Understanding the Hydrology of Karst

Determining the nature of water flow and contaminant dispersion in karst requires far more information than can be provided by simple dye traces. Tracing can delineate drainage divides, flow directions, and flow velocities at various stages, but from water management purposes it is also important to determine such variables as groundwater storage, retention times, patterns of convergence and divergence, and response to wet-dry cycles in the soil. These are most significant in the non-conduit portions of the karst aquifer, which supply most wells. Dye tracing can be augmented by hydrograph analysis at various stages, tracing with tagged solid particles or microbes, evaluation of dissolved solids and chemical equilibria, and isotopic analysis. This paper concentrates on some of the uses of chemical equilibria and isotopes. Stable isotopes (e.g. 18O and deuterium) and the various radium isotopes are among the most useful. Ratios among the four radium isotopes (228Ra and 224Ra, with half-lives in years; and 223Ra and 226Ra with half-lives in days) are well suited to karst studies. These techniques are time-consuming and costly, so a full analysis of a karst aquifer is rarely feasible. Instead, it is recommended that selective analyses be made of representative parts of the aquifer, and that they be applied as follows: (1) Develop conceptual models based on field observation, which allow one to anticipate a range of probable scenarios of contaminant transport and remediation. (2) If digital models are used, it is most effective to design simple generalized models in which the boundary conditions are clearly defined, and then to gain insight into real aquifers by noting the differences between the model and field observations. (3) Use field techniques to become familiar with the local hydrology and then apply hydraulic and chemical principles to anticipating contaminant behavior, rather than reacting only to emergencies. These approaches encourage the growth of interpretive skills based on the same scientific principles that govern the origin of caves and karst.</p

Understanding the Hydrology of Karst

Determining the nature of water flow and contaminant dispersion in karst requires far more information than can be provided by simple dye traces. Tracing can delineate drainage divides, flow directions, and flow velocities at various stages, but from water management purposes it is also important to determine such variables as groundwater storage, retention times, patterns of convergence and divergence, and response to wet-dry cycles in the soil. These are most significant in the non-conduit portions of the karst aquifer, which supply most wells. Dye tracing can be augmented by hydrograph analysis at various stages, tracing with tagged solid particles or microbes, evaluation of dissolved solids and chemical equilibria, and isotopic analysis. This paper concentrates on some of the uses of chemical equilibria and isotopes. Stable isotopes (e.g. 18O and deuterium) and the various radium isotopes are among the most useful. Ratios among the four radium isotopes (228Ra and 224Ra, with half-lives in years; and 223Ra and 226Ra with half-lives in days) are well suited to karst studies. These techniques are time-consuming and costly, so a full analysis of a karst aquifer is rarely feasible. Instead, it is recommended that selective analyses be made of representative parts of the aquifer, and that they be applied as follows: (1) Develop conceptual models based on field observation, which allow one to anticipate a range of probable scenarios of contaminant transport and remediation. (2) If digital models are used, it is most effective to design simple generalized models in which the boundary conditions are clearly defined, and then to gain insight into real aquifers by noting the differences between the model and field observations. (3) Use field techniques to become familiar with the local hydrology and then apply hydraulic and chemical principles to anticipating contaminant behavior, rather than reacting only to emergencies. These approaches encourage the growth of interpretive skills based on the same scientific principles that govern the origin of caves and karst.</p

Historical reconstruction of the Atlantic Meridional Overturning Circulation from the ECMWF operational ocean reanalysis

A reconstruction of the Atlantic Meridional Overturning Circulation (MOC) for the period 1959–2006 has been derived from the ECMWF operational ocean reanalysis. The reconstruction shows a wide range of time-variability, including a downward trend. At 26N, both the MOC intensity and changes in its vertical structure are in good agreement with previous estimates based on trans-Atlantic surveys. At 50N, the MOC and strength of the subpolar gyre are correlated at interannual time scales, but show opposite secular trends. Heat transport variability is highly correlated with the MOC but shows a smaller trend due to the warming of the upper ocean, which partially compensates for the weakening of the circulation. Results from sensitivity experiments show that although the time-varying upper boundary forcing provides useful MOC information, the sequential assimilation of ocean data further improves the MOC estimation by increasing both the mean and the time variability

