575 research outputs found

    Synchronization of ovulation in beef herds: improved conception rate after and interrupted course of progesterone administration

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    Die bronstigheidsiklusse van vleisraskoeie en/of verse is in ses kuddes deur binnespierse progesterooninspuitings gesinkroniseer. Om die koeie wat met die aanvang van die behandeling in die laat fase van 'n siklus verkeer en wat dikwels gedegenereerde ova na sinkronisasie vrystel uit te skakel is die behandeling in twee fases verdeel. Eers is vier 48-uurlikse inspuitings van 50 mg progesteroon in propileenglikol toegedien, dan is 'n periode van 8 dae oorgeslaan voordat die tweede reeks van ses 48-uurlikse progesterooninspuitings hervat is. Met hierdie metode is uiters bevredigende resultate met inseminasie tydens die eerste gesinkroniseerde bronstigheid verkry in 4 uit die 6 kuddes. Konsepsiesyfers wat tussen 69 en 86 % gevarieer het is behaal wat goed vergelyk met die gemiddelde van ongeveer 70%vir eerste inseminasie sonder sinkronisasie en 'n groot verbetering is op die gemiddelde besettingsyfer van 47%(36 tot 58%)wat voorheen na progesterooninspuitings behaal is.The oestrous cycles of cows and/or heifers were synchronized in six herds by the intramuscular administration of progesterone. In order to exclude those cows that were in the latter third of their cycles at the onset of treatment, the herds were first presynchronized by four 48-hourly injections of 50 mg of progesterone in propylene glycol and after an interval of eight days, treatment was resumed by giving them 6 more such 48-hourly injections. Conception figures varying from 69 to 86 % were attained in 4 of the 6 trials during the synchronized oestrus. These compare favourably with normal first insemination figures uncomplicated by synchronization and represent a marked improvement onthe average figure of 47% (36 to 58%) previously experienced after synchronization with progesterone

    A study of the stress wave factor technique for evaluation of composite materials

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    The acousto-ultrasonic approach for nondestructive evaluation provides a measurement procedure for quantifying the integrated effect of globally distributed damage characteristic of fiber reinforced composite materials. The evaluation procedure provides a stress wave factor that correlates closely with several material performance parameters. The procedure was investigated for a variety of materials including advanced composites, hybrid structure bonds, adhesive bonds, wood products, and wire rope. The research program focused primarily on development of fundamental understanding and applications advancements of acousto-ultrasonics for materials characterization. This involves characterization of materials for which detection, location, and identification of imperfections cannot at present be analyzed satisfactorily with mechanical performance prediction models. In addition to presenting definitive studies on application potentials, the understanding of the acousto-ultrasonic method as applied to advanced composites is reviewed

    Low-noise amplifier cryogenic testbed validation in a TaaS (Testing-as-a-Service) framework

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    As quantum computers based on superconducting qubit processors scale, cryogenic microwave components in the qubit control and readout chain must be appropriately tested and qualified to ensure consistent and high-fidelity quantum computation. However, the intersection of superconducting cryogenics and microwave electronics is a new domain with limited technical and commercial expertise. In this paper we validate a TaaS (testing-as-a-service) framework using an organizational workgroup model that consists of (1) a commercial Test House, (2) standard temperature Component Manufacturer, (3) Academic Partner, and (4) System Integrator to demonstrate a scalable model for the qualification of cryogenic microwave components. The goal of this model is to secure the supply chain and support the rapid growth of Quantum Computing (QC) technologies. The component test vehicle presented in this paper is a low-noise amplifier (LNA) which is a crucial component in the cryogenic chain to ensure adequate signal-to-noise of the qubit readout. We devise standard test metrics and protocols by which LNA performance is measured, including key parameters such as gain and flatness, reflection and isolation, operating bandwidth, and noise figure. We present details of the cryogenic testbed customized for LNA qualification, outline test methodologies, and present a suite of standard processes that are used to systematize data collation and reporting. The testbed is validated by reproducing parameters of a pre-characterized LNA. Its value is demonstrated by characterizing a proof-of-concept cryogenic LNA prototype. Finally, we describe the extension of our TaaS framework toward testing at scale for various active and passive cryogenic components used in QC

