Analysis of a diffusive effective mass model for nanowires

We propose in this paper to derive and analyze a self-consistent model describing the diffusive transport in a nanowire. From a physical point of view, it describes the electron transport in an ultra-scaled confined structure, taking in account the interactions of charged particles with phonons. The transport direction is assumed to be large compared to the wire section and is described by a drift-diffusion equation including effective quantities computed from a Bloch problem in the crystal lattice. The electrostatic potential solves a Poisson equation where the particle density couples on each energy band a two dimensional confinement density with the monodimensional transport density given by the Boltzmann statistics. On the one hand, we study the derivation of this Nanowire Drift-Diffusion Poisson model from a kinetic level description. On the other hand, we present an existence result for this model in a bounded domain

Searches for Long-lived Particles at the Tevatron Collider

Several searches for long-lived particles have been performed using data from p-pbar collisions from Run II at the Tevatron. In most cases, new analysis techniques have been developed to carry out each search and/or estimate the backgrounds. These searches expand the discovery potential of the CDF and D0 experiments to new physics that may have been missed by traditional search techniques. This review discusses searches for (1) neutral, long-lived particles decaying to muons, (2) massive, neutral, long-lived particles decaying to a photon and missing energy, (3) stopped gluinos, and (4) charged massive stable particles. It summarizes some of the theoretical and experimental motivations for such searches.Comment: submitted to Mod. Phys. Lett.

Concept for a large master/slave-controlled robotic hand

A strategy is presented for the design and construction of a large master/slave-controlled, five-finger robotic hand. Each of the five fingers will possess four independent axes each driven by a brushless DC servomotor and, thus, four degrees-of-freedom. It is proposed that commercially available components be utilized as much as possible to fabricate a working laboratory model of the device with an anticipated overall length of two-to-four feet (0.6 to 1.2 m). The fingers are to be designed so that proximity, tactile, or force/torque sensors can be imbedded in their structure. In order to provide for the simultaneous control of the twenty independent hand joints, a multilevel master/slave control strategy is proposed in which the operator wears a specially instrumented glove which produces control signals corresponding to the finger configurations and which is capable of conveying sensor feedback signals to the operator. Two dexterous hand master devices are currently commercially available for this application with both undergoing continuing development. A third approach to be investigated for the master control mode is the use of real-time image processing of a specially patterned master glove to provide the respective control signals for positioning the multiple finger joints

Solving Modal Equations of Motion with Initial Conditions Using MSC/NASTRAN DMAP

By utilizing MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systems. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated

Response dependence of reversal‐related ERP components in perception of ambiguous figures

Perceptual multi‐stability is characterized by alternating interpretations of an unchanging stimulus input. The reversal negativity (RN) and reversal positivity (RP) ERP components show differences in electrophysiological responses between trials on which participants experience a perceptual reversal of a multi‐stable stimulus versus trials without a reversal (i.e., stable). However, it is unclear to what extent these two ERP components reflect reversal‐related perceptual processing rather than task and response processes. To address this, we varied task and response requirements while measuring the RN and RP. In the standard reversal task, participants indicated whether they saw a perceptual reversal on each trial. In contrast, in the identity task participants reported perceived identity of the stimulus (e.g., face or vase) without any reference to reversals. In some blocks, reversal trials required a response whereas in other blocks stable trials required a response. We found that the RN appeared independently of task and response style. However, the early latency RP component was only present when participants responded manually. For non‐response trials, a component was found during the same latency as the RP but with inverted polarity. Our results suggest that the early RP component is dependent on response‐related processes rather than being a pure neural signature of perceptual processes related to endogenous perceptual reversals

On Robustness Analysis in the Control of Nonlinear Systems

This paper deals with the class of nonlinear systems described by the equation M(q(t))q(t) = f(t) - N(q(t),q¿(t)) with f(t) a control input. We employ a simple method of control design which has two stages. First, a global linearization is performed to yield a decoupled controllable linear system. Then a controller is designed for this linear system. We provide a rigorous analysis of the effects of uncertain dynamics, which we study using robustness results in the time domain based on a Lyapunov equation and the total stability theorem. Using this approach we are able to give meaningful robustness bounds which justify assumptions that are currently made in the literature in an ad hoc fashion

Cordylobia Anthropophaga: Furuncular Myiasis in a Family of 3

Cutaneous myiasis due to infestation by the larva of Cordylobia anthropophaga is an underreported occurrence. Awareness is important to avoid misrecognition or delay in diagnosis. We describe a family of three with cutaneous myiasis caused by the African Tumbu fly (Cordylobia anthropophaga) presenting as multiple abscesses, demonstrating the need for a detailed travel history in such a presentation. The nature of the lesions, the life cycle and treatment modalities are discussed. Cutaneous myiasis requires an awareness of its clinical features specifically in patients presenting with furuncular skin lesions who live within endemic areas or persons returning from such areas. Diagnosis is mainly clinical and lesions heal well after the extraction of the larvae. Good personal hygiene including ironing of clothes is crucial in controlling C. anthropophaga infestation.Key Words: Myiasis, Furuncular, Cordylobia anthropophag

An unusual presentation of acute lymphoblastic leukaemia with peri-cardial effusion causing cardiac tamponade

Peri-cardial effusion is most commonly associated with tuberculous infection in the developing world. Peri-cardial effusion causes symptoms when it is large or when it has accumulated rapidly. Non-tuberculous causes of peri-cardial effusion include bacterial infections, uraemia, viral infections, rheumatic fever, connective tissue disorders, post – peri-cardiotomy syndromes and malignancy. We present a case of acute lymphoblastic leukaemia first presenting as a large peri-cardial effusion causing tamponade