108 research outputs found
Characterization of shallow groundwater in Eocene sediments of Panama Canal Watershed using electrical techniques
This work is focused on the detection of seepages caused by the affluent located in a small area of the Panama Canal Basin during the dry season, and to define the subsurface stratigraphy (Eocene sediments) that characterize this area through a geophysical survey. Two electrical resistivity tomography were developed to identify the extent of infiltration and the nature of the clay layers vertically and laterally, these results were corroborated by a drilling operation in the vicinity of electrical tests and based on this information, established a model for a two-dimensional geoelectric profile in order to compare (i) the pseudo-sections of synthetic and measured apparent electrical resistivity, and (ii) the electrical resistivity tomography as a result of the inversions of such pseudo-sections. The results of electrical resistivity tomography obtained in the two profiles revealed the existence of (i) a surface layer moderately resistant (18-85 ohm.m) with a thickness not exceeding 1,8 m, (ii) an area of high electrical conductivity (3,8 to 10,7 ohm.m) with a thickness not exceeding 9.5 m and (iii) a resistant substratum with electrical resistivity values calculated in excess of 30,1 ohm.m and a range depth ranging from 2 to 11,5 m. The drilling operation in the vicinity of the geophysical tests revealed the presence of clay with varying moisture content and density, and thicknesses that corroborate the results of the geophysical evidence. The two-dimensional geoelectrical model of Profile 1 was established according to the results of electrical resistivity tomography as well as the profile and information of the drilling operation. Based on the results of this study, we conclude that the infiltrations generated by the affluent in this part of the Isthmus of Panama are very important, even in periods when precipitation levels are
Chronic bilateral heel pain in a child with Sever disease: case report and review of literature
We are presenting a case report of a 10-year-old male with a 1 year history of bilateral heel pain. Sever disease is self limiting condition of calcaneal apophysis. It is the most common cause of heel pain in the growing child. There is no documented case of this condition in this region. This case highlights the clinical features of this self limiting disorder as seen in this patient and reviews the current literature
The association between exaggeration in health related science news and academic press releases: retrospective observational study
Objective To identify the source (press releases or news) of distortions, exaggerations, or changes to the main conclusions drawn from research that could potentially influence a reader’s health related behaviour. Design Retrospective quantitative content analysis. Setting Journal articles, press releases, and related news, with accompanying simulations. Sample Press releases (n=462) on biomedical and health related science issued by 20 leading UK universities in 2011, alongside their associated peer reviewed research papers and news stories (n=668). Main outcome measures Advice to readers to change behaviour, causal statements drawn from correlational research, and inference to humans from animal research that went beyond those in the associated peer reviewed papers. Results 40% (95% confidence interval 33% to 46%) of the press releases contained exaggerated advice, 33% (26% to 40%) contained exaggerated causal claims, and 36% (28% to 46%) contained exaggerated inference to humans from animal research. When press releases contained such exaggeration, 58% (95% confidence interval 48% to 68%), 81% (70% to 93%), and 86% (77% to 95%) of news stories, respectively, contained similar exaggeration, compared with exaggeration rates of 17% (10% to 24%), 18% (9% to 27%), and 10% (0% to 19%) in news when the press releases were not exaggerated. Odds ratios for each category of analysis were 6.5 (95% confidence interval 3.5 to 12), 20 (7.6 to 51), and 56 (15 to 211). At the same time, there was little evidence that exaggeration in press releases increased the uptake of news. Conclusions Exaggeration in news is strongly associated with exaggeration in press releases. Improving the accuracy of academic press releases could represent a key opportunity for reducing misleading health related news
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TUNGSTEN SHIELDS FOR CS-137 INLINE MONITORS IN THE CAUSTIC SIDE SOLVENT EXTRACTION PROCESS
The Department of Energy (DOE) selected Caustic-Side Solvent Extraction (CSSX) as the preferred technology for the removal of radioactive cesium from High-Level Waste (HLW) at the Savannah River Site (SRS). The CSSX process is a continuous process that uses a novel solvent to extract cesium from highly radioactive waste and concentrate it in dilute nitric acid. In-line analyses are performed with gamma-ray monitors to measure the C-137 concentration in the decontaminated salt solution (DSS) and in the strip effluent (SE). Sodium iodide (NaI) monitors are used to measure the Cs-137 concentration before the DSS Hold Tank, while Geiger-Mueller (GM) monitors are used for Cs-137 measurements before the SE hold tank. Tungsten shields were designed using Monte Carlo calculations and fabricated to provide the needed reduction of the process background radiation at the detector positions. A one-inch tungsten cylindrical shield reduced the background radiation by a factor of fifty that was adequate for the GM detectors, while a three-and-one-half-inch tungsten cylindrical shield was required for the NaI detectors. Testing of the NaI shield was performed at the SRS Instrument Calibration Facility. Based on this testing, the as-built shield is predicted to be able to detect the MCU DSS stream at concentrations above 0.003 Ci/gal under the ''worst case'' field conditions with a MCU feed solution of 1.1 Ci/gal and all of the process tanks completely full. This paper discusses the design, fabrication, testing and implementation of the tungsten shields in the MCU facility
