Model-independent extraction of ∣Vtq∣|V_{tq}| matrix elements from top-quark measurements at hadron colliders

Current methods to extract the quark-mixing matrix element $|V_{tb}|$ from single-top production measurements assume that $|V_{tb}|\gg |V_{td}|, |V_{ts}|$: top quarks decay into $b$ quarks with 100% branching fraction, s-channel single-top production is always accompanied by a $b$ quark and initial-state contributions from $d$ and $s$ quarks in the $t$-channel production of single top quarks are neglected. Triggered by a recent measurement of the ratio $R=\frac{|V_{tb}|^{2}}{|V_{td}|^{2}+|V_{ts}|^{2}+|V_{tb}|^{2}}=0.90 \pm 0.04$ performed by the D0 collaboration, we consider a $|V_{tb}|$ extraction method that takes into account non zero d- and s-quark contributions both in production and decay. We propose a strategy that allows to extract consistently and in a model-independent way the quark mixing matrix elements $|V_{td}|$, $|V_{ts}|$, and $|V_{tb}|$ from the measurement of $R$ and from single-top measured event yields. As an illustration, we apply our method to the Tevatron data using a CDF analysis of the measured single-top event yield with two jets in the final state one of which is identified as a $b$-quark jet. We constrain the $|V_{tq}|$ matrix elements within a four-generation scenario by combining the results with those obtained from direct measurements in flavor physics and determine the preferred range for the top-quark decay width within different scenarios.Comment: 36 pages, 17 figure

Effects of Storage and Exogenous Ga3 on Lychee Seed Germination

The effects of storage time and exogenous gibberellic acid on lychee seeds germination were studied. The seeds were removed from ripe fruits, washed, dried, stored at 8°C for 0, 15 and 30 days, and soaked during 24 hours in water and GA3 at 50, 100 and 200 mg.L-1 solutions. As the storage period increased, the germination capacity was lost, and the seeds had a short germinability after 30-day storage period. Gibberellic acid had not significant effect on enhancing both the germination percentage and rate.<br>O trabalho teve como objetivo estudar os efeitos do tempo de armazenamento e de tratamentos com ácido giberélico, no processo germinativo de sementes de lichieira (Litchi chinensis Sonn.). As sementes foram retiradas de frutos maduros, lavadas, secas à sombra e colocadas para germinar imediatamente ou então, armazenadas em geladeira (8°C) por 15 e 30 dias. Os tratamentos corresponderam à imersão das sementes por 24 horas nas seguintes soluções com aeração: água, GA3 a 50, 100 e 200 mg.L-1. Através dos resultados obtidos, observou-se que as sementes perderam o poder germinativo, à medida que aumentou-se o tempo de armazenamento, sendo a porcentagem de germinação muito baixa (7%) aos 30 dias de armazenamento. O tempo médio de germinação foi menor após 15 dias de armazenamento

Pharmacokinetics and synovial fluid concentrations of flurbiprofen enantiomers in horses: chiral inversion

Flurbirpofen (FBP), a member of the 2-aryl propionate nonsteroidal anti-inflammatory drug class, has potent anti-inflammatory and analgesic properties. The commercial preparation is a racemic mixture of the R(−) and S(+) enantiomers of FBP. In this study, R(−) and S(+) FBP were used to investigate the metabolic chiral inversion. Each enantiomer was administered separately (0.25 mg/kg) and in a racemic mixture (0.5 mg/kg) intravenously to horses. Plasma and synovial concentration of each enantiomer was determined and the disposition of each was analyzed. After intravenous administration of R(−) FBP and S(+) FBP to horses no chiral inversion was detected. After the administration of the FBP racemate and individual enantiomers no differences were observed between pharmacokinetic parameters [t1/2â (h), Cl (L/h·kg), AUC (ìg·h/mL), Vss (L/kg) and MRT (h)] for R(−) and S(+) FBF. Synovial fluid concentrations of both FBP enantiomers were lower than plasma concentrations and no stereoselective differences were detected. These data indicate that the disposition of FBF in horses is not enantioselective and demonstrate a difference in the pharmacokinetic behavior of the enantiomers as compared with other 2-aryl-propionic acids, such as carprofen, ketoprofen and vedaprofen in the horse.Fil: Soraci, Alejandro Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencia Veterinarias. Departamento de Fisiopatología. Laboratorio de Toxicología; ArgentinaFil: Tapia, Maria Ofelia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencia Veterinarias. Departamento de Fisiopatología. Laboratorio de Toxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia, Jorge. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencia Veterinarias. Departamento de Fisiopatología. Laboratorio de Toxicología; Argentin