Showing papers by "Cornell University published in 1984"

Toward a Model of Organizations as Interpretation Systems

Abstract: A comparative model of organizations as interpretation systems is proposed. The model describes four interpretation modes: enacting, discovering, undirected viewing, and conditioned viewing. Each mode is determined by (1) management's beliefs about the environment and (2) organizational intrusiveness. Interpretation modes are hypothesized to be associated with organizational differences in environmental scanning, equivocality reduction, strategy, and decision making.

Learning How to Learn

Abstract: For almost a century, educational theory and practice have been influenced by the view of behavioural psychologists that learning is synonymous with behaviour change. In this book, the authors argue for the practical importance of an alternate view, that learning is synonymous with a change in the meaning of experience. They develop their theory of the conceptual nature of knowledge and describe classroom-tested strategies for helping students to construct new and more powerful meanings and to integrate thinking, feeling, and acting. In their research, they have found consistently that standard educational practices that do not lead learners to grasp the meaning of tasks usually fail to give them confidence in their abilities. It is necessary to understand why and how new information is related to what one already knows. All those concerned with the improvement of education will find something of interest in Learning How to Learn.

Boundary Element Techniques: Theory and Applications in Engineering

Abstract: 1 Approximate Methods.- 1.1. Introduction.- 1.2. Basic Definitions.- 1.3. Approximate Solutions.- 1.4. Method of Weighted Residuals.- 1.4.1. The Collocation Method.- 1.4.2. Method of Collocation by Subregions.- 1.5. Method of Galerkin.- 1.6. Weak Formulations.- 1.7. Inverse Problem and Boundary Solutions.- 1.8. Classification of Approximate Methods.- References.- 2 Potential Problems.- 2.1. Introduction.- 2.2. Elements of Potential Theory.- 2.3. Indirect Formulation.- 2.4. Direct Formulation.- 2.5. Boundary Element Method.- 2.6. Two-Dimensional Problems.- 2.6.1. Source Formulation.- 2.7. Poisson Equation.- 2.8. Subregions.- 2.9. Orthotropy and Anisotropy.- 2.10. Infinite Regions.- 2.11. Special Fundamental Solutions.- 2.12. Three-Dimensional Problems.- 2.13. Axisymmetric Problems.- 2.14. Axisymmetric Problems with Arbitrary Boundary Conditions.- 2.15. Nonlinear Materials and Boundary Conditions.- 2.15.1. Nonlinear Boundary Conditions.- References.- 3 Interpolation Functions.- 3.1. Introduction.- 3.2. Linear Elements for Two-Dimensional Problems.- 3.3. Quadratic and Higher-Order Elements.- 3.4. Boundary Elements for Three-Dimensional Problems.- 3.4.1. Quadrilateral Elements.- 3.4.2. Higher-Order Quadrilateral Elements.- 3.4.3. Lagrangian Quadrilateral Elements.- 3.4.4. Triangular Elements.- 3.4.5. Higher-Order Triangular Elements.- 3.5. Three-Dimensional Cell Elements.- 3.5.1. Tetrahedron.- 3.5.2. Cube.- 3.6. Discontinuous Boundary Elements.- 3.7. Order of Interpolation Functions.- References.- 4 Diffusion Problems.- 4.1. Introduction.- 4.2. Laplace Transforms.- 4.3. Coupled Boundary Element - Finite Difference Methods.- 4.4. Time-Dependent Fundamental Solutions.- 4.5. Two-Dimensional Problems.- 4.5.1. Constant Time Interpolation.- 4.5.2. Linear Time Interpolation.- 4.5.3. Quadratic Time Interpolation.- 4.5.4. Space Integration.- 4.6. Time-Marching Schemes.- 4.7. Three-Dimensional Problems.- 4.8. Axisymmetric Problems.- 4.9. Nonlinear Diffusion.- References.- 5 Elastostatics.- 5.1. Introduction to the Theory of Elasticity.- 5.1.1. Initial Stresses or Initial Strains.- 5.2. Fundamental Integral Statement.- 5.2.1. Somigliana Identity.- 5.3. Fundamental Solutions.- 5.4. Stresses at Internal Points.- 5.5. Boundary Integral Equation.- 5.6. Infinite and Semi-Infinite Regions.- 5.7. Numerical Implementation.