by Caribbean salinification and Gulf of Mexico freshening that implies reductions in the strength of North Atlantic surface circulation. We suggest that the associated changes in the meridional salt advection contributed to the historical climate variability of the C.E.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2024-04-29
    Description: Stable water isotopologues of snow, firn and ice cores provide valuable information on past climate variations. Yet single profiles are generally not suitable for robust climate reconstructions. Stratigraphic noise, introduced by the irregular deposition, wind-driven erosion and redistribution of snow, impacts the utility of high-resolution isotope records, especially in low-Accumulation areas. However, it is currently unknown how stratigraphic noise differs across the East Antarctic Plateau and how it is affected by local environmental conditions. Here, we assess the amount and structure of stratigraphic noise at seven sites along a 120 km transect on the plateau of Dronning Maud Land, East Antarctica. Replicated oxygen isotope records of 1 m length were used to estimate signal-To-noise ratios as a measure of stratigraphic noise at sites characterised by different accumulation rates (43-64 mm w.e. a-1), snow surface roughnesses and slope inclinations. While we found a high level of stratigraphic noise at all sites, there was also considerable variation between sites. At sastrugi-dominated sites, greater stratigraphic noise coincided with stronger surface roughnesses, steeper slopes and lower accumulation rates, probably related to increased wind speeds. These results provide a first step to modelling stratigraphic noise and might guide site selection and sampling strategies for future expeditions to improve high-resolution climate reconstructions from low-Accumulation regions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    facet.materialart.
    Unknown
    Nature Publishing Group
    In:  EPIC3Nature Climate Change, Nature Publishing Group, 12(3), pp. 249-255
    Publication Date: 2022-06-20
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2022-10-24
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2022-06-29
    Description: We developed a new version of the Alfred Wegener Institute Climate Model (AWI-CM3), which has higher skills in representing the observed climatology and better computational efficiency than its predecessors. Its ocean component FESOM2 has the multi-resolution functionality typical for unstructured-mesh models while still featuring a scalability and efficiency similar to regular-grid models. The atmospheric component OpenIFS (CY43R3) enables the use of latest developments in the numerical weather prediction community in climate sciences. In this paper we describe the coupling of the model components and evaluate the model performance on a variable resolution (25–125 km) ocean mesh and a 61 km atmosphere grid, which serves as a reference and starting point for other on-going research activities with AWI-CM3. This includes the exploration of high and variable resolution, the development of a full Earth System Model as well as the creation of a new sea ice prediction system. At this early development stage and with the given coarse to medium resolutions, the model already features above CMIP6-average skills in representing the climatology and competitive model throughput. Finally we identify remaining biases and suggest further improvements to be made to the model.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2022-09-23
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    Copernicus
    In:  EPIC3On the true and the perceived minor interactions of dissolved phosphate and dissolved sulphate and some other constituents with the Alkalinity of oceanic seawater, EGUsphere [preprint], Copernicus
    Publication Date: 2022-08-08
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Publication Date: 2022-08-11
    Description: The methanogenic degradation of oil hydrocarbons can proceed through syntrophic partnerships of hydrocarbon-degrading bacteria and methanogenic archaea1,2,3. However, recent culture-independent studies have suggested that the archaeon ‘Candidatus Methanoliparum’ alone can combine the degradation of long-chain alkanes with methanogenesis4,5. Here we cultured Ca. Methanoliparum from a subsurface oil reservoir. Molecular analyses revealed that Ca. Methanoliparum contains and overexpresses genes encoding alkyl-coenzyme M reductases and methyl-coenzyme M reductases, the marker genes for archaeal multicarbon alkane and methane metabolism. Incubation experiments with different substrates and mass spectrometric detection of coenzyme-M-bound intermediates confirm that Ca. Methanoliparum thrives not only on a variety of long-chain alkanes, but also on n-alkylcyclohexanes and n-alkylbenzenes with long n-alkyl (C≥13) moieties. By contrast, short-chain alkanes (such as ethane to octane) or aromatics with short alkyl chains (C≤12) were not consumed. The wide distribution of Ca. Methanoliparum4,5,6 in oil-rich environments indicates that this alkylotrophic methanogen may have a crucial role in the transformation of hydrocarbons into methane.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2022-10-31
    Description: The statistical properties of seismicity are known to be affected by several factors such as the rheological parameters of rocks. We analysed the earthquake double-couple as a function of the faulting type. Here we show that it impacts the moment tensors of earthquakes: thrust- faulting events are characterized by higher double-couple components with respect to strike- slip- and normal-faulting earthquakes. Our results are coherent with the stress dependence of the scaling exponent of the Gutenberg-Richter law, which is anticorrelated to the double- couple. We suggest that the structural and tectonic control of seismicity may have its origin in the complexity of the seismogenic source marked by the width of the cataclastic damage zone and by the slip of different fault planes during the same seismic event; the sharper and concentrated the slip as along faults, the higher the double-couple. This phenomenon may introduce bias in magnitude estimation, with possible impact on seismic forecasting.
    Description: Published
    Description: 258
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: double couple ; damage zone ; different fault type ; seismicity ; tectonics ; fault type ; seismicity ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    In:  EPIC3Science, American Association for the Advancement of Science (AAAS), 378(6617), pp. 230-230, ISSN: 0036-8075
    Publication Date: 2023-05-10
    Description: 〈jats:p〉 Next week, the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) convenes in Hobart, Tasmania, to examine the state of marine life in the Southern Ocean. As part of the Antarctic Treaty System, this convention entered into force in 1982, and its focus on the region’s environmental integrity has never been more important, given the increasing effects of climate change and commercial fishing. An important focus over the past 40 years has been Antarctic krill, 〈jats:italic〉Euphausia superba〈/jats:italic〉 (hereafter krill), a keystone species that helps to hold this marine ecosystem together. Climate and fishing stresses should prompt the CCAMLR to address whether management of krill fishing is at a level that protects the Southern Ocean from losing its overall balance of marine life and the oceanic processes that regulate global climate. 〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2022-11-14
    Description: Changes in Southern Ocean export production have broad biogeochemical and climatic implications. Specifically, iron fertilization likely increased subantarctic nutrient utilization and enhanced the efficiency of the biological pump during glacials. However, past export production in the subantarctic Southeast Pacific is poorly documented, and its connection to Fe fertilization, potentially related to Patagonian Ice Sheet dynamics is unknown. We report on biological productivity changes over the past 400 ka, based on a combination of 230Thxs-normalized and stratigraphy-based mass accumulation rates of biogenic barium, organic carbon, biogenic opal, and calcium carbonate as indicators of paleo-export production in a sediment core upstream of the Drake Passage. In addition, we use fluxes of iron and lithogenic material as proxies for terrigenous matter, and thus potential micronutrient supply. Stratigraphy-based mass accumulation rates are strongly influenced by bottom-current dynamics, which result in variable sediment focussing or winnowing at our site. Carbonate is virtually absent in the core, except during peak interglacial intervals of the Holocene, and Marine Isotope Stages (MIS) 5 and 11, likely caused by transient decreases in carbonate dissolution. All other proxies suggest that export production increased during most glacial periods, coinciding with high iron fluxes. Such augmented glacial iron fluxes at the core site were most likely derived from glaciogenic input from the Patagonian Ice Sheet promoting the growth of phytoplankton. Additionally, glacial export production peaks are also consistent with northward shifts of the Subantarctic and Polar Fronts, which positioned our site south of the Subantarctic Front and closer to silicic acid-rich waters of the Polar Frontal Zone, as well as a with a decrease in the diatom utilization of Si relative to nitrate under Fe-replete conditions. However, glacial export production near the Drake Passage was lower than in the Atlantic and Indian sectors of the Southern Ocean, which may relate to complete consumption of silicic acid in the study area. Our results underline the importance of micro-nutrient fertilization through lateral terrigenous input from South America rather than aeolian transport, and exemplify the role of frontal shifts and nutrient limitation for past productivity changes in the Pacific entrance to the Drake Passage.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Publication Date: 2024-01-31
    Description: Arctic river deltas and deltaic near-shore zones represent important land–ocean transition zones influencing sediment dynamics and nutrient fluxes from permafrost-affected terrestrial ecosystems into the coastal Arctic Ocean. To accurately model fluvial carbon and freshwater export from rapidly changing river catchments as well as assess impacts of future change on the Arctic shelf and coastal ecosystems, we need to understand the sea floor characteristics and topographic variety of the coastal zones. To date, digital bathymetrical data from the poorly accessible, shallow, and large areas of the eastern Siberian Arctic shelves are sparse. We have digitized bathymetrical information for nearly 75 000 locations from large-scale (1:25 000–1:500 000) current and historical nautical maps of the Lena Delta and the Kolyma Gulf region in northeastern Siberia. We present the first detailed and seamless digital models of coastal zone bathymetry for both delta and gulf regions in 50 and 200 m spatial resolution. We validated the resulting bathymetry layers using a combination of our own water depth measurements and a collection of available depth measurements, which showed a strong correlation (r〉0.9). Our bathymetrical models will serve as an input for a high-resolution coupled hydrodynamic–ecosystem model to better quantify fluvial and coastal carbon fluxes to the Arctic Ocean, but they may be useful for a range of other studies related to Arctic delta and near-shore dynamics such as modeling of submarine permafrost, near-shore sea ice, or shelf sediment transport. The new digital high-resolution bathymetry products are available on the PANGAEA data set repository for the Lena Delta (https://doi.org/10.1594/PANGAEA.934045; Fuchs et al., 2021a) and Kolyma Gulf region (https://doi.org/10.1594/PANGAEA.934049; Fuchs et al., 2021b), respectively. Likewise, the depth validation data are available on PANGAEA as well (https://doi.org/10.1594/PANGAEA.933187; Fuchs et al., 2021c).
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Publication Date: 2024-04-19
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2024-02-07
    Description: The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing regular compilations of surface-to-bottom ocean biogeochemical bottle data, with an emphasis on seawater inorganic carbon chemistry and related variables determined through chemical analysis of seawater samples. GLODAPv2.2022 is an update of the previous version, GLODAPv2.2021 (Lauvset et al., 2021). The major changes are as follows: data from 96 new cruises were added, data coverage was extended until 2021, and for the first time we performed secondary quality control on all sulphur hexafluoride (SF6) data. In addition, a number of changes were made to data included in GLODAPv2.2021. These changes affect specifically the SF6 data, which are now subjected to secondary quality control, and carbon data measured onboard the RV Knorr in the Indian Ocean in 1994–1995 which are now adjusted using CRM measurements made at the time. GLODAPv2.2022 includes measurements from almost 1.4 million water samples from the global oceans collected on 1085 cruises. The data for the now 13 GLODAP core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, CCl4, and SF6) have undergone extensive quality control with a focus on systematic evaluation of bias. The data are available in two formats: (i) as submitted by the data originator but converted to World Ocean Circulation Experiment (WOCE) exchange format and (ii) as a merged data product with adjustments applied to minimize bias. For the present annual update, adjustments for the 96 new cruises were derived by comparing those data with the data from the 989 quality controlled cruises in the GLODAPv2.2021 data product using crossover analysis. SF6 data from all cruises were evaluated by comparison with CFC-12 data measured on the same cruises. For nutrients and ocean carbon dioxide (CO2) chemistry comparisons to estimates based on empirical algorithms provided additional context for adjustment decisions. The adjustments that we applied are intended to remove potential biases from errors related to measurement, calibration, and data handling practices without removing known or likely time trends or variations in the variables evaluated. The compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 μmol kg-1 in dissolved inorganic carbon, 4 μmol kg-1 in total alkalinity, 0.01–0.02 in pH (depending on region), and 5 % in the halogenated transient tracers. The other variables included in the compilation, such as isotopic tracers and discrete CO2 fugacity (fCO2), were not subjected to bias comparison or adjustments.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Publication Date: 2021-06-07
    Description: The diagnosis of the conservation state of monumental structures from constraints to the spatial distribution of their physical properties on shallow and inner materials represents one of the key objectives in the application of non-invasive techniques. In situ, CRP and 3D ultrasonic tomography can provide an effective coverage of stone materials in space and time. The intrinsic characteristics of the materials that make up a monumental structure and affect the two properties (i.e., reflectivity, longitudinal velocity) through the above methods substantially differ. Consequently, the content of their information is mainly complementary rather than redundant. In this study we present the integrated application of different non-destructive techniques i.e., Close Range Photogrammetry (CRP), and low frequency (24 KHz) ultrasonic tomography complemented by petrographycal analysis based essentially on Optical Microscopy (OM). This integrated methodology has been applied to a Carrara marble column of the Basilica of San Saturnino, in Byzantine-Proto-Romanesque style, which is part of the Paleo Christian complex of the V-VI century. This complex also includes the adjacent Christian necropolis in the square of San Cosimo in the city of Cagliari, Sardinia, Italy. The column under study is made of bare material dating back probably to the first century A.D., it was subjected to various traumas due to disassembly and transport to the site, including damage caused by the close blast of a WWII fragmentation bomb. High resolution 3D modelling of the studied artifact was computed starting from the integration of proximal sensing techniques such as CRP based on Structure from Motion (SfM), with which information about the geometrical anomalies and reflectivity of the investigated marble column surface was obtained. On the other hand, the inner parts of the studied body were successfully inspected in a non-invasive way by computing the velocity pattern of the ultrasonic signal through the investigated materials using 3D ultrasonic tomography. This technique gives information on the elastic properties of the material related with mechanical properties and a number of factors, such as presence of fractures, voids, and flaws. Extracting information on such factors from the elastic wave velocity using 3D tomography provides a non-invasive approach to analyse the property changes of the inner material of the ancient column. The integrated application of in situ CRP and ultrasonic techniques provides a full 3D high resolution model of the investigated artifact. This model enhanced by the knowledge of the petrographic characteristics of the materials, improves the diagnostic process and affords reliable information on the state of conservation of the materials used in the construction processes of the studied monumental structure. The integrated use of the non-destructive techniques described above also provides suitable data for a possible restoration and future preservation.
