Showing papers by "University of California published in 1991"

Limit laws for Random matrices and free products

Abstract: In earlier articles we studied a kind of probability theory in the framework of operator algebras, with the tensor product replaced by the free product. We prove here that free random variables naturally arise as limits of random matrices and that Wigner's semicircle law is a consequence of the central limit theorem for free random variables. In this way we obtain a non-commutative limit distribution of a general gaussian random matrix as an operator in a certain operator algebra, Wigner's law being given by the trace of the spectral measure of the selfadjoint component of this operator

Absolute and Relative Gains in International Relations Theory

Abstract: The problem of absolute and relative gains divides neoliberal institutionalism and structural realism. The former assumes states focus primarily on their absolute gains and emphasizes the prospects for cooperation. The latter supposes states are largely concerned with relative gains and emphasizes the prospects for conflict. Existing work in international relations theory generally traces the differences between these two theories to different assumptions about states' preferences. Using a simple game-theoretic model, this essay offers a reformulation of the problem of absolute and relative gains that links changes in the states' behavior, the feasibility of cooperation, and especially the states' concern for relative versus absolute gains explicitly to changes in the constraints facing the states. Many of the differences between neoliberal institutionalism and structural realism appear as special cases of the model.

Chimeric chains for receptor-associated signal transduction pathways

Abstract: Chimeric proteins and DNA encoding chimeric proteins are provided, where the chimeric proteins are characterized by an extracellular domain capable of binding to a ligand in a non-MHC restricted manner, a transmembrane domain and a cytoplasmic domain capable of activating a signaling pathway. The extracellular domain and cytoplasmic domain are not naturally found together. Binding of ligand to the extracellular domain results in transduction of a signal and activation of a signaling pathway in the cell, whereby the cell may be induced to carry out various functions relating to the signalling pathway. A wide variety of extracellular domains may be employed as receptors, where such domains may be naturally occurring or synthetic. The chimeric DNA may be used to modify lymphocytes as well as hematopoietic stem cells as precursors to a number of important cell types.

Laser excited confocol microscope fluorescence scanner and method

Abstract: A fluorescent scanner for scanning the fluorescence from a fluorescence labeled separated sample on a sample carrier including a confocal microscope for illuminating a predetermined volume of the sample carrier and/or receiving and processing fluorescence emissions from said volume to provide a display of the separated sample.

Libraries of modified peptides with protease resistance

Abstract: Peptoids are provided which are polymers comprised of monomer units wherein the monomer units include at least some substitute amino acids and may include conventional amino acids. The peptoids can be synthesized in large numbers so as to provide libraries of peptoids which can be screened in order to isolate peptoids of desired biological activity. Certain peptoids are designed to mimic as closely as possible the activity of known proteins. Other peptoids are designed so as to have greater or lesser activity than known proteins and may be designed so as to block known receptor sites and/or elicit a desired immunogenic response and thereby act as vaccines. A range of different amino acid substitutes are disclosed, as are their methods of synthesis and methods of using such amino acid substitutes in the synthesis of peptoids and peptoid libraries. Methods of screening the libraries in order to obtain desired peptoids of a particular biological activity are also disclosed. The peptoids are preferably linked to a pharmaceutically active drug forming a conjugate with increased binding affinity to a particular biological receptor site.

A placebo-controlled trial of maintenance therapy with fluconazole after treatment of cryptococcal meningitis in the acquired immunodeficiency syndrome. California Collaborative Treatment Group.

Abstract: Background and Methods. In patients with the acquired immunodeficiency syndrome (AIDS), the rate of relapse after primary treatment for cryptococcal meningitis remains high. We conducted a controlled, doubleblind trial to evaluate the efficacy of maintenance therapy with fluconazole. At entry into the study, all participants had sterile cultures of cerebrospinal fluid, blood, and urine after following a standardized course of therapy for culture-proved cryptococcal meningitis. The patients were randomly assigned to take either fluconazole or placebo as maintenance therapy. The dose of fluconazole was 100 mg daily in the first phase of the study and 200 mg daily in the second phase. Results. Of 84 patients initially enrolled, 16 (19 percent) were found to have silent, persistent infection on the basis of cultures that became positive after entry into the study; 7 other patients were lost to follow-up shortly after entry. Of the remaining 61 patients, 10 of 27 assigned to placebo (37 percent) and 1...

