bluuebunny/crossref_metadata_2025_split huggingface dataset:
The livelihood challenges of resettled communities of the Bui dam project in Ghana and the role of Chinese dam‐builders
Authors: Yankson Paul W. K. , Asiedu Alex B. , Owusu Kwadwo , Urban Frauke , Siciliano Giuseppina 
Published: April 2017

AbstractEmerging issues from the Bui hydropower project suggest that the experiences of two earlier hydropower projects in Ghana failed to prevent challenges related to resource access and livelihoods. This article examines the nature of the challenges, their causes, why they were not avoided and the role of the Chinese builders. We conducted 43 interviews and 11 focus group discussions and analyzed qualitative data by themes using narrative analysis. Our findings show that the livelihoods of the resettled communities are, on balance, negatively impacted by the construction of the dam. While Chinese dam‐builders played a major role in financing and enabling the dam's construction, the Ghanaian governance arrangements were found to be more important in addressing the livelihood challenges.
Probabilistic vs. deterministic fiber tracking and the influence of different seed regions to delineate cerebellar‐thalamic fibers in deep brain stimulation
Authors: Schlaier Juergen R. , Beer Anton L. , Faltermeier Rupert , Fellner Claudia , Steib Kathrin , Lange Max , Greenlee Mark W. , Brawanski Alexander T. , Anthofer Judith M. 
Published: April 2017

AbstractThis study compared tractography approaches for identifying cerebellar‐thalamic fiber bundles relevant to planning target sites for deep brain stimulation (DBS). In particular, probabilistic and deterministic tracking of the dentate‐rubro‐thalamic tract (DRTT) and differences between the spatial courses of the DRTT and the cerebello‐thalamo‐cortical (CTC) tract were compared. Six patients with movement disorders were examined by magnetic resonance imaging (MRI), including two sets of diffusion‐weighted images (12 and 64 directions). Probabilistic and deterministic tractography was applied on each diffusion‐weighted dataset to delineate the DRTT. Results were compared with regard to their sensitivity in revealing the DRTT and additional fiber tracts and processing time. Two sets of regions‐of‐interests (ROIs) guided deterministic tractography of the DRTT or the CTC, respectively. Tract distances to an atlas‐based reference target were compared. Probabilistic fiber tracking with 64 orientations detected the DRTT in all twelve hemispheres. Deterministic tracking detected the DRTT in nine (12 directions) and in only two (64 directions) hemispheres. Probabilistic tracking was more sensitive in detecting additional fibers (e.g. ansa lenticularis and medial forebrain bundle) than deterministic tracking. Probabilistic tracking lasted substantially longer than deterministic. Deterministic tracking was more sensitive in detecting the CTC than the DRTT. CTC tracts were located adjacent but consistently more posterior to DRTT tracts. These results suggest that probabilistic tracking is more sensitive and robust in detecting the DRTT but harder to implement than deterministic approaches. Although sensitivity of deterministic tracking is higher for the CTC than the DRTT, targets for DBS based on these tracts likely differ.
Estimates of heritability of atrial fibrillation in the Standardbred racehorse
Authors: Kraus M. , Physick‐Sheard P. W. , Brito L. F. , Schenkel F. S. 
Published: April 2017

SummaryBackgroundThe number of Standardbred racehorses admitted to the Ontario Veterinary College Teaching Hospital (Guelph, Canada) for treatment of atrial fibrillation (AF) has been on the rise since the early 1990s. A small number of sires have been contributing to a large proportion of cases, indicating there may be a genetic predisposition to the arrhythmia in this breed.ObjectivesThe objectives of this study were to determine the heritability of AF in Standardbred horses and whether heritability of the arrhythmia differs across gaits and/or sexes.Study designHeritability study based on retrospective review of clinical records and publicly available pedigree and racing records.MethodsStandardbred horses admitted to hospital for treatment of AF that were born between 1978 and 2007 comprised the affected case population (n = 204). Five randomly selected racing contemporaries for each case, assumed to not suffer from the arrhythmia, comprised the control population (n = 1017). Racing contemporaries were identified by examining the race records of affected horses within the 6 months prior to their admission, and randomly selecting sex‐ and gait‐matched horses from these races. Heritability was estimated from the sampled horses as a whole (n = 1221), as well as for both sexes and gaits, using a generalised linear mixed model.ResultsHeritability of AF on the underlying liability scale was estimated to be (±s.e.) 0.30±0.04 in the entire data set; 0.30±0.06 in males; 0.24±0.08 in females; and 0.32±0.05 in pacers. After conversion to the observed scale, heritability estimates were 0.14, 0.15, 0.09 and 0.15, respectively.Main limitationsThere were insufficient data to estimate heritability of AF for trotters.ConclusionsModest heritability estimates were found for AF in the Standardbred horse, particularly in males and pacers, which support the hypothesis that there is a genetic contribution to the arrhythmia in this breed.
The Summary is available in Chinese – See Supporting Information.
Structural features of Aspergillus niger β‐galactosidase define its activity against glycoside linkages
Authors: Rico‐Díaz Agustín , Ramírez‐Escudero Mercedes , Vizoso‐Vázquez Ángel , Cerdán M. Esperanza , Becerra Manuel , Sanz‐Aparicio Julia 
Published: April 2017

