453 research outputs found

    The Effectiviness of Ketapang (Terminalia Cattapa L.) Leave Extract for the Treatment of Aeromonas Salmonicida Infection in Catfish (Pangasioniodon Hypophthalmus)

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    Catfish is one of the fish species with certain advantages that attract the farmers interest to culture. The species becomes popular following the successful spawning in the pond. Additionally, catfishes have high economic value due to their rapid growth and response to good artificial feed. Their farming activities are inseparable from concerns about their potential diseases. Diseases in farmed fish can be caused by fungi, parasites, bacteria and viruses. One type of bacterium to take serious control is Aeromonas salmonicida. This pathogenic bacteria may cause furuncle and death of farmed fish. The use of ketapang leaves is effective in inhibiting or killing the pathogenic A. salmonicida in catfish. In the present study, each test used a sample of 10 catfishes of approximately 10 cm in size. Parameters of the test consist of survival rates and pathologic lesions. The feed treatment consisted of ketapang leaf extract in concentrations of 100, 200, and 300 mg / ml, and a positive control and a negative control. Each treatment consisted of 3 replicates, and were analyzed statistically. The results indicated that the LD50 (Lethal Dose), MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) are 107 cfu/ml, 50 mg/ml and 100 mg/ml, respectively. The most effective concentration of ketapang leaf for the treatment of A. salmonicida infection in the catfish is 200 mg/ml. This is indicated by the highest level of catfish survival and the lowest rate of the pathologic lesions

    Top quark precision physics at the International Linear Collider

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    Top quark production in the process e+ettˉe^+e^- \rightarrow t\bar{t} at a future linear electron positron collider with polarized beams is a powerful tool to determine the scale of new physics. Studies at the \ttbar threshold will allow for precise determination of the top quark mass in a well defined theoretical framework. At higher energies vector, axial vector and tensorial CP conserving couplings can be separately determined for the photon and the Z0Z^0 component in the electro-weak production process. The sensitivity to new physics would be dramatically improved w.r.t. to what expected from LHC for electroweak couplings.Comment: White paper for Snowmass CSS 201

    Final-State Interactions in e^+e^- -> t\bar{t} -> b l^+ \nu \bar{b} W^- Near Top Quark Threshold

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    We calculate final-state interaction corrections to the energy-angular distribution of l^+ in semi-leptonic top quark decay, where the parent top quark is produced via e^+e^- -> t\bar{t} near threshold. These are the corrections due to gluon exchange between t and \bar{b} (\bar{t} and b) and between b and \bar{b}. Combining with previously known other corrections, we explicitly write down the l^+ energy-angular distribution including the full O(alpha_s)=O(beta) corrections near t\bar{t} threshold. Numerical analyses of the final-state interaction corrections are given. We find that they deform the l^+ distribution typically at the 10% level. We also find that all qualitative features of the numerical results can be understood from intuitive pictures. The mechanisms of various effects of the final-state interactions are elucidated. Finally we define an observable which is proper to the decay process of the top quark (dependent only on d\Gamma_{t -> b l^+ \nu}/ dE_l d\Omega_l of a free polarized top quark) near t\bar{t} threshold. Such a quantity will be useful in extracting the decay property of the top quark using the highly polarized top quark samples.Comment: Section 6 is enlarged substantially and a paragraph is added to Section 8 correspondingly. Reference list is also improved. (27 pages including figures, LaTeX

    Quarkonium Spectroscopy and Perturbative QCD: A New Perspective

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    We study the energy spectrum of bottomonium in perturbative QCD, taking alpha_s(Mz)=0.1181 +/- 0.0020 as input and fixing m_b^{MSbar}(m_b^{MSbar}) on the Upsilon(1S) mass. Contrary to wide beliefs, perturbative QCD reproduces reasonably well the gross structure of the spectrum as long as the coupling constant remains smaller than one. We perform a detailed analysis and discuss the size of non-perturbative effects. A new qualitative picture on the structure of the bottomonium spectrum is provided. The lowest-lying (c,cbar) and (b,cbar) states are also examined.Comment: 12 pages, 2 figures; Discussion on ultra-soft effects included; Some conservative error estimates added; Version to appear in Phys.Lett.

