bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduction in internal friction in silica glass with high OH content
Authors: Lunin Boris S. , Tokmakov Kirill V. 
Published: November 2018

AbstractThe aim of this article was to investigate processes occurring during annealing of silica glass classified as being of type III (J Non Cryst Solids. 1970;5(2):123‐75). This is an inexpensive silica glass produced by many manufacturers across the globe. However, it can be successfully used for fabrication of high‐Q mechanical resonators. The relationship between residual internal stress and internal friction is elucidated. Quantitative analysis of the structural relaxation kinetics is presented. The influence of the cooling process for structural transformation is also discussed. On the basis of our results, we suggest optimal annealing conditions for minimizing internal friction type III silica glass. The results will be useful for further improvement of the Q‐factor of mechanical resonators, including the test masses of the next generation of gravitational wave detectors. Our approach might, in addition, be used for studying the modification of atomic structure in multicomponent glasses.
A low temperature approach for photo/cathodoluminescent Gd2O2S:Tb (GOS:Tb) nanophosphors
Authors: Wang Xuejiao , Meng Qinghong , Li Meiting , Wang Xiaojun , Wang Zhihao , Zhu Qi , Li Ji‐Guang 
Published: November 2018

AbstractTitrating the aqueous solution of equimolar RE(NO3)3 and (NH4)2SO4 with NH4OH to pH~9 at ~4°C produced an amorphous precursor that yielded phase‐pure and well‐dispersed RE2O2S nanopowder (RE = Gd0.99Tb0.01; GOS:Tb) via a RE2O2SO4 intermediate upon annealing in H2. The powders calcined at the typical temperatures of 700/1200°C exhibited unimodal size distributions and have the average crystallize sizes of ~17/55 nm, average particle sizes of ~284/420 nm, and specific surface areas of ~14.62/4.53 m2/g (equivalent particle sizes: ~56/180 nm). The 1200°C product exhibited sharp green luminescence at ~544 nm (FWHM = 2.3 nm; λex = 275 nm), with an absolute quantum yield of ~24.8% and a fluorescence lifetime of ~1.34 ms at room temperature. It was also shown that the powder possesses favorable thermal stability (the activation energy for thermal quenching of luminescence ~0.305 eV) and is stable under electron beam irradiation up to 7 kV and 50 μA. The synthetic technique has the advantages of scalability and favorable dispersion and high chemical/phase purity for GOS powder, which may allow the sintering of scintillation ceramics at lower temperatures.
Composition‐driven broad phase boundary for optimizing properties and stability in lead‐free barium titanate ceramics
Authors: Zhao Chunlin , Wu Bo , Wu Jiagang 
Published: November 2018

AbstractA new piezoelectric system of (1−x−y)BaTiO3‐yCaZrO3‐xBaSnO3 (BT‐yCZ‐xBS) was designed to achieve enhanced piezoelectric/strain properties and temperature stability. First, the relationships between composition, phase, and electrical properties are systematically investigated. The broad phase boundary with successive rhombohedral‐orthorhombic (R‐O) and orthorhombic‐tetragonal (O‐T) was obtained in 0.04 ≤ x ≤ 0.05 and 0.04 ≤ y ≤ 0.07 by tailoring the relationship of composition and phase structure, confirmed by X‐ray diffraction, temperature‐dependent dielectric constants, and Raman spectra. The optimized piezoelectric coefficient of d33 = 560 pC/N, high strain of >0.20%, and large converse piezoelectric coefficient of d33* = 1170 pm/V were realized. Second, the optimized piezoelectricity both demonstrate a stable performance with fluctuation <8% for d33* and 20% for d33 between 22 and 60°C since the broad phase boundary is exhibited in this temperature range. We believe that this work is a successful example to optimize piezoelectric properties and enhance the stability for piezoceramics.
African shrub distribution emerges via a trade‐off between height and sapwood conductivity
Authors: Gaillard Camille , Langan Liam , Pfeiffer Mirjam , Kumar Dushyant , Martens Carola , Higgins Steven I. , Scheiter Simon 
Published: November 2018