β‐Galactosidases are biotechnologically interesting enzymes that catalyze the hydrolysis or transgalactosylation of β‐galactosides. Among them, the Aspergillus niger β‐galactosidase (AnβGal) belongs to the glycoside hydrolase family 35 (GH35) and is widely used in the industry due to its high hydrolytic activity which is used to degrade lactose. We present here its three‐dimensional structure in complex with different oligosaccharides, to illustrate the structural determinants of the broad specificity of the enzyme against different glycoside linkages. Remarkably, the residues Phe264, Tyr304, and Trp806 make a dynamic hydrophobic platform that accommodates the sugar at subsite +1 suggesting a main role on the recognition of structurally different substrates. Moreover, complexes with the trisaccharides show two potential subsites +2 depending on the substrate type. This feature and the peculiar shape of its wide cavity suggest that AnβGal might accommodate branched substrates from the complex net of polysaccharides composing the plant material in its natural environment. Relevant residues were selected and mutagenesis analyses were performed to evaluate their role in the catalytic performance and the hydrolase/transferase ratio of AnβGal. Thus, we generated mutants with improved transgalactosylation activity. In particular, the variant Y304F/Y355H/N357G/W806F displays a higher level of galacto‐oligosaccharides production than the Aspergillus oryzae β‐galactosidase, which is the preferred enzyme in the industry owing to its high transferase activity. Our results provide new knowledge on the determinants modulating specificity and the catalytic performance of fungal GH35 β‐galactosidases. In turn, this fundamental background gives novel tools for the future improvement of these enzymes, which represent an interesting target for rational design.DatabaseStructural data are available in PDB database under the accession numbers 5IFP (native form), 5IHR (in complex with 6GalGlu), 5IFT (in complex with 3GalGlu), 5JUV (in complex with 6GalGal), 5MGC (in complex with 4GalLac), and 5MGD (in complex with 6GalLac).
Point stresses during reproductive stage rather than warming seasonal temperature determine yield in temperate rice
Authors: Espe Matthew B. , Hill Jim E. , Hijmans Robert J. , McKenzie Kent , Mutters Randall , Espino Luis A. , Leinfelder‐Miles Michelle , van Kessel Chris , Linquist Bruce A. 
Published: April 2017

AbstractClimate change is predicted to shift temperature regimes in most agricultural areas with temperature changes expected to impact yields of most crops, including rice. These temperature‐driven effects can be classified into point stresses, where a temperature event during a sensitive stage drives a reduction in yield, or seasonal warming losses, where raised temperature is thought to increase maintenance energy demands and thereby decrease available resources for yield formation. Simultaneous estimation of the magnitude of each temperature effect on yield has not been well documented due to the inherent difficulty in separating their effects. We simultaneously quantified the magnitude of each effect for a temperate rice production system using a large data set covering multiple locations with data collected from 1995 to 2015, combined with a unique probability‐based modeling approach. Point stresses, primarily cold stress during the reproductive stages (booting and flowering), were found to have the largest impact on yield (over 3 Mg/ha estimated yield losses). Contrary to previous reports, yield losses caused by increased temperatures, both seasonal and during grain‐filling, were found to be small (approximately 1–2% loss per °C). Occurrences of cool temperature events during reproductive stages were found to be persistent over the study period, and within season, the likelihood of a cool temperature event increased when flowering occurred later in the season. Short and medium grain types, typically recommended for cool regions, were found to be more tolerant of cool temperatures but more sensitive to heat compared to long grain cultivars. These results suggest that for temperate rice systems, the occurrence of periodic stress events may currently overshadow the impacts of general warming temperature on crop production.
Enhanced evapotranspiration was observed during extreme drought from Miscanthus, opposite of other crops
Authors: Joo Eva , Zeri Marcelo , Hussain Mir Zaman , DeLucia Evan H. , Bernacchi Carl J. 
Published: April 2017

