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Showing papers by "Universidade Federal de Mato Grosso published in 2020"


Journal ArticleDOI
24 Apr 2020
TL;DR: The preliminary findings of this study suggest that the higher CQ dosage should not be recommended for critically ill patients with COVID-19 because of its potential safety hazards, especially when taken concurrently with azithromycin and oseltamivir.
Abstract: Importance There is no specific antiviral therapy recommended for coronavirus disease 2019 (COVID-19). In vitro studies indicate that the antiviral effect of chloroquine diphosphate (CQ) requires a high concentration of the drug. Objective To evaluate the safety and efficacy of 2 CQ dosages in patients with severe COVID-19. Design, Setting, and Participants This parallel, double-masked, randomized, phase IIb clinical trial with 81 adult patients who were hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was conducted from March 23 to April 5, 2020, at a tertiary care facility in Manaus, Brazilian Amazon. Interventions Patients were allocated to receive high-dosage CQ (ie, 600 mg CQ twice daily for 10 days) or low-dosage CQ (ie, 450 mg twice daily on day 1 and once daily for 4 days). Main Outcomes and Measures Primary outcome was reduction in lethality by at least 50% in the high-dosage group compared with the low-dosage group. Data presented here refer primarily to safety and lethality outcomes during treatment on day 13. Secondary end points included participant clinical status, laboratory examinations, and electrocardiogram results. Outcomes will be presented to day 28. Viral respiratory secretion RNA detection was performed on days 0 and 4. Results Out of a predefined sample size of 440 patients, 81 were enrolled (41 [50.6%] to high-dosage group and 40 [49.4%] to low-dosage group). Enrolled patients had a mean (SD) age of 51.1 (13.9) years, and most (60 [75.3%]) were men. Older age (mean [SD] age, 54.7 [13.7] years vs 47.4 [13.3] years) and more heart disease (5 of 28 [17.9%] vs 0) were seen in the high-dose group. Viral RNA was detected in 31 of 40 (77.5%) and 31 of 41 (75.6%) patients in the low-dosage and high-dosage groups, respectively. Lethality until day 13 was 39.0% in the high-dosage group (16 of 41) and 15.0% in the low-dosage group (6 of 40). The high-dosage group presented more instance of QTc interval greater than 500 milliseconds (7 of 37 [18.9%]) compared with the low-dosage group (4 of 36 [11.1%]). Respiratory secretion at day 4 was negative in only 6 of 27 patients (22.2%). Conclusions and Relevance The preliminary findings of this study suggest that the higher CQ dosage should not be recommended for critically ill patients with COVID-19 because of its potential safety hazards, especially when taken concurrently with azithromycin and oseltamivir. These findings cannot be extrapolated to patients with nonsevere COVID-19. Trial Registration ClinicalTrials.gov Identifier:NCT04323527

852 citations


Posted ContentDOI
11 Apr 2020-medRxiv
TL;DR: Preliminary findings suggest that the higher CQ dosage (10-day regimen) should not be recommended for COVID-19 treatment because of its potential safety hazards.
Abstract: This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

165 citations


Journal ArticleDOI
TL;DR: The habitat amount hypothesis predicts that species richness in plots of fixed size is more strongly and positively related to the amount of habitat around the plot than to patch size or isolation, and habitat amount better predicts species density than patch size and isolation combined.
Abstract: Decades of research suggest that species richness depends on spatial characteristics of habitat patches, especially their size and isolation. In contrast, the habitat amount hypothesis predicts that (1) species richness in plots of fixed size (species density) is more strongly and positively related to the amount of habitat around the plot than to patch size or isolation; (2) habitat amount better predicts species density than patch size and isolation combined, (3) there is no effect of habitat fragmentation per se on species density and (4) patch size and isolation effects do not become stronger with declining habitat amount. Data on eight taxonomic groups from 35 studies around the world support these predictions. Conserving species density requires minimising habitat loss, irrespective of the configuration of the patches in which that habitat is contained.

