Publications by authors named "Dray S"

Interspecific interactions can influence species' activity and movement patterns. In particular, species may avoid or attract each other through reactive responses in space and/or time. However, data and methods to study such reactive interactions have remained scarce and were generally limited to two interacting species.

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In phylogenomics, incongruences between gene trees, resulting from both artifactual and biological reasons, can decrease the signal-to-noise ratio and complicate species tree inference. The amount of data handled today in classical phylogenomic analyses precludes manual error detection and removal. However, a simple and efficient way to automate the identification of outliers from a collection of gene trees is still missing.

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This paper studies the role of free media in how governments and the public responded to the COVID-19 pandemic. We first document the presence of policy and behavioural responsiveness during the early phase of the pandemic. Using a panel data of daily COVID-19 deaths, lockdown policies, and mobility changes in 155 countries, we find that governments were more likely to impose a lockdown, and citizens to reduce their mobility, as the initial number of deaths increased.

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Article Synopsis
  • The 'Global Spectrum of Plant Form and Function Dataset' includes mean values for six key vascular plant traits, essential for understanding plant variation.
  • This dataset aggregates around 1 million trait records from the TRY database and other sources, encompassing 92,159 species mean values across 46,047 species.
  • Comprehensive data quality management and validation ensure this is the largest and most reliable collection of empirical data on vascular plant traits available.
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Objectives: Mycobacterium tuberculosis (Mtb) infections result in a wide spectrum of clinical presentations but without proven Mtb genetic determinants. Herein, we hypothesized that the genetic features of Mtb clinical isolates, such as specific polymorphisms or microdiversity, may be linked to tuberculosis (TB) severity.

Methods: A total of 234 patients with pulmonary TB (including 193 drug-susceptible and 14 monoresistant cases diagnosed between 2017 and 2020 and 27 multidrug-resistant cases diagnosed between 2010 and 2020) were stratified according to TB disease severity, and Mtb genetic features were explored using whole genome sequencing, including heterologous single-nucleotide polymorphism (SNP), calling to explore microdiversity.

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We study changes in social distancing and government policy in response to local outbreaks during the COVID-19 pandemic. Using aggregated county-level data from approximately 20 million smartphones in the United States, we show that social distancing behaviors have responded to local outbreaks: a 1% increase in new cases (deaths) is associated with a 3% (11%) increase in social distancing intensity. Responsiveness is reinforced by the presence of public measures restricting movements, but remains significant in their absence.

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Article Synopsis
  • The mechanisms driving the variation in species richness across regions are not fully understood, but they may be tied to how resources limit the number of species in a given area.
  • Research indicates that the ecological factors influencing species richness could also create patterns in genetic diversity among populations.
  • A study on 38 mammal species in North America reveals that areas with high species richness often have lower genetic variation within species, suggesting a link between resource availability and both species and genetic diversity.
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Fisher's principle states that natural selection favours an equal number of male and female births at the population level, unless there are sex differences in rearing costs or sex differences in mortality before the end of the period of parental investment. Sex differences in rearing costs should be more pronounced in low- than in high-resource settings. We, therefore, examined whether human development index and sex differences in child mortality contribute to the natural variation in human sex ratio at birth across the globe.

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Objective: To develop a protocol for subconjunctival enucleation and orbital implant placement in standing horses and to document short- and long-term complications, cosmesis, and client satisfaction.

Animals: 20 horses with nonneoplastic ocular disease requiring enucleation.

Procedures: A standardized protocol of surgical suite cleaning, patient preparation, sedation, local nerve blocks, surgical procedure, and postoperative care was performed.

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Background: Appropriate hand hygiene (HH) is key to reducing healthcare-acquired infections. The World Health Organization (WHO) recommends education and training to improve HH knowledge and compliance. Physicians are ranked among the worst of all healthcare workers for compliant handrubbing with its origin probably being the failure to learn this essential behavior during undergraduate medical studies.

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In large mammal communities, little is known about modification of interspecific interactions through habitat structure changes. We assessed the effects of African elephants (Loxodonta africana) on features of woody habitat structure that can affect predator-prey interactions. We then explored how this can influence where African lions (Panthera leo) kill their prey.

