Quantisation of Conformal Fields in Three-dimensional Anti-de Sitter Black Hole Spacetime

Utilizing the conformal-flatness nature of 3-dim. Anti-de Sitter (AdS_3) black hole solution of Banados, Teitelboim and Zanelli, the quantisation of conformally-coupled scalar and spinor fields in this background spacetime is explicitly carried out. In particular, mode expansion forms and propagators of the fields are obtained in closed forms. The vacuum in this conformally-coupled field theories in AdS_3 black hole spacetime, which is conformally-flat, is the conformal vacuum which is unique and has global meaning. This point particularly suggests that now the particle production by AdS_3 black hole spacetime should be absent. General argument establishing the absence of real particle creation by AdS_3 black hole spacetime for this case of conformal triviality is provided. Then next, using the explicit mode expansion forms for conformally-coupled scalar and spinor fields, the bosonic and fermionic superradiances are examined and found to be absent confirming the expectation.Comment: 51 pages, Revtex, version to appear in Int. J. Mod. Phys.

Improved determination of color-singlet nonrelativistic QCD matrix elements for S-wave charmonium

We present a new computation of S-wave color-singlet nonrelativistic QCD matrix elements for the J/psi and the eta_c. We compute the matrix elements of leading order in the heavy-quark velocity v and the matrix elements of relative order v^2. Our computation is based on the electromagnetic decay rates of the J/psi and the eta_c and on a potential model that employs the Cornell potential. We include relativistic corrections to the electromagnetic decay rates, resumming a class of corrections to all orders in v, and find that they significantly increase the values of the matrix elements of leading order in v. This increase could have important implications for theoretical predictions for a number of quarkonium decay and production processes. The values that we find for the matrix elements of relative order v^2 are somewhat smaller than the values that one obtains from estimates that are based on the velocity-scaling rules of nonrelativistic QCD.Comment: 31 pages, minor corrections, version published in Phys. Rev.

Oligopolistic manufacturing and economic reform in four archetype western pacific economies: model construction and analysis

To examine the effects of policy intervention in the presence of imperfect competition in manufacturing, general equilibrium models are constructed of four Western Pacific economies, chosen according to their level of development and the comparative sizes of their manufacturing sectors. The countries chosen are Australia, an industrialised importer of manufactures, Japan, an industrialised exporter, the Philippines, a developing importer, and the Republic of Korea, a developing exporter. In each case the manufacturing sector is characterised as comprising nine separate industries, each with identical oligopolistic firms producing homogeneous goods which are differentiated from competing imports. The economies are subjected to exogenous shocks, which include trade reforms, increased surveillance of pricing behaviour, technological change and shifts in the terms of trade. Differences in the simulated economic responses in each case are examined and discussed. This paper also offers a complete specification of the model used and a detailed description of the construction of databases for the four countries

Defect cluster recognition system for fabricated semiconductor wafers

The International Technology Roadmap for Semiconductors (ITRS) identifies production test data as an essential element in improving design and technology in the manufacturing process feedback loop. One of the observations made from the high-volume production test data is that dies that fail due to a systematic failure have a tendency to form certain unique patterns that manifest as defect clusters at the wafer level. Identifying and categorising such clusters is a crucial step towards manufacturing yield improvement and implementation of real-time statistical process control. Addressing the semiconductor industry's needs, this research proposes an automatic defect cluster recognition system for semiconductor wafers that achieves up to 95% accuracy (depending on the product type)

Spin relaxation in mesoscopic superconducting Al wires

We studied the diffusion and the relaxation of the polarized quasiparticle spins in superconductors. To that end, quasiparticles of polarized spins were injected through an interface of a mesoscopic superconducting Al wire in proximity contact with an overlaid ferromagnetic Co wire in the single-domain state. The superconductivity was observed to be suppressed near the spin-injecting interface, as evidenced by the occurrence of a finite voltage for a bias current below the onset of the superconducting transition. The spin diffusion length, estimated from finite voltages over a certain length of Al wire near the interface, was almost temperature independent in the temperature range sufficiently below the superconducting transition but grew as the transition temperature was approached. This temperature dependence suggests that the relaxation of the spin polarization in the superconducting state is governed by the condensation of quasiparticles to the paired state. The spin relaxation in the superconducting state turned out to be more effective than in the normal state.Comment: 9 pages, 8 figure

The Determinants of Inappropriate Use of Antibiotics among Working Age Population in Western Cambodia

