77 research outputs found
From Giant H II regions and H II galaxies to globular clusters and compact dwarf ellipticals
Massive starforming regions like Giant HII Regions (GHIIR) and HII Galaxies
(HIIG) are emission line systems ionized by compact young massive star clusters
(YMC) with masses ranging from M to M. We model the
photometric and dynamical evolution over a Hubble time of the massive
gravitationally bound systems that populate the tight relation between absolute
blue magnitude and velocity dispersion () of GHIIR and HIIG and
compare the resulting relation with that one of old stellar systems: globular
clusters, elliptical galaxies, bulges of spirals. After 12~Gyr of evolution
their position on the vs. M plane coincides -- depending on the
initial mass -- either with the globular clusters for systems with initial mass
M or with a continuation of the ellipticals, bulges of
spirals and ultracompact dwarfs for YMC with M. The slope
change in the and -size relations at cluster masses around
M is due to the larger impact of the dynamical evolution on the
lower mass clusters. We interpret our result as an indication that the YMC that
ionize GHIIR and HIIG can evolve to form globular clusters and ultra compact
dwarf ellipticals in about 12 Gyr so that present day globular clusters and
ultra compact dwarf ellipticals may have formed in conditions similar to those
observed in today GHIIR and HIIG.Comment: 11 pages, 6 figures, accepted for publication in MNRA
An independent determination of the local Hubble constant
The relationship between the integrated H line luminosity and the
velocity dispersion of the ionized gas of HII galaxies and giant HII regions
represents an exciting standard candle that presently can be used up to
redshifts z ~ 4. Locally it is used to obtain precise measurements of the
Hubble constant by combining the slope of the relation obtained from nearby ( 0.2) HII galaxies with the zero point determined from giant HII regions
belonging to an `anchor sample' of galaxies for which accurate
redshift-independent distance moduli are available. We present new data for 36
giant HII regions in 13 galaxies of the anchor sample that includes the
megamaser galaxy NGC 4258. Our data is the result of the first four years of
observation of our primary sample of 130 giant HII regions in 73 galaxies with
Cepheid determined distances. Our best estimate of the Hubble parameter is
km /s Mpc This result is the product of
an independent approach and, although at present less precise than the latest
SNIa results, it is amenable to substantial improvement.Comment: 30 pages, 28 figures, Accepted to be published in MNRA
The L - \sigma\ relation for HII galaxies in green
The correlation between emission-line luminosity (L) and profile width
(sigma) for HII Galaxies provides a powerful method to measure the distances to
galaxies over a wide range of redshifts. In this paper we use SDSS
spectrophotometry to explore the systematics of the correlation using the
[OIII]5007 lines instead of Halpha or Hbeta to measure luminosities and line
widths. We also examine possible systematic effects involved in measuring the
profile-widths and the luminosities through different apertures. We find that
the green L-sigma relation defined using [OIII]5007 luminosities is
significantly more sensitive than Hbeta to the effects of age and the physical
conditions of the nebulae, which more than offsets the advantage of the higher
strength of the [OIII]5007 lines. We then explore the possibility of mixing
[OIII]5007 profile-widths with SDSS Hbeta luminosities using the Hubble
constant H0 to quantify the possible systematic effects. We find the mixed
L(Hbeta) sigma[OIII] relation to be at least as powerful as the canonical
L-sigma relation as a distance estimator, and we show that the evolutionary
corrections do not change the slope and the scatter of the correlation, and
therefore, do not bias the L-sigma distance indicator at high redshifts.
