520 research outputs found

    The detection of post-monsoon tropospheric ozone variability over south Asia using IASI data

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    The ozone (O<sub>3</sub>) variability over south Asia during the 2008 post-monsoon season has been assessed using measurements from the MetOP-A/IASI instrument and O<sub>3</sub> profiles retrieved with the SOftware for a Fast Retrieval of IASI Data (SOFRID). The information content study and error analyses carried out in this paper show that IASI Level 1 data can be used to retrieve tropospheric O<sub>3</sub> columns (TOC, surface-225 hPa) and UTLS columns (225–70 hPa) with errors smaller than 20%. Validation with global radiosonde O<sub>3</sub> profiles obtained during a period of 6 months show the excellent agreement between IASI and radiosonde for the UTLS with correlation coefficient <i>R</i> > 0.91 and good agreement in the troposphere with correlation coefficient <i>R</i> > 0.74. For both the UTLS and the troposphere Relative Standard Deviations (RSD) are lower than 23%. Comparison with in-situ measurements from the MOZAIC program around Hyderabad demonstrates that IASI is able to capture the TOC inter and intra-seasonal variability in central India. Nevertheless, the agreement is mitigated by the fact that the smoothing of the true O<sub>3</sub> profiles by the retrieval results in a reduction of the TOC variability detected by IASI relative to the variability observed by in situ instruments. The post-monsoon temporal variability of the vertical profile of O<sub>3</sub> around Hyderabad has been investigated with MOZAIC observations. These observations from airborne instruments show that tropospheric O<sub>3</sub> is steadily elevated during most of the studied period with the exception of two sharp drops following the crossing of tropical storms over India. Lagrangian simulations with the FLEXPART model indicate that elevated O<sub>3</sub> concentrations in the middle troposphere near Hyderabad are associated with the transport of UTLS air-masses that have followed the Subtropical Westerly Jet (SWJ) and subsided over northern India together with boundary layer polluted air-masses transported from the Indo-gangetic plain by the north-easterly trades. Low O<sub>3</sub> concentrations result from the uplift and westward transport of pristine air-masses from the marine boundary layer of the Bay of Bengal by tropical storms. In order to extend the analysis of tropospheric O<sub>3</sub> variability to the whole of south Asia, we have used IASI-SOFRID O<sub>3</sub> data. We show that IASI O<sub>3</sub> data around Hyderabad were able to capture the fast variability revealed by MOZAIC. Furthermore, their spatio-temporal coverage demonstrates that the behaviour of tropospheric O<sub>3</sub> observed near Hyderabad extended over most of central and south India and part of the Bay of Bengal. This result highlights the ability of the IASI sensor to capture fast changes in chemical composition related to dramatic tropical weather conditions

    Effects of landscape fragmentation on soil loss in the Cerrado Biome, Brazil.

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    Soil loss stands as a critical global challenge, posing economic and environmental threats to soil and water conservation. This study aimed to assess the impact of landscape changes on soil loss in the Descoberto River basin, encompassing 62 watersheds in the Cerrado biome in central Brazil. We analysed a 32-year time series (1985−2017) of land use and land cover data based on geostatistical techniques and spatiotemporal weighted regression analysis. Principal component analysis condensed 16 landscape metrics into three factors: aggregation/diversity, dispersion/adjacency, and patchiness. The average annual total soil loss across all 62 analysed watersheds was estimated at 73.3 ± 78.2 (standard deviation) ton ha−1. A significant positive correlation was observed between landscape fragmentation and soil erosion, indicating that, as fragmentation increases, soil losses also increase. Furthermore, our analysis revealed a decreasing trend in soil loss rates in recent years, primarily attributed to the recovery of native vegetation since no significant soil management practices were widely implemented in the study area during the study period

