Comparison of telomere length in black and white teachers from South Africa: the sympathetic activity and ambulatory blood pressure in Africans study

OBJECTIVE Telomere length is a marker of biological aging that has been linked to cardiovascular disease risk. The black South African population is witnessing a tremendous increase in the prevalence of cardiovascular disease, part of which might be explained through urbanization. We compared telomere length between black South Africans and white South Africans and examined which biological and psychosocial variables played a role in ethnic difference in telomere length. METHODS We measured leukocyte telomere length in 161 black South African teachers and 180 white South African teachers aged 23 to 66 years without a history of atherothrombotic vascular disease. Age, sex, years having lived in the area, human immunodeficiency virus (HIV) infection, hypertension, body mass index, dyslipidemia, hemoglobin A1c, C-reactive protein, smoking, physical activity, alcohol abuse, depressive symptoms, psychological distress, and work stress were considered as covariates. RESULTS Black participants had shorter (median, interquartile range) relative telomere length (0.79, 0.70-0.95) than did white participants (1.06, 0.87-1.21; p < .001), and this difference changed very little after adjusting for covariates. In fully adjusted models, age (p < .001), male sex (p = .011), and HIV positive status (p = .023) were associated with shorter telomere length. Ethnicity did not significantly interact with any covariates in determining telomere length, including psychosocial characteristics. CONCLUSIONS Black South Africans showed markedly shorter telomeres than did white South African counterparts. Age, male sex, and HIV status were associated with shorter telomere length. No interactions between ethnicity and biomedical or psychosocial factors were found. Ethnic difference in telomere length might primarily be explained by genetic factors.

Progression of cardiovascular risk factors in black Africans: 3 year follow up of the SABPA cohort study

Recent work identified a high prevalence of modifiable risk factors for cardiovascular disease (CVD) among urban black South Africans. The aim was to track the progression of CVD risk factors in a multi-ethnic sample of South Africans. Participants were 173 black (aged 47.5 ± 7.8 yrs) and 186 white teachers (aged 49.6 ± 9.9 yrs) that were examined at baseline and 3 years follow-up. Blacks demonstrated a substantially higher prevalence of composite CVD burden (defined as history of physician diagnosed heart disease, use of anti-hypertensives, anti-diabetic, or statin medications at either time point) compared to whites (49.1 vs. 32.0%, p = 0.012) respectively. After controlling for baseline, the black participants demonstrated greater increases in 24 h systolic and diastolic blood pressure, total cholesterol, fasting glucose, fibrinogen, D-dimer, and waist circumference in comparison with whites. In summary, an adverse progression of CVD risk factors was observed in the whole sample, although to a larger degree in black participants. Aggressive treatment strategies for controlling risk factors in black Africans are needed to reduce the increasing burden of CVD in South Africa.

A Noachian source region for the "Black Beauty" meteorite, and a source lithology for Mars surface hydrated dust?

The Martian surface is covered by a fine-layer of oxidized dust responsible for its red color in the visible spectral range (Bibring et al., 2006; Morris et al., 2006). In the near infrared, the strongest spectral feature is located between 2.6 and 3.6 mu m and is ubiquitously observed on the planet (Jouglet et al., 2007; Milliken et al., 2007). Although this absorption has been studied for many decades, its exact attribution and its geological and climatic implications remain debated. We present new lines of evidence from laboratory experiments, orbital and landed missions data, and characterization of the unique Martian meteorite NWA 7533, all converging toward the prominent role of hydroxylated ferric minerals. Martian breccias (so-called "Black Beauty" meteorite NWA7034 and its paired stones NWA7533 and NWA 7455) are unique pieces of the Martian surface that display abundant evidence of aqueous alteration that occurred on their parent planet (Agee et al., 2013). These dark stones are also unique in the fact that they arose from a near surface level in the Noachian southern hemisphere (Humayun et al., 2013). We used IR spectroscopy, Fe-XANES and petrography to identify the mineral hosts of hydrogen in NWA 7533 and compare them with observations of the Martian surface and results of laboratory experiments. The spectrum of NWA 7533 does not show mafic mineral absorptions, making its definite identification difficult through NIR remote sensing mapping. However, its spectra are virtually consistent with a large fraction of the Martian highlands. Abundant NWA 7034/7533 (and paired samples) lithologies might abound on Mars and might play a role in the dust production mechanism. (C) 2015 Elsevier B.V. All rights reserved.

