6,669 research outputs found
Review on the epidemiology and dynamics of BSE epidemics
The paper describes how the comprehensive surveillance of bovine spongiform encephalopathy (BSE) and studies carried out on these data has enhanced our knowledge of the epidemiology of BSE. Around 7 000 BSE cases were detected through the screening of about 50 million cattle with rapid tests in Europe. It confirmed that the clinical surveillance had a poor capacity to detect cases, and also showed the discrepancy of this passive surveillance efficiency between regions and production types (dairy/beef). Other risk factors for BSE were being in a dairy herd (three times more than beef), having a young age at first calving (for dairy cattle), being autumn-born (dairy and beef), and being in a herd with a very high milk yield. These findings focus the risk on the feeding regimen of calves/heifers. Several epidemiological studies across countries suggest that the feedborne source related to meat and bone meal (MBM) is the only substantiated route of infection ¿ even after the feed ban ¿, while it is not possible to exclude maternal transmission or milk replacers as a source of some infections. In most European countries, the average age of the cases is increasing over time and the prevalence decreasing, which reflects the effectiveness of control measures. Consistent results on the trend of the epidemic were obtained using back-calculation modelling, the R0 approach and Age-Period-Cohort models. Furthermore, active surveillance also resulted in the finding of atypical cases. These are distinct from previously found BSE and classified in two different forms based on biochemical characteristics; their prevalence is very low (36 cases up to 1st September 2007), affected animals were old and some of them displayed clinical signs. The origin and possibility of natural transmission is unknown
HCV Innate Immune Responses
Hepatitis C virus (HCV) establishes a persistent infection in more than 70% of infected individuals. This striking ability to evade the powerful innate immune system results from viral interference occurring at several levels of the interferon (IFN) system. There is strong evidence from cell culture experiments that HCV can inhibit the induction of IFNβ by cleaving important proteins in the virus sensory pathways of cells such as MAVS and TRIF. There is also evidence that HCV interferes with IFNα signaling through the Jak-STAT pathway, and that HCV proteins target IFN effector systems such as protein kinase R (PKR). These in vitro findings will have to be confirmed in clinical trials investigating the molecular mechanisms of HCV interference with the innate immune system in liver samples
Effects of alcohol and illegal drugs on at-risk adolescents' behavior: a review of the scientific publications between 1997 and 2007
CONTEXTO: Pesquisas internacionais apontam para fatores de risco relacionados à prática infracional, entre eles, a forte associação entre abuso de substâncias e delinqüência juvenil. Contudo, poucos estudos brasileiros foram publicados com intuito de se verificar essa relação. OBJETIVOS: Realizar uma revisão sobre pesquisas que têm como foco o tema álcool, drogas e delinqüência, verificando a relação entre o uso de substâncias psicoativas e a delinqüência juvenil. MÉTODOS: A revisão abrangeu artigos cientÃficos publicados entre 1997 e 2007, sendo efetuada a pesquisa com base nos seguintes descritores: adolescence, alcohol, drugs, delinquency. CONCLUSÕES: Estudos apontam que o uso de álcool e drogas ilÃcitas entre indivÃduos que estão em situação de risco é alto e precoce em relação a adolescentes que não estão em situação de risco, demonstrando que é uma parte do problema da delinqüência.BACKGROUND: International research indicates that there is a strong association between substance abuse and juvenile delinquency and the risk factors related to law infraction. In Brazil however, few studies have been carried out to investigate such relationships. OBJECTIVES: The aim of this study was to conduct a review of the research that focuses on the topics of alcohol, drugs, and delinquency; verifying the relationship between psychoactive drug abuse and juvenile delinquency. METHODS: A review of scientific papers published from 1997 to 2007 selected on the basis of the keywords: adolescence, alcohol, illegal drugs, and delinquency. CONCLUSIONS: Studies indicate that the use of alcohol and illegal drugs among at-risk adolescents is high, and starts early when compared with non-risk adolescents; suggesting that the substance abuse is an important part of the at-risk delinquency problems
Improved simulation of phase change processes in applications where conduction is the dominant heat transfer mode
This is the post-print of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierThis paper reports on the development, experimental validation and application of a semi-empirical model for the simulation of the phase change process in phase change materials (PCM). PCMs are now increasingly being used in various building materials such as plasterboard, concrete or panels to improve thermal control in buildings and accurate modelling of their behaviour is important to effectively capture the effects of storage on indoor thermal conditions. Unlike many commercial simulation packages that assume very similar melting and freezing behaviour for the PCM and no hysteresis, the methodology employed treats the melting and freezing processes separately and this allows the inclusion of the effect of hysteresis in the modelling. As demonstrated by the results in this paper, this approach provides a more accurate prediction of the temperature and heat flow in the material, which is of particular importance in providing accurate representation of indoor thermal conditions during thermal cycling. The difference in the prediction accuracy of the two methods is a function of the properties of the PCM. The smaller the hysteresis of the PCM, the lower will be the prediction error of the conventional approach, and solution time will become the determining factor in selecting the simulation approach in practical applications.This work is funded from the Engineering and Physical Sciences Research Council (EPSRC) of the UK, Grant No: EP/H004181/1
La vallée de l'Escaut à Pont-à -Chin
The sudden opening of a karst pipe in the abandoned bed of the Scheldt River has exposed 8 m ofHolocene deposits; their stratigraphy, archaeological contents, fossil fauna and flora are studied here. A well dated early occupation is from the First Iron Age to Early La Tène (around 650-450 B.C.), a second one from Roman times (around 50-200 A.D.); they permit a close control of the14 C dates, which are systematically too old, due to reworking in the stream. Vertebrate and molluscan assemblages are discussed separatel
Outgassing of icy bodies in the Solar System - II. Heat transport in dry, porous surface dust layers
In this work, we present a new model for the heat conductivity of porous dust
layers in vacuum, based on an existing solution of the heat transfer equation
of single spheres in contact. This model is capable of distinguishing between
two different types of dust layers: dust layers composed of single particles
(simple model) and dust layers consisting of individual aggregates (complex
model). Additionally, we describe laboratory experiments, which were used to
measure the heat conductivity of porous dust layers, in order to test the
model. We found that the model predictions are in an excellent agreement with
the experimental results, if we include radiative heat transport in the model.