- 5.8. Boundary Elements.- 5.9. System of Equations.- 5.10. Stresses and Displacements Inside the Body.- 5.11. Stresses on the Boundary.- 5.12. Surface Traction Discontinuities.- 5.13. Two-Dimensional Elasticity.- 5.14. Body Forces.- 5.14.1. Gravitational Loads.- 5.14.2. Centrifugal Load.- 5.14.3. Thermal Loading.- 5.15. Axisymmetric Problems.- 5.15.1. Extension to Nonaxisymmetric Boundary Values.- 5.16. Anisotropy.- References.- 6 Boundary Integral Formulation for Inelastic Problems.- 6.1. Introduction.- 6.2. Inelastic Behavior of Materials.- 6.3. Governing Equations.- 6.4. Boundary Integral Formulation.- 6.5. Internal Stresses.- 6.6. Alternative Boundary Element Formulations.- 6.6.1. Initial Strain.- 6.6.2. Initial Stress.- 6.6.3. Fictitious Tractions and Body Forces.- 6.7. Half-Plane Formulations.- 6.8. Spatial Discretization.- 6.9. Internal Cells.- 6.10. Axisymmetric Case.- References.- 7 Elastoplasticity.- 7.1. Introduction.- 7.2. Some Simple Elastoplastic Relations.- 7.3. Initial Strain: Numerical Solution Technique.- 7.3.1. Examples - Initial Strain Formulation.- 7.4. General Elastoplastic Stress-Strain Relations.- 7.5. Initial Stress: Outline of Solution Techniques.- 7.5.1. Examples: Kelvin Implementation.- 7.5.2. Examples: Half-Plane Implementation.- 7.6. Comparison with Finite Elements.- References.- 8 Other Nonlinear Material Problems.- 8.1. Introduction.- 8.2. Rate-Dependent Constitutive Equations.- 8.3. Solution Technique: Viscoplasticity.- 8.4. Examples: Time-Dependent Problems.- 8.5. No-Tension Materials.- References.- 9 Plate Bending.- 9.1. Introduction.- 9.2. Governing Equations.- 9.3. Integral Equations.- 9.3.1. Other Fundamental Solutions.- 9.4. Applications.- References.- 10 Wave Propagation Problems.- 10.1. Introduction.- 10.2. Three-Dimensional Water Wave Propagation Problems.- 10.3. Vertical Axisymmetric Bodies.- 10.4. Horizontal Cylinders of Arbitrary Section.- 10.5. Vertical Cylinders of Arbitrary Section.- 10.6. Transient Scalar Wave Equation.- 10.7. Three-Dimensional Problems: The Retarded Potential.- 10.8. Two-Dimensional Problems.- References.- 11 Vibrations.- 11.1. Introduction.- 11.2. Governing Equations.- 11.3. Time-Dependent Integral Formulation.- 11.4. Laplace Transform Formulation.- 11.5. Steady-State Elastodynamics.- 11.6. Free Vibrations.- References.- 12 Further Applications in Fluid Mechanics.- 12.1. Introduction.- 12.2. Transient Groundwater Flow.- 12.3. Moving Interface Problems.- 12.4. Axisymmetric Bodies in Cross Flow.- 12.5. Slow Viscous Flow (Stokes Flow).- 12.6. General Viscous Flow.- 12.6.1. Steady Problems.- 12.6.2. Transient Problems.- References.- 13 Coupling of Boundary Elements with Other Methods.- 13.1. Introduction.- 13.2. Coupling of Finite Element and Boundary Element Solutions.- 13.2.1. The Energy Approach.- 13.3. Alternative Approach.- 13.4. Internal Fluid Problems.- 13.4.1. Free-Surface Boundary Condition.- 13.4.2. Extension to Compressible Fluid.- 13.5. Approximate Boundary Elements.- 13.6. Approximate Finite Elements.- References.- 14 Computer Program for Two-Dimensional Elastostatics.- 14.1. Introduction.- 14.2. Main Program and Data Structure.- 14.3. Subroutine INPUT.- 14.4. Subroutine MATRX.- 14.5. Subroutine FUNC.- 14.6. Subroutine SLNPD.- 14.7. Subroutine OUTPT.- 14.8. Subroutine FENC.- 14.9. Examples.- 14.9.1. Square Plate.- 14.9.2. Cylindrical Cavity Problem.- References.- Appendix A Numerical Integration Formulas.- A.1. Introduction.- A.2. Standard Gaussian Quadrature.- A.2.1. One-Dimensional Quadrature.- A.2.2. Two- and Three-Dimensional Quadrature for Rectangles and Rectangular Hexahedra.- A.2.3. Triangular Domain.- A.3. Computation of Singular Integrals.- A.3.1. One-Dimensional Logarithmic Gaussian Quadrature Formulas.- A.3.3. Numerical Evaluation of Cauchy Principal Values.- References.- Appendix B Semi-Infinite Fundamental Solutions.- B.1. Half-Space.- B.2. Half-Plane.- References.- Appendix C Some Particular Expressions for Two-Dimensional Inelastic Problems.

