Showing papers by "Ohio State University published in 1992"
TL;DR: In this paper, two types of error involved in fitting a model are considered, error of approximation and error of fit, where the first involves the fit of the model, and the second involves the model's shape.
Abstract: This article is concerned with measures of fit of a model. Two types of error involved in fitting a model are considered. The first is error of approximation which involves the fit of the model, wi...
25,611 citations
TL;DR: The motor system in the present case is defined as including the visual and proprioceptive feedback loops that permit S to monitor his own activity, and the information capacity of the motor system is specified by its ability to produce consistently one class of movement from among several alternative movement classes.
Abstract: Information theory has recently been employed to specify more precisely than has hitherto been possible man's capacity in certain sensory, perceptual, and perceptual-motor functions (5, 10, 13, 15, 17, 18). The experiments reported in the present paper extend the theory to the human motor system. The applicability of only the basic concepts, amount of information, noise, channel capacity, and rate of information transmission, will be examined at this time. General familiarity with these concepts as formulated by recent writers (4, 11,20, 22) is assumed. Strictly speaking, we cannot study man's motor system at the behavioral level in isolation from its associated sensory mechanisms. We can only analyze the behavior of the entire receptor-neural-effector system. However, by asking 51 to make rapid and uniform responses that have been highly overlearned, and by holding all relevant stimulus conditions constant with the exception of those resulting from 5"s own movements, we can create an experimental situation in which it is reasonable to assume that performance is limited primarily by the capacity of the motor system. The motor system in the present case is defined as including the visual and proprioceptive feedback loops that permit S to monitor his own activity. The information capacity of the motor system is specified by its ability to produce consistently one class of movement from among several alternative movement classes. The greater the number of alternative classes, the greater is the information capacity of a particular type of response. Since measurable aspects of motor responses, such as their force, direction, and amplitude, are continuous variables, their information capacity is limited only by the amount of statistical variability, or noise, that is characteristic of repeated efforts to produce the same response. The information capacity of the motor Editor's Note. This article is a reprint of an original work published in 1954 in the Journal of Experimental Psychology, 47, 381391.
7,599 citations
TL;DR: Results demonstrate that over repeated samples, model modifications may be very inconsistent and cross-validation results may behave erratically, leading to skepticism about generalizability of models resulting from data-driven modifications of an initial model.
Abstract: In applications of covariance structure modeling in which an initial model does not fit sample data well, it has become common practice to modify that model to improve its fit. Because this process is data driven, it is inherently susceptible to capitalization on chance characteristics of the data, thus raising the question of whether model modifications generalize to other samples or to the population. This issue is discussed in detail and is explored empirically through sampling studies using 2 large sets of data. Results demonstrate that over repeated samples, model modifications may be very inconsistent and cross-validation results may behave erratically. These findings lead to skepticism about generalizability of models resulting from data-driven modifications of an initial model. The use of alternative a priori models is recommended as a preferred strategy.
1,492 citations
University of Minnesota1, University of California, Los Angeles2, University of Oklahoma3, Ohio State University4, Rush University Medical Center5, University of Pittsburgh6, University of California, San Diego7, Loyola University Chicago8, University of Texas Health Science Center at San Antonio9, University of Washington10, University of Pennsylvania11, New York Medical College12, Cleveland Clinic13, Vanderbilt University14, Temple University15, University of Michigan16, Pfizer17
TL;DR: Prophylactic administration of fluconazole to recipients of bone marrow transplants reduces the incidence of both systemic and superficial fungal infections.
Abstract: Background and Methods. Superficial and systemic fungal infections are a major problem among severely immunocompromised patients who undergo bone marrow transplantation. We performed a doubleblind, randomized, multicenter trial in which patients receiving bone marrow transplants were randomly assigned to receive placebo or fluconazole (400 mg daily). Fluconazole or placebo was administered prophylactically from the start of the conditioning regimen until the neutrophil count returned to 1000 per microliter, toxicity was suspected, or a systemic fungal infection was suspected or proved. Results. By the end of the treatment period, 67.2 percent of the 177 patients assigned to placebo had a positive fungal culture of specimens from any site, as compared with 29.6 percent of the 179 patients assigned to fluconazole. Among these, superficial infections were diagnosed in 33.3 percent of the patients receiving placebo and in 8.4 percent of the patients receiving fluconazole (P<0.001). Systemic fungal in...
1,116 citations
TL;DR: The authors investigated the effect of bankruptcy announcements on the equity value of the bankrupt firm's competitors and found that bankruptcy announcements decrease the value of a value-weighted portfolio of competitors by 1%.
