18,281 research outputs found
The AMBRE Project: Stellar Parameterisation of the ESO:UVES archived spectra
The AMBRE Project is a collaboration between the European Southern
Observatory (ESO) and the Observatoire de la Cote d'Azur (OCA) that has been
established in order to carry out the determination of stellar atmospheric
parameters for the archived spectra of four ESO spectrographs.
The analysis of the UVES archived spectra for their stellar parameters has
been completed in the third phase of the AMBRE Project. From the complete
ESO:UVES archive dataset that was received covering the period 2000 to 2010,
51921 spectra for the six standard setups were analysed. The AMBRE analysis
pipeline uses the stellar parameterisation algorithm MATISSE to obtain the
stellar atmospheric parameters. The synthetic grid is currently constrained to
FGKM stars only.
Stellar atmospheric parameters are reported for 12,403 of the 51,921 UVES
archived spectra analysed in AMBRE:UVES. This equates to ~23.9% of the sample
and ~3,708 stars. Effective temperature, surface gravity, metallicity and alpha
element to iron ratio abundances are provided for 10,212 spectra (~19.7%),
while at least effective temperature is provided for the remaining 2,191
spectra. Radial velocities are reported for 36,881 (~71.0%) of the analysed
archive spectra. Typical external errors of sigmaTeff~110dex,
sigmalogg~0.18dex, sigma[M/H]~0.13dex, and sigma[alpha/Fe]~0.05dex with some
reported variation between giants and dwarfs and between setups are reported.
UVES is used to observe an extensive collection of stellar and non-stellar
objects all of which have been included in the archived dataset provided to OCA
by ESO. The AMBRE analysis extracts those objects which lie within the FGKM
parameter space of the AMBRE slow rotating synthetic spectra grid. Thus by
homogeneous blind analysis AMBRE has successfully extracted and parameterised
the targeted FGK stars (23.9% of the analysed sample) from within the ESO:UVES
archive.Comment: 19 pages, 16 figures, 11 table
Fluctuation Analysis of Human Electroencephalogram
The scaling behaviors of the human electroencephalogram (EEG) time series are
studied using detrended fluctuation analysis. Two scaling regions are found in
nearly every channel for all subjects examined. The scatter plot of the scaling
exponents for all channels (up to 129) reveals the complicated structure of a
subject's brain activity. Moment analyses are performed to extract the gross
features of all the scaling exponents, and another universal scaling behavior
is identified. A one-parameter description is found to characterize the
fluctuation properties of the nonlinear behaviors of the brain dynamics.Comment: 4 pages in RevTeX + 6 figures in ep
Significant differences in incubation times in sheep infected with bovine spongiform encephalopathy result from variation at codon 141 in the PRNP gene
The susceptibility of sheep to prion infection is linked to variation in the PRNP gene, which
encodes the prion protein. Common polymorphisms occur at codons 136, 154 and 171. Sheep
which are homozygous for the A<sub>136</sub>R<sub>154</sub>Q<sub>171</sub> allele are the most susceptible to bovine spongiform
encephalopathy (BSE). The effect of other polymorphisms on BSE susceptibility is unknown. We
orally infected ARQ/ARQ Cheviot sheep with equal amounts of BSE brain homogenate and a
range of incubation periods was observed. When we segregated sheep according to the amino
acid (L or F) encoded at codon 141 of the PRNP gene, the shortest incubation period was
observed in LL141 sheep, whilst incubation periods in FF<sub>141</sub> and LF<sub>141</sub> sheep were significantly
longer. No statistically significant differences existed in the expression of total prion protein or the
disease-associated isoform in BSE-infected sheep within each genotype subgroup. This
suggested that the amino acid encoded at codon 141 probably affects incubation times through
direct effects on protein misfolding rates
Spectroscopic search for binaries among EHB stars in globular clusters
We performed a spectroscopic search for binaries among hot Horizontal Branch
stars in globular clusters. We present final results for a sample of 51 stars
in NGC6752, and preliminary results for the first 15 stars analyzed in M80. The
observed stars are distributed along all the HBs in the range 8000 < Teff <
32000 K, and have been observed during four nights. Radial velocity variations
have been measured with the cross-correlation technique. We carefully analyzed
the statistical and systematic errors associated with the measurements in order
to evaluate the statistical significance of the observed variations. No close
binary system has been detected, neither among cooler stars nor among the
sample of hot EHB stars (18 stars with Teff > 22000 K in NGC6752). The data
corrected for instrumental effects indicate that the radial velocity variations
