1,699 research outputs found
Of executive preferences and societal constraints: the domestic politics of the transatlantic GMO dispute
When the transatlantic trade dispute over genetically modified organisms came to a boil in the late 1990s and early 2000s it was widely expected to be highly conflictual. The United States was, almost universally, expected to challenge fundamentally the European Union’s regulatory system for GMOs before the World Trade Organisation and was equally universally expected to win the case. The EU was widely, albeit not universally, expected to refuse to comply with the ruling. In keeping with most of the international political economy literature on trade disputes, both of these expectations were rooted in assessments of societal demands for action and resistance. Both expectations, however, were confounded; the US (and its co-complainants) filed a narrow challenge focusing on the EU’s failure to apply its own procedures; and the EU, somewhat falteringly, has resumed approvals of GMOs. Applying a two-level-game framework, this article argues that this relatively cooperative outcome is explained by the executives of both polities exercising their autonomy to pursue policies closer to the preferences of the other polity than their median domestic constituents would have preferred. This article, therefore, makes the case for taking government preferences and autonomy seriously when analysing the outcomes of trade disputes. Moreover, it emphasises that compliance with international rules engages with on-going internal policy processes and debate
Theory and simulations of a gyrotron backward wave oscillator using a helical interaction waveguide
A gyrotron backward wave oscillator (gyro-BWO) with a helically corrugated interaction waveguide demonstrated its potential as a powerful microwave source with high efficiency and a wide frequency tuning range. This letter presents the theory describing the dispersion properties of such a waveguide and the linear beam-wave interaction. Numerical simulation results using the PIC code MAGIC were found to be in excellent agreement with the output measured from a gyro-BWO experiment
Production of UCN by Downscattering in superfluid He4
Ultra-cold neutrons (UCN) are neutrons with energies so low they can be
stored in material bottles and magnetic traps. They have been used to provide
the currently most accurate experiments on the neutron life time and electric
dipole moment. UCN can be produced in superfluid Helium at significantly higher
densities than by other methods. The predominant production process is usually
by one phonon emission which can only occur at a single incident neutron energy
because of momentum and energy conservation. However UCN can also be produced
by multiphonon processes. It is the purpose of this work to examine this
multiphonon production of UCN. We look at several different incident neutron
spectra, including cases where the multiphonon production is significant, and
see how the relative importance of multiphonon production is influenced by the
incident spectrum.Comment: 3 figures, improved presentation after comments from xxx reader
Pulse shape analysis in segmented detectors as a technique for background reduction in Ge double-beta decay experiments
The need to understand and reject backgrounds in Ge-diode detector
double-beta decay experiments has given rise to the development of pulse shape
analysis in such detectors to discern single-site energy deposits from
multiple-site deposits. Here, we extend this analysis to segmented Ge detectors
to study the effectiveness of combining segmentation with pulse shape analysis
to identify the multiplicity of the energy deposits.Comment: 12 pages, 13 figures, will be submitted to NI
An Apparatus to Control and Monitor the Para-D2 Concentration in a Solid Deuterium, Superthermal Source of Ultra-cold Neutrons
Controlling and measuring the concentration of para-D2 is an essential step
toward realizing solid deuterium as an intense ultra-cold neutron (UCN) source.
To this end, we implemented an experimental technique to convert para- to
ortho-deuterium molecules by flowing D2 gas through a cryogenic cell filled
with paramagnetic hydrous ferric oxide granules. This process efficiently
reduced the para-D2 concentration from 33.3% to 1.5%. Rotational Raman
spectroscopy was applied to measure the residual para-D2 contamination to
better than 2 parts in 10^3, and the hydrogen contamination to 1 part in 10^3.
We also contrast our optical technique to conventional thermal conductivity
measurements of the para-D2 concentration, reporting some of the relevant
strengths and weaknesses of our implementation of each technique.Comment: accepted for publication in NIM
EIS/Hinode observations of Doppler flow seen through the 40 arcsec wide slit
The Extreme ultraviolet Imaging Spectrometer (EIS) on board Hinode is the
first solar telescope to obtain wide slit spectral images that can be used for
detecting Doppler flows in transition region and coronal lines on the Sun and
to relate them to their surrounding small scale dynamics. We select EIS lines
covering the temperature range 6x10^4 K to 2x10^6 K that give spectrally pure
images of the Sun with the 40 arcsec slit. In these images Doppler shifts are
seen as horizontal brightenings. Inside the image it is difficult to
distinguish shifts from horizontal structures but emission beyond the image
edge can be unambiguously identified as a line shift in several lines separated
from others on their blue or red side by more than the width of the
spectrometer slit (40 pixels). In the blue wing of He II, we find a large
number of events with properties (size and lifetime) similar to the
well-studied explosive events seen in the ultraviolet spectral range.
