Warming the early Earth - CO2 reconsidered

Despite a fainter Sun, the surface of the early Earth was mostly ice-free. Proposed solutions to this so-called "faint young Sun problem" have usually involved higher amounts of greenhouse gases than present in the modern-day atmosphere. However, geological evidence seemed to indicate that the atmospheric CO2 concentrations during the Archaean and Proterozoic were far too low to keep the surface from freezing. With a radiative-convective model including new, updated thermal absorption coefficients, we found that the amount of CO2 necessary to obtain 273 K at the surface is reduced up to an order of magnitude compared to previous studies. For the late Archaean and early Proterozoic period of the Earth, we calculate that CO2 partial pressures of only about 2.9 mb are required to keep its surface from freezing which is compatible with the amount inferred from sediment studies. This conclusion was not significantly changed when we varied model parameters such as relative humidity or surface albedo, obtaining CO2 partial pressures for the late Archaean between 1.5 and 5.5 mb. Thus, the contradiction between sediment data and model results disappears for the late Archaean and early Proterozoic.Comment: 53 pages, 4 tables, 11 figures, published in Planetary and Space Scienc

Interventions Aimed at Decreasing Obesity in Children Younger Than 2 Years: A Systematic Review

To assess the evidence for interventions designed to prevent or reduce overweight and obesity in children younger than 2 years

The Association of Acculturation and Health Literacy, Numeracy and Health-Related Skills in Spanish-speaking Caregivers of Young Children

Little is known about the relationship among acculturation, literacy, and health skills in Latino caregivers of young children. Latino caregivers of children <30 months seeking primary care at four medical centers were administered measures of acculturation (SASH), functional health literacy (STOFHLA), numeracy (WRAT-3) and health-related skills (PHLAT Spanish). Child anthropomorphics and immunization status were ascertained by chart review. Caregivers (N = 184) with a median age of 27 years (IQR: 23–32) participated; 89.1 % were mothers, and 97.1 % had low acculturation. Lower SASH scores were significantly correlated (P < 0.01) with lower STOFHLA (ρ = 0.21), WRAT-3 (ρ = 0.25), and PHLAT Spanish scores (ρ = 0.34). SASH scores predicted PHLAT Spanish scores in a multivariable linear regression model that adjusted for the age of child, the age and gender of the caregiver, number of children in the family, the type of health insurance of the caregiver, and study site (adjusted β: 0.84, 95 % CI 0.26–1.42, P = 0.005). This association was attenuated by the addition of literacy (adjusted β: 0.66, 95 % CI 0.11–1.21, P = 0.02) or numeracy (adjusted β: 0.50, 95 % CI −0.04–1.04, P = 0.07) into the model. There was no significant association between acculturation and up-to-date child immunizations or a weight status of overweight/obese. Lower acculturation was associated with worse health literacy and diminished ability to perform child health-related skills. Literacy and numeracy skills attenuated the association between acculturation and child health skills. These associations may help to explain some child health disparities in Latino communities

A multivariate hierarchical Bayesian approach to measuring agreement in repeated measurement method comparison studies

Background. Assessing agreement in method comparison studies depends on two fundamentally important components; validity (the between method agreement) and reproducibility (the within method agreement). The Bland-Altman limits of agreement technique is one of the favoured approaches in medical literature for assessing between method validity. However, few researchers have adopted this approach for the assessment of both validity and reproducibility. This may be partly due to a lack of a flexible, easily implemented and readily available statistical machinery to analyse repeated measurement method comparison data. Methods. Adopting the Bland-Altman framework, but using Bayesian methods, we present this statistical machinery. Two multivariate hierarchical Bayesian models are advocated, one which assumes that the underlying values for subjects remain static (exchangeable replicates) and one which assumes that the underlying values can change between repeated measurements (non-exchangeable replicates). Results. We illustrate the salient advantages of these models using two separate datasets that have been previously analysed and presented; (i) assuming static underlying values analysed using both multivariate hierarchical Bayesian models, and (ii) assuming each subject's underlying value is continually changing quantity and analysed using the non-exchangeable replicate multivariate hierarchical Bayesian model. Conclusion. These easily implemented models allow for full parameter uncertainty, simultaneous method comparison, handle unbalanced or missing data, and provide estimates and credible regions for all the parameters of interest. Computer code for the analyses in also presented, provided in the freely available and currently cost free software package WinBUGS

