A not so massive cluster hosting a very massive star

We present the first physical characterization of the young open cluster VVV CL041. We spectroscopically observed the cluster main-sequence stellar population and a very-massive star candidate: WR62-2. CMFGEN modeling to our near-infrared spectra indicates that WR62-2 is a very luminous (10$^{6.4\pm0.2} L_{\odot}$) and massive ($\sim80 M_{\odot}$) star.Comment: 1 page, 1 figure, to be published in the "International Workshop on Wolf-Rayet Stars conference proceedings" by Universit\"atsverlag Potsdam (editors: W.-R. Hamann, A. Sander, and H. Todt

neuroanatomical basis of behavioral disturbances in patients with prefrontal lesions

The role of the frontal lobe in control of behavioral and cognitive abilities is explored in a group of 34 patients with brain lesions restricted to the prefrontal cortex. The scores in both structured behavioral questionnaires and standard neuropsychological tests were analyzed using the injured area of the frontal lobe as the independent variable. Our results show that patients with simultaneous lesions in supero– and inferomedial areas of the prefrontal cortex exhibit higher behavioral disturbances. Bilateral lesions also are associated with greater behavioral troubles. On the contrary, cognitive abilities are globally impaired in prefrontal patients. Results are discussed in relation to current models of the organization of the prefrontal cortex and its role on behavior control

Free volume holes diffusion to describe physical aging in poly(mehtyl methacrylate)/silica nanocomposites

9 páginas, 5 figuras, 3 tablas.-- Trabajo presentado al "MACRO2010: 43rd IUPAC World Polymer Congress" celebrado en Glasgow (U.K.) del 11 al 16 de julio de 2010.The spontaneous thermodynamically driven densification, the so-called physical aging, of glassy poly(mehtyl methacrylate) (PMMA) and its nanocomposites with silica has been described by means of the free volume holes diffusion model. This mechanism is able to account for the partial decoupling between physical aging and segmental dynamics of PMMA in nancomposites. The former has been found to be accelerated in PMMA/silica nanocomposites in comparison to “bulk” PMMA, whereas no difference between the segmental dynamics of bulk PMMA and that of the same polymer in nanocomposites has been observed. Thus, the rate of physical aging also depends on the amount of interface polymer/nanoparticles, where free volume holes disappear after diffusing through the polymer matrix. The free volume holes diffusion model is able to nicely capture the phenomenology of the physical aging process with a structure dependent diffusion coefficient.The authors acknowledge the University of the Basque Country and Basque Country Government (Ref. No. IT- 436-07, Depto. Educación, Universidades e Investigación) and Spanish Minister of Education (Grant Nos. MAT 2007- 63681 and CSD2006-00053) for their support. The support of the Basque Government within the Etortek program is also acknowledged.Peer reviewe

