Firm size and the pre- holiday effect in New Zealand

Using a sample spanning four decades, we document that the pre-holiday effect, one of the most common of the calendar effect anomalies, still exists in the New Zealand market. Contrary to international evidence, the effect appears to have increased over time. Moreover, we find that this effect is inversely related to firm size with the entire effect limited only to small firms, with no pre-holiday price patterns being observed for medium to large firms. The existence of this pre-holiday effect seems to be mainly driven by factors relevant to New Zealand. A search for possible reasons for the persistence of the effect points primarily towards the illiquidity of smaller stocks and the reluctance of small investors to buy prior to major market closures

The weak localization for the alloy-type Anderson model on a cubic lattice

We consider alloy type random Schr\"odinger operators on a cubic lattice whose randomness is generated by the sign-indefinite single-site potential. We derive Anderson localization for this class of models in the Lifshitz tails regime, i.e. when the coupling parameter $\lambda$ is small, for the energies $E \le -C \lambda^2$.Comment: 45 pages, 2 figures. To appear in J. Stat. Phy

Analysis of Residual Stresses in Laser-Shock-Peened and Shot-Peened Marine Steel Welds

Laser peening is now the preferred method of surface treatment in many applications. The magnitude and depth of the compressive residual stress induced by laser peening can be influenced strongly by the number of peen layers (the number of laser hits at each point) and by processing conditions including the use of a protective ablative layer. In this study, residual stresses have been characterized in laser and shot-peened marine butt welds with a particular focus at the fatigue crack initiation location at the weld toe. X-ray diffraction, synchrotron X-ray diffraction, incremental center-hole drilling, and the contour method were used for determination of residual stress. Results showed that the use of ablative tape increased the surface compressive stress, and the depth of compressive stress increased with an increase in number of peening layers. A key result is that variation of residual stress profile across laser peen spots was seen, and the residual stress magnitude varies between the center and edges of the spots

Narrow width of a glueball decay into two mesons

The widths of a glueball decay to two pions or kaons are analyzed in the pQCD framework. Our results show that the glueball ground state has small branching ratio for two-meson decay mode, which is around $10^{-2}$. The predicted values are consistent with the data of $\xi\to\pi\pi, KK$ if $\xi$ particle is a $2^{++}$ glueball. Applicability of pQCD to the glueball decay and comparison with $\chi_{cJ}$ decay are also discussed.Comment: 12 pages, revtex, 2 ps figure

Study of the temperature distribution in Si nanowires under microscopic laser beam excitation

The use of laser beams as excitation sources for the characterization of semiconductor nanowires (NWs) is largely extended. Raman spectroscopy and photoluminescence (PL) are currently applied to the study of NWs. However, NWs are systems with poor thermal conductivity and poor heat dissipation, which result in unintentional heating under the excitation with a focused laser beam with microscopic size, as those usually used in microRaman and microPL experiments. On the other hand, the NWs have subwavelength diameter, which changes the optical absorption with respect to the absorption in bulk materials. Furthermore, the NW diameter is smaller than the laser beam spot, which means that the optical power absorbed by the NW depends on its position inside the laser beam spot. A detailed analysis of the interaction between a microscopic focused laser beam and semiconductor NWs is necessary for the understanding of the experiments involving laser beam excitation of NWs. We present in this work a numerical analysis of the thermal transport in Si NWs, where the heat source is the laser energy locally absorbed by the NW. This analysis takes account of the optical absorption, the thermal conductivity, the dimensions, diameter and length of the NWs, and the immersion medium. Both free standing and heat-sunk NWs are considered. Also, the temperature distribution in ensembles of NWs is discussed. This analysis intends to constitute a tool for the understanding of the thermal phenomena induced by laser beams in semiconductor NWs

Electroweak Radiative Corrections to Associated WH and ZH Production at Hadron Colliders

