18,649 research outputs found
Combining Ethological Thinking and Epidemiological Knowledge to Enhance the Naturalness of Organic Livestock Systems
Organic livestock farming places strong emphasis on conditions that allow animals to exhibit behavioural needs. This involves the provision of a natural environment and, in particular, outdoor conditions and a reliance on natural forages. Such environments also allow animals to be effectively integrated into crop production. However, there are potential disease risks associated with these conditions, with control options being partly limited by restrictions on chemoprophylactic measures. Examples from dairy and poultry production demonstrate how a basic understanding of ethology and a knowledge of disease epidemiology can enhance the welfare of animals whilst satisfying the ecological objectives of organic farming. Existing epidemiological models and published data can be used to examine the potential ensuing health hazards and control possibilities and to suggest alternatives
The Life and Works of George Colman the Elder
An attempt has been made in this thesis to present a fully documented Life of Colman, based on examination of all the available material in the form of contemporary accounts, pamphlets and letters. This biography is accompanied by a short account of Colman's literary work other than play-writing, namely his essays in The Connoisseur and later periodicals, and his translations from Terence and Horace$ and by a detailed critical study of his plays, a special effort being made to estimate his indebtedness to earlier English and Continental writers. An attempt is made to ascertain the respective shares of Colman and Garrick in their joint work, The Clandestine Marriage. from the evidence afforded by their letters and by notes found among Colman's papers. A further examination is made of Colman's re-working of earlier plays for representation in his theatres; his versions are compared with the originals and with other adaptations for the eighteenth century stage. Some account, necessarily incomplete, is given of the theatrical history of his plays, and of contemporary and later criticism, drawn from newspapers, magazines and stage histories. His influence as theatrical manager and playwright, particularly the latter, is considered, especially with regard to his opposition to sentimentalism and his support of true comedy, and an attempt is made to indicate his position and the value of his contribution to British drama. An appendix contains a full bibliography of his works, of which no bibliographical account appears hitherto to have been given; a second appendix reproduces the text of the unprinted pantomime, The Genius of Nonsense, from the unique manuscript in the possession of the Henry E. Huntington Librar
Conditional Production of Superpositions of Coherent States with Inefficient Photon Detection
It is shown that a linear superposition of two macroscopically
distinguishable optical coherent states can be generated using a single photon
source and simple all-optical operations. Weak squeezing on a single photon,
beam mixing with an auxiliary coherent state, and photon detecting with
imperfect threshold detectors are enough to generate a coherent state
superposition in a free propagating optical field with a large coherent
amplitude () and high fidelity (). In contrast to all
previous schemes to generate such a state, our scheme does not need photon
number resolving measurements nor Kerr-type nonlinear interactions.
Furthermore, it is robust to detection inefficiency and exhibits some
resilience to photon production inefficiency.Comment: Some important new results added, to appear in Phys.Rev.A (Rapid
Communication
Scattering of dislocated wavefronts by vertical vorticity and the Aharonov-Bohm effect II: Dispersive waves
Previous results on the scattering of surface waves by vertical vorticity on
shallow water are generalized to the case of dispersive water waves. Dispersion
effects are treated perturbatively around the shallow water limit, to first
order in the ratio of depth to wavelength. The dislocation of the incident
wavefront, analogous to the Aharonov-Bohm effect, is still observed. At short
wavelengths the scattering is qualitatively similar to the nondispersive case.
At moderate wavelengths, however, there are two markedly different scattering
regimes according to wether the capillary length is smaller or larger than
times depth. The dislocation is characterized by a parameter that
depends both on phase and group velocity. The validity range of the calculation
is the same as in the shallow water case: wavelengths small compared to vortex
radius, and low Mach number. The implications of these limitations are
carefully considered.Comment: 30 pages, 11 figure
Comparison of LOQC C-sign gates with ancilla inefficiency and an improvement to functionality under these conditions
We compare three proposals for non-deterministic C-sign gates implemented
using linear optics and conditional measurements with non-ideal ancilla mode
production and detection. The simplified KLM gate [Ralph et al, Phys.Rev.A {\bf
65}, 012314 (2001)] appears to be the most resilient under these conditions. We
also find that the operation of this gate can be improved by adjusting the
beamsplitter ratios to compensate to some extent for the effects of the
imperfect ancilla.Comment: to appear in PR
Summary Report of AF1 to Snowmass 2021: Beam Physics and Accelerator Education within the Accelerator Frontier
This report summarizes the findings of the AF1 Topical Subgroup to Snowmass
2021, which investigates beam physics and accelerator education within the
accelerator frontiers (AF). The report focuses primarily on opportunities for
basic accelerator and beam physics, formulated into four grand challenges. In
addition, the report also studies the current status of accelerator education,
outreach and diversity issues. Physics limits of ultimate beams for future
colliders are also briefly discussed.Comment: arXiv admin note: text overlap with arXiv:2203.0681
The LOFT (Large Observatory for X-ray Timing) background simulations
The Large Observatory For X-ray Timing (LOFT) is an innovative medium-class
mission selected for an assessment phase in the framework of the ESA M3 Cosmic
Vision call. LOFT is intended to answer fundamental questions about the
behaviour of matter in the very strong gravitational and magnetic fields around
compact objects. With an effective area of ~10 m^2 LOFT will be able to measure
very fast variability in the X-ray fluxes and spectra. A good knowledge of the
in-orbit background environment is essential to assess the scientific
performance of the mission and to optimize the instrument design. The two main
contributions to the background are cosmic diffuse X-rays and high energy
cosmic rays; also, albedo emission from the Earth is significant. These
contributions to the background for both the Large Area Detector and the Wide
Field Monitor are discussed, on the basis of extensive Geant-4 simulations of a
simplified instrumental mass model.Comment: Proceedings of SPIE, Vol. 8443, Paper No. 8443-209, 201
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