bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactive Molecular Dynamics Simulations of the Thermal Decomposition Mechanism of 1,3,3‐Trinitroazetidine
Authors: Junying WU , Yanxi HUANG , Lijun YANG , Deshen GENG , Fuping WANG , Heqi WANG , Lang CHEN 
Published: July 2018

Abstract1,3,3‐Trinitroazetidine (TNAZ) has a molecular formula of C3H4N4O6 and the characteristics of low melting point, low impact sensitivity and good thermal stability. It is suitable for melt casting and pressed charges, and it has broad prospects for applications in low‐sensitivity ammunition. In this study, the thermal decomposition of TNAZ crystals at high temperature was calculated by molecular dynamics simulation with the ReaxFF/lg reactive force field. The change in the potential energy of TNAZ, the formation of small‐molecule products and clusters, and the initial reaction path of TNAZ were analysed. The kinetic parameters of different reaction stages in TNAZ thermal decomposition were obtained. The primary thermal decomposition reaction of TNAZ was found to be as follows: N−NO2 and C−NO2 bonds broke; a H atom on the quaternary ring was transferred to the nitro group; and the C‐HNO2 and N‐HNO2 bonds broke. The main decomposition products of TNAZ were thus NO2, NO, N2, H2O, CO2 and HNO2, as well as macromolecular clusters. The size of the cluster structure was related to the reaction temperature, and the higher the temperature was, the smaller the cluster size was.
3D Edge‐Enriched Fe3C@C Nanocrystals with a Core–Shell Structure Grown on Reduced Graphene Oxide Networks for Efficient Oxygen Reduction Reaction
Authors: Li Jianyang , Mao Shun , Hou Yang , Lei Lecheng , Yuan Chris 
Published: July 2018

AbstractThe design of highly active, stable, and low‐cost oxygen reduction reaction (ORR) electrocatalysts to replace platinum‐based materials is crucial to the development of renewable energy technologies. Herein, novel 3D edge‐enriched Fe3C@C nanocrystals with a core–shell structure grown on reduced graphene oxide (rGO) networks (Fe3C@C/rGO) are reported as highly efficient and stable electrocatalysts for the ORR. The rGO nanosheets act as a host and provide vital support for local growth of edge‐enriched Fe3C@C nanocrystals, leading to a large surface area of 263 m2 g−1 and superstable hybrid structure. The unique structural design of the Fe3C@C/rGO hybrid enables fast mass transport and a substantial number of exposed active edge sites for electrocatalytic reaction. The Fe3C@C/rGO hybrid exhibits excellent ORR catalytic activity, with a high positive onset potential close to 1.0 V, a Tafel slope of 65 mV dec−1, and excellent durability with only about 8 % current density decay at 0.8 V after 20 000 s continuous operation, which is superior to that of commercial Pt/C catalyst in an alkaline electrolyte.
Sea‐level rise, habitat loss, and potential extirpation of a salt marsh specialist bird in urbanized landscapes
Authors: Rosencranz Jordan A. , Thorne Karen M. , Buffington Kevin J. , Takekawa John Y. , Hechinger Ryan F. , Stewart Tara E. , Ambrose Richard F. , MacDonald Glen M. , Holmgren Mark A. , Crooks Jeff A. , Patton Robert T. , Lafferty Kevin D. 
Published: July 2018

AbstractSea‐level rise (SLR) impacts on intertidal habitat depend on coastal topology, accretion, and constraints from surrounding development. Such habitat changes might affect species like Belding's savannah sparrows (Passerculus sandwichensis beldingi; BSSP), which live in high‐elevation salt marsh in the Southern California Bight. To predict how BSSP habitat might change under various SLR scenarios, we first constructed a suitability model by matching bird observations with elevation. We then mapped current BSSP breeding and foraging habitat at six estuarine sites by applying the elevation‐suitability model to digital elevation models. To estimate changes in digital elevation models under different SLR scenarios, we used a site‐specific, one‐dimensional elevation model (wetland accretion rate model of ecosystem resilience). We then applied our elevation‐suitability model to the projected digital elevation models. The resulting maps suggest that suitable breeding and foraging habitat could decline as increased inundation converts middle‐ and high‐elevation suitable habitat to mudflat and subtidal zones. As a result, the highest SLR scenario predicted that no suitable breeding or foraging habitat would remain at any site by 2100 and 2110. Removing development constraints to facilitate landward migration of high salt marsh, or redistributing dredge spoils to replace submerged habitat, might create future high salt marsh habitat, thereby reducing extirpation risk for BSSP in southern California.
High levels of multiple paternity in a spermcast mating freshwater mussel
Authors: Wacker Sebastian , Larsen Bjørn Mejdell , Jakobsen Per , Karlsson Sten 
Published: July 2018

