bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Analytical Bond Order Potential for Mg−H Systems
Authors: Zhou Xiaowang , Kang Shinyoung , Heo Tae Wook , Wood Brandon C. , Stavila Vitalie , Allendorf Mark D. 
Published: January 2019

AbstractMagnesium‐based materials provide some of the highest capacities for solid‐state hydrogen storage. However, efforts to improve their performance rely on a comprehensive understanding of thermodynamic and kinetic limitations at various stages of (de)hydrogenation. Part of the complexity arises from the fact that unlike interstitial metal hydrides that retain the same crystal structures of the underlying metals, MgH2 and other magnesium‐based hydrides typically undergo dehydrogenation reactions that are coupled to a structural phase transformation. As a first step towards enabling molecular dynamics studies of thermodynamics, kinetics, and (de)hydrogenation mechanisms of Mg‐based solid‐state hydrogen storage materials with changing crystal structures, we have developed an analytical bond order potential for Mg−H systems. We demonstrate that our potential accurately reproduces property trends of a variety of elemental and compound configurations with different coordinations, including small clusters and bulk lattices. More importantly, we show that our potential captures the relevant (de)hydrogenation chemical reactions 2H (gas)→H2 (gas) and 2H (gas)+Mg (hcp)→MgH2 (rutile) within molecular dynamics simulations. This verifies that our potential correctly prescribes the lowest Gibbs free energies to the equilibrium H2 and MgH2 phases as compared to other configurations. It also indicates that our molecular dynamics methods can directly reveal atomic processes of (de)hydrogenation of the Mg−H systems.
Assessing eukaryotic biodiversity in the Florida Keys National Marine Sanctuary through environmental DNA metabarcoding
Authors: Sawaya Natalie A. , Djurhuus Anni , Closek Collin J. , Hepner Megan , Olesin Emily , Visser Lindsey , Kelble Christopher , Hubbard Katherine , Breitbart Mya 
Published: January 2019

AbstractEnvironmental DNA (eDNA) is the DNA suspended in the environment (e.g., water column), which includes cells, gametes, and other material derived from but not limited to shedding of tissue, scales, mucus, and fecal matter. Amplifying and sequencing marker genes (i.e., metabarcoding) from eDNA can reveal the wide range of taxa present in an ecosystem through analysis of a single water sample. Metabarcoding of eDNA provides higher resolution data than visual surveys, aiding in assessments of ecosystem health. This study conducted eDNA metabarcoding of two molecular markers (cytochrome c oxidase I (COI) and 18S ribosomal RNA (rRNA) genes) to survey eukaryotic diversity across multiple trophic levels in surface water samples collected at three sites along the coral reef tract within the Florida Keys National Marine Sanctuary (FKNMS) during four research cruises in 2015. The 18S rRNA gene sequences recovered 785 genera while the COI gene sequences recovered 115 genera, with only 33 genera shared between the two datasets, emphasizing the complementarity of these marker genes. Community composition for both genetic markers clustered by month of sample collection, suggesting that temporal variation has a larger effect on biodiversity than spatial variability in the FKNMS surface waters. Sequences from both marker genes were dominated by copepods, but each marker recovered distinct phytoplankton groups, with 18S rRNA gene sequences dominated by dinoflagellates and COI sequences dominated by coccolithophores. Although eDNA samples were collected from surface waters, many benthic species such as sponges, crustaceans, and corals were identified. These results show the utility of eDNA metabarcoding for cataloging biodiversity to establish an ecosystem baseline against which future samples can be compared in order to monitor community changes.
The integrative effects of behavior and morphology on amphibian movement
Authors: Bredeweg Evan M. , Morzillo Anita T. , Thurman Lindsey L. , Garcia Tiffany S. 
Published: January 2019

AbstractAnimal movement and dispersal are key factors in population dynamics and support complex ecosystem processes like cross‐boundary subsidies. Juvenile dispersal is an important mechanism for many species and often involves navigation in unfamiliar habitats. For species that metamorphose, such as amphibians, this transition from aquatic to terrestrial environments involves the growth and use of new morphological traits (e.g., legs). These traits strongly impact the fundamental ability of an organism to move in novel landscapes, but innate behaviors can regulate choices that result in the realized movements expressed. By assessing the integrative role of morphology and behavior, we can improve our understanding of juvenile movement, particularly in understudied organisms like amphibians. We assessed the roles of morphological (snout‐vent length and relative leg length) and performance (maximal jump distance) traits in shaping the free movement paths, measured through fluorescent powder tracking, in three anuran species, Pacific treefrog (Hyliola regilla), Western toad (Anaxyrus boreas), and Cascades frog (Rana cascadae). We standardized the measurement of these traits to compare the relative role of species' innate differences versus physical traits in shaping movement. Innate differences, captured by species identity, were the most significant factor influencing movement paths via total movement distance and path sinuosity. Relative leg length was an important contributor but significantly interacted with species identity. Maximal jump performance, which was significantly predicted by morphological traits, was not an important factor in movement behavior relative to species identity. The importance of species identity and associated behavioral differences in realized movement provide evidence for inherent species differences being central to the dispersal and movement of these species. This behavior may stem from niche partitioning of these sympatric species, yet it also calls into question assumptions generalizing anuran movement behavior. These species‐level effects are important in framing differences as past research is applied in management planning.
Multiple facets of stream macroinvertebrate alpha diversity are driven by different ecological factors across an extensive altitudinal gradient
Authors: Li Zhengfei , Jiang Xiaoming , Wang Jun , Meng Xingliang , Heino Jani , Xie Zhicai 
Published: January 2019

