Showing papers by "University of Michigan published in 1986"

Development of criteria for the classification and reporting of osteoarthritis: Classification of osteoarthritis of the knee

Abstract: For the purposes of classification, it should be specified whether osteoarthritis (OA) of the knee is of unknown origin (idiopathic, primary) or is related to a known medical condition or event (secondary). Clinical criteria for the classification of idiopathic OA of the knee were developed through a multicenter study group. Comparison diagnoses included rheumatoid arthritis and other painful conditions of the knee, exclusive of referred or para-articular pain. Variables from the medical history, physical examination, laboratory tests, and radiographs were used to develop sets of criteria that serve different investigative purposes. In contrast to prior criteria, these proposed criteria utilize classification trees, or algorithms.

Canonical Correspondence Analysis: A New Eigenvector Technique for Multivariate Direct Gradient Analysis

Abstract: A new multivariate analysis technique, developed to relate community composition to known variation in the environment, is described. The technique is an extension of correspondence analysis (reciprocal averaging), a popular ordination technique that extracts continuous axes of variation from species occurrence or abundance data. Such ordination axes are typically interpreted with the help of external knowledge and data on environmental variables; this two—step approach (ordination followed by environmental gradient identification) is termed indirect gradient analysis. In the new technique, called canonical correspondence analysis, ordination axes are chosen in the light of known environmental variables by imposing the extra restriction that the axes be linear combinations of environmental variables. In this way community variation can be directly related to environmental variation. The environmental variables may be quantitative or nominal. As many axes can be extracted as there are environmental variables. The method of detrending can be incorporated in the technique to remove arch effects. (Detrended) canonical correspondence analysis is an efficient ordination technique when species have bell—shaped response curves or surfaces with respect to environmental gradients, and is therefore more appropriate for analyzing data on community composition and environmental variables than canonical correlation analysis. The new technique leads to an ordination diagram in which points represent species and sites, and vectors represent environmental variables. Such a diagram shows the patterns of variation in community composition that can be explained best by the environmental variables and also visualizes approximately the "centers" of the species distributions along each of the environmental variables. Such diagrams effectively summarized relationships between community and environment for data sets on hunting spiders, dyke vegetation, and algae along a pollution gradient.

The dominant logic: A new linkage between diversity and performance

Abstract: Current research offers alternative explanations to the “linkage” between the pattern of diversification and performance At least four streams of research can be identified None of these can be considered to be a reliable, predictive theory of successful diversification They are, at best, partial explanations The purpose of this paper is to propose an additional “linkage,” conceptual at this stage, that might help our understanding of the crucial connection between diversity and performance The conceptual argument is intented as a “supplement” to the current lines of research, rather than as an alternative explanation

Vibrational spectroscopy and conformation of peptides, polypeptides, and proteins.

Abstract: Publisher Summary The vibrational spectrum of a molecule is determined by its three-dimensional structure and its vibrational force field. An analysis of this (usually infrared (IR) and Raman) spectrum can therefore provide information on the structure and on intramolecular and intermolecular interactions. The more probing the analysis, the more detailed is the information that can be obtained. Detailed analyses of the vibrational spectra of macromolecules, however, have provided a deeper understanding of structure and interactions in these systems. An important advance in this direction for proteins came with the determination of the normal modes of vibration of the peptide group in N-methylacetamide, and the characterization of several specific amide vibrations in polypeptide systems. Extensive use has been made of spectra-structure correlations based on some of these amide modes, including attempts to determine secondary structure composition in proteins. Polypeptide molecules exhibit many more vibrational frequencies than the amide modes. Over the years, some normal-mode calculations have provided greater insight into the spectra of particular molecules. However, these have often been based on approximate structures or have employed limited force fields. These force fields can now serve as a basis for detailed analyses of spectral and structural questions in other polypeptide molecules. The aim of this chapter is to present these recent developments in the vibrational spectroscopy of peptides, polypeptides, and proteins.