114 citations


Journal ArticleDOI
TL;DR: R/S seem to have an important role on the relief of suffering, having an influence on health outcomes and minimizing the consequences of social isolation, and the importance of public health measures that ensure the continuity of R/S activities during the pandemic is highlighted.
Abstract: Background:Evidence shows that religiosity and spirituality (R/S) are highly used in critical moments of life and that these beliefs are associated with clinical outcomes. However, further studies ...

103 citations


Journal ArticleDOI
TL;DR: It is demonstrated that the ranking-based approach to potentialize the RF method for maize yield prediction reduces the number of VIs needed to determine a high accuracy and relative low MAE, and the approach may contribute to decision-making actions, resulting in accurate management of maize fields.

101 citations


Journal ArticleDOI
TL;DR: In this article, the authors estimated thresholds of native vegetation loss in which there are abrupt changes in the occurrence and abundance of freshwater bioindicators and tested whether there are congruent responses among different biomes, biological groups and buffer sizes.
Abstract: Protecting riparian vegetation around streams is vital in reducing the detrimental effects of environmental change on freshwater ecosystems and in maintaining aquatic biodiversity. Thus, identifying ecological thresholds is useful for defining regulatory limits and for guiding the management of riparian zones towards the conservation of freshwater biota. Using nationwide data on fish and invertebrates occurring in small Brazilian streams, we estimated thresholds of native vegetation loss in which there are abrupt changes in the occurrence and abundance of freshwater bioindicators and tested whether there are congruent responses among different biomes, biological groups and riparian buffer sizes. Mean thresholds of native vegetation cover loss varied widely among biomes, buffer sizes and biological groups: ranging from 0.5% to 77.4% for fish, from 2.9% to 37.0% for aquatic invertebrates and from 3.8% to 43.2% for a subset of aquatic invertebrates. Confidence intervals for thresholds were wide, but the minimum values of these intervals were lower for the smaller riparian buffers (50 and 100 m) than larger ones (200 and 500 m), indicating that land use should be kept away from the streams. Also, thresholds occurred at a lower percentage of riparian vegetation loss in the smaller buffers, and were critically lower for invertebrates: reducing only 6.5% of native vegetation cover within a 50-m riparian buffer is enough to cross thresholds for invertebrates. Synthesis and applications. The high variability in biodiversity responses to loss of native riparian vegetation suggests caution in the use of a single riparian width for conservation actions or policy definitions nationwide. The most sensitive bioindicators can be used as early warning signals of abrupt changes in freshwater biodiversity. In practice, maintaining at least 50-m wide riparian reserves on each side of streams would be more effective to protect freshwater biodiversity in Brazil. However, incentives and conservation strategies to protect even wider riparian reserves (~100 m) and also taking into consideration the regional context will promote a greater benefit. This information should be used to set conservation goals and to create complementary mechanisms and policies to protect wider riparian reserves than those currently required by the federal law.

91 citations


Journal ArticleDOI
TL;DR: The higher the prevalence of comorbidities the higher the odds that the COVID-19 patient will need intensive care or will die, especially if the pre-existing disease is hypertension, heart disease, or diabetes.
Abstract: The new coronavirus, COVID-19 was declared a pandemic by the World Health Organization on March 11, 2020 Risk factors associated with this disease are age, sex, and the presence of comorbidities, the most common being hypertension, diabetes, and heart disease The aim of this meta-analysis was to calculate the prevalence and geographical distribution of comorbidities in all patients admitted to intensive care units (ICUs), and the mortality rate of COVID-19 We selected studies based upon epidemiological and clinical descriptions of the patients and mortality from the disease to determine the pooled prevalence of comorbidities in all patients and in mortality cases due to COVID-19 The pooled prevalence was estimated using the random effects model, and odds ratios were used to measure the probability of death for a patient with a comorbidity The total prevalence of comorbidities in patients with COVID-19 was 42% (95% CI: 25-60), 61% (95% CI: 42-80) in those admitted to the ICU, and 77% (95% CI: 68-86) among death cases; males were the most affected Hypertension was the most prevalent comorbidity in all three groups studied, accounting for 32%, 26%, and 35%, respectively The odds ratio of death for a patient with a comorbidity compared to one with no comorbidity was 24 (P < 00001) The higher the prevalence of comorbidities the higher the odds that the COVID-19 patient will need intensive care or will die, especially if the pre-existing disease is hypertension, heart disease, or diabetes