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Microbial communities, which drive major ecosystem functions, consist of a wide range of interacting species. Understanding how microbial communities are structured and the processes underlying this is crucial to interpreting ecosystem responses to global change but is challenging as microbial interactions cannot usually be directly observed. Multiple efforts are currently focused to combine next-generation sequencing (NGS) techniques with refined statistical analysis (e.

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Many perennial plants display masting, that is, fruiting with strong interannual variations, irregular and synchronized between trees within the population. Here, we tested the hypothesis that the early flower phenology in temperate oak species promotes stochasticity into their fruiting dynamics, which could play a major role in tree reproductive success. From a large field monitoring network, we compared the pollen phenology between temperate and Mediterranean oak species.

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For many patients, notably among elderly nursing home residents, no plans about end-of-life decisions and palliative care are made. Consequently, when these patients experience life-threatening events, decisions to withhold or withdraw life-support raise major challenges for emergency healthcare professionals. Emergency department premises are not designed for providing the psychological and technical components of end-of-life care.

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Phenotypic plasticity may contribute to the invasive success of an alien species in a new environment. A highly plastic species may survive and reproduce in more diverse environments, thereby supporting establishment and colonization. We focused on plasticity in the circadian rhythm of activity, which can favour species coexistence in invasion, for the invasive species , which is expected to be a weaker direct competitor than other species of the resident community.

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Describing how ecological interactions change over space and time and how they are shaped by environmental conditions is crucial to understand and predict ecosystem trajectories. However, it requires having an appropriate framework to measure network diversity locally, regionally and between samples (α-, γ- and β-diversity). Here, we propose a unifying framework that builds on Hill numbers and accounts both for the probabilistic nature of biotic interactions and the abundances of species or groups.

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Endotracheal aspirate (ETA) surveillance cultures have been used to predict the microorganisms responsible for ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients for 3 decades. However, although more than a dozen studies have been performed, the usefulness and the safety of this strategy are still debated. Tracheobronchial bacterial colonization often precedes the occurrence of VAP, and it has been postulated that the microbes present in the tracheal secretions a few days before VAP might be the same as those retrieved in the lower respiratory tract.

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The fourth-corner analysis aims to quantify and test for relationships between species traits and site-specific environmental variables, mediated by site-specific species abundances. Since there is no common unit of observation, the significance of the relationships is tested using a double permutation procedure (site based and species based). This method implies that all species and sites are independent of each other.

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Eigenvector-mapping methods such as Moran's eigenvector maps (MEM) are derived from a spatial weighting matrix (SWM) that describes the relations among a set of sampled sites. The specification of the SWM is a crucial step, but the SWM is generally chosen arbitrarily, regardless of the sampling design characteristics. Here, we compare the statistical performances of different types of SWMs (distance-based or graph-based) in contrasted realistic simulation scenarios.

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Article Synopsis
  • The study discusses two main methods—direct gradient analysis and variation partitioning—that are used to assess how species distribution is influenced by environmental factors and species sorting within metacommunities.
  • It highlights the problem of spatial autocorrelation, where both species and environmental data are influenced by spatial processes, which can create false correlations and lead to high Type I error rates in variation partitioning.
  • The authors propose a new variation partitioning method that accounts for these spatial autocorrelations and demonstrate its effectiveness using simulated data and an empirical plant dataset, showing a significant reduction in spurious correlation influences.
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Species assemblages are the results of various processes, including dispersion and habitat filtering. Disentangling the effects of these different processes is challenging for statistical analysis, especially when biotic interactions should be considered. In this study, we used plants (producers) and leafhoppers (phytophagous) as model organisms, and we investigated the relative importance of abiotic versus biotic factors that shape community assemblages, and we infer on their biotic interactions by applying three-step statistical analysis.

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Statistical testing of trait-environment association from data is a challenge as there is no common unit of observation: the trait is observed on species, the environment on sites and the mediating abundance on species-site combinations. A number of correlation-based methods, such as the community weighted trait means method (CWM), the fourth-corner correlation method and the multivariate method RLQ, have been proposed to estimate such trait-environment associations. In these methods, valid statistical testing proceeds by performing two separate resampling tests, one site-based and the other species-based and by assessing significance by the largest of the two -values (the test).

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Animals may anticipate and try to avoid, at some costs, physical encounters with other competitors. This may ultimately impact their foraging distribution and intake rates. Such cryptic interference competition is difficult to measure in the field, and extremely little is known at the interspecific level.

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