AbstractAimShrubs are multistemmed woody plants and are a successful growth form in many ecosystems globally. Ecosystems such as the Fynbos in South Africa or mediterranean shrublands are dominated by a dense shrub cover. In savannas, shrubs are a major vegetation component. Despite the importance of shrubs at the global scale, they are, in contrast to trees, often understudied both in empirical and modelling studies. We define shrub and tree strategies by a trade‐off between water uptake capacity and height growth, and aim to explore if this trade‐off allows us to explain shrub distribution.LocationSub‐Saharan AfricaMethodsWe improve a dynamic vegetation model, the adaptive Dynamic Global Vegetation Model version 2 (aDGVM2), to simulate shrubs as multistemmed woody plants, based on a trade‐off between rapid height growth in single‐stemmed trees and efficient water uptake in multistemmed shrubs.ResultsWe show that, in aDGVM2, (a) the implemented trade‐off allows a multistemmed shrub strategy to emerge and is sufficient to simulate the broad distribution of shrubs in African savannas; (b) fire and aridity promote shrubs at the expense of trees and grasses; and (c) the presence of shrubs influences competitive interactions between grasses and woody vegetation.Main conclusionWe provide a novel approach to simulate shrubs in a dynamic vegetation model. This approach enhances our understanding of the distribution of shrubs, but further work is required for arid and mediterranean shrublands. We conclude that introducing fundamental trade‐offs between growth forms into vegetation models can improve vegetation representation.
The theory of island biogeography, the sample‐area effect, and the habitat diversity hypothesis: complementarity in a naturally fragmented landscape of lake islands
Authors: MacDonald Zachary G. , Anderson Iraleigh D. , Acorn John H. , Nielsen Scott E. 
Published: November 2018

AbstractAimInvestigate relationships between fragmentation and species diversity in the context of the theory of island biogeography, sample‐area effect, and habitat diversity hypothesis.LocationLake of the Woods, Canada.TaxonVascular plantsMethodsVascular plant species diversity was inventoried on 30 islands, organized into two island sets. Each island set contained four size classes that varied in degree of fragmentation while controlling for the sample‐area effect (small island set: 8 × 0.1‐ha, 4 × 0.2‐ha, 2 × 0.4‐ha, and 1 × 0.8‐ha islands; large island set: identical pattern utilizing 1.0‐ha to 8.0‐ha islands). Fragmentation effects were then examined usingSLOSS‐based analyses, addressing whether single large or several small islands contained more species/habitats: (a) direct comparisons of species and habitat richness across size classes; (b) extrapolations of species–area relationships; and (c) analyses of species and habitat accumulation curves. Multigroup path analysis was next used to quantify effects of habitat diversity, island area, and isolation on species richness for both island sets. Finally, pairwise and multiple‐site dissimilarity was estimated for both species and habitats across 0.1‐ha and 1.0‐ha islands to investigate whether: (a) variation in species composition was related to habitat composition; and (b) species dissimilarity increased with inter‐island distance.ResultsSLOSS‐based analyses indicated that several small islands contained more species than single large islands in both island sets. This pattern was also observed for habitats, but only in the small islands set. Path analysis suggested that island area had significant direct and indirect (mediated by habitat diversity) effects on species richness. Habitat diversity and island isolation had significant positive and negative effects on species richness, respectively, independent of island area. Species and habitat dissimilarities were significantly related across 0.1‐ha but not 1.0‐ha islands, and showed no relationship to inter‐island distance.Main conclusionsThe overall positive relationship between fragmentation and species richness may be attributed to greater habitat diversity and increased species dissimilarity across smaller islands relative to larger islands. However, negative isolation effects indicate that landscape configuration is still an important conservation consideration. These results each align with different predictions of the theory of island biogeography, sample‐area effect, and habitat diversity hypothesis, questioning the exclusivity of these theoretical frameworks.
Climatic niche evolution in turtles is characterized by phylogenetic conservatism for both aquatic and terrestrial species
Authors: Rodrigues João Fabrício M. , Villalobos Fabricio , Iverson John B. , Diniz‐Filho José Alexandre F. 
Published: November 2018

