Showing papers by "University of Texas at Austin published in 1978"

The Finite Element Method for Elliptic Problems

Abstract: Preface 1. Elliptic boundary value problems 2. Introduction to the finite element method 3. Conforming finite element methods for second-order problems 4. Other finite element methods for second-order problems 5. Application of the finite element method to some nonlinear problems 6. Finite element methods for the plate problem 7. A mixed finite element method 8. Finite element methods for shells Epilogue Bibliography Glossary of symbols Index.

How safe is safe enough? a psychometric study of attitudes towards technological risks and benefits

Abstract: One of the fundamental questions addressed by risk-benefit analysis is “How safe is safe enough?” Chauncey Starr has proposed that economic data be used to reveal patterns of acceptable risk-benefit tradeoffs. The present study investigates an alternative technique, in which psychometric procedures were used to elicit quantitative judgments of perceived risk, acceptable risk, and perceived benefit for each of 30 activities and technologies. The participants were seventy-six members of the League of Women Voters. The results indicated little systematic relationship between perceived existing risks and benefits of the 30 risk items. Current risk levels were generally viewed as unacceptably high. When current risk levels were adjusted to what would be considered acceptable risk levels, however, risk was found to correlate with benefit. Nine descriptive attributes of risk were also studied. These nine attributes seemed to tap two basic dimensions of risk. These dimensions proved to be effective predictors of the tradeoff between acceptable risk and perceived benefit. The limitations of the present study and the relationship between this technique and Starr's technique are discussed, along with the implications of the findings for policy decisions.

Design and Testing of a Generalized Reduced Gradient Code for Nonlinear Programming

Abstract: : The purpose of this paper is to describe a Generalized Reduced Gradient (GRG) algorithm for nonlinear programming, its implementation as a FORTRAN program for solving small to medium size problems, and some computational results. Our focus is more on the software implementation of the algorithm than on its mathematical properties. This is in line with the premise that robust, efficient, easy to use NLP software must be written and made accessible if nonlinear programming is to progress, both in theory and in practice.

Verbal Art as Performance

Abstract: Departing from text-centered perspectives on verbal art, an approach is developed to verbal art as performance, derived from recent work in folklore, the ethnography of speaking, sociolinguistics, and literary stylistics. The patterning of performance in genres, acts, roles, and events is discussed, as well as the emergent quality of performance, manifested in text, event, and social structure.

The Mussel Watch

Abstract: The levels of four sets of pollutants (heavy-metals, artificial radionuclides, petroleum components, and halogenated hydrocarbons), have been measured in U.S. coastal waters, using bivalves as sentinel organisms. The strategies of carrying out this programme are outlined and the results from the first year's work are given. Varying degrees of pollution in U.S. coastal waters have been indicated by elevated levels of pollutants in the bivalves, which comprised certain species of mussels and oysters and were collected at over one hundred localities.

The culture collevtion of algae at the university of texas ataustin 123

Abstract: TIic Culture Collection of Algac at The University of Texas (Ul EX) at Austin was formerly located at Indiana University, Bloomington. In the summer of 1976 when the writer joined ihc faculty of the Department of Botany at The University of Texas, plans were formtilated for moving ihe Collection. With the cooperatioti of the National Science Foundation atid the Administrations of Indiana University and The University of Texas at Austin, the move was made duritig 1976-77 without atiy interruption of service to the scientific community. The Utiiversiiy of Texas has (lrovided and equipped physical facilities for the maintenance and o{>etation of the Collection. The contitiued support of the Collection as a natiotial researcli resource by the National Science Foundation is gratefully acknowledged. The Fottndation provides ihe tnajor fttiancial supjjon fur the actual oi>eration of the Collection, but funds received frotn the sale of ctiltutes are mainlairivd in a special account for partial support of Collection needs such as postage, supplies, secretarial help» etc.

