4,070 research outputs found
Grammar-Based Geodesics in Semantic Networks
A geodesic is the shortest path between two vertices in a connected network.
The geodesic is the kernel of various network metrics including radius,
diameter, eccentricity, closeness, and betweenness. These metrics are the
foundation of much network research and thus, have been studied extensively in
the domain of single-relational networks (both in their directed and undirected
forms). However, geodesics for single-relational networks do not translate
directly to multi-relational, or semantic networks, where vertices are
connected to one another by any number of edge labels. Here, a more
sophisticated method for calculating a geodesic is necessary. This article
presents a technique for calculating geodesics in semantic networks with a
focus on semantic networks represented according to the Resource Description
Framework (RDF). In this framework, a discrete "walker" utilizes an abstract
path description called a grammar to determine which paths to include in its
geodesic calculation. The grammar-based model forms a general framework for
studying geodesic metrics in semantic networks.Comment: First draft written in 200
Chiral properties of hematite ({\alpha}-Fe2O3) inferred from resonant Bragg diffraction using circularly polarized x-rays
Chiral properties of the two phases - collinear motif (below Morin transition
temperature, TM=250 K) and canted motif (above TM) - of magnetically ordered
hematite ({\alpha}-Fe2O3) have been identified in single crystal resonant x-ray
Bragg diffraction, using circular polarized incident x-rays tuned near the iron
K-edge. Magneto-electric multipoles, including an anapole, fully characterize
the high-temperature canted phase, whereas the low-temperature collinear phase
supports both parity-odd and parity-even multipoles that are time-odd. Orbital
angular momentum accompanies the collinear motif, while it is conspicuously
absent with the canted motif. Intensities have been successfully confronted
with analytic expressions derived from an atomic model fully compliant with
chemical and magnetic structures. Values of Fe atomic multipoles previously
derived from independent experimental data, are shown to be completely
trustworthy
On the Cauchy problem for a nonlinearly dispersive wave equation
We establish the local well-posedness for a new nonlinearly dispersive wave
equation and we show that the equation has solutions that exist for indefinite
times as well as solutions which blowup in finite times. Furthermore, we derive
an explosion criterion for the equation and we give a sharp estimate from below
for the existence time of solutions with smooth initial data.Comment: arxiv version is already officia
Factorial Invariance of Self-efficacy in Physical Health Care Scale for Men and Women University Students
The present study analyses the psychometric properties of the Selfefficacy in Physical Health Care Scale. The overall sample consisted of 2006 subjects: 902 women and 1104 men, with a mean age of 18.53 years (SD= 1.52) and 18.84 years (SD= 1.55) respectively. The Factorial Psychometric analysis showed that a three-factorial structure (nutrition, physical health and hydration) was viable and adequate for both populations (men and woman) according to the established psychometric requirements when the informers are the students themselves. The results showed that factor structure, factor loadings and intercepts of the instrument could be considered invariant across groups; however, there are differences between groups in favor of men for the means of the nutrition and physical health factors
Incidents control in radiotherapy oncology
Primer pla de l'escut del monarca del s. XVI,
conservat i ubicat a la porta de la UB. Mesura
1,60 x 2,20 metre si Ă©s de pedra sorrenca
Stability of childhood anxiety disorder diagnoses: a follow-up naturalistic study in psychiatric care
Few studies have examined the stability of major psychiatric disorders in pediatric psychiatric clinical populations. The objective of this study was to examine the long-term stability of anxiety diagnoses starting with pre-school age children through adolescence evaluated at multiple time points. Prospective cohort study was conducted of all children and adolescents receiving psychiatric care at all pediatric psychiatric clinics belonging to two catchment areas in Madrid, Spain, between 1 January, 1992 and 30 April, 2006. Patients were selected from among 24,163 children and adolescents who received psychiatric care. Patients had to have a diagnosis of an ICD-10 anxiety disorder during at least one of the consultations and had to have received psychiatric care for the anxiety disorder. We grouped anxiety disorder diagnoses according to the following categories: phobic disorders, social anxiety disorders, obsessive–compulsive disorder (OCD), stress-related disorders, and "other" anxiety disorders which, among others, included generalized anxiety disorder, and panic disorder. Complementary indices of diagnostic stability were calculated. As much as 1,869 subjects were included and had 27,945 psychiatric/ psychological consultations. The stability of all ICD-10 anxiety disorder categories studied was high regardless of the measure of diagnostic stability used. Phobic and social anxiety disorders showed the highest diagnostic stability, whereas OCD and "other" anxiety disorders showed the lowest diagnostic stability. No significant sex differences were observed on the diagnostic stability of the anxiety disorder categories studied. Diagnostic stability measures for phobic, social anxiety, and "other" anxiety disorder diagnoses varied depending on the age at first evaluation. In this clinical pediatric outpatient sample it appears that phobic, social anxiety, and stress-related disorder diagnoses in children and adolescents treated in community outpatient services may have high diagnostic stability
Vibrational Relaxation and Redistribution Dynamics in Ruthenium(II) Polypyridyl-Based Charge-Transfer Excited States: A Combined Ultrafast Electronic and Infrared Absorption Study
Ultrafast time-resolved
electronic and infrared absorption measurements
have been carried out on a series of RuÂ(II) polypyridyl complexes
in an effort to delineate the dynamics of vibrational relaxation in
this class of charge transfer chromophores. Time-dependent density
functional theory calculations performed on compounds of the form
[RuÂ(CN-Me-bpy)x(bpy)3‑x]2+ (x = 1–3 for compounds 1–3, respectively, where CN-Me-bpy is
4,4′-dicyano-5,5′-dimethyl-2,2′-bipyridine and
bpy is 2,2′-bipyridine) reveal features in their charge-transfer
absorption envelopes that allow for selective excitation of the RuÂ(II)–(CN-Me-bpy)
moiety, the lowest-energy MLCT state(s) in each compound of the series.
