336 research outputs found

    Ocorrencia e abundância de espécies de plantas ameaçadas de extinção no entorno do reservatório da UHE Barra Grande.

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    Modelos de ocorrência e abundância de espécies são ferramentas atuais que devem ser incorporadas na conservação da biodiversidade no entorno de reservatórios de usinas hidroelétricas, prevendo ou planejando ações necessárias para mitigar os impactos ambientais destes empreendimentos. Neste estudo, nossos objetivos foram: modelar a ocorrência e abundância de espécies de plantas ameaçadas de extinção, verificar a relação entre a ocorrência prevista e a abundância observada e avaliar se os modelos baseados em abundância são mais eficientes em predizer a ocorrência do que aqueles baseados em dados de ocorrência (0/1). Representantes individuais de nove espécies (Araucaria angustifolia (Bertol.) Kuntze (Araucariaceae), Butia eriospatha (Mart. ex Drude) Becc. (Arecaceae), Clethra scabra Pers. (Clethraceae), Dicksonia sellowiana (Presl.) Hook. (Dicksoniaceae), Erythrina falcata Benth. (Fabaceae), Maytenus ilicifolia (Schrad.) Planch. (Celastraceae), Myrocarpus frondosus Allemão (Fabaceae), Podocarpus lambertii Klotzsch ex Endl. (Podocarpaceae) e Trithrinax brasiliensis Mart (Arecaceae)) foram contados em 388 parcelas (10x50m) aleatoriamente alocadas e georreferenciadas no entorno do reservatório da UHE Barra Grande (SC/RS). Modelamos sua relação com 15 variáveis ambientais utilizando dados de ocorrência (GLM) e abundância (Modelos Hurdle e Zero-inflado). Em geral, os modelos de ocorrência foram mais precisos do que os modelos de abundância. Para todas as espécies, a abundância observada foi correlacionada com a probabilidade de ocorrência, sugerindo que estudos futuros poderiam utilizar esta informação, em vez da abundância. Reconstruir padrões de abundância e de ocorrência é uma importante ferramenta para o planejamento de ações de conservação e manejo de espécies ameaçadas, permitindo que sejam indicadas as melhores áreas para a coleta e reintrodução de germoplasma vegetal ou mesmo a escolha de áreas de conservação com maior probabilidade de manter populações viáveis

    Stochastic analysis of surface roughness

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    For the characterization of surface height profiles we present a new stochastic approach which is based on the theory of Markov processes. With this analysis we achieve a characterization of the complexity of the surface roughness by means of a Fokker-Planck or Langevin equation, providing the complete stochastic information of multiscale joint probabilities. The method was applied to different road surface profiles which were measured with high resolution. Evidence of Markov properties is shown. Estimations for the parameters of the Fokker-Planck equation are based on pure, parameter free data analysis

    Acianthera hygrophila (Orchidaceae), nuevo registro para Uruguay

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    The epiphytic orchid Acianthera hygrophila (Barb. Rodr.) Pridgeon & M.W. Chase is reported for the first time for the flora of Uruguay. This species was found in a riverside forest of the Río Yaguarón in the East of Cerro Largo Department, near the border with Brazil. This record marks the Southern limit of distribution of the species. A description, an illustration and a distribution map of A. hygrophila are provided, as well as an identification key for Aciantheraspecies found in UruguaySe reporta por primera vez para la flora de Uruguay la orquídea epífita Acianthera hygrophila (Barb. Rodr.) Pridgeon & M.W. Chase. La misma fue hallada en el bosque ribereño del Río Yaguarón en el este del departamento de Cerro Largo próximo al límite con Brasil. Este registro representa el límite sur de distribución de la especie. Se presenta una descripción ampliada, ilustración y mapa de distribución de A. hygrophila, así como una clave para la identificación de las especies de Acianthera presentes en Urugua

    An orifice shape-based reduced order model of patient-specific mitral valve regurgitation

