5 7 5 line defects on As Si 100 A general stress relief mechanism for V IV surfaces

An entire family of nano scale trenches, ridges, and steps has been observed experimentally on AsH3 exposed Si 100 . Some of these line structures have been observed previously, but their structures have remained a mystery. Theoretical modeling shows that they are all based upon the same stress relieving 5 7 5 core structure. The strong similarities between line structures on As Si 100 , P Si 100 , As Ge 100 , and other V IV surfaces lead to a much broader conclusion 5 7 5 line structures are a general form of stress relief for group V terminated Si and Ge surface

The Calculated Effect of Various Hydrodynamic and Aerodynamic Factors on the Take-Off of a Large Flying Boat

Present designs for large flying boats are characterized by high wing loading, high aspect ratio, and low parasite drag. The high wing loading results in the universal use of flaps for reducing the takeoff and landing speeds. These factors have an effect on takeoff performance and influence to a certain extent the design of the hull. An investigation was made of the influence of various factors and design parameters on the takeoff performance of a hypothetical large flying boat by means of takeoff calculations. The parameters varied in the calculations were size of hull (load coefficient), wing setting, trim, deflection of flap, wing loading, aspect ratio, and parasite drag. The takeoff times and distances were calculated to the stalling speeds and the performance above these speeds was studied separately to determine piloting technique for optimum takeoff. The advantage of quick deflection of the flap at high water speeds is shown

Numerical studies of the two- and three-dimensional gauge glass at low temperature

We present results from Monte Carlo simulations of the two- and three-dimensional gauge glass at low temperature using the parallel tempering Monte Carlo method. Our results in two dimensions strongly support the transition being at T_c=0. A finite-size scaling analysis, which works well only for the larger sizes and lower temperatures, gives the stiffness exponent theta = -0.39 +/- 0.03. In three dimensions we find theta = 0.27 +/- 0.01, compatible with recent results from domain wall renormalization group studies.Comment: 7 pages, 10 figures, submitted to PR

Gravitational Waves in a Spatially Closed deSitter Spacetime

Perturbation of gravitational fields may be decomposed into scalar,vector and tensor components.In this paper we concern with the evolution of tensor mode perturbations in a spatially closed deSitter background of RW form. It may be thought as gravitional waves in a classical description. The chosen background has the advantage of to be maximally extended and symmetric. The spatially flat models commonly emerge from inflationary scenarios are not completely extended.We first derive the general weak field equations.Then the form of the field equations in two special cases, planar and spherical waves are obtained and their solutions are presented. We conclued with discussing the significance of the results and their implications.Comment: 16 pages,no figure

Work Readiness of New Graduate Physical Therapists for Private Practice in Australia: Academic Faculty, Employer, and Graduate Perspectives

OBJECTIVE: The purpose of this study is to explore academic faculty, employer, and recent graduate perspectives of the work readiness of Australian new graduate physical therapists for private practice and factors that influence new graduate preparation and transition to private practice. METHODS: This study used a mixed-methods design with 3 surveys and 12 focus groups. A total of 112 participants completed a survey, and 52 participated in focus groups. Descriptive statistics were used to summarize the quantitative data, and thematic analysis was used to analyze the qualitative data. Triangulation across participant groups and data sources was undertaken. RESULTS: Australian new graduate physical therapists were perceived to be "somewhat ready" for private practice and "ready" by their third year of employment. Participants proposed that new graduates bring enthusiasm, readiness to learn, and contemporary, research-informed knowledge. New graduates were also perceived to find autonomous clinical reasoning and timely caseload management difficult; to have limited business, marketing, and administration knowledge and skills; and to present with underdeveloped confidence, communication, and interpersonal skills. Factors perceived to influence graduate transition included private practice experience, such as clinical placements and employment; employer and client expectations of graduate capabilities; workplace support; university academic preparation and continuing education; and individual graduate attributes and skills. CONCLUSION: Australian new graduate physical therapists have strengths and limitations in relation to clinical, business, and employability knowledge and skills. New graduate work readiness and transition may be enhanced by additional private practice experience, employer and client expectation management, provision of workplace support, and tailored university and continuing education. IMPACT: The number of new graduate physical therapists employed in private practice in Australia is increasing; however, until this study, their work readiness for this setting was unknown. This exploration of new graduate performance in private practice and transition can help to increase understanding and enhancement of work-readiness

