1,080 research outputs found
A measurement of parity-violating gamma-ray asymmetries in polarized cold neutron capture on 35Cl, 113Cd, and 139La
An apparatus for measuring parity-violating asymmetries in gamma-ray emission
following polarized cold neutron capture was constructed as a 1/10th scale test
of the design for the forthcoming n+p->d+gamma experiment at LANSCE. The
elements of the polarized neutron beam, including a polarized 3He neutron spin
filter and a radio frequency neutron spin rotator, are described. Using CsI(Tl)
detectors and photodiode current mode readout, measurements were made of
asymmetries in gamma-ray emission following neutron capture on 35Cl, 113Cd, and
139La targets. Upper limits on the parity-allowed asymmetry were set at the level of 7 x 10^-6 for all three
targets. Parity-violating asymmetries were observed in
35Cl, A_gamma = (-29.1 +- 6.7) x 10^-6, and 139La, A_gamma = (-15.5 +- 7.1) x
10^-6, values consistent with previous measurements.Comment: 19 pages, 4 figures, submitted to Nucl. Instr. and Meth.
Monitoring and evaluation of spatially managed areas: a generic framework and its application
The application of an ecosystem approach to management of the sea requires both integrated and strategic frameworks such as Integrated Coastal Zone Management (ICZM) and the use of marine spatial planning (MSP) to minimize spatial use conflicts and environmental degradation. Such an integrated management promotes sustainable development based on achieving a balance of environmental, social and economic objectives. Here we introduce a first draft of a generic framework which is developed in the EU FP7 project MESMA that gives guidance on how to assess the effectiveness of an existing management within a spatially defined area. More precisely, we define spatially managed areas as geographical entities where a marine planning framework is or will be used to manage multiple human activities in space and time while aiming to maintain ecosystem integrity. The framework consists of seven steps and comprises practical guidance on the selection of operational objectives and related criteria (step 1), the collation and integration of information (steps 2, 3 and 4), performance assessment (step 5), and feedback processes (steps 6 and 7). In the course of the MESMA project, this generic framework will be applied and tested in nine case studies, representing all European seas. Here we highlight the processes and practical tasks involved in each of the framework steps, reflect on the first attempts to implement this framework and identify the requirements for practical tools such as standardized methods to map human activities and assess their cumulative impacts
Vapour-liquid coexistence in many-body dissipative particle dynamics
Many-body dissipative particle dynamics is constructed to exhibit
vapour-liquid coexistence, with a sharp interface, and a vapour phase of
vanishingly small density. In this form, the model is an unusual example of a
soft-sphere liquid with a potential energy built out of local-density dependent
one-particle self energies. The application to fluid mechanics problems
involving free surfaces is illustrated by simulation of a pendant drop.Comment: 8 pages, 6 figures, revtex
Fe@CNT-monoliths for the conversion of carbon dioxide to hydrocarbons:Structural characterisation and Fischer-Tropsch reactivity investigations
High carbon dioxide conversion to hydrocarbons using iron nanoparticle (Fe@CNT) catalysts supported on cordierite monoliths.</p
Precision Measurement of PArity Violation in Polarized Cold Neutron Capture on the Proton: the NPDGamma Experiment
The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is
dedicated to measure with high precision the parity violating asymmetry in the
emission after capture of spin polarized cold neutrons in
para-hydrogen. The measurement will determine unambiguously the weak
pion-nucleon-nucleon () coupling constant {\it f}Comment: Proceedings of the PANIC'05 Conference, Santa Fe, NM, USA, October
24-28, 2005, 3 pages, 2 figure
Investigation of the ferromagnetic transition in the correlated 4d perovskites SrRuRhO
The solid-solution SrRuRhO () is a
variable-electron-configuration system forming in the nearly-cubic-perovskite
basis, ranging from the ferromagnetic 4 to the enhanced paramagnetic
4. Polycrystalline single-phase samples were obtained over the whole
composition range by a high-pressure-heating technique, followed by
measurements of magnetic susceptibility, magnetization, specific heat,
thermopower, and electrical resistivity. The ferromagnetic order in long range
is gradually suppressed by the Rh substitution and vanishes at .
