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  • Articles  (64)
  • Wiley  (36)
  • Copernicus  (20)
  • Frontiers Media  (8)
  • Biology  (35)
  • Geosciences  (25)
  • Geography  (19)
  • Nature of Science, Research, Systems of Higher Education, Museum Science
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  • Articles  (64)
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  • 1
    Publication Date: 2012-04-16
    Description: The nuclear positioning of mammalian genes often correlates with their functional state. For instance, the human cystic fibrosis transmembrane conductance regulator (CFTR) gene associates with the nuclear periphery in its inactive state, but occupies interior positions when active. It is not understood how nuclear gene positioning is determined. Here, we investigated trichostatin A (TSA)-induced repositioning of CFTR in order to address molecular mechanisms controlling gene positioning. Treatment with the histone deacetylase (HDAC) inhibitor TSA induced increased histone acetylation and CFTR repositioning towards the interior within 20 minutes. When CFTR localized in the nuclear interior (either after TSA treatment or when the gene was active) consistent histone H3 hyperacetylation was observed at a CTCF site close to the CFTR promoter. Knockdown experiments revealed that CTCF was essential for perinuclear CFTR positioning and both, CTCF knockdown as well as TSA treatment had similar and CFTR-specific effects on radial positioning. Furthermore, knockdown experiments revealed that also A-type lamins were required for the perinuclear positioning of CFTR. Together, the results showed that CTCF, A-type lamins and an active HDAC were essential for perinuclear positioning of CFTR and these components acted on a CTCF site adjacent to the CFTR promoter. The results are consistent with the idea that CTCF bound close to the CFTR promoter, A-type lamins and an active HDAC form a complex at the nuclear periphery, which becomes disrupted upon inhibition of the HDAC, leading to the observed release of CFTR. J. Cell. Biochem. © 2012 Wiley Periodicals, Inc.
    Electronic ISSN: 0091-7419
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Published by Wiley
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  • 2
    Publication Date: 2014-10-10
    Description: Weather generators are used for spatio-temporal downscaling of climate model outputs (e.g., precipitation and temperature) to investigate the impact of climate change on the hydrological cycle. In this study, a multiplicative random cascade model is proposed for the stochastic temporal disaggregation of monthly to daily precipitation fields, which is designed to be applicable to grids of any spatial resolution and extent. The proposed method uses stationary distribution functions that describe the partitioning of precipitation throughout multiple temporal scales (e.g., weekly and bi-weekly scale). Moreover, it explicitly considers the intensity and spatial covariance of precipitation in the disaggregation procedure, but requires no assumption about the temporal relationship and spatial isotropy of precipitation fields. A split sampling test is conducted on a high-resolution (i.e., 4×4 km 2 grid) daily precipitation data set over Germany (≈ 357 000 km 2 ) to assess the performance of the proposed method during future periods. The proposed method has proven to consistently reproduce distinctive location dependent precipitation distribution functions with biases less than 5% during both a calibration and evaluation period. Furthermore, extreme precipitation amounts and the spatial and temporal covariance of the generated fields are comparable to those of the observations. Consequently, the proposed temporal disaggregation approach satisfies the minimum conditions for a precipitation generator aiming at the assessment of hydrological response to climate change at regional and continental scales or for generating seamless predictions of hydrological variables.
    Print ISSN: 0043-1397
    Electronic ISSN: 1944-7973
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 3
    Publication Date: 2016-10-28
    Description: ABSTRACT Branched glycerol dialkyl glycerol tetraethers (brGDGTs) were abundant in surface sediments of freshwater lakes and in catchment soils at altitudes from 10 to 2020 m in New Zealand. Significant differences in brGDGT compositions between lake sediments and soils indicate sources from separate microbial habitats. An expanded modern calibration dataset comprising 33 lakes has enabled a revised calibration function for determining past m ean a nnual air t emperature (MAT) from brGDGTs in New Zealand lake sediments: MAT (°C) = −31.664 × MBT m  + 16.252 ( n  = 30). The function uses a modified methylation index of branched tetraethers (MBT m ) that incorporates brGDGT III in the numerator to overcome the lower correlation found between our larger dataset and the unmodified MBT which had been used for previous calibrations. Calibrations combining the cyclization index of branched tetraethers (CBT) and the MBT m or using only certain brGDGTs are possible but have limitations. The revised function shows slightly higher correlation with MAT ( R 2  = 0.75) than previous calibrations, which were based on nine sites. The refined calibration function is applied to a ∼16 000-year lake sediment sequence from northern South Island, New Zealand, and yields temperature reconstructions that are consistent with independently derived climate trends from the same sequence.
    Print ISSN: 0267-8179
    Electronic ISSN: 1099-1417
    Topics: Geography , Geosciences
    Published by Wiley
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  • 4
    Publication Date: 2017-04-29
    Description: Global human population growth is associated with many problems, such as food and water provision, political conflicts, spread of diseases and environmental destruction. The mitigation of these problems is mirrored in several global conventions and programs, some of which however are conflicting. Here we discuss the conflicts between biodiversity conservation and disease eradication. Numerous health programs aim at eradicating pathogens, and many focus on the eradication of vectors, such as mosquitos or other parasites. As a case study, we focus on the ‘Pan African Tsetse and Trypanosomiasis Eradication Campaign’ (PATTEC), which aims at eradicating a pathogen ( Trypanosoma ) as well as its vector, the entire group of tsetse flies (Glossinidae). As the distribution of tsetse flies largely overlaps with the African hotspots of freshwater biodiversity, we argue for a strong consideration of environmental issues when applying vector control measures, especially the aerial applications of insecticides. Furthermore, we want to stimulate discussions on the value of species and whether full eradication of a pathogen or vector is justified at all. Finally, we call for a stronger harmonization of international conventions. Proper environmental impact assessments need to be conducted before control or eradication programmes are carried out to minimize negative effects on biodiversity. This article is protected by copyright. All rights reserved
    Print ISSN: 1755-263X
    Electronic ISSN: 1755-263X
    Topics: Biology
    Published by Wiley on behalf of The Society for Conservation Biology.