AbstractThe impact of extreme drought and heat stress that occurred in the Midwestern U.S. in 2012 on evapotranspiration (ET), net ecosystem productivity (NEP), and water‐use efficiency (WUE) of three perennial ecosystems (switchgrass, miscanthus, prairie) and a maize/soybean agroecosystem was studied as part of a long‐term experiment. Miscanthus had a slower initial response but an eventually drastic ET as drought intensified, which resulted in the largest water deficit among the crops. The substantially higher ET at peak drought was likely supplied by access to deep soil water, but suggests that stomatal conductance of miscanthus during the drought may respond differently than the other ecosystems, consistent with an anisohydric strategy. While there was a discrepancy in the water consumption of maize and switchgrass/prairie in the early time of drought, all these ecosystems followed a water‐saving strategy when drought intensified. The gross primary production (GPP) of miscanthus dropped, but was reversible, when temperature reached 40 °C and still provided the largest total GPP among the ecosystems. Increased ET for miscanthus during 2012 resulted a large decline in ecosystem WUE compared to what was observed in other years. The biophysical responses of miscanthus measured during an extreme, historic drought suggest that this species can maintain high productivity longer than other ecosystems during a drought at the expense of water use. While miscanthus maintained productivity during drought, recovery lagged associated with depleted soil moisture. The enhanced ET of miscanthus may intensify droughts through increase supply of deep soil moisture to the atmosphere.
Experimental investigation of the LiAlSi2O6‐MgSiO3 and LiAlSi2O6‐CaMgSi2O6 isopleths at 1 atm
Authors: Konar Bikram , Hudon Pierre , Jung In‐Ho 
Published: April 2017

AbstractThe phase diagrams of the LiAlSi2O6‐MgSiO3 and LiAlSi2O6‐CaMgSi2O6 isopleths were experimentally investigated at 1 atm using the quenching method and differential scanning calorimetry and the phases produced were characterized with the help of X‐ray diffraction and electron probe microanalysis. With the help of thermodynamic optimization, the phase diagrams of both systems were more accurately reported. No detectable solubility of Li2O in diopside and enstatite was found. However, both systems are not simple binary eutectic systems because their phase equilibria are somewhat complex due to the presence of some β‐spodumene solid solution. In the β‐spodumene solid solution, no notable solubility of MgO and CaO was detected; evidence of significant solubility of SiO2 was confirmed.
Hydrothermal formation and up‐conversion luminescence of Er3+‐doped GdNbO4
Authors: Hirano Masanori , Ishikawa Katsuya 
Published: April 2017

AbstractThe effect of concentration of Er3+ on the up‐conversion and photoluminescence properties of Gd1.00−xErxNbO4, x=0‐0.50 which has monoclinic fergusonite‐type structure as a main phase has been investigated, using a processing technique based on hydrothermal method. Under weakly basic hydrothermal condition at 240°C for 5 hours, a single phase of fergusonite‐type Gd1.00−xErxNbO4 solid solution was directly formed as nanocrystals by the substitutional incorporation of Er3+ into GdNbO4 because of the gradual and linear decrease in the lattice parameters of the monoclinic phase corresponding to the Vegard's Law. The gadolinium niobate doped with 2 mol% Er3+, Gd0.98Er0.02NbO4 after heating at 1300°C for 1 hour, which has nanocrystalline structure whose crystallite size is around 29 nm, exhibits the highest photoluminescence intensity in the green spectral region, 515‐560 nm under excitation at wavelength of 254 nm. On the other hand, the up‐converted luminescence intensity of the niobate nanocrystals becomes the maximum at the concentration of 20 mol% Er3+, Gd0.80Er0.20NbO4 under excitation at 980 nm. These results demonstrate that the material, Er3+‐doped GdNbO4 nanocrystals prepared through hydrothermal route and postheating has potential for up‐converting phosphor.
Low‐temperature aging of baddeleyite‐based Ca‐TZP ceramics
Authors: Zhigachev Andrey O. , Umrikhin Alexey V. , Korenkov Viktor V. , Golovin Yuri I. 
Published: April 2017

