The relationships between reproductive performance traits of beef bulls in natural mating systems and subjective and objective parameters of sperm and related structures

Twelve Angus and 7 Polled Hereford bulls were used to determine the relationship of various semen quality attributes to various measures of reproductive efficiency. The semen quality characteristics evaluated were: volume, concen-tration, motility, vigor, percent live, percent live normal, percent live immature, percent live normal, percent dead, percent dead normal, percent dead immature, percent dead abnormal and percent intact acrosomes. Scrotal circumference measurements were also taken. Correlations between the semen quality characteristics indicated highly significant relationships between concentration, motility, vigor and percent live and percent dead cells. Sperm morphology classifications were also highly interrelated. Scrotal circumference was not consistently related to any of the ejaculate characteristics. Reproductive performance was evaluated using 3 different expres-sions: the number of estrous cycles the females completed while in the presence of the bull, the mean calving interval for parous, lactating females assigned to each bull and the conception rate for each bull. All calculations were made in an attempt to avoid penalizing the bull for the parity status of the females. Although these traits were highly correlated among themselves, few significant correlations existed with the semen quality characteris-tics. The results of this study indicate the need for an extended study with larger numbers of observations, in order to accomplish more than just defining bulls with increased or impaired fertility

A comparison of the effects of single-trait and multiple-trait sire selection on dairy cattle performance

A total of 477 Holstein cows, with data on 1278 lactations, and 823 conformation classifications were used to study the effects of single-trait and multiple-trait sire selection on production and type classification traits. The production traits studied were mature equivalent milk yield, mature equivalent fat-corrected milk yield, and mature equivalent butterfat yield. The type classification variables studied were total score, and the major breakdown scores, general appearance, dairy character, mammary score, and body capacity. Sires utilized in the mating plan were selected on the basis of either predicted differences for fat-corrected milk (production bulls) or a selection index composed of the predicted difference for fat-corrected milk and mammary scores (merit bulls). Preliminary analyses of variance showed that the effects of month-fresh, line-year, sire, and lactation number (when applicable) were important in the analyses of both the production and type data. Upon adjusting for relationships between sires using Henderson\u27s BLUP procedures, analyses were performed again, and the estimates for line-year were regressed over time to establish genetic trends. The results of the study indicated a positive trend from 1967 to 1982 in production traits, with daughters of the production bulls consistently producing at higher levels of milk and fat than daughters of the merit bulls. When all lactations were included in an analysis, the estimated difference between the lines was less than that estimated by an analysis of first lactation records only. However, the direction of the difference remained the same. Estimate of type classification traits showed a negative trend over time, with daughters of the merit group consistently scoring higher than daughters of the producing group. There were little differences In the results when the analysis Included ratings made of first and second lactation cows or ratings at all ages

When Success Breeds Failure: History, Hysteresis, and Delayed Exit Decisions

The effects of feedback equivocality, information availability, and prior decision-making history on escalation and persistence were investigated. Replicating the findings of J.L. Bragger, D.H. Bragger, D.A. Hantula, and J.P. Kirnan (1998), this study found that participants receiving equivocal feedback on their decisions invested more money and invested across more opportunities; those who could purchase information invested fewer resources than did participants who did not have the opportunity to purchase information. There was an inverse linear relationship between the percentage of opportunities in which participants purchased information and the delay to exit decisions and total resources invested. Six weeks earlier, some participants took part in a more profitable investment scenario, and prior experience led to later increased investing when participants were faced with failure, even above that invested in a preceding, succeeding scenario. These results are consistent with an equivocality theory account of escalation

Using Indirect vs. Direct Measures in the Summative Assessment of Student Learning in Higher Education

Contradictory results have been reported regarding the accuracy of various methods used to assess student learning in higher education. The current study examined student learning outcomes across a multi-section and multi-instructor psychology research course with both indirect and direct assessments in a sample of 67 undergraduate students. The indirect method measured student perceived knowledge and abilities on course topics, while the direct method measured actual knowledge where students answered test questions or solved problems reflecting course content. Both measures independently demonstrated increases from pretest to posttest; however the indirect measure did not correlate with final course grades. Results also showed respondents scoring lower on the direct measure were overconfident (as measured by indirect score) in their perceived knowledge and ability, the Dunning-Kruger Effect. Based on our findings, we concluded that the indirect method was not an accurate measure of student learning, but may have benefits as an instructional tool

Motivating employee referrals: The interactive effects of the referral bonus, perceived risk in referring, and affective commitment