Job Insecurity: Toward Conceptual Clarity

Abstract: A model is presented that summarizes existing knowledge concerning job insecurity, points at its deficiencies, and identifies further research needed to understand the nature, causes, and consequences of this increasingly important phenomenon. Such knowledge is crucial because job insecurity is a key element in a positive feedback loop that accelerates organizational decline.

Method for transporting substances into living cells and tissues and apparatus therefor

Abstract: Inert or biologically active particles are accelerated or propelled at cells at a speed such that the particles can penetrate the surface of the cells and become incorporated into the interior of the cells. The process can be used to mark cells or tissue or to biochemically affect tissues or tissue in situ as well as single cells in vitro. Apparatus for accelerating or propelling the particles toward target cells or tissues are also disclosed. A method for releasing particles adhered to a rotor device is also disclosed.

Modeling the interaction of light between diffuse surfaces

Abstract: A method is described which models the interaction of light between diffusely reflecting surfaces. Current light reflection models used in computer graphics do not account for the object-to-object reflection between diffuse surfaces, and thus incorrectly compute the global illumination effects. The new procedure, based on methods used in thermal engineering, includes the effects of diffuse light sources of finite area, as well as the “color-bleeding” effects which are caused by the diffuse reflections. A simple environment is used to illustrate these simulated effects and is presented with photographs of a physical model. The procedure is applicable to environments composed of ideal diffuse reflectors and can account for direct illumination from a variety of light sources. The resultant surface intensities are independent of observer position, and thus environments can be preprocessed for dynamic sequences.

Small wins: Redefining the scale of social problems.

