Showing papers by "Ohio State University published in 1994"

Review of particle properties.

Abstract: This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations. For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review). Another new review is on Grand Unified Theories. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.

Relationship between attitudes and evaluative space: A critical review, with emphasis on the separability of positive and negative substrates.

Abstract: Evaluative processes refer to the operations by which organisms discriminate threatening from nurturant environments. Low activation of positive and negative evaluative processes by a stimulus reflects neutrality, whereas high activation of such processes reflects maximal conflict. Attitudes, an important class of manifestations of evaluative processes, have traditionally been conceptualized as falling along a bipolar dimension, and the positive and negative evaluative processes underlying attitudes have been conceptualized as being reciprocally activated, making the bipolar rating scale the measure of choice. Research is reviewed suggesting that this bipolar dimension is insufficient to portray comprehensively positive and negative evaluative processes and that the question is not whether such processes are reciprocally activated but under what conditions they are reciprocally, nonreciprocally, or independently activated

Intellectual Capital and the Birth of U.S. Biotechnology Enterprises

Abstract: The number of American firms actively using biotechnology grew rapidly from nonexistent to over 700 in less than two decades, transforming the nature of the pharmaceutical industry and significantly impacting food processing, brewing, and agriculture, as well as other industries. Here we demonstrate empirically that the commercialization of this technology is essentially intertwined with the development of the underlying science in a way which illustrates the significance in practice of the localized spillovers concept in the agglomeration literature and of the tacit knowledge concept in the information literature. Indeed we present here strong evidence that the timing and location of initial usage by both new dedicated biotechnology firms ("entrants") and new biotech subunits of existing firms ( "incumbents ") are primarily explained by the presence at a particular time and place of scientists who are actively contributing to the basic science as represented by publications reporting genetic-sequence discoveries in academic journals. By quantifying separable effects of individual scientists, major universities, and federal research support we provide specific structure to the role of universities and their faculties in encouraging local economic development

Organic and Organometallic Molecular Magnetic Materials—Designer Magnets

Abstract: Magnets composed of molecular species or polymers and prepared by relatively low-temperature organic synthetic methodologies are a focus of contemporary materials science research. The anticipated properties of such molecular-species-based magnetic materials, particularly in combination with other properties associated with molecules and polymers, may enable their use in future generations of electronic, magnetic, and/or photonic/photronic devices ranging from information storage and magnetic imaging to static and low-frequency magnetic shielding. A tutorial of typical magnetic behavior of molecular materials is presented. The three distinct models (intramolecular spin coupling through orthogonal orbitals in the same spatial region within a molecule/ion, intermolecular spin coupling through pairwise “configuration interaction” between spin-containing moieties, and dipole—dipole, through-space interactions) which enable the design of new molecular-based magnetic materials are discussed. To achieve the required spin couplings for bulk ferro- or ferrimagnetic behavior it is crucial to prepare materials with the necessary primary, secondary, and tertiary structures akin to proteins. Selected results from the worldwide effort aimed at preparing molecular-based magnetic materials by these mechanisms are described. Some organometallic solids comprised of linear chains of alternating metallocenium donors (D) and cyanocarbon acceptors (A) that is, …D•+ A•− D•+ A•−…, exhibit cooperative magnetic phenomena. Bulk ferromagnetic behavior was first observed below the critical (Curie) temperature Tc of 4.8 K for [FeIII(C5Me5)2]•+ [TCNE]•− (Me = methyl; TCNE = tetracyanoethylene). Replacement of FeIII with MnIII leads to a ferromagnet with a Tc of 8.8 K in agreement with mean-field models developed for this class of materials. Replacement with CrIII, however, leads to a ferromagnet with a Tc lowered to 3.65 K which is at variance with this model. Extension to the reaction of a vanadium(o) complex with TCNE leads to the isolation of a magnet with a Tc ≈ 400 K, which exceeds the thermal decomposition temperature of the material. This demonstrates that a magnetic material with a Tc substantially above room temperature is achievable in a molecule/organic/polymeric material. Finally, a new class of one-dimensional ferrimagnetic materials based on metalloporphins is discussed.

Organizational socialization: Its content and consequences.

