Showing papers by "University of Virginia published in 1989"

Contingency, Irony, and Solidarity

Abstract: In this 1989 book Rorty argues that thinkers such as Nietzsche, Freud, and Wittgenstein have enabled societies to see themselves as historical contingencies, rather than as expressions of underlying, ahistorical human nature or as realizations of suprahistorical goals This ironic perspective on the human condition is valuable on a private level, although it cannot advance the social or political goals of liberalism In fact Rorty believes that it is literature not philosophy that can do this, by promoting a genuine sense of human solidarity A truly liberal culture, acutely aware of its own historical contingency, would fuse the private, individual freedom of the ironic, philosophical perspective with the public project of human solidarity as it is engendered through the insights and sensibilities of great writers The book has a characteristically wide range of reference from philosophy through social theory to literary criticism It confirms Rorty's status as a uniquely subtle theorist, whose writing will prove absorbing to academic and nonacademic readers alike

Generation and Application of Data on Biological Variation in Clinical Chemistry

Abstract: Most clinical chemical analytes vary in a random manner around a homeostatic set point. Replicate analyses of a series of specimens collected from a group of subjects allows estimation of analytical, within and between subject components of variation. The preferred experimental procedures and statistical methods for evaluation of data and analysis of variance are described; a detailed example is provided in the Appendix. The many uses of data on biological variation in clinical chemistry are reviewed, including setting analytical goals, deciding the significance of changes in serial results from an individual, evaluating the utility of conventional population-based reference values in patient management, and other applications.

Theory of plastic deformation: - properties of low energy dislocation structures

Abstract: Work-hardening phenomena are based on the very fundamental principles (i) that at the position of every dislocation axis the respective resolved shear stress cannot exceed the friction stress, including the self-stress of bowing dislocations, and (ii) that always that structure forms which among those accessible by the dislocations minimizes stored energy per unit length of dislocation line. Such dislocation structures have been named LEDSs. The corresponding work-hardening theory, the mesh length theory, is applicable to all materials deforming via gliding dislocations and to all types of deformation. Results previously achieved with the mesh length theory are summarized, and a number of new developments are discussed. Depending on the dislocation structures formed, the work-hardening behavior differs. Easily intersecting glide causes dislocation cell structures with almost dislocation-free cell interiors delineated by dislocation rotation boundaries. Pronounced planar glide causes Taylor lattices characterized by local planar order parallel to the one or perhaps two most highly stressed glide plane(s), no systematic lattice rotations, and overall uniform dislocation density. The most widely observed basic features of work hardening are explained in general terms. Specific applications are indicated for layer-type crystals, h.c.p. single crystals, single-crystal and polycrystalline pure f.c.c. metals and α-brass-type alloys, precipitation-hardened materials and steels. Included are the different stages of work hardening, dynamical effects in low temperature plasticity, the general characteristics of grain boundary strengthening and the Hall-Petch relationship. In addition, proposed explanations for (i) glide system interactions in polyslip resulting in microbands and affecting texture formation, and (ii) creep without stress dependence of dislocation density, are discussed.

Alloy models with the embedded-atom method

Abstract: A simple analytic nearest-neighbor embedded-atom-method model developed formonatomic fcc metals has been extended to study alloying. The two-bodypotential between different species of atoms is taken as a function of thetwo-body potentials for the pure metals with a unique form which yields alloymodels with the same invariance to electron density transformations asmonatomic models. With several approximations, all model parameters are givenby experimentally measured physical quantities. The dilute-limit heats ofsolution for all binary alloys of Cu, Ag, Au, Ni, Pd, and Pt have beencalculated, with generally good agreement with available experimental valuesexcept for Pd, for which the calculated values are uniformly too high. Thequalitative relationships between the physical parameters of the solute andsolvent and the heat of solution have been determined.

The Empire of Chance: How Probability Changed Science and Everyday Life

Abstract: The Empire of Chance tells how quantitative ideas of chance transformed the natural and social sciences, as well as daily life over the last three centuries. A continuous narrative connects the earliest application of probability and statistics in gambling and insurance to the most recent forays into law, medicine, polling and baseball. Separate chapters explore the theoretical and methodological impact in biology, physics and psychology. Themes recur - determinism, inference, causality, free will, evidence, the shifting meaning of probability - but in dramatically different disciplinary and historical contexts. In contrast to the literature on the mathematical development of probability and statistics, this book centres on how these technical innovations remade our conceptions of nature, mind and society. Written by an interdisciplinary team of historians and philosophers, this readable, lucid account keeps technical material to an absolute minimum. It is aimed not only at specialists in the history and philosophy of science, but also at the general reader and scholars in other disciplines.

