Self-consciousness and the processing of self-relevant information.

Three experiments were conducted to examine cognitive processes involved in self-conscious behavior. According to Hull and Levy (1979), self-consciousness is associated with processes involved in self-referent encoding. The present studies advance the more specific hypothesis that self-consciousness is involved with the aspect of self-reference associated with the activation of knowledge about the self. Experiment 1 used a self-reference paradigm and found that self-consciousness increased the extent to which a manipulation of accessible self-knowledge influenced self-referent encoding. Experiment 2 used a self-perception paradigm and found that self-consciousness increased the extent to which a manipulation of accessible self-knowledge affected subsequent self-perception. Experiment 3 used a correlational design to demonstrate how cognitive processes associated with self-reference may mediate self-conscious behavior. Individual differences in self-referent encoding were associated with individual differences in self-consciousness; both variables were associated with increased affective reactions to self-relevant feedback; and partialing out individual differences in self-referent encoding eliminated the effects of self-consciousness. These results are discussed in terms of their implications for reconciling various theories of self-consciousness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physician-guided treatment compared with a heparin protocol for deep vein thrombosis

BACKGROUND: Effective heparin therapy, defined by therapeutic prolongation of the activated partial thromboplastin time (APTT), decreases the risk of recurrent venous thromboembolism. Achieving therapeutic prolongation of the APTT within 24 hours of the start of heparin therapy has proved difficult. We hypothesized that a protocol that delivered high initial heparin infusions to patients without identifiable risk for bleeding complications would decrease the time to achieve a therapeutic anticoagulant effect without increasing the incidence of major bleeding complications. METHODS: To test this hypothesis, we studied concurrent patient cohorts. We defined a therapeutic anticoagulant effect (APTT > 55 seconds) to be an APTT more than 1.5 times the upper limit of normal. Twenty patients with acute symptomatic deep vein thrombosis received a 5000-U heparin bolus, followed by 1680 U/h (low risk to bleed) or 1240 U/h (high risk to bleed), adjusted by protocol-directed response to APTT results. Forty-eight patients with deep vein thrombosis were treated by their physicians. The Kaplan-Meier method was used to examine the proportion of patients who achieved an APTT greater than 55 seconds as a function of time. RESULTS: The two study cohorts did not differ with respect to age, weight, or risk factors for venous thromboembolism. Analysis of Kaplan-Meier curves showed that the heparin protocol decreased the time to achieve a therapeutic anticoagulant effect (P = .025). Ten (91%) of 11 patients (95% confidence interval, 59% to 100%) without risks to bleed who were treated by the heparin protocol and 29 (60%) of 48 patients (95% confidence interval, 45% to 74%) not treated by the protocol had an initial therapeutic APTT (P = .006). CONCLUSION: A protocol that delivers higher initial heparin infusions to patients without identifiable risks for bleeding decreases the time needed to achieve therapeutic prolongation of APTT, when compared with nonprotocol physician management.     

Incorporating language syntax in visual text recognition with astatistical model

The use of a statistical language model to improve the performance of an algorithm for recognizing digital images of handwritten or machine-printed text is discussed. A word recognition algorithm first determines a set of words (called a neighborhood) from a lexicon that are visually similar to each input word image. Syntactic classifications for the words and the transition probabilities between those classifications are input to the Viterbi algorithm. The Viterbi algorithm determines the sequence of syntactic classes (the states of an underlying Markov process) for each sentence that have the maximum a posteriori probability, given the observed neighborhoods. The performance of the word recognition algorithm is improved by removing words from neighborhoods with classes that are not included on the estimated state sequence. An experimental application is demonstrated with a neighborhood generation algorithm that produces a number of guesses about the identity of each word in a running text. The use of zero, first and second order transition probabilities and different levels of noise in estimating the neighborhood are explored     

Influence of stress intensity and crack speed on fracture surface topography: mirror to mist to macroscopic bifurcation

The development of roughness on the fracture surfaces of a brittle, glassy, epoxy resin from the mirror-to-mist transition to macroscopic bifurcation has been investigated using optical microscopy, scanning electron microscopy (SEM) and contact and non-contact laser profilometry. Most of the observations were made on specimens fractured in edge-notched tension. In a series of tests the initial crack length was varied to obtain fracture surfaces formed by accelerating and decelerating cracks without macroscopic bifurcation (specimen A) and by cracks which accelerated continuously to macroscopic bifurcation (specimen B). Some observations were made on specimens tested in compact tension to study changes in fracture surface topography associated with crack arrest in stick-slip fracture. There was a close correlation between the topographical detail revealed by the different techniques. In specimen A the roughness increased progressively from the mirror-to-mist transition and reached a maximum before decreasing as the crack decelerated. The topographical features revealed by optical microscopy and SEM were the same for accelerating and decelerating cracks at the same roughness value. In specimen B the roughness increased continuously to macroscopic bifurcation. There was a close similarity between the topographical features at all levels of roughness. A simple model for the basic step involved in roughness formation is presented which involves an element of the crack tip tilting out of the plane of the main crack before stopping (micro-bifurcation). The scale of micro-bifurcation ranged from 3 m in the early stages of mist, when the crack velocity was close to 10% of the shear wave velocity, to the full width of the specimen (6 mm) at macroscopic bifurcation. The micro-bifurcation process develops from crack surface undulations and does not involve micro-crack nucleating ahead of the main crack. It is concluded that the relationships between crack velocity and dynamic stress intensity, and the value of the limiting crack velocity, must be interpreted in terms of micro-mechanical processes at the crack tip which are strongly dependent on specific material characteristics.Emeritus Goldsmiths' Professor Metallurgy, University of Cambridge, U.K.     