Abstract: The massive scale on which social problems are conceived precludes innovative action because bounded rationality is exceeded and dysfunctional levels of arousal are induced. Reformulation of social issues as mere problems allows for a strategy of small wins wherein a series of concrete, complete outcomes of moderate importance build a pattern that attracts allies and deters opponents. The strategy of small wins incorporates sound psychology and is sensitive to the pragmatics of policymaking. There is widespread agreement that social science research has done relatively little to solve social problems (Berger, 1976; Cook, 1979; Kohn, 1976). Common to these assessments is the assumption that social science is best suited to generate solutions, when in fact it may be better equipped to address how problems get denned in the first place. A shift of attention away from outcomes toward inputs is not trivial, because the content of appropriate solutions is often implied by the definition of what needs to be solved. To focus on the process of problem definition is to incorporate a more substantial portion of psychology, specifically, its understanding of processes of appraisal, social construction of reality, problem finding, and definition of the situation. Whether social problems are perceived as phenomena that have a serious negative impact on sizable segments of society (Kohn, 1976, p. 94), as substantial discrepancies between widely shared social standards and actual conditions of life (Merton, 1971), or as assertions of grievances or claims with respect to alleged conditions (Spector & Kitsuse, 1977, p. 75), there is agreement that they are big problems. And that's the problem. The massive scale on which social problems are conceived often precludes innovative action because the limits of bounded rationality are exceeded and arousal is raised to dysfunctionally high levels. People often define social problems in ways that overwhelm their ability to do anything about them. To understand this phenomenon, consider the following descriptions of the problems of hunger, crime, heart disease, traffic congestion, and pollution. To reduce domestic hunger we grow more food, which requires greater use of energy for farm equipment, fertilizers, and transportation, adding to the price of energy, which raises the cost of food, putting it out of the price range of the needy. To solve the problem of soaring crime rates, cities expand the enforcement establishment, which draws funds away from other services such as schools, welfare, and job training, which leads to more poverty, addiction, prostitution, and more crime. To ward off coronary heart disease, people who live in cities spend more time jogging and cycling, which exposes their lungs to more air pollution than normal, increasing the risk of coronary illness. To ease traffic congestion, multilane highways are built, which draws people away from mass transit so that the new road soon becomes as overcrowded as the old road. To reduce energy use and pollution, cities invest in mass transit, which raises municipal debt, leading to a reduction in frequency and quality of service and an increase in fares, which reduces ridership, which further raises the municipal debt (Sale, 1980). When social problems are described this way, efforts to convey their gravity disable the very resources of thought and action necessary to change them. When the magnitude of problems is scaled upward in the interest of mobilizing action, the quality of thought and action declines, because processes such as frustration, arousal, and helplessness are activated. Ironically, people often can't solve problems unless they think they aren't problems. If heightened arousal interferes with diagnosis and action, then attacking a less arousing \"mere problem\" should allow attention to be broader and action to be more complex. Responses that are more complex, more recently learned, and more responsive to more stimuli in changing situations usually have a better chance of producing a lasting change in dynamic problems. To recast larger problems into smaller, less arousing problems, people can identify a series of controllable opportunities of modest size that produce visible results and that can be gathered into synoptic solutions. This strategy of small wins addresses social problems by working directly on their construction and indirectly on their resolution. Problems are constructed to stabilize arousal at moderate intensities where its contribution to performance of complex tasks is most beneficial. 40 January 1984 • American Psychologist Copyright 1984 by the American Psychological Association, Inc. Vol. 39, No. I, 40-49 Arousal and Social Problems The following analysis of small wins assumes that arousal varies among people concerned with social problems, but tends to be relatively high, which affects the quality of performance directed at these problems. Arousal is treated as a generic concept under which is assembled a variety of findings that cohere because of their mutual relevance to the Yerkes-Dodson Law (Broadhurst, 1959). Although arousal mechanisms are neither simple nor unidimensional, they do seem to be localized in at least two physiological sites (reticular formation, limbic system), are visible under conditions of sensory deprivation, produce differences in the quality of learning and performance, and have observable physiological effects. The specific effects of arousal on performance associated with the Yerkes-Dodson Law are that (a) there is an inverted-U relationship between arousal and the efficiency of performance with increasing levels of arousal, first improving and then impairing performance and (b) the optimal level of arousal for performance varies inversely with task difficulty. Even though these coarse propositions have been amended, tuned more finely, and differentiated, they remain basic principles in which an analysis of social problem solving can be anchored. Key assertions for the present analysis culled from previous investigations of arousal and performance include the following: 1. Arousal coincides with variation in degrees of activation and varies along at least two dimensions, energy-sleep and tension-placidity (Eysenck, 1982; Thayer, 1978a, 1978b). 2. As arousal increases, attention to cues becomes more selective and this editing is especially detrimental to performance of difficult tasks (Easterbrook, 1959, although this generalization has received mixed support. See Baddeley, 1972; Pearson & Lane, 1983; Weltman, Smith, & Egstrom, 1971, for representative work). 3. At relatively high levels of arousal, coping responses become more primitive in at least three ways (Staw, Sandelands, & Dutton, 1981): (a) people who try to cope with problems often revert to more dominant, first learned actions; (b) patterns of responding that have been learned recently are the first Tom Peters's (1977) original description of small wins was a crucial point of departure for this formulation. Subsequent discussions with Peters, as well as with Linda Pike, Richard Thaler, Joseph McGrath, Sharon McCarthy, David Anderson, Marianne LaFrance, and students and faculty of the Psychology Department at Rice University contributed to my understanding of this phenomenon and I am grateful to all of them for their help. Requests for reprints should be sent to Karl E. Weick, Cornell University, Graduate School of Administration, Malott Hall, Ithaca, New York 14853. ones to disappear, which means that those responses that are most finely tuned to the current environment are the first ones to go; and (c) people treat novel stimuli as if they are more similar to older stimuli than in fact they are, so that clues indicating change are missed. To invert this list, highly aroused people find it difficult to learn a novel response, to brainstorm, to concentrate, to resist old categories, to perform complex responses, to delegate, and to resist information that supports positions they have taken (Holsti, 1978). When these findings are focused on problem solving, they suggest that to call a problem serious is to raise arousal, which is appropriate if people know what to do and have a well-developed response to deal with the problem. This is analogous to the situation of a simple task, the performance of which improves over a considerable range of activation because selective attention does not delete the few cues that are essential for performance. High arousal can improve performance if it occurs after a person has decided what to do and after she or he has overlearned how to do it. To call a problem minor rather than serious is to lower arousal, which is also appropriate if people don't know what to do or are unable to do it. If we assume that most people overlook the fine-grain detail of problems, think only in terms offeree as a response (Nettler, 1980), and overlook minor leverage points from which the problem might be attacked, then it is clear they have neither the diagnoses nor the responses to cope. This means that people need lower arousal to keep diagnostic interference at a minimum and to allow for the practice of relatively complex skills. To keep problem-related arousal at modest intensities, people need to work for small wins. Sometimes problem solving suffers from too little arousal. When people think too much or feel too powerless, issues become depersonalized. This lowers arousal, leading to inactivity or apathetic performance. The prospect of a small win has an immediacy, tangibility, and controllability that could reverse these effects. Alinsky (1972, pp. 114-115) persuaded a demoralized neighborhood group to picket for reinstatement of Infant Medical Care, which he knew would be granted if they merely asked. Organizing for the protest, making the demand, and then receiving what they asked for energized people who had basically given up. Examples of Small Wins Small wins have been designed a

