bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological Adaptation of River Channels to Vegetation Establishment: A Laboratory Study
Authors: Vargas‐Luna Andrés , Duró Gonzalo , Crosato Alessandra , Uijttewaal Wim 
Published: July 2019

AbstractWhile the scientific community has long recognized that alluvial rivers are the product of interactions between flowing water and bed material transport, it is increasingly evident that vegetation mediates these interactions and influences the stream channel characteristics. In a novel set of mobile bed laboratory experiments with variable discharge, we demonstrate that vegetation colonization affects bank erosion rates, channel shape, channel sinuosity, and bar pattern. Our analyses compared the morphological evolution of channels with initially steady bars considering the following three scenarios: (1) channel without vegetation, (2) channel with vegetation added to the floodplains, and (3) channel with vegetation added to both the floodplains and the bar surfaces that emerge at low flows. Absence of vegetation produced the widest and shallowest channel with the lowest sinuosity. Floodplain vegetation in the second scenario reduced bank erosion and resulted in a deeper and more sinuous channel with shorter bars. In the third scenario, vegetation establishment on emerging bar surfaces intensified erosion on the opposing bank, enlarging the amplitude of bends. Enhanced sedimentation on vegetated bar areas increased both bar elevation and bar length compared to the second scenario. The results show that the colonization of bar surfaces by plants creates the conditions for new floodplain and island formation, fostering channel meandering and anabranching. Finally, our experiments emphasize the role of alternating high and low flows on the morphological development of streams mediated by vegetation.
The Molecular Composition of Humic Substances Isolated From Yedoma Permafrost and Alas Cores in the Eastern Siberian Arctic as Measured by Ultrahigh Resolution Mass Spectrometry
Authors: Zherebker A. , Podgorski D. C. , Kholodov V. A. , Orlov A. A. , Yaroslavtseva N. V. , Kharybin O. , Kholodov A. , Spector V. , Spencer R. G. M. , Nikolaev E. , Perminova I. V. 
Published: July 2019

AbstractOngoing climate change is making the large pool of organic matter (OM) stored in Arctic permafrost vulnerable to mobilization; thus, garnering a deeper understanding of molecular transformations within the abundant pool of soil OM, specifically humic substances, is crucial. Here we present the first high‐resolution mass‐spectrometry examination of molecular compositions of humic acid (HA) and fulvic acid (FA) isolated from organic‐rich deep yedoma (Pleistocene age ice‐rich permafrost) and alas (thermokarst deposit formed during permafrost thaw) cores. The FA fractions were dominated by oxygen‐rich unsaturated compounds, whereas the HA fractions were mostly composed of relatively reduced saturated and aromatic moieties. A substantial increase in contribution of both CHO‐only and N‐containing aliphatic compounds was observed in the HA fractions of the yedoma OM with depth, whereas the alas HA fractions were depleted in aliphatics but enriched with condensed and hydrolyzable tannins. The observed differences in compositional space of the immobile OM stored in the deep yedoma versus alas deposits were consistent with evolution of OM during thermokarst lake genesis, implying intense microbial degradation of N‐rich OM released from the yedoma deposits and accumulation of highly degraded, plant‐derived OM. The patterns of molecular transformations of OM were apparent in compositional space of the least degraded HA fractions as compared to much more oxidized FA fractions. This shows great promise of molecular exploration of the alkali‐extracted OM, comprising up to 50% of the total organic carbon in deep permafrost both for paleoreconstructions and predictions of climate feedback to released OM due to permafrost thaw.
A New Perspective on Terrestrial Hydrologic Intensity That Incorporates Atmospheric Water Demand
Authors: Ficklin Darren L. , Abatzoglou John T. , Novick Kimberly A. 
Published: July 2019

