464 research outputs found
NLL Corrections for B-Meson Radiative Exclusive Decays
We calculate the next-to-leading corrections to the branching ratio of
exclusive decay. The renormalization scale dependence is
reduced compared to the leading logarithmic result but there remains a
dependence on a cutoff parameter of the hadronic model. The calculated
corrections increase the predicted branching ratio by about 10%, but it remains
in agreement with the experimental value.Comment: 16 pages, 8 figure
The Antioxidant and Antimicrobial of Syrian Sumac (Rhus coriaria) Fruit Extracts
This study aimed at assaying the antioxidant activities of Syrian sumac (Rhus coriaria) . The proximate analysis revealed that Syrian sumac contains higher percentage of fat , carbohydrate , protein and ash 18.74 , 71.21 , 4.69 and 2.93 % respectively . All extracts 1,4 and 2 showed antioxidant effects compared with ?- tocopherol . But the antioxidant effects of all extracts was low compared with BHT . While the extracts 3 has no effect in preventing lipid peroxidation 37.87% at 5 mg / ml after 1 day . The antimicrobial activity of Rhus coriaria extracts were tested against six strains including three Gram –positive and three Gram –negative . Bacillus subtilis was found to be the most sensitive Gram –positive with MIC of 0.5 mg / ml , while Gram –negative bacteria were affected by higher concentrations of sumac extracts ranging 10-20 mg / ml . Among bacteria , the inhibitory effects was increased with the increase of R . coriaria fruit extracts concentration from 0.1 to 20 mg / ml . The findings demonstrate that sumac can be used as a natural antioxidant and antimicrobial
CP Asymmetry for Inclusive Decay in the Minimal Supersymmetric Standard Model
We study the inclusive rare decay in the supergravity
inspired Minimal Supersymmetric Standard Model and compute the CP-asymmetry in
the decay rates. We show that there exist two phenomenologically acceptable
sets of SUSY parameters: for one set the CP-asymmetry has the same (positive)
sign as in the Standard Model and lies in the range (5-45)% while for the other
set it is negative with values within -(2-21)%.Comment: 15 pages, uses axodraw.st
Complete NNLO QCD Analysis of B -> X_s l^+ l^- and Higher Order Electroweak Effects
We complete the next-to-next-to-leading order QCD calculation of the
branching ratio for B -> X_s l^+ l^- including recent results for the
three-loop anomalous dimension matrix and two-loop matrix elements. These new
contributions modify the branching ratio in the low-q^2 region, BR_ll, by about
+1% and -4%, respectively. We furthermore discuss the appropriate normalization
of the electromagnetic coupling alpha and calculate the dominant higher order
electroweak effects, showing that, due to accidental cancellations, they change
BR_ll by only -1.5% if alpha(mu) is normalized at mu = O(m_b), while they shift
it by about -8.5% if one uses a high scale normalization mu = O(M_W). The
position of the zero of the forward-backward asymmetry, q_0^2, is changed by
around +2%. After introducing a few additional improvements in order to reduce
the theoretical error, we perform a comprehensive study of the uncertainty. We
obtain BR_ll(1 GeV^2 <= q^2 <= 6 GeV^2) = (1.57 +- 0.16) x 10^-6 and q_0^2 =
(3.76 +- 0.33) GeV^2 and note that the part of the uncertainty due to the
b-quark mass can be easily reduced.Comment: 26 pages, 7 figures; v5: corrected normalisation in Eq. (5),
numerical results unchange
The efficiency of biosynthesized Zinc oxide nanoparticles by Fusarium sp. against Saprolegnia parasitica isolated from common carp eggs in fish hatchery
Saprolegnia spp. infect common carp (Cyprinus carpio L.) eggs in hatcheries. Therefore, this study aimed to evaluate the antifungal effect of biosynthesized zinc oxide nanoparticles (ZnNPs) against Saprolegnia spp. as an eco-friendly treatment. Biosynthesized ZnNPs were characterized using atomic force microscope (AFM), size distributor and Ultra Violate-Visible spectrometer (Uv-Vis), and Scanning Electron Microscope (SEM). Biosynthesized (ZnNPs) had a spherical shape with diameters ranging 10-70 nm. Antifungal activity was tested by fungal radial growth inhibition on corn meal agar. The highest concentration of 100 ppm of ZnNPs showed a remarkable inhibition rate of 79% against Saprolegnia spp., demonstrating similar efficiency as the positive control i.e. malachite green in the inhibition percentage rate of fungal growth. This study showed that biosynthesized zinc oxide nanoparticles had a significant antifungal effect (P<0.05) and can be used as an alternative option to control Saprolegnia spp. in fish hatcheries
