192 research outputs found
The Effects of Thermonuclear Reaction-Rate Variations on 26Al Production in Massive Stars: a Sensitivity Study
We investigate the effects of thermonuclear reaction rate variations on 26Al
production in massive stars. The dominant production sites in such events were
recently investigated by using stellar model calculations: explosive
neon-carbon burning, convective shell carbon burning, and convective core
hydrogen burning. Post-processing nucleosynthesis calculations are performed
for each of these sites by adopting temperature-density-time profiles from
recent stellar evolution models. For each profile, we individually multiplied
the rates of all relevant reactions by factors of 10, 2, 0.5 and 0.1, and
analyzed the resulting abundance changes of 26Al. Our simulations are based on
a next-generation nuclear physics library, called STARLIB, which contains a
recent evaluation of Monte Carlo reaction rates. Particular attention is paid
to quantifying the rate uncertainties of those reactions that most sensitively
influence 26Al production. For stellar modelers our results indicate to what
degree predictions of 26Al nucleosynthesis depend on currently uncertain
nuclear physics input, while for nuclear experimentalists our results represent
a guide for future measurements. We tabulate the results of our reaction rate
sensitivity study for each of the three distinct massive star sites referred to
above. It is found that several current reaction rate uncertainties influence
the production of 26Al. Particularly important reactions are 26Al(n,p)26Mg,
25Mg(alpha,n)28Si, 24Mg(n,gamma)25Mg and 23Na(alpha,p)26Mg. These reactions
should be prime targets for future measurements. Overall, we estimate that the
nuclear physics uncertainty of the 26Al yield predicted by the massive star
models explored here amounts to about a factor of 3.Comment: 44 pages, 16 figure
Campus Vol IV N 4
Lang, Pete. The Rain . Prose. 2.
Chase Jr., Richard and Jack K. Matthews Jr. Fitz and the Field house . Picture. 3.
Gould, Jim. After Graduation day . Prose. 4.
Runkle, Pete. As We Danced Off Both our Shoes . Prose. 5.
Hawk, Bob. Fields of Concentration For Seniors! . Cartoon. 6.
De Lackner, Barbara. Spring fever . Poem. 8.
Goodwin, Joyce. Would That Time Were A . Poem. 8.
Ward, Nancy. It Was Fall . Poem. 8.
Rounds, Dave. Untitled. Cartoon. 8.
Johnston, Ed. Campus Casuals . Prose. 9.
Gilbert, Ralph. Campus Progress Report . Picture. 10.
Rounds, Dave. Untitled. cartoon. 12
The Outcomes of Gestational Diabetes Mellitus after a Telecare Approach Are Not Inferior to Traditional Outpatient Clinic Visits
Objective. To evaluate the feasibility of a telemedicine system based on Internet and a short message service in pregnancy and its influence on delivery and neonatal outcomes of women with gestational diabetes mellitus (GDM). Methods. 100 women diagnosed of GDM were randomized into two parallel groups, a control group based on traditional face-to-face outpatient clinic visits and an intervention group, which was provided with a Telemedicine system for the transmission of capillary glucose data and short text messages with weekly professional feedback. 97 women completed the study (48/49, resp.). Main Outcomes Measured. The percentage of women achieving HbA1c values <5.8%, normal vaginal delivery and having a large for-gestational-age newborn were evaluated. Results. Despite a significant reduction in outpatient clinic visits in the experimental group, particularly in insulin-treated women (2.4 versus 4.6 hours per insulin-treated woman resp.; P < .001), no significant differences were found between the experimental and traditional groups regarding HbA1c levels (all women had HbA1c <5.8% during pregnancy), normal vaginal delivery (40.8% versus 54.2%, resp.; P > .05) and large-for-gestational-age newborns (6.1% versus 8.3%, resp.; P > .05). Conclusions. The system significantly reduces the need for outpatient clinic visits and achieves similar pregnancy, delivery, and newborn outcomes
Solar Neutrinos
Experimental work with solar neutrinos has illuminated the properties of
neutrinos and tested models of how the sun produces its energy. Three
experiments continue to take data, and at least seven are in various stages of
planning or construction. In this review, the current experimental status is
