3,480 research outputs found
Optical photometry of the UCM Lists I and II
We present Johnson B CCD photometry for the whole sample of galaxies of the
Universidad Complutense de Madrid (UCM) Survey Lists I and II. They constitute
a well-defined and complete sample of galaxies in the Local Universe with
active star formation. The data refer to 191 S0 to Irr galaxies at an averaged
redshift of 0.027, and complement the already published Gunn r, J and K
photometries. In this paper the observational and reduction features are
discussed in detail, and the new colour information is combined to search for
clues on the properties of the galaxies, mainly by comparing our sample with
other surveys.Comment: 14 pages, 7 PostScript figures, accepted for publication in A&AS,
also available vi ftp at ftp://cutrex.fis.ucm.es/pub/OUT/pag/PAPERS
Neural Connectivity with Hidden Gaussian Graphical State-Model
The noninvasive procedures for neural connectivity are under questioning.
Theoretical models sustain that the electromagnetic field registered at
external sensors is elicited by currents at neural space. Nevertheless, what we
observe at the sensor space is a superposition of projected fields, from the
whole gray-matter. This is the reason for a major pitfall of noninvasive
Electrophysiology methods: distorted reconstruction of neural activity and its
connectivity or leakage. It has been proven that current methods produce
incorrect connectomes. Somewhat related to the incorrect connectivity
modelling, they disregard either Systems Theory and Bayesian Information
Theory. We introduce a new formalism that attains for it, Hidden Gaussian
Graphical State-Model (HIGGS). A neural Gaussian Graphical Model (GGM) hidden
by the observation equation of Magneto-encephalographic (MEEG) signals. HIGGS
is equivalent to a frequency domain Linear State Space Model (LSSM) but with
sparse connectivity prior. The mathematical contribution here is the theory for
high-dimensional and frequency-domain HIGGS solvers. We demonstrate that HIGGS
can attenuate the leakage effect in the most critical case: the distortion EEG
signal due to head volume conduction heterogeneities. Its application in EEG is
illustrated with retrieved connectivity patterns from human Steady State Visual
Evoked Potentials (SSVEP). We provide for the first time confirmatory evidence
for noninvasive procedures of neural connectivity: concurrent EEG and
Electrocorticography (ECoG) recordings on monkey. Open source packages are
freely available online, to reproduce the results presented in this paper and
to analyze external MEEG databases
Entomological characterization of malaria in northern Colombia through vector and parasite species identification, and analyses of spatial distribution and infection rates
Background: Malaria remains a worldwide public health concern and, in Colombia, despite the efforts to stop malaria transmission, the incidence of cases has increased over the last few years. In this context, it is necessary to evaluate vector diversity, infection rates, and spatial distribution, to better understand disease transmission dynamics. This information may contribute to the planning and development of vector control strategies. Results: A total of 778 Anopheles mosquitoes were collected in fifteen localities of Córdoba from August 2015 to October 2016. Six species were identified and overall, Anopheles albimanus was the most widespread and abundant species (83%). Other species of the Nyssorhynchus subgenus were collected, including Anopheles triannulatus (13%), Anopheles nuneztovari (1%), Anopheles argyritarsis (< 1%) and two species belonging to the Anopheles subgenus: Anopheles pseudopunctipennis (3%) and Anopheles neomaculipalpus (< 1%). Four species were found naturally infected with two Plasmodium species: Anopheles nuneztovari was detected naturally infected with Plasmodium falciparum and Anopheles pseudopunctipennis with Plasmodium vivax, whereas An. albimanus and An. triannulatus were found infected with both parasite species and confirmed by nested PCR. Conclusions: In general, the obtained results were contrasting with previous studies in terms of the most abundant and widespread collected species, and regarding infection rates, which were higher than those previously reported. A positive relationship between mosquito local abundance at the locality level and human infection at the municipality level was found. Mosquito local abundance and the number of houses with mosquitoes in each village are factors explaining malaria human cases in these villages. The obtained results suggest that other factors related to the apparent variation in malaria eco-epidemiology in northern Colombia, must be identified, to provide health authorities with better decision tools aiming to design control and prevention strategies
Stellar populations in local star-forming galaxies. I.-Data and modelling procedure