An evolutionary approach to norms

Abstract: Iorms provide a powerful mechanism for regulating conflict in groups, even when there are more than two people and no central authority. This paper investigates the emergence and stability of behavioral norms in the context of a game played by people of limited rationality. The dynamics of this new norms game are analyzed with a computer simulation based upon the evolutionary principle that strategies shown to be relatively effective will be used more in the future than less effective strategies. The results show the conditions under which norms can evolve and prove stable. One interesting possibility is the employment of metanorms, the willingness to punish someone who did not enforce a norm. Many historical examples of domestic and international norms are used to illustrate the wide variety of mechanisms that can support norms, including metanorms, dominance, internalization, deterrence, social proof, membership in groups, law, and reputation.

The Role of Self-Efficacy in Achieving Health Behavior Change

Abstract: The concept of self-efficacy is receiving increasing recognition as a predictor of health behavior change and maintenance. The purpose of this article is to facilitate a clearer understanding of both the concept and its relevance for health education research and practice. Self-efficacy is first defined and distinguished from other related concepts. Next, studies of the self-efficacy concept as it relates to health practices are examined. This review focuses on cigarette smoking, weight control, contraception, alcohol abuse and exercise behaviors. The studies reviewed suggest strong relationships between self-efficacy and health behavior change and maintenance. Experimental manipulations of self-efficacy suggest that efficacy can be enhanced and that this enhancement is related to subsequent health behavior change. The findings from these studies also suggest methods for modifying health practices. These methods diverge from many of the current, traditional methods for changing health practices. Recommend...

Perceived support, received support, and adjustment to stressful life events.

Abstract: A systematic review of the literature on social support shows that a stress-buffering effect is most consistently found when support is measured as a perception that one's network is ready to provide aid and assistance if needed (Kessler and McLeod, 1985). Two interpretations of this association are considered here: (I) that the perception of support availability indirectly indicates actual network responses to stressful events that more directly promote healthy adjustment; and (2) that the perception of support availability influences adjustment directly by modifying appraisals of the situation. No attempt has been made in the literature to discriminate between these two interpretations. One reason is that a strategy for critically evaluating the competing hypotheses has not yet been developed. A main contribution of our paper is that it exposits such a strategy. A rigorous evaluation of the competing interpretations requires a prospective research design and a data collection effort explicitly aimed at obtaining information about both actual support transactions and perceptions of support availability in hypothetical situations. We know of no data set that meets these dual requirements. As an illustration of the strategy suggested here, however, we analyze cross-sectional data from a large-scale national survey. Although limited, these data provide provisional information about the competing interpretations. Analysis shows that perceived support is, in general, more important than received support in predicting adjustment to stressful life events. We also present evidence that the influence of received support may be mediated by perceived support. These results demonstrate the power of the strategy and argue for a direct evaluation with more appropriate data.

Preferences in human mate selection.

Abstract: In this article we examine preferences in mate choice within the broader context of the human mating system. Specifically, we discuss the consequences of mate preferences for the processes of assortative mating and sexual selection. In Study 1 (N = 184) we document (a) the mate characteristics that are consensually more and less desired, (b) the mate characteristics that show strong sex differences in their preferred value, (c) the degree to which married couples are correlated in selection preferences, and (d) the relations between expressed preferences and the personality and background characteristics of obtained spouses. In Study 2 (N = 100) we replicated the sex differences and consensual ordering of mate preferences found in Study I, using a different methodology and a differently composed sample. Lastly, we present alternative hypotheses to account for the replicated sex differences in preferences for attractiveness and earning potential. Neither men nor women prefer all members of the opposite sex equally. Some are favored over others, and one important research task is to identify the characteristics that prospective mates consider to be important. Although mate choice is clearly a crucial adult decision for more than 90% of the population (Price & Vandenberg, 1980), surprisingly little is known about the characteristics that men and women seek in potential mates (Thiessen & Gregg, 1980). In this article we develop a conception of the role of mate preferences within the human mating system. Specifically, we address the consequences for sexual selection and assortative mating. In two empirical studies we document several basic features of this conception.

Toward an understanding of the burnout phenomenon.

