481 research outputs found

    Comparative Study on the Natural and Synthetic Hormones ofClarias gariepinus Broodstock

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    The study was carried out for six (6) weeks at the Department of Fisheries Teaching and Research farm, Modibbo Adama University, Yola, to compare the reproductive performance of Clarias gariepinus using synthetic (ovaprim) and natural (C. gariepinus pituitary extract) hormones . At the end of the feeding trial, the fecundity, percentage fertilization, hatchability, and survival rates of the hatchlings were estimated using standard procedure. The hatchlings were further raised for six weeks and the increase in weight was determined. The results showed that female broodstock injected with C. gariepinus pituitary extract (CgPE) had a higher fecundity (124,000) while the female injected with Ovaprim had 65,000 eggs. The weight of the testes significantly differed (p<0.05) across the treatments, the right lobe weighed 1.63g while the left lobe weighed 1.98g . Subsequently, a higher fertilization rate was recorded in CgPE (91.1%) while Ovaprim had 85.55% . However, Ovaprim had a higher percentage hatchability of 82.93% while CgPE had 82.73% . At the end of the six (6) weeks feeding period, the survival rate was higher in the fish treated with CgPE (82.31%) while the fish injected with Ovaprim had 79.68% . The research exposed the efficacy of using CgPE in the absence of synthetic hormone, CgPE is a preferred substitute that Hatchery managers can utilize for fingerlings production

    Spiritual care for cancer patients in Iran

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    Background: Studies have shown that a return to spirituality is a major coping response in cancer patients so that therapists can adopt a holistic approach by addressing spirituality in their patient care. The present study was conducted to develop a guideline in the spiritual field for healthcare providers who serve cancer patients in Iran. Materials and Methods: Relevant statements were extracted from scientific documents that through study questions were reviewed and modified by a consensus panel. Results: The statements were arranged in six areas, including spiritual needs assessment, spiritual care candidates, the main components of spiritual care, spiritual care providers, the settings of spiritual care and the resources and facilities for spiritual care. Conclusions: In addition to the development and preparation of these guidelines, health policy-makers should also seek to motivate and train health service providers to offer these services and facilitate their provision and help with widespread implementation

    QCD Corrections and the Endpoint of the Lepton Spectrum in Semileptonic B Decays

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    Recently, Neubert has suggested that a certain class of nonperturbative corrections dominates the shape of the electron spectrum in the endpoint region of semileptonic BB decay. Perturbative QCD corrections are important in the endpoint region. We study the effects of these corrections on Neubert's proposal. The connection between the endpoint of the electron spectrum in semileptonic BB decay and the photon spectrum in bsγb\rightarrow s\gamma is outlined.Comment: 18 pages, uses REVTeX, UCSD/PTH 93-38, CALT-68-1910, JHU-TIPAC-930029 (some changes to the discussion of subleading radiative corrections, and minor typos fixed

    Branching ratio and CP asymmetry of Bsπ+πB_s \to \pi^+ \pi^- decays in the perturbative QCD approach

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    In this paper, we calculate the decay rate and CP asymmetry of the Bsπ+πB_s \to \pi^+\pi^- decay in perturbative QCD approach with Sudakov resummation. Since none of the quarks in final states is the same as those of the initial BsB_s meson, this decay can occur only via annihilation diagrams in the standard model. Besides the current-current operators, the contributions from the QCD and electroweak penguin operators are also taken into account. We find that (a) the branching ratio is about 4×1074 \times 10^{-7}; (b) the penguin diagrams dominate the total contribution; and (c) the direct CP asymmetry is small in size: no more than 33% ; but the mixing-induced CP asymmetry can be as large as ten percent testable in the near future LHC-b experiments.Comment: 12 pages, 4 figures included, RevTe

    Measurement of hybrid content of heavy quarkonia using lattice NRQCD

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    Using lowest-order lattice NRQCD to create heavy meson propagators and applying the spin-dependent interaction, cBg2mqσBc_B^{} \frac{-g}{2m_q}\vec\sigma\cdot\vec{B}, at varying intermediate time slices, we compute the off-diagonal matrix element of the Hamiltonian for the quarkonium-hybrid two-state system. Thus far, we have results for one set of quenched lattices with an interpolation in quark mass to match the bottomonium spectrum. After diagonalization of the two-state Hamiltonian, we find the ground state of the Υ\Upsilon to show a 0.0035(1)cB20.0035(1)c_B^2 (with cB21.53.1c_B^2 \sim 1.5-3.1) probability admixture of hybrid, bbˉg>|b\bar{b}g>.Comment: 11 pages, 4 figures, to appear in Phys Rev

    Two-loop matching of the dipole operators for bsγb \to s \gamma and bsgluonb \to s gluon