Evolution of the pairing pseudogap in the spectral function with interplane anisotropy

We study the pairing pseudogap in the spectral function as a function of interplane coupling. The analytical expressions for the self-energy in the critical regime are obtained for any degree of anisotropy. The frequency dependence of the self-energy is found to be qualitatively different in two and three dimensions, and the crossover from two to three dimensional behavior is discussed. In particular, by considering the anisotropy of the Fermi velocity and gap along the Fermi surface, we can qualitatively explain recent photoemission experiments on high temperature superconductors concerning the temperature dependent Fermi arcs seen in the pseudogap phase.Comment: 20 pages, revtex, 5 encapsulated postscript figures include

Dynamic Ordering and Transverse Depinning of a Driven Elastic String in a Disordered Media

We examine the dynamics of an elastic string interacting with quenched disorder driven perpendicular and parallel to the string. We show that the string is the most disordered at the depinning transition but with increasing drive partial ordering is regained. For low drives the noise power is high and we observe a 1/f^2 noise signature crossing over to a white noise character with low power at higher drives. For the parallel driven moving string there is a finite transverse critical depinning force with the depinning transition occuring by the formation of running kinks.Comment: 4 pages, 4 postscript figure

On the existence of a finite-temperature transition in the two-dimensional gauge glass

Results from Monte Carlo simulations of the two-dimensional gauge glass supporting a zero-temperature transition are presented. A finite-size scaling analysis of the correlation length shows that the system does not exhibit spin-glass order at finite temperatures. These results are compared to earlier claims of a finite-temperature transition.Comment: 4 pages, 2 figure

New directions in island biogeography

Aim: Much of our current understanding of ecological and evolutionary processes comes from island research. With the increasing availability of data on distributions and phylogenetic relationships and new analytical approaches to understanding the processes that shape species distributions and interactions, a re-evaluation of this ever-interesting topic is timely. Location: Islands globally. Methods: We start by arguing that the reasons why island research has achieved so much in the past also apply to the future. We then critically assess the current state of island biogeography, focusing on recent changes in emphasis, including research featured in this special issue of Global Ecology and Biogeography. Finally, we suggest promising themes for the future. We cover both ecological and evolutionary topics, although the greater emphasis on island ecology reflects our own backgrounds and interests. Results: Much ecological theory has been directly or indirectly influenced by research on island biotas. Currently, island biogeography is renascent, with research focusing on, among other things, patterns and processes underlying species interaction networks, species coexistence and the assembly of island communities through ecological and evolutionary time. Continuing island research should provide additional insight into biological invasions and other impacts of human activities, functional diversity and ecosystem functioning, extinction and diversification, species pools and more. Deeper understanding of the similarities and differences between island and mainland systems will aid transferability of island theory to continental regions. Main conclusions: As research in biogeography and related fields expands in new directions, islands continue to provide opportunities for developing insights, both as natural laboratories for ecology and evolution and because of the exceptions islands often present to the usual ‘rules’ of ecology. New data collection initiatives are needed on islands world-wide and should be directed towards filling gaps in our knowledge of within-island distributions of species, as well as the functional traits and phylogenetic relationships of island species

Computational aspects of the gravitational instability problem for a multicomponent cosmological medium

The paper presents results for deriving closed-form analytic solutions of the non-relativistic linear perturbation equations, which govern the evolution of inhomogeneities in a homogeneous spatially flat multicomponent cosmological model. Mathematical methods to derive computable forms of the perturbations are outlined.Comment: 20 pages in LaTeX, McGill University preprin