89 citations


Journal ArticleDOI
TL;DR: This database, including 2,406 validated freshwater native fish species, 232,936 georeferenced records, results from an extensive survey of species distribution including 590 different sources, represents a highly valuable source of information for further studies on freshwater fish biodiversity, biogeography and conservation.
Abstract: The Amazon Basin is an unquestionable biodiversity hotspot, containing the highest freshwater biodiversity on earth and facing off a recent increase in anthropogenic threats. The current knowledge on the spatial distribution of the freshwater fish species is greatly deficient in this basin, preventing a comprehensive understanding of this hyper-diverse ecosystem as a whole. Filling this gap was the priority of a transnational collaborative project, i.e. the AmazonFish project - https://www.amazon-fish.com/. Relying on the outputs of this project, we provide the most complete fish species distribution records covering the whole Amazon drainage. The database, including 2,406 validated freshwater native fish species, 232,936 georeferenced records, results from an extensive survey of species distribution including 590 different sources (e.g. published articles, grey literature, online biodiversity databases and scientific collections from museums and universities worldwide) and field expeditions conducted during the project. This database, delivered at both georeferenced localities (21,500 localities) and sub-drainages grains (144 units), represents a highly valuable source of information for further studies on freshwater fish biodiversity, biogeography and conservation.

82 citations


Posted Content
TL;DR: A systematic review of the literature aims to identify the state of the art of the use of convolutional neural networks in the process of identification and classification of plant diseases, delimiting trends, and indicating gaps.
Abstract: Plant diseases are considered one of the main factors influencing food production and minimize losses in production, and it is essential that crop diseases have fast detection and recognition. The recent expansion of deep learning methods has found its application in plant disease detection, offering a robust tool with highly accurate results. In this context, this work presents a systematic review of the literature that aims to identify the state of the art of the use of convolutional neural networks(CNN) in the process of identification and classification of plant diseases, delimiting trends, and indicating gaps. In this sense, we present 121 papers selected in the last ten years with different approaches to treat aspects related to disease detection, characteristics of the data set, the crops and pathogens investigated. From the results of the systematic review, it is possible to understand the innovative trends regarding the use of CNNs in the identification of plant diseases and to identify the gaps that need the attention of the research community.

71 citations


Journal ArticleDOI
TL;DR: It is shown that platelets boost the inflammasome capacity of human macrophages and neutrophils and are critical for IL-1 production by monocytes and an enriched platelet gene signature among the highest-expressed transcripts in IL- 1β-driven autoinflammatory diseases is revealed.