    FORMAS ZOOARIALES EN EL DESARROLLO DE UNA COMUNIDAD DE BRIOZOOS

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    The dynamics of the relations between different zoarial forms of cheilostome bryozoans, during the development of a community on artificial substrates, have been studied along an infralittoral cliff of the northwestem Mediterranean Sea. Membraniporiform bryozoans (thick membraniporiform and thin membraniporiform zoarial types) prevail during the first stages of colonization. Later, at shallow depth, erect flexible forms (tuft-like zoarial type) tend to increase prevailing over the encrusting ones and, at greater depth, membraniporiform colonies continue to play a major role. The studied zoarial types show differences both in their ability to settle and to grow on bare and smooth surfaces and on substrate occupied by other organisms, and also to adjust to modifications of the substrate through time. The variations in the relative abundance of different zoarial forms correspond to changes in the availability of primary space and to new ecological conditions close to the substrate surface.Se ha estudiado la dinámica de las relaciones entre diversas formas zoariales de Briozoos Cheilostomata durante la evolución de una comunidad sobre sustrato artificial a lo largo de un acantilado infralitoral del Mediterráneo nord-occidental. Los briozoos membraniporiformes caracterizan las primeras fases de colonización. En seguida en las zonas más superficiales, las formas erectas y flexibles aumentan notablemente y tienden a prevalecer sobre las formas incrustantes. En las áreas más profundas en cambio, las colonias membraniporiformes siguen siendo predominantes. Los diversos tipos zoariales que se han considerado, presentan grandes diferencias por lo que respecta, ya sea a la capacidad de fijarse y crecer sobre superficies desnudas y lisas o sobre substratos ocupados por otros organismos, ya sea la posibilidad de adaptarse a las variaciones que sufre el substrato en el transcurso del tiempo. Las variaciones en la abundancia relativa de los diversos tipos morfológicos está correlacionada con la disminución del espacio primario y, por lo tanto, con las nuevas condiciones ecológicas a nivel de las supeficies del sustrato

    Unraveling the enigma of new-onset refractory status epilepticus: a systematic review of aetiologies

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    Background and purpose: New-onset refractory status epilepticus (NORSE) is a clinical presentation, neither a specific diagnosis nor a clinical entity. It refers to a patient without active epilepsy or other pre-existing relevant neurological disorder, with a NORSE without a clear acute or active structural, toxic or metabolic cause. This study reviews the currently available evidence about the aetiology of patients presenting with NORSE and NORSE-related conditions. Methods: A systematic search was carried out for clinical trials, observational studies, case series and case reports including patients who presented with NORSE, febrile-infection-related epilepsy syndrome or the infantile hemiconvulsion-hemiplegia and epilepsy syndrome. Results: Four hundred and fifty records were initially identified, of which 197 were included in the review. The selected studies were retrospective case–control (n = 11), case series (n = 83) and case reports (n = 103) and overall described 1334 patients both of paediatric and adult age. Aetiology remains unexplained in about half of the cases, representing the so-called ‘cryptogenic NORSE’. Amongst adult patients without cryptogenic NORSE, the most often identified cause is autoimmune encephalitis, either non-paraneoplastic or paraneoplastic. Infections are the prevalent aetiology of paediatric non-cryptogenic NORSE. Genetic and congenital disorders can have a causative role in NORSE, and toxic, vascular and degenerative conditions have also been described. Conclusions: Far from being a unitary condition, NORSE is a heterogeneous and clinically challenging presentation. The development and dissemination of protocols and guidelines to standardize diagnostic work-up and guide therapeutic approaches should be implemented. Global cooperation and multicentre research represent priorities to improve the understanding of NORSE

    Estado da Arte do Sensoriamento Remoto de Radar: Fundamentos, Sensores, Processamento de Imagens e Aplicações.

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    Este artigo aborda o estado da arte do sensoriamento remoto por radar e foi elaborado para fazer parte da edição especial de comemoração dos 50 anos desta revista. Neste estudo, é apresentada uma breve introdução sobre os fundamentos do sensoriamento remoto por radar, com destaque para os parâmetros mais importantes de imageamento e da superfície terrestre envolvidos no processo de obtenção de imagens de radar. Ênfase é dada para o comprimento de onda, polarização das ondas eletromagnéticas e geometria de obtenção de imagens (parâmetros de imageamento) e para a umidade de solos e da vegetação, rugosidade do terreno e estrutura da vegetação (parâmetros da superfície terrestre). Em seguida, são apresentados os principais sensores orbitais de radar de abertura sintética que estão atualmente em operação e os principais processamentos digitais de imagens de radar, destacando-se a conversão dos valores digitais para coeficientes de retroespalhamento, os filtros espaciais para redução do ruído speckle, as técnicas de decomposição de imagens e o processamento InSAR. Finalmente, é apresentada uma breve discussão sobre algumas aplicações potenciais, com especial atenção para o monitoramento de derrame de óleo em plataformas continentais, estimativa de biomassa aérea, monitoramento de desmatamento em coberturas florestais tropicais, detecção de áreas de plantio de arroz irrigado e estimativa de umidade de solos

