6,275 research outputs found
Envisat - taking the measure of North Atlantic storms
Envisat carries a number of sensors able to provide quantitative information on raining clouds: AATSR delivers information on cloud microphysics (particle size, temperature etc.), MWR-2 gives columnar totals for liquid and vapour forms of water, and RA-2 yields rain rate and wind speed. This paper examines the complementarity of these sensors, with a focussed study on significant rain events in the N. Atlantic, covering both coherent large storms and fronts with smaller scale structure. The difference in liquid water estimates from the infra-red and passive systems appears to be related to the temperature and sizes of drops being detected
Isolated Photons in Deep Inelastic Scattering
Photon radiation at large transverse momenta at colliders is a detailed probe
of hard interaction dynamics. The isolated photon production cross section in
deep inelastic scattering was measured recently by the ZEUS experiment, and
found to be considerably larger than theoretical predictions obtained with
widely used event generators. To investigate this discrepancy, we perform a
dedicated parton-level calculation of this observable, including contributions
from fragmentation and large-angle radiation. Our results are in good agreement
with all aspects of the experimental measurement.Comment: 4 pages, 3 figure
An Evaluation of a Behaviour Assessment to Determine the Suitability of Shelter Dogs for Rehoming
We evaluated a scheme for assessing shelter dog behaviour, which used 28 tests and rated responses from 0 (positive response) to 5 (fear, tonic immobility, or escape attempts). The assessment was evaluated for 236 dogs, and was repeated by a different assessor for 39 dogs approximately 80 days after rehoming to determine relevance of individual test components. A new owner survey evaluated satisfaction with the dog. A total of 130 of 236 dogs passed (score ⤠70), 24 scored 71â80 (referred for behavioural modification), and 82 (score > 80) failed. Scores were mainly unaffected by dog type and environmental variables, but decreased if dog faeces from a previous test was present in the arena during a test. Shelter tests only correlated with repeat tests if there was no direct contact with assessors. Adopters were satisfied with their dogs, despite reporting some behaviour problems. The shelter assessment was therefore robust against most outside influences but did not predict responses to people well
Positive P simulations of spin squeezing in a two-component Bose condensate
The collisional interaction in a Bose condensate represents a non-linearity
which in analogy with non-linear optics gives rise to unique quantum features.
In this paper we apply a Monte Carlo method based on the positive P
pseudo-probability distribution from quantum optics to analyze the efficiency
of spin squeezing by collisions in a two-component condensate. The squeezing
can be controlled by choosing appropiate collision parameters or by
manipulating the motional states of the two components.Comment: 5 pages, 2 figures. Submitted to Phys. Rev.
Coherence Properties of Guided-Atom Interferometers
We present a detailed investigation of the coherence properties of beam
splitters and Mach-Zehnder interferometers for guided atoms. It is demonstrated
that such a setup permits coherent wave packet splitting and leads to the
appearance of interference fringes. We study single-mode and thermal input
states and show that even for thermal input states interference fringes can be
clearly observed, thus demonstrating the multimode operation and the robustness
of the interferometer.Comment: 4 pages, 4 figure
Unitary representations of nilpotent super Lie groups
We show that irreducible unitary representations of nilpotent super Lie
groups can be obtained by induction from a distinguished class of sub super Lie
groups. These sub super Lie groups are natural analogues of polarizing
subgroups that appear in classical Kirillov theory. We obtain a concrete
geometric parametrization of irreducible unitary representations by nonnegative
definite coadjoint orbits. As an application, we prove an analytic
generalization of the Stone-von Neumann theorem for Heisenberg-Clifford super
Lie groups
Influence of oxygen ordering kinetics on Raman and optical response in YBa_2Cu_3O_{6.4}
Kinetics of the optical and Raman response in YBa_2Cu_3O_{6.4} were studied
during room temperature annealing following heat treatment. The superconducting
T_c, dc resistivity, and low-energy optical conductivity recover slowly,
implying a long relaxation time for the carrier density. Short relaxation times
are observed for the B_{1g} Raman scattering -- magnetic, continuum, and phonon
-- and the charge transfer band. Monte Carlo simulations suggest that these two
relaxation rates are related to two length scales corresponding to local oxygen
ordering (fast) and long chain and twin formation (slow).Comment: REVTeX, 3 pages + 4 PostScript (compressed) figure
Molecular polymorphism and epidemiology of Neisseria meningitidis immunoglobulin A1 proteases.
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