bluuebunny/crossref_metadata_2025_split huggingface dataset:
Minimal Surfaces in the Round Three‐Sphere by Doubling the Equatorial Two‐Sphere, II
Authors: Kapouleas Nikolaos , McGrath Peter 
Published: July 2019

AbstractIn a previous paper, new closed embedded smooth minimal surfaces in the round three‐sphere were constructed, each resembling two parallel copies of the equatorial two‐sphere joined by small catenoidal bridges, with the catenoidal bridges concentrating along two parallel circles, or the equatorial circle and the poles. In this sequel, we generalize those constructions so that the catenoidal bridges can concentrate along an arbitrary number of parallel circles, with the further option to include bridges at the poles. The current constructions follow the linearized doubling (LD) methodology developed in the previous paper. The LD solutions constructed here can be modified readily for use to doubling constructions of rotationally symmetric minimal surfaces with asymmetric sides [15]. In particular, they allow us to develop doubling constructions for the catenoid in Euclidean three‐space, the critical catenoid in the unit ball, and the spherical shrinker of the mean curvature flow.Unlike in the previous paper, our constructions here allow for sequences of minimal surfaces where the catenoidal bridges tend to be “densely distributed,” that is, they do not miss any open set of in the limit. This in particular leads to interesting observations that seem to suggest that it may be impossible to construct embedded minimal surfaces with isolated singularities by concentrating infinitely many catenoidal necks at a point. © 2019 Wiley Periodicals, Inc.
Quantization in Geometric Pluripotential Theory
Authors: Darvas Tamás , Lu Chinh H. , Rubinstein Yanir A. 
Published: July 2019

The space of Kähler metrics, on the one hand, can be approximated by subspaces of algebraic metrics, while, on the other hand, it can also be enlarged to finite‐energy spaces arising in pluripotential theory. The latter spaces are realized as metric completions of Finsler structures on the space of Kähler metrics. The former spaces are the finite‐dimensional spaces of Fubini‐Study metrics of Kähler quantization. The goal of this article is to draw a connection between the two.We show that the Finsler structures on the space of Kähler potentials can be quantized. More precisely, given a Kähler manifold polarized by an ample line bundle we endow the space of Hermitian metrics on powers of that line bundle with Finsler structures and show that the resulting path length metric spaces recover the corresponding metric completions of the Finsler structures on the space of Kähler potentials. This has a number of applications, among them a new Lidskii‐type inequality on the space of Kähler metrics, a new approach to the rooftop envelopes and Pythagorean formulas of Kähler geometry, and approximation of finite‐energy potentials, as well as geodesic segments by the corresponding smooth algebraic objects. © 2019 Wiley Periodicals, Inc.
Non‐Fluorinated Polymer Composite Proton Exchange Membranes for Fuel Cell Applications – A Review
Authors: Esmaeili Nazila , Gray Evan MacA. , Webb Colin J. 
Published: July 2019

AbstractThe critical component of a proton exchange membrane fuel cell (PEMFC) system is the proton exchange membrane (PEM). Perfluorosulfonic acid membranes such as Nafion are currently used for PEMFCs in industry, despite suffering from reduced proton conductivity due to dehydration at higher temperatures. However, operating at temperatures below 100 °C leads to cathode flooding, catalyst poisoning by CO, and complex system design with higher cost. Research has concentrated on the membrane material and on preparation methods to achieve high proton conductivity, thermal, mechanical and chemical stability, low fuel crossover and lower cost at high temperatures. Non‐fluorinated polymers are a promising alternative. However, improving the efficiency at higher temperatures has necessitated modifications and the inclusion of inorganic materials in a polymer matrix to form a composite membrane can be an approach to reach the target performance, while still reducing costs. This review focuses on recent research in composite PEMs based on non‐fluorinated polymers. Various inorganic fillers incorporated in the PEM structure are reviewed in terms of their properties and the effect on PEM fuel cell performance. The most reliable polymers and fillers with potential for high temperature proton exchange membranes (HTPEMs) are also discussed.
Electrochemical Thermoelectric Conversion with Polysulfide as Redox Species
Authors: Liang Yimin , Hui Joseph K.‐H. , Yamada Teppei , Kimizuka Nobuo 
Published: July 2019