This implies that radiation plays an important role for the heat transport in
porous materials. Furthermore, the influence of this new model on the Hertz
factor are demonstrated and the implications of this new model on the modeling
of cometary activity are discussed. Finally, the limitations of this new model
are critically reviewed.Comment: Submitted to Icaru
La faune en Région predésertique dans le Nord de l’Afrique. Facteurs de dégradation, moyens de sauvegarde
The relative influence of neighbourhood incivilities, cognitive social capital, club membership and individual characteristics on positive mental health
Previous research indicates that residents׳ perceptions of their neighbourhoods can have an adverse influence on their health and wellbeing over and above the influence of structural disadvantage. Contrary to most prior research, this study employed an indicator of positive wellbeing and assessed the impact of individual characteristics, perceived social and environmental incivilities, indicators of cognitive and structural social capital, and perceived safety. Analyses of data from a large regional UK representative study (n=8237; 69.64% response rate) found the most influential determinants of wellbeing were physical health problems, age, SES and cognitive social capital. Smaller, significant effects were also found for environmental and social incivilities, and for perceived safety. The effect of cognitive social capital was moderated by age, with a stronger effect found among those aged 65 years and over than among younger participants. Findings indicate that the promotion of positive mental health within communities may be facilitated by efforts to foster a greater sense of belonging among residents, and that older adults may benefit most from such efforts
Prediction of 90-day mortality in older patients after discharge from an emergency department: a retrospective follow-up study
Background: Older people frequently attend the emergency department (ED) and have a high risk of poor outcome as compared to their younger counterparts. Our aim was to study routinely collected clinical parameters as predictors of 90-day mortality in older patients attending our ED. Methods: We conducted a retrospective follow-up study at the Leiden University Medical Center (The Netherlands) among patients aged 70 years or older attending the ED in 2012. Predictors were age, gender, time and way of arrival, presenting complaint, consulting medical specialty, vital signs, pain score and laboratory testing. Cox regression analyses were performed to analyse the association between these predictors and 90-day mortality. Results: Three thousand two hundred one unique patients were eligible for inclusion. Ninety-day mortality was 10.5 % for the total group. Independent predictors of mortality were age (hazard ratio [HR] 1.06, 95 % confidence interval [95 % CI] 1.04-1.08), referral from another hospital (HR 2.74, 95 % CI 1.22-6.11), allocation to a non-surgical specialty (HR: 1.55, 95 % CI 1.13-2.14), increased respiration rate (HR up to 2.21, 95 % CI 1.25-3.92), low oxygen saturation (HR up to 1.96, 95 % CI 1.19-3.23), hypothermia (HR 2.27, 95 % CI 1.28-4.01), fever (HR 0.43, 95 % CI 0.24-0.75), high pain score (HR 1.55, 95 % CI 1.03-2.32) and the indication to perform laboratory testing (HR 3.44, 95 % CI 2.13-5.56). Conclusions: Routinely collected parameters at the ED can predict 90-day mortality in older patients presenting to the ED. This study forms the first step towards creating a new and simple screening tool to predict and improve health outcome in acutely presenting older patients
Efeitos do uso do álcool e das drogas ilÃcitas no comportamento de adolescentes de risco: uma revisão das publicações cientÃficas entre 1997 e 2007
BACKGROUND: International research indicates that there is a strong association between substance abuse and juvenile delinquency and the risk factors related to law infraction. In Brazil however, few studies have been carried out to investigate such relationships. OBJECTIVES: The aim of this study was to conduct a review of the research that focuses on the topics of alcohol, drugs, and delinquency; verifying the relationship between psychoactive drug abuse and juvenile delinquency. METHODS: A review of scientific papers published from 1997 to 2007 selected on the basis of the keywords: adolescence, alcohol, illegal drugs, and delinquency. CONCLUSIONS: Studies indicate that the use of alcohol and illegal drugs among at-risk adolescents is high, and starts early when compared with non-risk adolescents; suggesting that the substance abuse is an important part of the at-risk delinquency problems.CONTEXTO: Pesquisas internacionais apontam para fatores de risco relacionados à prática infracional, entre eles, a forte associação entre abuso de substâncias e delinqüência juvenil. Contudo, poucos estudos brasileiros foram publicados com intuito de se verificar essa relação. OBJETIVOS: Realizar uma revisão sobre pesquisas que têm como foco o tema álcool, drogas e delinqüência, verificando a relação entre o uso de substâncias psicoativas e a delinqüência juvenil. MÉTODOS: A revisão abrangeu artigos cientÃficos publicados entre 1997 e 2007, sendo efetuada a pesquisa com base nos seguintes descritores: adolescence, alcohol, drugs, delinquency. CONCLUSÕES: Estudos apontam que o uso de álcool e drogas ilÃcitas entre indivÃduos que estão em situação de risco é alto e precoce em relação a adolescentes que não estão em situação de risco, demonstrando que é uma parte do problema da delinqüência
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