    Chemo-Sensitive Running Droplet

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    Chemical control of the spontaneous motion of a reactive oil droplet moving on a glass substrate under an aqueous phase is reported. Experimental results show that the self-motion of an oil droplet is confined on an acid-treated glass surface. The transient behavior of oil-droplet motion is also observed with a high-speed video camera. A mathematical model that incorporates the effect of the glass surface charge is built based on the experimental observation of oil-droplet motion. A numerical simulation of this mathematical model reproduced the essential features concerning confinement within a certain chemical territory of oil-droplet motion, and also its transient behavior. Our results may shed light on physical aspects of reactive spreading and a chemotaxis in living things.Comment: 17 pages, 10 figure

    Momentum Distributions in ttˉt\bar t

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    We apply the Green function formalism for ttˉt-\bar t production and decay near threshold in a study of the effects due to the momentum dependent width for such a system. We point out that these effects are likely to be much smaller than expected from the reduction of the available phase space. The Lippmann--Schwinger equation for the QCD chromostatic potential is solved numerically for SS partial wave. We compare the results on the total cross section, top quark intrinsic momentum distributions and on the energy spectra of WW bosons from top quark decays with those obtained for the constant width.Comment: 12 pages (without figures) (11 (sub)figures available on request), Karlsruhe preprint TTP93-11, hep-ph/yymmnn

    Improved Perturbative QCD Approach to the Bottomonium Spectrum

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    Recently it has been shown that the gross structure of the bottomonium spectrum is reproduced reasonably well within the non-relativistic boundstate theory based on perturbative QCD. In that calculation, however, the fine splittings and the S-P level splittings are predicted to be considerably narrower than the corresponding experimental values. We investigate the bottomonium spectrum within a specific framework based on perturbative QCD, which incorporates all the corrections up to O(alpha_S^5 m_b) and O(alpha_S^4 m_b), respectively, in the computations of the fine splittings and the S-P splittings. We find that the agreement with the experimental data for the fine splittings improves drastically due to an enhancement of the wave functions close to the origin as compared to the Coulomb wave functions. The agreement of the S-P splittings with the experimental data also becomes better. We find that natural scales of the fine splittings and the S-P splittings are larger than those of the boundstates themselves. On the other hand, the predictions of the level spacings between consecutive principal quantum numbers depend rather strongly on the scale mu of the operator \propto C_A/(m_b r^2). The agreement of the whole spectrum with the experimental data is much better than the previous predictions when mu \simeq 3-4 GeV for alpha_S(M_Z)=0.1181. There seems to be a phenomenological preference for some suppression mechanism for the above operator.Comment: 26 pages, 16 figures. Minor changes, to be published in PR

    Precision W-boson and top-quark mass determinations at a muon collider

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    Precise determinations of the masses of the WW boson and of the top quark could stringently test the radiative structure of the Standard Model (SM) or provide evidence for new physics. We analyze the excellent prospects at a muon collider for measuring MWM_W and mtm_t in the W+WW^+W^- and ttˉt\bar t threshold regions. With an integrated luminosity of 10 (100) fb1^{-1}, the WW-boson mass could be measured to a precision of 20 (6) MeV, and the top-quark mass to a precision of 200 (70) MeV, provided that theoretical and experimental systematics are understood. A measurement of Δmt=200\Delta m_t=200 MeV for fixed MWM_W would constrain a 100 GeV SM Higgs mass within about ±2\pm 2 GeV, while ΔMW=6\Delta M_W=6 MeV for fixed mtm_t would constrain mhm_h to about ±10\pm 10 GeV.Comment: 27 pages, 11 figures, postscript file available via anonymous ftp://ucdhep.ucdavis.edu/han/mumu/mwmt.p
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