71 citations


Journal ArticleDOI
Thomas Püttker1, Renato Crouzeilles2, Mauricio Almeida-Gomes, Marina Schmoeller3, Daniel Maurenza3, Helena Alves-Pinto3, Helena Alves-Pinto2, Renata Pardini4, Marcus Vinícius Vieira3, Cristina Banks-Leite5, Carlos Fonseca6, Jean Paul Metzger4, Gustavo M. Accacio1, Gustavo M. Accacio4, Eduardo Roberto Alexandrino7, Camila dos Santos de Barros3, Juliano André Bogoni8, Danilo Boscolo9, Pedro H. S. Brancalion7, Adriana A. Bueno4, Elaine Cristina Barbosa Cambui10, Gustavo Rodrigues Canale11, Rui Cerqueira3, Ricardo Gomes César7, Gabriel Dalla Colletta12, Ana Cláudia Delciellos13, Marianna Dixo4, Candelaria Estavillo10, Carolina Franco Esteves, Fábio Falcão10, Fabiano Turini Farah7, Deborah Faria14, Katia Maria Paschoaletto Micchi de Barros Ferraz7, Silvio Frosini de Barros Ferraz7, Patrícia Alves Ferreira15, Maurício Eduardo Graipel8, Carlos E. V. Grelle3, Malva Isabel Medina Hernández8, Natália Macedo Ivanauskas, Rudi Ricardo Laps, Inara R. Leal16, Marília Mascarenhas Lima17, Marília Bruzzi Lion6, Marcelo Magioli7, Luiz Fernando Silva Magnago, Julia R.A.S. Mangueira7, Euvaldo Marciano-Jr14, Eduardo Mariano-Neto10, Márcia C. M. Marques18, Sebastião Venâncio Martins19, Marlla A. Matos10, Fabio Antônio Ribeiro Matos20, Jeanette I. Miachir, José M. Morante-Filho14, José M. Morante-Filho21, Natalie Olifiers22, Luiz Gustavo R. Oliveira-Santos, Mateus Luís Barradas Paciencia, Adriano Pereira Paglia23, Marcelo Passamani24, Carlos A. Peres25, Clarissa Machado Pinto Leite10, Tiago Jordão Porto10, Luciano Carramaschi de Alagão Querido24, Luciana Carvalho dos Reis16, Andréia Alves Rezende26, Dary Moreira Gonçalves Rigueira10, Pedro Luís Bernardo da Rocha10, Larissa Rocha-Santos14, Ricardo Ribeiro Rodrigues7, Rafael Alves dos Santos e Santos10, Juliana Silveira dos Santos27, Maxwell Souza Silveira28, Marcelo Simonelli, Marcelo Tabarelli16, Rodrigo Nogueira de Vasconcelos21, Blandina Felipe Viana10, Emerson M. Vieira29, Jayme Augusto Prevedello13 
TL;DR: It is argued that dismissing habitat fragmentation as a powerful force driving species extinction in tropical forest landscapes is premature and unsafe.

Journal ArticleDOI
TL;DR: The resistance mechanisms of mercury volatilization and bioaccumulation in plant tissues mediated by these endophytic fungi can contribute to bioremediation programs and need to be elucidated in the future.

Journal ArticleDOI
TL;DR: In this paper, the equivalence of quasinormal modes and geodesic quantities was investigated using the WKB method, and an analytical relation between the real part of quasiannormal frequencies at the eikonal limit and black hole shadow radius was found.

Journal ArticleDOI
TL;DR: An overview of recurrent morphological changes at macroscopic and histological levels seen in the placenta from gestational diabetes in humans and animal models is given.

Journal ArticleDOI
TL;DR: It is concluded that a positive polymerase chain reaction retest could be due to several reasons and should not always be considered as reinfection or reactivation of the disease.
Abstract: Background There is recently a concern regarding the reinfection and reactivation of previously reCoVered coronavirus disease 2019 (CoVID-19) patients. Aim To summarize the recent findings and reports of CoVID-19 reinfection in patients previously reCoVered from the disease. Methods This study was a systematic review of current evidence conducted in August 2020. The authors studied the probable reinfection risk of novel coronavirus (CoVID-19). We performed a systematic search using the keywords in online databases. The investigation adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist to ensure the reliability and validity of this study and results. Results We reviewed 31 studies. Eight studies described reCoVered patients with reinfection. Only one study reported reinfected patients who died. In 26 studies, there was no information about the status of the patients. Several studies indicated that reinfection is not probable and that post-infection immunity is at least temporary and short. Conclusion Based on our review, we concluded that a positive polymerase chain reaction retest could be due to several reasons and should not always be considered as reinfection or reactivation of the disease. Most relevant studies in positive retest patients have shown relative and probably temporary immunity after the reCoVery of the disease.

