520 research outputs found
The Effectiviness of Ketapang (Terminalia Cattapa L.) Leave Extract for the Treatment of Aeromonas Salmonicida Infection in Catfish (Pangasioniodon Hypophthalmus)
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
Top quark production in the process 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
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
QCD Correction to Neutralino Annihilation Process and Dark Matter Density in Supersymmetric Models
We calculate QCD correction to the neutralino annihilation cross section into
quark anti-quark final state and discuss its implications to the calculation of
neutralino relic density. We see that the QCD correction enhances the
pair-annihilation cross section by O(10 %) when final-state quarks are
non-relativistic. Consequently, when the lightest neutralinos dominantly
annihilate into a t\bar{t} pair, the relic density of the lightest neutralino
is significantly affected by the QCD correction, in particular when the
lightest-neutralino mass is close to the top-quark mass.Comment: 19 pages, 5 figure
Final-State Interactions in e^+e^- -> t\bar{t} -> b l^+ \nu \bar{b} W^- Near Top Quark Threshold
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
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
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
We apply the Green function formalism for 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 partial wave. We compare the results on the total cross
section, top quark intrinsic momentum distributions and on the energy spectra
of 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
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
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