2,438 research outputs found

    Restauração ecológica em campos invadidos por Urochloa decubens nos campos sulinos

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    Ecossistemas campestres encontram-se fortemente impactados por conversão de hábitat e por espécies exóticas invasoras. É necessário restaurar os ecossistemas campestres ao redor do globo. Entretanto, para os ecossistemas campestres brasileiros há poucas experiências de restauração e precisamos testar a viabilidade de técnicas normalmente empregadas em outros lugares. O objetivo deste estudo foi testar diferentes combinações de técnicas para restauração de campos invadidos por Urochloa decumbens nos Campos Sulinos, sul do Brasil. Combinaram-se duas técnicas de controle da espécie invasora (aplicação de herbicida e remoção superficial de solo) e duas técnicas de introdução de espécies nativas (transposição de feno e semeadura direta). Foram estabelecidos oito blocos em um experimento bifatorial no Morro Santana, Porto Alegre, combinando dois fatores e cada um com três tratamentos (duas técnicas mais o controle). A cobertura de vários grupos de espécies, riqueza de espécies e composição de espécies foram avaliadas por análises de variância, e então também por análise de coordenadas principais. Adicionalmente, a relação entre a cobertura da invasora e das espécies nativas foi investigada. As técnicas de controle da invasora mostraram-se eficientes tanto na redução da cobertura da espécie, como em permitir a entrada de espécies nativas na comunidade. Comparando as duas técnicas, aplicação de herbicida pareceu ser melhor do que a remoção superficial de solo, pois parcelas que tiveram a aplicação tiveram menor cobertura da invasora e maior riqueza de espécies. Já as técnicas de introdução de espécies mostraram-se insuficientes para adicionar espécies nativas na comunidade para competir com U. decumbens. Padrões de composição de espécies diferiram entre os tratamentos. Técnicas de controle do invasor diferiram grandemente do seu controle, que foi dominado por U. decumbens. Uma clara relação existe entre a cobertura da invasora e a presença e cobertura de espécies nativas. Então o controle da espécie invasora é fundamental para uma maior recuperação da vegetação. Entretanto, os resultados aqui apresentados correspondem a apenas oito meses após a finalização da implementação do experimento, e ações futuras de manejo na área deverão combinar novamente o controle da invasora com introdução de espécies nativas.Grasslands ecosystems are strongly impacted by land use and invasive species. It is necessary restore these ecosystems around the world. However, there are few experiences with ecological restoration for the Brazilian grasslands and we need to test the viability of techniques normally used in others grasslands ecosystems. The aim of this study was to test different combinations of techniques to the ecological restoration of grasslands invaded by Urochloa decumbens in Campos, Southern Brazil. We combine two techniques to control the invasive species (herbicide application and topsoil removal) and two techniques to introduce native species (hay transfer and direct sowing). We established nine blocks in a bi-factorial experiment on Morro Santana, Porto Alegre, Rio Grande do Sul, combining two factors and each one with three treatments (two techniques plus the control). The coverage of various groups of species, species richness, and species composition were evaluated by variance analyses, and the later also by a principal ordination analysis. Additionally, the relation between invader coverage and native species was investigated. Both techniques to control invasive species have shown to be efficient to reduce the coverage of the invasive species, as well as to allow the arrival of native species. Specifically comparing them, the herbicide application seems to be a better treatment than the topsoil removal, once plots with herbicide had lower invasive species coverage and higher species richness. However, the species introduction techniques failed efficiently to add native species to the community composition and to compete with U. decumbens. Species composition patterns differed among the treatments. The invader control techniques greatly differed from their control, which was dominated by U. decumbens. A clear relationship exists between the invader coverage and the presence and coverage of native species. Thus, the control of the invasive species is fundamental to further vegetation recovery. Nevertheless, results here presented correspond to just eight months from the experiment implantation and future monitoring and management actions on the area should combine once more the control of the invasive species and the introduction of native species

    THE IMPORTANCE OF CREATING A CONSERVATION UNIT IN MORRO GAÚCHO, CITIES OF ARROIO DO MEIO AND CAPITÃO/RS

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    Conservation Units (CUs) are geographically areas defined management processes linked to its territory, having as main objective the protection of long-term environmental attributes in situ. Therefore aims to highlight the importance of creating a UC in Morro Gaucho, natural heritage of the cities of the Arroio do Meio and Capitão, Rio Grande do Sul, from the identification of environmental impacts that threaten its biodiversity and landscape. Thus, the work occurred from field trips, reading research already conducted in the area and local newspapers and attending meetings of a local nongovernmental organization. The environmental impacts were recognized the occurrence of invasive species, tourism and the irregular presence of a unit transshipment of solid waste, among others, with the consequences when the assault on local biodiversity. The importance of creating a UC on site is also highlighted by the presence of the Biosphere Reserve and the percentages of the Atlantic Forest remnants in the areas of the municipalities. Therefore, the establishment of a protected area in Morro Gaúcho aims to ensure the conservation from a concrete action to protect nature and its management processes and management bound.Unidades de Conservação (UCs) são áreas definidas geograficamente vinculadas a processos de gestão de seu território, tendo como objetivo principal a proteção ao longo prazo dos atributos ambientais in situ. Assim, visa-se destacar a importância da criação de uma UC no Morro Gaúcho, patrimônio natural dos municípios de Arroio do Meio e Capitão, Rio Grande do Sul, a partir da identificação dos impactos ambientais que ameaçam a sua biodiversidade e paisagem. Desta forma, o trabalho ocorreu a partir de saídas de campo, leitura de pesquisas já realizadas na área e jornais locais e a participação em reuniões de uma organização não-governamental local. Os impactos ambientais reconhecidos foram a ocorrência de espécies exóticas invasoras, o turismo irregular e a presença de uma unidade de transbordo de resíduos sólidos, entre outros, tendo como consequências as agressões à biodiversidade local. A importância da criação de uma UC no local também é destacada pela presença da Reserva da Biosfera e os percentuais de remanescentes de Mata Atlântica nas áreas dos municípios. Portanto, a instituição de uma área protegida no Morro Gaúcho visa garantir a conservação a partir de uma ação concreta de proteção à natureza e seus processos de manejo e gestão vinculados