Journal ArticleDOI
TL;DR: The results show that integrating host traits, host ancestry, bioclimatic data, and microhabitat characteristics that are important for vector reproduction are imperative to understand and predict infection prevalence and diversity of vector-transmitted parasites.
Abstract: Geographic variation in environmental conditions as well as host traits that promote parasite transmission may impact infection rates and community assembly of vector-transmitted parasites. Identifying the ecological, environmental and historical determinants of parasite distributions and diversity is therefore necessary to understand disease outbreaks under changing environments. Here, we identified the predictors and contributions of infection probability and phylogenetic diversity of Leucocytozoon (an avian blood parasite) at site and species levels across the New World. To explore spatial patterns in infection probability and lineage diversity for Leucocytozoon parasites, we surveyed 69 bird communities from Alaska to Patagonia. Using phylogenetic Bayesian hierarchical models and high-resolution satellite remote-sensing data, we determined the relative influence of climate, landscape, geography and host phylogeny on regional parasite community assembly. Infection rates and parasite diversity exhibited considerable variation across regions in the Americas. In opposition to the latitudinal gradient hypothesis, both the diversity and prevalence of Leucocytozoon parasites decreased towards the equator. Host relatedness and traits known to promote vector exposure neither predicted infection probability nor parasite diversity. Instead, the probability of a bird being infected with Leucocytozoon increased with increasing vegetation cover (NDVI) and moisture levels (NDWI), whereas the diversity of parasite lineages decreased with increasing NDVI. Infection rates and parasite diversity also tended to be higher in cooler regions and higher latitudes. Whereas temperature partially constrains Leucocytozoon diversity and infection rates, landscape features, such as vegetation cover and water body availability, play a significant role in modulating the probability of a bird being infected. This suggests that, for Leucocytozoon, the barriers to host shifting and parasite host range expansion are jointly determined by environmental filtering and landscape, but not by host phylogeny. Our results show that integrating host traits, host ancestry, bioclimatic data and microhabitat characteristics that are important for vector reproduction are imperative to understand and predict infection prevalence and diversity of vector-transmitted parasites. Unlike other vector-transmitted diseases, our results show that Leucocytozoon diversity and prevalence will likely decrease with warming temperatures.

Journal ArticleDOI
TL;DR: By averaging several methods to estimate total richness, this work confirms that over 15,000 tree species are expected to occur in Amazonia and shows that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity.
Abstract: Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come

Journal ArticleDOI
07 Jan 2020-PLOS ONE
TL;DR: The results from the present study provide solid evidence that can be used at different decision-making levels for identifying the most appropriate management practices and effectively achieving sustainability of the anthropic activity occurring in the Pantanal.
Abstract: Climate change poses a critical threat to the Pantanal, the largest wetland in the world. Models indicate an increase in the frequency of extreme precipitation events and extended periods of drought. These changes can amplify consequences for Pantanal's ecological functioning, which has already experienced intensive human modification of its hydrological system and environmental health. The present study analyzed the spatial and temporal dynamics of rainfall and resulting extremes in the Brazilian area of the Upper Paraguay River Basin (UPRB) along with a co-evaluation of the global Sea Surface Temperature data (SST). The predicted results indicate that wet extreme precipitation events will become more frequent in the highlands, while severe and prolonged droughts triggered by warming SSTs in the Northern Hemisphere (North Atlantic and North Pacific oceans) will affect the Pantanal. The linear relations between precipitation with SST of very specific oceanic regions and even from specific oceanic indexes obtained in the present study significantly improve the forecasting capacity, mainly from a resulting reduction to two months of the lead-time between SST warming to concomitant precipitation impacts, and by explaining 80% of Pantanal´s precipitation variation from major oceanic indexes (e.g., ENSO, PDO, NAO, ATL3). Current SST trends will result in inter- and intra-annual flooding dynamic alterations, drastically affecting the Pantanal ecosystem functioning, with consequences for wildlife diversity and distribution. Regarding the foreseeable global climate and land use change scenarios, the results from the present study provide solid evidence that can be used at different decision-making levels (from local to global) for identifying the most appropriate management practices and effectively achieving sustainability of the anthropic activity occurring in the Pantanal.