    Thomson scattering from a shock front

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    We have obtained a Thomson scattering spectrum in the collective regime by scattering a probe beam from a shock front, in an experiment conducted at the Omega laser at the Laboratory for Laser Energetics. The probe beam was created by frequency converting a beamline at Omega to a 2 ns2ns pulse of 0.263 Όm0.263ÎŒm light, focused with a dedicated optical focusing system. The diagnostic system included collecting optics, spectrometer, and streak camera, with a scattering angle of 101°. The target included a primary shock tube, a 20-ÎŒm20-ÎŒm-thick beryllium drive disk, 0.3-ÎŒm0.3-ÎŒm-thick polyimide windows mounted on a secondary tube, and a gas fill tube. Detected acoustic waves propagated parallel to the target axis. Ten laser beams irradiated the beryllium disk with 0.351 Όm0.351ÎŒm light at 5×1014 W/cm25×1014W∕cm2 for 1 ns1ns starting at toto, driving a strong shock through argon gas at ρo = 1 mg/ccρo=1mg∕cc. The 200 J200J probe beam fired at t = 19 nst=19ns for 2 ns2ns, and at t = 20.1 nst=20.1ns a 0.3 ns0.3ns signal was detected. We attribute this signal to scattering from the shocked argon, before the density increased above critical due to radiative collapse.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87893/2/10E504_1.pd

    Dual, orthogonal, backlit pinhole radiography in OMEGA experiments

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    Backlit pinhole radiography used with ungated film as a detector creates x-ray radiographs with increased resolution and contrast. Current hydrodynamics experiments on the OMEGA Laser use a three-dimensional sinusoidal pattern as a seed perturbation for the study of instabilities. The structure of this perturbation makes it highly desirable to obtain two simultaneous orthogonal backlighting views. We accomplished this using two backlit pinholes each mounted 12 mm12mm from the target. The pinholes, of varying size and shape, were centered on 5 mm5mm square foils of 50 Όm50ÎŒm thick Ta. The backlighting is by KK-alpha emission from a 500 Όm500ÎŒm square Ti or Sc foil mounted 500 Όm500ÎŒm from the Ta on a plastic substrate. Four laser beams overfill the metal foil, so that the expanding plastic provides radial tamping of the expanding metal plasma. The resulting x-rays pass through the target onto (ungated) direct exposure film (DEF). Interference between the two views is reduced by using a nose cone in front of the DEF, typically with a 9 mm9mm Ta aperture and with magnets to deflect electrons. Comparison of varying types of pinholes and film exposures will be presented from recent experiments as well as an analysis of the background noise created using this experimental technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87894/2/10E327_1.pd

    The development of social preferences

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    This paper examines how social preferences develop with age. This is done using a range of mini-dictator games from which we classify 665 subjects into a variety of behavioural types. We expand on previous developmental studies of pro-sociality and parochialism by analysing individuals aged 9–67, and by employing a cross country study where participants from Spain interact with participants from different ethnic groups (Arab, East Asian, Black and White) belonging to different countries (Morocco, China, Senegal and Spain). We identify a ‘U-shaped’ relationship between age and egalitarianism that had previously gone unnoticed, and appeared linear. An inverse “U-shaped” relationship is found to be true for altruism. A gender differential is found to emerge in teenage years, with females becoming less altruistic but more egalitarian than males. In contrast to the majority of previous economic studies of the development of social preferences, we report evidence of increased altruism, and decreased egalitarianism and spite expressed towards black individuals from Senegal

    The Development of Social Preferences

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    This paper examines how social preferences develop with age. This is done using a range of mini-dictator games from which we classify 665 subjects into a variety of behavioural types. We expand on previous developmental studies of pro-sociality and parochialism by analysing individuals aged 9–67, and by employing a cross country study where participants from Spain interact with participants from different ethnic groups (Arab, East Asian, Black and White) belonging to different countries (Morocco, China, Senegal and Spain). We identify a ‘U-shaped’ relationship between age and egalitarianism that had previously gone unnoticed, and appeared linear. An inverse “U-shaped” relationship is found to be true for altruism. A gender differential is found to emerge in teenage years, with females becoming less altruistic but more egalitarian than males. In contrast to the majority of previous economic studies of the development of social preferences, we report evidence of increased altruism, and decreased egalitarianism and spite expressed towards black individuals from Senegal
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