1,961 research outputs found
La Participación Ciudadana en la Obra Pública Municipal. Estudio de Caso: Los Comités Ciudadanos de Control y Vigilancia del Municipio de Toluca Estado de México, en el periodo 2009-2012
Se analizan y evaluan los aspectos de capacitación, operación, funcionamiento y grado de participación del ciudadano como contralor social, dentro de los Comités Ciudadanos de Control y Vigilancia (COCICOVI) en las obras públicas del municipio de Toluca, en el periodo 2009-2012
Aplicación del método de valoración contingente al parque natural de L'Albufera
El
trabajo que
aquÃ
se presenta
pretende,
por un lado, realizar un breve repaso de los
fundamentos
teóricos
del
método
de
valoración
contingente, sin olvidar los posibles sesgos
en los que se
puede
incurrir y, por
otro
lado, dada las ventajas que presenta dicho
método,
se
centrará
en la
aplicación
del mismo a un espacio de elevado
interés ecológico
como es el
Parque Natural de
L'Albufera
tratando
de
obtener
el valor de los servicios recreativos que
proporciona a los visitantes
(valor
de uso) asà como el valor de no uso
(existencia).
Por lo
tanto,
este
trabajo se encuadra
dentro
de lo que
McConnell (1985)
denomina
economÃa
de
las
actividades recreativas al aire libre
(Economics
of
outdoor
recreation
Stochastic angular momentum slews and flips and their effect on discs in galaxy formation models
The angular momentum of galactic discs in semi-analytic models of galaxy
formation is usually updated in time as material is accreted to the disc by
adopting a constant dimensionless spin parameter and little attention is paid
to the effects of accretion with misaligned angular momenta. These effects are
the subject of this paper, where we adopt a Monte-Carlo simulation for the
changes in the direction of the angular momentum of a galaxy disc as it
accretes matter based on accurate measurements from dark-matter haloes in the
Millennium II simulation. In our semi-analytic model implementation, the flips
seen the dark matter haloes are assumed to be the same for the cold baryons;
however, we also assume that in the latter the flip also entails a difficulty
for the disc to increase its angular momentum which causes the disc to become
smaller relative to a no-flip case. This makes star formation to occur faster,
specially in low mass galaxies at all redshifts allowing galaxies to reach
higher stellar masses faster. We adopt a new condition for the triggering of
starbursts during mergers. As these produce the largest flips it is natural to
adopt the disc instability criterion to evaluate the triggering of bursts in
mergers instead of one based on mass ratios as in the original model. The new
implementation reduces the average lifetimes of discs by a factor of 2, while
still allowing old ages for the present-day discs of large spiral galaxies. It
also provides a faster decline of star formation in massive galaxies and a
better fit to the bright end of the luminosity function at z = 0.Comment: 15 pages, 12 figures, MNRAS in pres
Gaussian covariance matrices for anisotropic galaxy clustering measurements
Measurements of the redshift-space galaxy clustering have been a prolific
source of cosmological information in recent years. Accurate covariance
estimates are an essential step for the validation of galaxy clustering models
of the redshift-space two-point statistics. Usually, only a limited set of
accurate N-body simulations is available. Thus, assessing the data covariance
is not possible or only leads to a noisy estimate. Further, relying on
simulated realisations of the survey data means that tests of the cosmology
dependence of the covariance are expensive. With these points in mind, this
work presents a simple theoretical model for the linear covariance of
anisotropic galaxy clustering observations with synthetic catalogues.
Considering the Legendre moments (`multipoles') of the two-point statistics and
projections into wide bins of the line-of-sight parameter (`clustering
wedges'), we describe the modelling of the covariance for these anisotropic
clustering measurements for galaxy samples with a trivial geometry in the case
of a Gaussian approximation of the clustering likelihood. As main result of
this paper, we give the explicit formulae for Fourier and configuration space
covariance matrices. To validate our model, we create synthetic HOD galaxy
catalogues by populating the haloes of an ensemble of large-volume N-body
simulations. Using linear and non-linear input power spectra, we find very good
agreement between the model predictions and the measurements on the synthetic
catalogues in the quasi-linear regime.Comment: 17 pages, 16 figures, 3 tables; modified to match version accepted by
MNRA
How complexity increases in development : An analysis of the spatial-temporal dynamics of Gene expression in Ciona intestinalis
The increase in complexity in an embryo over developmental time is perhaps one of the most intuitive processes of animal development. It is also intuitive that the embryo becomes progressively compartmentalized over time and space. In spite of this intuitiveness, there are no systematic attempts to quantify how this occurs. Here, we present a quantitative analysis of the compartmentalization and spatial complexity of Ciona intestinalis over developmental time by analyzing thousands of gene expression spatial patterns from the ANISEED database. We measure compartmentalization in two ways: as the relative volume of expression of genes and as the disparity in gene expression between body parts. We also use a measure of the curvature of each gene expression pattern in 3D space. These measures show a similar increase over time, with the most dramatic change occurring from the 112-cell stage to the early tailbud stage. Combined, these measures point to a global pattern of increase in complexity in the Ciona embryo. Finally, we cluster the different regions of the embryo depending on their gene expression similarity, within and between stages. Results from this clustering analysis, which partially correspond to known fate maps, provide a global quantitative overview about differentiation and compartmentalization between body parts at each developmental stage. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe
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