933 citations
01 Jan 1992
913 citations
TL;DR: In this article, a class of inherently nonlinear control problems arising directly from physical assumptions about constraints on the motion of a mechanical system is identified and a general procedure for constructing a piecewise analytic state feedback which achieves the desired result is suggested.
Abstract: A class of inherently nonlinear control problems has been identified, the nonlinear features arising directly from physical assumptions about constraints on the motion of a mechanical system. Models are presented for mechanical systems with nonholonomic constraints represented both by differential-algebraic equations and by reduced state equations. Control issues for this class of systems are studied and a number of fundamental results are derived. Although a single equilibrium solution cannot be asymptotically stabilized using continuous state feedback, a general procedure for constructing a piecewise analytic state feedback which achieves the desired result is suggested. >
857 citations
TL;DR: In this paper, the authors compared family-owned and -managed and professionally managed firms and found that significant differences exist between these two groups on both structural and process dimensions, and there is evidence that family-managed firms exhibit performance advantages as a result of the unification of ownership and control.
Abstract: The literature applying agency theory to management has focused on the performance advantages to be gained when ownership and control of the firm are aligned. This article investigates that premise by comparing family-owned and -managed and professionally managed firms. The article presents the results of a field survey that examined the extent to which family-owned and -managed firms differ across structural, process, and performance dimensions from their professionally managed counterparts. Significant differences exist between these two groups on both structural and process dimensions, and there is evidence that family-owned and -managed firms exhibit performance advantages as a result of the unification of ownership and control.
779 citations
01 Jan 1992
777 citations
TL;DR: In this article, the authors develop a theory of competitive rationality that proposes that a firm's success depends on the imperfect procedural rationality of its marketing planners, and that the success of a firm depends on its own imperfect rationality.
Abstract: The author develops a theory of competitive rationality that proposes a firm's success depends on the imperfect procedural rationality of its marketing planners. Theories of economic psychology and...
719 citations
01 Jan 1992
TL;DR: In this article, a correct variance-covariance estimate that takes account of the intra-group correlation is proposed, and power comparisons are performed to show the advantage of the new proposal.
Abstract: The Cox regression model has been used extensively to analyze survival data. For data that consist of large numbers of small groups of correlated failure time observations, we show that the standard maximum partial likelihood estimate of the regression coefficient in the Cox model is still consistent and asymptotically normal. However, the corresponding standard variance-covariance estimate may no longer be valid due to the dependence among members in the groups. In this article, a correct variance-covariance estimate that takes account of the intra-group correlation is proposed. Power comparisons are performed to show the advantage of the new proposal. Examples are provided for illustration.
TL;DR: In this paper, critical frames in educational research: Feminist and post-structural perspectives are discussed, with a focus on the intersectionality of women and women's perspectives in education.
Abstract: (1992). Critical frames in educational research: Feminist and post‐structural perspectives. Theory Into Practice: Vol. 31, Qualitative Issues in Educational Research, pp. 87-99.
TL;DR: Elevated immunoreactive endothelin-1 specifically correlated with the extent of pulmonary hypertension in congestive heart failure patients, suggesting it is a regional mediator ofmonary hypertension or a marker for its occurrence requires additional evaluation.
Abstract: BACKGROUNDEndothelin is a family of potent vasoconstrictor peptides of vascular endothelial origin. Although it has been proposed that the vasoconstrictor effects of endothelin are produced at the ...
TL;DR: Using strict conformity with Porter and Steer's (1973) definition of met expectations, a subset of studies was identified that had nonsignificant between-studies variance for all correlations except job satisfaction and the mean correlations in these subgroups were very similar to those for the entire group.
Abstract: A review of research on the effects of met expectations for newcomers to organizations located 31 studies of 17,241 people. A meta-analysis found mean (corrected) correlations of .39 for job satisfaction and organizational commitment, .29 for intent to leave, .19 for job survival, and .11 for job performance. However, all of these mean correlations had significant between-studies variance. By using strict conformity with Porter and Steer's (1973) definition of met expectations, we identified a subset of studies that had nonsignificant between-studies variance for all correlations except job satisfaction. Furthermore, the mean correlations in these subgroups were very similar to those for the entire group. Future research should consider both the direction of the met expectations discrepancy (i.e., over- vs. underfulfillment) and alternative ways to measure organizational reality.
TL;DR: In this article, three studies were conducted to examine the role of need for cognition on attitudes formed as a result of exposure to advertisements and found that attitudes of high need for cognitive ability individuals were based more on an evaluation of product attributes than were the attitudes of low need to cognition persons.
