3,226 research outputs found
Consumer populations and nutritional transition in Spain in the 20th century: A methodology for their reconstruction
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)
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
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
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
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
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 . Results are compared with phase-field numerical
simulations
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