Emerging Universe from Scale Invariance

We consider a scale invariant model which includes a $R^{2}$ term in action and show that a stable "emerging universe" scenario is possible. The model belongs to the general class of theories, where an integration measure independent of the metric is introduced. To implement scale invariance (S.I.), a dilaton field is introduced. The integration of the equations of motion associated with the new measure gives rise to the spontaneous symmetry breaking (S.S.B) of S.I. After S.S.B. of S.I. in the model with the $R^{2}$ term (and first order formalism applied), it is found that a non trivial potential for the dilaton is generated. The dynamics of the scalar field becomes non linear and these non linearities are instrumental in the stability of some of the emerging universe solutions, which exists for a parameter range of the theory.Comment: 21 pages, 4 figures. Accepted for publication in JCA

Emergent universe in a Jordan-Brans-Dicke theory

In this paper we study emergent universe model in the context of a self interacting Jordan-Brans-Dicke theory. The model presents a stable past eternal static solution which eventually enters a phase where the stability of this solution is broken leading to an inflationary period. We also establish constraints for the different parameters appearing in our model.Comment: 18 pages, 4 figures. Accepted for publication in JCA

Una nueva hipótesis sobre la sucesión de los bosques tropicales húmedos y secos

In this paper 221 forest trees are grouped according to their habitat preferences into species preferring humid or dry and/or saline habitats or indifferent to the habitat type. Eleven functional traits classes (seeds per tree, seed size, seed weight, seeds per fruit, tolerance to shade, selectivity to habitat, sclerophylly, wood density, foliar area, tree height and tree volume) are arranged 1 to 4 according to a successional gradient. The strategies of forest trees are identified by analyzing the species matrices for humid forest ecosystems (joining species preferring humid habitats together with those indifferent to the habitat type) and for dry and/or saline ecosystems (joining species preferring dry and/or saline habitats and the ones indifferent to the habitat type). Both matrices are processed using the average taxonomic distance as the interval coefficient and by clustering analysis to discover successional organization patterns. The complexity of r-K continuum is discussed by focusing the K behavior of some variables among Pioneers (commonly r strategists) or the r behavior of some variables among Stabilizers (commonly K strategists). A new system of classification is presented as a hypothesis for discovering successional patterns in tropical forests.En el presente artículo agrupamos 221 especies forestales sobre la base de sus preferencias por tipos de hábitat húmedo o seco y/o salino, considerando aparte aquellas que son indiferentes al tipo de hábitat. El sistema de clasificación se sustentó en el empleo de clases de 11 variables funcionales (semillas por árbol, tamaño de las semillas, peso de las semillas, semillas por fruto, tolerancia a la sombra, selectividad al hábitat, esclerofilia, densidad de la madera, área foliar, altura del árbol y volumen del árbol) ordenadas de 1 a 4 de acuerdo con un gradiente sucesional. Las estrategias de las especies arbóreas se identificaron mediante el análisis de las matrices para ecosistemas forestales húmedos (uniendo las especies que prefieren hábitat húmedo con las que son indiferentes al tipo de hábitat) y para ecosistemas secos y/o salinos (uniendo las especies que prefieren hábitat seco y/o salino con las que son indiferentes al tipo de hábitat). Ambas matrices fueron procesadas mediante el uso del coeficiente de distancia taxonómica promedio y por análisis de clasificación para descubrir los patrones de organización sucesional. Se discutieron la complejidad del continuum r-K exponiendo el comportamiento K de algunas variables entre las Pioneras (que comúnmente son estrategas r) y el comportamiento r de algunas variables entre las Estabilizadoras (que comúnmente son estrategas K). Presentamos el nuevo sistema de clasificación como una hipótesis para descubrir los patrones sucesionales en bosques tropicales.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEInternational Foundation for Science (IFS) (Sweden)MacArthur Foundation and D. W. Reynolds Foundation (USA)David Rockefeller Center for Latin-American Studies (Cambridge, USA)The Ecological Society of America (ESA)( Washington, USA)pu

Using [C II] 158 μm Emission from Isolated ISM Phases as a Star Formation Rate Indicator

