28 research outputs found
Analyzing the Longevity of Sperm Within the Female Japanese Quail by Assessing Sperm Penetration of the Perivitelline Layer Under Optimal and Suboptimal Conditions.
After mating, birds have the ability to store semen within the female reproductive tract. The sperm storage tubules will store and subsequently release semen to travel up the oviduct. Sperm cells that make the trek up the oviduct have a chance to fertilize the ovum. These sperm cells will bind to the perivitelline layer of the ovum and hydrolyze a hole in the perivitelline layer, where it has the possibility to fertilize the female sex cell. Analyzing the number of penetration points on the perivitelline layer is an effective way to analyze reproductive efficiency. Many environmental factor has its effect on reproductive efficiency, however, only a few research trials have been done that analyze how environmental variables affect sperm penetration in itself. A population of 120 twelve week old random bred Japanese coturnix quail was separated into breeding ratios of three hens per cock making 30 pens with four birds in each. Treatments of optimal nutrition, suboptimal nutrition, and mild heat stress 75-80°F were utilized. These treatments were compared to a control group, where the males were not removed from the pen after 14 days. Males were left in the breeding pens for 14 days and then taken out, except for the control group where the males resided for the entire duration of the study. Sperm penetration assays were taken and analyzed every other day until no fertile eggs were laid. On every other consecutive day, eggs were collected and set to incubate until hatch. After hatch, percent hatchability was calculated. It was observed according to
Davisâ Correlation coefficients that day of the trial has a substantial negative correlation on sperm penetration and percent hatch by (-0.65871) and (-0.5058) respectfully. Sperm penetration and percent hatch show a very strong positive correlation of (0.76404). This population of quail was observed to store semen in sufficient quantities to maintain at »30 sperm penetration points (SPP) for 3 days before dropping significantly in SPP (p \u3c 0.0001). Where this same population could lay hatchable eggs for 8 days before dropping in hatching percentage, (P \u3c 0.0024). Additionally, it was observed that proper nutrition had a more significantly greater effect by increasing SPP and slightly increasing percent hatch than the effects of heat stress. Overall, it appears that similar trials that observe the longevity of fertility could be used to model the environmental effects on SPP, transversely affecting hatchability
Implementing a Mandatory Physical Fitness Program for All Sworn Police Personnel
Recommends mandatory physical fitness programs for all officers. Examines in context of the well being of the officers, medical care costs, liability and early retirement
Submarine channel network evolution above an extensive mass-transport complex: A 3D seismic case study from the Niger delta continental slope
A submarine channel network, named Abalama Channel System (ACS), has been recognised in the subsurface of the Niger Delta continental slope. It overlies a mass-transport complex (MTC) and consists of six channel segments, delimited by five avulsion points and one confluence point. High-resolution 3D seismic data are used to investigate the development of the ACS and to describe the interaction between the channels and the underlying MTC. The MTC mainly consists of highly disaggregated materials (MTC matrixes) and in plan-view has a very complex fingered geometry, characterised by the presence of erosional remnants (remnant blocks). The different character of the MTC matrixes compared to that of the remnant blocks likely resulted in a bathymetry characterised by negative and positive relief, which provided the initial confinement for the channels of the ACS. In areas where the MTC-induced confinement was weak or decreased abruptly, channels tended to develop higher sinuosity, increasing channels instability and ultimately causing avulsions. Three ideal categories of submarine channel avulsions are observed. Type 1 is characterised by parent and avulsion channel having similar size and maturity; Type 2 is characterised by a large, high-maturity parent channel and a small, low-maturity avulsion channel; Type 3 emphasizes the larger scale and higher maturity of the avulsion channel compared to the parent channel. In the distal part of the study area, topography related to mud diapirs provided lateral confinement that captured flows avulsed at different times resulting in a channel confluence phenomenon. Submarine channel network evolution recorded by avulsion and confluence points represents an important research theme in deep-water sedimentology, as it controls the final distribution of sediments and the extension of sands in the whole deep-water depositional system; hence this study can be used to guide hydrocarbon exploration in analogue systems
Submarine mass failures as tsunami sources : their climate control
Recent research on submarine mass failures (SMFs) shows that they are a source of hazardous tsunamis, with the tsunami magnitude mainly dependent on water depth of failure, SMF volume and failure mechanism, cohesive slump or fragmental landslide. A major control on the mechanism of SMFs is the sediment type, together with its post-depositional alteration. The type of sediment, fine- or coarse-grained, its rate of deposition together with post-depositional processes may all be influenced by climate. Post-depositional processes, termed sediment âpreconditioningâ, are known to promote instability and failure. Climate may also control the triggering of SMFs, for example through earthquake loading or cyclic loading from storm waves or tides. Instantaneous triggering by other mechanisms such as fluid overpressuring and hydrate instability is controversial, but is here considered unlikely. However, these mechanisms are known to promote sediment instability. SMFs occur in numerous environments, including the open continental shelf, submarine canyon/fan systems, fjords, active river deltas and convergent margins. In all these environments there is a latitudinal variation in the scale of SMFs. The database is limited, but the greatest climate influence appears to be in high latitudes where glacial/interglacial cyclicity has considerable control on sedimentation, preconditioning and triggering. Consideration of the different types of SMFs in the context of their climate controls provides additional insight into their potential hazard in sourcing tsunamis. For example, in the Atlantic, where SMFs are common, the tsunami hazard under the present-day climate may not be as great as their common occurrence suggests