1,658 research outputs found

    Optimal projection of observations in a Bayesian setting

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    Optimal dimensionality reduction methods are proposed for the Bayesian inference of a Gaussian linear model with additive noise in presence of overabundant data. Three different optimal projections of the observations are proposed based on information theory: the projection that minimizes the Kullback-Leibler divergence between the posterior distributions of the original and the projected models, the one that minimizes the expected Kullback-Leibler divergence between the same distributions, and the one that maximizes the mutual information between the parameter of interest and the projected observations. The first two optimization problems are formulated as the determination of an optimal subspace and therefore the solution is computed using Riemannian optimization algorithms on the Grassmann manifold. Regarding the maximization of the mutual information, it is shown that there exists an optimal subspace that minimizes the entropy of the posterior distribution of the reduced model; a basis of the subspace can be computed as the solution to a generalized eigenvalue problem; an a priori error estimate on the mutual information is available for this particular solution; and that the dimensionality of the subspace to exactly conserve the mutual information between the input and the output of the models is less than the number of parameters to be inferred. Numerical applications to linear and nonlinear models are used to assess the efficiency of the proposed approaches, and to highlight their advantages compared to standard approaches based on the principal component analysis of the observations

    Hematologic and biochemical reference intervals in Shetland Sheepdogs

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    Background: Several breeds have physiological peculiarities that induce variations in reference intervals (RIs) compared with the general canine population. Shetland sheepdogs (SSs) are reported to be more predisposed to different diseases (eg, hyperlipidemia, gallbladder mucocele, and hypothyroidism). Consequently, a breed-specific approach is more often required. Objectives: The aim of this study was to determine whether the RIs of the general canine population could be applied to that of SSs, and to generate breed-specific RIs, where appropriate. Methods: Sixty\ua0clinically healthy and fasted SSs (36% of the population registered at the Italian Breed association) were examined. Routine hematology and biochemistry analyses were performed. The transference method was used to compare the results of SSs with the RIs of the general canine population. When these RIs were not validated, new RIs were generated according to the guidelines of the American Society of Veterinary Clinical Pathology. Differences associated with sex, age, coat color, and whether used as a pet, a herding dog, or an agility dog were also investigated. Results: The transference method validated for 30/38 SS RIs. For 6 of the remaining 8 variables, the difference with the claimed RIs could depend on preanalytical or analytical artifacts, whereas for glucose and total cholesterol, these differences could depend on breed peculiarities. However, in all SSs, the concentration of cholesterol was <12.95\ua0mmol/L. Relevant differences associated with sex, age, coat color, and use were not found. Conclusions: This study suggests that breed-specific RIs should be used for glucose and cholesterol in SSs

    Frequency of electrophoretic changes in urine of old cats with or without CKD

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    A reservoir for inverse power law decoherence of a qubit

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    The exact dynamics of a Jaynes-Cummings model for a qubit interacting with a continuous distribution of bosons, characterized by a special form of the spectral density, is evaluated analytically. The special reservoir is designed to induce anomalous decoherence, resulting in an inverse power law relaxation, of power 3/2, over an evaluated long time scale. If compared to the exponential-like relaxation obtained from the original Jaynes-Cummings model for Lorentzian-type spectral density functions, decoherence is strongly suppressed. The special reservoir exhibits an upper band edge frequency coinciding with the qubit transition frequency. Known theoretical models of photonic band gap media suitable for the realization of the designed reservoir are proposed.Comment: 5 pages, 2 figure

    Big endothelin-1 in cats with CKD : preliminary evaluation

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    In human medicine the concentration of serum endothelin-1 (ET-1)increases in hypertension and CKD. Also urinary ET-1 correlates withthe severity of renal disease and the magnitude of proteinuria. In dogs,increased concentration of ET-1, evaluated indirectly by the precursorBig Endothelin-1 (big-ET1), seems to be associated with the severityof CKD and hypertension.The aim of this study was to gain information about serum and urinarylevels of big-ET1 in cats with CKD, with and without hypertensionand proteinuria

