2,088 research outputs found
Comparing Payments Between Sociobehavioral and Biomedical Studies in a Large Research University in Southern California
Given the dearth of regulatory guidance and empirical research on practices of providing payments to research participants, our study aimed to examine whether there were significant differences in payment amounts between sociobehavioral and biomedical studies and to examine study factors that may explain payment differences. This study reviewed 100 sociobehavioral and 31 biomedical protocols. Results showed that both biomedical studies and sociobehavioral studies had a wide variation of payments and, on average, the biomedical studies paid significantly more. Additionally, more biomedical studies offered payment than sociobehavioral studies. The primary factors that explained differences in payment amounts between sociobehavioral and biomedical studies were the number of study visits, study time, participation type, risk level, and research method. These findings provide pilot data to help inform future ethical decision-making and guidance regarding payment practices
Wind erosion control using crop residue II. Effects on millet establishment and yields
Effects of three levels of millet stover residue (0, 500, and 2000 kg ha−1) on establishment and growth of pearl millet (Pennisetum glaucum (L.) R.Br) were determined in a wind-erosion-affected area in Niger, West Africa, during 1991 and 1992. The extent of millet seedlings buried by blown soil in plots with 500 kg ha−1residues was similar to that of control plots. A residue amount of 2000 kg ha−1 reduced the extent of covered millet, but did not provide complete protection during severe sand storms. Partial covering of millet seedlings by blown soil decreased biomass yields compared to uncovered millet. Grain production, averaged over two years, was about 500 kg ha−1 for the control, 570 kg ha−1 with 500 kg ha−1residue, and 730 kg ha−1 with 2000 kg ha−1residue. Increased yields were caused by both winderosion protection and direct growth stimulating effects of residue. Stover yields for all treatments in both years were less than 2000 kg ha−1 and thus insufficient to sustain the levels required for protection of crops against winderosion damages. An increase in dry matter left in the field or the implementation of alternative winderosioncontrol measures is needed for sustainable crop production in wind-erosion-affected area
Wind erosion control using crop residue I. Effects on soil flux and soil properties
Effects of millet stover residue (0, 500, and 2000 kg ha−1) onwinderosionand surface soilproperties were determined from 1991 to 1993 at the ICRISAT Sahelian Center in Niger, West Africa. Soilflux 0.1 m above the ground was significantly reduced with 2000 kg ha−1residue but not with 500 kg ha−1. Topographic measurements indicated that soil removed from the soil surface was less with either residue level than in the control. After 2 y, the soil surface (0–0.01 m) of both residue treatments had less coarse sand than the control, but more fine sand and clay, more organic carbon and an increased cation exchange capacity. The organic-C content of blown material was greater than that of surface soil. An amount of 500 kg ha−1residue can be considered useful for soil conservation, but 2000 kg ha−1 are required for a significant reduction of soilflux caused during severe winderosion event
Wind erosion in the Southern Sahelian Zone and induced constraints to pearl millet production
On the sandy soils in the Southern Sahelian Zone, wind erosion owing to frequent short sand storms, especially at the beginning of the rainy season, is one of the constraints to crop growth. Sand storms and their effects on millet burial and growth were monitored during the 1990 growing season at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Sahelian Center, Niamey, Niger. During the growing season, the accumulated sand captured at 0.1 m above the soil surface attained 1262 kg m−2 vertical sampler opening. Ninety per cent of the millet pockets sown with the first rains were covered at 22 days after emergence and the crop was resown. During one single wind erosion event, 384 kg m−2 of sand was trapped and 40% of all millet pockets were totally covered. Surviving plants from the partially covered pockets showed delays in growth and development. The maximum plant height and leaf number were lower with a significant reduction in the leaf area index. Grain yield from unaffected pockets was nearly twice that of the pockets which were partially covered. Protection measures against wind erosion may have a potential to stabilize millet production in the Southern Sahelian Zone
Mesoscale simulations of surfactant dissolution and mesophase formation
The evolution of the contact zone between pure surfactant and solvent has
been studied by mesoscale simulation. It is found that mesophase formation
becomes diffusion controlled and follows the equilibrium phase diagram
adiabatically almost as soon as individual mesophases can be identified,
corresponding to times in real systems of order 10 microseconds.Comment: 4 pages, 2 figures, ReVTeX
Wind and Windblown Sand Damage to Pearl Millet
