bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing dual hair sampling for isotopic studies of grizzly bears
Authors: Ueda Momoko , Bell Lynne S. 
Published: May 2019

RationaleThe stable isotope ratios of carbon (δ13C values), nitrogen (δ15N values) and sulfur (δ34S values) in bear hair can be used to obtain information on dietary history. Sample protocols often require hair sampling from multiple anatomical locations; however, there remains a question as to whether this is necessary for isotopic studies of hair. The purpose of this study was to determine whether significant differences can be observed for the δ13C, δ15N and δ34S values between paired hair samples taken from the rump and shoulder of grizzly bears (Ursus arctos).MethodsPaired hair samples were collected from the rump and the shoulder of 81 grizzly bears in the Yukon, Canada. Hair samples were analyzed using a thermal combustion elemental analyzer coupled with a continuous flow isotope ratio mass spectrometer.ResultsStatistical comparisons of paired hair samples for both males and females showed no meaningful differences in δ13C, δ15N and δ34S values in hair taken from the rump and shoulder, and any observed differences fell within the instrumental error.ConclusionsBased on these results, hair may be safely sampled on either the rump or the shoulder without loss of isotopic information and thus this finding allows for refinement of sampling.
Grazing high and low: Can we detect horse altitudinal mobility using high‐resolution isotope (δ13C and δ15N values) time series in tail hair? A case study in the Mongolian Altai
Authors: Lazzerini Nicolas , Coulon Aurélie , Simon Laurent , Marchina Charlotte , Noost Bayarkhuu , Lepetz Sébastien , Zazzo Antoine 
Published: May 2019

RationaleCarbon and nitrogen stable isotope time series performed in continuously growing tissues (hair, tooth enamel) are commonly used to reconstruct the dietary history of modern and ancient animals. Predicting the effects of altitudinal mobility on animal δ13C and δ15N values remains difficult as several variables such as temperature, water availability or soil type can contribute to the isotope composition. Modern references adapted to the region of interest are therefore essential.MethodsBetween June 2015 and July 2018, six free‐ranging domestic horses living in the Mongolian Altaï were fitted with GPS collars. Tail hairs were sampled each year, prepared for sequential C and N isotope analysis using EA‐IRMS. Isotopic variations were compared with altitudinal mobility, and Generalized Additive Mixed (GAMMs) models were used to model the effect of geographic and environmental factors on δ13C and δ15N values.ResultsLess than half of the pasture changes were linked with a significant isotopic shift while numerous isotopic shifts did not correspond to any altitudinal mobility. Similar patterns of δ13C and δ15N variations were observed between the different horses, despite differences in mobility patterns. We propose that water availability as well as seasonal availability of N2 fixing type plants primarily controlled horse hair δ13C and δ15N values, overprinting the influence of altitude.ConclusionsOur study shows that altitudinal mobility is not the main factor that drives the variations in horse tail hair δ13C and δ15N values and that seasonal change in the animal dietary preference also plays an important role. It is therefore risky to interpret variations in δ13C and δ15N values of animal tissues in terms of altitudinal mobility alone, at least in C3–dominated environments.
Small hydropower dam alters the taxonomic composition of benthic macroinvertebrate assemblages in a neotropical river
Authors: Linares Marden Seabra , Assis Waldecy , de Castro Solar Ricardo Ribeiro , Leitão Rafael Pereira , Hughes Robert M. , Callisto Marcos 
Published: May 2019

AbstractHydropower dams substantially modify lotic ecosystems. Most studies regarding their ecological impacts are based on large dams and provide little information about the far more abundant effects of small hydropower dams. Our aim was to characterize the ecological effects of a small hydropower dam and run‐of‐the‐river reservoir on the structure of benthic macroinvertebrate assemblages in the Pandeiros River located in the neotropical savanna of Brazil. We tested the hypothesis that benthic macroinvertebrate assemblages in sites directly affected by the dam and reservoir would show a different taxonomic structure compared with those in free‐flowing sites. We expected to find sensitive native species associated with the free‐flowing sites, whereas resistant and non‐native invasive taxa were expected in impounded sites. We also explored associations between the presence of native and non‐native invasive taxa to each habitat type. We found that the structure of benthic macroinvertebrate assemblages was significantly different between free‐flowing and impounded sites. Also, we found that the dam and reservoir facilitated colonization of non‐native invasive species (Corbicula fluminea and Melanoides tuberculata) because only in those sites they were found in high abundance, in contrast to the free‐flowing sites. Although the environmental conditions imposed by the impoundment altered the structure of benthic macroinvertebrate assemblages, the effects were limited to sites closest to the dam. Our results highlight the necessity of understanding physical habitat changes caused by the presence and management of run‐of‐the‐river dams and reservoirs.
Bridge pier scour under pressure flow conditions
Authors: Carnacina Iacopo , Pagliara Stefano , Leonardi Nicoletta 
Published: May 2019

