Influence of laser phase on 400-Mbit/s coherent optical DPSK system

The influence of laser phase noise on a 400-Mb/s optical DPSK (differential phase-shift keying) system is experimentally investigated with linewidths ranging from 1.2 MHz to 8 MHz. This range corresponds to linewidth to bit rate ratios ϵ of 0.33-2%. The system performance with these nonzero linewidths is evaluated against a negligible linewidth performance baseline. The sensitivity degradation at a bit error rate of 10^-9 increases from 1.8 to 7 dB as ϵ is increased from 0.33-1%. When ϵ is increased beyond 1%, bit error rate floors higher than 10^-9 develop. These findings agree well with the existing theories and allow the generalization of these results to other bit rates, as well as establishing practical criteria for lasers to be used in DPSK systems     

Interpreting children's responses to ambiguous messages: A reply to Robinson and Whittaker (1985).

Responds to E. J. Robinson and S. J. Whittaker's (see record 1985-25142-001) statement that the present author's (see record 1982-05434-001) interpretation of children's responses to ambiguous referential communications could not have been due to the hypothesized performative bias. It is argued that Robinson and Whittaker did not empirically test the hypothesis and so cannot say that their results contradict it. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response to "This porridge is too thin" by Gretchen M. Brown and "Demolishing a ''straw man''" by Elliott J. Rosen (CQ Vol 7, no 2)

We report a case of cutaneous mixed tumor (CMT) composed of tubular branching structures lined by cells with apocrine characteristics. In addition, an apocrine duct in the outer sheath of an hair follicle was connected to the mixed tumor, a previously unreported finding. Follicular and sebaceous differentiation have been described in CMT, leading some observers to suggest the existence of an apocrine type of CMT and its presumed differentiation toward the folliculo-sebaceous-apocrine unit (FSAU). Our case demonstrated continuity of an apocrine duct in the FSAU and lends support to the previous speculations about the histogenesis of apocrine type of CMT.     

Reversible monocular blindness complicating Churg-Strauss syndrome

A 76-year-old woman hospitalized for treatment of an inferior vena cava thrombus was noted to have eosinophilia as well as asthma, peripheral neuropathy, jaw claudication and visual loss. Pathological review of a temporal artery biopsy revealed vasculitis with eosinophils but no giant cells. Treatment with high dose corticosteroids resulted in improvement of visual acuity from hand motion to 20/60. Whereas at least 6 cases of temporal artery involvement with Churg-Strauss syndrome have been reported, visual loss has occurred in only 3 patients. In each of these cases, visual loss was permanent.     

Techniques for the retrieval of aerosol properties over land andocean using multiangle imaging

Aerosols are believed to play a direct role in the radiation budget of Earth, but their net radiative effect is not well established, particularly on regional scales. Whether aerosols heat or cool a given location depends on their composition and column amount and on the surface albedo, information that is not routinely available, especially over land. Obtaining global information on aerosol and surface radiative characteristics, over both ocean and land, is a task of the Multi-angle Imaging SpectroRadiometer (MISR), an instrument to be launched in 1998 on the Earth Observing System EOS-AM1 platform. Three algorithms are described that will be implemented to retrieve aerosol properties globally using MISR data. Because of the large volume of data to be processed on a daily basis, these algorithms rely on lookup tables of atmospheric radiative parameters and predetermined aerosol mixture models to expedite the radiative transfer (RT) calculations. Over oceans, the “dark water” algorithm is used, taking full advantage of the nature of the MISR data. Over land, a choice of algorithms is made, depending on the surface types within a scene-dark water bodies, heavily vegetated areas, or high-contrast terrain. The retrieval algorithms are tested on simulated MISR data, computed using realistic aerosol and surface reflectance models. The results indicate that aerosol optical depth can be retrieved with an accuracy of 0.05 or 10%, whichever is greater, and some information can be obtained about the aerosol chemical and physical properties     

Migration and biodegradation of free silicone from silicone gel-filled implants after long-term implantation

In vivo 1H NMR chemical shift imaging (CSI), 1H NMR localized spectroscopy (STEAM) and multinuclear NMR spectroscopy (29Si, 13C, 1H) were used to characterize the aging process of silicone gel-filled implants in a rat model after long-term implantation. Although no significant changes could be observed in the implants or surrounding tissue by in vivo 1H chemical shift imaging, in vivo 1H localized spectroscopy of the livers from the longer term population revealed the presence of silicone. Ex vivo 29Si spectroscopy of the liver, spleen, and the capsule formed around the 9 and 12 month implants clearly demonstrated and confirmed for the first time that a significant amount of free silicone migrates from silicone gel-filled implants. Also, these results show that silicones are not metabolically inert, and their biodegradation in tissue and within the implant can be monitored after 9 and 12 months by changes in the 29Si chemical shifts seen in corresponding ex vivo spectra. The NMR findings are supported by those obtained by atomic absorption spectroscopy. Silicone aging changes not only the chemical composition of the gel, but also its proton T2 relaxation times, which increase with long implantation times. The three dimensional structure of the gel disintegrates (i.e., polymer chain rupture), increasing the molecular mobility of the polymer and, consequently, its protons T2 values. The relaxation data we obtained reflect this in vivo degradation, especially in the case of implant rupture. Additionally, small concentrations of fat in the silicone gel were found within the implants. The presence of these lipophilic substances also might increase the T2 values (plasticizer effect). These findings may assist in evaluating the implant integrity and disease symptoms related to their presence in humans.     

Black-white differences in risk for cutaneous, ocular, and visceral melanomas

Fair-skinned individuals have a much higher risk of cutaneous and ocular melanomas than dark-skinned individuals, possibly reflecting a protective effect of melanin against sun exposure. There are some reasons to believe that the effect of sunlight exposure is indirect (i.e., sunlight stimulates growth factor production, which then stimulates melanocytic proliferation, leading to melanoma). Visceral melanomas are extremely rare, and little is known about them. This study used US data on 25,184 melanoma cases to investigate the White-Black ratio for visceral melanoma and did not find a disproportionality similar to that for cutaneous and ocular melanomas. The findings support the hypothesis that the sunlight effect on melanoma is primarily direct.     

Maternal relationship instability and the school behavior of children from disadvantaged families.

This longitudinal study examined the relation between the instability of maternal intimate relationships and the school behavior of 3rd-grade children from economically disadvantaged families. After ecological correlates were controlled, chronic relationship instability predicted externalizing behavior for boys and girls and internalizing behavior for girls, but not academic competence. In addition, past and recent instability had independent effects: Recent instability moderated the relation for past instability, and child adjustment in highly unstable families varied with verbal ability and aspects of the family ecology. The theoretical implications concern conceptualizations of the diverse and dynamic nature of family arrangements experienced by disadvantaged children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Augmenting a window system with speech input

Some necessary background in speech recognition and window systems is given, with an analysis of how they might be combined. Xspeak, a navigation application, and its operation and a field study of its use are described. With Xspeak, window navigation tasks usually performed with a mouse can be controlled by voice. An improved version, Xspeak II, which incorporates a language for translating spoken commands, is introduced     

Static and dynamic characteristics of DFB lasers with longitudinalnonuniformity

Static and dynamic characteristics of 1.55-μm distributed-feedback (DFB) lasers with longitudinal nonuniformity in optical intensity and carrier density are discussed. The nonuniformity is manifested in soft light-current threshold and varying differential quantum efficiency, blue-shifted static tuning, and free-carrier induced FM response