Understanding the retinal basis of vision across species

The vertebrate retina first evolved some 500 million years ago in ancestral marine chordates. Since then, the eyes of different species have been tuned to best support their unique visuoecological lifestyles. Visual specializations in eye designs, large-scale inhomogeneities across the retinal surface and local circuit motifs mean that all species' retinas are unique. Computational theories, such as the efficient coding hypothesis, have come a long way towards an explanation of the basic features of retinal organization and function; however, they cannot explain the full extent of retinal diversity within and across species. To build a truly general understanding of vertebrate vision and the retina's computational purpose, it is therefore important to more quantitatively relate different species' retinal functions to their specific natural environments and behavioural requirements. Ultimately, the goal of such efforts should be to build up to a more general theory of vision

REAL-TIME SPECTRALLY EFFICIENT TARGET IMAGING

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaTo enhance the visibility of remote objects under test at Air Force testing facilities in adverse weather conditions, the Air Force Flight Test Center (AFFTC), Edwards AFB, California, contracted with Physical Optics Corporation’s (POC) Applied Technology Division, Torrance CA, to investigate a realtime spectrally enhanced imaging prototype system. When installed on an optical target tracker, this system will automatically adjust its spectral transmission in such a way that the intensity of the background illumination will be reduced significantly while providing minimum reduction of the light reflected from a detected target. A laboratory prototype of this system was developed under a Small Business Innovative Research (SBIR) Phase I contract. The prototype consists of the optical part that will be attached to the large tracker lens and to a portable computer. The key element of this system is an Acousto-Optic Tunable Filter (AOTF) that is capable of quickly varying the shape of its spectral transmission curve in the entire visible range under computer control. The developed system automatically analyzes the spectral signatures of the background and of the selected object of interest. It calculates a spectrally matched filter for the background suppression and target contrast enhancement. This filtered data then goes directly into the optical channel with the minimal computer image processing. The resulting image with the enhanced target contrast can be displayed in real time on a common computer monitor and can be recorded by a VCR. The performance of the laboratory prototype demonstrated enhancement of the visibility of objects immersed in a scattering medium. Successful development of a working system will make flight testing of military equipment more informative and less expensive. It will reduce the dependence of the flight test program on the weather conditions and will allow for collecting more data by providing real-time images with enhanced target visibility.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Insight on polymer electrolytes for electrochemical devices applications

Polymer electrolytes (PEs) are of much attention as potential electrolytes of great technological relevance for solid-state electrochemistry, in particular for their possible practical application in devices such as batteries, supercapacitors, fuel cells, smart windows, sensors, and solar cells, among others. Generically, solid polymer electrolytes (SPEs) are mixtures of salts with basic polymers, such as poly(ethylene oxide) (PEO) or poly(ethylene imine) (PEI). However, there are also other polymers used as matrices for ionic conduction, like poly(vinyl alcohol) (PVA), poly(vinylidene fluoride) (PVDF), or natural macromolecules. A brief description of theoretical aspects of different PEs and past and recent trends in development of these materials are presented in this chapter. SPEs have many advantages including high energy density, no risk of leakage, no deleterious issues related to the presence of solvent, wide electrochemical stability window, simplified processability, and light weight. Some examples of prototypes of electrochromic device (ECD), batteries, supercapacitors, fuel cells, sensors, dye sensitized solar cells (DSSCs), and light emitting electrochemical cells are also presented and discussed in scope of this contribution.- (undefined

Psychometric validation of the obsessive belief questionnaire and interpretation of intrusions inventory - Part 2: Factor analyses and testing of a brief version

The Obsessive Belief Questionnaire (OBQ) and the Interpretation of Intrusions Inventory (III) were designed to assess beliefs and appraisals considered critical to the pathogenesis of obsessions. In previous reports we have described the construction and psychometric properties of these measures. In this study a battery of questionnaires assessing anxiety, depression, and obsessive compulsive symptoms was completed by 410 outpatients diagnosed with obsessive compulsive disorder, 105 non-obsessional anxious patients, 87 non-clinical adults from the community, and 291 undergraduate students. Items from 6 theoretically derived subscales of the OBQ were submitted to factor analysis. Three factors emerged reflecting (1) Responsibility and threat estimation, (2) Perfectionism and intolerance for uncertainty, and (3) Importance and control of thoughts. A 44-item version (OBQ-44) composed of high-loading items from the 3 factors showed good internal consistency and criterion-related validity in clinical and non-clinical samples. Subscales showed less overlap than original scales. Factor analysis of the III yielded a single factor, suggesting the total score be used in lieu of the 3 rationally derived subscales. The scales performed well on tests of convergent validity. Discriminant validity was promising; hierarchical regression analyses indicated that the OBQ subscales and III generally predicted OC symptoms after controlling for general distress. A revision of the OBQ, the OBQ-44, is included in the appendix