AbstractUnderstanding how the climatic niche of species evolved has been a topic of high interest in current theoretical and applied macroecological studies. However, little is known regarding how species traits might influence climatic niche evolution. Here, we evaluated patterns of climatic niche evolution in turtles (tortoises and freshwater turtles) and whether species habitat (terrestrial or aquatic) influences these patterns. We used phylogenetic, climatic and distribution data for 261 species to estimate their climatic niches. Then, we compared whether niche overlap between sister species was higher than between random species pairs and evaluated whether niche optima and rates varied between aquatic and terrestrial species. Sister species had higher values of niche overlap than random species pairs, suggesting phylogenetic climatic niche conservatism in turtles. The climatic niche evolution of the group followed an Ornstein–Uhlenbeck model with different optimum values for aquatic and terrestrial species, but we did not find consistent evidence of differences in their rates of climatic niche evolution. We conclude that phylogenetic climatic niche conservatism occurs among turtle species. Furthermore, terrestrial and aquatic species occupy different climatic niches but these seem to have evolved at similar evolutionary rates, reinforcing the importance of habitat in understanding species climatic niches and their evolution.
Harsh conditions during early development influence telomere length in an altricial passerine: Links with oxidative stress and corticosteroids
Authors: Gil Diego , Alfonso‐Iñiguez Sergio , Pérez‐Rodríguez Lorenzo , Muriel Jaime , Monclús Raquel 
Published: November 2018

AbstractStress during early development can induce substantial long‐term effects in organisms. In the case of birds, despite growth compensations, nestlings reared under harsh conditions typically show reduced survival chances in adulthood. It has been proposed that environmental early‐life stressors could affect longevity via effects on telomere length, possibly mediated through oxidative stress. However, the link between these processes is not clear. In this study, we experimentally manipulated brood size in spotless starlings (Sturnus unicolor) to test the causal relationship between early stress, oxidative and corticosterone‐mediated stress and telomere shortening. Our results show that experimentally enlarged brood sizes led to a reduction in morphometric development on nestlings, the effect being stronger for females than males. Additionally, basal corticosterone levels increased with increasing brood size in female nestlings. Neither plasma antioxidant status nor malondialdehyde levels (a marker of lipid peroxidation) were affected by experimental brood size, although the levels of a key intracellular antioxidant (glutathione) decreased with increasing brood size. We found that the treatment showed a quadratic effect on nestling telomere lengths: these were shortened either by increases or by decreases in the original brood size. Our study provides experimental evidence for a link between developmental stress and telomere length, but does not support a direct causal link of this reduction with corticosterone or oxidative stress. We suggest that future studies should focus on how telomere length responds to additional markers of allostatic load.
Quality Assessment and Circularity Potential of Recovery Systems for Household Plastic Waste
Authors: Eriksen Marie Kampmann , Damgaard Anders , Boldrin Alessio , Astrup Thomas Fruergaard 
Published: November 2018

SummaryPlastic recycling is promoted in the transition toward a circular economy and a closed plastic loop, typically using mass‐based recycling targets. Plastic from household waste (HHW) is contaminated and heterogeneous, and recycled plastic from HHW often has a limited application range, due to reduced quality. To correctly assess the ability to close plastic loops via recycling, both plastic quantities and qualities need to be evaluated. This study defines a circularity potential representing the ability of a recovery system to close material loops assuming steady‐state market conditions. Based on an average plastic waste composition including impurities, 84 recovery scenarios representing a wide range of sorting schemes, source‐separation efficiencies, and material recovery facility (MRF) configurations and performances were assessed. The qualities of the recovered fractions were assessed based on contamination and the circularity potential calculated for each scenario in a European context. Across all scenarios, 17% to 100% of the generated plastic mass could be recovered, with higher source‐separation and MRF efficiencies leading to higher recovery. Including quality, however, at best 55% of the generated plastic was suitable for recycling due to contamination. Source‐separation, a high number of target fractions, and efficient MRF recovery were found to be critical. The circularity potential illustrated that less than 42% of the plastic loop can be closed with current technology and raw material demands. Hence, Europe is still far from able to close the plastic loop. When transitioning toward a circular economy, the focus should be on limiting impurities and losses through product design, technology improvement, and more targeted plastic waste management.
Decrease in DNA methylation 1 (DDM1) is required for the formation of mCHH islands in maize
Authors: Long Jin Cheng , Xia Ai Ai , Liu Jing Han , Jing Ju Li , Wang Ya Zhong , Qi Chuang Ye , He Yan 
Published: November 2018

