1,376 research outputs found
Blackwell-Optimal Strategies in Priority Mean-Payoff Games
We examine perfect information stochastic mean-payoff games - a class of
games containing as special sub-classes the usual mean-payoff games and parity
games. We show that deterministic memoryless strategies that are optimal for
discounted games with state-dependent discount factors close to 1 are optimal
for priority mean-payoff games establishing a strong link between these two
classes
Colite pseudomembranosa : uma casuĂstica de internamentos
Introduction: pseudomembranous colitis (PMC) is an infectious disease that generally begins after antibiotic treatment.
Objectives: Characterize the patients with PMC in two Services of a Central Hospital.
Material and Methods: we considered the patients admitted in a Medicine (MS) and in a Gastroenterology (GES) Service with primary or secondary diagnosis of PMC, between January/1995 and July/2003 and registered the age, gender, clinical presentation, antibiotics (AB) and other risk factors, diagnostic procedures, complications and treatment.
Results: we considered 80 patients (43 - GES and 37 - MS); Mean age - 68,6 ± 17,7 years; 52,5% were male; Antibiotic treatment in the previous 3 months - 85%; Mean time of antibiotic treatment - 10,5 ± 6,1 days. Most Commonly Involved Antibiotics: cephalosporins, amoxicillin/clavulanic acid and quinolones. Associated risk factors: renal insufficiency (22,5%); cardiac insufficiency (22,5%); previously dependent patient ( 36,3%).
Diagnostic procedures: toxin search-58 patients ( in 36 ), colonoscopy - 62 ( in 53); culture - 23 (in 17 ). The mortality rate was 18,8% (n = 15); recurrence rate - 10% (n = 8).
Therapeutics: metronidazol - 37 patients (46,3%); vancomycin - 24 (30%); metronidazol + vancomycin – 12 (15%).
Differences Between Services: mean age (MS - 72,9 and GES - 64,9); admission criteria (GES - intestinal disorders, MS – respiratory infections); diagnostic procedures (colonoscopy more frequent in GES); therapeutic options (MS - metronidazol; GES - vancomycin and metronidazol + vancomycin).
Conclusions: PMC is more common in older patients that were generally submitted to previous antibiotic treatment, especially with Ăź-lactamics. Considering two distinct Services we observed differences concerning age, co-morbility and risk factors that implied distinct diagnostic and therapeutic approaches
Neutrino Detection with Inclined Air Showers
The possibilities of detecting high energy neutrinos through inclined showers
produced in the atmosphere are addressed with an emphasis on the detection of
air showers by arrays of particle detectors. Rates of inclined showers produced
by both down-going neutrino interactions and by up-coming decays from
earth-skimming neutrinos as a function of shower energy are calculated with
analytical methods using two sample neutrino fluxes with different spectral
indices. The relative contributions from different flavors and charged, neutral
current and resonant interactions are compared for down-going neutrinos
interacting in the atmosphere. No detailed description of detectors is
attempted but rough energy thresholds are implemented to establish the ranges
of energies which are more suitable for neutrino detection through inclined
showers. Down-going and up-coming rates are compared.Comment: Submitted to New Journal of Physic
Indicadores de digestibilidade de dietas para ovinos contendo feno de ponta de cana-de-açúcar hidrolisado.
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Numerical calculation of the Casimir-Polder interaction between a graphene sheet with vacancies and an atom
In this work the Casimir-Polder interaction energy between a rubidium atom and a disordered graphene sheet is investigated beyond the Dirac cone approximation by means of accurate real-space tight-binding calculations. As a model of defected graphene, we consider a tight-binding model of π electrons on a honeycomb lattice with a small concentration of vacancies. The optical response of the graphene sheet is evaluated with full spectral resolution by means of exact Chebyshev polynomial expansions of the Kubo formula in large lattices in excess of 10 million atoms. At low temperatures, the optical response of defected graphene is found to display two qualitatively distinct behaviors with a clear transition around finite (nonzero) Fermi energy. In the vicinity of the Dirac point, the imaginary part of optical conductivity is negative for low frequencies while the real part is strongly suppressed. On the other hand, for high doping, it has the same features found in the Drude model within the Dirac cone approximation, namely, a Drude peak at small frequencies and a change of sign in the imaginary part above the interband threshold. These characteristics translate into a nonmonotonic behavior of the Casimir-Polder interaction energy with very small variation with doping in the vicinity of the neutrality point while having the same form of the interaction calculated with Drude's model at high electronic density
QED self-energy contribution to highly-excited atomic states
We present numerical values for the self-energy shifts predicted by QED
(Quantum Electrodynamics) for hydrogenlike ions (nuclear charge ) with an electron in an , 4 or 5 level with high angular momentum
(). Applications include predictions of precision transition
energies and studies of the outer-shell structure of atoms and ions.Comment: 20 pages, 5 figure
Hydrolyzed sugarcane tip hay constitutes alternative forage in diets for finishing sheep.
The balance of nitrogen compounds was evaluated in finishing sheep fed diets containing hydrolyzed sugarcane tip hay. The experiment was carried out at the DZO/CCA/UFPI, in Teresina, PI, Brazil
Small x behavior of the slope dlnF_2/dln(1/x) in the framework of perturbative QCD
Using an analytical parameterization for the behavior of the x slope of the
structure function F_2 at small x in perturbative QCD, at the leading twist
approximation of the Wilson operator product expansion, and applying a flat
initial condition in the DGLAP evolution equations, we found very good
agreement with new precise deep inelastic scattering experimental data from
HERA.Comment: 13 pages, 3 figures, late
QCD
We discuss issues of QCD at the LHC including parton distributions, Monte
Carlo event generators, the available next-to-leading order calculations,
resummation, photon production, small x physics, double parton scattering, and
backgrounds to Higgs production.Comment: 115 pages, Latex, 47 figures, to appear in the Report of the ``1999
CERN Workshop on SM Physics (and more) at the LHC'', S. Catani, M. Dittmar,
D. Soper, W.J. Stirling, S. Tapprogge (convenors
Small x behavior of parton distributions. A study of higher twist effects
Higher twist corrections to the structure function F_2 at small x are studied
for the case of a flat initial condition for the twist-two QCD evolution in the
next-to-leading order approximation. We present an analytical parameterization
of the contributions from the twist-two and higher twist operators of the
Wilson operator product expansion. Higher twist terms are evaluated using two
different approaches, one motivated by BFKL and the other motivated by the
renormalon formalism. The results of the latter approach are in very good
agreement with deep inelastic scattering data from HERA.Comment: 46 pages, 9 figures, typeset using REVTeX. Misprints corrected, new
results, discussions, references and acknowledgements added, 2 pictures
replaced. The conclusions remain unchange
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