The Improving Relative Status of Black Men

Using data from the Current Population Survey, we examine recent trends in the relative economic status of black men. Our findings point to gains in the relative wages of black men (compared to whites) during the 1990s, especially among younger workers. In 1989, the average black male worker (experienced or not) earned about 69 percent as much per week as the average white male worker. In 2001, the average younger black worker was earning about 86% percent as much as an equally experienced white male; black males at all experience levels earned 72 percent as much as the average white in 2001. Greater occupational diversity and a reduction in unobserved skill differences and/or labor market discrimination explain much of the trend. For both younger and older workers, general wage inequality tempered the rate of wage convergence between blacks and whites during the 1990s, although the effects were less pronounced than during the 1980s.

The Black-White Achievement Gap Amongst Struggling Readers: A Case Study of Early Intervention Outcomes in Massachusetts

A number of analyses of large data sets have suggested that the reading achievement gap between African American and White U.S. is negligible or small at school entry, but widens substantially during the school years because African American students show slower rates of growth in elementary and secondary school. Identifying when and why gaps occur, therefore, is a an important research endeavor. In addition, being able to predict which African American children are most likely to fall behind can contribute to efforts to close the achievement gap. This paper analyzes first grade and third grade data on African American and White children in Massachusetts who all were identified in first grade as struggling readers and enrolled in Reading Recovery—an individualized intervention. All the children were low-income and attending urban schools. Using Observation Survey data from first grade, and MCAS Reading data from 3rd grade, we found that the African American and White students made equal average progress while in first grade, but by the end of third grade showed a large gap in MCAS proficiency rates. We discuss the results in terms of school quality, reading development, dialect issues, testing formats, and the need to provide long-term support to vulnerable learners.

Now You See it, Now You Don't: Why Do Real Estate Agents Withhold Available Houses from Black Customers?

Potential home buyers may initiate contact with a real estate agent by asking to see a particular advertised house. This paper asks whether an agent's response to such a request depends on the race of the potential buyer or on whether the house is located in an integrated neighborhood. We build on previous research about the causes of discrimination in housing by using data from fair housing audits, a matched-pair technique for comparing the treatment of equllay qualified black and white home buyers. However, we shift the focus from differences in the treatment of paired buyers to agent decisions concerning an individual housing unit using a sample of all houses seen during he 1989 Housing Discrimination study. We estimate a random effect, multinomial logit model to explain a real estate agent's joint decisions concerning whether to show each unit to a black auditor and to a white auditor. We find evidence that agents withhold houses in suburban, integrated neighborhoods from all customers (redlining), that agents' decisions to show houses in integrated neighborhoods are not the same for black and white customers (steering), and that the houses agents show are more likely to deviate from the initial request when the customeris black than when the customer is white. These deviations are consistent with the possibility that agents act upon the belief that some types of transactions are relatively unlikely for black customers (statistical discrimination).

Last Hired, First Fired? Black-White Unemployment and the Business Cycle

Past studies have tested the claim that blacks are the last hired during periods of economic growth and the first fired in recessions by examining the movement of relative unemployment rates over the business cycle. Any conclusion drawn from this type of analysis must be viewed as tentative because the cyclical movements in the underlying transitions into and out of unemployment are not examined. Using Current Population Survey data matched across adjacent months from 1989 to 2004, this paper examines labor market transitions for prime age males to test this hypothesis. Considerable evidence is presented that blacks are the first fired as the business cycle weakens. However, no evidence is found that blacks are the last hired. Instead, blacks are initially hired from the ranks of the unemployed early in the business cycle and later are drawn from non-participation. Narrowing of the racial unemployment gap near the peak of the business cycle is driven by a reduction in the rate of job loss for blacks rather than increases in hiring. There is also evidence that residual differences in the racial unemployment gap vary systematically over the business cycle in a manner consistent with discrimination being more evident in the economy at times when its cost is lower.