Global gene expression in endometrium of high and low fertility heifers during the mid-luteal phase of the estrous cycle

peer-reviewedBackground In both beef and dairy cattle, the majority of early embryo loss occurs within the first 14 days following insemination. During this time-period, embryos are completely dependent on their maternal uterine environment for development, growth and ultimately survival, therefore an optimum uterine environment is critical to their survival. The objective of this study was to investigate whether differences in endometrial gene expression during the mid-luteal phase of the estrous cycle exist between crossbred beef heifers ranked as either high (HF) or low fertility (LF) (following four rounds of artificial insemination (AI)) using the Affymetrix® 23 K Bovine Gene Chip. Results Conception rates for each of the four rounds of AI were within a normal range: 70–73.3%. Microarray analysis of endometrial tissue collected on day 7 of the estrous cycle detected 419 differentially expressed genes (DEG) between HF (n = 6) and LF (n = 6) animals. The main gene pathways affected were, cellular growth and proliferation, angiogenesis, lipid metabolism, cellular and tissue morphology and development, inflammation and metabolic exchange. DEG included, FST, SLC45A2, MMP19, FADS1 and GALNT6. Conclusions This study highlights, some of the molecular mechanisms potentially controlling uterine endometrial function during the mid-luteal phase of the estrous cycle, which may contribute to uterine endometrial mediated impaired fertility in cattle. Differentially expressed genes are potential candidate genes for the identification of genetic variation influencing cow fertility, which may be incorporated into future breeding programmes.Teagasc Walsh Fellowship Programm

Economic and psychological approaches to risk-bearing : theory and experimental evidence / BEBR No. 603

Title page includes summary.Includes bibliographical references (p. 44-45)

Attitudes Toward Computers: The Impact on Performance

The proliferation of personal computers throughout business environments will continue to place demands on workers at all levels to develop proficient computer skills. A variety of training mechanisms exist that allow workers to introduce, develop, and hone any needed computer skills. Identical training mechanisms, however, are nonetheless likely to result in individuals with different computer abilities (Hicks, Hicks, and Senn, 1991). Existing researchhas examined differences in demographic factors (Dambrot, Silling, and Zook; 1988) as well as differences in attitudes (Torkzadeh and Koufteros, 1993). Much of the research that has examined this area has focused on the changes in attitudes (e.g. computeranxiety) that occur due to a training intervention. Research to date, however, has not extended this effect of training on attitudes as well as to performance. The theory of reasoned action (TRA) (Fishbein and Ajzen, 1975) suggests that attitudes will influence behavior, including performance. The Technology Acceptance Model (TAM) ( Davis, Bagozzi, and Warshaw, 1989) also suggests that attitudes towards use directly influence intentions to use the computer and ultimately actual computer use. Davis et al. demonstrate that an individual\u27s initial attitudes regarding a computer\u27s ease of use and a computer\u27s usefulness influence attitudes toward use. In addition to the attitudes of computer ease of use and computer usefulness, a number of other attitudes related to computer use have been identified in the research literature. Items measuring attitudes examined in this study have been previously defined and used in other studies. The attitudes and measures used in this study were perceived usefulness , perceived ease of use (Davis et al. 1989), computer anxiety (Loyd and Gressard, 1984), anticipation of computer use (Heinssen, Glass, and Knight, 1987), fear of computer use (Heinssen et al.,1987), and attitude toward previous academic achievement. Computer anxiety has been an attitude of primary focus that corresponds closely to the concept of math anxiety (Torkzadeh and Angulo, 1992). Although computer anxiety has definitions ranging from psychological, physical or sociological discomfort to fear. The definition of anxiety in this research referred to the psychological discomfort that might come from using a computer. This discomfort might come from using something unknown, concern over making mistakes or destroying pertinent information. In addition to measuring computer anxiety, we also wanted to measure computer fear. Although extreme anxiety might become fear, there is a distinction between the two constructs. Fear was defined as a trepidation that computers would change something about the individual, such as making the person too dependent on computers. Anticipation was defined as comfort with the idea of learning and using computer skills (Harrison and Ranier, 1992). Academic achievement provided a perceived measure of a subject\u27s past performance in both math and other academic endeavors. The perceived ease of use and usefulness constructs have been well established in the work by Davis et al. (Davis, 1989; Davis, Bagozzi, and Warshaw, 1992). Perceived usefulness was defined as the degree to which a person believes that using a particular system would enhance his or her job performance . Perceived ease of use was defined as the degree to which a person believes that using a particular system would be free of effort (Davis, 1989, pg. 320)