AbstractHydrologic intensity is often quantified using precipitation without directly incorporating atmospheric water demand. We develop a hydrologic intensity index called the surplus deficit intensity (SDI) index that accounts for variation in supply and demand. SDI is the standardized sum of standardized surplus intensity (mean of daily surplus when supply > demand) and deficit time (mean of consecutive days when demand > supply). Using an observational ensemble of global daily precipitation and atmospheric water demand during 1979–2017, we document widespread hydrologic intensification (SDI; +0.11 z‐score per decade) driven primarily by increased surplus intensity. Using a climate model ensemble of the United States, hydrologic intensification is projected for the mid‐21st century (+0.86 in z‐score compared to 1971–2000), producing greater apparent intensification when compared to an index that does not explicitly incorporate demand. While incorporating demand had a minor effect on observed hydrologic intensification, it doubles hydrological intensification for the mid‐21st century.
Heat Flow in the Western Arctic Ocean (Amerasian Basin)
Authors: Ruppel C. D. , Lachenbruch A. H. , Hutchinson D. R. , Munroe R. J. , Mosher D. C. 
Published: July 2019

AbstractFrom 1963 to 1973 the U.S. Geological Survey measured heat flow at 356 sites in the Amerasian Basin (Western Arctic Ocean) from a drifting ice island (T‐3). The resulting measurements, which are unevenly distributed on Alpha‐Mendeleev Ridge and in Canada and Nautilus Basins, greatly expand available heat flow data for the Arctic Ocean. Average T‐3 heat flow is ~54.7 ± 11.3 mW/m2, and Nautilus Basin is the only well‐surveyed area (~13% of data) with significantly higher average heat flow (63.8 mW/m2). Heat flow and bathymetry are not correlated at a large scale, and turbiditic surficial sediments (Canada and Nautilus Basins) have higher heat flow than the sediments that blanket the Alpha‐Mendeleev Ridge. Thermal gradients are mostly near‐linear, implying that conductive heat transport dominates and that near‐seafloor sediments are in thermal equilibrium with overlying bottom waters. Combining the heat flow data with modern seismic imagery suggests that some of the observed heat flow variability may be explained by local changes in lithology or the presence of basement faults that channel circulating seawater. A numerical model that incorporates thermal conductivity variations along a profile from Canada Basin (thick sediment on mostly oceanic crust) to Alpha Ridge (thin sediment over thick magmatic units associated with the High Arctic Large Igneous Province) predicts heat flow slightly lower than that observed on Alpha Ridge. This, along with other observations, implies that circulating fluids modulate conductive heat flow and contribute to high variability in the T‐3 data set.
Characterizing the Self‐Potential Response to Concentration Gradients in Heterogeneous Subsurface Environments
Authors: MacAllister DJ. , Graham M. T. , Vinogradov J. , Butler A. P. , Jackson M. D. 
Published: July 2019

AbstractSelf‐potential (SP) measurements can be used to characterize and monitor, in real‐time, fluid movement and behavior in the subsurface. The electrochemical exclusion‐diffusion (EED) potential, one component of SP, arises when concentration gradients exist in porous media. Such concentration gradients are of concern in coastal and contaminated aquifers and oil and gas reservoirs. It is essential that estimates of EED potential are made prior to conducting SP investigations in complex environments with heterogeneous geology and salinity contrasts, such as the UK Chalk coastal aquifer. Here we report repeatable laboratory estimates of the EED potential of chalk and marls using natural groundwater (GW), seawater (SW), deionized (DI) water, and 5 M NaCl. In all cases, the EED potential of chalk was positive (using a GW/SW concentration gradient the EED potential was ca. 14 to 22 mV), with an increased deviation from the diffusion limit at the higher salinity contrast. Despite the relatively small pore size of chalk (ca. 1 μm), it is dominated by the diffusion potential and has a low exclusion efficiency, even at large salinity contrasts. Marl samples have a higher exclusion efficiency which is of sufficient magnitude to reverse the polarity of the EED potential (using a GW/SW concentration gradient the EED potential was ca. −7 to −12 mV) with respect to the chalk samples. Despite the complexity of the natural samples used, the method produced repeatable results. We also show that first order estimates of the exclusion efficiency can be made using SP logs, supporting the parameterization of the model reported in Graham et al. (2018, https://doi.org/10.1029/2018WR022972), and that derived values for marls are consistent with the laboratory experiments, while values derived for hardgrounds based on field data indicate a similarly high exclusion efficiency. While this method shows promise in the absence of laboratory measurements, more rigorous estimates should be made where possible and can be conducted following the experimental methodology reported here.
The molecular nature of the 17β-Estradiol binding site in the voltage- and Ca2+-activated K+ (BK) channel β1 subunit
Authors: Granados Sara T. , Castillo Karen , Bravo-Moraga Felipe , Sepúlveda Romina V. , Carrasquel-Ursulaez Willy , Rojas Maximiliano , Carmona Emerson , Lorenzo-Ceballos Yenisleidy , González-Nilo Fernando , González Carlos , Latorre Ramón , Torres Yolima P. 
Published: July 2019

