La frontera en la memoria cinematográfica española: mitos, utopías y quimeras

This article defines and analyses two models of frontier. There two concepts assimilate to the two meanings of frontier in English. The first one is related to the territorial advancement of a given people and imply social, political, economic and cultural interchanges. The second one is the spatial frontier, in which the psychological effects of facing the unknown constitute its leading feature. From this point of view, ‘frontier cinema’ is defined here as a unique filmic genre. This article examines the Spanish production of this particular genre and the way in which myths, utopias, chimeras accounting to political interests and ideological influences in different historical contexts have shaped it’s the plot

Molecular Cloud Turbulence And The Star Formation Efficiency: Enlarging the Scope

We summarize recent numerical results on the control of the star formation efficiency (SFE), addressing the effects of turbulence and the magnetic field strength. In closed-box numerical simulations, the effect of the turbulent Mach number \Ms depends on whether the turbulence is driven or decaying: In driven regimes, increasing \Ms decreases the SFE, while in decaying regimes the converse is true. The efficiencies in non-magnetic cases for realistic Mach numbers \Ms \sim 10 are somewhat too high compared to observed values. Including the magnetic field can bring the SFE down to levels consistent with observations, but the intensity of the magnetic field necessary to accomplish this depends again on whether the turbulence is driven or decaying. In this kind of simulations, a lifetime of the molecular cloud (MC) needs to be assumed. Further progress requires determining the true nature of the turbulence driving and the lifetimes of the clouds. Simulations of MC formation by large-scale compressions in the warm neutral medium (WNM) show that the clouds' initial turbulence is produced by the accumulation process that forms them, and that the turbulence is driven for as long as this process lasts, producing realistic velocity dispersions and also thermal pressures in excess of the mean WNM value. In simulations including self-gravity, but neglecting the magnetic field and stellar energy feedback, the clouds never reach an equilibrium state, but rather evolve secularly, increasing their mass and gravitational energy until they engage in generalized gravitational collapse. However, local collapse events begin midways through this process, and produce enough stellar objetcs to disperse the cloud or at least halt its collapse before the latter is completed.Comment: 8 pages, 2 postscript figures, invited talk in IAU Symposium 237, "Triggered Star Formation in a Turbulent ISM", 14-18 August, Prague, Czech Republic, eds. B. Elmegreen & J. Palous. Abstract abridge

Quiescent and coherent cores from gravoturbulent fragmentation

[abridged] We investigate the velocity structure of protostellar cores that result from non-magnetic numerical models of the gravoturbulent fragmentation of molecular cloud material. A large fraction of the cores analyzed are ``quiescent'', and more than half are identified as ``coherent''. The fact that dynamically evolving cores in highly supersonic turbulent flows can be quiescent may be understood because cores lie at the stagnation points of convergent turbulent flows, where compression is at a maximum, and relative velocity differences are at a minimum. The coherence may be due to an observational effect related to the length and concentration of the material contributing to the line. The velocity dispersion of the our cores often has its local maximum at small offsets from the column density maximum, suggesting that the core is the dense region behind a shock. Such a configuration is often found in observations of molecular cloud cores, and argues in favor of the gravoturbulent scenario of stellar birth as it is not expected in star-formation models based on magnetic mediation. Cores with collapsed objects tend to be near equipartition between their gravitational and kinetic energies, while cores without collapsed objects tend to be gravitationally unbound, suggesting that gravitational collapse occurs immediately after gravity becomes dominant. Finally, cores in simulations driven at large scales are more frequently quiescent and coherent, and have more realistic ratios of $M_{\rm vir}/M$, supporting the notion that molecular cloud turbulence is driven at large scales.Comment: ApJ, in pres

Contenido de los documentos informativos dirigidos a las mujeres sobre el cribado de cáncer de mama en España

OBJECTIVE: There are several methods to promote informed decision making before undergoing a screening program. This research aimed to analyze the contents of official documents about breast cancer screening programs. METHODS: A descriptive research was performed. After a literature review an agreed checklist was performed with the information needed to make decisions about participation in mammography screening programs. Informative documents about mammography screening valid in Spain in 2016 were analyzed by two independent researchers. The inter-rater agreement was verified and the discrepancies were solved by consensus. Absolute and relative frequencies of each item were calculated. RESULTS: 8 invitations and 14 citation letters, 12 leaflets, 8 brochures and 14 websites, from 18 screening programs, were reviewed. The information turned out to be very different according to each program. Only a third warned that participation is voluntary. 8 programs (44.4%) offered information on what is breast cancer and 7 (38.9%) on the cumulative risk of developing the disease. 15 (83.3%) explained the objectives of the program and 14 (77.8%) explained what mammography is. 14 programs (77.8%) presented as screening benefits the least invasive treatments, 12 the increase in survival (66.7%) and 10 the decrease in specific mortality (55.6%). Most of the programs did not report the possibility of false positives (27.8%) or false negatives (38.9%). Only 7 (38.9%) mentioned the possibility of overdiagnosis and 6 (33.3%) of overtreatment. CONCLUSIONS: The information provided by the different breast cancer screening programs is variable and does not contain sufficient information for informed decision-making.OBJETIVO: Existen diversos metodos para facilitar la toma de decisiones informada antes de acudir a un programa de cribado. El objetivo de este trabajo fue analizar la informacion de los documentos oficiales sobre los programas de cribado de cancer de mama (PCCM).METODOS: Estudio descriptivo. Analisis del contenido de los documentos informativos de los PCCM vigentes en Espana en 2016. Se elaboro una lista de comprobacion con la informacion necesaria para la toma de decisiones. Dos investigadores revisaron independientemente los documentos. Se comprobo la concordancia interinvestigador y se resolvieron por consenso las discrepancias. Se calcularon las frecuencias absolutas y relativas de cada item.RESULTADOS: Se revisaron 8 cartas de invitacion a participar y 14 de citacion, 12 dipticos o tripticos, 8 folletos y 14 webs, procedentes de 18 PCCM. La informacion resulto ser muy dispar segun cada programa. 8 programas (44,4%) informaban sobre que es el cancer de mama y 7 (38,9%) sobre el riesgo acumulado de desarrollarlo. 15 (83,3%) explicaban los objetivos del PCCM y 14 (77,8%) en que consiste una mamografia. 14 programas (77,8%) presentaban como beneficios el cribado los tratamientos menos invasivos, 12 el aumento de la supervivencia (66,7%) y 10 la disminucion de la mortalidad especifica (55,6%). La mayoria de los programas no informaban sobre la posibilidad de falsos positivos (27,8%) o falsos negativos (38,9%). Solo 7 (38,9%) mencionaban la posibilidad de sobrediagnostico y 6 (33,3%) de sobretratamiento.CONCLUSIONES: La informacion que facilitan los diferentes PCCM es variable y no contiene informacion suficiente para la toma de decisiones informada