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41.
A Stochastic Model to Assess the Effect of Meat Inspection Practices on the Contamination of the Pig Carcasses 下载免费PDF全文
Eduardo de Freitas Costa Luis Gustavo Corbellini Ana Paula Serafini Poeta da Silva Maarten Nauta 《Risk analysis》2017,37(10):1849-1864
The objective of meat inspection is to promote animal and public health by preventing, detecting, and controlling hazards originating from animals. With the improvements of sanitary level in pig herds, the hazards profile has shifted and the inspection procedures no longer target major foodborne pathogens (i.e., not risk based). Additionally, carcass manipulations performed when searching for macroscopic lesions can lead to cross‐contamination. We therefore developed a stochastic model to quantitatively describe cross‐contamination when consecutive carcasses are submitted to classic inspection procedures. The microbial hazard used to illustrate the model was Salmonella, the data set was obtained from Brazilian slaughterhouses, and some simplifying assumptions were made. The model predicted that due to cross‐contamination during inspection, the prevalence of contaminated carcass surfaces increased from 1.2% to 95.7%, whereas the mean contamination on contaminated surfaces decreased from 1 logCFU/cm² to ?0.87 logCFU/cm², and the standard deviations decreased from 0.65 to 0.19. These results are explained by the fact that, due to carcass manipulations with hands, knives, and hooks, including the cutting of contaminated lymph nodes, Salmonella is transferred to previously uncontaminated carcasses, but in small quantities. These small quantities can easily go undetected during sampling. Sensitivity analyses gave insight into the model performance and showed that the touching and cutting of lymph nodes during inspection can be an important source of carcass contamination. The model can serve as a tool to support discussions on the modernization of pig carcass inspection. 相似文献
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Marloes de Lange Maarten H. J. Wolbers Maurice Gesthuizen Wout C. Ultee 《Revue europeenne de demographie》2014,30(2):161-185
In this paper, we study the impact of macro- and micro-economic uncertainty on family formation between 1970 and 2000 in The Netherlands. Using data of the Family Survey Dutch Population, we analysed the monthly hazard rates of experiencing the transition into first union, first marriage and parenthood after the start of the relationship of 365 male and 364 female partners by applying piecewise-constant exponential models. The results show that macro-economic uncertainties, i.e. high unemployment rates, lead to postponement of the first union and marriage, but not of the first child. In addition, we found that this relationship is not interpreted by individual-level employment insecurity, i.e. temporary employment or unemployment, which does not seem to prevent people from making long-term family commitments. Although hypothesized, we did not find that the negative effects of macro- and micro-level insecurities on family formation reinforce each other or that they vary between individuals with different educational qualifications. 相似文献
44.
The recently developed rolling year GEKS procedure makes maximum use of all matches in the data to construct nonrevisable price indexes that are approximately free from chain drift. A potential weakness is that unmatched items are ignored. In this article we use imputation Törnqvist price indexes as inputs into the rolling year GEKS procedure. These indexes account for quality changes by imputing the “missing prices” associated with new and disappearing items. Three imputation methods are discussed. The first method makes explicit imputations using a hedonic regression model which is estimated for each time period. The other two methods make implicit imputations; they are based on time dummy hedonic and time-product dummy regression models and are estimated on bilateral pooled data. We present empirical evidence for New Zealand from scanner data on eight consumer electronics products and find that accounting for quality change can make a substantial difference. 相似文献
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Ernesto Friedrich de Lima Amaral 《Population research and policy review》2012,31(6):883-905
In Brazil, the age and education compositions of the male labor force is changing with great regional variation. Based on Demographic Census microdata, results indicate that cohort size has a negative impact on earnings, but this effect is decreasing over time. In this study we consider the impact on earnings by age and education, as well as estimated income inequality reduction and racial differentials. Fertility decline and improve regarding educational attainment had a significant influence on the decline of income inequality in the country. Moreover, the non-white population has been experiencing less success in relation to educational achievement, compared to the white population. 相似文献
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Patrícia Monteiro Pascoal Isabel de Santa Bárbara Narciso Nuno Monteiro Pereira 《Journal of sex research》2014,51(1):22-30