Events, processes, and states

Abstract: The familiar Vendler-Kenny scheme of verb-types, viz., performances (further differentiated by Vedler into accomplishments and achievements), activities, and states, is too narrow in two important respects. First, it is narrow linguistically. It fails to take into account the phenomenon of verb aspect. The trichotomy is not one of verbs as lexical types but of predications. Second, the trichotomy is narrow ontologically. It is a specification in the context of human agency of the more fundamental, topic-neutral trichotomy, event-process-state. The central component in this ontological trichotomy, event, can be sharply differentiated from its two flanking components by adapting a suggestion by Geoffrey N. Leech and others that the contrast between perfective and imperfective aspect in verbs corresponds to the count/mass distinction in the domain of nouns. With the help of two distinctions, of “cardinal count” adverbials versus frequency adverbials, and of occurrence versus associated occasion, two interrelated criteria for event predication are developed. Accordingly, “Mary capsized the boat” is an event predication because (a) it is equivalent to “There was at least one capsizing of the boat by Mary,” or (b) because it admits cardinal count adverbials, e.g., “at least once,” “twice,” “three times.” Ontologically speaking, events are defined as those occurrences that are inherently countable.

Heterogeneous photocatalytic decomposition of saturated carboxylic acids on titanium dioxide powder. decarboxylative route to alkanes

Abstract: The heterogeneous photocatalytic decomposition of acetic acid/acetate mixtures was studied on n-type TiO/sub 2/ powder. The influence of solution composition, reaction temperature, light intensity, and semiconductor properties (crystallographic structure, doping) was investigated. For photodecarboxylation in the absence of molecular oxygen, anatase powders proved to be most efficient with increased reactivity due to doping and/or partial coverage of the powder particles with platinum. The products of the photodecomposition of acetic acid on platinized anatase powder were mainly methane and CO/sub 2/, with small amounts of hydrogen and ethane. Other saturated carboxylic acids (propionic, n-butyric, n-valeric, pivalic, adamantane-1-carboxylic acid) were also photocatalytically decarboxylated to the corresponding alkanes. An interpretation based on the photoelectrochemical properties of n-type TiO/sub 2/, with photooxidation and (dark) reduction reactions occurring on the particles on local cell processes, is proposed.

New surface-associated heat-labile colonization factor antigen (CFA/II) produced by enterotoxigenic Escherichia coli of serogroups O6 and O8.

Abstract: Enterotoxigenic Escherichia coli (ETEC) belonging to serogroups O6 and O8 do not possess the H-10407-type colonization factor antigen (CFA/I). However, these frequently isolated ETEC were found to possess a second and distinct heat-labile surface-associated colonization factor antigen, termed CFA/II. Whereas CFA/I mediates mannose-resistant hemagglutination of human group A erythrocytes, CFA/II does not. CFA/II mediates mannose-resistant hemagglutination of bovine erythrocytes, and mannose-resistant hemagglutination is rapid only at reduced temperature (4°C). Because CFA/II, like CFA/I, is spontaneously lost by many ETEC isolates in the laboratory, it was possible to produce specific anti-CFA/II serum by preparing antiserum against living cells of a prototype strain (PB-176) and adsorbing this serum with living and heat-treated cells of its CFA/II-negative derivative strain PB-176-P. This serum, which neutralized the colonization factor activity of CFA/II-positive strains in infant rabbits, was employed to confirm the presence of CFA/II on ETEC which exhibited mannose-resistant hemagglutination of bovine but not human erythrocytes. CFA/II, like CFA/I, mediates adherence of the bacteria to the mucosal surface of the small intestine, as demonstrated by indirect immunofluorescence. CFA/II appears to be an important virulence factor for humans since CFA/II-positive ETEC are frequently isolated from diarrhea cases, particularly travelers' diarrhea, in Mexico; these ETEC were not uncommon in a collection of isolates from Bangladesh. The O6:H16 strain of ETEC responsible for an outbreak of diarrhea in the United States was also shown to be CFA/II positive. CFA/I and CFA/II were never found on the same serotypes of ETEC, but 98% of the heat-stable and heat-labile enterotoxin-producing ETEC belonging to the frequently isolated serogroups O6, O8, O15, O25, O63, and O78 were positive for either CFA/I or CFA/II.