Journal ArticleDOI
TL;DR: To reduce GHG emissions, Brazil will need to control deforestation induced by the expansion of the agricultural frontier in the Amazon and Cerrado biomes, which can only be achieved through significant political effort involving the government, entrepreneurs and society as a collective.
Abstract: Brazil is one of the world's biggest emitters of greenhouse gases (GHGs). Fire foci across the country contributes to these emissions and compromises emission reduction targets pledged by Brazil under the Paris Agreement. In this paper, we quantify fire foci, burned areas, and carbon emissions in all Brazilian biomes (i.e., Amazon, Cerrado, Caatinga, Atlantic Forest, Pantanal and Pampa). We analyzed these variables using cluster analysis and non-parametric statistics to predict carbon and CO2 emissions for the next decade. Our results showed no increase in the number of fire foci and carbon emissions for the evaluated time series, whereby the highest emissions occur and will persist in the Amazon and Cerrado biomes. The Atlantic Forest, Pantanal, Caatinga and Pampa biomes had low emissions compared to the Amazon and Cerrado. Based on 2030 projections, the sum of emissions from fire foci in the six Brazilian biomes will exceed 5.7 Gt CO2, compromising the national GHG reduction targets. To reduce GHG emissions, Brazil will need to control deforestation induced by the expansion of the agricultural frontier in the Amazon and Cerrado biomes. This can only be achieved through significant political effort involving the government, entrepreneurs and society as a collective.

Journal ArticleDOI
TL;DR: In this article, the main synthesis processes and new protocol modifications for the fabrication of magnetic photocatalysts, and their impact on the catalyst morphology, efficiency, and recycling are discussed.
Abstract: Photocatalysts have been widely applied in the degradation of organic compounds using visible and ultraviolet radiation. Different synthesis approaches have been developed and optimized to produce efficient, eco-friendly, and inexpensive materials to photo-treat water samples contaminated with dyes, pigments, pesticides, and other organic pollutants. Over the last two decades magnetic materials have emerged as a potential alternative to facilitate catalyst isolation in heterogeneously catalyzed liquid-phase reactions. In this review, we focus on the discussion of several studies including the main synthesis processes and new protocol modifications for the fabrication of magnetic photocatalysts, and their impact on the catalyst morphology, efficiency, and recycling. Emphasis is given on the discussion of the synthesis strategies over last decade to produce photoactive catalysts including single-phase catalysts, composites, Multifunctional metal–organic framework materials, binary and ternary core–shell materials, and yolk–shell photocatalysts.

Journal ArticleDOI
TL;DR: Endophytic bacteria-assisted phytoremediation contributed to reduce the substrate toxicity assessed in different model organisms and may help reduce environmental toxicity of mercury-contaminated soils.

Journal ArticleDOI
TL;DR: It is demonstrated that combining optical superresolution imaging with deep learning classification methods increases the speed and accuracy of assessing the biological affinities of fossil pollen taxa and raises the possibility that at least three Amherstieae genera may have diverged earlier in the Cenozoic than predicted by molecular phylogenies.
Abstract: Taxonomic resolution is a major challenge in palynology, largely limiting the ecological and evolutionary interpretations possible with deep-time fossil pollen data. We present an approach for fossil pollen analysis that uses optical superresolution microscopy and machine learning to create a quantitative and higher throughput workflow for producing palynological identifications and hypotheses of biological affinity. We developed three convolutional neural network (CNN) classification models: maximum projection (MPM), multislice (MSM), and fused (FM). We trained the models on the pollen of 16 genera of the legume tribe Amherstieae, and then used these models to constrain the biological classifications of 48 fossil Striatopollis specimens from the Paleocene, Eocene, and Miocene of western Africa and northern South America. All models achieved average accuracies of 83 to 90% in the classification of the extant genera, and the majority of fossil identifications (86%) showed consensus among at least two of the three models. Our fossil identifications support the paleobiogeographic hypothesis that Amherstieae originated in Paleocene Africa and dispersed to South America during the Paleocene-Eocene Thermal Maximum (56 Ma). They also raise the possibility that at least three Amherstieae genera (Crudia, Berlinia, and Anthonotha) may have diverged earlier in the Cenozoic than predicted by molecular phylogenies.


