3,980 research outputs found
Analytical Modeling of Interference Aware Power Control for the Uplink of Heterogeneous Cellular Networks
Inter-cell interference is one of the main limiting factors in current
Heterogeneous Cellular Networks (HCNs). Uplink Fractional Power Control (FPC)
is a well known method that aims to cope with such limiting factor as well as
to save battery live. In order to do that, the path losses associated with
Mobile Terminal (MT) transmissions are partially compensated so that a lower
interference is leaked towards neighboring cells. Classical FPC techniques only
consider a set of parameters that depends on the own MT transmission, like
desired received power at the Base Station (BS) or the path loss between the MT
and its serving BS, among others. Contrary to classical FPC, in this paper we
use stochastic geometry to analyze a power control mechanism that keeps the
interference generated by each MT under a given threshold. We also consider a
maximum transmitted power and a partial compensation of the path loss.
Interestingly, our analysis reveals that such Interference Aware (IA) method
can reduce the average power consumption and increase the average spectral
efficiency. Additionally, the variance of the interference is reduced, thus
improving the performance of Adaptive Modulation and Coding (AMC) since the
interference can be better estimated at the MT.Comment: 13 pages, 1 table and 7 figures. This work has been submitted to the
IEEE for possible publication. Copyright may be transferred without notice,
after which this version may no longer be accessibl
ANÁLISIS DEL DESEMPLEO, LA MIGRACIÓN Y LA POBREZA EN MÉXICO
La mayoría de los movimientos poblacionales en todas las regiones geográficas del mundo, obedecen principalmente a motivaciones vinculadas con la búsqueda de mejores condiciones de vida. No obstante, en casi todos los casos el costo social de lograr que los hogares reciban lo necesario para sobrevivir es la ruptura familiar y la seguridad personal.Los graves problemas que están enfrentando las economías subdesarrolladas con bajo o nulo crecimiento económico, altas tasas de desempleo, elevado índice de migración y millones de
habitantes en pobreza extrema. El objetivo del presente trabajo fue analizar el desempleo, la migración y la pobreza en México. El desempleo es uno de los problemas de la economía mexicana (según INEGI de 5.5%), le sigue la migración y la pobreza extrema. Debido al incremento del desempleo y los bajos salarios que tiene el país estimulan a las personas a emigrar. Aunado a lo anterior, en Estados Unidos de América la tasa de desempleo de los migrantes mexicanos se elevó de 8.0% a 12.0% (2009) aproximadamente, provocando una fuerte disminución en las remesas, lo que trae como consecuencia una baja en los ingresos de las familias que viven de dichas transferencias ocasionando que se agudice la pobreza en el país
A Xenon Mass Gauging through Heat Transfer Modeling for Electric Propulsion Thrusters
The authors gratefully acknowledge the financial support given for this work by the Swedish National Space Board (NRFP-3 Call), COMSOL® advisors and OHB-Sweden for their interest on this topic.Peer reviewedPublisher PD
ANÃLISIS DEL DESEMPLEO, LA MIGRACIÓN Y LA POBREZA EN MÉXICO
Undeveloped economies are dealing with very big issues such as low or null economic growth, higher rates of unemployment, high index of migration and millions of people living in extreme poverty. Therefore, the present investigation aims to analyze unemployment, migration and poverty in Mexico; since unemployment in Mexico has a rate of 5.5% according to INEGI, followed by migration and extreme poverty. One of the most important effects from the previous matters is that they have stimulated people to migrate. Because of the unemployment increase and the low wages in the country it has been stimulated the population to migrate. In addition, in the USA, the unemployment rate of Mexican migrants has raised from 8.0 to 12.0% (2009) approximately, inducing a strong decrease in remittances, which brings as a consequence a diminish in families revenue that depend on such remittances, causing an intensification in the country's poverty.Unemployment, migration, poverty, remittances and income., Agribusiness,
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Angular clustering tomography and its cosmological implications
We investigate the cosmological implications of studying galaxy clustering
using a tomographic approach applied to the final BOSS DR12 galaxy sample,
including both auto- and cross-correlation functions between redshift shells.