    Performance of the Titanium-Nitride-Oxide Coated Stent in Patients with Multivessel Coronary Artery Disease

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    ABSTRACTBackgroundTo date, there are no studies evaluating the use of the titanium-nitride-oxide coated stent in patients with multivessel coronary artery disease. We have compared the performance of the Titan-2® stent to that of the second generation drug-eluting stents in this scenario.MethodsFrom 2011 to 2012, 284 patients were treated with the Titan-2® stent, of which 100 (35.2%) had multivessel coronary artery disease. This group was compared to 100 patients, of a group of 304 (38.9%) patients with multivessel coronary artery disease treated with second generation drug-eluting stents with durable or biodegradable polymers. The primary endpoint was the occurrence of major adverse cardiovascular events at 1 year.ResultsClinical, angiographic and procedure-related characteristics of the patients did not show differences between groups. Most patients in the Titan-2® group were male (70%), mean age was 68.4 ± 12.9 years and 25% were diabetic. Stable symptomatic patients were prevalent (68%), 51% had three-vessel disease and ventricular function was preserved (55.6 ± 12.7%). The incidence of major adverse cardiovascular events at 1 year in the Titan-2® group was 21% (vs. 17%; p = 0.59), death was observed in 3% (vs. 2%; p > 0.99) of the patients, acute myocardial infarction in 5% (vs. 4%; p > 0.99) and a new revascularization procedure in 13% (vs. 11%; p = 0.83). Definitive stent thrombosis was not observed in either group.ConclusionsThe Titan-2® stent showed similar results to those of the second-generation drug-eluting stents, which makes it attractive for use in the complex scenario of patients with multivessel coronary artery disease.RESUMODesempenho do Stent Recoberto por Titânio-Óxido Nítrico em Pacientes com Doença Coronária MultiarterialIntrodçãoAté o momento, nenhum estudo avaliou o stent recoberto por titânio-óxido nítrico em pacientes com doença arterial coronariana multiarterial. Comparamos o desempenho do stent Titan-2® ao stents farmacológicos de segunda geragao nesse cenário.MétodosNo período de 2011 a 2012, 284 pacientes foram tratados com o stent Titan-2®, dos quais 100 (35,2%) eram portadores de doença arterial coronariana multiarterial. Esse grupo foi comparado a 100 pacientes, de um grupo de 304 (38,9%), com doença arterial coronariana multiarterial, tratados com o stent farmacológico de segunda geração com polímeros duráveis ou biodegradáveis. O desfecho primário foi a ocorrência de eventos cardíacos adversos maiores em 1 ano.ResultadosCaracterísticas clínicas, angiográficas e do procedimento não apresentaram diferenças entre os grupos. A maioria dos pacientes do grupo Titan-2® era do sexo masculino (70%), com idade de 68,4 ± 12,9 anos e 25% eram diabéticos. Predominaram os quadros clínicos estáveis (68%), 51% tinham acometimento triarterial e a função ventricular estava preservada. A incidência de eventos cardiovasculares adversos maiores em 1 ano no grupo Titan-2® foi de 21% (vs. 17%; p = 0,59), óbito ocorreu em 3% (vs. 2%; p > 0,99) dos pacientes, infarto do miocárdio em 5% (vs. 4%; p > 0,99) e nova revascularização miocárdica em 13% (vs. 11%; p = 0,83). Não foram constatadas tromboses de stent definitivas em nenhum grupo.ConclusõesO uso do Titan-2® apresentou resultados similares aos do stent farmacológico de segunda geração, o que o torna atrativo para ser utilizado no complexo cenário de pacientes portadores de doença arterial coronariana multiarterial

    Control and systems software for the Cosmology Large Angular Scale Surveyor (CLASS)

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    The Cosmology Large Angular Scale Surveyor (CLASS) is an array of polarization-sensitive millimeter wave telescopes that observes ~70% of the sky at frequency bands centered near 40GHz, 90GHz, 150GHz, and 220GHz from the Atacama desert of northern Chile. Here, we describe the architecture of the software used to control the telescopes, acquire data from the various instruments, schedule observations, monitor the status of the instruments and observations, create archival data packages, and transfer data packages to North America for analysis. The computer and network architecture of the CLASS observing site is also briefly discussed. This software and architecture has been in use since 2016, operating the telescopes day and night throughout the year, and has proven successful in fulfilling its design goals.Comment: 19 pages, 8 figures, to appear in Proc. SPI

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file
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