152 research outputs found
Rapapport's broth, a better enrichment medium in the identification of Salmonella from processed frog legs
Live clams (Villorita cyprinoides) collected from their natural beds were packed in different ways like dry pack, tray pack, in oxygenated water (wet pack) and depurated samples in wet pack. It was found that the packaging in l kg lots in 200 gauge polythene bags with oxygen at a temperature of 20°C could keep them live for 4 days. In tray pack without oxygen and water they can be kept alive for 3 days at 20°C. Temperature seems to be the critical factor in the transportation of live clams. At room temperature both dry and wet pack can be kept for 24 h only. Depuration technique does not appear to be useful in prolonging the storage life of clams in live condition as percentage mortality is more at 48 h both at 20°C and room temperature compared to the non-depurated samples
Large-Eddy simulation of pulsatile blood flow
Large-Eddy simulation (LES) is performed to study pulsatile blood flow through a 3D model of arterial stenosis. The model is chosen as a simple channel with a biological type stenosis formed on the top wall. A sinusoidal non-additive type pulsation is assumed at the inlet of the model to generate time dependent oscillating flow in the channel and the Reynolds number of 1200, based on the channel height and the bulk velocity, is chosen in the simulations. We investigate in detail the transition-to-turbulent phenomena of the non-additive pulsatile blood flow downstream of the stenosis. Results show that the high level of flow recirculation associated with complex patterns of transient blood flow have a significant contribution to the generation of the turbulent fluctuations found in the post-stenosis region. The importance of using LES in modelling pulsatile blood flow is also assessed in the paper through the prediction of its sub-grid scale contributions. In addition, some important results of the flow physics are achieved from the simulations, these are presented in the paper in terms of blood flow velocity, pressure distribution, vortices, shear stress, turbulent fluctuations and energy spectra, along with their importance to the relevant medical pathophysiology
Electrically tunable VO2-metal metasurface for mid-infrared switching, limiting, and nonlinear isolation
We demonstrate an electrically controlled metal-VO2 metasurface for the
mid-wave infrared that simultaneously functions as a tunable optical switch, an
optical limiter with a tunable limiting threshold, and a nonlinear optical
isolator with a tunable operating range. The tunability is achieved via Joule
heating through the metal comprising the metasurface, resulting in an
integrated optoelectronic device. As an optical switch, the device has an
experimental transmission ratio of ~100 when varying the bias current.
Operating as an optical limiter, we demonstrated tunability of the limiting
threshold from 20 mW to 180 mW of incident laser power. Similar degrees of
tunability are also achieved for nonlinear optical isolation, which enables
asymmetric (nonreciprocal) transmission.Comment: Main text + supplementar
On Measuring Violation in Neutral -meson Decays at the Resonance
Within the standard model we carry out an analysis of -violating
observables in neutral -meson decays at the resonance. Both
time-dependent and time-integrated asymmetries are calculated, without
special approximations, to meet various possible measurements at symmetric and
asymmetric factories. We show two ways to distinguish between
direct and indirect -violating effects in the -eigenstate channels such
as and .
Reliable knowledge of the Cabibbo-Kobayashi-Maskawa phase and angles can in
principle be extracted from measurements of some non--eigenstate channels,
e.g. and
, even in the presence of significant
final-state interactions.Comment: Latex file 13 pages, CERN-TH.7194/94 and PVAMU-HEP-94-2 (Phys. Lett.
B328 (1994) 477). (A few minor typing errors have been corrected.
