Application Of Genetics

Animal breeding is an old art, which long ago developed far beyond the scientific knowledge of the subject. By actual experience men built up certain rules as to what practices were or were not good procedure for a given set of conditions. Man naturally devised philosophical. explanations which more or less satisfied his intellect as he went along. But it would be a far stretch of the imagination to call these explanations scientific

Linebreeding

Linebreeding is a form of inbreeding (usually mild) directed toward keeping the offspring closely related to one ancestor (usually a much admired one). All inbreeding not necessary for holding this relationship high is avoided as far as possible. It is practiced to conserve, among the descendants, the good traits of an outstanding sire or dam, increasing those descendants in numbers without lessening their resemblance to this ancestor even for many generations after that ancestor’s death. The more superior a breeder’s herd or flock is to the average merit of its breed, the more reason he has to practice linebreeding to his very best animals or to the very best of their recent ancestors. Breeders of grades cannot often afford to do much linebreeding

Out on First Record?

How accurately can one decide on the basis of a heifer\u27s first record whether she is good enough to keep

Genetic aspects of the Danish system of progeny-testing swine

1. The history of the Danish system of progeny testing swine is traced briefly. 2. Changes in the average characteristics of the Danish swine since this system began in 1907 are shown in graphs. 3. The variance of six of these characteristics is analyzed, largely by means of correlations between litter mates, between half-sibs and between progeny tests of sire and of son, to find the extent to which individual variance in each characteristic can be attributed to the additive effects of genes. 4. A little less than half the individual variance in body length, thickness of back fat and thickness of belly can be thus ascribed to additive gene effects. Differences in rate of gain, yield of export bacon and in economy of gain are less highly hereditary, yet there seems to be in them enough additive gene variance to permit selection still to make distinct changes in the population for at least a few more generations. (Summary in table 11.) 5. Although the actual basis of the selections which the Danish farmers practice is not completely demonstrated, the figures from these progeny tests must have played a considerable part. 6. The Danish plan of progeny testing has been developed in such close connection with the economic peculiarities of Danish cooperative organizations that its operating principles might need much revision before it could be used in other countries. The biological principles involved, however, are the same everywhere and any people wishing seriously to improve the real economic productivity of their livestock, especially in characteristics which cannot be seen or measured until the animals are slaughtered, will find useful suggestions in this Danish model

Application of Genetics to Animal Breeding - Paper Presented at the Fifty-Fifth Annual Meeting

Animal breeding is is an old art, which long ago developed far beyond the scientific knowledge of the subject. By actual experience men built up certain rules as to what practices were or were not good procedure for a given set of conditions. Man naturally devised philosophical explanations which more or less satisfied his intellect as he went along. But it would be a far stretch of the imagination to call those explanations scientific

Final Report: Two Dimensional Computer Simulation of Bilateral Silicon Solar Cells

Bilateral solar cells can convert albedo light (sunlight reflected from the earth) incident on the back side of the cell to improve the power to weight ratio of satellite arrays operating in Low Earth Orbits. However, the high energy radiation trapped in the Van Allen Belt surrounding the earth limits the possible improvement of solar cell electrical output by degrading the minority carrier diffusion length. The purpose of this work is to design cells to be able to collect efficiently albedo-generated carriers at end-of-life(EOL). The FORTRAN program Solar Cell Analysis Program in Two Dimensions is used to model four cell geometries for base resistivities of 1.0 to 1240. Ω—cm. The EOL efficiencies and normalized output power are compared for all cells. All the thicker (250. micron) cells modeled peak in performance within the 10.-40. Ω—cm base resistivity range both with and without albedo illumination. It is found that alternative geometries to the standard solar cell can be used to better collect albedo-generated carriers at EOL. The etched multiple vertical junction cell(22%) and the 50. micron thick standard cell(45%) show the most improvement in normalized output power over the best one- sun illuminated standard cell. Albedo light is modeled as 40. milliwatts /cm2 (AMI.5 spectrum), or 30% of one sun AM0.0 incident power. Values for the damage coefficient, Kj, are found in the literature for irradiation by 1.0 MeV electrons. Radiation induced degradation is modeled by SCAP2D through degradation of the minority carrier lifetimes. Solar cell output parameters are compared for four cells, the standard cell (for varying thicknesses), the etched multiple vertical junction cell, and the tandem junction cell. The physical phenomena responsible for poor cell performance at EOL are discussed

Spin-orbit coupling and the conservation of angular momentum

In nonrelativistic quantum mechanics, the total (i.e. orbital plus spin) angular momentum of a charged particle with spin that moves in a Coulomb plus spin-orbit-coupling potential is conserved. In a classical nonrelativistic treatment of this problem, in which the Lagrange equations determine the orbital motion and the Thomas equation yields the rate of change of the spin, the particle's total angular momentum in which the orbital angular momentum is defined in terms of the kinetic momentum is generally not conserved. However, a generalized total angular momentum, in which the orbital part is defined in terms of the canonical momentum, is conserved. This illustrates the fact that the quantum-mechanical operator of momentum corresponds to the canonical momentum of classical mechanics.Comment: 10 pages, as published by Eur. J. Phy

Crossbreeding hogs for pork production

Some 11 or 12 million slaughter hogs are produced on Iowa farms each year. The sale of these hogs produces the largest single item (about 40 percent) of the annual farm income of the state. Any procedure that will produce these hogs more efficiently will increase the net income o f the farmer who uses it, as well as that of the state as a whole

Use of tri-axial accelerometers to assess terrestrial mammal behaviour in the wild

Tri-axial accelerometer tags provide quantitative data on body movement that can be used to characterize behaviour and understand species ecology in ways that would otherwise be impossible. Using tags on wild terrestrial mammals, especially smaller species, in natural settings has been limited. Poor battery power also reduced the amount of data collected, which limits what can be derived about animal behaviour. Another challenge using wild animals, is acquiring observations of actual behaviours with which to compare tag data and create an adequate training set to reliably identify behavioural states. Brown hares were fitted with accelerometers for 5 weeks to evaluate their use in collecting detailed behaviour data and activity levels. Collared hares were filmed to associate actual behaviours with tag data. Observed behaviours were classified using Random Forests (ensemble learning method) to create a supervised model and then used to classify hare behaviour from the tags. Increased tag longevity allowed acquisition of large quantities of data from each individual and direct observation of tagged hare's behaviour. Random Forests accurately classified observed behaviours from tag data with an 11% error rate. Individual accuracy of behaviours varied with running (100% accuracy), feeding (94.7%) and vigilance (98.3%) having the highest classification accuracy. Hares spent 46% of their time being vigilant and 25% feeding when active. The combination of our tags and Random Forests facilitated large amounts of behavioural data to be collected on animals where observational studies could be limited, or impossible. The same method could be used on a range of terrestrial mammals to create models to investigate behaviour from tag data, to learn more about their behaviour and be used to answer many ecological questions. However, further development of methods for analysing tag data is needed to make the process quicker, simpler and more accurate