231 research outputs found

    Evaluating the Epidemiology and Management of Bovine Congestive Heart Failure

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    A form of congestive heart failure is increasingly reported as a cause of death in feedlot cattle located at moderate altitude (≤ 1524 m.). Significant knowledge gaps exist in the epidemiology and management of this form of bovine congestive heart failure (BCHF) regarding frequency and timing of BCHF cases and ways in which beef cattle producers and veterinarians can mitigate this condition. These knowledge gaps present major barriers to understanding the mechanism of BCHF and mitigating the consequences of BCHF. The purpose of this thesis is to summarize current knowledge about BCHF, define gaps in knowledge for which more research is needed, formulate hypotheses regarding the knowledge gaps, and discuss two studies designed to test those hypotheses related to the emergence of BCHF. The first study presented is designed to estimate the frequency and timing of BCHF case development. The second study was completed to evaluate the effect of moving two bulls affected by pulmonary arterial hypertension from their ranch of origin to lower elevation as a possible management strategy for mitigation of pulmonary arterial hypertension. Results presented in this thesis provide evidence that the frequency of BCHF cases has increased over the course of six years in the feedlot studied and changing the environment of animals affected by pulmonary arterial hypertension by moving them to lower altitude can lead to a decrease in pulmonary arterial pressure. This thesis will interpret the results of both studies to highlight how these data can aid in understanding the underlying mechanism of BCHF. Advisor: Brian L. Vander Le

    Evaluating the Epidemiology and Management of Bovine Congestive Heart Failure

    Get PDF
    A form of congestive heart failure is increasingly reported as a cause of death in feedlot cattle located at moderate altitude (≤ 1524 m.). Significant knowledge gaps exist in the epidemiology and management of this form of bovine congestive heart failure (BCHF) regarding frequency and timing of BCHF cases and ways in which beef cattle producers and veterinarians can mitigate this condition. These knowledge gaps present major barriers to understanding the mechanism of BCHF and mitigating the consequences of BCHF. The purpose of this thesis is to summarize current knowledge about BCHF, define gaps in knowledge for which more research is needed, formulate hypotheses regarding the knowledge gaps, and discuss two studies designed to test those hypotheses related to the emergence of BCHF. The first study presented is designed to estimate the frequency and timing of BCHF case development. The second study was completed to evaluate the effect of moving two bulls affected by pulmonary arterial hypertension from their ranch of origin to lower elevation as a possible management strategy for mitigation of pulmonary arterial hypertension. Results presented in this thesis provide evidence that the frequency of BCHF cases has increased over the course of six years in the feedlot studied and changing the environment of animals affected by pulmonary arterial hypertension by moving them to lower altitude can lead to a decrease in pulmonary arterial pressure. This thesis will interpret the results of both studies to highlight how these data can aid in understanding the underlying mechanism of BCHF. Advisor: Brian L. Vander Le

    Application of an Optimal Control Allocation Scheme with Structural Load and Aero Heating Feedback for a Morphing Inflatable Aerodynamic Decelerator

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    Precision landing of large payloads on Mars presents a challenge to the Entry, Descent, and Landing (EDL) community. Previous studies indicated that by incorporating the capability for a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) to morph during reentry would result in a more accurate landing footprint by allowing modulation of the lift- to-drag (L/D) vector directly instead of through bank angle control. However, morphing the HIAD shape for trajectory control may expose the HIAD to potential structural loads or aero heating concerns. In this study, the application of an optimal control allocation (OCA) technique was investigated that would to enable the morphing HIAD to maximize trajectory control capabilities while simultaneously keeping the structural loads and aero heating below some thresholds. This concept was demonstrated in a 3 degree-of-freedom (DOF) EDL simulation and provides basis for future research

    A Mismatch in the Ultraviolet Spectra between Low-Redshift and Intermediate-Redshift Type Ia Supernovae as a Possible Systematic Uncertainty for Supernova Cosmology

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    We present Keck high-quality rest-frame ultraviolet (UV) through optical spectra of 21 Type Ia supernovae (SNe Ia) in the redshift range 0.11 < z < 0.37 and a mean redshift of 0.22 that were discovered during the Sloan Digital Sky Survey-II (SDSS-II) SN Survey. Using the broad-band photometry of the SDSS survey, we are able to reconstruct the SN host-galaxy spectral energy distributions (SEDs), allowing for a correction for the host-galaxy contamination in the SN Ia spectra. Comparison of composite spectra constructed from a subsample of 17 high-quality spectra to those created from a low-redshift sample with otherwise similar properties shows that the Keck/SDSS SNe Ia have, on average, extremely similar rest-frame optical spectra but show a UV flux excess. This observation is confirmed by comparing synthesized broad-band colors of the individual spectra, showing a difference in mean colors at the 2.4 - 4.4 sigma level for various UV colors. We further see a slight difference in the UV spectral shape between SNe with low-mass and high-mass host galaxies. Additionally, we detect a relationship between the flux ratio at 2770 and 2900 A and peak luminosity that differs from that observed at low redshift. We find that changing the UV SED of an SN Ia within the observed dispersion can change the inferred distance moduli by ~0.1 mag. This effect only occurs when the data probe the rest-frame UV. We suggest that this discrepancy could be due to differences in the host-galaxy population of the two SN samples or to small-sample statistics.Comment: 28 pages, 21 figures, accepted by AJ, spectra are available at http://www.cfa.harvard.edu/~rfoley/data