Journal ArticleDOI
01 Jun 2020-Ecology
TL;DR: It is suggested that ecological drift may drive variation in some small communities by changing the expected outcome of niche selection, increasing the chances of species with low abundance and narrow distribution to occur in some communities.
Abstract: Ecological drift can override the effects of deterministic niche selection on small populations and drive the assembly of some ecological communities. We tested this hypothesis with a unique data set sampled identically in 200 streams in two regions (tropical Brazil and boreal Finland) that differ in macroinvertebrate community size by fivefold. Null models allowed us to estimate the magnitude to which β-diversity deviates from the expectation under a random assembly process while taking differences in richness and relative abundance into account, i.e., β-deviation. We found that both abundance- and incidence-based β-diversity was negatively related to community size only in Brazil. Also, β-diversity of small tropical communities was closer to stochastic expectations compared with β-diversity of large communities. We suggest that ecological drift may drive variation in some small communities by changing the expected outcome of niche selection, increasing the chances of species with low abundance and narrow distribution to occur in some communities. Habitat destruction, overexploitation, pollution, and reductions in connectivity have been reducing the size of biological communities. These environmental pressures might make smaller communities more vulnerable to novel conditions and render community dynamics more unpredictable. Incorporation of community size into ecological models should provide conceptual and applied insights into a better understanding of the processes driving biodiversity.

Journal ArticleDOI
01 May 2020-Silicon
TL;DR: In this paper, the effect of foliar application with a soluble form of Si and salicylic acid (SA) in rice plants was evaluated under nitrogen deficiency conditions in Rice plants.
Abstract: Application of silicon (Si) and salicylic acid (SA) mitigates plant stress; however, this effect is not known under nitrogen (N) deficiency conditions in rice plants. The objective of the present study was to determine whether foliar application with a soluble form of Si and SA, individually or in combination, could mitigate N deficiency stress in rice plants. The treatments consisted of application of 3.45 g L−1 Si only (sprayed on the leaves), 4.5 mM SA only, a combination of both, and no application as control. Net CO2 assimilation rate, transpiration, lignin and carbon contents, C:N:P:Si stoichiometric ratio and grain yield were evaluated. Foliar application of Si combined with SA or isolated application of SA did not mitigate N deficiency stress in rice plants. However, silicon application increased rice yield by 18.6% in N-deficient conditions. Our results show that the beneficial effects of Si under nitrogen deficient conditions are related to the stoichiometry change in C with Si and increases of lignin synthesis.

Journal ArticleDOI
TL;DR: How these parasites might spread across regions due to global climate change and the importance of avian migratory behavior in parasite dispersion and subsequent diversification are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors compared the woody vegetation of the typical cerrado of the Cerrado-Amazonia Transition with that of the core area of Brazil in terms of both tree diversity and vegetation biomass.
Abstract: Less than half of the original two million square kilometers of the Cerrado vegetation remains standing, and there are still many uncertainties as to how to conserve and prioritize remaining areas effectively. A key limitation is the continuing lack of geographically-extensive evaluation of ecosystem-level properties across the biome. Here we sought to address this gap by comparing the woody vegetation of the typical cerrado of the Cerrado–Amazonia Transition with that of the core area of the Cerrado in terms of both tree diversity and vegetation biomass. We used 21 one-hectare plots in the transition and 18 in the core to compare key structural parameters (tree height, basal area, and above-ground biomass), and diversity metrics between the regions. We also evaluated the effects of temperature and precipitation on biomass, as well as explored the species diversity versus biomass relationship. We found, for the first time, both that the typical cerrado at the transition holds substantially more biomass than at the core, and that higher temperature and greater precipitation can explain this difference. By contrast, plot-level alpha diversity was almost identical in the two regions. Finally, contrary to some theoretical expectations, we found no positive relationship between species diversity and biomass for the Cerrado woody vegetation. This has implications for the development of effective conservation measures, given that areas with high biomass and importance for the compensation of greenhouse gas emissions are often not those with the greatest diversity.

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the suitability of using higher taxonomic level data to reveal species richness and compositional patterns independently of biological groups and ecosystem types and found that the strength of the HTA in describing biodiversity patterns decreased as the taxonomic resolution decreased.


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TL;DR: In this paper, the authors demonstrate how climate change will affect the ZEBs, considering as a parameter the Fourth Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC).