The Furrowed Face: the depiction of the elderly in painting, England and the United States, 1870-1910

Old age has always evoked diametrically opposed opinions. On the one hand, the elderly are respected, regarded as benevolent repositories of wisdom and comfort; on the other, they are considered as decrepit vestiges of life, who pointlessly linger on, wasting the world for the vibrant and useful. These views were particularly topical in the last decades of the nineteenth/first decade of the twentieth centuries, when there was increasing concern in many countries about the aged and their vulnerability. In England and Wales this resulted in the 1908 provision by the government of an old age pension. In the United States, however, provision of support from the state was introduced significantly later, in the 1930s. How, if at all, was this variation in view reflected in the painting of the elderly in the two countries? This study addresses this question by firstly considering how the elderly are portrayed in genre painting in each country. It then moves on to the world of portraits, looking in more detail at the work of individual artists, both American and English, including Thomas Eakins, John Singer Sargent and Hubert Herkomer. In England it emerged that the elderly were often shown as happy if shabby, with a more submissive attitude to fate; there was also a significant segment of painting which recorded the poverty and difficulties which may face the old. In contrast, in the United States the elderly were shown as vibrant, assertive and materially better off, with few indications of the troubles they may undergo. In both countries, however, it became clear that the elderly were regarded in a positive way by artists, who delighted in the excellent practice of artistic skills provided by the time-ravaged faces and features of the old

Variance Estimation and Construction of Confidence Intervals for GEE Estimator

The sandwich estimator, also known as the robust covariance matrix estimator, has achieved increasing use in the statistical literature as well as with the growing popularity of generalized estimating equations (GEE). A modified sandwich variance estimator is proposed, and its consistency and efficiency are studied. It is compared with other variance estimators, such as a model based estimator, the sandwich estimator and a corrected sandwich estimator. Confidence intervals for regression parameters based on these estimators are discussed. Simulation studies using clustered data to compare the performance of variance estimators are reported

Statistical modelling to predict silicosis risk in deceased Southern African gold miners without medical evaluation

The Qhubeka Trust was established in 2016 in a legal settlement on behalf of former gold miners seeking compensation for silicosis contracted on the South African mines. Settlements resulting from lawsuits on behalf of gold miners aim to provide fair compensation. However, occupational exposure and medical records kept by South African mining companies for their employees have been very limited. Some claimants to the Qhubeka Trust died before medical evaluation was possible, thus potentially disadvantaging their dependants from receiving any compensation. With medical evaluation no longer possible, a statistical approach to this problem was developed. The records for claimants with medical evaluation were used to develop a logistic regression prediction model for the likelihood of silicosis, based on the potential predictors: cumulative exposure to respirable dust, age, years since first exposure, years of life lost prematurely, vital status at 31 December 2019, and a history of tuberculosis diagnosis. The prediction model allowed estimation of the likelihood of silicosis for each miner who had died without medical evaluation and is a novel approach in this setting. In addition, we were able to quantitatively evaluate the trade-offs of different silicosis risk classification thresholds in terms of true and false positives and negatives. Significance:• A statistical approach can be used for risk estimation in settings where the outcome of interest is unknown for some members of a class.• The likelihood of silicosis in deceased miners without medical evaluation in the Qhubeka Trust can be accurately estimated, using information from finalised claims.• Strategies for classifying the silicosis status of deceased miners without medical evaluation in theQhubeka Trust can be assessed in a rigorous, quantitative framework

Small-scale health-related indicator acquisition using secondary data spatial interpolation