Calculation of two-loop virtual corrections to b --> s l+ l- in the standard model
We present in detail the calculation of the virtual O(alpha_s) corrections to
the inclusive semi-leptonic rare decay b --> s l+ l-. We also include those
O(alpha_s) bremsstrahlung contributions which cancel the infrared and mass
singularities showing up in the virtual corrections. In order to avoid large
resonant contributions, we restrict the invariant mass squared s of the lepton
pair to the range 0.05 < s/mb^2 < 0.25. The analytic results are represented as
expansions in the small parameters s/mb^2, z = mc^2/mb^2 and s/(4 mc^2). The
new contributions drastically reduce the renormalization scale dependence of
the decay spectrum. For the corresponding branching ratio (restricted to the
above s-range) the renormalization scale uncertainty gets reduced from +/-13%
to +/-6.5%.Comment: 41 pages including 9 postscript figures; in version 2 some typos and
inconsistent notation correcte
Новый переносчик вируса Х картофеля - гриб Phytophthora infestans (Mont.) de Bary
Prove participation in the dissemination of the potato virus X zoospores of the fungus Phytophthora infestans. The minimum period for the acquisition virofornos was 12 hours of infection 72 hours after exposure to suspensions, zoospores at a donor within 24 hours, the efficiency of transmission increased. We found that the activity of transmission varies depending on the infected variety and soil temperature. And also influence of nitrates on growth and on number zoospores fungi Ph. infestans.В статье рассматриваются доказательства участия зооспор гриба Phytophthora infestans в распространении Х вируса картофеля. Также рассматриваются условия передачи вируса Х картофеля. Минимальный период времени для приобретения вирофорности составил 12 часов, для передачи инфекции - 72 часа; после экспозиции суспензии зооспор на доноре в течение 24 часов эффективность передачи возрастала. Найдено, что активность передачи и скорость распространения инфекции варьируют в зависимости от инфицируемого сорта и температуры почвы. В лабораторных экспериментах показано, что содержание нитратов в среде влияет на рост гриба Ph. infestans и на численность образующихся зооспор
More Model-Independent Analysis of b->s Processes
We study model-independently the implications of non-standard scalar and
pseudoscalar interactions for the decays b ->s gamma, b -> s g, b -> s l^+l^-
(l=e,mu) and B_s -> mu^+ mu^-. We find sizeable renormalization effects from
scalar and pseudoscalar four-quark operators in the radiative decays and at
O(alpha_s) in hadronic b decays. Constraints on the Wilson coefficients of an
extended operator basis are worked out. Further, the ratios R_H = BR(B -> H
mu^+ mu^-)/BR(B -> H e^+ e^-), for H=K^(*), X_s, and their correlations with
B_s -> mu^+ mu^- decay are investigated. We show that the Standard Model
prediction for these ratios defined with the same cut on the dilepton mass for
electron and muon modes, R_H= 1 + O(m^2_mu/m^2_b), has a much smaller
theoretical uncertainty (<1%) than the one for the individual branching
fractions. The present experimental limit R_K < 1.2 puts constraints on scalar
and pseudoscalar couplings, which are similar to the ones from current data on
BR(B_s -> mu^+ mu^-). We find that new physics corrections to R_{K*} and
R_{X_s} can reach 13% and 10%, respectively.Comment: 28 pages, 6 figures; Table 1 updated, two refs added (to appear in
PRD
Lepton polarization asymmetry and forward backward asymmetry in exclusive B->K_1 tau^(+)tau^(-) decay in universal extra dimension scenario
Decay rate, forward-backward asymmetry and polarization asymmetries of final
state leptons in B-> K_{1}tau ^{+}tau ^{-}, where K_{1} is the axial vector
meson, are calculated in Standard Model and in the universal extra dimension
(UED) model. The sensitivity of the observables on the compactification radius
, the only unknown paramter in UED model, is studied. Finally, the helicity
fractions of the final state K_{1} are calculated and their dependence on the
compactification radius is discussed. This analysis of helicity fraction is
briefly extended to B->K^{*}l ^{+}l ^{-}(l =e,mu) and compared with the other
approaches exist in the literatureComment: 19 pages, 6 figure
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