Abstract: Les auteurs decrivent les antecedents et les consequences du phenomene de «burnout» (Freudenberger, 1974) apparaissant dans certaines professions et constitue des trois composantes d'epuisement emotionnel de depersonnallisation et de sentiments d'echec personnel

Survey Questions: Handcrafting the Standardized Questionnaire

Abstract: This book reviews the experimental literature on how survey questions "behave" as well as the lore of professional experience and culls from them those guiding principles and specific findings that have implications for writing survey questions. Mindful that the findings of experiments cannot be applied mechanically and that survey questions cannot be mass-produced they have suggested a number of ways in which to make pilot and pretest work more fruitful. The authors have arranged ideas about writing questions in 3 classes or concentric circles which progressively narrow to the specific design task and the book is written in 3 chapters to match. Chapter 1 bears on general strategies culled from examples or experience of question-crafters and the findings of empirical researchers. This material is a litany of cautions offering more general perspectives than specific procedures. Chapter 2 focuses on specific empirical findings. In recent years there has been renewed research into question design and question effects and much has been learned about how some questions tend to "behave." But the implications of this research for actual practice are not always clear. Chapter 3 tries to zero in on the actual task at hand. It discusses pilot work pretesting and making use of the advice of experts--critics colleagues and especially interviewers. It is commonplace that all survey questions must be pretested but there is no commonly shared "tradition" about how to go about it. The authors are most familiar with questionnaires designed for use with the broad American public--national cross-sections drawn by the Institute for Social Research or samples of the greater Detroit metropolitan area by the Detroit Area Study so some of the cautions urged in chapter 1 may not apply to surveying the well educated or intensely motivated such as college students legislators social scientists political activists and medical patients.

Effectiveness as Paradox: Consensus and Conflict in Conceptions of Organizational Effectiveness

Abstract: Attention to the subject of organizational effectiveness has been increasing in the last several years as popular management books have extolled management excellence, almost two million jobs have been lost due to poor U.S. competitiveness, and economic conditions have put pressure on organizations to become more accountable with their resources. However, despite its popularity, much confusion continues in the organizational literature regarding the definition, circumscription, and appropriate criteria for assessing effectiveness. In this paper, I summarize what areas are becoming consensual among most writers on effectiveness, and I point out continuing areas of disagreement and conflict. The five statements summarizing consensual characteristics of effectiveness and the three statements summarizing areas of continuing conflict point out that agreement about effectiveness is mainly an agreement to disagree. Conflicts center mainly on the incompatibility and inappropriateness of commonly selected criteria. The main theme of the paper, however, is a discussion of an inherent, but largely ignored, characteristic of effectiveness in organizations-the paradoxical nature of effectiveness criteria. This discussion illustrates that the most effective organizations are also those characterized by paradoxes-i.e., contradictions, simultaneous opposites, and incompatibilities. Taking account of this characteristic helps explain one reason why so much confusion and disagreement continues to surround effectiveness, and it uncovers a new set of research questions that can guide future investigations. Some suggestions are provided for how research on paradoxes in effectiveness might be pursued in the future.

Fluorescent carbocyanine dyes allow living neurons of identified origin to be studied in long-term cultures

Abstract: A prerequisite for many studies of neurons in culture is a means of determining their original identity. We needed such a technique to study the interactions in vitro between a class of spinal cord neurons, sympathetic preganglionic neurons, and their normal target, neurons from the sympathetic chain. Here, we describe how we use two highly fluorescent carbocyanine dyes, which differ in color but are otherwise similar, to identify neurons in culture. The long carbon chain carbocyanine dyes we use are lipid-soluble and so become incorporated into the plasma membrane. Neurons can be labeled either retrogradely or during dissociation. Some of the labeled membrane gradually becomes internalized and retains its fluorescence, allowing identification of cells for several weeks in culture. These dyes do not affect the survival, development, or basic physiological properties of neurons and do not spread detectably from labeled to unlabeled neurons. It seems likely that cells become retrogradely labeled mainly by lateral diffusion of dye in the plane of the membrane. If so, carbocyanine dyes may be most useful for retrograde labeling over relatively short distances. An additional feature of carbocyanine labeling is that neuronal processes are brightly fluorescent for the first few days in culture, presumably because dye rapidly diffuses into newly inserted membrane. We have used carbocyanine dyes to identify sympathetic preganglionic neurons in culture. Our results indicate that preganglionic neurons can survive in the absence of their target cells and that several aspects of their differentiation in the absence of target appear normal.

