461 research outputs found
Deadlocks and waiting times in traffic jam
In a city of right moving and upmoving cars with hardcore constraint, traffic
jam occurs in the form of bands. We show how the bands are destroyed by a small
number of strictly left moving cars yielding a deadlock phase with a rough edge
of left cars. We also show that the probability of waiting time at a signal for
a particular tagged car has a power law dependence on time, indicating the
absence of any characteristic time scale for an emergent traffic jam. The
exponent is same for both the band and the deadlock cases. The significances of
these results are discussed.Comment: 8 pages including 4 eps figures, one in colour, uses revtex to appear
in Physica
Validity of a four-factor modelunderlying the physical fitness in adults with intellectual disabilities a confirmatory factor analysis
Purpose: To use confirmatory factor analysis to test whether a four factor might explain the clustering of the components of the physical fitness in adults with intellectual disabilities (FID).
Relevance: Individuals with intellectual disabilities (ID) are significantly weaker than individuals without ID at all stages of life. These subjects might be particularly susceptible to loss of basic function because of poor physical fitness.
Participants: We studied 267 adults with intellectual disability of the Spanish Special Olympics Games.
Methods: The four-factor model included: the flexibility, the strength, the balance and the cardiorespiratory endurance with 9 variables of the fitness assessment.
Analysis: The construct validity of the model was assessed through the factor loadings, interpreted as the correlation between the variables in the model and their underlying factor, which is the FID construct.
Results: Factor loading were 0,55 for the passive knee extension, o,52 for Functional shoulder rotation, −0.71 for the timed-stand test, 0.58 for the grip test, 0.75 the single leg stance with eyes open, 0.69 single leg stance with eyes closed, 0.72 for the resting heart rate, 0.56 for the two-minute step test (2MST) 0,97 for 2 minutes after finish 2MST. The four-factor model also showed a good fit to the data, as indicated by a high comparative fit index (CFI=0,93) and a low standardized root mean square residual (SRMR=0,072)
Conclusions: A four underlying factor has shown acceptable validity to represent FID
Implications: The new model of FID can offer understanding better these construct in this special populationUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The evolution of enzyme function in the isomerases.
The advent of computational approaches to measure functional similarity between enzymes adds a new dimension to existing evolutionary studies based on sequence and structure. This paper reviews research efforts aiming to understand the evolution of enzyme function in superfamilies, presenting a novel strategy to provide an overview of the evolution of enzymes belonging to an individual EC class, using the isomerases as an exemplar
Status of the ANAIS Dark Matter Project at the Canfranc Underground Laboratory
The ANAIS experiment aims at the confirmation of the DAMA/LIBRA signal. A
detailed analysis of two NaI(Tl) crystals of 12.5 kg each grown by Alpha
Spectra will be shown: effective threshold at 1 keVee is at reach thanks to
outstanding light collection and robust PMT noise filtering protocols and the
measured background is well understood down to 3 keVee, having quantified K, U
and Th content and cosmogenic activation in the crystals. A new detector was
installed in Canfranc in March 2015 together with the two previous modules and
preliminary characterization results will be presented. Finally, the status and
expected sensitivity of the full experiment with 112 kg will be reviewed.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs,
Zaragoza, June 22 to 26, 201
Background model of NaI(Tl) detectors for the ANAIS Dark Matter Project
A thorough understanding of the background sources is mandatory in any
experiment searching for rare events. The ANAIS (Annual Modulation with NaI(Tl)
Scintillators) experiment aims at the confirmation of the DAMA/LIBRA signal at
the Canfranc Underground Laboratory (LSC). Two NaI(Tl) crystals of 12.5 kg each
produced by Alpha Spectra have been taking data since December 2012. The
complete background model of these detectors and more precisely in the region
of interest will be described. Preliminary background analysis of a new 12.5 kg
crystal received at Canfranc in March 2015 will be presented too. Finally, the
power of anticoincidence rejection in the region of interest has been analyzed