Abstract: Content dimensions of the socialization domain were defined in order to determine relationships between learning particular features of a job/organization and the process and outcomes of socialization. Six socialization dimensions-performance proficiency, politics, language, people, organizational goals/values, and history-were supported by a factor analysis on data from 594 full-time professionals. The socialization process was then examined by comparing three groups of respondents who did not change jobs, changed jobs within the organization, or changed jobs and organizations. Results showed these groups had significantly different response patterns on all dimensions

An evolutionary algorithm that constructs recurrent neural networks

Abstract: Standard methods for simultaneously inducing the structure and weights of recurrent neural networks limit every task to an assumed class of architectures. Such a simplification is necessary since the interactions between network structure and function are not well understood. Evolutionary computations, which include genetic algorithms and evolutionary programming, are population-based search methods that have shown promise in many similarly complex tasks. This paper argues that genetic algorithms are inappropriate for network acquisition and describes an evolutionary program, called GNARL, that simultaneously acquires both the structure and weights for recurrent networks. GNARL's empirical acquisition method allows for the emergence of complex behaviors and topologies that are potentially excluded by the artificial architectural constraints imposed in standard network induction methods. >

Pressure swing adsorption

Abstract: A pressure swing adsorption cycle comprised of blowdown, purge, pressurization, feed, pressure equalization and rinse steps provided recovery from an atmospheric air feed, essentially dry and free of carbon dioxide, of a high yield of high purity nitrogen gas and a high yield of a product gas rich in oxygen as well as recovery of a residual feed byproduct gas for recycle with the air feed.

The Classification of the Finite Simple Groups

Abstract: General introduction to the special odd case General lemmas Theorem $C^*_2$: Stage 1 Theorem $C^*_2$: Stage 2 Theorem $C_2$: Stage 3 Theorem $C_2$: Stage 4 Theorem $C_2$: Stage 5 Theorem $C_3$: Stage 1 Theorem $C_3$: Stages 2 and 3 IV$_K$: Preliminary properties of $K$-groups Background references Expository references Glossary Index.

Bankruptcy and Corporate Governance: The Impact of Board Composition and Structure

Abstract: In this study, we examined the relationships among governance structures and corporate bankruptcy. A logistic regression analysis of bankrupt major corporations and a matched group of survivor firm...

How Believing in Ourselves Increases Risk Taking: Perceived Self-Efficacy and Opportunity Recognition

Abstract: What effect does positive and negative feedback about past risk taking have on the future risk taking of decision makers? The results of an experimental study show that subjects who are led to believe they are very competent at decision making see more opportunities in a risky choice and take more risks. Those who are led to believe they are not very competent see more threats and take fewer risks. The feelings of self-competence and self-confidence on one task did not generalize to a similar task. Perception of opportunities was unexpectedly not related to the perception of threats. As executives bring their personal perceptual biases to firm decision making, our results identify a serious built-in bias in SWOT analysis (the analysis of firms' strengths and weaknesses as related to potential opportunities and threats). Executives who believe that they and their firm are very competent will take more risks and vice versa. Our results also provide evidence that the perceived likelihood of an event depends on whether the event is a loss or a gain. Human decision making is subject to the general bias that outcome expectations are not independent of outcome valuations.

Measuring the Affective and Cognitive Properties of Attitudes: Conceptual and Methodological Issues

Abstract: Despite renewed interest in the affective and cognitive properties of attitudes, assessment of these constructs is plagued by a number of problems. Some techniques for overcoming these problems are outlined, and scales for assessing the affective and cognitive properties of attitudes are reported. Two studies examine the reliability and validity of these scales. Study 1 assesses the internal consistency and the discriminant and convergent validity of these scales and indicates that the scales are useful for assessing the affective and cognitive properties of attitudes toward a wide range of objects. In Study 2, the ability of the scales to differentiate attitudes that are based primarily on affective versus cognitive information is examined by experimentally creating affective or cognitive attitudes in subjects. Analyses reveal that the scales can differentiate between people whose attitudes are based primarily on either affective or cognitive information.

Timing of peak bone mass in Caucasian females and its implication for the prevention of osteoporosis. Inference from a cross-sectional model.

