3,844 research outputs found

    How do patients' clinical phenotype and the physiological mechanisms of the operations impact the choice of bariatric procedure?

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    Bariatric surgery is currently the most effective option for the treatment of morbid obesity and its associated comorbidities. Recent clinical and experimental findings have challenged the role of mechanical restriction and caloric malabsorption as the main mechanisms for weight loss and health benefits. Instead, other mechanisms including increased levels of satiety gut hormones, altered gut microbiota, changes in bile acid metabolism, and/or energy expenditure have been proposed as explanations for benefits of bariatric surgery. Beside the standard proximal Roux-en-Y gastric bypass and the biliopancreatic diversion with or without duodenal switch, where parts of the small intestine are excluded from contact with nutrients, resectional techniques like the sleeve gastrectomy (SG) have recently been added to the armory of bariatric surgeons. The variation of weight loss and glycemic control is vast between but also within different bariatric operations. We surveyed members of the Swiss Society for the Study of Morbid Obesity and Metabolic Disorders to assess the extent to which the phenotype of patients influences the choice of bariatric procedure. Swiss bariatric surgeons preferred Roux-en-Y gastric bypass and SG for patients with type 2 diabetes mellitus and patients with a body mass index >50 kg/m(2), which is consistent with the literature. An SG was preferred in patients with a high anesthetic risk or previous laparotomy. The surgeons' own experience was a major determinant as there is little evidence in the literature for this approach. Although trends will come and go, evidence-based medicine requires a rigorous examination of the proof to inform clinical practice

    Tracking the gradients using the Hessian: A new look at variance reducing stochastic methods

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    Our goal is to improve variance reducing stochastic methods through better control variates. We first propose a modification of SVRG which uses the Hessian to track gradients over time, rather than to recondition, increasing the correlation of the control variates and leading to faster theoretical convergence close to the optimum. We then propose accurate and computationally efficient approximations to the Hessian, both using a diagonal and a low-rank matrix. Finally, we demonstrate the effectiveness of our method on a wide range of problems.Comment: 17 pages, 2 figures, 1 tabl

    The junior South African individual scale as predictor of scholastic achievement at Sub A, Sub B & Std One levels

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    This study examines the relationship between the eight subtest form of the Junior South African Individual Scale (JSAIS - 8) and scholastic performance at Sub A, Sub B and Std One levels, as measured by teacher evaluations. An unreferred sample of 104 pupils who had been tested on the JSAIS- 8 in their Sub A year were followed up at the end of Std One. The pupils' three sets of year-end symbols, as recorded in the official school records, were obtained. Pearson correlations were calculated between the Global, Verbal Performance and Numerical Scales and each of the subtests on the one hand, and selected school subjects and a computed average of the subjects on the other. The JSAIS scales and subtests were regressed on the computed averages for each standard. A test was performed to evaluate the longitudinal stability of the correlation matrix of Pearson correlations. The results were compared with those of similar studies employing non-South African intelligence scales, and with a study employing the full, twelve subtest version of the JSAIS (JSAIS - 12). The values of the correlations yielded were found to be of the same general magnitude as those reported in studies employing non-South African scales. The test for the longitudinal stability of the Pearson correlation matrix indicated that the test probably predicted equally over the three standard levels. The Global, Verbal and Numerical Scales and their associated subtests correlated moderately to highly with measures of scholastic achievement. The Performance Scale and its subtests yielded lower and sometimes non-significant correlations. Some discrepancies were noted between the results of the present study and that which employed the JSAIS - 12. It was observed that three of the five subtests which yielded the highest correlations with scholastic achievement in the study employing the JSAIS - 12 are excluded from the JSAIS - 8. The possibility of substituting these subtests for three subtests currently incorporated in the JSAIS - 8 was explored. Limitations of the present study were discussed and the tentative nature of the findings emphasised. Suggestions were made for further research

    The Wide-field High-resolution Infrared TElescope (WHITE)

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    The Wide-field High-resolution Infrared TElescope (WHITE) will be dedicated in the first years of its life to carrying out a few (well focused in terms of science objectives and time) legacy surveys. WHITE would have an angular resolution of ~0.3'' homogeneous over ~0.7 sq. deg. in the wavelength range 1 - 5 um, which means that we will very efficiently use all the available observational time during night time and day time. Moreover, the deepest observations will be performed by summing up shorter individual frames. We will have a temporal information that can be used to study variable objects. The three key science objectives of WHITE are : 1) A complete survey of the Magellanic Clouds to make a complete census of young stellar objects in the clouds and in the bridge and to study their star formation history and the link with the Milky Way. The interaction of the two clouds with our Galaxy might the closest example of a minor merging event that could be the main driver of galaxy evolution in the last 5 Gyrs. 2) The building of the first sample of dusty supernovae at z<1.2 in the near infrared range (1-5 um) to constrain the equation of state from these obscured objects, study the formation of dust in galaxies and build the first high resolution sample of high redshift galaxies observed in their optical frame 3) A very wide weak lensing survey over that would allow to estimate the equation of state in a way that would favourably compete with space projects.Comment: Invited talk to the 2nd ARENA Conference : "The Astrophysical Science Cases at Dome C" Potsdam 17-21 September, 200