    Description: Copernicus
    Description: Published
    Description: On line
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Keywords: Cultural Heritage ; Monumental Structures ; Non-Destructive Testing ; Close Range Photogrammetry ; 3D Ultrasonic Tomography ; High resolution 3D modelling ; Restoration ; Conservation ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2021-07-23
    Description: Originating from the boreal forest and often transported over large distances, driftwood characterises many Arctic coastlines. Here we present a combined assessment of radiocarbon (14C) and dendrochronological (ring width) age estimates of driftwood samples to constrain the progradation of two Holocene beach-ridge systems near the Lena Delta in the Siberian Arctic (Laptev Sea). Our data show that the 14C ages obtained on syndepositional driftwood from beach deposits yield surprisingly coherent chronologies for the coastal evolution of the field sites. The dendrochronological analysis of wood from modern driftlines revealed the origin and recent delivery of the wood from the Lena River catchments. This finding suggests that the duration transport lies within the uncertainty of state-of-the-art 14C dating and thus substantiates the validity of age indication obtained from driftwood. This observation will help to better understand changes in similar coastal environments, and to improve our knowledge about the response of coastal systems to past climate and sea-level changes.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2021-02-03
    Description: The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today; in the Atlantic basin, deep waters of Southern Ocean origin increased in volume while above them the core of the North Atlantic Deep Water (NADW) shoaled. An absence of evidence on the origin of this phenomenon means that the sequence of events leading to global glacial conditions remains unclear. Here we present multi-proxy evidence showing that northward shifts in Antarctic iceberg melt in the Indian–Atlantic Southern Ocean (0–50°E) systematically preceded deep-water mass reorganizations by one to two thousand years during Pleistocene-era glaciations. With the aid of iceberg-trajectory model experiments, we demonstrate that such a shift in iceberg trajectories during glacial periods can result in a considerable redistribution of freshwater in the Southern Ocean. We suggest that this, in concert with increased sea-ice cover, enabled positive buoyancy anomalies to ‘escape’ into the upper limb of the AMOC, providing a teleconnection between surface Southern Ocean conditions and the formation of NADW. The magnitude and pacing of this mechanism evolved substantially across the mid-Pleistocene transition, and the coeval increase in magnitude of the ‘southern escape’ and deep circulation perturbations implicate this mechanism as a key feedback in the transition to the ‘100-kyr world’, in which glacial–interglacial cycles occur at roughly 100,000-year periods.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2021-07-05
    Description: Earth system and climate modelling involves the simulation of processes on a wide range of scales and within and across various compartments of the Earth system. In practice, component models are often developed independently by different research groups, adapted by others to their special interests and then combined using a dedicated coupling software. This procedure not only leads to a strongly growing number of available versions of model components and coupled setups but also to model- and high-performance computing (HPC)-system-dependent ways of obtaining, configuring, building and operating them. Therefore, implementing these Earth system models (ESMs) can be challenging and extremely time consuming, especially for less experienced modellers or scientists aiming to use different ESMs as in the case of intercomparison projects. To assist researchers and modellers by reducing avoidable complexity, we developed the ESM-Tools software, which provides a standard way for downloading, configuring, compiling, running and monitoring different models on a variety of HPC systems. It should be noted that ESM-Tools is not a coupling software itself but a workflow and infrastructure management tool to provide access to increase usability of already existing components and coupled setups. As coupled ESMs are technically the more challenging tasks, we will focus on coupled setups, always implying that stand-alone models can benefit in the same way. With ESM-Tools, the user is only required to provide a short script consisting of only the experiment-specific definitions, while the software executes all the phases of a simulation in the correct order. The software, which is well documented and easy to install and use, currently supports four ocean models, three atmosphere models, two biogeochemistry models, an ice sheet model, an isostatic adjustment model, a hydrology model and a land-surface model. Compared to previous versions, ESM-Tools has lately been entirely recoded in a high-level programming language (Python) and provides researchers with an even more user-friendly interface for Earth system modelling. ESM-Tools was developed within the framework of the Advanced Earth System Model Capacity project, supported by the Helmholtz Association.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    facet.materialart.
    Unknown
    Copernicus
    In:  EPIC3Geochemical evidence of a floating Arctic ice sheet and underlying freshwater in the Arctic Mediterranean in glacial periods, EGU General Assembly 2021, Copernicus, pp. EGU21-12910
    Publication Date: 2021-05-01
    Description: Numerous studies have addressed the possible existence of large floating ice sheets in the glacial Arctic Ocean from theoretical, modelling, or seafloor morphology perspectives. Here, we add evidence from the sediment record that support the existence of such freshwater ice caps in certain intervals, and we discuss their implications for possible non-linear and rapid behaviour of such a system in the high latitudes. We present sedimentary activities of 230Th together with 234U/238U ratios, the concentrations of manganese, sulphur and calcium in the context of lithological information and records of microfossils and their isotope composition. New analyses (PS51/038, PS72/396) and a re-analysis of existing marine sediment records (PS1533, PS1235, PS2185, PS2200, amongst others) in view of the naturally occurring radionuclide 230Thex and, where available, 10Be from the Arctic Ocean and the Nordic Seas reveal the widespread occurrence of intervals with a specific geochemical signature. The pattern of these parameters in a pan-Arctic view can best be explained when assuming the repeated presence of freshwater in frozen and liquid form across large parts of the Arctic Ocean and the Nordic Seas. Based on the sedimentary evidence and known environmental constraints at the time, we develop a glacial scenario that explains how these ice sheets, together with eustatic sea-level changes, may have affected the past oceanography of the Arctic Ocean in a fundamental way that must have led to a drastic and non-linear response to external forcing. This concept offers a possibility to explain and to some extent reconcile contrasting age models for the Late Pleistocene in the Arctic Ocean. Our view, if adopted, offers a coherent dating approach across the Arctic Ocean and the Nordic Seas, linked to events outside the Arctic.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2021-07-01
    Description: The modeling of paleoclimate, using physically based tools, is increasingly seen as a strong out-of-sample test of the models that are used for the projection of future climate changes. New to the Coupled Model Intercomparison Project (CMIP6) is the Tier 1 Last Interglacial experiment for 127 000 years ago (lig127k), designed to address the climate responses to stronger orbital forcing than the midHolocene experiment, using the same state-of-the-art models as for the future and following a common experimental protocol. Here we present a first analysis of a multi-model ensemble of 17 climate models, all of which have completed the CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. The equilibrium climate sensitivity (ECS) of these models varies from 1.8 to 5.6 ∘C. The seasonal character of the insolation anomalies results in strong summer warming over the Northern Hemisphere continents in the lig127k ensemble as compared to the CMIP6 piControl and much-reduced minimum sea ice in the Arctic. The multi-model results indicate enhanced summer monsoonal precipitation in the Northern Hemisphere and reductions in the Southern Hemisphere. These responses are greater in the lig127k than the CMIP6 midHolocene simulations as expected from the larger insolation anomalies at 127 than 6 ka. New synthesis for surface temperature and precipitation, targeted for 127 ka, have been developed for comparison to the multi-model ensemble. The lig127k model ensemble and data reconstructions are in good agreement for summer temperature anomalies over Canada, Scandinavia, and the North Atlantic and for precipitation over the Northern Hemisphere continents. The model–data comparisons and mismatches point to further study of the sensitivity of the simulations to uncertainties in the boundary conditions and of the uncertainties and sparse coverage in current proxy reconstructions. The CMIP6–Paleoclimate Modeling Intercomparison Project (PMIP4) lig127k simulations, in combination with the proxy record, improve our confidence in future projections of monsoons, surface temperature, and Arctic sea ice, thus providing a key target for model evaluation and optimization.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2021-09-20
    Description: In order to investigate the impact of spatial resolution on the discrepancy between simulated δ18O and observed δ18O in Greenland ice cores, regional climate simulations are performed with the isotope-enabled regional climate model (RCM) COSMO_iso. For this purpose, isotope-enabled general circulation model (GCM) simulations with the ECHAM5-wiso general circulation model (GCM) under present-day conditions and the MPI-ESM-wiso GCM under mid-Holocene conditions are dynamically downscaled with COSMO_iso for the Arctic region. The capability of COSMO_iso to reproduce observed isotopic ratios in Greenland ice cores for these two periods is investigated by comparing the simulation results to measured δ18O ratios from snow pit samples, Global Network of Isotopes in Precipitation (GNIP) stations and ice cores. To our knowledge, this is the first time that a mid-Holocene isotope-enabled RCM simulation is performed for the Arctic region. Under present-day conditions, a dynamical downscaling of ECHAM5-wiso (1.1◦ × 1.1◦) with COSMO_iso to a spatial resolution of 50km improves the agreement with the measured δ18O ratios for 14 of 19 observational data sets. A further increase in the spatial resolution to 7km does not yield substantial improvements except for the coastal areas with its complex terrain. For the mid-Holocene, a fully coupled MPI-ESM-wiso time slice simulation is downscaled with COSMO_iso to a spatial resolution of 50km. In the mid-Holocene, MPI-ESM-wiso already agrees well with observations in Greenland and a downscaling with COSMO_iso does not further improve the model–data agreement. Despite this lack of improvement in model biases, the study shows that in both periods, observed δ18O values at measurement sites constitute isotope ratios which are mainly within the subgrid-scale variability of the global ECHAM5-wiso and MPI-ESM-wiso simulation results. The correct δ18O ratios are consequently not resolved in the GCM simulation results and need to be extracted by a refinement with an RCM. In this context, the RCM simulations provide a spatial δ18O distribution by which the effects of local uncertainties can be taken into account in the comparison between point measurements and model outputs. Thus, an isotope-enabled GCM–RCM model chain with realistically implemented fractionating processes constitutes a useful supplement to reconstruct regional paleo-climate conditions during the mid-Holocene in Greenland. Such model chains might also be applied to reveal the full potential of GCMs in other regions and climate periods, in which large deviations relative to observed isotope ratios are simulated.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2021-09-20
    Description: Proxy climate records are an invaluable source of information about the earth’s climate prior to the instrumental record. The temporal- and spatial-coverage of records continues to increase, however, these records of past climate are associated with significant uncertainties due to non-climate processes that influence the recorded and measured proxy values. Generally, these uncertainties are timescale-dependent and correlated in time. Accounting for structure in the errors is essential to providing realistic error estimates for smoothed or stacked records, detection of anomalies and identifying trends, but this structure is seldom accounted for. In the first of these companion articles we outlined a theoretical framework for handling proxy uncertainties by deriving the power spectrum of proxy error components from which it is possible to obtain timescale-dependent error estimates. Here in part II, we demonstrate the practical application of this theoretical framework using the example of marine sediment cores. We consider how to obtain estimates for the required parameters and give examples of the application of this approach for typical marine sediment proxy records. Our new approach of estimating and providing timescale-dependent proxy errors overcomes the limitations of simplistic single value error estimates. We aim to provide the conceptual basis for a more quantitative use of paleo-records for applications such as model-data comparison, regional and global synthesis of past climate states and data assimilation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2021-09-06
