2,215 research outputs found
Exercise increases the dynamics of diurnal cortisol secretion and executive functionin people wiht MCI
Summary:
Regular physical activity is protective against and beneficial for Mild Cognitive Impairment (MCI), dementia, and Alzheimer´s disease. The mechanisms underlying these benefits remain unknown although it has been suggested that exercise-induced changes in the circadian pattern of cortisol secretion may be implicated. Fitness, salivary cortisol levels (0 and 30 mins post awakening, midday, 5pm and 9pm) and cognitive function were determined in a group of amnestic MCI patients (n=39) before and after a three-month exercise program (n=19) or usual care (n=20). At base fitness measures were positively correlated with peak levels of cortisol and a greater fall in cortisol concentration from peak levels to midday. The exercise intervention successfully increased fitness and resulted in a greater fall in cortisol concentration from peak to midday, compared to the control group. The exercise intervention enhanced indices of executive function, although memory, mood, and functionality were not affected
Fuzzy-based forest fire prevention and detection by wireless sensor networks
Forest fires may cause considerable damages both in ecosystems and lives.
This proposal describes the application of Internet of Things and wireless
sensor networks jointly with multi-hop routing through a real time and dynamic
monitoring system for forest fire prevention. It is based on gathering and
analyzing information related to meteorological conditions, concentrations of
polluting gases and oxygen level around particular interesting forest areas.
Unusual measurements of these environmental variables may help to prevent
wildfire incidents and make their detection more efficient. A forest fire risk
controller based on fuzzy logic has been implemented in order to activate
environmental risk alerts through a Web service and a mobile application. For
this purpose, security mechanisms have been proposed for ensuring integrity and
confidentiality in the transmission of measured environmental information.
Lamport's signature and a block cipher algorithm are used to achieve this
objective
Synthesis and luminescence properties of electrodeposited ZnO Films
ZnO films have been grown on gold (111) by electrodeposition using two
different OH- sources, nitrate and peroxide, in order to obtain a comparative
study between these films. The morphology, structural and optical
characterization of the films were investigated depending on the solution used
(nitrate and peroxide) and the applied potential. Scanning Electron Microscopy
pictures show different morphologies in each case. X-Ray Diffraction confirms
that the films are pure ZnO oriented along the (0002) direction. ZnO films have
been studied by photoluminescence to identify the emission of defects in the
visible range. A consistent model that explains the emissions for the different
electrodeposited ZnO films is proposed. We have associated the green and yellow
emissions to a transition from the donor OH- to the acceptor zinc vacancies
(VZn-) and to interstitial oxygen (Oi0), respectively. The orange-red emission
is probably due to transitions from the conducting band to Oi- and OZn 0
defects and the infrared emission to transition from these Oi -/2- and OZn 0/-
defects to the valence band.Comment: 17 pages, 1 Table and 10 figure
The nuclear and extended mid-infrared emission of Seyfert galaxies
We present subarcsecond resolution mid-infrared (MIR) images obtained with
8-10 m-class ground-based telescopes of a complete volume-limited (DL<40 Mpc)
sample of 24 Seyfert galaxies selected from the Swift/BAT nine month catalog.
We use those MIR images to study the nuclear and circumnuclear emission of the
galaxies. Using different methods to classify the MIR morphologies on scales of
~400 pc, we find that the majority of the galaxies (75-83%) are extended or
possibly extended and 17-25% are point-like. This extended emission is compact
and it has low surface brightness compared with the nuclear emission, and it
represents, on average, ~30% of the total MIR emission of the galaxies in the
sample. We find that the galaxies whose circumnuclear MIR emission is dominated
by star formation show more extended emission (650+-700 pc) than AGN-dominated
systems (300+-100 pc). In general, the galaxies with point-like MIR
morphologies are face-on or moderately inclined (b/a~0.4-1.0), and we do not
find significant differences between the morphologies of Sy1 and Sy2. We used
the nuclear and circumnuclear fluxes to investigate their correlation with
different AGN and SF activity indicators. We find that the nuclear MIR emission
(the inner ~70 pc) is strongly correlated with the X-ray emission (the harder
the X-rays the better the correlation) and with the [O IV] lambda 25.89 micron
emission line, indicating that it is AGN-dominated. We find the same results,
although with more scatter, for the circumnuclear emission, which indicates
that the AGN dominates the MIR emission in the inner ~400 pc of the galaxies,
with some contribution from star formation.Comment: 27 pages, 12 figures, accepted by MNRA
SHARDS: Constraints on the dust attenuation law of star-forming galaxies at z~2
We make use of SHARDS, an ultra-deep (<26.5AB) galaxy survey that provides
optical photo-spectra at resolution R~50, via medium band filters (FWHM~150A).
