bluuebunny/crossref_metadata_2025_split huggingface dataset:
A non‐biased trust model for wireless mesh networks
Authors: Tan Heng Chuan , Ma Maode , Labiod Houda , Chong Peter Han Joo , Zhang Jun 
Published: October 2016

AbstractTrust models that rely on recommendation trusts are vulnerable to badmouthing and ballot‐stuffing attacks. To cope with these attacks, existing trust models use different trust aggregation techniques to process the recommendation trusts and combine them with the direct trust values to form a combined trust value. However, these trust models are biased as recommendation trusts that deviate too much from one's own opinion are discarded. In this paper, we propose a non‐biased trust model that considers every recommendation trusts available regardless they are good or bad. Our trust model is based on a combination of 2 techniques: the dissimilarity test and the Dempster‐Shafer Theory. The dissimilarity test determines the amount of conflict between 2 trust records, whereas the Dempster‐Shafer Theory assigns belief functions based on the results of the dissimilarity test. Numerical results show that our trust model is robust against reputation‐based attacks when compared to trust aggregation techniques such as the linear opinion pooling, subjective logic model, entropy‐based probability model, and regression analysis. In addition, our model has been extensively tested using network simulator NS‐3 in an Infrastructure‐based wireless mesh networks and a Hybrid‐based wireless mesh networks to demonstrate that it can mitigate blackhole and grayhole attacks.
Coexistence of DTV and TV white space systems
Authors: Foo Yee‐Loo , Takada Jun‐ichi 
Published: October 2016

SummaryIt is foreseeable that in near future, heterogeneous TV white space (TVWS) systems will operate in underused TV bands. Potential interference between TVWS systems and digital TV (DTV) broadcast system is a major concern. These TVWS systems need to maintain from the DTV service boundary some keep‐out distances dk, which vary depending on circumstances. This work provides a comprehensive analysis on dk for different TVWS devices that operate on co‐ and adjacent channels, based on 2 different protection criteria for DTV service, using 4 different propagation models (each suits different propagation environment) for estimating dk. In brief, this article contributes to the mathematical technique of determining dk under different circumstances. On the basis of the conditions chosen for the analysis, we come up with some recommendations for dk. Moreover, we share our opinions on some regulatory requirements for dk. The strictness of the regulatory requirement in this matter is important because when it is appropriately set, it can actually promote further development and expansion of TVWS technologies.
Identifying congruence in stream assemblage thresholds in response to nutrient and sediment gradients for limit setting
Authors: Wagenhoff Annika , Clapcott Joanne E. , Lau Kelvin E. M. , Lewis Gillian D. , Young Roger G. 
Published: October 2016

AbstractThe setting of numeric instream objectives (effects‐based criteria) and catchment limits for major agricultural stressors, such as nutrients and fine sediment, is a promising policy instrument to prevent or reduce degradation of stream ecosystem health. We explored the suitability of assemblage thresholds, defined as a point at which a small increase in a stressor will result in a disproportionally large change in assemblage structure relative to other points across the stressor gradient, to inform instream nutrient and sediment objectives. Identification and comparison of thresholds for macroinvertebrate, periphyton, and bacterial assemblages aimed at making the setting of objectives more robust and may further provide a better understanding of the underlying mechanisms of nutrient and fine sediment effects. Gradient forest, a novel approach to assemblage threshold identification based on regression‐tree‐based random forest models for individual taxa, allowed inclusion of multiple predictors to strengthen the evidence of cause and effect between stressors and multispecies responses. The most prominent macroinvertebrate and periphyton assemblage threshold across the nitrogen (N) gradient was located at very low levels and mainly attributed to declines of multiple taxa. This provided strong evidence for stream assemblages being significantly affected when N concentrations exceed reference conditions and for effects cascading through the ecosystem. The most prominent macroinvertebrate assemblage threshold across a gradient of suspended fine sediment was also located at very low levels and attributed to declines of multiple taxa. However, this threshold did not correspond with periphyton assemblage thresholds, suggesting that the sensitivity of macroinvertebrate assemblages is unrelated to sediment effects on periphyton assemblages. Overall, the spectrum of N concentrations and fine sediment levels within which these stream assemblages changed most dramatically were relatively narrow given the wide gradients tested. We conclude that assemblage thresholds can inform the setting of generic instream nutrient and sediment objectives for stream ecosystem health. For example, the most stringent objective for instream N concentration should be set at values similar to reference concentrations for full protection of sensitive taxa or overall stream biodiversity. To avoid severe degradation of stream biodiversity, the least stringent N objective should stay well below the point where significant turnover subsided.
Comparative analyses of flower scent inSileneaereveal a contrasting phylogenetic signal between night and day emissions
Authors: Prieto‐Benítez Samuel , Millanes Ana M. , Dötterl Stefan , Giménez‐Benavides Luis 
Published: October 2016