AbstractDNA methylation plays a crucial role in suppressing mobilization of transposable elements and regulation of gene expression. A number of studies have indicated that DNA methylation pathways and patterns exhibit distinct properties in different species, including Arabidopsis, rice, and maize. Here, we characterized the function of DDM1 in regulating genome‐wide DNA methylation in maize. Two homologs of ZmDDM1 are abundantly expressed in the embryo and their simultaneous disruption caused embryo lethality with abnormalities in cell proliferation from the early stage of kernel development. We establish that ZmDDM1 is critical for DNA methylation, at CHG sites, and to a lesser extent at CG sites, in heterochromatic regions, and unexpectedly, it is required for the formation of mCHH islands. In addition, ZmDDM1 is indispensable for the presence of 24‐nt siRNA, suggesting its involvement in the RdDM pathway. Our results provide novel insight into the role of ZmDDM1 in regulating the formation of mCHH islands, via the RdDM pathway maize, suggesting that, in comparison to Arabidopsis, maize may have adopted distinct mechanisms for regulating mCHH.
BeyondHomo Entrepreneurus: Judgment and the Theory of Cultural Entrepreneurship
Authors: Lounsbury Michael , Gehman Joel , Ann Glynn Mary 
Published: November 2018

AbstractIn this paper, we embrace the critique of the contemporary entrepreneurship literature offered by Foss, Klein, and Bjørnskov, and applaud their advance of the Judgment‐Based Approach (JBA) as a way to broaden our understanding of entrepreneurial processes by contextualizing entrepreneurial action. However, we believe that to attain the promise of the JBA, a broader inter‐disciplinary engagement beyond economics is required. Drawing on theory and arguments in the cultural entrepreneurship literature, we emphasize the fruitfulness of foregrounding the role of culture – a theoretical focus that is marginalized both in the mainstream entrepreneurship literature and in the JBA. We compare the JBA and the Theory of Cultural Entrepreneurship and outline how a wider inter‐disciplinary research agenda could be advanced in entrepreneurial studies.
Changes in masticatory performance of edentulous patients treated with single‐implant mandibular overdentures and conventional complete dentures
Authors: Nogueira Túlio E. , Schimmel Martin , Leles Cláudio R. 
Published: November 2018

SummaryObjectivesThe aim of this study was to test the effect of a single‐implant mandibular overdenture (SIMO), compared with conventional complete denture (CD), on masticatory performance measured by the mixing ability of a two‐coloured chewing gum.MethodsA sample of edentulous subjects was randomly assigned to the SIMO (n = 15) and CD (n = 19) groups. Patients in both groups received a set of new complete dentures, and the SIMO group received a single implant in the symphyseal region of the mandible (Straumann® Standard Plus SLActive®) and an eliptical matrix and ball attachment for denture retention. Masticatory tests were performed using a two‐colour chewing gum (Vivident Fruitswing, Perfetti van Melle, Turkey) for 20 and 50 chewing cycles. Colour‐mixing ability was assessed by electronic colourimetric analysis (ViewGum©, Dhal Software, Greece), expressed by the variance of hue. Tests were performed at baseline and at the 6‐ and 12‐month follow‐ups. Multilevel linear regression was used to model the changes in masticatory performance.ResultsGroups were similar at baseline for 20 and 50 cycles (P > 0.05). A significant linear effect was observed on time points for 20 and 50 cycles (P < 0.001). No difference was observed between treatment groups factor (P > 0.05). However, the way masticatory performance varied according to time points differed in the CD and SIMO groups for 20 cycles (P = 0.048).ConclusionMasticatory performance improved significantly after 12 months, irrespective to the insertion of a single implant to retain a mandibular overdenture. Moreover, results suggest that SIMO treatment may perform better than CD in the shorter follow‐up period.
Endogenous pain modulation in chronic temporomandibular disorders: Derivation of pain modulation profiles and assessment of its relationship with clinical characteristics
Authors: Moana‐Filho Estephan J. , Herrero Babiloni Alberto 
Published: November 2018