The electronic term of specific-heat shows unusual behavior near the critical
Rh concentration; the feature does not match even qualitatively with what was
reported for the related perovskites (Sr,Ca)RuO. Furthermore, another
anomaly in the specific heat was observed at .Comment: Accepted for publication in PR
Ohm's Law for Plasma in General Relativity and Cowling's Theorem
The general-relativistic Ohm's law for a two-component plasma which includes
the gravitomagnetic force terms even in the case of quasi-neutrality has been
derived. The equations that describe the electromagnetic processes in a plasma
surrounding a neutron star are obtained by using the general relativistic form
of Maxwell equations in a geometry of slow rotating gravitational object. In
addition to the general-relativistic effect first discussed by Khanna \&
Camenzind (1996) we predict a mechanism of the generation of azimuthal current
under the general relativistic effect of dragging of inertial frames on radial
current in a plasma around neutron star. The azimuthal current being
proportional to the angular velocity of the dragging of inertial
frames can give valuable contribution on the evolution of the stellar magnetic
field if exceeds (
is the number density of the charged particles, is the conductivity of
plasma). Thus in general relativity a rotating neutron star, embedded in
plasma, can in principle generate axial-symmetric magnetic fields even in
axisymmetry. However, classical Cowling's antidynamo theorem, according to
which a stationary axial-symmetric magnetic field can not be sustained against
ohmic diffusion, has to be hold in the general-relativistic case for the
typical plasma being responsible for the rotating neutron star.Comment: Accepted for publication in Astrophysics & Space Scienc
A general assessment of environmental and biological features of Windermere and their susceptibility to change
Bassenthwaite (Lake) is one of the larger Cumbrian lakes, certainly one of the most distinctive, and of considerable conservation and amenity value. Although its shores lack sizeable settlements, its main inflow receives sewage effluent from a major tourist centre (Keswick) and is subject to episodic floods. These influences, the growing development of leisure activities at the lake (e.g. sailing, time-share units), and recent road-construction, have led to past appraisals of ecological impacts and lake management. The lake has not been the subject of intense and long-term ecological study, but much scattered information exists that is relevant to future management decisions. In the present Report, commissioned by North West Water, such information - published and unpublished - is surveyed. Especial attention is given to evidence bearing on susceptibility to change, affecting the lake environment and its biota or species of conservation interest. Extensive use has been made of the results of a recent (1986-7) seasonal survey by the FBA
Autoinflammatory periodic fever, immunodeficiency, and thrombocytopenia (PFIT) caused by mutation in actin-regulatory gene WDR1
The importance of actin dynamics in the activation of the inflammasome is becoming increasingly apparent. IL-1β, which is activated by the inflammasome, is known to be central to the pathogenesis of many monogenic autoinflammatory diseases. However, evidence from an autoinflammatory murine model indicates that IL-18, the other cytokine triggered by inflammasome activity, is important in its own right. In this model, autoinflammation was caused by mutation in the actin regulatory gene WDR1 We report a homozygous missense mutation in WDR1 in two siblings causing periodic fevers with immunodeficiency and thrombocytopenia. We found impaired actin dynamics in patient immune cells. Patients had high serum levels of IL-18, without a corresponding increase in IL-18-binding protein or IL-1β, and their cells also secreted more IL-18 but not IL-1β in culture. We found increased caspase-1 cleavage within patient monocytes indicative of increased inflammasome activity. We transfected HEK293T cells with pyrin and wild-type and mutated WDR1 Mutant protein formed aggregates that appeared to accumulate pyrin; this could potentially precipitate inflammasome assembly. We have extended the findings from the mouse model to highlight the importance of WDR1 and actin regulation in the activation of the inflammasome, and in human autoinflammation
Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron
The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2]
for the proton and neutron have been determined from measurements of polarised
cross section asymmetries in deep inelastic scattering of 27.5 GeV
longitudinally polarised positrons from polarised 1H and 3He internal gas
targets. The data were collected in the region above the nucleon resonances in
the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the
proton the contribution to the generalised Gerasimov-Drell-Hearn integral was
found to be substantial and must be included for an accurate determination of
the full integral. Furthermore the data are consistent with a QCD
next-to-leading order fit based on previous deep inelastic scattering data.
Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte
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