summarized, and future directions explored with a focus on the effects of a
non-zero theta-13 and the interesting possibility of directly testing the
luminosity constraint. Such a confrontation at the few-percent level would
provide a prediction of the solar irradiance tens of thousands of years in the
future for comparison with the present-day irradiance. A model-independent
analysis of existing low-energy data shows good agreement between the neutrino
and electromagnetic luminosities at the +/- 20 % level.Comment: 16 pages, 8 figures. Proceedings of International School on Nuclear
Physics; 27th Course: "Neutrinos in Cosmology, in Astro, Particle and Nuclear
Physics" in Erice, Sicily, Italy; September 16 - 24, 2005. To be published in
Progress Part. Nucl. Phy
Tratamiento de la hiponatremia secundaria al síndrome de secreción inadecuada de la hormona antidiurética: algoritmo multidisciplinar
Introducción: El síndrome de secreción inadecuada de la hormona antidiurética (SIADH) es la causa más frecuente de hiponatremia en el paciente hospitalizado. Sin embargo, faltan protocolos y algoritmos concretos que faciliten su abordaje terapéutico. Nuestro objetivo fue el desarrollo de dos algoritmos de tratamiento de la hiponatremia secundaria al SIADH en el paciente ingresado. Material y método: Un grupo multidisciplinar español compuesto por 2 especialistas en Endocrinología, 1 en Farmacia Hospitalaria, 2 en Medicina Interna y 2 en Nefrología se reunieron durante un año, bajo la tutela del grupo español del European Hyponatremia Network, y de las respectivas sociedades científicas españolas. Las pautas terapéuticas propuestas fueron basadas en recomendacio- nes ampliamente aceptadas, la práctica de expertos, guías de consenso, así como en la experiencia clínica de los autores. Resultados: Se elaboraron dos algoritmos de tratamiento. El Algoritmo 1 se dirige al tratamiento de la hiponatremia aguda como urgencia médica de abordaje inmediato, y es de aplicación al tratamiento de la hiponatremia grave tanto de tipo euvolémico como hipovolémico. Se basa en el uso de sueros salinos hipertónicos al 3 % i.v., con pautas de infusión y monitorización. Se expone cómo evitar la hipercorrección de la natremia y cómo corregirla en su caso. El Algoritmo 2 aborda el tratamiento de la hiponatremia no aguda leve o moderada asociada al SIADH. Expone cómo y cuándo usar la restricción hídrica, solutos, furosemida y tolvaptán, para alcanzar eunatremia en el paciente con SIADH. Conclusiones: Se han elaborado dos estrategias complementarias para el tratamiento de la hiponatremia inducida por SIADH, en un intento de fomentar la toma de conciencia acerca de esa patología, simplificar su abordaje y su tratamiento y, así, mejorar su pronóstico
Forest disturbance and regeneration: a mosaic of discrete gap dynamics and open matrix regimes?
Question: Recent research in boreal forest suggests that an ‘open matrix’ model may be more appropriate than the traditional model of spatially discrete gap dynamics for describing forest disturbance and regeneration, but what is the evidence from temperate broad-leaved deciduous forests concerning the prevalence of these alternative models?
Location: Semi-natural temperate broad-leaved deciduous forest in southern England.
Methods: Multi-temporal LiDAR data were used to monitor the changes in tree canopy height and canopy gaps over a 10-yr period for a 130-ha area of forest. Gap dynamics were characterized by quantifying gap creation, expansion, contraction and closure. By identifying the types and rates of canopy height transitions, areas of gap contraction and closure were attributed to the processes of lateral crown growth or vertical regeneration.
Results: Across the study site there was a zonation in canopy and gap properties and their dynamics. Many areas of the forest had the characteristics of open wood-pasture dominated by large, complex gaps being maintained under a regime of chronic disturbance. In these areas, several characteristics of the gap dynamics indicated that regeneration was restricted and this may be attributable to spatially-focused overgrazing by large herbivores. In contrast, other areas were characterized by high, closed canopy forest with small, discrete gaps where gap creation and infill were balanced.
