794 research outputs found

    Documenting the Anthropogenic Impact on Ballston Lake New York from a short core using stable isotopes of carbon and nitrogen and trace metals

    Get PDF
    Ballston Lake occupies a portion of an avulsed channel of the Mohawk River between Schenectady and Saratoga Springs, New York. The lake is about 5 km long, generally less than 200m wide, ~8-15m deep, dimictic, with a catchment basin area of ~22km2. Long cores (\u3e8 m) indicate that the lake formed ~13,000 cal yr BP. This study was undertaken to document recent environmental change recorded in the upper portion of sediment in Ballston Lake. Three sediment cores ~40 cm long were acquired from ~8 m water depth at the north end of Ballston Lake (42°57.101’N, 73°51.066’W), and were analyzed for exchangeable metals, magnetic susceptibility, total organic carbon (TOC), total inorganic carbon (TIC), organic carbon to nitrogen ratios (C/N), and stable isotopes of carbon and nitrogen. An age model of the cores was established by correlating a prominent increase in Pb (1882 AD) and the Pb maximum (1970) based on 210Pb dating of cores from nearby lakes (Round Pond and Long Pond). Cu and Zn reflect similar increasing trends at this time, and these increases are likely attributed to industrialization and the burning of fossil fuels throughout the 20th century. 13C values become more negative through time, declining from -29 to -30.5‰, suggesting the organic carbon is more aquatically derived. Percent TOC increases towards the surface of the core demonstrating increased productivity that is unrelated to nitrogen input, as %N and 15N values are relatively constant. Though the data suggests that development around Ballston Lake has had only a minor impact on productivity and pollution, there are apparent changes that occurred in the lake between AD ~1970 and 1981. The increase in TIC and decrease in TOC, 13C values, and grey scale values suggest there was an increase in clastic sediment input into the lake and reduction in terrestrial organic matter input. This event could be caused by the severe drought in New England that occurred in the 1960s, killing vegetation and weakening the erodible surfaces. Ballston Lake should be monitored for anthropogenic pollution in the future, though there has been little anthropogenic impact at this point in time

    Studies of the marine crustal magnetization at intermediate wavelengths

    Get PDF
    The data can be filtered at intermediate wavelengths to provde a data set which complements the satellite fields of MAGSAT, TSS and GRM. The filtered marine data set provides a high resolution data set which is closer to the source bodies than satellite survey data. However, the GRM and TSS could provide the necessary resolution to match the filtered sea surface field. The added resolution determines the nature of crustal magnetizations which give rise to the intermediate wavelength field. It is found that remanent magnetization is an important component over the oceans. Crustal deformation and plate motions result in magnetization vectors which differ significantly from the present day field directions. Induced magnetization or GRM are important components over the oceanic plateaus and spreading centers

    Mendelian randomization with a binary exposure variable: interpretation and presentation of causal estimates

    Get PDF
    Mendelian randomization uses genetic variants to make causal inferences about a modifiable exposure. Subject to a genetic variant satisfying the instrumental variable assumptions, an association between the variant and outcome implies a causal effect of the exposure on the outcome. Complications arise with a binary exposure that is a dichotomization of a continuous risk factor (for example, hypertension is a dichotomization of blood pressure). This can lead to violation of the exclusion restriction assumption: the genetic variant can influence the outcome via the continuous risk factor even if the binary exposure does not change. Provided the instrumental variable assumptions are satisfied for the underlying continuous risk factor, causal inferences for the binary exposure are valid for the continuous risk factor. Causal estimates for the binary exposure assume the causal effect is a stepwise function at the point of dichotomization. Even then, estimation requires further parametric assu

    Effects of a community scorecard on improving the local health system in Eastern Democratic Republic of Congo: qualitative evidence using the most significant change technique.

