11,404 research outputs found
Numerical study of barriers and valleys in the free-energy landscape of spin glasses
We study the problem of glassy relaxations in the presence of an external
field in the highly controlled context of a spin-glass simulation. We consider
a small spin glass in three dimensions (specifically, a lattice of size L=8,
small enough to be equilibrated through a Parallel Tempering simulations at low
temperatures, deep in the spin glass phase). After equilibrating the sample, an
external field is switched on, and the subsequent dynamics is studied. The
field turns out to reduce the relaxation time, but huge statistical
fluctuations are found when different samples are compared. After taking care
of these fluctuations we find that the expected linear regime is very narrow.
Nevertheless, when regarded as a purely numerical method, we find that the
external field is extremely effective in reducing the relaxation times.Comment: 22 pages, 10 figures; Published versio
¿Son el bajo nivel de condición física y la obesidad dos características del adolescente con síndrome de Down?
Introduction: “Obesity” is considered a feature of
youth with DS but whether “low physical fitness” is also a
feature is unknown.
Objective: The aim of this case-control study was to
compare the levels of fatness and fitness in adolescents
with and without DS.
Methods: Participants included 17 (5 girls) adolescents
with DS aged 12-18 years and a control group of 94 (45
girls) adolescents without DS aged 12-16 years. The
ALPHA health-related fitness test battery for children
and adolescents was selected to assess fatness and fitness
in both groups.
Results: There were no differences in levels of fatness
between groups (all P > 0.27). Adolescents with DS had
lower levels of fitness in all the tests than adolescents
without DS (all P < 0.001).
Conclusion: Adolescents with DS have similar levels of
fatness and lower levels of fitness than their peers without
DSIntroducción: La obesidad es considerada una característica
de los jóvenes con SD, sin embargo se desconoce si
la “baja condición física” también lo es.
Objetivo: Comparar los niveles de obesidad y condición
física en adolescentes con y sin SD.
Métodos: Participaron 17 adolescentes (5 niñas) con SD
de 12 a 18 años y un grupo control de 94 (45 niñas) adolescentes
sin SD de 12-16 años de edad. La batería de condición
física ALPHA relacionada con la salud para niños y
adolescentes fue seleccionada para evaluar la obesidad y
la condición física en ambos grupos.
Resultados: No se encontraron diferencias en los niveles
de obesidad entre grupos (P > 0,27). Los adolescentes
con SD tuvieron niveles más bajos de condición física en
todos los test en comparación con los adolescentes sin SD
(P < 0,001).
Conclusión: Los adolescentes con SD tienen niveles
similares de obesidad y menores de condición física que
sus compañeros sin SD.The UP&DOWN study was supported by the
Spanish Ministry of Economy and Competitiveness
(DEP 2010-21662-C04). JRR was supported by a
contract from the Spanish Ministry of Science and
Innovation (RYC-2010-05957
Early Science with the Large Millimeter Telescope: an energy-driven wind revealed by massive molecular and fast X-ray outflows in the Seyfert Galaxy IRAS 17020+4544
We report on the coexistence of powerful gas outflows observed in millimeter
and X-ray data of the Radio-Loud Narrow Line Seyfert 1 Galaxy IRAS 17020+4544.
