1,324 research outputs found

    Impacts of land use change on ecosystems and society in the Rio de La Plata basin.

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    The La Plata river basin (LPB) covers an area of 3.1 million km2 with a population of over 100 million people of Argentina, Bolivia, Brazil, Paraguay, and Uruguay. The LPB covers a wide geographical area, spanning a South to North latitudinal gradient, resulting in the establishment of a variety of soil - vegetation configurations, as a response to different climates. The inherent topographic heterogeneity of the LPB adds natural complexity to the basin, resulting in a combination of extensive savannah-like plateaus (cerrado) and grasslands and open fields (pampas) in its Northern and Southern portions, respectively, the largest tropical wetland area in the world in the Northwest (pantanal), as well as both dry and humid forest biomes (chaco and Atlantic forests, respectively). This varied composition of biomes and ecosystems, added to the different social and cultural setup of the LPB, resulted in diverse histories and complex patterns of land use in the basin. Rural land use and industry in the basin are responsible for 70% of the Gross National Products of the LPB countries and are in a process of continuous change, as a response to drivers such as international market trends, infra-structure and technology developments, societal evolution, and the dynamics of national policies. Possible land use changes (LUC) are limited by biophysical constraints such as unsuitable soil type, topography, or climate. However, technology development can overcome some of these limitations, as was the case of the soybean expansion to the Cerrado region of Brazil, in the eighties. Effective and sustainable management of the LPB depends on the ability of land managers from the five nations to predict the impacts LUCs on nature and society. Modeling efforts to predict environmental impacts in the LPB can benefit from knowledge acquired from impact assessments of major LUC processes. Land use change affects both the natural environment and society, therefore impact indicators should represent both dimensions. The human and natural dimensions interact both as drivers and as recipients of the impacts of LUC. The altered state of the impacted human and natural dimensions will reconfigure them as altered LUC drivers. Understanding these feedback mechanisms is a great challenge that integrates natural and social sciences. There is an urgent need for interdisciplinary research, overcoming inherent conceptual and epistemologic barriers. Decision makers and society will only act on response to global change science results, when social and natural scientists achieve an effective integrated research framework

    Roles of plant volatiles in defence against microbial pathogens and microbial exploitation of volatiles

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    Plants emit a large variety of volatile organic compounds during infection by pathogenic microbes, including terpenes, aromatics, nitrogen‐containing compounds, and fatty acid derivatives, as well as the volatile plant hormones, methyl jasmonate, and methyl salicylate. Given the general antimicrobial activity of plant volatiles and the timing of emission following infection, these compounds have often been assumed to function in defence against pathogens without much solid evidence. In this review, we critically evaluate current knowledge on the toxicity of volatiles to fungi, bacteria, and viruses and their role in plant resistance as well as how they act to induce systemic resistance in uninfected parts of the plant and in neighbouring plants. We also discuss how microbes can detoxify plant volatiles and exploit them as nutrients, attractants for insect vectors, and inducers of volatile emissions, which stimulate immune responses that make plants more susceptible to infection. Although much more is known about plant volatile–herbivore interactions, knowledge of volatile–microbe interactions is growing and it may eventually be possible to harness plant volatiles to reduce disease in agriculture and forestry. Future research in this field can be facilitated by making use of the analytical and molecular tools generated by the prolific research on plant–herbivore interactions.A. H. and T. A. are funded by South African National Research Council Incentive Funds (2019) and the University of Pretoria, and J. G. is funded by the Max Planck Society.https://wileyonlinelibrary.com/journal/pce2020-10-01hj2020BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyZoology and Entomolog

    Los medios de comunicación entre la cuarta y la quinta potencia/estado: análisis de la segunda ronda de las elecciones presidenciales 2018 en Brasil

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    El objetivo de este artículo es evaluar a los medios tradicionales brasileños que llegaron a ser conocidos como cuarto poder, en referencia a los medios como inspectores de los tres poderes que rigen el gobierno nacional: ejecutivo, legislativo y judicial, y que Dutton (2009) llama la quinta potencia/estado, basada en internet. Se analiza la cuenta Instagram oficial de Bolsonaro, además de asuntos del Jornal Nacional (Rede Globo) en la segunda vuelta de las elecciones presidenciales. La metodología es el Análisis de la Materialidad Audiovisual, propuesta por Coutinho (2016), que busca entender el lenguaje audiovisual como una unidad. El quinto potencia/estado ha ganado fuerza creciente en esta coalición con los medios de comunicación, y fue decisivo para que Bolsonaro ganara las elecciones.The aim of this article is to evaluate the traditional Brazilian media that came to be known as the fourth estate, in reference to the media as inspectors of the three branches that govern the national government: executive, legislative and judicial, and which Dutton (2009) calls the fifth power/state, based on the internet. Bolsonaro's official Instagram account is analysed, in addition to issues of the Jornal Nacional (Rede Globo) in the second round of the presidential elections. The methodology is the Analysis of Audiovisual Materiality, proposed by Coutinho (2016), which seeks to understand audiovisual language as a unit. The fifth power/state has gained increasing strength in this coalition with the media, and was decisive for Bolsonaro to win the election.Ciencias de la Comunicació

