应用回归法预测石家庄市细菌性痢疾发病

目的 预测石家庄市细菌性痢疾(菌痢)的流行趋势,为进一步制订防治对策提供参考依据.方法 运用Excel软件对该地区2001-2009年的菌痢发病率进行二次多项式拟合,并根据所建立的预测方程对2010年的菌痢发病进行外推预测,分析其变化趋势.结果 建立的石家庄市2001-2009年的菌痢发病预测模型为:y=0.4748x...     

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??The position of lips directly affects facial beauty. In orthodontic treatment process??clinicians always choose incisor retraction to adjust lip protrusion?? reshaping the soft tissue beauty. However??with the retraction of incisors??the change of lip soft tissue is not in a simple same-size ratio. To ideally rebuild lip shape??the exact prediction of retraction extent of incisor is a widely-concerned problem. This study investigated the response of lip position to incisor position??aiming to provide a reference for further clinical treatment.     

Analytical and simulation methods for estimating the potential predictive ability of genetic profiling: a comparison of methods and results

Various modeling methods have been proposed to estimate the potential predictive ability of polygenic risk variants that predispose to various common diseases. However, it is unknown whether differences between them affect their conclusions on predictive ability. We reviewed input parameters, assumptions and output of the five most common methods and compared their estimates of the area under the receiver operating characteristic (ROC) curve (AUC) using hypothetical data representing effect sizes and frequencies of genetic variants, population disease risk and number of variants. To assess the accuracy of the estimated AUCs, we aimed to reproduce the AUCs of published empirical studies. All methods assumed that the combined effect of genetic variants on disease risk followed a multiplicative risk model of independent genetic effects, but they either assumed per allele, per genotype or dominant/recessive effects for the genetic variants. Modeling strategy and input parameters differed. Methods used simulation analysis or analytical formulas with effect sizes quantified by odds ratios (ORs) or relative risks. Estimated AUC values were similar for lower ORs (<1.2). When AUCs were larger (>0.7) due to variants with strong effects, differences in estimated AUCs between methods increased. The simulation methods accurately reproduced the AUC values of empirical studies, but the analytical methods did not. We conclude that despite differences in input parameters, the modeling methods estimate similar AUC for realistic values of the ORs. When one or more variants have stronger effects and AUC values are higher, the simulation methods tend to be more accurate.     

When emulation becomes reciprocity

It is well known that perceiving another''s body movements activates corresponding motor representations in an observer''s brain. It is nevertheless true that in many situations simply imitating another''s actions would not be an effective or appropriate response, as successful interaction often requires complementary rather than emulative movements. At what point does the automatic tendency to mirror another''s actions become the inclination to carry out appropriate, complementary movements? In the present study, single-pulse transcranial magnetic stimulation (TMS) was used to explore corticospinal excitability in participants observing action sequences evoking imitative or complementary movements. TMS was delivered at five time points corresponding to different moments in time when key kinematic landmarks characterizing an observed action occurred. A variation in motor evoked potentials (MEPs) confirmed that the motor system flexibly shifts from imitative to complementary action tendencies. That shift appears to take place very precociously in time. Observers are attuned to advance movement information and can use it to anticipate a future course of action and to prepare for an appropriate, complementary action. Altogether, these findings represent a step forward in research concerning social action-perception coupling mechanisms providing important data to better understand the role of predictive simulation in social contexts.     