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    Mitral valve regurgitation (MR) is one of the most prevalent valvular heart diseases. Its quantitative assessment is challenging but crucial for treatment decisions. Using computational fluid dynamics (CFD), we developed a reduced order model (ROM) describing the relationship between MR flow rates, transvalvular pressure differences, and the size and shape of the regurgitant valve orifice. Due to its low computational cost, this ROM could easily be implemented into clinical workflows to support the assessment of MR. We reconstructed mitral valves of 43 patients from 3D transesophageal echocardiographic images and estimated the 3D anatomic regurgitant orifice areas using a shrink-wrap algorithm. The orifice shapes were quantified with three dimensionless shape parameters. Steady-state CFD simulations in the reconstructed mitral valves were performed to analyse the relationship between the regurgitant orifice geometry and the regurgitant hemodynamics. Based on the results, three ROMs with increasing complexity were defined, all of which revealed very good agreement with CFD results with a mean bias below 3% for the MR flow rate. Classifying orifices into two shape groups and assigning group-specific flow coefficients in the ROM reduced the limit of agreement predicting regurgitant volumes from 9.0 ml to 5.7 ml at a mean regurgitant volume of 57 ml

    Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

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    The single-pion production reactions ppdπ+pp\to d\pi^+, ppnpπ+pp\to np\pi^+ and ppppπ0pp\to pp\pi^0 were measured at a beam momentum of 0.95 GeV/c (TpT_p \approx 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the npπ+np\pi^+ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the ppπ0pp\pi^0 channel we find in the npπ+np\pi^+ channel a strong influence of the Δ\Delta excitation already at this energy close to threshold. In particular we find a (3cos2Θ+1)(3 cos^2\Theta + 1) dependence in the pion angular distribution, typical for a pure s-channel Δ\Delta excitation and identical to that observed in the dπ+d\pi^+ channel. Since the latter is understood by a s-channel resonance in the 1D2^1D_2 pnpn partial wave, we discuss an analogous scenario for the pnπ+pn\pi^+ channel

    Dexamethasone to prevent everolimus-induced stomatitis (Alliance MIST trial: A221701)

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    mTOR inhibitors such as everolimus may cause oral stomatitis, often a dose-limiting toxicity. Prior clinical research has suggested that a dexamethasone mouth rinse might help prevent and/or treat this. Alliance A221701 was a randomized phase III trial of patients initiating 10 mg daily oral everolimus that compared dexamethasone mouthwash taken preventively (initial dexamethasone group) versus therapeutically (initial placebo group) to assess two coprimary endpoints: the incidence of mTOR inhibitor-associated stomatitis (mIAS), and the area under the curve (AUC) of mIAS-associated pain over an 8-week treatment period. A Fisher\u27s exact test was used to compare the incidences while a Wilcoxon rank-sum test was used to compare the AUCs. In addition, we performed an exploratory analysis of the association of everolimus trough concentrations and toxicity using a Mann-Whitney U test. Due to slow accrual, this study closed after 39 patients were randomized (19 to upfront placebo and 20 to upfront dexamethasone). There were no significant differences between groups seen in either of the coprimary endpoints; furthermore, we found no association between whole blood everolimus trough concentrations and toxicity. Although limited by poor enrollment, the results of this study do not suggest that prophylactic dexamethasone mouthwash is superior to therapeutic dexamethasone mouthwash (initiated at the first sign of mouth pain) for reducing the incidence or severity of mIAS from everolimus

    A “Soft” Approach to Analysing Mobile Financial Services Sociotechnical Systems

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    Advances in mobile computing have presented a huge opportunity to provide Mobile Financial Services (MFS) to half of the world’s population who currently do not have access to financial services. However, cybersecurity concerns in the mobile computing ecosystem have slowed down the adoption of MFS. The adoption of MFS is further hampered by the lack of a clear understanding of the interaction between the complex infrastructures and human factors that exist in the ecosystem for Mobile Financial Services Socio-Technical Systems (MFSSTS). This paper presents the work in progress of investigating the problem of MFSSTS. It discusses the preliminary results and understanding obtained from using Human Factor approaches to build and analyse the model for MFSSTS
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