Translating Coping Theory into an Intervention

Abstract: During the 1980s, the Berkeley Stress and Coping Project conducted a number of studies about the coping process based on a cognitive theory of stress and coping (Lazarus, 1966; Lazarus & Folkman, 1984). These studies furthered understanding of the coping process, including its multidimensionality, the contextual person and environmental factors that influence it, and its relationship to emotions, psychological wellbeing, and physical health (e.g., Folkman & Lazarus, 1980, 1985, 1986; Folkman, Lazarus, Dunkel-Schetter, DeLongis, & Gruen, 1986).

Low temperature thin films formed from nanocrystal precursors

Abstract: Nanocrystals of semiconductor compounds are produced. When they are applied as a contiguous layer onto a substrate and heated they fuse into a continuous layer at temperatures as much as 250, 500, 750 or even 1000° K below their bulk melting point. This allows continuous semiconductor films in the 0.25 to 25 nm thickness range to be formed with minimal thermal exposure.

Microbial production of plant hormones

Abstract: Our laboratory has focused on microbial production of plant hormones and precursor-inoculum interactions. Indole-3-acetic acid was detected in soils incubated with L-tryptophan (L-TRP). Inoculation with the ectomycorrhizae, Pisolithus tinctorius significantly stimulated the growth of Douglas fir when supplied with low concentrations of L-TRP to soil. Among three Azotobacter spp. and two Pseudomonas spp., the most prolific producer of cytokinins was A. chroococcum and among the precursors tested, adenine (ADE) and isopentyl alcohol (IA) were the most effective. Corn rhizosphere was found to be quite rich with microflora capable of producing ethylene from L-methionine (L-MET). Amino acids, carbohydrates and organic acids typically found in root exudates, were stimulatory to ethylene biosynthesis in soil. Etiolated pea seedlings exhibited the classical ‘triple’ response when L-MET and Acremonium falciforme were applied in combination to sterile soil or when L-MET was added to nonsterile soil.

Particle-laden turbulent flows: direct simulation and closure models

Abstract: This paper presents an overview of the state-of-the-art of direct numerical simulation (DNS) and closure models of particle-laden turbulent flows. The paper also shows how the results of direct simulation can be used to improve current closure models of these flows. Particle dispersion in a decaying grid-turbulence is studied using DNS, and the results are compared with the measurements of Snyder and Lumley (1971).

Sequence Evolution of Mitochondrial DNA in Humans and Chimpanzees: Control Region and a Protein-Coding Region

Abstract: Complete primary structures for the major non-coding region of 13 human and two chimpanzee mitochondrial DNAs (mtDNAs) were determined by direct sequencing via the polymerase chain reaction and compared to published sequences for one other human and two other chimpanzees. The human mtDNAs were chosen to represent the deepest branches found in a genealogical tree relating the restriction maps of 182 types of mtDNA. With the four chimpanzee sequences as outgroups, it was possible to place a root on the tree relating the human sequences. This root is consistent with the idea of an African origin for human mtDNA but does not rule out alternative hypotheses. Our sequences confirm a previous finding that the probability of substitution varies greatly among sites in the control region, some sites being so variable that they have probably changed many times since chimpanzees and humans had a common ancestor. In addition, our results show that the pattern of substitution in the control region has diverged since chimpanzees and humans had a common ancestor. These two observations may help to explain why it is hard to root the human tree with chimpanzee sequences as well as to determine the time of common ancestry for humans using the control region. Therefore, sequences were also obtained for a more slowly-evolving part of mtDNA, viz an 896-bp segment which includes parts of the genes for NADH dehydrogenase subunits 4 and 5. They show that the extent of divergence among humans in this segment of mtDNA is less than 3/79 of that between humans and chimpanzees. This result reinforces estimates based on restriction mapping that the last common ancestor of the humans sampled existed less than 200,000 years ago.

