3,508 research outputs found
Genetic relationship of yield and fertility in dairy cattle
Breeding information and records of yield for dairy cows from the northeast part of the United States were evaluated. Nine measures of yield were age adjusted by multiplicative factors. Ten measures of fertility were defined. Records for first parity (41,710), second parity (31,162), third parity (22,389), and virgin heifers (15,357) were analyzed;Repeatabilities for pairwise combinations of first three lactations were .32 to .61 for measures of yield and .01 to .16 for measures of fertility. Repeatabilities of virgin heifer fertility with first parity fertility were .01 to .03;Heritabilities of yield were .10 to .18 for first parity by Henderson\u27s Method 3, but estimates from restricted maximum likelihood were .23 for 305-day milk both fat-corrected and on a mature equivalent basis. Heritabilities of fertility were zero to .03 for all parities. Virgin heifer heritabilities of fertility were slightly higher;Phenotypic correlations of yield and fertility were small and antagonistic for measures of yield early in lactation, but became more antagonistic with advancing gestation for measures of yield later in lactation. Yield and fertility for first parity were distinctly antagonistic, genetically. Genetic correlations tended to moderate for second parity, and the genetic relations between measures of yield and fertility for third parity were not conclusive and had large standard errors;Phenotypic correlations of virgin heifer fertility and first parity yield were near zero; genetic correlations tended to be complementary. Virgin heifer fertility and first parity fertility had opposite genetic relationships with first parity yield. Comparing fertility for virgin heifers and first parity cows, phenotypic correlations were near zero, and genetic correlations usually were not significantly different from zero and showed little indication of being consistent in sign;Index selection of sire progeny was applied to 305-day milk which was fat corrected and days open. Considerable economic weight had to be assigned to days open for days open to influence the index to a meaningful extent due to the low heritability of days open
Who Owns the Law? Why We Must Restore Public Ownership of Legal Publishing
Each state has its own method for officially publishing the law. This article looks at the history of legal publishing for the fifty states before looking at how legal publishing even in moving to electronic publishing may not ensure public access to the law. The article addresses barriers to free access to the law in electronic publishing including copyright, contract law, and potentially, the Computer Fraud and Abuse Act. The article concludes with prescriptions for how different actors, including state governments, publishers, libraries, and others can ensure robust public access to the law moving forward
Persistency of Priors-Induced Bias in Decision Behavior and the fMRI Signal
It is well known that people take advantage of prior knowledge to bias decisions. To investigate this phenomenon behaviorally and in the brain, we acquired fMRI data while human subjects viewed ambiguous abstract shapes and decided whether a shape was of Category A (smoother) or B (bumpier). The decision was made in the context of one of two prior knowledge cues, 80/20 and 50/50. The 80/20 cue indicated that upcoming shapes had an 80% probability of being of one category, e.g., B, and a 20% probability of being of the other. The 50/50 cue indicated that upcoming shapes had an equal probability of being of either category. The ideal observer would bias decisions in favor of the indicated alternative at 80/20 and show zero bias at 50/50. We found that subjects did bias their decisions in the predicted direction at 80/20 but did not show zero bias at 50/50. Instead, at 50/50 the subjects retained biases of the same sign as their 80/20 biases, though of diminished magnitude. The signature of a persistent though diminished bias at 50/50 was also evident in fMRI data from frontal and parietal regions previously implicated in decision-making. As a control, we acquired fMRI data from naïve subjects who experienced only the 50/50 stimulus distributions during both the pre-scan training and the fMRI experiment. The behavioral and fMRI data from the naïve subjects reflected decision biases closer to those of the ideal observer than those of the prior knowledge subjects at 50/50. The results indicate that practice making decisions in the context of non-equal prior probabilities biases decisions made later when prior probabilities are equal. This finding may be related to the “anchoring and adjustment” strategy described in the psychology, economics, and marketing literatures, in which subjects adjust a first approximation response – the “anchor” – based on additional information, typically applying insufficient adjustment relative to the ideal observer
The Effects of Three Selected Weight Training Programs on Muscular Strength, Endurance Girth, and Cardiovascular Endurance