TL;DR: The problem of judiciously and transparently redistributing the load of the system among its nodes so that overall performance is maximized is discussed and conclusions about which algorithm might help in realizing the most benefits of load distributing are drawn.
Abstract: The problem of judiciously and transparently redistributing the load of the system among its nodes so that overall performance is maximized is discussed. Several key issues in load distributing for general-purpose systems, including the motivations and design trade-offs for load-distributing algorithms, are reviewed. In addition, several load-distributing algorithms are described and their performances are compared. These algorithms are sender-initiated algorithms, receiver-initiated algorithms, symmetrically initiated algorithms, and adaptive algorithms. Load-distributing policies used in existing systems are examined, and conclusions about which algorithm might help in realizing the most benefits of load distributing are drawn. >
TL;DR: In this article, two new techniques for the study of the linear and nonlinear instability in growing boundary layers are presented, one of which employs partial differential equations of parabolic type exploiting the slow change of the mean flow, disturbance velocity profiles, wavelengths, and growth rates in the streamwise direction.
Abstract: Two new techniques for the study of the linear and nonlinear instability in growing boundary layers are presented. The first technique employs partial differential equations of parabolic type exploiting the slow change of the mean flow, disturbance velocity profiles, wavelengths, and growth rates in the streamwise direction. The second technique solves the Navier-Stokes equation for spatially evolving disturbances using buffer zones adjacent to the inflow and outflow boundaries. Results of both techniques are in excellent agreement. The linear and nonlinear development of Tollmien-Schlichting (TS) waves in the Blasius boundary layer is investigated with both techniques and with a local procedure based on a system of ordinary differential equations. The results are compared with previous work and the effects of non-parallelism and nonlinearity are clarified. The effect of nonparallelism is confirmed to be weak and, consequently, not responsible for the discrepancies between measurements and theoretical results for parallel flow.
TL;DR: The quantitative determination of JA/MeJA in planta is reported by a procedure based on the use of [13C,2H3]MeJA as an internal standard suggesting a role for MeJA/JA in the mediation of several changes in gene expression associated with the plants' response to wounding.
Abstract: Jasmonic acid (JA) and its methyl ester, methyl jasmonate (MeJA), are plant lipid derivatives that resemble mammalian eicosanoids in structure and biosynthesis. These compounds are proposed to play a role in plant wound and pathogen responses. Here we report the quantitative determination of JA/MeJA in planta by a procedure based on the use of [13C,2H3]MeJA as an internal standard. Wounded soybean (Glycine max [L] Merr. cv. Williams) stems rapidly accumulated MeJA and JA. Addition of MeJA to soybean suspension cultures also increased mRNA levels for three wound-responsive genes (chalcone synthase, vegetative storage protein, and proline-rich cell wall protein) suggesting a role for MeJA/JA in the mediation of several changes in gene expression associated with the plants' response to wounding.
TL;DR: In this paper, the authors examined the effect of self-reported maintenance strategies, perception of partners' maintenance strategies and equity in predicting relational characteristics and found that maintenance strategies are used more in equitable relationships than in relationships characterized by under-benefit.
Abstract: Utilizing equity theory, this study extends previous research on maintenance strategies. The manner in which relational maintenance strategies are reported and perceived is examined. It was hypothesized that maintenance strategies are used more in equitable relationships than in relationships characterized by underbenefitedness. Further, the use of maintenance efforts by individuals in overbenefited relationships was explored. In addition, this study examined the relative contribution of self‐reported maintenance strategies, perception of partners’ maintenance strategies, and equity in predicting the relational characteristics. Overall, the level of felt equity was found to be related to individuals’ use of, and perceptions of partners’ use of, maintenance strategies in a pattern consistent with equity theory. However, the findings varied somewhat when relying on wives’ versus husbands’ equity judgments. Moreover, self‐reported maintenance strategies as well as perceptions of partners’ maintenance strateg...
TL;DR: In this article, the authors discuss several composites or granular or porous materials that display inhomogeneity on a macroscopic scale and present a discussion of the effective medium approximation, electrostatic resonances, exact bounds, and analytical properties.