Influence of stress intensity and crack speed on fracture surface topography: mirror to mist transition

The transition from very smooth mirror crack growth to the early stages of roughening associated with mist has been investigated using a range of surface topography techniques. The fracture mechanics properties of the brittle, glassy and isotropic epoxy resin used in this work were characterized using compact tension (CT) and double torsion (DT) tests (K _Ic=0.65 MN m^–3/2). In the DT test, the mist to mirror transition occurred over a large section of the test sample and this facilitated examination by optical microscopy, scanning electron microscopy, atomic force microscopy and non-contact laser profilometry. Measurements on Wallner lines and river lines were used to map the crack velocities and directions over the fracture surface. The transition from mist to mirror, for a decelerating crack, occurred at a crack velocity, v _c=0.1 v _t, where v _t is the shear wave velocity. There was a sharp change in roughness at the transition but no discontinuity in the crack deceleration behaviour. Two main topographical features were observed at the transition: firstly, undulations in the mirror region which decreased in amplitude away from the transition for a decelerating crack and, by implication, vice versa; secondly, a progressive decrease in river line density (for a decelerating crack). Detailed atomic force microscope profilometry was used to determine the surface topography associated with these features. The results provide an insight into the development of crack instabilities under dynamic conditions and a basis for interpreting the progressive development of roughness up to macroscopic bifurcation.Emeritus Goldsmiths' Professor of Metallurgy, University of Cambridge, UK.     

An Approximation to Two-Sided Tolerance Limits for Normal Populations

The authors present a means of computing two-sided tolerance limits for normal populations by algebraic formulae. Their method utilizes the Fisher-Cornish approximation to the chi-square quantile and an equation in three coefficients empirically derived. They include an analysis of the errors in the two formulae and suggest methods of incorporating the calculations in computer programs.

The tables of Weissberg and Beatty [6] have been an invaluable aid for the construction of two-sided tolerance limits for normal populations. In this article we present a means of computing these tolerance limits with a high speed computer following the lead of Weissberg and Beatty. Our method avoids the problem of solving integral equations by replacing the integral equations with algebraic formulae which approximate the solution to a reasonable degree of accuracy.     

Bench-scale assessment of combustion toxicity—A critical analysis of current protocols

The toxicity of fire effluents is not a material property but a function of both the material and the fire environment. To be meaningful, it is essential that toxicity results should relate to the end-use fire situation. This paper reviews current fire effluent toxicity tests, their relevance to fire, and the ways of assessing and applying their results to reduce fire hazards. There are a large number of different methods for determination of the toxic potency of fire effluents from materials or products. These different methods yield apparently inconsistent data because they represent different fire scenarios; measure product yields either as a function of material flammability or independent of it; base the toxicity assessment on the concentrations of different species; or use animal exposure to generate an overall estimate of toxic potency without knowledge of the relative contributions of the chemical species.     

Development of fire‐retarded materials—Interpretation of cone calorimeter data

There is little consensus within the fire science community on interpretation of cone calorimeter data, but there is a significant need to screen new flammability modified materials using the cone calorimeter. This article is the result of several discussions aiming to provide guidance in the use and interpretation of cone calorimetry for those directly involved with such measurements. This guidance is essentially empirical, and is not intended to replace the comprehensive scientific studies that already exist. The guidance discusses the fire scenario with respect to applied heat flux, length scale, temperature, ventilation, anaerobic pyrolysis and set‐up represented by the cone calorimeter. The fire properties measured in the cone calorimeter are discussed, including heat release rate and its peak, the mass loss and char yield, effective heat of combustion and combustion efficiency, time to ignition and CO and smoke production together with deduced quantities such as FIGRA and MARHE. Special comments are made on the use of the cone calorimeter relating to sample thickness, textiles, foams and intumescent materials, and the distance of the cone heater from the sample surface. Finally, the relationship between cone calorimetry data and other tests is discussed. Copyright © 2007 John Wiley & Sons, Ltd.