2,275 research outputs found
Translation, cross-cultural adaptation, and validation of a Dutch version of the actions and feelings questionnaire in autistic and neurotypical adult
The actions and feelings questionnaire (AFQ) provides a short, self-report measure of how well someone uses and understands visual communicative signals such as gestures. The objective of this study was to translate and cross-culturally adapt the AFQ into Dutch (AFQ-NL) and validate this new version in neurotypical and autistic populations. Translation and adaptation of the AFQ consisted of forward translation, synthesis, back translation, and expert review. In order to validate the AFQ-NL, we assessed convergent and divergent validity. We additionally assessed internal consistency using Cronbachâs alpha. Validation and reliability outcomes were all satisfactory. The AFQ-NL is a valid adaptation that can be used for both autistic and neurotypical populations in the Netherlands
Condensation in randomly perturbed zero-range processes
The zero-range process is a stochastic interacting particle system that
exhibits a condensation transition under certain conditions on the dynamics. It
has recently been found that a small perturbation of a generic class of jump
rates leads to a drastic change of the phase diagram and prevents condensation
in an extended parameter range. We complement this study with rigorous results
on a finite critical density and quenched free energy in the thermodynamic
limit, as well as quantitative heuristic results for small and large noise
which are supported by detailed simulation data. While our new results support
the initial findings, they also shed new light on the actual (limited)
relevance in large finite systems, which we discuss via fundamental diagrams
obtained from exact numerics for finite systems.Comment: 18 pages, 6 figure
Stability transitions for axisymmetric relative equilibria of Euclidean symmetric Hamiltonian systems
In the presence of noncompact symmetry, the stability of relative equilibria
under momentum-preserving perturbations does not generally imply robust
stability under momentum-changing perturbations. For axisymmetric relative
equilibria of Hamiltonian systems with Euclidean symmetry, we investigate
different mechanisms of stability: stability by energy-momentum confinement,
KAM, and Nekhoroshev stability, and we explain the transitions between these.
We apply our results to the Kirchhoff model for the motion of an axisymmetric
underwater vehicle, and we numerically study dissipation induced instability of
KAM stable relative equilibria for this system.Comment: Minor revisions. Typographical errors correcte
Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study
Vitamin K-dependent proteins, including matrix Gla-protein, have been
shown to inhibit vascular calcification. Activation of these proteins via
carboxylation depends on the availability of vitamin K. We examined
whether dietary intake of phylloquinone (vitamin K-1) and menaquinone
(vitamin K-2) were related to aortic calcification and coronary heart
disease (CHD) in the population-based Rotterdam Study. The analysis
included 4807 subjects with dietary data and no history of myocardial
infarction at baseline (1990-1993) who were followed until January 1,
2000. The risk of incident CHD, all-cause mortality, and aortic
atherosclerosis was studied in tertiles of energy-adjusted vitamin K
intake after adjustment for age, gender, BMI, smoking, diabetes,
education, and dietary factors. The relative risk (RR) of CHD mortality
was reduced in the mid and upper tertiles of dietary menaquinone compared
to the lower tertile [RR = 0.73 (95% CI: 0.45, 1.17) and 0.43 (0.24,
0.77), respectively]. Intake of menaquinone was also inversely related to
all-cause mortality [RR = 0.91 (0.75, 1.09) and 0.74 (0.59, 0.92),
respectively] and severe aortic calcification [odds ratio of 0.71 (0.50,
1.00) and 0.48 (0.32, 0.71), respectively]. Phylloquinone intake was not
related to any of the outcomes. These findings suggest tha
Population and Coherence Dynamics in Light Harvesting Complex II (LH2)
The electronic excitation population and coherence dynamics in the
chromophores of the photosynthetic light harvesting complex 2 (LH2) B850 ring
from purple bacteria (Rhodopseudomonas acidophila) have been studied
theoretically at both physiological and cryogenic temperatures. Similar to the
well-studied Fenna-Matthews-Olson (FMO) protein, oscillations of the excitation
population and coherence in the site basis are observed in LH2 by using a
scaled hierarchical equation of motion (HEOM) approach. However, this
oscillation time (300 fs) is much shorter compared to the FMO protein (650 fs)
at cryogenic temperature. Both environment and high temperature are found to
enhance the propagation speed of the exciton wave packet yet they shorten the
coherence time and suppress the oscillation amplitude of coherence and the
population. Our calculations show that a long-lived coherence between
chromophore electronic excited states can exist in such a noisy biological
environment.Comment: 21 pages, 9 figure
Global columnâaveraged methane mixing ratios from 2003 to 2009 as derived from SCIAMACHY: Trends and variability
After a decade of stable or slightly decreasing global methane concentrations, ground-based in situ data show that CH_4 began increasing again in 2007 and that this increase continued through 2009. So far, space-based retrievals sensitive to the lower troposphere in the time period under consideration have not been available. Here we report a long-term data set of column-averaged methane mixing ratios retrieved from spectra of the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instrument onboard Envisat. The retrieval quality after 2005 was severely affected by degrading detector pixels within the methane 2Îœ_3 absorption band. We identified the most crucial problems in SCIAMACHY detector degradation and overcame the problem by applying a strict pixel mask as well as a new dark current characterization. Even though retrieval precision after the end of 2005 is invariably degraded, consistent methane retrievals from 2003 through 2009 are now possible. Regional time series in the Sahara, Australia, tropical Africa, South America, and Asia show the methane increase in 2007â2009, but we cannot yet draw a firm conclusion concerning the origin of the increase. Tropical Africa even seems to exhibit a negative anomaly in 2006, but an impact from changes in SCIAMACHY detector degradation cannot be excluded yet. Over Assakrem, Algeria, we observed strong similarities between SCIAMACHY measurements and ground-based data in deseasonalized time series. We further show long-term SCIAMACHY xCH_4 averages at high spatial resolution that provide further insight into methane variations on regional scales. The Red Basin in China exhibits, on average, the highest methane abundance worldwide, while other localized features such as the Sudd wetlands in southern Sudan can also be identified in SCIAMACHY xCH_4 averages
Heretability and Correlation of Vegetative and Generative Character on Genotypes of Jatropha (Jatropha curcas Linn.)
