Consider a database that represents information about moving objects and their location. For example, for a database representing the location of taxi-cabs a typical query may be: retrieve the free cabs that are currently within 1 mile of 33 N. Michigan Ave., Chicago (to pickup a customer). In the military, moving objects database applications arise in the context of the digital battlefield, and in the civilian industry they arise in transportation systems.Currently, moving objects database applications are being developed in an ad hoc fashion. Database Management System (DBMS) technology provides a potential foundation upon which to develop these applications, however, DBMS's are currently not used for this purpose. The reason is that there is a critical set of capabilities that are needed by moving objects database applications and are lacking in existing DBMS's. The objective of our Databases fOr MovINg Objects (DOMINO) project is to build an envelope containing these capabilities on top of existing DBMS's. In this paper we describe the problems and our proposed solutions.
In guinea pigs, the hyperopia present at birth rapidly reduces to emmetropia within the first 3 weeks of age. The emmetropization process in guinea pigs is mainly related to the increase in the vitreous chamber length. This relationship in guinea pigs is similar to that in chickens, tree shrews, primates and humans. The axial development of the vitreous chamber in guinea pigs appears to be associated with tissue growth of the posterior sclera.
In C57BL/6 mouse eyes, myopia developed early and then the refractive error increased rapidly in the hyperopic direction to reach a peak at around 47 days with the major contributing changes being in axial length and corneal curvature.
It was recently demonstrated that chromaticity could affect eye growth and refractive development in guinea pigs but it remained unclear whether correction with spectacle lenses could balance these effects and how retinal responses change with different spectral compositions of light. Three illumination conditions were tested: blue, red and white light. Animals were raised without or with monocular spectacle lenses from three to seven weeks of age. Luminance electroretinograms (ERGs) were recorded to explore retinal responses with the different spectral compositions. In our special colony of pigmented guinea pigs, characterized by residual hyperopia, spontaneous myopia and poor emmetropization, red light induced early thinning of the choroid and relative myopia, compared to white light. Effects of red light could not be suppressed if positive spectacle lenses were worn. ERGs showed that red light failed to elicit robust retinal responses. Blue light inhibited axial eye growth, even when animals were reared with negative lenses. Intensity-matched blue and white light elicited similar a-waves but different b-waves, suggesting that the wavelength of light affects visual control of eye growth through different processing in the inner retina. We hypothesize that blue light might stimulate preferentially the ON pathway to inhibit myopia induced by negative lenses, at least in guinea pigs.
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