This dataset is combined with ancillary optical and NIR fluxes to constrain the
dust attenuation law in the rest-frame NUV region of star-forming galaxies
within the redshift window 1.5<z<3. We focus on the NUV bump strength (B) and
the total-to-selective extinction ratio (Rv), targeting a sample of 1,753
galaxies. By comparing the data with a set of population synthesis models
coupled to a parametric dust attenuation law, we constrain Rv and B, as well as
the colour excess, E(B-V). We find a correlation between Rv and B, that can be
interpreted either as a result of the grain size distribution, or a variation
of the dust geometry among galaxies. According to the former, small dust grains
are associated with a stronger NUV bump. The latter would lead to a range of
clumpiness in the distribution of dust within the interstellar medium of
star-forming galaxies. The observed wide range of NUV bump strengths can lead
to a systematic in the interpretation of the UV slope () typically used
to characterize the dust content. In this study we quantify these variations,
concluding that the effects are ~0.4.Comment: 13 pages, 11+2 figures, 3 tables. MNRAS, in pres
A census of very-low-mass stars and brown dwarfs in the sigma Orionis cluster
(ABRIDGED) We have analysed the near-infrared photometric data from the
Fourth Data Release (DR4) of the UKIRT Infrared Deep Sky Suvey (UKIDSS)
Galactic Clusters Survey (GCS) to derive the cluster luminosity and mass
functions, evaluate the extent of the cluster, and study the distribution and
variability of low-mass stars and brown dwarfs down to the deuterium-burning
limit. We have recovered most of the previously published members and found a
total of 287 candidate members within the central 30 arcmin in the 0.5-0.009
Msun mass range, including new objects not previously reported in the
literature. This new catalogue represents a homogeneous dataset of brown dwarf
member candidates over the central 30 arcmin of the cluster. The expected
photometric contamination by field objects with similar magnitudes and colours
to sigma Orionis members is ~15%. We present evidence of variability at the
99.5% confidence level over ~yearly timescales in 10 member candidates that
exhibit signs of youth and the presence of disks. The level of variability is
low (<0.3 mag) and does not impact the derivation of the cluster luminosity and
mass functions. Furthermore, we find a possible dearth of brown dwarfs within
the central five arcmin of the cluster, which is not caused by a lower level of
photometric sensitivity around the massive, O-type multiple star sigma Ori in
the GCS survey. Using state-of-the-art theoretical models, we derived the
luminosity and mass functions within the central 30 arcmin from the cluster
centre, with completeness down to J = 19 mag, corresponding to masses ranging
from 0.5 Msun down to the deuterium-burning mass boundary (~0.013 Msun). The
mass function of sigma Orionis in this mass interval shows a power law index
alpha = 0.5+/-0.2.Comment: 16 pages, 10 figures, 4 Tables, and appendix containing 6 tables
including tables in electronic format only. Revised version corrected for
english. Table 4 has been updated and correcte
Nuclear effects in (anti)neutrino charged-current quasielastic scattering at MINERνA kinematics
We compare the characteristics of the charged-current quasielastic neutrino and antineutrino scattering obtained in two different nuclear models, the phenomenological SuperScaling Approximation and the model using a realistic spectral function S(p, epsilon) that gives a scaling function in accordance with the (e, e') scattering data, with the recent data published by the MINER nu A Collaboration. The spectral function accounts for the nucleon-nucleon (NN) correlations by using natural orbitals from the Jastrow correlation method and has a realistic energy dependence. Both models provide a good description of the data without the need of an ad hoc increase of the value of the mass parameter in the axial-vector dipole form factor
Planck 2018 results: XII. Galactic astrophysics using polarized dust emission