Tonic vasomotor control by the rostral ventrolateral medulla: effect of electrical or chemical stimulation of the area containing C1 adrenaline neurons on arterial pressure, heart rate, and plasma catecholamines and vasopressin

Abstract: We have studied the responses to electrical and chemical stimulation of the ventrolateral medulla in the chloralose-anesthetized, paralyzed, artificially ventilated rat Locations of most active pressor responses were compared to regions containing neurons labeled immunocytochemically for phenylethanolamine N-methyltransferase (PNMT), the enzyme catalyzing the synthesis of adrenaline Elevations of arterial pressure (+816 +/- 25 mm Hg) and cardioacceleration (+73 +/- 136 bpm) were elicited with low current (5 times threshold of 95 +/- 11 microA) electrical stimulation in a region of rostral ventrolateral medullary reticular formation we have termed the nucleus reticularis rostroventrolateralis (RVL) Electrical stimulation of the RVL increased plasma catecholamines (168-fold for adrenaline, 53-fold for noradrenaline, and 19-fold for dopamine) and vasopressin (17-fold before spinal transection, 47-fold after) The location of the most active pressor region in the ventrolateral medulla corresponded closely with the location of C1 adrenaline-synthesizing (PNMT-containing) neurons In addition, the location of the most active pressor region in the dorsomedial medulla corresponded with the location of a bundle of PNMT-containing axons Unilateral injections into the RVL of the excitatory amino acid monosodium L-glutamate (50 pmol to 10 nmol), but not saline, caused transient dose-dependent and topographically specific elevations (maximum +716 +/- 49 mm Hg) of arterial blood pressure and tachycardia Injections of the rigid structural analogue of glutamate, kainic acid, caused large, prolonged (at least 15 min) pressor responses and tachycardia Unilateral injections of the inhibitory amino acid gamma-aminobutyric acid (GABA) into the RVL caused transient dose-dependent hypotension (maximum -408 +/- 66 mm Hg) and bradycardia, whereas the specific GABA antagonist bicuculline caused prolonged (10 to 20 min) elevations (+642 +/- 68 mm Hg) of arterial pressure and tachycardia By contrast, injections of the glycine antagonist strychnine had no significant effect Bilateral injections of the neurotoxin, tetrodotoxin, dropped arterial pressure to low levels (517 +/- 47) not changed by subsequent spinal cord transection at the first cervical segment (525 +/- 62) We propose the following (1) Neurons within the RVL, most probably C1 adrenaline-synthesizing neurons, exert an excitatory influence on sympathetic vasomotor fibers, the adrenal medulla, and the posterior pituitary (2) These neurons are tonically active and under tonic inhibitory control, in part via GABAergic mechanisms--perhaps via the nucleus of the solitary tract (NTS)(ABSTRACT TRUNCATED AT 400 WORDS)

Severe Personality Disorders: Psychotherapeutic Strategies

Abstract: Contents: Preface Acknowledgements Part One: Diagnostic Considerations Part Two: Treatment of Borderline Personalities Part Three: Narcissistic Personalities: Clinical Theory and Treatment Part Four: Severe Regressions: Diagnosis and Treatment Part Five: Hospital Treatment References Index.

Studying Organizational Cultures Through Rites and Ceremonials

Abstract: Studies of organizational culture often focus on discrete cultural forms and fail to place phenomena studied within an overarching conception of culture. Overlap and confusion in terminology occur across studies. To alleviate these problems, this paper offers distinguishing definitions and advocates studying rites and ceremonials, which consolidate multiple cultural forms. The paper also presents, illustrates, and discusses a typology of rites and ceremonials and examines the implications of cultural studies for research and practice.

Energy and the u.s. Economy: a biophysical perspective.

Abstract: A series of hypotheses is presented about the relation of national energy use to national economic activity (both time series and cross-sectional) which offer a different perspective from standard economics for the assessment of historical and current economic events. The analysis incorporates nearly 100 years of time series data and 3 years of cross-sectional data on 87 sectors of the United States economy. Gross national product, labor productivity, and price levels are all correlated closely with various aspects of energy use, and these correlations are improved when corrections are made for energy quality. A large portion of the apparent increase in U.S. energy efficiency has been due to our ability to expand the relative use of high-quality fuels such as petroleum and electricity, and also to relative shifts in fuel use between sectors of the economy. The concept of energy return on investment is introduced as a major driving force in our economy, and data are provided which show a marked decline in energy return on investment for all our principal fuels in recent decades. Future economic growth will depend largely on the net energy yield of alternative fuel sources, and some standard economic models may need to be modified to account for the biophysical constraints on human economic activity.