SummaryBackgroundEndogenous pain modulation (EPM) reflects the brain's ability to modulate incoming nociceptive inputs, and deficient EPM was implicated as a chronic pain mechanism. EPM status has been investigated in temporomandibular disorders (TMD) patients with conflicting results, and its relationship with clinical characteristics in this population is not well known.Objectives(a) Determine EPM responses in chronic TMD cases and pain‐free controls; (b) Derive pain modulation profiles (PMP) based on individual EPM responses; and (c) Categorise clinical characteristics of TMD cases and pain‐free controls based on their individual PMP.MethodsTwenty‐two chronic TMD cases and 17 age‐matched pain‐free controls, all females, were comprehensively characterised regarding clinical characteristics and underwent EPM testing using temporal summation of pain (TSP) and conditioned pain modulation (CPM) protocols over the face and hand. Individuals were categorised into PMPs (I‐IV) based on predetermined cut‐off points for TSP and CPM responses.ResultsBetween‐group comparisons showed similar TSP and CPM responses (P > 0.23) in the face, while TMD cases showed significantly increased TSP (P = 0.04) but similar CPM responses (P > 0.17) in the hand relative to controls. Similar distribution across PMPs and clinical characteristics when categorised into PMPs was found for both groups. Body mass index was associated with increased TSP and reduced CPM in the face in TMD cases.ConclusionEndogenous pain modulation responses over the face were similar between groups. TMD cases showed increased hand TSP compared to controls while both groups showed no significant hand CPM. PMP classification showed similar results between groups, and further refinement of PMP determination is warranted.
Fertility, retirement age, and pay‐as‐you‐go pensions
Authors: Chen Hung‐Ju 
Published: November 2018

AbstractThis paper develops an overlapping generations model with exogenous and endogenous retirement age to examine the effects of fertility and retirement age on long‐run pay‐as‐you‐go pensions. For both cases, we find that pensions may not necessarily increase with the fertility rate. In the case with exogenous retirement age, a higher fertility rate (retirement age) raises (reduces) pension benefits if the fertility rate and official pension age are low, whereas this result reverses otherwise. In the case with endogenous retirement age, a higher fertility rate raises pensions if the fertility rate and costs of raising children are low; otherwise, such a change decreases pensions. Our numerical results indicate that, under a reasonable range of parameterization, raising the fertility rate is more likely to increase pensions in the case with exogenous retirement age, whereas such a change tends to reduce pensions in the case with endogenous retirement age.
Evaluation of plasma concentration after intravenous and intramuscular penicillin administration over 24 hr in healthy adult horses
Authors: Younkin Jarrod T. , Santschi Elizabeth M. , Kukanich Butch , Lubbers Brian V. , Warner Matthew 
Published: November 2018

AbstractPenicillin is administered intravenously (IV) or intramuscularly (IM) to horses for the prevention and treatment of infections, and both routes have disadvantages. To minimize these shortcomings, a 24‐hr hybrid administration protocol (HPP) was developed. Our objective was to determine penicillin plasma concentrations in horses administered via HPP. Venous blood was collected from seven healthy horses administered IV potassium penicillin G at 0 and 6 hr and IM procaine penicillin G at 12 hr. Blood was collected at 2‐hr intervals from 0 to 20 hr and at 24 hr. Plasma penicillin concentrations were measured using liquid chromatography and mass spectrometry. Penicillin susceptibility from equine isolates was examined to determine pharmacodynamic targets. The MIC90 of penicillin for 264 isolates of Streptococcus sp. was ≤0.06 μg/ml. For the 24‐hr dosing interval, the mean plasma penicillin concentration was >0.07 μg/ml. Five horses (72%) exceeded 0.06 μg/ml for 98% of the dosing interval, and two horses exceeded this value for 52%–65% of the dosing interval. The HPP achieved mean plasma penicillin concentrations in healthy adult horses above 0.07 μg/ml for a 24‐hr dosing interval. However, individual variations in plasma concentrations were apparent and deserve future clinical study.