A SEMI-MARKOV MODEL FOR EAR INFECTION

A recent study of the prevalence of middle ear infection among Australian aborigines reports, for different age groups, the number currently infected, the number currently not infected and the number who are currently not infected but have scarring of the ear drum showing evidence of a previous infection. Incidence and recovery are modelled by a semi-Markov model in which incidence of the infection is allowed to be nonstationary.     

Risk/Benefit Assessments of Human Diseases: Optimum Dose for Intervention

A simple procedure is proposed in order to quantify the tradeoff between a loss suffered from an illness due to exposure to a microbial pathogen and a loss due to a toxic effect, perhaps a different illness, induced by a disinfectant employed to reduce the microbial exposure. Estimates of these two types of risk as a function of disinfectant dose and their associated relative losses provide information for the estimation of the optimum dose of disinfectant that minimizes the total expected loss. The estimates of the optimum dose and expected relative total loss were similar regardless of whether the beta-Poisson, log-logistic, or extreme value function was used to model the risk of illness due to exposure to a microbial pathogen. This is because the optimum dose of the disinfectant and resultant expected minimum loss depend upon the estimated slope (first derivative) of the models at low levels of risk, which appear to be similar for these three models at low levels of risk. Similarly, the choice among these three models does not appear critical for estimating the slope at low levels of risk for the toxic effect induced by the use of a disinfectant. For the proposed procedure to estimate the optimum disinfectant dose, it is not necessary to have absolute values for the losses due to microbial-induced or disinfectant-induced illness, but only relative losses are required. All aspects of the problem are amenable to sensitivity analyses. The issue of risk/benefit tradeoffs, more appropriately called risk/risk tradeoffs, does not appear to be an insurmountable problem.     

汕优63在四川省水稻区试中的产量和抗病性分析

对汕优63自1986年至1993年在四川省水稻区域试验中的产量表现和抗稻瘟病鉴定结果分析表明，汕优63由高产、稳产、中抗指瘟病而逐渐丧失抗性，产量呈波动状态，1993年降至最低点。指出了现阶段水稻栽培必须以多组合当家。     

疾病与时尚的观念交织——医疗社会史视角下的民国成都娼妓及其日常生活

民国成都的娼妓数量众多,性病的社会传染问题特别突出?在各种性病治疗方式中,西医的九一四标准化治疗以其有效性与方便性,成为社会认同的最优治疗方案?娼妓?性病与九一四等性病药品建构了普遍认知中的娼妓生活?与此同时,脂粉?美容药品与时髦穿着等符号表征,又建构着娼妓生活的另一个面相?娼妓的“疾病”与“时尚”,对于宏大的历史来说,只是一个小小的碎片,但是对于历史的整体重构却有重要意义?     

Importance of active listening in treating workers with musculoskeletal disorders

Abstract

Female assembly workers reporting constant neck and shoulder pain, despite ergonomically acceptable working conditions, were interviewed. As a starting point in the interviews, the patients were asked to describe their general situation at work. Their reports were fed back and discussed with company management in a wider group meeting and resulted in an improvement in their attitudes to those workers. A climate of confidence and well-being was created, which the women experienced as genuine. The workers' report of pains improved dramatically and absence due to musculoskeletal disorders was reduced by more than 90% during the following year.     

Flexible estimation of serial correlation in nonlinear mixed models

In the conventional linear mixed-effects model, four structures can be distinguished: fixed effects, random effects, measurement error and serial correlation. The latter captures the phenomenon that the correlation structure within a subject depends on the time lag between two measurements. While the general linear mixed model is rather flexible, the need has arisen to further increase flexibility. In addition to work done in the area, we propose the use of spline-based modeling of the serial correlation function, so as to allow for additional flexibility. This approach is applied to data from a pre-clinical experiment in dementia which studied the eating and drinking behavior in mice.     

