1,990 research outputs found
VLTI/AMBER spectro-interferometry of the late-type supergiants V766 Cen (=HR 5171 A), sigma Oph, BM Sco, and HD 206859
We add four warmer late-type supergiants to our previous
spectro-interferometric studies of red giants and supergiants.
V766 Cen (=HR 5171 A) is found to be a high-luminosity log(L/L_sun)=5.8+-0.4
source of Teff 4290+-760 K and radius 1490+-540 Rsun located close to both the
Hayashi and Eddington limits; this source is consistent with a 40 Msun
evolutionary track without rotation and current mass 27-36 Msun. It exhibits
NaI in emission arising from a shell of radius 1.5 Rphot and a photocenter
displacement of about 0.1 Rphot. V766 Cen shows strong extended molecular (CO)
layers and a dusty circumstellar background component. This suggest an
optically thick pseudo-photosphere at about 1.5 Rphot at the onset of the wind.
V766 Cen is a red supergiant located close to the Hayashi limit instead of a
yellow hypergiant already evolving back toward warmer Teff as previously
discussed.
The stars sigma Oph, BM Sco, and HD 206859 are found to have lower
luminosities of about log(L/Lsun)=3.4-3.5 and Teff of 3900-5300 K,
corresponding to 5-9 Msun tracks. They do not show extended molecular layers as
observed for higher luminosity red supergiants of our sample. BM Sco shows an
unusually strong contribution by an over-resolved circumstellar dust component.
These stars are more likely high-mass red giants instead of red supergiants.
This leaves us with an unsampled locus in the HR diagram corresponding to
luminosities log(L/Lsun)~3.8-4.8 or masses 10-13 Msun, possibly corresponding
to the mass region where stars explode as type II-P supernovae during the RSG
stage.
Our previously found relation of increasing strength of extended molecular
layers with increasing luminosities is now confirmed to extend to double our
previous luminosities and up to the Eddington limit. This might further point
to steadily increasing radiative winds with increasing luminosity.
[Abridged]Comment: 16 pages, 14 figures, accepted for publication in Astronomy and
Astrophysics (A&A
Tunable Low Density Palladium Nanowire Foams
Nanostructured palladium foams offer exciting potential for applications in
diverse fields such as catalyst, fuel cell, and particularly hydrogen storage
technologies. We have fabricated palladium nanowire foams using a cross-linking
and freeze-drying technique. These foams have a tunable density down to 0.1% of
the bulk, and a surface area to volume ratio of up to 1,540,000:1. They exhibit
highly attractive characteristics for hydrogen storage, in terms of loading
capacity, rate of absorption and heat of absorption. The hydrogen
absorption/desorption process is hysteretic in nature, accompanied by
substantial lattice expansion/contraction as the foam converts between Pd and
PdHx.Comment: 17 pages, 4 figure
Adaptive Control Optimization of Cutting Parameters for High Quality Machining Operations Based on Neural Networks and Search Algorithms
This book chapter presents an Adaptive Control with Optimization (ACO) system for optimising a multi-objective function based on material removal rate, quality loss function related to surface roughness, and cutting-tool life subjected to surface roughness specifications constraint
Monitorización con vÃdeo-EEG y ECG simultáneo para el diagnóstico diferencial de trastornos de conciencia transitorios. A propósito de un caso
We present the case of a 36 year-old woman, with history of transient
consciousness disorders with vegetative state, interpreted as epileptic crises
and treated with valproate for two years. After nine asymptomatic years, they
reappeared associated with migraine, vomiting and some generalized convulsions.
Electroencephalogram and cerebral magnetic resonance turned out normal, and
treatment with zonisamide was started, without beneficial results. Later
cardiological studies objectified a blockage of the left branch that coincided
with dizziness. The study was completed with Video-EGG monitoring, where there
was an episode that showed temporary right epileptiform activity, with a
diagnosis established of focal epilepsy of unknown cause. At present, she remains
asymptomatic with oxycarbazepine
Study of a Solution with COTS for the LHCb Calorimeter Upgrade
AbstractWe present a solution made out of Components Out of Shelf (COTS) for the analog processing of the signal of the LHCb calorimeters in the framework of the foreseen upgrade of the detector. The present proposal is based on the current functional solution, yet, to meet the stringent noise requirements, a number of modifications are proposed. Preliminary results on the prototype boards show promising results
Dietary Vitamin D Intake and Muscle Mass in Older Women. Results from a Cross-Sectional Analysis of the Epidos Study
Objectives: Vitamin D intake may prevent physical performance decline through prevention of muscle mass loss. Our objective was to determine whether low dietary intakes were associated with low muscle mass (MM). Design and participants: Cross-sectional analysis of 1989 community-dwelling women (mean age 80.5 +/- 3.8years) from the EPIDemiologie de l\u27OSteoporose (EPIDOS) study were assessed at baseline. Measurements: Low intakes of vitamin D (<70 mu g/week) were estimated from the weekly dietary vitamin D intakes (self-administered food frequency questionnaire). Low MM was defined according to the appendicular skeletal muscle mass index assessed using Dual Energy X-ray Absorptiometry, divided by square height of less than 5.45 kg/m(2). Usual gait speed defined physical performance. Age, sun exposure, co-morbidities, education level, living arrangements, recreational physical activity, dietary protein and calcium intakes, bone mineral density, handgrip strength, and body mass index were considered as potential confounders. Multivariate logistic regression analyses assessed the association between low vitamin D intakes and low MM. Results: Two-hundred and nine (10.5%) women with low MM were compared to 1,780 women with normal MM. In final model, obesity/overweight (Adjusted Odds Ratios, aOR=0.09; 95%CI [0.05-0.17]), malnutrition (aOR=3.90; 95%CI [2.74-5.54]) and low handgrip strength (aOR=2.33; 95%CI [1.44-3.77]; p<0.001) were statistically associated with a low MM status. Conclusion: No association with low MM has been reported regarding low dietary intakes of vitamin D