    Description: The mid-Pliocene warm period (mPWP; ∼3.2 million years ago) is seen as the most recent time period characterized by a warm climate state, with similar to modern geography and ∼400 ppmv atmospheric CO2 concentration, and is therefore often considered an interesting analogue for near-future climate projections. Paleoenvironmental reconstructions indicate higher surface temperatures, decreasing tropical deserts, and a more humid climate in West Africa characterized by a strengthened West African Monsoon (WAM). Using model results from the second phase of the Pliocene Modelling Intercomparison Project (PlioMIP2) ensemble, we analyse changes of the WAM rainfall during the mPWP by comparing them with the control simulations for the pre-industrial period. The ensemble shows a robust increase in the summer rainfall over West Africa and the Sahara region, with an average increase of 2.5 mm/d, contrasted by a rainfall decrease over the equatorial Atlantic. An anomalous warming of the Sahara and deepening of the Saharan Heat Low, seen in 〉90 % of the models, leads to a strengthening of the WAM and an increased monsoonal flow into the continent. A similar warming of the Sahara is seen in future projections using both phase 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5). Though previous studies of future projections indicate a west–east drying–wetting contrast over the Sahel, PlioMIP2 simulations indicate a uniform rainfall increase in that region in warm climates characterized by increasing greenhouse gas forcing. We note that this effect will further depend on the long-term response of the vegetation to the CO2 forcing.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2022-01-10
    Description: The mid-Pliocene warm period (3.264–3.025 Ma) is the most recent geological period during which atmospheric CO2 levels were similar to recent historical values (∼400 ppm). Several proxy reconstructions for the mid-Pliocene show highly reduced zonal sea surface temperature (SST) gradients in the tropical Pacific Ocean, indicating an El Niño-like mean state. However, past modelling studies do not show these highly reduced gradients. Efforts to understand mid-Pliocene climate dynamics have led to the Pliocene Model Intercomparison Project (PlioMIP). Results from the first phase (PlioMIP1) showed clear El Niño variability (albeit significantly reduced) and did not show the greatly reduced time-mean zonal SST gradient suggested by some of the proxies. In this work, we study El Niño–Southern Oscillation (ENSO) variability in the PlioMIP2 ensemble, which consists of additional global coupled climate models and updated boundary conditions compared to PlioMIP1. We quantify ENSO amplitude, period, spatial structure and “flavour”, as well as the tropical Pacific annual mean state in mid-Pliocene and pre-industrial simulations. Results show a reduced ENSO amplitude in the model-ensemble mean (−24 %) with respect to the pre-industrial, with 15 out of 17 individual models showing such a reduction. Furthermore, the spectral power of this variability considerably decreases in the 3–4-year band. The spatial structure of the dominant empirical orthogonal function shows no particular change in the patterns of tropical Pacific variability in the model-ensemble mean, compared to the pre-industrial. Although the time-mean zonal SST gradient in the equatorial Pacific decreases for 14 out of 17 models (0.2 ∘C reduction in the ensemble mean), there does not seem to be a correlation with the decrease in ENSO amplitude. The models showing the most “El Niño-like” mean state changes show a similar ENSO amplitude to that in the pre-industrial reference, while models showing more “La Niña-like” mean state changes generally show a large reduction in ENSO variability. The PlioMIP2 results show a reasonable agreement with both time-mean proxies indicating a reduced zonal SST gradient and reconstructions indicating a reduced, or similar, ENSO variability.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2022-01-10
    Description: The mid-Pliocene (∼3 Ma) is one of the most recent warm periods with high CO2 concentrations in the atmosphere and resulting high temperatures, and it is often cited as an analog for near-term future climate change. Here, we apply a moisture budget analysis to investigate the response of the large-scale hydrological cycle at low latitudes within a 13-model ensemble from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The results show that increased atmospheric moisture content within the mid-Pliocene ensemble (due to the thermodynamic effect) results in wetter conditions over the deep tropics, i.e., the Pacific intertropical convergence zone (ITCZ) and the Maritime Continent, and drier conditions over the subtropics. Note that the dynamic effect plays a more important role than the thermodynamic effect in regional precipitation minus evaporation (PmE) changes (i.e., northward ITCZ shift and wetter northern Indian Ocean). The thermodynamic effect is offset to some extent by a dynamic effect involving a northward shift of the Hadley circulation that dries the deep tropics and moistens the subtropics in the Northern Hemisphere (i.e., the subtropical Pacific). From the perspective of Earth's energy budget, the enhanced southward cross-equatorial atmospheric transport (0.22 PW), induced by the hemispheric asymmetries of the atmospheric energy, favors an approximately 1∘ northward shift of the ITCZ. The shift of the ITCZ reorganizes atmospheric circulation, favoring a northward shift of the Hadley circulation. In addition, the Walker circulation consistently shifts westward within PlioMIP2 models, leading to wetter conditions over the northern Indian Ocean. The PlioMIP2 ensemble highlights that an imbalance of interhemispheric atmospheric energy during the mid-Pliocene could have led to changes in the dynamic effect, offsetting the thermodynamic effect and, hence, altering mid-Pliocene hydroclimate.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2021-12-15
    Description: Due to its dryness, the subtropical free troposphere plays a critical role in the radiative balance of the Earth's climate system. But the complex interactions of the dynamical and physical processes controlling the variability in the moisture budget of this sensitive region of the subtropical atmosphere are still not fully understood. Stable water isotopes can provide important information about several of the latter processes, namely subsidence drying, turbulent mixing, and dry and moist convective moistening. In this study, we use high-resolution simulations of the isotope-enabled version of the regional weather and climate prediction model of the Consortium for Small-Scale Modelling (COSMOiso) to investigate predominant moisture transport pathways in the Canary Islands region in the eastern subtropical North Atlantic. Comparison of the simulated isotope signals with multi-platform isotope observations (aircraft, ground- and space-based remote sensing) from a field campaign in summer 2013 shows that COSMOiso can reproduce the observed variability of stable water vapour isotopes on timescales of hours to days, thus allowing us to study the mechanisms that control the subtropical free-tropospheric humidity. Changes in isotopic signals along backward trajectories from the Canary Islands region reveal the physical processes behind the synoptic-scale isotope variability. We identify four predominant moisture transport pathways of mid-tropospheric air, each with distinct isotopic signatures: - air parcels originating from the convective boundary layer of the Saharan heat low (SHL) – these are characterised by a homogeneous isotopic composition with a particularly high δD (median mid-tropospheric δD=−122‰), which results from dry convective mixing of low-level moisture of diverse origin advected into the SHL; - air parcels originating from the free troposphere above the SHL – although experiencing the largest changes in humidity and δD during their subsidence over West Africa, these air parcels typically have lower δD values (median δD=−148‰) than air parcels originating from the boundary layer of the SHL; - air parcels originating from outside the SHL region, typically descending from tropical upper levels south of the SHL, which are often affected by moist convective injections from mesoscale convective systems in the Sahel – their isotopic composition is much less enriched in heavy isotopes (median δD=−175‰) than those from the SHL region; - air parcels subsiding from the upper-level extratropical North Atlantic – this pathway leads to the driest and most depleted conditions (median δD=−255‰) in the middle troposphere near the Canary Islands. The alternation of these transport pathways explains the observed high variability in humidity and δD on synoptic timescales to a large degree. We further show that the four different transport pathways are related to specific large-scale flow conditions. In particular, distinct differences in the location of the North African mid-level anticyclone and of extratropical Rossby wave patterns occur between the four transport pathways. Overall, this study demonstrates that the adopted Lagrangian isotope perspective enhances our understanding of air mass transport and mixing and offers a sound interpretation of the free-tropospheric variability of specific humidity and isotope composition on timescales of hours to days in contrasting atmospheric conditions over the eastern subtropical North Atlantic.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2021-12-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2021-10-20
    Description: Coastal sands are biocatalytic filters for dissolved and particulate organic matter of marine and terrestrial origin, thus, acting as centers of organic matter transformation. At high temporal resolution, we accessed the variability of benthic bacterial communities over two annual cycles at Helgoland (North Sea), and compared it with seasonality of communities in Isfjorden (Svalbard, 78°N) sediments, where primary production does not occur during winter. Benthic community structure remained stable in both, temperate and polar sediments on the level of cell counts and 16S rRNA-based taxonomy. Actinobacteriota of uncultured Actinomarinales and Microtrichales were a major group, with 8 ± 1% of total reads (Helgoland) and 31 ± 6% (Svalbard). Their high activity (frequency of dividing cells 28%) and in situ cell numbers of 〉10% of total microbes in Svalbard sediments, suggest Actinomarinales and Microtrichales as key heterotrophs for carbon mineralization. Even though Helgoland and Svalbard sampling sites showed no phytodetritus-driven changes of the benthic bacterial community structure, they harbored significantly different communities (p 〈 0.0001, r = 0.963). The temporal stability of benthic bacterial communities is in stark contrast to the dynamic succession typical of coastal waters, suggesting that pelagic and benthic bacterial communities respond to phytoplankton productivity very differently.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2021-12-14
    Description: The Italian earthquake waveform data are collected here in a dataset suited for machine learning analysis (ML) applications. The dataset consists of nearly 1.2 million three-component (3C) waveform traces from about 50 000 earthquakes and more than 130 000 noise 3C waveform traces, for a total of about 43 000 h of data and an average of 21 3C traces provided per event. The earthquake list is based on the Italian Seismic Bulletin (http://terremoti.ingv.it/bsi, last access: 15 February 2020​​​​​​​) of the Istituto Nazionale di Geofisica e Vulcanologia between January 2005 and January 2020, and it includes events in the magnitude range between 0.0 and 6.5. The waveform data have been recorded primarily by the Italian National Seismic Network (network code IV) and include both weak- (HH, EH channels) and strong-motion (HN channels) recordings. All the waveform traces have a length of 120 s, are sampled at 100 Hz, and are provided both in counts and ground motion physical units after deconvolution of the instrument transfer functions. The waveform dataset is accompanied by metadata consisting of more than 100 parameters providing comprehensive information on the earthquake source, the recording stations, the trace features, and other derived quantities. This rich set of metadata allows the users to target the data selection for their own purposes. Much of these metadata can be used as labels in ML analysis or for other studies. The dataset, assembled in HDF5 format, is available at http://doi.org/10.13127/instance (Michelini et al., 2021).
