4,403 research outputs found

    A methodology for population projections: an application to Spain

    Get PDF
    This paper looks at projections for the Spanish population by sex and age for the period of 2005 to 2050. These were carried out using forecasts for birth and mortality rates, and migration. These rates are calculated using two main sources of information. First, a multivariate time series model was applied for the series of variables from the 1970 to 2001 period. Second a model was estimated for life expectancy and for a synthetic fertility index. Both sources of information were combined to obtain the forecasts for the rates. Immigration rates are predicted by assuming three possible scenarios based on the maximum proportion that immigrants will represent in the Spanish population. With these variables a structure of ages and sex for the Spanish population is estimated using a cohort component model

    A methodology for population projections: an application to Spain

    Get PDF
    This paper looks at projections for the Spanish population by sex and age for the period of 2005 to 2050. These were carried out using forecasts for birth and mortality rates, and migration. These rates are calculated using two main sources of information. First, a multivariate time series model was applied for the series of variables from the 1970 to 2001 period. Second a model was estimated for life expectancy and for a synthetic fertility index. Both sources of information were combined to obtain the forecasts for the rates. Immigration rates are predicted by assuming three possible scenarios based on the maximum proportion that immigrants will represent in the Spanish population. With these variables a structure of ages and sex for the Spanish population is estimated using a cohort component model.Population projections, Time series, Factorial model, Bootstrap

    Variability in Quasar Broad Absorption Line Outflows I. Trends in the Short-Term versus Long-Term Data

    Get PDF
    Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. The variability of BALs can help us understand the structure, evolution, and basic physical properties of the outflows. Here we report on our first results from an ongoing BAL monitoring campaign of a sample of 24 luminous quasars at redshifts 1.2<z<2.9, focusing on C IV 1549 BAL variability in two different time intervals: 4 to 9 months (short-term) and 3.8 to 7.7 years (long-term) in the quasar rest-frame. We find that 39% (7/18) of the quasars varied in the short-term, whereas 65% (15/23) varied in the long-term, with a larger typical change in strength in the long-term data. The variability occurs typically in only portions of the BAL troughs. The components at higher outflow velocities are more likely to vary than those at lower velocities, and weaker BALs are more likely to vary than stronger BALs. The fractional change in BAL strength correlates inversely with the strength of the BAL feature, but does not correlate with the outflow velocity. Both the short-term and long-term data indicate the same trends. The observed behavior is most readily understood as a result of the movement of clouds across the continuum source. If the crossing speeds do not exceed the local Keplerian velocity, then the observed short-term variations imply that the absorbers are <6 pc from the central quasar.Comment: 14 pages, 7 figures, accepted for publication in MNRA

    Digital models of stone samples for didactical purposes

    Get PDF
    This paper presents a v irtual methodology based on the generation of virtual models of stones in the context of the virtual laboratories for the acquisition and evaluation of competences in stones identification. The generation of the models is carried out using a procedure based on close-range photogrammetry that allows to obtain a scaled mesh models with radiometric information and low file weight. The proposed methodology has been designed ad-hoc following the economy, quality and reality criteria to ensure a good adequacy, guaranteeing an adequate adaptation to the teaching-learning process and the integration of the models into working packages, which can be easily integrated in earning management system (LMS) platforms. The generated 3D models have a high level of detail and enable the interaction to take measurements, make cross sections and use specific tools that allow the student to perform a thorough analysis and identification of the stone using free/open source software.- (undefined

    Direct high-precision mass spectrometry of superheavy elements with SHIPTRAP

    Get PDF
    Direct mass measurements in the region of the heaviest elements were performed with the Penning-trap mass spectrometer SHIPTRAP at GSI Darmstadt. Utilizing the phase-imaging ion-cyclotron-resonance massspectrometry technique, the atomic masses of 251No (Z = 102), 254Lr (Z = 103), and 257Rf (Z = 104) available at rates down to one detected ion per day were determined directly for the first time. The ground-state masses of 254No and 255,256Lr were improved by more than one order of magnitude. Relative statistical uncertainties as low as δm/m ≈ 10−9 were achieved. Mass resolving powers of 11 000 000 allowed resolving long-lived low-lying isomeric states from their respective ground states in 251,254No and 254,255Lr. This provided an unambiguous determination of the binding energies for odd-A and odd-odd nuclides previously determined only indirectly from decay spectroscopy.Federal Ministry of Education & Research (BMBF) 05P15HGFNA 05P19HGFNA 05P21HGFN1 05P15UMFNA 05P21UMFN1Max Planck SocietyFoundation CELLEXNetherlands Organization for Scientific Research (NWO) 680-91-103European Commission under Marie Sklodowska-Curie Action FP7 MSC COFUND scheme European Research Council (ERC) 819957Ministry of Science and Innovation, Spain (MICINN) Spanish Government FPA2015-67694-P PID2019-104093GB-I00/AE

    Simulador de comportamiento de enjambre con Quorum Sensing bacteriano

    Get PDF
    One of the most useful tools in the design of path-planning solutions is simulators. Thanks to them, it is possible to predict the performance of certain control strategies. In this paper, a simulator is presented that implements a swarm of automatons, which perform a wild motion in a user-selected environment. The robots will have the quality to avoid collisions with different obstacles that affect their mobility since they are equipped with proximity sensors. The interface of this simulator was designed entirely with the Qt Designer software. Successful configurations that replicate the performance of the real prototype are presented. &nbsp;Una de las herramientas más útiles en el diseño de soluciones de planificación de trayectorias son los simuladores. Gracias a ellos, es posible predecir el rendimiento de determinadas estrategias de control. En este trabajo se presenta un simulador que implementa un enjambre de autómatas que realizan un movimiento salvaje en un entorno seleccionado por el usuario. Los robots tendrán la cualidad de evitar colisiones con diferentes obstáculos que afecten a su movilidad ya que están equipados con sensores de proximidad. La interfaz de este simulador se ha diseñado íntegramente con el software Qt Designer. Se presentan configuraciones exitosas que replican el desempeño del prototipo real. &nbsp
    corecore