Oligonucleotide n-alkylphosphoramidates

Abstract: Oligonucleotide N-alkylphosphoramidates useful for combatting diseases by biochemical intervention at the RNA and DNA level are disclosed.

Human-computer interaction using eye-gaze input

Abstract: A description is given of Erica, a computer workstation with a unique user interface. The workstation is equipped with imaging hardware and software, which automatically record a digital portrait of the user's eye. From the features of the current portrait, the interface calculates the approximate location of the user's eye-gaze on the computer screen. The computer then executes commands associated with the menu option currently displayed at this screen location. In this way, the user can interact with the computer, run applications software, and manage peripheral devices-all simply by looking at an appropriate sequence of menu options displayed on the screen. The eye-gaze interface technology, its implementation in Erica, and its application as a prosthetic device are described. >

Identification of nonminimum phase systems using higher order statistics

Abstract: A method is presented for identification of linear, time-variant, nonminimum phase systems when only output data are available. The input sequence need not be independent, but it must be non-Gaussian, with some special properties described in the test. The authors model a finite-dimensional system as an ARMA (autoregressive moving-average) rational function of known orders, but the special cases of AR, MA, and all-pass models are also considered. To estimate the parameters of their model, the authors utilize both second- and higher-order statistics of the output, which may be contaminated by additive, zero-mean, Gaussian white noise of unknown variance. The parameter estimators obtained are proved, under mild conditions, to be consistent. Simulations verify the performance of the proposed method in the case of relatively low signal-to-noise ratios, and when there is a model-order mismatch. >

Neutron Star Accretion in a Supernova

Abstract: An estimate can be made of the effect of a central mass on an explosion through the study of self-similar blast waves in a medium having an inverse-square-of-r density profile, as is approximately the case in the inner core of the progenitor of SN 1987A; its parameters are such that the nucleon density is substantially constant within the shock front. In SN explosions with a massive envelopes, the core material is decelerated by its interaction with the envelope, and a reverse shock wave propagates back to the center. 42 refs.

Analytic embedded atom method model for bcc metals

Abstract: The requirements for fitting bcc metals within the EAM format are discussed and, for comparative purposes, the EAM format is cast in a normalized form. A general embedding function is defined and an analytic first- and second-neighbor model is presented. The parameters in the model are determined from the cohesive energy, the equilibrium lattice constant, the three elastic constants, and the unrelaxed vacancy formation energy. Increasing the elastic constants, increasing the elastic anisotropy ratio, and decreasing the unrelaxed vacancy formation energy favor stability of a close-packed lattice over bcc. A stable bcc lattice relative to close packing is found for nine bcc metals, but this scheme cannot generate a model for Cr because the elastic constants of Cr require a negative curvature of the embedding function.

Tissue Heating During Radiofrequency Catheter Ablation: A Thermodynamic Model and Observations in Isolated Perfused and Superfused Canine Right Ventricular Free Wall

Abstract: The characteristics of radiofrequency catheter ablation induced injury in the heart are not well characterized. Since the mechanism of injury by radiofrequency energy is thermal, this study was performed to determine the temperature gradient in myocardial tissue during radiofrequency (RF) catheter ablation, and to validate a thermodynamic model derived to describe these observations. Lesions were created by RF heating in an experimental model of isolated perfused and superfused canine right ventricular (RV) free wall. RF power output was adjusted to maintain electrode tip temperature at 80 degrees C for 120 seconds in 151 serial lesions and radial temperature gradients were measured. With increasing distance from the electrode, the temperature of the myocardium decreased in a hyperbolic form that was closely predicted by a derived thermodynamic model (P = 0.0001, r = 0.98). This gradient and resultant lesion sizes were unaffected by the rate of coronary perfusion. The utility of tip temperature monitoring as a predictor of lesion size was tested in 104 serial lesions with tip temperatures that were varied between 50 and 85 degrees C. The tip temperature correlated closely with lesion depth (P = 0.0001, r = 0.92) and width (P = 0.0001, r = 0.88), and was a better predictor of lesion size than measurements of power, current or energy. The temperature at the margin between viable and nonviable tissue was estimated to be 47.9 degrees C. These data demonstrate that during radiofrequency catheter ablation, the radial temperature gradient is predictably hyperbolic and appears to be independent of intramyocardial perfusion if constant electrode temperature is maintained. The use of tip temperature monitoring can accurately predict the ultimate size of radiofrequency-induced lesions.

