189 research outputs found

    Climate model bias correction and the role of timescales

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    It is well known that output from climate models cannot be used to force hydrological simulations without some form of preprocessing to remove the existing biases. In principle, statistical bias correction methodologies act on model output so the statistical properties of the corrected data match those of the observations. However the improvements to the statistical properties of the data are limited to the specific time scale of the fluctuations that are considered. For example, a statistical bias correction methodology for mean daily values might be detrimental to monthly statistics. Also, in applying bias corrections derived from present day to scenario simulations, an assumption is made of persistence of the bias over the largest timescales. We examine the effects of mixing fluctuations on different time scales and suggest an improved statistical methodology, referred to here as a cascade bias correction method, that eliminates, or greatly reduces, the negative effects

    Predição do consumo de matéria seca de cabras leiteiras durante a gestação.

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    Resumo: O período da gestação é caracterizado por importantes mudanças fisiológicas no corpo materno tais como a diminuição da ingestão de alimento no último terço de gestação em fêmeas com gestação de múltiplos fetos. O objetivo desse estudo foi desenvolver modelos para predizer a ingestão de matéria seca (IMS) em cabras durante gestação simples e gemelar. Parar este estudo, foram usadas 1820 observações de IMS, obtidos diariamente a partir de sete cabras com gestação gemelar e seis cabras com gestação simples a partir do primeiro dia até os 140 dias de gestação. A IMS diária foi ajustada em três modelos não lineares, os quais foram avaliados através do critério de informação Bayesiana (BIC) como um indicador de melhor ajuste do modelo aos dados. O modelo que melhor se ajustou aos dados foi o modelo quadrático, com valor de BIC de 11549. Os interceptos e coeficientes de regressões do modelo quadrático utilizado para predição do IMS diário foram diferentes entre gestação simples e gemelar (P< 0.01). Comparado as cabras com gestação simples, as cabras com gestação gemelar tiveram maior decréscimo na IMS durante a gestação. Esse decréscimo na IMS em fêmeas com gestação gemelar se deve principalmente a mudanças hormonais e a maior compressão ruminal causada pelo maior tamanho de seus úteros grávidos. Os modelos desenvolvidos nesse estudo devem de ser considerados no manejo nutricional de cabras leiteiras durante a gestação. [Prediction of dry matter intake of dairy goats during pregnancy]. Abstract: The pregnancy is characterized by important physiological changes in maternal body such as a decrease on feed intake in the last third of pregnancy mainly in pregnancy of multiples fetuses. The objective of this study was to develop a model to predict the dry matter intake (DMI) of dairy goats carrying single and twin fetuses throughout pregnancy. For this study it was used a total of 1820 individual records of DMI from seven goats carrying twins and six goats carrying single fetuses. The DMI was daily recorded from the first up to 140 days of pregnancy. The daily DMI as a proportion of the average BW was fitted to tree non-linear models which were evaluated considering the Bayesian information criterion (BIC) value as an indicator how well the model fit the data. The best model fitting the data was the quadratic model with had BIC value of 11549. The intercepts and the slopes of the quadratic models used to predict the daily DMI were different between litter sizes (P < 0.01). Goats carrying twin fetuses showed a greater decrease in the DMI during pregnancy compared to goats carrying single fetus. The decrease of feed intake in females carrying twins may be mainly related to hormonal changes and a greatest rumen compression due to the biggest size of the gravid uterus. The models developed in this study may be relevant in the adoption of nutritional management of dairy goats during the pregnancy

    Delivering Patient Decision Aids on the Internet: Definitions, Theories, Current Evidence, and Emerging Research Areas

