30 resultados para Harvard College (1780- ).--Class of 1796.


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Dye-sensitized solar cells are an increasingly promising alternative to conventional silicon solar cells as a method of converting solar energy to electricity and thus providing an effectively inexhaustible energy source. However, the most efficient of these devices currently utilize liquid electrolytes, which suffer from the associated problems of leakage and evaporation. Hence, significant research is currently focused on the development of solid state alternatives. Here we report a new class of solid state electrolyte for these devices, organic ionic plastic crystal electrolytes, that allow relatively rapid diffusion of the redox couple through the matrix, which is critical to the cell performance. A range of different organic ionic plastic crystal materials, utilizing different cation and anion structures, have been investigated and the conductivities, diffusion rates and photovoltaic performance of the electrolytes are reported. The best material, utilizing the dicyanamide anion, achieves efficiencies of more than 5%.

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The Sexuality Education and Community Support (SECS) project aims to introduce a P-12 approach to sexuality education at Northern Bay P-12 College (NBC) through a collaborative partnership process between the schools within the College and local, regional, and state health and education agencies and has set out to change current sexual health education practice in the College and assist other schools in the region to do the same. The Project’s goal is a ‘sustainable, responsive, whole school, regionally consistent, best practice sexuality education’. During this first or establishment phase of the SECS project strategies have been implemented to begin the process of building capacity in sexuality education at NBC. These strategies are aimed at developing a sustainable approach during the next three and a half years.

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Pretty vacancy: The formation energy of Al vacancies in aluminum nitride is decreased by doping with nonmagnetic scandium ions. These vacancies are shown to be the cause of the room-temperature ferromagnetism in the resulting 1D hexagonal nanoprisms of AlN:Sc, a result that is confirmed by first-principles calculations. The doping approach provides a new route to dilute magnetic semiconductor materials.

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This paper concerns the adaptive fast finite-time multiple-surface sliding control (AFFTMSSC) problem for a class of high-order uncertain non-linear systems of which the upper bounds of the system uncertainties are unknown. By using the fast control Lyapunov function and the method of so-called adding a power integrator merging with adaptive technique, a recursive design procedure is provided, which guarantees the fast finite-time stability of the closed-loop system. Further, it is proved that the control input is bounded.

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Lithium is a unique and effective psychotropic agent with a long-standing history of clinical use yet it is increasingly overlooked in lieu of newer agents. The purpose of the present paper was to succinctly review the therapeutic profile of lithium particularly with respect to the treatment of mood disorders and consider its unique properties and clinical utility. A comprehensive literature review pertaining to lithium was undertaken using electronic database search engines to identify relevant clinical trials, meta-analyses and Cochrane reviews. In addition articles and book chapters known to the authors were carefully reviewed, and the authors appraised published guidelines. The evidence from these sources was rated using National Health and Medical Research Council evidence levels and synthesized according to phenotype and mood states. In addition, the authors have drawn upon published guidelines and their own clinical experience. Lithium has specificity for mood disorders with proven efficacy in the treatment of both unipolar depression and bipolar disorder. The recommendations are based predominantly on Level I evidence, but its clinical use has to be tempered against potential side-effects and the need for ongoing monitoring. In practice, lithium should be considered a first-line option in bipolar disorder, especially in prophylaxis and when onset of action is not an imperative. Lithium has been in use in modern medicine for 60 years and as such has been tried and tested across the full range of mood disorders. Arguably, lithium is the only true mood stabilizer and because of its unique properties is in a class of its own.

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Noting the ever-increasing encroachment of discourses and practices from the private sector on public education providers, this paper argues that such organizations exist within competing sets of differences that seek to define and fix the meaning of 'education' and 'business'. We report on fieldwork conducted in an adult education college in Sydney. In the Australian context these colleges are referred to as community colleges and their history is one based in a strong liberal tradition. Utilising Judith Butler's idea of 'drag' we consider the effects of changing modes of governance in the college with specific reference to the stories told to us about it. Our discussion suggests that the organisation was caught between identifying itself with a masculinised discourse of business and a discourse of community cast as its feminised other. In navigating between these, the college was seen to perform as a 'drag king' — an organisation performing the masculine but in so doing, undoing its gendered status. This leads us to suggest that the incorporation of business and market-based discourse into the management of community education is something that is actively resisted and undermined through such forms of gendered transgression. We conclude by proposing that this organization's capacity to perform drag is a contributing factor to its overall success, and particularly in an economic climate where many not-for-profit organisations are floundering

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Parallel manipulators provide several benefits compared to serial manipulators of similar size. These advantages typically include higher speed and acceleration, improved position accuracy and increased stiffness. However, parallel manipulators also suffer from several disadvantages. These drawbacks commonly include a small ratio of the positional workspace relative to the manipulator footprint and a limited rotational capability of the manipulated platform. A few parallel manipulators featuring a large ratio of the positional workspace relative to the footprint have been proposed. This paper investigates the feasibility of employing gearing to extend the range of the end-effector rotation of such mechanisms. The objective is to achieve parallel manipulators where both the positional and rotational workspace are comparable to that of serial manipulators.

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In this paper, the problem of global finite-time stabilisation by output feedback is considered for a class of stochastic nonlinear systems. First, based on homogeneous systems theory and the adding a power integrator technique, a homogeneous reduced order observer and control law are constructed in a recursive manner for the nominal system. Then, the homogeneous domination approach is used to deal with the nonlinearities in drift and diffusion terms; it is shown that the proposed output-feedback control law can guarantee that the closed-loop system is global finite-time stable in probability. Finally, simulation examples are carried out to demonstrate the effectiveness of the proposed control scheme.

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