AbstractThe accessory β1 subunit modulates the Ca2+- and voltage-activated K+ (BK) channel gating properties mainly by increasing its apparent Ca2+ sensitivity. β1 plays an important role in the modulation of arterial tone and blood pressure by vascular smooth muscle cells (SMCs). 17β-estradiol (E2) increases the BK channel open probability (Po) in SMCs, through a β1 subunit-dependent modulatory effect. Here, using molecular modeling, bioinformatics, mutagenesis, and electrophysiology, we identify a cluster of hydrophobic residues in the second transmembrane domain of the β1 subunit, including the residues W163 and F166, as the binding site for E2. We further show that the increase in Po induced by E2 is associated with a stabilization of the voltage sensor in its active configuration and an increase in the coupling between the voltage sensor activation and pore opening. Since β1 is a key molecular player in vasoregulation, the findings reported here are of importance in the design of novel drugs able to modulate BK channels.
Neural Correlates of Variations in Human Trust in Human-like Machines during Non-reciprocal Interactions
Authors: Jung Eun-Soo , Dong Suh-Yeon , Lee Soo-Young 
Published: July 2019

AbstractAs intelligent machines have become widespread in various applications, it has become increasingly important to operate them efficiently. Monitoring human operators’ trust is required for productive interactions between humans and machines. However, neurocognitive understanding of human trust in machines is limited. In this study, we analysed human behaviours and electroencephalograms (EEGs) obtained during non-reciprocal human-machine interactions. Human subjects supervised their partner agents by monitoring and intervening in the agents’ actions in this non-reciprocal interaction, which reflected practical uses of autonomous or smart systems. Furthermore, we diversified the agents with external and internal human-like factors to understand the influence of anthropomorphism of machine agents. Agents’ internal human-likenesses were manifested in the way they conducted a task and affected subjects’ trust levels. From EEG analysis, we could define brain responses correlated with increase and decrease of trust. The effects of trust variations on brain responses were more pronounced with agents who were externally closer to humans and who elicited greater trust from the subjects. This research provides a theoretical basis for modelling human neural activities indicate trust in partner machines and can thereby contribute to the design of machines to promote efficient interactions with humans.
Statistical model choice including variable selection based on variable importance: A relevant way for biomarkers selection to predict meat tenderness
Authors: Ellies-Oury M. P. , Chavent M. , Conanec A. , Bonnet M. , Picard B. , Saracco J. 
Published: July 2019

AbstractIn this paper, we describe a new computational methodology to select the best regression model to predict a numerical variable of interest Y and to select simultaneously the most interesting numerical explanatory variables strongly linked to Y. Three regression models (parametric, semi-parametric and non-parametric) are considered and estimated by multiple linear regression, sliced inverse regression and random forests. Both the variables selection and the model choice are computational. A measure of importance based on random perturbations is calculated for each covariate. The variables above a threshold are selected. Then a learning/test samples approach is used to estimate the Mean Square Error and to determine which model (including variable selection) is the most accurate. The R package modvarsel (MODel and VARiable SELection) implements this computational approach and applies to any regression datasets. After checking the good behavior of the methodology on simulated data, the R package is used to select the proteins predictive of meat tenderness among a pool of 21 candidate proteins assayed in semitendinosus muscle from 71 young bulls. The biomarkers were selected by linear regression (the best regression model) to predict meat tenderness. These biomarkers, we confirm the predominant role of heat shock proteins and metabolic ones.
Predicted Impact of Climate Change on Trihalomethanes Formation in Drinking Water Treatment
Authors: Valdivia-Garcia Maria , Weir Paul , Graham David W. , Werner David 
Published: July 2019