Comparison with X-Ray Telescope (XRT) images shows many Doppler shift events at
the footpoints of small X-ray loops. The most spectacular event observed showed
a strong blue shift in transition region and lower corona lines from a small
X-ray spot that lasted less than 7 min. The emission appears to be near a cool
coronal loop connecting an X-ray bright point to an adjacent region of quiet
Sun. The width of the emission implies a line-of-sight velocity of 220 km/s. In
addition, we show an example of an Fe XV shift with a velocity about 120 km/s,
coming from what looks like a narrow loop leg connecting a small X-ray
brightening to a larger region of X-ray emission.Comment: 12 pages, 8 figures, to be published in Solar Physic
Production of Radioactive Nuclides in Inverse Reaction Kinematics
Efficient production of short-lived radioactive isotopes in inverse reaction
kinematics is an important technique for various applications. It is
particularly interesting when the isotope of interest is only a few nucleons
away from a stable isotope. In this article production via charge exchange and
stripping reactions in combination with a magnetic separator is explored. The
relation between the separator transmission efficiency, the production yield,
and the choice of beam energy is discussed. The results of some exploratory
experiments will be presented.Comment: 10 pages, 4 figures, to be submitted to Nucl. Instr. and Met
Glucose Promotes Stress Resistance in the Fungal Pathogen \u3ci\u3eCandida albicans\u3c/i\u3e
Metabolic adaptation, and in particular the modulation of carbon assimilatory pathways during disease progression, is thought to contribute to the pathogenicity of Candida albicans. Therefore, we have examined the global impact of glucose upon the C. albicans transcriptome, testing the sensitivity of this pathogen to wide-ranging glucose levels (0.01, 0.1, and 1.0%). We show that, like Saccharomyces cerevisiae, C. albicans is exquisitely sensitive to glucose, regulating central metabolic genes even in response to 0.01% glucose. This indicates that glucose concentrations in the bloodstream (approximate range 0.05–0.1%) have a significant impact upon C. albicans gene regulation. However, in contrast to S. cerevisiae where glucose down-regulates stress responses, some stress genes were induced by glucose in C. albicans. This was reflected in elevated resistance to oxidative and cationic stresses and resistance to an azole antifungal agent. Cap1 and Hog1 probably mediate glucose-enhanced resistance to oxidative stress, but neither is essential for this effect. However, Hog1 is phosphorylated in response to glucose and is essential for glucose-enhanced resistance to cationic stress. The data suggest that, upon entering the bloodstream, C. albicans cells respond to glucose increasing their resistance to the oxidative and cationic stresses central to the armory of immunoprotective phagocytic cells
Glucose Promotes Stress Resistance in the Fungal Pathogen \u3ci\u3eCandida albicans\u3c/i\u3e
Metabolic adaptation, and in particular the modulation of carbon assimilatory pathways during disease progression, is thought to contribute to the pathogenicity of Candida albicans. Therefore, we have examined the global impact of glucose upon the C. albicans transcriptome, testing the sensitivity of this pathogen to wide-ranging glucose levels (0.01, 0.1, and 1.0%). We show that, like Saccharomyces cerevisiae, C. albicans is exquisitely sensitive to glucose, regulating central metabolic genes even in response to 0.01% glucose. This indicates that glucose concentrations in the bloodstream (approximate range 0.05–0.1%) have a significant impact upon C. albicans gene regulation. However, in contrast to S. cerevisiae where glucose down-regulates stress responses, some stress genes were induced by glucose in C. albicans. This was reflected in elevated resistance to oxidative and cationic stresses and resistance to an azole antifungal agent. Cap1 and Hog1 probably mediate glucose-enhanced resistance to oxidative stress, but neither is essential for this effect. However, Hog1 is phosphorylated in response to glucose and is essential for glucose-enhanced resistance to cationic stress. The data suggest that, upon entering the bloodstream, C. albicans cells respond to glucose increasing their resistance to the oxidative and cationic stresses central to the armory of immunoprotective phagocytic cells
Nab: Measurement Principles, Apparatus and Uncertainties
The Nab collaboration will perform a precise measurement of 'a', the
electron-neutrino correlation parameter, and 'b', the Fierz interference term
in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS,
using a novel electric/magnetic field spectrometer and detector design. The
experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will
provide an independent measurement of lambda = G_A/G_V, the ratio of
axial-vector to vector coupling constants of the nucleon. Nab also plans to
perform the first ever measurement of 'b' in neutron decay, which will provide
an independent limit on the tensor weak coupling.Comment: 12 pages, 6 figures, 1 table, talk presented at the International
Workshop on Particle Physics with Slow Neutrons, Grenoble, 29-31 May 2008; to
appear in Nucl. Instrum. Meth. in Physics Research
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