Higgs-boson production in association with W or Z bosons, p pbar -> WH/ZH + X, is the most promising discovery channel for a light Standard Model Higgs particle at the Fermilab Tevatron. We present the calculation of the electroweak O(alpha) corrections to these processes. The corrections decrease the theoretical prediction by up to 5-10%, depending in detail on the Higgs-boson mass and the input-parameter scheme. We update the cross-section prediction for associated WH and ZH production at the Tevatron and at the LHC, including the next-to-leading order electroweak and QCD corrections, and study the theoretical uncertainties induced by factorization and renormalization scale dependences and by the parton distribution functions.Comment: 32 pages, LaTeX, 21 figures. Uses axodraw.sty and feynarts.sty. Added reference

Theory of magnetically powered jets

The magnetic theory for the production of jets by accreting objects is reviewed with emphasis on outstanding problem areas. An effort is made to show the connections behind the occasionally diverging nomenclature in the literature, to contrast the different points of view about basic mechanisms, and to highlight concepts for interpreting the results of numerical simulations. The role of dissipation of magnetic energy in accelerating the flow is discussed, and its importance for explaining high Lorentz factors. The collimation of jets to the observed narrow angles is discussed, including a critical discussion of the role of `hoop stress'. The transition between disk and outflow is one of the least understood parts of the magnetic theory; its role in setting the mass flux in the wind, in possible modulations of the mass flux, and the uncertainties in treating it realistically are discussed. Current views on most of these problems are still strongly influenced by the restriction to 2 dimensions (axisymmetry) in previous analytical and numerical work; 3-D effects likely to be important are suggested. An interesting problem area is the nature and origin of the strong, preferably highly ordered magnetic fields known to work best for jet production. The observational evidence for such fields and their behavior in numerical simulations is discussed. I argue that the presence or absence of such fields may well be the `second parameter' governing not only the presence of jets but also the X-ray spectra and timing behavior of X-ray binaries.Comment: 29 pages. Publication delays offered the opportunity for further corrections, an expansion of sect 4.2, and one more Fig. To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009

Use of hydrophilic and hydrophobic polymers for the development of controlled release tizanidine matrix tablets

The aim of the present study was to develop tizanidine controlled release matrix. Formulations were designed using central composite method with the help of design expert version 7.0 software. Avicel pH 101 in the range of 14-50% was used as a filler, while HPMC K4M and K100M in the range of 25-55%, Ethylcellulose 10 ST and 10FP in the range of 15 - 45% and Kollidon SR in the range of 25-60% were used as controlled release agents in designing different formulations. Various physical parameters including powder flow for blends and weight variation, thickness, hardness, friability, disintegration time and in-vitro release were tested for tablets. Assay of tablets were also performed as specified in USP 35 NF 32. Physical parameters of both powder blend and compressed tablets such as compressibility index, angle of repose, weight variation, thickness, hardness, friability, disintegration time and assay were evaluated and found to be satisfactory for formulations K4M2, K4M3, K4M9, K100M2, K100M3, K100M9, E10FP2, E10FP9, KSR2, KSR3 & KSR9. In vitro dissolution study was conducted in 900 ml of 0.1N HCl, phosphate buffer pH 4.5 and 6.8 medium using USP Apparatus II. In vitro release profiles indicated that formulations prepared with Ethocel 10 standard were unable to control the release of drug while formulations K4M2, K100M9, E10FP2 & KSR2 having polymer content ranging from 40-55% showed a controlled drug release pattern in the above mentioned medium. Zero-order drug release kinetics was observed for formulations K4M2, K100M9, E10FP2 & KSR2. Similarity test (f2) results for K4M2, E10FP2 & KSR2 were found to be comparable with reference formulation K100M9. Response Surface plots were also prepared for evaluating the effect of independent variable on the responses. Stability study was performed as per ICH guidelines and the calculated shelf life was 24-30 months for formulation K4M2, K100M9 and E10FP2