AbstractFlower scents are complex blends of volatile compounds often shaped by selection pressures exerted by mutualistic and antagonistic interaction partners, but also by phylogenetic constraints. So far, little is known about the relative effect of selection and phylogenetic signal on scent patterns, and no study to date analyzed the phylogenetic signal in multivariate semiquantitative scent patterns. We analyzed the phylogenetic signal in qualitative and semi‐quantitative patterns of flower scents in 47 Sileneae (Caryophyllaceae) species using phylogenetic principal component analysis (pPCA) and several indices of univariate and multivariate phylogenetic signal. As previous results showed that Sileneae species are visited by diurnal and nocturnal pollinators and flower scents also vary along the day, we compared the phylogenetic signal between night and day. MultivariatepPCAanalyses identified compounds that correlate with the phylogeny at both night and day; however, multivariate Bloomberg′s K detected phylogenetic signal in the dataset of night scents, but not of day scents. In multivariate qualitative datasets, phylogenetic signal was neither found for day nor for night scents. In univariate analyses, phylogenetic signal was detected for some compounds both for day and night scents. Overall, we found that the phylogenetic signal is stronger in night compared to day scents, which might be owed to the different guilds of pollinators at day and night. At day, the phylogenetic resemblance of Sileneae scents might be masked by or disappear due to divergent selective pressures exerted by a diverse guild of pollinators on the different species. In contrast, we hypothesize that the nocturnal moth pollinators exert similar selective pressures; thus, the phylogenetic similarity of scent profiles might be conserved. Future studies of scent phylogenetic signal must consider not only the usage of qualitative measures but also semiquantitative analyses.
Multiple transisthmian divergences, extensive cryptic diversity, occasional long‐distance dispersal, and biogeographic patterns in a marine coastal isopod with an amphi‐American distribution
Authors: Hurtado Luis A. , Mateos Mariana , Mattos Gustavo , Liu Shuang , Haye Pilar A. , Paiva Paulo C. 
Published: October 2016

AbstractExcirolana braziliensis is a coastal intertidal isopod with a broad distribution spanning the Atlantic and Pacific tropical and temperate coasts of the American continent. Two separate regional studies (one in Panama and one in Chile) revealed the presence of highly genetically divergent lineages, implying that this taxon constitutes a cryptic species complex. The relationships among the lineages found in these two different regions and in the rest of the distribution, however, remain unknown. To better understand the phylogeographic patterns of E. braziliensis, we conducted phylogenetic analyses of specimens from much of its entire range. We obtained DNA sequences for fragments of four mitochondrial genes (16S rDNA, 12S rDNA, COI, and Cytb) and also used publicly available sequences. We conducted maximum likelihood and Bayesian phylogenetic reconstruction methods. Phylogeographic patterns revealed the following: (1) new highly divergent lineages of E. braziliensis; (2) three instances of Atlantic–Pacific divergences, some of which appear to predate the closure of the Isthmus of Panama; (3) the distributional limit of highly divergent lineages found in Brazil coincides with the boundary between two major marine coastal provinces; (4) evidence of recent long‐distance dispersal in the Caribbean; and (5) populations in the Gulf of California have closer affinities with lineages further south in the Pacific, which contrasts with the closer affinity with the Caribbean reported for other intertidal organisms. The high levels of cryptic diversity detected also bring about challenges for the conservation of this isopod and its fragile environment, the sandy shores. Our findings underscore the importance of comprehensive geographic sampling for phylogeographic and taxonomical studies of broadly distributed putative species harboring extensive cryptic diversity.
Glacial refugia and postglacial expansion of the alpine–prealpine plant species Polygala chamaebuxus
Authors: Windmaißer Tobias , Kattari Stefan , Heubl Günther , Reisch Christoph 
Published: October 2016

