Desperate housewives: An analysis of the characterisations of female gamblers portrayed in gambling movies in Hong Kong

This article examines portrayals of female gamblers in recent Hong Kong movies. The authors report that the depiction of female gamblers is very different from that of male gamblers in the movies made in the same period. Whereas the male gamblers are pitching a lonely and desperate battle against the evil opponent, the female gamblers portrayed in the movies are housewives or small-time players who gamble only for their personal gain. A general negative overtone in portrayals of female gamblers was interpreted as a reflection of the traditional view that discourages women from gambling. The shift of gambling themes in the Hong Kong movies has been identified to reflect the most salient concerns among Hong Kong residents. Such changes are attributed to particular social and cultural changes in the community

Entanglement control in one-dimensional s=1/2s=1/2 random XY spin chain

The entanglement in one-dimensional random XY spin systems where the impurities of exchange couplings and the external magnetic fields are considered as random variables is investigated by solving the different spin-spin correlation functions and the average magnetization per spin. The entanglement dynamics near particular locations of the system is also studied when the exchange couplings (or the external magnetic fields) satisfy three different distributions(the Gaussian distribution, double-Gaussian distribution, and bimodal distribution). We find that the entanglement can be controlled by varying the strength of external magnetic field and the different distributions of impurities. Moreover, the entanglement of some nearest-neighboring qubits can be increased for certain parameter values of the three different distributions.Comment: 13 pages, 4 figure

Measurement of birefringence for optical recording disk substrates

The birefringence of bare and coated substrates for magneto-optical recording is experimentally investigated using ellipsometry at the wavelengths of 632.8 nm and 780 nm. The rotation and ellipticity of the polarization state of the reflected or transmitted light is measured for different incident angles and different orientations of the incident linear polarization. The measured data is then fitted by a computer program which solves the Maxwell equations for the plane-wave propagation in a multilayer structure and minimizes the error between the measured and calculated data by adjusting the unknown parameters of the multilayer. This approach enables us to determine orientations of the three principal axes in the substrate and the corresponding refractive indices. A special feature of our ellipsometers is that a glass hemisphere is placed in contact with the substrate, which eliminates the refraction of the incident light and enables a maximum propagation angle of 70 degrees (with respect to the normal) in the substrate. This increases the sensitivity of the measurement. Certain anomalies were observed, which we believe are associated with the presence of grooves on these substrates

Creep behavior of copper-chromium in-situ composite

Creep deformation and fracture behaviors were investigated on a deformation-processed Cu-Cr in-situ composite over a temperature range of 200 °C to 650 °C. It was found that the creep resistance increases significantly with the introduction of Cr fibers into Cu. The stress exponent and the activation energy for creep of the composite at high temperatures (≥400 °C) were observed to be 5.5 and 180 to 216 kJ/mol, respectively. The observation that the stress exponent and the activation energy for creep of the composite at high temperatures (≥400 °C) are close to those of pure Cu suggests that the creep deformation of the composite is dominated by the deformation of the Cu matrix. The high stress exponent at low temperatures (200 °C and 300 °C) is thought be associated with the as-swaged microstructure, which contains elongated dislocation cells and subgrains that are stable and act as strong athermal obstacles at low temperatures. The mechanism of damage was found to be similar for all the creep tests performed, but the distribution and extent of damage were found to be very sensitive to the test temperature

Entanglement and quantum phase transition in alternating XY spin chain with next-nearest neighbour interactions

By using the method of density-matrix renormalization-group to solve the different spin-spin correlation functions, the nearest-neighbouring entanglement(NNE) and next-nearest-neighbouring entanglement(NNNE) of one-dimensional alternating Heisenberg XY spin chain is investigated in the presence of alternating nearest neighbour interactions of exchange couplings, external magnetic fields and next-nearest neighbouring interactions. For dimerized ferromagnetic spin chain, NNNE appears only above the critical dimerized interaction, meanwhile, the dimerized interaction effects quantum phase transition point and improves NNNE to a large value. We also study the effect of ferromagnetic or antiferromagnetic next-nearest neighboring (NNN) interactions on the dynamics of NNE and NNNE. The ferromagnetic NNN interaction increases and shrinks NNE below and above critical frustrated interaction respectively, while the antiferromagnetic NNN interaction always decreases NNE. The antiferromagnetic NNN interaction results to a larger value of NNNE in comparison to the case when the NNN interaction is ferromagnetic.Comment: 13 pages, 4 figures,. accepted by Chinese Physics B 2008 11 (in press