AbstractQuantitative predictions of impacts on public water supplies are essential for planning climate change adaptations. Monitoring data from five full-scale Scottish drinking water treatment plants (DWTPs) showed that significant correlations exist between conditionally carcinogenic trihalomethanes (THMs) levels, water temperature (r = 0.812, p = 0.0013) and dissolved organic carbon (DOC) (r = 0.892, p < 0.0001), respectively. The strong seasonality of these parameters demonstrated how climate can influence THMs formation. We quantified with laboratory experiments the sensitivity of THMs formation to changes in water temperature and DOC concentration. The laboratory data accurately reproduced real-world THM formation in the DWTPs. We then combined these validated relationships with information from the literature about future trends in mean summer temperatures and surface water DOC in the British Isles, to estimate future global warming impacts on THMs formation in DWTPs that use chlorine for disinfection. An increase in mean summer temperatures will likely increase THM formation, with a 1.8 °C temperature increase and 39% THMs increase by 2050 representing our mid-range scenario. Such an increase has major implications to potable water around the world, either an increased health risk or increased water treatment costs to maintain an equivalent quality potable supply.
Preparation of the heterojunction catalyst N-doping carbon quantum dots/P25 and its visible light photocatalytic activity
Authors: Xu Ning , Huang Hongqin , Ouyang Hao , Wang Huigang 
Published: July 2019

AbstractN-doping carbon quantum dots were successfully loaded on P25 nanoparticles (denoted as N-CDs/P25) by facile hydrothermal process, and their morphology and chemical structure were systematically studied. The carrier of N-CDs can significantly broaden the photoresponse range of the P25 to the visible region, accelerate charge transportation and separation. Application of the N-CDs/P25 material for the photocatalytic decomposition of Rhodamine B (RhB) gave improved activity relative to P25. The best degradation activity obtained at 6mL N-CDs/P25 under visible light irradiation, which shows a 13.06 fold photocatalytic activity over P25. Radical trapping control experiment and Electron Paramagnetic Resonance (EPR) measurements have been applied to explore the photodegradation dynamic and visible-light driven degradation mechanism. This work provides new insights into the fabrication of N-doping carbon quantum dots/TiO2 composite and is promising to open new possibilities in the application of carbon-TiO2 composites as the photocatalysts in the environmental protection issues.
Identifying candidate genes for Phytophthora capsici resistance in pepper (Capsicum annuum) via genotyping-by-sequencing-based QTL mapping and genome-wide association study
Authors: Siddique Muhammad Irfan , Lee Hea-Young , Ro Na-Young , Han Koeun , Venkatesh Jelli , Solomon Abate Mekonnen , Patil Abhinandan Surgonda , Changkwian Amornrat , Kwon Jin-Kyung , Kang Byoung-Cheorl 
Published: July 2019

AbstractPhytophthora capsici (Leon.) is a globally prevalent, devastating oomycete pathogen that causes root rot in pepper (Capsicum annuum). Several studies have identified quantitative trait loci (QTL) underlying resistance to P. capsici root rot (PcRR). However, breeding for pepper cultivars resistant to PcRR remains challenging due to the complexity of PcRR resistance. Here, we combined traditional QTL mapping with GWAS to broaden our understanding of PcRR resistance in pepper. Three major-effect loci (5.1, 5.2, and 5.3) conferring broad-spectrum resistance to three isolates of P. capsici were mapped to pepper chromosome P5. In addition, QTLs with epistatic interactions and minor effects specific to isolate and environment were detected on other chromosomes. GWAS detected 117 significant SNPs across the genome associated with PcRR resistance, including SNPs on chromosomes P5, P7, and P11 that colocalized with the QTLs identified here and in previous studies. Clusters of candidate nucleotide-binding site-leucine-rich repeat (NBS-LRR) and receptor-like kinase (RLK) genes were predicted within the QTL and GWAS regions; such genes often function in disease resistance. These candidate genes lay the foundation for the molecular dissection of PcRR resistance. SNP markers associated with QTLs for PcRR resistance will be useful for marker-assisted breeding and genomic selection in pepper breeding.
Superlattice in collapsed graphene wrinkles
Authors: Verhagen Tim , Pacakova Barbara , Bousa Milan , Hübner Uwe , Kalbac Martin , Vejpravova Jana , Frank Otakar 
Published: July 2019

