Non-perturbative bottom PDF and its possible impact on new physics searches

Heavy quark parton distribution functions (PDFs) play an important role in several Standard Model and New Physics processes. Most PDF analyses rely on the assumption that the charm and bottom PDFs are generated perturbatively by gluon splitting and do not include any non-perturbative degrees of freedom. However, a non-perturbative, intrinsic heavy quark PDFs have been predicted in the literature. We demonstrate that to a very good approximation the scale-evolution of the intrinsic heavy quark content of the nucleon is governed by non-singlet evolution equations, and use this approximation to model the intrinsic bottom distribution and its impact on parton-parton luminosities at the LHC.Comment: Presented at the Cracow Epiphany Conference, 7-9 January 2016, Krakow, Polan

A survey on goat production in a semi-arid smallholder farming area situated in the north of Zimbabwe

An appraisal of goat production in a small-holder rural farming area of Zimbabwe.A survey was carried out to evaluate goat production in a crop-livestock farming area in the north of Zimbabwe. The objectives of the study were to determine goat production systems and productivity. Qualitative information was obtained using participatory rural appraisal techniques (PRA) while quantitative data was obtained through administration of a structured questionnaire to 317 households. The major finding of the survey indicated that the predominant goat breed found was the “small” indigenous Mashona goat. The goats were reared exclusively through extensive foraging during the dry season but were herded, tethered or a combination was used during the cropping season. Flock sizes were small, averaging 12 goats/household resulting in few goats available for sale or slaughter. All goat sales were informal. Ninety one percent of farmers indicated interest in cross breeding Mashona does with Boer bucks to improve the size of the Mashona

Transverse momentum dependent splitting functions at work: quark-to-gluon splitting

Using the recently obtained Pgq splitting function we extend the low x evolution equation for gluons to account for contributions originating from quark-to-gluon splitting. In order to write down a consistent equation we resum virtual corrections coming from the gluon channel and demonstrate that this implies a suitable regularization of the Pgq singularity, corresponding to a soft emitted quark. We also note that the obtained equation is in a straightforward manner generalized to a nonlinear evolution equation which takes into account effects due to the presence of high gluon densities.Comment: 13 pages, 3 figures, published versio

Incidence of bruising and dark firm dry beef in cattle carcasses in a commercial abattoir in Zimbabwe: an animal welfare concern

A reseach paper on the beef industry in Zimbabwe.The incidence of carcass bruising and occurrence of dark, firm, dry (DFD) beef in slaughter cattle were investigated from a survey of 9585 cattle delivered to a commercial abattoir. The objectives of the study were to evaluate the extent of occurrence of carcass bruising and DFD in slaughter cattle as these have a major impact on economic returns to the beef producer. In addition, these data can be used as indicators of either good or poor welfare of the animals prior to slaughter. In this study, the overall incidence of bruising was 29.6 percent while that of DFD was 27.4 percent. There were differences between the incidences of both bruising and DFD (p<0.001) in carcasses from bulls, steers and cows. Overall, bulls had the greatest carcass damage and steers the lowest. In addition, bruising increased (r = 0.97; p<0.05) and the incidence of DFD also increased (r = 0.94; p<0.05) with increasing transit distance. Linear regression analysis showed that a sixty kilometer increase in transit distance resulted in a seven percent increment in bruising (equation: y = 6.9 + 7.1 x; R2 = 0.96; p = 0.0047). However, there was no association between bruising and DFD. Among different carcass weights, there was considerable variation in frequency of occurrence of DFD (p<0.001), with the proportion of carcasses showing DFD decreasing as carcass weight increased. The results indicate substantial compromised animal welfare and major economic loss to the entire livestock industry. Further, the results suggest that transit distance appears to contribute substantially to causes of bruising and DFD in slaughter cattle in Zimbabwe

On the dependence of QCD splitting functions on the choice of the evolution variable

We show that already at the NLO level the DGLAP evolution kernel Pqq starts to depend on the choice of the evolution variable. We give an explicit example of such a variable, namely the maximum of transverse momenta of emitted partons and we identify a class of evolution variables that leave the NLO Pqq kernel unchanged with respect to the known standard MS-bar results. The kernels are calculated using a modified Curci-Furmanski-Petronzio method which is based on a direct Feynman-graphs calculation.Comment: 16 pages, 4 figure