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  • 5
    Publication Date: 2015-11-07
    Description: The Pleistocene was characterized by worldwide shifts in community compositions. Some of these shifts were a result of changes in fire regimes, which influenced the distribution of species belonging to fire-dependent communities. We studied an endangered juniper–oak shrubland specialist, the black-capped vireo ( Vireo atricapilla ). This species was locally extirpated in parts of Texas and Oklahoma by the end of the 1980s as a result of habitat change and loss, predation, brood parasitism, and anthropogenic fire suppression. We sequenced multiple nuclear loci and used coalescence methods to obtain a deeper understanding of historical population trends than that typically available from microsatellites or mtDNA. We compared our estimated population history, a long-term history of the fire regime and ecological niche models representing the mid-Holocene, last glacial maximum, and last interglacial. Our Bayesian skyline plots showed a pattern of historical population fluctuation that was consistent with changing fire regimes. Genetic data suggest that the species is genetically unstructured, and that the current population should be orders of magnitude larger than it is at present. We suggest that fire suppression and habitat loss are primary factors contributing to the recent decline of the BCVI, although the role of climate change since the last glacial maximum is unclear at present. We used DNA sequences from multiple nuclear loci to investigate the long-term population history of the black-capped vireo. We found that population fluctuations are correlated with changes in the fire regime that affects the extent of the species habitat. The data suggest that BCVIs could be much more abundant than they are at present, owing likely to fire suppression and other anthropogenic influences on habitat extent.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley
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  • 6
    Publication Date: 2015-07-22
    Description: Environmental models tend to require increasing computational time and resources as physical process descriptions are improved or new descriptions are incorporated. Many-query applications such as sensitivity analysis or model calibration usually require a large number of model evaluations leading to high computational demand. This often limits the feasibility of rigorous analyses. Here we present a fully automated sequential screening method that selects only informative parameters for a given model output. The method requires a number of model evaluations that is approximately ten times the number of model parameters. It was tested using the mesoscale hydrologic model mHM in three hydrologically unique European river catchments. It identified around 20 informative parameters out of 52, with different informative parameters in each catchment. The screening method was evaluated with subsequent analyses using all 52 as well as only the informative parameters. Subsequent Sobol's global sensitivity analysis led to almost identical results yet required 40\% fewer model evaluations after screening. mHM was calibrated with all and with only informative parameters in the three catchments. Model performances for daily discharge were equally high in both cases with Nash-Sutcliffe efficiencies above 0.82. Calibration using only the informative parameters needed just one third of the number of model evaluations. The universality of the sequential screening method was demonstrated using several general test functions from the literature. We therefore recommend the use of the computationally inexpensive sequential screening method prior to rigorous analyses on complex environmental models. This article is protected by copyright. All rights reserved.
    Print ISSN: 0043-1397
    Electronic ISSN: 1944-7973
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 7
    Publication Date: 2017-05-26
    Description: We report on the first observations of 100 eV to 100 keV electrons over the auroral regions of Jupiter by the Jovian Auroral Distributions Experiment (JADE) onboard the Juno mission. The focus is on the regions that were magnetically connected to the main auroral oval. Amongst the most remarkable features, JADE observed electron beams, mostly upward going but also some downward going in the south, at latitudes from ~69° to 72° and ~ −66° to −70° corresponding to M-shells (“M” for magnetic) from ~18 to 54 and ~28 to 61, respectively. The beams were replaced by upward loss cones at lower latitudes. There was no evidence of strongly accelerated downward electrons analogous to the auroral “inverted V's” at Earth. Rather, the presence of upward loss cones suggests a diffuse aurora process. The energy spectra resemble tails of distributions or power laws (suggestive of a stochastic acceleration process), but can also have some clear enhancements or even peaks generally between 1 and 10 keV. Electron intensities change on time scales of a second or less at times implying that auroral structures can be of the order of a few tens of km.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 8
    Publication Date: 2017-05-26
    Description: Using Juno plasma and wave and magnetic observations (JADE and Waves and MAG instruments), the generation mechanism of the Jovian hectometric radio emission is analyzed. It is shown that suitable conditions for the cyclotron maser instability (CMI) are observed in the regions of the radio sources. Pronounced loss cone in the electron distributions are likely the source of free energy for the instability. The theory reveals that sufficient growth rates are obtained from the distribution functions that are measured by the JADE-Electron instrument. The CMI would be driven by upgoing electron populations at 5–10 keV and 10–30° pitch angle, the amplified waves propagating at 82°–87° from the B field, a fraction of a percent above the gyrofrequency. Typical e -folding times of 10 −4  s are obtained, leading to an amplification path of ~1000 km. Overall, this scenario for generation of the Jovian hectometric waves differs significantly from the case of the auroral kilometric radiation at Earth.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 9
    Publication Date: 2010-09-01
    Print ISSN: 0361-5995
    Electronic ISSN: 1435-0661
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Wiley
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  • 10
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