Showing papers by "University of California published in 1973"

The Proper Treatment of Quantification in Ordinary English

Abstract: The aim of this paper is to present in a rigorous way the syntax and semantics of a certain fragment of a certain dialect of English. For expository purposes the fragment has been made as simple and restricted as it can be while accommodating all the more puzzling cases of quantification and reference with which I am acquainted.1

Hedges: A Study In Meaning Criteria And The Logic Of Fuzzy Concepts

Abstract: Logicians have, by and large, engaged in the convenient fiction that sentences of natural languages (at least declarative sentences) are either true or false or, at worst, lack a truth value, or have a third value often interpreted as ‘nonsense’. And most contemporary linguists who have thought seriously about semantics, especially formal semantics, have largely shared this fiction, primarily for lack of a sensible alternative. Yet students of language, especially psychologists and linguistic philosophers, have long been attuned to the fact that natural language concepts have vague boundaries and fuzzy edges and that, consequently, natural language sentences will very often be neither true, nor false, nor nonsensical, but rather true to a certain extent and false to a certain extent, true in certain respects and false in other respects.

The Theory of Shells and Plates

Abstract: A plate and more generally a shell is a special three-dimensional body whose boundary surface has special features. Although we defer defining a shell-like body in precise terms until Sect. 4, for the purpose of these preliminary remarks consider a surface—called a reference surface—and imagine material filaments from above and below surrounding the surface along the normal at each point of the reference surface. Suppose further that the bounding surfaces formed by the end points of the material filaments are equidistant from the reference surface. Such a three-dimensional body is called a shell if the dimension of the body along the normals, called the thickness, is small. A shell is said to be thin if its thickness is much smaller than a certain characteristic length of the reference surface, e.g., the minimum radius of the curvature of the reference surface for initially curved shells.2

Coding properties of two classes of afferent nerve fibers: high-frequency electroreceptors in the electric fish, Eigenmannia.

Abstract: THE PROPOSITION THAT neurons can encode information about the intensity of stimuli in other ways than by the familiar gradation of intervals between impulses has been put forward (5, 6, 12). Perkel and Bullock (23) catalog the known and the candidate codes by which neurons can represent information in streams of nerve impulses. For none of these, other than the familiar frequency coders, is a quantitative characterization available of the behavior of the impulse train as a function of intensity.

Articulated two-part prosthesis replacing the knee joint

Abstract: The invention provides a two-part knee prosthesis comprising components which, respectively, are implanted in the distal end surface of the femur and the proximal end surface of the tibia and which co-operate to provide a substituted articulated knee joint. The femoral component has an upwardly directed anterior fin for upward driven implantation into the distal part of the femur shaft and two transversely spaced femoral condyle replacement support members each of which has a downwardly directed bearing surface which is curved in cross section and in side elevation, the curvature in side elevation being on successively decreasing radii from the anterior portion to the posterior portion of the prosthesis. The tibial component is generally circular and flat in configuration whereby it will lie on the prepared proximal surface of the tibia and its upper surface has a circular upwardly facing groove therein which receives the two transversely spaced femoral condyle replacement support member surfaces of the femoral prosthesis.

Kinetics of Drug-Drug Interactions

Abstract: Open any current medical journal and one is reminded that the coadministration of two or more drugs can either cause deleterious effects or lead to ineffective therapy. Those concerned with drug therapy are increasingly aware of this phenomenon but are confronted with the problem that a patient may be taking three, four, and, on occasion, even more drugs simultaneously. The computer will aid in the storage and retrieval of such information and act as a useful early warning signal, but prudent multiple drug therapy, if deemed necessary, can only be achieved with a better understanding of the nature and quantitative aspects of drug interactions. A drug interaction might broadly be defined as any reaction between one drug and another substance within or out of the body. In this review, the definition is restricted to events occurring within living systems with major emphasis on the alteration by one drug on the rate and extent of absorption, distribution, metabolism, and excretion of another. Prescott (1969) has called these “pharmacokinetic interactions” to distinguish them from the numerous interactions between drugs at their sites of action (Morrelli, 1970). This distinction is somewhat arbitrary as any or all possibilities can occur in vivo. The interaction may be direct, such as the competitive inhibition of drug metabolism and the displacement of a drug from binding sites, or it may be indirect. One example of the latter is the decreased renal clearance of acids, whose renal clearance is sensitive to urinary pH, produced when the urine is rendered alkaline using either the carbonic anhydrase inhibitor, acetazolamide, or sodium bicarbonate.

Abstracts of Contributed Papers

Abstract: The strength of the K line of singly ionized calcium has been measured for several hundred A-type stars within a few hundred parsecs of the Sun and for the A stars in several galactic star clusters. The derived abundance of calcium varies from star to star by up to a factor of 2, and there is no correlation of abundance with the space motion of the stars.

