Clustering of vacancy defects in high-purity semi-insulating SiC

Positron lifetime spectroscopy was used to study native vacancy defects in semi-insulating silicon carbide. The material is shown to contain (i) vacancy clusters consisting of 4--5 missing atoms and (ii) Si vacancy related negatively charged defects. The total open volume bound to the clusters anticorrelates with the electrical resistivity both in as-grown and annealed material. Our results suggest that Si vacancy related complexes compensate electrically the as-grown material, but migrate to increase the size of the clusters during annealing, leading to loss of resistivity.Comment: 8 pages, 5 figure

A neighboring extremal solution for an optimal switched impulsive control problem

This paper presents a neighboring extremal solution for a class of optimal switched impulsive control problems with perturbations in the initial state, terminal condition and system's parameters. The sequence of mode's switching is pre-specified, and the decision variables, i.e. the switching times and parameters of the system involved, have inequality constraints. It is assumed that the active status of these constraints is unchanged with the perturbations. We derive this solution by expanding the necessary conditions for optimality to first-order and then solving the resulting multiple-point boundary-value problem by the backward sweep technique. Numerical simulations are presented to illustrate this solution method

The Brain and the Behavioral Sciences

The increasing visibility and sense of intellectual opportunity associated with neuroscience in recent years have in turn stimulated a growing interest in its past. For the first time, a general reference book on the history of science has seen fit to include a review of the history of the brain and behavioral sciences as a thread to be reckoned with within the broader narrative tapestry. On the one hand, this looks like a welcome sign that a new historical subfield has “come of age.” On the other hand, when one settles down to the task of composing a “state of the art” narrative, one realizes just how much these are still early days. The bulk of available secondary literature still swims in a space between nostalgic narratives of great men and moments, big “march of ideas” overviews, and an unsystematic patchwork of more theorized forays by professional historians into specific themes (e.g., phrenology, brain localization, reflex theory). The challenge of imagining a comprehensive narrative is made all the more formidable by the fact that we are dealing here with a history that resists any easy or clean containment within disciplinary confines. The paper trail of ideas, experiments, clinical innovations, institutional networks, and high-stakes social debates not only moves across obvious sites of activity such as neurology, neurosurgery, and neurophysiology but also traverses fields as (only apparently) distinct as medicine, evolution, social theory, psychology, asylum management, genetics, philosophy, linguistics, anthropology, computer science, and theology.History of Scienc

I Going Away. I Going Home. : Austin Clarke\u27s Leaving this Island Place

Austin Clarke’s “Leaving This Island Place” is one of scores of Caribbean autobiographical works that focus on a bright, young, lower-class islander leaving his/her small island place and setting out on “Eldorado voyages.” The narrative of that journey away from home to Europe or Canada or the United States and the later efforts to return may be said to be the Caribbean story, as suggested in the subtitle of Wilfred Cartey’s study of Caribbean literature, Whispers from the Caribbean: I Going Away, I Going Home, which argues that while in Caribbean literature there is much movement away, there is also a body of literature in which “the notion of ‘away’ and images of movement out are replaced by images of return” (xvi). Traditionally, however, the first autobiographical works, such as George Lamming’s In the Castle of My Skin, V. S. Naipaul’s A House for Mr. Biswas, Merle Hodge’s Crick Crack, Monkey, Jamaica Kincaid’s Annie John, Michelle Cliff’s No Telephone to Heaven, Edwidge Danticat’s Breath, Eyes, Memory, and Elizabeth Nunez’s Beyond the Limbo Silence, have focused on the childhood in the Caribbean and the journey away—or at least the preparation for that journey. Such is the case with Clarke’s “Leaving This Island Place.

Managing diversity and European policy: Towards a typology for sport pedagogy

This article adds to the growing body of knowledge in sport pedagogy and focuses specifically upon the intersection of gender and disability. Its purpose is twofold, to create a typology for examining good practice in sport pedagogy that is reflective and inclusive and raises awareness of the diverse needs of all participants in physical activity 'regardless' of gender and ability for all children. We acknowledge that access to physical activity, education and sport are complex and multifaceted, however, the main purpose of this paper is to raise awareness of 'diversity' by focusing specifically upon the role of gender and ability. Through an examination of gender and disability policies in official European Union (EU) policy documents and commercial examples of policy-in-practice we propose a typology for diversity and diversity management. A close look at EU level is instructive because national policies of the member countries vary a lot with respect to diversity issues but should be in accordance in the main areas. Such a reading enables the building of a typology of recommendations for how such policy can be rendered in sport pedagogy practice. We suggest six significant, but related principles that include (1) mainstreaming; (2) teaching and coaching sensitive to difference; (3) empowerment; (4) inclusion; (5) adaptation; and (6) inner differentiation. This holistic typology seeks to 'mainstream' issues of gender and disability policy by providing a set of principles that can be applied to a range of teaching and coaching settings. © 2013 European College of Sport Science

Zeitminimale Berechnung von Rueckkopplungssteuerungen fuer optimale Lenkungsprobleme mit Anwendung in der Raumfahrt

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

A New General Guidance Method in Constrained Optimal Control - Part 2: Application to Space Shuttle Guidance

. The application and the performance of the neighboring optimal feedback scheme presented in Part 1 of this paper is demonstrated for the heating constrained cross-range maximization problem of a space-shuttle-orbiter-type vehicle. This problem contains five state and two control variables and a state variable inequality constraint of order zero. Key Words. Neighboring extremals, accessory minimum problem, feedback controls, neighboring optimum guidance, multiple shooting, guidance of space vehicles, space shuttle. 1 1. Introduction In Part 1 of this paper a numerical method for the real-time computation of neighboring optimum feedback controls is developed. In order to demonstrate the practical applicability and efficiency of this feedback scheme, we apply our method to a space flight optimization problem which describes the cross-range maximal re-entry of a space-shuttle-type vehicle under a reradiative heating constraint. We have chosen this problem, since it served for many yea..