AbstractThe probability of pressurized flow conditions occurring in existing bridges is forecast to increase due to possible changes in extreme precipitation, storm surges, and flooding predicted under climate change scenarios. The presence of a pressure flow is generally associated with scouring processes in proximity to the bridge. Scouring can also occur around bridge piers, possibly causing infrastructure failure. Although there is a vast literature on bridge pier scour and pressure flow scour, only a few studies have investigated their combined effect. This study will provide a new overview of the main features of bridge pier scour under pressurized flow conditions, based on laboratory experiences. Special focus is placed on the analysis of the flow features under pressure and free surface conditions and to the temporal evolution of the scour. A comparison with existing literature data is also conducted. The results highlight the nonlinear nature of scour processes and the need to consider pressurized flow conditions during structural design, as the interaction between pressure flow and the bridge pier strongly influences scour features and leads to scour depths much greater than the sum of the individual scours created only by pressure flow or pier presence.
Process Development and DFT‐Assisted Mechanism of the Vapour Phase Ammoxidation of 2,6‐Dichlorotoluene to 2,6‐Dichlorobenzonitrile over the V2O5/γ‐Al2O3 Catalyst
Authors: Dwivedi Ritambhara , Kumar Ashok , Khare Savita , Prasad Rajendra 
Published: May 2019

AbstractAmmoxidation of 2,6‐dichlorotoluene (2,6‐DCLT) to 2,6‐dichlorobenzonitrile (2,6‐DCLBN) over V2O5/γ‐Al2O3 catalyst has been carried out in a fixed bed reactor. A maximum conversion of 96% of (2,6‐DCLT) and 79% yield to 2,6‐dichlorobenzonitrile have been obtained at a temperature of 425 °C, Air : 2,6‐DCLT mole ratio of 22 : 1 and NH3 : 2,6‐DCLT mole ratio of 11 : 1. A DFT theory computations have been performed with the objective of finding a mechanism of the reaction, activation energy and transition state for different reactions. Abstraction of C−H bond with an activation energy of 64.60 kcal mol−1 was found to be rate determining step. A new approach has been suggested for the reoxidation of the catalyst which supports reoxidation of every step associated with dehydration of species during the reaction. This finding is a contrary of the previous studies which assume reoxidation of the catalyst at the end of all reactions. Rapid reoxidation of the catalyst surface to release water is found to be the driving force for all reactions involving the cleavage of C−H or N−H bonds.
A Self‐Assembled Flower‐Like Structure of Nickel‐Cobalt Phosphide Nanosheets Supported on Nickel Foam for Electrochemical Hydrogen Evolution Reaction
Authors: Li Shengjuan , Zou Yicheng , Li Lei , Dong Yongguang , Zhu Yufang 
Published: May 2019

AbstractIn this study, flower‐like nickel‐cobalt phosphide (NiCoP) on Ni foam (flower‐like NiCoP/NF) was fabricated via a two‐step process, including hydrothermal and phosphorization. Hydrogen evolution reaction (HER) measurements show that such flower‐like NiCoP/NF is a highly efficient and stable electrocatalyst, which can keep high activity for more than 20 h at ambient temperature. Scanning electron microscope (SEM) images show that flower‐like NiCoP/NF uniformly covered the Ni foam surface. In the hydrothermal step, X‐ray photoelectron spectroscopy (XPS) results show that partial Co2+ ions from Co(NO3)2⋅6H2O were oxidized to Co3+ ions in the ethanol‐water solution. Meanwhile, NO3− ions from Ni(NO3)2⋅6H2O and Co(NO3)2⋅6H2O triggered the ethanol‐water solution to release OH− ions, which subsequently reacted with Ni2+, Co2+ and Co3+ ions to generate NiCo‐OH precipitation. Subsequently, in the phosphorization step NiCo‐OH was converted to NiCoP nanosheets by NaH2PO2 at a low temperature of 350 °C. The two‐step method employed in the present work avoids an addition of alkali sources or precipitators to the hydrothermal reaction solution, which is favorable for environmental protection strategies and sustainable development principles.
Synthesis and Characterization of New Inorganic‐Organic Hybrid Nanocomposite PMo11Cu@MgCu2O4@CS as an Efficient Heterogeneous Nanocatalyst for ODS of Real Fuel
Authors: Rezvani Mohammad Ali , Shaterian Maryam , Aghbolagh Zahra Shokri , Akbarzadeh Fereshteh 
Published: May 2019