AbstractMultiple paternity is an important characteristic of the genetic mating system and common across a wide range of taxa. Multiple paternity can increase within‐population genotypic diversity, allowing selection to act on a wider spectre of genotypes, and potentially increasing effective population size. While the genetic mating system has been studied in many species with active mating behavior, little is known about multiple paternity in sessile species releasing gametes into the water. In freshwater mussels, males release sperm into the water, while eggs are retained and fertilized inside the female (spermcast mating). Mature parasitic glochidia are released into the water and attach to the gills of fish where they are encapsulated until settling in the bottom substrate. We used 15 microsatellite markers to detect multiple paternity in a wild population of the freshwater pearl mussel (Margaritifera margaritifera). We found multiple paternity in all clutches for which more than two offspring were genotyped, and numbers of sires were extremely high. Thirty‐two sires had contributed to the largest clutch (43 offspring sampled). This study provides the first evidence of multiple paternity in the freshwater pearl mussel, a species that has experienced dramatic declines across Europe. Previous studies on other species of freshwater mussels have detected much lower numbers of sires. Multiple paternity in freshwater pearl mussels may be central for maintaining genetic variability in small and fragmented populations and for their potential to recover after habitat restoration and may also be important in the evolutionary arms race with their fish host with a much shorter generation time.
Latitudinal effects on crown shape evolution
Authors: Lindh Magnus , Falster Daniel S. , Zhang Lai , Dieckmann Ulf , Brännström Åke 
Published: July 2018

AbstractLarge variations in crown shape are observed across the globe, from plants with wide and deep crowns to those with leaves clustered at the top. While there have been advances in the large‐scale monitoring of forests, little is known about factors driving variations in crown shape with environmental conditions. Previous theoretical research suggests a gradient in crown shape with latitude, due to the effects of sun angle. Yet, it remains unclear whether such changes are also predicted under competition. Using a size‐structured forest‐growth model that incorporates self‐shading from plants and competitive shading from their neighbors, we investigate how changes in site productivity and sun angle shape crown evolution. We consider evolution in two traits describing the top‐heaviness and width‐to‐height ratio of crowns, shaped by trade‐offs reflecting the costs and benefits of alternative architectures. In top‐heavy trees, most of the leaves are at the top half of the trunk. We show that, contrary to common belief, the angle of sun beams per se has only a weak influence on crown shapes, except at low site productivity. By contrast, reduced site productivity has a strong effect, with trees growing in less productive sites keeping their leaves closer to the ground. The crown width‐to‐height ratio is generally higher at a lower site productivity, but this trait is not strongly influenced by any environmental factor. This theoretical analysis brings into question established beliefs about the effects of latitude on crown shapes. By introducing geometry‐related growth constraints caused by shading from both the surrounding forest and the tree on itself, and costs for constructing and maintaining a three‐dimensional crown, our analysis suggests crown shapes may vary with latitude, mostly via effects on overall site productivity, and less because of the angle of the sun.
RAD sequencing resolved phylogenetic relationships in European shrub willows (Salix L. subg. Chamaetia and subg. Vetrix) and revealed multiple evolution of dwarf shrubs
Authors: Wagner Natascha Dorothea , Gramlich Susanne , Hörandl Elvira 
Published: July 2018

