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Gender equality and workforce diversity has recently been in the forefront of College discussions. Reasons for the difference between various groups may not be as they initially appeared. The results of comparing the outcome between two groups can sometimes be confounded and even reversed by an unrecognised third variable. This concept is known as Simpson's Paradox, and is illustrated here using a renowned case study on potential gender bias for acceptance to Graduate School at the University of California, Berkeley.  The investigation showed that males were 1.8 times more likely to be admitted to Graduate School than females in 1973. Initially it appeared that women were discriminated against in the selection process. However, when admissions were re-examined at individual Departments of the School, admission tended to be better for women than men in four of six Departments. This contradiction or paradox tells us that the association between admission and gender was dependent upon on Department.  The confounding effect of Department was defined by two characteristics. Firstly, a strong association between Department and admission: some Departments admitted much smaller percentages of applicants than others. Secondly, a strong association between Department and gender: females tended to apply to Departments with lower admission rates.  The explanation of differences between groups can be multifactorial. A search for possible confounders will assist in this understanding. This could apply whenever two groups initially appear to differ, but on closer analysis this difference is either unfounded, or even reversed by reference to a third, confounding variable., (© 2018 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.)

We developed a first- and second-order sensitivity analysis approach with the decoupled direct method to examine spatial and temporal variations of ozone-limiting reagents and the importance of local vs upwind emission sources in the San Joaquin Valley of central California for a 5 day ozone episode (Jul 29th to Aug 3rd, 2000). Despite considerable spatial variations, nitrogen oxides (NO(x)) emission reductions are overall more effective than volatile organic compound (VOC) control for attaining the 8 h ozone standard in this region for this episode, in contrast to the VOC control that works better for attaining the prior 1 h ozone standard. Interbasin source contributions of NO(x) emissions are limited to the northern part of the SJV, while anthropogenic VOC (AVOC) emissions, especially those emitted at night, influence ozone formation in the SJV further downwind. Among model input parameters studied here, uncertainties in emissions of NO(x) and AVOC, and the rate coefficient of the OH + NO2 termination reaction, have the greatest effect on first-order ozone responses to changes in NO(x) emissions. Uncertainties in biogenic VOC emissions only have a modest effect because they are generally not collocated with anthropogenic sources in this region.

Simultaneous temporally resolved indoor and outdoor measurements of ammonia and nitric acid are valuable for determining the gas-particle equilibrium conditions governing concentrations of ammonium nitrate aerosol. We report the results of simultaneous automated indoor and outdoor measurements of ammonia and nitric acid concentrations made at an unoccupied, single-story residence in Clovis, CA during three periods from October 2000 to January 2001. The measurements were conducted as part of a controlled study to explore mechanisms governing indoor concentrations of fine aerosols of outdoor origin. The gas-phase measurements were performed using diffusion denuders and ion chromatography with 30 min temporal resolution and detection limits below 1 ppb. The conditions of the field experiment span a wide range of outdoor climate as well as natural and forced indoor conditions. During all periods ammonia concentrations were generally slightly higher indoors than out, with both outdoor and indoor concentrations varying in a range from approximately 5 to 30 ppb. Nitric acid was only detected in outdoor air in October 2000, at concentrations up to 3 ppb. During the October period, the product of outdoor nitric acid and ammonia concentrations sometimes deviated from that expected for equilibrium between gas and ammonium nitrate particulate phases and the degree and direction of disequilibrium were correlated with trends in air temperature. The consistently low indoor concentrations of nitric acid were not consistent with equilibrium between gas and particle phases and suggest that a combination of low penetration into the building and a high loss rate for nitric acid reduce indoor concentrations significantly below those outdoors.