Changes in band shape and amplitude of the time-resolved differential
electronic absorption data are ascribed to vibrational cooling in
the CN-Me-bpy-localized 3MLCT state with a time constant
of 8 ± 3 ps in all three compounds. This conclusion was corroborated
by picosecond time-resolved infrared absorption measurements; sharpening
of the CN stretch in the 3MLCT excited state was observed
with a time constant of 3.0 ± 1.5 ps in all three members of
the series. Electronic absorption data acquired at higher temporal
resolution revealed spectral modulation over the first 2 ps occurring
with a time constant of τ = 170 ± 50 fs, in compound 1; corresponding effects are significantly attenuated in compound 2 and virtually absent in compound 3. We assign
this feature to intramolecular vibrational redistribution (IVR) within
the 3MLCT state and represents a rare example of this process
being identified from time-resolved electronic absorption data for
this important class of chromophores
Morphological properties of slender Ca II H fibrils observed by SUNRISE II
We use seeing-free high spatial resolution Ca II H data obtained by the
SUNRISE observatory to determine properties of slender fibrils in the lower
solar chromosphere. In this work we use intensity images taken with the SUFI
instrument in the Ca II H line during the second scientific flight of the
SUNRISE observatory to identify and track elongated bright structures. After
the identification, we analyze theses structures in order to extract their
morphological properties. We identify 598 slender Ca II H fibrils (SCFs) with
an average width of around 180 km, a length between 500 km and 4000 km, an
average lifetime of ~400 s, and an average curvature of 0.002 arcsec^-1. The
maximum lifetime of the SCFs within our time series of 57 minutes is ~2000 s.
We discuss similarities and differences of the SCFs with other small-scale,
chromospheric structures such as spicules of type I and II, or Ca II K fibrils.Comment: Accepted for publication in The Astrophysical Journal Supplement
Serie
Effectiveness of the 23-valent polysaccharide pneumococcal vaccine against invasive pneumococcal disease in people 60 years or older
<p>Abstract</p> <p>Background</p> <p>The 23-valent polysaccharide pneumococcal vaccine (PPV) is currently recommended in elderly and high-risk adults. However, its efficacy in preventing pneumococcal infections remains controversial. This study assessed the clinical effectiveness of vaccination against invasive pneumococcal disease (IPD) among people over 60 years.</p> <p>Methods</p> <p>Population-based case-control study that included 88 case patients over 60 years-old with a laboratory-confirmed IPD (bacteraemic pneumonia, meningitis or sepsis) and 176 outpatient control subjects who were matched by primary care centre, age, sex and risk stratum. Adjusted odds ratios (ORs) for vaccination were calculated using conditional logistic regression, controlling for underlying conditions. Vaccine effectiveness was estimated as (1 - OR) Ă—100.</p> <p>Results</p> <p>Pneumococcal vaccination rate was significantly lower in cases than in control subjects (38.6% <it>vs </it>59.1%; p = 0.002). The adjusted vaccine effectiveness was 72% (OR: 0.28; 95% CI: 0.15-0.54) against all IPD and 77% (OR: 0.23; 95% CI: 0.08-0.60) against vaccine-type IPD. Vaccination was significantly effective against all IPD in both age groups: 60-79 years-old (OR 0.32; 95% CI: 0.14-0.74) and people 80 years or older (OR: 0.29; 95% CI: 0.09-0.91). Vaccination appears significantly effective as for high-risk immunocompetent subjects (OR: 0.29; 95% CI: 0.11-0.79) as well as for immunocompromised subjects (OR: 0.12; 95% CI: 0.03-0.53).</p> <p>Conclusion</p> <p>These findings confirm the effectiveness of the 23-valent PPV against IPD, and they also support the benefit of vaccination in preventing invasive infections among high-risk and older people.</p
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