Impact Response of the Human Thorax

Abstract: Part I — Biomechanics Response Data — Thoracic impact response data for unembalmed human cadavers previously published by three of the authors are reviewed These data are then “averaged,” adjusted to reflect an estimate for muscle tensing, and used as the basis for recommended force-deflection corridors to serve as dummy design guidelines A volunteer study of muscle tensing, as related to thoracic stiffness at low force and deflection levels, is discussed, and comments are made concerning additional response data recently acquired by other investigators Finally, consideration is given to possible “second order” refinements for future generations of a high fidelity dummy thorax

Transition Metal Alloys of Extraordinary Stability; An Example of Generalized Lewis-Acid-Base Interactions in Metallic Systems

Abstract: The Engel theory of metals predicts unusually high thermodynamic stability for certain classes of alloys of transition metals for which generalized Lewis-acid-base interactions are possible. To test these predictions, phase equilibria were studied for ternary systems of Zr, C, and the transition metals Re, Ru, Os, Rh, Ir, Pd, Pt, Ag, and Au. Similar literature data for Nb, Ta, Hf, Th, Y, Ce, Er, and Pu with Re, Ru, Rh, Ir, Pt, and Au were evaluated. Thermodynamic data for the carbides of Zr, Hf, Th, Nb, Ta, U, and Y were critically evaluated, tabulated for 1200 to 2300 K, and used to fix the Gibbs energies of formation in kcal/g-atom of alloy, or their limits, for the binary phases of the above metals. In addition, for Zr, activity coefficients and excess Gibbs energies are tabulated. The predicted high stabilities for alloys of Rh, Ir, Pd, and Pt are confirmed with excess Gibbs energies ranging to —100 kcal/g-atom and activity coefficients as low as 10-12 for zirconium or hafnium in dilute solutions of platinum at 1800 K. Some of the properties of these unusually stable compounds have been measured.

Re-establishment of electrophysiologically functional entorhinal cortical input to the dentate gyrus deafferented by ipsilateral entorhinal lesions: Innervation by the contralaeral entorhinal cortex

Abstract: We have unilaterally ablated the entorhinal cortex of the developing rat, thereby removing the major synaptic input to the ipsilateral dentate gyrus. We have then examined the efferent projections of the remaining contralateral entorhinal cortex to determine if these might reoccupy the synaptic territory vacated by the ipsilateral entorhinal fibers. By placing lesions in the remaining contralateral entorhinal cortex, and tracing the resulting degeneration products, we show that the contralateral entorhinal projection is reorganized, establishing an anomalous terminal projection to the dentate gyrus deafferented by the initial lesion. The result is a contralateral entorhinal innervation of the dentate gyrus which normally receives only ipsilateral entorhinal afferents. In addition, we investigate the functional capacity of these anomalous contralateral projections. We show that stimulation of the entorhinal cortex in the normal animal never results in short latency activation of the granule cells contralateral to the stimulating electrode, whereas in the lesioned animals, the contralateral entorhinal stimulation results in a short latency, apparently monosynaptic, evoked potential in the dentate gyrus which had been deprived of its ipsilateral entorhinal innervation. Furthermore, this stimulation results in the discharge of cells in the granule cell layer. Therefore, following unilateral entorhinal lesion, the remaining contralateral entorhinal cortex extends its efferent projection to establish electrophysiologically functional synapses with the granule cells deafferented by the initial lesions.

Cadmium residues in the environment

Abstract: Cadmium (Cd) is a potentially hazardous pollutant in the environment based upon observations of increasing emissions from production and waste-disposal operations, long-term persistence in the environment, and rapid uptake and accumulation of injurious concentrations by plants and animals Chronic human exposure to low concentrations of cadmium in the atmosphere, water, or food may cause serious illness and possibly death Production and consumption of cadmium is continuing to expand throughout the industrialized world As a result, there is a critical need for understanding sources of emissions and their direct or indirect interactions with soil, water, plants, and animals so that criteria may be developed for assessing hazards

Two-Neutron Transfer Reactions and the Pairing Model

Abstract: The description of many-body systems at low energy in terms of “elementary modes of excitation” (see, e.g., Noz 65) is very useful in the case of nuclei (see BM 69). “Elementary modes of excitation” as used here comprise collective (rotations and vibrations) as well as quasiparticle excitations. In order to study the various modes, experiments are required which selectively excite one such degree of freedom while all the others remain inactive spectators.