AbstractThermocells convert waste heat to electricity without any pollution; however, the high cost and corrosivity of redox species hinder their commercialization. In this work, a thermocell that utilizes abundant polysulfide as redox species was demonstrated for the first time. 1‐Butyl‐1‐methylpyrrolidinium polysulfide [(P14)2S3] was synthesized, and the redox species were prepared by the addition of sulfur to the (P14)2S3 solution in DMSO. In thermoelectric measurements, the Seebeck coefficient changed from −0.68 to +0.5 mV K−1 through addition of sulfur to the cell. Operando UV/Vis spectroscopy and open‐circuit voltage analysis revealed that this effect was attributed to the change in the dominating redox reactions by the addition of sulfur. This result also provides a thermodynamic view on polysulfides electrochemistry, which is of high importance for lithium–sulfur batteries.
Structure‐Tunable Copper–Indium Catalysts for Highly Selective CO2 Electroreduction to CO or HCOOH
Authors: Zhu Minghui , Tian Pengfei , Li Jiayu , Chen Jiacheng , Xu Jing , Han Yi‐Fan 
Published: July 2019

AbstractSelectively approaching chemicals with one composition‐tunable catalyst is attractive for practical manufacturing. Bimetallic copper–indium (Cu–In) catalysts have been synthesized by using a coprecipitation method and found to be among the best reported In‐based catalysts for electrochemical CO2 reduction to CO or HCOOH. By varying the metal ratio, the catalyst can be tuned from a core–shell structure that selectively produces CO to a well‐mixed structure that prefers HCOOH production. The distinct selectivities depend on the structure‐sensitive binding strength of key reactive intermediates. These findings can benefit the development of a broader range of selectivity‐tunable catalysts.
Cross‐layer 1 and 5 user grouping/power allocation/subcarrier allocations for downlink OFDMA/NOMA video communications
Authors: Tseng Shu‐Ming , Tsai Wen‐Da , Suo Hao‐Sheng 
Published: July 2019

SummaryWang et al proposed cross‐layer resource allocation for orthogonal frequency division multiple access (OFDMA) video transmission systems. Unlike Wang et al, we add non‐orthogonal multiple access (NOMA) to the downlink OFDMA video transmission system and propose power allocation for users on each subcarrier (cluster) to minimize sum of video mean square error (MSE) to increase the peak signal‐to‐noise ratio (PSNR), the video quality. For OFDMA/NOMA video communication systems, we propose cross‐layer user clustering to reassign the subcarriers based on sum video distortion minimization and derive the optimal power allocation among NOMA users on the same subcarrier to minimize the sum video distortion. Numerical results show that the proposed scheme outperforms the previous OFDMA cross‐layer scheme by Wang et al by 2.2 to 4.5 dB in PSNR and previous OFDMA NOMA physical layer scheme by Ali et al by 2 to 4.4 dB in PSNR, when SNR = 15 dB, and the number of users is 6 to 12.
Banking the Future: Adolescent Capacity to Consent to Biobank Research
Authors: McGregor Kyle A. , Ott Mary A. 
Published: July 2019

ABSTRACTAdolescents are an important population to represent in biobanks. Inclusion of biospecimens from adolescents advances our understanding of the long‐term consequences of pediatric disease and allows the discovery of methods to prevent adult diseases during childhood. Consent for biobanking is complex, especially when considering adolescent participation, as it brings up issues that are not present with general clinical research. The development and successful implementation of an adolescent capacity assessment tool applied specifically to biobanking can potentially provide researchers and clinicians with contextualized information on participants’ understanding, appreciation, reasoning, and voluntary choice for biobanks. This tool would enhance current studies looking at the role of shared decision‐making in biobanking, as well as provide a formal measurement when considering decisions around pediatric and adolescent biobanking participation. This study adapted the MacCAT‐CR for use with a hypothetical adolescent biobank study and examines predictors of MacCAT‐CR scores on healthy and chronically ill adolescents.
Large‐scale forest restoration stabilizes carbon under climate change in Southwest United States
Authors: McCauley Lisa A. , Robles Marcos D. , Woolley Travis , Marshall Robert M. , Kretchun Alec , Gori David F. 
Published: July 2019

