Base complementarity in helix 2 of the central pseudoknot in 16S rRNA is essential for ribosome functioning.

Helix 2 of the central pseudoknot structure in Escherichia coli 16S rRNA is formed by a long-distance interaction between nt 17-19 and 918-916, resulting in three base pairs: U17-A918, C18-G917and A19-U916. Previous work has shown that disruption of the central base pair abolishes ribosomal activity. We have mutated the first and last base pairs and tested the mutants for their translational activity in vivo , using a specialized ribosome system. Mutations that disrupt Watson-Crick base pairing result in strongly impaired translational activity. An exception is the mutation U916-->G, creating an A.G pair, which shows almost no decrease in activity. Mutations that maintain base complementarity have little or no impact on translational efficiency. Some of the introduced base pair substitutions substantially alter the stability of helix 2, but this does not influence ribosome functioning, neither at 42 nor at 28 degrees C. Therefore, our results do not support models in which the pseudoknot is periodically disrupted. Rather, the central pseudoknot structure is suggested to function as a permanent structural element necessary for proper organization in the center of the 30S subunit.     

Menarcheal age and subsequent patterns of family formation

Abstract

We examine whether age at menarche affects age at first marriage or first birth using two samples of U.S. women. Data are drawn from the Tremin Trust, a longitudinal study of menstrual cycles that recruited white women who were students at the University of Minnesota and from a survey of a nationally representative sample of white women born between 1900 and 1910. Regression models with cubic splines were used to analyze the relationship between age at menarche and age at first marriage. Cox proportional hazard models were used to examine the effect of age at menarche on the interval between marriage and first birth. Unlike earlier work, we found that once secular trends in both age at marriage and age at menarche were taken into account, there was no evidence that age at menarche affects either age at marriage or the timing of first births in these U.S. women.     

Menarcheal age and subsequent patterns of family formation

We examine whether age at menarche affects age at first marriage or first birth using two samples of U.S. women. Data are drawn from the Tremin Trust, a longitudinal study of menstrual cycles that recruited white women who were students at the University of Minnesota and from a survey of a nationally representative sample of white women born between 1900 and 1910. Regression models with cubic splines were used to analyze the relationship between age at menarche and age at first marriage. Cox proportional hazard models were used to examine the effect of age at menarche on the interval between marriage and first birth. Unlike earlier work, we found that once secular trends in both age at marriage and age at menarche were taken into account, there was no evidence that age at menarche affects either age at marriage or the timing of first births in these U.S. women.     

Trends over 5 decades in U.S. occupation-related physical activity and their associations with obesity

Background

The true causes of the obesity epidemic are not well understood and there are few longitudinal population-based data published examining this issue. The objective of this analysis was to examine trends in occupational physical activity during the past 5 decades and explore how these trends relate to concurrent changes in body weight in the U.S.

Methodology/Principal Findings

Analysis of energy expenditure for occupations in U.S. private industry since 1960 using data from the U.S. Bureau of Labor Statistics. Mean body weight was derived from the U.S. National Health and Nutrition Examination Surveys (NHANES). In the early 1960''s almost half the jobs in private industry in the U.S. required at least moderate intensity physical activity whereas now less than 20% demand this level of energy expenditure. Since 1960 the estimated mean daily energy expenditure due to work related physical activity has dropped by more than 100 calories in both women and men. Energy balance model predicted weights based on change in occupation-related daily energy expenditure since 1960 for each NHANES examination period closely matched the actual change in weight for 40–50 year old men and women. For example from 1960–62 to 2003–06 we estimated that the occupation-related daily energy expenditure decreased by 142 calories in men. Given a baseline weight of 76.9 kg in 1960–02, we estimated that a 142 calories reduction would result in an increase in mean weight to 89.7 kg, which closely matched the mean NHANES weight of 91.8 kg in 2003–06. The results were similar for women.

Conclusion

Over the last 50 years in the U.S. we estimate that daily occupation-related energy expenditure has decreased by more than 100 calories, and this reduction in energy expenditure accounts for a significant portion of the increase in mean U.S. body weights for women and men.     

Cost-Effectiveness of Newborn Circumcision in Reducing Lifetime HIV Risk among U.S. Males

Background

HIV incidence was substantially lower among circumcised versus uncircumcised heterosexual African men in three clinical trials. Based on those findings, we modeled the potential effect of newborn male circumcision on a U.S. male''s lifetime risk of HIV, including associated costs and quality-adjusted life-years saved.