Computation and transmission requirements for a decentralized linear-quadratic-Gaussian control problem

Abstract: A decentralized control problem involving K nodes is formulated At each node are sensors and controls. The object is to share the information of each sensor, processed with a local Kalman estimator, with all the other nodes so that the controllers can be computed using the best estimate of the state of the system given the information from all the sensors. The controls are determined so that the expected value of a quadratic performance index is minimized. The problem is formulated as a decentralized control problem without a central supervisor so that the system performance will degrade gracefully under structural perturbations. Therefore, the transmission of data is from each node to every other node; there are \sum\liminf{i-1}\limsup{k}(i-1) links connecting all nodes. It is shown that if the dimension of the controls at each node l is less than both the dimension of the data at node m and the dimension of the state, then a data vector with dimension of the control at l can be transmitted from m to l . compression of data transmission is done at the expense of propagating an additionaal data dependent vector at each node beyond the usual Kalman filter equations.

The “Past” and the “Delayed-Choice” Double-Slit Experiment

Abstract: Publisher Summary Partway down the optic axis of the traditional double­slit experiment stands the central element, the doubly-slit screen This chapter discusses the question whether the photon—or the electron—shall have come through both the slits or only through one of them after it has already transversed that screen The possibility to use the receptor at the end of the apparatus to record well-defined interference fringes is known One can determine the lateral kick given to the receptor by each arriving quantum and can record the fringes or the kicks but not both The arrangement for the recording of the one automatically rules out the recording of the other It is easy to complicate the double-slit interference pattern For that purpose, it is enough to have a complicated single-slit diffraction pattern and let the waves from two such slits interfere It is not necessary to understand every point about the quantum principle in order to understand something about it

Heterogeneous photocatalytic synthesis of methane from acetic acid: new Kolbe reaction pathway

Abstract: The heterogeneous photocatalytic decomposition of acetic acid on n-type TiO/sub 2/ to yield almost exclusively methane and carbon dioxide is reported. Probable reaction mechanisms are discussed. It is assumed that the TiO/sub 2/ powder acts in a dual function causing the photooxidation of acetate and the reduction of intermediately formed methyl radicals. This property is not found at metal electrodes under usual Kolbe conditions. (JSR)

Thermal continuum from accretion disks in quasars

Abstract: It is argued that supermassive accretion in disks may explain the flat optical continuum observed from some QSOs and Seyfert galaxies. With the aid of energy considerations it is shown that a luminous QSO may be powered by accretion onto a black hole with a mass corresponding to that of 100 million solar masses. It is proposed that the blue continuum component of 3C 273 is thermal continuum emission from the inner part of an accretion disk that powers 3C 273. The present model suggests that many QSOs and Seyfert galaxies may show a power law continuum plus thermal emission from the disk at optical or UV frequencies. Many such objects show indeed a flattening or upturn of their continua in the blue. The QSO PHL 957 shows a flat continuum and indications of a cutoff at the highest observed frequencies.

Open reduction of carpal dislocations: indications and operative techniques.

Abstract: Based on their personal experience with 49 carpal dislocations in 46 patients, the authors suggest the following in the management of the acute injury: (1) Dorsal trans-scaphoid perilunate dislocation. After closed reduction, if the scaphoid is not anatomically reduced, primary open reduction and internal fixation with Kirschner wires is advised. A volar (Russe-type) approach gives adequate exposure, and bone grafting probably is not necessary. Satisfactory results can be achieved if the operation is done anytime within 2 weeks of injury. (2) Dorsal perilunate and volar lunate dislocation. Since cineradiographic studies show clearly that the lunate dislocation is usually the end stage of a perilunate dislocation, these injuries are treated identically after the initial closed reduction. Indications for open reduction are rotary subluxation of the scaphoid or lunate instability (dorsiflexion instability or volar subluxation). A dorsal approach is adequate for scaphoid subluxation alone, but combined dorsal plus volar approaches should be used for volar subluxation of the lunate with rotary subluxation of the scaphoid. Best results are achieved with open reduction as soon after the injury as possible. Factors in this series which were associated with poorer results were volar dislocation of the proximal pole of the scaphoid with the lunate, severely comminuted radial styloid fractures, extensive osteochondral fractures of the carpal bones, and late open reduction of rotary scaphoid subluxation.