AbstractHigher tree density, more fuels, and a warmer, drier climate have caused an increase in the frequency, size, and severity of wildfires in western U.S. forests. There is an urgent need to restore forests across the western United States. To address this need, the U.S. Forest Service began the Four Forest Restoration Initiative (4FRI) to restore four national forests in Arizona. The objective of this study was to evaluate how restoration of ~400,000 ha under the 4FRIprogram and projected climate change would influence carbon dynamics and wildfire severity from 2010 to 2099. Specifically, we estimated forest carbon fluxes, carbon pools and wildfire severity under a moderate and fast 4FRIimplementation schedule and compared those to status quo and no‐harvest scenarios using theLANDIS‐IIsimulation model and climate change projections. We found that the fast‐4FRIscenario showed early decreases in ecosystem carbon due to initial thinning/prescribed fire treatments, but total ecosystem carbon increased by 9–18% over no harvest by the end of the simulation. This increased carbon storage by 6.3–12.7 million metric tons, depending on the climate model, equating to removal of carbon emissions from 55,000 to 110,000 passenger vehicles per year until the end of the century. Nearly half of the additional carbon was stored in more stable soil pools. However, climate models with the largest predicted temperature increases showed declines by late century in ecosystem carbon despite restoration. Our study uses data from a real‐world, large‐scale restoration project and indicates that restoration is likely to stabilize carbon and the benefits are greater when the pace of restoration is faster.
Yellow perch genetic structure and habitat use among connected habitats in eastern Lake Michigan
Authors: Chorak Gregory M. , Ruetz Carl R. , Thum Ryan A. , Partridge Charlyn G. , Janetski David J. , Höök Tomas O. , Clapp David F. 
Published: July 2019

AbstractMaintenance of genetic and phenotypic diversity is widely recognized as an important conservation priority, yet managers often lack basic information about spatial patterns of population structure and its relationship with habitat heterogeneity and species movement within it. To address this knowledge gap, we focused on the economically and ecologically prominent yellow perch (Perca flavescens). In the Lake Michigan basin, yellow perch reside in nearshore Lake Michigan, including drowned river mouths (DRMs)—protected, lake‐like habitats that link tributaries to Lake Michigan. The goal of this study was to examine the extent that population structure is associated with Great Lakes connected habitats (i.e., DRMs) in a mobile fish species using yellow perch as a model. Specifically, we tested whether DRMs and eastern Lake Michigan constitute distinct genetic stocks of yellow perch, and if so, whether those stocks migrate between the two connected habitats throughout the year. To do so, we genotyped yellow perch at 14 microsatellite loci collected from 10 DRMs in both deep and littoral habitats during spring, summer, and autumn and two nearshore sites in Lake Michigan (spring and autumn) during 2015–2016 and supplemented our sampling with fish collected in 2013. We found that yellow perch from littoral‐DRM habitats were genetically distinct from fish captured in nearshore Lake Michigan. Our data also suggested that Lake Michigan yellow perch likely use deep‐DRM habitats during autumn. Further, we found genetic structuring among DRMs. These patterns support hypotheses of fishery managers that yellow perch seasonally migrate to and from Lake Michigan, yet, interestingly, these fish do not appear to interbreed with littoral fish despite occupying the same DRM. We recommend that fisheries managers account for this complex population structure and movement when setting fishing regulations and assessing the effects of harvest in Lake Michigan.
Population genetic structure and connectivity of the seagrass Thalassia hemprichii in the Western Indian Ocean is influenced by predominant ocean currents
Authors: Jahnke Marlene , Gullström Martin , Larsson Josefine , Asplund Maria E. , Mgeleka Said , Silas Mathew Ogalo , Hoamby Arielle , Mahafina Jamal , Nordlund Lina Mtwana 
Published: July 2019