Walks, walls, wetting, and melting

Abstract: New results concerning the statistics of, in particular,p random walkers on a line whose paths do not cross are reported, extended, and interpreted. A general mechanism yielding phase transitions in one-dimensional or linear systems is recalled and applied to various wetting and melting phenomena in (d=2)-dimensional systems, including fluid films and p×1 commensurate adsorbed phases, in which interfaces and domain walls can be modelled by noncrossing walks. The heuristic concept of an effective force between a walk and a rigid wall, and hence between interfaces and walls and between interfaces, is expounded and applied to wetting in an external field, to the behavior of the two-point correlations of a two-dimensional Ising model belowTc and in a field, and to the character of commensurate-incommensurate transitions ford=2 (recapturing recent results by various workers). Applications of random walk ideas to three-dimensional problems are illustrated in connection with melting in a lipid membrane model.

Milk proteins: physicochemical and functional properties

Abstract: Because of the growing trend toward widespread use of protein ingredients in food formulation and fabrication, an understanding of the relationships between the physical properties of proteins and their behavior in food systems is desirable. A range of milk-derived protein preparations, i.e., dry milk, milk proteins, caseins, whey proteins, and lactalbumin, are used in a range of food products for their specific functional attributes. In this paper some of the apparent relationships between the properties of the protein components and specific functional properties are discussed. Thus, the roles of milk proteins in determining some important physical characteristics (i.e. color, bulk density, sinkability, dispersibility) of milk powders and their involvement in a range of functional properties (water holding, solubility, rheological behavior, gelation, film formation, emulsification, and foaming) are reviewed. Because of the various methods and conditions used in determining functional properties and the variability in composition of preparations it is difficult to compare data and/or reconcile differences in published information. The desirability of developing standard methods is emphasized.

Vortex stability and breakdown - Survey and extension

Abstract: Analyse theorique et experimentale des conditions de stabilite et d'eclatement de tourbillons isoles incompressibles pour des valeurs elevees du nombre de Reynolds. On rappelle des methodes d'experimentation en laboratoire qui ont ete utilisees. On decrit les deux types principaux d'eclatements de tourbillons. On discute de l'importance de la symetrie par rapport a l'axe. On donne un bref apercu de la theorie de l'onde transcritique

Structural path analysis and multiplier decomposition within a social accounting matrix framework

Abstract: The main purpose of this paper is to apply structural path analysis to a Social Accounting Matrix (SAM) framework. Because the SAM is a comprehensive essentially general equilibrium -data system, the whole network through which influence is transmitted can be identified and specified through structural path analysis. The latter provides an alternative and much more detailed way to decompose multipliers as compared with the traditional treatment of Stone (1978) and Pyatt and Round (1979). This paper consists of five sections. The first one reviews the SAM framework as a basis for multiplier analysis and multiplier decomposition. In particular, the additive decomposition in terms of transfer, open-loop and closed-loop effects is succinctly presented. Section II applies this conventional decomposition to a SAM of South-Korea to illustrate with eleven specific cases the effects of an exogenous injection on the endogenous accounts of the SAM, i.e. the incomes, of the factors, household groups and production activities. Section III is devoted to the presentation of the elements of structural analysis and, more particularly, the transmission of economic influence within a structure. Finally, Section IV applies structural path analysis to the South-Korean SAM and compares and contrasts the multiplier decomposition which it yields, with the alternative decomposition discussed in Section II. The comparison is the more significant in that the two decomposition methods are applied to the same eleven selected cases spanning a variety of sectors (i.e. poles) of origin (for the injection) and sectors (poles) of destination. The empirical analysis in Section IV suggests that structural path analysis applied to a SAM is a potentially operationally useful technique within which a whole series of policy issues can be addressed. The final section is devoted to a brief summary and conclusions.

Rostral ventrolateral medulla: selective projections to the thoracic autonomic cell column from the region containing C1 adrenaline neurons.