Thanks to the large collecting power of the Large Millimeter Telescope, a
prominent line arising from the 12CO(1-0) transition was revealed in recent
observations of this source. The complex profile is composed by a narrow
double-peak line and a broad wing. While the double-peak structure may be
arising in a disk of molecular material, the broad wing is interpreted as the
signature of a massive outflow of molecular gas with an approximate bulk
velocity of -660 km/s. This molecular wind is likely associated to a
multi-component X-ray Ultra-Fast Outflow with velocities reaching up to ~0.1c
and column densities in the range 10^{21-23.9} cm^-2 that was reported in the
source prior to the LMT observations. The momentum load estimated in the two
gas phases indicates that within the observational uncertainties the outflow is
consistent with being propagating through the galaxy and sweeping up the gas
while conserving its energy. This scenario, which has been often postulated as
a viable mechanism of how AGN feedback takes place, has so far been observed
only in ULIRGs sources. IRAS 17020+4544 with bolometric and infrared luminosity
respectively of 5X10^{44} erg/s and 1.05X10^{11} L_sun appears to be an example
of AGN feedback in a NLSy1 Galaxy (a low power AGN). New proprietary
multi-wavelength data recently obtained on this source will allow us to
corroborate the proposed hypothesis.Comment: Accepted for publication on ApJ Letters, 9 pages, 4 figure
NICMOS Imaging of Molecular Hydrogen Emission in Seyfert Galaxies
We present NICMOS imaging of broad band and molecular hydrogen emission in
Seyfert galaxies. In 6 of 10 Seyferts we detect resolved or extended emission
in the 1-0 S(1) 2.121 or 1-0 S(3) 1.9570 micron molecular hydrogen lines. We
did not detect emission in the most distant galaxy or in the 2 Seyfert 1
galaxies in our sample because of the luminosity of the nuclear point sources.
In NGC 5643, NGC 2110 and MKN 1066, molecular hydrogen emission is detected in
the extended narrow line region on scales of a few hundred pc from the nucleus.
Emission is coincident with [OIII] and H alpha+[NII] line emission. This
emission is also near dust lanes observed in the visible to near-infrared color
maps suggesting that a multiphase medium exists near the ionization cones and
that the morphology of the line emission is dependent on the density of the
ambient media. The high 1-0 S(1) or S(3) H2 to H alpha flux ratio suggests that
shock excitation of molecular hydrogen (rather than UV fluorescence) is the
dominant excitation process in these extended features. In NGC 2992 and NGC
3227 the molecular hydrogen emission is from 800 and 100 pc diameter `disks'
(respectively) which are not directly associated with [OIII] emission and are
near high levels of extinction (AV > 10). In NGC 4945 the molecular hydrogen
emission appears to be from the edge of a 100 pc superbubble. In these 3
galaxies the molecular gas could be excited by processes associated with local
star formation. We confirm previous spectroscopic studies finding that no
single mechanism is likely to be responsible for the molecular hydrogen
excitation in Seyfert galaxies.Comment: submitted to Ap
The influence of road networks on brown bear spatial distribution and habitat suitability in a human-modified landscape
Roads are human infrastructure that heavily affect wildlife, often with marked
impacts on carnivores, including brown bears Ursus arctos. Here, we assessed the
potential impact of road networks on the distribution of brown bears in the small, isolated
and endangered Cantabrian population of north-western Spain. To ascertain
whether local road networks affect brown bear spatial distribution, we first assessed
potential influences on the distance of bear locations to roads using candidate models
which included topographic variables, landcover types, bear age and reproductive status,
traffic volume and road visibility. Then, we built two sets of habitat suitability
models, both with and without roads, to discern the possible loss of habitat suitability
caused by roads. The mean distance of bear locations to the nearest road was
968 804 m and the closest road was a low traffic road in 72.5% of cases. Candidate
models showed little influence of our variables on bear distance to the nearest
road, with the exception of elevation. Habitat suitability models revealed that road
networks in our study area seem to have almost no effect on brown bear habitat suitability,
except for females with yearlings during the denning season. However, this
result may also be a consequence of the fact that only a small proportion (16.5%) of
the cells classified as suitable bear habitats were crossed by roads, that is, most of the
roads are primarily located in unsuitable bear habitats in the Cantabrian Mountains.
