883 research outputs found

    Plankton studies in a mangrove environment II: the standing stock and some ecological factors

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    This work was undertaken to obtain information on seasonal variation of the plankton communities of the Cananéia mangrove system. The results provide a background for further investigations on primary and secondary productivity and the study of the interrelationships of ecological factors that affect the distribution and abundance of plankton. The correlation of data obtained shows that in the mangrove system under study there are different environments with distinct species.Durante 1962, em janeiro, abril, julho e outubro, foram feitas coletas em quatro estações oceanográficas, três na região lagunar de Cananéia e uma na região costeira. O objetivo foi o de efetuar um primeiro levantamento do bacterio, fito e zooplâncton, assim como estudar os fatores ecológicos atuantes nos diferentes locais, em diferentes épocas do ano. Amostras foram tomadas durante os períodos de maré alta e baixa, em superfície e profundidade, para determinação do plancton, material em suspensão, salinidade e oxigênio. Pelos resultados obtidos, verificou-se que o "standing stock" diminuiu gradualmente da estação I para a estação IV, mostrando uma correlação inversa com a salinidade. As condições extremamente variáveis da região lagunar constituem um fator seletivo para as diferentes espécies planctônicas. No fitoplâncton foram encontrados: Diatomáceas, Dinoflagelados, Silicoflagelados, Fitoflagelados e Cianofíceas. As Diatomáceas sempre predominaram, exceto na estação I, no mês de abril, quando apareceram os Fitoflagelados em proporções superiores. O máximo de organismos do fitoplâncton foi na estação I, em janeiro, havendo um decréscimo durante os meses de abril e julho e um novo aumento em outubro. O zooplâncton, constituído, predominantemente, por copépodos e estágios larvares, apresentou também Moluscos, Tintinoideos e em pequenas proporções Medusas, Chaetognatos e Cladoceros. O máximo de zooplâncton ocorreu em abril em todas as estações. A quantidade de matéria orgânica em suspensão, apresentou altos índices, nas estações lagunares em comparação com a costeira, isto devido a detritos levados pelos rios que circundam a região, ao plancton e à decomposição in situ da vegetação do mangue. Por outro lado, a matéria em suspensão, a concentração do plancton e as substâncias coloridas provenientes da vegetação do mangue, mostraram bastante influência sobre a transparência e coloração da água, diminuindo a extensão da camada eufótica

    Palliative care and Parkinson's disease : meeting summary and recommendations for clinical research

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    Introduction: Palliative care is an approach to caring for patients and families affected by serious illnesses that focuses on the relief of suffering through the management of medical symptoms, psychosocial issues, advance care planning and spiritual wellbeing. Over the past decade there has been an emerging clinical and research interest in the application of palliative care approaches to Parkinson’s disease (PD) and outpatient palliative care services are now offered by several movement disorders centers. Methods: An International Working Group Meeting on PD and Palliative Care supported by the Parkinson’s Disease Foundation was held in October 2015 to review the current state of the evidence and to make recommendations for clinical research and practice. Results: Topics included: 1) Defining palliative care for PD; 2) Lessons from palliative care for heart failure and other chronic illnesses; 3) Patient and caregiver Needs; 4) Needs assessment tools; 5) Intervention strategies; 6) Predicting prognosis and hospice referrals; 7) Choice of appropriate outcome measures; 8) Implementation, dissemination and education research; and 9) Need for research collaborations. We provide an overview of these discussions, summarize current evidence and practices, highlight gaps in our knowledge and make recommendations for future research. Conclusions: Palliative Care for PD is a rapidly growing area which holds great promise for improving outcomes for PD patients and their caregivers. While clinical research in this area can build from lessons learned in other diseases, there is a need for observational, methodological and interventional research to address the unique needs of PD patients and caregivers

    A continuous time random walk model for financial distributions

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    We apply the formalism of the continuous time random walk to the study of financial data. The entire distribution of prices can be obtained once two auxiliary densities are known. These are the probability densities for the pausing time between successive jumps and the corresponding probability density for the magnitude of a jump. We have applied the formalism to data on the US dollar/Deutsche Mark future exchange, finding good agreement between theory and the observed data.Comment: 14 pages, 5 figures, revtex4, submitted for publicatio

    A Uniform CO Survey of the Molecular Clouds in Orion and Monoceros

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    We report the results of a new large scale survey of the Orion-Monoceros complex of molecular clouds made in the J = 1->0 line of CO with the Harvard-Smithsonian 1.2m millimetre-wave telescope. The survey consists of 52,288 uniformly spaced spectra that cover an area of 432 square degrees on the sky and is the most sensitive large-scale survey of the region to date. Distances to the constituent molecular clouds of the complex, estimated from an analysis of foreground and background stars, have provided information on the three dimensional structure of the entire complex.Comment: Accepted for publication in Astronomy and Astrophysics. 19 pages with 17 colour figures - 39 if you count the sub-figures separately. The figures here have been bit-mapped with some loss of quality and beauty. The paper version in A&A will be in greyscale with the on-line version in colour. In the meantime the colour version can be obtained by following links at http://www.star.bris.ac.uk/mrwm . The 9MB PostScript is recommended if you have appropriate bandwidth or otherwise the 2.3MB PDF is usabl

    Self-similar motion for modeling anomalous diffusion and nonextensive statistical distributions