AbstractEnvironmental filtering and spatial structuring are important ecological processes for the generation and maintenance of biodiversity. However, the relative importance of these ecological drivers for multiple facets of diversity is still poorly understood in highland streams. Here, we examined the responses of three facets of stream macroinvertebrate alpha diversity to local environmental, landscape‐climate and spatial factors in a near‐pristine highland riverine ecosystem. Taxonomic (species richness, Shannon diversity, and evenness), functional (functional richness, evenness, divergence, and Rao's Quadratic entropy), and a proxy of phylogenetic alpha diversity (taxonomic distinctness and variation in taxonomic distinctness) were calculated for macroinvertebrate assemblages in 55 stream sites. Then Pearson correlation coefficient was used to explore congruence of indices within and across the three diversity facets. Finally, multiple linear regression models and variation partitioning were employed to identify the relative importance of different ecological drivers of biodiversity. We found most correlations between the diversity indices within the same facet, and between functional richness and species richness were relatively strong. The two phylogenetic diversity indices were quite independent from taxonomic diversity but correlated with functional diversity indices to some extent. Taxonomic and functional diversity were more strongly determined by environmental variables, while phylogenetic diversity was better explained by spatial factors. In terms of environmental variables, habitat‐scale variables describing habitat complexity and water physical features played the primary role in determining the diversity patterns of all three facets, whereas landscape factors appeared less influential. Our findings indicated that both environmental and spatial factors are important ecological drivers for biodiversity patterns of macroinvertebrates in Tibetan streams, although their relative importance was contingent on different facets of diversity. Such findings verified the complementary roles of taxonomic, functional and phylogenetic diversity, and highlighted the importance of comprehensively considering multiple ecological drivers for different facets of diversity in biodiversity assessment.
Ecological drift and competitive interactions predict unique patterns in temporal fluctuations of population size
Authors: Ulrich Werner , Puchałka Radosław , Koprowski Marcin , Strona Giovanni , Gotelli Nicholas J. 
Published: January 2019

AbstractRecent studies have highlighted the importance of higher‐order competitive interactions in stabilizing population dynamics in multi‐species communities. But how does the structure of competitive hierarchies affect population dynamics and extinction processes? We tackled this important question by using spatially explicit simulations of ecological drift (10 species in a homogeneous landscape of 64 patches) in which birth rates were influenced by interspecific competition. Specifically, we examined how transitive (linear pecking orders) and intransitive (pecking orders with loops) competitive hierarchies affected extinction rates and population dynamics in simulated communities through time. In comparison to a pure neutral model, an ecological drift model including transitive competition increased extinction rates, caused synchronous density‐dependent population fluctuations, and generated a white‐noise distribution of population sizes. In contrast, the drift model with intransitive competitive interactions decreased extinctions rates, caused asynchronous (compensatory) density‐dependent population fluctuations, and generated a brown noise distribution of population sizes. We also explored the effect on community stability of more complex patterns of competitive interactions in which pairwise competitive relationships were assigned probabilistically. These probabilistic competition models also generated density‐dependent trajectories and a brown noise distribution of population sizes. However, extinction rates and the degree of population synchrony were comparable to those observed in purely neutral communities. Collectively, our results confirm that intransitive competition has a strong and stabilizing effect on local populations in species‐poor communities. This effect wanes with increasing species richness. Empirical assemblages characterized by brown spectral noise, density‐dependent regulation, and asynchronous (compensatory) population fluctuations may indicate a signature of intransitive competitive interactions.
Increasing water availability and facilitation weaken biodiversity–biomass relationships in shrublands
Authors: Guo Yanpei , Schöb Christian , Ma Wenhong , Mohammat Anwar , Liu Hongyan , Yu Shunli , Jiang Youxu , Schmid Bernhard , Tang Zhiyao 
Published: January 2019