Research has provided compelling evidence that employee referrals result in positive outcomes for organizations and job seekers, but it has been limited on how organizations can increase the likelihood of obtaining employee referrals. Using the theoretical lens of social exchange theory and tenets from expectancy theory, we tested two common assumptions of most employers: A referral bonus motivates employees to refer, and higher bonus amounts incite greater likelihood of referring. We theoretically developed and tested a model integrating the effects of perceived risk in referring and affective commitment and their interactions with the referral bonus to better explain the likelihood of referring. Results largely supported our predictions. Referral bonus presence, referral bonus amount, and affective commitment positively related to likelihood of referring, while perceived risk in referring negatively related to likelihood of referring. The findings also suggest that larger referral bonuses can help offset perceived risk in referring and low affective commitment levels. We contribute to the literature by developing theory, expanding the scope of the current referral literature, and offering a quantitative examination of previously theorized variables in the referring process. We conclude with suggestions to practicing managers on ways to improve the motivating potential of their employee referral programs

A COMPARATIVE ANALYSIS OF THE PRICE-QUALITY RELATION OF AMERICAN AND FOREIGN AUTOMOBILES, 1971-80

This study used hedonic price analysis to investigate the price-quality relation of American and foreign automobiles for the period 1971-80. One of the primary objectives of the study was to determine whether a difference in the price-quality relation for American and foreign automobiles could explain the dramatic increase in the import share of the U.S. new car market that occurred during this period. To conduct the analysis, an extensive automotive data base was developed containing physical and performance characteristics data on more than 1,400 models produced during the sample period. Two separate models were specified, one which evaluated quality in terms of an automobile\u27s physical attributes, the other defining quality on the basis of an automobile\u27s performance characteristics. Separate relationships were estimated for domestic and foreign models for each sub-model for each year from 1971 through 1980. Parameters were also estimated by pooling all domestic and foreign models for each year from 1971 through 1980 and by pooling all models for each two-year period. All estimation was done using ordinary least squares regression analysis. Examination of the regression results suggests a number of important conclusions. First, the results emphasized the importance of both physical and performance characteristics in explaining variation in new car prices for each of the years 1971-80. Second, the study demonstrated quite conclusively that the dramatic increase in import penetration that occurred during the 1970\u27s was primarily due to a decline in the relative price of foreign cars. This was particularly pronounced after 1977, a period which witnessed the largest gains in import penetration. Third, the study found that consumers, in at least a few of the years examined, were willing to pay a higher price for such performance characteristics as acceleration, comfort and fuel economy in a foreign car than in a domestic car. This preference, in addition to the significant decline in the relative price of foreign cars mentioned above, suggests that foreign cars may have enjoyed a distinct quality advantage over American cars during this period

THE RELATIONSHIP OF RECRUITING SOURCE TO APPLICANT QUALITY AND SUBSEQUENT NEW-HIRE SUCCESS CONTROLLING FOR ETHNICITY, SEX AND AGE OF THE APPLICANT

This study investigated both an applicant pool and its resulting class of new hires in an attempt to clarify a number of empirical questions concerning recruiting source effectiveness. The primary objectives of this research were to explore the prescreening hypothesis as an explanation for the effectiveness of informal recruiting sources and to determine if recruiting source effectiveness differed between males and females, non-minorities, Hispanics, and Blacks, or those under 40 years of old and those 40 years or older. A pre-established database of applicants and hires for the job of life insurance agent in a large insurance company were analyzed separately for two years of recruiting activity. The prescreening hypothesis received support when differences in applicant quality, as measured by score on an in-use selection test, the Background Questionnaire, were found in favor of the informal recruiting sources. These recruiting source differences were carried over into the hire sample where informal recruiting sources yielded hires who survived longer than individuals recruited via formal means. A second measure of hire success, new business commission credits, failed to show differences across the recruiting sources. However, data restrictions rendered this measure available for only a subset of hires which may have contributed to its non-significant findings. Selection ratios and frequency of applicant use were also investigated across the recruiting source. The informal sources yielded significantly higher selection ratios than did formal sources. No group differences were found when measuring applicant quality, hire survival or selection ratios. However, the examination of recruiting source use showed significant group differences. Females and Blacks used the formal recruiting sources to a much greater extent than did males and non-minorities/Hispanics. These major findings were found to be consistent over the two years studied giving support to the stability of recruiting source as a measure of applicant and hire effectiveness. While suggesting that informal recruiting sources yield higher quality applicants and more successful hires, the research also cautions that the implementation of revised recruiting policies must be carefully monitored for adverse effects on protected groups