3,373 research outputs found

    CONTRACT FINISHING FOR NEW ENTRANTS IN PORK PRODUCTION

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    The pork production industry is a far different industry today than it was fifty, twenty, or even five years ago. On diversified Midwestern farms during the mid-to-late 20th century, the swine enterprise was labeled "the mortgage lifter". The hogs added value to home-produced feedstuffs such as corn and increased the income from a given acreage base. As farm mechanization and technology rapidly developed, farms became larger and less diversified as livestock disappeared from many farmsteads. In this paper, we address the question whether swine units can be introduced to non-livestock farms via a coordinated agreement for the grower-finisher phase and make these farms more profitable. To do this, we first describe some of the changes that have taken place in the pork industry. Second, production contracts and grower payments are introduced. Next, we move on to issues of manure management and the value of manure to non-livestock farms. Finally, in the Appendix, financial analyses for sample contract finishing contracts are laid out to help farmers determine if contract finishing could benefit their farming operations.Livestock Production/Industries,

    Familial hemiplegic migraine with cerebellar ataxia and paroxysmal psychosis

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    Familial hemiplegic migraine is a rare autosomal dominant disorder associated with stereotypic neurologic au ra phenomena including hemiparesis, So far two chromosomal loci have been identified. Families linked to the chromosome 19 locus display missense mutations within the CACNL1A4 gene. Here we report on a family with familial hemiplegic migraine and cerebellar ataxia with recurrent episodes of acute paranoid psychosis with anxiety and visual hallucinations associated with migraine attacks. Based on the clinical and haplotype evidence indicating linkage to chromosome 19 in this family, we hypothesize that a dysfunction of the mutated calcium channel may be involved not only in the development of hemiplegic migraine but also in the acute psychotic episodes observed in these patients

    Anomalous dynamics of cell migration

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    Cell movement, for example during embryogenesis or tumor metastasis, is a complex dynamical process resulting from an intricate interplay of multiple components of the cellular migration machinery. At first sight, the paths of migrating cells resemble those of thermally driven Brownian particles. However, cell migration is an active biological process putting a characterization in terms of normal Brownian motion into question. By analyzing the trajectories of wildtype and mutated epithelial (MDCK-F) cells we show experimentally that anomalous dynamics characterizes cell migration. A superdiffusive increase of the mean squared displacement, non-Gaussian spatial probability distributions, and power-law decays of the velocity autocorrelations are the basis for this interpretation. Almost all results can be explained with a fractional Klein- Kramers equation allowing the quantitative classification of cell migration by a few parameters. Thereby it discloses the influence and relative importance of individual components of the cellular migration apparatus to the behavior of the cell as a whole.Comment: 20 pages, 3 figures, 1 tabl

    Measurement of energy eigenstates by a slow detector

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    We propose a method for a weak continuous measurement of the energy eigenstates of a fast quantum system by means of a "slow" detector. Such a detector is only sensitive to slowly-changing variables, e. g. energy, while its back-action can be limited solely to decoherence of the eigenstate superpositions. We apply this scheme to the problem of detection of quantum jumps between energy eigenstates in a harmonic oscillator.Comment: 4 page

    The role of Nogo-A in axonal plasticity, regrowth and repair

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    Axonal damage leads to permanent deficits in the adult central nervous system (CNS) not only because of the weak intrinsic ability of adult neurons to activate their growth program but importantly also because of the presence of specific growth inhibitors in the CNS tissue and the environment of the damaged axons. The well-studied myelin-derived protein Nogo-A is involved in various cellular and molecular events contributing to the failure of CNS axons to regrow and reconnect after transection. Recent studies have shown that, by acting in a negative way on the cytoskeleton and on the growth program of axotomized neurons, Nogo-A exerts fast and chronic inhibitory effects on neurite outgrowth. On the other hand, the blockade of Nogo-A results in a marked enhancement of compensatory and regenerative axonal extension in vivo; this enhancement is often paralleled by significant functional recovery, for example, of locomotion or skilled forelimb reaching after spinal cord or stroke lesions in rats and monkeys. Surprisingly, the blockade of Nogo-A or its receptor NgR in the hippocampus has recently been demonstrated to enhance long-term potentiation. A role of Nogo-A in synaptic plasticity/stability might therefore represent an additional, new and important aspect of CNS circuit remodeling. Function-blocking anti-Nogo-A antibodies are currently being tested in a clinical trial for improved outcome after spinal cord injur

