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Groundwater age, defined as the time since recharge, is useful for estimating groundwater renewal rates. Radiocarbon (14C) activity has been widely applied for groundwater age dating since the 1950s. However, this approach can be complicated by other 14C-free carbon sources, which dilute the 14C content at the time of groundwater recharge. Several corrective models have been introduced to determine the dilution factor using carbon isotopes and chemical mass balances, but these models do not account for the influence of deep crust and/or mantle (endogenic) carbon sources and are hence not applicable for dating groundwater affected by endogenic CO2. Therefore, we developed a new 14C groundwater dating model including three carbon end members (biogenically derived sedimentary carbon, carbonate carbon, and deep crust and/or mantle carbon) to quantify the dilution factor. This model was tested by age dating groundwater samples from the United States that were influenced by endogenic carbon (based on their d13C value), showing that the conventional method overestimated the 14C apparent age by ~19% on average. The average uncertainty for the conventional and new method is approximately 1.58% and 11.2%, respectively. The new method proposed here can be applied to groundwater age dating in other regions where aquifers are influenced by endogenic CO2. However, its application requires a priori identification of local geological, hydrogeological, and geochemical conditions. [ABSTRACT FROM AUTHOR]

Few genome-wide association studies (GWAS) of type 2 diabetes (T2D) have been conducted in U.S. Hispanics/Latinos of diverse backgrounds who are disproportionately affected by diabetes. We conducted a GWAS in 2,499 T2D case subjects and 5,247 control subjects from six Hispanic/Latino background groups in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Our GWAS identified two known loci (TCF7L2 and KCNQ1) reaching genome-wide significance levels. Conditional analysis on known index single nucleotide polymorphisms (SNPs) indicated an additional independent signal at KCNQ1, represented by an African ancestry-specific variant, rs1049549 (odds ratio 1.49 [95% CI 1.27-1.75]). This association was consistent across Hispanic/Latino background groups and replicated in the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium. Among 80 previously known index SNPs at T2D loci, 66 SNPs showed consistency with the reported direction of associations and 14 SNPs significantly generalized to the HCHS/SOL. A genetic risk score based on these 80 index SNPs was significantly associated with T2D (odds ratio 1.07 [1.06-1.09] per risk allele), with a stronger effect observed in nonobese than in obese individuals. Our study identified a novel independent signal suggesting an African ancestry-specific allele at KCNQ1 for T2D. Associations between previously identified loci and T2D were generally shown in a large cohort of U.S. Hispanics/Latinos. [ABSTRACT FROM AUTHOR]

Objective: Previous US-based economic models of noninvasive tests for diagnosis of Helicobacter pylori infection did not consider patient adherence or downstream costs of continuing infection. This analysis evaluated the long-term cost-effectiveness of the urea breath test (UBT), fecal antigen test (FAT), and serology for diagnosis of H. pylori infection after incorporating information regarding test adherence. Materials and methods: A decision-analytic model incorporating adherence information evaluated the cost-effectiveness of the UBT, FAT, and serology for diagnosis of H. pylori infection. Positive test results led to first-line triple therapy; no further action was taken for nonadherence or negative results. Excess lifetime costs and reduced quality-adjusted life-years (QALYs) were estimated for patients with continuing H. pylori infection. Results: In the base-case scenario with estimated adherence rates of 86%, 48%, and 86% for the UBT, monoclonal FAT, and serology, respectively, corresponding expected total costs were US$424.99, $466.41, and $404.98/patient. Test costs were higher for the UBT, but were fully or partially offset by higher excess lifetime costs for the monoclonal FAT and serology. The QALYs gained/patient with the UBT vs monoclonal FAT and serology were 0.86 and 0.27, respectively. The UBT was dominant vs the monoclonal FAT, leading to lower costs and higher QALYs; the UBT was cost-effective vs serology (incremental cost/QALY gained $74). Conclusion: Based on a comprehensive modeled analysis that included consideration of patient test adherence and long-term consequences resulting from continuing H. pylori infection, the UBT provided the greatest economic value among noninvasive tests for diagnosis of H. pylori infection, because of high patient adherence and excellent test performance. [ABSTRACT FROM AUTHOR]

Summarizing the status of drugs in the market and examining the trend of drug research and development is important in drug discovery. In this study, we compared the drug targets and the market sales of the new molecular entities approved by the U.S. Food and Drug Administration from January 2000 to December 2009. Two networks, namely, the target-target and drug-drug networks, have been set up using the network analysis tools. The multi-target drugs have much more potential, as shown by the network visualization and the market trends. We discussed the possible reasons and proposed the rational strategies for drug research and development in the future. [ABSTRACT FROM AUTHOR]

This paper brings together the findings of the previous papers in this volume and makes comparisons between the findings from each of the four regions considered. The findings of these comparisons suggest that there are particular characteristics of effective teachers and teaching in mathematics that can be ascribed to Eastern cultures and some other characteristics that can be best ascribed to Western cultures. However, perhaps more strikingly, there are many similarities in the ways in which teachers from the four regions see effective mathematics teaching and learning. [ABSTRACT FROM AUTHOR]