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    Background: In 2005, the International Patient Decision Aids Standards Collaboration identified twelve quality dimensions to guide assessment of patient decision aids. One dimension — the delivery of patient decision aids on the Internet — is relevant when the Internet is used to provide some or all components of a patient decision aid. Building on the original background chapter, this paper provides an updated definition for this dimension, outlines a theoretical rationale, describes current evidence, and discusses emerging research areas. Methods: An international, multidisciplinary panel of authors examined the relevant theoretical literature and empirical evidence through 2012. Results: The updated definition distinguishes Internet-delivery of patient decision aids from online health information and clinical practice guidelines. Theories in cognitive psychology, decision psychology, communication, and education support the value of Internet features for providing interactive information and deliberative support. Dissemination and implementation theories support Internet-delivery for providing the right information (rapidly updated), to the right person (tailored), at the right time (the appropriate point in the decision making process). Additional efforts are needed to integrate the theoretical rationale and empirical evidence from health technology perspectives, such as consumer health informatics, user experience design, and human-computer interaction. Despite Internet usage ranging from 74% to 85% in developed countries and 80% of users searching for health information, it is unknown how many individuals specifically seek patient decision aids on the Internet. Among the 86 randomized controlled trials in the 2011 Cochrane Collaboration ’ s review of patient decision aids, only four studies focused on Internet-delivery. Given the limited number of published studies, this paper particularly focused on identifying gaps in the empirical evidence base and identifying emerging areas of research. Conclusions: As of 2012, the updated theoretical rationale and emerging evidence suggest potential benefits to delivering patient decision aids on the Internet. However, additional research is needed to identify best practices and quality metrics for Internet-based development, evaluation, and dissemination, particularly in the areas of interactivity, multimedia components, socially-generated information, and implementation strategies

    Compton Scattering by the Proton using a Large-Acceptance Arrangement

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    Compton scattering by the proton has been measured using the tagged-photon facility at MAMI (Mainz) and the large-acceptance arrangement LARA. The new data are interpreted in terms of dispersion theory based on the SAID-SM99K parameterization of photo-meson amplitudes. It is found that two-pion exchange in the t-channel is needed for a description of the data in the second resonance region. The data are well represented if this channel is modeled by a single pole with mass parameter m(sigma)=600 MeV. The asymptotic part of the spin dependent amplitude is found to be well represented by pi-0-exchange in the t-channel. A backward spin-polarizability of gamma(pi)=(-37.1+-0.6(stat+syst)+-3.0(model))x10^{-4}fm^4 has been determined from data of the first resonance region below 455 MeV. This value is in a good agreement with predictions of dispersion relations and chiral pertubation theory. From a subset of data between 280 and 360 MeV the resonance pion-photoproduction amplitudes were evaluated leading to a E2/M1 multipole ratio of the p-to-Delta radiative transition of EMR(340 MeV)=(-1.7+-0.4(stat+syst)+-0.2(model))%. It was found that this number is dependent on the parameterization of photo-meson amplitudes. With the MAID2K parameterization an E2/M1 multipole ratio of EMR(340 MeV)=(-2.0+-0.4(stat+syst)+-0.2(model))% is obtained

    Photoproduction of scalar mesons on protons and nuclei

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    We study the photoproduction of scalar mesons close to the threshold of f_0(980) and a_0(980) using a unitary chiral model. Peaks for both resonances show up in the invariant mass distributions of pairs of pseudoscalar mesons. A discussion is made on the photoproduction of these resonances in nuclei, which can shed light on their nature, a subject of continuous debate.Comment: 25 pages, 9 figures, accepted for publication in Phys Rev

    Photoproduction of pi0-mesons from nuclei

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    Photoproduction of neutral pions from nuclei (carbon, calcium, niobium, lead) has been studied for incident photon energies from 200 MeV to 800 MeV with the TAPS detector using the Glasgow photon tagging spectrometer at the Mainz MAMI accelerator. Data were obtained for the inclusive photoproduction of neutral pions and the partial channels of quasifree single pi0, double pi0, and pi0pi+/- photoproduction. They have been analyzed in terms of the in-medium behavior of nucleon resonances and the pion - nucleus interaction. They are compared to earlier measurements from the deuteron and to the predictions of a Boltzmann-Uehling-Uhlenbeck (BUU) transport model for photon induced pion production from nuclei.Comment: 15 pages, 22 figures, accepted for publication in EPJ

