Sperm precedence in the domestic fowl

The aim of this study was to examine last-male sperm precedence in the domestic fowl. We used sperm from two different genotypes to assign paternity: and in seven experiments females were artificially inseminated with either equal or unequal numbers of sperm at intervals of 4 or 24 h. We were unable to replicate the results of a previous study by Compton et al. (1978) in which a strong last-male precedence effect had been recorded when two equal sized inseminations were made 4 h apart. We observed no marked last-male sperm precedence and our results did not differ significantly from that predicted by the passive sperm loss model, in which a last-male effect is determined by the rate at which sperm are lost from the female tract and the interval between successive inseminations. The most likely explanation for the disparity between our result and Compton et al.'s is a difference in the timing of inseminations. The implications of this for studies of sperm competition in birds is discussed

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

The DUNE far detector vertical drift technology. Technical design report

DUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

Lipid and antioxidant composition of chicken semen and its susceptibility to peroxidation

The antioxidant composition of the chicken seminal plasma and spermatozoa and the effect of sperm storage on fatty acid composition of the phospholipid fraction were investigated. Chicken semen displayed ' range of antioxidants including vitamin E, ascorbic acid, glutathione , superoxide dismutase and glutathione peroxidase. Ascorbic acid was almost equally distributed between seminal plasma and spermatozoa. In contrast, reduced glutathione and vitamin E were located mainly in the spermatozoa. The main form of glutathione peroxidase (GSH-Px) was Se-dependent GSH-Px, which was found in both the seminal plasma and the spermatozoa. On the other hand, superoxide dismutase (SOD) was mainly located (67%) in the spermatozoa. Cu,Zn-SOD was found only in seminal plasma but both forms of the enzyme (Cu,Zn-SOD and Mn-SOD) were found in spermatozoa. The toxic effect of H 2O 2 and cumene hydroperoxide on sperm motility was determined. Sperm incubation for 12 hours at 20\ub0C was associated with a significant decrease in the proportion of 22:4n-6 in the phospholipid fraction. The inclusion of Fe 2+ in the incubation medium at 37\ub0C further increased the rate of lipid peroxidation as indicated by the significant decrease in the proportion of 20:4n-6, 22:4n-6, 22:5n-3 and 22:6n-3 in the phospholipid. Free radical-trapping activity of seminal plasma was measured. Possible mechanisms involved in sperm antioxidant protection are discussed

Fatty acid composition, glutathione peroxidase and superoxide dismutase activity and total antioxidant activity of avian semen

This work demonstrates that spermatozoa from five avian species (chicken, turkey, guinea fowl, duck and goose) are all characterised by high proportions of polyunsaturated fatty acids, from 46 (turkey) to 55% (duck) of total. For each of the species, the most abundant fatty acids were arachidonic (20:4n-6) and docosatetraenoic (22:4n-6) acids, representing between 22 (turkey) and 40% (chicken) of total. Significant activities of the major isozymes of superoxide dismutase and glutathione peroxidase, which protect against the peroxidation associated with high degree of fatty acid unsaturation, were found in spermatozoa from all species. The seminal plasma also had these activities and showed additional mechanisms for protecting spermatozoa from peroxidation. In general terms, these lipid and enzyme proteins were similar between the five avian species and different from those reported for mammalian sperm. Copyright (C) 1998 Elsevier Science Inc