Methodology/Principal Findings

Given published estimates of U.S. males'' lifetime HIV risk, we calculated the fraction of lifetime risk attributable to heterosexual behavior from 2005–2006 HIV surveillance data. We assumed 60% efficacy of circumcision in reducing heterosexually-acquired HIV over a lifetime, and varied efficacy in sensitivity analyses. We calculated differences in lifetime HIV risk, expected HIV treatment costs and quality-adjusted life years (QALYs) among circumcised versus uncircumcised males. The main outcome measure was cost per HIV-related QALY saved. Circumcision reduced the lifetime HIV risk among all males by 15.7% in the base case analysis, ranging from 7.9% for white males to 20.9% for black males. Newborn circumcision was a cost-saving HIV prevention intervention for all, black and Hispanic males. The net cost of newborn circumcision per QALY saved was $87,792 for white males. Results were most sensitive to the discount rate, and circumcision efficacy and cost.

Conclusions/Significance

Newborn circumcision resulted in lower expected HIV-related treatment costs and a slight increase in QALYs. It reduced the 1.87% lifetime risk of HIV among all males by about 16%. The effect varied substantially by race and ethnicity. Racial and ethnic groups who could benefit the most from circumcision may have least access to it due to insurance coverage and state Medicaid policies, and these financial barriers should be addressed. More data on the long-term protective effect of circumcision on heterosexual males as well as on its efficacy in preventing HIV among MSM would be useful.     

Towards a triple bottom-line sustainability assessment of the U.S. construction industry

Purpose

The construction industry has considerable impacts on the environment, economy, and society. Although quantifying and analyzing the sustainability implications of the built environment is of great importance, it has not been studied sufficiently. Therefore, the overarching goal of this study is to quantify the overall environmental, economic, and social impacts of the U.S. construction sectors using an economic input–output-based sustainability assessment framework.

Methods

In this research, the commodity-by-industry supply and use tables published by the U.S. Bureau of Economic Analysis, as part of the International System of National Accounts, are merged with a range of environmental, economic, and social metrics to develop a comprehensive sustainability assessment framework for the U.S. construction industry. After determining these sustainability assessment metrics, the direct and indirect sustainability impacts of U.S construction sectors have been analyzed from a triple bottom-line perspective.

Results

When analyzing the total sustainability impacts by each construction sector, “Residential Permanent Single and Multi-Family Structures" and "Other Non-residential Structures" are found to have the highest environmental, economic, and social impacts in comparison with other construction sectors. The analysis results also show that indirect suppliers of construction sectors have the largest sustainability impacts compared with on-site activities. For example, for all U.S. construction sectors, on-site construction processes are found to be responsible for less than 5 % of total water consumption, whereas about 95 % of total water use can be attributed to indirect suppliers. In addition, Scope 3 emissions are responsible for the highest carbon emissions compared with Scopes 1 and 2. Therefore, using narrowly defined system boundaries by ignoring supply chain-related impacts can result in underestimation of triple bottom-line sustainability impacts of the U.S. construction industry.

Conclusions

Life cycle assessment (LCA) studies that consider all dimensions of sustainability impacts of civil infrastructures are still limited, and the current research is an important attempt to analyze the triple bottom-line sustainability impacts of the U.S. construction sectors in a holistic way. We believe that this comprehensive sustainability assessment model will complement previous LCA studies on resource consumption of U.S. construction sectors by evaluating them not only from environmental standpoint, but also from economic and social perspectives.     

The Relationship of Ethnicity,Socioeconomic Factors,and Overweight in U.S. Adolescents