AbstractThe shrubby milkwort (Polygala chamaebuxus L.) is widely distributed in the Alps, but occurs also in the lower mountain ranges of Central Europe such as the Franconian Jura or the Bohemian uplands. Populations in these regions may either originate from glacial survival or from postglacial recolonization. In this study, we analyzed 30 populations of P. chamaebuxus from the whole distribution range using AFLP (Amplified Fragment Length Polymorphism) analysis to identify glacial refugia and to illuminate the origin of P. chamaebuxus in the lower mountain ranges of Central Europe. Genetic variation and the number of rare fragments within populations were highest in populations from the central part of the distribution range, especially in the Southern Alps (from the Tessin Alps and the Prealps of Lugano to the Triglav Massiv) and in the middle part of the northern Alps. These regions may have served, in accordance with previous studies, as long‐term refugia for the glacial survival of the species. The geographic pattern of genetic variation, as revealed by analysis of molecular variance, Bayesian cluster analysis and a PopGraph genetic network was, however, only weak. Instead of postglacial recolonization from only few long‐term refugia, which would have resulted in deeper genetic splits within the data set, broad waves of postglacial expansion from several short‐term isolated populations in the center to the actual periphery of the distribution range seem to be the scenario explaining the observed pattern of genetic variation most likely. The populations from the lower mountain ranges in Central Europe were more closely related to the populations from the southwestern and northern than from the nearby eastern Alps. Although glacial survival in the Bohemian uplands cannot fully be excluded, P. chamaebuxus seems to have immigrated postglacially from the southwestern or central‐northern parts of the Alps into these regions during the expansion of the pine forests in the early Holocene.
Both natural selection and isolation by distance explain phenotypic divergence in bill size and body mass between South Australian little penguin colonies
Authors: Colombelli‐Négrel Diane 
Published: October 2016

AbstractMorphological variation between populations of the same species can arise as a response to genetic variation, local environmental conditions, or a combination of both. In this study, I examined small‐scale geographic variation in bill size and body mass in little penguins (Eudyptula minor) across five breeding colonies in South Australia separated by <150 km. To help understand patterns driving the differences, I investigated these variations in relation to environmental parameters (air temperature, sea surface temperature, and water depth) and geographic distances between the colonies. I found substantial morphological variation among the colonies for body mass and bill measurements (except bill length). Colonies further located from each other showed greater morphological divergence overall than adjacent colonies. In addition, phenotypic traits were somewhat correlated to environmental parameters. Birds at colonies surrounded by hotter sea surface temperatures were heavier with longer and larger bills. Birds with larger and longer bills were also found at colonies surrounded by shallower waters. Overall, the results suggest that both environmental factors (natural selection) and interpopulation distances (isolation by distance) are causes of phenotypic differentiation between South Australian little penguin colonies.
Population genetic structure, differentiation, and diversity in Tetrix subulata pygmy grasshoppers: roles of population size and immigration
Authors: Tinnert Jon , Hellgren Olof , Lindberg Jenny , Koch‐Schmidt Per , Forsman Anders 
Published: October 2016