AbstractIn this work, a new nanocomposite (PMo11Cu@MgCu2O4@CS) was synthesized by reaction of copperII‐monosubstituted phosphomolybdate (PMo11Cu), magnesiocopperite (MgCu2O4) and Chitosan (CS) via the sol‐gel method. The assembled nanocomposite was characterized by FTIR, XRD, SEM. The catalytic activity of the nanocomposite was tested on oxidative desulfurization (ODS) of real gasoline in the presence of CH3COOH/H2O2 in the volume ratio of 1/2 as an oxidant. Additionally, the results were compared with the oxidation reaction of prepared model sulfur compounds at the same conditions. The ODS results showed that immobilized of PMo11Cu on the CS and MgCu2O4 nanoceramic increased the efficiency and activity of the PMo11Cu in the removal of organic sulfur compounds (OSCs). The PMo11Cu@CS @MgCu2O4 could be reused for at least five times without notable reduction in efficiency of ODS system. This investigation presents a promising approach to the efficient removal of OSCs from gasoline using PMo11Cu@MgCu2O4@CS catalyst under mild reaction conditions.
[PVP‐SO3H] HSO4: An Efficient Polymeric Solid Acid Catalyst for the Formylation and N‐Boc Protection Reactions
Authors: Pakpour‐Roudsari Fatemeh , Seddighi Mohadeseh , Shirini Farhad , Tajik Hassan 
Published: May 2019

AbstractIn the present work, the formylation of a variety of amines and alcohols was performed using [PVP‐SO3H] HSO4 as a powerful solid acid catalyst under solvent‐free conditions. Under this catalytic condition, N‐Boc protection of amines was also successfully done at room temperature. Easy and economical methodology, short reaction times, high yields, chemo‐selectivity, high TOF and easy workup are some of the advantages of this work. Furthermore, [PVP‐SO3H]HSO4 can be easily separated and reused for several times without considerable loss of its catalytic activity.
Rational Design of Semi‐Synthetic Protein Complexes with the Defined Oligomeric State
Authors: Sandanaraj Britto S , Reddy Mullapudi Mohan , Rao Kasuladevu Jagannadha , Bhandari Pavankumar Janardhan 
Published: May 2019

AbstractProtein oligomers are ubiquitous in nature and play an essential role in various biological processes. Recently, there is an enormous interest to custom‐make synthetic protein oligomers through the bottom‐up approach. In this regard, genetic methods have made tremendous progress in the last decade. In comparison, only few chemical methods currently exist for this purpose. Herein, we report a modular synthetic strategy for the design of facially amphiphilic globular protein‐synthetic peptide conjugates. The self‐assembly of these bioconjugates is driven by strong hydrophobic interaction of the peptide domain. The size, molecular mass and oligomeric state of semi‐synthetic protein complexes strongly depend on size and surface charge of a globular protein as well as the length of the hydrophobic peptide domain. A systematic structure‐property relationship study of these semi‐synthetic proteins should shed more light on the understanding of various non‐covalent forces, which governs the oligomerization processes of naturally occurring proteins.
Designing Highly Efficient and Long‐Term Durable Electrocatalyst for Oxygen Evolution by Coupling B and P into Amorphous Porous NiFe‐Based Material
Authors: Hu Fei , Wang Haiyun , Zhang Yan , Shen Xiaochen , Zhang Guanghui , Pan Yanbo , Miller Jeffrey T. , Wang Kun , Zhu Shengli , Yang Xianjin , Wang Chengming , Wu Xiaojun , Xiong Yujie , Peng Zhenmeng 
Published: May 2019