    Philosophical Perspectives on Engineering and Technology Literacy, I

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    The belief that engineering and technology are beneficial to all and can improve human lives has inspired the tireless endeavors of many creative individuals throughout history. Engineers and technologists have generally believed that their actions and designs need to be scientifically justified and logically dependable. In addition, due to the pragmatic nature of the field there is also an emphasis on systematic approaches and defining standard practices in engineering. Such a positivist approach is seen in all aspects of engineering and technological ventures. Consequently, such an approach exists in most engineering educators’ perspectives and belief structures regarding the contents of the curricular, student training, and the overall goal of engineering and technological education.https://lib.dr.iastate.edu/ece_books/1000/thumbnail.jp

    Photometric Supernova Cosmology with BEAMS and SDSS-II

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    Supernova cosmology without spectroscopic confirmation is an exciting new frontier which we address here with the Bayesian Estimation Applied to Multiple Species (BEAMS) algorithm and the full three years of data from the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN). BEAMS is a Bayesian framework for using data from multiple species in statistical inference when one has the probability that each data point belongs to a given species, corresponding in this context to different types of supernovae with their probabilities derived from their multi-band lightcurves. We run the BEAMS algorithm on both Gaussian and more realistic SNANA simulations with of order 10^4 supernovae, testing the algorithm against various pitfalls one might expect in the new and somewhat uncharted territory of photometric supernova cosmology. We compare the performance of BEAMS to that of both mock spectroscopic surveys and photometric samples which have been cut using typical selection criteria. The latter typically are either biased due to contamination or have significantly larger contours in the cosmological parameters due to small data-sets. We then apply BEAMS to the 792 SDSS-II photometric supernovae with host spectroscopic redshifts. In this case, BEAMS reduces the area of the (\Omega_m,\Omega_\Lambda) contours by a factor of three relative to the case where only spectroscopically confirmed data are used (297 supernovae). In the case of flatness, the constraints obtained on the matter density applying BEAMS to the photometric SDSS-II data are \Omega_m(BEAMS)=0.194\pm0.07. This illustrates the potential power of BEAMS for future large photometric supernova surveys such as LSST.Comment: 25 pages, 15 figures, submitted to Ap

    Experiencing Grace: A Review of the Empirical Literature

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    Positive psychologists have used science to understand many virtues but have only just started to study grace, recently defined as ‘ . . . the gift of acceptance given unconditionally and voluntarily to an undeserving person by an unobligated giver’. The purpose of the current article is to provide a systematic review of all empirical studies (published and unpublished) on grace. Broadly, the empirical study of grace has focused on what people believe and how people experience both divine and human grace. Additionally, empirical attention has shifted to explore outcomes of grace-based interventions (e.g., congregation-wide interventions, marital interventions). In general, beliefs and experiences of grace were associated with (a) positive mental health outcomes, (b) religiosity, (c) virtue development, and (d) interpersonal functioning. Human grace has not been extensively explored and divine grace has been studied mostly among Christians; future studies should address these limitations and explore causal relationships

    Dynamical System Approach to Cosmological Models with a Varying Speed of Light

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    Methods of dynamical systems have been used to study homogeneous and isotropic cosmological models with a varying speed of light (VSL). We propose two methods of reduction of dynamics to the form of planar Hamiltonian dynamical systems for models with a time dependent equation of state. The solutions are analyzed on two-dimensional phase space in the variables (x,x˙)(x, \dot{x}) where xx is a function of a scale factor aa. Then we show how the horizon problem may be solved on some evolutional paths. It is shown that the models with negative curvature overcome the horizon and flatness problems. The presented method of reduction can be adopted to the analysis of dynamics of the universe with the general form of the equation of state p=γ(a)ϵp=\gamma(a)\epsilon. This is demonstrated using as an example the dynamics of VSL models filled with a non-interacting fluid. We demonstrate a new type of evolution near the initial singularity caused by a varying speed of light. The singularity-free oscillating universes are also admitted for positive cosmological constant. We consider a quantum VSL FRW closed model with radiation and show that the highest tunnelling rate occurs for a constant velocity of light if c(a)anc(a) \propto a^n and 1<n0-1 < n \le 0. It is also proved that the considered class of models is structurally unstable for the case of n<0n < 0.Comment: 18 pages, 5 figures, RevTeX4; final version to appear in PR

    Controlled aqueous polymerization of acrylamides and acrylates and “in situ” depolymerization in the presence of dissolved CO2

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    Aqueous copper-mediated radical polymerization of acrylamides and acrylates in carbonated water resulted in high monomer conversions (t t > 10 min). The regenerated monomer was characterized and repolymerized following deoxygenation of the resulting solutions to reyield polymers in high conversions that exhibit low dispersities

    The Grizzly, October 5, 1979

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    Senior Fired From Snack Shop • Parking Regulations Explained • Bio Club Explores Pine Barrens • Craft Discusses Plans • Letters to the Editor: Faculty responds to censoring article • ERA Hits Dishroom • Dave Rebuck: A Close-up • The Best Of The Seventies • Music News • Joe Jackson - Moon Marten and The Ravens • Talking Heads - Fear Of Music • Fans Catch Fever At Bee Gees Concert • USGA Notes • Renovation Underway • Richter Accepts Advance Ursinus Donation • Bears\u27 Booters On Again • Fearless Friday Forecast • Victory Sparks Women\u27s Volleyball • Hard Work Pays Off For V & JV Hockey • Hockey\u27s Third Team Has Inconsistent Starthttps://digitalcommons.ursinus.edu/grizzlynews/1022/thumbnail.jp
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