1,442 research outputs found

    Angular momentum non-conserving decays in isotropic media

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    Various processes that are forbidden in the vacuum due to angular momentum conservation can occur in a medium that is isotropic and does not carry any angular momentum. We illustrate this by considering explicitly two examples. The first one is the decay of a spin-0 particle into a photon and another spin-0 particle, using a model involving the Yukawa interactions of the scalar particles with a charged fermion field. The second one involves the decay of a neutrino into another neutrino and a graviton, in the standard model of particle interactions augmented with the linearized gravitational couplings.Comment: 22 pages, Latex, uses axodraw.sty. 3 figures embedded in the tex file. This paper contains the same material as that presented in two earlier papers, arXiv:0901.2981 and arXiv:0901.2982, written by us. This version supersedes those two paper

    Studies of Autumn calving suckler cows, bulls at pasture and winter grazing

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    End of project reportMost beef and dairy cows are spring calving leading to distinct seasonality of supply. Calving a proportion of the beef herd in the autumn would lead to a more uniform annual supply of cattle for slaughter and potentially increase the proportion of grazed grass in the diet of the suckler progeny. Autumn calving sucklers also facilitate the use of AI, which should enhance the product quality. This project aimed to address the technical aspects of autumn calving sucklers, which differ from those of spring calvers. The currently available international energy models were evaluated for autumn calving lactating suckler cows using the type of cow typically found in Irish suckler herds (Experiment 1). The winter accommodation of the suckler cow and calf unit and its impact on cow reproductive performance was evaluated (Experiment 2). The final part of the project evolved into component studies to determine the effect of supplementary feed on the performance of grazing bulls (Experiment 3), and the consequences of weanling cattle grazing pasture in winter as an alternative to housing them in winter (Experiments 4 to 7)

    Financial Appraisal of the Banks for Cooperatives

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    This study examines the financial situation of the Farm Credit System Banks for Cooperatives using comparative analysis for the period 1978 through 1991. Profitability and leverage measures of the Banks for Cooperatives are compared with similar measures of large commercial banks. The Banks for Cooperatives were found to have performed as well as large commercial banks. Some differences can be explained as compatible with differences in the goals and objectives of a cooperative versus an investor-owned firm. Most differences can be attributed to the financial strength of the Banks for Cooperatives relative to the commercial banking industry.Agribusiness, Agricultural Finance,

    On the Role of Chaos in the AdS/CFT Connection

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    The question of how infalling matter in a pure state forms a Schwarzschild black hole that appears to be at non-zero temperature is discussed in the context of the AdS/CFT connection. It is argued that the phenomenon of self-thermalization in non-linear (chaotic) systems can be invoked to explain how the boundary theory, initially at zero temperature self thermalizes and acquires a finite temperature. Yang-Mills theory is known to be chaotic (classically) and the imaginary part of the gluon self-energy (damping rate of the gluon plasma) is expected to give the Lyapunov exponent. We explain how the imaginary part would arise in the corresponding supergravity calculation due to absorption at the horizon of the black hole.Comment: 18 pages. Latex file. Minor changes. Final version to appear in Modern Physics Letters

    Nickel in Non-ferrous General Engineering Alloys

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    ALTHOUGH nickel in its wrought forms has important applications as an engineering material, particularly in the chemical and electronic industries, the major usage of the metal, in both ferrous and non-ferrous metallurgy, is as an alloying element. Nickel-base alloys can be broadly divided into the nickel-chromium -base " Superalloys" for high-temperature service , and materials , such as nickel-copper and nickel-chromium- iron alloys, which are used for more general engineering purposes, particularly where resist-ance to corrosion is involved. The technology of the former type of material tends to be rather specialized, since it is concerned very largely with high-temperature properties, and it is not proposed to discuss these high-temperature alloys in this paper but to describe some recent developments in the nickel-base alloys of general engineering interest and in the nickel-containing copper-base and aluminiumbase alloys

    Nickel in Non-ferrous General Engineering Alloys

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    Some recent developments in the nickel-containing copper and aluminium alloys and in nickel alloys of general engineering interest, i.e. excluding the high-temperature alloys, are described in details in the paper. Alloy 625:- The nickel-chromium-molybdenum alloy has recently been developed in the U.S.A. as a high-temperature material. It is now finding application in this field, but other uses which depend on the wet corrosion-resistance are under active investigation

    Gravitational couplings of charged leptons in a medium

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    We calculate the leading order matter-induced corrections to the gravitational interactions of charged leptons and their antiparticles in a medium that contains electrons but not the other charged leptons, such as normal matter. The gravitational coupling, which is universal at the tree level, is found to be flavor-dependent, and also different for the corresponding antiparticles, when the corrections of O(α)O(\alpha) are taken into account. General expressions are obtained for the matter-induced corrections to the gravitational mass in a generic matter background, and explicit formulas for those corrections are given in terms of the macroscopic parameters of the medium for particular conditions of the background gases.Comment: Latex, axodraw, 39 pages. Added a few stylistic corrections and clarifying statements in the treatment of the photon tadpole diagra
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