Confirming unexpressed genotypes for schizophrenia: risks in the offspring of Fischer's Danish identical and fraternal discordant twins

Abstract: • Margit Fischer reported in 1971 that the risk of schizophrenia in the offspring of her Danish schizophrenic monozygotic twins and their normal cotwins was equal and not different from the risks in the children of schizophrenics in the literature. All of her identical and fraternal twins who had children and all of their offspring have been followed up through the Danish National Psychiatric Register as of 1985, some 18 years after study by Fischer. The morbid risk (age-corrected) for schizophrenia and schizophrenia-related disorders in the offspring of schizophrenic identical twins is 16.8%; it is 17.4% in their normal cotwins' offspring. The risks in the offspring of schizophrenic fraternal twins and their normal cotwins are 17.4% and 2.1%, respectively. The results suggest that discordance in identical twins may primarily be explained by the capacity of a schizophrenic genotype or diathesis to be unexpressed unless it is released by some kinds of environmental, including nonfamilial, stressors. Sporadic cases and phenocopies caused by cerebral abnormalities, diseases, or viruses would thus be deemphasized as necessary or sufficient explanatory causes for schizophrenia in our study but could account for some of the remaining discordance. Infrequent phenocopies should encourage linkage researchers, but unexpression of genotypes will frustrate them.

A Drosophila tissue polarity locus encodes a protein containing seven potential transmembrane domains

Abstract: The function of the frizzled (fz) locus in Drosophilia melanogaster is required to coordinate the cytoskeletons of epidermal cells to produce a parallel array of cuticular hairs and bristles (for example on the wild-type wing all hairs point towards the distal tip). In fz mutants it is not the structure of individual hairs and bristles that is altered, but their orientation with respect to their neighbours and the organism as a whole. Mitotic clone analysis indicates that fz has two functions in the developing wing. It is required for the proximal-distal transmission of an intercellular polarity signal, a process that is expected to be at least partly extracellular. It is also required for cells to respond to the polarity signal, which is expected to be a cytoplasmic function. The fz locus could encode either one bifunctional or two single-function proteins. We report here that, in pupae, fz produces a messenger RNA that encodes a protein with seven putative transmembrane domains. Thus, the Fz protein should contain both extracellular and cytoplasmic domains, which could function in the transmission and interpretation of polarity information, respectively. This is the first reported sequence for the protein product of a tissue polarity gene.

Evidence that pp42, a major tyrosine kinase target protein, is a mitogen-activated serine/threonine protein kinase.

Abstract: pp42, a low-abundance 42-kDa protein, becomes transiently phosphorylated on tyrosine after stimulation of fibroblasts by a variety of mitogens, including epidermal growth factor, platelet-derived growth factor, phorbol 12-myristate 13-acetate, thrombin, and insulin-like growth factor II. The induction of pp42 phosphorylation on tyrosine by such diverse mitogenic agents suggests an important role for pp42 in the cascade of events necessary for cell transition from G0 into the cell cycle. However, as with most proteins identified on the basis of their tyrosine phosphorylation, the function of pp42 in cellular regulation is unknown. In this manuscript we report evidence that suggests that pp42 is a serine/threonine-specific protein kinase. Stimulation of 3T3-L1 cells with insulin has been shown to activate a cytosolic serine/threonine kinase capable of phosphorylating microtubule-associated protein 2 (MAP-2) and ribosomal protein S6 kinase II. This cytosolic serine/threonine protein kinase, which itself is phosphorylated on tyrosine, has been termed "MAP kinase". We now report that pp42 phosphorylation and MAP kinase activation occur in fibroblasts in response to similar mitogens, that the two proteins comigrate on one- and two-dimensional polyacrylamide gels, and that the two proteins copurify chromatographically. The major peptides generated from purified MAP kinase by V8 protease digestion are present as a subset of the peptides in digests of pp42 excised from two-dimensional gels. Thus, the results suggest that MAP kinase is tyrosine-phosphorylated pp42.