We model the signal of the full shape of the angular correlation function,
, in redshift bins using state-of-the-art modelling of
non-linearities, bias and redshift-space distortions. We present results on the
redshift evolution of the linear bias of BOSS galaxies, which cannot be
obtained with traditional methods for galaxy-clustering analysis. We also
obtain constraints on cosmological parameters, combining this tomographic
analysis with measurements of the cosmic microwave background (CMB) and type Ia
supernova (SNIa). We explore a number of cosmological models, including the
standard CDM model and its most interesting extensions, such as
deviations from w_\rm{DE} = -1, non-minimal neutrino masses, spatial
curvature and deviations from general relativity using the growth-index
parametrisation. These results are, in general, comparable to the most
precise present-day constraints on cosmological parameters, and show very good
agreement with the standard model. In particular, combining CMB,
and SNIa, we find a value of w_\rm{DE} consistent with
to a precision better than 5\% when it is assumed to be constant in time, and
better than 6\% when we also allow for a spatially-curved Universe.Comment: 21 pages, 18 figures, accepted for publication MNRAS. The data used
in this analysis is publicly available at
https://sdss3.org/science/boss_publications.ph
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: single-probe measurements from CMASS anisotropic galaxy clustering
With the largest spectroscopic galaxy survey volume drawn from the SDSS-III
Baryon Oscillation Spectroscopic Survey (BOSS), we can extract cosmological
constraints from the measurements of redshift and geometric distortions at
quasi-linear scales (e.g. above 50 Mpc). We analyze the broad-range
shape of the monopole and quadrupole correlation functions of the BOSS Data
Release 12 (DR12) CMASS galaxy sample, at the effective redshift , to
obtain constraints on the Hubble expansion rate , the angular-diameter
distance , the normalized growth rate , and the
physical matter density . We obtain robust measurements by
including a polynomial as the model for the systematic errors, and find it
works very well against the systematic effects, e.g., ones induced by stars and
seeing. We provide accurate measurements ,
, , = , , , ,
where is the comoving sound horizon at the drag epoch and
Mpc is the sound scale of the fiducial cosmology used in
this study. The parameters which are not well constrained by our galaxy
clustering analysis are marginalized over with wide flat priors. Since no
priors from other data sets, e.g., cosmic microwave background (CMB), are
adopted and no dark energy models are assumed, our results from BOSS CMASS
galaxy clustering alone may be combined with other data sets, i.e., CMB, SNe,
lensing or other galaxy clustering data to constrain the parameters of a given
cosmological model. The uncertainty on the dark energy equation of state
parameter, , from CMB+CMASS is about 8 per cent. The uncertainty on the
curvature fraction, , is 0.3 per cent. We do not find deviation from
flat CDM.Comment: 15 pages, 11 figures. The latest version matches and the accepted
version by MNRAS. A bug in the first version has been identified and fixed in
the new version. We have redone the analysis with newest data (BOSS DR12
Petrographic and geochemical evidence for multiphase formation of carbonates in the Martian orthopyroxenite Allan Hills 84001
This research has been funded by the Spanish Ministry of Science and Innovation (projects: AYA2011‐26,522, AYA 2015‐67175‐P, CTQ2015‐62,635‐ERC, and CTQ2014‐60,119‐P to which J.M. Trigo‐Rodríguez and C.E. Moyano‐Cambero acknowledge financial support). The UK Science and Technology Facilities Council is also thanked for funding through grants ST/H002960/1, ST/K000942/1, and ST/L002167/1. ICN2 and ICMAB acknowledge support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program under Grants SEV‐2013‐0295 and SEV‐2015‐0496, respectively. We acknowledge B. Ballesteros and M. Rosado from the ICN2 Electron Microscopy Division, and A. Fernández from the ICTS (National Center of Electronic Microscopy) for the SEM, EDS, and microprobe measurements. We also thank the NASA Meteorite Working Group, and the Johnson Space Center for providing the ALH 84001,82 section. This study was done in the frame of a PhD on Physics at the Autonomous University of Barcelona (UAB) under the direction of J. M. Trigo‐Rodríguez.Peer reviewedPublisher PD
Effects of Maternal Fish Oil and/or 5-MethylTetrahydrofolate Supplementation during Pregnancy on Offspring Brain Resting-State at 10 Years Old: A Follow-Up Study from the NUHEAL Randomized Controlled Trial
Recent studies have shown that maternal supplementation with folate and long-chain
polyunsaturated fatty acids (LC-PUFAs) during pregnancy may affect children’s brain development.
