John Smith - US grants

This research program seeks to acquire new information about the regulation of the delivery of retinol to vitamin A-requiring tissues. Progress in this research area has been seriously limited by a total lack of information about the molecular events involved in the formation of the vitamin A-retinol-binding protein (RBP) complex within the liver and about the subcellular anatomic locus of these events. A multiple approach has been proposed to study these problems. The initial project is designed to define the subcellular site where retinol complexes with RBP in the liver cell. Radioactive retinyl palmitate, with a very high specific activity, will be administered to vitamin A deficient rats, and Triton X-100 extracts of the subfractions of microsomes and Golgi apparatus will be examined by gel filtration chromatography to determine where the retinol-RBP complex is formed. The aim of a second project is to develop an assay with the capability to distinguish between intact and partially degraded RBP, so that the actual levels of intact RBP can be accurately measured. This assay will involve the immunoprecipitation of RBP and separation of the intact and partially degraded RBP by SDS polyacrylamide electrophoresis. This assay will aid in the determination of the subcellular location of the block in the secretion of RBP in vitamin A deficient animals. In the third project retinyl acetate, an enzyme that has a very high probability of regulating the rate of the formation of the retinol-RBP complex, will be isolated and will be characterized with regard to its physical and kinetic properties. In addition studies will be undertaken to determine the subcellular location of retinyl acetate hydrolase within the liver cell and to relate the activity of this enzyme to the rate of mobilization of vitamin A from the liver. Taken together the informaton developed in these studies should define, in part, the mechanisms which control the mobilization of vitamin A from its liver stores, as well as some of the factors which determine and regulate the plasma concentration of vitamin A. These studies should also provide useful new insights into the mechanisms involved in the secretion of plasma proteins in general.

Hypertext is an approach to information management in which data are stored in a network of nodes connected by links. Nodes can contain text, source code, graphics, audio, video, or other forms of data and are meant to be viewed and manipulated interactively. Hypertext '87, to be held November 12-15, 1987 at Chapel Hill, NC, will be the first large workshop/conference devoted to the sub- ject. Individuals with widely differing backgrounds and experi- ence with hypertext will be encouraged to participate in discus- sions of systems, applications, and issues.

This Engineering Research Equipment Grant will enable purchase of a replacement high-power argon ion laser for use by the quantum electronics group at Berkeley (headed by professor Whinnery, Wang, Gustafson and Smith). Current research uses include pumping a colliding-pulse-modelocking (CPM) femtosecond laser system, pumping a dye laser head for generation of a tunable probe beam for making direct measurements of gain coupling of modes in a semiconductor laser, and measurement of the performance of photorefractive crystals in a context of an optical neural network. Several experiments centered around the high power argon ion laser utilize the femtosecond pulse facility. Passively modelocked CPM lasers which are pumped with CW argon ion lasers achieve the shortest optical pulses demonstrated to date, however, low jitter timing synchronication with optical and/or electrical devices is difficult. The Berkeley group has developed a mechanism using a pulsed optical phaselock loop that utilizes a gain switched semiconductor laser which is cross correlated with the femtosecond pulse train at its leading edge, resulting in a time jitter of only 50 femtoseconds. This unique pulsed optical phase lock loop (POPLL) is at the heart of a subpicosecond optical sampling system. It is currently being used to measure and model picosecond optical devices, and to look at stimulus and probe experiment in quantum wells where the stimulus is provided by a synchronous microwave signal.

Building high performance interactive computer systems requires the understanding of the cognitive processes by which users interact with such systems. Unfortunately, capturing and interpreting this information is very difficult. Current user protocol collection strategies are either obtrusive or capture data at too low a level (e.g. individual key strokes). Previous work has shown that a formal cognitive grammar can be a powerful tool in capturing and analyzing users' interaction. Parsing a low level interaction protocol with this grammar can reveal the user's higher level cognitive strategies. Unfortunately, such cognitive grammars are complex and very difficult to develop. The goal of this research is to develop a set of tools an procedures for creating cognitive grammars. The research has three components. The first, is to build a computerized environment for developing cognitive grammars. Second, is to include in that environment facilities to capture and analyze user protocols. And finally the implications of this work in the study of human-computer interaction will be examined.

Students are learning calculus in a laboratory setting that allows experimentation and discovery learning and focuses on concepts rather than manipulations. The laboratory is equipped with IBM PS/2 computers running Derive. The institution will contribute an amount equal to the award.

9202253 Smith This is the first year of a three-year continuing award to investigate how computer users adapt from the use of introductory systems to the use of more advanced systems. This study involves not only the issues related to user adaptation but also to the mediating effects that a computer system can provide. The methodology is based on comparisons of basic and advanced system tasks in the areas of expository writing and of computer programming. The cross-task transfer effects are also examined, as well as any noticeable longitudinal effects in patterns of use and adaption over time as subjects become more familiar with the systems. Variations in the graphical representations of the same structural information are also considered in the sequence of experiments. A methodological issue considered is the direct examination of the effects of the subject's "thinking-aloud" on potential behavioral distortions and completeness and consistency of the protocol data. The extension of current concepts to a more general cognitive architecture based on cognitive modes and strategies, applicable to a number of different intellectual tasks, is a goal of this investigation oriented towards the eventual development of computer systems more consistent with the manner in which users think.

Memphis State University seeks to provide a four-week commuter EAI Young Scholars Program in mathematics and physics for a group of highly promising African American entering 9th grade from the Memphis area. The program will provide 16 participants with research and career exploration experiences through classroom and laboratory activities, field trips, and interaction with various professionals in science and engineering fields. A major goal of the program is to stimulate career interest in mathematics and science through the use of algebra, geometry, trigonometry, and aspects of physics to examine specific laboratory and field problems.

9452727 Daley The Memphis State University seeks to initiate a four-week, commuter EAI, Young Scholars program in engineering science for a group of highly promising African American student entering grade 9. The program will provide 20 participants with research and career exploration experiences through classroom and laboratory activities, field trips, and interaction with various professionals in the science and engineering fields. A major goal of the program is to stimulate career interest in engineering science through the use of algebra, geometry, trigonometry, and aspects of physics to examine specific laboratory and field problems.

This proposal requests the support of one research associate and one student to work with senior participants on topics in quantum chromodynamics (QCD) relevant to ongoing experiments that are carried out at the Brookhaven, Jefferson and Fermi National Laboratories and the Stanford Linear Accelerator Center, as well as at international laboratories present and planned. These experiments, involve colliding nuclei and/or nucleons (protons and neutrons). They test basic properties of matter, through the investigation of how the elementary particles, quarks and gluons, which moved freely at the earliest stages of the expanding universe, became bound ('confined') to make up neutrons and protons (nucleons). Nucleons in turn constitute the nuclei of all atoms. Also, by polarizing (aligning the spin of) nucleons that are collided, experiments shed light on their internal structure in novel ways. QCD is generally accepted as the controlling theory for the formation of nucleons and nuclei, but the mechanisms by which it acts to confine quarks and produce new particles in collisions are not fully understood, and is one of the most important challenges in theoretical physics. The proposed research will help to synthesize and extend existing theoretical methods from elementary particle and nuclear physics in this area during a period in which experiments are being performed and analyzed. Progress resulting from this project may also have impact on several related theoretical areas.

This project will provide an ideal opportunity for broadening contact between the nuclear and high energy communities, and between theory and experiment. It is characterized by integrated research and training, and will provide career-enhancing opportunities for the junior participants. The professional environment of this work will emphasize intra- and inter-field communication.