Showing papers by "University of Maryland, College Park published in 1978"
TL;DR: In this paper, the effect of good mood on cognitive processes was investigated in a shopping mall environment, where a positive feeling state was induced by giving subjects a free gift, and good mood, thus induced, was found to improve subjects' evaluations of the performance and service records of products they owned.
Abstract: Two studies investigated the effect of good mood on cognitive processes. In the first study, conducted in a shopping mall, a positive feeling state was induced by giving subjects a free gift, and good mood, thus induced, was found to improve subjects' evaluations of the performance and service records of products they owned. In the second study, in which affect was induced by having subjects win or lose a computer game in a laboratory setting, subjects who had won the game were found to be better able to recall positive material in memory. The results of the two studies are discussed in terms of the effect that feelings have on accessibility of cognitions. In addition, the nature of affect and the relationship between good mood and behavior (such as helping) are discussed in terms of this proposed cognitive process.
1,256 citations
TL;DR: In this article, a-posteriori error estimates for finite element solutions are derived in an asymptotic form for h 0 where h measures the size of the elements.
Abstract: Computable a-posteriori error estimates for finite element solutions are derived in an asymptotic form for h 0 where h measures the size of the elements. The approach has similarity to the residual method but differs from it in the use of norms of negative Sobolev spaces corresponding to the given bilinear (energy) form. For clarity the presentation is restricted to one-dimensional model problems. More specifically, the source, eigenvalue, and parabolic problems are considered involving a linear, self-adjoint operator of the second order. Generalizations to more general one-dimensional problems are straightforward, and the results also extend to higher space dimensions; but this involves some additional considerations. The estimates can be used for a practical a-posteriori assessment of the accuracy of a computed finite element solution, and they provide a basis for the design of adaptive finite element solvers.
1,211 citations
TL;DR: This paper presents a review of a variety of techniques for automatic threshold selection, including global, local, and dynamic methods, which have been proposed for automatic thresholds selection in image segmentation.
565 citations
TL;DR: Theoretical models and epidemiologic data showed that the prevalence of gonorrhea adjusts rapidly to changes in social behavior, medical treatment, and control programs, and prevalence oscillates seasonally around an equilibrium state determined by the current social and medical conditions.
Abstract: Calculations revealed that approximately a third of the reported cases of gonorrhea in women during 1973-1975 were discoveries of the screening program. Theoretical models and epidemiologic data showed that the prevalence of gonorrhea adjusts rapidly to changes in social behavior, medical treatment, and control programs, that prevalence oscillates seasonally around an equilibrium state determined by the current social and medical conditions, and that this equilibrium moves as epidemiologic conditions change. The incidence of gonorrhea is theoretically limited by saturation in a sexually active core population, and this core causes gonorrhea to remain endemic.
404 citations
TL;DR: The relationship of social class to self-esteem is riddled with contradictions, showing positive, null, and inverse relationships as mentioned in this paper, and four principles of selfesteem development are advanced to account for these conditional relations-social comparison processes, reflected appraisals, selfperception theory, and psychological centrality.
Abstract: The literature on the relationship of social class to self-esteem is riddled with contradictions, showing positive, null, and inverse relationships. Two studies examinig this relationship are compared-one, a sample of children aged 8-18; the other, a sample of adults aged 18-65. The results indicate virtually no association for younger children, a modest association for adolescents, and a moderate association for adults. Four principles of self-esteem development are advanced to account for these conditional relations-social comparison processes, reflected appraisals, self-perception theory, and psychological centrality. It is suggested that these principles apply equally to adults and children and that the identical principles help to explain why social class should have different effects on the self-esteem of children and adults.
397 citations
01 Jul 1978
TL;DR: This paper reviews various channel models, noting the interaction between channel modeling and error control.
Abstract: Errors encountered in digital transmission over most real communication channels are not independent but appear in clusters. Such channels are said to exhibit memory, i.e., statistical dependence in the occurrence of errors; and thus cannot be adequately represented by the classical memoryless binary symmetric channel. The existence of memory implies additional capacity. To exploit this through efficient coding schemes, it is necessary to describe and model the underlying statistical structure of the error process. This paper reviews various channel models, noting the interaction between channel modeling and error control.
391 citations
TL;DR: This compilation shows that plant oils are excellent sources of phytosterols, and Nuts and seeds contain moderate levels, and fruits and vegetables generally contain the lowest concentrations of plant sterols.
Abstract: Available data on phytosterols from the world's literature have been compiled and summarized. There still exists a paucity of data on the quantities of plant sterols in many foods. More extensive data are available on the relative sterol composition. Our compilation shows that plant oils are excellent sources of phytosterols. Nuts and seeds contain moderate levels, and fruits and vegetables generally contain the lowest concentrations of plant sterols. Analyses of the minor sterols, namely, the delta5- and delta7-phytosterols, have become available only recently.
326 citations
316 citations
TL;DR: This paper discusses a method of point pattern matching that can define a figure of merit for δij according to how closely other point pairs coincide underδij, and its possible advantages relative to other methods are discussed.