    Pharmacotherapy for Dravet Syndrome: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

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    Background: Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy characterized by drug-resistant, lifelong seizures. The management of seizures in DS has changed in recent years with the approval of new antiseizure medications (ASMs). Objective: The aim of this study was to estimate the comparative efficacy and tolerability of the ASMs for the treatment of seizures associated with DS using a network meta-analysis (NMA). Methods: Studies were identified by conducting a systematic search (week 4, January 2023) of the MEDLINE (accessed by PubMed), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and US National Institutes of Health Clinical Trials Registry (http://www.clinicaltrials.gov) databases. Any randomized, controlled, double- or single-blinded, parallel-group study comparing at least one ASM therapy against placebo, another ASM, or a different dose of the same ASM in participants with a diagnosis of DS was identified. The efficacy outcomes were the proportions of participants with ≥ 50% (seizure response) and 100% reduction (seizure freedom) in baseline convulsive seizure frequency during the maintenance period. The tolerability outcomes included the proportions of patients who withdrew from treatment for any reason and who experienced at least one adverse event (AE). Effect sizes were estimated by network meta-analyses within a frequentist framework. Results: Eight placebo-controlled trials were included, and the active add-on treatments were stiripentol (n = 2), pharmaceutical-grade cannabidiol (n = 3), fenfluramine hydrochloride (n = 2), and soticlestat (n = 1). The studies recruited 680 participants, of whom 409 were randomized to active treatments (stiripentol = 33, pharmaceutical-grade cannabidiol = 228, fenfluramine hydrochloride = 122, and soticlestat = 26) and 271 to placebo. Pharmaceutical-grade cannabidiol was associated with a lower rate of seizure response than fenfluramine hydrochloride (odds ratio [OR] 0.20, 95% confidence interval [CI] 0.07–0.54), and stiripentol was associated with a higher seizure response rate than pharmaceutical-grade cannabidiol (OR 14.07, 95% CI 2.57–76.87). No statistically significant differences emerged across the different ASMs for the seizure freedom outcome. Stiripentol was associated with a lower probability of drug discontinuation for any reason than pharmaceutical-grade cannabidiol (OR 0.45, 95% CI 0.04–5.69), and pharmaceutical-grade cannabidiol was associated with a lower proportion of participants experiencing any AE than fenfluramine hydrochloride (OR 0.22, 95% CI 0.06–0.78). Stiripentol had a higher risk of AE occurrence than pharmaceutical-grade cannabidiol (OR 75.72, 95% CI 3.59–1598.58). The study found high-quality evidence of efficacy and tolerability of the four ASMs in the treatment of convulsive seizures in DS. Conclusions: There exists first-class evidence that documents the efficacy and tolerability of stiripentol, pharmaceutical-grade cannabidiol, fenfluramine hydrochloride, and soticlestat for the treatment of seizures associated with DS, and allows discussion about the expected outcomes regarding seizure frequency reduction and tolerability profiles

    Análise do hot spot do extrativismo do babaçu e atividades agropecuárias no Maranhão.