Geographical Trends in Numbers of Species

Abstract: Geographic variation in the number of coexisting plant and animal species (species density) often follows repeated patterns; best known is the general increase in species richness from temperate to tropical latitudes. Here we undertake a quantitative analysis of geographic trends in species density for the terrestrial vertebrate faunas of the United States and Australia. Trends in numbers of species of amphibians, reptiles, birds, and mammals are described and are correlated with geographic variation in abiotic environmental measures. Intercontinental comparisons reveal general patterns as well as intriguing and profound differences in vertebrate distributions.

Innovation Diffusion in a Dynamic Potential Adopter Population

Abstract: Existing single-adoption diffusion models assume a static constant ceiling on the number of adopters, that is, a constant population of potential adopters, over the entire time frame of the diffusion process. However, for most innovations this assumption is tenuous. Rather, the ceiling, or the potential adopter population is more likely to be dynamic. The present paper relaxes this assumption and presents a dynamic diffusion model. To illustrate the application of this model, data from two innovations are analyzed.

Physical Illness Presenting as Psychiatric Disease

Abstract: • A study of 658 consecutive psychiatric outpatients receiving careful medical and biochemical evaluation, defined an incidence of medical disorders productive of psychiatric symptoms in 9.1% of cases. The most frequent presentations were of depression, confusion, anxiety, and speech or memory disorders. The presence of visual hallucinations was believed to indicate medical etiology until proved otherwise. Major illnesses presenting with psychiatric symptoms in order of frequency were infectious, pulmonary, thyroid, diabetic, hematopoietic, hepatic and CNS diseases. Forty-six percent of these patients suffered from medical illnesses previously unknown to either them or their physician. A plea is made for careful medical evaluation of psychiatric patients.

Plant chemistry and the evolution of host specificity: new evidence from heliconius and passiflora.

Abstract: Larval growth rates of Heliconius butterflies do not closely parallel host plant choice, an indication that factors other than host plant chemistry are important in evolving host specificity. High growth rate in one species is correlated with reduction in number of palatable host species. This suggests a mechanism by which ecologically restricted species become progressively biochemically specialized.

The abundances of the elements in the solar photosphere – VIII. Revised abundances of carbon, nitrogen and oxygen

Abstract: All accessible atomic and molecular signatures of carbon, nitrogen and oxygen are integrated in this comprehensive updating of an earlier paper in this series (Lambert 1968). The reasons for presenting another CNO abundance study are stated briefly in this Introduction. External interest in accurate CNO abundances remains high: the solar abundances are a primary source for the entry in cosmic abundance tables (cf. Cameron 1973); depletion of these elements in the interstellar gas is measured with reference to the solar abundance in the absence of reliable abundances from younger objects (OB stars, H 11 regions); accurate photospheric abundances are required for an assessment of interesting diffusion effects in the corona and solar wind for wh ich accurate abundances are becoming available. Significant progress on the thorny problem of fvalues for atomic and molecular lines has been reported in recent years. Highlights include exciting new experimental results on forbidden lines, the application of pulsed dye lasers and the introduction of the high-frequency deflection technique for the precise measurement of radiative lifetimes for individual rotational states. Although the progress since the 1968 paper has been dramatic, lacunae exist and a subsidiary purpose of thispaper is to spotlight the critical gaps. Little attention in recent years appears to have been directed at the N and 0 abundances. The C abundance has been the focus of several new analyses. In recent papers (Mount & Unsky 1975a and references therein), a suggestion is promoted that the C abundance should be reduced by about 0.2 dex from the 1968 value. The present discussion of the prime abundance sources shows that this correction factor is incorrect; the new abundance is 0.12 dex higher than in 1968.