Showing papers by "University of Notre Dame published in 1991"

Fundamentals of fluid film lubrication

Abstract: 1: Introduction 2: Bearing Classification and Selection 3: Surface Topography 4: Lubricant Properties 5: Bearing Materials 6: Viscous Flow 7: Reynolds Equation 8: Hydrodynamic Thrust Bearings - Analytical Solutions 9: Hydrodynamic Thrust Bearings - Numerical Solutions 10: Hydrodynamic Journal Bearings - Analytical Solutions 11: Dynamically Loaded Journal Bearings 12: Hydrodynamic Journal Bearings - Numerical Solutions 13: Hydrodynamic Squeeze Film Bearings 14: Hydrostatic Lubrication 15: Hydrodynamic Bearings - Considering Fluid Inertia 16: Gas-Lubricated Thrust Bearings 17: Gas-Lubricated Journal Bearings 18: Hydrodynamic Lubrication of Nonconformal Surfaces 19: Simplified Solutions for Stresses and Deformations 20: General Solution for Stresses and Deformations in Dry Contacts 21: Elastohydrodynamic Lubrication of Rectangular Conjunctions 22: Elastohydrodynamic Lubrication of Ellipitcal Conjunctions 23: Film Thicknesses for Different Regimes of Fluid Film Lubrication 24: Rolling-Element Bearings 25: Additional Elastohydrodynamic Lubrication Applications 26: Non-Newtonian Fluid Effects in Elastohydrodynamic Lubrication 27: Thermo Elastohydrodynamic Lubrication.

Evolution of the Marketing Organization: New Forms for Turbulent Environments:

Abstract: Rapid changes in industrial structure and global competition have occurred in the last two decades. The changes herald the post-industrial era, producing an environment of ambiguity and paradox at ...

Indeterminacy and identifiability of blind identification

Abstract: Blind identification of source signals is studied from both theoretical and algorithmic aspects. A mathematical structure is formulated from which the acceptable indeterminacy is represented by an equivalence relation. The concept of identifiability is then defined. Two identifiable cases are shown along with blind identification algorithms. The performance of FOBI (fourth-order blind identification), EFOBI (extended FOBI), and AMUSE algorithms is evaluated by some heuristic arguments and simulation results. It is shown that EFOBI outperforms the FOBI algorithm, and the AMUSE algorithm performs better than EFOBI in the case of nonwhite source signals. AMUSE is applied to a speech extraction problem and shown to have promising results. >

The nature of nurture : genetic influence on «environmental» measures

Abstract: Evidence for genetic influence on environmental measures will emerge in quantitative genetic analyses if genetically influenced characteristics of individuals are assessed by these environmental measures Recent twin and adoption studies indicate substantial genetic influence when measures of the environment are treated as phenotypes in genetic analyses Genetic influence has been documented for measures as diverse as videotaped observations of parental behavior toward their children, ratings by parents and children of their family environment, and ratings of peer groups, social support, and life events Evidence for genetic influence on environmental measures includes some of the most widely used measures of environment – the Home Observation for Measurement of the Environment, the Family Environment Scales, and the Social Readjustment Rating Scale of life events, for example The goal of this article is to document and discuss these findings and to elicit commentary that might help to shape the course of research on this topic, which has far-reaching implications for the behavioral and brain sciences

Culture tales. A narrative approach to thinking, cross-cultural psychology, and psychotherapy.

Abstract: Narrative (or storytelling) approaches to understanding human action have recently become more popular in several areas of psychology. Treating human thinking as instances of story elaboration offers numerous implications for many domains of psychological theory, research, and practice. For example, several instances of cultural diversity take on a different hue when viewed from a narrative perspective. Finally, several authors (e.g., Bruner, 1986; Howard, 1989; Mair, 1989; McAdams, 1985; Polkinghorne, 1988; Sarbin, 1986) see the development of identity as an issue of life-story construction; psychopathology as instances of life stories gone awry; and psychotherapy as exercises in story repair.

Separation control - Review

Abstract: Under certain conditions, wall-bounded flows separate. To improve the performance of natural or man-made flow systems, it may be beneficial to delay or advance this detachment process. The present article reviews the status and outlook of separation control for both steady and unsteady flows. Both passive and active techniques to prevent or to provoke flow detachment are considered and suggestions are made for further research.