AbstractThis study is the first large‐scale genetic population study of a widespread climax species of seagrass, Thalassia hemprichii, in the Western Indian Ocean (WIO). The aim was to understand genetic population structure and connectivity of T. hemprichii in relation to hydrodynamic features. We genotyped 205 individual seagrass shoots from 11 sites across the WIO, spanning over a distance of ~2,700 km, with twelve microsatellite markers. Seagrass shoots were sampled in Kenya, Tanzania (mainland and Zanzibar), Mozambique, and Madagascar: 4–26°S and 33–48°E. We assessed clonality and visualized genetic diversity and genetic population differentiation. We used Bayesian clustering approaches (TESS) to trace spatial ancestry of populations and used directional migration rates (DivMigrate) to identify sources of gene flow. We identified four genetically differentiated groups: (a) samples from the Zanzibar channel; (b) Mozambique; (c) Madagascar; and (d) the east coast of Zanzibar and Kenya. Significant pairwise population genetic differentiation was found among many sites. Isolation by distance was detected for the estimated magnitude of divergence (DEST), but the three predominant ocean current systems (i.e., East African Coastal Current, North East Madagascar Current, and the South Equatorial Current) also determine genetic connectivity and genetic structure. Directional migration rates indicate that Madagascar acts as an important source population. Overall, clonality was moderate to high with large differences among sampling sites, indicating relatively low, but spatially variable sexual reproduction rates. The strongest genetic break was identified for three sites in the Zanzibar channel. Although isolation by distance is present, this study suggests that the three regionally predominant ocean current systems (i.e., East African Coastal Current, North East Madagascar Current, and the South Equatorial Current) rather than distance determine genetic connectivity and structure of T. hemprichii in the WIO. If the goal is to maintain genetic connectivity of T. hemprichii within the WIO, conservation planning and implementation of marine protection should be considered at the regional scale—across national borders.
Feather steroid hormone concentrations in relation to age, sex, and molting time in a long‐distance migratory passerine
Authors: Adámková Marie , Bílková Zuzana , Tomášek Oldřich , Šimek Zdeněk , Albrecht Tomáš 
Published: July 2019

AbstractIn birds, concentrations of testosterone (T) and corticosterone (Cort) are closely connected with many morphological, behavioral, and other physiological traits, including reproduction, metabolism, immunity, and fitness. The direction of the effect of these hormones on above‐mentioned traits, and the potential feedback between hormones are in general unclear; in addition, knowledge on how age and sex can affect T and Cort concentrations is still inconsistent. Our study used a novel method to analyze testosterone and corticosterone in feathers (Tf, Cortf) based on the precolumn chemical derivatization of hormones before liquid chromatography–tandem mass spectrometry (LC‐MS/MS) analysis. Unlike previously used methods (RIA, EIA), our analytical procedure allows simultaneous analysis of both hormones from small amounts of feathers (4–25 mg) and, thus, overcomes the problem of insufficient detection limits. We applied this method to reveal associations between Tf and Cortf hormone concentrations and feather growth, age, and sex in feathers grown during the postbreeding (flanks) and prebreeding (tails) periods in barn swallows (Hirundo rustica). There was neither a correlation between prebreeding and postbreeding Tf, nor between prebreeding and postbreeding Cortf. Tail Cortf concentrations were negatively associated with tail feather growth rates. Feather hormone concentrations were correlated in the prebreeding period, negatively in males but positively in females. Both Cortf and Tf were higher in young birds compared to older ones, indicating either an age‐related decrease in hormone concentrations within individuals, or the selective disappearance of individuals with high steroid concentrations. Males and females did not differ in Cortf, but Tf concentrations were higher in males than females, particularly during the prebreeding period. In this study, we provide an effective method for analyzing hormones in feathers in an ecological context, especially in situations when the total amount of feathers available for the analysis is limited.
Fences reduce habitat for a partially migratory ungulate in the Northern Sagebrush Steppe
Authors: Jones Paul F. , Jakes Andrew F. , Telander Andrew C. , Sawyer Hall , Martin Brian H. , Hebblewhite Mark 
Published: July 2019