    Description: Published
    Description: 5509–5544
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2022-08-15
    Description: Anaerobic oxidation of ammonium (anammox) in oxygen minimum zones (OMZs) is a major pathway of oceanic nitrogen loss. Ammonium released from sinking particles has been suggested to fuel this process. During cruises to the Peruvian OMZ in April–June 2017 we found that anammox rates are strongly correlated with the volume of small particles (128–512 µm), even though anammox bacteria were not directly associated with particles. This suggests that the relationship between anammox rates and particles is related to the ammonium released from particles by remineralization. To investigate this, ammonium release from particles was modelled and theoretical encounters of free-living anammox bacteria with ammonium in the particle boundary layer were calculated. These results indicated that small sinking particles could be responsible for ~75% of ammonium release in anoxic waters and that free-living anammox bacteria frequently encounter ammonium in the vicinity of smaller particles. This indicates a so far underestimated role of abundant, slow-sinking small particles in controlling oceanic nutrient budgets, and furthermore implies that observations of the volume of small particles could be used to estimate N-loss across large areas.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2024-01-30
    Description: The thermokarst lakes of permafrost regions play a major role in the global carbon cycle. These lakes are sources of methane to the atmosphere although the methane flux is restricted by an ice cover for most of the year. How methane concentrations and fluxes in these waters are affected by the presence of an ice cover is poorly understood. To relate water body morphology, ice formation and methane to each other, we studied the ice of three different water bodies in locations typical of the transition of permafrost from land to ocean in a continuous permafrost coastal region in Siberia. In total, 11 ice cores were analyzed as records of the freezing process and methane composition during the winter season. The three water bodies differed in terms of connectivity to the sea, which affected fall freezing. The first was a bay underlain by submarine permafrost (Tiksi Bay, BY), the second a shallow thermokarst lagoon cut off from the sea in winter (Polar Fox Lagoon, LG) and the third a land-locked freshwater thermokarst lake (Goltsovoye Lake, LK). Ice on all water bodies was mostly methane-supersaturated with respect to atmospheric equilibrium concentration, except for three cores from the isolated lake. In the isolated thermokarst lake, ebullition from actively thawing basin slopes resulted in the localized integration of methane into winter ice. Stable δ13C-CH4 isotope signatures indicated that methane in the lagoon ice was oxidized to concentrations close to or below the calculated atmospheric equilibrium concentration. Increasing salinity during winter freezing led to a micro-environment on the lower ice surface where methane oxidation occurred and the lagoon ice functioned as a methane sink. In contrast, the ice of the coastal marine environment was slightly supersaturated with methane, consistent with the brackish water below. Our interdisciplinary process study shows how water body morphology affects ice formation which mitigates methane fluxes to the atmosphere.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2024-01-30
    Description: Methane emissions from boreal and arctic wetlands, lakes, and rivers are expected to increase in response to warming and associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane emissions to circumpolar scales has contributed to a large uncertainty for our understanding of present-day and future methane emissions. Here we present the Boreal–Arctic Wetland and Lake Dataset (BAWLD), a land cover dataset based on an expert assessment, extrapolated using random forest modelling from available spatial datasets of climate, topography, soils, permafrost conditions, vegetation, wetlands, and surface water extents and dynamics. In BAWLD, we estimate the fractional coverage of five wetland, seven lake, and three river classes within 0.5 × 0.5∘ grid cells that cover the northern boreal and tundra biomes (17 % of the global land surface). Land cover classes were defined using criteria that ensured distinct methane emissions among classes, as indicated by a co-developed comprehensive dataset of methane flux observations. In BAWLD, wetlands occupied 3.2 × 106 km2 (14 % of domain) with a 95 % confidence interval between 2.8 and 3.8 × 106 km2. Bog, fen, and permafrost bog were the most abundant wetland classes, covering ∼ 28 % each of the total wetland area, while the highest-methane-emitting marsh and tundra wetland classes occupied 5 % and 12 %, respectively. Lakes, defined to include all lentic open-water ecosystems regardless of size, covered 1.4 × 106 km2 (6 % of domain). Low-methane-emitting large lakes (〉10 km2) and glacial lakes jointly represented 78 % of the total lake area, while high-emitting peatland and yedoma lakes covered 18 % and 4 %, respectively. Small (〈0.1 km2) glacial, peatland, and yedoma lakes combined covered 17 % of the total lake area but contributed disproportionally to the overall spatial uncertainty in lake area with a 95 % confidence interval between 0.15 and 0.38 × 106 km2. Rivers and streams were estimated to cover 0.12  × 106 km2 (0.5 % of domain), of which 8 % was associated with high-methane-emitting headwaters that drain organic-rich landscapes. Distinct combinations of spatially co-occurring wetland and lake classes were identified across the BAWLD domain, allowing for the mapping of “wetscapes” that have characteristic methane emission magnitudes and sensitivities to climate change at regional scales. With BAWLD, we provide a dataset which avoids double-accounting of wetland, lake, and river extents and which includes confidence intervals for each land cover class. As such, BAWLD will be suitable for many hydrological and biogeochemical modelling and upscaling efforts for the northern boreal and arctic region, in particular those aimed at improving assessments of current and future methane emissions. Data are freely available at https://doi.org/10.18739/A2C824F9X (Olefeldt et al., 2021).
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2024-01-31
    Description: Lakes in permafrost regions are dynamiclandscape components and play an important role for climatechange feedbacks. Lake processes such as mineralizationand flocculation of dissolved organic carbon (DOC), oneof the main carbon fractions in lakes, contribute to thegreenhouse effect and are part of the global carbon cycle.These processes are in the focus of climate research, butstudies so far are limited to specific study regions. Inour synthesis, we analyzed 2167 water samples from 1833lakes across the Arctic in permafrost regions of Alaska,Canada, Greenland, and Siberia to provide first pan-Arcticinsights for linkages between DOC concentrations andthe environment. Using published data and unpublisheddatasets from the author team, we report regional DOCdifferences linked to latitude, permafrost zones, ecoregions,geology, near-surface soil organic carbon contents, andground ice classification of each lake region. The lakeDOC concentrations in our dataset range from 0 to1130 mg L−1(10.8 mg L−1median DOC concentration).Regarding the permafrost regions of our synthesis, wefound median lake DOC concentrations of 12.4 mg L−1(Siberia), 12.3 mg L−1(Alaska), 10.3 mg L−1(Greenland),and 4.5 mg L−1(Canada). Our synthesis shows a significantrelationship between lake DOC concentration and lakeecoregion. We found higher lake DOC concentrationsat boreal permafrost sites compared to tundra sites. Wefound significantly higher DOC concentrations in lakesin regions with ice-rich syngenetic permafrost deposits(yedoma) compared to non-yedoma lakes and a weak butsignificant relationship between soil organic carbon contentand lake DOC concentration as well as between ground icecontent and lake DOC. Our pan-Arctic dataset shows that theDOC concentration of a lake depends on its environmentalproperties, especially on permafrost extent and ecoregion, aswell as vegetation, which is the most important driver of lakeDOC in this study. This new dataset will be fundamental toquantify a pan-Arctic lake DOC pool for estimations of theimpact of lake DOC on the global carbon cycle and climatechange.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2024-04-11
    Description: 〈jats:p〉Abstract. The risk of carbon emissions from permafrost ground is linked to ground temperature and thus in particular to thermal insulation by vegetation and organic soil layers in summer and snow cover in winter. This ground insulation is strongly influenced by the presence of large herbivorous animals browsing for food. In this study, we examine the potential impact of large herbivore presence on the ground carbon storage in thermokarst landscapes of northeastern Siberia. Our aim is to understand how intensive animal grazing may affect permafrost thaw and hence organic matter decomposition, leading to different ground carbon storage, which is significant in the active layer. Therefore, we analysed sites with differing large herbivore grazing intensity in the Pleistocene Park near Chersky and measured maximum thaw depth, total organic carbon content and decomposition state by δ13C isotope analysis. In addition, we determined sediment grain size composition as well as ice and water content. We found the thaw depth to be shallower and carbon storage to be higher in intensively grazed areas compared to extensively and non-grazed sites in the same thermokarst basin. The intensive grazing presumably leads to a more stable thermal ground regime and thus to increased carbon storage in the thermokarst deposits and active layer. However, the high carbon content found within the upper 20 cm on intensively grazed sites could also indicate higher carbon input rather than reduced decomposition, which requires further studies. We connect our findings to more animal trampling in winter, which causes snow disturbance and cooler winter ground temperatures during the average annual 225 days below freezing. This winter cooling overcompensates ground warming due to the lower insulation associated with shorter heavily grazed vegetation during the average annual 140 thaw days. We conclude that intensive grazing influences the carbon storage capacities of permafrost areas and hence might be an actively manageable instrument to reduce net carbon emission from these sites. 〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2024-04-19
    Description: We combine satellite data products to provide a first and general overview of the physical sea ice conditions along the drift of the international Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition and a comparison with previous years (2005–2006 to 2018–2019). We find that the MOSAiC drift was around 20 % faster than the climatological mean drift, as a consequence of large-scale low-pressure anomalies prevailing around the Barents–Kara–Laptev sea region between January and March. In winter (October–April), satellite observations show that the sea ice in the vicinity of the Central Observatory (CO; 50 km radius) was rather thin compared to the previous years along the same trajectory. Unlike ice thickness, satellite-derived sea ice concentration, lead frequency and snow thickness during winter months were close to the long-term mean with little variability. With the onset of spring and decreasing distance to the Fram Strait, variability in ice concentration and lead activity increased. In addition, the frequency and strength of deformation events (divergence, convergence and shear) were higher during summer than during winter. Overall, we find that sea ice conditions observed within 5 km distance of the CO are representative for the wider (50 and 100 km) surroundings. An exception is the ice thickness; here we find that sea ice within 50 km radius of the CO was thinner than sea ice within a 100 km radius by a small but consistent factor (4 %) for successive monthly averages. Moreover, satellite acquisitions indicate that the formation of large melt ponds began earlier on the MOSAiC floe than on neighbouring floes.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    facet.materialart.
    Unknown
    Copernicus
    In:  EPIC3Natural Hazards and Earth System Sciences, Copernicus, 2021, pp. 1-34, ISSN: 1561-8633
    Publication Date: 2024-04-22
    Description: 〈jats:p〉Abstract. The combined effect of hot and dry extremes can have disastrous consequences for the society, economy, and the environment. While a significant number of studies have been conducted regarding the variability of the individual hot or dry extremes in Romania, the evaluation of the combined effect of these extremes (e.g. compound effect) is still lacking for this region. Thus, in this study we have assessed the spatio-temporal variability and trends of hot and dry summers in the eastern part of Europe, focusing on Romania, between 1950 and 2020 and we have analyzed the relationship between the frequency of hot summers and the prevailing large-scale atmospheric circulation. The length, spatial extent and frequency of HWs in Romania has increased significantly over the last 70 years, while for the drought conditions no significant changes have been observed. The rate of increase in the frequency and spatial extent of HWs has accelerated significantly after the 1990’s, while the smallest number of HWs was observed between 1970 and 1985. The hottest years, in terms of heatwave duration and frequency, were 2007, 2012, 2015, and 2019. One of the key drivers of hot summers, over our analyzed region, is the prevailing large-scale circulation, featuring an anticyclonic circulation over the central and eastern parts of Europe and enhanced atmospheric blocking activity associated with positive temperature anomalies underneath. We conclude that our study can help improve our understanding of the spatio-temporal variability of hot and dry summers, especially at the regional scale, as well as their driving mechanisms which might lead to a better predictability of these extreme events. 〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2024-04-22
    Description: Large stocks of soil organic carbon (SOC) have accumulated in the northern hemisphere permafrost region, but their current mounts and future fate remain uncertain. By analyzing an unprecedented dataset combining 〉2,700 soil profiles with environmental variables in a geospatial framework, we generated spatially explicit estimates of permafrost-region SOC stocks, quantified spatial heterogeneity, and identified key environmental predictors. We estimated 1014−175+194 Pg C are stored in the top 3 m of permafrost region soils. The greatest uncertainties occurred in circumpolar toe-slope positions and in flat areas of the Tibetan region. We found that soil wetness index and elevation are the dominant topographic controllers and surface air temperature (circumpolar region) and precipitation (Tibetan region) are significant climatic controllers of SOC stocks. Our results provide the first high-resolution geospatial assessment of permafrost region SOC stocks and their relationships with environmental factors, which are crucial for modeling the response of permafrost affected soils to changing climate.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2024-04-29
    Description: In this study, the first fully continuous monitoring of water vapour isotopic composition at Neumayer Station III, Antarctica, during the 2-year period from February 2017 to January 2019 is presented. Seasonal and synoptic-scale variations in both stable water isotopes H182O and HDO are reported, and their links to variations in key meteorological variables are analysed. In addition, the diurnal cycle of isotope variations during the summer months (December and January 2017/18 and 2018/19) has been examined. Changes in local temperature and specific humidity are the main drivers for the variability in δ18O and δD in vapour at Neumayer Station III, on both seasonal and shorter timescales. In contrast to the measured δ18O and δD variations, no seasonal cycle in the Deuterium excess signal (d) in vapour is detected. However, a rather high uncertainty in measured d values especially in austral winter limits the confidence of this finding. Overall, the d signal shows a stronger inverse correlation with specific humidity than with temperature, and this inverse correlation between d and specific humidity is stronger for the cloudy-sky conditions than for clear-sky conditions during summertime. Back-trajectory simulations performed with the FLEXPART model show that seasonal and synoptic variations in δ18O and δD in vapour coincide with changes in the main sources of water vapour transported to Neumayer Station III. In general, moisture transport pathways from the east lead to higher temperatures and more enriched δ18O values in vapour, while weather situations with southerly winds lead to lower temperatures and more depleted δ18O values. However, on several occasions, δ18O variations linked to wind direction changes were observed, which were not accompanied by a corresponding temperature change. Comparing isotopic compositions of water vapour at Neumayer Station III and snow samples taken in the vicinity of the station reveals almost identical slopes, both for the δ18O–δD relation and for the temperature–δ18O relation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
  • 53
    Publication Date: 2021-01-01
    Electronic ISSN: 0718-1876
    Topics: Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
  • 55
    Publication Date: 2021-01-01
    Electronic ISSN: 0718-1876
    Topics: Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2021-01-01
    Electronic ISSN: 0718-1876
    Topics: Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
  • 58
    Publication Date: 2021-08-20
    Description: The Kadomtsev–Petviashvili equation is known to be the leading term of a semi-infinite hierarchy of integrable equations with evolutions given by times with positive numbers. Here, we introduce new hierarchy directed to negative numbers of times. The derivation of such systems, as well as the corresponding hierarchy, is based on the commutator identities. This approach enables introduction of linear differential equations that admit lifts up to nonlinear integrable ones by means of the special dressing procedure. Thus, one can construct not only nonlinear equations, but corresponding Lax pairs as well. The Lax operator of this evolution coincides with the Lax operator of the “positive” hierarchy. We also derive (1 + 1)-dimensional reductions of equations of this hierarchy.