Stability of the pseudo-inverse method for reconfigurable control systems

Abstract: One of the key reconfigurable control methods, the pseudo-inverse method (PIM), is analysed and new insight is obtained which provides the theoretical basis for this practical approach. The main shortcoming of this method, the lack of stability guarantees, is pointed out and a new approach is proposed in which recent results on the stability robustness of linear systems are used to provide stability constraints for the solutions of the PIM. When the original PIM solution results in an unstable closed-loop system, the control redesign problem is treated as a constraint minimization problem. For single-input systems, a closed-form solution is presented; for multi-input systems, a near-optimal solution is found which maintains the stability of the closed-loop system.

Boson realizations of Lie algebras with applications to nuclear physics

Abstract: The concept of boson realization (or mapping) of Lie algebras appeared first in nuclear physics in 1962 as the idea of expanding bilinear forms in fermion creation and annihilation operators in Taylor series of boson operators, with the object of converting the study of nuclear vibrational motion into a problem of coupled oscillators. The physical situations of interest are quite diverse, depending, for instance, on whether excitations for fixed- or variable-particle number are being studied, on how total angular momentum is decomposed into orbital and spin parts, and on whether isotopic spin and other intrinsic degrees of freedom enter. As a consequence, all of the semisimple algebras other than the exceptional ones have proved to be of interest at one time or another, and all are studied in this review. Though the salient historical facts are presented in the introduction, in the body of the review the progression is (generally) from the simplest algebras to the more complex ones. With a sufficiently broad view of the physics requirements, the mathematical problem is the realization of an arbitrary representation of a Lie algebra in a subspace of a suitably chosen Hilbert space of bosons (Heisenberg-Weyl algebra). Indeed, if one includes the study of odd nuclei, one is forced to consider the mappings to spaces that are direct-product spaces of bosons and (quasi)fermions. Though all the methods that have been used for these problems are reviewed, emphasis is placed on a relatively new algebraic method that has emerged over the past decade. Many of the classic results are rederived, and some new results are obtained for odd systems. The major application of these ideas is to the derivation, starting from the shell model, of the phenomenological models of nuclear collective motion, in particular, the geometric model of Bohr and Mottelson and the more recently developed interacting boson model of Arima and Iachello. A critical discussion of those applications is interwoven with the theoretical developments on which they are based; many other applications are included, some of practical interest, some simply to illustrate the concepts, and some to suggest new lines of inquiry.

Bounds on the number of hidden neurons in multilayer perceptrons

Abstract: Fundamental issues concerning the capability of multilayer perceptrons with one hidden layer are investigated. The studies are focused on realizations of functions which map from a finite subset of E/sup n/ into E/sup d/. Real-valued and binary-valued functions are considered. In particular, a least upper bound is derived for the number of hidden neurons needed to realize an arbitrary function which maps from a finite subset of E/sup n/ into E/sup d/. A nontrivial lower bound is also obtained for realizations of injective functions. This result can be applied in studies of pattern recognition and database retrieval. An upper bound is given for realizing binary-valued functions that are related to pattern-classification problems. >

Measurement of atmospheric neutrino composition with the IMB-3 detector.

Abstract: The atmospheric neutrino flux is measured using a 3.4-kt yr exposure of the IMB-3 detector. Single-ring events are classified as showering or nonshowering using the geometry of the \ifmmode \check{C}\else \v{C}\fi{}erenkov pattern. A simulation of neutrino interactions and three models of atmospheric neutrino production are used to predict the composition of the sample. Showering-nonshowering character is strongly correlated with the flavor of the neutrino parent. In the lepton momentum range p1500 MeV/c, we find that nonshowering events comprise [41\ifmmode\pm\else\textpm\fi{}3\ifmmode\pm\else\textpm\fi{}2syst]% of the total. The fraction expected is [51\ifmmode\pm\else\textpm\fi{}5(syst)]%.

Preliminary support for a competency-based model of depression in children.

Abstract: The relation of child depression to competency feedback was explored in five domains: academic, social, physical attractiveness, conduct, and sports. Self-reports of depression and peer nominations of competency were obtained from 1,422 elementary school children. Findings supported 4 hypotheses from a competency-based model of child depression. Peer nominations of competency in various domains were negatively related to depression. Being nominated as relatively incompetent in multiple domains corresponded with higher levels of self-reported depression. Being nominated as competent in one or more domains corresponded with lower levels of depression. Individual differences in incompetency were more strongly related to depression than were those in competency, especially for girls. Early intervention in child depression is discussed. Longitudinal and experimental designs are recommended for testing further the competency-based model.

Prevention of primary prostate cancer in Lobund-Wistar rats by N-(4-hydroxyphenyl)retinamide.