AbstractFew studies have examined differential responses of partially migratory ungulates to human development or activity, where some individuals in a population migrate and others do not. Yet understanding how animals with different movement tactics respond to anthropogenic disturbance is key to sustaining global ungulate migrations. We examined seasonal resource selection of a partially migratory population of pronghorn (Antilocapra americana) in the Northern Sagebrush Steppe of Alberta, Saskatchewan, and Montana from 2003 to 2011. We developed step‐selection functions (SSF) for migrant and resident pronghorn during the summer and winter at two spatial scales (second order and third order) and then integrated SSFs across scales to estimate pronghorn responses to fences and subsequent habitat loss from these features while accounting for responses to other resource use. Both migrant and resident pronghorn showed the strongest responses to natural and anthropogenic features at the second order and weaker responses at the third order. Selection responses of migrant and residents differed the most in response to normalized difference vegetation index, topography, and anthropogenic features. Seasonally, selection for intermediate greenness was strongest in summer, whereas avoidance of roads strongly influenced winter resource selection of both tactics. Both migrant and resident pronghorn showed strong avoidance of fencing at both spatial scales during summer and winter. Model predictions with complete removal of fences from the landscape (i.e., natural conditions) predicted an increase in the area of high‐quality habitat of 16–38%. In contrast, doubling fence density on the landscape decreased the amount of high‐quality habitat by 1–11% and increased low‐quality habitat by 13–21%. Our results suggest that pronghorn winter and summer ranges can be improved by reducing the density of fences on the landscape, or mitigation measures to enhance fence crossings, to alleviate the indirect loss of habitat for this important endemic prairie species.
Adsorption of perchlorate from water using quaternary ammonium‐functionalized chitosan beads
Authors: Sowmya Appunni , Das Debanjani , Prabhakar Sivaraman , Kumar Marichamy Magesh , Anbalagan Kumaraguru , Rajesh Mathur 
Published: July 2019

AbstractPerchlorate, one of the persistent inorganic pollutants, was efficiently removed from water using quaternary ammonium‐functionalized cross‐linked chitosan beads (QACB). This synthesized bead was found to be efficient in terms of perchlorate removal capacity, 100% regeneration of used beads (using HCl or NaCl) and selectivity in the presence of coanions, namely, chloride, sulfate, carbonate, and nitrate. QACB removes perchlorate by exchange of chloride ions. QACB was able to remove >95% perchlorate from brackish water. Batch studies were carried out in order to optimize the condition for maximum perchlorate removal. The perchlorate removal capacity of QACB from 1,000 mg/L of aqueous solutions was 153.0 mg/g. The outcome of pH variation studies indicated that QACB is able to remove perchlorate in the pH ranges of 2–11. Equilibrium isotherm data of adsorption of perchlorate at temperature 303, 313, and 323 K were well fitted to the linear Freundlich, Langmuir, and Dubinin–Radushkevich isotherm models. The adsorption kinetics data were best described by the pseudo‐second‐order kinetic model. FTIR was used to confirm the interaction of perchlorate with QACB. A small‐scale column test was carried out to evaluate the capacity of QACB for removing perchlorate from brackish water.
A limiter‐based well‐balanced discontinuous Galerkin method for shallow‐water flows with wetting and drying: Triangular grids
Authors: Vater Stefan , Beisiegel Nicole , Behrens Jörn 
Published: July 2019

SummaryA novel wetting and drying treatment for second‐order Runge‐Kutta discontinuous Galerkin methods solving the nonlinear shallow‐water equations is proposed. It is developed for general conforming two‐dimensional triangular meshes and utilizes a slope limiting strategy to accurately model inundation. The method features a nondestructive limiter, which concurrently meets the requirements for linear stability and wetting and drying. It further combines existing approaches for positivity preservation and well balancing with an innovative velocity‐based limiting of the momentum. This limiting controls spurious velocities in the vicinity of the wet/dry interface. It leads to a computationally stable and robust scheme, even on unstructured grids, and allows for large time steps in combination with explicit time integrators. The scheme comprises only one free parameter, to which it is not sensitive in terms of stability. A number of numerical test cases, ranging from analytical tests to near‐realistic laboratory benchmarks, demonstrate the performance of the method for inundation applications. In particular, superlinear convergence, mass conservation, well balancedness, and stability are verified.
High‐Frequency Price Discovery and Price Efficiency on Interest Rate Futures
Authors: Nie Jing 
Published: July 2019

AbstractThis paper estimates a collection of high‐frequency informational efficiency metrics by constructing a unique Eurodollar futures data set with the complete messaging history. To capture price efficiency, this paper calculates the mid‐quote return autocorrelations following a full range of time intervals. The findings suggest the mid‐quote return autocorrelations are positive and gradually increase from the tick‐level to 30‐min. Then, I utilize a vector autoregression to estimate the pricing error, which shows the adjustment time of trade returns is completed in 1 s. Furthermore, trade prices are less sensitive about incorporating any available new information as the Eurodollar futures approaches its maturity.