Introspection, attitude change, and attitude-behavior consistency: the disruptive effects of explaining why we feel the way we do

Abstract: Publisher Summary The chapter presents evidence consistent with the observations of Roethke and Vargas Llosa that introspection can be disruptive. The focus is on one type of introspection-thinking—the reasons for one's feelings. The chapter demonstrates that this type of thought can cause people to change their minds about the way they feel and lead to a disconnection between their attitudes and their behavior. It is clear that asking people to think about reasons will often produce attitude change, particularly for affectively based attitudes. The direction of this change, however, has been difficult to predict. The chapter explains people who think about reasons and end up with an attitude that is significantly more negative or positive, on the average, than the attitudes of control subjects. The direction of attitude change is difficult to predict, because it is closely related to the hypothesis about the generation of a biased sample of reasons. In the chapter, there are at least two sorts of harmful attitudes that might be changed by thinking about reasons—those that are undesirable from the individual's perspective and those that are undesirable from a societal perspective.

Emergence and apparent transmission of rimantadine-resistant influenza A virus in families

Abstract: To determine whether rimantadine can protect family members from acquiring influenza A viral illness and to assess the possible selection of drug-resistant strains of virus, we conducted a randomized, double-blind, placebo-controlled study in three communities during two influenza seasons. When influenza A occurred in a family, the members (including the index patient) were given either rimantadine (adult oral dose, 200 mg per day) or placebo for 10 days. The presence of illness was monitored by daily recording of symptoms and temperature measurements; infection was determined by isolation of the virus and by serologic studies. Among households with documented influenza A infections, symptomatic illness occurred in one or more contacts in 10 of 28 families treated with rimantadine and in 10 of 29 families treated with placebo. Asymptomatic secondary influenza A infections were found in five families assigned to receive rimantadine and in four families assigned to receive placebo. Rimantadine-resi...

Recent Developments Concerning Saint-Venant’s Principle: An Update

Abstract: Saint-Venant’s principle plays a central role in the theory and applications of elasticity. A comprehensive review of contemporary research on this topic was given by Horgan and Knowles (1983), and updated by Horgan (1989a). Since these articles were written, several developments in the subject area have taken place. In his second update, we review some of this progress, including a discussion of analogous issues arising in entry flow problems for viscous incompressible fluids.

Marital Transitions: A Child's Perspective.

Abstract: Despite a recent leveling off of the divorce rate, almost half of the children born in the last decade will experience the divorce of their parents, and most of these children will also experience the remarriage of their parents. Most children initially experience their parents' marital rearrangements as stressful; however, children's responses to their parents marital transitions are diverse. Whereas some exhibit remarkable resiliency and in the long term may actually be enhanced by coping with these transitions, others suffer sustained developmental delays or disruptions. Others appear to adapt well in the early stages of family reorganizations but show delayed effects that emerge at a later time, especially in adolescence. The long-term effects are related more to the child's developmental status, sex, and temperament; the qualities of the home and parenting environments; and to the resources and support systems available to the parents and child than they are to divorce or remarriage per se. In recent years, researchers have begun to move away from the view that single-parent and remarried families are atypical or pathogenic families and are focusing on the diversity of children's responses and to the factors that facilitate or disrupt the development and adjustment of children experiencing their parents' marital transitions.

Transformation-specific tyrosine phosphorylation of a novel cellular protein in chicken cells expressing oncogenic variants of the avian cellular src gene.

Abstract: We used myristylated and nonmyristylated c-src-based variants and phosphotyrosine-specific antibodies to reevaluate the role of tyrosine phosphorylation in cellular transformation by pp60src. Prior methods used to detect tyrosine-phosphorylated proteins failed to discriminate predicted differences in tyrosine phosphorylation which are clearly observed with phosphotyrosine-specific antibodies and Western blotting (immunoblotting). Here we report the observation of a 120,000-Mr protein whose phosphorylation on tyrosine correlates with the induction of morphological transformation. p120 was not observed in cells overexpressing the regulated, nononcogenic pp60c-src, whereas phosphorylation of p120 was greatly enhanced in cells expressing activated, oncogenic pp60527F. Furthermore, phosphorylation of p120 was not induced by expression of the activated but nonmyristylated src variant pp602A/527F, which is transformation defective. p120 partitioned preferentially with cellular membranes, consistent with the observation that transforming src proteins are membrane associated. Although a number of additional putative substrates were identified and partially characterized with respect to intracellular localization, tyrosine phosphorylation of these proteins was not tightly linked to transformation.