Objective: To examine the extent to which race/ethnic differences in income and education account for sex‐specific disparities in overweight prevalence in white, African American, Hispanic, and Asian U.S. teens. Research Methods and Procedures: We used nationally representative data collected from 13,113 U.S. adolescents enrolled in the National Longitudinal Study of Adolescent Health. Logistic regression models were used to examine the relationship of family income and parental education to overweight prevalence (body mass index ≥ 85th percentile of age and sex‐specific cutoff points from the 2000 Centers for Disease Control and Prevention/National Center for Health Statistics growth charts). In addition, we used coefficients from our logistic regression models to project the effects on overweight prevalence of equalizing the socioeconomic status (SES) differences between race/ethnic groups. Results: Keeping adolescents in their same environments and changing only family income and parental education had a limited effect on the disparities in overweight prevalence. Ethnicity‐SES‐overweight differences were greater among females than males. Given that overweight prevalence decreased with increasing SES among white females and remained elevated and even increased among higher SES African‐American females, African‐American/white disparity in overweight prevalence increased at the highest SES. Conversely, disparity was lessened at the highest SES for white, Hispanic, and Asian females. Among males, disparity was lowest at the average SES level. Discussion: One cannot automatically assume that the benefits of increased SES found among white adults will transfer to other gender‐age‐ethnic groups. Our findings suggest that efforts to reduce overweight disparities between ethnic groups must look beyond income and education and focus on other factors, such as environmental, contextual, biological, and sociocultural factors.     

Genetic diversity in Eastern U.S. soft winter wheat (Triticum aestivum L. em. Thell.) based on RFLPs and coefficients of parentage

 Genetic diversity in a set of 11 red and 11 white wheat lines from the Eastern U.S. soft wheat germplasm pool was measured using restriction fragment length polymorphism (RFLP) assay and coefficients of parentage (COP) analysis. On average, 78% of all bands revealed by three enzymes with 48 RFLP clones were monomorphic. Average pairwise genetic similarity (GS) was 0.97 when data from all enzymes were pooled. Probe Polymorphic Information Content (PIC) indexes ranged from 0 to 0.73 with a mean of 0.2. Fewer than 55% of the probes revealed any polymorphism. The frequency of polymorphism in the Eastern U.S. soft white winter (SWW) wheat gene pool was much lower than that observed in the Eastern U.S. soft red winter (SRW) wheat gene pool. SWW lines formed a single group on a dendrogram based on cluster analysis of RFLP-derived GS estimates, while SRW lines did not form a single group. COP values for all pairs of the Eastern U.S. soft wheat lines ranged from 0.02 to 0.9 with a mean of 0.21. SWW wheat lines traced to 53 ancestral lines and had an average COP of 0.51. The SRW wheat gene pool had more complex parentages (mean COP=0.15 and a total of 65 ancestral lines). COPs were correlated with RFLP-based GS for all line pairs (r=0.73, P<0.01). However, correlations between the two similarity measures were substantially lower when the SRW and SWW wheat gene pools were considered individually (r values of 0.23 and 0.28, respectively). The actual GS among unrelated lines in the U.S. Eastern soft wheat gene pool appears to be higher than that observed for unrelated landraces from Southwest Asia (0.96 vs. 0.905), suggesting that the ancestral landrace parents of this gene pool were themselves drawn from a base population where inbreeding, i.e., F, was greater than zero. Received:18 April 1996 / Accepted: 6 September 1996     

Scientific Imaginaries and Ethical Plateaus in Contemporary U.S. Toxicology

This article contributes to a growing literature in the anthropology of science, focusing on contemporary U.S. toxicology and the development of "toxicogenomics." Toxicogenomics research aims to understand impacts of environmental stressors at the genetic level and to create a "systems toxicology" that combines different kinds of biological data for holistic understanding. Toxicologists are challenged to deal with greater and greater complexity while fulfilling their historic mission of producing results relevant to regulatory, legal, and clinical decision making. Although there is now a robust body of anthropological work on the sciences—in practice, as sites of cultural production, and as cultural and political-economic forces in a variety of domains—a relatively underdeveloped theme is subject formation within the sciences. This article directs ethnographic attention toward understanding how scientific imaginaries take shape and interpolate technical, biomaterial, political-economic, social, cultural, and ethical elements. We map such efforts in contemporary toxicogenomics as an instance of "civic science."     

Comparative study of the yield of T-2 toxic produced by Fusarium poae,F. sporotrichioides and F. sporotrichioides var. tricinctum strains from different sources

Eleven strains of Fusarium poae and F. sporotrichioides from the U.S.S.R. and 7 strains of these species and one of F. sporotrichioides var. tricinctum from U.S.A. and France have been compared as to their capacity to yield T-2 toxin. The presence of this toxin was confirmed by thin layer chromatography, gas liquid chromatography and mass spectroscopy. The strains which came from the U.S.S.R. and were originally involved in causing Alimentary Toxic Aleukia (ATA), produced several times more T-2 toxin than the others. We assume that the ability of the U.S.S.R. strains to produce much more T-toxin is due to the different ecological conditions under which they were first isolated. The remarkable maintenance of so high a level of toxin production over more than 30 years of culturing is worthy of note.This work was partly supported by the Joint Research Fund of the Hebrew University and Hadassah.     