AbstractThe aging kinetics during low‐temperature aging of calcia‐stabilized tetragonal zirconia polycrystal (Ca‐TZP) ceramics prepared by high‐energy milling of natural zirconia mineral (baddeleyite) was studied by X‐ray diffraction under hydrothermal treatment conditions. Aging kinetics was investigated for ceramics with different contents of calcia. It was found that the kinetics may be well‐described within Johnson‐Mehl‐Avrami‐Kolmogorov model. Model parameters were determined by data fitting procedure. Change in exponential factor within Johnson‐Mehl‐Avrami‐Kolmogorov model with time is shown. Analytical model to describe aging kinetics is proposed. The transformation nucleation rate, initial diameter, and depth of the transformed areas and their growth rates are estimated. Degradation of hardness and fracture toughness is also reported for Ca‐TZP after low‐temperature aging for different contents of the stabilizer.
Understanding the structural origin of crystalline phase transformations in nepheline (NaAlSiO4)‐based glass‐ceramics
Authors: Deshkar Ambar , Marcial José , Southern Scott A. , Kobera Libor , Bryce David L. , McCloy John S. , Goel Ashutosh 
Published: April 2017

AbstractNepheline (Na6K2Al8Si8O32) is a rock‐forming tectosilicate mineral which is by far the most abundant of the feldspathoids. The crystallization in nepheline‐based glass‐ceramics proceeds through several polymorphic transformations — mainly orthorhombic, hexagonal, cubic — depending on their thermochemistry. However, the fundamental science governing these transformations is poorly understood. In this article, an attempt has been made to elucidate the structural drivers controlling these polymorphic transformations in nepheline‐based glass‐ceramics. Accordingly, two different sets of glasses (meta‐aluminous and per‐alkaline) have been designed in the system Na2O–CaO–Al2O3–SiO2 in the crystallization field of nepheline and synthesized by the melt‐quench technique. The detailed structural analysis of glasses has been performed by 29Si, 27Al, and 23Na magic‐angle spinning — nuclear magnetic resonance (MAS NMR), and multiple‐quantum MAS NMR spectroscopy, while the crystalline phase transformations in these glasses have been studied under isothermal and non‐isothermal conditions using differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and MQMAS NMR. Results indicate that the sequence of polymorphic phase transformations in these glass‐ceramics is dictated by the compositional chemistry of the parent glasses and the local environments of different species in the glass structure; for example, the sodium environment in glasses became highly ordered with decreasing Na2O/CaO ratio, thus favoring the formation of hexagonal nepheline, while the cubic polymorph was the stable phase in SiO2–poor glass‐ceramics with (Na2O+CaO)/Al2O3 > 1. The structural origins of these crystalline phase transformations have been discussed in the paper.
Thermally‐induced phase transformations in Na0.5Bi0.5TiO3–KNbO3 ceramics
Authors: Wang Ge , Li Yizhe , Murray Claire A. , Tang Chiu C. , Hall David A. 
Published: April 2017

AbstractThe structures and functional properties of Na0.5Bi0.5TiO3–xKNbO3 (NBT‐xKN) solid solutions, with x in the range from 0.01 to 0.09, were investigated using a combination of high‐resolution synchrotron X‐ray powder diffraction (SXPD) and ferroelectric property measurements. For low KN contents, an irreversible transformation from cubic to rhombohedral phases was observed after the application of a high electric field, indicating that the polar nanoregions (PNRs) in the unpoled state can be transformed into metastable long‐range ordered ferroelectric domains in the poled state. In contrast, the near‐cubic phase of the unpoled ceramics was found to be remarkably stable and was retained on cooling to a temperature of −175°C. Upon heating, the field‐induced metastable ferroelectric rhombohedral phase transformed back to the nanopolar cubic state at the structural transformation temperature, TST, which was determined as approximately 225°C and 125°C for KN contents of 3% and 5% respectively. For the field‐induced rhombohedral phase in the poled specimens, the pseudo‐cubic lattice parameter, ap, exhibited an anomalous reduction while the inter‐axial angle increased towards a value of 90° on heating, resulting in an overall increase in volume. The observed structural changes were correlated with the results of temperature‐dependent dielectric, ferroelectric and depolarization measurements, enabling the construction of a phase diagram to define the stable regions of the different ferroelectric phases as a function of composition and temperature.
Composition‐induced structural transitions and enhanced strain response in nonstoichiometric NBT‐based ceramics
Authors: Liu Xing , Li Feng , Zhai Jiwei , Shen Bo , Li Peng , Liu Baihui 
Published: April 2017

