849 research outputs found
Decay of bound states in a sine-Gordon equation with double well potentials
We consider a spatially inhomogeneous sine-Gordon equation with a double-well potential, describing long Josephson junctions with phase-shifts. We discuss the interactions of symmetric and antisymmetric bound states in the system. Using a multiple scale expansion, we show that the modes decay algebraically in time due to the energy transfer from the discrete to the continuous spectrum. In particular, exciting the two modes at the same time yields an increased decay rate. An external time-periodic drive is shown to sustain symmetric state, while it damps the antisymmetric one
Boundary Effects in Local Inflation and Spectrum of Density Perturbations
We observe that when a local patch in a radiation filled Robertson-Walker
universe inflates by some reason, outside perturbations can enter into the
inflating region. Generally, the physical wavelengths of these perturbations
become larger than the Hubble radius as they cross into the inflating space and
their amplitudes freeze out immediately. It turns out that the corresponding
power spectrum is not scale invariant. Although these perturbations cannot
reach out to a distance inner observer shielded by a de Sitter horizon, they
still indicate a curious boundary effect in local inflationary scenarios.Comment: 11 pages, 8 figures, revtex4, v4: minor typos corrected, twocolumn
versio
Probing the Solute-Solvent Interaction of an Azo-Bonded Prodrug in Neat and Binary Media: Combined Experimental and Computational Study
Preferential solvation has significant importance in interpreting the molecular physicochemical properties of wide spectrum of materials in solution. In this work, the solute-solvent interaction of pro-drug Sulfasalazine (SSZ) in neat and binary media was investigated experimentally and computationally. The solute-solvent interactions of interest were spectrophotometrically probed and computationally investigated for providing insights concerning the molecular aspects of SSZ:media interaction. Experimentally, the obtained results in 1,4-dioxane:water binary mixture demonstrated a dramatic non-linear changes in the spectral behavior of SSZ indicative of the dependency of its molecular behaviors on the compositions of the molecular microenvironment in the essence of solute-solvent interaction. Computationally, geometry optimization and simulation of the absorption spectra of SSZ in media of interest were performed employing DFT and TD-DFT methods, respectively, where the solvent effects on the absorption were examined implicitly using IEFPCM method. Obtained results revealed a nonpolar nature of the molecular orbitals that are directly involved in the SSZ:medium interaction. As in good correspondence with the experimental results, these simulations demonstrated that these orbitals are of non-polar nature and hence minimally affected by polarity of the media and in turn favoring the non-polar molecular environments. On the other hand, the molecular origin of SSZ:media interaction was demonstrated explicitly through complexation of SSZ with water molecules revealing a cooperative hydrogen bonding stabilization with an average length of 1.90 Å. The findings of this work demonstrate the significance of the preferential solvation and composition of the molecular microenvironment on the physicochemical properties of molecules of pharmaceutical importance. © 2019, The Author(s).Scopu
The NNLO non-singlet QCD analysis of parton distributions based on Bernstein polynomials
A non-singlet QCD analysis of the structure function up to NNLO is
performed based on the Bernstein polynomials approach. We use recently
calculated NNLO anomalous dimension coefficients for the moments of the
structure function in scattering. In the fitting procedure, Bernstein
polynomial method is used to construct experimental moments from the
data of the CCFR collaboration in the region of which is inaccessible
experimentally. We also consider Bernstein averages to obtain some unknown
parameters which exist in the valence quark densities in a wide range of
and . The results of valence quark distributions up to NNLO are in good
agreement with the available theoretical models. In the analysis we determined
the QCD-scale MeV (LO), 259 MeV (NLO)
and 230 MeV (NNLO), corresponding to LO,
NLO and NNLO. We compare our
results for the QCD scale and the with those obtained from
deep inelastic scattering processes.Comment: 20 pages, 7 figures, published in JHE
The exclusive B_s -> phi mu+ mu- process in a constituent quark model
We consider the exclusive B_s -> phi mu+ mu- process in the standard model
using a constituent quark loop model approach together with a simple
parameterization of the quark dynamics. The model allows to compute the decay
form factors and therefore can give predictions for the decay rates, the
