13,140 research outputs found

    Solvent coarse-graining and the string method applied to the hydrophobic collapse of a hydrated chain

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    Using computer simulations of over 100,000 atoms, the mechanism for the hydrophobic collapse of an idealized hydrated chain is obtained. This is done by coarse-graining the atomistic water molecule positions over 129,000 collective variables that represent the water density field and then using the string method in these variables to compute the minimum free energy pathway (MFEP) for the collapsing chain. The dynamical relevance of the MFEP (i.e. its coincidence with the mechanism of collapse) is validated a posteriori using conventional molecular dynamics trajectories. Analysis of the MFEP provides atomistic confirmation for the mechanism of hydrophobic collapse proposed by ten Wolde and Chandler. In particular, it is shown that lengthscale-dependent hydrophobic dewetting is the rate-limiting step in the hydrophobic collapse of the considered chain.Comment: 11 pages, 7 figures, including supporting informatio

    Effects of hydrogen on ELI titanium alloy Ti-5Al-2.5Sn

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    Tensile tests on titanium alloy, following abrasion under hydrogen and temperature cycling, reveal lowered tensile strength, increased ductility, and no embrittlement. Fretting the metal on itself in flowing hydrogen or abrading with an iron file in flowing hydrogen produces titanium hydride

    Neoliberalism and the Mapuche

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    The Mapuche Indians are the largest indigenous group in Chile and they account for nearly ten percent of the country’s total population. The Mapuche have struggled with land usurpations since the end of the nineteenth century. The most difficult of these struggles came from neoliberal economic policies of the Military dictatorship of Augusto Pinochet (1973-1990). Laws such as Decree Law 2568 that dissolved Mapuche communal land and divided it up into individually held land titles. With the return of democracy in 1990 the Mapuche had hope that Pinochet era policies would disappear. This hope was realized in 1993 when Indigenous Law 19253. Harmful aspects of Decree 2568 were repealed by the Indigenous Law, but the ideas and polices have continued to be use by the Chilean government. Under the pretext of promoting civilization, the neoliberal legal framework allowed for usurpation of ancestral territory resulting in the destruction of entire communities, and repression of any protest to industrial projects

    Reframing the Ethics of Care: Implications for Moral Epistemology in Bioethics

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    The paper investigates the challenges of knowledge in the physician-patient relationship, both the patient\u27s lack of expert medical knowledge and understanding of his or her medical condition as well as the physician\u27s ignorance of the patient\u27s values and belief systems. Employing an ethic of care, the aim is to bring attention to this dual epistemological difficulty in the patient-provider relationship. The ethics of care provides a lens for understanding, establishing empathy for the patient,and seeking methods in which the patient may become empowered. Channeling the ideas of Dr. Edmund Pellegrino, the paper explicates the argument advanced by Virginia Ashby Sharpe in her article Justice and Care: The Implications of The Kohlberg-Gilligan Debate by assessing the conflict between the care and justice orientations in medical ethics. Sharpe concludes that the care orientation is congruent with Dr. Pellegrino\u27s medical morality within the physician-patient relationship. I argue that health care providers need a blend of both the care and justice orientations in order to appropriately apply universal principles to particular medical relationships. I conclude that a blend of both orientations would provide a richer foundational ethic for health care providers as they attend to the suffering of individual patients

    The End of School Busing? School Desegregation and the Finding of Unitary Status

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