Improved outcome in children with advanced stage B-cell non-Hodgkin's lymphoma (B-NHL): results of the United Kingdom Children Cancer Study Group (UKCCSG) 9002 protocol

From July 1990 to March 1996, 112 children with stage III or IV B-cell non-Hodgkin's lymphoma (B-NHL) with up to 70% FAB L3-type blasts (n= 42) in the bone marrow without central nervous system (CNS) disease were treated on the United Kingdom Children Cancer Study Group (UKCCSG) 9002 protocol (identical to the French LMB 84). The median age was 8.3 years. There were 81 boys and 31 girls. According to the extent of the primary disease, patients were sub-staged into three groups: IIIA with unresectable abdominal tumour (n= 39); IIIB with abdominal multiorgan involvement (n= 57) and IIIX with extra-abdominal primary lymphoma often presenting as pleural effusion (n= 16). Univariate and multivariate analyses were carried out to evaluate the prognostic significance of lactate dehydrogenase (LDH) level at diagnosis, the sub-stage and the time to achieve complete remission (CR). With a median follow up of 48 months (range 12–92), the overall and event free survival (EFS) is 87% (95% confidence interval (CI) 79.2–92.1%) and 83.7% (95% CI 76.3–89.2%) respectively. Six patients (5.4%) never achieved CR, of whom one is alive following high-dose therapy. Eight patients (7.1%) relapsed after achieving CR, three are alive after second-line therapy. There were three early toxic deaths (2.7%), mainly from infection, and one late death from a second cancer. There was no significant difference in EFS according to LDH level at diagnosis, the sub-stage or the time to CR. This study confirms the overall good prognosis and low rate of toxic deaths in patients with advanced B-NHL treated with this intensive regimen. No significant difference in EFS according to the sub-stage, the time to achieve CR or LDH level at diagnosis making it difficult to identify a group that should not receive intensive therapy. © 2000 Cancer Research Campaig

The Association among Literacy, Numeracy, HIV Knowledge and Health-Seeking Behavior: A Population-Based Survey of Women in Rural Mozambique

BACKGROUND: Limited literacy skills are common in the United States (US) and are related to lower HIV knowledge and worse health behaviors and outcomes. The extent of these associations is unknown in countries like Mozambique, where no rigorously validated literacy and numeracy measures exist. METHODS: A validated measure of literacy and numeracy, the Wide Range Achievement Test, version 3 (WRAT-3) was translated into Portuguese, adapted for a Mozambican context, and administered to a cross-section of female heads-of-household during a provincially representative survey conducted from August 8 to September 25, 2010. Construct validity of each subscale was examined by testing associations with education, income, and possession of socioeconomic assets, stratified by Portuguese speaking ability. Multivariable regression models estimated the association among literacy/numeracy and HIV knowledge, self-reported HIV testing, and utilization of prenatal care. RESULTS: Data from 3,557 women were analyzed; 1,110 (37.9%) reported speaking Portuguese. Respondents' mean age was 31.2; 44.6% lacked formal education, and 34.3% reported no income. Illiteracy was common (50.4% of Portuguese speakers, 93.7% of non-Portuguese speakers) and the mean numeracy score (10.4) corresponded to US kindergarten-level skills. Literacy or numeracy was associated (p<0.01) with education, income, age, and other socioeconomic assets. Literacy and numeracy skills were associated with HIV knowledge in adjusted models, but not with HIV testing or receipt of clinic-based prenatal care. CONCLUSION: The adapted literacy and numeracy subscales are valid for use with rural Mozambican women. Limited literacy and numeracy skills were common and associated with lower HIV knowledge. Further study is needed to determine the extent to which addressing literacy/numeracy will lead to improved health outcomes

