Performance and carcass traits of progeny of Limousin sires differing in genetic merit

peer-reviewedGenetic indices for growth and carcass classification are published for beef sires used in Ireland for artificial insemination (AI). The objective of this study was to compare growth and carcass traits of progeny of Limousin sires of low and high genetic index for growth. A total of 70 progeny (42 males and 28 females) out of predominantly Holstein-Friesian cows by 7 AI Limousin sires were reared together to slaughter. The 7 sires were classified as low (n=3) or high (n=4) index based on their published genetic index for growth. The male progeny were reared entire and all animals were slaughtered at about 20 months of age. Carcasses were classified for conformation and fatness, and a rib joint (ribs 6 to 10) was separated into fat, muscle and bone. Growth rate did not differ significantly between the index groups but tended to be higher for the high index progeny. This higher growth rate, combined with a significantly higher kill out proportion, resulted in carcass weight andcarcass weight per day of age being significantly higher for the high index progeny. Carcass conformation and fat class were not affected by genetic index, nor was the composition of the rib joint. Compared with males, females had a significantly lower growth rate and kill out proportion and, consequently, had a significantly lower carcass weight. The proportions of fat and bone in the rib joint were significantly higher, and the proportion of muscle was significantly lower for females than for males. It is concluded that carcass weight reflected sire group genetic index for growth but feed intake, carcass classification and rib joint composition were not affected

Axion Decay in a Constant Electromagnetic Background Field and at Finite Temperature using World-line Methods

We investigate the radiative decay of the axion into two photons in an external electromagnetic field to one loop order. Our approach is based on the world-line formalism, which is very suitable to take into account the external field to all orders. Afterwards we discuss how the calculation could be generalized to finite temperature.Comment: 27 pages, 4 figures, corrected and added some references and added some remarks to appendix

On K\"ahler conformal compactifications of U(n)U(n)-invariant ALE spaces

We prove that a certain class of ALE spaces always has a Kahler conformal compactification, and moreover provide explicit formulas for the conformal factor and the Kahler potential of said compactification. We then apply this to give a new and simple construction of the canonical Bochner-K\"ahler metric on certain weighted projective spaces, and also to explicitly construct a family Kahler edge-cone metrics on $\mathbb{CP}^2$, with singular set $\mathbb{CP}^1$, having cone angles $2\pi\beta$ for all $\beta>0$. We conclude by discussing how these results can be used to obtain certain well-known Einstein metrics.Comment: 14 page

QCD and Hard Diffraction at the LHC

As an introduction to QCD at the LHC I give an overview of QCD at the Tevatron, emphasizing the high Q^2 frontier which will be taken over by the LHC. After describing briefly the LHC detectors I discuss high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. I introduce the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.Comment: To be published in Proceedings of the XIth International Conference on Elastic and Diffractive Scattering, BLois (2005). 6 pages, 0 figure

Fuzzy Logic Path Planning System for Collision Avoidance by an Autonomous Rover Vehicle

Systems already developed at JSC have shown the benefits of applying fuzzy logic control theory to space related operations. Four major issues are addressed that are associated with developing an autonomous collision avoidance subsystem within a path planning system designed for application in a remote, hostile environment that does not lend itself well to remote manipulation of the vehicle involved through Earth-based telecommunication. A good focus for this is unmanned exploration of the surface of Mars. The uncertainties involved indicate that robust approaches such as fuzzy logic control are particularly appropriate. The four major issues addressed are: (1) avoidance of a single fuzzy moving obstacle; (2) back off from a dead end in a static obstacle environment; (3) fusion of sensor data to detect obstacles; and (4) options for adaptive learning in a path planning system