    A Cluster-Randomised Trial to Compare Home-Based with Health Facility-Based Antiretroviral Treatment in Uganda: Study Design and Baseline Findings

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    The scale-up of antiretroviral therapy is progressing rapidly in Africa but with a limited evidence-base. We report the baseline results from a large pragmatic cluster-randomised trial comparing different strategies of ART delivery. The trial is integrated in normal health service delivery. 1453 subjects were recruited into the study. Significantly more women (71%) than men (29%) were recruited. The WHO HIV clinical stage at presentation did not differ significantly between men and women: 58% and 53% respectively were at WHO stage III or IV (p=0.9). Median CD4 counts (IQR) x 106cells/l were 98 (28, 160) among men and 111 (36, 166) among women. Sixty-four percent of women and 61% men had plasma viral load ≥100,000 copies. Baseline characteristics did not change over time. Considerably fewer men than women presented for treatment. Both men and women presented at an advanced stage with very low median CD4 count and high plasma viral load

    Decompressive hemicraniectomy in severe cerebral venous thrombosis: a prospective case series

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    Small retrospective case series suggest that decompressive hemicraniectomy can be life saving in patients with cerebral venous thrombosis (CVT) and impending brain herniation. Prospective studies of consecutive cases are lacking. Thus, a single centre, prospective study was performed. In 2006 we adapted our protocol for CVT treatment to perform acute decompressive hemicraniectomy in patients with impending herniation, in whom the prognosis with conservative treatment was considered infaust. We included all consecutive patients with CVT between 2006 and 2010 who underwent hemicraniectomy. Outcome was assessed at 12 months with the modified Rankin Scale (mRS). Ten patients (8 women) with a median age of 41 years (range 26–52 years) were included. Before surgery 5 patients had GCS < 9, 9 patients had normal pupils, 1 patient had a unilaterally fixed and dilated pupil. All patients except one had space-occupying intracranial hemorrhagic infarcts. The median preoperative midline shift was 9 mm (range 3–14 mm). Unilateral hemicraniectomy was performed in 9 patients and bilateral hemicraniectomy in one. Two patients died from progressive cerebral edema and expansion of the hemorrhagic infarcts. Five patients recovered without disability at 12 months (mRS 0–1). Two patients had some residual handicap (one minor, mRS 2; one moderate, mRS 3). One patient was severely handicapped (mRS 5). Our prospective data show that decompressive hemicraniectomy in the most severe cases of cerebral venous thrombosis was probably life saving in 8/10 patients, with a good clinical outcome in six. In 2 patients death was caused by enlarging hemorrhagic infarcts

    a systematic review

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    © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.OBJECTIVES: Current guidelines do not recommend direct oral anticoagulants (DOACs) to treat cerebral venous thrombosis (CVT) despite their benefits over standard therapy. We performed a systematic review to summarise the published experience of DOAC therapy in CVT. DATA SOURCES: MEDLINE, Embase and COCHRANE databases up to 18 November 2020. ELIGIBILITY CRITERIA: All published articles of patients with CVT treated with DOAC were included. Studies without follow-up information were excluded. DATA EXTRACTION AND SYNTHESIS: Two independent reviewers screened articles and extracted data. A risk of bias analysis was performed. PRIMARY AND SECONDARY OUTCOME MEASURES: Safety data included mortality, intracranial haemorrhage (ICH) or other adverse events. Efficacy data included recurrent CVT, recanalisation rates and disability by modified Rankin Scales (mRS). RESULTS: 33 studies met inclusion criteria. One randomised controlled trial, 5 observational cohorts and 27 case series or studies reported 279 patients treated with DOAC for CVT: 41% dabigatran, 47% rivaroxaban, 10% apixaban and 2% edoxaban, in addition to 315 patients treated with standard therapy. The observational cohorts showed a similar risk of death in DOAC and standard therapy arms (RR 2.12, 95% CI 0.29 to 15.59). New ICH was reported in 2 (0.7%) DOAC-treated patients and recurrent CVT occurred in 4 (1.5%). A favourable mRS between 0 and 2 was reported in 94% of DOAC-treated patients, more likely than standard therapy in observational cohorts (RR 1.13, 95% CI 1.02 to 1.25). CONCLUSION: The evidence for DOAC use in CVT is limited although suggests sufficient safety and efficacy despite variability in timing and dose of treatment. This systematic review highlights that further rigorous trials are needed to validate these findings and to determine optimal treatment regimens.publishersversionpublishe
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