Approximating Cross-validatory Predictive P-values with Integrated IS for Disease Mapping Models

An important statistical task in disease mapping problems is to identify out- lier/divergent regions with unusually high or low residual risk of disease. Leave-one-out cross-validatory (LOOCV) model assessment is a gold standard for computing predictive p-value that can flag such outliers. However, actual LOOCV is time-consuming because one needs to re-simulate a Markov chain for each posterior distribution in which an observation is held out as a test case. This paper introduces a new method, called iIS, for approximating LOOCV with only Markov chain samples simulated from a posterior based on a full data set. iIS is based on importance sampling (IS). iIS integrates the p-value and the likelihood of the test observation with respect to the distribution of the latent variable without reference to the actual observation. The predictive p-values computed with iIS can be proved to be equivalent to the LOOCV predictive p-values, following the general theory for IS. We com- pare iIS and other three existing methods in the literature with a lip cancer dataset collected in Scotland. Our empirical results show that iIS provides predictive p-values that are al- most identical to the actual LOOCV predictive p-values and outperforms the existing three methods, including the recently proposed ghosting method by Marshall and Spiegelhalter (2007).Comment: 21 page

Hard X-ray and UV Observations of the 2005 January 15 Two-ribbon Flare

In this paper, we present comprehensive analysis of a two-ribbon flare observed in UV 1600{\AA} by Transition Region and Coronal Explorer and in HXRs by Reuven Ramaty High Energy Solar Spectroscopic Imager. HXR (25-100 keV) imaging observations show two kernels of size (FWHM) 15?? moving along the two UV ribbons. We find the following results. (1) UV brightening is substantially enhanced wherever and whenever the compact HXR kernel is passing, and during the HXR transit across a certain region, the UV count light curve in that region is temporally correlated with the HXR total flux light curve. After the passage of the HXR kernel, the UV light curve exhibits smooth monotonical decay. (2)We measure the apparent motion speed of the HXR sources and UV ribbon fronts, and decompose the motion into parallel and perpendicular motions with respect to the magnetic polarity inversion line (PIL). It is found that HXR kernels and UV fronts exhibit similar apparent motion patterns and speeds. The parallel motion dominates during the rise of the HXR emission, and the perpendicular motion starts and dominates at the HXR peak, the apparent motion speed being 10-40 km s-1. (3) We also find that UV emission is characterized by a rapid rise correlated with HXRs, followed by a long decay on timescales of 15-30 minutes. The above analysis provides evidence that UV brightening is primarily caused by beam heating, which also produces thick-target HXR emission. The thermal origin of UV emission cannot be excluded, but would produce weaker heating by one order of magnitude. The extended UV ribbons in this event are most likely a result of sequential reconnection along the PIL, which produces individual flux tubes (post-flare loops), subsequent non-thermal energy release and heating in these flux tubes, and then the very long cooling time of the transition region at the feet of these flux tubes.Comment: 8 figure

Vortex melting and decoupling transitions in YBa2_{2}Cu4_{4}O8_{8} single crystals

The vortex correlation along the c-axis in high quality single crystals of YBa$_{2}$Cu$_{4}$O$_{8}$ has been investigated as a function of temperature T in different magnetic fields, using the quasi-flux transformer configuration. A simultaneous sharp drop associated with the vortex lattice melting is observed in both the primary and secondary voltages(V$_{top}$ and V$_{bot}$). Just above the melting temperature, the vortices form three-dimensional line liquid with the correlation length along the c direction $L_{c}\leq$ t, the sample thickness. The temperature where a resistive peak in R$_{bot}$ develops corresponds to the decoupling temperature T$_{d}$ at which the vortices loose their correlation along the c-direction and they dissolve into the two dimensional pancake vortices. The H-T phase diagram for the YBa$_{2}$Cu$_{4}$O$_{8}$ single crystal is obtained.Comment: 1 Text file, 3 eps figure

Innovation Institution and Spatial Transfer of Energy Industry: The Case of Jiangsu Province, China

This study aims to explore the effect of innovation institution on spatial transfer of energy industry in Jiangsu, China. We focus on the disparity of innovation and energy industry, and analyze the spatial transfer difference in different types of energy industry, rather than view energy industry as a whole. The study demonstrates the spatial change of energy industry at regional level and maps the spatial pattern at city level. The study chooses intellectual property rights (IPRs) protection intensity, authorization patents and local research and development (R&D) investment as the proxy of innovation. Using official data and employing panel fixed-effect model at city-industry level, we conclude (a) innovation abilities significantly influence the spatial transfer of energy industry in Jiangsu. Especially, due to the different time, IPRs protection, patent counts, and R&D investment have different effects on different regions in Jiangsu; (b) 2010 is an important turning point for energy industry development in Jiangsu, and after 2010, the energy industry begins to shift to the middle and northern Jiangsu, whereas the spatial pattern of energy industry in coastal cities is basically unchanged; (c) there is a great difference between the regions in Jiangsu Province, and industrial upgrading has not been achieved in northern Jiangsu

