Delayed Insemination of Non-Estrual Beef Heifers in 7-day CO-Synch Timed Artificial Insemination

Reproductive performance in cattle is considered to be the most economically important trait and is essential for the success of an operation. In the last decade, timed artificial insemination (AI) in the beef cattle industry has increased in popularity due to the decreased amount of labor required for estrous detection. To increase the use of AI; however, cost and time inputs need to be further decreased. The objective of this study was to determine if fertility could be improved in beef heifers that are not expressing estrus before timed AI by delaying insemination

Three Essays Examining the Behavioral and Socioeconomic Transition to Adulthood in the United States and Africa: Evidence from Longitudinal Studies.

This dissertation examines elements of adolescents’ socioeconomic and behavioral transition to adulthood. It consists of three separate studies, each relying on a different large-scale panel study that follows the same set of young people over time. Two of the studies examine adolescents in the contemporary United States while the other examines adolescents in contemporary urban South Africa. In the second chapter, I examine whether or not changes in the structure of U.S. social welfare policies in the mid-1990s, specifically those that incentivized and tied social support to participation in the paid labor force, had any effect on rates of U.S. long-term child poverty. I find that long-term poverty dropped substantially for black and white children of the post-reform cohort, with about 1 in 5 black children and 3.6 percent of white children classified as long-term poor, compared to pre-reform rates of 1 in 3 black children and 5.8 percent of white children. In the third chapter, I examine the link between contextual disadvantage and the likelihood that an adolescent’s relationship is “embedded” in common social contexts and peer groups. I find that adolescents form relationships with partners from various contexts and that neighborhood and school disadvantage help determine the social contexts from which adolescents know their partners. In the fourth chapter, I examine the link between paternal absence and sexual debut among adolescents in Cape Town, South Africa. I find that the absence of a father from a child’s household, net of other observed factors, increases the likelihood of adolescent sexual debut by age 16, although the effect differs by race and gender. In sum, the examination of race and gender differences inherent in each of these studies reminds social scientists that the social environment external to an individual interacts with the individual’s personal characteristics, implying that there is heterogeneity in the “effects” of the family and social context on individual outcomes and that understanding these heterogeneous effects among adolescents is required for moving toward a more holistic, life-course understanding of the racial and gender differences observed in adult outcomes.Ph.D.Public Policy & SociologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78811/1/lgrieger_1.pd

Comparison of particle trajectories and collision operators for collisional transport in nonaxisymmetric plasmas

In this work, we examine the validity of several common simplifying assumptions used in numerical neoclassical calculations for nonaxisymmetric plasmas, both by using a new continuum drift-kinetic code and by considering analytic properties of the kinetic equation. First, neoclassical phenomena are computed for the LHD and W7-X stellarators using several versions of the drift-kinetic equation, including the commonly used incompressible-ExB-drift approximation and two other variants, corresponding to different effective particle trajectories. It is found that for electric fields below roughly one third of the resonant value, the different formulations give nearly identical results, demonstrating the incompressible ExB-drift approximation is quite accurate in this regime. However, near the electric field resonance, the models yield substantially different results. We also compare results for various collision operators, including the full linearized Fokker-Planck operator. At low collisionality, the radial transport driven by radial gradients is nearly identical for the different operators, while in other cases it is found to be important that collisions conserve momentum

Detection of broken rotor bar faults and effects of loading in induction motors during rundown

© Copyright 2007 IEEEThe detection of broken rotor bar faults based on the common steady-state Fourier transform technique is known to be dependent on the loading condition and the quality of the supply. This paper attempts to minimise these issues by utilising the induced voltage in the stator windings after supply disconnection. When the supply is disconnected, the stator current rapidly drops to zero and the only source of the stator induced voltage an instant after the supply disconnection is due to currents in the rotor. The rotor currents are sensitive to broken rotor bar faults and directly affect the rundown induced voltage in the stator windings. The performance of two different broken rotor bar detection techniques, based on the Fourier transform and the wavelet transform, are investigated over a wide range of loading conditions

Investigation of static eccentricity fault frequencies using multiple sensors in induction motors and effects of loading

A significant number of studies have been reported in the literature on the detection of eccentricity faults in induction machines; however these have generally used one type of sensor such as current or vibration, and not studied in detail the effect of loading. This paper examines the use of fault frequency components in the current, flux and vibration sensor signals with the aim of both detecting and estimating the severity of static eccentricity faults in the presence of load variations. The research is based on an extensive series of sensor measurements taken using a specially modified 2.2kW induction machine under varying conditions of static eccentricity and loading.R. Supangat, J. Grieger, N. Ertugrul, W.L. Soong, D.A. Gray, C. Hanse

Using Estrus-Detection Patches to Vary Time of Insemination Improves Pregnancy Rates Compared with One Single Timed Insemination

Timed artificial insemination (TAI) of beef cows at a predetermined time is a management tool that reduces labor costs associated with conventional heat detection before insemination. Multiple research trials have examined timing of the individual components of the developed protocols associated with TAI. The 7-day CO-Synch + progesterone insert (controlled internal drug release; CIDR) protocol has been shown to initiate ovulation effectively in cycling and noncycling suckled beef cows, often producing pregnancy rates greater than 50% in beef cows. In the current research, we examined using two targeted insemination intervals depending on the occurrence of estrus. We hypothesized that by more closely synchronizing estrus and insemination that pregnancy rates would be increased. We further hypothesized that cows that do not demonstrate estrus and are subjected to a TAI protocol might benefit from an increased interval to insemination

Using Estrus-Detection Patches to Vary Time of Insemination Improves Pregnancy Rates Compared with One Single Timed Insemination

Timed artificial insemination (TAI) of beef cows at a predetermined time is a management tool that reduces labor costs associated with conventional heat detection before insemination. Multiple research trials have examined timing of the individual components of the developed protocols associated with TAI. The 7-day CO-Synch + progesterone insert (controlled internal drug release; CIDR) protocol has been shown to initiate ovulation effectively in cycling and noncycling suckled beef cows, often producing pregnancy rates greater than 50% in beef cows. In the current research, we examined using two targeted insemination intervals depending on the occurrence of estrus. We hypothesized that by more closely synchronizing estrus and insemination that pregnancy rates would be increased. We further hypothesized that cows that do not demonstrate estrus and are subjected to a TAI protocol might benefit from an increased interval to insemination

Energetic ion loss diagnostic for the Wendelstein 7-AS stellarator

A diagnostic to measure the loss of energetic ions from the Wendelstein 7-AS (W7-AS) stellarator has been built. It is capable of measuring losses of both neutral beam ions and energetic ions arising from ion cyclotron resonant heating. The probe can measure losses of both clockwise and counterclockwise-going energetic ions simultaneously, and accepts a wide range of pitch angles in both directions. Initial measurements by the diagnostic are reported