Historical U.S. Residential Coal Use and Female Lung Cancer Mortality

Recent ecological and case-control studies have indicated elevated lung cancer mortality (LCM) associated with bituminous “smoky” coal (BC) use in China, but no similar study has been conducted using U.S. populations. Early-to-mid 20^th century U.S. county-level consumption of BC for home heating was examined in relation to age-specific LCM, focusing on mortality in white women aged 40+ vs. 60+ years (among whom ～11% vs. ～5% ever smoked, respectively) during 1950 to 1954. To limit potential confounding due to variations in housing characteristics associated with counties where most vs. few homes used coal for heating, this study focused on domestic BC consumption only in 640 counties in which >75% of homes used coal for heating in 1940. County-level data on domestic net tons of BC consumed per capita for the year 1918 were used to estimate lifetime residential exposure to BC smoke, and analyses focused on a 539-county subset for which estimated BC use remained fairly constant between 1918 and 1940. Significantly positive ecological associations were found between BC use and LCM risk in U.S. white women dying in 1950 to 1954 at age 40+ or 60+ y, after adjusting for age and combinations of 20 socio-demographic/geoclimatic variates. The apparent associations suggest that lifetime exposure to residential BC-combustion smoke may have increased LCM risk by about 25% to 50% among relatively highly exposed U.S. women. While these results must viewed in the context of the inherent limitations of any ecological study design, their consistency with results from studies on Chinese women suggests that some risk reduction might be achieved by increased (or universal) application of inexpensive measures to reduce or eliminate any indoor coal smoke in U.S. homes.     

Structural determinants of childlessness: A nonrecursive analysis of 1970 U.S. rates

Abstract

This study tests two theories accounting for observed relationships between U.S. rates of childlessness and sociodemographic characteristics using data on Black and white women aged 30–44 from the 1970 U.S. census. Traditional theory sees the observed correlations as spuriously caused by involuntary sterility, while voluntaristic theory interprets the associations as evidence of influences on the decisions of fecund couples to remain childless. We examine the two positions by estimating and then comparing the aggregate causal structures of childless rates and cumulative fertility rates of women with proven fecundity. The traditional approach expects little if any relationship, while the voluntaristic approach predicts high similarity between the two estimated structures. Results support the voluntaristic position and thus offer indirect substantiation of the voluntaristic theory of areal variation in childless rates.     

Life Years Lost Associated with Obesity-Related Diseases for U.S. Non-Smoking Adults

The objectives of this paper are to predict life years lost associated with obesity-related diseases (ORDs) for U.S. non-smoking adults, and to examine the relationship between those ORDs and mortality. Data from the National Health Interview Survey, 1997–2000, were used. We employed mixed proportional hazard models to estimate the association between those ORDs and mortality and used simulations to project life years lost associated with the ORDs. We found that obesity-attributable comorbidities are associated with large decreases in life years and increases in mortality rates. The life years lost associated with ORDs is more marked for younger adults than older adults, for blacks than whites, for males than females, and for the more obese than the less obese. Using U.S. non-smoking adults aged 40 to 49 years as an example to illustrate percentage of the life years lost associated with ORDs, we found that the mean life years lost associated with ORDs for U.S. non-smoking black males aged 40 to 49 years with a body mass index above 40 kg/m² was 5.43 years, which translates to a 7.5% reduction in total life years. White males of the same age range and same degree of obesity lost 5.23 life years on average – a 6.8% reduction in total life years, followed by black females (5.04 years, a 6.5% reduction in life years), and white females (4.7 years, a 5.8% reduction in life years). Overall, ORDs increased chances of dying and lessened life years by 0.2 to 11.7 years depending on gender, race, BMI classification, and age.     

Widening of socioeconomic inequalities in U.S. death rates, 1993-2001

Background

Socioeconomic inequalities in death rates from all causes combined widened from 1960 until 1990 in the U.S., largely because cardiovascular death rates decreased more slowly in lower than in higher socioeconomic groups. However, no studies have examined trends in inequalities using recent US national data.