Natural Wormholes as Gravitational Lenses

Visser has suggested traversable 3-dimensional wormholes that could plausibly form naturally during Big Bang inflation. A wormhole mouth embedded in high mass density might accrete mass, giving the other mouth a net *negative* mass of unusual gravitational properties. The lensing of such a gravitationally negative anomalous compact halo object (GNACHO) will enhance background stars with a time profile that is observable and qualitatively different from that recently observed for massive compact halo objects (MACHOs) of positive mass. We recommend that MACHO search data be analyzed for GNACHOs.Comment: 4 pages; plus 4 figures; ReV_TeX 3.0; DOE/ER/40537-001/NPL94-07-01

On the zero-temperature limit of Gibbs states

We exhibit Lipschitz (and hence H\"older) potentials on the full shift $\{0,1\}^{\mathbb{N}}$ such that the associated Gibbs measures fail to converge as the temperature goes to zero. Thus there are "exponentially decaying" interactions on the configuration space $\{0,1\}^{\mathbb Z}$ for which the zero-temperature limit of the associated Gibbs measures does not exist. In higher dimension, namely on the configuration space $\{0,1\}^{\mathbb{Z}^{d}}$, $d\geq3$, we show that this non-convergence behavior can occur for finite-range interactions, that is, for locally constant potentials.Comment: The statement of Theorem 1.2 is more accurate and some new comment follow i

Effects of negative energy balance on liver gene and protein expression during the early postpartum period and its impacts on dairy cow fertility

End of project reportNegative energy balance (NEB) is a severe metabolic affecting high yielding dairy cows early post partum with both concurrent and latent negative effects on cow fertility as well as on milk production and cow health. The seasonal nature of Irish dairy production necessitates high cow fertility and a compact spring calving pattern in order to maximise grass utilisation. Poor dairy cow reproductive performance currently costs the Irish cattle industry in excess of €400 million annually. High milk yields have been associated with lower reproductive efficiency, and it has been suggested that this effect is probably mediated through its effects on the energy balance of the cow during lactation. The modern high genetic merit dairy cow prioritises nutrient supply towards milk production in early lactation and this demand takes precedence over the provision of optimal conditions for reproduction. In this study we used the bovine Affymetrix 23,000 gene microarray, which contains the most comprehensive set of bovine genes to be assembled and provides a means of investigating the modifying influences of energy balance on liver gene expression. Cows in severe negative energy balance (SNEB) in early lactation showed altered hepatic gene expression in metabolic processes as well as a down regulation of the insulin-like growth factor (IGF) system, where insulin like growth factor-1 (IGF-1), growth hormone receptor variant 1A (GHR1A) and insulin-like growth factor binding protein-acid labile subunit (IGFBP-ALS) were down regulated compared to the cows in the moderate negative energy balance MNEB group, consistent with a five-fold reduction in systemic concentrations of IGF1 in the SNEB group.Cows in SNEB showed elevated expression of key genes involved in the inflammatory response such as interleukin-8 (IL-8). There was a down regulation of genes involved in cellular growth in SNEB cows and moreover a negative regulator of cellular proliferation (HGFIN) was up regulated in SNEB cows, which is likely to compromise adaptation and recovery from NEB. The puma method of analysis revealed that 417 genes were differentially regulated by EB (P<0.05), of these genes 190 were up-regulated while 227 were down-regulated, with 405 genes having known biological functions. From Ingenuity Pathway Analysis (IPA), lipid catabolism was found to be the process most affected by differences in EB status

The politics of pedagogical reform.

Abstract not availabl