Sexual satisfaction is an important indicator of sexual health and is strongly associated with relationship satisfaction. However, research exploring lay definitions of sexual satisfaction has been scarce. We present thematic analysis of written responses of 449 women and 311 men to the question “How would you define sexual satisfaction?” The participants were heterosexual individuals with a mean age of 36.05 years (SD = 8.34) involved in a committed exclusive relationship. In this exploratory study, two main themes were identified: personal sexual well-being and dyadic processes. The first theme focuses on the positive aspects of individual sexual experience, such as pleasure, positive feelings, arousal, sexual openness, and orgasm. The second theme emphasizes relational dimensions, such as mutuality, romance, expression of feelings, creativity, acting out desires, and frequency of sexual activity. Our results highlight that mutual pleasure is a crucial component of sexual satisfaction and that sexual satisfaction derives from positive sexual experiences and not from the absence of conflict or dysfunction. The findings support definitions and models of sexual satisfaction that focus on positive sexual outcomes and the use of measures that incorporate items linked to personal and dyadic sexual rewards for both men and women. 相似文献
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Margaretha de Looze Norman A. Constantine Petra Jerman Evelien Vermeulen-Smit Tom ter Bogt 《Journal of sex research》2015,52(3):257-268
Sexual communication is a principal means of transmitting sexual values, beliefs, expectations, and knowledge from parents to children. Although this area has received considerable research attention, more studies with representative samples are needed to assure that findings are reflective of populations of interest. A nationally representative sample of parent–adolescent dyads (N = 2,965; mean adolescent age = 13.8 years) in the Netherlands was employed to examine the frequency of parent–adolescent sexual communication and its association with adolescent sexual behaviors (defined as sexual initiation, condom use, and contraceptive pill use). Nine communication topics in the areas of anatomy, relationships and rights, and protection and contraception were examined. In all, 75%of parents reported having discussed at least one topic multiple times with their adolescents. Romantic relationships were discussed most frequently. Hierarchical logistic regression analyses indicated that parent–adolescent sexual communication on protection and contraception was positively associated with adolescent sexual initiation and contraceptive pill use but not condom use. This may reflect that adolescents, when they become sexually active, are more likely to discuss sexuality with their parents. Findings are interpreted within the context of Dutch culture, which is generally accepting of adolescent sexuality and characterized by open sexual communication. 相似文献
48.
Prior information is often incorporated informally when planning a clinical trial. Here, we present an approach on how to incorporate prior information, such as data from historical clinical trials, into the nuisance parameter–based sample size re‐estimation in a design with an internal pilot study. We focus on trials with continuous endpoints in which the outcome variance is the nuisance parameter. For planning and analyzing the trial, frequentist methods are considered. Moreover, the external information on the variance is summarized by the Bayesian meta‐analytic‐predictive approach. To incorporate external information into the sample size re‐estimation, we propose to update the meta‐analytic‐predictive prior based on the results of the internal pilot study and to re‐estimate the sample size using an estimator from the posterior. By means of a simulation study, we compare the operating characteristics such as power and sample size distribution of the proposed procedure with the traditional sample size re‐estimation approach that uses the pooled variance estimator. The simulation study shows that, if no prior‐data conflict is present, incorporating external information into the sample size re‐estimation improves the operating characteristics compared to the traditional approach. In the case of a prior‐data conflict, that is, when the variance of the ongoing clinical trial is unequal to the prior location, the performance of the traditional sample size re‐estimation procedure is in general superior, even when the prior information is robustified. When considering to include prior information in sample size re‐estimation, the potential gains should be balanced against the risks. 相似文献
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Astrid M. G. Poorthuis Sander Thomaes Marcel A. G. van Aken Jaap J. A. Denissen Bram Orobio de Castro 《Social Development》2014,23(4):770-783
The transition from primary to secondary school challenges children's psychological well‐being. A cross‐transitional longitudinal study (N = 306; mean age = 12.2 years) examined why some children's self‐esteem decreases across the transition whereas other children's self‐esteem does not. Children's expected social acceptance in secondary school was measured before the transition; their actually perceived social acceptance was measured after the transition. Self‐esteem and Big Five personality traits were measured both pre‐ and posttransition. Self‐esteem changed as a function of the discrepancy between children's expected and actually perceived social acceptance. Furthermore, neuroticism magnified self‐esteem decreases when children's ‘hopes were dashed'—when they experienced disappointing levels of social acceptance. These findings provide longitudinal support for sociometer theory across the critical transition to secondary school. 相似文献