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    The order αs\alpha_s corrections to the Wilson coefficients of the dipole operators (O7,O8O_7,O_8) at the matching scale μ=mW\mu =m_W are a crucial ingredient for a complete next- to-leading logarithmic calculation of the branching ratio for bsγb \to s \gamma. Given the phenomenological relevance and the fact that this two-loop calculation has been done so far only by one group [1], we present a detailed re-calculation using a different method. Our results are in complete agreement with those in ref. [1].Comment: 24 pages, latex, 6 figures include

    Recalculation of QCD Corrections to bsγb \to s \gamma Decay

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    We give a more complete calculation of bsγb \to s\gamma decay, including leading log QCD corrections from mtopm_{top} to MWM_W in addition to corrections from MWM_{W} to mbm_b. We have included the full set of dimension-6 operators and corrected numerical mistakes of anomalous dimensions in a previous paper\cite{Cho}. Comparing with the calculations without QCD running from mtopm_{top} to MWM_W\cite{Mis}, the inclusive decay rate is found to be enhanced. At mt=150m_t=150GeV, it results in 12\% enhancement, and for mt=250m_t=250GeV, 15\% is found. The total QCD effect makes an enhanced factor of 4.2 at mt=150m_t=150GeV, and 3.2 for mt=250m_t=250GeV.Comment: 16 pages, 7 figures (uuencoded ps files), Changes of description. To appear in Phys. Rev.

    Scaling of the B and D meson spectrum in lattice QCD

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    We give results for the BB and the DD meson spectrum using NRQCD on the lattice in the quenched approximation. The masses of radially and orbitally excited states are calculated as well as SS-wave hyperfine and PP-wave fine structure. Radially excited PP-states are observed for the first time. Radial and orbital excitation energies match well to experiment, as does the strange-non-strange SS-wave splitting. We compare the light and heavy quark mass dependence of various splittings to experiment. Our BB-results cover a range in lattice spacings of more than a factor of two. Our DD-results are from a single lattice spacing and we compare them to numbers in the literature from finer lattices using other methods. We see no significant dependence of physical results on the lattice spacing. PACS: 11.15.Ha 12.38.Gc 14.40.Lb 14.40.NdComment: 78 pages, 29 tables, 30 figures Revised version. Minor corrections to spelling and wordin

    Charmonium Spectrum from Quenched Anisotropic Lattice QCD

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    We present a detailed study of the charmonium spectrum using anisotropic lattice QCD. We first derive a tree-level improved clover quark action on the anisotropic lattice for arbitrary quark mass. The heavy quark mass dependences of the improvement coefficients, i.e. the ratio of the hopping parameters ζ=Kt/Ks\zeta=K_t/K_s and the clover coefficients cs,tc_{s,t}, are examined at the tree level. We then compute the charmonium spectrum in the quenched approximation employing ξ=as/at=3\xi = a_s/a_t = 3 anisotropic lattices. Simulations are made with the standard anisotropic gauge action and the anisotropic clover quark action at four lattice spacings in the range asa_s=0.07-0.2 fm. The clover coefficients cs,tc_{s,t} are estimated from tree-level tadpole improvement. On the other hand, for the ratio of the hopping parameters ζ\zeta, we adopt both the tree-level tadpole-improved value and a non-perturbative one. We calculate the spectrum of S- and P-states and their excitations. The results largely depend on the scale input even in the continuum limit, showing a quenching effect. When the lattice spacing is determined from the 1P1S1P-1S splitting, the deviation from the experimental value is estimated to be \sim30% for the S-state hyperfine splitting and \sim20% for the P-state fine structure. Our results are consistent with previous results at ξ=2\xi = 2 obtained by Chen when the lattice spacing is determined from the Sommer scale r0r_0. We also address the problem with the hyperfine splitting that different choices of the clover coefficients lead to disagreeing results in the continuum limit.Comment: 43 pages, 49 eps figures, revtex; minor changes, version to appear in Physical Review

    Strong Phases and Factorization for Color Suppressed Decays

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    We prove a factorization theorem in QCD for the color suppressed decays B0-> D0 M0 and B0-> D*0 M0 where M is a light meson. Both the color-suppressed and W-exchange/annihilation amplitudes contribute at lowest order in LambdaQCD/Q where Q={mb, mc, Epi}, so no power suppression of annihilation contributions is found. A new mechanism is given for generating non-perturbative strong phases in the factorization framework. Model independent predictions that follow from our results include the equality of the B0 -> D0 M0 and B0 -> D*0 M0 rates, and equality of non-perturbative strong phases between isospin amplitudes, delta(DM) = delta(D*M). Relations between amplitudes and phases for M=pi,rho are also derived. These results do not follow from large Nc factorization with heavy quark symmetry.Comment: 38 pages, 6 figs, typos correcte
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