Abstract: Anterograde, retrograde, and combined axonal transport methods were used to describe the descending efferent projections of a region of rostral ventrolateral medullary reticular formation important in cardiovascular control. We have termed this region, which contains C1 adrenaline-synthesizing neurons, the nucleus reticularis rostroventrolateralis (RVL). Efferent projections from the RVL innervate all segmental levels of the thoracic intermediolateral and intermediomedial columns as shown using retrograde transport of lectin-conjugated horseradish peroxidase (HRP) or fast blue dye, and anterograde transport of either HRP or labeled amino acids. The projection is highly specific in that there are no projections to thoracic dorsal or ventral horns. This innervation corresponds to the distribution of preganglionic sympathetic neurons in the intermediolateral column. In particular, terminals surround neurons projecting to the adrenal medulla, as demonstrated by combined anterograde and retrograde transport methods at the light level. Terminals containing phenylethanolamine-N-methyl transferase (PNMT) were mapped using immunocytochemical techniques. PNMT-labeled terminals were present at all levels of thoracic intermediolateral column, in a distribution similar to that of the descending projections from the RVL. We have previously shown using double label techniques (Ross et al., '81-'83), that many of the spinal projections of the RVL originate from C1 neurons. These data support our suggestion that certain bulbospinal neurons within the RVL, in particular the C1 neurons, are crucial for tonic vasomotor control.

Melting temperature and explosive crystallization of amorphous silicon during pulsed laser irradiation

Abstract: Measurements during pulsed laser irradiation indicate that amorphous Si melts at a temperature 200 \ifmmode\pm\else\textpm\fi{} 50 K below the crystalline value. Below energy densities required to melt the amorphous layer fully, the data are interpreted in terms of an explosive crystallization. The initial liquid layer solidifies to form coarse-grained polycrystalline Si. A thin, self-propagating liquid layer travels through the remaining amorphous Si at a velocity of 10-20 m/s, producing fine-grained polycrystalline Si.

Slip motion and stability of a single degree of freedom elastic system with rate and state dependent friction

Abstract: We consider quasistatic motion and stability of a single degree of freedom elastic system undergoing frictional slip. The system is represented by a block (slider) slipping at speed V and connected by a spring of stiffness k to a point at which motion is enforced at speed V 0 We adopt rate and state dependent frictional constitutive relations for the slider which describe approximately experimental results of Dieterich and Ruina over a range of slip speeds V . In the simplest relation the friction stress depends additively on a term A In V and a state variable θ; the state variable θ evolves, with a characteristic slip distance, to the value − B In V , where the constants A, B are assumed to satisfy B > A > 0. Limited results are presented based on a similar friction law using two state variables. Linearized stability analysis predicts constant slip rate motion at V 0 to change from stable to unstable with a decrease in the spring stiffness k below a critical value k cr . At neutral stability oscillations in slip rate are predicted. A nonlinear analysis of slip motions given here uses the Hopf bifurcation technique, direct determination of phase plane trajectories, Liapunov methods and numerical integration of the equations of motion. Small but finite amplitude limit cycles exist for one value of k , if one state variable is used. With two state variables oscillations exist for a small range of k which undergo period doubling and then lead to apparently chaotic motions as k is decreased. Perturbations from steady sliding are imposed by step changes in the imposed load point motion. Three cases are considered: (1) the load point speed V 0 is suddenly increased; (2) the load point is stopped for some time and then moved again at a constant rate; and (3) the load point displacement suddenly jumps and then stops. In all cases, for all values of k :, sufficiently large perturbations lead to instability. Primary conclusions are: (1) ‘stick-slip’ instability is possible in systems for which steady sliding is stable, and (2) physical manifestation of quasistatic oscillations is sensitive to material properties, stiffness, and the nature and magnitude of load perturbations.

Subcortical efferent projections of the medial geniculate nucleus mediate emotional responses conditioned to acoustic stimuli

Abstract: The purpose of this study was to identify the afferent link in the neural pathway which mediates emotional responses coupled to auditory stimuli We evaluated whether autonomic and behavioral responses elicited by acoustic conditioned emotional stimuli are based on afferent information derived from the auditory cortex or from the auditory thalamic relay station, the medial geniculate nucleus (MG), in rats The rat auditory cortex was defined through anterograde neuroanatomical tracing studies involving the injection of HRP into MG Lesions were then placed in the auditory cortex or in MG After 10 to 20 days the rats were subjected to classical fear conditioning trials involving the pairing of a pure tone with electric footshock Changes in mean arterial pressure and heart rate and the duration of immobilization ("freezing") and drink suppression elicited by presentation during extinction trials (no footshock) of the acoustic conditioned emotional stimulus were measured Auditory cortex lesions did not affect the magnitude of the mean arterial pressure or heart rate conditioned responses nor the duration of freezing or drink suppression In contrast, lesions of MG suppressed the magnitude of both the autonomic and somatomotor (behavioral) conditioned emotional responses but did not affect either autonomic or somatic responses elicited by the footshock unconditioned stimulus Lesions of the inferior colliculus, the primary source of afferent input to MG, replicated the effects of MG lesions These findings demonstrate that lesions of MG and lower auditory centers, but not lesions of the auditory cortex, block autonomic and behavioral conditioned emotional responses coupled to acoustic stimuli and indicate that subcortical rather than cortical efferents of MG sustain these responses Our concurrent observation that MG projects to several subcortical areas (central and lateral amygdala; caudate-putamen; ventromedial hypothalamus) involved in emotional behavior and autonomic function suggests hypotheses concerning subsequent links in this emotional processing pathway