Place cells and silent cells in the hippocampus of freely-behaving rats

Abstract: In the present study, nearly two-thirds of all hippocampal pyramidal units isolated under barbiturate anesthesia, which maximizes these cell's activity, were behaviorally silent. These "silent cells" showed no spontaneous firing activity in the awake, freely-behaving rat. Both reanesthetization and antidromic stimulation, however, activated these silent cells. More than 92% of the remaining spontaneously active hippocampal pyramidal cells recorded from freely-behaving rats were place cells; i.e., they exhibited spatially specific changes in firing activity in at least one environment. The firing rates of these place cells varied depending on the animal's location in this environment. Interestingly many of these place cells displayed low or no spontaneous activity and no spatial specificity in other, dissimilar environments; i.e., their lack of firing in some spatial environments mirrored the behavioral silence of the more numerous silent cells reported here. In complex information processing, such as the processing of spatial information by the hippocampus demonstrated here, neural silence may be as important a signal as neural activity.

The behavior of sonicated albumin microbubbles within the microcirculation: a basis for their use during myocardial contrast echocardiography.

Abstract: The purpose of this study was to determine whether the behavior of sonicated albumin microbubbles accurately mimics red blood cell flow in the microcirculation and is thus consistent with their use as in vivo tracers of red blood cell flow during myocardial contrast echocardiography. Accordingly, microbubbles prepared from fluorescein-conjugated albumin and fluorescently labeled red blood cells were injected intravascularly in eight golden hamsters. Their intravascular distribution, velocities, arteriolar-to-venular transit and flux ratios at branch points were determined in the microcirculation of the cheek pouch. Albumin microbubbles (mean diameter, 4.9 +/- 3.6 microns) and red blood cells displayed a similar frequency of distribution across the arteriolar lumen (33% in the central 20% of the arterioles), and their arteriolar velocities were also similar (2.5 +/- 0.7 mm/sec and 2.3 +/- 0.7 mm/sec,p = NS). The mean velocities of microbubbles correlated well with those of red blood cells at baseline and after adenosine application (r = 0.97 and r = 0.89, respectively), as did the calculated maximum velocity (r = 0.98 and r = 0.80, baseline and adenosine, respectively). The velocity profiles across the lumen of the vessels for albumin microbubbles and red blood cells were similar at baseline and after adenosine-induced velocity changes. The flux ratios at branch points also correlated well (r = 0.92, p less than 0.001). Arteriolar-to-venular transit times of albumin microbubbles were similar to those of red blood cells in vessels ranging in size from 22 microns to 45 microns. We conclude that the behavior of albumin microbubbles in the microcirculation mimics that of red blood cells and supports their use as intravascular tracers of red blood cell flow during myocardial contrast echocardiography.

Weather and Human Mortality: An Evaluation of Demographic and Interregional Responses in the United States

Abstract: This study describes the impact of weather on human mortality at numerous locations around the United States. We evaluate forty-eight cities and determine the differential impact of weather on mortality on an intercity and interregional level. The mortality data are analyzed separately for different age, race, and cause of death categories. The possible impact of geographical and within-season acclimatization is also analyzed. Thresh-old temperatures, which represent the temperature beyond which mortality increases, are identified for all the categories and all cities in summer and winter. We correlate numerous weather variables with mortality for days with temperatures beyond the threshold. In summer, warm, humid, calm conditions (especially at night) relate to the highest mortality. The strongest relationships occur in regions where hot weather is uncommon and the weakest relationships in the hottest locales. Regional acclimatization appears to be especially important in summer. A strong intra-...

Interleukin-6 stimulates anterior pituitary hormone release in vitro.

Abstract: Interleukin-6 (IL-6), a cytokine produced by inflammatory reactions, was found to stimulate PRL, GH and LH release from anterior pituitary cells at concentrations similar to those which affected lymphocyte mitogenesis. Perifused pituitary cells responded to IL-6 with prompt increases in hormone release that declined rapidly following cessation of exposure. Dopamine (DA) attenuated IL6-induced PRL release. In addition, IL-6 potentiated both GHRF- and TRH-induced hormone release without an affect on intracellular cAMP. These data demonstrate a new biological activity for IL-6 and provide evidence for immune system regulation of anterior pituitary hormone release.