1,258 research outputs found
Leptonic secondary emission in a hadronic microquasar model
Context: It has been proposed that the origin of the very high-energy photons
emitted from high-mass X-ray binaries with jet-like features, so-called
microquasars (MQs), is related to hadronic interactions between relativistic
protons in the jet and cold protons of the stellar wind. Leptonic secondary
emission should be calculated in a complete hadronic model that include the
effects of pairs from charged pion decays inside the jets and the emission from
pairs generated by gamma-ray absorption in the photosphere of the system. Aims:
We aim at predicting the broadband spectrum from a general hadronic microquasar
model, taking into account the emission from secondaries created by charged
pion decay inside the jet. Methods: The particle energy distribution for
secondary leptons injected along the jets is consistently derived taking the
energy losses into account. We also compute the spectral energy distribution
resulting from these leptons is calculated after assuming different values of
the magnetic field inside the jets. The spectrum of the gamma-rays produced by
neutral pion-decay and processed by electromagnetic cascades under the stellar
photon field. Results: We show that the secondary emission can dominate the
spectral energy distribution at low energies (~1 MeV). At high energies, the
production spectrum can be significantly distorted by the effect of
electromagnetic cascades. These effects are phase-dependent, and some
variability modulated by the orbital period is predicted.Comment: 8 pages, 5 figures. Accepted for publication in Astronomy &
Astrophysic
Observations of microquasars with the MAGIC telescope
We report on the results from the observations in very high energy band (VHE,
E_gamma > 100GeV) of the black hole X-ray binary (BHXB) Cygnus X-1. The
observations were performed with the MAGIC telescope, for a total of 40 hours
during 26 nights, spanning the period between June and November 2006. We report
on the results of the searches for steady and variable gamma-ray signals,
including the first experimental evidence for an intense flare, of duration
between 1.5 and 24 hours.Comment: Contribution to the 30th ICRC, Merida Mexico, July 2007 on behalf of
the MAGIC Collaboratio
Tratamiento del síndrome de sufrimiento del mediano en el tunel carpiano
En 3 de los 8 casos se llevó a cabo la intervención quirúrgica: la carnicera, una costurera y el lechero acromegálico (en ambos dedos). Exponemos con detalle la técnica empleada. Los resultados fueron buenos, precoces y brillantes sobre las parestesias, más tardíos y moderados, pero evidentes, sobre las atrofias
La sorción de iodo como método de control de la modificación de la estructura de las fibras de poliéster.
A través de la sorción de iodo, se estudia la variación del volumen libre de las fibras de poliéster sometidas a tratamientos térmicos con calor seco o a tratamientos térmicos en presencia de agua y/o disolventes de uso frecuente en la industria textil o en los laboratorios de control. De la curva de sorción de iodo en función de la temperatura de termofijado, se deduce que la sorción a 65°C permite detectar diferencias estructurales ocasionadas por variaciones de la temperatura de termofijado de los artículos de lana poliéster y que la sensibilidad del procedimiento puede no ser suficiente para detectar el mismo tipo de diferencias en los artículos fibra celulósica-poliéster. Por otra parte, de la curva correspondiente se deduce que la sorción de iodo a 50°C puede utilizarse como método de control de las variaciones de la estructura y, consecuentemente, del comportamiento tintóreo que puede presentarse en la operación de texturación.
Se ha estudiado también el efecto producido en la estructura de la fibra por los tratamientos de tintura con y sin transportador, así como los ocasionados por disolventes como el percloroetileno, dioxano y cloruro de metileno. El percloroetileno actúa fijando la estructura de la fibra de modo similar a los transportadores utilizados. Por su parte, los tratamientos con dioxano y cloruro de metileno producen un aumento de la proporción de materia de bajo orden.La sorption d'iode permet d'étudier la variation du volume libre des fibres de polyester soumises a des traitements thermiques en chaleur sèche ou à des traitements thermiques en présence de l'eau et/ou de solvants d'usage fréquent dans l'industrie textile ou les laboratoires de controle. De la courbe de sorption d'indole en fonction de la température de thermofixage, on déduit que la sorption a 65°C permet de détecter des différences de structure provoquées par des variations de la température de thermofixage des articles laine/polyester; cependant, la sensibilité de la méthode n'est peut-être pas suffisante pour détecter ce même type de différences dans les articles fibres cellulosiques/polyester. D'autre part, il est possible d'utiliser la sorption d'iode à 50°C comme méthode de controle des variations de la structure et, par conséquent, du comportement tinctorial des articles ayant supporté l'operation de texturation.
Létude a en outre porté sur l'effet produit dans la structure de la fibre par les traitements de teinture avec et sans véhiculeur, ou par les traitements mettant en ouvre des solvants tels que le perchloréthylène, le dioxanne et le chlorure de méthylène. Le perchloréthylène, agit en fixant la structure de la fibre comme le font les véhiculeurs utilisés. D'autrepart, les traitements avec dioxanne et chlorure de méthylkne produisent un accroissement du taux de matiere à ordre cristalin faible.The iodine sorption allows to study the variation of the free volume of polyester fibres submitted to dry heat treatments or to hat treatments in the presence of water and/or solvents that are frequently used in the textile industry or control laboratories. From the iodine sorption curve as a function of the thermofixation temperature, it is inferred that the sorption at 65°C alloys to detect structure differences induced by variations of the thermofixation temperatures of the wool/polyester articles; nevertheless, the sensitivity of
the method is perhaps not sufficient to detect this same type of differences in the cellulosic-polyester articles. On the other hand, it is possible to use the iodine sorption at 500C as a control method of the variation of the structure and, consequently of the dyeing behaviour of articles having undergone
the texturizing operation.
Besides the study has related the produced effect in the fibre structure by dyeing treatments with and without carrier, or by treatments using solvents as perchlorethylene, dioxane, and methylene chloriae. The perchlorethylene sets the fibre structure as well as the carriers that were used. On the other hand, treatments with dioxane and methylene chloride product an increasing of rate of weak crystalline order.Peer Reviewe
Seasonal variation of inter-limb jumping asymmetries in youth team-sport athletes
The main objective of the present study was to provide seasonal variation data for inter-limb asymmetry in youth elite team-sport athletes. Fifty-nine players performed the single leg countermovement jump (SLCMJ) and the one leg hop for distance (OLHT) tests during pre-season, mid-season and end-season. A repeated-measures analysis of variance was conducted to determine magnitude differences in asymmetry scores between time points. Kappa coefficients (κ) were calculated to determine the levels of agreement for the direction of asymmetry. When comparing inter-limb asymmetry magnitudes across the season, the SLCMJ test showed significantly higher asymmetries at mid-season in comparison with pre-season and end-season (p<0.01, d=-1.03 for pre to mid; p<0.01, d=1.12 for pre to end). However, OLHT inter-limb asymmetry magnitude remained consistent throughout the season (ES range=-0.02 to -0.06). For the direction of asymmetry, levels of agreement ranged from poor to slight in the SLCMJ (k-0.10 to 0.18) and in the OLHT (k-0.21 to 0.18). No significant differences were found between mean asymmetry values at any time point or for either test when comparing males and females. In conclusion, jump height asymmetry during the SLCMJ was the only metric to show significant magnitude changes across the season
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