AbstractOxygen evolution reaction (OER) is of great significance for hydrogen production via water electrolysis, which, however, demands development of highly active, durable, and cost‐effective electrocatalysts in order to stride into a renewable energy era. Herein, highly efficient and long‐term durable OER by coupling B and P into an amorphous porous NiFe‐based electrocatalyst is reported, which possesses an amorphous porous metallic bulk structure and high corrosion resistance, and overcomes the issues associated with currently used catalyst nanomaterials. The PB codoping in the activated NiFePB (a‐NiFePB) delocalizes both Fe and Ni at Fermi energy level and enhances p–d hybridization as simulated by density functional theory calculations. The harmonized electronic structure and unique porous framework of the a‐NiFePB consequently improve the OER activity. The activated NiFePB thus exhibits an extraordinarily low overpotential of 197 mV for harvesting 10 mA cm−2 OER current density and 233 mV for reaching 100 mA cm−2 under chronopotentiometry condition, with the Tafel slope harmoniously conforming to 34 mV dec−1. Impressive long‐term stability of this new catalyst is evidenced by only limited activity decay after 1400 h operation at 100 mA cm−2. This work strategically directs a way for heading up a promising energy conversion alternative.
PAxSPL: A feature retrieval process for software product line reengineering
Authors: Marchezan Luciano , Macedo Rodrigues Elder , Bernardino Maicon , Paulo Basso Fábio 
Published: May 2019

SummarySoftware product lines (SPLs) are a well‐known solution to systematically create reusable software products. Among the approaches to create an SPL, the extractive approach is usually used when the organization already has a set of similar systems. These systems are analyzed to extract, categorize, and group their common and variant features throughout the SPL reengineering process. As there are different scenario variables, such as available artifacts and team experience, the activities and techniques used to perform these tasks may change. This may increase the effort and decrease the quality of retrieved features when users with low experience in SPL reengineering perform such tasks. However, there is a lack of a process supporting these tasks considering different scenarios. Therefore, we specify the Prepare, Assemble, and Execute Process for SPL Reengineering (PAxSPL), a process that provides support to prepare, assemble, and execute feature retrieval throughout the analysis of documentation and team experience. To initially evaluate PAxSPL, we conducted and reported an exploratory case study in a real development environment. The results indicated that our proposal helps in the assembly of a feature retrieval process according to user needs. Results were important to identify points for improvement in PAxSPL. We also could use the information gathered to improve the guidelines and provide this information to be used as basis of comparison for future users.
Measuring the impact of additional instrumentation on the skill of numerical weather prediction models at forecasting wind ramp events during the first Wind Forecast Improvement Project (WFIP)
Authors: Akish Elena , Bianco Laura , Djalalova Irina V. , Wilczak James M. , Olson Joseph B. , Freedman Jeff , Finley Catherine , Cline Joel 
Published: May 2019

AbstractThe first Wind Forecast Improvement Project (WFIP) was a DOE and NOAA‐funded 2‐year‐long observational, data assimilation, and modeling study with a 1‐year‐long field campaign aimed at demonstrating improvements in the accuracy of wind forecasts generated by the assimilation of additional observations for wind energy applications. In this paper, we present the results of applying a Ramp Tool and Metric (RT&M), developed during WFIP, to measure the skill of the 13‐km grid spacing National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) Rapid Refresh (RAP) model at forecasting wind ramp events. To measure the impact on model skill generated by the additional observations, controlled data‐denial RAP simulations were run for six separate 7 to 12‐day periods (for a total of 55 days) over different seasons.The RT&M identifies ramp events in the time series of observed and forecast power, matches in time each forecast ramp event with the most appropriate observed ramp event, and computes the skill score of the forecast model penalizing both timing and amplitude errors. Because no unique definition of a ramp event exists (in terms of a single threshold of change in power over a single time duration), the RT&M computes integrated skill over a range of power change (Δp) and time period (Δt) values.A statistically significant improvement of the ramp event forecast skill is found through the assimilation of the special WFIP data in two different study areas, and variations in model skill between up‐ramp versus down‐ramp events are found.
Parameter identification in elasto‐plasticity: distance between parameters and impact of measurement errors
Authors: Shutov Alexey V. , Kaygorodtseva Anastasia A. 
Published: May 2019

AbstractA special aspect of parameter identification in finite‐strain elasto‐plasticity is considered. Namely, we analyze the impact of the measurement errors on the resulting set of material parameters. In order to define the sensitivity of parameters with respect to the measurement errors, a mechanics‐based distance between two sets of parameters is introduced. Using this distance function, we assess the reliability of certain parameter identification procedures. The assessment involves introduction of artificial noise to the experimental data; the noise can be both correlated and uncorrelated. An analytical procedure to speed up Monte Carlo simulations is presented. As a result, a simple tool for estimating the robustness of parameter identification is obtained. The efficiency of the approach is illustrated using a model of finite‐strain viscoplasticity, which accounts for combined isotropic and kinematic hardening. It is shown that dealing with correlated measurement errors, most stable identification results are obtained for non‐diagonal weighting matrix. At the same time, there is a conflict between the stability and accuracy.
Erfolgreicher Wissenserwerb im ersten Semester Physik
Authors: Woitkowski David 
Published: May 2019

