1,436 research outputs found

    Studies relating to protein expression in the uterus of the cow

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    End of project reportEmbryo loss is a major cause of reproductive wastage in the cow. The majority of embryo loss occurs in the first 16 days after fertilisation when the embryo is critically dependent on the maternal uterine environment for survival. Despite the central role of uterine fluid in the normal growth and development of the embryo, there is limited information on the protein composition of these fluids. The main objectives of the studies in this thesis were to examine the protein composition of the bovine uterus during the oestrous cycle and to examine the relationship between the concentration of systemic progesterone and uterine protein expression in the cow. In the first study, the concentration of retinol-binding protein (RBP) in the bovine uterus was found to vary across the cycle and was 5-15-fold higher (P0.05) of the cycle, which was surprising given that previous studies have indicated that uterine RBP gene expression was positively associated with the concentration of systemic progesterone. In the second study, IGF binding protein 2 (IGFBP-2), IGFBP-3, IGFBP-4 and IGFBP-5 were identified in uterine fluid on days 3, 7, 11 and 15 of the oestrous cycle. There was a local effect on the concentration of IGFBPs where the concentration was greater on the ipsilateral side than that on the contralateral side for IGFBP-2 (P<0.05), 3 (P<0.01) and 5 (P<0.01) on day 15. This difference is a further indication of a local controlling mechanism regulating proteins between the uterine horns. Similar to RBP expression this study could find no significant relationship between the concentration of systemic progesterone and IGFBP concentrations on Day 7 of the oestrous cycle. In the third study, changes in the global pattern of uterine proteins between Days 3 and Day 15 of the oestrous cycle were examined using two-dimensional electrophoresis (2-DE). Six proteins were found to be upregulated on Day 15 compared to Day 3. Three proteins of these were identified as aldose reductase, plakoglobin and heat shock protein 27 while the other three proteins were identified as bovine serum albumin. Aldose reductase, an enzyme directly involved in the production of sorbitol and indirectly of fructose, was 10-fold higher (P<0.0001) on Day 15 compared to Day 3. Plakoglobin (Pg) was upregulated 2.3-fold (P<0.0001) on Day 15 compared to Day 3. Pg is a component of cellular junctions and its up-regulation may have a role in the uterine glandular epithelium. Heat shock protein 27 (Hsp27) was higher on Day 15 than on Day 3 (P<0.01) and Hsp27 was 1.4-fold higher in the ipsilateral compared to the contralateral uterine horn (P<0.01). Hsp27 may be secreted in response to potential stresses in the uterus or act as a molecular chaperone. On Day 7 there was no difference (P<0.05) in the pattern of proteins secreted between cows with low (2.7±0.10ng/ml) and high (4.8±0.13 ng/ml) concentrations of systemic progesterone on Day 7. The results of these studies have shown that dramatic changes occur in protein expression across the bovine oestrous cycle. Additionally, it emphasises the need for gene studies to be followed with protein studies as an adjunct or complementary tool. Proteins have a wide range of essential roles in the uterus and together these studies provide novel information on protein expression in the uterus of the cow

