Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Trends Parasitol ; 39(9): 774-785, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37442747

RESUMO

Human leishmaniosis caused by Leishmania infantum is an important health problem worldwide. One of the main aspects arousing interest is the epidemiological scenario surrounding Le. infantum infection in the New World (NW) and Old World (OW). This parasite was introduced to the Americas during European colonization leading to different epidemiology outcomes, even more enigmatic in the face of global changes. Thus, this review aims to highlight the differences and similarities between Le. infantum epidemiology between Brazil (NW) and Spain (OW), as both countries are leading the total number of leishmaniosis cases in their respective continents. Grounded on a systemic view, this article also draws attention to possible common innovative strategies to rethink ways of controlling infections caused by Le. infantum.


Assuntos
Leishmania infantum , Leishmaniose Visceral , Leishmaniose , Parasitos , Animais , Humanos , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/parasitologia , Espanha/epidemiologia , Brasil/epidemiologia
2.
Neotrop Entomol ; 49(4): 545-556, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32557403

RESUMO

Nature safeguards living organisms and the ecosystem functions and services delivered by them. Animal pollination is an important Ecosystem Service since it plays a key role for achieving the sustainable development goals by safeguarding worldwide food production. Thus, conservation of pollination services is a major priority for guaranteeing global food security in the long term. Here we evaluate the crop pollination services in Pará state (Eastern Amazon, Brazil) focusing on two questions: (1) What is the economic value of crop production and pollination service in Pará? (2) Which municipalities are most dependent on pollination services considering local economies? We found 36 crops produced in the state; 20 (55%) crops are dependent on animal pollinators. In 2016, crop production value (CPV) for Pará state was US$ 2.95 billion and total pollination service value (PSV) was US$ 983.2 million, corresponding to 33% of CPV in Pará. Highest PSV value crops were açaí palm (US$635.6 million), cocoa (US$187.6 million), soybean (US$98.4 million), and watermelon (US$26.1 million), accounting for 96% of Pará's PSV. Two municipalities (Medicilândia and Igarapé Miri) presented more than 50% of their GDP based on pollination services. In general, we found low crop diversity in the municipalities of Pará, suggesting an economic rural vulnerability for the state, mainly supported by the high productions of soy and açaí. Pollinator conservation and ecological intensified farming practices are urgent for supporting sustainable development for the state.


Assuntos
Produção Agrícola/economia , Produtos Agrícolas/economia , Polinização , Brasil , Cacau , Citrullus , Ecossistema , Euterpe , Glycine max
3.
Ecology ; 99(5): 1203-1213, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29714828

RESUMO

Climate change and biodiversity loss are expected to simultaneously affect ecosystems, however research on how each driver mediates the effect of the other has been limited in scope. The multiple stressor framework emphasizes non-additive effects, but biodiversity may also buffer the effects of climate change, and climate change may alter which mechanisms underlie biodiversity-function relationships. Here, we performed an experiment using tank bromeliad ecosystems to test the various ways that rainfall changes and litter diversity may jointly determine ecological processes. Litter diversity and rainfall changes interactively affected multiple functions, but how depends on the process measured. High litter diversity buffered the effects of altered rainfall on detritivore communities, evidence of insurance against impacts of climate change. Altered rainfall affected the mechanisms by which litter diversity influenced decomposition, reducing the importance of complementary attributes of species (complementarity effects), and resulting in an increasing dependence on the maintenance of specific species (dominance effects). Finally, altered rainfall conditions prevented litter diversity from fueling methanogenesis, because such changes in rainfall reduced microbial activity by 58%. Together, these results demonstrate that the effects of climate change and biodiversity loss on ecosystems cannot be understood in isolation and interactions between these stressors can be multifaceted.


Assuntos
Mudança Climática , Ecossistema , Biodiversidade , Folhas de Planta
4.
Ecology ; 97(10): 2705-2715, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27859108

