Optimal pricing and lot-sizing decisions under Weibull distribution deterioration and trade credit policy

In this paper, we consider the problem of simultaneous determination of retail price and lot-size (RPLS) under the assumption that the supplier offers a fixed credit period to the retailer. It is assumed that the item in stock deteriorates over time at a rate that follows a two-parameter Weibull distribution and that the price-dependent demand is represented by a constant-price-elasticity function of retail price. The RPLS decision model is developed and solved analytically. Results are illustrated with the help of a base example. Computational results show that the supplier earns more profits when the credit period is greater than the replenishment cycle length. Sensitivity analysis of the solution to changes in the value of input parameters of the base example is also discussed

Modelling of photonic wire Bragg Gratings

Some important properties of photonic wire Bragg grating structures have been investigate. The design, obtained as a generalisation of the full-width gap grating, has been modelled using 3D finite-difference time-domain simulations. Different types of stop-band have been observed. The impact of the grating geometry on the lowest order (longest wavelength) stop-band has been investigated - and has identified deeply indented configurations where reduction of the stop-bandwidth and of the reflectivity occurred. Our computational results have been substantially validated by an experimental demonstration of the fundamental stop-band of photonic wire Bragg gratings fabricated on silicon-on-insulator material. The accuracy of two distinct 2D computational models based on the effective index method has also been studied - because of their inherently much greater rapidity and consequent utility for approximate initial designs. A 2D plan-view model has been found to reproduce a large part of the essential features of the spectral response of full 3D models

High-Energy Radiation from Pulsars : A Three Dimensional Model Approach

We suggest that some observational features of high-energy radiation from pulsars should be explained in terms of three dimensional geometric models, e.g. the phase-resolved X-ray and $\gamma$-ray spectra and the energy dependent light curves from various pulsars. In this paper, we present a three dimensional pulsar outer-magnetospheric gap model to explain these observational features. The outer-magnetospheric gap is proposed to form near the null charged surface and extend toward the light cylinder. The other two geometric dimensions of the outer-magnetospheric gap, i.e. the vertical size and the azimuthal extension can be determined self-consistently. We apply this model to explain the observed phase-dependent spectra and the energy-dependent light curves of various pulsars.Comment: 13 pages, 9 figure

Experimental demonstration of intermodal dispersion in a two-core optical fiber

The recent prediction that intermodal dispersion can play a significant role in pulse evolution in a two-core optical fiber was confirmed experimentally. A picosecond pulse at 1.548µm launched into one core of a meters-long two-core fiber was found to come out of either core of the fiber as two temporally separate pulses. By measuring the time delay between these two pulses, the intermodal dispersion in the fiber was estimated to be 1.13ps/m, in good agreement with theory

(47171) 1999 TC36, A Transneptunian Triple

We present new analysis of HST images of (47171) 1999 TC36 that confirm it as a triple system. Fits to the point-spread function consistently show that the apparent primary is itself composed of two similar-sized components. The two central components, A1 and A2, can be consistently identified in each of nine epochs spread over seven years of time. In each instance the component separation, ranging from 0.023+/-0.002 to 0.031+/-0.003 arcsec, is roughly one half of the Hubble Space Telescope's diffraction limit at 606 nm. The orbit of the central pair has a semi-major axis of a~867 km with a period of P~1.9 days. These orbital parameters yield a system mass that is consistent with Msys = 12.75+/-0.06 10^18 kg derived from the orbit of the more distant secondary, component B. The diameters of the three components are dA1= 286(+45,-38) km, dA2= 265(+41,-35 km and dB= 139(+22,-18) km. The relative sizes of these components are more similar than in any other known multiple in the solar system. Taken together, the diameters and system mass yield a bulk density of p=542(+317,-211) kg m^-3. HST Photometry shows that component B is variable with an amplitude of >=0.17+/-0.05 magnitudes. Components A1 and A2 do not show variability larger than 0.08+/-0.03 magnitudes approximately consistent with the orientation of the mutual orbit plane and tidally-distorted equilibrium shapes. The system has high specific angular momentum of J/J'=0.93, comparable to most of the known Transneptunian binaries.Comment: 16 pages, 8 figures, 6 tables. Accepted to Icaru

B --> Phi K_S and Supersymmetry

The rare decay B --> Phi K_S is a well-known probe of physics beyond the Standard Model because it arises only through loop effects yet has the same time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible explanations, including contributions mediated by gluino loops and by Higgs bosons. Chirality-preserving LL and RR gluino contributions are generically small, unless gluinos and squarks masses are close to the current lower bounds. Higgs contributions are also too small to explain a large asymmetry if we impose the current upper limit on B(B_s --> mu mu). On the other hand, chirality-flipping LR and RL gluino contributions can provide sizable effects and while remaining consistent with related results in B --> Psi K_S, Delta M_s, B --> X_s gamma and other processes. We discuss how the LR and RL insertions can be distinguished using other observables, and we provide a string-based model and other estimates to show that the needed sizes of mass insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions of other recent works on this topic. Added discussions & plots for gluino mass dependence and effects of theoretical uncertaintie

Two-Loop Neutrino Mass Generation through Leptoquarks

We present a new model of radiative neutrino mass generation wherein TeV scale leptoguark scalars induce tiny neutrino masses as two-loop radiative corrections. The neutrino oscillation parameter \sin^2\theta_{13} is predicted to be close to the current experimental limit within the model. Rare lepton flavor violating processes mediated by leptoquarks have an interesting pattern: \mu -> e \gamma$ may be suppressed, while \mu -> 3 e and \mu-e conversion in nuclei are within reach of the next generation experiments. New CP violating contributions to B_s- \bar{B}_s mixing via leptoquark box diagrams are in a range that can explain the recently reported discrepancy with the standard model. D_s^- -> \ell^- \nu decays mediated by leptoquarks brings theory and experiment closer, removing an observed 2 sigma anomaly. Muon g-2 receives new positive contributions, which can resolve the discrepancy between theory and experiment. The leptoquarks of the model are accessible to the LHC, and their decay branching ratios probe neutrino oscillation parameters.Comment: 30 pages in LaTeX, 10 eps figures, references added, expanded discussion on B_s mixin

Scale dependence of the quark masses and mixings: leading order

We consider the Renormalization Group Equations (RGE) for the couplings of the Standard Model and its extensions. Using the hierarchy of the quark masses and of the Cabibbo-Kobayashi-Maskawa (CKM) matrix our argument is that a consistent approximation for the RGE should be based on the parameter $\lambda= |\hat{V}_{ud}| \approx0.22$. We consider the RGE in the approximation where we neglect all the relative terms of the order $\sim\lambda^{4}$ and higher. Within this approximation we find the exact solution of the evolution equations of the quark Yukawa couplings and of the vacuum expectation value of the Higgs field. Then we derive the evolution of the observables: quark masses, CKM matrix, Jarlskog invariant, Wolfenstein parameters of the CKM matrix and the unitarity triangle. We show that the angles of the unitarity triangle remain constant. This property may restrict the possibility of new symmetries or textures at the grand unification scale.Comment: 15 pages, 4 figures, author of one reference adde