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The hydrology of the humid tropics
Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change, including human-induced change. Human influences on population growth, land use and climate change will profoundly influence tropical hydrology, yet understanding of key hydrological interactions is limited. We propose that efforts to collect tropical data should explicitly emphasize characterizing moisture and energy fluxes from below the ground surface into the atmosphere. Research needs to chiefly involve field-based characterizations and modelling of moisture cycling and catchment processes, as well as long-term data acquisition and organization
Authors’ Reply to Letter to the Editor: Continued improvement to genetic diversity indicator for CBD
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The CoLaus study: a population-based study to investigate the epidemiology and genetic determinants of cardiovascular risk factors and metabolic syndrome
<p>Abstract</p> <p>Background</p> <p>Cardiovascular diseases and their associated risk factors remain the main cause of mortality in western societies. In order to assess the prevalence of cardiovascular risk factors (CVRFs) in the Caucasian population of Lausanne, Switzerland, we conducted a population-based study (Colaus Study). A secondary aim of the CoLaus study will be to determine new genetic determinants associated with CVRFs.</p> <p>Methods</p> <p>Single-center, cross-sectional study including a random sample of 6,188 extensively phenotyped Caucasian subjects (3,251 women and 2,937 men) aged 35 to 75 years living in Lausanne, and genotyped using the 500 K Affymetrix chip technology.</p> <p>Results</p> <p>Obesity (body mass index ≥ 30 kg/m<sup>2</sup>), smoking, hypertension (blood pressure ≥ 140/90 mmHg and/or treatment), dyslipidemia (high LDL-cholesterol and/or low HDL-cholesterol and/or high triglyceride levels) and diabetes (fasting plasma glucose ≥ 7 mmol/l and/or treatment) were present in 947 (15.7%), 1673 (27.0%), 2268 (36.7%), 2113 (34.2%) and 407 (6.6%) of the participants, respectively, and the prevalence was higher in men than in women. In both genders, the prevalence of obesity, hypertension and diabetes increased with age.</p> <p>Conclusion</p> <p>The prevalence of major CVRFs is high in the Lausanne population in particular in men. We anticipate that given its size, the depth of the phenotypic analysis and the availability of dense genome-wide genetic data, the CoLaus Study will be a unique resource to investigate not only the epidemiology of isolated, or aggregated CVRFs like the metabolic syndrome, but can also serve as a discovery set, as well as replication set, to identify novel genes associated with these conditions.</p
Changes of overweight and obesity in the adult Swiss population according to educational level, from 1992 to 2007
In many high income developed countries, obesity is inversely associated with educational level. In some countries, a widening gap of obesity between educational groups has been reported. The aim of this study was to assess trends in body mass index (BMI) and in prevalence of overweight and obesity and their association with educational level in the adult Swiss population.
Four cross-sectional National health interview surveys conducted in 1992/93 (n = 14,521), 1997 (n = 12,474), 2002 (n = 18,908) and 2007 (n = 17,879) using representative samples of the Swiss population (age range 18-102 years). BMI was derived from self-reported data. Overweight was defined as BMI > or = 25 and <30 kg/m(2), and obesity as BMI > or = 30 kg/m(2).
Mean (+/- standard deviation) BMI increased from 24.7 +/- 3.6 in 1992/3 to 25.4 +/- 3.6 kg/m2 in 2007 in men and 22.8 +/- 3.8 to 23.7 +/- 4.3 kg/m(2) in women. Between 1992/3 and 2007, the prevalence of overweight + obesity increased from 40.4% to 49.5% in men and from 22.3% to 31.3% in women, while the prevalence of obesity increased from 6.3% to 9.4% in men and from 4.9% to 8.5% in women. The rate of increase in the prevalence of obesity was greater between 1992/3 and 2002 (men: +0.26%/year; women: +0.31%/year) than between 2002 and 2007 (men: +0.10%/year; women: +0.10%/year). A sizable fraction (approximately 25%) of the increasing mean BMI was due to increasing age of the participants over time. The increase was larger in low than high education strata of the population. BMI was strongly associated with low educational level among women and this gradient remained fairly constant over time. A weaker similar gradient by educational level was apparent in men, but it tended to increase over time.
In Switzerland, overweight and obesity increased between 1992 and 2007 and was associated with low education status in both men and women. A trend towards a stabilization of mean BMI levels was noted in most age categories since 2002. The increase in the prevalence of obesity was larger in low education strata of the population. These findings suggest that obesity preventive measures should be targeted according to educational level in Switzerland
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