Meeting the Demand for Leadership Development

Due to its unique, flexible structure and low cost, virtually any student can participate in the Applied Tailored Leadership Adventure for Success (ATLAS) Leadership Certificate Program at the University of Arizona.     

A simple design method for the cosine-modulated filter banks using weighted constrained least square technique

This paper presents a simple and efficient design method for cosine-modulated filter banks with prescribed stopband attenuation, passband ripple, and channel overlap. The method casts the design problem as a linear minimization of filter coefficients such that their value at ω=π/2M is 0.707, which results in a simpler, more direct design procedure. The weighted constrained least squares technique is exploited for designing the prototype filter for cosine modulation (CM) filter banks. Several design examples are included to show the increased efficiency and flexibility of the proposed method over the exiting methods. An application of the proposed method is considered in the area of sub-band coding of the ECG and speech signals.     

Extending the rails: how research reshapes clinics

The purpose of clinical research is to create the scientific foundation for medical practice. In this way of thinking, the effect on medical practice occurs after the research has been completed. Social studies of science have debunked the standard model of scientific research, observing that changes in practice associated with research occur not just because of the results of research but also because of the practice of research. Drawing on fieldwork in HIV clinics in the US, South Africa,Thailand, and Uganda, we argue that clinical trials shape medical practice by altering the organizations in which both medical treatment and clinical trials take place. Three general processes are central to this transformation: the modification of material environments, the reorganization of bureaucratic relations, and the prioritization of research values. These processes unfold somewhat differently in the clinics of poorer countries than in those of wealthier ones.     

The electron mechanics of induction acceleration

The radial and axial motions of electrons in the betatron are described by means of a potential function of forces. Previously reported conditions of equilibrium, stability and damping of oscillations are derived for the region of parabolic variation of the potential. Extension of the analysis to, non-parabolic regions gives an account of the injection in conventional instruments in better agreement with experiment, particularly in regard to higher voltages of injection.Space charge limitations are discussed with the help of the Laplacian of the potential of forces.By means of an additional radial electric field electrons can be introduced as in the magnetron, without any asymmetry inherent in the conventional betatron circumferential injector. The analysis of the conditions of equilibrium and stability, greatly facilitated in this case by the notion of potential, shows that no substantial improvement in space charge limitations can be expected and that the required variations between the flux linking the electron orbits and the magnetic and electric fields at the orbits are difficult to realize on account of their complexity and narrow tolerances. The X-ray output of a small experimental double yoke instrument was measured by a phototube multiplier viewing an irradiated fluorescent screen and gave evidence of multiple group electron capture.