    A Radon diffraction theorem for plane wave ultrasound imaging

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    The rising demand on high frame rate ultrasound imaging applications necessitates the development of fast algorithms for plane wave image reconstruction. We introduce a new class of plane wave reconstructions that relies on a relation between receive data and image data in the Radon domain. This relation is derived for arbitrary dimensions and validated on multiple two-dimensional plane wave data sets. We further present a mathematical relation between conventional delay-and-sum and Fourier domain reconstruction methods and the method proposed. Our analysis shows that they all rely on the same physical model with slight variations in certain filtering steps and, therefore, the new Radon domain reconstruction yields similar results as other methods in terms of image quality. However, we show that our method offers a huge potential to improve computation time by reducing the number of applied projections and to improve image quality by introducing nonlinear operations in the Radon domain, e.g., for edge enhancement. As the Radon transform retains both angular and temporal information, the relation also provides new insights on the fundamentals of plane wave imaging that can be leveraged for optimizing acquisition schemes or for developing novel compounding strategies in the future

    2-Undecanone : a new attractant for anthropophilic mosquitoes

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    Stechmücken der Art Stegomyia aegypti (ehemals Aedes aegypti, REINERT et al. 2004) sind die wichtigsten Überträger von Gelbfieber- und Dengueviren. Diverse Arten der Gattung Anopheles verbreiten die Erreger der Malaria. Bei Versuchen, Malaria, Gelbfieber und Dengue einzudämmen, wurden in den letzten Jahrzehnten wiederholt Kampagnen gegen Stechmücken geführt. Dabei wurden Insektizide vielfach flächendeckend ausgebracht. Dies führte kurzfristig zu geringeren Mückendichten, allerdings entwickelten sich auch vielerorts gegen diese Gifte resistente Mückenpopulationen. Anstelle des flächendeckenden Gifteinsatzes wird heute versucht, die Insektizide örtlich und zeitlich effektiv einzusetzen, um so die Gefahr weiterer Resistenzbildung zu minimieren und sowohl die Kosten als auch die Belastung für Umwelt und Bevölkerung möglichst gering zu halten. Um Insektizide zur richtigen Zeit gezielt ausbringen zu können, ist ein Monitoring der Mücken erforderlich. Mückenfallen, die durch optische Effekte und Duftstoffe gezielt anthropophile Stechmückenarten anlocken, sind für ein derartiges Bestandsmonitoring besonders geeignet. Auf der Suche nach attraktiven Duftstoffen, welche die Effektivität solcher Fallen erhöhen, wurde unter anderem auch 2-Undecanon getestet. In Verhaltensversuchen mit den anthropophilen Mückenarten Stegomyia aegypti und Anopheles stephensi konnte die Attraktivität dieser Substanz sowohl als Einzelreiz als auch in Kombination mit anderen Attraktanzien gezeigt und quantifiziert werden.The attractiveness of 2-undecanone to host-seeking female Stegomyia aegpyti (former Aedes aegypti) and female Anopheles stephensi (Diptera: Culicidae) mosquitoes was tested in a Y-tube bioassay under laboratory conditions. -Undecanone alone in a concentration of 40 ppm was significantly more attractive to S. aegypti mosquitoes than pure air. In combination with other kairomones such as caproic acid, lactic acid and ammonia doses of 2-undecanone from 4 ppm up to 130 ppm augmented significantly the attractiveness of these kairomones. The synergism of 2-undecanone with other attractants is comparable to that one described for lactic acid. The combination of 2-undecanone with lactic acid, however, was more attractive than the two compounds as single stimuli. Interestingly 2-undecanone is neither known as an human skin compound nor as a volatile in human breath. First field experiments near Regensburg in Germany with BG-Sentinel® mosquito traps could not confirm the attractive effect of 2-undecanone (ROSE et al. 2006) for Culex species. A possible explanation could be that the tested dose of 2-undecanone was not in the optimum range or that the studied species do not respond to this compound

    Chern classes of linear submanifolds with application to spaces of k-differentials and ball quotients

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    We provide formulas for the Chern classes of linear submanifolds of the moduli spaces of Abelian differentials and hence for their Euler characteristic. This includes as special case the moduli spaces of k-differentials, for which we set up the full intersection theory package and implement it in the sage-program diffstrata. As an application, we give an algebraic proof of the theorems of Deligne-Mostow and Thurston that suitable compactifications of moduli spaces of k-differentials on the 5-punctured projective line with weights satisfying the INT-condition are quotients of the complex two-ball
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