    Electronic ISSN: 2227-7390
    Topics: Mathematics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2021-08-20
    Description: Among industrially important pyridoxal-5’-phosphate (PLP)-dependent transaminases of fold type IV D-amino acid transaminases are the least studied. However, the development of cascade enzymatic processes, including the synthesis of D-amino acids, renewed interest in their study. Here, we describe the identification, biochemical and structural characterization of a new D-amino acid transaminase from Haliscomenobacter hydrossis (Halhy). The new enzyme is strictly specific towards D-amino acids and their keto analogs; it demonstrates one of the highest rates of transamination between D-glutamate and pyruvate. We obtained the crystal structure of the Halhy in the holo form with the protonated Schiff base formed by the K143 and the PLP. Structural analysis revealed a novel set of the active site residues that differ from the key residues forming the active sites of the previously studied D-amino acids transaminases. The active site of Halhy includes three arginine residues, one of which is unique among studied transaminases. We identified critical residues for the Halhy catalytic activity and suggested functions of the arginine residues based on the comparative structural analysis, mutagenesis, and molecular modeling simulations. We suggested a strong positive charge in the O-pocket and the unshaped P-pocket as a structural code for the D-amino acid specificity among transaminases of PLP fold type IV. Characteristics of Halhy complement our knowledge of the structural basis of substrate specificity of D-amino acid transaminases and the sequence-structure-function relationships in these enzymes.
    Electronic ISSN: 1420-3049
    Topics: Chemistry and Pharmacology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2021-08-19
    Description: Non-persistent viruses classically cause transient, acute infections triggering immune responses aimed at the elimination of the pathogen. Successful viruses evolved strategies to manipulate and evade these anti-viral defenses. Symptoms during the acute phase are often linked to dysregulated immune responses that disappear once the patient recovers. In some patients, however, symptoms persist or new symptoms emerge beyond the acute phase. Conditions resulting from previous transient infection are termed post-acute sequelae (PAS) and were reported for a wide range of non-persistent viruses such as rota-, influenza- or polioviruses. Here we provide an overview of non-persistent viral pathogens reported to be associated with diverse PAS, among them chronic fatigue, auto-immune disorders, or neurological complications and highlight known mechanistic details. Recently, the emergence of post-acute sequelae of COVID-19 (PASC) or long COVID highlighted the impact of PAS. Notably, PAS of non-persistent infections often resemble symptoms of persistent viral infections, defined by chronic inflammation. Inflammation maintained after the acute phase may be a key driver of PAS of non-persistent viruses. Therefore, we explore current insights into aberrant activation of innate immune signaling pathways in the post-acute phase of non-persistent viruses. Finally, conclusions are drawn and future perspectives for treatment and prevention of PAS are discussed.
    Electronic ISSN: 2073-4409
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2021-08-20
    Description: Dispersion of lead (Pb) in mine wastes was simulated for reproducing Pb contamination of soil in Kabwe District, Zambia. Local weather data of year 2019 were monitored in situ and used for the simulations. The plume model, weak puff model, and no puff model were adopted for calculation of Pb dispersion under different wind conditions. The results showed that Pb dispersion from the Kabwe mine was directly affected by wind directions and speeds in the dry season, although it was not appreciably affected in the rainy season. This may be because the source strength is lower in the rainy season due to higher water content of the surface. This indicates that Pb dispersion patterns depend on the season. In addition, the distribution of the amount of deposited Pb-bearing soils around the mine corresponded to the distribution of Pb contents in soils. These results suggest that Pb contamination in soils primarily results from dispersion of fine mine wastes.
    Electronic ISSN: 2075-163X
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2021-08-19
    Description: This paper proposes an equivalent circuit model to obtain the transient electrical stress quantitatively in medium voltage medium frequency transformers in modern power electronics. To verify this model, transient simulation is performed on a 1.5 kV/1 kHz transformer, revealing voltage overshoot quantitatively between turns and layers of the transformer’s HV winding. Effects of rise time of the input pulse voltage, stray capacitance of the winding insulation, and their interactions on the voltage overshot magnitude are presented. With these results, we propose limiting the voltage overshoot and, thereafter, enhancing medium voltage medium frequency transformer’s insulation capability, which throws light on the transformer’s insulation design. Additionally, guidance on the future studies on aging and endurance lifetime of the medium voltage medium frequency transformer’s insulation could be given.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2021-08-20
    Description: Since reinforced concrete (RC) buildings have long service life, cutout openings are generally needed in their load-bearing walls as a sustainable solution in order to meet new requirements of their users. However, the cutout openings decrease the load-bearing capacity of the walls, which may result in the failure of the buildings. In this paper, we investigate the possibility of making a door opening in a load-bearing RC wall of an existing building in Gävle in Sweden. The wall studied in the current paper rests on two individual supports at its two ends; thus, it is considered as a deep beam. However, it is called an examined wall (EW) here. The StruSoft FEM-Design software is used in this study to model, analyze, and design the building based on the Eurocodes and Swedish national annex. The potential need for the EW to be strengthened when the cutout opening is made is also evaluated. It is concluded that strengthening the EW with cutout opening is needed. Different strengthening solutions are proposed for the EW. Moreover, the situation of the EW with the solutions is assessed with regard to the utilization ratio, deflection, and weight. Consequently, it is demonstrated that the proposed strengthening solutions function well for the EW.
    Electronic ISSN: 2075-5309
    Topics: Architecture, Civil Engineering, Surveying
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2021-08-19
    Description: In the current era of a strongly competitive business environment, it is more difficult for companies to attract customers. Consumer neuroscience has growing potential here, as it reveals internal consumer preferences by using innovative methods and tools, which can effectively examine consumer behavior and attract new customers. In particular, smell has a great ability to subconsciously influence customers and, thus, support profitability. This paper examines the importance of consumer neuroscience and its modern technologies used for exploring human perceptions to influence customers and benefit from the aromatization of business spaces. We focused our analysis on various service sectors. Despite the potential of the examined issue, there are a limited number of studies in the field of service providers that use neuroscience tools to examine the effect of aromas on human emotions. Most studies took place in laboratory conditions, and the used methodological procedures varied widely. Our analysis showed that, in spite of the positive impact of aromatization in the majority of aromatized spaces, service companies still do not use the potential of consumer neuroscience and aroma marketing to a sufficient degree. Innovative methods and tools, in particular, are still very underused.
    Electronic ISSN: 2076-3417
    Topics: Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2021-08-20
    Description: The Kuroshio is the strongest warm current in the western North Pacific, which plays a crucial role in climate and human activities. In terms of this, the accurate acquisition of ocean surface current velocity and direction in the Kuroshio region is of great research value. Gaofen-3 synthetic aperture radar (SAR) provides data support for the study of ocean surface current measurements in the Kuroshio region, but no relevant experimental result has been published yet. In this paper, four available stripmap mode SARs’ data acquired by Gaofen-3 in the Kuroshio region are used for measuring the ocean surface current field. In general, the Doppler centroid anomaly (DCA) estimation is a common method to infer ocean surface currents from single-antenna stripmap data, but only the radial velocity component can be retrieved. In order to measure current vectors, a novel method combining the sub-aperture processing and the least squares (LS) technology is suggested and demonstrated by applying to the Gaofen-3 SAR data processing. The experiment’s results agree well with model-derived ocean current data, indicating that the Gaofen-3 SAR has the capability to accurately retrieve the ocean surface current field in the Kuroshio region and motivate further research by providing more data.
    Electronic ISSN: 2076-3417
    Topics: Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2021-08-20
    Description: The C1q/TNF-related protein 3 (CTRP3) represents a pleiotropic adipokine reciprocally associated with obesity and type 2 diabetes mellitus and exhibits anti-inflammatory properties in relation to lipopolysaccharides (LPS)-mediated effects in adipocytes, as well as monocytes/macrophages. Here, we focused on the influence of CTRP3 on LPS-mediated effects in endothelial cells in order to expand the understanding of a possible anti-inflammatory function of CTRP3 in a setting of endotoxemia. An organ- and tissue-specific expression analysis by real-time PCR revealed a considerable Ctrp3 expression in various adipose tissue compartments; however, higher levels were detected in the aorta and in abundantly perfused tissues (bone marrow and the thyroid gland). We observed a robust Ctrp3 expression in primary endothelial cells and a transient upregulation in murine endothelial (MyEND) cells by LPS (50 ng/mL). In MyEND cells, CTRP3 inhibited the LPS-induced expression of interleukin (Il)-6 and the tumor necrosis factor (Tnf)-α, and suppressed the LPS-dependent expression of the major endothelial adhesion molecules Vcam-1 and Icam-1. The LPS-induced adhesion of monocytic cells to an endothelial monolayer was antagonized by CTRP3. In C57BL/6J mice with an LPS-induced systemic inflammation, exogenous CTRP3 did not affect circulating levels of TNF-α, ICAM-1, and VCAM-1. In conclusion, we characterized CTRP3 beyond its function as an adipokine in a setting of vascular inflammation. CTRP3 inhibited LPS-induced endothelial expression of adhesion molecules and monocyte cell adhesion, indicating an important vascular anti-inflammatory role for CTRP3 in endotoxemia.
    Electronic ISSN: 2073-4409
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2021-08-20
    Description: The development of an efficient pretreatment, prior to enzymatic hydrolysis, is a good strategy for the sustainable use of refractory fish byproducts. This study compared hydrothermal pretreatments at 159 °C for 2 min, followed by water extraction (steam explosion-assisted extraction, SE) and 121 °C for 70 min (hot-pressure extraction, HPE), for the recovery of proteins from fish backbones. The effect of enzymatic hydrolysis on the properties of the obtained fish bone protein (FBP) was also evaluated. The results demonstrated that FBP had high contents of protein (81.09–84.88 g/100 g) and hydroxyproline (70–82 residues/1000 residues). After hydrolysis with Flavourzyme, for 3 h, the FBP hydrolysates that were pretreated with SE (SFBP-H) exhibited a better degree of hydrolysis (DH) and nitrogen recovery (NR), and a higher level of umami taste free amino acids (151.50 mg/100 mL), compared with the HPE-treated samples. The obtained SFBP-H mainly distributed below 3000 Da and had strong scavenging effects on 1,1-diphenyl-2-picrylhydrazy (DPPH) (IC50 = 4.24 mg/mL) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) (IC50 = 1.93 mg/mL) radicals. Steam explosion-assisted extraction is a promising route for recovering proteins from native fish bone materials, and improving the flavor and antioxidant activity of the hydrolysates.
    Electronic ISSN: 2304-8158
    Topics: Chemistry and Pharmacology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2021-08-19
    Description: Since mineral supplements for horses commonly contain macro minerals, although the requirement for such is usually covered by roughage-based diets, the aim of this study was to investigate the effects of different dietary calcium levels on mineral serum concentrations and bone metabolism. The trial was conducted in 30 young warmblood stallions (2–3 years) that were divided into two groups for a five-month feeding trial. The groups were fed a hay- and oat-based diet and were either supplied with high (Ca-High) or moderate (Ca-Moderate) calcium excess. While in Ca-High calcium supply was about 2–2.5-fold of the requirement, in Ca-Moderate calcium requirements were slightly surpassed (1.5–1.6-fold). In order to monitor the effects of the different calcium supply, blood samples were taken during the trial and analysed for levels of macro and trace elements as well as concentrations of two bone markers. In Ca-Moderate a trend towards higher phosphorus serum levels compared to Ca-High was observed which was significant at the end of the trial (p = 0.0002). Furthermore, results showed no influence of the diet on bone markers. Results support the idea that forage-based rations for horses do not necessarily have to be supplemented with macro minerals but with trace elements.