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    O extrativismo do babaçu (Attalea speciosa Mart ex. Spreng) ocorre devido ao aumento da densidade das palmeiras nas formações com diferentes estádios de sucessão natural e em meio ás pastagens, lavouras permanentes e temporárias, sejam consorciados ou não. Porém, as práticas agroflorestais vêm perdendo espaço para a agropecuária intensiva. O presente estudo tem por objetivo realizar a Análise Hot Spot do extrativismo babaçu e das atividades agropecuárias no Maranhão. Utilizou-se a ferramenta Hotspot Analysis disponível no software Arc GIS, a base cartográfica digital Malha Municipal Digital do Zoneamento do Estado do Maranhão e a criação de um banco de dados geográfico tendo por fonte o Sistema IBGE/SIDRA para verificar se essas atividades apresentam agrupamento com significância estatística. Os mapas produzidos mostram os temas regionalizados em localizações distintas no estado na forma de hot spots, os quais podem ser indicativos de polos produtivos e de mudanças tecnológicas na agropecuária e no extrativismo

    Dinâmica espaço-temporal da produção de amêndoas de babaçu e da utilização das terras no Maranhão.

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    O babaçu é uma palmeira nativa pioneira e o seu extrativismo se deve ao aumento de sua densidade em formações secundárias onde também são praticados sistemas de produção agropecuária associados às práticas agroflorestais pelas quebradeiras de cocos e pequenos agricultores em parcerias com os latifundiários. Essas associações de sistemas de produção vêm perdendo espaço para a agropecuária intensiva que envolve maior quantidade de insumos agropecuários e mecanização tendo por consequência a diminuição da regeneração natural das palmeiras de babaçu. O presente estudo buscou entender melhor a dinâmica espaço-temporal da produção de amêndoas de babaçu e das atividades de uso do solo no Maranhão entre 1990 e 2011, utilizando análise Hot Spot. Os resultados desta análise indicam tendências de concentração espacial das atividades de uso do solo no Maranhão, variando ao longo do período de análise. No caso do extrativismo do babaçu, identificou-se um cold spot sugerindo influências diretas de outras formas de utilização das terras sobre esta atividade de produção

    Geomorphological and bioclimatic relationships in the occurrence of species of agro-extractivist interest in the Cerrado biome.

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    The distribution of species of agro-extractivist interest and their ecological relationship with the physical environment geomorphological and bioclimatic allow supporting strategies aimed at socioeconomic and environmental development. We evaluated the contribution of high spatial resolution topographic variables in ecological niche models and the relationship of the distribution of five tree species with the geomorphological units and bioclimatic variables. The variables related to temperature variation and water availability proved to be important in predicting the areas of occurrence of the target species, with increased suitability of occurrence in regions with higher isothermality, located in the plateau and table geomorphological units. The predictions showed a significant difference when high spatial resolution variables were used, generating a more conservative scenario in the indication of suitable regions for the occurrence of species, important for local scale studies. The geomorphological units of plateau and tableland showed high suitability of occurrence, while the fluvial plains and dissected depressions did not present suitability for the occurrence of the species. The results allow us to strategically define areas with the greatest productive potential and prioritize areas for conservation, management, ecological restoration of forests, and targeting areas for the implementation of community agro-industries, essential for territorial planning within traditional communities

    Pre-natal and post-natal exposure to respiratory infection and atopic diseases development: a historical cohort study

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    BACKGROUND: According to the hygiene hypothesis, infections in early life protect from allergic diseases. However, in earlier studies surrogate measures of infection rather than clinical infections were associated with decreased frequencies of atopic diseases. Exposure to infection indicating sub-clinical infection rather than clinical infection might protect from atopic diseases. Objective: to investigate whether exposure to acute respiratory infections within pregnancy and the first year of life is associated with atopic conditions at age 5–14 years and to explore when within pregnancy and the first year of life this exposure is most likely to be protective. METHODS: Historical cohort study: Population level data on acute respiratory infections from the routine reporting system of the former German Democratic Republic were linked with individual data from consecutive surveys on atopic diseases in the same region (n = 4672). Statistical analyses included multivariate logistic regression analysis and polynomial distributed lag models. RESULTS: High exposure to acute respiratory infection between pregnancy and age one year was associated with overall reduced odds of asthma, eczema, hay fever, atopic sensitization and total IgE. Exposure in the first 9 months of life showed the most pronounced effect. Adjusted odds ratio's for asthma, hay fever, inhalant sensitization and total IgE were statistical significantly reduced up to around half. CONCLUSION: Exposure to respiratory infection (most likely indicating sub-clinical infection) within pregnancy and the first year of life may be protective in atopic diseases development. The post-natal period thereby seems to be particularly important
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