Phase transition and phase coexistence in coupled rings with driven exclusion process

We study one-dimensional exclusion processes in two coupled closed rings consisting of a common diffusive channel and two parallel active (driven) channels. Our model displays bulk-driven phase transition and phase coexistence in the form of a localised domain wall (DW) in one of the active channels in a limit where the diffusive and driven dynamics compete. By controlling a splitting parameter which tunes the in-coming currents into the active channels, the system can be brought to a delocalisation transition, when delocalised DWs are formed in both the active channels. We characterise the DW fluctuations numerically.Comment: 8 pages,8 eps figure

Phase transitions and non-equilibrium relaxation in kinetic models of opinion formation

We review in details some recently proposed kinetic models of opinion dynamics. We discuss the several variants including a generalised model. We provide mean field estimates for the critical points, which are numerically supported with reasonable accuracy. Using non-equilibrium relaxation techniques, we also investigate the nature of phase transitions observed in these models. We study the nature of correlations as the critical points are approached, and comment on the universality of the phase transitions observed.Comment: 11 pages, 8 eps figures, 1 table. Contribution for proceedings of Statphys-Kolkata-VII 26-30 November, 201

Framing Pains, Pills, and Professors

Excerpt: We are accustomed to anabolic athletes, medicated musicians and souped-up students. Now it appears that we can add pill-popping professors to this list (Sahakian and Morein-Zamir 2007). “Cosmetic neurology” is the term I used to describe the practice of using neurologic interventions to improve movement, mood, and mentation in healthy individuals. The specific kinds of enhancements that might be possible and the ethical concerns (safety, distributive justice, coercion, and the erosion of character) they raise are detailed elsewhere (Chatterjee 2004, 2006). Despite ethical concerns, I have argued that the practice of cosmetic neurology is likely to become widespread (Chatterjee 2007). This point is predictive, not prescriptive. It means, though, that it is likely less useful to discuss whether this practice should occur than to consider what form this practice should take. Sorting this out will prove to be quite difficult itself, because translating principle into practice runs up against the problem of conflicting reference frames that can alter one’s view of the practice. These multiple reference frames determine what it means to be a good person or to construct a good society. I hope to illustrate the problem of conflicting reference frames by examining a special case, before returning to the issue that triggered this commentary— that of pill-popping professors...

Correspondence: A Medical View of Potential Adverse Effects

These letters respond to the Commentary \u27Towards responsible use of cognitive-enhancing drugs by the health\u27 by Henry Greely and colleagues. (Nature 456, 702-705; 2008

Neuroaesthetics: A Coming of Age Story

Neuroaesthetics is gaining momentum. At this early juncture, it is worth taking stock of where the field is and what lies ahead. Here, I review writings that fall under the rubric of neuroaesthetics. These writings include discussions of the parallel organizational principles of the brain and the intent and practices of artists, the description of informative anecdotes, and the emergence of experimental neuroaesthetics. I then suggest a few areas within neuroaesthetics that might be pursued profitably. Finally, I raise some challenges for the field. These challenges are not unique to neuroaesthetics. As neuroaesthetics comes of age, it might take advantage of the lessons learned from more mature domains of inquiry within cognitive neuroscience

Cosmetic Neurology and Cosmetic Surgery: Parallels, Predictions, and Challenges

As our knowledge of the functional and pharmacological architecture of the nervous system increases, we are getting better at treating cognitive and affective disorders. Along with the ability to modify cognitive and affective systems in disease, we are also learning how to modify these systems in health. “Cosmetic neurology,” the practice of intervening to improve cognition and affect in healthy individuals, raises several ethical concerns.1 However, its advent seems inevitable.2 In this paper I examine this claim of inevitability by reviewing the evolution of another medical practice, cosmetic surgery. Cosmetic surgery also enhances healthy people and, despite many critics, it is practiced widely. Can we expect the same of cosmetic neurology? The claim of inevitability poses a challenge for both physicians and bioethicists. How will physicians reconsider their professional role? Will bioethicists influence the shape of cosmetic neurology? But first, how did cosmetic surgery become common

Is it acceptable for people to take methylphenidate to enhance performance? No

A drug that can improve your exam results may sound tempting, and John Harris believes that we should embrace its possibilities. Anjan Chatterjee, however, argues that the dangers have been underplaye

Cosmetic Neurology and the problem of pain

Few people would argue against treating the traumatic psychological effects of war or violence. But what about taking a drug to lessen the pain of our common daily struggles, such as the end of a relationship or anxiety about one\u27s job? Is this a cosmetic enhancement of human life, even a danger to character, or is it an ethical choice? For guidance, the author looks to the history of treating physical pain and argues that, despite growing knowledge of the biological basis for psychological pain, many find it hard to find a consistent principled position when it comes down to specific instances of alleviating human sufferin