<p>Abstract</p> <p>Background</p> <p>Due to the lack of small-scale neighbourhood-level health related indicators, the analysis of social and spatial determinants of health often encounter difficulties in assessing the interrelations of neighbourhood and health. Although secondary data sources are now becoming increasingly available, they usually cannot be directly utilized for analysis in other than the designed study due to sampling issues. This paper aims to develop data handling and spatial interpolation procedures to obtain small area level variables using the Canadian Community Health Surveys (CCHS) data so that meaningful small-scale neighbourhood level health-related indicators can be obtained for community health research and health geographical analysis.</p> <p>Results</p> <p>Through the analysis of spatial autocorrelation, cross validation comparison, and modeled effect comparison with census data, kriging is identified as the most appropriate spatial interpolation method for obtaining predicted values of CCHS variables at unknown locations. Based on the spatial structures of CCHS data, kriging parameters are suggested and potential small-area-level health-related indicators are derived. An empirical study is conducted to demonstrate the effective use of derived neighbourhood variables in spatial statistical modeling. Suggestions are also given on the accuracy, reliability and usage of the obtained small area level indicators, as well as further improvements of the interpolation procedures.</p> <p>Conclusions</p> <p>CCHS variables are moderately spatially autocorrelated, making kriging a valid method for predicting values at unsampled locations. The derived variables are reliable but somewhat smoother, with smaller variations than the real values. As potential neighbourhood exposures in spatial statistical modeling, these variables are more suitable to be used for exploring potential associations than for testing the significance of these associations, especially for associations that are barely significant. Given the spatial dependency of current health-related risks, the developed procedures are expected to be useful for other similar health surveys to obtain small area level indicators.</p

Profiling heteroscedasticity in linear regression models

Diagnostics for heteroscedasticity in linear regression models have been intensively investigated in the literature. However, limited attention has been paid on how to identify covariates associated with heteroscedastic error variances. This problem is critical in correctly modelling the variance structure in weighted least squares estimation, which leads to improved estimation efficiency. We propose covariate‐specific statistics based on information ratios formed as comparisons between the model‐based and sandwich variance estimators. A two‐step diagnostic procedure is established, first to detect heteroscedasticity in error variances, and then to identify covariates the error variance structure might depend on. This proposed method is generalized to accommodate practical complications, such as when covariates associated with the heteroscedastic variances might not be associated with the mean structure of the response variable, or when strong correlation is present amongst covariates. The performance of the proposed method is assessed via a simulation study and is illustrated through a data analysis in which we show the importance of correct identification of covariates associated with the variance structure in estimation and inference. The Canadian Journal of Statistics 43: 358–377; 2015 © 2015 Statistical Society of CanadaRésuméLes outils de diagnostic pour l'hétéroscédasticité dans les modèles de régression linéaire sont largement étudiés dans la littérature. Toutefois, l'identification des covariables associées aux variances hétéroscédastiques n'a suscité que peu d'intérêt. Ce problème joue pourtant un rôle clé pour l'estimation par les moindres carrés pondérés, puisque la modélisation correcte de la structure de variance accroî t l'efficacité de l'estimation. Les auteurs proposent des statistiques spécifiques aux covariables fondées sur un ratio d'information comparant l'estimateur de la variance basé sur le modèle à l'estimateur sandwich de la variance. Ils développent une procédure diagnostique en deux étapes, détectant d'abord l'hétéroscédasticité et identifiant ensuite les covariables dont peut dépendre la structure de variance. Ils généralisent la méthode proposée afin d'accommoder des complications pratiques telles que l'absence de lien entre la structure de la moyenne et une covariable associée avec l'hétéroscédasticité, ou la forte corrélation des covariables. Les auteurs évaluent la performance de la méthode proposée à l'aide d'une étude de simulation et l'illustrent en analysant un jeu de données montrant l'importance d'identifier correctement les covariables associées avec la structure de variance pour l'estimation et l'inférence. La revue canadienne de statistique xx: 1–20; 2015 © 2015 Société statistique du CanadaPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113149/1/cjs11252.pd

Fluid Restriction Dehydration Increase Core Temperature During Endurance Exercise Compared to Exercise Induced Dehydration

International Journal of Exercise Science 15(2): 166-176, 2022. This study aimed to evaluate the difference in heart rate and core temperature during aerobic exercise between two forms of dehydration: exercise-induced (EI) and fluid restricted (FR). Twenty-two subjects (N = 22; 83.35 ± 13.92 kg) completed the current study, performing a familiarization session, a pre-experimental exercise session, and two exercise testing sessions. The EI exercise trial (81.52 ± 13.72 kg) was conducted after performing exercise in a hot environment to lose three to four percent of body weight and partial rehydration. The FR exercise trial (81.53 ± 14.14 kg) was completed after 12 hours of fluid restriction. During both exercise sessions, subjects pedaled against a set resistance of 130 watts for 30 minutes. The main effect of hydration on Tc was significant, F(1, 18) = 4.474, p = .049, ηp2 = .199 (Figure 2) with core temperature being greater during the FR trial compared to the EI trial (FR = 37.58 ± .06°C vs. EI = 37.31 ± .11°C). No significant interaction was found between hydration and time for HR, F(2, 42) = 0.120, p = .887, ηp2 = .006. The main effect of time on HR was significant, F(2, 42) = 119.664, p \u3c .001, ηp2 = .851. Fluid restriction was associated with an increase in core temperature. An increased core temperature may negatively influence performance, and care should be taken to ensure proper hydration