Abstract: We report for the first time that a synthetic retinoid, N-(4-hydroxyphenyl)retinamide, can prevent the development of both primary and metastatic tumors in an animal model of metastasizing primary prostate cancer. Prostatic adenocarcinomas were induced in high incidence in Lobund-Wistar rats by initiation with methylnitrosourea i.v. and promotion with testosterone. Feeding of N-(4-hydroxyphenyl)retinamide to these rats during the latency period markedly diminished the final incidence of both primary and metastatic prostate carcinomas.

A simple method to derive bounds on the size and to train multilayer neural networks

Abstract: A new derivation is presented for the bounds on the size of a multilayer neural network to exactly implement an arbitrary training set; namely the training set can be implemented with zero error with two layers and with the number of the hidden-layer neurons equal to Hash 1>or=p-1. The derivation does not require the separation of the input space by particular hyperplanes, as in previous derivations. The weights for the hidden layer can be chosen almost arbitrarily, and the weights for the output layer can be found by solving Hash 1+1 linear equations. The method presented exactly solves (M), the multilayer neural network training problem, for any arbitrary training set. >

Fostering Ethical Marketing Decisions

Abstract: This paper begins by examining several potentially unethical recent marketing practices. Since most marketing managers face ethical dilemmas during their careers, it is essential to study the moral consequences of these decisions. A typology of ways that managers might confront ethical issues is proposed. The significant organizational, personal and societal costs emanting from unethical behavior are also discussed. Both relatively simple frameworks and more comprehensive models for evaluating ethical decisions in marketing are summarized. Finally, the fact that organizational commitment to fostering ethical marketing decisions can be accomplished by top management leadership, codes of ethics, ethics seminars/programs and ethical audits is examined.

Stability and stabilizability of discrete event dynamic systems

Abstract: A finite-state automaton is adopted as a model for Discrete Event Dynamic Systems (DEDS), Stabdity is defined as wslting a given set E mtinitely often. Stabilizability is defined as choosing state feedback such that the closed loop system is stable. These notions are proposed as properties of resiliency or error-recovery. An important ingredient in stability is shown to be a notion of transition- function-invariance. Relations between our notions of stability and invariance, and the notions of safety, fairness, hvelock, deadlock, etc., in computer science literature are pointed out. Connections are established between our notions of invariance and the classical notions of A -Invariance and (A. 11)-invariance of linear systems. Polynomial algorithms for testing stability and stabilizabdity, and for constructing a stabilizing control law are also presented.

Relativistic all-order calculations of energies and matrix elements in cesium

Abstract: All-order methods recently developed for high-accuracy calculation of energies and matrix elements in Li are extended and applied to cesium. We employ a relativistic, linearized, coupled-cluster formalism, incorporating single, double, and an important subset of triple excitations. A coupled-cluster formulation of the matrix element of a one-body operator, incorporating the random-phase approximation exactly, is used to calculate hyperfine constants and transition-matrix elements. We find agreement with experiment at the 0.5% level or better for ionization energies and dipole-matrix elements, and at the 1% level for hyperfine constants. Modifications of the method that have the potential of higher accuracy are discussed.

Analysis and synthesis of a class of discrete-time neural networks described on hypercubes

Abstract: A qualitative analysis is presented for a class of synchronous discrete-time neural networks defined on hypercubes in the state space. Analysis results are utilized to establish a design procedure for associative memories to be implemented on the present class of neural networks. To demonstrate the storage ability and flexibility of the synthesis procedure, several specific examples are considered. The design procedure has essentially the same desirable features as the results of J. Li et al. (1988, 1989) for continuous-time neural networks. For a given system dimension, networks designed by the present method may have the ability to store more patterns (as asymptotically stable equilibria) than corresponding discrete-time networks designed by other techniques. The design method guarantees the storage of all the desired patterns as asymptotically stable equilibrium points. The present method provides guidelines for reducing the number of spurious states and for estimating the extent of the patterns' domains of attraction. The present results provide a means of implementing neural networks by serial processors and special digital hardware. >

Expression of three recombinant proteins using baculovirus vectors in 23 insect cell lines.