AbstractThe large and diverse genus Salix L. is of particular interest for decades of biological research. However, despite the morphological plasticity, the reconstruction of phylogenetic relationships was so far hampered by the lack of informative molecular markers. Infrageneric classification based on morphology separates dwarf shrubs (subg. Chamaetia) and taller shrubs (subg. Vetrix), while previous phylogenetic studies placed species of these two subgenera just in one largely unresolved clade. Here we want to test the utility of genomic RAD sequencing markers for resolving relationships at different levels of divergence in Salix. Based on a sampling of 15 European species representing 13 sections of the two subgenera, we used five different RAD sequencing datasets generated by Ipyrad to conduct phylogenetic analyses. Additionally we reconstructed the evolution of growth form and analyzed the genetic composition of the whole clade. The results showed fully resolved trees in both ML and BI analysis with high statistical support. The two subgenera Chamaetia and Vetrix were recognized as nonmonophyletic, which suggests that they should be merged. Within the Vetrix/Chamaetia clade, a division into three major subclades could be observed. All species were confirmed to be monophyletic. Based on our data, arctic‐alpine dwarf shrubs evolved four times independently. The structure analysis showed five mainly uniform genetic clusters which are congruent in sister relationships observed in the phylogenies. Our study confirmed RAD sequencing as a useful genomic tool for the reconstruction of relationships on different taxonomic levels in the genus Salix.
Sexual and temporal variations in floral scent in the subdioecious shrub Eurya japonica Thunb
Authors: Wang Hui , Zheng Peiming , Aoki Dan , Miyake Takashi , Yagami Sachie , Matsushita Yasuyuki , Fukushima Kazuhiko , Nakagawa Michiko 
Published: July 2018

AbstractIn many flowering plants, floral scents are a significant trait for visitors, playing an important role in attracting pollinators and/or detracting herbivores. The evolution of flowering plants from hermaphroditism to dioecy is often accompanied by sexual dimorphism in floral scent. In this study, floral scents emitted by different sexual morphs of the subdioecious shrub Eurya japonica Thunb. were collected using a dynamic headspace method, and sexual and temporal variations were evaluated by gas chromatography–mass spectrometry (GC–MS). Two volatiles, α‐pinene and linalool, were identified as the major components of floral scents in females, hermaphrodites, and males. The males emit higher amounts of floral scents, particularly α‐pinene, compared to females or hermaphrodites. Floral scents emitted by males generally decrease as flowers enter senescence, whereas those from females or hermaphrodites do not significantly differ. Intraspecific variations in floral scents of subdioecious species provided by this study would contribute to better understanding of sexual dimorphism in floral scent.
Human activities accelerated the degradation of saline seepweed red beaches by amplifying top‐down and bottom‐up forces
Authors: Lu Weizhi , Xiao Jingfeng , Lei Wei , Du Jinqiu , Li Zhengjie , Cong Pifu , Hou Wenhao , Zhang Jialin , Chen Luzhen , Zhang Yihui , Liao Guoxiang 
Published: July 2018

AbstractSalt marshes dominated by saline seepweed (Suaeda heteroptera) provide important ecosystem services such as sequestering carbon (blue carbon), maintaining healthy fisheries, and protecting shorelines. These salt marshes also constitute stunning red beach landscapes, and the resulting tourism significantly contributes to the local economy. However, land use change and degradation have led to a substantial loss of the red beach area. It remains unclear how human activities influence the top‐down and bottom‐up forces that regulate the distribution and succession of these salt marshes and lead to the degradation of the red beaches. We examined how bottom‐up forces influenced the germination, emergence, and colonization of saline seepweed with field measurements and a laboratory experiment. We also examined whether top‐down forces affected the red beach distribution by conducting a field survey for crab burrows and density, laboratory feeding trials, and waterbird investigations. The higher sediment accretion rate induced by human activities limited the establishment of new red beaches. The construction of tourism facilities and the frequent presence of tourists reduced the density of waterbirds, which in turn increased the density of crabs, intensifying the top‐down forces such as predators and herbivores that drive the degradation of the coastal red beaches. Our results show that sediment accretion and plant–herbivory changes induced by human activities were likely the two primary ecological processes leading to the degradation of the red beaches. Human activities significantly shaped the abundance and distribution of the red beaches by altering both top‐down and bottom‐up ecological processes. Our findings can help us better understand the dynamics of salt marshes and have implications for the management and restoration of coastal wetlands.
Species richness and turnover among indigenous and introduced plants and insects of the Southern Ocean Islands
Authors: Leihy Rachel I. , Duffy Grant A. , Chown Steven L. 
Published: July 2018