The purpose of this investigation was to compare the effects of three different weight training programs on the development of muscular strength, muscular endurance, muscular girth, and cardiovascular endurance. Thirty freshman and varsity football players from the 1968 South Dakota State University football teams were used as subjects. The subjects were randomly divided into three different groups. One group trained using a modification of the DeLorme-Watkins method of training; the second group followed the traditional strength training method, while the third followed a circuit training program. The conditioning programs for the three groups consisted of ten exercises: bench press, military press, two arm curl, erect rowing, lat exercise, sit-up, bent rowing, leg press, heel raisers, and dead lift. Training covered a period of seven weeks, with the subjects meeting on Monday, Wednesday, and Friday for twenty-one training sessions. Tests for muscular strength, endurance, and girth were administered before the program began, at the end of three weeks of training, and at the conclusion of the training program. Cardiovascular endurance was determined and data were recorded at the beginning and at the end of the training program. Two weeks separated the initial test and the start of the program because of the semester break. Within the limitations of this study, the following conclusions were made: 1. The three training programs used for this study all improved strength, muscular endurance, girth, and cardiovascular endurance. 2. The modified DeLorme-Watkins, traditional strength, and circuit training programs produced basically the same results for muscular strength, endurance and girth; however, the circuit training program produced the best results for cardiovascular endurance. 3. Since the three methods of weight training produced basically the same results, the investigator suggests the use of circuit training for the development of physical fitness due to the shorter period of time required to complete the daily training program
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Functional and Genomic Analyses of Klebsiella Pneumoniae Population Dynamics in the Gastrointestinal Tract
The gastrointestinal tract is home to trillions of bacteria that interact with each other and with the host’s mucosal immune system. Obligate and facultative anaerobes thrive in the small and large intestine. While many of these bacteria have beneficial relationships with their host, opportunistic pathogens can bloom in times of inflammation and prolong disease. Klebsiella pneumoniae is an opportunistic pathogen that is part of the gut microbiota in many healthy individuals. Here we explore the population dynamics of K. pneumoniae in the gastrointestinal tract in mouse models of health and disease.
To assess the role of intra-species genomic diversity in interactions with the host, a mouse K. pneumoniae isolate and three human clinical isolates from human stool, sputum, and urine were studied in the T-bet-/- Rag2-/- and dextran sodium sulfate models of ulcerative colitis and in a mouse model of systemic neonatal infection. Regardless of host origin, isolate site source, or genomic differences, all four K. pneumoniae isolates were able to stimulate colonic inflammation. However, only exposure to the murine K. pneumoniae isolate, and not human clinical isolates, led to neonatal death. In addition, this murine isolate correlated with differential shifts in levels of other Enterobacteriaceae species in the colon. Murine K. pneumoniae was found in higher amounts in host mesenteric lymph nodes compared to human isolates, suggesting subtle strain-based differences that affect response to K. pneumoniae in the gastrointestinal tract.
A defining feature of K. pneumoniae is its mucoid capsular polysaccharide coat. To begin investigating a role for K. pneumoniae’s capsule in the gastrointestinal tract, K. pneumoniae biogeography was assessed in gnotobiotic mice. Encapsulated K. pneumoniae were outcompeted by naturally arising variants with reduced capsule throughout the gastrointestinal tract of gnotobiotic mice, except in the distal small intestine. This portion of the small intestine was also the region with the highest host Paneth cell antimicrobial peptide expression. Micro-injection of K. pneumoniae into small intestinal organoids revealed increased growth of encapsulated K. pneumoniae in the presence of α-defensins and decreased survival of K. pneumoniae with reduced capsule production. Capsule also conferred an advantage when K. pneumoniae was part of a diverse microbiota. Competition assays between K. pneumoniae and Escherichia coli showed enhanced survival of encapsulated K. pneumoniae compared to isolates with reduced capsule production. These data suggest that host AMPs, in combination with bacterial-bacterial interactions, shape population dynamics of K. pneumoniae and select for encapsulated K. pneumoniae throughout the gastrointestinal tract. Overall, these studies provide a foundation for understanding interactions between K. pneumoniae, the host, and other bacteria in the gastrointestinal tract.Medical Science
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