Compared to previous studies conducted in other populations, mainly North American
ones, our findings might suggest a different response of Eurasian brown bears to
roads due to a longer bear-human coexistence in Europe versus North America. However,
the indirect approach used in our study does not exclude other detrimental
effects, for example, road mortality, increased stress and movement pattern disruption,
only detectable by more direct approaches such as telemetry
Monounsaturated fatty acids, olive oil and blood pressure: epidemiological, clinical and experimental evidence
Diet has an important role in the prevention and treatment of hypertension. In early
epidemiological studies, conducted mainly in the USA, monounsaturated fatty acids showed a deleterious association with blood pressure or no relationship at all.
However, more recent studies, conducted in Mediterranean countries, have shed new
light on this issue. In the present review we summarise the main results of
epidemiological studies and feeding trials, and explain the possible mechanisms
through which monounsaturated fatty acids, and specifically olive oil as the major
dietary source of this type of fat in Mediterranean countries, could exert a favourable effect on blood pressure
Novel Graphical Analyses of Runs of Homozygosity among Species and Livestock Breeds
peer-reviewedRuns of homozygosity (ROH), uninterrupted stretches of homozygous genotypes resulting from parents transmitting identical haplotypes to their offspring, have emerged as informative genome-wide estimates of autozygosity (inbreeding). We used genomic profiles based on 698 K single nucleotide polymorphisms (SNPs) from nine breeds of domestic cattle (Bos taurus) and the European bison (Bison bonasus) to investigate how ROH distributions can be compared within and among species. We focused on two length classes: 0.5–15 Mb to investigate ancient events and >15 Mb to address recent events (approximately three generations). For each length class, we chose a few chromosomes with a high number of ROH, calculated the percentage of times a SNP appeared in a ROH, and plotted the results. We selected areas with distinct patterns including regions where (1) all groups revealed an increase or decrease of ROH, (2) bison differed from cattle, (3) one cattle breed or groups of breeds differed (e.g., dairy versus meat cattle). Examination of these regions in the cattle genome showed genes potentially important for natural and human-induced selection, concerning, for example, meat and milk quality, metabolism, growth, and immune function. The comparative methodology presented here permits visual identification of regions of interest for selection, breeding programs, and conservation.Cino Pertoldi was supported by a grant from Danish Natural Science Research Council (Grant nos. 11-103926, 09-065999, and 95095995), the Carlsberg Foundation (Grant no. 2011-
01-0059), and the Aalborg Zoo Conservation Foundation (AZCF). Laura Iacolina has received funding from the European Union’s Horizon 2020 research and innovation programme
under the Marie Sklodowska-Curie Action (Grant
Agreement no. 656697). Astrid V. Stronen received funding from the Danish Natural Science Research Council (Postdoctoral Grant 1337-00007)
Correlates of ideal cardiovascular health in European adolescents: The HELENA study
Background and aims: The ideal cardiovascular health (iCVH) construct consists of 4 health behaviors (smoking status, body mass index, physical activity and diet) and 3 health factors (total cholesterol, blood pressure and fasting glucose). A greater number of iCVH components in adolescence are related to better cardiovascular health, but little is known about the correlates of iCVH in adolescents. Thus, the aim of the study was to examine correlates of iCVH in European adolescents.
Methods and results: The study comprised 637 European adolescents with complete iCVH data. Participants were part of the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, a cross-sectional, multicenter study conducted in 9 different European countries. Correlates investigated were sex and age, family affluence scale, maternal education, geographic location, sleep time, television viewing, duration of pregnancy, birth weight and breastfeeding. Younger adolescents, those whose mothers had medium/high education or those whowatched television less than 2 h per day had a greater number of iCVH components compared to those who were older, had a mother with low education or watched television 2 h or more daily (P <= 0.01).
Conclusion: Since in our study older adolescents had worse iCVH than younger adolescents, early promotion of cardiovascular health may be important. Future studies mayalso investigate the usefulness of limiting television viewing to promote iCVH. Finally, since adolescents of mothers with low education had poorer iCVH, it may be of special interest to tailor public health promotion to adolescents from families with low socioeconomic status
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