694 research outputs found
Dynamical and stationary critical behavior of the Ising ferromagnet in a thermal gradient
In this paper we present and discuss results of Monte Carlo numerical
simulations of the two-dimensional Ising ferromagnet in contact with a heat
bath that intrinsically has a thermal gradient. The extremes of the magnet are
at temperatures , where is the Onsager critical temperature.
In this way one can observe a phase transition between an ordered phase
() by means of a single simulation. By
starting the simulations with fully disordered initial configurations with
magnetization corresponding to , which are then suddenly
annealed to a preset thermal gradient, we study the short-time critical dynamic
behavior of the system. Also, by setting a small initial magnetization ,
we study the critical initial increase of the order parameter. Furthermore, by
starting the simulations from fully ordered configurations, which correspond to
the ground state at T=0 and are subsequently quenched to a preset gradient, we
study the critical relaxation dynamics of the system. Additionally, we perform
stationary measurements () that are discussed in terms of
the standard finite-size scaling theory. We conclude that our numerical
simulation results of the Ising magnet in a thermal gradient, which are
rationalized in terms of both dynamic and standard scaling arguments, are fully
consistent with well established results obtained under equilibrium conditions
International comparability of reference unit costs of education services: when harmonizing methodology is not enough (PECUNIA project)
Background: Health problems can lead to costs in the education sector. However, these costs are rarely incorporated in health economic evaluations due to the lack of reference unit costs (RUCs), cost per unit of service, of education services and of validated methods to obtain them. In this study, a standardized unit cost calculation tool developed in the PECUNIA project, the PECUNIA RUC Template for services, was applied to calculate the RUCs of selected education services in five European countries. Methods: The RUCs of special education services and of educational therapy were calculated using the information collected via an exploratory gray literature search and contact with service providers. Results: The RUCs of special education services ranged from âŹ55 to âŹ189 per school day. The RUCs of educational therapy ranged from âŹ6 to âŹ25 per contact and from âŹ5 to âŹ35 per day. Variation was observed in the type of input data and measurement unit, among other. Discussion: The tool helped reduce variability in the RUCs related to costing methodology and gain insights into other aspects that contribute to the variability (e.g. data availability). Further research and efforts to generate high quality input data are required to reduce the variability of the RUCs
The Galactose Index measured in fibroblasts of GALT deficient patients distinguishes variant patients detected by newborn screening from patients with classical phenotypes
Background: The high variability in clinical outcome of patients with Classical Galactosemia (CG) is poorly understood and underlines the importance of prognostic biomarkers, which are currently lacking. The aim of this study was to investigate if residual galactose metabolism capacity is associated with clinical and biochemical outcomes in CG patients with varying geno- and phenotypes. Methods: Galactose Metabolite Profiling (GMP) was used to determine residual galactose metabolism in fibroblasts of CG patients. The association between the galactose index (GI) defined as the ratio of the measured metabolites [U13C]Gal-1-P/ [13C6]UDP-galactose, and both intellectual and neurological outcome and galactose-1-phosphate (Gal-1-P) levels was investigated. Results: GMP was performed in fibroblasts of 28 patients and 3 control subjects. The GI of the classical phenotype patients (n = 22) was significantly higher than the GI of four variant patients detected by newborn screening (NBS) (p = .002), two homozygous p.Ser135Leu patients (p = .022) and three controls (p = .006). In the classical phenotype patients, 13/18 (72%) had a poor intellectual outcome (IQ < 85) and 6/12 (50%) had a movement disorder. All the NBS detected variant patients (n = 4) had a normal intellectual outcome (IQ â„ 85) and none of them has a movement disorder. In the classical phenotype patients, there was no significant difference in GI between patients with a poor and normal clinical outcome. The NBS detected variant patients had significantly lower GI levels and thus higher residual galactose metabolism than patients with classical phenotypes. There was a clear correlation between Gal-1-P levels in erythrocytes and the GI (p = .001). Conclusions: The GI was able to distinguish CG patients with varying geno- and phenotypes and correlated with Gal-1-P. The data of the NBS detected variant patients demonstrated that a higher residual galactose metabolism may result in a more favourable clinical outcome. Further research is needed to enable individual prognostication and treatment in all CG patients
Vector meson production and nucleon resonance analysis in a coupled-channel approach for energies m_N < sqrt(s) < 2 GeV II: photon-induced results
We present a nucleon resonance analysis by simultaneously considering all
pion- and photon-induced experimental data on the final states gamma N, pi N, 2
pi N, eta N, K Lambda, K Sigma, and omega N for energies from the nucleon mass
up to sqrt(s) = 2 GeV. In this analysis we find strong evidence for the
resonances P_{31}(1750), P_{13}(1900), P_{33}(1920), and D_{13}(1950). The
omega N production mechanism is dominated by large P_{11}(1710) and
P_{13}(1900) contributions. In this second part we present the results on the
photoproduction reactions and the electromagnetic properties of the resonances.