Abstract: To determine the timing of peak bone mass and density, we conducted a cross-sectional study of bone mass measurements in 265 premenopausal Caucasian females, aged 8-50 yr Bone mass and bone mineral density were measured using dual X-ray absorptiometry and single-photon absorptiometry at the spine (anteroposterior, lateral), proximal femur, radius shaft, distal forearm, and the whole body Bone mass parameters were analyzed using a quadratic regression model and segmented regression models with quadratic-quadratic or quadratic-linear form The results show that most of the bone mass at multiple skeletal locations will be accumulated by late adolescence This is particularly notable for bone mineral density of the proximal femur and the vertebral body Bone mass of the other regions of interest is either no different in women between the age of 18 yr and the menopause or it is maximal in 50-yr-old women, indicating slow but permanent bone accumulation continuing at some sites up to the time of menopause This gain in bone mass in premenopausal adult women is probably the result of continuous periosteal expansion with age Since rapid skeletal mineral acquisition at all sites occurs relatively early in life, the exogenous factors which might optimize peak bone mass need to be more precisely identified and characterized

Delinquent peers, beliefs, and delinquent behavior: a longitudinal test of interactional theory*

Abstract: Three theoretical models of the interrelations among associations with delinquent peers, delinquent beliefs, and delinquent behavior are examined. The socialization model views delinquent peers and beliefs as causally prior to delinquent behavior, whereas the selection model hypothesizes that associations with delinquent peers and delinquent beliefs are a result of delinquent behavior. The interactional model combines aspects of both the socialization and the selection models, positing that these variables have bidirectional causal influences on one another over time. Data to test for reciprocal causality are drawn from three waves of the Rochester Youth Development Study. Results suggest that simple unidirectional models are inadequate. Associating with delinquent peers leads to increases in delinquency via the reinforcing environment of the peer network. Engaging in delinquency, in turn, leads to increases in associations with delinquent peers. Finally, delinquent beliefs exert lagged effects on peers and behavior, which tend in turn to “harden” the formation of delinquent beliefs.

Wear patterns on retrieved polyethylene tibial inserts and their relationship to technical considerations during total knee arthroplasty.

Abstract: Fifty-five unconstrained polyethylene tibial inserts were retrieved at revision total knee arthroplasty and examined for evidence of wear after a mean implantation time of 34.2 months (2.5-80 months). Twenty inserts were ultra-high molecular weight polyethylene (UHMWPE) and 35 were carbon-reinforced polyethylene. Topographic maps of the articular and metal-backed surfaces of each component were constructed to characterize the extent and location of polyethylene degradation, identified visually by mode. In 32 of the retrieved inserts, pre- and postarthroplasty or prerevision radiographs were analyzed for component positioning, sizing, and extremity alignment. These factors then were compared with the patterns and severity of polyethylene wear on the inserts to establish correlations. Severe generalized articular wear was seen in inserts with third body wear from patellar metal-backed failure and cement debris. Severe localized delamination wear was seen in inserts with rotational-subluxation patterns of wear (p = 0.05). The external rotation subluxation wear pattern was strongly associated with knees that had lateral subluxation of the patella (p = 0.0002). Articular wear and cold flow into screw holes tended to be greater in the tightest prearthroplasty compartment (medial in the varus knee [p = 0.0157]; lateral in the valgus knees [p = 0.0226]). Fourteen of 16 knees with a preoperative varus deformities--even when corrected to a normal postarthroplasty anatomic axis--still had greater medial compartment articular wear (p = 0.001). Twelve of these knees did not have a medial release at the time of initial arthroplasty. Preoperative varus also was found to be related to the occurrence of posteromedial cold flow of polyethylene into tibial tray screw holes (p = 0.007). Increasing tibial insert posterior slope was associated with increasingly posterior articular wear track location (p = 0.03). This study indicates that unconstrained tibial component wear patterns and severity may be associated with clinical and mechanical factors under the surgeon's control, including component size and position, and knee alignment and ligament balance.

Recent progress on regulation of the mitochondrial permeability transition pore; a cyclosporin-sensitive pore in the inner mitochondrial membrane.

Abstract: The mitochondrial permeability transition pore allows solutes with a m.w. ≲1500 to equilibrate across the inner membrane. A closed pore is favored by cyclosporin A acting at a high-affinity site, which may be the matrix space cylophilin isozyme. Early results obtained with cyclosporin A analogs and metabolites support this hypothesis. Inhibition by cyclosporin does not appear to require inhibition of calcineurin activity; however, it may relate to inhibition of cyclophilin peptide bond isomerase activity. The permeability transition pore is strongly regulated by both the membrane potential (Δψ) and ΔpH components of the mitochondrial protonmotive force. A voltage sensor which is influenced by the disulfide/sulhydryl state of vicinal sulfhydryls is proposed to render pore opening sensitive to Δψ. Early results indicate that this sensor is also responsive to membrane surface potential and/or to surface potential gradients. Histidine residues located on the matrix side of the inner membrane render the pore responsive to ΔpH. The pore is also regulated by several ions and metabolites which act at sites that are interactive. There are many analogies between the systems which regulate the permeability transition pore and the NMDA receptor channel. These suggest structural similarities and that the permeability transition pore belongs to the family of ligand gated ion channels.