Abstract: Recombinant Autographa california baculoviruses expressing genes for pseudorabies virus glycoprotein (gp50T), human plasminogen (HPg), and beta-galactosidase (beta-gal) were used to infect 23 cell lines or strains. The objectives were to compare amounts of recombinant proteins expressed in the cell lines, compare yields from clones and parent lines, investigate the effects of long-term culture in serum-free medium on production, and determine if some lines yield gp50T with different glycosylation patterns. For HPg, IZD-MB0503 had the highest yield and four other lines (IPLB-TN-R2, IPLB-SF-1254, IPLB-LdEIta, and CM-1) had levels above that of SF-9 cells. For gp50T, four lines (IPLB-HvT1, IPLB-SF21AE, IPLB-SF21AE-15, and IPLB-SF-1254) had higher amounts than SF-9 cells. Some lines yielded gp50T with molecular mass about 1000 daltons larger than that from SF-9 cells, which suggests increased oligosaccharide processing. Equally high levels of beta-gal were expressed in three lines (SF-9, IZD-MB0503, and BCIRL-PX2-HNV3). The major conclusion is that no single cell line produced highest yields for all three recombinant proteins. Four lines were cultured in serum-free medium for 31-34 passages and then infected with the three recombinant viruses. For most cell line-recombinant combinations, the yields in serum-free medium were equal to or better than those in serum-supplemented medium. Medium composition had a much stronger effect on foreign gene expression than on susceptibility of cells to wild-type virus.

Social Integration and Severe Disabilities A Longitudinal Analysis of Child Outcomes

Abstract: The goal of social integration is shared across disciplines and espoused as a universal value in today's society; however, considerable controversy exists regarding the process most likely to result in the attainment of this goal for persons with severe disabilities. Proponents of traditional rehabilitation-remedial models propose delivery of intensive services in segregated environments specially designed to meet individual needs. Conversely, proponents of full-inclusion models maintain that services be provided in the mainstream of school and society. In the current study, the effects of integrated versus segregated schooling upon the educational and social competence of children with severe developmental disabilities were examined across a 2-year time period, using both classroom observation and standardized child-assessment measures. Children in integrated learning environments spent less time with therapists, equal time with special education teachers, more time with teaching assistants, more time wi...

Aedes albopictus in the Americas.

Abstract: Presentation de la biologie de A. albopictus, des donnees sur la genetique de population, sur son potentiel vecteur de maladies et sur sa distribution en Amerique

An introduction to autonomous control systems

Abstract: The functions, characteristics, and benefits of autonomous control are outlined An overview of some relevant research literature in the field of intelligent and autonomous control is given together with references that outline research directions An autonomous control functional architecture for future space vehicles that incorporates the concepts and characteristics described is presented The controller is hierarchical, with an execution level (the lowest level), coordination level (middle level), and management and organization level (highest level) The general characteristics of the overall architecture, including those of the three levels, are explained, and an example to illustrate their functions is given Mathematical models for autonomous systems, including 'logical' discrete event system models, are discussed Some recent results from the areas of planning and expert systems, machine learning, artificial neural networks, and the area restructurable controls are briefly outlined >

Isolation and characterization of the Drosophila retinal degeneration B (rdgB) gene.

Abstract: Retinal degeneration-B (rdgB) mutants of Drosophila melanogaster undergo rapid light-induced retinal degeneration. We conducted a molecular characterization of the rdgB gene to examine the nature of the gene product. Through the isolation and analysis of X-ray-induced rdgB alleles, the cytogenetic position of the gene was determined to be the 12C1 salivary region. Genomic DNA corresponding to this region was isolated by a chromosomal walk. The chromosomal aberrations associated with the three X-ray-induced rdgB alleles were shown to be within a 5-kb genomic region. A single transcription unit was affected by the alleles, identifying it as the rdgB gene. RNA-RNA Northern hybridization indicated the rdgB gene transcribed five mRNAs ranging in size from 3.9 to 9.5 kb. These mRNAs were expressed in adult heads, but not detected in bodies. Analysis of RNA isolated from wild-type and eyes absent heads indicated that rdgB mRNA expression was not restricted to the retina. DNA sequence analysis of the transcription unit revealed an open reading frame capable of encoding a 116-kD transmembrane protein. The deduced protein shows no overall homology to previously described proteins, but has sequences in common with proposed functional domains of Ca(2+)-ATPase.

Asparagine-linked oligosaccharide processing in lepidopteran insect cells. Temporal dependence of the nature of the oligosaccharides assembled on asparagine-289 of recombinant human plasminogen produced in baculovirus vector infected Spodoptera frugiperda (IPLB-SF-21AE) cells.