The inclusion of all important final states up to sqrt(s) = 2 GeV allows for
estimates on the importance of the individual states for the GDH sum rule.Comment: 41 pages, 26 figures, discussion extended, typos corrected,
references updated, to appear in Phys. Rev.
Fractures, Bone Mineral Density, and Final Height in Craniopharyngioma Patients with a Follow-up of 16 Years
CONTEXT: Pituitary hormonal deficiencies in patients with craniopharyngioma may impair their bone health. OBJECTIVE: To investigate bone health in patients with craniopharyngioma. DESIGN: Retrospective cross-sectional study. SETTING: Dutch and Swedish referral centers. PATIENTS: Patients with craniopharyngioma (n = 177) with available data on bone health after a median follow-up of 16 years (range, 1-62) were included (106 [60%] Dutch, 93 [53%] male, 84 [48%] childhood-onset disease). MAIN OUTCOME MEASURES: Fractures, dual X-ray absorptiometry-derived bone mineral density (BMD), and final height were evaluated. Low BMD was defined as T- or Z-score â€-1 and very low BMD as â€-2.5 or â€-2.0, respectively. RESULTS: Fractures occurred in 31 patients (18%) and were more frequent in men than in women (26% vs. 8%, P = .002). Mean BMD was normal (Z-score total body 0.1 [range, -4.1 to 3.5]) but T- or Z-score â€-1 occurred in 47 (50%) patients and T-score â€-2.5 or Z-score â€-2.0 in 22 (24%) patients. Men received less often treatment for low BMD than women (7% vs. 18%, P = .02). Female sex (OR 0.3, P = .004) and surgery (odds ratio [OR], 0.2; P = .01) were both independent protective factors for fractures, whereas antiepileptic medication was a risk factor (OR, 3.6; P = .03), whereas T-score â€-2.5 or Z-score â€-2.0 was not (OR, 2.1; P = .21). Mean final height was normal and did not differ between men and women, or adulthood and childhood-onset patients. CONCLUSIONS: Men with craniopharyngioma are at higher risk than women for fractures. In patients with craniopharyngioma, a very low BMD (T-score â€-2.5 or Z-score â€-2.0) seems not to be a good predictor for fracture risk
The polycystic kidney disease 1 gene encodes a 14 kb transcript and lies within a duplicated region on chromosome 16
Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder that frequently results in renal fallure due to progressive cyst development. The major locus, PKD1, maps to 16p13.3. We identified a chromosome translocation associated with ADPKD that disrupts a gene (PBP) encoding a 14 kb transcript in the PKD1 candidate region. Further mutations of the PBP gene were found in PKD1 patients, two deletions (one a de novo event) and a splicing defect, confirming that PBP is the PKD1 gene. This gene is located adjacent to the TSC2 locus in a genomic region that is reiterated more proximally on 16p. The duplicate area encodes three transcripts substantially homologous to the PKD1 transcript. Partial sequence analysis of the PKD1 transcript shows that it encodes a novel protein whose function is at present unknown
P-wave excited baryons from pion- and photo-induced hyperon production
We report evidence for , , ,
, , and , and find
indications that might have a companion state at 1970\,MeV. The
controversial is not seen. The evidence is derived from a
study of data on pion- and photo-induced hyperon production, but other data are
included as well. Most of the resonances reported here were found in the
Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were
challenged recently by the Data Analysis Center at GWU. Our analysis is
constrained by the energy independent scattering amplitudes from either
KH84 or GWU. The two amplitudes from KH84 or GWU, respectively, lead to
slightly different branching ratios of contributing resonances but the
debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
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