Expertise and Ideology in Statistical Evaluation of Circumcision for Protection against HIV Infection

Aim: To critically evaluate data and arguments by Van Howe defending his stance opposing male circumcision (MC), in particular his meta-regression analyses evaluating the ability of MC to reduce HIV infection risk in heterosexual populations within and outside Africa. Methods: We performed metaregression analysis of log odds of HIV infection between uncircumcised and circumcised men using a single covariate (MC prevalence) in the meta-regression model involving the metareg package in STATA 13 for 103 populations worldwide and for populations within Africa. The meta-regression of log odds and MC prevalence was fitted to a line, as were empirical Bayes estimates resulting from post-estimation. Results: Our critical evaluation of Van Howe’s arguments attempting to undermine the scientific evidence in support of the benefits of MC in protection of men against HIV during heterosexual intercourse, as well as other infections and conditions, together with his use of statistics to support his beliefs, revealed serious flaws, obfuscation and missing data. We therefore performed our own meta-regression analysis using a trivariate model. Doing so revealed that for MC prevalences of 50%, 75% and 100% for general populations within Africa, odds ratios for HIV risk in uncircumcised vs. circumcised men were 1.35, 1.58 and 1.85, respectively. Our meta-regression analysis of data for all countries yielded similar findings. For a general population outside Africa with 100% MC prevalence, OR was 1.5. Van Howe failed to acknowledge that since MC prevalence in US whites (91%) and blacks (76%) exceeds 75% his results support MC having a protective effect in those population groups. Conclusions: The protective effect of MC against HIV infection during heterosexual intercourse applies to populations both within and outside Africa. The debate engineered by MC opponents, and led by Van Howe, now appears to have run its course. The scientific evidence has prevailed.

Test the effectiveness of building safety guidance signs in a T-junction corridor based on eye movement data

Evacuation signs are a key factor in the effectiveness of occupants'urgent escape from buildings.Different sign features may have disparate impacts on individual and crowd behavior.This study aims to quantitatively inves-tigate the effectiveness of building evacuation signs with different features during pedestrian evacuation using eye-tracking devices.Ten experiments were conducted in a building in T-junction scenarios,and four sets of features related to evacuation signs(color,position,graphics,and flashing)were considered.SMI BeGaze was used to analyze the eye movements of the occupants.The fixation duration of the evacuees and the ratio of signs detected and followed were quantitatively derived and compared for each experiment.The results show that it is easier for evacuees to detect signs at a low sightline,and signs posted at that level of sight can provide better guidance.When signs are posted high up,red signs are easier to detect than green signs.Most evacuees prefer to follow the evacuation signs once they detect them;however,there is no significant difference in the effect of what is posted on the evacuation signs,such as a running man or an arrow.Conversely,flashing of signs is highly helpful in influencing evacuees'behavior,but flashing is not helpful in detecting signs.More importantly,red signs with a running man graphic located in a low position have the best guiding effects on evacuees.The fixa-tion behaviors of evacuees vary according to sign features,particularly in regard to flashing and color.Evacuees stare longer at twinkling signs.Differences in the colors and positions of signs result in significantly different perceptual behaviors among evacuees.Our findings are useful for building designers and provide guidance for developing effective evacuation strategies.