AbstractIn this work, the nonstoichiometric 0.99Bi0.505(Na0.8K0.2)0.5‐xTiO3‐0.01SrTiO3 (BNKST(0.5‐x)) ceramics with x=0‐0.03 were synthesized by conventional solid‐state reaction method. The composition‐induced structural transitions were investigated by Raman spectra, dielectric analyses, and electrical measurements. It is found that the relaxor phase can be induced through the modulation of the (Na, K) content. The (Na, K) deficiency in BNKST(0.5‐x) ceramics favors a more disordered local structure and can result in the loss of long‐range ferroelectricity. The x=0.015 critical composition possesses relatively high positive strain Spos of 0.42% and large signal piezoelectric constant d33* of 479 pm V−1 at 6 kV mm−1, along with the good temperature (25‐120°C) and frequency (1‐20 Hz) stability. The recoverable large strain responses in nonstoichiometric ceramics can be attributed to the reversible relaxor‐ferroelectric phase transition, which is closely related to the complex defects (, , and ) and the local random fields. This work may be helpful for the exploration of high‐performance NBT‐based lead‐free materials by means of A‐site compositional modification.
Current understanding and future research directions at the onset of the next century of sintering science and technology
Authors: Bordia Rajendra K. , Kang Suk‐Joong L. , Olevsky Eugene A. 
Published: April 2017

AbstractSintering and accompanying microstructural evolution is inarguably the most important step in the processing of ceramics and hard metals. In this process, an ensemble of particles is converted into a coherent object of controlled density and microstructure at an elevated temperature (but below the melting point) due to the thermodynamic tendency of the particle system to decrease its total surface and interfacial energy. Building on a long development history as a major technological process, sintering remains among the most viable methods of fabricating novel ceramics, including high surface area structures, nanopowder‐based systems, and tailored structural and functional materials. Developing new and perfecting existing sintering techniques is crucial to meet ever‐growing demand for a broad range of technologically significant systems including, for example, fuel and solar cell components, electronic packages and elements for computers and wireless devices, ceramic and metal‐based bioimplants, thermoelectric materials, materials for thermal management, and materials for extreme environments. In this study, the current state of the science and technology of sintering is presented. This study is, however, not a comprehensive review of this extremely broad field. Furthermore, it only focuses on the sintering of ceramics. The fundamentals of sintering, including the thermodynamics and kinetics for solid‐state‐ and liquid‐phase‐sintered systems are described. This study summarizes that the sintering of amorphous ceramics (glasses) is well understood and there is excellent agreement between theory and experiments. For crystalline materials, attention is drawn to the effect of the grain boundary and interface structure on sintering and microstructural evolution, areas that are expected to be significant for future studies. Considerable emphasis is placed on the topics of current research, including the sintering of composites, multilayered systems, microstructure‐based models, multiscale models, sintering under external stresses, and innovative and novel sintering approaches, such as field‐assisted sintering. This study includes the status of these subfields, the outstanding challenges and opportunities, and the outlook of progress in sintering research. Throughout the manuscript, we highlight the important lessons learned from sintering fundamentals and their implementation in practice.
Low‐temperature crystal growth of Yb:Sr5F(PO4)3 without evident thermal runaway
Authors: Liu Yin , Li Yiyu , Wu Yiquan 
Published: April 2017

AbstractSolid‐state single crystal conversion of laser crystal Yb:Sr5F(PO4)3 was investigated to demonstrate the ability to partially convert polycrystals into single crystals without sintering additives, at a temperature below the normal sintering temperature of the material. A threefold increase in crystal growth was observed with the application of an electric field. The enhanced densification was associated with excessive mold radiation and the seed crystal growth was facilitated by reduced grain‐boundary energy in the weak electric field.