A logical design methodology for relational databases using the extended entity-relationship model

Abstract: A database design methodology is defined for the design of large relational databases. First, the data requirements are conceptualized using an extended entity-relationship model, with the extensions being additional semantics such as ternary relationships, optional relationships, and the generalization abstraction. The extended entity-relationship model is then decomposed according to a set of basic entity-relationship constructs, and these are transformed into candidate relations. A set of basic transformations has been developed for the three types of relations: entity relations, extended entity relations, and relationship relations. Candidate relations are further analyzed and modified to attain the highest degree of normalization desired.The methodology produces database designs that are not only accurate representations of reality, but flexible enough to accommodate future processing requirements. It also reduces the number of data dependencies that must be analyzed, using the extended ER model conceptualization, and maintains data integrity through normalization. This approach can be implemented manually or in a simple software package as long as a "good" solution is acceptable and absolute optimality is not required.

Kinetic phase transitions in an irreversible surface-reaction model.

Abstract: An irreversible kinetic surface-reaction model, based upon the reaction of carbon monoxide and oxygen on a catalyst surface, is presented. It is found by computer simulation that the adsorbed molecules on the surface undergo both first- and second-order kinetic phase transitions. These transitions correspond to the "poisoning" phenomenon seen on catalysts. Interesting transient and periodic behavior is also seen.

Stability and malleability of the self-concept.

Abstract: The self-concept literature is characterized by a continuing controversy over whether the self-concept is stable or malleable. In this article we suggest that it is both but that the stability observed for general descriptions of the self may mask significant local variation. In this study the social environment was varied by creating a situation in which subjects found themselves to be either very unique or very similar to others. Following this manipulation, subjects responded to a series of self-concept measures. Although the uniqueness and similarity subjects did not differ in the trait terms they used to describe themselves, they did differ systematically in their latency for these judgments, in positivity and negativity of their word associations, and in their judgments of similarity to reference groups. These findings imply that subjects made to feel unique recruited conceptions of themselves as similar to others, whereas subjects made to feel similar to others recruited conceptions of themselves as unique. The results suggest that very general self-descriptive measures are inadequate for revealing how the individual adjusts and calibrates the self-concept in response to challenges from the social environment.

Microwave Remote Sensing Active and Passive-Volume III: From Theory to Applications

Abstract: Aspects of volume scattering and emission theory are discussed, taking into account a weakly scattering medium, the Born approximation, first-order renormalization, the radiative transfer method, and the matrix-doubling method. Other topics explored are related to scatterometers and probing systems, the passive microwave sensing of the atmosphere, the passive microwave sensing of the ocean, the passive microwave sensing of land, the active microwave sensing of land, and radar remote sensing applications. Attention is given to inversion techniques, atmospheric attenuation and emission, a temperature profile retrieval from ground-based observations, mapping rainfall rates, the apparent temperature of the sea, the emission behavior of bare soil surfaces, the emission behavior of vegetation canopies, the emission behavior of snow, wind-vector radar scatterometry, radar measurements of sea ice, and the back-scattering behavior of cultural vegetation canopies.

Cloning the gene for an inherited human disorder—chronic granulomatous disease—on the basis of its chromosomal location

Abstract: The gene that is abnormal in the X-linked form of the phagocytic disorder chronic granulomatous disease has been cloned without reference to a specific protein by relying on its chromosomal map position. The transcript of the gene is expressed in the phagocytic lineage of haematopoietic cells and is absent or structurally abnormal in four patients with the disorder. The nucleotide sequence of complementary DNA clones predicts a polypeptide of at least 468 amino acids with no homology to proteins described previously.

Evaluation of linear models of surface spectral reflectance with small numbers of parameters