Bifurcation of periodic solutions into invariant tori: The work of Ruelle and Takens

Abstract: The purpose of this lecture is to discuss a theorem of D. Ruelle and F. Takens [4] which extends Hopf's bifurcation theory. Hopf's bifurcation theory analyzes what happens when an equilibrium point of a differential equation depending on a parameter changes from stable to unstable at a critical value of the parameter. We shall be concerned with what happens when a stable periodic solution becomes unstable. What Ruelle and Takens show is that~ under suitable technical conditions~ a stable invariant two-dimensional torus appears in the vicinity of the unstable closed orbit. It may be helpful to visualize this torus as a tube * containing the closed orbit in its interior~ although this picture is not quite accurate in more than three dimensions (since a torus in n-dimensional space, n ~ 4 ~ does not divide the space into an inside and an outside). The result of Ruelle and Takens is incomplete in that it leaves the nature of the motion on the invariant torus completely obscure. We shall begin by giving the stability analysis for periodic solutions in a form slightly different from that given in Sattinger's lectures. We shall describe the analysis for a smooth ordinary differential equation on Euclidean space; it will be apparent that it applies to at least some partial differential equations as well. Consider the equation

Solar radiation and urban heat islands

Abstract: A model which attempts to simulate urban absorption of solar radiation is concerned with direct solar radiation, diffuse sky radiation, diffuse radiation reflected by buildings and streets, and the shortwave energy absorbed by typical urban structures. The ratio between solar radiation absorbed by three-dimensional building-street systems and two-dimensional horizontal surfaces under cloudless conditions indicates that cities undergo great variations with latitude and season. High structure systems absorb more than six times the radiation of nonurban plains. Shading effects can create absorptance less than that of a level surface. Observations at street level may lead to erroneous conclusions concerning the energy input for the total urban interface. The examination of a circular synthetic city with varying latitudinal radiation responses indicates that daytime urban heat islands are migratory phenomena and probably influence convective air circulation in the city, that downtown areas often absor...

Pair Production by Relativistic Electrons from an Intense Laser Focus

Abstract: A preliminary discussion is given of electron-positron pair production by means of electrons accelerated to relativistic velocities at the focus of a laser beam. First, the pair cross-section was numerically evaluated near its energy threshold. Then, two methods of relativistic electron production by focused laser light were considered: the coherent oscillation of electrons, and the acceleration of a few high velocity electrons by plasma waves excited by laser-driven instabilities. It was found that the first method would produce pairs for neodymium laser light which is close to the limits of achievable intensities (1019–1020 W/cm2). The second method, however, may be capable of producing pairs at lower intensities.

Diffusion of hydrogen in titanium alloys due to composition, temperature, and stress gradients

Abstract: A theoretical and experimental study was conducted to determine the combined effects on interstitial diffusion in metals of gradients in interstitial concentration, in solvent composition, in stress, and in temperature. The theory consolidates relationships, some of which have been previously published. It is based on macroscopic irreversible thermodynamics, and is applicable to anisotropic or Isotropic materials. Experiments were conducted and literature analyzed to determine the numerical quantities required to predict the change in hydrogen distribution with time for pure and alloy titanium, where the solvent gradient, stress gradient, and temperature gradient are constant with time. The diffusion driving forces for solute gradient, solvent gradient, and stress gradient are related to the effect of each factor on hydrogen activity. In addition, the material property which determines the diffusion driving force of a stress gradient for anisotropic material is a matter tensor analogous to the scalar partial molal volume used for isotropic material. The experiments, conducted with commercially pure titanium and titanium alloy, 6A1-4V, consist of measuring the effect of alloy additions and stress on the hydrogen activity in solid solution and the dilatation effect of hydrogen. Stress states tested were tension, compression, and torsion. The measurements were made by exposing titanium and the alloy to hydrogen at temperatures from 600° to 800° C, and measuring the equilibrium hydrogen gas pressure at various solid solution hydrogen contents. Both materials were tested with and without stress. Tension decreased the activity, compression increased it, and torsion had no effect. This is consistent with the stress effect theory of Li, Oriani, and Darken. The stress effect corresponds to an apparent partial molal volume of 1.7 to 2.2 cm3/mol, depending on the alloy and hydrogen content.

Semilattice decompositions of semigroups

Abstract: The purpose of this paper is to develop a general theory of semilattice decompositions of semigroups from the point of view of obtaining theorems of the type: A semigroup S has propertyD if and only if S is a semilattice of semigroups having property β As such we are able to extend the theories of Clifford [3], Andersen [1], Croisot [5], Tamura and Kimura [14], Petrich [9], Chrislock [2], Tamura and Shafer [15], Iyengar [7] and Weissglass and the author [10] The root of our whole theory is Tamura's semilattice decomposition theorem [12, 13] Of this, we give a new proof

Transvenous coaxial catheter

Abstract: Pacer catheter for an A-V stimulator comprising a catheter assembly which may be passed through a single channel to the heart which assembly will carry both atrial and ventricular stimulation. The catheter provides at least two mutually insulated spatially adjustable electrical conductors, one for stimulating the atrium and an additional one for stimulating the ventricle.

