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Bluetongue (BT) is a disease of ruminants caused by the bluetongue virus (BTV) transmitted by bites of Culicoides midges. Bluetongue has a worldwide prevalence and mortality in sheep varies from 0 to 30%. There are at least 27 BTV serotypes showing no or little cross protection. In 2006, BTV has been reported in north-western Europe for the first time, and has caused a huge outbreak with large economic losses. BTV (family Reoviridae, genus Orbivirus) is a non-enveloped virus with a ten-segmented dsRNA genome encoding seven viral proteins (VP1-7) and four non-structural (NS1-4) proteins. VP2 is the outer capsid protein, and is the serotype specific target for neutralizing antibodies. NS3 and its N-terminal truncated form NS3a (Seg-10) enable virus release from infected cells. Currently, live-attenuated and inactivated BT vaccines have been marketed, but these have several shortcomings. Therefore there is a need for next-generation types of BT vaccines with improved vaccine profile. Here, such a novel vaccine platform based on BTV without NS3/NS3a expression is described. BTV based on lab adapted strain BTV1, vaccine related BTV6, and virulent BTV8 were equipped with a deletion in Seg-10 abolishing NS3/NS3a expression and with Seg-2 encoding serotype determining VP2 from serotype 8. All three vaccine candidates were not virulent in sheep and did not show viremia, whereas seroconversion was dependent on replication of vaccine virus. This suggests that BTV without NS3/NS3a replicates only locally. Sheep were completely protected against infection of virulent BTV8. In a second efficacy experiment in sheep, complete serotype specific protection was demonstrated at nine weeks after booster vaccination. A competitive ELISA based on NS3 antibodies enables the differentiation of infected from vaccinated animals (DIVA). Uptake of the NS3/NS3a knockout vaccine candidate by midges is highly unlikely, due to the absence of viremia after vaccination. This vaccine candidate has therefore been named the Disabled Infectious, Single Animal (DISA) vaccine. Additionally, replication of BT DISA vaccine in midges is abolished as shown after injection of Culicoides sonorensis midges. The BT DISA vaccine platform was also adapted for other BTV serotypes by exchange of Seg-2 (VP2) or by use of chimeric Seg-2 originating from two different serotypes. The latter showed a broader application of the vaccine platform and neutralizing responses against both ancestor serotypes. In conclusion, BT DISA vaccine is effective, safe, enables DIVA, and can be used for many serotypes by exchange of VP2

On narrowing coated conductor film: emergence of granularity-induced field hysteresis of transport critical current

Critical current density Jc in polycrystalline or granular superconducting material is known to be hysteretic with applied field H due to the focusing of field within the boundary between adjacent grains. This is of concern in the so-called coated conductors wherein superconducting film is grown on a granular, but textured surface of a metal substrate. While previous work has mainly been on Jc determined using induced or magnetization currents, the present work utilizes transport current via an applied potential in strip geometry. It is observed that the effect is not as pronounced using transport current, probably due to a large difference in criterion voltage between the two types of measurements. However, when the films are narrowed by patterning into 200-, 100-, or 80-micron, the hysteresis is clearly seen, because of the forcing of percolation across higher-angle grain boundaries. This effect is compared for films grown on ion-beam-assisted-deposited (IBAD) YSZ substrate and those grown on rolling-assisted-biaxially-textures substrates (RABiTS) which have grains that are about ten times larger. The hysteresis is more pronounced for the latter, which is more likely to have a weak grain boundary spanning the width of the microbridge. This is also of concern to applications in which coated conductors will be striated in order to reduce of AC losses.Comment: text-only: 10 pages, plus 5 figures on 5 page

Statistical mechanics of the international trade network

Analyzing real data on international trade covering the time interval 1950-2000, we show that in each year over the analyzed period the network is a typical representative of the ensemble of maximally random weighted networks, whose directed connections (bilateral trade volumes) are only characterized by the product of the trading countries' GDPs. It means that time evolution of this network may be considered as a continuous sequence of equilibrium states, i.e. quasi-static process. This, in turn, allows one to apply the linear response theory to make (and also verify) simple predictions about the network. In particular, we show that bilateral trade fulfills fluctuation-response theorem, which states that the average relative change in import (export) between two countries is a sum of relative changes in their GDPs. Yearly changes in trade volumes prove that the theorem is valid.Comment: 6 pages, 2 figure

Microwave Near-Field Imaging of Electric Fields in a Superconducting Microstrip Resonator

We describe the use of a cryogenic near-field scanning microwave microscope to image microwave electric fields from superconducting and normal-metal microstrip resonators. The microscope employs an open-ended coaxial probe and operates from 77 to 300 K in the 0.01-20 GHz frequency range with a spatial resolution of about 200 mm. We describe the operation of the system and present microwave images of Cu and Tl2Ba2CaCu2O8 microstrip resonators, showing standing wave patterns at the fundamental and second harmonic frequencies.Comment: 9 pages, 3 eps figure

Near-Field Scanning Microwave Microscopy: Measuring Local Microwave Properties and Electric Field Distributions

We describe the near-field microwave microscopy of microwave devices on a length scale much smaller than the wavelength used for imaging. Our microscope can be operated in two possible configurations, allowing a quantitative study of either material properties or local electric fields.Comment: 4 pages, 8 figures, minor corrections to text and 2 figure

Near-Field Microwave Microscopy of Materials Properties

Near-field microwave microscopy has created the opportunity for a new class of electrodynamics experiments of materials. Freed from the constraints of traditional microwave optics, experiments can be carried out at high spatial resolution over a broad frequency range. In addition, the measurements can be done quantitatively so that images of microwave materials properties can be created. We review the five major types of near-field microwave microscopes and discuss our own form of microscopy in detail. Quantitative images of microwave sheet resistance, dielectric constant, and dielectric tunability are presented and discussed. Future prospects for near-field measurements of microwave electrodynamic properties are also presented.Comment: 31 pages, 9 figures, lecture given at the 1999 NATO ASI on Microwave Superconductivity Changes suggested by editor, including full reference

Frequency Following Imaging of Electric Fields from Resonant Superconducting Devices using a Scanning Near-Field Microwave Microscope

We have developed a scanning near-field microwave microscope that operates at cryogenic temperatures. Our system uses an open-ended coaxial probe with a 200 mm inner conductor diameter and operates from 77 to 300 K in the 0.01-20 GHz frequency range. In this paper, we present microwave images of the electric field distribution above a Tl2Ba2CaCu2O8 microstrip resonator at 77 K, measured at several heights. In addition, we describe the use of a frequency-following circuit to study the influence of the probe on the resonant frequency of the device.Comment: 4 pages, postscript file with 6 figures conference proceeding for the Applied Superconductivity Conference 199

Superconducting Material Diagnostics using a Scanning Near-Field Microwave Microscope

We have developed scanning near-field microwave microscopes which can image electrodynamic properties of superconducting materials on length scales down to about 2 $\mu$m. The microscopes are capable of quantitative imaging of sheet resistance of thin films, and surface topography. We demonstrate the utility of the microscopes through images of the sheet resistance of a YBa2Cu3O7-d thin film wafer, images of bulk Nb surfaces, and spatially resolved measurements of Tc of a YBa2Cu3O7-d thin film. We also discuss some of the limitations of the microscope and conclude with a summary of its present capabilities.Comment: 6 pages with 9 figures, Proceedings of the Applied Superconductivity Conference 199