    Electronic ISSN: 2076-2615
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2021-08-20
    Description: COVID-19 might have long-term mental health impacts. We aim to investigate the longitudinal changes in mental problems from initial COVID-19 peak to its aftermath among general public in China. Depression, anxiety and insomnia were assessed among a large-sample nationwide cohort of 10,492 adults during the initial COVID-19 peak (28 February 2020 to 11 March 2020) and its aftermath (8 July 2020 to 8 August 2020) using the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Insomnia Severity Index. We used generalized estimating equations and linear mixed models to explore factors associated with long-term mental health symptoms during COVID-19. During the five months, mental health symptoms remained consistently elevated (baseline 46.4%; follow-up 45.1%). Long-term depression, anxiety and insomnia were associated with several personal and work-related factors including quarantine (adjusted OR for any mental health symptoms 1.31, 95%CI 1.22–1.41, p 〈 0.001), increases in work burden after resuming work (1.77, 1.65–1.90, p 〈 0.001), occupational exposure risk to COVID-19 (1.26, 1.14–1.40, p 〈 0.001) and living in places severely affected by initial COVID-19 peak (1.21, 1.04–1.41, p = 0.01) or by a COVID-19 resurgence (1.38, 1.26–1.50, p 〈 0.001). Compliance with self-protection measures, such as wearing face masks (0.74, 0.61–0.90, p = 0.003), was associated with lower long-term risk of mental problems. The findings reveal a pronounced and prolonged mental health burden from the initial COVID-19 peak through to its aftermath in China. We should regularly monitor the mental health status of vulnerable populations throughout COVID-19.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2021-08-19
    Description: Low-cost air quality stations can provide useful data that can offer a complete picture of urban air quality dynamics, especially when integrated with daily measurements from reference air quality stations. However, the success of such deployment depends on the measurement accuracy and the capability of resolving spatial and temporal gradients within a spatial domain. In this work, an ensemble of three low-cost stations named “AirQino” was deployed to monitor particulate matter (PM) concentrations over three different sites in an area affected by poor air quality conditions. Data of PM2.5 and PM10 concentrations were collected for about two years following a protocol based on field calibration and validation with a reference station. Results indicated that: (i) AirQino station measurements were accurate and stable during co-location periods over time (R2 = 0.5–0.83 and RMSE = 6.4–11.2 μg m−3; valid data: 87.7–95.7%), resolving current spatial and temporal gradients; (ii) spatial variability of anthropogenic emissions was mainly due to extensive use of wood for household heating; (iii) the high temporal resolution made it possible to detect time occurrence and strength of PM10 concentration peaks; (iv) the number of episodes above the 1-h threshold of 90 μg m−3 and their persistence were higher under urban and industrial sites compared to the rural area.
    Electronic ISSN: 2073-4433
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2021-08-20
    Description: Retinal dystrophies (RD) are clinically and genetically heterogenous disorders showing mutations in over 270 disease-associated genes. Several millions of people worldwide are affected with different types of RD. Studying the relevance of disease-associated sequence alterations will assist in understanding disorders and may lead to the development of therapeutic approaches. Here, we established a whole exome sequencing (WES) pipeline to rapidly identify disease-associated mutations in patients. Sanger sequencing was applied to identify deep-intronic variants and to verify the co-segregation of WES results within families. We analyzed 26 unrelated patients with different syndromic and non-syndromic clinical manifestations of RD. All patients underwent ophthalmic examinations. We identified nine novel disease-associated sequence variants among 37 variants identified in total. The sequence variants located to 17 different genes. Interestingly, two cases presenting with Stargardt disease carried deep-intronic variants in ABCA4. We have classified 21 variants as pathogenic variants, 4 as benign/likely benign variants, and 12 as variants of uncertain significance. This study highlights the importance of WES-based mutation analyses in RD patients supporting clinical decisions, broadly based genetic diagnosis and support genetic counselling. It is essential for any genetic therapy to expand the mutation spectrum, understand the genes’ function, and correlate phenotypes with genotypes.
    Electronic ISSN: 2073-4425
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2021-08-20
    Description: Developments in the design of wind turbines with augmentation are advancing around the globe with the goal of generating electricity close to the user in built-up areas. This is certain to help lessen the power generation load as well as distribution and transmission network costs by reducing the distance between the user and the power source. The main objectives driving the development and advancement of vertical-axis wind turbines are increasing the power coefficient and the torque coefficient by optimizing the upstream wind striking on the rotor blades. Unlike horizontal-axis wind turbines, vertical axis turbines generate not only positive torque but also negative torque during operation. The negative torque generated by the returning blade is a key issue for vertical-axis wind turbines (VAWTs) that is counterproductive. Installation of wind deflectors for flow augmentation helps to reduce the negative torque generated by the returning blades as well as enhance the positive torque by creating a diversion in the upstream wind towards the forwarding blade during operation. This paper reviews various designs, experiments, and CFD simulations of wind deflectors reported to date. Optimization techniques for VAWTs incorporating wind deflectors are discussed in detail. The main focus of the review was on the installation position and orientation of the deflectors and their potential contribution to increasing the power coefficient. Topics for future study are suggested in the conclusion section of the paper.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2021-08-20
    Description: Exploring differences in clinical outcomes based on race and origin among patients hospitalized for COVID-19 is a controversial issue. The ALC COVID-19 Registry includes all confirmed COVID-19 patients admitted to hospital from 3 March 2020 to 17 December 2020. The data were obtained from electronic health records in order to evaluate the differences in the clinical features and outcomes among European and Latin American patients. The follow-ups occurred after 156 days. A propensity score weighting (PSW) logistic regression model was used to estimate the odds ratio (OR, 95% CI) for Latin American origin and outcome associations. Of the 696 patients included, 46.7% were women, with a median age of 65 (IQR 53–67) years, 614 (88.2%) were European, and 82 (11.8%) were Latin American. Latin American patients were younger, with fewer comorbidities, and a higher incidence of extensive pneumonia. After adjusting for residual confounders, Latin American origin was not associated with an increased risk of death (PSW OR 0.85 (0.23–3.14)) or with the need for invasive mechanical ventilation (PSW OR 0.35 (0.12–1.03)). Latin American origin was associated with a shorter hospital stay, but without differences in how long the patient remained on mechanical ventilation. In a public healthcare system, the rates of death or mechanical ventilation in severe COVID-19 cases were found to be comparable between patients of European and Latin American origins.
    Electronic ISSN: 2076-2607
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2021-08-19
    Description: The huge energy potential of Enhanced Geothermal Systems (EGS) makes them perspective sources of non-intermittent renewable energy for the future. This paper focuses on potential scenarios of EGS development in a locally and in regard to geothermal exploration, poorly known geological setting—the Variscan fold-and-thrust belt —for district heating and cooling of the Göttingen University campus. On average, the considered single EGS doublet might cover about 20% of the heat demand and 6% of the cooling demand of the campus. The levelized cost of heat (LCOH), net present value (NPV) and CO2 abatement cost were evaluated with the help of a spreadsheet-based model. As a result, the majority of scenarios of the reference case are currently not profitable. Based on the analysis, EGS heat output should be at least 11 MWth (with the brine flow rate being 40 l/s and wellhead temperature being 140 °C) for a potentially profitable project. These parameters can be a target for subsurface investigation, reservoir modeling and hydraulic stimulation at a later stage. However, sensitivity analysis presented some conditions that yield better results. Among the most influential parameters on the outcome are subsidies for research wells, proximity to the campus, temperature drawdown and drilling costs. If realized, the EGS project in Göttingen might save up to 18,100 t CO2 (34%) annually.
    Electronic ISSN: 2076-3263
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2021-08-20
    Description: Transport infrastructure (TI) plays a crucial role in socioeconomic development. The increase of TI inequality, an all-pervading phenomenon in both developed and developing countries, has been an obstacle to sustainable economic growth. The relationship between TI inequality and economic growth has attracted considerable interest over the past three decades. However, the relationship remains obscure, and people find it impossible to utilize to develop economies. This study collected a panel of empirical data from 1982 to 2015 from China to calculate the Gini coefficient and conduct the Granger causality test. The data analysis results show that TI inequality is not always conducive to economic growth. A softening TI inequality helps address the issues of uneven economic growth across regions in the long term. The short-term effects of improving TI inequality at the national level are reflected in the network effect. In addition, the “social filters” facilitate the region to absorb the economic benefits brought by the improvement of TI inequality. These findings offer a way to address the increase of TI inequality and shed light on the ways to improve transport investment from the perspective of economic growth.
    Electronic ISSN: 2073-445X
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2021-08-20
    Description: Black soldier fly (Hermetia illucens) larvae (BSFL) are a promising, sustainable source of nutrients, however, there is limited knowledge regarding the food safety of consuming BSFL. This study determined the safety of consuming BSFL for direct human consumption in terms of microbial, heavy metal and allergen content. Microbial counts were determined using ISO (International Organization for Standardization) methods, heavy metals were determined using inductively coupled plasma mass spectrometry and allergens were determined via Orbitrap mass spectrometry and ELISA (enzyme-linked immunosorbent assay) kits. Feed and killing method influenced the presence of Bacillus cereus (p = 0.011), and only the killing method influenced Escherichia coli (p 〈 0.00) and total viable count (TVC) (p 〈 0.00). Blanching resulted in a 3-log reduction in E. coli and a 3.4 log reduction in the TVC counts. Salmonella spp. and Listeria spp. were not detected in the BSFL samples. Heavy metals were detected although they were below maximum legal limits. Cross-reactive allergens, tropomyosin and arginine kinase, were detected in the BSFL samples, although the clinical significance requires research. The feed fed to the BSFL and blanching were found to influence the safety of consuming BSFL, highlighting the importance of incorporating sufficient decontamination steps, such as blanching, to ensure food safety.
    Electronic ISSN: 2304-8158
    Topics: Chemistry and Pharmacology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2021-08-20
    Description: Malaysia implemented its first Movement Control Order (MCO) during the early phase of the COVID-19 pandemic to slow the transmission of the virus. This study aimed to explore the public perception of the MCO implementation and people’s experiences during this period. The study employed qualitative explorative in-depth interviews conducted with 23 Malaysian adults from various demographic backgrounds. Thematic analysis was performed using NVivo 12. Three main themes were identified: a period of information surge, heterogeneous emotional response, and attempts to adapt. During the MCO, the participants obtained information from multiple platforms. They suggested the need for clear and repeated instructions to avoid confusion and misinformation. They also acknowledged the importance of the MCO in breaking the chain of transmission and safeguarding high-risk groups; however, they also expressed that stricter enforcement from the authorities was warranted. The changes in the participants’ work–life routines, lack of physical interaction, and uncertainty about their health and the economy due to the MCO negatively impacted their psychological states. Despite these challenges, the participants attempted to adapt to life under the MCO in different ways. The findings imply that during a crisis, the public tends to seek clear and reliable information, experience emotional turmoil, and adapt to changes. The MCO implementation can be improved through an effective communication strategy and efforts to battle misinformation.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2021-08-19
    Description: This case series study aimed to evaluate the safety, feasibility, and positive outcome of the neurorehabilitation multimodal protocol (NRMP) in 16 chronic post-surgical IVDD Hansen type I dogs, with OFS 0/DPP− (n = 9) and OFS 1/DPP+ (n = 7). All were enrolled in the NRMP for a maximum of 90 days and were clinically discharged after achieving ambulation. The NRMP was based on locomotor training, functional electrical stimulation, transcutaneous electrical spinal cord stimulation, and 4-aminopyridine (4-AP) pharmacological management. In the Deep Pain Perception (DPP)+ dogs, 100% recovered ambulation within a mean period of 47 days, reaching OFS ≥11, which suggests that a longer period of time is needed for recovery. At follow-up, all dogs presented a positive evolution with voluntary micturition. Of the DPP− dogs admitted, all achieved a flexion/extension locomotor pattern within 30 days, and after starting the 4-AP, two dogs were discharged at outcome day 45, with 78% obtaining Spinal Reflex Locomotion (SRL) and automatic micturition within a mean period of 62 days. At follow-up, all dogs maintained their neurological status. After the NRMP, ambulatory status was achieved in 88% (14/16) of dogs, without concurrent events. Thus, an NRMP may be an important therapeutic option to reduce the need for euthanasia in the clinical setting.
