201 research outputs found

    MCMC Bayesian Estimation in FIEGARCH Models

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    Bayesian inference for fractionally integrated exponential generalized autoregressive conditional heteroskedastic (FIEGARCH) models using Markov Chain Monte Carlo (MCMC) methods is described. A simulation study is presented to access the performance of the procedure, under the presence of long-memory in the volatility. Samples from FIEGARCH processes are obtained upon considering the generalized error distribution (GED) for the innovation process. Different values for the tail-thickness parameter \nu are considered covering both scenarios, innovation processes with lighter (\nu2) tails than the Gaussian distribution (\nu=2). A sensitivity analysis is performed by considering different prior density functions and by integrating (or not) the knowledge on the true parameter values to select the hyperparameter values

    Unified topological characterization of electronic states in spin textures from noncommutative K-theory

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    The nontrivial topology of spin systems such as skyrmions in real space can promote complex electronic states. Here, we provide a general viewpoint at the emergence of topological electronic states in spin systems based on the methods of noncommutative K-theory. By realizing that the structure of the observable algebra of spin textures is determined by the algebraic properties of the noncommutative hypertorus, we arrive at a unified understanding of topological electronic states which we predict to arise in various noncollinear setups. The power of our approach lies in an ability to categorize emergent topological states algebraically without referring to smooth real- or reciprocal-space quantities. This opens a way towards an educated design of topological phases in aperiodic, disordered, or non-smooth textures of spins and charges containing topological defects.Comment: 5 pages, 2 figure

    Trends of mortality due to oral and oropharyngeal cancers in Uruguay from 1997 to 2014

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    To analyze the trends of oral and oropharyngeal cancer mortality in Uruguay between 1997 and 2014 according to sex and age groups and its possible association with sociodemographic factors. A time-series ecological study using secondary data was performed. The data about mortality due to oral and oropharyngeal cancers were obtained from the Statistics Vitals Department of the Public Health Ministry of Uruguay. To estimate the mortality trends of the historical series, by sex, anatomical site and age groups, linear regressions generated by the Prais-Winsten procedure were used. The analysis of mortality trends for oral cavity and oropharyngeal cancers in Uruguay indicated that the global mortality rate was stable over the studied period. The women's mortality rate increased from 0.51 per 100,000 in 1997 to 0.65 per 100,000 in 2014 while for men, rates per 100,000 went from 3.22 in 1997 to 2.20 per 100,000 in 2014. Mortality from oral cancer in men decreased between 1997 and 2014. Mortality by oropharyngeal cancer, irrespective of sex, remained stable. Analysis by cancer site revealed decreasing trends tumors situated in the base of the tongue and gum. Years of education, unemployment, smoking and Gini index were not associated with mortality trends. The overall mortality from oral and oropharyngeal cancer in Uruguay has remained constant in the period between 1997 and 2014. Oral cancer mortality decreased in men and increased in women and decreased at the base of the tongue. It?s necessary to continue monitoring the behavior of these diseases

    Identfication and quantfication of giant bioaerosol particles over the Amazon rainforest

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    Eukarya dominate the coarse primary biological aerosol (PBA) above the Amazon rainforest canopy, but their vertical profile and seasonality is currently unknown. In this study, the stratification of coarse and giant PBA >5 µm were analyzed from the canopy to 300 m height at the Amazon Tall Tower Observatory in Brazil during the wet and dry seasons. We show that >2/3 of the coarse PBA were canopy debris, fungal spores commonly found on decaying matter were second most abundant (ranging from 15 to 41%), followed by pollens (up to 5%). The atmospheric roughness layer right above the canopy had the greatest giant PBA abundance. Measurements over 5 years showed an increased abundance of PBA during a low-rainfall period. Giant particles, such as pollen, are reduced at 300 m, suggesting their limited dispersal. These results give insights into the giant PBA emissions of this tropical rainforest, and present a major step in understanding the type of emitted particles and their vertical distribution

    Preventive Antibacterial Therapy in Acute Ischemic Stroke: A Randomized Controlled Trial

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    BACKGROUND: Pneumonia is a major risk factor of death after acute stroke. In a mouse model, preventive antibacterial therapy with moxifloxacin not only prevents the development of post-stroke infections, it also reduces mortality, and improves neurological outcome significantly. In this study we investigate whether this approach is effective in stroke patients. METHODS: Preventive ANtibacterial THERapy in acute Ischemic Stroke (PANTHERIS) is a randomized, double-blind, placebo-controlled trial in 80 patients with severe, non-lacunar, ischemic stroke (NIHSS>11) in the middle cerebral artery (MCA) territory. Patients received either intravenous moxifloxacin (400 mg daily) or placebo for 5 days starting within 36 hours after stroke onset. Primary endpoint was infection within 11 days. Secondary endpoints included neurological outcome, survival, development of stroke-induced immunodepression, and induction of bacterial resistance. FINDINGS: On intention-to treat analysis (79 patients), the infection rate at day 11 in the moxifloxacin treated group was 15.4% compared to 32.5% in the placebo treated group (p = 0.114). On per protocol analysis (n = 66), moxifloxacin significantly reduced infection rate from 41.9% to 17.1% (p = 0.032). Stroke associated infections were associated with a lower survival rate. In this study, neurological outcome and survival were not significantly influenced by treatment with moxifloxacin. Frequency of fluoroquinolone resistance in both treatment groups did not differ. On logistic regression analysis, treatment arm as well as the interaction between treatment arm and monocytic HLA-DR expression (a marker for immunodepression) at day 1 after stroke onset was independently and highly predictive for post-stroke infections. INTERPRETATION: PANTHERIS suggests that preventive administration of moxifloxacin is superior in reducing infections after severe non-lacunar ischemic stroke compared to placebo. In addition, the results emphasize the pivotal role of immunodepression in developing post-stroke infections. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN74386719

    Pneumonia and in-hospital mortality in the context of neurogenic oropharyngeal dysphagia (NOD) in stroke and a new NOD step-wise concept

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    The aim of our work was to develop a step-wise concept for investigating neurogenic oropharyngeal dysphagia (NOD) that could be used by both trained nursing staff as well as swallowing therapists and physicians to identify patients with NOD at an early stage and so enable an appropriate therapy to be started. To achieve this objective, we assessed uniform terminology and standard operating procedures (SOP) in a new NOD step-wise concept. In-house stroke mortality rates and rates of pneumonia were measured over time (2003–2009) in order to show improvements in quality of care. In addition, outcome measures in a stroke-unit monitoring system were studied after neurorehabilitation (day 90) assessing quality of life (QL) and patient feedback. An investigation that was carried out in the context of internal and external quality assurance stroke projects revealed a significant correlation between the NOD step-wise concept and low rates of pneumonia and in-house mortality. The quality of life measures show a delta value that can contribute to “post-stroke” depression. The NOD step-wise concept (NSC) should, on the one hand, be capable of being routinely used in clinical care and, on the other, being able to fulfil the requirements of being scientifically based for investigating different stages of swallowing disorders. The value of our NSC relates to the effective management of clinical resources and the provision of adequate diagnostic and therapeutic options for different grades of dysphagia. We anticipate that our concept will provide substantial support to physicians, as well as swallowing therapists, in clinical settings and rehabilitation facilities, thereby promoting better guidance and understanding of neurogenic dysphagia as a concept in acute and rehabilitation care, especially stroke-unit settings
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