AbstractThis study was aimed to obtain information of heritability predictive value and correlations of vegetative and generative characters on six genotypes of J. curcas. The characters of plant height, leaf number, leaf width, number of primary and secondary branches, number of fruit bunches, number of fruits per plant, seed's and 100 seedsâ dry weight showed high predictive value of heritability. Characters related to positive correlation and high heritability values (leaf width, number of primary branches, number of secondary branches, number of fruit bunches, number of fruits per plant) are able to be used as criteria for selection of J. curcas plant
Sub-electron Charge Relaxation via 2D Hopping Conductors
We have extended Monte Carlo simulations of hopping transport in completely
disordered 2D conductors to the process of external charge relaxation. In this
situation, a conductor of area shunts an external capacitor
with initial charge . At low temperatures, the charge relaxation process
stops at some "residual" charge value corresponding to the effective threshold
of the Coulomb blockade of hopping. We have calculated the r.m.s value
of the residual charge for a statistical ensemble of capacitor-shunting
conductors with random distribution of localized sites in space and energy and
random , as a function of macroscopic parameters of the system. Rather
unexpectedly, has turned out to depend only on some parameter
combination: for negligible Coulomb interaction
and for substantial interaction. (Here
is the seed density of localized states, while is the
dielectric constant.) For sufficiently large conductors, both functions
follow the power law , but with different
exponents: for negligible and
for significant Coulomb interaction. We have been able to derive this law
analytically for the former (most practical) case, and also explain the scaling
(but not the exact value of the exponent) for the latter case. In conclusion,
we discuss possible applications of the sub-electron charge transfer for
"grounding" random background charge in single-electron devices.Comment: 12 pages, 5 figures. In addition to fixing minor typos and updating
references, the discussion has been changed and expande
Vanishing Twist near Focus-Focus Points
We show that near a focus-focus point in a Liouville integrable Hamiltonian
system with two degrees of freedom lines of locally constant rotation number in
the image of the energy-momentum map are spirals determined by the eigenvalue
of the equilibrium. From this representation of the rotation number we derive
that the twist condition for the isoenergetic KAM condition vanishes on a curve
in the image of the energy-momentum map that is transversal to the line of
constant energy. In contrast to this we also show that the frequency map is
non-degenerate for every point in a neighborhood of a focus-focus point.Comment: 13 page
Simultaneous X-ray and Ultraviolet spectroscopy of the Seyfert galaxy NGC 5548. III. X-ray time variability
The Seyfert 1 galaxy NGC 5548 was observed for a week by Chandra using both
the HETGS and LETGS spectrometers. In this paper we study the time variability
of the continuum radiation. During our observation, the source showed a gradual
increase in flux over four days, followed by a rapid decrease and flattening of
the light curve afterwards. Superimposed upon these relatively slow variations
several short duration bursts or quasi-periodic oscillations occured with a
typical duration of several hours and separation between 0.6-0.9 days. The
bursts show a delay of the hard X-rays with respect to the soft X-rays of a few
hours. We interprete these bursts as due to a rotating, fluctuating hot spot at
approximately 10 gravitational radii; the time delay of the hard X-rays from
the bursts agree with the canonical picture of Inverse Compton scattering of
the soft accretion disk photons on a hot medium that is relatively close to the
central black hole.Comment: 6 pages, 7 figures, accepted for publication in Astronomy and
Astrophysic
- âŠ