This study investigates US teachers' cultural beliefs concerning effective mathematics teaching using semi-structured interviews with 11 experienced teachers. For US teachers, effective teaching is student-centered. Cognitively appropriate mathematical content should be understood through many hands-on activities that allow students to explore by themselves the relationship between mathematical knowledge and their life experiences. Correspondingly, the US teachers view an effective teacher as a facilitator who is sensitive to student social and cognitive needs and is skillful at organizing collaborative learning. The result of this study helps researchers and educators understand the student-centered learning model in US classrooms. [ABSTRACT FROM AUTHOR]

Stocks of products in use are the pivotal engines that drive anthropogenic metal cycles: They support the lives of people by providing services to them; they are sources for future secondary resources (scrap); and demand for in-use stocks generates demand for metals. Despite their great importance and their impacts on other parts of the metal cycles and the environment, the study of in-use stocks has heretofore been widely neglected. Here we investigate anthropogenic and geogenic iron stocks in the United States (U.S.) by analyzing the iron cycle over the period 1900–2004. Our results show the following. (i) Over the last century, the U.S. iron stock in use increased to 3,200 Tg (million metric tons), which is the same order of magnitude as the remaining U.S. iron stock in identified ores. On a global scale, anthropogenic iron stocks are less significant compared with natural ores, but their relative importance is increasing. (ii) With a perfect recycling system, the U.S. could substitute scrap utilization for domestic mining. (iii) The per-capita in-use iron stock reached saturation at 11–12 metric tons in ≈1980. This last finding, if applicable to other economies as well, could allow a significant improvement of long-term forecasting of steel demand and scrap availability in emerging market economies and therefore has major implications for resource sustainability, recycling technology, and industrial and governmental policy. [ABSTRACT FROM AUTHOR]

This article examines effects of monetary policy surprises on returns, volatilities, trading volumes, and bid–ask spread of two equity ETFs, the S&P 500 SPY fund and the S&P 400 MDY fund. The policy surprises are measured by both surprises in the federal funds rate target changes and surprises in the future direction of the Federal Reserve monetary policy. The results show that there is an overreaction of the SPY to the federal funds rate target surprise in the first 5 minutes' trading and that both the SPY and the MDY returns, volatilities, trading volumes, and bid–ask spread react more strongly to surprise cuts than to surprise increases in the federal funds rate target. Quantitatively, after 45 minutes, an unanticipated 25-basis-point cut in the federal funds rate target is associated with an increase of 1.2 and 1.6% in the SPY and the MDY, respectively, while an unanticipated 25-basis-point decline (or rise) in the four-quarter-ahead eurodollar futures rate is associated with an increase (or decrease) of 0.71 and 0.40% in the SPY and the MDY, respectively. Further evidence also suggests that the market reacts more strongly to surprises in the future direction of monetary policy during the monetary tightening period and that the impact of monetary policy surprises depends on their sizes. © 2006 Wiley Periodicals, Inc. Jrl Fut Mark 26:959–995, 2006 [ABSTRACT FROM AUTHOR]

This article suggests that the logistic growth equation is the model underlying media diffusion. The logistic is shown to be a good fit to the diffusion of U.S. communication media such as radio, TV, cable, VCR, and the home computer. This article proposes that the r and K parameters of the logistic can be interpreted, respectively, as anticipated gratification utilities and economic conditions. In addition, the results of hypothesis testing showed that step variables representing changes in anticipated gratification utilities were related to the diffusion of cable and the personal computer. A hypothesis predicting a relation between disposable income and diffusion of U.S. communication media was supported only for the personal computer. We believe further research should attempt to measure variables representing r and K at the individual or household level. [ABSTRACT FROM AUTHOR]

Ischemic heart disease resulting from myocardial infarction (MI) is the most prevalent form of heart disease in the United States. Post-MI cardiac remodeling is a multifaceted process that includes activation of fibroblasts and a complex immune response. T-regulatory cells (Tregs), a subset of CD4+ T cells, have been shown to suppress the innate and adaptive immune response and limit deleterious remodeling following myocardial injury. However, the mechanisms by which injured myocardium recruits suppressive immune cells remain largely unknown. Here, we have shown a role for Hippo signaling in the epicardium in suppressing the post-infarct inflammatory response through recruitment of Tregs. Mice deficient in epicardial YAP and TAZ, two core Hippo pathway effectors, developed profound post-MI pericardial inflammation and myocardial fibrosis, resulting in cardiomyopathy and death. Mutant mice exhibited fewer suppressive Tregs in the injured myocardium and decreased expression of the gene encoding IFN-γ, a known Treg inducer. Furthermore, controlled local delivery of IFN-γ following MI rescued Treg infiltration into the injured myocardium of YAP/TAZ mutants and decreased fibrosis. Collectively, these results suggest that epicardial Hippo signaling plays a key role in adaptive immune regulation during the post-MI recovery phase. [ABSTRACT FROM AUTHOR]