An Experimental Model of Heat Storage in Working Firefighters

Objective. Develop experimental models to study uncompensable heat stress (UCHS) in working firefighters (FFs). Methods. FFs ingested core temperature (Tc) capsules prior to performing sequential tasks in 40°C andpersonal protective ensemble (PPE), or 18°C andno PPE. Both trials were conducted in an environmental chamber with FFs using self-contained breathing apparatus (SCBA). Results. FFs exercising in heat andPPE reproduced UCHS conditions. For every FF in both trials for whom the capsules worked, Tc was elevated, andTc_max occurred after completion of study protocol. Trials with PPE resulted in a mean maximum temperature of 38.94°C (± 0.37°C); Tc_max reached 40.4°C. Without PPE, maximum Tc averaged 37.79°C (± 0.07°C). Heat storage values ranged from 131 to 1205 kJ, averaging 578 kJ (± 151.47kJ) with PPE and210.83 kJ (± 21.77kJ) without PPE. Conclusions. An experimental model has been developed that simulates the initial phases of an interior fire attack to study the physiology of UCHS in FF. The hot environment andPPE increase maximum Tc andheat storage over that due to the exertion required to perform the tasks andmay decrease time to volitional fatigue. This model will permit controlled studies to optimize work-rest cycles, rehab conditions, andphysical conditioning of FFs.     

应用ARIMA模型预测福建省戊型肝炎疫情

目的建立福建省戊型肝炎（戊肝）分月发病数预测预警的ARIMA时间序列模型。方法利用SAS 9.0软件的PROC ARIMA综合软件包对《疾病监测信息报告管理系统》收集的福建省2004-2010年戊肝分月发病数序列进行ARI-MA模型的建模与分析。结果福建省2004-2010年戊肝分月发病数序列含有以年为周期的季节效应,经12步差分后为平稳非白噪声序列,拟合的相对最优模型为ARIMA（0,0,0）×（0,1,1）12。结论拟合戊肝的相对最优ARIMA模型进行预测和预警,具有实际应用价值。     

Effects of FRAX Model Calibration on Intervention Rates: A Simulation Study

The WHO fracture risk assessment tool (FRAX^®) estimates an individual’s 10-yr major osteoporotic and hip fracture probabilities using a tool customized to the fracture epidemiology of a specific population. Incorrect model calibration could therefore affect performance of the model in clinical practice. The current analysis was undertaken to explore how simulated miscalibration in the FRAX^® tool would affect the numbers of individuals meeting specific intervention criteria (10-yr major osteoporotic fracture probability ≥20%, 10-yr hip fracture probability ≥3%). The study cohort included 36,730 women and 2873 men aged 50 yr and older with FRAX^® probability estimates using femoral neck bone mineral density. We simulated relative miscalibration error in 10% increments from −50% to +50% relative to a correctly calibrated FRAX^® model. We found that small changes in model calibration (even on the order of 10%) had large effects on the number of individuals qualifying for treatment. There was a steep gradient in the relationship between relative change in calibration and relative change in intervention rates: for every 1% change in calibration, there was a 2.5% change in intervention rates for women and 4.1% for men. For hip fracture probability, the gradient of the relationship was closer to unity. These results highlight the importance of FRAX^® model calibration, and speak to the importance of using high-quality fracture epidemiology in constructing FRAX^® tools.     

Predicted hexameric structure of the Agrobacterium VirB4 C terminus suggests VirB4 acts as a docking site during type IV secretion

The Agrobacterium T-DNA transporter belongs to a growing class of evolutionarily conserved transporters, called type IV secretion systems (T4SSs). VirB4, 789 aa, is the largest T4SS component, providing a rich source of possible structural domains. Here, we use a variety of bioinformatics methods to predict that the C-terminal domain of VirB4 (including the Walker A and B nucleotide-binding motifs) is related by divergent evolution to the cytoplasmic domain of TrwB, the coupling protein required for conjugative transfer of plasmid R388 from Escherichia coli. This prediction is supported by detailed sequence and structure analyses showing conservation of functionally and structurally important residues between VirB4 and TrwB. The availability of a solved crystal structure for TrwB enables the construction of a comparative model for VirB4 and the prediction that, like TrwB, VirB4 forms a hexamer. These results lead to a model in which VirB4 acts as a docking site at the entrance of the T4SS channel and acts in concert with VirD4 and VirB11 to transport substrates (T-strand linked to VirD2 or proteins such as VirE2, VirE3, or VirF) through the T4SS.