Random access-random release relay switching matrix

XY relay switching matrix provides complete random access and random release of 400 points. A mercury-wetted bistable relay with independent set and reset coils is the unique feature associated with each point

Small-angle scattering in a marginal Fermi-liquid

We study the magnetotransport properties of a model of small-angle scattering in a marginal Fermi liquid. Such a model has been proposed by Varma and Abrahams [Phys. Rev. Lett. 86, 4652 (2001)] to account for the anomalous temperature dependence of in-plane magnetotransport properties of the high-Tc cuprates. We study the resistivity, Hall angle and magnetoresistance using both analytical and numerical techniques. We find that small-angle scattering only generates a new temperature dependence for the Hall angle near particle-hole symmetric Fermi surfaces where the conventional Hall term vanishes. The magnetoresistance always shows Kohler's rule behavior.Comment: 4 pages, 3 figures, Revtex

Phase diagram and quasiparticle properties of the Hubbard model within cluster two-site DMFT

We present a cluster dynamical mean-field treatment of the Hubbard model on a square lattice to study the evolution of magnetism and quasiparticle properties as the electron filling and interaction strength are varied. Our approach for solving the dynamical mean-field equations is an extension of Potthoff's "two-site" method [Phys. Rev. B. 64, 165114 (2001)] where the self-consistent bath is represented by a highly restricted set of states. As well as the expected antiferromagnetism close to half filling, we observe distortions of the Fermi surface. The proximity of a van Hove point and the incipient antiferromagnetism lead to the evolution from an electron-like Fermi surface away from the Mott transition, to a hole-like one near half-filling. Our results also show a gap opening anisotropically around the Fermi surface close to the Mott transition (reminiscent of the pseudogap phenomenon seen in the cuprate high-Tc superconductors). This leaves Fermi arcs which are closed into pockets by lines with very small quasiparticle residue.Comment: 10 pages, 8 figures, latex (revtex4

Symplectic structure for elastic and chiral conducting cosmic string models

This article is based on the covariant canonical formalism and corresponding symplectic structure on phase space developed by Witten, Zuckerman and others in the context of field theory. After recalling the basic principles of this procedure, we construct the conserved bilinear symplectic current for generic elastic string models. These models describe current carrying cosmic strings evolving in an arbitrary curved background spacetime. Particular attention is paid to the special case of the chiral string for which the worldsheet current is null. Different formulations of the chiral string action are discussed in detail, and as a result the integrability property of the chiral string is clarified.Comment: 18 page

Lessons in Failure: The Rice Growers Association Cooperative

This empirical study investigates a large California cooperative's closure and identifies lessons learned that might be useful to other cooperatives. It was found that the cooperative's directors failed to effectively supervise management. In turn, management fell short of expectations to fully evaluate complex business decisions.Agribusiness,

MARKET REFORMS VERSUS STRUCTURAL REFORMS IN RURAL CHINA

This paper adds to the debate on the impact of market reforms versus structural reforms in explaining agricultural output growth in China. A multiple-output stochastic frontier and a technical inefficiency equation are estimated using provincial data on the rural economy from 1986 to 1995. Grain self-sufficiency policies and incomplete market reforms in the 1980s and 1990s led to allocative inefficiency. Agricultural disinvestment shrunk the production frontier and the fragmentation of land holdings reduced technical efficiency. China's rural economic reform is far from being complete.Agricultural and Food Policy, O47, Q12, Q15,

Researching race in a white space: negotiating interviews at white-wedding shows in England

Our research methods case focuses on how, as researchers, we negotiated the topic of race in recruiting participants and conducting interviews for a study about the cultural reproduction of Whiteness at wedding fairs in the UK. Here, we describe some of the challenges and difficulties we encountered in the course of our fieldwork, including: the designing and re-designing of our research tools, negotiating for interviews, and handling difficult interview exchanges. Though semi–structured interviews are commonly used by qualitative researchers in the social sciences, we highlight some of its shortcomings as a tool to investigating issues of race in a White space. Specifically, we draw on the various obstacles that we encountered in conducting this research. These include: dilemmas on condensing interview time and questions and yet gathering substantial information for analysis; the challenges of recruitment at a busy event like a wedding fair; dealing with challenging behaviour and refusals to participate; challenges of talking about race in a White space; and dealing with outright racist participants. We reflect on our experiences and draw attention to how this project compelled us to introspect on our own assumptions and biases as researchers while exposing the existent racism in a ‘colour-blind’ society (Bonilla Silva, 2006)