AbstractSimultaneously investigating variation in species richness and turnover for indigenous and introduced communities holds great promise as a means to understand the relative contributions of ecological processes to community structure. Such insight will advance understanding of the ways in which environmental change may affect future community dynamics. Using a recently developed multi‐site turnover metric, zeta diversity (ζ), we explored species turnover patterns across indigenous and introduced insect and vascular plant communities of the Southern Ocean Islands. In addition, we used updated species occurrence and high‐resolution environmental data to reexamine previously described patterns and drivers of species richness across the region. Species richness variation in indigenous insect and vascular plant communities was largely explained by island isolation and temperature, whereas human visitation frequency was strongly associated with introduced species diversity of both groups. Indigenous communities of both plants and insects had faster rates of species turnover across sites and less inter‐island connectivity than their introduced counterparts. Zeta diversity analyses suggested that stochastic processes were more influential than niche‐related processes on the observed patterns of turnover of indigenous insects. Meanwhile, turnover patterns of introduced insects and indigenous and introduced vascular plants were indicative of the dominance of niche‐related processes. These outcomes highlight very different diversity patterns across indigenous and alien communities and indicate that different ecological processes may underlie diversity variation across these islands and taxonomic groups.
What would you choose: Online or Offline or Mixed services? Feasibility of online HIV counselling and testing among Thai men who have sex with men and transgender women and factors associated with service uptake
Authors: Phanuphak Nittaya , Anand Tarandeep , Jantarapakde Jureeporn , Nitpolprasert Chattiya , Himmad Kanittha , Sungsing Thanthip , Trachunthong Deondara , Phomthong Sangusa , Phoseeta Petchfa , Tongmuang Sumitr , Mingkwanrungruang Pravit , Meekrua Dusita , Sukthongsa Supachai , Hongwiangchan Somporn , Upanun Nutchanin , Barisri Jiranuwat , Pankam Tippawan , Phanuphak Praphan 
Published: July 2018

AbstractIntroductionHIV testing coverage remains low among men who have sex with men (MSM) and transgender women (TGW). We studied characteristics of Thai MSM and TGW who chose online and/or offline platforms for HIV counselling and testing and the feasibility of integrating online technologies and HIV self‐testing to create service options.MethodsFrom December 2015 to June 2017, MSM and TGW enrolled from Bangkok Metropolitan Region and Pattaya could choose between: offline HIV counselling and testing (Offline group), online pre‐test counselling and offline HIV testing (Mixed group), and online counselling and online, supervised, HIV self‐testing (Online group). Sociodemographic data, risk behaviour and social network use characteristics were collected by self‐administered questionnaires. Logistic regression models identified covariates for service preferences.ResultsOf 472 MSM and 99 TGW enrolled, 202 self‐selected the Offline group, 158 preferred the Mixed group, and 211 chose the Online group. The Online group had the highest proportion of first‐time testers (47.3% vs. 42.4% vs. 18.1%, p < 0.001) and reported highest HIV prevalence (15.9% vs. 13.0% vs. 3.4%, p = 0.001) as compared to Offline and Mixed groups, respectively. Having tested for HIV twice or more (OR 2.57, 95% CI 1.03 to 6.41, p = 0.04) increased the likelihood to choose online pre‐test counselling. Being TGW (OR 6.66, 95% CI 2.91 to 15.25, p < 0.001) and using social media from four to eight hours (OR 2.82, 95% CI 1.48 to 5.37, p = 0.002) or >8 hours (OR 2.33, 95% CI 1.05 to 5.16, p = 0.04) increased selection of online, supervised, HIV self‐testing. Providers primarily used smartphones (79.2%) and laptops (37.5%) to deliver online services. Self‐testing strip image sharpness and colour quality were rated “good” to “excellent” by all providers. Most participants (95.1%) agreed that online supervision and HIV self‐testing guidance offered were satisfactory and well delivered.ConclusionsOnline HIV services among MSM and TGW are feasible in Thailand and have the potential to engage high proportions of first‐time testers and those with high HIV prevalence. When designing public health interventions, integrating varied levels of online HIV services are vital to engage specific sections of MSM and TGW populations in HIV services.Clinical Trial NumberNCT03203265
Uptake of HIV self‐testing and linkage to treatment among men who have sex with men (MSM) in Nigeria: A pilot programme using key opinion leaders to reach MSM
Authors: Tun Waimar , Vu Lung , Dirisu Osasuyi , Sekoni Adekemi , Shoyemi Elizabeth , Njab Jean , Ogunsola Sade , Adebajo Sylvia 
Published: July 2018