ZusammenfassungDer Erwerb von Fachwissen auf einem Niveau, welches auf die typischen komplexen und abstrakten Problemstellungen der Universitätsphysik angewandt werden kann, stellt eine zentrale Herausforderung in der Studieneingangsphase dar. Verschiedene Probleme dieser Phase, wie die hohen Abbruch-/Schwundquoten, können auf fachliche Schwierigkeiten in diesem Kontext zurückgeführt werden. Auch im späteren Studium wird immer wieder konzeptionell auf dem hier gelernten Fachwissen aufgebaut, so dass diese Phase als kritisch angesehen werden kann.Die vorliegende Studie erhebt längsschnittlich das physikalische Fachwissen (Mechanik) bei 122 Physikstudierenden zu Beginn und Ende des ersten Studiensemesters. Die Studierenden können einem Niveaumodell zugeordnet werden, welches beschreibt, mit Aufgaben welcher Komplexität sie jeweils erfolgreich umgehen können.Diese Niveaus stellen einerseits ein Bewertungskriterium für die Qualität des vorhandenen Fachwissens dar und können so ein an Anforderungsmerkmalen orientiertes Zielkriterium für erfolgreichen Fachwissenserwerb liefern. Andererseits können die Niveaus eine erste Einschätzung davon liefern, welche Ausprägung des Vorwissen prädiktiv für erfolgreichen Wissenserwerb ist.Die Daten sprechen für einen wesentlichen Einfluss physikalischen und mathematischen Vorwissens auf die mittlere weitere Wissensentwicklung, insbesondere zeigen sich Hinweise auf eine additive Prädiktionskraft des schulischen Vorwissens für den Erwerb universitären Wissens bis Ende des ersten Semesters. Die Ergebnisse legen nahe, dass vor allem die Fähigkeit zum Umgang mit komplexen Problemstellungen prädiktiv für das universitäre Physiklernen ist – auch und gerade, wenn es im Rahmen der schulischen Physik erlernt wurde.
New taxa and revised stratigraphic distribution of the crinoid fauna from Anticosti Island, Québec, Canada (Late Ordovician-early Silurian)
Authors: Ausich William I. , Cournoyer Mario E. 
Published: May 2019

AbstractEnd-Ordovician extinctions had a profound effect on shallow-water benthic communities, including the Crinoidea. Further, recovery after the extinctions resulted in a macroevolutionary turnover in crinoid faunas. Anticosti Island is the most complete Ordovician-Silurian boundary section recording shallow-water habitats. Both new taxa and changes in Anticosti Island stratigraphic nomenclature are addressed herein. New taxa includeBecsciecrinus groulxin. sp.,Bucucrinus isotaloin. sp.,Jovacrinus clarkin. sp.,Plicodendrocrinus petrykin. sp.,Plicodendrocrinus martinin. sp.,Thalamocrinus daoustaen. sp., andLateranicrinus saintlaurentin. gen. n. sp. The status ofXenocrinus rubusas a boundary-crossing taxon is confirmed, range extensions of several taxa are documented, and the distribution of crinoids with the revised stratigraphic nomenclature is documented.UUID:http://zoobank.org/19613a44-ec69-47d7-88ab-fcf88ba771f0.
The Effects of Yaw on Conical Wings at High Supersonic Speeds
Authors: Hillier R. 
Published: May 2019

SummaryIn recent papers Squire has presented results for the shock shape and pressure distribution on the lower surface of unyawed, lifing, conical bodies with sharp leading edges. The work, a development of Messiter’s first-order correction to Newtonian theory, was successfully applied to wings of diamond and caret section. This paper shows how the method may be used to include the effects of yaw. Results are presented here for the flat wing and some biconvex sections. Comparisons are made with experiment for both the flat and biconvex wings and agreement is shown to be good.
The Dynamical Behaviour of a Flexible Cable in a Uniform Flow Field
Authors: Huffman R. R. , Genin Joseph 
Published: May 2019

SummaryA non-linear mathematical model for the study of the dynamics of an extensible cable subjected to aerodynamic forces generated by a uniform flow field is formulated. Solutions are found considering large displacement caused by suddenly applied loads (i.e., gusts, shock waves, turbulence) for a range of flow speeds and cable lengths. Transition from overdamped to oscillatory motion is observed when flow speed and cable length are increased and decreased respectively. The stability of the system is discussed.