925 research outputs found
Cystic fibrosis – Comparison between patients in paediatric and adult age
AbstractCystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians. Although most cases are diagnosed in childhood, diagnosis in adults is apparently increasing.ObjectiveEvaluate the adult population with CF, comparing patients who were diagnosed before and after 18 years of age.MethodsRetrospective analysis of patients followed in three main medical centres in Portugal in 2012. Comparison of two groups: G1 – patients diagnosed at <18 years and G2 – patients diagnosed at ≥18 years.Results89 adults were identified: 61.8% in G1, 38.2% in G2. Gender distribution was similar in both groups. Average age in G2 was higher (38.3±8.4 vs. 26.8±6.1 years, p<0.001). Respiratory symptoms most frequently led to CF diagnosis in all patients, mainly in adulthood. There was a greater percentage of patients homozygous for the mutation delF508 in G1 (43.6 vs. 8.8%, p=0.02). Respiratory and pancreatic function, and body mass index (BMI) showed a higher severity in G1 (G1 vs. G2: FEV1: 54.6±27.3 vs. 29.9±64.6%, p=0.177; pancreatic insufficiency 72.7 vs. 26.5%, p<0.001; BMI 20.2±3.4 vs. 22.2±4.8, p=0.018). Pseudomonas aeruginosa and methicillin-sensitive Staphylococcus aureus were the most frequently isolated microorganisms. Lung transplantation rate was higher in G2 (20.6 vs. 10.9%, p=0.231) while mortality rate was higher in G1 (0 vs. 3.6%, p=0.261). Hospital admission rate was higher in G1 as well as mortality rate.ConclusionThe results suggest that patients with CF diagnosed in childhood have characteristics that distinguish them from those diagnosed in adulthood, and these differences may have implications for diagnosis, prognosis and life expectancy
Exploring the high-temperature electrical performance of Ca3-xLaxCo4O9 thermoelectric ceramics for moderate and low substitution levels
Aliovalent substitutions in Ca3Co4O9 often result in complex effects on the electrical properties and the solubility, and impact of the substituting cation also depends largely on the preparation and processing method. It is also well-known that the monoclinic symmetry of this material’s composite crystal structure allows for a significant hole transfer from the rock salt-type Ca2CoO3 buffer layers to the hexagonal CoO2 ones, increasing the concentration of holes and breaking the electron-hole symmetry from the latter layers. This work explored the relevant effects of relatively low La-for-Ca substitutions, for samples prepared and processed through a conventional ceramic route, chosen for its simplicity. The obtained results show that the actual substitution level does not exceed 0.03 (x < 0.03) in Ca3-xLaxCo4O9 samples with x = 0.01, 0.03, 0.05 and 0.07 and that further introduction of lanthanum results in simultaneous Ca3Co4O9 phase decomposition and secondary Ca3Co2O6 and (La, Ca)CoO3 phase formation. The microstructural effects promoted by this phase evolution have a moderate influence on the electronic transport. The electrical measurements and determined average oxidation state of cobalt at room temperature suggest that the present La substitutions might only have a minor effect on the concentration of charge carriers and/or their mobility. The electrical resistivity values of the Ca3-xLaxCo4O9 samples with x = 0.01, 0.03 and 0.05 were found to be ~1.3 times (or 24%) lower (considering mean values) than those measured for the pristine Ca3Co4O9 samples, while the changes in Seebeck coefficient values were only moderate. The highest power factor value calculated for Ca2.99La0.01Co4O9 (~0.28 mW/K2m at 800 °C) is among the best found in the literature for similar materials. The obtained results suggest that low rare-earth substitutions in the rock salt-type layers can be a promising pathway in designing and improving these p-type thermoelectric oxides, provided by the strong interplay between the mobility of charge carriers and their concentration, capable of breaking the electron-hole symmetry from the conductive layers. © 2021 by the authors
Three-loop universal anomalous dimension of the Wilson operators in N=4 SUSY Yang-Mills model
We present results for the three-loop universal anomalous dimension of Wilson
twist-2 operators in the N=4 Supersymmetric Yang-Mills model. These results are
obtained by extracting the most complicated contributions from the three loop
non-singlet anomalous dimensions in QCD which were calculated recently. Their
singularities at j=1 agree with the predictions obtained from the BFKL equation
for N=4 SYM in the next-to-leading order. The asymptotics of universal
anomalous dimension at large j is in an agreement with the expectations based
on an interpolation between weak and strong coupling regimes in the framework
of the AdS/CFT correspondence.Comment: LaTeX file, 13 pages, no figures. Some corrections, additional
remarks and references. In the last version the analysis of anomalous
dimension at j -> 2 was improve
A model of the Universe including Dark Energy accounted for by both a Quintessence Field and a (negative) Cosmological Constant
In this work we present a model of the universe in which dark energy is
modelled explicitely with both a dynamical quintessence field and a
cosmological constant. Our results confirm the possibility of a future
collapsing universe (for a given region of the parameter space), which is
necessary for a consistent formulation of string theory and quantum field
theory. We have also reproduced the measurements of modulus distance from
supernovae with good accuracy.Comment: 11 pages, 4 figures, only the results for the single exponential
potential are preserved. One author added. Some changes in the reference
section. Submitted to Physical Review
DGLAP and BFKL evolution equations in the N=4 supersymmetric gauge theory
We derive the DGLAP and BFKL evolution equations in the N=4 supersymmetric
gauge theory in the next-to-leading approximation. The eigenvalue of the BFKL
kernel in this model turns out to be an analytic function of the conformal spin
|n|. Its analytic continuation to negative |n| in the leading logarithmic
approximation allows us to obtain residues of anomalous dimensions \gamma of
twist-2 operators in the non-physical points j=0,-1,... from the BFKL equation
in an agreement with their direct calculation from the DGLAP equation.
Moreover, in the multi-color limit of the N=4 model the BFKL and DGLAP dynamics
in the leading logarithmic approximation is integrable for an arbitrary number
of particles. In the next-to-leading approximation the holomorphic separability
of the Pomeron hamiltonian is violated, but the corresponding Bethe-Salpeter
kernel has the property of a hermitian separability. The main singularities of
anomalous dimensions \gamma at j=-r obtained from the BFKL and DGLAP equations
in the next-to-leading approximation coincide but our accuracy is not enough to
verify an agreement for residues of subleading poles.Comment: 45 pages, latex. In the last version the expression (16) for the
t-channel partial wave of the process e+e- --> \mu+\mu- in the
double-logarithmic approximation at QED is corrected and its derivation is
given in the Appendix
Partial Wave Analysis of the Reaction to Search for the "" Bound State
Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have
analyzed HADES data of the reaction . This
reaction might contain information about the kaonic cluster "" via its
decay into . Due to interference effects in our coherent description
of the data, a hypothetical (or, specifically "")
cluster signal must not necessarily show up as a pronounced feature (e.g. a
peak) in an invariant mass spectra like . Our PWA analysis includes a
variety of resonant and non-resonant intermediate states and delivers a good
description of our data (various angular distributions and two-hadron invariant
mass spectra) without a contribution of a cluster. At a
confidence level of CL=95\% such a cluster can not contribute more than
2-12\% to the total cross section with a final state, which
translates into a production cross-section between 0.7 and 4.2 ,
respectively. The range of the upper limit depends on the assumed cluster mass,
width and production process.Comment: 7 Pages, 5 Figure
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