AbstractTopographic corrugations, such as wrinkles, are known to introduce diverse physical phenomena that can significantly modify the electrical, optical and chemical properties of two-dimensional materials. This range of assets can be expanded even further when the crystal lattices of the walls of the wrinkle are aligned and form a superlattice, thereby creating a high aspect ratio analogue of a twisted bilayer or multilayer – the so-called twisted wrinkle. Here we present an experimental proof that such twisted wrinkles exist in graphene monolayers on the scale of several micrometres. Combining atomic force microscopy and Raman spectral mapping using a wide range of visible excitation energies, we show that the wrinkles are extremely narrow and their Raman spectra exhibit all the characteristic features of twisted bilayer or multilayer graphene. In light of a recent breakthrough – the superconductivity of a magic-angle graphene bilayer, the collapsed wrinkles represent naturally occurring systems with tuneable collective regimes.
Defaunation of large-bodied frugivores reduces carbon storage in a tropical forest of Southeast Asia
Authors: Chanthorn Wirong , Hartig Florian , Brockelman Warren Y. , Srisang Wacharapong , Nathalang Anuttara , Santon Jantima 
Published: July 2019

AbstractRecent studies have suggested that defaunation of large-bodied frugivores reduces above-ground carbon storage in tropical forests of South America and Africa, but not, or less so, in Southeast Asian tropical forests. Here we analyze the issue using the seed dispersal network (data of interaction between trees and animal seed dispersers) and forest composition of a 30-ha forest dynamics plot in central Thailand, where an intact fauna of primates, ungulates, bears and birds of all sizes still exists. We simulate the effect of two defaunation scenarios on forest biomass: 1) only primates extirpated (a realistic possibility in near future), and 2) extirpation of all large-bodied frugivores (LBF) including gibbons, macaques, hornbills and terrestrial mammals, the main targets of poachers in this region. For each scenario, we varied the population size reduction of the LBF dispersed tree species from 20% to 100%. We find that tree species dependent on seed dispersal by large-bodied frugivores (LBF) account for nearly one-third of the total carbon biomass on the plot, and that the community turnover following a complete defaunation would result in a carbon reduction of 2.4% to 3.0%, depending on the defaunation scenario and the model assumptions. The reduction was always greater than 1% when the defaunation intensity was at least 40%. These effect sizes are comparable to values reported for Neotropical forests, suggesting that the impact of defaunation on carbon deficit is not necessarily lower in Southeast Asian forests. The problem of defaunation in Asia, and the mutual benefits between biodiversity conservation and climate change mitigation, should therefore not be neglected by global policies to reduce carbon emissions.
Precursor RNA processing 3 is required for male fertility, and germline stem cell self-renewal and differentiation via regulating spliceosome function in Drosophila testes
Authors: Chen Xia , Luan Xiaojin , Zheng Qianwen , Qiao Chen , Chen Wanyin , Wang Min , Yan Yidan , Xie Bing , Shen Cong , He Zeyu , Zhang Jun , Liu Mingxi , Hu Xing , Li Hong , Zheng Bo , Fang Jie , Yu Jun 
Published: July 2019

AbstractThe nuclear pre-mRNA spliceosome is a large complex containing five small nuclear ribonucleoprotein particles (snRNPs) and many splicing factors. Messenger RNAs (mRNAs) are generated from pre-mRNAs by the process of RNA splicing, which is conserved in eukaryotes. Precursor RNA processing 3 (Prp3) is a U4/U6-associated snRNP whose function remains largely unknown. In the present study, using genetic manipulation of aDrosophila melanogastertestis model, we demonstrated thatPrp3is essential for male fertility inDrosophila.Prp3deficiency in germline stem cells (GSCs) and early cyst cells resulted in abnormal structure of testes and maintenance defects of GSCs and cyst stem cells. Knockdown ofPrp3in spermatogonia and early cyst cells mediated tumor formation caused by differentiation defects. Using anin vitroassay, knockdown ofPrp3decreased proliferation and increased cell death, and controlled the spliceosome function via regulating spliceosome subunits expression inDrosophilaS2 cells. We also identified two other splicing factors in the Prp complex (Prp19andPrp8), which mimicked the phenotype ofPrp3in theDrosophilastem cell niche. Our results revealed a significant role of precursor RNA processing factors in male testes, indicating that Prp3, a key spliceosome component in the Prp complex, is essential for male fertility, and germline stem cell self-renewal and differentiation, via regulating the spliceosome function inDrosophilatestes.