are always below the 3sigma level of ~15 km/s. These results are in sharp
contrast with those found for field hot subdwarfs, and open new questions about
the formation of EHB stars in globular clusters, and possibly of the field
subdwarfs.Comment: To appear in Baltic Astronomy. Proceedings of the 2nd meeting on Hot
Subdwarf Stars, La Palma, June 2005. 4 pages, 2 figure
Stationary states of a spherical Minority Game with ergodicity breaking
Using generating functional and replica techniques, respectively, we study
the dynamics and statics of a spherical Minority Game (MG), which in contrast
with a spherical MG previously presented in J.Phys A: Math. Gen. 36 11159
(2003) displays a phase with broken ergodicity and dependence of the
macroscopic stationary state on initial conditions. The model thus bears more
similarity with the original MG. Still, all order parameters including the
volatility can computed in the ergodic phases without making any
approximations. We also study the effects of market impact correction on the
phase diagram. Finally we discuss a continuous-time version of the model as
well as the differences between on-line and batch update rules. Our analytical
results are confirmed convincingly by comparison with numerical simulations. In
an appendix we extend the analysis of the earlier spherical MG to a model with
general time-step, and compare the dynamics and statics of the two spherical
models.Comment: 26 pages, 8 figures; typo correcte
Risk and protective factors for release in outpatients with schizophrenia
eposterWe aim to determine risk and protective factors influencing relapse incidence in outpatient with schizophrenia.
A longitudinal, observational study was done with outpatients with schizophrenia (F20) or schizoaffective disorder (F25)(DMS-IV and ICD-10), without hospitalization during the previous 6 months. The patients were consecutively included into the study to received oral (O-A) or long-acting injectable (depot-A) antipsychotics. Clinical stage evolution, compliance, efficacy and safety assessments (including PANSS, CGI-SSI, hospitalization rates, and adverse events) were recorded before and after 6 and 12 months of treatment.
Results: 60 outpatients (aged 34.5±8.9, male 73%), 75% schizophrenia and 25% schizoaffective disorder diagnosis, 68.3% fewer than 15 years of schizophrenia evolution, 76.7% fewer than 5 times previous hospitalizations were treated with O-A (41.7%) or depot-A (58.3%) antipsychotics for at least one year. Depot-A treated patients showed a significant higher compliance compared to O-A patients during the all following time, lower PANSS (total, positive and negative) scores and CGI-SSI score (p<0.01), and a delayed relapse incidence and re-hospitalization to more than 1 year in the 48% of patients (relapse % depot/% oral) after 6 months 22.9%/52.0%, and after 12 months 48.6%/4.0%.
Conclusion: There were protective factors which delayed relapse incidence in schizophrenia: Use of sustained-release preparations, family support. There were risk factors for occurrence of relapse in schizophrenia: cocaine, heroin and alcohol consumption, absence of family support, greater severity of patients assessed through CGI-SI, male sex, age older than 25 years and long-term evolution of the disorder.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Contribución al estudio de la distribución de Cetáceos en el Mediterráneo y Atlántico Ibérico
Magnetic ordering in GdNi2B2C revisited by resonant x-ray scattering: evidence for the double-q model
Recent theoretical efforts aimed at understanding the nature of
antiferromagnetic ordering in GdNi2B2C predicted double-q ordering. Here we
employ resonant elastic x-ray scattering to test this theory against the
formerly proposed, single-q ordering scenario. Our study reveals a satellite
reflection associated with a mixed-order component propagation wave vector,
viz., (q_a,2q_b,0) with q_b = q_a approx= 0.55 reciprocal lattice units, the
presence of which is incompatible with single-q ordering but is expected from
the double-q model. A (3q_a,0,0) wave vector (i.e., third-order) satellite is
also observed, again in line with the double-q model. The temperature
dependencies of these along with that of a first-order satellite are compared
with calculations based on the double-q model and reasonable qualitative
agreement is found. By examining the azimuthal dependence of first-order
satellite scattering, we show the magnetic order to be, as predicted,
elliptically polarized at base temperature and find the temperature dependence
of the "out of a-b plane" moment component to be in fairly good agreement with
calculation. Our results provide qualitative support for the double-q model and
thus in turn corroborate the explanation for the "magnetoelastic paradox"
offered by this model.Comment: 8 pages, 5 figures. Submitted to Phys. Rev.
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