Locally, however, the luminosities of the Giant HII Regions that provide the
zero-point calibrators are sensitive to evolutionary corrections and may bias
the Hubble constant if their mean ages, as measured by the equivalent widths of
Hbeta, are significantly different from the mean age of the HII Galaxies. Using
a small sample of 16 ad-hoc zero point calibrators we obtain a value of H0 =
66.4\pm4.5 km s^-1 Mpc^-1 for the Hubble constant, which is fully consistent
with the best modern determinations, and that is not biased by evolutionary
corrections.Comment: 14 pages, 7 figures. Accepted for publication by A&
Potential for water and metal recovery from acid mine drainage by combining hybrid membrane processes with selective metal precipitation
Acid mining drainage has a serious impact on the environment. Forward osmosis allows the concentration of acid mine waters to favor the formation of enrichment sludges and subsequent selective metal precipitation. In this work, a methodology was proposed to treat mining effluents from the Iberian Pyrite Belt. Forward osmosis experiments were performed using different osmotic pressures from 0.5M to 2.5M NaCl to evaluate water fluxes and recovery. The water recovery obtained was in the range of 50-80%, and the flux remained above 5 (L•m−2•h−1). Four combined processes were modelled to determine the feasibility of eliminating water and precipitating metals. Furthermore, a new hybrid membrane process was proposed to recover at least 75% of water with recovery yields of Al, Fe, Cu, Zn and Mn of greater than 70%. A water production cost of 2.01 $/m3 and a specific energy consumption of 8.03 kWhe/m3 were estimated for the hybrid process
72- #1013 SOLUCIÓN DE UN PROBLEMA DE RUTEO MULTIDEPÓSITO CON FLOTA HETEROGÉNEA USANDO GENERACIÓN DE COLUMNAS
Este trabajo se enfoca en tres tipos de problemas diferentes relacionados con el diseño de las rutas de vehículos. El primero es aquél en el cual todos losvehículos son del mismo tipo (flota homogénea) y todaslas rutas salen y regresan al mismo depósito. Al agregarla posibilidad de usar distintos depósitos, se da másflexibilidad a la empresa, pero el problema también setorna más complejo ya que la cantidad de posibles rutasaumenta exponencialmente. Por último, se agrega laposibilidad de usar diferentes tipos de vehículos (flotaheterogénea) haciendo el problema aún más complejo. Debido a la complejidad del problema, los métodosestándar para solucionar problemas de optimizaciónson incapaces de proporcionar buenos resultados amedida que aumentan el número de clientes, dedepósitos y el tipo de vehículos. Debido a lo anterior, esnecesario utilizar otro método para obtener buenosresultados. El método que se propone en este trabajoes generación de columnas. Los métodos de generación de columnas inician conuna solución factible a partir de la cual se soluciona unProblema Maestro Restringido. Posteriormente se usanlas variables duales del problema anteriormentedescrito (descompuesto por Dantzig-Wolfe) parabuscar nuevas rutas que permitan mejorar el valor delmismo. Una vez encontradas dichas rutas, estas seincorporan al Problema Maestro Restringido y elproceso se repite. El algoritmo termina cuando noexisten más rutas que puedan mejorar el ProblemaMaestro Restringido. El factor clave en este método esque sólo requiere un subgrupo de variables en lugar detodas ellas Finalmente se aplica el método anteriormente descritoa un problema real de ruteo de una empresa deVending de la ciudad de Medellín y se analizan losresultados a partir de un problema con 48 clientes, trestipos de vehículos y dos depósito
Intervención familiar en diagnóstico reciente e inicio de tratamiento del cáncer infantil
La oncología pediátrica supone un campo de desarrollo profesional donde la figura del psicólogo desempeña importantes funciones. A lo largo del artículo se describen distintos aspectos psicosociales del abordaje sistémico del cáncer infantil. En primer lugar, se resumen los principales aspectos biológicos del cáncer y se ofrece una revisión de los presupuestos teóricos necesarios para el estudio y comprensión de estas realidades familiares donde se profundiza en el Modelo Psicosocial de Enfermedad (Rolland, 2000). Asimismo, se revisan los principales factores de riesgo y protección en las familias con un hijo con cáncer infantil y se exponen diferentes consideraciones con respecto a la comunicación del diagnóstico y la adaptación a la hospitalización. A partir de nuestra experiencia clínica en la planta de oncología pediátrica del Hospital “Virgen del Rocío” de Sevilla, en este trabajo se presenta un protocolo de actuación profesional que sistematiza la intervención psicológica orientada a ayudar a estas familias. En concreto, este protocolo describe la intervención psicológica llevada a cabo en el diagnóstico reciente y en el inicio del tratamiento del cáncer infantil, estructurando los diferentes objetivos a los que es necesario dar respuesta. Finalmente, se discuten diferentes consideraciones prácticas al hilo del protocolo descrito.Pediatric oncology is an area for professional development where the psychologist performs a crucial role. Different psycho-social aspects of the systemic approach to childhood cancer are described throughout this article. The first part summarizes the main biological aspects of cancer, followed by a review of the theoretical premises required for the study and understanding of these familiar realities, deepening on the Psychosocial Typology of Illness (Rolland, 2000). Furthermore, there