    Electronic ISSN: 2076-2615
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2021-08-19
    Description: Increasing the bearing capacity of reinforced concrete structures, reducing material consumption, and ensuring quality are critical in modern construction. The article presents an experimental study of the ultimate compressive strains of short fiber basalt reinforced concrete columns and provides recommendations for increasing the bearing capacity using steel reinforcement bars with greater strength. The columns were tested in an upright position using a hydraulic press. Strains were measured with dial indicators and a strain gauge station. It was shown that the addition of 10% coarse basalt fiber increased the ultimate compressibility of concrete on ordinary crushed stone by 19.8%, and expanded clay concrete by 26.1%, which led to the strain hardening of concrete under compression by 9.0% and 12%, respectively. Ultimate compressive strains in fiber-reinforced concrete short columns with combined reinforcement increased 1.42 times in columns on a lightweight aggregate and 1.19 times on heavy aggregate. An increase in the ultimate compressibility of concrete makes it possible to use steel reinforcement with greater strength in compressed elements as the concrete crushing during compression occurs primarily due to the reaching of critical values by tensile stresses in the transverse direction. This makes it possible to manufacture structures with a higher load-bearing capacity and less material consumption. A practical example of the application of the proposed approach is given.
    Electronic ISSN: 2076-3417
    Topics: Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2021-08-19
    Description: The threshing of frozen corn is accompanied by breakage and adherence, which influence the cleaning performance when the corn-cleaning mixture is separated and cleaned. In order to reduce the impurity ratio and loss ratio during frozen corn cleaning and provide theoretical support for frozen corn combine harvesting, this study employed a self-made air-screen cleaning system with adjustable parameters. The optimal process parameters of frozen corn cleaning were determined by using the response surface method (RSM). The influences of the fan speed (FS), vibrational frequency (VF), and screen opening (SO) on the cleaning performance were explored. The results showed that all three process parameters had significant effects on the impurity ratio (IR) and loss ratio (LR). The fan speed had the most significant impact. The cleaning performance was optimal when the fan speed was 102.7 rad/s, the vibration frequency was 6.42 Hz, and the screen opening was 21.9 mm, corresponding to a 0.80% impurity ratio and a 0.61% loss ratio. The predicted values of the regression models were consistent with the experimental results with a relative error of less than 5%. The reliability and accuracy of regression models were established and confirmed.
    Electronic ISSN: 2077-0472
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2021-08-19
    Description: Prophylactic antibiotic usage during delivery is a common practice worldwide, especially in low- to middle-income countries. Guidelines have been published to reduce antibiotic overuse; however, data describing the use of prophylactic antibiotics and clinician adherence to guidelines in low- to middle-income countries remain limited. This study aimed to describe the prevalence of prophylactic antibiotic use, factors associated with its use, and clinician adherence to guidelines. A retrospective review was conducted for all deliveries from 1 January 2016 to 31 December 2018 at a tertiary level hospital in Indonesia. The prevalence of prophylactic antibiotic use during delivery was 47.1%. Maternal education level, Ob/Gyn specialist-led delivery, a history of multiple abortions, C-section, premature membrane rupture, and antepartum hemorrhage were independently associated with prophylactic antibiotic use. Clinician adherence to the guidelines was 68.9%. Adherence to guidelines was the lowest in conditions where the patient had only one indication for prophylactic antibiotics (aOR 0.36, 95% CI 0.24–0.54). The findings showed that the prevalence of prophylactic antibiotic use during delivery was moderate to high. Adherence to local guidelines was moderate. Updating the local prescribing guidelines may improve clinician adherence.
    Electronic ISSN: 2079-6382
    Topics: Chemistry and Pharmacology , Medicine
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2021-08-19
    Description: Phenolic compounds have long been of great importance in the pharmaceutical, food, and cosmetic industries. Unfortunately, conventional extraction procedures have a high cost and are time consuming, and the solvents used can represent a safety risk for operators, consumers, and the environment. Deep eutectic solvents (DESs) are green alternatives for extraction processes, given their low or non-toxicity, biodegradability, and reusability. This review discusses the latest research (in the last two years) employing DESs for phenolic extraction, solvent components, extraction yields, extraction method characteristics, and reviewing the phenolic sources (natural products, by-products, wastes, etc.). This work also analyzes and discusses the most relevant DES-based studies for phenolic extraction from natural sources, their extraction strategies using DESs, their molecular mechanisms, and potential applications.
    Electronic ISSN: 1420-3049
    Topics: Chemistry and Pharmacology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2021-08-19
    Description: Fungi from the Candida genus are widespread commensals and, at the same time, are the leading cause of fungal infections worldwide. For instance, vulvovaginal candidiasis (VVC) affects approximately 75% of women at least once in their lifetime, remaining the second most common gynecological infection. On the contrary, hospital-acquired fungal bloodstream infections (BSIs), although less frequent, are characterized by a high mortality rate. Undoubtedly, the main reason for this situation are virulence factors that these yeast-like fungi can produce, and the ability to form a biofilm is one of the most important of them.. Due to the low effectiveness of classic antimycotics against Candida biofilms, an intense search for new drugs capable of eradicating this structure is highly demanded. One of the most promising groups of compounds exhibiting such properties are antimicrobial peptides (AMPs). This study focuses on a comparison of the efficacy of Omiganan and fluconazole alone and in combination against Candida strains isolated from BSIs. The obtained results are consistent with our previous reports on the effectiveness of Omiganan against clinical strains isolated from VVC. This is also the first report on the combinatory application of Omiganan in the context of fungal BSI. The majority of combinations with fluconazole showed an additive effect, as well as a synergistic effect in the range of certain concentrations. Importantly, such effects are visible at concentrations much lower than for those compounds used individually. Potentially, this entails the possibility of limiting the adverse effects (e.g., toxicity) of Omiganan and fluconazole applied in vivo, thus improving the safety profile of this particular antifungal therapy.
    Electronic ISSN: 2079-6382
    Topics: Chemistry and Pharmacology , Medicine
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2021-08-19
    Description: This empirical study assesses the effect of CO2 emissions, urbanization, energy consumption, and agriculture on Thailand’s economic growth using a dataset between 1970 and 2018. The ARDL and the frequency domain causality (FDC) approaches were applied to assess these interconnections. The outcome of the bounds test suggested a long-term association among the variables of investigation. The ARDL outcomes reveal that urbanization, agriculture, energy consumption, and CO2 emissions positively trigger Thailand’s economic growth. Additionally, the frequency domain causality test was used to detect a causal connection between the series. The main benefit of this technique is that it can detect a causal connection between series at different frequencies. To the understanding of the authors, this is the first study in the case of Thailand that will apply the FDC approach to capture the causal linkage between GDP and the regressors. The outcomes of the causality test suggested that CO2 emissions, urbanization, energy consumption, and agriculture can predict Thailand’s economic growth in the long term. These outcomes have far-reaching implications for economic performance and Thailand’s macroeconomic indicators.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2021-08-20
    Description: The muskrat is a neozoon species that has occupied many countries of continental North Europe after its introduction from north America as fur animals. Due to its burrowing activity it damages river and canal banks and structures of flood control. For this reason, the eradication of this alien species is recommended. Muskrats are also of parasitological interest since they can act as suitable intermediate hosts for Echinococcus multilocularis. On the other hand, little is known on the other helminths that infect muskrats. A total of 130 muskrats of different age groups trapped in different habitats in the Barnim district of the Brandenburg state by a professional hunter were examined for parasites and seven trematodes (Echinostoma sp., Notocotylus noyeri, Plagiorchis elegans, Plagiorchis arvicolae, Psilosostoma simillimum, P. spiculigerum, Opisthorchis felineus and four larval cestode species (Hydatigera taeniaeformis, Taenia martis, Taenia polyacantha, Taenia crassiceps) were detected. Larval stages of E. multilocularis were not found. O. felineus was found for the first time in muskrats in Germany. All the named parasites were present in Europe prior to the introduction of muskrats. With a prevalence of 48.9%, Strobilocercus fasciolaris, the larval stage of the cat tapeworm, H. taeniaeformis, was the most frequent parasite found in adult muskrats.
    Electronic ISSN: 2076-2615
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2021-08-20
    Description: C-type natriuretic peptide (CNP) is an important vascular regulator that is present in the brain. Our previous study demonstrated the innate neuroprotectant role of CNP in the neonatal brain after hypoxic-ischemic (HI) insults. In this study, we further explored the role of CNP in cerebrovascular pathology using both in vivo and in vitro models. In a neonatal mouse HI brain injury model, we found that intracerebroventricular administration of recombinant CNP dose-dependently reduces brain infarct size. CNP significantly decreases brain edema and immunoglobulin G (IgG) extravasation into the brain tissue, suggesting a vasculoprotective effect of CNP. Moreover, in primary brain microvascular endothelial cells (BMECs), CNP dose-dependently protects BMEC survival and monolayer integrity against oxygen-glucose deprivation (OGD). The vasculoprotective effect of CNP is mediated by its innate receptors NPR2 and NPR3, in that inhibition of either NPR2 or NPR3 counteracts the protective effect of CNP on IgG leakage after HI insult and BMEC survival under OGD. Of importance, CNP significantly ameliorates brain atrophy and improves neurological deficits after HI insults. Altogether, the present study indicates that recombinant CNP exerts vascular protection in neonatal HI brain injury via its innate receptors, suggesting a potential therapeutic target for the treatment of neonatal HI brain injury.
    Print ISSN: 1661-6596
    Electronic ISSN: 1422-0067
    Topics: Chemistry and Pharmacology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2021-08-20
    Description: The number of medically compromised dental patients is increasing every year with the increase in the super-aged population. Many of these patients have underlying psychiatric problems and diseases, which need to be recognized by dental professionals for better treatment outcomes. The aim of this narrative review article is to summarize the psychological and psychiatric backgrounds of medically compromised patients who are frequently visited and taken care of by dentists using findings from recent systematic reviews and meta-analyses. Anxiety and symptoms of depression, post-traumatic stress disorders, panic disorders, poor cognitive functions, and poor quality of life were some of the common psychological backgrounds in medically compromised patients. Additionally, the consequences of these psychological problems and the considerations that need to be taken by the dentist while treating these patients have been discussed. Dental professionals should be aware of and recognize the different psychological backgrounds of medically compromised dental patients in order to provide appropriate dental treatment and to prevent oral conditions from worsening.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2021-08-20
    Description: Water uptake is a seminal process in seed germination. Salt and polyethylene glycol (PEG) are known to retard seed germination rates and percentages, which is often attributed to osmotic effects. Here, we quantified water uptake in wheat seeds killed with a hot needle, finding evidence of three distinct water uptake pools. The fast pool was unaffected by salt, and likely represents cell walls and other apoplastic material. Water uptake into the medium and slow pools was slowed by salt addition, with the medium pool thought to be cellular, while the slow pool is presumably related to endosperm hydration. Salt caused a minor decrease in the water uptake rates and maximum seed water content, while PEG strongly suppressed both parameters. Seeds transferred between water and salt solutions followed the water uptake trajectories of the solution into which they were transferred. Seeds transferred from PEG to water achieved final seed water contents similar to water control seeds, while seeds transferred from water to PEG achieved significantly higher final water contents than PEG controls. This work confirms that salt and PEG have distinct effects on water uptake by wheat seeds.
    Electronic ISSN: 2073-4395
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Publication Date: 2021-08-20
    Description: Power Factor Correction (PFC) single-phase AC/DC converters are used in several power electronics applications as full wave control rectifiers improving power quality and providing high standards of efficiency. Many papers dealing with the description or use of such topologies have been published in recent years; however, a review that describes and organizes their specific details has not been reported in the technical literature. Therefore, this paper presents an extensive review of PFC single-phase AC/DC converters operating with the Boost converter topology for low and medium voltage as well as and power appliances. A categorization of bridge, semi-bridgeless, and bridgeless, in accordance with the construction characteristics, was carried out in order to unify the technical terminology. Benefits and disadvantages are described and analyzed in detail. Furthermore, a comparison performance in terms of PFC, Total Harmonic Distortion (THD), power capacity, electromagnetic compatibility (EMC), number of elements, and efficiency is included.