AbstractGenetic diversity within and among populations and species is influenced by complex demographic and evolutionary processes. Despite extensive research, there is no consensus regarding how landscape structure, spatial distribution, gene flow, and population dynamics impact genetic composition of natural populations. Here, we used amplified fragment length polymorphisms (AFLPs) to investigate effects of population size, geographic isolation, immigration, and gene flow on genetic structure, divergence, and diversity in populations of Tetrix subulata pygmy grasshoppers (Orthoptera: Tetrigidae) from 20 sampling locations in southern Sweden. Analyses of 1564 AFLP markers revealed low to moderate levels of genetic diversity (PPL = 59.5–90.1; Hj = 0.23–0.32) within and significant divergence among sampling localities. This suggests that evolution of functional traits in response to divergent selection is possible and that gene flow is restricted. Genetic diversity increased with population size and with increasing proportion of long‐winged phenotypes (a proxy of recent immigration) across populations on the island of Öland, but not on the mainland. Our data further suggested that the open water separating Öland from the mainland acts as a dispersal barrier that restricts migration and leads to genetic divergence among regions. Isolation by distance was evident for short interpopulation distances on the mainland, but gradually disappeared as populations separated by longer distances were included. Results illustrate that integrating ecological and molecular data is key to identifying drivers of population genetic structure in natural populations. Our findings also underscore the importance of landscape structure and spatial sampling scheme for conclusions regarding the role of gene flow and isolation by distance.
Quantifying mortality of modular organisms: a comparison of partial and whole‐colony mortality in a colonial bryozoan
Authors: Denley Danielle , Metaxas Anna 
Published: October 2016

AbstractComprehensive studies on the population dynamics of colonial organisms require estimates of mortality from the level of the individual module (partial mortality) to the entire colony (whole‐colony mortality), as well as determining the factors that affect mortality at each level of organization. However, accurate measurements of whole‐colony and partial mortality of modular organisms can be difficult to obtain, and few studies involve concurrent measurements of modular and colony mortality. We implemented multiple approaches to measure whole‐colony and partial mortality of modular species using the colonial bryozoan Membranipora membranacea as a model organism. M. membranacea is a cosmopolitan species and of particular ecological significance in the northwest Atlantic, where it is the dominant epiphyte on laminarian kelps and the main driver for the defoliation of kelp beds. Rates of whole‐colony mortality were measured in the field (1) indirectly through repeated subsampling cohort analyses and (2) directly by tagging colonies in situ. Partial mortality of colonies was measured (1) in the field by quantifying the proportion of degenerated zooids per colony and (2) in the laboratory by monitoring loss of colony surface area during seasonal senescence of colonies over winter. Temporal patterns differed substantially between partial and whole‐colony mortality, suggesting that factors affecting mortality of individual modules differ from those affecting whole colonies. Our study indicated that the accuracy of common methods for measuring mortality of modular organisms depends on the species‐specific life‐history characteristics. However, we suggest that rates and mechanisms of whole‐colony and partial mortality can be most accurately quantified by revisiting tagged individuals in situ and recording loss of entire colonies (whole‐colony mortality) and loss of living colony area (partial mortality) between successive sampling times. For M. membranacea, measuring whole‐colony or partial mortality in isolation would overestimate important demographic rates and underestimate the influence of temperature on mortality, respectively. This study demonstrates the need to include mortality measurements from the level of the individual module to the entire colony when quantifying population dynamics of colonial organisms.
Predicting animal home‐range structure and transitions using a multistate Ornstein‐Uhlenbeck biased random walk
Authors: Breed Greg A. , Golson Emily A. , Tinker M. Tim 
Published: October 2016