We aimed at examining the potential long-term effect of maternal supplementation with fish oil
(FO) and/or 5-methyl-tetrahydrofolate (5-MTHF) on the brain functionality of offspring at the age
of 9.5–10 years. The current study was conducted as a follow-up of the Spanish participants
belonging to the Nutraceuticals for a Healthier Life (NUHEAL) project; 57 children were divided
into groups according to mother’s supplementation and assessed through functional magnetic
resonance imaging (fMRI) scanning and neurodevelopment testing. Independent component analysis
and double regression methods were implemented to investigate plausible associations. Children
born to mothers supplemented with FO (FO and FO + 5-MTHF groups, n = 33) showed weaker
functional connectivity in the default mode (DM) (angular gyrus), the sensorimotor (SM) (motor and
somatosensory cortices) and the fronto-parietal (FP) (angular gyrus) networks compared to the No-FO
group (placebo and 5-MTHF groups, n = 24) (PFWE < 0.05). Furthermore, no differences were found
regarding the neuropsychological tests, except for a trend of better results in an object recall (memory)
test. Considering the No-FO group, the aforementioned networks were associated negatively with
attention and speed-processing functions. Mother’s FO supplementation during pregnancy seems
to be able to shape resting-state network functioning in their children at school age and appears to
produce long-term effects on children´s cognitive processing.European Union (EU)
212652
007036Commission of the European Community within the 5th Framework Program
QLK1-CT-1999-00888European Research Council (ERC)
322605 META-GROWTHSpanish Ministry of Science, Innovation and Universities
FJCI-2017-3339
SDSS-III Baryon Oscillation Spectroscopic Survey data release 12 : galaxy target selection and large-scale structure catalogues
The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS) III project, has provided the largest survey of galaxy redshifts available to date, in terms of both the number of galaxy redshifts measured by a single survey, and the effective cosmological volume covered. Key to analysing the clustering of these data to provide cosmological measurements is understanding the detailed properties of this sample. Potential issues include variations in the target catalogue caused by changes either in the targeting algorithm or properties of the data used, the pattern of spectroscopic observations, the spatial distribution of targets for which redshifts were not obtained, and variations in the target sky density due to observational systematics. We document here the target selection algorithms used to create the galaxy samples that comprise BOSS. We also present the algorithms used to create large-scale structure catalogues for the final Data Release (DR12) samples and the associated random catalogues that quantify the survey mask. The algorithms are an evolution of those used by the BOSS team to construct catalogues from earlier data, and have been designed to accurately quantify the galaxy sample. The code used, designated mksample, is released with this paper.Publisher PDFPeer reviewe
Radio source calibration for the VSA and other CMB instruments at around 30 GHz
Accurate calibration of data is essential for the current generation of CMB
experiments. Using data from the Very Small Array (VSA), we describe procedures
which will lead to an accuracy of 1 percent or better for experiments such as
the VSA and CBI. Particular attention is paid to the stability of the receiver
systems, the quality of the site and frequent observations of reference
sources. At 30 GHz the careful correction for atmospheric emission and
absorption is shown to be essential for achieving 1 percent precision. The
sources for which a 1 percent relative flux density calibration was achieved
included Cas A, Cyg A, Tau A and NGC7027 and the planets Venus, Jupiter and
Saturn. A flux density, or brightness temperature in the case of the planets,
was derived at 33 GHz relative to Jupiter which was adopted as the fundamental
calibrator. A spectral index at ~30 GHz is given for each. Cas A,Tau A, NGC7027
and Venus were examined for variability. Cas A was found to be decreasing at
percent per year over the period March 2001 to August 2004.
In the same period Tau A was decreasing at percent per year. A
survey of the published data showed that the planetary nebula NGC7027 decreased
at percent per year over the period 1967 to 2003. Venus showed
an insignificant ( percent) variation with Venusian illumination.
The integrated polarization of Tau A at 33 GHz was found to be
percent at pa .}Comment: 13 pages, 15 figures, submitted to MNRA
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