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Process Theory (process + theory)
Selected AbstractsVisual P3 amplitude and self-reported psychopathic personality traits: Frontal reduction is associated with self-centered impulsivityPSYCHOPHYSIOLOGY, Issue 1 2009Scott R. Carlson Abstract Past studies have examined P3 amplitude as an index of cognitive function related to psychopathy with mixed results. Psychopathy is a heterogeneous set of dissociable traits, and no previous study has examined relationships between P3 and specific traits. A Two Process Theory (TPT) of psychopathy has recently been advanced predicting that P3 reductions are related to only one dimension. We evaluated the relationship between P3 and the two factors of the Psychopathic Personality Inventory (PPI) in 96 undergraduates who performed a visual task. One factor of the PPI, Self-Centered Impulsivity, is related to the dimension of the TPT predicted to underlie P3 reduction. Frontal amplitude reduction was uniquely and inversely related to this trait. The other PPI factor, Fearless Dominance, was associated with faster reaction times. Future work on psychopathic personality and P3 should evaluate whether relationships are unique to one personality dimension. [source] Elementary Process Theory: a formal axiomatic system with a potential application as a foundational framework for physics supporting gravitational repulsion of matter and antimatterANNALEN DER PHYSIK, Issue 10 2010M.J.T.F. Cabbolet Abstract Theories of modern physics predict that antimatter having rest mass will be attracted by the earth's gravitational field, but the actual coupling of antimatter with gravitation has not been established experimentally. The purpose of the present research was to identify laws of physics that would govern the universe if antimatter having rest mass would be repúlsed by the earth's gravitational field. As a result, a formalized axiomatic system was developed together with interpretation rules for the terms of the language: the intention is that every theorem of the system yields a true statement about physical reality. Seven non-logical axioms of this axiomatic system form the Elementary Process Theory (EPT): this is then a scheme of elementary principles describing the dynamics of individual processes taking place at supersmall scale. It is demonstrated how gravitational repulsion functions in the universe of the EPT, and some observed particles and processes have been formalized in the framework of the EPT. Incompatibility of Quantum Mechanics (QM) and General Relativity (GR) with the EPT is proven mathematically; to demonstrate applicability to real world problems to which neither QM nor GR applies, the EPT has been applied to a theory of the Planck era of the universe. The main conclusions are that a completely formalized framework for physics has been developed supporting the existence of gravitational repulsion and that the present results give rise to a potentially progressive research program. [source] The effect of computer anxiety on price value trade-off in the on-line environmentPSYCHOLOGY & MARKETING, Issue 6 2003Rajneesh Suri This research adds to the understanding of how consumers' comfort with computers influences their evaluation of prices for goods offered over the Internet. The effect of computer anxiety, under different motivational conditions, on the evaluation of price for a product in an on-line environment was examined with the use of an experimental design. The results indicate that computer anxiety interacts with motivation to influence price perceptions, in a manner consistent with predictions derived from the process theories of attitude formation and change. Specifically, in the high-motivation condition, subjects with a greater level of computer anxiety viewed high price as indicative of higher value than those with less computer anxiety (who evaluated the low price as better value). In the low-motivation condition, both groups linked high price with higher perceived quality than the low price level. © 2003 Wiley Periodicals, Inc. [source] Age differences in dual information-processing modes,,§CANCER, Issue S12 2008Implications for cancer decision making Abstract Age differences in affective/experiential and deliberative processes have important theoretical implications for cancer decision making, as cancer is often a disease of older adulthood. The authors examined evidence for adult age differences in affective and deliberative information processes, reviewed the sparse evidence about age differences in decision making, and introduced how dual process theories and their findings might be applied to cancer decision making. Age-related declines in the efficiency of deliberative processes predict poorer-quality decisions as we age, particularly when decisions are unfamiliar and the information is numeric. However, age-related adaptive processes, including an increased focus on emotional goals and greater experience, can influence decision making and potentially offset age-related declines. A better understanding of the mechanisms that underlie cancer decision processes in our aging population should ultimately allow us to help older adults to better help themselves. Cancer 2008;113(12 suppl):3556,67. © 2008 American Cancer Society. [source] Soil creep and convex-upward velocity profiles: theoretical and experimental investigation of disturbance-driven sediment transport on hillslopesEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2004Joshua J. Roering Abstract The movement of unconsolidated materials near the Earth's surface is often driven by disturbances that occur at a range of spatial and temporal scales. The nature of these disturbances ranges from highly variable, such as tree turnover, to periodic and predictable, such as frost heave or creep. To explore the effect of probabilistic disturbances on surface processes, we formulated a granular creep model with analogy to rate process theory (RPT) used for chemical reactions. According to the theory, individual particles must be energized to a height greater than adjacent particles in order for grain dilation and transport to occur. The height of neighbouring particles (which is akin to activation energy in chemical reactions) varies with slope angle such that energy barriers get smaller in the downslope direction as slopes steepen. When slopes approach the friction-limited angle of repose, the height of energy barriers approaches zero and grains ,ow in the absence of disturbance. An exponential function is used to describe the probability distribution of particle excitation height although alternative distributions are possible. We tested model predictions of granular dynamics in an experimental sandpile. In the sandpile, acoustic energy serves as the disturbance agent such that grains dilate and shear in response. Particle velocities are controlled by the frequency of energy pulses that result in grain displacement. Using tracer particles, we observed a convex-upward velocity pro,le near the surface of the sandpile, consistent with predictions of our RPT-based velocity model. In addition, we depth-integrated the velocity model to predict how ,ux rates vary with inclination of the sandpile and observed non-linear ,ux,gradient curves consistent with model predictions. By varying the acoustic energy level in the experimental sandpile, we documented changes in the rate of grain movement; similar changes in modelled velocities were achieved by varying the exponent of the particle excitation probability distribution. The general agreement between observed and modelled granular behaviour in our simple laboratory sandpile supports the utility of RPT-based methods for modelling transport processes (e.g. soil creep, frost heave, and till deformation), thus enabling us to account for the probabilistic nature of disturbances that liberate sediment in natural landscapes. Copyright © 2004 John Wiley & Sons, Ltd. [source] