1,024 research outputs found

    Chaotic enhancement of dark matter density in binary systems

    Full text link
    We study the capture of galactic dark matter particles (DMP) in two-body and few-body systems with a symplectic map description. This approach allows modeling the scattering of 101610^{16} DMPs after following the time evolution of the captured particle on about 10910^9 orbital periods of the binary system. We obtain the DMP density distribution inside such systems and determine the enhancement factor of their density in a center vicinity compared to its galactic value as a function of the mass ratio of the bodies and the ratio of the body velocity to the velocity of the galactic DMP wind. We find that the enhancement factor can be on the order of tens of thousands.Comment: 6 pages, 9 figure

    Statistical Analysis of Instantaneous Velocities in Turbulent Flow of Dilute Viscoelastic Solutions

    Get PDF
    An experimental study, based on streak photograph determination of instantaneous velocities, was directed at determining the structure of turbulence within the boundary layer and core regions of circular pipes. The measurements lend support to the ejection phenomenon as the mechanism controlling drag reduction. A correlation factor, defined as the ratio of the observed number of positive instantaneous radial velocities, to the observed number of negative instantaneous radial velocities, suggests acceleration in the radial direction as the elements of fluid move through the sublayer. The correlation factor also provides information about the thickening of the boundary layer for drag reducers relative to the Newtonian case. Radial turbulent intensity data for 0.01% aqueous solutions of Separan AP-30 were found to be markedly lower, at all radial positions, than the intensities for Newtonian fluids. The lowering of the radial intensities being ordered according to the amount of drag reduction

    V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula

    Full text link
    In late 2003, the young eruptive variable star V1647 Orionis optically brightened by over 5 magnitudes, stayed bright for around 26 months, and then decline to its pre-outburst level. In August 2008 the star was reported to have unexpectedly brightened yet again and we herein present the first detailed observations of this new outburst. Photometrically, the star is now as bright as it ever was following the 2003 eruption. Spectroscopically, a pronounced P Cygni profile is again seen in Halpha with an absorption trough extending to -700 km/s. In the near-infrared, the spectrum now possesses very weak CO overtone bandhead absorption in contrast to the strong bandhead emission seen soon after the 2003 event. Water vapor absorption is also much stronger than previously seen. We discuss the current outburst below and relate it to the earlier event.Comment: 6 pages, 3 figure

    Survey of Dairy Management Practices on One Hundred Thirteen North Central and Northeastern United States Dairies

    Get PDF
    The objective was to conduct a broad survey of dairy management practices that have an effect on animal well-being. Dairies were visited during the fall and winter of 2005 and 2006 in Wisconsin, Minnesota, Indiana, Iowa, and New York. Data were collected on 113 dairies on colostrum feeding, dehorning, tail-docking, euthanasia methods, producer statements about welfare, use of specialized calf-raising farms (custom), level of satisfaction with calf-raising by producers, and cow behavior. Calves were raised by the owner on 50.4% of dairies; 30.1% were raised on custom farms during the milk-feeding period, 18.6% were custom raised after weaning, and 1% sold calves with the option to buy them back as first-lactation heifers. A total of 51.8% of producers were very satisfied with their current calf-raising methods. Three feedings of colostrum were fed to the calves on 23.9% of dairies, 2 feedings on 39.8% of farms, 1 feeding on 31.0% of farms, and colostrum replacement products were fed on 5.3% of farms. Many farms (61.9%) provided 3.8 L at first feeding. Calves were dehorned at different ages by various methods. By 8 wk, 34.5% of calves were dehorned. By 12 wk, 78.8% of calves were dehorned. The majority of calves were dehorned by hot iron (67.3%). The remainder were dehorned by gouging (8.8%), paste (9.7%), saw (3.5%), or unknown by calf owner (10.6%). Anesthetic use was reported by 12.4% of dairy owners and analgesia use by 1.8%. Tail-docking was observed on 82.3% of dairies. The most common reported docking time was pre- or postcalving (35.2%). The second most commonly reported time was d 1 (15.4%). Rubber band was the most common method (92.5%), followed by amputation (7.5%). Three dairies amputated precalving, 1 at 2 mo and 3 at d 1 or 2. Cow hygiene was the most common reason given to dock (73.5%), followed by parlor worker comfort (17.4%) and udder health (1.0%). Producers reported 2.0% of cows obviously lame. Gun was the preferred euthanasia method (85.7%), followed by i.v. euthanasia (8.0%), live pick-up (1.8%), and nondisclosure (3.5%). Most producers (77.9%) stated that cows were in an improved environment as compared with 20 yr ago, whereas 8.0% stated conditions were worse, and 14.2% were undecided. Dairies with higher percentages of cows that either approached or touched the observer had lower somatic cell counts. The survey results showed management practices that were important for animal welfare

    When care is defined by science: exploring veterinary medicine through a more-than-human geography of empathy

    Get PDF
    Veterinary medicine is the profession that is widely perceived as being at the forefront of animal care in the United Kingdom (UK). It is a form of care that is multi‐spatial and multi‐species: veterinary surgeons are involved in broad debates about animal welfare while also intimately caring for our pet companions. In order to regulate the profession, the Royal College of Veterinary Surgeons provides the Code of Professional Conduct (CPC) as the principal ethical framework that must be adhered to by all UK veterinary surgeons. The main aim of the CPC claims to ensure that the animal is, first and foremost, the primary consideration in veterinary medicine. By exploring the CPC in relation with animal geographies, emotional geographies and science and technology studies, this paper shows how the CPC remains anthropocentric and focused on a rational scientism that limits affective attunement with non‐human animals and distrusts the role of emotion and affect in veterinary medicine. These ethical‐spatial implications are then shown to extend beyond the CPC and into the conceptual terrain of ethics teaching in undergraduate veterinary education. As a way through this ethical tangle, a more‐than‐human geography of empathy is proposed. This notion takes the site of empathy as its geographical focus and suggests that a more critical, situated and holistic understanding of empathy might allow for a more thorough consideration of the tensions between human and animal and science and emotion in veterinary medicine and human geography more widely

    Effect of stall base type on herd health, costs, and producer satisfaction

    Get PDF
    The objective of this field study was to compare effect of stall base on herd health, stall maintenance, bedding cost, and producer satisfaction. Ninety-one dairies visited during a 4-mo period starting October 14, 2005 included 33 rubber-filled mattress (RFM), 27 sand, and 31 waterbed (WB) dairies. In this study, percent culled was higher for RFM (P = 0.001) and sand (P = 0.06) than WB stall base dairies. Percent of cows in fourth lactation or greater was higher on WB than either RFM (P = 0.01) or sand (P = 0.02) dairies. There was no difference between base types for production or somatic cell count. Bedding cost per bed per week was WB (0.73),RFM(0.73), RFM (0.89), and sand ($0.97). Sand beds were bedded less frequently (P = 0.01). Comparisons between RFM and sand indicate higher satisfaction for RFM regarding manure management (P \u3c 0.0001) and higher satisfaction with sand for cow comfort (P \u3c 0.0001). Producers with WB were more satisfied with base life (P \u3c 0.000 1) and cow comfort (P \u3c 0.000 1) than those with RFM. Producers with WB were more satisfied with cow longevity (P \u3c 0.0001) as compared to RFM. Length of sand stall was correlated with longevity (0.56, P = 0.01) while percent of mature cows was greater on dairies that provided WBs (P = 0.02). This data indicates that WB may be a viable option for cows and producers, when good quality sand is unavailable or handling sand-laden manure is not feasible

    Effect of stall base type on herd health, costs, and producer satisfaction

    Get PDF
    The objective of this field study was to compare effect of stall base on herd health, stall maintenance, bedding cost, and producer satisfaction. Ninety-one dairies visited during a 4-mo period starting October 14, 2005 included 33 rubber-filled mattress (RFM), 27 sand, and 31 waterbed (WB) dairies. In this study, percent culled was higher for RFM (P = 0.001) and sand (P = 0.06) than WB stall base dairies. Percent of cows in fourth lactation or greater was higher on WB than either RFM (P = 0.01) or sand (P = 0.02) dairies. There was no difference between base types for production or somatic cell count. Bedding cost per bed per week was WB (0.73),RFM(0.73), RFM (0.89), and sand ($0.97). Sand beds were bedded less frequently (P = 0.01). Comparisons between RFM and sand indicate higher satisfaction for RFM regarding manure management (P \u3c 0.0001) and higher satisfaction with sand for cow comfort (P \u3c 0.0001). Producers with WB were more satisfied with base life (P \u3c 0.000 1) and cow comfort (P \u3c 0.000 1) than those with RFM. Producers with WB were more satisfied with cow longevity (P \u3c 0.0001) as compared to RFM. Length of sand stall was correlated with longevity (0.56, P = 0.01) while percent of mature cows was greater on dairies that provided WBs (P = 0.02). This data indicates that WB may be a viable option for cows and producers, when good quality sand is unavailable or handling sand-laden manure is not feasible

    Influence of Free-Stall Base on Tarsal Joint Lesions and Hygiene in Dairy Cows

    Get PDF
    The objective was to quantify the incidence of tarsal lesions and level of hygiene by stall bed type. Cows were scored on 100 dairies from Wisconsin, Minnesota, Indiana, Iowa, and New York in the fall and winter. Thirty-eight dairies used rubber-filled mattresses (RFM), 27 had sand beds, 29 had waterbeds, and 6 used compost packs (CPk). Stocking density, stall dimensions, bedding amount, bedding frequency, and type of bedding were recorded. One pen of early-lactation multiparous cows on each dairy was scored based on injury of the tarsal joints at the lateral and medial surfaces and tuber calcis at the dorsal, lateral, and medial surfaces. A tarsal score of 1 represented hair loss, 2 was moderate, and 3 indicated severe swelling. Differences between bed types in the percentages of cows with lesions were tested with one-way ANOVA by lesion severity and incidence, with farm as the experimental unit. Cows on sand beds or waterbeds had fewer lesion scores of 1, 2, and 3 than those on RFM. The percentages of score 1 were 54.6 ± 4.4 (RFM), 22.5 ± 4.7 (sand), and 29.8 ± 4.3 (waterbed), whereas the percentages of score 2 were 14.0 ± 1.4, 2.3 ± 1.5, and 5.0 ± 1.4, and of score 3 were 3.0 ± 0.4, 0.2 ± 0.4, and 0.4 ± 0.4. Cows on CPk had no lesions. Hygiene scores ranged from 1 to 5, with 1 being clean and 5 soiled. The percentages of hygiene score 1 were 0 (compost), 0.4 (RFM), 0.4 (sand), and 0.4 (waterbeds); those with score 2 were 79.0, 84.0 ± 0.01, 73.2 ± 0.01, and 80.4 ± 0.01; with score 3 were 20.3, 15.2 ± 0.01, 23.8 ± 0.01, and 18.6 ± 0.01; with score 4 were 0.8, 0.005 ± 0.001, 0.006 ± 0.001, and 0.025 ± 0.003; and with score 5 was 0 for all bed types. Cows on RFM and waterbeds had improved hygiene compared with cows on sand beds. There was no difference in somatic cell count (SCC) by bed type. The percentage of cows in fourth lactation or greater on waterbeds (19.8 ± 1.8) was greater than those on RFM (13.3 ± 1.6) or on sand (13.5 ± 1.8). The percentage culled was lower for cows on waterbeds than on RFM (22.8 ± 1.5 vs. 29.4 ± 1.4). Score 3 tarsal lesions were correlated (r = 0.60) with SCC. The length of the sand bed was correlated with a greater percentage of mature cows. The SCC was correlated with the percentage of cows reported lame on the day of the visit (r = 0.45) and with neck rail height (r = −0.26). On dairies with RFM, severe lesions (r = 0.60), death losses (r = 0.52), and percentage of the herd reported lame on the day of the visit (r = 0.52) were all correlated with the SCC. Dairies with higher percentages of lesions had higher SCC, death losses, lameness, and culling rates. Adding bedding several times per week may reduce the incidence of lesions
    • 

    corecore