We present an analysis of the integrated properties of the stellar
populations in the Universidad Complutense de Madrid Survey of Halpha-selected
galaxies. In this paper, the first of a series, we describe in detail the
techniques developed to model star-forming galaxies using a mixture of stellar
populations, and taking into account the observational uncertainties. We assume
a recent burst of star formation superimposed on a more evolved population. The
effects of the nebular continuum, line emission and dust attenuation are taken
into account. We also test different model assumptions including the choice of
specific evolutionary synthesis model, initial mass function, star formation
scenario and the treatment of dust extinction. Quantitative tests are applied
to determine how well these models fit our multi-wavelength observations for
the UCM sample. Our observations span the optical and near infrared, including
both photometric and spectroscopic data. Our results indicate that extinction
plays a key role in this kind of studies, revealing that low- and
high-extinction objects may require very different extinction laws and must be
treated differently. We also demonstrate that the UCM Survey galaxies are best
described by a short burst of star formation occurring within a quiescent
galaxy, rather than by continuous star formation. A detailed discussion on the
inferred parameters, such as the age, burst strength, metallicity, star
formation rate, extinction and total stellar mass for individual objects, is
presented in paper II of this series.Comment: 18 pages, 8 PostScript figures, minor changes to match the published
versio
Luminosity and Stellar Mass Functions of Local Star-Forming Galaxies
We present the optical and near-infrared luminosity and mass functions of the
local star-forming galaxies in the Universidad Complutense de Madrid Survey. A
bivariate method which explicitly deals with the Halpha selection of the survey
is used when estimating these functions. Total stellar masses have been
calculated on a galaxy-by-galaxy basis taking into account differences in star
formation histories. The main difference between the luminosity distributions
of the UCM sample and the luminosity functions of the local galaxy population
is a lower normalization (phi^*), indicating a lower global volume density of
UCM galaxies. The typical near-infrared luminosity (L^*) of local star-forming
galaxies is fainter than that of normal galaxies. This is a direct consequence
of the lower stellar masses of our objects. However, at optical wavelengths (B
and r) the luminosity enhancement arising from the young stars leads to M^*
values that are similar to those of normal galaxies. The fraction of the total
optical and near infrared luminosity density in the local Universe associated
with star-forming galaxies is 10-20%. Fitting the total stellar mass function
using a Schechter parametrization we obtain alpha=-1.15+/-0.15,
log({M}^*)=10.82+/-0.17 Msun and log(phi^*)=-3.04+/-0.20 Mpc^{-3}. This gives
an integrated total stellar mass density of 10^{7.83+/-0.07} Msun Mpc^{-3} in
local star-forming galaxies (H_0=70 km s^{-1} Mpc^{-1}, Omega_M=0.3,
Lambda=0.7). The volume-averaged burst strength of the UCM galaxies is
b=0.04+/-0.01, defined as the ratio of the mass density of stars formed in
recent bursts (age<10 Myr) to the total stellar mass density in UCM galaxies.
Finally, we derive that, in the local Universe, (13+/-3)% of the total baryon
mass density in the form of stars is associated with star-forming galaxies.Comment: 12 pages, 2 PostScript figures, published in ApJL. Minor changes to
match the published versio
Valoración del efecto de la calcitonina en la consolidación de la fractura de Colles
Se estudian cuarenta pacientes en que se ha producido una Fractura
de Epífisis Distal de Radio (Fractura de POUTEAU-COLLES) en pacientes
mayores de cincuenta años, con signos de osteoroporosis. Se han hecho
dos grupos aleatorios de veinte pacientes.
El grupo A se ha tratado con un programa de calcitonina y calcio que
cubre los tres primeros meses. El grupo B es tratado exclusivamente con
calcio, por igual período.
En ambos la reducción e inmovilización sigue los mismos criterios.
Se evalúan los resultados, observando que el grupo A presenta menos
secuelas dolorosas.The authors have studied 40 patients with fracture of distal
epiphysis of radius (POUTEAU-COLLES' fracture) all of them fifty
years old with signs of osteoporosis.
They have made two groups of patients (20 every one).
The group A has been treated with a program of calcitonin and
calcium during three months. The group B has been treated only
with calcium, three months, as well as the other group.
Both groups have the same criterion of reduction and inmovilization.
The evaluation of results in the first group showed less painful
consequences
- …