RESUMO

Habitat size and climate are known to affect the trophic structure and dynamics of communities, but their interactive effects are poorly understood. Organisms from different trophic levels vary in terms of metabolic requirements and heat dissipation. Indeed, larger species such as keystone predators require more stable climatic conditions than their prey. Likewise, habitat size disproportionally affects large-sized predators, which require larger home ranges and are thus restricted to larger habitats. Therefore, food web structure in patchy ecosystems is expected to be shaped by habitat size and climate variations. Here we investigate this prediction using natural aquatic microcosm (bromeliad phytotelmata) food webs composed of litter resources (mainly detritus), detritivores, mesopredators, and top predators (damselflies). We surveyed 240 bromeliads of varying sizes (water retention capacity) across 12 open restingas in SE Brazil spread across a wide range of tropical latitudes (-12.6° to -27.6°, ca. 2,000 km) and climates (Δ mean annual temperature = 5.3°C). We found a strong increase in predator-to-detritivore mass ratio with habitat size, which was representative of a typical inverted trophic pyramid in larger ecosystems. However, this relationship was contingent among the restingas; slopes of linear models were steeper in more stable and favorable climates, leading to inverted trophic pyramids (and top-down control) being more pronounced in environments with more favorable climatic conditions. By contrast, detritivore-resource and mesopredator-detritivore mass ratios were not affected by habitat size or climate variations across latitudes. Our results highlight that the combined effects of habitat size, climate and predator composition are pivotal to understanding the impacts of multiple environmental factors on food web structure and dynamics.


Assuntos
Ecossistema , Cadeia Alimentar , Animais , Brasil , Comportamento Predatório
5.
Braz. j. biol ; 76(2): 341-351, Apr.-June 2016. ilus, graf, tab
Artigo em Inglês | VETINDEX | ID: vti-25606

RESUMO

Abstract The semiarid region of northeastern Brazil, the Caatinga, is extremely important due to its biodiversity and endemism. Measurements of plant physiology are crucial to the calibration of Dynamic Global Vegetation Models (DGVMs) that are currently used to simulate the responses of vegetation in face of global changes. In a field work realized in an area of preserved Caatinga forest located in Petrolina, Pernambuco, measurements of carbon assimilation (in response to light and CO2) were performed on 11 individuals of Poincianella microphylla, a native species that is abundant in this region. These data were used to calibrate the maximum carboxylation velocity (Vcmax) used in the INLAND model. The calibration techniques used were Multiple Linear Regression (MLR), and data mining techniques as the Classification And Regression Tree (CART) and K-MEANS. The results were compared to the UNCALIBRATED model. It was found that simulated Gross Primary Productivity (GPP) reached 72% of observed GPP when using the calibrated Vcmax values, whereas the UNCALIBRATED approach accounted for 42% of observed GPP. Thus, this work shows the benefits of calibrating DGVMs using field ecophysiological measurements, especially in areas where field data is scarce or non-existent, such as in the Caatinga.(AU)


Resumo A região semiárida do nordeste do Brasil, a Caatinga, é extremamente importante devido à sua biodiversidade e endemismo. Medidas de fisiologia vegetal são cruciais para a calibração de Modelos de Vegetação Globais Dinâmicos (DGVMs) que são atualmente usados para simular as respostas da vegetação diante das mudanças globais. Em um trabalho de campo realizado em uma área de floresta preservada na Caatinga localizada em Petrolina, Pernambuco, medidas de assimilação de carbono (em resposta à luz e ao CO2) foram realizadas em 11 indivíduos de Poincianella microphylla, uma espécie nativa que é abundante nesta região. Estes dados foram utilizados para calibrar a velocidade máxima de carboxilação (Vcmax) usada no modelo INLAND. As técnicas de calibração utilizadas foram Regressão Linear Múltipla (MLR) e técnicas de mineração de dados como Classification And Regression Tree (CART) e K-MEANS. Os resultados foram comparados com o modelo INLAND não calibrado. Verificou-se que a Produtividade Primária Bruta (PPB) simulada atingiu 72% da PPB observada ao usar os valores de Vcmax calibrado, enquanto que o modelo não calibrado obteve-se 42% da PPB observada. Assim, este trabalho mostra os benefícios de calibrar DGVMs usando medidas ecofisiológicas de campo, especialmente em áreas onde os dados de campo são escassos ou inexistentes, como na Caatinga.(AU)


Assuntos
Mineração de Dados/métodos , Carboxina/análise , Carboxina/provisão & distribuição
6.
Braz. j. biol ; Braz. j. biol;76(2): 341-351, Apr.-June 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-781398

RESUMO

Abstract The semiarid region of northeastern Brazil, the Caatinga, is extremely important due to its biodiversity and endemism. Measurements of plant physiology are crucial to the calibration of Dynamic Global Vegetation Models (DGVMs) that are currently used to simulate the responses of vegetation in face of global changes. In a field work realized in an area of preserved Caatinga forest located in Petrolina, Pernambuco, measurements of carbon assimilation (in response to light and CO2) were performed on 11 individuals of Poincianella microphylla, a native species that is abundant in this region. These data were used to calibrate the maximum carboxylation velocity (Vcmax) used in the INLAND model. The calibration techniques used were Multiple Linear Regression (MLR), and data mining techniques as the Classification And Regression Tree (CART) and K-MEANS. The results were compared to the UNCALIBRATED model. It was found that simulated Gross Primary Productivity (GPP) reached 72% of observed GPP when using the calibrated Vcmax values, whereas the UNCALIBRATED approach accounted for 42% of observed GPP. Thus, this work shows the benefits of calibrating DGVMs using field ecophysiological measurements, especially in areas where field data is scarce or non-existent, such as in the Caatinga.


