Hypervelocity impact testing of cables

The physics and electrical results obtained from simulated micrometeoroid testing of certain Skylab cables are presented. The test procedure, electrical circuits, test equipment, and cable types utilized are also explained

Videomicroscopic Comparison of Bull Sperm and Leukocyte Chromosome Areas as Related to Gender

Chromosomal areas from metaphase spreads of male bovine leukocytes were digitized and sex chromosomes identified using videomicroscopy. Autosomal areas were ranked in descending order within a cell and assigned to two categories based on alternating rank. X and Y chromosome areas were assigned to respective categories. Areas were divided by 4 to make their sum equivalent to sperm DNA content. Data were analyzed before and after inclusion of sex chromosomal areas. Before X and Y inclusion, rank contributed to difference in chromosomal areas. Rank by category interaction and category effects did not contribute to area variation. After X and Y inclusion, area variation was due to rank by category interaction, rank, and category. Differences between sums of chromosomal areas across categories was 3.57%. Head areas of morphologically normal sperm with intact acrosomes were digitized using the same optics as chromosomal areas. Sum of corrected chromosomal areas per category was used in discriminant analysis to assign sperm head areas to two categories with .5 prior probabilities. Assignment resulted in 1037 sperm in one category and 1177 in the other. Difference between largest sperm head area classes across categories was 3.2%. Discriminatian of sperm head areas, based on sum of chromosomal area and measured with computerized videomicroscopy, may be used to evaluate sex of bovine spermatozoa. © 1990, American Dairy Science Association. All rights reserved

Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations.

Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma

Thawing Optimums for Bovine Spermatozoa Processed by Three Methods and Packaged in Continental and French Straws

A modified two-dimensional central composite rotatable design was used to study the effect of thaw bath temperature and time on acrosomal integrity in Continental (.3 ml) and French (.5 ml) straws. Ejaculates from 18 bulls were packaged in both containers. Semen from 6 of the 18 bulls was processed by each of three methods: 6 bulls for egg yolk- Tris-glycerol, 6 bulls for egg yolk-citrate-glycerol, and 6 bulls for skim milk- glycerol. Thaw bath temperatures ranged from 18 to 92° C, and thaw times ranged from 4.5 to 50 s. Interaction of thaw bath temperature with thaw time was detected within each processing procedure and package. Maximum cell quality, measured by intact acrosomes after incubation of semen 3 h at 37°C for .3-ml and .5-ml straws, was predicted to be achieved by thaw bath temperatures and times (°C/s) as follow: egg yolk-Tris-glycerol 40/32, 49/16; egg yolk-citrate- glycerol 43/30, 37/19; skim milk-glycerol 50/24, 36/24. Thawing procedures to maintain best acrosomal retention, regardless of processing method, were 44° C for 29 s for .3-ml straws and 40°C for 20 s for .5-ml straws. © 1984, American Dairy Science Association. All rights reserved

Use of Linear Semen Quality Score for Classification and Decision Making in Evaluation of Individual Ejaculates of Holstein Bulls

Four hundred seven ejaculates from 15 Holstein bulls collected from December 1984 to June 1985 were evaluated postthaw for viability characteristics (percent progressive motility at 0 h and after 3 h at 37°C incubation, percent intact acrosomal membrane after 3 h at 37°C incubation) and abnormal morphological characteristics [percent head (primary), midpiece, and tail (secondary) abnormalities]. Weighting coefficients for combining viability and abnormality characteristics were generated from between-bull and within-bull variance and covariance matrices. Two hundred ninety-eight additional ejaculates collected from July 1985 to February 1986 were added. Linear quality scores for 705 ejaculates (24 bulls) were the sum of the product of each quality characteristic and weighting coefficients. Univariate analysis yielded significant bull effects for viability and abnormality characteristics and linear quality score. Significant correlations existed between all seminal quality characteristics except primary and secondary abnormalities. A t test with preassigned critical value was used to evaluate each ejaculate to determine rejection from the population. Percent of ejaculates rejected was lower when linear quality score was used than when five independent tests were used. Use of linear quality score to critique semen based on each ejaculate\u27s innate quality could compensate for the loss of bull fertility estimates from declining number of technician-based AI programs. © 1987, American Dairy Science Association. All rights reserved

Relationship between Final Temperature, Thaw Rate, and Quality of Bovine Semen

Relationships between thaw rate, thaw bath time, and initial bath and final seminal temperature with coefficients of determination .99 and .97 were: bath time = −.01 + 220.25(1/thaw rate); initial bath temperature = final seminal temperature − 7.29 + 390.05(1/bath time). Ejaculates from 10 bulls were split and processed in egg yolk-citrate-glycerol, egg yolk-Tris-glycerol, and whole milk-glycerol. All semen was packaged and frozen in .5-ml French straws at −196°C. Sixteen thaw treatments consisted of factorial combinations of four final seminal temperatures and four thaw rates. Treatments were assessed by post-thaw acrosomal integrity after 3-h 37°C incubation. Seminal quality improved with increasing final seminal temperature up to 31°C and did not differ between 31 and 44°C for any of the extenders. A slow thaw rate (3°C/s) resulted in inferior quality for all extenders, and rates 11, 19, and 27°C/s resulted in similar quality for citrate and milk extended semen. Acrosomal integrity was most for 19°C/s in Tris extended semen. A significant factorial interaction existed for Tris and milk extended semen. Predicted acrosomal response of 57.7% across all extenders was at optimum final seminal temperature and thaw rate 37°C and 18°C/s. Bath temperature and bath time determine optimum thaw rate and final temperature of semen packaged in French straws and thus maximize seminal quality. © 1984, American Dairy Science Association. All rights reserved

