Efficient current-induced domain-wall displacement SrRuO3

We demonstrate current-induced displacement of ferromagnetic domain walls in sub-micrometer fabricated patterns of SrRuO3 films. The displacement, monitored by measuring the extraordinary Hall effect, is induced at zero applied magnetic field and its direction is reversed when the current is reversed. We find that current density in the range of 10^9 - 10^10 A/m^2 is sufficient for domain-wall displacement when the depinning field varies between 50 to 500 Oe. These results indicate relatively high efficiency of the current in displacing domain walls which we believe is related to the narrow width ~3 nm of domain walls in this compound

Another Thing Needful : Exploring Emotions in Law. Book Review Of: The Passions of Law. Edited by Susan A. Bandes

Book review: The passions of law. Edited by Susan A. Bandes. New York University Press. 1999. Pp. 367. Reviewed by: Neal Feigenso

The Role of Wnt Signaling in Oligodendrocyte Development

Abstract The Role of Wnt Signaling in Oligodendrocyte Development Keith Feigenson Judith Grinspan, Ph.D. The developmental regulation of the central nervous system is established through a complex network of signaling factors that control the timing of cell generation, specification, migration, and differentiation. Oligodendrocytes, the myelinating cells of the central nervous system, originate during embryonic stages in ventricular zones and are responsive to many of these inductive and inhibitory signals as they migrate, mature, and interact with axons. The specific timing and regulation of these actions are critical to axonal conductance. Many signals that promote oligodendrocyte specification and differentiation are active ventrally, and more recent studies have examined the less well known actions of several inhibitory dorsal signaling factors, among these the Bone morphogenic proteins (BMPs) and Wnt signaling factors. I investigated the role of the canonical Wnt signaling pathway in oligodendrocyte development, both in vivo and in vitro. In primary oligodendrocyte precursor culture systems, canonical Wnt activity inhibits the differentiation of precursors, maintaining them in the precursor stage without causing a change in proliferation, cell death, or cell fate determination. Following these studies, I generated mice with a gain of function Wnt signaling mutation targeted to cells of oligodendroglial lineage. These mice had significant delays in myelin forming cell development early in development, but seemed to recover upon reaching adulthood. Together, these findings indicate that Wnt activity is sufficient to delay oligodendrocyte maturation in vivo and in vivo. I also investigated the interaction between the Wnt and BMP signaling pathways during oligodendrocyte development. Using pharmacological and genetic paradigms, I found that when the canonical BMP signaling pathway is abrogated, neither BMP nor Wnt manipulation has any effect on oligodendrocyte differentiation in culture. In contrast, blocking the canonical Wnt signaling pathway does not limit the activities of BMP, suggesting that the effect of Wnt signaling on oligodendrocyte development is dependent on BMP signaling, but not vice versa. These two facets of my thesis offer insight into the signaling mechanisms regulating the timing of oligodendrocyte development, and could have implications for the treatment of demyelinating disorders and central nervous system injury

Another Thing Needful : Exploring Emotions in Law. Book Review Of: The Passions of Law. Edited by Susan A. Bandes

Book review: The passions of law. Edited by Susan A. Bandes. New York University Press. 1999. Pp. 367. Reviewed by: Neal Feigenso

Can Tort Juries Punish Competently?

Punitive damages have prompted much academic and political debate during the last twenty years. In their recent book Punitive Damages, Cass Sunstein, Reid Hastie, John Payne, David Schkade, and W. Kip Viscusi present some twenty experimental studies that, they argue, show that juries award punitive damages too often, that the amounts they award are erratic and unpredictable, and that their decision-making processes are prone to various cognitive biases and other irrationalities, displaying a particular disregard of the principle of optimal deterrence. While the book offers much reliable and valuable data on how juries think about punitive damages, the authors frequently describe their results tendentiously, downplaying or omitting considerations that would support alternative interpretations of the data. Most importantly, by emphasizing deterrence to the exclusion of the retributive function that punitives are widely thought to serve, the authors present an unduly pejorative picture of juries\u27 punitive damages decision making and overstate the need for reforming the process