Showing papers by "University of Texas at Austin published in 1989"
TL;DR: In this article, five different approaches to the cosmological constant problem are described, and a brief review of the history of this problem is given. But none of the approaches are considered in this paper.
Abstract: Astronomical observations indicate that the cosmological constant is many orders of magnitude smaller than estimated in modern theories of elementary particles. After a brief review of the history of this problem, five different approaches to its solution are described.
6,248 citations
TL;DR: In this paper, voltammetric methods were used to probe the interaction (electrostatic or intercalative) of metal complexes, ML 3 3+/2+, with calf thymus DNA.
Abstract: Voltammetric methods were used to probe the interaction (electrostatic or intercalative) of metal complexes, ML 3 3+/2+ , with calf thymus DNA. Binding constants (K n+ ) and binding site sizes (s) were determined from voltammetric data. The exact magnitude for the parameters depends on whether the ML 3 3+/2+ /DNA reaction is assumed to be static (S) or mobile (M) within the characteristic time of a voltammetric experiment
1,567 citations
Book•
01 Jan 1989TL;DR: In this article, a study of electoral systems which describes the electoral rules of different nations, reviews the state of knowledge about their effects and offers guidelines for designing new systems is presented.
Abstract: A study of electoral systems which describes the electoral rules of different nations, reviews the state of knowledge about their effects and offers guidelines for designing new systems.
1,202 citations
TL;DR: A review of previous research yields four key issues that form the core of a theory of hybrid arrangements as mentioned in this paper, which is then used to generate researchable propositions that explore differences among types of hybrids and to offer insights for managers of hybrid organizations.
Abstract: Hybrid organizational arrangements, in which two or more sovereign organizations combine to pursue common interests, raise significant questions for both scholars and managers. A review of previous research yields four key issues—breadth of purpose, boundary determination, value creation, and stability mechanisms—that form the core of a theory of hybrid arrangements. This theory is then used to generate researchable propositions that explore differences among types of hybrids and to offer insights for managers of hybrid organizations.
1,135 citations
TL;DR: The personality traits in the right column and tick the traits that describe you are: Dependable, well-organized, responsible, conscientious, self-confident, honest, and self-control as mentioned in this paper.
Abstract: 2. Please take a look at the personality traits in the right column and tick the traits that describe you. □ Dependable □ Well-organized □ Responsible □ Good selfcontrol □ High achiever □ Cautious □ Spoilt □ Objective □ Demanding □ Conscientious □ Independent □ Self-confident □ Reliable □ High achiever □ Serious □ Supporter of law and order □ Humorous □ A perfectionist □ Patient □ Disorganized □ Introvert □ Dependent □ Diligent □ Irresponsible □ Spoilt □ Impatient □ Uncomplicated □ Outgoing □ Creative □ A negotiator □ Shy and quiet □ Calm □ Even-tempered □ Competitive □ Easygoing □ Friendly □ A peace-maker □ A people-pleaser □ A great listener □ Responsible □ Bossy □ Intimidating □ Competent □ Studious □ Extrovert □ Messy □ Amiable □ Picky 3. Are there any other personality traits you have but cannot find on the list above? Please write them in the right column.
1,084 citations
TL;DR: An efficient probabilistic set covering heuristic is presented that provides the best known solutions to all other instances attempted to solve set covering problems that arise from Steiner triple systems.
1,038 citations
TL;DR: In this article, the authors investigated senior management turnover in financially distressed firms and found that 52% of managers experience turnover if their firms are either in default on their debt, bankrupt, or privately restructuring their debt to avoid bankruptcy.
1,026 citations
TL;DR: In this article, the R→0 limit of toroidal compactification in various string theories is considered and connections between seemingly different string theories: IIA and IIB, open and closed, oriented and unoriented.
Abstract: We consider the R→0 limit of toroidal compactification in various string theories. This leads to new connections between seemingly different string theories: IIA and IIB, open and closed, oriented and unoriented. We also find two new extended objects which can couple consistently to strings: the Dirichlet-brane and the orientifold plane.