    Policy Insights from Comparing Carbon Pricing Modeling Scenarios

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    Carbon pricing is an important policy tool for reducing greenhouse gas pollution. The Stanford Energy Modeling Forum exercise 32 convened eleven modeling teams to project emissions, energy, and economic outcomes of an illustrative range of economy-wide carbon price policies. The study compared a coordinated reference scenario involving no new policies with policy scenarios that impose a price on all fossil fuel-related carbon dioxide (CO2) emissions in the U.S. The CO2 price scenarios begin in 2020 at 25/tonor25/ton or 50/ton and rise each year over inflation at one percent or five percent. The scenarios also vary by the use of the revenue from the carbon pricing policy; scenarios include rebates to households and deficit neutral reductions in marginal tax rates on capital and labor income. Across all models and policy scenarios, the study finds that carbon pricing leads to significant reductions in CO2 emissions, the majority of which occur in the electricity sector via the reduction of coal use. Policy effects on other energy sources vary by model, for example owing to different technology cost assumptions (e.g., cost of natural gas vs. wind generation). Some models translate energy shifts into changes in conventional air pollutants, reporting declines consistent with substantial air quality benefits from the policy scenarios. The economic costs of the policies are expected to be modest – allowing for nearly identical economic growth– but vary across models. These costs are offset by benefits from avoided climate damages (which are not modeled in this study) and health benefits from reductions in conventional air pollution. The study finds that the CO2 taxes generate significant revenue; a 25/tonpricewouldgenerateroughly25/ton price would generate roughly 1.4 trillion over the first decade and all models reported that emissions reductions do not significantly depend on the use of the revenue. Using revenues to reduce capital or labor taxes reduces economy-wide costs in most models relative to household rebates, but the estimated size of the cost reductions varies significantly across models. Across all models that estimated impacts across households, devoting at least some revenue to household rebates improves outcomes for low income households relative to applying all revenue to reductions in other taxes. We focus here on results through 2030, concluding that beyond a decade model uncertainties are too large to make quantitative results useful for near-term policy design

    Multi-wire proportional counter for soft x-ray detection

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    Control of Ovulation Rate in Beef Cattle.

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    End of Project ReportUnder intensive production systems, the greatest potential for effecting increases in production and economic efficiency in the beef cow herd lies in the possibility of increasing the frequency of twin births. Embryo transfer is technically a successful method of inducing twin births in cattle. While an embryo transfer approach is too costly to allow commercial twinning, it has been used to show that ovulation rate and not uterine capacity is the limiting factor in increasing the reproductive rate of the cow. While ovulation of one or more viable oocytes is central to normal reproduction, knowledge of the control of ovulation and of folliculogenesis on which ovulation depends, is limited. In spite of the fact that many follicles are subjected to the same endogenous hormonal environment and theoretically should all be capable of ovulating, only a tiny proportion do. While gonadotrophic hormones play a central role in ovarian follicle development and ovulation, their action at the ovarian level seems to be controlled by intra-ovarian factors. This intra-ovarian control of ovulation is thought to be exerted partly by the hormone inhibin and partly by other, as yet, unidentified compounds in follicular fluid. This project focused on identification and isolation of ovarian compounds involved in the control of ovulation rate, followed by immunisation against these compounds in order to study the effect on ovulation and the twin calving rates. The main results are summarised here and detailed results have been published in the papers listed at the end of this report

    Policy Insights From the EMF 32 Study on U.S. Carbon Tax Scenarios

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    The Stanford Energy Modeling Forum exercise 32 (EMF 32) used 11 different models to assess emissions, energy, and economic outcomes from a plausible range of economy-wide carbon price policies to reduce carbon dioxide (CO2) emissions in the United States. Here we discuss the most policy-relevant results of the study, mindful of the strengths and weaknesses of current models. Across all models, carbon prices lead to significant reduc- tions in CO2 emissions and conventional pollutants, with the vast majority of the reductions occurring in the electricity sector. Importantly, emissions reductions do not significantly depend on the rebate or tax cut used to return revenues to the economy. Expected economic costs, as modeled by either GDP or welfare, are modest, but vary across models. These costs are offset by benefits from avoided climate damages and health benefits from reductions in conventional air pollution. Using revenues to reduce preexisting capital or labor taxes reduces costs in most models relative to lump-sum rebates, but the size of the cost reductions varies significantly. Devoting at least some revenue to household rebates can significantly reduce adverse impacts on low income households. Carbon prices at $25/ton or even lower levels cause significant shifts away from coal as an energy source with responses of other energy sources highly dependent upon technology cost assumptions. Beyond 2030, we conclude that model uncertainties are too large to make quantitative results useful for near-term policy design. We close by describing recommendations for policymakers on interacting with model results in the future

    When is rotational angiography superior to conventional single-plane angiography for planning coronary angioplasty?