Methodology/Principal Findings

We calculated annual age-standardized death rates from 1993–2001 for 25–64 year old non-Hispanic whites and blacks by level of education for all causes and for the seven most common causes of death using death certificate information from 43 states and Washington, D.C. Regression analysis was used to estimate annual percent change. The inequalities in all cause death rates between Americans with less than high school education and college graduates increased rapidly from 1993 to 2001 due to both significant decreases in mortality from all causes, heart disease, cancer, stroke, and other conditions in the most educated and lack of change or increases among the least educated. For white women, the all cause death rate increased significantly by 3.2 percent per year in the least educated and by 0.7 percent per year in high school graduates. The rate ratio (RR) comparing the least versus most educated increased from 2.9 (95% CI, 2.8–3.1) in 1993 to 4.4 (4.1–4.6) in 2001 among white men, from 2.1 (1.8–2.5) to 3.4 (2.9–3–9) in black men, and from 2.6 (2.4–2.7) to 3.8 (3.6–4.0) in white women.

Conclusion

Socioeconomic inequalities in mortality are increasing rapidly due to continued progress by educated white and black men and white women, and stable or worsening trends among the least educated.     

Forecasting the obesity epidemic in the aging U.S. population

Objective: The objective was to forecast BMI distribution in the U.S. population along with demographic changes based on past race‐, sex‐, and birth cohort‐specific secular trends. Research Methods and Procedures: We compiled data from 44,184 subjects from 4 National Health and Nutrition Examination Surveys (NHANES; 1971 to 2004). By race and sex, we fit regression models to create smoothed mean BMI curves by age for 1970 to 2010. Linking corresponding birth cohorts across age‐ and year‐specific mean BMI projections, we estimated the trajectory of relative BMI throughout each cohort's lifetime. These projections were validated using actual cohorts in the Nurses’ Health Study and Health Professionals Follow‐up Study. Combined with U.S. census, we predicted BMI distributions in 2010 and examined the joint impact of the obesity epidemic and population aging. Results: BMI secular trends in the past 3 decades differ significantly by birth cohort, sex, and race. If these trends continue, the prevalence of obesity is expected to reach 35%, 36%, 33%, and 55% in 2010 among white men, white women, black men, and black women, respectively, far from the Healthy People 2010 goal of 15%. Such forecasts translate into 9.3 million more obese adults 20 to 74 years of age than in 2000, 8.3 million of whom would be 50 years of age or older, and 8.5 million of whom would be white. The mean age among obese men and women is also expected to rise from 47 to 49 years among whites and from 43 to 44 years among blacks. Discussion: As the baby boom generation approaches retirement age, the continuing obesity epidemic signals a likely expansion in the population with obesity‐related comorbidities. A framework to combine BMI and demographic trends is essential in evaluating the burden and disparity associated with the epidemic in the aging U.S. population.     

Does the Functional Form of the Association Between Education and Mortality Differ by U.S. Region?

To understand the education–mortality association among U.S. adults, recent studies have documented its national functional form. However, the functional form of education–mortality relationship may vary across geographic contexts. The four U.S. Census regions differ considerably in their social and economic policies, employment opportunities, income levels, and other factors that may affect how education lowers the risk of mortality. Thus, we documented regional differences in the functional form of the education–mortality association and examined the role of employment and income in accounting for regional differences. We used data on non-Hispanic white adults (2,981,672, person years) aged 45–84 in the 2000–2009 National Health Interview Survey, with Linked Mortality File through 2011 (37,598 deaths) and estimated discrete-time hazard models. The functional form of education and adult mortality was best characterized by credentialism in the Midwest, Northeast, and for Western men. For Western women, the association was linear, consistent with the human capital model. In the South, we observed a combination of mechanisms, with mortality risk declining with each year of schooling and a step change with high school graduation, followed by steeper decline thereafter. Our work adds to the increasing body of research that stresses the importance of contexts in shaping the education–mortality relationship.     