AbstractIntroductionHIV self‐testing (HIVST) offers an alternative to facility‐based HIV testing services, particularly for populations such as men who have sex with men (MSM) who may fear accessing testing due to stigma, discrimination and criminalization. Innovative HIV testing approaches are needed to meet the goal of 90% of people living with HIV being diagnosed. This study piloted an intervention to distribute oral HIVST kits to MSM through key opinion leaders (KOLs) in Lagos, Nigeria and assessed the feasibility, acceptability, uptake of HIVST and linkage to HIV treatment.MethodsA cohort study was conducted (May through September 2017) with 319 participants who were recruited by 12 KOLs through their networks. A baseline survey was conducted at the time of the oral HIVST kit (OraQuick® HIV antibody test) distribution to eligible MSM followed by a 3‐month follow‐up survey to assess usage of and experience with the HIVST kits. Each participant was given two kits.ResultsThe median age of the participants was 25 years, 88.7% were literate and 17.9% were first‐time testers. Of the 257 participants (80.7% retention) who completed the three‐month follow‐up interview, 97.7% reported using the HIVST kit and 14 (5.6%) self‐reported an HIV positive result. A quarter (22.7%) tested themselves the same day they received the kit, and 49.4% tested within one week. Almost all participants reported that the HIVST kit instructions were easy or somewhat easy to understand (99.6%) and perform the test (98.0%). The most common reasons they liked the test were ease of use (87.3%), confidentiality/privacy (82.1%), convenience (74.1%) and absence of needle pricks (64.9%). All 14 participants who tested positive had sought confirmatory testing and initiated HIV treatment by the time of the three‐month survey.ConclusionsHIVST distribution through KOLs was feasible and oral self‐testing was highly acceptable among this urban MSM population. Despite concerns about linkage to treatment when implementing self‐testing, this study showed that linkage to treatment can be achieved with active follow‐up and access to a trusted MSM‐friendly community clinic that offers HIV treatment. HIVST should be considered as an additional option to standard HIV testing models for MSM.
Changes in engagement in HIV prevention and care services among female sex workers during intensified community mobilization in 3 sites in Zimbabwe, 2011 to 2015
Authors: Ndori‐Mharadze Tendayi , Fearon Elizabeth , Busza Joanna , Dirawo Jeffrey , Musemburi Sithembile , Davey Calum , Acharya Xeno , Mtetwa Sibongile , Hargreaves James R , Cowan Frances 
Published: July 2018

AbstractIntroduction‘Sisters with a Voice’, Zimbabwe's nationally scaled comprehensive programme for female sex workers (FSWs), intensified community mobilization activities in three sites to increase protective behaviours and utilization of clinical services. We compare indicators among FSWs at the beginning and after implementation.MethodsWe used mixed methods to collect data at three sites: in‐depth interviews (n = 22) in 2015, routine clinical data from 2010 to 2015, and two respondent driven sampling surveys in 2011 and 2015, in which participants completed an interviewer‐administered questionnaire and provided a finger prick blood sample for HIV antibody testing. Estimates were weighted using RDS‐1 and estimate convergence assessed in both years. We assessed differences in six indicators between 2011 and 2015 using logistic regression adjusted for age, duration in sex work and education.Results870 FSWs were recruited from the three sites in 2011 and 915 in 2015. Using logistic regression to adjust for socio‐demographic differences, we found higher estimates of the proportion of HIV‐positive FSWs and HIV‐positive FSWs who knew their status and reported being on ART in Mutare and Victoria Falls in 2015 compared to 2011. Reported condom use with clients did not differ by year; however, condom use with regular partners was higher in 2015 in Mutare and Hwange. Reported HIV testing in the last six months among HIV‐negative FSWs was higher in 2015 across sites: for instance, in Victoria Falls it was 13.4% (95% CI 8.7% to 19.9%) in 2011 and 80.8% (95% CI 74.0 to 87.7) in 2015. FSWs described positive perceptions of the Sisters programme, ease of engaging with health services, and improved solidarity among peers. Programme data showed increases in service use by 2015 across all sites.ConclusionsImprovements in key HIV care engagement indicators were observed among FSWs in two sites and in testing and prevention indicators across the three sites after implementation of an intensified community mobilization intervention. Engagement with services for FSWs is critical for countries to reach 90‐90‐90 targets.