18 research outputs found

    Observation of the B_c Meson in p-bar p Collisions at sqrt{s} = 1.8 TeV

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    We have observed bottom-charm mesons B_c via the decay mode Bc -> J/psi lepton neutrino in 1.8 TeV p-bar p collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi + lepton mass distribution yielded 20.4 +6.2 -5.5 events from B_c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B_c mass to be 6.40 +- 0.39 +- 0.13 GeVc^2 and the B_c lifetime to be tau(B_c) = 0.46 +0.18 -0.16 +- 0.03 ps. We measured the production cross section times branching ratio for B_c -> J/psi lepton neutrino relative to that for B+ -> J/psi K to be 0.132 +0.041 -0.037 (stat) +- 0.031 (syst) +0.032 -0.020 (lifetime).Comment: 13 pages, 3 figures. Submitted to Physical Review Letters. Available at http://www-cdf.fnal.gov/physics/pub98/cdf4496_Bc_PRL.p

    The behaviour and welfare of buffaloes (Bubalus bubalis) in modern dairy enterprises

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    This review deals with the behaviour of river buffaloes (Bubalus bubalis), in confinement and in extensive conditions, also focusing on the effects of different housing and rearing conditions on their welfare. The behavioural repertoire expressed by buffaloes in extensive and intensive conditions is similar to those displayed by other domestic ruminants. However, through natural selection, buffaloes have also acquired several morphological, physiological and behavioural (i.e. wallowing) adaptations to hot climatic conditions. Buffaloes kept in intensive conditions and having no access to pasture and water for wallowing extend their periods of idling and are less often involved in investigative activities. Confinement is also associated with a reduction of space; however, no specific studies have been carried out to determine the specific requirements of this species. Space restriction can adversely affect various aspects of buffalo welfare, such as health (increased levels of lesions and injuries), social behaviour (increased number of agonistic interactions) and heat dissipation. The buffaloes, originating from tropical areas, are well adapted to large variations in food availability and quality, and to dietetic unbalances. As to human animal relationship, it has been observed that the incidence of stepping and kicking behaviour of buffaloes in the milking parlour is positively correlated with the frequency of oxytocin injections, whereas the frequency of positive stockperson interactions with the animals such as talking quietly, petting and gentle touching are negatively correlated with the number of kicks during milking. Data from farms where both dairy cattle and buffaloes are present show that avoidance distance measured in the pen is lower in buffaloes than in cattle. This may be attributed to the fact that buffaloes are generally recognised to be curious animals. Finally, the effects of different farming practices on animal-related indicators are described. However, these measures should be integrated into a monitoring protocol, such as the Welfare QualityR scheme, to reliably assess buffalo welfare in the current intensive farming conditions
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