RESUMEN
We discuss forward-backward charge asymmetries for lepton-pair production in association with a large-transverse-momentum jet at hadron colliders. The lepton charge asymmetry relative to the jet direction A(j)(FB) gives a new determination of the effective weak mixing angle sin((2)theta(lept)(eff)(M(2)(Z)) with a statistical precision after cuts of approximately 10(-3) (8x10(-3)) at LHC (Tevatron). This is to be compared with the current uncertainty at LEP and SLD from the asymmetries alone, 2x10(-4). The identification of b jets also allows for the measurement of the bottom-quark-Z asymmetry A(b)(FB) at hadron colliders, the resulting statistical precision for sin((2)theta(lept)(eff)(M(2)(Z)) being approximately 9x10(-4) (2x10(-2) at Tevatron), also lower than the reported precision at e(+)e(-) colliders, 3x10(-4).
RESUMEN
The distribution and time of appearance of 5HT-storing cells were studied in samples from the pancreas of mice embryos from 7 to 19 days of gestation. Additionally, 1- and 15-day-old newborns and adult specimens were also examined. Serotonin-immunoreactive cells appeared for the first time in the dorsal pancreatic primordium at 10 days of gestation and increased rapidly in number through E15. From this age, the cellular number diminished in the exocrine pancreatic parenchyma, although an increase of endocrine cells in Wirsung's duct can be detected. At day 15 of extrauterine life, we could only observe some cells in the surface epithelium of pancreatic duct of Wirsung. Islet immunoreactive cells could only be detected in adult animals.