10,000 publications from this institution
A model of two-dimensional arrays of Chua's circuits is numerically investigated. In a certain parameter region the spatiotemporal system has both synchronized oscillation and spiral wave attractors. Feedback pinnings are suggested to migrate the system from the spiral wave state to the coherent oscillation. The influences of the pinning density, forcing strength, and different pinning distributions on the driving effect are investigated. It is shown that some properly designed control schemes may reach very high control efficiency, i.e., killing a spiral wave consisting of a huge number of cells by injecting only very few cells. The wide applications of the approach are addressed.
Abstract : The current proceedings of the third conference, 'Fatigue 87', which was held at the University of Virginia, Charlottesville, covered a wide range of diverse views of the fundamental and applied aspects of fatigue. This includes questions of cycle deformation, crack initiation and propagations, small cracks, crack closure, variable amplitude effects, and environmentally-influenced behavior. The proceedings should provide a comprehensive state-of-the-art review of the field, suitable for students, researchers and practising engineers alike.
We show that the band gap bowing trends observed in III-V alloys containing dilute concentrations of Sb or Bi can be explained within the framework of the valence-band anticrossing model. Hybridization of the extended $p$-like states comprising the valence band of the host semiconductor with the close-lying localized $p$-like states of Sb or Bi leads to a nonlinear shift of the valence-band edge and a reduction of the band gap. The two alloys $\mathrm{Ga}{\mathrm{Sb}}_{x}{\mathrm{As}}_{1\ensuremath{-}x}$ and $\mathrm{Ga}{\mathrm{Bi}}_{x}{\mathrm{As}}_{1\ensuremath{-}x}$ are explored in detail, and the results are extrapolated to additional systems.
Campylobacter coli VC167 T2 has two flagellin genes, flaA and flaB, which share 91.9% sequence identity. The flaA gene is transcribed from a o-28 promoter, and the flaB gene from a o-54 promoter. Gene replacement mutagenesis techniques were used to generate flaA+ flaB and flaA flaB+ mutants. Both gene products are capable of assembling independently into functional filaments. A flagellar filament composed exclusively of the flaA gene product is indistinguishable in length from that of the wild type and shows a slight reduction in motility. The flagellar filament composed exclusively of the flaB gene product is severely truncated in length and greatly reduced in motility. Thus, while both flagellins are not necessary for motility, both products are required for a fully active flagellar filament. Although the wild-type flagellar filament is a heteropolymer of the flaA and flaB gene products, immunogold electron microscopy suggests that flaB epitopes are poorly surface exposed along the length of the wild-type filament.
Abstract This chapter seeks to broaden our view of criminalization by encompassing changing forms of urban dispossession and concurrent modalities of statecrafting, including penalization as a socially selective response to offending. It draws an analytic map of the research programme pursued across the author's three books Urban Outcasts (2008), Punishing the Poor (2009), and Deadly Symbiosis (2014). This trilogy disentangles the triangular nexus of class fragmentation, ethnic division, and statecrafting in the polarizing city at the century's turn to explain the political production, socio-spatial distribution, and punitive management of marginality through the wedding of disciplinary social policy and neutralizing criminal justice.
This article presents a case study of the effective synergy of health education inquiry, community collaboration, and policy advocacy. Using the Grandparent Caregiver Study as the example, the authors focus on key methodological decisions that enabled them to incorporate research, education, and advocacy activities into an ever-growing project on a modest budget. The study itself centered on two in-depth interviews with each of 71 African American grandmothers raising young grandchildren due to the crack cocaine epidemic in Oakland, California. The case study demonstrates ways in which health education research can increase the efficacy of individuals and disenfranchised groups to define problems, voice their concerns, and advocate for more just and healthy public policies. Through discussion of the authors' methods and activities, they suggest strategies through which research participants, service providers, and policymakers can work together to bring a new issue to the policy arena through a collaborative and empowering research process.
La validite de la relation Bibliotheque/Recherche est delimitee par certaines grandes lignes de caractere obligatoire: une philosophie de l'information, l'actualite comme base unique, une organisation prospective et des structures compatibles, une capacite a cooperer, une approche de specialiste de haut niveau. (INTD)