Environmental and Genetic Sources of Variation for Seminal Quality in Mature Holstein Bulls

Various environmental and genetic factors that influence seminal quality were evaluated for 149 Holstein bulls used extensively in nine artificial insemination organizations (studs). These bulls were sons of 16 sires. Seminal quality was measured by percent progressive motility immediately postthaw and after incubation at 3 h, 37°C, percent intact acrosomal membrane after incubation at 3 h 37°C, and percent primary and secondary abnormalities. Semen was thawed at 37 and 24°C. Spermatozoal concentration was counted with a hemocytometer. Bull age and season of collection were determined. Interaction of stud × thaw existed for both motility assessments and intact acrosomes, but 37°C thaw resulted in higher motility and acrosomal integrity across all studs. Motility at zero hour was affected by season. Secondary abnormalities were influenced by season and stud × season. Interaction of thaw × season existed for incubated motility, which also was influenced by concentration and age. Age influenced secondary abnormalities. Heritabilities and repeatabilities (%) were .21, 44; .40, 34; .81, 74; and .31, 50 for 0-h motility, intact acrosomes, primary abnormalities, and secondary abnormalities. Genetic correlations were 0-h motility with acrosomal integrity and primary and secondary abnormalities, .88, −.70, −.93; acrosomal integrity with primary and secondary abnormalities, −.90, −.05; primary with secondary abnormalities, −.12. Selection for semen quality could improve fertility of bulls. © 1985, American Dairy Science Association. All rights reserved

Chromosome and Sperm Size of Holsteins with and Without Bovine Leukocyte Adhesion Deficiency

The objective was to evaluate bull differences in chromosomal and spermatozoal areas related to the occurrence of the bovine leukocyte adhesion deficiency syndrome. Lymphocyte chromosomes from 30 Holstein bulls and 2 Holstein heifers were measured using image analysis and computer-enhanced video-microscopy. Spermatozoal head areas from 29 of the 30 bulls were measured. Autosomal rank was based on decreasing area. Average total autosomal areas were not the same across bulls. One group of bulls had significantly smaller average chromosomal areas than the others; this group carried bovine leukocyte adhesion deficiency syndrome. Area measures of spermatozoal heads showed that bulls with bovine leukocyte adhesion deficiency syndrome had significantly larger head areas than normal bulls. Lymphocyte chromosomes from 3 cattle that were homozygous for bovine leukocyte adhesion deficiency syndrome were significantly smaller than chromosomes from syndrome heterozygotes. Carrier identification was improved by the use of autosomal and sperm area measurements in addition to pedigree evaluation. © 1994, American Dairy Science Association. All rights reserved

Protein Solubility, In Vitro Ammonia Concentration, and In Situ Disappearance of Extruded Whole Cottonseed and Other Protein Sources

Whole cottonseed extruded at temperatures (°C) and rates (kg/h) of 131, 314; 135, 182; 146, 195; and 156, 286 was evaluated by protein solubility, in vitro ammonia concentration, and in situ disappearance techniques. These techniques were used to estimate potential of extruded whole cottonseed for protein escape from the rumen. In addition, raw whole cottonseed, soybean meal, corn gluten meal, and whole cottonseed and soybean meal heated for 4 h at 127, 138, and 149°C were used for comparison. Solubility was by three methods: cold water mixed for 30 min, cold water homogenized for 5 s, and hot water refluxed for 1 h. In vitro ammonia concentration was measured after 2, 4, and 6 h of incubation. Dry matter and CP disappearance was estimated using nylon bags suspended in the rumen for 1, 2, 4, 8, 12, and 24 h. Extrusion reduced solubility of cottonseed as measured by all three methods. There was no difference in ammonia concentration due to extrusion. Whole cottonseed responded similarly to extruded products at all time intervals. Extruded products differed over time with the in situ technique. The two highest extrusion temperatures resulted in mean DM and CP disappearance rates of 1.32 and 1.32%/h compared with whole cottonseed (1.52, 6.08) and the other extrusion treatments (1.96, 2.92). © 1988, American Dairy Science Association. All rights reserved

Sex Ratio Variation between Ejaculates Within Sire Evaluated by Polymerase Chain Reaction, Calving, and Farrowing Records

Ejaculates from sires were examined by polymerase chain reaction to determine percentage of sperm bearing the Y chromosome. Results were verified by examining the percentage of male calves per ejaculate used in artificial insemination (AI) and the percentage of male piglets per litter from a controlled mating program. Spermatozoal DNA was amplified by polymerase chain reaction with specific primers for the Y chromosome. Image analysis measured the fluorescent intensity of the 194-bp band. Ejaculates were compared with a pooled standard of spermatozoal DNA equated to a 50% Y-bearing sperm ejaculate. Calving data were obtained from information collected for the National Association of Animal Breeders for dystocia evaluation of cows bred to AI bulls. Breeding data were obtained from AI technician receipts. Calving and breeding data were merged on cow, sire, calving date, and breeding date. The percentage of males was calculated per sire, ejaculate, and herd combination. Farrowing data were evaluated for the percentage of male piglets per litter. Ejaculates within bulls contributed to variation (24 ± 9.8% to 84 ± 9.8%) in the percentage of sperm bearing the Y chromosome. Ejaculates from the same bull contributed to variation in the percentage of male calves (16.1 to 72.3%). Ejaculates from the same boar contributed to variation in the percentage of male piglets that ranged from 7.8 to 94.7%. These percentages and the results obtained by polymerase chain reaction analysis of ejaculates suggested that spermatozoa bearing X and Y chromosomes were unequally represented in ejaculates. The use of ejaculates screened by polymerase chain reaction could enhance production of the desired sex of calf