39 research outputs found

    Habitat and community structure modulate fish interactions in a neotropical clearwater river

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    Species interactions can modulate the diversity and enhance the stability of biological communities in aquatic ecosystems. Despite previous efforts to describe fish interactions in tropical rivers, the role of habitat characteristics, community structure, and trophic traits over these interactions is still poorly understood. To investigate among-habitat variation in substratum feeding pressure and agonistic interactions between fishes, we used remote underwater videos in three habitats of a clearwater river in the Central Western, Brazil. We also performed visual surveys to estimate the abundance and biomass of fishes and proposed a trophic classification to understand how these variables can affect fish interactions. Community structure was the main factor affecting the variation in the interactions among the habitats. Biomass was the main variable determining which habitat a fish will feed on, while species abundance determined with how many other species it will interact in the agonistic interaction networks for each habitat. Specific habitats are not only occupied, but also used in distinct ways by the fish community. Overall, our results demonstrate the importance of the heterogeneity of habitats in tropical rivers for the interactions performed by the fishes and how the intensity of these interactions is affected by community structure

    Seascape configuration leads to spatially uneven delivery of parrotfish herbivory across a Western Indian Ocean seascape

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    Spatial configuration of habitat types in multihabitat seascapes influence ecological function through links of biotic and abiotic processes. These connections, for example export of organic matter or fishes as mobile links, define ecosystem functionality across broader spatial scales. Herbivory is an important ecological process linked to ecosystem resilience, but it is not clear how herbivory relates to seascape configuration. We studied how herbivory and bioerosion by 3 species of parrotfish were distributed in a multi-habitat tropical seascape in the Western Indian Ocean (WIO). We surveyed the abundance of three species with different life histories—Leptoscarus vaigiensis (seagrass species), Scarus ghobban (juvenile-seagrass/adults-reefs) and Scarus rubroviolaceus (reef species) —in seagrass meadows and on reefs and recorded their selectivity of feeding substrate in the two habitats. Herbivory rates for L. vaigiensis and S. ghobban and bioerosion for S. rubroviolaceus were then modelled using bite rates for different size classes and abundance and biomass data along seascape gradients (distance to alternative habitat types such as land, mangrove and seagrass). Bioerosion by S. rubroviolaceus was greatest on reefs far from seagrass meadows, while herbivory rates by S. ghobban on reefs displayed the opposite pattern. Herbivory in seagrass meadows was greatest in meadows close to shore, where L. vaigiensis targeted seagrass leaves and S. ghobban the epiphytes growing on them. Our study shows that ecological functions performed by fish are not equally distributed in the seascape and are influenced by fish life history and the spatial configuration of habitats in the seascape. This has implications for the resilience of the system, in terms of spatial heterogeneity of herbivory and bioerosion and should be considered in marine spatial planning and fisheries management

    Computational procedure to an accurate DFT simulation to solid state systems

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    The density functional theory has become increasingly common as a methodology to explain the properties of crystalline materials because of the improvement in computational infrastructure and software development to perform such computational simulations. Although several studies have shown that the characteristics of certain classes of materials can be represented with great precision, it is still necessary to improve the methods and strategies in order to achieve more realistic computational modeling. In the present work, strategies are reported in a systematic way for the accurate representation of crystalline systems. The crystalline compound chosen for the study as a case test was BaMoO4, both because of its potential technological application and because of the low accuracy of the simulations previously reported in the literature. The computational models were carried out with the B3LYP and WC1LYP functionals selected from an initial set containing eight hybrid functionals in conjunction with an all-electron basis set. Two different strategies were applied for improving the description of the initial models, both involving atomic basis set optimization and Hartree-Fock exchange percentage adjustment. The results obtained with the two strategies show a precision of structural parameters, band gap energy, and vibrational properties never before presented in theoretical studies of BaMoO4. Finally, a flowchart of good calculation practices is elaborated. This can be of great value for the organization and conduction of calculations in new research

    AI is a viable alternative to high throughput screening: a 318-target study

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    : High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    A História da Alimentação: balizas historiográficas

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    Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

    Search for pair production of excited top quarks in the lepton+jets final state

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    Role of Special Schools in promoting inclusive Education

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    World of education for disable children is constantly changing. Special schools have to change according to the demand of its clients or the environmental factors. Inclusion is seen as a right and inclusive education has become a compulsion in the field of special education. Irrespective of disability, a child with disability has the same rights to education as any other child in his/her age. Many declarations, decades and policy papers have fueled this drive world over and have been showing the direction for policy makers and practitioners. This study explores and highlights the importance of inclusive education and role of special schools in promoting it. The research focus has been to investigate various roles for special schools, so that they can meet some of the challenges of inclusive education. The purpose of the research was for me to develop an understanding and knowledge about this growing phenomenon of inclusive education, its challenges and how special schools can contribute to make it effective. The literature review examines theories and concepts of inclusive education and evolution of special education. It is mainly focused on Indian response to it inclusive education, effect of medical/social models on special education and international movement towards inclusive education with special..

    Locations of villages, MPAs, sample collections, and experiments.

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    <p>Ovals represent the area in which samples were collected for microsatellite analysis and where experiments involving caging of mature <i>S</i>. <i>polycystum</i> fronds and transplanting of recruit-sized ramets were conducted. Experiments caging recruit-sized ramets and transplanting adults were run slightly seaward. A portion of the figure modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155049#pone.0155049.ref026" target="_blank">26</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155049#pone.0155049.ref027" target="_blank">27</a>].</p

    Growth of mature, caged <i>S</i>. <i>polycystum</i> fronds from MPAs and non-MPAs when reciprocally transplanted p-values above the bars are from paired t-tests assessing the effects of origin.

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    <p>The boxed p-values are from Mann-Whitney U tests assessing the effect of habitat (placement within the MPA or non-MPA) on growth. N = 5 at each location; α = 0.025 to correct for multiple contrasts.</p
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