4,681 research outputs found

    Principais mosquitos de importância sanitária no Brasil

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    Traz informações concisas e atualizadas sobre os mosquitos vetores de doenças no Brasil. Inclui morfologia e biologia das fases evolutivas de adulto, ovo, larva e pupa, abordando aspectos referentes à nutrição, reprodução, comportamento e ecologia. Com referência às medidas de controle, são abordados os métodos químicos, a questão da resistência aos inseticidas e a perspectiva dos métodos biológicos. Possui, ainda, técnicas de trabalho e uma vasta lista de referências bibliográficas para um conhecimento mais detalhado de cada item tratado

    Rainfall Prediction in the State of Paraíba, Northeastern Brazil Using Generalized Additive Models

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    The state of Paraíba is part of the semi-arid region of Brazil, where severe droughts have occurred in recent years, resulting in significant socio-economic losses associated with climate variability. Thus, understanding to what extent precipitation can be influenced by sea surface temperature (SST) patterns in the tropical region can help, along with a monitoring system, to set up an early warning system, the first pillar in drought management. In this study, Generalized Additive Models for Location, Scale and Shape (GAMLSS) were used to filter climatic indices with higher predictive efficiency and, as a result, to perform rainfall predictions. The results show the persistent influence of tropical SST patterns in Paraíba rainfall, the tropical Atlantic Ocean impacting the rainfall distribution more effectively than the tropical Pacific Ocean. The GAMLSS model showed predictive capability during summer and southern autumn in Paraíba, highlighting the JFM (January, February and March), FMA (February, March and April), MAM (March, April and May), and AMJ (April, May and June) trimesters as those with the highest predictive potential. The methodology demonstrates the ability to be integrated with regional forecasting models (ensemble). Such information has the potential to inform decisions in multiple sectors, such as agriculture and water resources, aiming at the sustainable management of water resources and resilience to climate risk

    Photochemical efficiency of Brachiaria brizantha under Eucalyptus canopies in an ILF system.

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    Brazilian livestock farming is an essential part of the country's economy, standing out as one of the largest sectors of national agribusiness. Challenges such as the search for environmental sustainability require appropriate management for soil conservation and the development of the livestock sector. The integrated livestock-forestry (ILF) system is a sustainable technique that aims to integrate different production systems in the same area, making better use of natural resources. The choice of tree species to be implemented in the system is highly relevant, as it affects the luminosity available to the species that grow under its canopy, affecting determining characteristics associated with the productivity and quality of the pasture. The aim of this study was to evaluate the influence of luminosity in the understory of an ILF system on the photosynthetic activity of the Brachiaria brizantha species in an Atlantic Forest region. To do this, chlorophyll a fluorescence analyses were carried out on forage plants grown in a consortium with Eucalyptus urograndis (Clone 1407), with spacing between the trees of 4m and 24m between the crop rows. The treatments were established according to two lighting conditions: the control treatment corresponding to the condition with the highest lighting (between the planting rows) and the treatment with the lowest lighting corresponding to the area under the canopy of the eucalyptus trees (in the crop row). The results show that the low light supplied to the B. brizantha forage promotes low efficiency in the electron transport chain, indicating a possible stress situation

    Photochemical efficiency of Brachiaria brizantha under Eucalyptus canopies in an ILF system.

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    Brazilian livestock farming is an essential part of the country's economy, standing out as one of the largest sectors of national agribusiness. Challenges such as the search for environmental sustainability require appropriate management for soil conservation and the development of the livestock sector. The integrated livestock-forestry (ILF) system is a sustainable technique that aims to integrate different production systems in the same area, making better use of natural resources. The choice of tree species to be implemented in the system is highly relevant, as it affects the luminosity available to the species that grow under its canopy, affecting determining characteristics associated with the productivity and quality of the pasture. The aim of this study was to evaluate the influence of luminosity in the understory of an ILF system on the photosynthetic activity of the Brachiaria brizantha species in an Atlantic Forest region. To do this, chlorophyll a fluorescence analyses were carried out on forage plants grown in a consortium with Eucalyptus urograndis (Clone 1407), with spacing between the trees of 4m and 24m between the crop rows. The treatments were established according to two lighting conditions: the control treatment corresponding to the condition with the highest lighting (between the planting rows) and the treatment with the lowest lighting corresponding to the area under the canopy of the eucalyptus trees (in the crop row). The results show that the low light supplied to the B. brizantha forage promotes low efficiency in the electron transport chain, indicating a possible stress situation

