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Search Results: 1 - 10 of 144360 matches for " F.; Tafalla "
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Dust emission from young outflows: the case of L1157
F. Gueth,R. Bachiller,M. Tafalla
Physics , 2003, DOI: 10.1051/0004-6361:20030259
Abstract: We present new high-sensitivity 1.3 mm bolometer observations of the young outflow L1157. These data show that the continuum emission arises from four distinct components: a circumstellar disk, a protostellar envelope, an extended flattened envelope --the dense remnant of the molecular cloud in which the protostar was formed--, and the outflow itself, which represents ~20% of the total flux. The outflow emission exhibits two peaks that are coincident with the two strong shocks in the southern lobe of L1157. We show that the mm continuum is dominated by thermal dust emission arising in the high velocity material. The spectral index derived from the new 1.3 mm data and 850 mu observations from Shirley et al. (2000), is ~5 in the outflow, significantly higher than in the protostellar envelope (~3.5). This can be explained by an important line contamination of the 850 mu map, and/or by different dust characteristics in the two regions, possibly smaller grains in the post-shocks regions of the outflow. Our observations show that bipolar outflows can present compact emission peaks which must not be misinterpreted as protostellar condensations when mapping star forming regions.
El coste de la diabetes tipo 2 en Espa?a: El estudio CODE-2
Mata,M.; Anto?anzas,F.; Tafalla,M.; Sanz,P.;
Gaceta Sanitaria , 2002, DOI: 10.1590/S0213-91112002000600009
Abstract: objective: to estimate the cost of providing health care to patients with type 2 diabetes, by differentiating costs of the disease, costs of complications, and other unrelated health costs. methods: data on resource use were retrospectively collected from medical records and personal interviews in 29 primary health care centers in spain. patients were randomly selected from each center's diabetes registry. results: we evaluated 1004 patients (561 women) with a mean age of 67.42 years and a mean disease duration of 10.07 years. a total of 50.9% had no complications, 17.7% had macrovascular complications only, 19.5% had microvascular complications only and 11.9% presented both types of complication. the annual health cost per patient was 1305.15 euros. of this cost, 28.6% (373.27 euros) was directly related to diabetes control, 30.51% (398.20 euros) was related to complications of the disease, and 40.89% (533.68 euros) was unrelated. the mean cost of patients with no complications was 883 euros compared with 1403 euros for those with microvascular complications, 2022 euros for those with macrovascular complications and 2133 euros for patients with both types of complication. conclusions: because of the high cost of treating type 2 diabetes and its complications, preventive measures should be implemented and control of the disease should be improved to reduce the costs associated with chronic complications.
El coste de la diabetes tipo 2 en Espa a: El estudio CODE-2
Mata M.,Anto?anzas F.,Tafalla M.,Sanz P.
Gaceta Sanitaria , 2002,
Abstract: Objetivo: Estimar el coste de la atención sanitaria al paciente diabético tipo 2, diferenciando el gasto derivado del control de la enfermedad, de la atención de sus complicaciones y de otros costes directos asociados. Métodos: Recogida retrospectiva del consumo de recursos a partir de la historia clínica y la entrevista personal en 29 centros de atención primaria de todo el territorio nacional de una muestra de pacientes seleccionados de forma aleatoria a partir del registro de diabéticos de cada centro. Resultados: Se evaluó a 1.004 pacientes (561 mujeres) con una media de edad de 67,42 a os y una media de evolución de la enfermedad de 10,07 a os. El 50,9% no presentaba complicaciones, el 17,7% sólo macrovasculares, el 19,5% sólo microvasculares y el 11,9% ambas. El coste anual sanitario por paciente fue de 1.305,15 euros. De este coste el 28,6% (373,27 euros) estaba relacionado directamente con el control de la diabetes, el 30,51% (398,20 euros) con sus complicaciones y el 40,89% (533,68 euros) no estaba relacionado. El coste medio de un paciente sin complicaciones fue de 883 euros frente a 1.403 de un paciente con complicaciones microvasculares, 2.022 cuando existían complicaciones macrovasculares y 2.133 cuando coexistían ambos tipos de complicaciones. Conclusiones: El elevado coste del tratamiento de la diabetes tipo 2 y sus complicaciones, sugiere la posibilidad de que la mejora del control de la enfermedad pueda no sólo mejorar la supervivencia y la calidad de vida, sino reducir los costes asociados con las complicaciones crónicas.