A Scheduling Problem

Abstract: This note treats the optimization problem of minimizing the completion time of jobs in a job-shop with no wait in process. Techniques are presented for restricted cases of the problem.

Effect of route of administration on drug disposition.

Abstract: An increasing body of information tends to support the hypothesis that drug effect, therapeutic or toxic, is more closely correlated with plasma concentration than dose (Levy, 1968). Absorption is one important determinant of drug plasma levels. Distribution and elimination are others. Most drugs are administered as drug products, not drug entities. The biologic performance of a drug product can be affected by its bioavailability (defined as a measure of the rate and extent to which a drug reaches a sampling site (usually a peripheral vein) or its site of action). Biophasic availability is generally reserved for situations where pharmacologic data are used to assess biologic performance (Smolen, 1971). This paper discusses the various factors that can influence the bioavailability of drug products. Major emphasis is placed on preparations intended for oral administration.

Human scalp-recorded evoked-potential correlates of linguistic stimuli

Abstract: Interhemispheric asymmetries for verb and noun meanings of “ambiguous” linguistic stimuli (words) were observed in human scalp recordings of click-evoked brain activity. Linguistic stimuli elicited responses of greater magnitude in the dominant hemisphere. Within-hemisphere response latencies and waveforms were different for verb and noun forms of the stimulus word; whereas between-hemisphere waveforms were similar for a given stimulus word form.

Smoking, Carbon Monoxide, and Coronary Heart Disease

Abstract: M ANY STUDIES have documented a significant association between cigarette smoking and the incidence of myocardial infarction and death from coronary heart disease, independent of other risk factors, especially in young and middleaged men.1-5 Moreover, heavy cigarette smokers have a significantly higher incidence of myocardial infarction and mortality from coronary heart disease than light cigarette smokers. In addition, cigarette smokers who stop smoking have a significantly lower incidence of myocardial infarction and mortality from coronary heart disease than those who continue to smoke. Cigarette smoking has also been correlated with a shorter survival time in patients dying eight hours after the onset of a heart attack.6 Smoking cigarettes also causes patients with angina pectoris due to coronary artery disease to have a significant decrease in exercise performance before the onset of angina.7-9 Smoking highnicotine cigarettes7 aggravates exercise-induced angina more than smoking low-nicotine8 or nonnicotine cigarettes.'0 Smoking low-nicotine cigarettes8 aggravates exercise-induced angina more than smoking nonnicotine cigarettes.'0 Smoking high-nicotine7\" or low-nicotine cigarettes8s 11 causes an increase in systolic blood pressure and in heart rate, consequently increasing the myocardial oxygen demand. This increase in systolic blood pressure and in heart rate does not occur after smoking nonnicotine cigarettes.9-1\" However, smoking high-nicotine, low-nicotine, or nonnicotine cigarettes causes an elevated carboxyhemoglobin level,9 11, 12 which decreases the amount of oxygen available to the myocardium. Therefore, anginal patients develop angina pectoris sooner after exercise following cigarette smoking for at least two reasons: increased myocardial oxygen demand in the presence of nicotine, and decreased oxygen delivery to the myocardium, whether or not nicotine is present.

Preliminary pharmacokinetic studies of propylthiouracil in humans

Abstract: Previous analytical procedures for the analysis of propylthiouracil (PTU) in blood and urine samples are questionable on several points. Therefore, a gas-liquid chromatography method has been developed which is both more sensitive and more specific. Application of this procedure confirmed that the drug was rapidly absorbed and eliminated. The mean terminal half-life in euthyroids was found to be 63 min. One hyperthyroid subject showed a far higher plasma clearance than seen with euthyroids, which requires further study.

Band of t-archimedean semigroups.

Abstract: A semigroup S is called t-archimedean if for all a,b∈S, there exists a positive integer i such that bi∈aS∩Sa. The purpose of this paper is to characterize semigroups which are bands of t-archimedean semigroups. We then apply this result to exponential semigroups.

A study of internal waves in a wind tunnel

Abstract: The combined use of a stratified flow wind tunnel and of periodic sampling methods in low Reynolds number flows allows the recovery of the instantaneous dynamics of internal waves. Several detailed examples are given of the thermal structure of large propagating and breaking internal waves and Kelvin-Hemholtz waves. Preliminary measurements of the stability of finite waves as a function of Richardson number are also reported.