310 citations
TL;DR: In this paper, a class of piecewise continuous, piecewise C1 transformations on the interval J c R with finitely many discontinuities n are shown to have at most n invariant measures.
Abstract: A class of piecewise continuous, piecewise C1 transformations on the interval J c R with finitely many discontinuities n are shown to have at most n invariant measures. 1. The way phenomena or processes evolve or change in time is often described by differential equations or difference equations. One of the sim- plest mathematical situations occurs when the phenomenon can be described by a single number and when this number can be estimated purely as a function of the previous number. That is, when the number xn+x can be written as xn+x = t(x") where t maps an interval J c R into itself. For x E J, let t°(x) denote x and t"+x(x) denote t(t"(x)) for n = 0,1.We will sayp E J is a periodic point with period n if p = t"(p) andp ¥= rk(p) for 1 1. In this paper we assume t is piecewise continuous and piecewise twice continuous differentiable. We also assume that a t ^ > 1 where Jx — j x E /, — t(x) exists \.
266 citations
TL;DR: The authors presented estimates for both the United States and the United Kingdom based on data gathered at the firm level, using procedures derived to meet these objections, and obtains estimates significantly greater than those of previous studies.
Abstract: In 1954, Arnold Harberger estimated the welfare losses from monopoly for the United States at o.i of 1% of GNP. Several studies have appeared since, reconfirming Harberger's early low estimates using different assumptions. The present paper levels several objections against the Harberger-type approach. It then calculates estimates of the welfare loss from monopoly using procedures derived to meet these objections, and obtains estimates significantly greater than those of previous studies. Although several of the objections we make have been made by other writers, none has systematically adjusted the basic Harberger technique to take them into account. Thus all previous estimates of monopoly welfare losses suffer in varying degrees from the same biases incorporated in Harberger's original estimates. We present estimates for both the United States and the United Kingdom based on data gathered at the firm level. [Авторский текст]
TL;DR: There is supporting and some contrary evidence from the literature for the generality of the hypothesis that those taxa or growth stages which are large, and thus subject to intense predation relative to smaller forms, should be most strongly constrained to nocturnal drift activity.
Abstract: Nocturnal drift of stream invertebrates is examined as a predator avoidance adaptation via the hypothesis that those taxa or growth stages which are large, and thus subject to intense predation relative to smaller forms, should be most strongly constrained to nocturnal drift activity. Smaller taxa or stages may be aperiodic or day active. Data from an alpine stream document for the abundant and widespread mayfly Baetis bicaudatus that, on a continuum from small to large size, the risk of predation increases while the propensity to drift during the day decreases. There is supporting and some contrary evidence from the literature for the generality of this pattern.
TL;DR: An adaptive quantization scheme, based on histogram peak sharpening, was applied to two of the images; the results do not seem to be as good as those obtained using variable thresholding.
TL;DR: Kerley's original data have been re-analyzed to produce new regression equations and to document the original field size.
Abstract: Problems recently discovered in the Kerley method of estimating age at death from cortical microstructure are discussed. Kerley's original data have been re-analyzed to produce new regression equations and to document the original field size.
TL;DR: Gastropod adaptations conferring resistance to crushing by crabs include a thick shell, narrow or otherwise small aperture, thickened outer lip, strong sculpture, and a low spire, which lowers the critical size of the prey, which permits escape from cushing at a smaller size.
TL;DR: It is found that the families of schizophrenics contend with formidable emotional burdens and recommended that social supports and services be created to help minimize their distress.
Abstract: Although many professionals have explored the effect of chronic physical illness on families, less attention has been paid to what happens to a family when one of its members is mentally ill. The study described here found that the families of schizophrenics contend with formidable emotional burdens and recommended that social supports and services be created to help minimize their distress.
TL;DR: In this paper, a multivariable Fokker-planck equation (FPE) is used to investigate the equilibrium and dynamical properties of a nonlinear stochastic model.
Abstract: A multivariable Fokker-Planck equation (FPE) is used to investigate the equilibrium and dynamical properties of a nonlinear stochastic model. The model displays a phase transition. The equilibrium distributions are found to be non-Gaussian; the deviation from Gaussian is especially significant near the transition point. To study the nonequilibrium behavior of the model, a self-consistent dynamic mean field (SCDMF) theory is derived and used to transform the FPE to a systematic hierarchy of equations for the cumulant moments of the time-dependent distribution function. These equations are numerically solved for a variety of initial conditions. During the time evolution of the system from an initial unstable equilibrium state to the final equilibrium state, three distinct time stages are found.
TL;DR: Analysis of a nationwide study of tenth-grade boys shows that self-esteem is the more powerful causal factor, even when initial levels of delinquency are held constant, and this result is found to be stronger in the lower class than in the upper class.
