Beat-wave generation of plasmons in semiconductor plasmas

It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap semiconductors (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas.Comment: 11 pages, LaTex, no figures, no macro

Mapping and Scheduling Strategies for Heterogeneous Architectures

Extensive and computationally complex signal processing and control applications are commonly constructed from small computational blocks where the load decomposition and balance may not be easily achieved. This requires the development of mapping and scheduling strategies based on application to processor matching. In this context, several application algorithms are utilised and investigated in this work within the Development Framework (DF) approach. The DF approach supports the specification, design and implementation of real-time control systems. It also contains several mapping and scheduling tools to improve the performance of systems as well as tools for code generation. To improve the performance of an application, a new approach, namely the the priority-Based Genetic Algorithm, (PBGA) is developed and reported in this paper. The approach is applied to several applications using parallel and distributed heterogeneous architectures and its performance verified in comparison to several previously developed strategies

What are we measuring? Convergence of leadership with interpersonal and non-interpersonal personality.

Since leadership styles have been most commonly defined in terms of interpersonal influence, one would assume that they have their main projections on the interpersonal circumplex. In this study, the relations between leadership styles from the Multifactor Leadership Questionnaire and Leader Behaviour Description Questionnaire and both interpersonal and HEXACO personality scales are investigated. As expected, charismatic leadership and leader's consideration have strong projections on the interpersonal circumplex, with main projections on the warm-agreeable octant. Transactional leadership, passive leadership, and task-oriented leadership have considerably weaker or no projections on the circumplex. Leader's consideration is most strongly related to interpersonal personality while both transactional and passive leadership are most strongly related to non-interpersonal personality. It is concluded that especially charismatic leadership and leader's consideration are captured almost fully by the HEXACO personality inventory. Copyright © 2008 SAGE Publications

Ac Stark Effects and Harmonic Generation in Periodic Potentials

The ac Stark effect can shift initially nonresonant minibands in semiconductor superlattices into multiphoton resonances. This effect can result in strongly enhanced generation of a particular desired harmonic of the driving laser frequency, at isolated values of the amplitude.Comment: RevTeX, 10 pages (4 figures available on request), Preprint UCSBTH-93-2

Massive Electrodynamics and the Magnetic Monopoles

We investigate in detail the problem of constructing magnetic monopole solutions within the finite-range electrodynamics (i.e., electrodynamics with non-zero photon mass, which is the simplest extension of the standard theory; it is fully compatible with the experiment). We first analyze the classical electrodynamics with the additional terms describing the photon mass and the magnetic charge; then we look for a solution analogous to the Dirac monopole solution. Next, we plug the found solution into the Schr\"{o}dinger equation describing the interaction between the the magnetic charge and the electron. After that, we try to derive the Dirac quantization condition for our case. Since gauge invariance is lost in massive electrodynamics, we use the method of angular momentum algebra. Under rather general assumptions we prove the theorem that the construction of such an algebra is not possible and therefore the quantization condition cannot be derived. This points to the conclusion that the Dirac monopole and the finite photon mass cannot coexist within one and the same theory. Some physical consequences of this conclusion are considered. The case of t'Hooft-Polyakov monopole is touched upon briefly.Comment: 24 pages, revtex, 1 figure appended as a PostScript fil

Human Gene-Centered Transcription Factor Networks for Enhancers and Disease Variants

SummaryGene regulatory networks (GRNs) comprising interactions between transcription factors (TFs) and regulatory loci control development and physiology. Numerous disease-associated mutations have been identified, the vast majority residing in non-coding regions of the genome. As current GRN mapping methods test one TF at a time and require the use of cells harboring the mutation(s) of interest, they are not suitable to identify TFs that bind to wild-type and mutant loci. Here, we use gene-centered yeast one-hybrid (eY1H) assays to interrogate binding of 1,086 human TFs to 246 enhancers, as well as to 109 non-coding disease mutations. We detect both loss and gain of TF interactions with mutant loci that are concordant with target gene expression changes. This work establishes eY1H assays as a powerful addition to the toolkit of mapping human GRNs and for the high-throughput characterization of genomic variants that are rapidly being identified by genome-wide association studies

Peculiarities of the stochastic motion in antiferromagnetic nanoparticles

Antiferromagnetic (AFM) materials are widely used in spintronic devices as passive elements (for stabilization of ferromangetic layers) and as active elements (for information coding). In both cases switching between the different AFM states depends in a great extent from the environmental noise. In the present paper we derive the stochastic Langevin equations for an AFM vector and corresponding Fokker-Planck equation for distribution function in the phase space of generalised coordinate and momentum. Thermal noise is modeled by a random delta-correlated magnetic field that interacts with the dynamic magnetisation of AFM particle. We analyse in details a particular case of the collinear compensated AFM in the presence of spin-polarised current. The energy distribution function for normal modes in the vicinity of two equilibrium states (static and stationary) in sub- and super-critical regimes is found. It is shown that the noise-induced dynamics of AFM vector has pecuilarities compared to that of magnetisation vector in ferromagnets.Comment: Submitted to EPJ ST, presented at the 4-th Conference on Statistical Physics, Lviv, Ukraine, 201

Existential Communication and Leadership

The aim of this article is to introduce and explain a number of important existentialist philosophers and concepts that we believe can contribute to a critical approach to leadership theory. Emphasis is placed on understanding the nature of communication from an existentialist perspective and so Jaspers' conceptualization of existential communication is introduced along with important related concepts that may be regarded as important facets of leader communication including Being-in-the-world, the Other, intersubjectivity, dialogue and indirect communication. Particular attention is paid to Buber's ideas on communication as relationship and dialogue. Throughout, reference is made to contemporary, and what is often regarded as orthodox, thinking regarding the centrality of communication to leadership practice as a means by which to highlight the salience of an existentialist analysis