Conclusions: At the landscape-scale broad-leaved deciduous forests contain a spatial mosaic of zones, which conform to different models of disturbance and regeneration dynamics; discrete gap dynamics and open matrix regimes are juxtaposed. It is now important to elucidate the abiotic factors and biotic interactions that determine the spatio-temporal distribution of the different regimes and to examine whether such a ‘regime mosaic’ model is applicable in other forest types
Effectiveness of Following Mediterranean Diet Recommendations in the Real World in the Incidence of Gestational Diabetes Mellitus (GDM) and Adverse Maternal-Foetal Outcomes: A Prospective, Universal, Interventional Study with a Single Group. The St Carlos Study
We reported that a Mediterranean Diet (MedDiet), supplemented with extra-virgin olive oil (EVOO) and pistachios, reduces GDM incidence and several other adverse outcomes. In order to assess its translational effects in the real world we evaluated the effect of MedDiet from 1st gestational visit in GDM rate compared with control (CG) and intervention (IG) groups from the previously referred trial. As secondary objective we also compared adverse perinatal outcomes between normoglycemic and diabetic women. This trial is a prospective, clinic-based, interventional study with a single group. 1066 eligible normoglycaemic women before 12 gestational weeks were assessed. 932 women (32.4 ± 5.2 years old, pre-gestational BMI 22.5 ± 3.5 kg/m2) received a motivational lifestyle interview with emphasis on daily consumption of EVOO and nuts, were followed-up and analysed. Binary regression analyses were used to examine the risk for each pregnancy outcome, pregnancy-induced hypertension, preeclampsia, gestational weight gain (GWG), caesarean-section, perineal trauma, preterm delivery, small (SGA) and large for gestational age (LGA), and Neonatal Intensive Care Unit admissions. GDM was diagnosed in 13.9%. This rate was significantly lower than the CG: RR 0.81 (0.73–0.93), p < 0.001 and no different from the IG: RR 0.96 (0.85–1.07), p = 0.468. GWG was lower in diabetic women (10.88 ± 6.46 vs. 12.30 ± 5.42 Kg; p = 0.013). Excessive weight gain (EWG) was also lower in GDM [RR 0.91 (0.86–0.96); p < 0.001] without a significant increase of insufficient weight gain. LGA were also lower (1 (0.8%) vs. 31 (3.9%); p < 0.05)), and SGA were similar (5 (3.8%) vs. 30 (3.7%)). LGA were associated to EWG (RR 1.61 (1.35–1.91), p < 0.001). Differences in other maternal-foetal outcomes were not found. In conclusions an early MedDiet nutritional intervention reduces GDM incidence and maternal-foetal adverse outcomes and should be universally applied as 1st line therapy. GDM might not be consider as a high risk pregnancy any longer
Family physician and endocrinologist coordination as the basis for diabetes care in clinical practice
<p>Abstract</p> <p>Background</p> <p>To estimate the proportion of diabetic patients (DPts) with peripheral vascular disease treated at a primary health care site after an endocrinologist-based intervention, who meet ATP III and Steno targets of metabolic control, as well as to compare the outcome with the results of the patients treated by endocrinologists.</p> <p>Methods</p> <p>A controlled, prospective over 30-months period study was conducted in area 7 of Madrid. One hundred twenty six eligible diabetic patients diagnosed as having peripheral vascular disease between January 2003 and June 2004 were included in the study. After a treatment period of three months by the Diabetes team at St Carlos Hospital, 63 patients were randomly assigned to continue their follow up by diabetes team (Group A) and other 63 to be treated by the family physicians (FP) at primary care level with continuous diabetes team coordination (Group B). 57 DPts from Group A and 59 from Group B, completed the 30 months follow-up period. At baseline both groups were similar in age, weight, time from diagnosis and metabolic control. The main outcomes of this study were the proportion of patients meeting ATP III and Steno goals for HbA1c (%), Cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, blood pressure, albumine-to-creatinine excretion ratio (ACR), body mass index (BMI), waist circumference (WC), anti-aggregation treatment and smoking status.</p> <p>Results</p> <p>At the end of the follow up, no differences were found between the groups. More than 37% of diabetic patients assigned to be treated by FP achieved a HbA1c < 6.5%, more than 50% a ACR < 30 mg/g, and more than 80% reached low risk values for cholesterol, LDL cholesterol, triglycerides, diastolic blood pressure and were anti-aggregated, and 12% remained smokers. In contrast, less than 45% achieved a systolic blood pressure < 130 mm Hg, less than 12% had a BMI < 25 Kg.m-2 (versus 23% in group A; p < 0.05) and 49%/30% (men/women) had a waist circumference of low risk.</p> <p>Conclusion</p> <p>Improvements in metabolic control among diabetic patients with peripheral vascular disease treated at a primary health care setting is possible, reaching similar results to the patients treated at a specialized level. Despite such an improvement, body weight control remains more than poor in both levels, mainly at primary care level. General practitioner and endocrinologist coordination care may be important to enhance diabetes management in primary care settings.</p> <p>Trial registration</p> <p>Clinical Trial number ISRCTN75037597</p
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