BACKGROUND: Antibiotics are among the most commonly sold drugs in the developing countries. The inappropriate use of antibiotics could result not only resistant bacterial strains but also adverse reactions and economic burden. This study aimed to describe the antibiotics use characteristics and identify factors associated with inappropriate use of antibiotics among working age population in western Cambodia. SUBJECT AND METHODS: This was a cross sectional study. A sample of 344 subjects aged 18-59 years old was selected at random from 10 communes of three provinces in Western Cambodia. A structured questionnaire was developed to collect the data. The dependent variable was inappropriate use of antibiotics. The independent variable included average monthly family income, habitual use of medicine. A logistic regression was used to analyze the data. RESULTS: 23.84% of the sample used antibiotic during the past 3 months, of which 14.83% were inappropriate use. The multivariate analy- sis indicated factor associated with inappropriate use of antibiotics were: low family income (adj. OR = 3.39; 95%CI: 1.18 to 9.74; p=0.024) and habitual use of oral antibiotics when having a cold (adj. OR=6.44; 95% CI: 1.55 to 26.91; p=0.010). The protective factor was habit of using oral anti- biotics when having sorethroat (adj. OR=0.24; 95%CI: 0.08 to 0.78; p=0.018). CONCLUSION: Almost a quarter of the samples used antibiotics. Low income and inappropriate antibiotic administration in respiratory tract infection increase the risk of antibiotic misuse. Keywords: inappropriate use, antibiotics, income, habit, working age population

Solvent Effects on Optical Properties of Molecules: A Combined Time-Dependent Density Functional Theory/Effective Fragment Potential Approach

A quantum mechanics/molecular mechanics (QM/MM) type of scheme is employed to calculate the solvent-induced shifts of molecular electronic excitations. The effective fragment potential (EFP) method was used for the classical potential. Since EFP has a density dependent functional form, in contrast with most other MM potentials, time-dependent density functional theory (TDDFT) has been modified to combine TDDFT with EFP. This new method is then used to perform a hybrid QM/MM molecular dynamics simulation to generate a simulated spectrum of the n→π∗ vertical excitation energy of acetone in vacuum and with 100 water molecules. The calculated watersolvent effect on the vertical excitation energy exhibits a blueshift of the n→π∗ vertical excitation energy in acetone (Δω1=0.211 eV), which is in good agreement with the experimental blueshift

The upper ocean response to the monsoon in the Arabian Sea

Thesis (Ph.D.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and the Woods Hole Oceanographic Institution), 2000.Includes bibliographical references (p. 217-222).Estimation of the upper ocean heat budget from one year of observations at a moored array in the north central Arabian Sea shows a rough balance between the horizontal advection and time change in heat when the one-dimensional balance between the surface heat flux and oceanic heat content breaks down. The two major episodes of horizontal advection, during the early northeast (NE) and late southwest (SW) monsoon seasons, are both associated with the propagation of mesoscale eddies. During the NE monsoon, the heat fluxes within the mixed layer are not significantly different from zero, and the large heat flux comes from advected changes in the thermocline depth. During the SW monsoon a coastal filament exports recently upwelled water from the Omani coast to the site of the array, 600 km offshore. Altimetry shows mildly elevated levels of surface eddy kinetic energy along the Arabian coast during the SW monsoon, suggesting that such offshore transport may be an important component of the Arabian Sea heat budget. The sea surface temperature (SST) and mixed layer depth are observed to respond to high frequency (HF, diurnal to atmospheric synoptic time scales) variability in the surface heat flux and wind stress. The rectified effect of this HF forcing is investigated in a three-dimensional reduced gravity thermodynamic model of the Arabian Sea and Indian Ocean. Both the HF heat and wind forcing act locally to increase vertical mixing in the model, reducing the SST. Interactions between the local response to the surface forcing, Ekman divergences, and remotely propagated signals in the model can reverse this, generating greater SSTs under HF forcing, particularly at low latitudes. The annual mean SST, however, is lowered under HF forcing, changing the balance between the net surface heat flux (which is dependent on the SST) and the meridional heat flux in the model. A suite of experiments with one-dimensional upper ocean models with different representations of vertical mixing processes suggests that the rectified effect of the diurnal heating cycle is dependent on the model, and overstated in the formulation used in the three-dimensional model.by Albert Sok Fischer.Ph.D

Arabian Sea mixed layer deepening during the monsoon : observations and dynamics

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.Includes bibliographical references (p. 127-130).by Albert S. Fischer.M.S