Reconstruction of coded aperture images

Balanced correlation method and the Maximum Entropy Method (MEM) were implemented to reconstruct a laboratory X-ray source as imaged by a Uniformly Redundant Array (URA) system. Although the MEM method has advantages over the balanced correlation method, it is computationally time consuming because of the iterative nature of its solution. Massively Parallel Processing, with its parallel array structure is ideally suited for such computations. These preliminary results indicate that it is possible to use the MEM method in future coded-aperture experiments with the help of the MPP

Noise Tolerance of the BB84 Protocol with Random Privacy Amplification

We prove that BB84 protocol with random privacy amplification is secure with a higher key rate than Mayers' estimate with the same error rate. Consequently, the tolerable error rate of this protocol is increased from 7.5 % to 11 %. We also extend this method to the case of estimating error rates separately in each basis, which enables us to securely share a longer key.Comment: 26 pages, 1 figure, version 2 fills a logical gap in the proof. Version 3 includes an upper bound on the mutual information with finete code length by using the decoding error probability of the code. Version 4 adds a paragraph clarifying that no previous paper has proved that the BB84 with random privacy amplification can tolerate the 11% error rat

Pomeranchuk Instability in a non-Fermi Liquid from Holography

The Pomeranchuk instability, in which an isotropic Fermi surface distorts and becomes anisotropic due to strong interactions, is a possible mechanism for the growing number of experimental systems which display transport properties that differ along the $x$ and $y$ axes. We show here that the gauge-gravity duality can be used to describe such an instability in fermionic systems. Our holographic model consists of fermions in a background which describes the causal propagation of a massive neutral spin-two field in an asymptotically AdS spacetime. The Fermi surfaces in the boundary theory distort spontaneously and become anisotropic once the neutral massive spin-two field develops a normalizable mode in the bulk. Analysis of the fermionic correlators reveals that the low-lying fermionic excitations are non-Fermi liquid-like both before and after the Fermi surface shape distortion. Further, the spectral weight along the Fermi surface is angularly dependent and can be made to vanish along certain directions.Comment: Updated version to appear in PRD. New version has WKB analysis of spectral intensity in ordered phas

In situ XRF and gamma ray spectrometer for Mars sample return mission

A combined in situ X-ray fluorescence (XRF) and passive gamma ray spectrometer instrument is proposed for the chemical elemental analysis of various Martian surfaces and samples. The combined instrument can be carried on board a rover. The passive gamma ray or the neutron excited gamma ray system would be used to determine the elemental composition of the Martian surface while the rover is in motion. The XRF system would be used to perform analysis either on the Martian surface or on collected samples when the rover is stationary. The latter function is important both in cataloging the collected samples and in the selection of samples to be returned to earth. For both systems, data accumulation time would be on the order of 30 minutes. No sample preparation would be necessary

Detection of SiO emission from a massive dense cold core

We report the detection of the SiO (J = 2 - 1) transition from the massive cold dense core G333.125-0.562. The core remains undetected at wavelengths shorter than 70 micron and has compact 1.2 mm dust continuum. The SiO emission is localised to the core. The observations are part of a continuing multi-molecular line survey of the giant molecular cloud G333. Other detected molecules in the core include 13CO, C18O, CS, HCO+, HCN, HNC, CH3OH, N2H+, SO, HC3N, NH3, and some of their isotopes. In addition, from NH3 (1,1) and (2,2) inversion lines, we obtain a temperature of 13 K. From fitting to the spectral energy distribution we obtain a colour temperature of 18 K and a gas mass of 2 x 10^3 solar mass. We have also detected a 22 GHz water maser in the core, together with methanol maser emission, suggesting the core will host massive star formation. We hypothesise that the SiO emission arises from shocks associated with an outflow in the cold core.Comment: 6 pages, 4 figures, 1 table, to be published in MNRA

Music education reform in Taiwan: beginning music teachers' perceptions of their teacher preparation at National Taiwan Normal University

Thesis (D.M.A.)--Boston UniversityThe purpose of this study was to investigate beginning music teachers' perceptions oftheir music teacher preparation at National Taiwan Normal University (NTNU) regarding the Arts and Humanities field of the Grade 1-9 Curriculum. Research questions focused on discovering the most and least effective components of undergraduate training at NTNU, identifying the missing components that might have helped beginning music teachers begin their profession more effectively, and having graduates involved in program improvement by presenting their recommendations. A descriptive analysis was conducted on the data received from 129 graduates from the music department ofNational Taiwan Normal University (NTNU). Of the 129 respondents, 69 took teacher education courses and were prospective music teachers. However, due to an overabundance of certified teachers in Taiwan, only 27 of the 69 graduates were able to obtain teaching positions. Beginning music teachers' experiences with student teaching, course content (Research in Music Teaching Materials and Methods), and applied music (voice), while in the teacher preparation program, helped prepare them to enter and be successful in the secondary music classroom. On the contrary, theoretical courses and advanced musicianship training were reported disconnected from the actual working experiences of beginning music teachers. The components which beginning music teachers expressed they wished had been taught in the undergraduate training program included teaching methods, classroom management, communication skills, knowledge of subject content (i.e., performing arts), music technology, and the theory of curriculum integration design and practice. In the hope of improving the shortcomings and linking the disconnections between training and work, beginning music teachers recommended the music teacher preparation program at NTNU increase the amount of coursework related to classroom realities, extend student teaching, provide more opportunities for classroom observations as well as professional development, and offer teacher education courses earlier in the program