The entanglement in one-dimensional random XY spin chain with Dzyaloshinskii-Moriya interaction

The impurities of exchange couplings, external magnetic fields and Dzyaloshinskii--Moriya (DM) interaction considered as Gaussian distribution, the entanglement in one-dimensional random $XY$ spin systems is investigated by the method of solving the different spin-spin correlation functions and the average magnetization per spin. The entanglement dynamics at central locations of ferromagnetic and antiferromagnetic chains have been studied by varying the three impurities and the strength of DM interaction. (i) For ferromagnetic spin chain, the weak DM interaction can improve the amount of entanglement to a large value, and the impurities have the opposite effect on the entanglement below and above critical DM interaction. (ii) For antiferromagnetic spin chain, DM interaction can enhance the entanglement to a steady value. Our results imply that DM interaction strength, the impurity and exchange couplings (or magnetic field) play competing roles in enhancing quantum entanglement.Comment: 12 pages, 3 figure

Study on the effects of the light CP-odd Higgs via the leptonic decays of pseudoscalar mesons

To explain the anomalously large decay rate of $\Sigma^+\to p+\mu^+\mu^-$, it was proposed that a new mechanism where a light CP-odd pseudoscalar boson of $m_{A_1^0}=214.3$ MeV makes a crucial contribution. Later, some authors have studied the transition $\pi^0\to e^+e^-$ and $\Upsilon\to \gamma A_1^0$ in terms of the same mechanism and their result indicates that with the suggested mass one cannot fit the data. This discrepancy might be caused by experimental error of $\Sigma^+\to p+\mu^+\mu^-$ because there were only a few events. Whether the mechanism is a reasonable one motivates us to investigate the transitions $\pi^0\to e^+e^-; \eta (\eta^\prime)\to \mu^+\mu^-; \eta_c\to \mu^+\mu^-; \eta_b\to\tau^+\tau^-$ within the same framework. It is noted that for $\pi^0\to e^+e^-$, the standard model (SM) prediction is smaller than the data, whereas the experimental central value of $\eta \to \mu^+\mu^-$ is also above the SM prediction. It means that there should be extra contributions from other mechanisms and the contribution of $A_1^0$ may be a possible one. Theoretically calculating the branching ratios of the concerned modes, we would check if we can obtain a universal mass for $A_1^0$ which reconcile the theoretical predictions and data for all the modes. Unfortunately, we find that it is impossible to have such a mass with the same coupling $|g_\ell|$. Therefore we conclude that the phenomenology does not favor such a light $A_1^0$, even though a small window is still open.Comment: 17 pages, 7 figures, 2 table

Electron correlation effects in electron-hole recombination in organic light-emitting diodes

We develop a general theory of electron--hole recombination in organic light emitting diodes that leads to formation of emissive singlet excitons and nonemissive triplet excitons. We briefly review other existing theories and show how our approach is substantively different from these theories. Using an exact time-dependent approach to the interchain/intermolecular charge-transfer within a long-range interacting model we find that, (i) the relative yield of the singlet exciton in polymers is considerably larger than the 25% predicted from statistical considerations, (ii) the singlet exciton yield increases with chain length in oligomers, and, (iii) in small molecules containing nitrogen heteroatoms, the relative yield of the singlet exciton is considerably smaller and may be even close to 25%. The above results are independent of whether or not the bond-charge repulsion, X_perp, is included in the interchain part of the Hamiltonian for the two-chain system. The larger (smaller) yield of the singlet (triplet) exciton in carbon-based long-chain polymers is a consequence of both its ionic (covalent) nature and smaller (larger) binding energy. In nitrogen containing monomers, wavefunctions are closer to the noninteracting limit, and this decreases (increases) the relative yield of the singlet (triplet) exciton. Our results are in qualitative agreement with electroluminescence experiments involving both molecular and polymeric light emitters. The time-dependent approach developed here for describing intermolecular charge-transfer processes is completely general and may be applied to many other such processes.Comment: 19 pages, 11 figure