993 citations
TL;DR: In this article, a σ-model calculation in the mixed Dirichlet-Neumann theory was performed and it was shown that the action of the Dirac-Born-Infeld type is restricted to (26−k)-dimensions.
Abstract: In a recent paper we discussed, among other things, the effect of duality transformations on the open bosonic string theory. Namely, we conjectured that a macroscopic object, the D-brane, effectively interacts with closed and open string modes in the low energy limit. This conjecture was supported by a string scattering amplitude calculation. In this letter we report on a σ-model calculation in the mixed Dirichlet-Neumann theory. We find an action of the Dirac-Born-Infeld type restricted to (26−k)-dimensions.
983 citations
TL;DR: In this paper, different modes of operation for the SECM are discussed, including collectlon modes, where products electrogenerated at the substrate are detected at the tip (held at constant potentlal or operated In the cyclic voltammetrlc mode), and feedback modes where the effect of substrate on the tlp current is monltored.
Abstract: The technlque of scannlng electrochemical mlcroscopy (SECM) Is descrlbed. In thls technlque the electrolysls current that flows as an ultramicroelectrode tlp (diameter ca. 10 gm) Immersed In a soiutlon Is moved above a substrate surface is used to characterize processes and structural features of the substrate. Modes of Operation consldered Include collectlon modes, where products electrogenerated at the substrate are detected at the tip (held at constant potentlal or operated In the cyclic voltammetrlc mode), and feedback modes, where the effect of substrate on the tlp current Is monltored. The feedback mode can be used with both conductive and lnsulatlng substrates and Is less sensithe to electrlcal coupllng between substrate and tlp. An ailernatlng current generatlon/collectlon mode Is also described. Experimental results for the different modes of Operation and proposed extensions of the SECM technlque are presented.
965 citations
TL;DR: Three factors were identified that uniquely contribute to people's global self-esteem: people's tendencies to experience positive and negative affective states, people's specific self-views (i.e., their conceptions of their strengths and weaknesses), and the way people frame their self- views.
Abstract: Three factors were identified that uniquely contribute to people's global self-esteem: (a) people's tendencies to experience positive and negative affective states, (b) people's specific self-views (i.e., their conceptions of their strengths and weaknesses), and (c) the way people frame their self-views. Framing factors included the relative certainty and importance of people's positive versus negative self-views and the discrepancy between people's actual and ideal self-views. The contribution of importance to people's self-esteem, however, was qualified in 2 ways. First, importance contributed only to the self-esteem of those who perceived that they had relatively few talents. Second, individuals who saw their positive self-views as important were especially likely to be high in self-esteem when they were also highly certain of these positive self-views. The theoretical and therapeutic implications of these findings are discussed.
Book•
18 Dec 1989TL;DR: This text gives a self-contained foundation of predicate transformer semantics by making extensive use of the predicate calculus and shows how to cope unbounded nondeterminacy without using transfinite induction.
Abstract: This text gives a self-contained foundation of predicate transformer semantics by making extensive use of the predicate calculus The semantics of the repetitive construct is defined in terms of weakest and strongest solutions in terms of the weakest precondition and the weakest liberal precondition, the notion of determinacy is defined it is shown how to cope unbounded nondeterminacy without using transfinite induction
TL;DR: In this article, the authors developed quantitative-genetic models for the evolution of multiple traits under maternal inheritance, in which traits are transmitted through non-Mendelian as well as Mendelian mechanisms, and maternal selection, where the fitness of offspring depends on their mother's phenotype and their own.