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    We introduce a new universality class of one-dimensional iteration model giving rise to self-similar motion, in which the Feigenbaum constants are generalized as self-similar rates and can be predetermined. The curves of the mean-square displacement versus time generated here show that the motion is a kind of anomalous diffusion with the diffusion coefficient depending on the self-similar rates. In addition, it is found that the distribution of displacement agrees to a reliable precision with the q-Gaussian type distribution in some cases and bimodal distribution in some other cases. The results obtained show that the self-similar motion may be used to describe the anomalous diffusion and nonextensive statistical distributions.Comment: 15pages, 5figure

    Results of the ESO-SEST Key Programme on CO in the Magellanic Clouds. IX. The giant LMC HII region complex N11

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    We present maps and a catalogue containing the J=1-0 12CO parameters of 29 individual molecular clouds in the second-brightest LMC star formation complex, N11. In the southwestern part of N11, molecular clouds occur in a ring or shell surrounding the major OB star association LH9. In the northeastern part, a chain of molecular clouds delineates the rim of one of the so-called supergiant shells in the LMC. The well-defined clouds have dimensions close to those of the survey beam (diameters of 25 pc or less). Some of the clouds were also observed in J=2-1 12CO, and in the lower two transitions of 13CO. Clouds mapped with a twice higher angular resolution in J=2-1 12CO show substructure with dimensions once again comparable to those of the mapping beam. The few clouds for which we could model physical parameters have fairly warm (T(kin) = 60 - 150 K) and moderately dense (n(H2) = 3000 cm-3) gas. The northeastern chain of CO clouds, although lacking in diffuse intercloud emission, is characteristic of the more quiescent regions of the LMC and appears to have been subject to relatively little photo-processing. The clouds forming part of the southwestern shell or ring, however, are almost devoid of diffuse intercloud emission and also exhibit other characteristics of an extreme photon-dominated region (PDR).Comment: 14 pages; accepted for publication in A&

    Evaluation of a corticotropin releasing hormone type 1 receptor antagonist in women with posttraumatic stress disorder: study protocol for a randomized controlled trial

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    Background: Pharmacologic treatment options for posttraumatic stress disorder (PTSD) are limited in number and effectiveness. Medications currently in use to treat PTSD were originally approved based on their efficacy in other disorders, such as major depression. Substantial research in PTSD suggests that increased activity of corticotropin releasing hormone (CRH)-containing circuits are involved in the pathophysiology of the disease. This Phase II trial aims to evaluate the efficacy of a CRH type 1 receptor (CRHR1) antagonist in the treatment of PTSD. Methods/design: Currently untreated adult women, ages 18 to 65 years, with a primary psychiatric diagnosis of PTSD of at least 3 months' duration, are being enrolled in a parallel-group, double-blind, placebo-controlled, randomized clinical trial evaluating the efficacy and safety of GSK561679, a novel CRHR1 receptor antagonist. GSK561679 (or matching placebo) is prescribed at a fixed dose of 350 mg nightly for six weeks. The primary trial hypothesis is that GSK561679 will reduce symptoms of PTSD, as measured by the Clinician-Administered PTSD Scale (CAPS), significantly more than placebo after six weeks of treatment. Putative biological markers of PTSD which may influence treatment response are measured prior to randomization and after five weeks' exposure to the study medication, including: fear conditioning and extinction using psychophysiological measures; variants of stress-related genes and gene expression profiles; and indices of HPA axis reactivity. In addition, the impact of PTSD and treatment on neuropsychological performance and functional capacity are assessed at baseline and after the fifth week of study medication. After completion of the six-week double blind treatment period, subjects enter a one-month follow-up period to monitor for sustained response and resolution of any adverse effects. Discussion: Considerable preclinical and human research supports the hypothesis that alterations in central nervous system CRH neuronal activity are a potential mediator of PTSD symptoms. This study is the first to assess the efficacy of a specific antagonist of a CRH receptor in the treatment of PTSD. Furthermore, the biological and neuropsychological measures included in this trial will substantially inform our understanding of the mechanisms of PTSD

    Topological Orthoalgebras

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    We define topological orthoalgebras (TOAs) and study their properties. While every topological orthomodular lattice is a TOA, the lattice of projections of a Hilbert space is an example of a lattice-ordered TOA that is not a toplogical lattice. On the other hand, we show that every compact Boolean TOA is a topological Boolean algebra. We also show that a compact TOA in which 0 is an isolated point is atomic and of finite height. We identify and study a particularly tractable class of TOAs, which we call {\em stably ordered}: those in which the upper-set generated by an open set is open. This includes all topological OMLs, and also the projection lattices of Hilbert spaces. Finally, we obtain a topological version of the Foulis-Randall representation theory for stably ordered TOAsComment: 16 pp, LaTex. Minor changes and corrections in sections 1; more substantial corrections in section

    Exact Tagged Particle Correlations in the Random Average Process

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    We study analytically the correlations between the positions of tagged particles in the random average process, an interacting particle system in one dimension. We show that in the steady state the mean squared auto-fluctuation of a tracer particle grows subdiffusively as sigma2(t) t1/2sigma^2(t) ~ t^{1/2} for large time t in the absence of external bias, but grows diffusively sigma2(t) tsigma^2(t) ~ t in the presence of a nonzero bias. The prefactors of the subdiffusive and diffusive growths as well as the universal scaling function describing the crossover between them are computed exactly. We also compute sigmar2(t)sigma_r^2(t), the mean squared fluctuation in the position difference of two tagged particles separated by a fixed tag shift r in the steady state and show that the external bias has a dramatic effect in the time dependence of sigmar2(t)sigma_r^2(t). For fixed r, sigmar2(t)sigma_r^2(t) increases monotonically with t in absence of bias but has a non-monotonic dependence on t in presence of bias. Similarities and differences with the simple exclusion process are also discussed.Comment: 10 pages, 2 figures, revte
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