Structure and stability of helices in square-well homopolymers

Recently, it has been demonstrated [Magee et al., Phys. Rev. Lett. 96, 207802 (2006)] that isolated, square-well homopolymers can spontaneously break chiral symmetry and freeze into helical structures at sufficiently low temperatures. This behavior is interesting because the square-well homopolymer is itself achiral. In this work, we use event-driven molecular dynamics, combined with an optimized parallel tempering scheme, to study this polymer model over a wide range of parameters. We examine the conditions where the helix structure is stable and determine how the interaction parameters of the polymer govern the details of the helix structure. The width of the square well (proportional to lambda) is found to control the radius of the helix, which decreases with increasing well width until the polymer forms a coiled sphere for sufficiently large wells. The helices are found to be stable for only a window of molecular weights. If the polymer is too short, the helix will not form. If the polymer is too long, the helix is no longer the minimum energy structure, and other folded structures will form. The size of this window is governed by the chain stiffness, which in this model is a function of the ratio of the monomer size to the bond length. Outside this window, the polymer still freezes into a locked structure at low temperature, however, unless the chain is sufficiently stiff, this structure will not be unique and is similar to a glassy state.Comment: Submitted to Physical Review

Reintegrating Human and Nature: Modern Sentimental Ecology in Rachel Carson and Barbara Kingsolver

Rachel Carson and Barbara Kingsolver were both trained as scientists and may be expected to embrace the rationalist, mechanical view of nature as something separate from, and perhaps even inferior to, the world of humans. Yet these two women both promoted a more complex approach to modernism\u27s scientific paradigm in which nature is not merely a separate entity for dispassionate study but also an integral part of the human community. Both women display in their rhetorical choices a keen understanding of the language of community and interconnection, and their language and writing styles constantly promote the reintegration of humans and the natural world

Watching the Tour of California

Poem by Rick Magee

The Receptivity of Νοῦς in de Anima III.4

For Aristotle, the faculty of thought is legitimately characterized as being receptive of its objects. To construe Aristotle as holding that it is not renders a significant part of DA 3.4 to be of highly questionable internal coherence, since it makes it seem that he is claiming that something foreign might intrude into a power that has no organ and render that power inoperable. Moreover, failure to acknowledge the intellect\u27s receptivity renders what is clearly supposed to be an explanation (mind is unmixed because it 7 knows all things) otiose and virtually unrelated to the logic of his argument. Finally, the denial of the claim that νους is receptive forces onto Aristotle\u27s Greek a sense that is totally inconsistent with other uses of the same words. For these reasons, it seems best to hold that, at least through his first argument in DA 3.4, Aristotle did not begin his treatment of νους with a merely tentative comparison between the faculties of thought and perception according to the formal reception thesis, only to later abandon the claim that this thesis holds for νους. Rather, throughout this part of the chapter, Aristotle believes that νους is receptive since its receptivity is essential for the validity of his argument and the consistency of his thought.··;·

Nature, Domestic Labor, and Moral Community in Susan Fenimore Cooper\u27s Rural Hours and Elinor Wyllys

Cooper\u27s argument for a domestic ideal situated within a rural setting reinforces the importance of community connections through a shared sense of morality, as well as understanding of the natural world. Community alone—the human connections—never seems to be enough in Cooper\u27s formulation, but must always exist with an awareness of the world outside the narrow confines of one\u27s own domestic sphere. Concern for one\u27s fellow-beings necessitates a concern for the world in which these beings live, and Cooper understands that when any bonds are broken—such as the bonds that connect us to the natural world—other bonds are threatened. Thus, when we begin to care more for our environment, we awaken within ourselves the possibility of caring for the rest of our human community. At a time when environmentalists and other activists for social justice are urging us to think globally and act locally, it is perhaps a good moment to consider how Cooper, in her own subtle way, spoke of the power of the local and domestic to create a more just society

Is there really a way to prevent cancer? : Exploring cancer prevention information seeking among cancer patients and their caregivers

This thesis investigated cancer prevention information (CPI) seeking among cancer patients and their caregivers. Interviews that were conducted in 2011 were analyzed thematically to deconstruct perceptions and sources of CPI among 47 participants. The thematic narrative analysis of the predominantly Hispanic, low-income and low-education sample revealed differences in CPI seeking related to ways cultural practices and socioeconomic status impact information seeking. The digital divide, Spanish language and perceived high cost presented barriers to information yet created opportunities for patients and family members to emerge as health champions to share information interpersonally and intergenerationally. Understanding CPI processes of racial and ethnic minority, low-income, and Spanish-speaking patients and family members is necessary to better meet the needs of these populations

The Aridity of Grace: Community and Ecofeminism in Barbara Kingsolver\u27s Animal Dreams and Prodigal Summer

In both Animal Dreams and her later novel Prodigal Summer, Kingsolver constructs narratives of community inhabited by characters with a vivid awareness of the natural world and the threats to that world; furthermore, both novels feature strong female characters who long for a more harmonious life within nature. The novels develop and present forthright ecofeminist themes, with the women in the texts representing ideals of ecologically sensitive living who seek to educate their communities about threats to the environment and the defenses against those threats. Kingsolver\u27s ecofeminist vision, however, is frequently complicated and contradictory; just as the desert landscape presents its inhabitants with numerous challenges, Kingsolver\u27s narratives of community, by their very structure and implicit concerns, undermine and complicate her agenda

Ecology and Spirit: Reflections on the CIT Seminar

Professor Magee entered the CIT seminar in May of 2007 with some ideas about spirit and nature in American literature, and now, over a year later, he has, in the best traditions of philosophical enquiry, even more questions about how this complex relationship works. These new questions, however, have led to a significantly deeper and richer understanding of the texts I read, study, and teach, enlarging my intellectual horizons and sharpening my inquiries. His enriched scholarship has taken a number of forms, and in this report, hel briefly presents three specific and important examples