Observations of the submillimetre emission from Galactic dust, in both total intensity I and polarization, have received tremendous interest thanks to the Planck full-sky maps. In this paper we make use of such full-sky maps of dust polarized emission produced from the third public release of Planck data. As the basis for expanding on astrophysical studies of the polarized thermal emission from Galactic dust, we present full-sky maps of the dust polarization fraction p, polarization angle ?, and dispersion function of polarization angles ??. The joint distribution (one-point statistics) of p and NH confirms that the mean and maximum polarization fractions decrease with increasing NH. The uncertainty on the maximum observed polarization fraction, pmax = 22.0?1.4+3.5% at 353 GHz and 80? resolution, is dominated by the uncertainty on the Galactic emission zero level in total intensity, in particular towards diffuse lines of sight at high Galactic latitudes. Furthermore, the inverse behaviour between p and ?? found earlier is seen to be present at high latitudes. This follows the ?????p?1 relationship expected from models of the polarized sky (including numerical simulations of magnetohydrodynamical turbulence) that include effects from only the topology of the turbulent magnetic field, but otherwise have uniform alignment and dust properties. Thus, the statistical properties of p, ?, and ?? for the most part reflect the structure of the Galactic magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map ???Ă—?p, looking for residual trends. While the polarization fraction p decreases by a factor of 3?4 between NH?=?1020?cm?2 and NH?=?2?Ă—?1022?cm?2, out of the Galactic plane, this product ???Ă—?p only decreases by about 25%. Because ?? is independent of the grain alignment efficiency, this demonstrates that the systematic decrease in p with NH is determined mostly by the magnetic-field structure and not by a drop in grain alignment. This systematic trend is observed both in the diffuse interstellar medium (ISM) and in molecular clouds of the Gould Belt. Second, we look for a dependence of polarization properties on the dust temperature, as we would expect from the radiative alignment torque (RAT) theory. We find no systematic trend of ???Ă—?p with the dust temperature Td, whether in the diffuse ISM or in the molecular clouds of the Gould Belt. In the diffuse ISM, lines of sight with high polarization fraction p and low polarization angle dispersion ?? tend, on the contrary, to have colder dust than lines of sight with low p and high ??. We also compare the Planck thermal dust polarization with starlight polarization data in the visible at high Galactic latitudes. The agreement in polarization angles is remarkable, and is consistent with what we expect from the noise and the observed dispersion of polarization angles in the visible on the scale of the Planck beam. The two polarization emission-to-extinction ratios, RP/p and RS/V, which primarily characterize dust optical properties, have only a weak dependence on the column density, and converge towards the values previously determined for translucent lines of sight. We also determine an upper limit for the polarization fraction in extinction, pV/E(B???V), of 13% at high Galactic latitude, compatible with the polarization fraction p???20% observed at 353 GHz. Taken together, these results provide strong constraints for models of Galactic dust in diffuse gas
Constraints in modeling the quasielastic response in inclusive lepton-nucleus scattering
We show that the quasielastic (QE) response calculated with the superscaling approach (SuSAv2) model, that relies on the scaling phenomenon observed in the analysis of (e,e′) data and on the relativistic mean-field theory, is very similar to that from a relativistic distorted-wave impulse approximation model when only the real part of the optical potentials is employed. The coincidence between the results from these two completely independent approaches, which satisfactorily agree with the inclusive data, reinforces the reliability of the quasielastic predictions stemming from both models and sets constraints for the QE response. We also study the low-energy and momentum-transfer region of the inclusive response by confronting the results of the relativistic mean-field model with those of the Hartree-Fock continuum random-phase approximation model, which accounts for nuclear long-range correlations. Finally, we present a comparison of our results with the recent Jefferson Laboratory (JLab) (e,e′) data for argon, titanium, and carbon, finding good agreement with the three data sets.Spanish Ministerio de Economia y Competitividad and European Regional Development Fund) FIS2017-88410-PJunta de Andalucia FQM 160, SOMM17/6105/UGRConsolider-Ingenio 2000 program CPAN (CSD2007-0042)Spanish Government (FPA2015-65035P and RTI2018-098868-B-I00
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