    Dengue Infection Increases the Locomotor Activity of Aedes aegypti Females

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    BACKGROUND: Aedes aegypti is the main vector of the virus causing Dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. It is known that viruses and other parasites can potentially alter vector behavior. We investigated whether infection with Dengue virus modifies the behavior of Aedes aegypti females with respect to their activity level. METHODS/PRINCIPAL FINDINGS: We carried out intrathoracic Dengue 2 virus (DENV-2) infections in Aedes aegypti females and recorded their locomotor activity behavior. We observed an increase of up to ∼50% in the activity of infected mosquitoes compared to the uninfected controls. CONCLUSIONS: Dengue infection alters mosquito locomotor activity behavior. We speculate that the higher levels of activity observed in infected Aedes aegypti females might involve the circadian clock. Further studies are needed to assess whether this behavioral change could have implications for the dynamics of Dengue virus transmission

    Limited risk of Zika virus transmission by five Aedes albopictus populations from Spain

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    Background: Aedes albopictus, the Asian tiger mosquito, is an exotic invasive species in Europe. It has substantial public health relevance due to its potential role in transmitting several human pathogens. Out of the European coun‑ tries, Spain has one of the highest risk levels of autochthonous arbovirus transmission due to both the high density of Ae. albopictus and the extensive tourist infux from vector-endemic areas. This study aims to investigate the suscep‑ tibility of fve Ae. albopictus populations from mainland Spain and the Balearic Islands to a Brazilian Zika virus (ZIKV) strain. Methods: The F1 generation of each Ae. albopictus population was orally challenged with a ZIKV-infected blood meal (1.8×106 PFU/ml). At 7 and 14 days post-infection (dpi), mosquito bodies (thorax and abdomen) and heads were individually analysed through RT-qPCR to determine the infection rate (IR) and dissemination rate (DR), respectively. The saliva of infected mosquitoes was inoculated in Vero cells and the transmission rate was assessed by plaque assay or RT-qPCR on ~33 individuals per population. Results: The IR and DR ranged between 12–88%, and 0–60%, respectively, suggesting that ZIKV is capable of cross‑ ing the midgut barrier. Remarkably, no infectious viral particle was found in saliva samples, indicating a low ability of ZIKV to overcome the salivary gland barrier. A subsequent assay revealed that a second non-infective blood meal 48 h after ZIKV exposure did not infuence Ae. albopictus vector competence. Conclusions: The oral experimental ZIKV infections performed here indicate that Ae. albopictus from Spain become infected and disseminate the virus through the body but has a limited ability to transmit the Brazilian ZIKV strain through biting. Therefore, the results suggest a limited risk of autochthonous ZIKV transmission in Spain by Ae. albopictusinfo:eu-repo/semantics/publishedVersio

    Evaluation of photosynthetic variables of Brachiaria brizantha under eucalyptus canopies in a livestock-forestry integration system.

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    Livestock sector generates significant environmental impacts despite its global economic importance. The current challenge is to find sustainable ways of boosting this sector, while mitigating the negative impacts of this activity. In Brazil, degraded pastures are common because of inadequate management, damaging the soil. Integrated livestock-forestry (ILF) systems combine forest species and pastures in the area, incorporating elements of sustainability. In this system, the tree species is related to the productivity of the pasture, as the shade generated by the canopy creates different light conditions, influencing the photosynthetic activity of the forage. The aim of this study was to evaluate the influence of the luminosity of the understory of an ILF system on the photosynthetic activity of the forage species Brachiaria brizantha in the Atlantic Forest region of Brazil. Transient chlorophyll a fluorescence and chlorophyll concentration were analysed in forage plants grown in consortium with Eucalyptus urograndis (Clone 1407), with spacing of 4m between trees and 24m between tree rows. Two treatments were established based on light conditions: the control treatment, corresponding to the condition with the highest light corresponded to the pasture row, and the treatment with the lowest light, corresponding to the area under the canopy. The results show that the low light supplied to the forage plant, during the experiment period, under eucalyptus canopies, promotes changes in the intensity of chlorophyll a fluorescence and chlorophyll concentration, indicating low efficiency of the electron transport chain and changes in leaf nitrogen content, due to a possible stress situation
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