Reconstruction of Objects by Direct Demodulation

High resolution reconstruction of complicated objects from incomplete and noisy data can be achieved by solving modulation equations iteratively under physical constraints. This direct demodulation method is a powerful technique for dealing with inverse problem in general case. Spectral and image restorations and computerized tomography are only particular cases of general demodulation. It is possible to reconstruct an object in higher dimensional space from observations by a simple lower dimensional instrument through direct demodulation. Our simulations show that wide field and high resolution images of space hard X-rays and soft gamma rays can be obtained by a collimated non-position-sensitive detector without coded aperture masks.Comment: 11 pages, 6 figure

Less suppressed μ→eγ and τ→μγ loop amplitudes and extra dimension theories

AbstractWhen μeγ (or τμγ) loop involves a vector boson, the amplitude is suppressed by more than two powers of heavy particle masses. However we show that the scalar boson loop diagrams are much less damped. Particularly, the loop amplitude in which the intermediate fermion and scalar boson have comparable masses is as large as possible, as allowed by the decoupling theorem. Such a situation is realized in the “universal extra dimension theory”, and can yield a large enough rate for μeγ to be detectable in current experiments. Our investigation involves precise calculation of the scalar boson loop's dependence on the masses of the intermediate states

THE EFFECT OF LOAD CARRIAGE AND SCHOOLBAG DESIGN ON LATERAL TRUNK POSTURE DURING STAIRS DESCENT IN CHILDREN

The aim of this study was to investigate the way that the schoolbag weight combined with carrying method effects the trunk posture laterally during stairs descent. Thirteen male children performed stairs ascending and descending on a 33-step staircase at their natural cadence for three complete cycles with athletic bag and backpack, each with loads of 0%, 10%, 15% and 20% of their body weight. The trunk posture of one complete gait cycle during every descent was analyzed. Significant load effects on trunk posture were found when the load was increased from 0% to 15% when carrying athletic bag, and when the load was increased to 20% when carrying backpack. For loads of 10%, 15% and 20% the body weight, a backpack design significantly reduced the trunk posture alternation compared with athletic bag

CHANGES OF GAIT PATTERN ON SLIPPERY WALKING SURFACES IN SIMULATED CONSTRUCTION WORKSITE ENVIRONMENTS

This study aimed to investigate the gait pattern when walking on potential slippery surfaces. Twelve male subjects performed level walking at their natural cadence and without slips under sixteen simulated construction site walkway conditions with different floorings, contaminants and footwear. Gait pattern parameters were collected by video cameras and were analyzed by motion analysis system (APAS). Dynamic coefficients of friction (DCOF) of the walkway conditions were determined in a mechanical slip resistant test. Signifkant correlations were found with the DCOF for stance, swing and stride time. Significant increase in stance time, swing time and stride time, decrease in stride length and heel velocity at contact, and slower mean propagation speed were found when slippery potential increased. Further study is suggested to provide a more comprehensive explanation of human adaptation to slippery walking surface which helps proposing occupational safety in worksit

A PILOT STUDY ON COMPARISON OF CUSHIONING ABILITY OF CLOTH SPORT SHOE WITH OTHER ATHLETIC FOOTWEAR

Previous studies assessed the cushioning ability of different athletic footwear including running shoes and court shoes. In recent years, concern about the protective function of cloth sport shoe, a kind of low-price and popular athletic footwear in the youth generation for sport activities, has become popular in Hong Kong and the People's Republic of China. However, the cushioning ability of cloth sport shoe was still left uninvestigated. The purpose of this study was to give a preliminary assessment on the cushioning performance of cloth sport shoe compared with other types of sport shoes

Stability of Transonic Shock Solutions for One-Dimensional Euler-Poisson Equations

In this paper, both structural and dynamical stabilities of steady transonic shock solutions for one-dimensional Euler-Poission system are investigated. First, a steady transonic shock solution with supersonic backgroumd charge is shown to be structurally stable with respect to small perturbations of the background charge, provided that the electric field is positive at the shock location. Second, any steady transonic shock solution with the supersonic background charge is proved to be dynamically and exponentially stable with respect to small perturbation of the initial data, provided the electric field is not too negative at the shock location. The proof of the first stability result relies on a monotonicity argument for the shock position and the downstream density, and a stability analysis for subsonic and supersonic solutions. The dynamical stability of the steady transonic shock for the Euler-Poisson equations can be transformed to the global well-posedness of a free boundary problem for a quasilinear second order equation with nonlinear boundary conditions. The analysis for the associated linearized problem plays an essential role

Heavy particle electroweak loop effects in extra-dimensional models with bulk neutrinos

One way to detect the presence of new particles in theories beyond the standard model is through their contribution to electroweak loop effects. We comment on the importance of a consistent inclusion of their mixing angles to ensure that the physical requirement of heavy particle decoupling is fulfilled. We illustrate our points by a detailed discussion of the lepton flavor changing effect mu-e-gamma, investigated recently by Kitano, in the Randall-Sundrum model. Our remarks are equally applicable to models with large compactified dimensions where bulk neutrinos are introduced to account for the observed neutrino oscillations.Comment: 13 pages; new citations added in Ref [3] and [11

Secondary Electron Yield Measurements of Fermilab's Main Injector Vacuum Vessel

We discuss the progress made on a new installation in Fermilab's Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012) 20-25 May 2012, New Orleans, Louisian

Antiquark Polarization inside the Proton is Small

Quark contributions to the proton spin as deduced from polarized DIS of leptons off a nucleon target, and the octet baryon magnetic moments, can be used to deduce the antiquark polarizations $\Delta_{\overline{q}}$ inside the proton. In this way, the 1992 analysis by Karl is shown to imply $\Delta_{\overline{q}}\simeq 0.$ Such a spin structure fits nicely into the chiral quark interpretation of the proton spin and flavor puzzles.Comment: LaTex and RevTex, 7 pages, sub for pub in the Phys. Lett. B Corrected an equation number error, and revised the Author/Abstract field in the original E-preprint submission. Latex and Revtex. Sub to Phys. Lett.

Multiple sequence alignment based on set covers

We introduce a new heuristic for the multiple alignment of a set of sequences. The heuristic is based on a set cover of the residue alphabet of the sequences, and also on the determination of a significant set of blocks comprising subsequences of the sequences to be aligned. These blocks are obtained with the aid of a new data structure, called a suffix-set tree, which is constructed from the input sequences with the guidance of the residue-alphabet set cover and generalizes the well-known suffix tree of the sequence set. We provide performance results on selected BAliBASE amino-acid sequences and compare them with those yielded by some prominent approaches