Abstract: Publisher Summary This chapter discusses several composites or granular or porous materials that display inhomogeneity on a macroscopic scale. In such materials, there are small, yet much larger than atomic, regions exhibiting macroscopic homogeneity. Different regions may display quite different properties. The chapter discusses the dc and ac electrical properties of composite media including the basic theory and results for dc electrical properties. It also presents a discussion of the effective-medium approximation, electrostatic resonances, exact bounds, and analytical properties and describes a number of static physical properties of composites. These properties include electrical conductivity and dielectric behavior near a percolation threshold, magnetotransport, thermoelectricity, superconductivity, and duality in two-dimensional composites. Finally, the chapter discusses the nonlinear properties and flicker noise in composites.
TL;DR: The isolation of a mothbean cDNA clone encoding a bifunctional enzyme, delta 1-pyrroline-5-carboxylate synthetase (P5CS), with both gamma-glutamyl kinase and glutamic-gamma-semialdehyde dehydrogenase activities that catalyzes the first two steps in proline biosynthesis suggests that P5CS plays a key role in prolinesynthesis, leading to osmoregulation in plants.
Abstract: Many plants synthesize and accumulate proline in response to osmotic stress. Despite the importance of this pathway, however, the exact metabolic route and enzymes involved in the synthesis of proline in plants have not been unequivocally identified. We report here the isolation of a mothbean (Vigna aconitifolia) cDNA clone encoding a bifunctional enzyme, delta 1-pyrroline-5-carboxylate synthetase (P5CS), with both gamma-glutamyl kinase and glutamic-gamma-semialdehyde dehydrogenase activities that catalyzes the first two steps in proline biosynthesis. The two enzymatic domains of P5CS correspond to the ProB and ProA proteins of Escherichia coli and contain a leucine zipper in each domain, which may facilitate inter- or intramolecular interaction of this protein. The Vigna P5CS enzyme activity is feedback regulated by proline but is less sensitive to end-product inhibition than is the E. coli gamma-glutamyl kinase. The P5CS gene is expressed at high levels in Vigna leaves and is inducible in roots subjected to salt stress, suggesting that P5CS plays a key role in proline biosynthesis, leading to osmoregulation in plants.
TL;DR: The DNA sequences associated with 139 apparent streptomycete transcriptional start sites are compiled and compared and an updated consensus sequence for the E sigma 70-like promoters is proposed and a potential group of promoter sequences containing guanine-rich -35 regions also is identified.
Abstract: The DNA sequences associated with 139 apparent streptomycete transcriptional start sites are compiled and compared. Of these, 29 promoters appeared to belong to a group which are similar to those recognized by eubacterial RNA polymerases containing sigma 70-like subunits. The other 110 putative promoter regions contain a wide diversity of sequences; several of these promoters have obvious sequence similarities in the -10 and/or -35 regions. The apparent Shine-Dalgarno regions of 44 streptomycete genes are also examined and compared. These were found to have a wide range of degree of complementarity to the 3' end of streptomycete 16S rRNA. Eleven streptomycete genes are described and compared in which transcription and translation are proposed to be initiated from the same or nearby nucleotide. An updated consensus sequence for the E sigma 70-like promoters is proposed and a potential group of promoter sequences containing guanine-rich -35 regions also is identified.
TL;DR: Structural and biochemical changes probably contribute to the decreases in muscle mass, strength, and endurance often observed in healthy but sedentary older men and women.
Abstract: To examine the effects of aging on human skeletal muscle, 10 men and 10 women, 64 +/- 1 yr old (Mean +/- SE), and 10 men and 10 women, 24 +/- 1 yr old, were studied. All subjects were sedentary nonsmokers who were carefully screened for latent cardiovascular, metabolic, or musculoskeletal disease. Needle biopsy samples were obtained from the lateral gastrocnemius muscle and examined using histochemical and biochemical techniques. The percentage of Type I, Type IIa, and Type IIb fibers did not differ with age. However, Type I fibers occupied a larger percent of total muscle area in the older men and women (60.6 +/- 2.6 vs 53.6 +/- 2.0%; p less than .05), because Type IIa and Type IIb fibers were 13-31% smaller (p less than .001) in these subjects. Muscle capillarization and mitochondrial enzyme (i.e., succinate dehydrogenase, citrate synthase, and beta-hydroxyacyl-CoA dehydrogenase) activities were also approximately 25% lower (p less than .001-.05) in the old subjects. Although it is difficult to determine whether these differences are due to aging itself or are simply due to inactivity, these structural and biochemical changes probably contribute to the decreases in muscle mass, strength, and endurance often observed in healthy but sedentary older men and women.
TL;DR: As uniquely adapted tissue resident macrophages within the CNS, microglia serve a variety of functional roles over the lifespan of this tissue and may be involved in or contribute to some disease states.
