Attenuation coefficient for tunnelling leaky rays in graded fibres

A simple derivation is given for the attenuation coefficient of leaky rays in a graded fibre of circular cross-section, requiring only geometric-optics and plane-wave concepts in a 2-dimensional medium.     

Videotaped family interaction: Differences reflecting presence and type of child disturbance.

Analyzed behavior during videotaped family interaction in an unstructured situation (interpreted as interpersonally stressful). 20 families contained a disturbed child (aggressive, socially withdrawn, or distractible); 10 were normal control families. Repeated judgments were made on evaluative, directing, and activity dimensions. Analyses of covariance (covariate: amount of talking) showed significant differences between fathers but not mothers or children. Fathers of normal children were evaluatively neutral and nondirecting (suggesting low attempts to control others) and untalkative (suggesting social independence). Fathers of disturbed children showed controlling and/or dependent behavior: (a) fathers of distractible children were evaluatively extreme and talkative; (b) fathers of withdrawn children were neutral, nondirecting, and talkative; and (c) fathers of aggressive children were negatively extreme, directing, and untalkative. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controlled modification and direct characterization of multimode-fiber refractive-index profiles

A combination of controlled annealing and characterization by scanning probe microscopy (SPM) is used to demonstrate that the refractive-index proffle of a commercially available silica-based optical fiber can be accurately reconfigured for use as an evanescent field sensor. The process relies on the controlled relocation of the silica glass dopants across the fiber cross section through heat treatment and the accurate measurement of the resulting dopant redistribution with SPM and differential etching techniques. The effect of variable annealing along a length of fiber is to produce a mode transformer to couple light from a laser source into the sensing region of the fiber.     

An investigation of early research experience and research self-efficacy.

Graduate students in psychology typically report that they either love research or hate research. Despite the fact that most doctoral students in psychology enter some type of clinical practice upon graduation, research is a requirement for all students enrolled in scientist-practitioner programs regardless of their career aspirations beyond graduation. Research advances knowledge in the field of psychology and often guides clinical practice, yet very few psychologists conduct research after graduate school (C. J. Gelso, 1993). Efforts have been undertaken to determine factors that contribute to graduate students' research productivity. One such factor may be research self-efficacy. This study examined the influence of early research experience as a factor to bolster research self-efficacy. Results indicated that supportive peers and mentors contributed to positive research experiences. Additionally, positive team research experiences significantly predicted research self-efficacy. Implications for training programs and students are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the performance of random vector quantization limited feedback beamforming in a MISO system

In multiple antenna wireless systems, beamforming is a simple technique for guarding against the negative effects of fading. Unfortunately, beamforming requires the transmitter to have knowledge of the forward-link channel which is often not available a priori. One way of overcoming this problem is to design the beamforming vector using a limited number of feedback bits sent from the receiver to the transmitter. In limited feedback beamforming, the beamforming vector is restricted to lie in a codebook that is known to both the transmitter and receiver. Random vector quantization (RVQ) is a simple approach to codebook design that generates the vectors independently from a uniform distribution on the complex unit sphere. This correspondence presents performance analysis results for RVQ limited feedback beamforming     

Adult psychological functioning of individuals born with craniofacial anomalies

This study represents an initial investigation into the adult psychological functioning of individuals born with craniofacial disfigurement. A total of 24 men and women born with a craniofacial anomaly completed paper and pencil measures of body image dissatisfaction, self-esteem, quality of life, and experiences of discrimination. An age- and gender-matched control group of 24 non-facially disfigured adults also completed the measures. As expected, craniofacially disfigured adults reported greater dissatisfaction with their facial appearance than did the control group. Craniofacially disfigured adults also reported significantly lower levels of self-esteem and quality of life. Dissatisfaction with facial appearance, self-esteem, and quality of life were related to self-ratings of physical attractiveness. More than one-third of craniofacially disfigured adults (38 percent) reported experiences of discrimination in employment or social settings. Among disfigured adults, psychological functioning was not related to number of surgeries, although the degree of residual facial deformity was related to increased dissatisfaction with facial appearance and greater experiences of discrimination. Results suggest that adults who were born with craniofacial disfigurement, as compared with non-facially disfigured adults, experience greater dissatisfaction with facial appearance and lower self-esteem and quality of life; however, these experiences do not seem to be universal.     

Memory loss resulting from fornix and septal damage: Impaired supra-span recall but preserved recognition over a 24-hour delay.

Despite increasing evidence that the fornix is important for memory, uncertainty remains about the exact nature of subsequent impairments arising from damage to this tract. This uncertainty is often created by pathology in additional brain structures. The present study involved a young man, DN, who had almost complete bilateral loss of the rostral columns of the fornix and much of the surrounding septum in the left hemisphere following the surgical removal of a cavernous angioma. Quantitative MRI analyses of structure size, normalized to intracranial volume, showed no difference in any of the additional brain regions measured, apart from those areas removed to expose the tumor. DN showed a marked, stable anterograde memory impairment that was still present 4 years postsurgery. In contrast, DN performed within normal levels on most tests of recognition memory. This sparing was most striking when given a 24-hr delay between study and test of the Warrington Recognition Memory Test. This recall/recognition dissociation provides further evidence for neuroanatomical divisions within recognition memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)