    Get PDF
    BACKGROUND: More than a decade of conflict has weakened the health system in the Democratic Republic of Congo and decreased its ability to respond to the needs of the population. Community scorecards have been conceived as a way to increase accountability and responsiveness of service providers, but there is limited evidence of their effects, particularly in fragile and conflict-affected contexts. This paper describes the implementation of community scorecards within a community-driven reconstruction project in two provinces of eastern Democratic Republic of Congo. METHODS: Between June 2012 and November 2013, 45 stories of change in the health system were collected from village development committee, health committee, community members (20 men and 18 women) and healthcare providers (n = 7) in 25 sites using the Most Significant Change technique. Stories were analyzed qualitatively for content related to the types and mechanisms of change observed. RESULTS: The most salient changes were related to increased transparency and community participation in health facility management, and improved quality of care. Quality of care included increased access to services, improved patient-provider relationships, improved performance of service providers, and improved maintenance of physical infrastructure. Changes occurred through many different mechanisms including provider actions in response to information, pressure from community representatives, or supervisors; and joint action and improved collaboration by health facility committees and providers. CONCLUSIONS: Although it is often assumed that confrontation is a primary mechanism for citizens to change state-provided services, this study demonstrates that healthcare providers may also be motivated to change through other means. Positive experiences of community scorecards can provide a structured space for interface between community members and the health system, allowing users to voice their opinions and preferences and bridge information gaps for both users and frontline healthcare providers. When solutions to problems identified through the scorecard are locally accessible, users and healthcare providers are able to work together to implement mutually acceptable solutions that improve quality of health services, and make them more responsive to users' needs

    Effects of carrying a pregnancy and of method of delivery on urinary incontinence: a prospective cohort study

    Get PDF
    BACKGROUND: This study was carried out to identify risk factors associated with urinary incontinence in women three months after giving birth. METHODS: Urinary incontinence before and during pregnancy was assessed at study enrolment early in the third trimester. Incontinence was re-assessed three months postpartum. Logistic regression analysis was used to assess the role of maternal and obstetric factors in causing postpartum urinary incontinence. This prospective cohort study in 949 pregnant women in Quebec, Canada was nested within a randomised controlled trial of prenatal perineal massage. RESULTS: Postpartum urinary incontinence was increased with prepregnancy incontinence (adjusted odds ratio [adj0R] 6.44, 95% CI 4.15, 9.98), incontinence beginning during pregnancy (adjOR 1.93, 95% CI 1.32, 2.83), and higher prepregnancy body mass index (adjOR 1.07/unit of BMI, 95% CI 1.03,1.11). Caesarean section was highly protective (adjOR 0.27, 95% CI 0.14, 0.50). While there was a trend towards increasing incontinence with forceps delivery (adjOR 1.73, 95% CI 0.96, 3.13) this was not statistically significant. The weight of the baby, episiotomy, the length of the second stage of labour, and epidural analgesia were not predictive of urinary incontinence. Nor was prenatal perineal massage, the randomised controlled trial intervention. When the analysis was limited to women having their first vaginal birth, the same risk factors were important, with similar adjusted odds ratios. CONCLUSIONS: Urinary incontinence during pregnancy is extremely common, affecting over half of pregnant women. Urinary incontinence beginning during pregnancy roughly doubles the likelihood of urinary incontinence at 3 months postpartum, regardless whether delivery is vaginal or by Caesarean section

    Frequency and patterns of early recanalization after vasectomy

    Get PDF
    BACKGROUND: Our understanding of early post-vasectomy recanalization is limited to histopathological studies. The objective of this study was to estimate the frequency and to describe semen analysis patterns of early recanalization after vasectomy. METHODS: Charts displaying serial post-vasectomy semen analyses were created using the semen analysis results from 826 and 389 men participating in a randomized trial of fascial interposition (FI) and an observational study of cautery, respectively. In the FI trial, participants were randomly allocated to vas occlusion by ligation and excision with or without FI. In the cautery study, sites used their usual cautery occlusion technique, two with and two without FI. Presumed early recanalization was based on the assessment of individual semen analysis charts by three independent reviewers. Discrepancies were resolved by consensus. RESULTS: Presumed early recanalization was characterized by a very low sperm concentration within two weeks after vasectomy followed by return to large numbers of sperm over the next few weeks. The overall proportion of men with presumed early recanalization was 13% (95% CI 12%–15%). The risk was highest with ligation and excision without FI (25%) and lowest for thermal cautery with FI (0%). The highest proportion of presumed early recanalization was observed among men classified as vasectomy failures. CONCLUSION: Early recanalization, occurring within the first weeks after vasectomy, is more common than generally recognized. Its frequency depends on the occlusion technique performed

    The effects of childbirth on the pelvic-floor

    Get PDF
    Basically, vaginal delivery is associated with the risk of pelvic floor damage. The pelvic floor sequelae of childbirth includes anal incontinence, urinary incontinence and pelvic organ prolapse. Pathophysiology, incidence and risk factors for the development of the respective problems are reviewed. Where possible, recommendations for reducing the risk of pelvic floor damage are given
    • …
    corecore