invariant mass spectra and the asymmetries. This process is suppressed in the
standard model but can be enhanced if new physics beyond the standard model is
present, such as flavor-violating supersymmetric models. It constitutes
therefore an interesting precision test of the standard model at forthcoming
experiments.Comment: 17 pages, 6 figures, 5 tables, LaTeX; minor changes to the
introduction, table III and figure 3. Few references adde
Improve the Process of Enhancing Oil Recovery (EOR) by Applying Nanomagnetic Cobalt Ferrite Nanoparticles
In this paper we reported nano-crystalline cobalt ferrite powders were synthesized using co-precipitation method at 600 °C, 700 °C and 800 °C. The structural, morphological and magnetic properties of the powders were investigated by x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Infrared spectral analysis data between 200 and 1000 cm-1 defined the intrinsic cation vibrations of the characteristic spinel structure system. The saturation magnetization (Ms) and coercivity (Hc) of the CoFe2O4 were found to be in the range of 94-33 emu/g, which is still in the range of hard ferrite. The observed variation in saturation magnetization, coercivity and remanence magnetization as a function of increasing the temperature and grain size of samples. From this point of view, nano-scale size of nanoparticles makes them efficient for using in borehole stability maintaining for enhancing oil and gas recovery efficiency improvement. The large value of magnetic pressure (-2.95699) are expected to be useful in oil recovery applications. It has also been found that the choice of nanoparticles for application in oil recovery depends on nature, magnetic and electric properties of the reservoir rock
Wandering spleen: a unique cause of acute abdomen
We present the case of a 16-year-old boy presented with 2-week episode of worsening lower abdominal pain. Clinically, there was a tender palpable mass on the suprapubic region. Ultrasonography showed an absent spleen at its usual area, instead suprapubic mass suggestive of ectopic spleen was identified. An emergency laparotomy revealed a congested spleen in the pelvic cavity. Splenectomy was undertaken as it was non-viable. The patient was discharged uneventfully with triple vaccinations. We describe this unique entity with its literature review. (Folia Morphol 2018; 77, 2: 400–402
Optical activity of neutrinos and antineutrinos
Using the one-loop helicity amplitudes for low-energy
and scattering in the standard model with
massless neutrinos, we study the optical activity of a sea of neutrinos and
antineutrinos. In particular, we estimate the values of the index of refraction
and rotary power of this medium in the absence of dispersion.Comment: Additional reference
Seroprevalence of infectious bursal disease virus antibodies in some species of poultry in Maiduguri, Nigeria
This study was aimed at determining the antibodies of IBDV in some poultry species in Maiduguri, Nigeria. A total of 944 serum samples were collected from village chickens, broilers, layers, ducks, turkeys and geese in Maiduguri and tested for IBDV antibodies using inzyme linked Immunosorbent assay (ELISA) and a seroprevalence of 46.6% was recorded. The species distribution showed that 33.4% of local chickens (134/401), 67.3% of layers (35/52), 50.8% of broilers (159/313), 60.6% of turkeys (77/127), 65.5% of ducks (19/29) and 72.7% of geese (16/22) sampled were positive for IBDV antibodies. Males showed a seroprevalence of 70% while females recorded 30%. IBDV seropositive sera showed that samples from broilers reacted with 31.5% middle OD values and turkeys with 9.4% middle OD values. Samples from other species reacted with lower OD values. Samples from other species reacted with lower OD values. Presence of IBDV antibodies in species other than chickens suggested that different bird species might have IBDV and could serve as reservoirs for IBDV transmission. Because of this threat to poultry industry, there is need for continuous surveillance of IBDV in all poultry species so as to institute effective preventive measures against the disease.Keywords: ELISA, Infectious bursal disease virus, IgG, Poultry species, Serum sample
Searching for chiral logs in the static-light decay constant
Using the clover fermion action in unquenched QCD with pion masses as low as
420 MeV, we look for evidence for chiral logs in the static-light decay
constant. There is some evidence for a chiral log term, if the original static
theory of Eichten and Hill is used. However, the more precise data from the
static action of the ALPHA collaboration do not show any evidence for
non-linear dependence of the static-light decay constant on the light quark
mass. We make some comments on the connection between chiral perturbation
theory for decay constants of the pion and static-light meson
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