Abstract: Recent computational models of color vision demonstrate that it is possible to achieve exact color constancy over a limited range of lights and surfaces described by linear models. The success of these computational models hinges on whether any sizable range of surface spectral reflectances can be described by a linear model with about three parameters. In the first part of this paper, I analyze two large sets of empirical surface spectral reflectances and examine three conjectures concerning constraints on surface reflectance: that empirical surface reflectances fall within a linear model with a small number of parameters, that empirical surface reflectances fall within a linear model composed of band-limited functions with a small number of parameters, and that the shape of the spectral-sensitivity curves of human vision enhance the fit between empirical surface reflectances and a linear model. I conclude that the first and second conjectures hold for the two sets of spectral reflectances analyzed but that the number of parameters required to model the spectral reflectances is five to seven, not three. A reanalysis of the empirical data that takes human visual sensitivity into account gives more promising results. The linear models derived provide excellent fits to the data with as few as three or four parameters, confirming the third conjecture. The results suggest that constraints on possible surface-reflectance functions and the "filtering" properties of the shapes of the spectral-sensitivity curves of photoreceptors can both contribute to color constancy. In the last part of the paper I derive the relation between the number of photoreceptor classes present in vision and the "filtering" properties of each class. The results of this analysis reverse a conclusion reached by Barlow: the "filtering" properties of human photoreceptors are consistent with a trichromatic visual system that is color constant.

Hand wrist cumulative trauma disorders in industry.

Abstract: A total of 574 active workers from six different industrial sites were categorised into four force repetitive exposure groups. Workers in low force-low repetitive jobs served as an internal comparison population for the three other groups. Videotapes and surface electromyography were used to estimate hand force and repetitiveness. The presence of cumulative trauma disorders (CTD) was determined by structured interview and standardised non-invasive physical examination. Only workers who had been working on the study jobs for at least one year at the time of evaluation were eligible for selection. Categorisation of jobs and identification of CTDs were carried out independently by investigators who were appropriately blinded to exposure and outcome. The analysis of associations between CTDs and exposure categories were performed using Mantel-Haenszel plant adjusted odds ratios and unconditional multiple logistic regression. Significant positive associations were observed between hand wrist CTDs and high force-high repetitive jobs. These associations were independent of age, sex, years on the specific job, and plant.

Size and Shape Spaces for Landmark Data in Two Dimensions

Abstract: Biometric studies of the forms of organisms usually consider size and shape variations in the geometric configuration of landmarks, points that correspond biologically from form to form. The size variables may be usefully considered the linear vector space spanned by the set of all distances between pairs of landmarks. The shape of a single triangle $\Delta ABC$ of landmarks may be reduced to a single pair of shape coordinates locating the vertex $C$ in the coordinate system with landmark $A$ sent to (0,0) and landmark $B$ to (1,0). A useful space of shape variables is the span of all such shape coordinate pairs for various triples of landmarks. On a convenient null model of identical circular normal perturbations at each landmark independently, one size variable $S$, which may be taken as the mean square of all the interlandmark distances, has covariance zero with every shape variable. Then associations between shape and size may be tested by the $F$ ratio for multiple regression of $S$ on any basis for shape space. For a single triangle of landmarks, the existence of any mean difference or mean change in shape may be tested by Hotelling's $T^2$ applied to any pair of shape coordinates for that triangle. When such a difference is statistically significant, it may be interpreted as the ratio of a pair of size variables measured along directions at an angle averaging $90^\circ$ in the samples of forms. One size variable will bear the greatest mean rate or ratio of change between the forms, the other the least. Analysis of configurations of more than three landmarks reduces to consideration of size variables involving at most three landmarks. These techniques are demonstrated in a study of the growth of the head in 62 normal Ann Arbor youth. Each comparison of interest is summarized in its own orthogonal coordinate system, the biorthogonal grid pair.

Invariant surface characteristics for 3D object recognition in range images

Abstract: In recent years there has been a tremendous increase in computer vision research using range images (or depth maps) as sensor input data. The most attractive feature of range images is the explicitness of the surface information. Many industrial and navigational robotic tasks will be more easily accomplished if such explicit depth information can be efficiently obtained and interpreted. Intensity image understanding research has shown that the early processing of sensor data should be data-driven. The goal of early processing is to generate a rich description for later processing. Classical differential geometry provides a complete local description of smooth surfaces. The first and second fundamental forms of surfaces provide a set of differential-geometric shape descriptors that capture domain-independent surface information. Mean curvature and Gaussian curvature are the fundamental second-order surface characteristics that possess desirable invariance properties and represent extrinsic and intrinsic surface geometry respectively. The signs of these surface curvatures are used to classify range image regions into one of eight basic viewpoint-independent surface types. Experimental results for real and synthetic range images show the properties, usefulness, and importance of differential-geometric surface characteristics.