126 research outputs found

    AVALIAÇÃO DA REGENERAÇÃO NATURAL EM ÁREA DE RESTAURAÇÃO ECOLÓGICA E MATA CILIAR DE REFERÊNCIA

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    Riparian areas are a recurrent focus of ecological restoration due to their importance for the maintenance of ecosystem services. However, few studies have evaluated the success of active interventions in restoring ecosystem functions and processes. The natural regeneration is a successional process and its evaluation might reveal the state and the potential of the ecosystem resilience in forest areas undergoing restoration. The present study aimed to compare natural regeneration of a riparian area that is undergoing restoration (planting of native trees, 10 years ago) with a reference forest area, in Cachoeirinha, Rio Grande do Sul state, Brazil. We conducted a survey of trees and shrubs in the upper stratum (DBH ≥ 5 cm) and the lower stratum (> 30 cm in height and DBH > 5 cm) in a total of 40 plots (100 m2 each), within the planting (restoration) and the remnant forest (reference). For each stratum and treatment (reference vs. restoration) we analyzed phytosociological parameters, patterns of structure and composition, and similarity among plots. The results showed significant differences in relation to structure and species composition, especially for the upper stratum. For the lower stratum (natural regeneration), abundance, height, and species richness were similar between the restoration and the reference areas. Species composition in regeneration remained distinct. However, its similarity value was higher than any other comparison among strata, indicating that species that were not planted were able to establish in the planted areas.Áreas ribeirinhas são foco recorrente de restauração ecológica, devido a sua importância para a manutenção de serviços ecossistêmicos. Entretanto, poucos estudos têm de fato avaliado o sucesso de intervenções ativas em restaurar funções ou processos ecossistêmicos. A regeneração natural é um processo sucessional, cuja avaliação pode indicar o estado e o potencial de resiliência do ecossistema em áreas sob restauração. O presente estudo comparou padrões de regeneração natural de uma área de restauração ecológica (com plantio de mudas nativas há 10 anos) com a mata ciliar de referência, em Cachoeirinha, Rio Grande do Sul, Brasil. Para tanto, foi realizado o levantamento das espécies arbóreas e arbustivas presentes no estrato superior (DAP ≥ 5 cm) e inferior (altura > 30 cm e DAP < 5 cm), em 40 parcelas de 100 m² cada, considerando o plantio (restauração) e a mata ciliar remanescente (referência). Cada estrato e tratamento (referência vs. restauração) foi avaliado quanto aos descritores fitossociológicos, padrões de estrutura e composição, riqueza e similaridade entre as comunidades. Os resultados demonstraram que a área de restauração apresenta composição de espécies e estrutura diferenciada com relação à referência, especialmente para o estrato superior. No estrato inferior (regeneração natural), o número de indivíduos, a altura média e a riqueza de espécies já não diferiram da referência. A composição de espécies em regeneração ainda foi distinta, porém, esta foi mais similar entre si do que as demais comparações entre estratos, indicando que espécies não plantadas foram capazes de se estabelecer nas áreas de restauração

