Exercising caution: social physique anxiety and protective self-presentational behaviour

This study examined relations among body mass index (BMI), social physique anxiety (SPA) and protective self-presentational exercise behaviours in a sample of 86 female participants in aerobics classes at a university fitness centre. Participants completed a questionnaire assessing demographic and exercise-related information, the 9-item version of the Social Physique Anxiety Scale, and measures of two forms of protective self-presentational exercise behaviour (i.e., preferring to stand away from the aerobics instructor and wearing concealing exercise attire). Consistent with previous research, SPA was positively associated with both preferred exercise studio floor position (r = .31, p < .05) and clothing concealingness (r = .25, p < .05). SPA did not mediate the relations between BMI and either of the two protective self-presentational behaviours. BMI was a better predictor of clothing concealingness than SPA, but the opposite was found for exercise studio floor position preferences (r = .31 with SPA versus r = .15 with BMI). The findings provide an enhanced understanding of factors associated with self-presentation in exercise.     

磷酸根离子对羟基磷灰石溶解度的影响

目的：应用固体滴定方法监测羟基磷灰石(Hydroxyaptite，HA)的溶解平衡过程，观察磷酸根离子对HA溶解度的影响。方法：HA为固体滴定物。半导体二极管激光为发射光源，散射光源探测器用于监测溶液中HA的溶解平衡过程并判断超越溶解平衡点所出现的沉淀。氯化钾(KC1，0．1M)和磷酸钾(KH2PO4，1mM)混合液为测试溶液体系。固体滴定总量用于代表溶解度等温线的数据点。结果：在KC1／KH2PO4混合液中所得HA溶解度等温线(37(C)高于其在KC1溶液中所得。结论：溶液体系中磷酸根离子增加HA的溶解度。推测该现象与磷酸根离子形成的配合物密切相关。     

Causal assessment of occupational standing or walking and low back pain: results of a systematic review

Background contextLow back pain (LBP) is a widespread musculoskeletal condition that frequently occurs in the working-age population. Numerous occupational physical activities have been implicated in its etiology.PurposeTo conduct a systematic review establishing a causal relationship between occupational standing or walking and LBP.Study designSystematic review of the literature.SampleStudies reporting an association between occupational standing or walking and LBP.Outcome measuresNumerical association between exposure to standing or walking and the presence of LBP.MethodsA systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria for causality, between occupational standing or walking and LBP. A search was conducted using MEDLINE, Embase, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and expert knowledge. Evaluation of methodological quality was performed using a modified Newcastle-Ottawa Scale.ResultsThis search yielded 2,766 citations. Eighteen studies met the inclusion criteria. Five were high-quality studies related to standing, and two were high-quality studies related to walking. For occupational standing and LBP, there was moderate to strong evidence against the association criterion, the only study examining dose response did not support this criterion, four studies examining temporality failed to support this criterion, and only one study discussed the biological plausibility criterion. For occupational walking and LBP, there was moderate evidence against a causal relationship with respect to the association, temporality, dose response, and biological plausibility criteria. No studies assessed the experiment criterion for these activities.ConclusionsA summary of existing studies was not able to find any high-quality studies that satisfied more than two of the Bradford-Hill causation criteria for occupational standing or walking and LBP. Based on the evidence reviewed, it is unlikely that occupational standing or walking is independently causative of LBP in the populations of workers studied.     

A Globally Optimal k-Anonymity Method for the De-Identification of Health Data

Background

Explicit patient consent requirements in privacy laws can have a negative impact on health research, leading to selection bias and reduced recruitment. Often legislative requirements to obtain consent are waived if the information collected or disclosed is de-identified.

Objective

The authors developed and empirically evaluated a new globally optimal de-identification algorithm that satisfies the k-anonymity criterion and that is suitable for health datasets.

Design

Authors compared OLA (Optimal Lattice Anonymization) empirically to three existing k-anonymity algorithms, Datafly, Samarati, and Incognito, on six public, hospital, and registry datasets for different values of k and suppression limits.

Measurement

Three information loss metrics were used for the comparison: precision, discernability metric, and non-uniform entropy. Each algorithm's performance speed was also evaluated.

Results

The Datafly and Samarati algorithms had higher information loss than OLA and Incognito; OLA was consistently faster than Incognito in finding the globally optimal de-identification solution.

Conclusions

For the de-identification of health datasets, OLA is an improvement on existing k-anonymity algorithms in terms of information loss and performance.