    Electronic ISSN: 2076-3417
    Topics: Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Publication Date: 2021-08-20
    Description: Evaluation and monitoring of wireless sensor networks (WSN) and the parameters defining their operations and design, such as energy consumption, latency, and stability, is a complex task due to interaction with real devices. For greater control of these variables, the use of simulators arises as an alternative. Cooja is a WSN simulator/emulator which handles the devices’ controllers and multiple communication protocol implementations, such as RPL (RPL is one of the most used protocol in IoT). However, Cooja does not consider either the implementation of an energy model (it has infinite energy consumption) nor the visual behavior of the topology construction, although these aspects are crucial for effective network analysis and decision taking. This paper presents the design and the implementation of ViTool-BC, a software built on top of Cooja, which allows the creation of different energy estimation models and also to visualize in real time the behavior of WSN topology construction. In addition, ViTool-BC offers a heat map of energy consumption traces. Therefore, this tool helps researchers to monitor in real time the topology construction, node disconnection, and battery depletion, aspects to be considered in the analysis of the available routing protocols in Cooja.
    Electronic ISSN: 2076-3417
    Topics: Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2021-08-20
    Description: Small nucleolar RNA (snoRNA) were one of our earliest recognised classes of non-coding RNA, but were largely ignored by cancer investigators due to an assumption that their activities were confined to the nucleolus. However, as full genome sequences have become available, many new snoRNA genes have been identified, and multiple studies have shown their functions to be diverse. The consensus now is that many snoRNA are dysregulated in cancers, are differentially expressed between cancer types, stages and metastases, and they can actively modify disease progression. In addition, the regulation of the snoRNA class is dominated by the cancer-supporting mTOR signalling pathway, and they may have particular significance to immune cell function and anti-tumour immune responses. Given the recent advent of therapeutics that can target RNA molecules, snoRNA have robust potential as drug targets, either solely or in the context of immunotherapies.
    Electronic ISSN: 2079-7737
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2021-08-20
    Description: The south of Portugal is one of the regions that will be most affected by the impacts of climate change (CC), with an expected increase in water scarcity. Irrigated super-intensive olive orchards occupy a large area of the used agricultural surface in the Alentejo region, south of Portugal, making it necessary to adapt this crop to the effects of CC. This study assessed the impacts of CC and defined adaptation measures concerning irrigation management of the super-intensive olive orchard. To compute the crop irrigation requirement (CIR), the soil water balance model ISAREG was combined with climate data relative to the reference period 1971–2000 and to the representative concentration pathways RCP4.5 and RCP8.5 for the periods 2011–2040, 2041–2070, and 2071–2100. The growing degree-days (GDD) approach was used to estimate olive phenology for these CC scenarios. Unchanged irrigation management with an average CIR increase up to 16% in RCP4.5 and 31% in RCP8.5 is expected. By adopting higher levels of water deficit, water savings of up to 22% can be realized. The results showed that the anticipated CIR increase for the CC scenarios can be mitigated through regulated deficit irrigation strategies.
    Electronic ISSN: 2073-4395
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2021-08-20
    Description: 5-aminolevulinic acid (ALA), a key precursor in the biosynthesis of porphyrins, can improve plant tolerance to various environmental stresses. However, it is unclear whether ALA can improve tolerance in poplar. Here, we investigated the effects of ALA on poplars under drought and salt stresses. ALA pretreatment exhibited less morphological damage, reduced leaf malonaldehyde content (MDA) and electrolyte leakage (EL), and increased leaf relative water content (RWC), proline (PRO), superoxide dismutase (SOD), and peroxidase (POD) content under stresses. Furthermore, exogenous ALA mitigated the decrease in photosynthetic capacity, and restored the chlorophyll content (Chl), net CO2 assimilation rate, stomatal conductance (Gs), transpiration rate (Tr), maximal photochemical quantum yield of PSII (Fv/Fm), actual quantum yield of photosynthesis (YII), and electron transfer rate (ETR) of poplar under various stresses. qRT-PCR showed that ALA up-regulated the expression of antiporters and aquaporins genes, which are associated with Na+ exclusion in the leaf cells and the transport activity of aquaporins. In summary, ALA pretreatment significantly improved the stress tolerance of poplar, decreasing the degree of membrane lipid peroxidation and promoting the photosynthesis and antioxidant capacity of leaves. In addition, our results showed that ALA might mediate Na+ transporter and aquaporins activity, thereby increasing the salt tolerance of poplar.
    Electronic ISSN: 1999-4907
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2021-08-20
    Description: This paper presents the design of NaviPBx, an ultrasound-navigated prostate cancer biopsy system. NaviPBx is designed to support an affordable and sustainable national healthcare program in Senegal. It uses spatiotemporal navigation and multiparametric transrectal ultrasound to guide biopsies. NaviPBx integrates concepts and methods that have been independently validated previously in clinical feasibility studies and deploys them together in a practical prostate cancer biopsy system. NaviPBx is based entirely on free open-source software and will be shared as a free open-source program with no restriction on its use. NaviPBx is set to be deployed and sustained nationwide through the Senegalese Military Health Service. This paper reports on the results of the design process of NaviPBx. Our approach concentrates on “frugal technology”, intended to be affordable for low–middle income (LMIC) countries. Our project promises the wide-scale application of prostate biopsy and will foster time-efficient development and programmatic implementation of ultrasound-guided diagnostic and therapeutic interventions in Senegal and beyond.
    Electronic ISSN: 2313-433X
    Topics: Computer Science
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2021-08-19
    Description: High interstitial level of ATP and its lysate adenosine in the cancer microenvironment are considered a halo mark of cancer. Adenosine acts as a strong immune suppressor. However, the source of ATP release is unclear. We clarified the release of ATP via volume-regulated anion channels (VRACs) in breast cell lines using an ATP luminescence imaging system. We detected a slowly rising diffuse pattern of ATP release that was only observed in undifferentiated cells, not in differentiated primary cultured cells. This was confirmed by suppression with DCPIB, a blocker of VRACs, and shRNA for LRRC8A, an indispensable subunit of VRACs. We herein demonstrated that the inflammatory mediator sphingosine-1-phosphate (S1P), which exists abundantly in the cancer microenvironment, induced a diffuse pattern of ATP release isovolumetrically. The response was dose-dependent and suppressed by the knock-down of LRRC8A. It was also suppressed by blockers of S1P receptor 1 and 2 (W146 and JTE013, respectively). RTqPCR demonstrated the prominent presence of S1PR1 and S1PR2 mRNAs. We discussed the roles of S1P-induced ATP release in the cancer microenvironment.
    Electronic ISSN: 2075-1729
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2021-08-20
    Description: Seaweeds are an important ingredient of functional foods recommended for daily food, due to their unique compositions and nutritional value. Padina tetrastromatica is a brown edible seaweed that is commonly found along the coastal regions of Peninsular Malaysia and consumed as food by some coastal communities. This study investigates the nutritional and antihyperglycaemic potential of P. tetrastromatica extracts, which is generally accepted as an important functional food. In our methodology, we induced diabetes intraperitoneally in experimental animals with a dose of 65 mg kg−1 body weight of streptozotocin. Oral treatment with 200 and 400 mg kg−1 of P. tetrastromatica ethanolic and ethyl acetate extracts were initiated, respectively, to experimental rats once daily for 18 days. Metformin was used as the positive control. Biochemical estimations and histopathological analysis were included in this study. Treatment with P. tetrastromatica extracts significantly lowered the plasma glucose levels in Streptozotocin-induced diabetic rats. In addition, P. tetrastromatica extract treatment also showed a significant reduction in serum alanine transaminase levels. However, no significant changes were observed in serum aspartate transaminase levels. The ethyl acetate extract of P. tetrastromatica at 400 mg kg−1 dose shows some nephroprotective effect, which is observed from the significant increase in the plasma albumin levels. Histopathological evaluation revealed no marked morphological changes in tissues of the isolated organs of the ethyl acetate extract-treated group, revealing the safe nature of P. tetrastromatica.
    Electronic ISSN: 2304-8158
    Topics: Chemistry and Pharmacology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2021-08-20
    Description: The number of fatalities in the construction industry is highest among all industries; thus, various losses in the form of fatalities in construction represent a significant factor for safety management. If a fatality occurs, it is important to estimate the overall loss, as a significant financial loss occurs for each project participant. However, in studies of the cost of accidents involving a fatality conducted abroad, the framework cannot be applied as it is because insurance types, systems, and legal cost systems differ by country. Therefore, we developed a framework for calculating the fatality loss considering various aspects of labor, industry, and regulations in Korea. This was done in four steps: (i) data collection and criteria selection; (ii) proposed framework development; (iii) conduct of questionnaire surveys for the case study; and (iv) analysis and evaluation of the case study. As a result of the data analysis after the case study of general construction companies, the total fatality loss was estimated to be 2,198,260 USD/person. The contributions of this study are the development of a framework composed of newly discovered items that can acquire reliable data in consideration of the properties of the construction industry.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Publication Date: 2021-08-20
    Description: Traditional research methods in software defect prediction use part of the data in the same project to train the defect prediction model and predict the defect label of the remaining part of the data. However, in the practical realm of software development, the software project that needs to be predicted is generally a brand new software project, and there is not enough labeled data to build a defect prediction model; therefore, traditional methods are no longer applicable. Cross-project defect prediction uses the labeled data of the same type of project similar to the target project to build the defect prediction model, so as to solve the problem of data loss in traditional methods. However, the difference in data distribution between the same type of project and the target project reduces the performance of defect prediction. To solve this problem, this paper proposes a cross-project defect prediction method based on manifold feature transformation. This method transforms the original feature space of the project into a manifold space, then reduces the difference in data distribution of the transformed source project and the transformed target project in the manifold space, and finally uses the transformed source project to train a naive Bayes prediction model with better performance. A comparative experiment was carried out using the Relink dataset and the AEEEM dataset. The experimental results show that compared with the benchmark method and several cross-project defect prediction methods, the proposed method effectively reduces the difference in data distribution between the source project and the target project, and obtains a higher F1 value, which is an indicator commonly used to measure the performance of the two-class model.
    Electronic ISSN: 1999-5903
    Topics: Computer Science
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2021-08-12
    Description: In this study, the sequential extraction method was applied to extract selected potentially toxic elements (PTEs) (Cd, Cr, Cu, Fe, Ni, Pb and Zn) in river sediments collected from the Blood River situated in Seshego area, Limpopo Province, South Africa. The study aimed to assess a possible trend of mobilisation of these elements from sediment to water. The accuracy of the sequential extraction method was confirmed by analysing sediment-certified reference material, and quantitative percentage recoveries ranging from 86 to 119%, 81 to 111% and 77 to 119% were achieved for exchangeable, reducible and oxidisable fractions, respectively. The potential risk of the PTEs in sediments was evaluated. The calculated values of contamination factor (CF) as well as risk assessment code (RAC) for Cd, Cu, Ni and Pb revealed the mobility of these elements. The PTEs in river sediments are at a high toxicity-risk level and could therefore cause a threat to organisms dwelling in sediments and humans via consumption of crops irrigated with the polluted river water.
    Electronic ISSN: 2075-163X
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2021-08-20
    Description: This paper discusses the performance of the short pitch-based carbon fiber reinforced mortar (CFRM) composite considering its key properties and cost-effectiveness. Five different types of mortar composite were produced using 0–4% volume contents of short pitch-based carbon fibers. The mortar composites were tested for inverted slump cone flow (flow time and volume flow), unit weight, air content, compressive strength, flexural strength, impact resistance, and water absorption. The cost-effectiveness of CFRM was assessed based on the performance to cost ratio (PCR), which was calculated for each mortar composite, considering its workability, mechanical properties, and durability. The inverted slump cone volume flow was counted as a measure of workability, whereas the compressive strength, flexural strength, and impact resistance were considered as the major attributes of the mechanical behavior. In addition, the water absorption was used as a measure of durability. The test results revealed that the mortar composite made with 3% carbon fibers provided adequate workability, a relatively high unit weight and low air content, the highest compressive strength, excellent flexural strength, good impact resistance, and the lowest water absorption. It was also found that the PCR increased up to 3% carbon fibers. Beyond a 3% fiber content, the PCR significantly decreased. The overall research findings revealed that the mortar with 3% carbon fibers was the optimum and most cost-effective mortar composite.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...