    EVALUATION OF THE NATURAL REGENERATION IN A RESTORATION PLANTING AREA AND IN A REFERENCE RIPARIAN FOREST

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    \uc1reas ribeirinhas s\ue3o foco recorrente de restaura\ue7\ue3o ecol\uf3gica, devido a sua import\ue2ncia para a manuten\ue7\ue3o de servi\ue7os ecossist\ueamicos. Entretanto, poucos estudos t\ueam de fato avaliado o sucesso de interven\ue7\uf5es ativas em restaurar fun\ue7\uf5es ou processos ecossist\ueamicos. A regenera\ue7\ue3o natural \ue9 um processo sucessional, cuja avalia\ue7\ue3o pode indicar o estado e o potencial de resili\ueancia do ecossistema em \ue1reas sob restaura\ue7\ue3o. O presente estudo comparou padr\uf5es de regenera\ue7\ue3o natural de uma \ue1rea de restaura\ue7\ue3o ecol\uf3gica (com plantio de mudas nativas h\ue1 10 anos) com a mata ciliar de refer\ueancia, em Cachoeirinha, Rio Grande do Sul, Brasil. Para tanto, foi realizado o levantamento das esp\ue9cies arb\uf3reas e arbustivas presentes no estrato superior (DAP 65 5 cm) e inferior (altura &gt; 30 cm e DAP &lt; 5 cm), em 40 parcelas de 100 m\ub2 cada, considerando o plantio (restaura\ue7\ue3o) e a mata ciliar remanescente (refer\ueancia). Cada estrato e tratamento (refer\ueancia vs. restaura\ue7\ue3o) foi avaliado quanto aos descritores fitossociol\uf3gicos, padr\uf5es de estrutura e composi\ue7\ue3o, riqueza e similaridade entre as comunidades. Os resultados demonstraram que a \ue1rea de restaura\ue7\ue3o apresenta composi\ue7\ue3o de esp\ue9cies e estrutura diferenciada com rela\ue7\ue3o \ue0 refer\ueancia, especialmente para o estrato superior. No estrato inferior (regenera\ue7\ue3o natural), o n\ufamero de indiv\uedduos, a altura m\ue9dia e a riqueza de esp\ue9cies j\ue1 n\ue3o diferiram da refer\ueancia. A composi\ue7\ue3o de esp\ue9cies em regenera\ue7\ue3o ainda foi distinta, por\ue9m, esta foi mais similar entre si do que as demais compara\ue7\uf5es entre estratos, indicando que esp\ue9cies n\ue3o plantadas foram capazes de se estabelecer nas \ue1reas de restaura\ue7\ue3o.Riparian areas are a recurrent focus of ecological restoration due to their importance for the maintenance of ecosystem services. However, few studies have evaluated the success of active interventions in restoring ecosystem functions and processes. The natural regeneration is a successional process and its evaluation might reveal the state and the potential of the ecosystem resilience in forest areas undergoing restoration. The present study aimed to compare natural regeneration of a riparian area that is undergoing restoration (planting of native trees, 10 years ago) with a reference forest area, in Cachoeirinha, Rio Grande do Sul state, Brazil. We conducted a survey of trees and shrubs in the upper stratum (DBH 65 5 cm) and the lower stratum (&gt; 30 cm in height and DBH &gt; 5 cm) in a total of 40 plots (100 m2 each), within the planting (restoration) and the remnant forest (reference). For each stratum and treatment (reference vs. restoration) we analyzed phytosociological parameters, patterns of structure and composition, and similarity among plots. The results showed significant differences in relation to structure and species composition, especially for the upper stratum. For the lower stratum (natural regeneration), abundance, height, and species richness were similar between the restoration and the reference areas. Species composition in regeneration remained distinct. However, its similarity value was higher than any other comparison among strata, indicating that species that were not planted were able to establish in the planted areas

    Common diseases alter the physiological age-related blood microRNA profile

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    Aging is a key risk factor for chronic diseases of the elderly. MicroRNAs regulate post-transcriptional gene silencing through base-pair binding on their target mRNAs. We identified nonlinear changes in age-related microRNAs by analyzing whole blood from 1334 healthy individuals. We observed a larger influence of the age as compared to the sex and provide evidence for a shift to the 5' mature form of miRNAs in healthy aging. The addition of 3059 diseased patients uncovered pan-disease and disease-specific alterations in aging profiles. Disease biomarker sets for all diseases were different between young and old patients. Computational deconvolution of whole-blood miRNAs into blood cell types suggests that cell intrinsic gene expression changes may impart greater significance than cell abundance changes to the whole blood miRNA profile. Altogether, these data provide a foundation for understanding the relationship between healthy aging and disease, and for the development of age-specific disease biomarkers

    Dynamic Contrast-Enhanced MRI Assessment of Hyperemic Fractional Microvascular Blood Plasma Volume in Peripheral Arterial Disease: Initial Findings

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    OBJECTIVES: The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) to assess the microvascular status in patients with peripheral arterial disease (PAD) and healthy controls. In addition, the reproducibility of this method in healthy controls was determined. MATERIALS AND METHODS: Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (V(p), unit: %) of the anterior tibial, gastrocnemius and soleus muscles was calculated. RESULTS: V(p) was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively) compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%). Differences in V(p) between muscle groups were not significant. The coefficient of variation of V(p) varied from 10-14% and 11-16% at interscan and interreader level, respectively. CONCLUSIONS: Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. V(p) was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic) biomarker for the microvascular impairment of macrovascular lesions

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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