The origin of the HH7-11 outflow
R. Bachiller,F. Gueth,S. Guilloteau,M. Tafalla,A. Dutrey
Physics , 2000,
Abstract: New, high-sensitivity interferometric CO J=2-1 observations of the HH 7-11 outflow show that despite previous doubts, this system is powered by the Class I source SVS 13. The molecular outflow from SVS 13 is formed by a shell with a large opening angle at the base, which is typical of outflows from Class I sources, but it also contains an extremely-high-velocity jet composed of ``molecular bullets'', which is more typical of Class 0 outflows. This suggests that SVS 13 could be a very young Class I, which still keeps some features of the previous evolutionary stage. We briefly discuss the nature of some sources in the SVS 13 vicinity which are emitters of cm-wave continuum, but have no counterpart at mm wavelengths.
Por una estética de la naturaleza: la belleza natural como argumento ecologista
Tafalla, Marta
Isegoría , 2005,
Abstract: In this paper, I defend the thesis that the aesthetics of nature can offer to the ethics of nature one of the best ecological arguments. I believe that !he aesthetic value of nature, which was traditionally neglected by philosophy, can revitalize the discussions which take place in the ethics of nature, and allows to approach in a new way the question if nature has an intrinsic or an instrumental value. En este artículo defiendo la tesis de que la estética de la naturaleza puede ofrecer a la ética de la naturaleza uno de los mejores argumentos ecologistas. Creo que el valor estético de la naturaleza, tradicionalmente olvidado por la filosofía, puede revitalizar las discusiones que tienen lugar en la ética de la naturaleza, y permite enfocar de un modo nuevo la cuestión de si la naturaleza posee un valor intrínseco o un valor instrumental.
The extremely collimated bipolar H_2O jet from the NGC 1333-IRAS 4B protostar
J. -F. Desmurs,C. Codella,J. Santiago-Garcia,M. Tafalla,R. Bachiller
Physics , 2009, DOI: 10.1051/0004-6361/200811365
Abstract: We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding medium. The main aim is to measure the absolute positions and proper motions of the H_2O spots in order to investigate the kinematics of the region from where the jet is launched. We imaged the protostars in the nearby region NGC 1333-IRAS 4 in the water maser line at 22.2 GHz by using the VLBA in phase-reference mode at the milliarcsecond scale over four epochs, spaced by one month to measure proper motions. Two protostars (A2 and B) were detected in a highly variable H_2O maser emission, with an active phase shorter than four weeks. The H_2O maps allow us to trace the fast jet driven by the B protostar: we observed both the red- and blue-shifted lobes very close to the protostar, =< 35 AU, moving away with projected velocities of ~10-50 km/s. The comparison with the molecular outflow observed at larger scale suggests a jet precession with a 18'/yr rate. By measuring the positional spread of the H_2O spots we estimate a jet width of ~2 AU at a distance of ~12 AU from the driving protostar.
Nota sobre la presencia romana en Guipúzcoa: Lucernas en Irún
Ma Teresa Amare Tafalla
Munibe Antropologia-Arkeologia , 1987,
Abstract: Se aportan datos al conocimiento del mundo romano en Guipúzcoa, más concretamente en Irún, extremo norte del conventus iuridicus caesaraugustanus, basándonos en el estudio de un material arqueológico muy concreto, las lucernas. Hemos analizado las procedentes de las explotaciones mineras de Arditurri y de las excavaciones efectuadas en la plaza de la iglesia de Santa María del Juncal de esta Villa. Son dieciséis piezas en total, fragmentos en su mayor parte, que nos hablan de una presencia romana o, al menos, de elementos de uso cotidiano asimilables a esta cultura durante el siglo I de la Era en ese territorio.
