Presheaves as Configured Specifications

The paper addresses a notion of configuring systems, constructing them from specified component parts with specified sharing. This notion is independent of any underlying specification language and has been abstractly identified with the taking of colimits in category theory. Mathematically it is known that these can be expressed by presheaves and the present paper applies this idea to configuration. We interpret the category theory informally as follows. Suppose ? is a category whose objects are interpreted as specifications, and for which each morphism u : X→Y is interpreted as contravariant ‘instance reduction’, reducing instances of specification Y to instances of X. Then a presheaf P: Set ^?op represents a collection of instances that is closed under reduction. We develop an algebraic account of presheaves in which we present configurations by generators (for components) and relations (for shared reducts), and we outline a proposed configuration language based on the techniques. Oriat uses diagrams to express colimits of specifications, and we show that Oriat's category Diag(?) of finite diagrams is equivalent to the category of finitely presented presheaves over ?. Received May 1998 / Accepted in revised form August 2000     

Photolithography of amorphous films of (η5-C5H5)2Ti(N3)2 on silicon (111) resulting in TiO2: The mechanism of the photodeposition reaction

Photolithography to produce TiO₂ patterns from amorphous films of (⁵-C₅H₅)₂Ti(N₃)₂ has been demonstrated. The efficiency of the reaction has been measured yielding a quantum yield of 0.025. The mechanism of the photoreactions of (⁵-C₅H₅)₂Ti(N₃)₂ has been studied using Fourier transform-infrared spectroscopy in both a low-temperature 1,2-epoxyethylbenzene glass and as surface films. In each case the primary photochemical process was found to be loss of a single azido group. The result of subsequent photolysis was found to be dependent upon medium and temperature. In the low-temperature glass no further photochemistry was observed. The exhaustive photolysis of films at 20 K, or room temperature, under a vacuum or in air led to loss of all ligands and the formation of TiO₂.     

The Alexandria Digital Library architecture

Since 1994, the Alexandria Digital Library Project has developed three prototype digital libraries for georeferenced information. This paper describes the most recent of these efforts, a three-tier client-server architecture that relies heavily on a middleware layer to present a single uniform set of interfaces to multiple heterogeneous servers. These standard interfaces, all of which are implemented in HTTP, support session management, collection discovery and evaluation, metadata searching, metadata retrieval, and online holding retrieval. An XML-based metadata encoding scheme and a simple Boolean query language have also been developed. The architecture described by these interfaces has been implemented at UCSB.     

Sizing dielectric spheres and cylinders by aligning measured and computed resonance locations: algorithm for multiple orders

An algorithm for determining the size of dielectric spheres and cylinders by aligning measured and computed resonance locations is presented. The orders of the resonance locations need not be known a priori. The algorithm is applicable to several types of scattering and emission spectra of spheres and cylinders if the index of refraction including dispersion is known and uniform, or nearly uniform, throughout the sphere or cylinder. The algorithm performs well when tested with groups of computed resonance locations of spheres (synthetic data) and with measured fluorescence emission spectra of spheres exhibiting as many as 5 orders of resonance.     

The dielectric properties of a commercial polyvinylchloride

The dielectric response of a commercial polyvinylchloride is examined in terms of the cluster model of dielectric relaxation, and compared with a sample from which the plasticizer had been extracted. An interpretation of the approach to the glass transition in terms of scaling concepts is outlined and related to the hierarchical dynamics of the cluster model. In this picture the dynamics goes over naturally to the dynamics on small size scales. The plasticizer is shown to contribute a quasi-d.c. electrical transport above the glass transition, which at higher temperatures causes the formation of an electrode barrier layer.     

A rapid micromethod for measuring theophylline in serum by reverse-phase high-performance liquid chromatography

We describe an assay system for measuring theophylline in 25 microliters of serum. The procedure involves extraction with a 95:5 mixture of chloroform:isopropanol containing beta-hydroxypropyltheophylline as internal standard, and reverse-phase chromatography on a 4 mm x 30 cm column containing "micron Bondapak C18." Theophylline and beta-hydroxypropyltheophylline are eluted with a 90:10 mixture of sodium acetate butter (20 mmoles/litre pH 4.0) and acetonitrile at a flow rate of 1.8 ml/min., are detected by their absorbance at 254 nm, and quantitated by measuring peak areas. Column temperature has not been found to be critical in this analysis. Each analysis requires 9 minutes of chromatography time with a total analysis time of 20 minutes. Analytical recoveries were found to be 71 to 75% for theophylline and 94% for beta-hydroxypropyltheophylline. This difference in recovery is corrected when determining the theophylline concentration in unknown samples. The method has good precision (coefficients of variation between 7.0% and 7.9% for therapeutic and toxic concentrations). The results obtained with this method compare favourably with results obtained by a published cation-exchange high-performance liquid chromatographic method. None of the metabolites of theophylline, common compounds related to theophylline in structure or drugs tested have been found to interfere with the analysis described.     

Atmospheric emission and attenuation in the range 100 to 600 GHz measures from a mountain site

Further measurements of atmospheric emission from a site in the Canary Islands (Izana, âltitude 2.4 km) have been made during the month of August 1980. The measurements were made with a polarising Interferometer and a composite Ge bolometer. An independent measurement of the precipitable water vapour was made using Infrared Hygrometers. The experimental details are described and the spectra obtained are compared with model spectra using the measured precipitable water vapour.     

Psychotherapy with high-achieving adolescent girls.

The "overnurtured child" is the label applied to adolescent girls whose strong mother-identification and oedipal attachment to father may be associated with a variety of achievement-related conflicts following puberty. Symptoms include anxiety, depression, vague feelings of inadequacy, loneliness, and isolation from peers. These patients suffer from a form of identity diffusion in which pressures to continue achieving at their present rate of excellence collide with pressures to be more "feminine," social, and affiliative. Therapy is conceptualized as a kind of resocialization process aimed at facilitating separation from family and the development of an independent identity. In treatment, the therapist plays a variety of interrelated roles such as role model, family counselor, and teacher. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The electroactive species in the catalysis of cyclohexadiene to benzene by Rh2(TM4) 4 +2 (TM4=2,5-diisocyano-2,5-dimethylhexane)

Upon further investigation of the recently reported electrocatalytic oxidation of 1,4-cyclohexadiene to benzene by Rh₂(TM4) ₄ ⁺² (TM4=2,5-diisocyano-2,5-dimethylhexane), we have obtained data which strongly implicates the 2e^– oxidized d⁷-d⁷ complex as the electroactive species. This contrasts with the original report which suggested that the le^– oxidized d⁷-d⁸ radical acted as the key species via hydrogen atom abstraction from 1,4-cyclohexadiene. A possible mechanism for the catalysis is proposed.     

Are lebed’s magic angles truly magic?

We report high-resolution angle-dependent measurements of the Periodic Orbit Resonance (POR) effect in (TMTSF)₂ClO₄. We observe additional harmonic resonances that were not observed in previous studies. By measuring over a broad range of frequency, field, and field orientation, we find that all of the POR evolve from the Lebed magic angles observed in dc (ω=0) AMRO measurements. However, we find that the resonance angles vary with frequency in a manner that can easily be explained using a semiclassical model. This indicates that these angles are not ‘magic’ at frequencies on the order of the cyclotron frequency.