Abstract: Previous studies from this laboratory have established that lepidopteran insect cells possess the glycosylation machinery needed to assemble N-linked complex-type oligosaccharides on Asn289 of recombinant human plasminogen (r-HPg). In the present paper, we show that the nature of N289-linked glycosylation of [R561E]r-HPg expressed in Spodoptera frugiperda (IPLB-SF-21AE) cells is dependent upon the length of time of infection of the cells with the recombinant baculovirus/HPg-cDNA construct. At the earliest postinfection (p.i.) time period studied, i.e., 0-20 h, virtually all (96%) of the oligosaccharides released with glycopeptidase F from N289 of the expressed r-HPg were of the high-mannose type and comprised nearly the full range of such structures, containing 3-9 mannose units. At a time window of 60-96 h, p.i., essentially all of the oligosaccharides (92% of the total) assembled on N289 of rHPg were of the biantennary, triantennary, and tetraantennary complex classes, with varying extents of outer arm completion. At an intermediate time period window, of 20-60 h, p.i., a mixture of complex-type oligosaccharides, totaling approximately 77% of the glycans, with various levels of branching and outer arm completion, and high-mannose type of oligosaccharides, totaling approximately 23% of the glycans, was assembled on N289 of the r-HPg produced. These studies demonstrate that lepidopteran insect cells contain the glycosyltransferase genes required for assembly of N-linked complex oligosaccharide and that these transferases are utilized under proper conditions. The time dependency of the assembly of complex-type oligosaccharides on r-HPg indicates that an activation of the appropriate glycosyl transferases and/or transferase genes can take place. Thus, one consequence of the infective process with the recombinant baculovirus/HPg-cDNA construct is to alter the normal glycosylation characteristics of insect cells and to allow complex-type oligosaccharide processing to occur.

Long waves on inclined films at high Reynolds number

Abstract: At large Reynolds number (Re > 10), waves on inclined films grow rapidly downstream in both amplitude and wavelength to the extent that linear stability theory cannot adequately describe their velocity–wavenumber relationship. The wavelength increases indefinitely until solitary waves are formed very far downstream. In a recent experiment of Brauner & Maron (1982), this evolution to long waves is observed to occur by successive wavelength doubling. In this analysis, we develop a second-order integral boundary-layer approximation for long waves at intermediate Re of O(e−1), where e is the dimensionless wavenumber scaled with respect to the film thickness. (A second-order theory is needed because it introduces important dissipation terms which allow periodic and solitary waveforms to exist when surface tension is negligible.) After showing that this model can adequately describe infinitesimal waves at inception, we verify the existence of solitary waves and long-wavelength periodic waves near the critical Reynolds number with a weakly nonlinear analysis. These finite-amplitude waves are then numerically continued into the more important high-Re and strongly nonlinear regions. It is shown that the solitary wave speed approaches 1.67 times the Nusselt velocity, and the thickness of the substrate film approaches 0.47 times the Nusselt film thickness at large Re. These results are favourably compared to experimental data of Chu & Dukler (1974, 1975). We also confirm the period-doubling scenario of Brauner & Maron by showing that short finite-amplitude monochromatic waves are unstable to subharmonic instability.

Spin superlattice formation in ZnSe/Zn1-xMnxSe multilayers.

Abstract: We present magneto-optical evidence for the formation of a magnetic-field-induced spin superlattice in modulated ZnSe/${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Se structures In the samples studied, the offsets in both the conduction band and the valence band are very small at zero magnetic field When a magnetic field is applied, the large Zeeman splitting of the ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Se band edges overcomes the zero-field offsets and results in the formation of a spin superlattice in which spin states of both electrons and holes are spatially and periodically separated

Aedes triseriatus (Diptera: Culicidae) and La Crosse virus. IV. Nutritional deprivation of larvae affects the adult barriers to infection and transmission.

Abstract: Groups of Aedes triseriatus (Say) were reared either as nutritionally deprived (two regimens) or well fed (one regimen) throughout larval development, and the vector competence of resulting small, normal, and large females was assessed for La Crosse virus. When fed a high dose of virus (4.6 log10/0.025 ml in Vero cell culture), 90% of small Ae. triseriatus females transmitted La Crosse virus to suckling mice compared with 70% of normal and 42% of large females. Among small females, 100% had disseminated infections as did 86% of normal females, whereas only 69% of large females had disseminated infections. All females had infected mesenterons (midguts). When fed a low dose of virus (2.2 log10/0.025 ml in Vero cell culture) in a second experiment, 15% of small females transmitted compared with 0% of large females; 50% of small females developed disseminated infections compared with 16% of large females. mesenteronal infection occurred in 70% of small but only 32% of large females. Electron microscopy of mesenteronal tissues from large and small females revealed physical differences in the basement membranes (basal laminae). The mesenterons of small females had 3-6 laminae (mean thickness of the basement membrane = 0.14 microns) compared with 9-16 laminae (mean thickness of the basement membrane = 0.24 microns) in large females. These morphological differences indicated that the mesenteronal escape barrier, which accounted for the difference in the percentage of small and large females with disseminated infections, may be, in part, a physical barrier that was modified by nutritional deprivation in the larval instars.