Update: ansa cervicalis to recurrent laryngeal nerve anastomosis for unilateral laryngeal paralysis.

Abstract: Twenty cases of unilateral laryngeal paralysis are reported. Satisfactory follow-up intervals and data (videostroboscopy and glottographic analysis) were available on 12 patients. The excellent to normal phonatory quality achieved in many of these patients indicates that the ansa cervicalis to recurrent laryngeal nerve anastomosis is the procedure of choice in selected patients with unilateral vocal cord paralysis. Excellent medialization of the paralyzed cord, as well as correction of arytenoid malposition and thyroarytenoid muscle atrophy appear to explain the technique's success, since the reinnervated cord neither abducts nor adducts. We feel that this technique is the procedure of choice in younger patients, or those who use their voices professionally, since the phonatory quality achieved is superior to Teflon injection or Isshiki thyroplasty, and the technique is reversible.

Rearrangements of mitochondrial transfer RNA genes in marsupials

Abstract: The nucleotide sequences of the mitochondrial origin of light-strand replication and the five tRNA genes surrounding it were determined for three marsupials. The region was found to be rearranged, leaving only the tRNA(Tyr) gene at the same position as in placental mammals and Xenopus. Distribution of the same rearranged genotype among two marsupial families indicates that the events causing the rearrangements took place in an early marsupial ancestor. The putative mitochondrial light-strand origin of replication in marsupials contains a hairpin structure similar to other vertebrate origins and; in addition, extensive flanking sequences that are not found in other vertebrates. Sequence comparisons among the marsupials as well as placentals indicate that the tRNA(Tyr) gene has been evolving under more constraints than the other tRNA genes.

Endoscopic knot tying apparatus and methods

Abstract: A suture applying and tying device comprises at least one grasping device for securing a length of suture, a second grasping device for forming a loop in a length of the suture, and a pushing rod for advancing the loop towards tissue

Apparatus and method for measuring fluorescence intensities at a plurality of wavelengths and lifetimes

Abstract: Apparatus and method for measuring intensities at a plurality of wavelengths and lifetimes. A source of multiple-wavelength electromagnetic radiation is passed through a first interferometer modulated at a first frequency, the output thereof being directed into a sample to be investigated. The light emitted from the sample as a result of the interaction thereof with the excitation radiation is directed into a second interferometer modulated at a second frequency, and the output detected and analyzed. In this manner excitation, emission, and lifetime information may be obtained for a multiplicity of fluorochomes in the sample.

Rapid solid-state synthesis of refractory materials

Abstract: A process for producing a refractory material having the form TB o , e.g. zirconium nitride (ZrN), includes a first step of mixing a first salt having the form TX n , e.g. zirconium tetrachloride (ZrCl 4 ) and a second salt having the form A m B, e.g. lithium nitride (Li 3 N) in a ratio of n/m in a container. The process also includes a second step of igniting the mixture of the first and second salts, e.g. ZrCl 4 and Li 3 N, whereby the refractory material, e.g. ZrN, is produced along with byproducts having forms nAX and (n/m-o)B, e.g. 4LiCl and (1/6)N 2 , respectively. The process further includes a third step of separating the refractory material from the byproducts by solvent extraction. The stoichiometric ratio of the second salt to the first salt is n/m, e.g. 4/3. T is selected from the group consisting of transition metals, e.g. zirconium, and tetrelides, i.e. carbon, silicon, germanium, tin and lead. X is selected from the halide group consisting of fluorine, chlorine, bromine and iodine. A is selected from the group consisting of alkali metals, i.e. lithium, sodium, potassium, rubidium and cesium, and alkaline earth metals, i.e. beryllium, magnesium, calcium, strontium and barium. B is a base selected from the group consisting of pnictides, i.e. nitrogen, hosphorus, arsenic, antimony and bismuth, and tetrelides, i.e. carbon, silicon, germanium, tin and lead, m and n are integers and o is a fraction, e.g. 3/3=1.