Pearl millet [Pennisetum glaucum (L.) R. Br.] is grown worldwide in areas affected by wind erosion, but no data on associated damage to millet are available. Laboratory wind tunnel experiments were conducted to determine the kind and extent of damage to millet caused by wind, sandblasting, and burial. In Exp. 1, millet was exposed for 15 min to wind (8, 11, or 14 m s−1) or wind + sand (8.3, 25.0, or 41.7 g m−1 s−1 sand abrader flux) at 8 and/or 16 d after emergence (DAE). Viable leaf area, leaf net photosynthesis, and NO3 content were measured through 21 DAE and dry matter production through 57 DAE. In Exp. 2, millet was seeded as three single seeds or in tufts, exposed to 25 g m−1 s−1 sand flux for 15 min at the 1-, 2-, or 3-leaf stage, and then manually covered by 15 mm sand. Survival was monitored weekly; dry matter was determined 70 DAE. In Exp. 1, survival was uniformly 100%. Wind alone or low sand flux had no effect on viable leaf area. High sand flux decreased viable leaf area by 74% at 2 d after the 8-DAE exposure and 42% at 5 d after the 16-DAE exposure. Photosynthesis of the remaining leaf area was reduced up to 88% immediately after exposure compared with the control, and NO3 content of sandblasted millet was increased up to six times. Dry weight was reduced 40% at 21 DAE by the highest sand flux, but 9.7% at 57 DAE. In Exp. 2, burial decreased millet survival and dry weight. Buried tufts had a higher survival rate and 35% more dry weight than buried single plants. Millet buried at the 1-leaf stage had 28% higher survival than plants treated later. Sandblasting reduced dry matter of buried millet only. Regression analyses between calculated total kinetic effects and growth parameters showed low r2 values. Millet can survive short-term sandblasting at any growth stage, but growth is reduced by strong sand flux, a sequence of wind erosion events during early growth, or by combinations of abrasion with burial by blown sand
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Harnessing the Medicaid Analytic eXtract (MAX) to Evaluate Medications in Pregnancy: Design Considerations
Background: In the absence of clinical trial data, large post-marketing observational studies are essential to evaluate the safety and effectiveness of medications during pregnancy. We identified a cohort of pregnancies ending in live birth within the 2000–2007 Medicaid Analytic eXtract (MAX). Herein, we provide a blueprint to guide investigators who wish to create similar cohorts from healthcare utilization data and we describe the limitations in detail. Methods: Among females ages 12–55, we identified pregnancies using delivery-related codes from healthcare utilization claims. We linked women with pregnancies to their offspring by state, Medicaid Case Number (family identifier) and delivery/birth dates. Then we removed inaccurate linkages and duplicate records and implemented cohort eligibility criteria (i.e., continuous and appropriate enrollment type, no private insurance, no restricted benefits) for claim information completeness. Results: From 13,460,273 deliveries and 22,408,810 child observations, 6,107,572 pregnancies ending in live birth were available after linkage, cleaning, and removal of duplicate records. The percentage of linked deliveries varied greatly by state, from 0 to 96%. The cohort size was reduced to 1,248,875 pregnancies after requiring maternal eligibility criteria throughout pregnancy and to 1,173,280 pregnancies after further applying infant eligibility criteria. Ninety-one percent of women were dispensed at least one medication during pregnancy. Conclusions: Mother-infant linkage is feasible and yields a large pregnancy cohort, although the size decreases with increasing eligibility requirements. MAX is a useful resource for studying medications in pregnancy and a spectrum of maternal and infant outcomes within the indigent population of women and their infants enrolled in Medicaid. It may also be used to study maternal characteristics, the impact of Medicaid policy, and healthcare utilization during pregnancy. However, careful attention to the limitations of these data is necessary to reduce biases
Hyperthyroidism from autoimmune thyroiditis in a man with type 1 diabetes mellitus: a case report
<p>Abstract</p> <p>Introduction</p> <p>The presentation, diagnosis, clinical course and treatment of a man with hyperthyroidism secondary to autoimmune thyroiditis in the setting of type 1 diabetes mellitus has not previously been described.</p> <p>Case presentation</p> <p>A 32-year-old European-American man with an eight-year history of type 1 diabetes mellitus presented with an unintentional 22-pound weight loss but an otherwise normal physical examination. Laboratory studies revealed a suppressed thyroid-stimulating hormone concentration and an elevated thyroxine level, which are consistent with hyperthyroidism. His anti-thyroid peroxidase antibodies were positive, and his thyroid-stimulating immunoglobulin test was negative. Uptake of radioactive iodine by scanning was 0.5% at 24 hours. The patient was diagnosed with autoimmune thyroiditis. Six weeks following his initial presentation he became clinically and biochemically hypothyroid and was treated with thyroxine.</p> <p>Conclusion</p> <p>This report demonstrates that autoimmune thyroiditis presenting as hyperthyroidism can occur in a man with type 1 diabetes mellitus. Autoimmune thyroiditis may be an isolated manifestation of autoimmunity or may be part of an autoimmune polyglandular syndrome. Among patients with type 1 diabetes mellitus who present with hyperthyroidism, Graves' disease and other forms of hyperthyroidism need to be excluded as autoimmune thyroiditis can progress quickly to hypothyroidism, requiring thyroid hormone replacement therapy.</p
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