Saturation in diffractive deep inelastic eA scattering
In this paper we investigate the saturation physics in diffractive deep
inelastic electron-ion scattering. We estimate the energy and nuclear
dependence of the ratio and predict the x_{\pom}
and behavior of the nuclear diffractive structure function
. Moreover, we analyze the ratio
,
which probes the nuclear dependence of the structure of the Pomeron. We show
that saturation physics predicts that approximately 37 % of the events observed
at eRHIC should be diffractive.Comment: 15 pages, 7 figures. Version to be published in the European Physical
Journal
Final State Interactions in and Decays
We analyze final state strong interaction effects in and decays using the Regge model. We find that, due to the smallness of
the contributions from the non-leading Regge trajectories (, ,
etc.), final state interaction phases are small if the Pomeron coupling to the
charm quark is suppressed in comparison to lighter quarks. Our conclusion is
that for decays into states containing charm, final state interaction
effects should play a minor role.Comment: 10 pages, LaTeX, accepted for Physics Letters
Neutron Electric Dipole Moment in the Minimal Supersymmetric Standard Model
Neutron electric dipole moment (EDM) due to single quark EDM and to the
transition EDM is calculated in the minimal supersymmetric standard model.
Assuming that the Cabibbo-Kobayashi-Maskawa matrix at the grand unification
scale is the only source of CP violation, complex phases are induced in
parameters of soft supersymmetry breaking at low energies. Chargino one-loop
diagram is found to give the dominant contribution of the order of
cm for quark EDM, assuming the light chargino
mass and the universal scalar mass to be GeV and GeV, respectively.
Therefore the neutron EDM in this class of model is difficult to measure
experimentally. Gluino one-loop diagram also contributes due to the flavor
changing gluino coupling. The transition EDM is found to give dominant
contributions for certain parameter regions.Comment: 27 pages, LaTeX file with figures, several misprints in pp. 7, 14, 20
and 24 are correcte
Multi-wavelength observations of an unusual impulsive flare associated with CME
We present the results of a detailed analysis of multi-wavelength
observations of a very impulsive solar flare 1B/M6.7, which occurred on 10
March, 2001 in NOAA AR 9368 (N27 W42). The observations show that the flare is
very impulsive with very hard spectrum in HXR that reveal non-thermal emission
was most dominant. On the other hand this flare also produced type II radio
burst and coronal mass ejections (CME), which are not general characteristics
for impulsive flares. In H we observed the bright mass ejecta (BME)
followed by drak mass ejecta (DME). Based on the consistence of the onset times
and direction of BME and CME, we conclude that these two phenomena are closely
associated. It is inferred that the energy build-up took place due to
photospheric reconnection between emerging positive parasitic polarity and
predominant negative polarity, which resulted as a consequence of flux
cancellation. The shear increased to due to further emergence of
positive parasitic polarity causing strongly enhanced cancellation of flux. It
appears that such enhanced magnetic flux cancellation in a strongly sheared
region triggered the impulsive flare.Comment: 14 pages, 8 Figures, Accepted for the publication in Solar Physic
Phenomenology of Heavy Meson Chiral Lagrangians
The approximate symmetries of Quantum ChromoDynamics in the infinite heavy
quark () mass limit () and in the chiral limit for the
light quarks () can be used together to build up an
effective chiral lagrangian for heavy and light mesons describing strong
interactions among effective meson fields as well as their couplings to
electromagnetic and weak currents, including the relevant symmetry breaking
terms. The effective theory includes heavy () mesons of both negative
and positive parity, light pseudoscalars, as well as light vector mesons. We
summarize the estimates for the parameters entering the effective lagrangian
and discuss in particular some phenomenologically important couplings, such as
. The hyperfine splitting of heavy mesons is discussed in
detail. The effective lagrangian allows for the possibility to describe
consistently weak couplings of heavy () to light ( etc.) mesons. The method has however its own limitations, due to the
requirement that the light meson momenta should be small, and we discuss how
such limitations can be circumvented through reasonable ansatz on the form
factors. Flavour conserving (e. g. ) and flavour changing
(e. g. ) radiative decays provide another field of
applications of effective lagrangians; they are discussed together with their
phenomenological implications. Finally we analyze effective lagrangians
describing heavy charmonium- like () mesons and their strong and
electromagnetic interactions. The role of approximate heavy quark symmetries
for this case and the phenomenological tests of these models are also
discussed.Comment: 92 pages, LaTeX, 17 figures, to appear in Physics Reports, page size
shortened to fit american forma
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