3,167 research outputs found

    Consumer populations and nutritional transition in Spain in the 20th century: A methodology for their reconstruction

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    One feature of the modern nutrition transition is the growing consumption of animal proteins. The most common approach in the quantitative analysis of this change used to be the study of averages of food consumption. But this kind of analysis seems to be incomplete without the knowledge of the number of consumers. Data about consumers are not usually published in historical statistics. This article introduces a methodological approach for reconstructing consumer populations. This methodology is based on some assumptions about the diffusion process of foodstuffs and the modeling of consumption patterns with a log-normal distribution. This estimating process is illustrated with the specific case of milk consumption in Spain between 1925 and 1981. These results fit quite well with other data and indirect sources available showing that this dietary change was a slow and late process. The reconstruction of consumer population could shed a new light in the study of nutritional transitions.

    Health intervention and decline in infant mortality rates. Milk depots in Spain (1900-1936)

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    The role of public health has been a central topic on the classical debate about the historical mortality decline in Europe. One of these health initiatives were the Milk Depots. Spain set up those centres from the late 19th century until the beginning of the Civil War. The goal of this paper is to evaluate the effect of this health intervention on the infant mortality decline during this period. This study works out three kinds of sources: Statistical Yearbooks, Official documents and local records produced by the same Milk Depot. It analyses data available for all the country and one local case such as the Barcelona’s Milk Depot (1904-1935). The main methodological issue deals with the measurement of the effect of the Milk Depot activities on the pattern of changes of infant mortality. Results suggest that Milk Depots have a positive but quite moderate effect on the improving of overall levels of child survival.

    Rigorous coherent-structure theory for falling liquid films: Viscous dispersion effects on bound-state formation and self-organization

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    We examine the interaction of two-dimensional solitary pulses on falling liquid films. We make use of the second-order model derived by Ruyer-Quil and Manneville [Eur. Phys. J. B 6, 277 (1998); Eur. Phys. J. B 15, 357 (2000); Phys. Fluids 14, 170 (2002)] by combining the long-wave approximation with a weighted residuals technique. The model includes (second-order) viscous dispersion effects which originate from the streamwise momentum equation and tangential stress balance. These effects play a dispersive role that primarily influences the shape of the capillary ripples in front of the solitary pulses. We show that different physical parameters, such as surface tension and viscosity, play a crucial role in the interaction between solitary pulses giving rise eventually to the formation of bound states consisting of two or more pulses separated by well-defined distances and travelling at the same velocity. By developing a rigorous coherent-structure theory, we are able to theoretically predict the pulse-separation distances for which bound states are formed. Viscous dispersion affects the distances at which bound states are observed. We show that the theory is in very good agreement with computations of the second-order model. We also demonstrate that the presence of bound states allows the film free surface to reach a self-organized state that can be statistically described in terms of a gas of solitary waves separated by a typical mean distance and characterized by a typical density

    The soft X-ray background towards the northern sky. A detailed analysis of the Milky Way halo

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    We present a correlation analysis of the diffuse X-ray background emission of the ROSAT all-sky survey with the Leiden/Dwingeloo 21-cm HI line survey. We derive a consistent model for the diffuse X-ray background emission over about 50% of the sky. Only three diffuse X-ray components are necessary to fit the ROSAT data from 0.1 keV to 2.4 keV: a) the Local Hot Bubble, b) the Milky Way Halo, and c) the extragalactic X-ray background. Only one temperature of the hot coronal gas in the Milky Way Halo is needed. Our model predicts, that a major fraction of the 1/4 keV and about 50% of the 3/4 keV diffuse X-ray emission originates from the Milky Way Halo. We detect a difference between the intensities towards the Galactic center and its anti-center, which is consistent with the electron density distribution independently derived from pulsar dispersion measurements.Comment: Astron. Nachr. in press, issue dedicated to the proceedings of the workshop "X-ray Surveys in the light of New Observatories", Sep. 2002, Santander, Spai

    Avalanche dynamics in fluid imbibition near the depinning transition

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    We study avalanche dynamics and local activity of forced-flow imbibition fronts in disordered media. We focus on the front dynamics as the mean velocity vˉ\bar{v} of the interface is decreased and the pinning state is approached. Scaling arguments allow us to obtain the statistics of avalanche sizes and durations, which become power-law distributed due to the existence of a critical point at vˉ=0\bar{v}= 0. Results are compared with phase-field numerical simulations
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