4,644 research outputs found
TSE pathogenesis in cattle and sheep
No full textMany studies have been undertaken in rodents to study the pathogenesis of transmissible spongiform encephalopathies (TSE). Only a few studies have focused on the pathogenesis of bovine spongiform encephalopathy (BSE) and scrapie in their natural hosts. In this review, we summarize the most recent insights into the pathogenesis of BSE and scrapie starting from the initial uptake of TSE agents and crossing of the gut epithelium. Following replication in the gut-associated lymphoid tissues (GALT), TSE agents spread to the enteric nervous system (ENS) of the gut. Infection is then carried through the efferent fibers of the post-ganglionic neurons of the parasympathetic and sympathetic nervous system to the pre-ganglionic neurons in the medulla oblongata of the brain and the thoracic segments of the spinal cord. The differences between the pathogenesis of BSE in cattle and scrapie in sheep are discussed as well as the possible existence of additional pathogenetic routes
Proteins as markers of TSE infection in sheep blood
No full textTransmissible spongiform encephalopathies (TSEs) are a group of fatal infectious
neurodegenerative diseases affecting both humans and agricultural animals. TSE
transmission via blood transfusion has been demonstrated experimentally in rodent,
primate and sheep models. Additionally, in humans, four variant Creutzfeld-Jakob
disease (vCJD) cases have been reported which probably resulted from infected blood
transfusions. Although TSEs can be transmitted via blood transfusion, little is known
about which blood cells are involved in the replication of the TSE agent and how
infectivity is spread throughout the body prior to neuroinvasion. There are no currently
validated diagnostic tests for TSE infection in blood.Detection of PK-resistant PrPSc has been extensively used as a biochemical marker for
TSE infectivity. However, when this project was started it was not known if PKresistant
PrPSc was present in TSE-infected sheep blood in sufficient quantities to
explain the infectivity levels shown by bioassay. Following the development of an
optimised Western blot method, this project has demonstrated that the pattern of protein
detected with novel anti-PrP monoclonal antibodies is very different from the
conventional triple banded pattern of PK-resistant PrPSc. High molecular weight bands
were apparent in phosphotungstic acid (NaPTA) concentrated scrapie-infected and
uninfected blood and may represent a novel form of blood-specific PrP. PK-resistant
PrPSc is not therefore a suitable marker for TSE infection in blood.Other proteins in TSE infected blood were also investigated. Using a proteomics
approach three protein markers, lactate dehydrogenase, elongation factor 1 and annexin
1 had altered expression patterns in scrapie infected blood. These proteins, in addition
to the novel forms of PrP found in blood, may provide new information on the
mechanisms of pathogenesis in scrapie-infected sheep and might prove to be useful
molecular indicators of diagnostic value
On using Directional Information for Parameter Space Decomposition in Ellipse Detection
No full textIn this paper we use the parametric polar representation to extend the application of edge directional information from circle to ellipse extraction. As a result we obtain a mapping which decomposes the parameter space required for ellipse extraction into two independent sub-spaces and one final histogram accumulator. The mapping includes the tangent of the angle of the first and second directional derivatives. These tangents are computed by considering edge direction at two border points. We show that the use of gradient information for parameter space decomposition avoids the intensive point labelling imposed by geometric constraints used by other approaches
Large-scale patterns in turbulent Rayleigh-Bénard convection in very large aspect ratio cells
No full textLarge-scale patterns, which are well-known from the spiral defect chaos regime of thermal convection at Rayleigh numbers Ra 105. They are uncovered when the turbulent fields are averaged in time and turbulent fluctuations are thus removed. We apply the Boussinesq closure to calculate turbulent viscosities and diffusivities, respectively. The resulting turbulent Rayleigh number Ra_, that describes the convection of the mean patterns, is indeed in the spiral defect chaos range. Interestingly, the turbulent Prandtl numbers are smaller than one with 0:2 _ Pr_ _ 0:4 for Prandtl numbers 0:7 _ Pr _ 10. Finally, we demonstrate that these mean flow patterns are robust to an additional finite-amplitude side wall-forcing when the level of turbulent fluctuations in the flow is sufficiently high
Reynolds number effect on 3D turbulent offset jet reattaching to a free surface
No full textExperimental study was carried out to investigate the effect of Reynolds number on 3D offset jet reattaching to above free surface. Sharp edged square nozzle was used to produce the jets, and the measurements were performed at the following six different Reynolds numbers: 2300, 3700, 5100, 7900, 10300 and 11900. Detailed velocity measurements were made in the symmetry plane. From the PIV data, the mean velocity and turbulence statistics were obtained to study the effects of Reynolds number on the salient features of the jet flow. Preliminary results on streamwise mean velocity decay along the nozzle centerline, contours of streamwise mean velocity and Reynolds shear stress are presented herein
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
<i>Entrenchment, wealth, power, and the constitution of democratic societies</i> by Paul Starr
No full textEntrenchment, Wealth, Power, and the Constitution of Democratic Societies, by Paul Starr, New Haven, CT: Yale University Press. 2019. 280 pages, hardcover.Why should we, as Management scholars and educators, care about a book on political diagnosis? The answer is twofold. First, the calibre of the author (Paul Starr), an awardee of both Bancroft and Pulitzer Prizes, a former policy advisor to the Clinton administration, and the author of The Transformation of American Medicine (1982), a book with a profound impact on American policy circles. Second, the core concept (entrenchment) of the book, and its potential to advance the process of institutional development, and the ways in which we can reform and change our institutions to better meet the current and pressing needs of the many, rather than preserve the unequal privileges of a few. In light of the geopolitical, social, and environmental pressures we see currently rising across the world (George, Howard-Grenville, Joshi & Tihanyi, 2016; Howard-Grenville, Buckle, Hoskins & George, 2014) there is no better time to examine whether and how we can address some of these grand challenges by reforming and improving our institutions
M.S. Kutorga and V.M. Vedrov: Conflict of Teacher and Student
No full textВ статье рассматривается конфликт между М.С. Куторгой и его учеником В.М. Ведровым. Исследуются причины конфликта, а также то влияние, которое он оказал на дальнейшую научную карьеру ученика. This article discusses the conflict between M.S. Kutorga and his student V.M. Vedrov. The author investigates the causes of the conflict and its impact on academic career V.M. Vedrov
Ultra-fast escape of a deformable jet-propelled body
No full textIn this work a cephalopod-like deformable body that fills an internal cavity with fluid and expels it to propel an escape manoeuvre, while undergoing a drastic external shape change through shrinking, is shown to employ viscous as well as mainly inviscid hydrodynamic mechanisms to power an impressively fast start. First, we show that recovery of added-mass energy enables a shrinking rocket in a dense inviscid flow to achieve greater escape speed than an identical rocket in a vacuum. Next, we extend the shrinking body results of Weymouth & Triantafyllou (J. Fluid Mech., vol. 702, 2012, pp. 470–487) to three-dimensional bodies and show that three hydrodynamic mechanisms must be combined to achieve rapid escape performance in a viscous fluid: added-mass energy recovery; flow separation elimination; and an optimized energy storage and recovery. In particular, we show that the mechanism of separation elimination achieved through rapid body shrinking, coordinated with the mechanism of recovering the initially imparted added-mass energy, is critical to achieving a high escape speed. Hence a flexible, collapsing body can be vastly superior to a rigid-shell jet-propelled body
AIEDAM thematic collection: a perspective on data-enabled design – design meet data science
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Internet of ThingsDesign, Organisation and Strateg
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