Magneto-optical transport properties of monolayer phosphorene

The electronic properties of monolayer phosphorene are exotic due to its puckered structure and large intrinsic direct band gap. We derive and discuss its band structure in the presence of a perpendicular magnetic field. Further, we evaluate the magneto-optical Hall and longitudinal optical conductivities, as functions of temperature, magnetic field, and Fermi energy, and show that they are strongly influenced by the magnetic field. The imaginary part of the former and the real part of the latter exhibit regular {\it interband} oscillations as functions of the frequency $\omega$ in the range $\hslash\omega\sim 1.5-2$ eV. Strong {\it intraband} responses in the latter and week ones in the former occur at much lower frequencies. The magneto-optical response can be tuned in the microwave-to-terahertz and visible frequency ranges in contrast with a conventional two-dimensional electron gas or graphene in which the response is limited to the terahertz regime. This ability to isolate carriers in an anisotropic structure may make phosphorene a promising candidate for new optical devices.Comment: 7 pages and 8 figure

Multi-parameter approach to R-parity violating SUSY couplings

We introduce and implement a new, extended approach to placing bounds on trilinear R-parity violating couplings. We focus on a limited set of leptonic and semi-leptonic processes involving neutrinos, combining multidimensional plotting and cross-checking constraints from different experiments. This allows us to explore new regions of parameter space and to relax a number of bounds given in the literature. We look for qualitatively different results compared to those obtained previously using the assumption that a single coupling dominates the R-parity violating contributions to a process (SCD). By combining results from several experiments, we identify regions in parameter space where two or more parameters approach their maximally allowed values. In the same vein, we show a circumstance where consistency between independent bounds on the same combinations of trilinear coupling parameters implies mass constraints among slepton or squark masses. Though our new bounds are in most cases weaker than the SCD bounds, the largest deviations we find on individual parameters are factors of two, thus indicating that a conservative, order of magnitude bound on an individual coupling is reliably estimated by making the SCD assumption.Comment: 30 pages, 8 figures, 2 tables. Typos fixed, two references added and references updated. Eq. (41) removed, Eq. (40) and text modified. Published versio

Withania Somnifera: Correlation of Phytoconstituents with Hypolipidemic and Cardioprotective Activities

Withania somnifera (WS) (Dunal) or Ashwagandha is a well-known hypolipidemic herb and antioxidant. In this study, 75% ethanolic extract of WS is attempted to evaluate the cardioprotective activity of isoproterenol-induced cardiotoxicity and hypolipidemic activity in Triton WR 1339-induced hyperlipidemia. In addition, phytochemical evaluation of the same extracts analyzed by gas chromatography–mass spectrometer (GC–MS). This study found that 7 days of therapy with WS extracts at 1000 mg/kg b.wt. reduced cholesterol by 76%, low-density lipoprotein (LDL) by 71%, and TAG by 12% (P < 0.05). Furthermore, it can significantly reduce cholesterol and LDL levels (P < 0.05). Similarly, the use of 50 mg/kg b.wt. of WS extract showed a cardioprotective effect against isoproterenol-induced cardiac toxic rats. The antioxidants glutathione, glutathione peroxidase, and catalase are increased in WS extract (P < 0.05), whereas the release of cardiac indicators in heart tissue is reduced (P < 0.05). Furthermore, a 30-day treatment with WS also reduced triacylglycerol in isoprenaline-induced cardiotoxic rats. GC–MS analysis of the methanol fraction of the Ashwagandha 70% ethanolic extract showed the presence of higher concentrations of fatty acids. In conclusion, WS showed hypolipidemic and cardioprotective activities in diseased animals induced by isoproterenol and Triton WR 1339

Lepton Polarization Asymmetry in B l l(bar) decays in R-parity violating Minimal Supersymmetric Standard Model

We study the implication of R-parity violating Rp Minimal Supersymmetric Standard Model (MSSM) model in lepton polarization asymmetry ALP in B l l(bar) decays . The analysis show that the ALP is significant in a certain phenomenological parametric region of Yukawa couplings. We have also placed indirect bounds on Lambda' lambda couplings as obtained from B t t(bar).Comment: 6 pages, 4 figures Changes of notation in Eq(8-11,17-19),Eq.20 adde

The use of a Digital Image Correlation method with a low-speed camera to obtain characteristics of surface velocity and sound radiation for automotive-type panels

The perceived quality of a vehicle is highly influenced by the driver s experience of the vehicle interior noise. Significant research has been carried out all over the world in order to characterize structural and acoustic characteristics, to control and minimize the vibration and noise from entering or emitted to vehicles. Designers require tools to inform them whether the design changes are positive or negative in terms of the noise and vibration, and to help validate numerical finite element models of complicated structures. This research explores the use of Digital Image Correlation (DIC) equipment and methods by using a relatively inexpensive low speed camera to investigate the structural-acoustics characteristics applied to automotive-type panels, where otherwise a highly expensive and sensitive scanning laser Doppler vibrometer would be required. Experimental measurements based on Noise Path Analysis (NPA) have been carried out and theoretical and numerical predictions on sound radiation behaviour have been developed. The prediction values have been evaluated and validated with experimental measurements. Using a DIC measurement method to obtain spatially averaged surface velocities, averaged over several cycles through phase locking, the results for the sound power predictions for the selected mode shape and the resonance frequencies provided a good estimation when comparing with the experiment. For mode (1, 1), the sound power prediction was 80.9 dB while the measured one was 77.2 dB with a difference of 3.7.while the other selected modes showed a difference not more than 3.7 dB. It was within the range suggested by considering the mathematical simplification approach during the prediction development stage. To conclude, it was found that the prediction of sound power throughout the vibrating structure can provide a good accuracy by using the DIC method Therefore, it can be an alternative technique to evaluate the sound radiation for characterizing one of the structural propertie