31,523 research outputs found

    QCD Chiral restoration at finite TT under the Magnetic field: Studies based on the instanton vacuum model

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    We investigate the chiral restoration at finite temperature (T)(T) under the strong external magnetic field B=B0z^\vec{B}=B_{0}\hat{z} of the SU(2) light-flavor QCD matter. We employ the instanton-liquid QCD vacuum configuration accompanied with the linear Schwinger method for inducing the magnetic field. The Harrington-Shepard caloron solution is used to modify the instanton parameters, i.e. the average instanton size (ρˉ)(\bar{\rho}) and inter-instanton distance (Rˉ)(\bar{R}), as functions of TT. In addition, we include the meson-loop corrections (MLC) as the large-NcN_{c} corrections because they are critical for reproducing the universal chiral restoration pattern. We present the numerical results for the constituent-quark mass as well as chiral condensate which signal the spontaneous breakdown of chiral-symmetry (SBχ\chiS), as functions of TT and BB. Besides we find that the changes for the FπF_\pi and mπm_\pi due to the magnetic field is relatively small, in comparison to those caused by the finite TT effect.Comment: 4 pages, 1 table, 6figs. arXiv admin note: significant text overlap with arXiv:1103.605

    Allocation of Foreign Aid in a Segmented International Context

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    Research on the topic of distribution of foreign aid among recipients is regaining momentum. This is understandable in the light of the knowledge that presently the richest 40 percent of the developing world receives twice as much aid per capita as the poorest 40 percent [UNDP (1994)], while once upon a time foreign aid was sought to accomplish exactly the opposite. The distribution of official development assistance (ODA) is conventionally studied in terms of two models: the ‘recipient needs’ model and the ‘donor interest’ model. In the first, foreign aid flows are seen to satisfy the socio-economic needs of the recipient countries. In the second, national interests of donors, whether these are military, political or commercial, are seen to determine the direction and size of the foreign aid. Empirical studies were made to ascertain and understand whether, on balance, foreign aid is motivated by recipient need or donor interest. There is one class of studies, for example, Mcgillivray (1989), which estimates for donors a compound measure of their allocation bias. The other class of studies, i.e., Maizels and Nissanke (1984) and Grilli and Riess (1992), employs regression analysis to explain allocation of foreign aid by representative variables of recipient need and donor interest. Because the primary pursuit of these studies was to give an overall judgement on foreign aid motivations, insufficient attention was given to differentiations among donors, between recipients, and over time. The allocation policies of donors can be observed to differ between large donors and small donors, whereby the two types of donors are often tied to different groups of recipient countries. Moreover, other arguments than recipient need and donor interest, such as historic and geographical ties and the changing world political order, play important roles.

    EFFECTIVE TECHNIQUES IN ESP TEACHING AND LEARNING

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    ASSESSMENT STRATEGIES IN ESP COURSE AS A WAY FOR MOTIVATING STUDENT LEARNING

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    The role of assessment in enhancing student motivation to learn English for specific purposes is analysed. The research results about student attitudes towards assessment strategies are presented. The assessment types are described. The importance of self-assessment and student involvement into the process of assessment is emphasized

    A simple guide to water quality management in fish ponds

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    (37 page document

    Noun Strings: Lexical Problems in the ESP Discourse

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    The application of pesticides to grape bunches

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    The application of pesticides to grape bunches is complicated by the different shapes and forms of the grape bunch during growth. Initially the grape bunch has a very porous structure, while in later stages the grapes are closely packed. We consider estimates of the flow velocity through the grape bunch, droplet density within the spray, probability of droplet impaction on a bunch or individual grape and the maximum size of drop that can adhere to a grape surface

    On Hoyle-Narlikar-Wheeler mechanism of vibration energy powered magneto-dipole emission of neutron stars

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    We revisit the well-known Hoyle-Narlikar-Wheeler proposition that neutron star emerging in the magnetic-flux-conserving process of core-collapse supernova can convert the stored energy of Alfven vibrations into power of magneto-dipole radiation. We show that the necessary requirement for the energy conversion is the decay of internal magnetic field. In this case the loss of vibration energy of the star causes its vibration period, equal to period of pulsating emission, to lengthen at a rate proportional to the rate of magnetic field decay. These prediction of the model of vibration powered neutron star are discussed in juxtaposition with data on pulsating emission of magnetars whose radiative activity is generally associated with the decay of ultra strong magnetic field.Comment: Accepted for publication in Astrophysics & Space Scienc

    Dietary carbohydrate requirement of Heterobranchus longifilis

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    The dietary carbohydrate requirement of Heterobranchus longifilis was evaluated in two separate experiments.In the first experiment, varying levels of carbohydrate ranging from 28, 24 to58 72% were fed to the fish of mean weight 1.83~c0.02g. Results revealed that the polynomial regression curve for the mean weight gain and the carbohydrate levels did not present a point where Y-max is equal to X-max and so the requirement was not obtained. The second experiment was therefore, conducted with lower levels of carbohydrate ranging from 17.00 to 20.86% and fed to fish with mean weight 0.49~c0.02g. Based on growth and feed efficiency data the carbohydrate requirement was determined to be 19.5
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