in a 4x 5 12.5 kg detector matrix.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs,
Zaragoza, June 22 to 26, 201
Production and relevance of cosmogenic radionuclides in NaI(Tl) crystals
The cosmogenic production of long-lived radioactive isotopes in materials is
an hazard for experiments demanding ultra-low background conditions. Although
NaI(Tl) scintillators have been used in this context for a long time, very few
activation data were available. We present results from two 12.5 kg NaI(Tl)
detectors, developed within the ANAIS project and installed at the Canfranc
Underground Laboratory. The prompt data taking starting made possible a
reliable quantification of production of some I, Te and Na isotopes with
half-lives larger than ten days. Initial activities underground were measured
and then production rates at sea level were estimated following the history of
detectors; a comparison of these rates with calculations using typical cosmic
neutron flux at sea level and a selected description of excitation functions
was also carried out. After including the contribution from the identified
cosmogenic products in the detector background model, we found that the
presence of 3H in the crystal bulk would help to fit much better our background
model and experimental data. We have analyzed the cosmogenic production of 3H
in NaI, and although precise quantification has not been attempted, we can
conclude that it could imply a very relevant contribution to the total
background below 15 keV in NaI detectors.Comment: Proceedings of the Low Radioactivity Techniques 2015 workshop, March
2015, Seattle (US
Analysis of backgrounds for the ANAIS-112 dark matter experiment
The ANAIS (Annual modulation with NaI(Tl) Scintillators) experiment aims at
the confirmation or refutation of theDAMA/LIBRA positive annual modulation
signal in the low energy detection rate, using the same target and technique,
at the Canfranc Underground Laboratory (LSC) in Spain. ANAIS-112, consisting of
nine 12.5 kg NaI(Tl) modules produced by Alpha Spectra Inc. in a 3x3matrix
configuration, is taking data smoothly in "dark matter search" mode since
August, 2017, after a commissioning phase and operation of the first detectors
during the last years in various setups. A large effort has been carried out
withinANAIS to characterize the background of sodium iodide detectors, before
unblinding the data and performing the first annual modulation analysis. Here,
the background models developed for all the nine ANAIS-112 detectors are
presented. Measured spectra from threshold to high energy in different
conditions are well described by the models based on quantified activities
independently estimated following several approaches. In the region from 1 to 6
keVee the measured, efficiency corrected background level is 3.58+-0.02 keV-1
kg-1 day-1; NaI crystal bulk contamination is the dominant background source
being 210Pb, 40K, 22Na and 3H contributions the most relevant ones. This
background level, added to the achieved 1 keVee analysis threshold (thanks to
the outstanding light collection and robust filtering procedures developed),
allow ANAIS-112 to be sensitive to the modulation amplitude measured by
DAMA/LIBRA, and able to explore at three sigma level in 5 years the WIMP
parameter region singled out by this experiment.Comment: Final version for publicatio
Four-port coupled channel-guide device based on 2D photonic crystal structure
We have fabricated and measured a four-port coupled channel-waveguide device using W1 channel waveguides oriented along ΓK directions in a two-dimensional (2D) hole-based planar photonic crystal (PhC) based on silicon-on-insulator (SOI) waveguide material, at operation wavelengths around 1550 nm. 2D FDTD simulations and experimental results are shown and compared. The structure has been designed using a mode conversion approach, combined with coupled-mode concepts. The overall length of the photonic crystal structure is typically about 39 μm and the structure has been fabricated using a combination of direct-write electron-beam lithography (EBL) and dry-etch processing. Devices were measured using a tunable laser with end-fire coupling into the planar structure
Methanol Dehydrogenation on Pt Electrodes : Active Sites and Role of Adsorbed Spectators Revealed through Time-Resolved ATR-SEIRAS
ACKNOWLEDGMENT L.P.-M. acknowledges a doctoral scholarship within the Leverhulme Centre for Doctoral Training in Sustainable Production of Chemicals and Materials (Grant DS-2017-073).Peer reviewedPostprin
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