4,567 research outputs found

    Star formation rates of distant luminous infrared galaxies derived from Halpha and IR luminosities

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    We present a study of the star formation rate (SFR) for a sample of 16 distant galaxies detected by ISOCAM at 15um in the CFRS0300+00 and CFRS1400+52 fields. Their high quality and intermediate resolution VLT/FORS spectra have allowed a proper correction of the Balmer emission lines from the underlying absorption. Extinction estimates using the Hbeta/Hgamma and the Halpha/Hbeta Balmer decrement are in excellent agreement, providing a robust measurement of the instantaneous SFR based on the extinction-corrected Halpha luminosity. Star formation has also been estimated exploiting the correlations between IR luminosity and those at MIR and radio wavelengths. Our study shows that the relationship between the two SFR estimates follow two distinct regimes: (1) for galaxies with SFRIR below ~ 100Msolar/yr, the SFR deduced from Halpha measurements is a good approximation of the global SFR and (2) for galaxies near of ULIRGs regime, corrected Halpha SFR understimated the SFR by a factor of 1.5 to 2. Our analyses suggest that heavily extincted regions completely hidden in optical bands (such as those found in Arp 220) contribute to less than 20% of the global budget of star formation history up to z=1.Comment: (1) GEPI, Obs. Meudon, France ;(2) CEA-Saclay, France ;(3) ESO, Gemany ;(4) IAC, Spain. To appear in A&

    Prevalence of sensorineural hearing loss in children and adolescents with diabetes mellitus

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    To establish the prevalence of sensorineural hearing loss (SNHL), as well as the predisposing risk factors, in children and adolescents with type 1 diabetes mellitus (T1DM) attending the Service of Endocrino-Pediatrics and Otolaryngology Department of the ‘‘Dr. José Eleuterio González’’ University Hospital and the Materno-Infantil Hospital, from January 2011 to December 2012. Material and methods: A total of 84 children with T1DM, with ages between 6 and 18 years old, were studied. Values of glycated hemoglobin (HbA1c) were assessed and Tonal audiometry and Speech audiometry tests were performed. Results: A total of 84 patients with a diagnosis of T1DM were studied, out of which 12 (14.3%) presented SNHL. Fifty percent of patients with hearing loss were in the age range of 10---13 years old. Regarding time of evolution with the disease (T1DM), 33% of patients with more than 5 years with T1DM presented SNHL, and nearly 88.9% of the patients with less than 5 years with T1DM presented normal hearing (p = 0.011). Moreover, 65.47% of the patients presented complications due to poor glycemic control at some point in the evolution of their disease. All (100%) diabetic patients with SNHL and 91% of the patients without SNHL had HbA1c values greater than 6%. In patients with hearing impairments, 83.3% suffered mild and 16.4% suffered moderate hearing loss. Most presented bilateral hearing loss, with the right ear dominating. Acute frequencies, mainly 8000 kHz, were the most affected

    Inverse Low Gain Avalanche Detectors (iLGADs) for precise tracking and timing applications

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    Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 mm2mm^2; and a good timing resolution, around 20-30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100%{\%} fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.Comment: Conference Proceedings of VCI2019, 15th Vienna Conference of Instrumentation, February 18-22, 2019, Vienna, Austri

    Modelling of bismuth segregation in InAsBi/InAs superlattices: Determination of the exchange energies

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    InAsBi dilute alloys are potential new candidates for the improvement of infrared optoelectronic devices such as photodetectors or lasers. In this work, InAsBi/InAs superlattices (SLs)with Bi contents ranging between 1 and 3% were grown by molecular beam epitaxy with different Bi fluxes and growth temperatures to analyze Bi segregation by cross sectional transmission electron microscopy techniques. Bi segregation profiles have been described layer-by-layer using a three-layer fluid exchange mechanism, extracting the values of the As/Bi exchange energies (E 1 , 1.26 ± 0.01 eV and E 2 , 1.36 ± 0.02 eV). A relationship to calculate the activation energies for exchange from the binding energies in III–V alloys is proposed, which would allow predicting them for other hitherto unknown compounds

    Proyecto de desarrollo de modelo de negocio Mercado Verde

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    Se plantea un modelo de negocio web/móvil que permita al segmento de mercado hombres y mujeres de 30 a 45 años de edad comprar y recibir productos naturales de manera conveniente. La idea es conseguir productores de calidad para una cantidad limitada de productos identificados como estratégicos, para partir de ahí como base y comenzar a ofrecerlos mediante medios digitales, para esto se generó una landing page página de aterrizaje (una página web diseñada específicamente para convertir visitantes en leads) que nos ayude a capturar clientes potenciales, así como información de ellos sobre los productos estratégicos. Toda esta propuesta se ha ido consolidando a través de más de 90 entrevistas presenciales con clientes potenciales, en donde semana a semana se hace una consolidación de la información en búsqueda de los hallazgos más relevantes, para a partir de ahí modificar si es necesario el modelo de negocio, pero también las entrevistas. También se ha medido la respuesta del mercado a través de la utilización de la landing page, con la cual se obtuvo una base de datos de 185 clientes potenciales con los cuales se está interactuando para consolidarlos como clientes reales y posteriormente como suscriptores.ITESO, A.C

    Fecundidad y desarrollo gonadal de la “boga” Leporinus obtusidens (Pisces, Anostomidae) en la represa Yacyretá, Argentina

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    En el presente trabajo se exponen los resultados obtenidos durante cinco años consecutivos de muestreos de boga Leporinus obtusidens en dos puntos del río Paraná, Argentina, considerando a uno de ellos como zona de impacto de la represa Yaciretá y otro sitio, lejano a la misma, como zona control. Se analiza la relación gonadosomática, las fecundidades absoluta y relativa y se describen las características morfológicas de los ovocitos en desarrollo. A pesar de las numerosas modificaciones que impone la presencia de una represa en las características de un río, los resultados sugieren que la boga no muestra repercusiones negativas en varios aspectos relacionados a la biología reproductiva en respuesta a las condiciones ambientales cambiantes y a niveles hídricos que fluctúan rápidamente
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