Abstract: Cross-lagged panel correlation technique is used to examine whether self-esteem has a greater effect on delinquency than delinquency has on self-esteem Analysis of a nationwide study of tenth-grade boys shows that self-esteem is the more powerful causal factor, even when initial levels of delinquency are held constant This result, however, is found to be stronger in the lower class than in the upper class These data are interpreted as lending greater support to Kaplan's theory of the self-enhancing nature of delinquent behavior than to the idea of reflected appraisals
TL;DR: In this paper, the PIMS approach was found to be the best current attempt to gather and analyze data on strategic actions of businesses and suggested improvements will enhance its usefulness to the practitioner.
Abstract: The PIMS research program is examined in eight key areas. In general, the PIMS approach was found to be the best current attempt to gather and analyze data on strategic actions of businesses. Suggested improvements will enhance its usefulness to the practitioner. These improvements will further the state of theoretical model building and validation in the strategy field.
TL;DR: In this article, air filter samples were collected at four sites in Washington, D.C. during the summer of 1974 and analyzed for 27 elements, including coal, oil and refuse combustion, marine aerosols, soil and motor vehicle emissions.
TL;DR: In this paper, the authors consider a network-interdiction problem in which the shortest path from source node s to sink node t is to be increased to at least τ units via a least-cost investment strategy.
Abstract: Suppose we are given a network G=(V,E) with arc distances and a linear cost function for lengthening arcs. In this note, we consider a network-interdiction problem in which the shortest path from source node s to sink node t is to be increased to at least τ units via a least-cost investment strategy. This problem is shown to reduce to a simple minimum-cost-flow problem. Applications and generalizations are discussed, including the multiple-destination case.
TL;DR: Visual sensitivity is not reduced by smooth pursuit eye movements, which imply that the visibility of moving objects is primarily limited by velocity errors of smooth pursuitEye movements for the range of target velocities studied.
TL;DR: Six stable alcoholic cirrhotics with serum zinc with abnormaldark adaptation responses had abnormal dark adaptation responses and one patient, treated with vitamin A and zinc together, attained a normal final threshold in 2 weeks, suggesting improvement in dark adaptation by zinc may be due to enhanced activity of previously depressed retinol dehydrogenase.
TL;DR: In this paper, a program of exploring harmonic mapping theories to see whether they may provide models of physical phenomena that are either not recognized, or that are not well fitted to more familiar field theories.
Abstract: Harmonic maps are an aesthetically appealing class of nonlinear field equations of which only a few nontrivial examples have as yet appeared in physical theories. These fields appear well suited for describing broken symmetries either in conjunction with or instead of the Yang-Mills equations. The harmonic mapping equation is quite similar in many respects to the Einstein equations for gravitation, although simpler in structure, and can describe any gauge symmetry group G broken to a subgroup H in a sense parallel to the way the gravitational (metric) field breaks general covariance (local GL(4,R) invariance) down to local Lorentz invariance. This paper outlines the basis for a program of exploring harmonic mapping theories to see whether they may provide models of physical phenomena that are either not recognized, or that are not well fitted to more familiar field theories.
TL;DR: The inclusion of fruits and vegetables in the diet decreased bowel transit time, increased bowel weight, increased number of defecations, increased fecal excretions and decreased apparent digestibilities of energy, nitrogen, and fat.
TL;DR: In this article, a sufficient condition for the product of two Toeplitz operators to be a compact perturbation of one of them is found, which is shown to be necessary under additional hypotheses.
Abstract: A sufficient condition is found for the product of two Toeplitz operators to be a compact perturbation of a Toeplitz operator The condition, which comprehends all previously known sufficient conditions, is shown to be necessary under additional hypotheses The question whether the condition is necessary in general is left open
TL;DR: In this article, the effects of transverse compressional damping in the vibratory response of three-layer elastic-viscoelasticelastic beams are considered both analytically and experimentally in a mechanical impedance format.
Abstract: The effects of transverse compressional damping in the vibratory response of three-layer elastic-viscoelasticelastic beams are considered both analytically and experimentally in a mechanical impedance format. The relative importance of this type of damping is assessed through comparison with the shear damping mechanism inherent in the composite using the Mead and Markus model. Results of this investigation suggest that the effects from transverse compressional damping have a relatively narrow frequency bandwidth dependent on the elastic loss tangent of the damping core and are centered at the compressional (delamination) frequency toc of the composite. Compressional damping is shown to have a minimal effect on the transverse dynamic response of thin three-layer damped beams for frequencies significantly less than coc where a shear damping model provides a more accurate prediction of the composite loss factor. / £ tv /,b EI Pi
TL;DR: In this article, the authors reviewed literature on sex differences in three areas of importance to leadership research and found few differences between male and female leaders, and suggested the use of a framework based on Schein's (68) career stages for further analysis of the sex structuring phenomenon.
Abstract: Attempting to account for the sex structuring of organizations, this article reviews literature on sex differences in three areas of importance to leadership research. Finding few differences between male and female leaders, the article suggests the use of a framework based on Schein's (68) career stages for further analysis of the sex structuring phenomenon.