Algorithms for synthesis of hazard-free asynchronous circuits

Abstract: A teclinique for the synthesis of asynchronous sequential circuits from a Signal Transition Graph (STG) specificatmion is described. We give algorithms for synthesis and hazard removal, able to produce hazard-free circuits with the bounded wire-delay model, requiring the STG to be live, safe and to have the unique state coding property. A proof tliat, contrary to previous beliefs, STG persistency is not necessary for hazard-free implementation is given.

A method for producing metal oxide aerogels having densities less than 0.02 g/cm?3

Abstract: A two-step method is described for making transparent aerogels which have a density of less than 0.003 g/cm3 to those with a density of more than 0.8 g/cm3, by a sol/gel process and supercritical extraction. Condensed metal oxide intermediate made with purified reagents can be diluted to produce stable aerogels with a density of less than 0.02 g/cm3 including densities lower than 0.003 g/cm3. High temperature, direct supercritical extraction of the diluted alcogels produces hydrophobic aerogels which are stable at atmospheric moisture conditions. Monolithic, low density homogeneous silica aerogels have high thermal insulation capacity, improved mechanical strength and good optical transparency.

Loblolly Pine (Pinus taeda L.)

Abstract: Loblolly pine (Pinus taeda L.) is the leading commercial timber species in the southern United States. Carolus Linnaeus gave loblolly pine its scientific name, Pinus taeda, over 225 years ago. Taeda is the ancient name for resinous pines. It comes from the Latin, meaning torch. In Roman times, taeda was applied to several of the hard, pitchy pines (Wahlenberg 1960).

Adrenergic hormones and control of cardiac myocyte growth

Abstract: The molecular mechanisms of cardiac myocyte growth are relevant to important problems in cardiovascular disease. A cell culture model has been developed to explore the role of adrenergic hormones in cardiac myocyte growth and gene expression. Activation of a cardiac myocyte α1-adrenergic receptor by catecholamines induces hypertrophic growth of neonatal rat cardiac myocytes and initiates selective increases in contractile protein gene transcription. These effects on growth and gene expression do not depend on contractile activity. The cardiac myocytes contain at least two subtypes of α1-adrenergic receptors and at least three isoforms of protein kinase C (PKC). A distinct α1 receptor subtype may mediate hypertrophy and gene transcription. Different isoforms of PKC are translocated to different intracellular sites on activation, and there is evidence that the β-PKC isoform may be an element in the signal transduction pathway from an α1 receptor at the surface to the cardiac myocyte nucleus. Growth regulation through a β-adrenergic receptor can also be demonstrated in the culture model. The growth response mediated through a β-adrenergic receptor differs in several respects from that transduced through an al adrenergic receptor.

Plate-mode ultrasonic structure including a gel

Abstract: An ultrasonic structure which has a thin planar sheet of material forming a Lamb wave propagation medium The propagation medium is coated with a gel. The structure may also include a Lamb wave generator for generating Lamb waves in the propagation medium and an output device for producing an electrical signal representative of the propagation characteristics of the Lamb waves propagating along the propagation medium. A measuring device can be included to measure selected characteristics of the output electrical signal. The propagation medium has some physical characteristics that are determined by the value of a measurand acting on the medium and the determined physical characteristics determine the propagation characteristics of the Lamb waves which are propagated along the medium. When the sensor is acted on by a measurand to determine the physical characteristics of the propagation medium, the characteristics of the electrical signal are also determined. The measuring device measures the electrical signal and provides an indication of the measurand value.