Abstract: We develop quantitative-genetic models for the evolution of multiple traits under maternal inheritance, in which traits are transmitted through non-Mendelian as well as Mendelian mechanisms, and maternal selection, in which the fitness of offspring depends on their mother's phenotype as well as their own. Maternal inheritance results in time lags in the evolutionary response to selection. These cause a population to evolve for an indefinite number of generations after selection ceases and make the rate and direction of evolution change even when the strength of selection and parameters of inheritance remain constant. The rate and direction of evolution depend on the inheritance of traits that are not under selection, unlike under classical Mendelian inheritance. The models confirm earlier findings that the response to selection can be larger or smaller than what is possible with simple Mendelian inheritance, and even in a direction opposite to what selection favors. Maternal selection, in which a mother's phenotype influences her offspring's fitness, is frequency-dependent and can cause a population to evolve maladaptively away from a fitness peak, regardless of whether traits are transmitted by Mendelian or maternal inheritance. Maternal selection differs from other forms of selection in that its force depends not only on the fitness function but also on the phenotypic resemblance of parents and offspring.
TL;DR: This paper provides all the details necessary for implementation of a Monte Carlo program andVariance reduction schemes that improve the effiency of the Monte Carlo method are discussed.
Abstract: The Monte Carlo method is rapidly becoming the model of choice for simulating light transport in tissue. This paper provides all the details necessary for implementation of a Monte Carlo program. Variance reduction schemes that improve the eciency of the Monte Carlo method are discussed. Analytic expressions facilitating convolution calculations for finite flat and Gaussian beams are included. Useful validation benchmarks are presented.
TL;DR: It is suggested that severe, prolonged cellular injury induces a preneoplastic proliferative response that fosters secondary genetic events that program the cell for unrestrained growth.
01 Jan 1989
TL;DR: My goal is to propose a set of questions that I think are important and to work on these questions with J. J. Misra, a researcher at the University of California, Berkeley.
Abstract: My goal is to propose a set of questions that I think are important. J. Misra and I are working on these questions.
TL;DR: The three reproductive patterns are interpreted as being adaptative with respect to relative intensity and predictability of temporal and spatial variation in abiotic environmental parameters, food availability, and predation pressure.
Abstract: Ten traits related to life history theory were measured or estimated for 71 freshwater fish species from two locations in the Venezuelan llanos. Multivariate statistics and cluster analysis revealed three basic endpoint patterns bounding a two-dimensional continuum. A suite of attributes associated with parental care and aseasonal reproduction appeared to correspond to an equilibrium strategy. A second group of small fishes was distinguished by traits associated with rapid colonizing ability: early maturation, continuous reproduction, and small clutches. The third basic pattern was associated with synchronized reproduction during the early wet season, high fecundity, absence of parental care, and breeding migrations. A subset of mostly small fishes exhibiting little or no parental care, small clutches, and two to four month reproductive seasons was intermediate between the opportunistic (rapidly colonizing) and seasonal strategies. All ten life history variables showed significant effects of phylogeny. The cluster of species corresponding to the equilibrium group was dominated by siluriform fishes and perciforms of the Cichlidae. The opportunistic cluster was dominated by cyprinodontiform and characiform fishes, whereas the seasonal cluster contained primarily characiform and siluriform fishes. Seven of nine traits were significantly correlated with body length. The three reproductive patterns are interpreted as being adaptative with respect to relative intensity and predictability of temporal and spatial variation in abiotic environmental parameters, food availability, and predation pressure.
TL;DR: A new type of cosmological history which includes large-scale entropy production is proposed in this paper, which is based on a reinterpretation of the matter-energy stress tensor in Einstein's equations.
Abstract: A new type of cosmological history which includes large-scale entropy production is proposed These cosmologies are based on a reinterpretation of the matter-energy stress tensor in Einstein's equations This modifies the usual adiabatic energy conservation laws, thereby leading to a possible irreversible matter creation This creation corresponds to an irreversible energy flow from the gravitational field to the created matter constituents This new point of view results from the consideration of thermodynamics of open systems in the framework of cosmology It appears that the usual initial singularity is structurally unstable with respect to irreversible matter creation The corresponding cosmological history therefore starts from an instability of the vacuum rather than from a singularity The universe evolves through an inflationary phase This appears to be an attractor independent of the initial vacuum fluctuation
TL;DR: The authors found that closeness has an effect at both the mass and elite levels of an election, and they also provided quantitative estimates of the effect of Senate and gubernatorial expenditure on House turnout.