Investigation into the design of ultra-wideband (UWB) and multi-band antennas

University of Technology, Sydney. Faculty of Engineering.The rapid development of high speed wireless communications as well as other applications such as microwave imaging place extraordinary demands on spectrums for which ultra-wideband (UWB) and multi-band, e.g.: dual-band, techniques are useful. These UWB and multi-band services require UWB and multi-band antenna designs. Motivated by these applications, we first carried out the investigations on the family of square plate monopole (SPM) antennas for UWB applications. The family of square plate monopole (SPM) UWB antennas yields quite attractive features, viz.: ease of fabrication and freedom of dielectric material selection. Next, we considered the use of coplanar waveguide (CPW) fed printed UWB antenna for compact, body-worn applications. We investigated the antenna performance using empirical optimisation. The work on CPW-fed printed antennas has led to the development of multi-band antennas also. For UWB antennas, we have first considered the modifications of well know square plate monopole (SPM) antennas. Our approach differs from other similar approaches on SPM antennas published in the literature. We have introduced symmetrical modifications to both bottom and top portions of the SPM antenna element. This has led to the development of these types of symmetrically modified SPM antennas, viz.: symmetrically beveled SPM (SB-SPM) antenna, symmetrical semi-circular base SPM (SSCB-SPM) antenna and symmetrically notched SPM (SN-SPM) antenna. All these antennas have been empirically optimised using Feko® and the theoretical and experimental results are provided, in the point of view of reflection coefficient, radiation characteristics, phase response of antenna transfer function and time domain response. For better suiting the compact and body-worn UWB applications, we have investigated the design of CPW-fed printed antenna. We have explored the antenna characteristics using empirical optimisation. The theoretical and experimental results for the completed CPW-fed printed antenna are provided, in the point of view of reflection coefficient, radiation characteristics, phase response of antenna transfer function, group delay and time domain response. Lately, for multi-band antennas, we have investigated the design of multi-band printed antennas, which are fed by CPW, to suit emerging design requirements. Two CPW-fed dual-band printed antennas for GSM and DCS/PCS as well as DCS/PCS and IEEE 802.11b applications are proposed, which have C-shape and T-shape structures respective1y. The theoretical and experimental results for these antennas are provided, in the point of view of reflection coefficient and radiation characteristics. Due to the use of substrate material for the designs of UWB CPW-fed printed antenna as well as C-shaped and T-shaped dual-band CPW-fed printed antennas, the effects of substrate material tolerances on UWB characteristics and dual-band characteristics are investigated. Furthermore, as these UWB and dual-band CPW-fed printed antennas are the promising candidates for wireless body-worn applications, which include wireless body area network (WBAN), the interactions between them and lossy material, such as human tissue, are investigated, which might help to decide the suitability of them for wireless body-worn applications

Thermodynamic Study of Inclusion Interactions between Gemini Surfactants and β-Cyclodextrin

The inclusion complexes of gemini surfactants, (CnN)2C12 (where n=12, 14), and β-cyclodextrin (β-CD) in aqueous solutions were investigated by an isothermal titration calorimetric method and 1H NMR spectroscopy at 293.15 K. The stability constants, stoichiometry, formation enthalpies, entropies and Gibbs energies for the complexes in aqueous solution have been derived from the calorimetric data. β-CDin aqueous  (C12N)2Cl2/(C14N)2Cl2 solutions forms 2:1 mole ratio host-guest complexes. The large values of the stability constants indicate that these complexes are stable in the aqueous solutions. The negative Gibbs energy  changes indicate that formation of the host-guest complexes is generally a spontaneous process. Both the formation enthalpy and formation entropy evidently decrease as the number of methylenes in each of the hydrophobic tails increase. The thermodynamic parameters are discussed in the light of the different  structures of the host and guest molecules. Chemical shift data of protons in the CD molecule, induced by the formation of the complexes have been determined by 1H NMR spectroscopy.KEYWORDS: Gemini surfactant, ;-cyclodextrin, isothermal titration calorimetry, 1H NMR

Work Function of Single-wall Silicon Carbide Nanotube

Using first-principles calculations, we study the work function of single wall silicon carbide nanotube (SiCNT). The work function is found to be highly dependent on the tube chirality and diameter. It increases with decreasing the tube diameter. The work function of zigzag SiCNT is always larger than that of armchair SiCNT. We reveal that the difference between the work function of zigzag and armchair SiCNT comes from their different intrinsic electronic structures, for which the singly degenerate energy band above the Fermi level of zigzag SiCNT is specifically responsible. Our finding offers potential usages of SiCNT in field-emission devices.Comment: 3 pages, 3 figure