AbstractThe home‐range concept is central in animal ecology and behavior, and numerous mechanistic models have been developed to understand home range formation and maintenance. These mechanistic models usually assume a single, contiguous home range. Here we describe and implement a simple home‐range model that can accommodate multiple home‐range centers, form complex shapes, allow discontinuities in use patterns, and infer how external and internal variables affect movement and use patterns. The model assumes individuals associate with two or more home‐range centers and move among them with some estimable probability. Movement in and around home‐range centers is governed by a two‐dimensional Ornstein‐Uhlenbeck process, while transitions between centers are modeled as a stochastic state‐switching process. We augmented this base model by introducing environmental and demographic covariates that modify transition probabilities between home‐range centers and can be estimated to provide insight into the movement process. We demonstrate the model using telemetry data from sea otters (Enhydra lutris) in California. The model was fit using a Bayesian Markov Chain Monte Carlo method, which estimated transition probabilities, as well as unique Ornstein‐Uhlenbeck diffusion and centralizing tendency parameters. Estimated parameters could then be used to simulate movement and space use that was virtually indistinguishable from real data. We used Deviance Information Criterion (DIC) scores to assess model fit and determined that both wind and reproductive status were predictive of transitions between home‐range centers. Females were less likely to move between home‐range centers on windy days, less likely to move between centers when tending pups, and much more likely to move between centers just after weaning a pup. These tendencies are predicted by theoretical movement rules but were not previously known and show that our model can extract meaningful behavioral insight from complex movement data.
Leveraging constraints and biotelemetry data to pinpoint repetitively used spatial features
Authors: Brost Brian M. , Hooten Mevin B. , Small Robert J. 
Published: October 2016

AbstractSatellite telemetry devices collect valuable information concerning the sites visited by animals, including the location of central places like dens, nests, rookeries, or haul‐outs. Existing methods for estimating the location of central places from telemetry data require user‐specified thresholds and ignore common nuances like measurement error. We present a fully model‐based approach for locating central places from telemetry data that accounts for multiple sources of uncertainty and uses all of the available locational data. Our general framework consists of an observation model to account for large telemetry measurement error and animal movement, and a highly flexible mixture model specified using a Dirichlet process to identify the location of central places. We also quantify temporal patterns in central place use by incorporating ancillary behavioral data into the model; however, our framework is also suitable when no such behavioral data exist. We apply the model to a simulated data set as proof of concept. We then illustrate our framework by analyzing an Argos satellite telemetry data set on harbor seals (Phoca vitulina) in the Gulf of Alaska, a species that exhibits fidelity to terrestrial haul‐out sites.
Demographical and clinicopathological characteristics in heart failure and outcome predictors: a prospective, observational study
Authors: Sajeev Chakanalil Govindan , Rajan Nair Shreetal , George Biju , Rajesh Gopalan Nair , Krishnan Mangalath Narayanan 
Published: October 2016

AbstractAimsThe aims of the study were to study the demographical and clinicopathological characteristics of patients presenting with heart failure and evaluate the 1 year outcomes and to identify risk predictors if any.Methods and resultsA prospective observational study was conducted in consecutive patients of systolic heart failure. The study was divided into two parts—an initial 6 month enrolment phase followed up for 1 year for major adverse cardiovascular events. All patients were treated according to the Institutional Heart Failure Protocol. Demographical and clinicopathophysiological characteristics were studied, and results were analysed. A total of 143 patients were enrolled. The mean age of subjects was 56.4 years with male subjects constituting almost two‐thirds of the study population. The commonest aetiology of heart failure was ischemic with valvular heart disease being the commonest cause of non‐ischemic heart failure. Bendopnea, a recently described symptom of heart failure, was found in a significant number of subjects. By univariate analysis, male sex (P = 0.042) and cardiomegaly (P = 0.035) were predictors of rehospitalization, whereas the univariate predictors of mortality were ischemic aetiology (P = 0.000), age > 50 years (P = 0.007), hypertension (P = 0.012), worsening NYHA class (P = 0.003), diabetes mellitus (P = 0.009), and hypokalaemia (P = 0.006). Multivariate analysis performed showed age > 50 years [P = 0.007; OR (CI) = 13.547 (2.034–90.238)], NYHA class [P = 0.002; OR (CI) = 32.300 (3.733–276.532)], and hypokalaemia [P = 0.031; OR (CI) = 7.524 (1.208–46.862)] as significant predictors of mortality during long‐term follow‐up.ConclusionsThe study will definitely help us to throw more light in identifying risk predictors of heart failure and help in improving clinical outcomes.