Resumo A região semiárida do nordeste do Brasil, a Caatinga, é extremamente importante devido à sua biodiversidade e endemismo. Medidas de fisiologia vegetal são cruciais para a calibração de Modelos de Vegetação Globais Dinâmicos (DGVMs) que são atualmente usados para simular as respostas da vegetação diante das mudanças globais. Em um trabalho de campo realizado em uma área de floresta preservada na Caatinga localizada em Petrolina, Pernambuco, medidas de assimilação de carbono (em resposta à luz e ao CO2) foram realizadas em 11 indivíduos de Poincianella microphylla, uma espécie nativa que é abundante nesta região. Estes dados foram utilizados para calibrar a velocidade máxima de carboxilação (Vcmax) usada no modelo INLAND. As técnicas de calibração utilizadas foram Regressão Linear Múltipla (MLR) e técnicas de mineração de dados como Classification And Regression Tree (CART) e K-MEANS. Os resultados foram comparados com o modelo INLAND não calibrado. Verificou-se que a Produtividade Primária Bruta (PPB) simulada atingiu 72% da PPB observada ao usar os valores de Vcmax calibrado, enquanto que o modelo não calibrado obteve-se 42% da PPB observada. Assim, este trabalho mostra os benefícios de calibrar DGVMs usando medidas ecofisiológicas de campo, especialmente em áreas onde os dados de campo são escassos ou inexistentes, como na Caatinga.


Assuntos
Árvores/classificação , Florestas , Caesalpinia/crescimento & desenvolvimento , Caesalpinia/fisiologia , Brasil , Calibragem , Modelos Lineares , Biodiversidade , Fenômenos Ecológicos e Ambientais , Aquecimento Global , Mineração de Dados/métodos , Modelos Biológicos
7.
Int J Biometeorol ; 60(7): 945-55, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26498437

RESUMO

Dynamic global vegetation models (DGVMs) simulate surface processes such as the transfer of energy, water, CO2, and momentum between the terrestrial surface and the atmosphere, biogeochemical cycles, carbon assimilation by vegetation, phenology, and land use change in scenarios of varying atmospheric CO2 concentrations. DGVMs increase the complexity and the Earth system representation when they are coupled with atmospheric global circulation models (AGCMs) or climate models. However, plant physiological processes are still a major source of uncertainty in DGVMs. The maximum velocity of carboxylation (Vcmax), for example, has a direct impact over productivity in the models. This parameter is often underestimated or imprecisely defined for the various plant functional types (PFTs) and ecosystems. Vcmax is directly related to photosynthesis acclimation (loss of response to elevated CO2), a widely known phenomenon that usually occurs when plants are subjected to elevated atmospheric CO2 and might affect productivity estimation in DGVMs. Despite this, current models have improved substantially, compared to earlier models which had a rudimentary and very simple representation of vegetation-atmosphere interactions. In this paper, we describe this evolution through generations of models and the main events that contributed to their improvements until the current state-of-the-art class of models. Also, we describe some main challenges for further improvements to DGVMs.


Assuntos
Modelos Teóricos , Fenômenos Fisiológicos Vegetais , Aclimatação , Dióxido de Carbono , Temperatura
8.
Braz. J. Biol. ; 76(2)2016.
Artigo em Inglês | VETINDEX | ID: vti-744838

RESUMO

Abstract The semiarid region of northeastern Brazil, the Caatinga, is extremely important due to its biodiversity and endemism. Measurements of plant physiology are crucial to the calibration of Dynamic Global Vegetation Models (DGVMs) that are currently used to simulate the responses of vegetation in face of global changes. In a field work realized in an area of preserved Caatinga forest located in Petrolina, Pernambuco, measurements of carbon assimilation (in response to light and CO2) were performed on 11 individuals of Poincianella microphylla, a native species that is abundant in this region. These data were used to calibrate the maximum carboxylation velocity (Vcmax) used in the INLAND model. The calibration techniques used were Multiple Linear Regression (MLR), and data mining techniques as the Classification And Regression Tree (CART) and K-MEANS. The results were compared to the UNCALIBRATED model. It was found that simulated Gross Primary Productivity (GPP) reached 72% of observed GPP when using the calibrated Vcmax values, whereas the UNCALIBRATED approach accounted for 42% of observed GPP. Thus, this work shows the benefits of calibrating DGVMs using field ecophysiological measurements, especially in areas where field data is scarce or non-existent, such as in the Caatinga.