is a review of the main risk and protection factors in families with one child with childhood cancer and also the exposition of different considerations related to the communication of the diagnosis and the adaptation to the hospitalization. In this article, a professional action protocol systematizing the psychological intervention intended to help this type of families is presented. This protocol is based on our personal clinical experience in the Paediatric Oncology Unit at Hospital “Virgen del Rocío” in Seville (Spain). Particularly, in this protocol the psychological intervention that take place during the diagnosis and at the beginning of the treatment of patients with childhood cancer is described, according to the proposed objectives. Finally, different practical considerations are discussed related to the described protocol
Estudio de la relación entre adherencia a la Escuela de la Espalda y afrontamiento del dolor en pacientes con lumbalgia crónica
Study of the relationship between adherence to back school and coping with pain in patients with chronic low back pain. Back School (BS) is a treatment modality for patients with chronic low back pain with educational contents associated with other therapeutic measures such as exercise. If followed, it is effective but it is well known that it is difficult to make changes to daily habits. This study evaluated whether patients completing BS had a predominance of active strategies in coping with pain, as they adhered better to the recommendations of BS. Material and method. Prospective observational study to evaluate BS adherence in patients with chronic low back pain. Adult patients attending BS were included in the study. Patients whose educational level, concomitant pathology or personal situation prevented them from completing the study were excluded. The patients were evaluated at the beginning and after the third session of BS. The variables studied were adherence to exercises and recommendations, coping with pain, pain intensity, functional disability and other sociodemographic characteristics. Results. A total of 67.2% of the 116 included patients acknowledged that they did not perform the exercises and recommendations of BS every day. No relationship was established between patients with active strategies for coping with pain and adherence to BS. Functional capacity and pain intensity did not differ between adherent and non-adherent patients. Conclusions. This study did not demonstrate that adherence to the exercises and habits taught in BS is related to coping with pain strategies, pain intensity and functional capacity in patients with chronic low back pain
The Caldera 60 years. No. 13
Gracias al compromiso social de Don Armando Puyana Puyana y del Dr. Alfonso Gómez Gómez, en 1952, se consolida la idea de fundar un colegio, no confesional, para acoger tanto a estudiantes como a maestros que, por razón de sus creencias políticas o religiosas, no tenían cabida en las instituciones oficiales de la época.Thanks to the social commitment of Don Armando Puyana Puyana and Dr. Alfonso Gómez Gómez, in 1952, the idea of founding a non-denominational school was consolidated to welcome both students and teachers who, due to their political or religious beliefs They had no place in the official institutions of the time
Evaluation of aminoglycoside and non-aminoglycoside compounds for stop-codon readthrough therapy in four lysosomal storage diseases
Nonsense mutations are quite prevalent in inherited diseases. Readthrough drugs could provide a therapeutic option for any disease caused by this type of mutation. Geneticin (G418) and gentamicin were among the first to be described. Novel compounds have been generated, but only a few have shown improved results. PTC124 is the only compound to have reached clinical trials. Here we first investigated the readthrough effects of gentamicin on fibroblasts from one patient with Sanfilippo B, one with Sanfilippo C, and one with Maro- teaux-Lamy. We found that ARSB activity (Maroteaux-Lamy case) resulted in an increase of 2 - 3 folds and that the amount of this enzyme within the lysosomes was also increased, after treatment. Since the other two cases (Sanfilippo B and Sanfilippo C) did not respond to gentamicin, the treatments were extended with the use of geneticin and five non-aminogly- coside (PTC124, RTC13, RTC14, BZ6 and BZ16) readthrough compounds (RTCs). No recovery was observed at the enzyme activity level. However, mRNA recovery was observed in both cases, nearly a two-fold increase for Sanfilippo B fibroblasts with G418 and around 1.5 fold increase for Sanfilippo C cells with RTC14 and PTC124. Afterwards, some of the products were assessed through in vitro analyses for seven mutations in genes responsible for those diseases and, also, for Niemann-Pick A/B. Using the coupled tran- scription/translation system (TNT), the best results were obtained for SMPD1 mutations with G418, reaching a 35% recovery at 0.25 μ g/ml, for the p.W168X mutation. The use of COS cells transfected with mutant cDNAs gave positive results for most of the mutations with some of the drugs, although to a different extent. The higher enzyme activity recovery, of around two-fold increase, was found for gentamicin on the ARSB p.W146X mutation. Our results are promising and consistent with those of other groups. Further studies of novelcompounds are necessary to find those with more consistent efficacy and fewer toxic effect
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