The Relationship between Physical Inactivity and Family Life Course Stage

Physical inactivity is a well-documented risk factor for numerous chronic diseases and a major public health problem in Canada. Since social-ecological models suggest that behaviour is influenced by the person as well as the social and physical environment, it is important to be sensitive to other factors when examining physical activity participation. The purpose of this study was to explore the associations between physical inactivity, marital status and family stage for men and women in Canada. The study was based on data from the Canadian Community Health Survey, Cycle 2.1, for adults aged 18-64 living with a spouse or partner (with or without children) or single living with children. Respondents were classified as inactive or active according to self-reported leisure-time physical activity. Logistic regression was used to examine gender differences in the relationship between household composition and physical inactivity. Explanatory variables included parents’ age, sex, age of youngest child, income adequacy and interview mode. Family stage was significantly associated with adult physical inactivity levels. Individuals with very young children (\u3c 6 years old) were more likely to be inactive compared to childless adults or those with older children (\u3e12 years old). Having children between 6-12 years old was related to increased physical activity, possibly due to more family leisure pursuits involving physical activity. Living with a partner was associated with greater physical inactivity, particularly when controlling for income adequacy. Furthermore, those with high income adequacy were less likely to be inactive, and having a very young child increased this difference. In conclusion, family life course stage and income adequacy were most influential in determining levels of physical inactivity. Therefore, physically active leisure programs targeting adults with very young children, particularly those at lower income levels, may be helpful in increasing physical activity and decreasing health risks associated with inactivity. Margo Hilbrecht is a Postdoctoral Fellow at the University of Guelph’s Centre for Families, Work and Well-Being. She recently received her Ph.D. from the University of Waterloo in Recreation and Leisure Studies. Her research focuses on time use and work-life integration as it pertains to non-traditional work arrangements, gender and leisure. These interests extend to perceptions of time pressure and stress associated with the coordination of employment, school, and leisure activities in families with school-age children. Her current research explores the social and health consequences of unpredictable work schedules for parents employed in the retail sector

Protein Engineering of a Spectroscopic Probe into Malate Dehydrogenase (MDH)

Malate dehydrogenase (MDH) is an enzyme that has a key role in biological processes, like the Krebs cycle. Specifically, it reversibly catalyzes the interconversion of (S)-malate with NAD+ to oxaloacetate and NADH. Once oxaloacetate is synthesized, MDH dispatches it to citrate synthase, but it is not clear how this happens. One theory is that MDH channels it to citrate synthase by forming a metabolon, a mechanism for direct channeling, preventing diffusion of reaction intermediates into a bulk matrix. There is a lack of research in this area due to the absence of a spectroscopic probe necessary to visualize MDH’s conformational changes. Therefore, a method was tested to incorporate a fluorescent landmark into MDH’s structure and thus be used in future research to reveal the interactions between MDH and citrate synthase. Specific amino acids of MDH were mutated to tryptophan, an amino acid known to fluoresce (V189, I319, A120, I136, P119, G218). The coding sequence for the wildtype MDH and mutant MDHs were incorporated into plasmids and bacterially transformed into Escherichia coli. Both wildtype and mutant proteins were over-expressed, then purified by nickel affinity chromatography using a hexahistidine tag on the N-terminus of MDH. Data will demonstrate that I139W, V189W, and A120W had significantly lower activity than wildtype MDH, and the same is predicted for I136W. I139W and V189W emitted fluorescence at 290 nm, but I136W did not. The mutations P119W and G218W could not be overexpressed or purified. Next steps in design of a fluorescent, active MDH will be discussed