Integrated test environment for a part of the LHCb calorimeter - TWEPP09
An integrated test environment for the data acquisition electronics of the Scintillator Pad Detector (SPD) from the calorimeter of the LHCb experiment is presented. It allows to test separately every single board or to perform global system tests, while being able to emulate every part of the system and debug it. This environment is foreseen to test the production of spare electronic boards and help the maintenance of the SPD electronics along the life of the detector. The heart of the system is an Altera Stratix II FPGA while the main board can be controlled over USB, Ethernet or WiFi
Influencia de los métodos de conservación en las actividades enzimáticas de suelos forestales mediterráneos
Soil storage method may alter enzymatic activity being storage conditions of the soil samples prior to analysis decisive for the results. Studies made on freshly collected soils are generally preferred. However it is always not possible due to practical reasons since for example sampling is often restricted to short period of the year or because a great quantity of microbiological analyses must be made on time and by few people. On this context, soil storage methods are needed, being cold at 4°C the most widely used although sometimes alternative storage methods are also utilized. The aim of this study is to evaluate the effect of two alternative storage methods of soil samples (freezing at –20°C and air drying conservation methods) in comparison to cold at 4°C on the enzymatic activities (dehydrogenase, phosphatase, β-glucosidase and urease soil enzymes). Samples of two forest ecosystems (pine and holm oak forest stand) were taken in two different season of the year (winter and spring 2009). Results showed that enzymatic activities differed when freezing or air drying conservation methods were used in comparison with cold soil samples. Generally, alternative soil storage methods presented lower enzymatic activity than cold at 4°C. However, these changes depend on season and sampling location.El método de conservación del suelo utilizado puede alterar la actividad enzimática, siendo decisivas para los
resultados, las condiciones de conservación previas a los análisis. Para los estudios es preferible realizar los análisis
en muestras frescas y recién cogidas. Sin embargo, esto no es siempre posible por razones prácticas ya que las
muestras se tienen que recoger en un corto periodo del año o porque los análisis los debe hacer poca gente y siempre
en un determinado tiempo. En este contexto, se necesita un método de conservación, siendo el mantenimiento
en el frigorÃfico a 4°C el método más usado, aunque existen otros métodos alternativos. El objetivo de este trabajo
es el de evaluar el efecto de dos métodos alternativos de conservación (congelado a –20°C y secado a temperatura
ambiente) sobre las actividades enzimáticas (deshidrogenasa, fosfatasa, β-glucosidasa y ureasa), en comparación
con el mantenido en el frigorÃfico a 4°C. Las muestras se obtuvieron de dos zonas forestales diferentes (pinar
y encinar) y en dos épocas distintas (primavera y verano de 2009). Los resultados mostraron diferencias en las actividades
enzimáticas cuando se usó el congelado o secado al aire de las muestras de suelo en comparación con el
mantenimiento en el frigorÃfico. De forma general, los métodos de conservación alternativos mostraron una menor
actividad enzimática en las muestras de suelo analizadas. Sin embargo, estos cambios dependen de la época del año
y la zona de muestreo
Sarcopenia and cognitive impairment in elderly women: results from the EPIDOS cohort
BACKGROUND: common pathophysiological pathways are shared between age-related body composition changes and cognitive impairment.
OBJECTIVE: evaluate whether current operative sarcopenia definitions are associated with cognition in community-dwelling older women.
DESIGN: cross-sectional analyses.
SUBJECTS: a total of 3,025 women aged 75 years and older.
MEASUREMENTS: body composition (assessed by dual energy X-ray absorptiometry) and cognition (measured by short portable mental status questionnaire) were obtained in all participants. Multivariate logistic regression models assessed the association of six operative definitions of sarcopenia with cognitive impairment. Gait speed (GS, measured over a 6-meter track at usual pace) and handgrip strength (HG, measured by a hand-held dynamometer) were considered additional factors of interest.
RESULTS: a total of 492 (16.3%) women were cognitively impaired. The prevalence of sarcopenia ranged from 3.3 to 18.8%. No sarcopenia definition was associated with cognitive impairment after controlling for potential confounders. To proof consistency, the analyses were performed using GS and HG, two well-established predictors of cognitive impairment. Low GS [odds ratio (OR) 2.42, 95% confidence interval (CI) 1.72-3.40] and low HG (OR: 1.81, 95% CI: 1.33-2.46) were associated with cognitive impairment.
CONCLUSION: no significant association was evidenced between different operative sarcopenia definitions and cognitive impairment. The study suggests that the association between physical performance and cognitive impairment in not mediated by sarcopenia
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