Dense core formation by fragmentation of velocity-coherent filaments in L1517
A. Hacar,M. Tafalla
Physics , 2011, DOI: 10.1051/0004-6361/201117039
Abstract: Context. Low-mass star-forming cores differ from their surrounding molecular cloud in turbulence, shape, and density structure. Aims. We aim to understand how dense cores form out of the less dense cloud material by studying the connection between these two regimes. Methods. We observed the L1517 dark cloud in C18O(1-0), N2H+(1-0), and SO(JN=32-21) with the FCRAO 14m telescope, and in the 1.2mm dust continuum with the IRAM 30m telescope. Results. Most of the gas in the cloud lies in four filaments that have typical lengths of 0.5 pc. Five starless cores are embedded in these filaments and have chemical compositions indicative of different evolutionary stages. The filaments have radial profiles of C18O(1-0) emission with a central flattened region and a power-law tail, and can be fitted approximately as isothermal, pressure-supported cylinders. The filaments, in addition, are extremely quiescent. They have subsonic internal motions and are coherent in velocity over their whole length. The large-scale motions in the filaments can be used to predict the velocity inside the cores, indicating that core formation has not decoupled the dense gas kinematically from its parental material. In two filaments, these large-scale motions consist of oscillations in the velocity centroid, and a simple kinematic model suggests that they may be related to core-forming flows. Conclusions. Core formation in L1517 seems to have occurred in two steps. First, the subsonic, velocity-coherent filaments have condensed out of the more turbulent ambient cloud. Then, the cores fragmented quasi-statically and inherited the kinematics of the filaments. Turbulence dissipation has therefore occurred mostly on scales on the order of 0.5 pc or larger, and seems to have played a small role in the formation of the individual cores.
Molecules in Bipolar Outflows
Mario Tafalla,Rafael Bachiller
Physics , 2012, DOI: 10.1017/S1743921311024896
Abstract: Bipolar outflows constitute some of the best laboratories to study shock chemistry in the interstellar medium. A number of molecular species have their abundance enhanced by several orders of magnitude in the outflow gas, likely as a combined result of dust mantle disruption and high temperature gas chemistry, and therefore become sensitive indicators of the physical changes taking place in the shock. Identifying these species and understanding their chemical behavior is therefore of high interest both to chemical studies and to our understanding of the star-formation process. Here we review some of the recent progress in the study of the molecular composition of bipolar outflows, with emphasis in the tracers most relevant for shock chemistry. As we discuss, there has been rapid progress both in characterizing the molecular composition of certain outflows as well as in modeling the chemical processes likely involved. However, a number of limitations still affect our understanding of outflow chemistry. These include a very limited statistical approach in the observations and a dependence of the models on plane-parallel shocks, which cannot reproduce the observed wing morphology of the lines. We finish our contribution by discussing the chemistry of the so-called extremely high velocity component, which seems different from the rest of the outflow and may originate in the wind from the very vicinity of the protostar.
Chains of dense cores in the Taurus L1495/B213 complex
M. Tafalla,A. Hacar
Physics , 2014, DOI: 10.1051/0004-6361/201424576
Abstract: (Abridged) We study the kinematics of the dense gas in the Taurus L1495/B213 filamentary region to investigate the mechanism of core formation. We use observations of N2H+(1-0) and C18O(2-1) carried out with the IRAM 30m telescope. We find that the dense cores in L1495/B213 are significantly clustered in linear chain-like groups about 0.5pc long. The internal motions in these chains are mostly subsonic and the velocity is continuous, indicating that turbulence dissipation in the cloud has occurred at the scale of the chains and not at the smaller scale of the individual cores. The chains also present an approximately constant abundance of N2H+ and radial intensity profiles that can be modeled with a density law that follows a softened power law. A simple analysis of the spacing between the cores using an isothermal cylinder model indicates that the cores have likely formed by gravitational fragmentation of velocity-coherent filaments. Combining our analysis of the cores with our previous study of the large-scale C18O emission from the cloud, we propose a two-step scenario of core formation in L1495/B213. In this scenario, named "fray and fragment," L1495/B213 originated from the supersonic collision of two flows. The collision produced a network of intertwined subsonic filaments or fibers ("fray" step). Some of these fibers accumulated enough mass to become gravitationally unstable and fragment into chains of closely-spaced cores. This scenario may also apply to other regions of star formation.
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