The brightest observed emission line in many star-forming galaxies is the [C II] 158 μm line, making it detectable up to z ~ 7. In order to better understand and quantify the [C II] emission as a tracer of star formation, the theoretical ratio between the [N II] 205 μm emission and the [C II] 158 μm emission has been employed to empirically determine the fraction of [C II] emission that originates from the ionized and neutral phases of the interstellar medium (ISM). Sub-kiloparsec measurements of the [C II] 158 μm and [N II] 205 μm lines in nearby galaxies have recently become available as part of the Key Insights in Nearby Galaxies: a Far Infrared Survey with Herschel (KINGFISH) and Beyond the Peak programs. With the information from these two far-infrared lines along with the multi-wavelength suite of KINGFISH data, a calibration of the [C II] emission line as a star formation rate (SFR) indicator and a better understanding of the [C II] deficit are pursued. [C II] emission is also compared to polycyclic aromatic hydrocarbon (PAH) emission in these regions to compare photoelectric heating from PAH molecules to cooling by [C II] in the neutral and ionized phases of the ISM. We find that the [C II] emission originating in the neutral phase of the ISM does not exhibit a deficit with respect to the infrared luminosity and is therefore preferred over the [C II] emission originating in the ionized phase of the ISM as an SFR indicator for the normal star-forming galaxies included in this sample

Best standards for data collection and reporting requirements on FOBs: towards a science-based FOB fishery management.

A major concern for tropical tunas, on these last years, has been the worldwide increasing use of drifting FOBs by purse seiners, which are equipped with satellite buoys and echo-sounders. The use of these floating objects has contributed to increase the catch of skipjack tuna, but also of juveniles of yellowfin and bigeye tunas. Moreover, it has increased the amount of by-catch (including some species classified as vulnerable or endangered) and has likely resulted in adverse effects on the ecology of fish and on vulnerable areas (e.g. beaching events on coral reef areas). Despite the increasing FOB use and concerns, little information is available on FOB use worldwide for an appropriate monitoring and management. Thus, FOB monitoring has become a priority in all tuna t-RFMOs. However, the data collection and reporting requirements around FOBs are not standardized and there are significant data gaps. The aim of this document is to review current requirements and procedures in place and propose standards for data collection and submission on FOBs to tRFMOs. The proposals included in this document are the result of a collaborative work between scientists and the fishing industry

Evaluation of a system to feedback information on Public Health: the experience of Area 2 of the Community of Madrid

BACKGROUND: In January 2000 the Public Health Service of Area 2, in the Region of Madrid, began to publish a weekly sheet on epidemiological and public health information (HISP) addressed to health professionals working in the Area. The aim of the present study was to estimate to how extend the "HISP" was known among health professionals of Area 2, and also to estimate the suitability and usefulness of its contents, during 2000. METHODS: A postal survey was carried out among a random sample of professionals working in Area 2. A descriptive analysis of main variables was done, variables associated to the knowledge of the "HISP" were investigated. Epi Info 2000 program was used for the analysis. RESULTS: The response rate was 79.7%. The best evaluated content was that related to epidemic outbreaks. An association between knowing the "HISP" and knowing the regional epidemiological bulletin (Boletin Epidemiológico de la Comunidad de Madrid) was found (OR = 9.3, IC 95% = 2.9-29.5), and also an association between knowing the "HISP" and being a physician (OR = 4.3, IC: 1.5-12.6, p = 0.005). CONCLUSIONS: The "HISP" has a good acceptance among health professionals of Area 2. They were more interested in contents related to stressful situations. It is necessary to improve the diffusion of information on public health among nursing professionals. Fundamento: En enero del año 2000 el Servicio de Salud Pública del Área Sanitaria 2 de la Comunidad de Madrid, inició la edición semanal de una Hoja de Información en Salud Pública (HISP) dirigida a los profesionales de la salud del Área. El presente trabajo tiene como objetivo estimar el conocimiento, aceptabilidad, utilidad y difusión de la HISP durante el año 2000. Métodos: Se realizó una encuesta por correo a una muestra de profesionales sanitarios del Área 2. Tras un análisis descriptivo se investigó, mediante análisis multivariante, qué factores explicaban que un profesional del Área conociera la HISP. Se utilizó el programa Epi Info 2000. Resultados: La tasa de respuesta fue del 79,7%. El apartado mejor valorado fue el de alertas en salud pública. Se encontró una asociación entre conocer la HISP y conocer el Boletín Epidemiológico de la Comunidad de Madrid (OR=9,3, IC 95%=2,9-29,5), y entre ser médico y recibir información de salud pública (OR=4,3, IC:1,5-12,6, p=0,005). Conclusiones: La HISP ha tenido buena aceptación entre los profesionales sanitarios del Área 2 que valoran más los contenidos relacionados con situaciones estresantes. Es necesario mejorar la difusión de la información de salud pública entre los profesionales de enfermería