Mood management across affective states : the hedonic contingency hypothesis

Abstract: Mood management in positive and negative moods is relevant to a variety of social phenomena and has been especially important in the helping literature. Theorists have predicted that sad people strategically engage in mood management activities more than happy people. However, application of learning principles across affective states led the authors to hypothesize that hedonic rewards are more contingent on scrutiny of hedonic consequences in happy than sad states. Thus, happy people should scrutinize the hedonic consequences of potential behaviors more than sad people. A selective exposure paradigm was used to test this hedonic contingency hypothesis. People in whom happy, sad, or neutral states were induced were asked to choose activities in which to engage. In 3 experiments, happy people based their choices on the affective consequences of those activities more than sad or neutral individuals. Implications for interpreting past work are discussed.

Opacities for stellar envelopes

Abstract: We define stellar envelopes to be those regions of stellar interiors in which atoms exist and are not markedly perturbed by the plasma environment. Availability of accurate and extensive atomic data is a prime requirement for the calculation of envelope opacities. For envelopes we adopt the criterion of mass density ρ≤0.01 g cm −3 . We present radiative Rosseland mean opacities for envelopes obtained using atomic data calculated in an international collaboration referred to as the Opacity Project, or OP. Equations of state are calculated using an occupation-probability formalism. To a good approximation, ionization equilibria and level populations in envelopes depend only on the temperature T and electron density N e and are insensitive to chemical mixtures

Asset Sales, Firm Performance, and the Agency Costs of Managerial Discretion

Abstract: We argue that management sells assets when doing so provides the cheapest funds to pursue its objectives rather than for operating efficiency reasons alone This hypothesis suggests that (1) firms selling assets have high leverage and/or poor performance, (2) a successful asset sale is good news and (3) the stock market discounts asset sale proceeds retained by the selling firm In support of this hypothesis, we find that the typical firm in our sample performs poorly before the sale and that the average stock-price reaction to asset sales is positive only when the proceeds are paid out

The Sleep Disorders Questionnaire I: Creation and Multivariate Structure of SDQ

Abstract: The development of the Sleep Disorders Questionnaire (SDQ) from the Sleep Questionnaire and Assessment of Wakefulness (SQAW) of Stanford University is described in detail. The extraction of the best question items from the SQAW and their subsequent rewording in the SDQ to insure greater completion rates are described. Two item test-retest reliability studies are reported on 71 controls and on 130 sleep-disorder patients, which confirmed adequate reliability. To create multivariate scoring scales, SDQ was then given in a multicenter study to 519 persons, 435 of whom were sleep-disorder patients with full polysomnography. Canonical Discriminant Function Analysis was employed, which resulted in four clinical-diagnostic scales: SA for sleep apnea, NAR for narcolepsy, PSY for psychiatric sleep disorder and PLM for periodic limb movement disorder. Each was adjusted for male and female responses and transformed to a percentile using the observed distribution of raw scores. Using Receiver Operating Characteristics analysis, cutoff points were determined for each scale to maximize its sensitivity and specificity. Positive and negative predictive values were also calculated. The SA and NAR scales proved to be the most discriminating.

Machine Learning: Neural Networks, Genetic Algorithms, and Fuzzy Systems

Abstract: Perceptron Learning with a Hidden Layer An Object-Oriented Backpropagation Learning Model Concurrent Backpropagation Learning Algorithms An Adaptive Conjugate Gradient Learning Algorithm for Efficient Training of Neural Networks A Concurrent Adaptive Conjugate Gradient Learning Algorithm on MIMD Shared Memory Machines A Concurrent Genetic/Neural Network Learning Algorithm for MIMD Shared Memory Machines A Hybrid Learning Algorithm for Distributed Memory Multicomputers A Fuzzy Neural Network Learning Model Appendices References Index.