701 research outputs found
Probing the Perturbative NLO Parton Evolution in the Small- Region
A dedicated test of the perturbative QCD NLO parton evolution in the very
small- region is performed. We find a good agreement with recent precision
HERA-data for , as well as with the present determination of the
curvature of . Characteristically, perturbative QCD evolutions result in
a positive curvature which increases as decreases. Future precision
measurements in the very small -region, , could provide a
sensitive test of the range of validity of perturbative QCDComment: Revised version, to appear in EPJ
Resumos...
Editado por: César Luís Girardi, Carlos Alberto Ely Machado, Henrique Pessoa dos Santos, Luís Fernando Revers, Marcos Botton e Mauro Celso Zanus
Neutrinos in a vacuum dominated cosmology
We explore the dynamics of neutrinos in a vacuum dominated cosmology. First
we show that such a geometry will induce a phase change in the eigenstates of a
massive neutrino and we calculate the phase change. We also calculate the delay
in the neutrino flight times in this geometry. Applying our results to the
presently observed background vacuum energy density, we find that for neutrino
sources further than away both effects become non-trivial, being of
the order of the standard relativistic corrections. Such sources are within the
obsevable Hubble Deep Field. The results which are theoretically interesting
are also potentially useful, in the future, as detection techniques improve.
For example such effects on neutrinos from distant sources like supernovae
could be used, in an independent method alternative to standard candles, to
constrain the dark energy density and the deceleration parameter. The
discussion is extended to investigate Caianiello's inertial or maximal
acceleration (MA) effects of such a vacuum dominated spacetime on neutrino
oscillations. Assuming that the MA phenomenon exists, we find that its form as
generated by the presently observed vacuum energy density would still have
little or no measurable effect on neutrino phase evolution.Comment: 10 pages, LaTeX, no figure
Resumos...
Editado por César Luís Girardi, Henrique Pessoa dos Santos, Lucimara Rogéria Antoniolli, Luis Fernando Revers, Marcos Botton e Sandra de Souza Sebben
Associações biológicas entre espécies florestais e microorganismos para o aumento da produtividade econômica dos reflorestamentos: anais.
bitstream/item/162758/1/Doc-12.pd
Prevention of conversion to abnormal tcd with hydroxyurea in sickle cell anemia: A phase III international randomized clinical trial
Children with sickle cell anemia (SCA) and conditional transcranial Doppler (TCD) ultrasound velocities (170-199 cm/sec) may develop stroke. However, with limited available clinical data, the current standard of care for conditional TCD velocities is observation. The efficacy of hydroxyurea in preventing conversion from conditional to abnormal TCD (\u3e/=200 cm/sec), which confers a higher stroke risk, has not been studied prospectively in a randomized trial. Sparing Conversion to Abnormal TCD Elevation (SCATE #NCT01531387) was an NHLBI-funded Phase III multicenter international clinical trial comparing alternative therapy (hydroxyurea) to standard care (observation) to prevent conversion from conditional to abnormal TCD velocity in children with SCA. SCATE enrolled 38 children from the United States, Jamaica, and Brazil [HbSS (36), HbSbeta0 -thalassemia (1), and HbSD (1), median age 5.4 years (range, 2.7-9.8)]. Due to slow patient accrual and administrative delays, SCATE was terminated early. In an intention-to-treat analysis, the cumulative incidence of abnormal conversion was 9% (95% CI 0 to 35%) in the hydroxyurea arm and 47% (95% CI 6 to 81%) in observation arm at 15 months (p=0.16). In post-hoc analysis according to treatment received, significantly fewer children on hydroxyurea converted to abnormal TCD velocities, compared to observation (0% versus 50%, p=0.02). After a mean of 10.1 months, a significant change in mean TCD velocity was observed with hydroxyurea treatment (-15.5 versus +10.2 cm/sec, p=0.02). No stroke events occurred in either arm. Hydroxyurea reduces TCD velocities in children with SCA and conditional velocities. This article is protected by copyright. All rights reserved
Anais...
A bioeconomia e a agricultura sustentável são temas de relevância global, com impactos diretos na mitigação das mudanças climáticas, na segurança alimentar e na transição para uma economia circular. A produção de biomassa como fonte renovável de energia e matéria-prima para múltiplas indústrias desempenha um papel fundamental na redução das emissões de carbono e na transição para uma economia limpa e de base renovável. É com base nesse contexto que a Embrapa Agroenergia propõe a realização do VII Encontro de Pesquisa e Inovação abordando o tema: ?Bioeconomia e Agricultura: Vetores de Descarbonização e Circularidade na Indústria?, com o objetivo de promover o debate, a troca de conhecimentos e o estabelecimento de parcerias estratégicas entre setores vitais para o desenvolvimento sustentável.Editoras Técnicas: Raquel Bombarda Campanha; Lorena Costa Garcia Calsing
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