Purification, sequencing and synthesis of natriuretic and vasoactive rat atrial peptide

Abstract: Mammalian atria contain potent natriuretic and diuretic substances1,2 which exist in high- and low-molecular-weight forms2,3 and which appear to be associated with atrium-specific granules4. The natriuretic effect of atrial extract is largely accountable for by its renal haemodynamic effects5–7; atrial extracts also antagonize hormone- and non-hormone-induced contraction of the isolated rabbit aorta8–10 and isolated rat kidney vasculature6. We have completely purified a low-molecular-weight natriuretic and vasoactive substance from rat atria and characterized it as a 24-amino acid peptide. Synthetic peptide, produced by solid-phase synthesis, mimics biological effects of crude atrial extract and purified peptide; its activity is enhanced by slow oxidation, suggesting a disulphide (Cys 4–Cys 20) configuration for the native peptide. If secreted into blood, this atrial natriuretic peptide (‘auriculin B‘) could be a novel peptide hormone of considerable importance to renal and cardiovascular homeostasis.

Intelligence in Schizophrenia: Meta-analysis of the Research

Abstract: This article combines a review and meta-analysis of research on IQ in schizophrenia, with emphasis on areas of convergence in the findings, as well as questions that remain to be answered. Taken together, the findings suggest that early-onset and adult-onset schizophrenia are associated with intellectual deficits across the lifespan. Preschizophrenic children, adolescents, and young adults perform below matched controls on a variety of standardized measures of intelligence. Significant IQ deficits are also apparent after the onset of the disorder. Moreover, IQ is positively related to several indices of prognosis, and, among hospitalized patients, there is negative within-subject covariance between intellectual performance and symptom severity. Although there is fairly consistent evidence that Verbal IQ is higher than Performance IQ among schizophrenic patients, a more specific pattern of subtest performance is not apparent. A central question raised by the results is whether IQ is an independently determined factor that can serve to mitigate the vulnerability of individuals who are constitutionally predisposed to schizophrenia, or whether intellectual deficit is one manifestation of the constitutional predisposition to the disorder. The findings also raise the question of possible sex differences in the developmental determinants of schizophrenia: Meta-analyses revealed that premorbid IQ deficits are more prevalent among males than females.

Improved Computational Methods for Ray Tracing

Abstract: This paper describes algorithmic procedures that have been implemented to reduce the computational expense of producing ray-traced images. The selection of bounding volumes is examined to reduce the computational cost of the ray-intersection test. The use of object coherence, which relies on a hierarchical description of the environment, is then presented. Finally, since the building of the rayintersection trees is such a large portion of the computation, a method using image coherence is described. This visible-surface preprocessing method, which is dependent upon the creation of an "item buffer," takes advantage of a priori image information. Examples that indicate the efficiency of these techniques for a variety of representative environments are presented.

Mutants of S. cerevisiae defective in the maintenance of minichromosomes.

Abstract: We have isolated yeast mutants that are defective in the maintenance of circular minichromosomes. The minichromosomes are mitotically stable plasmids, each of which contains a different ARS (autonomously replicating sequence), a centrometeric sequence, CEN5 , and two yeast genes, LEU2 and URA3 . Forty minichromosome maintenance-defective (Mcm - ) mutants were characterized. They constitute 16 complementation groups. These mutants can be divided into two classes, specific and nonspecific, by their differential ability to maintain minichromosomes with different ARS s. The specific class of mutants is defective only in the maintenance of minichromosomes that carry a particular group of ARS s irrespective of the centromeric sequence present. The nonspecific class of mutants is defective in the maintenance of all minichromosomes tested irrespective of the ARS or centromeric sequence present. The specific class may include mutants that do not initiate DNA replication effectively at specific ARS s present on the minichromosomes; the nonspecific class may include mutants that are affected in the segregation and/or replication of circular plasmids in general.