AbstractPositive biodiversity–ecosystem‐functioning (BEF) relationships are commonly found in experimental and observational studies, but how they vary in different environmental contexts and under the influence of coexisting life forms is still controversial. Investigating these variations is important for making predictions regarding the dynamics of plant communities and carbon pools under global change. We conducted this study across 433 shrubland sites in northern China. We fitted structural equation models (SEMs) to analyze the variation in the species‐richness–biomass relationships of shrubs and herbs along a wetness gradient and general liner models (GLMs) to analyze how shrub or herb biomass affected the species‐richness–biomass relationship of the other life form. We found that the positive species‐richness–biomass relationships for both shrubs and herbs became weaker or even negative with higher water availability, likely indicating stronger interspecific competition within life forms under more benign conditions. After accounting for variation in environmental contexts using residual regression, we found that the benign effect of greater facilitation by a larger shrub biomass reduced the positive species‐richness–biomass relationships of herbs, causing them to become nonsignificant. Different levels of herb biomass, however, did not change the species‐richness–biomass relationship of shrubs, possibly because greater herb biomass did not alter the stress level for shrubs. We conclude that biodiversity in the studied plant communities is particularly important for plant biomass production under arid conditions and that it might be possible to use shrubs as nurse plants to facilitate understory herb establishment in ecological restoration.
Towards an evidence base on the value of social learning‐oriented approaches in the context of climate change and food security
Authors: Van Epp Marissa , Garside Ben 
Published: January 2019

AbstractAttention to social learning's potential to improve development outcomes in the context of climate change and food security challenges is growing. Yet evidence supporting the wide range of assertions about the outcomes of social learning processes is insufficient. More work is needed to understand when and how a social learning‐oriented approach is effective. We respond to the gap in evidence by piloting the Climate Change and Social Learning initiative's monitoring and evaluation framework for social learning. Our objectives are to begin building an evidence base and to test the theory of change behind the framework. Using a peer‐assist approach, we apply the framework to eight case studies in partnership with five initiatives. We analyse trends in evidence gathered across the case studies in four dimensions of social learning (engagement, iterative learning, capacity development, and challenging institutions) along three dimensions of change (process, learning outcomes, and changes in values and practice).
Carbon Paste Composite with Co3O4 as a New Electrochemical Sensor for the Detection of Allura Red by Reduction
Authors: Penagos‐Llanos Johisner , García‐Beltrán Olimpo , Calderón J. A. , Nagles Edgar , Hurtado J. J. 
Published: January 2019

AbstractThe detection of Allura red (AR) by electrochemical reduction using a different electrode from the conventional mercury electrode is presented. A carbon paste with cobalt (II, III) oxide composite electrode (CoOx/CPE) is reported for the first time for the detection of AR. Moreover, others dyes such as tartrazine (TZ), sunset yellow (SY), amaranth (AM), Ponceaut 4‐R (P‐4R), and Sudan (SD) as well as pharmaceutical agents such as paracetamol (PMC) that are present in samples that contained AR did not show a reduced signal between 0.0 and −0.3 V, which is the potential range where AR reduction was observed. The surface electroactivity was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The presence of CoOX increased the cathodic peak current for AR by more than 50 % and 65 % via CV and square wave voltammetry (SWV), respectively, compared with an unmodified carbon paste electrode. Under the optimal parameters, (pH=3.0, accumulation time (tACC)=60 s and accumulation potential (EACC)=0.50 V), the detection limit for AR was 0.05 μmol L−1. The new sensor was sensitive and stable for the detection of AR. Moreover, it was easily manufactured and very convenient for food samples such as soft and isotonic drinks as well as chili sauce.
Methane adsorption constrained by pore structure in high‐rank coals using FESEM, CO2 adsorption, and NMRC techniques
Authors: Yin Tingting , Liu Dameng , Cai Yidong , Zhou Yingfang 
Published: January 2019