Abstract: Students of elections have repeatedly found that the closeness of an election is modestly correlated with turnout. This may be due to a direct response of instrumentally motivated voters, but recent theoretical work casts doubt on the adequacy of this explanation. Another possibility is that elite actors respond to closeness with greater effort at mobilization. We explore the latter possibility by using FEC and state data on campaign expenditures in House, Senate, and gubernatorial races. Our results indicate that closeness has an effect at both the mass and elite levels. We also provide quantitative estimates of the effect of Senate and gubernatorial expenditure on House turnout.
TL;DR: In this paper, the steady-state current that flows between a disk ultramicroelectrode imbedded in an insulating sheath and a planar sample substrate in a scannlng electrochemical microscope (SECM) operating in the feedback mode is calculated by the finite element method with an exponentlaily expandlng grld, for both conductlve and insulating samples.
Abstract: The steady-state current that flows between the scanning tlp (a disk ultramicroelectrode imbedded in an Insulating sheath) and a planar sample substrate in a scannlng electrochemical microscope (SECM) operating in the feedback mode is calculated by the finite element method with an exponentlaily expandlng grld, for both conductlve and Insulating samples. For conductlve substrates the tip current, representing, for example, the oxidatkn reactlon of R to 0, is enhanced by flow of R generated at the substrate to the tlp and is a functlon of tiphubstrate distance, d, but not the radius of the lnsuiatlng sheath. For insulating substrates, the tlp current Is decreased by blockage of the diffusion of R to the tip by the substrate and depends upon d and the Insulating sheath radius. The theoretical results are compared to experimental studies.
TL;DR: The authors analyzes economic characteristics of firms that correct previously reported quarterly earnings and finds that the sample (correcting) firms are smaller, less profitable, have higher debt, slower growing, and face more serious uncertainties.
TL;DR: A simple alternative representation of density fluctuations is given that is both fully covariant and gauge invariant; thus it sidesteps the usual problems and is standard, but its derivation is completely transparent.
Abstract: It has been known for a long time that the gauge problem plagues the study of density perturbations in cosmology. The quantity {delta}{mu}/{mu} (the fractional variation in density along a world line) usually determined in perturbation calculations is completely dependent on the gauge chosen. Even the fully covariant approach of Hawking (1966) is not immune. Bardeen's major paper (1980) determines a set of gauge-invariant quantities that are related to density perturbations but are not those perturbations themselves. We give a simple alternative representation of density fluctuations. This representation is both fully covariant and gauge invariant; thus it sidesteps the usual problems. The basic quantity used to represent density inhomogeneities is the {ital comoving} {ital fractional} {ital gradient} {ital of} {ital the} {ital energy} {ital density orthogonal} {ital to} {ital the} {ital fluid} {ital flow}. Our description does not make the usual assumption that this gradient is small. Exact (fully nonlinear) propagation equations are derived for this quantity. They are then linearized to give propagation equations appropriate to the case of an almost-Robertson-Walker universe. Their solutions are obtained in a simple case which can be compared with the standard theory; we recover the usual growing and decaying modes. Thus the resultmore » is standard, but its derivation is completely transparent. We give an interpretation of the Bardeen variables in terms of our formalism.« less
TL;DR: In this article, the dynamics of the standard gravitational action without a cosmological constant were analyzed from the point of view of constrained hamiltonian systems, and it was observed that contrary to what one might think, the theory is fully covariant and contains only one overall degree of freedom (the cosmologically constant) in addition to the two degrees of freedom per point of ordinary Einstein's theory.
TL;DR: In this paper, un modele important du point de vue thermodynamique est developpe pour representer les equilibres liquide vapeur dans des systemes ternaires constitues d'un gaz acide, H 2 S ou CO 2, d'alcanolamine, monoethanolamine ou diethanolamine and d'eau.
