Optical Properties of Doped Antiferromagnets

We investigate the consequences of an incommensurate magnetic order in doped La_2–x Sr _x CuO₄ using dynamical mean-field theory for the effective single-band model. The high-energy optical transitions are due to high-energy excitations across large Mott–Hubbard gap, while low-energy excitations involve a pseudogap induced by the local spin order. The latter lead to a strong drop in the scattering rate at low , in qualitative agreement with the experimental data.     

Conditioned and unconditioned fear organized in the inferior colliculus are differentially sensitive to injections of muscimol into the basolateral nucleus of the amygdala.

Chemical stimulation of the inferior colliculus (IC) with semicarbazide--an inhibitor of the gamma aminobutyric acid synthesizing enzyme--functions as an unconditioned stimulus in the conditioned place aversion test (CPA), and electrolytic lesions of the basolateral amygdala (BLA) enhance the aversiveness of the IC stimulation. This study examined the effects of inactivation of the BLA with muscimol on the conditioned and unconditioned fear using semicarbazide injections into the IC of rats subjected to conditioned (CPA) or unconditioned (open field) fear tests. In both tests, the rats were injected with semicarbazide or saline into the IC and muscimol or saline into the BLA. Muscimol decreased the CPA and increased the unconditioned fear elicited by IC injections of semicarbazide. These findings indicate that distinct modulatory mechanisms in the BLA are recruited during the conditioned and unconditioned fear triggered by IC activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification and approximation of queueing systems

A distance-measures approach to the problems of identification and approximation of queueing systems is presented. This approach combines ideas from statistical robustness, information-type measures, and parameter-continuity of stochastic processes.     

Refusal to eat in the elderly

Refusal to eat by the elderly, and subsequent malnutrition, occurs in both institutional and community settings. Causes include physiologic changes associated with aging, mental disorders such as dementia and depression, and medical, social, and environmental factors. Treatment approaches call for management of these causes while considering the roles that medicine, ethics, and culture play in the process.     

Spectroscopic characterization of 1,5-diphenyl-3,7-dihydroxy-1,5-diazacyclooctane — (8C ring compound) formed in N,N-diglycidylanaline/aniline curing systems

Summary A NMR and infrared analysis of the cyclic product formed by the reaction of N,N-diglycidylaniline with aniline confirms the structure of an eight-membered ring (I). The conformational structure of this compound is discussed.     

Dermatofibrosarcoma protuberans and the Bednar tumor: treatment in the pediatric population

Dermatofibrosarcoma protuberans (DFSP) is a low-intermediate-grade cutaneous sarcoma that has a marked propensity for local recurrence after excision. The Bednar variant of this tumor is even less common and is distinguished histologically by the dispersal of melanin containing cells in an otherwise typical DFSP. Both are considered to be tumors of the third and forth decades of life, but both DFSP and the Bednar variant have been described in children. Until this report of a congenital Bednar tumor, only the DFSP has also been described in the neonate. The histopathology and surgical management of DFSP and Bednar tumors are outlined with emphasis on reported experience in the pediatric population. The surgical management of these lesions in children is based on numerous series in adults and the limited pediatric experience. The recommended treatment is wide excision with 3-cm margins of visibly uninvolved tissue and inclusion of superficial fascia.     

Barriers to the adoption of an energy efficient technology

Solid state electronic ballasts promise significant energy savings in the lighting systems of large buildings. However, organizational factors and standard operating procedures may inhibit the adoption of this technology in the large, bureaucratic public and private sector organizations which represent the major potential users of this technology.     

Effect of hold times on crack retardation in aluminum alloys

Hold time effects on fatigue crack retardation in two high strength aluminum alloys (2219 and 7075) were studied for different metallurgical conditions. Experiments were performed in humid air as well as in vacuum. It was observed that as the hold time at zero load increased, the number of delay cycles decreased in general. This observation is then explained in terms of a strain relaxation phenomenon and a crack closure model. The data indicates that the relaxation effects were greater in humid air than in vacuum. Some visual evidence of surface hammering during retardation was found.