AbstractTo evaluate the impacts of nanopores of high‐rank coals on coalbed methane adsorption and storage, 12 anthracite and semianthracite coal samples from Yangquan and Shouyang blocks in the Qinshui Basin were investigated. Field emission scanning electron microscopy (FESEM) and CO2 adsorption combined with nuclear magnetic resonance cryoporometry (NMRC) experiments were used to evaluate the pore structure with diameters ranging from 0 to 500 nm and their impact on adsorption capacity based on qualitative and quantitative analysis. The results show that a coalification jump from semianthracite to anthracite occurred in the study area due to the magmatic intrusion. In the process, the volume of supermicropores and micropores largely increased while the volume of transition pores and mesopores decreased slightly. Additionally, vitrinite gets purified and enriched during the rapid maturation of coal reservoir, which is beneficial to the microporous structure development. The pore size distribution (PSD) of anthracite is mainly divided into two types, which are in serrated and decreasing forms, respectively. Higher vitrinite content can promote the formation of decreasing type (type II), which corresponds to a lower degree of complexity. The fractal dimensions indicate that the heterogeneity of coal samples is increasing with the decrease in pore size. Accordingly, the increase in pore heterogeneity corresponds to the lower adsorption capacity. The main pore sizes that contribute to CBM adsorption include two parts: 25‐30 nm and 50‐60 nm. For the supermicropores with large specific surface areas, the pore system detected by CO2 molecules is not conducive to CBM adsorption, while the increase in pore volume can improve the adsorption rate and capacity of CO2. These findings are vital for a precisely understanding of nanoscale pores as well as future CBM exploitation.
Forecasting in long horizons using smoothed direct forecast
Authors: Baek Yaein 
Published: January 2019

AbstractThis paper constructs a forecast method that obtains long‐horizon forecasts with improved performance through modification of the direct forecast approach. Direct forecasts are more robust to model misspecification compared to iterated forecasts, which makes them preferable in long horizons. However, direct forecast estimates tend to have jagged shapes across horizons. Our forecast method aims to “smooth out” erratic estimates across horizons while maintaining the robust aspect of direct forecasts through ridge regression, which is a restricted regression on the first differences of regression coefficients. The forecasts are compared to the conventional iterated and direct forecasts in two empirical applications: real oil prices and US macroeconomic series. In both applications, our method shows improvement over direct forecasts.
Numerical simulation on the dynamics of continental lithosphere extension and break‐up
Authors: Shen Yibo , Zhang Guowei 
Published: January 2019

This study simulated continental lithosphere extension and break‐up through performing 2D numerical modelling with the “I2VIS” code. Based on the simulation results, the process of continental lithosphere extension and break‐up at different stages under different boundary conditions is quantitatively analysed, and its major controlling factors were determined. Through a comparative analysis of different simulation results, the following findings could be obtained: (a) During slow extension, increasing extension rate leads to increased thinning of the continental lithosphere, further increasing the corresponding thickness of sediments. Meanwhile, a centre of settlement appears on the terrestrial side of the initial basin, and sediment deposition occurred. This slow extension mode does not induce intense destruction of the lithosphere with low‐angle fault, which does not control deposition in the basin. Therefore, low extension rate is possibly a dominant factor controlling the formation of a depression‐type basin. (b) In the fast extension mode (at a rate of 10 mm/a), when hydrated mantle is absent, the continental crust experiences noticeable destruction. According to the simulation results, several translithospheric faults are observed in the absence of hydrated mantle. This indicates that continental lithosphere destruction is closely related to extension rate and lithospheric rheology.
The basement and volcanic activities of the Xisha Islands: Evidence from the kilometre‐scale drilling in the northwestern South China Sea
Authors: Zhang Yu , Yu Kefu , Qian Handong , Fan Tianlai , Yue Yuanfu , Wang Rui , Jiang Wei , Xu Shendong , Wang Yinghui 
Published: January 2019

As one of the microcontinents dispersed in the South China Sea (SCS), the Xisha microcontinent lacks the petrological evidence of the Cenozoic magmatic activity and basement. Well CK‐2, as a full‐coring kilometre‐scale major scientific drilling in Xisha Islands in the northwestern SCS, drilled through the thick reefal limestone and into the underlying basaltic pyroclastic rocks basement. This paper presents zircon U–Pb age and mineral chemistry of clinopyroxenes from the basaltic pyroclastic rocks. Mineral composition of the clinopyroxenes suggests that most of the clinopyroxenes are composed of diopside, which contains relatively high Al(w(Al2O3) = 5.03%–10.25%) and Ti(w(TiO2) = 2.2%–4.95%). The clinopyroxene discrimination diagrams show that the primary magma is alkaline basalt and likely generated in an intraplate tectonic setting. U–Pb dating of zircons by LA‐ICP‐MS yielded a wide range of ages: 36–33, 116–104, 148–140, 207–196, 255–236, 440, 808–749, and 2,440–1185 Ma. The youngest group has an average age of 35.5 ± 0.9 Ma, which is considered as the maximum age of the basalt eruption. The 2440 ± 19 Ma, which is the oldest zircons in the SCS, are firstly found in the basaltic pyroclastic rocks from the SCS, suggesting that the SCS may contain very old materials. The ages of the inherited zircons are comparable to magmatic activities that occurred around the SCS, implying that they were probably once linked and an integrated part of Gondwana. The ancient continental basement has experienced multistages magmatic events.