Abstract: Un modele important du point de vue thermodynamique est developpe pour representer les equilibres liquide vapeur dans des systemes ternaires constitues d'un gaz acide, H 2 S ou CO 2 , d'un alcanolamine, monoethanolamine ou diethanolamine et d'eau
TL;DR: In this article, a general framework for introducing nonlinear corrections into ordinary quantum mechanics, that can serve as a guide to experiments that would be sensitive to such corrections, is presented, including the precession of spinning particles in external fields, experiments of Stern-Gerlach type, and the broadening and de-tuning of absorption lines.
TL;DR: A cone ratio data envelopment analysis (DEA) model that substantially generalizes the Charnes-Cooper-Rhodes (CCR) model and characterizes its efficiency classes is developed and studied as discussed by the authors.
Abstract: A new ‘cone ratio’ data envelopment analysis (DEA) model that substantially generalizes the Charnes-Cooper-Rhodes (CCR) model and the Charnes-Cooper-Thrall approach characterizing its efficiency classes is developed and studied. It allows for infinitely many decision-making units (DM Us) and arbitrary closed convex cones for the virtual multipliers as well as the cone of positivily of the vectors involved. Generalizations of linear programming and polar cone equalizations arc the analytical vehicles employed.
TL;DR: The authors reviewed the structure and content of the 83 parent attitude questionnaires published from 1899 through 1986 designed to quantify variations in parental attitudes and, presumably, parental behavior and found that one suspected source of problems with the instruments, the use of vague and ambiguous items, was confirmed in a study of mothers' reactions to one survey.
Abstract: Describes historical use of surveys to assess parents' global child-rearing attitudes and reviews the structure and content of the 83 parent attitude questionnaires published from 1899 through 1986 designed to quantify variations in parental attitudes and, presumably, parental behavior. Inspection of the surveys' psychometric properties reveals marginally acceptable levels of reliability and questionable validity. One suspected source of problems with the instruments, the use of vague and ambiguous items, was confirmed in a study of mothers' reactions to one survey. In addition to instrument errors, conceptual problems associated with assumptions about the structure of parental attitudes and how attitudes relate to parental behavior are discussed. Alternative methods for assessing parental social cognitions and individual differences in parents are advocated. One of the oldest and most important questions in psychology concerns the role the environment plays in the development of an individual. At least in the opening scenes of ontogeny, parents are generally recognized to be the protagonists and the family to be the "primary arena" for socialization (Maccoby, 1984). Parents have frequently been implicated as principal causal agents in their children's behavioral, emotional, personality, and cognitive development. This influence is achieved through a variety of active and passive, reactive and nonreactive processes (Baumrind, 1980; Radke-Yarrow & Zahn-Waxler, 1986; Scarr
TL;DR: The authors found that people with low self-esteem as well as those with high selfesteem preferred feedback pertaining to their positive rather than negative self-views, regardless of their level of global selfesteem.
Abstract: Three studies asked why people sometimes seek positive feedback (self-enhance) and sometimes seek subjectively accurate feedback (self-verify). Consistent with self-enhancement theory, people with low self-esteem as well as those with high self-esteem indicated that they preferred feedback pertaining to their positive rather than negative self-views. Consistent with self-verification theory, the very people who sought favorable feedback pertaining to their positive self-conceptions sought unfavorable feedback pertaining to their negative self-views, regardless of their level of global self-esteem. Apparently, although all people prefer to seek feedback regarding their positive self-views, when they seek feedback regarding their negative self-views, they seek unfavorable feedback. Whether people self-enhance or self-verify thus seems to be determined by the positivity of the relevant self-conceptions rather than their level of self-esteem or the type of person they are.
TL;DR: The mechanisms for production of backscatter contrast, as well as attenuation contrast and speed of sound contrast, and the potential advantages and disadvantages of various classes of contrast agents are explained.
Abstract: We review the field of contrast agents in diagnostic ultrasound. The progress in the development of various classes of contrast agents such as free and encapsulated gas bubbles, colloidal suspensions, emulsions, and aqueous solutions is described. The mechanisms for production of backscatter contrast, as well as attenuation contrast and speed of sound contrast are explained. Finally, the potential advantages and disadvantages of various classes of contrast agents are compared.