    Subthreshold rho^0 photoproduction on 3He

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    A large reduction of the rho^0 mass in the nuclear medium is reported, inferred from dipion photoproduction spectra in the 1 GeV region, for the reaction 3He(gamma,pi+ pi-)X with a 10% duty factor tagged-photon beam and the TAGX multi-particle spectrometer. The energy range covered (800 < E(gamma) < 1120 MeV) lies mostly below the free rho^0 production threshold, a region which is believed sensitive to modifications of light vector-meson properties at nuclear-matter densities. The rho^0 masses extracted from the MC fitting of the data, m*(rho^0) = 642 +/- 40, 669 +/- 32, and 682 +/- 56 MeV/c^2 for E(gamma) in the 800-880, 880-960, and 960-1040 MeV regions respectively, are independently corroborated by a measured, assumption-free, kinematical observable. This mass shift, far exceeding current mean-field driven theoretical predictions, may be suggestive of rho^0 decay within the range of the nucleonic field.Comment: 40 pages, 13 figures, submitted to Phys. Rev.

    The MentDis_ICF65+ study protocol: prevalence, 1-year incidence and symptom severity of mental disorders in the elderly and their relationship to impairment, functioning (ICF) and service utilisation.

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    Background: The EU currently lacks reliable data on the prevalence and incidence of mental disorders in older people. Despite the availability of several national and international epidemiological studies, the size and burden of mental disorders in the elderly remain unclear due to various reasons. Therefore, the aims of the MentDis_ICF65+ study are (1) to adapt existing assessment instruments, and (2) to collect data on the prevalence, the incidence, and the natural course and prognosis of mental disorders in the elderly. Method/design: Using a cross-sectional and prospective longitudinal design, this multi-centre study from six European countries and associated states (Germany, Great Britain, Israel, Italy, Spain, and Switzerland) is based on age-stratified, random samples of elderly people living in the community. The study program consists of three phases: (1) a methodological phase devoted primarily to the adaptation of age- and gender-specific assessment tools for older people (e.g., the Composite International Diagnostic Interview, CIDI) as well as psychometric evaluations including translation, back translation; (2) a baseline community study in all participating countries to assess the lifetime, 12 month and 1 month prevalence and comorbidity of mental disorders, including prior course, quality of life, health care utilization and helpseeking, impairments and participation and, (3) a 12 month follow-up of all baseline participants to monitor course and outcome as well as examine predictors. Discussion: The study is an essential step forward towards the further development and improvement of harmonised instruments for the assessment of mental disorders as well as the evaluation of activity impairment and participation in older adults. This study will also facilitate the comparison of cross-cultural results. These results will have bearing on mental health care in the EU and will offer a starting point for necessary structural changes to be initiated for mental health care policy at the level of mental health care politics

    Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis

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    Masses, widths and photocouplings of baryon resonances are determined in a coupled-channel partial wave analysis of a large variety of data. The Bonn-Gatchina partial wave formalism is extended to include a decomposition of t- and u-exchange amplitudes into individual partial waves. The multipole transition amplitudes for γppπ0\gamma p\to p\pi^0 and γpnπ+\gamma p\to n\pi^+ are given and compared to results from other analyses.Comment: 18 pages, 14 figure

    Study approach and field work procedures of the MentDis_ICF65+ project on the prevalence of mental disorders in the older adult European population

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    Background This study describes the study approach and field procedures of the MentDis_ICF65+ study, which aims to assess the prevalence of mental disorders in older adults. Methods An age-appropriate version of the Composite International Diagnostic Interview (CIDI65+) was developed and tested with regard to its feasibility and psychometric properties in a pre-test and pilot phase. In the cross-sectional survey an age-stratified, random sample of older adults (65–84 years) living in selected catchment areas of five European countries and Israel was recruited. Results N = 3142 participants (mean age 73.7 years, 50.7% female) took part in face-to-face interviews. The mean response rate was 20% and varied significantly between centres, age and gender groups. Sociodemographic differences between the study centres appeared for the place of birth, number of grandchildren, close significants, retirement and self-rated financial situation. The comparison of the MentDis_ICF65+ sample with the catchment area and country population of the study centres revealed significant differences, although most of these were numerically small. Conclusions The study will generate new information on the prevalence of common mental disorders among older adults across Europe using an age-appropriate, standardized diagnostic instrument and a harmonized approach to sampling. Generalizability of the findings and a potentially limited representativeness are discussed
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