Hand-Hygiene Mitigation Strategies Against Global Disease Spreading through the Air Transportation Network

The risk for a global transmission of flu-type viruses is strengthened by the physical contact between humans and accelerated through individual mobility patterns. The Air Transportation System plays a critical role in such transmissions because it is responsible for fast and long-range human travel, while its building components—the airports—are crowded, confined areas with usually poor hygiene. Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) consider hand hygiene as the most efficient and cost-effective way to limit disease propagation. Results from clinical studies reveal the effect of hand washing on individual transmissibility of infectious diseases. However, its potential as a mitigation strategy against the global risk for a pandemic has not been fully explored. Here, we use epidemiological modeling and data-driven simulations to elucidate the role of individual engagement with hand hygiene inside airports in conjunction with human travel on the global spread of epidemics. We find that, by increasing travelers engagement with hand hygiene at all airports, a potential pandemic can be inhibited by 24% to 69%. In addition, we identify 10 airports at the core of a cost-optimal deployment of the hand-washing mitigation strategy. Increasing hand-washing rate at only those 10 influential locations, the risk of a pandemic could potentially drop by up to 37%. Our results provide evidence for the effectiveness of hand hygiene in airports on the global spread of infections that could shape the way public-health policy is implemented with respect to the overall objective of mitigating potential population health crises.     

《白衣女人》中疾病的隐喻

《白衣女人》中的人物很多是患有疾病的，如劳拉的家族遗传病神经症，玛丽安所得的伤寒，珀西瓦尔的父亲天生是畸形等。疾病是作者塑造人物形象的手段，也成为某种现象的隐喻。在《白衣女人》中神经症是英国不健全的法律制度的隐喻，也是英国上层社会某些家族血液中流传的精神上和道德上的缺陷的隐喻。     

Estimation of the basic reproduction number for infectious diseases from age-stratified serological survey data

The basic reproduction number of an infection, R ₀, is the average number of secondary infections generated by a single typical infective individual in a totally susceptible population. It is directly related to the effort required to eliminate infection. We consider statistical methods for estimating R ₀ from age-stratified serological survey data. The main difficulty is indeterminacy, since the contacts between individuals of different ages are not observed. We show that, given an estimate of the average age-specific hazard of infection, a particular leading left eigenfunction is required to specify R ₀. We review existing methods of estimation in the light of this indeterminacy. We suggest using data from several infections transmitted via the same route, and we propose that the choice of model be guided by a criterion based on similarity of their contact functions. This approach also allows model uncertainty to be taken into account. If one infection induces no lasting immunity, we show that the only additional assumption required to estimate R ₀ is that the contact function is symmetric. When matched data on two or more infections transmitted by the same route are available, the methods may be extended to incorporate the effect of individual heterogeneity. The approach can also be applied in partially vaccinated populations and to populations comprising loosely linked communities. The methods are illustrated with data on hepatitis A, mumps, rubella, parvovirus, Haemophilus influenzae type b and measles infection.     

A Quantitative Microbial Risk Assessment Model for Legionnaires'' Disease: Animal Model Selection and Dose-Response Modeling

Legionnaires' disease (LD), first reported in 1976, is an atypical pneumonia caused by bacteria of the genus Legionella, and most frequently by L. pneumophila (Lp). Subsequent research on exposure to the organism employed various animal models, and with quantitative microbial risk assessment (QMRA) techniques, the animal model data may provide insights on human dose-response for LD. This article focuses on the rationale for selection of the guinea pig model, comparison of the dose-response model results, comparison of projected low-dose responses for guinea pigs, and risk estimates for humans. Based on both in vivo and in vitro comparisons, the guinea pig (Cavia porcellus) dose-response data were selected for modeling human risk. We completed dose-response modeling for the beta-Poisson (approximate and exact), exponential, probit, logistic, and Weibull models for Lp inhalation, mortality, and infection (end point elevated body temperature) in guinea pigs. For mechanistic reasons, including low-dose exposure probability, further work on human risk estimates for LD employed the exponential and beta-Poisson models. With an exposure of 10 colony-forming units (CFU) (retained dose), the QMRA model predicted a mild infection risk of 0.4 (as evaluated by seroprevalence) and a clinical severity LD case (e.g., hospitalization and supportive care) risk of 0.0009. The calculated rates based on estimated human exposures for outbreaks used for the QMRA model validation are within an order of magnitude of the reported LD rates. These validation results suggest the LD QMRA animal model selection, dose-response modeling, and extension to human risk projections were appropriate.