    Has VZV epidemiology changed in Italy? Results of a seroprevalence study

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    The aim of the study was to evaluate if and how varicella prevalence has changed in Italy. In particular a seroprevalence study was performed, comparing it to similar surveys conducted in pre-immunization era. During 2013–2014, sera obtained from blood samples taken for diagnostic purposes or routine investigations were collected in collaboration with at least one laboratory/center for each region, following the approval of the Ethics Committee. Data were stratified by sex and age. All samples were processed in a national reference laboratory by an immunoassay with high sensitivity and specificity. Statutory notifications, national hospital discharge database and mortality data related to VZV infection were analyzed as well. A total of 3707 sera were collected and tested. In the studied period both incidence and hospitalization rates decreased and about 5 deaths per year have been registered. The seroprevalence decreased in the first year of life in subjects passively protected by their mother, followed by an increase in the following age classes. The overall antibody prevalence was 84%. The comparison with surveys conducted with the same methodology in 1996–1997 and 2003–2004 showed significant differences in age groups 1–19&nbsp;y. The study confirms that in Italy VZV infection typically occurs in children. The impact of varicella on Italian population is changing. The comparison between studies performed in different periods shows a significant increase of seropositivity in age class 1–4&nbsp;years, expression of vaccine interventions already adopted in some regions

    Banco de dados de pragas quarentenárias A1: apoio ao sistema de análise de risco de introdução e estabelecimento de pragas quarentenárias do Estado de São Paulo.

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    A análise de risco de introdução e estabelecimento de pragas quarentenárias demanda tanto o levantamento de pragas com potencial quarentenário quanto à organização e a agilidade na recuperação de informações detalhadas sobre essas pragas. O Laboratório de Quarentena ?Costa Lima? da Embrapa Meio Ambiente, no âmbito de projeto aprovado no Edital MAPA/CNPq Nº 64/2008, vem desenvolvendo um sistema informatizado (SysRiskQuarantine) para subsidiar essa análise de risco para os cultivos de eucalipto, citros, cana-de-açúcar e flores/plantas ornamentais no Estado de São Paulo. O sistema, desenvolvido em servidor Apache 2.0 e linguagens MySQL/HTML/PHP, viabilizará bancos de dados com informações sobre os principais municípios produtores do estado e sobre as pragas (presentes e quarentenárias), acessadas via formulários eletrônicos elaborados para a recuperação dinâmica on-line dos dados neles inseridos. O presente trabalho apresenta o banco de dado de pragas quarentenárias A1 do SysRiskQuarantine. O trabalho recuperou informações sobre 376 das 430 pragas A1 da Instrução Normativa nº 41 de 01 de julho de 2008 do MAPA (não incluídas 66 plantas infestantes/parasitas) quanto ao ataque aos cultivos. Fez uso de informações de literatura técnico-científica, de contatos com pesquisadores da área e de sites na internet para classificá-las, sempre que possível. Como resultado, 155 pragas A1, dentre as que foram recuperadas, apresentaram potencial para atacar eucalipto, citros, cana-de-açúcar e/ou flores e plantas ornamentais, prioritárias para estudos no projeto

    Validation of a questionnaire for young women to assess knowledge, attitudes and behaviors towards cervical screening and vaccination against HPV in Italy

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    Background: Despite knowledge about HPV may be an important determinant for vaccine acceptance and uptake, only few studies have assessed HPV-related knowledge in young females. The aim of this study was to assess the reliability and validity of the questionnaire, in Italian women ≥18 years old, as a tool to examine knowledge, attitudes and behaviors towards screening and vaccination against HPV and reliable source of information. Methods: The questionnaire was administered to 30 girls in anonymous, voluntary and self -administered form with close-ended type of questions, except for the socio-demographic characteristics. It was composed in 3 sections for a total of 69 items. Participation in the study was entirely voluntary and anonymous. Descriptive analyses were performed using frequencies, percentages, and frequency table for categorical variables. Reliability analysis was tested and content validity was evaluated using Cronbach's alpha to check internal consistency and avoid misinterpretation of the results. The study was conducted in 4 Italian cities: Ferrara, Rome, Cassino and Palermo, to represent the different Italian geographical areas and knowledge, attitudes and behaviors towards screening and vaccination against HPV and reliable source of information. Data were collected in October 2010. Statistical analysis was performed with the statistical software for Windows SPSS, version 19.0. Results: The highest value of Cronbach's alpha resulted on 24 items (alpha= 0,774); the addition of other items, one at a time, decreased the value. Cronbach's alpha on all the 3 sections together resulted in a value of 0, 059. Young women generally knew that HPV can cause cervical cancer (93.3%) and genital warts (16.7%) and 76.7% of them recognized Pap-test as a screening tool. The main sources of information about HPV vaccination are represented by magazines / books (33.3%), TV (26.7%), and gynecologists (23.3%). Conclusions: This pilot study demonstrated that a short version of the questionnaire has very good reliability properties in the study and this needs to be taken into account for future studies
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