Temporalidad, eficiencia técnica y productividad: El sector hotelero en Canarias

This research focuses on analyzing the effect of high employment temporality on technical efficiency and productivity. Previous literature points out a set of benefits and drawbacks related to fixed-term contracts. To ascertain the influence of temporality on efficiency, the critical case of the hotel sector in the Canary Islands is studied where the temporary employment rate (40%). So this paper explores the effect of temporary employment on technical efficiency in the hotel sector of the Canary Islands (a Spanish region). The magnitude of this case study can be clearly checked, given that the Canary Islands is the most popular region in the European Union visited by residents. A production stochastic frontier is estimated by distinguishing between two types of employment: permanent and temporary. Results suggest that high levels of temporality tend to reduce technical efficiency and productivity. A high conversion rate from temporary to permanent jobs seems to increase efficiency. The contribution of this paper is threefold: (i) filling the gap in the literature on the influence of temporary employment on technical efficiency, evaluating its effect for a case study where job temporality is dramatically high, (ii) partial factor productivities for permanent and fixed-term workers are estimated, and (iii) exploring the influence of less studied variables like the level of conversion from fixed-term to permanent employment on efficiency. The findings can be relevant for human resources management for firms where temporary rates are high. Human resource management should consider the type of labor contracts used, as well as the perspectives of conversion into permanent ones for their temporary workers, given their potential influence in technical efficiency, labour productivity, and firm performance.Esta investigación se centra en analizar el efecto de la alta temporalidad del empleo sobre la eficiencia técnica y la productividad. La literatura previa señala un conjunto de beneficios e inconvenientes relacionados con los contratos temporales. Para conocer la influencia de la temporalidad sobre la eficiencia, se estudia el caso crítico del sector hotelero en Canarias donde la tasa de temporalidad es del 40%. Así, este trabajo explora el efecto de la temporalidad sobre la eficiencia técnica en el sector hotelero de Canarias (región española). La magnitud de este caso de estudio puede comprobarse claramente, dado que las Islas Canarias es la región de la Unión Europea más visitada por los residentes. Se estima una frontera estocástica de producción distinguiendo entre dos tipos de empleo: permanente y temporal. Los resultados sugieren que altos niveles de temporalidad tienden a reducir la eficiencia técnica y la productividad. Una alta tasa de conversión de empleos temporales a permanentes parece aumentar la eficiencia. La contribución de este trabajo es triple: (i) llenar el vacío en la literatura sobre la influencia del empleo temporal en la eficiencia técnica, evaluando su efecto para un caso de estudio en el que la temporalidad del empleo es dramáticamente alta, (ii) se estiman las productividades parciales de los factores para los trabajadores permanentes y de duración determinada, y (iii) se explora la influencia de variables menos estudiadas como el nivel de conversión de empleo de duración determinada a permanente en la eficiencia. Las conclusiones pueden ser relevantes para la gestión de los recursos humanos de las empresas en las que las tasas de temporalidad son elevadas. La gestión de recursos humanos debería considerar el tipo de contratos laborales utilizados, así como las perspectivas de conversión en indefinidos de sus trabajadores temporales, dada su potencial influencia en la eficiencia técnica, la productividad laboral y el rendimiento de la empresa

El concepto de justicia en la Encíclica "Mater et magistra"

La idea de la Justicia ocupa un puesto central en la doctrina de la Encíclica Mater et Magistra del Papa Juan XXIII. La palabra "justicia" recurre en el texto de la Encíclica no menos de cuarenta veces. Esto no puede extrañar. La Justicia es una norma universal que regulta todas las relaciones sociales y económicas de los hombres. Este es un presupuesto fundamental de la doctrina social de los Papas desde León XIII hastas Pío XII. Es también la base de la enseñanza social de Juan XXIII en la Mater et Magistra

The embedded clusters DBS 77, 78, 102, and 160-161 and their link with the interstellar medium

Aims. We report a study of the global properties of some embedded clusters placed in the fourth quadrant of the Milky Way to clarify some issues related with their location into the Galaxy and their stellar formation processes. Methods. We performed BVI photometric observations in the region of DBS 77, 78, 102, 160, and 161 clusters and infrared spectroscopy in DBS 77 region. They were complemented with JHK data from VVV survey combined with 2MASS catalogue, and used mid-infrared information from GLIMPSE catalogue. We also searched for HI data from SGPS and PMN radio surveys, and previous spectroscopic stellar classification. The spectroscopic and photometric information allowed us to estimate the spectral classification of the brightest stars of each studied region. On the other hand, we used the radio data to investigate the interstellar material parameters and the continuum sources probably associated with the respective stellar components. Results. We estimated the basic physical parameters of the clusters (reddening, distance, age, and initial mass function). We searched for HII regions located near to the studied clusters and we analyzed the possible link between them. In the particular case of DBS 160-161 clusters, we identified the HI bubble B332.5-0.1-42 located around them. We found that the mechanical energy injected to the interstellar medium by the more massive stars of this couple of clusters was enough to generate the bubble.Comment: 15 pages, 14 figures, 6 tables, accepted for publication in A&

Spatio-temporal vulnerability assessment in fractured groundwater systems

Governance reforms are required to demonstrate adaptive and resilient urban water resource management that considers complexity, uncertainty in immediate and long term change. Contamination of groundwater is a complex process and full of uncertainty at local and regional scale. The main objective of this research is the study of vulnerability to pollution in an unconfined karstic aquifer. Mainly it is addressed vulnerability integration, in relation to policy, specifically in risk evaluation and risk–benefit considerations. Development of an integrated vulnerability assessment methodology can be useful to effectively manage and protect this valuable freshwater source. The research insights suggest that the establishment of a pattern of effective governance is mandatory as the future highway, the prison and the airport are overlaying the most vulnerable areas of the aquifer and therefore provide policy makers guidance in overcoming urban water governance challenges.info:eu-repo/semantics/publishedVersio