Helicobacter pylori Seropositivity and Risk of Lung Cancer

Lung cancer is the leading cause of cancer mortality worldwide. Helicobacter pylori (H. pylori) is a risk factor for distal stomach cancer, and a few small studies have suggested that H. pylori may be a potential risk factor for lung cancer. To test this hypothesis, we conducted a study of 350 lung adenocarcinoma cases, 350 squamous cell carcinoma cases, and 700 controls nested within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) cohort of male Finnish smokers. Controls were one-to-one matched by age and date of baseline serum draw. Using enzyme-linked immunosorbent assays to detect immunoglobulin G antibodies against H. pylori whole-cell and cytotoxin-associated gene (CagA) antigens, we calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for associations between H. pylori seropositivity and lung cancer risk using conditional logistic regression. H. pylori seropositivity was detected in 79.7% of cases and 78.5% of controls. After adjusting for pack-years and cigarettes smoked per day, H. pylori seropositivity was not associated with either adenocarcinoma (OR: 1.1, 95% CI: 0.75–1.6) or squamous cell carcinoma (OR: 1.1, 95% CI: 0.77–1.7). Results were similar for CagA-negative and CagA-positive H. pylori seropositivity. Despite earlier small studies suggesting that H. pylori may contribute to lung carcinogenesis, H. pylori seropositivity does not appear to be associated with lung cancer

Neighborhood conditions, diabetes, and risk of lower-body functional limitations among middle-aged African Americans: A cohort study

<p>Abstract</p> <p>Background</p> <p>The relationship between presence of diabetes and adverse neighborhood and housing conditions and their effect on functional decline is unclear. We examined the association of adverse neighborhood (block face) and housing conditions with incidence of lower-body functional limitations among persons with and those without diabetes using a prospective population-based cohort study of 563 African Americans 49-65 years of age at their 2000-2001 baseline interviews.</p> <p>Methods</p> <p>Participants were randomly sampled African Americans living in the St. Louis area (response rate: 76%). Physician-diagnosed diabetes was self reported at baseline interview. Lower-body functional limitations were self reported based on the Nagi physical performance scale at baseline and the three-year follow-up interviews. The external appearance of the block the respondent lived on and five housing conditions were rated by study interviewers. All analyses were done using propensity score methods to control for confounders.</p> <p>Results</p> <p>109 (19.4%) of subjects experienced incident lower-body functional limitations at three-year follow-up. In adjusted analysis, persons with diabetes who lived on block faces rated as fair-poor on each of the five conditions had higher odds (7.79 [95% confidence interval: 1.36-37.55] to 144.6 [95% confidence interval: 4.45-775.53]) of developing lower-body functional limitations than the referent group of persons without diabetes who lived on block faces rated as good-excellent. At least 80 percent of incident lower-body functional limitations was attributable to the interaction between block face conditions and diabetes status.</p> <p>Conclusions</p> <p>Adverse neighborhood conditions appear to exacerbate the detrimental effects on lower-body functioning associated with diabetes.</p

Reduced Plasmodium vivax Erythrocyte Infection in PNG Duffy-Negative Heterozygotes

BACKGROUND: Erythrocyte Duffy blood group negativity reaches fixation in African populations where Plasmodium vivax (Pv) is uncommon. While it is known that Duffy-negative individuals are highly resistant to Pv erythrocyte infection, little is known regarding Pv susceptibility among heterozygous carriers of a Duffy-negative allele (+/−). Our limited knowledge of the selective advantages or disadvantages associated with this genotype constrains our understanding of the effect that interventions against Pv may have on the health of people living in malaria-endemic regions. METHODS AND FINDINGS: We conducted cross-sectional malaria prevalence surveys in Papua New Guinea (PNG), where we have previously identified a new Duffy-negative allele among individuals living in a region endemic for all four human malaria parasite species. We evaluated infection status by conventional blood smear light microscopy and semi-quantitative PCR-based strategies. Analysis of a longitudinal cohort constructed from our surveys showed that Duffy heterozygous (+/−) individuals were protected from Pv erythrocyte infection compared to those homozygous for wild-type alleles (+/+) (log-rank tests: LM, p = 0.049; PCR, p = 0.065). Evaluation of Pv parasitemia, determined by semi-quantitative PCR-based methods, was significantly lower in Duffy +/− vs. +/+ individuals (Mann-Whitney U: p = 0.023). Overall, we observed no association between susceptibility to P. falciparum erythrocyte infection and Duffy genotype. CONCLUSIONS: Our findings provide the first evidence that Duffy-negative heterozygosity reduces erythrocyte susceptibility to Pv infection. As this reduction was not associated with greater susceptibility to Pf malaria, our in vivo observations provide evidence that Pv-targeted control measures can be developed safely