15 research outputs found

    Modelling the impact of school reopening and contact tracing strategies on Covid-19 dynamics in different epidemiologic settings in Brazil

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    We simulate the impact of school reopening during the COVID-19 pandemic in three major urban centers in Brazil to identify the epidemiological indicators and the best timing for the return of in-school activities and the effect of contact tracing as a mitigation measure. Our goal is to offer guidelines for evidence-based policymaking. We implement an extended SEIR model stratified by age and considering contact networks in different settings – school, home, work, and community, in which the infection transmission rate is affected by various intervention measures. After fitting epidemiological and demographic data, we simulate scenarios with increasing school transmission due to school reopening, and also estimate the number of hospitalization and deaths averted by the implementation of contact tracing. Reopening schools results in a non-linear increase in reported COVID-19 cases and deaths, which is highly dependent on infection and disease incidence at the time of reopening. When contact tracing and quarantining are restricted to school and home settings, a large number of daily tests is required to produce significant effects in reducing the total number of hospitalizations and deaths. Policymakers should carefully consider the epidemiological context and timing regarding the implementation of school closure and return of in-person school activities. While contact tracing strategies prevent new infections within school en- vironments, they alone are not sufficient to avoid significant impacts on community transmission

    Towards an applied metaecology

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    The complexity of ecological systems is a major challenge for practitioners and decision-makers who work to avoid, mitigate and manage environmental change. Here, we illustrate how metaecology - the study of spatial interdependencies among ecological systems through fluxes of organisms, energy, and matter - can enhance understanding and improve managing environmental change at multiple spatial scales. We present several case studies illustrating how the framework has leveraged decision-making in conservation, restoration and risk management. Nevertheless, an explicit incorporation of metaecology is still uncommon in the applied ecology literature, and in action guidelines addressing environmental change. This is unfortunate because the many facets of environmental change can be framed as modifying spatial context, connectedness and dominant regulating processes - the defining features of metaecological systems. Narrowing the gap between theory and practice will require incorporating system-specific realism in otherwise predominantly conceptual studies, as well as deliberately studying scenarios of environmental change. (C) 2019 Associacao Brasileira de Ciencia Ecologica e Conservacao. Published by Elsevier Editora Ltda.Peer reviewe

    The shared influence of phylogeny and ecology on the reproductive patterns of Myrteae (Myrtaceae)

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    1. Many factors shape plant reproductive patterns including climate, competition or attraction of pollinators and seed dispersers, flower and fruit morphologies and phylogenetic relationships. South American Myrtaceae (Myrteae) were chosen to evaluate hypotheses on how abiotic and biotic factors, morphology and phylogeny influence plant reproductive phenology.2. We examined whether Myrteae reproductive patterns are seasonal and related to climate; whether aggregated or segregated flowering and fruiting occur among species sharing pollinators or seed dispersers; the relationship between phenological and morphological traits, time of reproduction and Myrteae phylogenetic history; and the shared influence of ecological (environmental) and phylogenetic factors on Myrteae reproductive patterns.3. We observed flowering and fruiting of 34 Myrteae species during 30 months in an Atlantic rain forest (south-eastern Brazil). We employed circular statistics to test for seasonality and multiple regressions to relate climate and phenology. Competition and facilitation hypotheses were tested using null models. We quantified the phylogenetic signal on phenology and morphology of Myrteae species using phylogenetic eigenvector regression (PVR) analyses, and used PVR and partial regressions to quantify the influences of ecology and phylogeny on phenology.4. Myrteae flowered seasonally, whereas fruiting was not seasonal. Environmental factors (day-length and temperature) and associations with biotic vectors through facilitation hypothesis explained the aggregated blossom. Fruit maturation time affected the species' flowering sequence. Plants with longer fruit maturation times flowered at the end of the appropriate season, explaining the continuous fruit availability despite the seasonal flowering. The random fruiting pattern explained the regular presence of seed dispersers. Myrteae phenology was phylogenetically structured, even when phenophases were not seasonal, i.e., closer related species fruited under more similar environmental conditions, suggesting that the reproductive phenological niche was inherited along the course of evolution. We detected a shared influence of ecology and phylogeny on Myrteae phenological responses, and the ecological component explained better phenological variation than phylogeny.5. Synthesis. We provided a new perspective on plant phenology based on phylogeny and ecology and demonstrated the importance of considering their shared influence in phenological studies. Our analyses can be employed for the most representative families of highly diverse ecosystems to improve our understanding of evolutionary patterns and general trends in phenology.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Ecological drivers of plant genetic diversity at the southern edge of geographical distributions: forestal vines in a temperate region

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    The Tropical Niche Conservatism hypothesis is one of the most relevant theories to explain why tropical diversity is high, although the mechanisms underlying this hypothesis require further clarification. A possible research avenue to address the underlying mechanisms includes determining population-level processes associated with such a hypothesis, in particular by trying to identify how adaptation may occur in extreme niche conditions at the edges of species ranges. However, the determinants of molecular diversity at the edges of geographical distributions of tropical taxa are still poorly known. Here we assessed which environmental variables determine diversity in nuclear and plastid genetic markers for populations of four Passiflora species in the southern limit of their geographical distributions. Climatic factors can drive genetic diversity, and their importance varies according to the marker. The primary predictors are variables representing higher temperatures during cold periods of the year and higher precipitation during dry periods. We concluded that, although these species are present in colder areas at the edge of their range, Tropical Niche Conservatism acts as a restraining force on genetic diversity in southern populations of Passiflora

    Appendix A. A table reporting phylogenetic statistics for clades representing mammal families included in Fig. 2., figures showing variation in size ratios (VSR) with tree stemminess and under an Ornstein–Uhlenbeck process, and a figure depicting the phylogeny for the mammal community of Yotvata, Israel.

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    A table reporting phylogenetic statistics for clades representing mammal families included in Fig. 2., figures showing variation in size ratios (VSR) with tree stemminess and under an Ornstein–Uhlenbeck process, and a figure depicting the phylogeny for the mammal community of Yotvata, Israel

    Climate history, human impacts and global body size of Carnivora (Mammalia: Eutheria) at multiple evolutionary scales

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    Aim One of the longest recognized patterns in macroecology, Bergmann's rule, describes the tendency for homeothermic animals to have larger body sizes in cooler climates than their phylogenetic relatives in warmer climates. Here we provide an integrativ
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