Comparative PRNP genotyping of U.S. cattle sires for potential association with BSE

The recent discovery of significant associations between bovine spongiform encephalopathy (BSE) susceptibility in German cattle and the frequency distributions of insertion/deletion (indel) polymorphisms within the bovine PRNP gene prompted an evaluation of 132 commercial U.S. artificial insemination (AI) sires from 39 breeds. Forward primer sequences from published primer sets targeting indels within the putative bovine PRNP promoter, intron 1, and the 3 UTR (untranslated region) were synthesized with unique 5 fluorescent labels and utilized to develop a rapid multiplexed PCR assay for identifying BSE-associated indels as well as facilitating polymorphism analyses and/or marker-assisted selection. Significant differences (p < 0.05 all tests) were detected between the frequencies of bovine PRNP promoter alleles for 48 healthy German cattle previously described and 132 commercial U.S. cattle sires. The frequency of the 23-bp promoter allele observed for commercial U.S. cattle sires strongly resembled that recently described for 43 BSE-affected German cattle. No significant difference (p=0.051) was detected between the distributions of promoter genotypes for healthy German cattle and our panel of commercial U.S. cattle sires. Interestingly, significant differences (p < 0.01; p < 0.02) were also noted between the frequencies and distributions of intron 1 alleles and genotypes, respectively, for BSE-affected German cattle and our panel of U.S. cattle sires. No significant allelic or genotypic differences were detected for the 14-bp 3 UTR indel for any given comparison between German cattle and commercial U.S. cattle sires.     

"Drink Milk for Fitness": The Cultural Politics of Human Biological Variation and Milk Consumption in the United States

Cow's milk is accorded a high cultural value in the contemporary United States. Its white color, association with the maternal and the pastoral, and repeated mention in the Bible add positive symbolic weight to this major national agricultural commodity. Thus, it comes as no surprise that influential policy-making institutions in the United States recommend milk consumption for all U.S. groups. This is despite variation in adult populations' abilities to digest milk, which has been documented by biological anthropologists. This article assesses various U.S. "stories" about milk consumption and its relationship to biological variation against the biological anthropological explanation of variation in lactase activity/lactose tolerance. Many of these serve as normalizing discourses that ultimately pathologize biological difference and may undermine the dietary traditions of some ethnic groups. In particular, the close relationship between government and the dairy industry leads to policies that fail to seriously consider variation in digestive physiology among the diverse U.S. populations.     

A Gifted Amateur: The Case of George Washington Ellis

George Washington Ellis published Negro Culture in West Africa in 1914 in response to the social gospel prophets' racist and stereotypical perspectives of West Africa and Africans. In so doing. Ellis attempted to shift the discourse from one that emphasized African barbarism to one that repudiated the idea of African inferiority. Unwittingly, however, Ellis preached a brand of romantic racialism—a benign doctrine that was commonplace in the racial discourse of African American elites at the Turn of the Century. Asa consequence, his loyalties were divided between 19th-century ethnological science and the "new ethnology" of Franz Boas. [Keywords: George Washington Ellis, history of racism, antiracism, African American anthropology, social gospel prophets]     

Claims of potential expansion throughout the U.S. by invasive python species are contradicted by ecological niche models

Background

Recent reports from the United States Geological Survey (USGS) suggested that invasive Burmese pythons in the Everglades may quickly spread into many parts of the U.S. due to putative climatic suitability. Additionally, projected trends of global warming were predicted to significantly increase suitable habitat and promote range expansion by these snakes. However, the ecological limitations of the Burmese python are not known and the possible effects of global warming on the potential expansion of the species are also unclear.

Methodology/Principal Findings

Here we show that a predicted continental expansion is unlikely based on the ecology of the organism and the climate of the U.S. Our ecological niche models, which include variables representing climatic extremes as well as averages, indicate that the only suitable habitat in the U.S. for Burmese pythons presently occurs in southern Florida and in extreme southern Texas. Models based on the current distribution of the snake predict suitable habitat in essentially the only region in which the snakes are found in the U.S. Future climate models based on global warming forecasts actually indicate a significant contraction in suitable habitat for Burmese pythons in the U.S. as well as in their native range.

Conclusions/Significance

The Burmese python is strongly limited to the small area of suitable environmental conditions in the United States it currently inhabits due to the ecological niche preferences of the snake. The ability of the Burmese python to expand further into the U.S. is severely limited by ecological constraints. Global warming is predicted to significantly reduce the area of suitable habitat worldwide, underscoring the potential negative effects of climate change for many species.