    Quantifying rainfall-runoff relationships on the Melkassa Hypo Calcic Regosol ecotope in Ethiopia

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    Droughts, resulting in low crop yields, are common in the semi-arid areas of Ethiopia and adversely influence the wellbeing of many people. The introduction of any strategy that could increase yields would therefore be advantageous. The objective of this study was to attempt to assess the influence of in-field rainwater harvesting (IRWH), compared to conventional tillage, on increasing the amount of water available to a crop like maize on a semi-arid ecotope at Melkassa situated in the eastern part of the Rift Valley. To achieve the objective of the study rainfall-runoff measurements were made during 2003 and 2004 on 2 m x 2 m plots provided with a runoff measuring system and replicated 3 times for each treatment. There were 2 treatments: conventional tillage (CT) on which hand cultivation was practised in a way that simulated the normal local CT; and a flat surface simulatingthe no-till, undisturbed surface of the IRWH technique (NT).Rainfall-runoff measurements were made over 2 rainy seasons during which there were 25 storms with > 9 mm of rain. From the 25 storms, only the 2nd season storms (8 storms) had runoff measurements. These storms were used for calibration and validation of the Morin and Cluff (1980) runoff model (MC Model). Appropriate values for final infiltration rate (If), surface storage (s) and for the crusting parameter (ĂŁ) were found to be: 6 mm.h-1; 1.0 mm for NT and 6.0 mm for CT;0.6 mm-1, respectively. The measured runoff (R) for the 2004 rainy season expressed as a fraction of the rainfall during the measuring period (P), i.e. R/P, gave values of 0.59 and 0.40 for the NT and CT treatments, respectively. There was a statistical differencebetween the runoff on the 2 treatments. Selected results from 7 years of field experiments with IRWH at Glen in South Africa were used together with measured maize yields and climate data over 16 seasons on the nearby Melkassa Experiment Station to estimate the yield benefits of IRWH compared to CT on the ecotope studied. The results ranged between 35 and 1 437 kg with a mean of 711 kg.ha-1 over the 16 years. At Melkassa this was an estimated yield increase ranging from 13% to 49%. The mean increase was 33%

    Quantifying rainfall-runoff relationships on the Mieso Hypo Calcic Vertisol ecotope in Ethiopia

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    Published ArticleDroughts are common in the semi-arid areas of Ethiopia and adversely influence the wellbeing of many of the 80% of the population involved in agriculture. The introduction of any strategy that could increase crop yields would therefore be advantageous. The objective of the study was to attempt to assess the benefit that the in-field rainwater harvesting (IRWH) crop production technique would have, compared to conventional tillage, on increasing soil water, and therefore the yield of a crop, on a semi-arid ecotope at Mieso. The mean annual rainfall at Mieso is 738 mm. The soil is a Hypo Calcic Vertisol with a high clay and silt content and is very susceptible to crusting. To achieve the objective of the study, rainfall-runoff measurements were made during 2003 and 2004 on 2 m x 2 m plots provided with a runoff measuring system, and replicated 3 times for each treatment. There were 2 treatments: conventional tillage (CT) that simulated the normal local CT; and a flat surface simulating the no-till IRWH technique (NT). Rainfall intensity was measured at 1-min intervals and runoff was measured after each storm. The Morin and Cluff runoff model was calibrated and validated using measured rainfall-runoff data. Appropriate values for final infiltration rate (If), surface storage (SD) and the crusting parameter (ĂŁ) were found to be: 10 mm.hr-1; 2 mm for NT and 5 mm for CT; 0.4 mm-1; respectively. The runoff (R)/rainfall (P) ratio (R/P) gave values of 0.43 and 0.34 for the NT and CT treatments, respectively. There was a statistical difference between the runoff on the 2 treatments. The first estimated yield benefit of IRWH compared to CT is 455 kg.ha-1. Based on the average long-term maize yield of 2 000 kg.ha-1 at Melkassa, this is an estimated yield increase of 23
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