Secondary Sex Ratio among Women Exposed to Diethylstilbestrol in Utero

BACKGROUND. Diethylstilbestrol (DES), a synthetic estrogen widely prescribed to pregnant women during the mid-1900s, is a potent endocrine disruptor. Previous studies have suggested an association between endocrine-disrupting compounds and secondary sex ratio. METHODS. Data were provided by women participating in the National Cancer Institute (NCI) DES Combined Cohort Study. We used generalized estimating equations to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the relation of in utero DES exposure to sex ratio (proportion of male births). Models were adjusted for maternal age, child's birth year, parity, and cohort, and accounted for clustering among women with multiple pregnancies. RESULTS. The OR for having a male birth comparing DES-exposed to unexposed women was 1.05 (95% CI, 0.95-1.17). For exposed women with complete data on cumulative DES dose and timing (33%), those first exposed to DES earlier in gestation and to higher doses had the highest odds of having a male birth. The ORs were 0.91 (95% C, 0.65-1.27) for first exposure at ≥ 13 weeks gestation to < 5 g DES; 0.95 (95% CI, 0.71-1.27) for first exposure at ≥ 13 weeks to ≥ 5 g; 1.16 (95% CI, 0.96-1.41) for first exposure at < 13 weeks to < 5 g; and 1.24 (95% CI, 1.04-1.48) for first exposure at < 13 weeks to ≥ 5 g compared with no exposure. Results did not vary appreciably by maternal age, parity, cohort, or infertility history. CONCLUSIONS. Overall, no association was observed between in utero DES exposure and secondary sex ratio, but a significant increase in the proportion of male births was found among women first exposed to DES earlier in gestation and to a higher cumulative dose.National Cancer Institute (N01-CP-21168, N01-CP-51017, N01-CP-01289

River Flows and Water Wars: Emerging Science for Environmental Decision Making

Real and apparent conflicts between ecosystem and human needs for fresh water are contributing to the emergence of an alternative model for conducting river science around the world. The core of this new paradigm emphasizes the need to forge new partnerships between scientists and other stakeholders where shared ecological goals and river visions are developed, and the need for new experimental approaches to advance scientific understanding at the scales relevant to whole-river management. We identify four key elements required to make this model succeed: existing and planned water projects represent opportunities to conduct ecosystem-scale experiments through controlled river flow manipulations; more cooperative interactions among scientists, managers, and other stakeholders are critical; experimental results must be synthesized across studies to allow broader generalization; and new, innovative funding partnerships are needed to engage scientists and to broadly involve the government, the private sector, and NGOs

Urogenital Abnormalities in Men Exposed to Diethylstilbestrol in Utero: A Cohort Study

Background: Diethylstilbestrol (DES), a synthetic estrogen widely prescribed to pregnant women during the 1940s70s, has been shown to cause reproductive problems in the daughters. Studies of prenatally-exposed males have yielded conflicting results. Methods: In data from a collaborative follow-up of three U.S. cohorts of DES-exposed sons, we examined the relation of prenatal DES exposure to occurrence of male urogenital abnormalities. Exposure status was determined through review of prenatal records. Mailed questionnaires (1994, 1997, 2001) asked about specified abnormalities of the urogenital tract. Risk ratios (RR) were estimated by Cox regression with constant time at risk and control for year of birth. Results: Prenatal DES exposure was not associated with varicocele, structural abnormalities of the penis, urethral stenosis, benign prostatic hypertrophy, or inflammation/infection of the prostate, urethra, or epididymus. However, RRs were 1.9 (95% confidence interval 1.13.4) for cryptorchidism, 2.5 (1.54.3) for epididymal cyst, and 2.4 (1.54.4) for testicular inflammation/ infection. Stronger associations were observed for DES exposure that began before the 11th week of pregnancy: RRs were 2.9 (1.65.2) for cryptorchidism, 3.5 (2.06.0) for epididymal cyst, and 3.0 (1.75.4) for inflammation/infection of testes. Conclusion: These results indicate that prenatal exposure to DES increases risk of male urogenital abnormalities and that the association is strongest for exposure that occurs early in gestation. The findings support the hypothesis that endocrine disrupting chemicals may be a cause of the increased prevalence of cryptorchidism that has been seen in recent years

Informing the design of a national screening and treatment programme for chronic viral hepatitis in primary care: qualitative study of at-risk immigrant communities and healthcare professionals

n Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise statedThis paper presents independent research funded by the National Institute for Health Research (NIHR) under the Programme Grants for Applied Research programme (RP-PG-1209-10038).

Finding a moral homeground: appropriately critical religious education and transmission of spiritual values

Values-inspired issues remain an important part of the British school curriculum. Avoiding moral relativism while fostering enthusiasm for spiritual values and applying them to non-curricular learning such as school ethos or children's home lives are challenges where spiritual, moral, social and cultural (SMSC) development might benefit from leadership by critical religious education (RE). Whether the school's model of spirituality is that of an individual spiritual tradition (schools of a particular religious character) or universal pluralistic religiosity (schools of plural religious character), the pedagogy of RE thought capable of leading SMSC development would be the dialogical approach with examples of successful implementation described by Gates, Ipgrave and Skeie. Marton's phenomenography, is thought to provide a valuable framework to allow the teacher to be appropriately critical in the transmission of spiritual values in schools of a particular religious character as evidenced by Hella's work in Lutheran schools

Hundreds of variants clustered in genomic loci and biological pathways affect human height

Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P < 0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.