Marine-Resource Value and the Priority of Coastal Settlement: a California Perspective

Abstract: The value of marine resources and coastal environments to hunter-gatherers has long been debated, with the archaeological record frequently invoked as the ultimate test for various arguments. Optimal-foraging principles suggest that the temporal priority of the exploitation of one resource over another indicates its value with respect to subsistence efficiency, a crucial variable in overall reproductive success. If coastal habitats are highly valuable, their exploitation should be seen early in the archaeological record; if not, a time lag should be evident between the initial exploitation of terrestrial and coastal environments. A review of the archaeology of early marine-resource use in prehistoric California reveals complex patterning that does not exclusively support one position or the other. Certain of these data accommodate the traditional model of an adaptive transition between specialized hunting of terrestrial big game during the Paleoindian period and diversification, including marine-resource exploitation, during the Archaic period. Others, however, suggest that shellfish were part of the diet of the initial colonists of western North America, indicating the value of this resource to mobility-restricted members of hunting and gathering groups.

Techniques for automatic memoization with applications to context-free parsing

Abstract: It is shown that a process similar to Earley's algorithm can be generated by a simple top-down backtracking parser, when augmented by automatic memoization. The memoized parser has the same complexity as Earley's algorithm, but parses constituents in a different order. Techniques for deriving memo functions are described, with a complete implementation in Common Lisp, and an outline of a macro-based approach for other languages.

Adhesion of Fungi to the Plant Surface

Abstract: The initial process of attachment of fungal propagules to a host plant is essential to the successful establishment of pathogenesis. Attachment may be involved in recognition of the host surface, serve as a base around which the infection court can be altered, and may include adhesion of the propagule. It was considered initially that attachment was purely a chance event resulting from physical entrapment of the propagule or germling. We know now that attachment involves an active process of secretion of adhesive materials by the fungus that in some cases are highly specific for the recognition of, and binding to, a particular host species. Adhesive production may occur at a specific stage of conidium or germling development, but may best be considered a general phenomenon for the establishment of the fungus prior to penetration.

Detection of analytes using fluorescent energy transfer

Abstract: The invention provides labeled proteins suitable for determining the presence of cAMP, other second messengers and organic molecules. The proteins are separately labeled with fluorochromes which, when in close spatial proximity, preferably, less than about 6 nm, interact through the transfer of energy from one fluorochrome to the other. A composition of matter (S1kA)n1(S2kD)n2 is provided wherein S1 and S2 are two proteins which are associated in one state and substantially disassociated in another, the equilibrium between which is controlled by the free concentration of an analyte, and A and D are fluorochromes, the emission wavelength of fluorochrome D overlapping the excitation wavelength of fluorochrome A and the distance between A and D being in sufficiently close proximity to allow radiationless transfer of energy between the fluorochromes. A and D can be selected from a variety of acceptor, donor pairs such as fluorescein and tetramethylrhodamine.

Rice Bran: Chemistry and Technology

Abstract: Rough rice, or paddy, consists of a white starchy endosperm kernel surrounded by a tightly adhering bran coat, an adhering germ with the total enclosed within a loose outer hull or husk. All rice is milled before consumption, producing hull, bran, germ, and white rice. Although a small amount of rice is consumed as brown rice, which still contains the bran and germ, white rice is the principal food staple of over 2.5 billion people worldwide.

An experimental study of Froude number effect on wind-tunnel saltation

Abstract: The simulation of the natural process of saltation in a wind tunnel is considered. The pioneering interactive boundary-layer analysis of Owen and Gillette [11] concluded that an independence Froude number criterion did apply to the problem and they estimate, based on wind-tunnel Froude number data ranging from 35 to 80, an independence Froude number value of about 20 for saltating flows to be free of facility constraints imposed on the saltation. The present experimental flows had Froude numbers ranging from about 6 to 1000. Analysis of friction speed variation as a function of downstream position suggests a more conservative critical Froude number value of 10 be used. Also, there appears to be an additional requirement, for most of our data, that tunnel’s downstream length-to-heigt ratio be greater than 5. Therefore, a maximum Froude number of 10 and minimum tunnel length-to-height ratio of 5 is suggested to insure accurate saltation tunnel simulation.