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    Objectives: To investigate the value of rotational coronary angiography (RoCA) in the context of percutaneous coronary intervention (PCI) planning. Background: As a diagnostic tool, RoCA is associated with decreased patient irradiation and contrast use compared with conventional coronary angiography (CA) and provides superior appreciation of three-dimensional anatomy. However, its value in PCI remains unknown. Methods: We studied stable coronary artery disease assessment and PCI planning by interventional cardiologists. Patients underwent either RoCA or conventional CA pre-PCI for planning. These were compared with the referral CA (all conventional) in terms of quantitative lesion assessment and operator confidence. An independent panel reanalyzed all parameters. Results: Six operators performed 127 procedures (60 RoCA, 60 conventional CA, and 7 crossed-over) and assessed 212 lesions. RoCA was associated with a reduction in the number of lesions judged to involve a bifurcation (23 vs. 30 lesions, P < 0.05) and a reduction in the assessment of vessel caliber (2.8 vs. 3.0 mm, P < 0.05). RoCA improved confidence assessing lesion length (P = 0.01), percentage stenosis (P = 0.02), tortuosity (P < 0.04), and proximity to a bifurcation (P = 0.03), particularly in left coronary artery cases. X-ray dose, contrast agent volume, and procedure duration were not significantly different. Conclusions: Compared with conventional CA, RoCA augments quantitative lesion assessment, enhances confidence in the assessment of coronary artery disease and the precise details of the proposed procedure, but does not affect X-ray dose, contrast agent volume, or procedure duration. © 2015 Wiley Periodicals, Inc

    Mean flow and spiral defect chaos in Rayleigh-Benard convection

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    We describe a numerical procedure to construct a modified velocity field that does not have any mean flow. Using this procedure, we present two results. Firstly, we show that, in the absence of mean flow, spiral defect chaos collapses to a stationary pattern comprising textures of stripes with angular bends. The quenched patterns are characterized by mean wavenumbers that approach those uniquely selected by focus-type singularities, which, in the absence of mean flow, lie at the zig-zag instability boundary. The quenched patterns also have larger correlation lengths and are comprised of rolls with less curvature. Secondly, we describe how mean flow can contribute to the commonly observed phenomenon of rolls terminating perpendicularly into lateral walls. We show that, in the absence of mean flow, rolls begin to terminate into lateral walls at an oblique angle. This obliqueness increases with Rayleigh number.Comment: 14 pages, 19 figure

    Cross-Newell equations for hexagons and triangles

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    The Cross-Newell equations for hexagons and triangles are derived for general real gradient systems, and are found to be in flux-divergence form. Specific examples of complex governing equations that give rise to hexagons and triangles and which have Lyapunov functionals are also considered, and explicit forms of the Cross-Newell equations are found in these cases. The general nongradient case is also discussed; in contrast with the gradient case, the equations are not flux-divergent. In all cases, the phase stability boundaries and modes of instability for general distorted hexagons and triangles can be recovered from the Cross-Newell equations.Comment: 24 pages, 1 figur

    Cold Feedback in Cooling-Flow Galaxy Clusters

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    We put forward an alternative view to the Bondi-driven feedback between heating and cooling of the intra-cluster medium (ICM) in cooling flow galaxies and clusters. We adopt the popular view that the heating is due to an active galactic nucleus (AGN), i.e. a central black hole accreting mass and launching jets and/or winds. We propose that the feedback occurs with the entire cool inner region (5-30 kpc). A moderate cooling flow does exist here, and non-linear over-dense blobs of gas cool fast and are removed from the ICM before experiencing the next major AGN heating event. Some of these blobs may not accrete on the central black hole, but may form stars and cold molecular clouds. We discuss the conditions under which the dense blobs may cool to low temperatures and feed the black hole.Comment: 6 pages, no figures, to appear in the Proceedings of "Heating vs. Cooling in Galaxies and Clusters of Galaxies", August 2006, Garching (Germany
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