TL;DR: Experimental and quasi-experimental studies of psychological interventions are reviewed, and discussion of treatment components and mechanism is offered.
Abstract: Although the thrust of the nation’s cancer objectives for the year 2000 is prevention and screening, each year approximately 1 million Americans are diagnosed and must cope with the disease and treatments. They do so with the aid of family, friends, and the health care system, but accumulating data suggest that psychological interventions may be important for reducing emotional distress, enhancing coping, and improving “adjustment.” Experimental and quasi-experimental studies of psychological interventions are reviewed, and discussion of treatment components and mechanism is offered. A final section discusses future research directions and challenges to scientific advance.
TL;DR: In this paper, the authors considered a survival experiment where individuals within a certain subset of the population share a common, unobservable, random frailty and used an EM algorithm based on profile likelihood construction to estimate the fixed and random effects.
Abstract: Consider a survival experiment where individuals within a certain subset of the population share a common, unobservable, random frailty. Such a frailty could be an unobservable genetic or early environmental effect if individuals were in sibling groups or an environmental effect if individuals were grouped by households. Suppose that if the frailty, omega, is known, the Cox proportional hazards model for the observable covariates is valid with the consequence of the random effect being a multiplicative factor on the hazard rate. Assuming tht the random frailties follow a gamma distribution, estimates of the fixed and random effects are obtained by using an EM algorithm based on a profile likelihood construction. The method developed is applied to the Framingham Heart Study to examine the risks of smoking and cholesterol levels, adjusting for potential random effects.
TL;DR: An improved version of nonrelativistic QCD is constructed for use in lattice simulations of heavy-quark physics, and power-counting rules to assess the importance of the various operators in the action and compute all leading-order corrections required by relativity and finite lattice spacing are developed.
Abstract: We construct an improved version of nonrelativistic QCD for use in lattice simulations of heavy-quark physics, with the goal of reducing systematic errors from all sources to below 10%. We develop power-counting rules to assess the importance of the various operators in the action and compute all leading-order corrections required by relativity and finite lattice spacing. We discuss radiative corrections to tree-level coupling constants, presenting a procedure that effectively resums the largest such corrections to all orders in perturbation theory. Finally, we comment on the size of nonperturbative contributions to the coupling constants.
TL;DR: For instance, Cacioppo et al. as mentioned in this paper found that high-NC and low-NC individuals formed evaluatively similar attitudes toward an unfamiliar attitude object (a new product) after exposure to a persuasive message (an advertisement).
Abstract: Hypotheses about the persistence and resistance of attitudes and beliefs formed by individuals scoring high or low in Need for Cognition (NC; Cacioppo & Petty, 1982) were derived from the Elaboration Likelihood Model of persuasion (Petty & Cacioppo, 1986). In Study 1, both high-NC and low-NC individuals formed evaluatively similar attitudes toward an unfamiliar attitude object (a new product) after exposure to a persuasive message (an advertisement). The newly formed attitudes of high-NC individuals decayed less than the newly formed attitudes of low-NC individuals over a 2-day period. In Study 2, both high-NC and low-NC individuals were persuaded by an initial message that a food additive was unsafe. However, when immediately exposed to a second countermessage arguing that the product was safe, the initial experimentally created beliefs of high-NC individuals were shown to be more resistant to change than the experimentally created beliefs of low-NC individuals. Understanding the role of individual difference factors in persuasion is of longstanding interest among personality and social psychologists. One of the earliest systematic efforts in the study of personality and persuasion was undertaken by Hovland and his colleagues at Yale in the 1940s and 1950s. Efforts of this group culminated in the publication of the book Personality and Persuasion (Hovland & Janis, 1959). A stated long-range goal of research by the Yale group was the development of general formulae "which could be used to predict, within a very narrow range of error, the degree to which any given person will be influenced by any given communication" (Janis & Hovland, 1959, p. 14). Self-report measures of influenceability, personality (e.g., self-esteem), and intellectual ability were all examined for their relationships to opinion change. Although the Yale group's goal of finding general factors associated with persuasibility was quite ambitious, the outcome was generally unsuccessful. Nevertheless, their efforts did lead to the consideration of a general theoretical structure in which individual attributes and persuasion were hypothesized to be linked (Hovland & Janis. 1959). Research on the role of personality factors in persuasion continued in several different directions after the publication of Personality and Persuasion. About 10 years ago, Eagly (1981) reviewed research in the area and outlined three general strategies for understanding the effects of individual differences in persuasion that had developed. In the personality strategy, a personality theory was used to identify traits that could affect