Resumo A região semiárida do nordeste do Brasil, a Caatinga, é extremamente importante devido à sua biodiversidade e endemismo. Medidas de fisiologia vegetal são cruciais para a calibração de Modelos de Vegetação Globais Dinâmicos (DGVMs) que são atualmente usados para simular as respostas da vegetação diante das mudanças globais. Em um trabalho de campo realizado em uma área de floresta preservada na Caatinga localizada em Petrolina, Pernambuco, medidas de assimilação de carbono (em resposta à luz e ao CO2) foram realizadas em 11 indivíduos de Poincianella microphylla, uma espécie nativa que é abundante nesta região. Estes dados foram utilizados para calibrar a velocidade máxima de carboxilação (Vcmax) usada no modelo INLAND. As técnicas de calibração utilizadas foram Regressão Linear Múltipla (MLR) e técnicas de mineração de dados como Classification And Regression Tree (CART) e K-MEANS. Os resultados foram comparados com o modelo INLAND não calibrado. Verificou-se que a Produtividade Primária Bruta (PPB) simulada atingiu 72% da PPB observada ao usar os valores de Vcmax calibrado, enquanto que o modelo não calibrado obteve-se 42% da PPB observada. Assim, este trabalho mostra os benefícios de calibrar DGVMs usando medidas ecofisiológicas de campo, especialmente em áreas onde os dados de campo são escassos ou inexistentes, como na Caatinga.

9.
Inf. epidemiol. SUS ; 11(3): 13-154, jul.-set. 2002. tab
Artigo em Português | LILACS | ID: lil-348700

RESUMO

Neste artigo busca-se inventariar o estado atual das inter-relações entre mudanças ambientais globais e saúde, incluindo uma revisão do estado atual das ameaças de origem antrópica sobre a biodiversidade, trazendo o enfoque ecossitêmico como linha de pesquisa para a melhoria da qualidade de vida. Os processos de mudanças ambientais globais afetam a saúde humana, direta ou indiretamente, pontual ou regionalmente. Alterações na química da atmosfera, mudanças climáticas, degradação do solo, perda da biodiversidade, urbanização e grandes empreendimentos, escassez de água e poluições químicas de âmbito global podem ter consequências severas para o bem-estar humano, saúde e sobrevivência. A importância dessas mudanças para a saúde humana dependerá de quanto as populações são ou podem ser afetadas no futuro, do grau e amplitude dos impactos e das adaptações biológicas e das formas de mitigação e controle disponíveis. Vários programas têm sido desenvolvidos em todo o mundo, mas é preciso avançar em modelos conceituais, incluir as questões das mudanças ambientais globais na agenda científica e institucional brasileira, buscar modelos de desenvolvimento sustentável, criar mecanismos que interropam a perda da biodiversidade, minimizar o uso de poluentes e sensibilizar as pessoas para o possível esgotamento dos recursos naturais renováveis


In this article we intended to survey the current state of relationships between global environmental changes and health. It includes a revision of the current state of threats of anthropic origin on biodiversity, bringing an ecosystem approach as a field of research for the improvement of quality of life. Global environmental changes affect human health directly or indirectly, locally or regionally. Alterations in the chemistry of the atmosphere, climate changes, soil degradation, loss of biodiversity, urbanization and major development sites, shortage of water and chemical pollutants constitute driving forces that can have severe consequences for human well-being and health as well as, its survival. The importance of these changes for human health will depend on how populations may be affected in the future, the severity and magnitude of the impact, the possibility of biological adaptations, and the availability of strategies to mitigate and control. Several programs have been developed around the world. However, the Brazilian scientific and institutional agenda needs to move forward in conceptual models that include aspects related to global environmental changes, searching for models of sustainable development, and creating mechanisms that interrupt the loss of biodiversity, minimize the use of pollutants, establish awareness programs concerning the exhaustion of renewable natural resources.


Assuntos
Humanos , Riscos Ambientais , Meio Ambiente , Desenvolvimento Ecológico , Saúde
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA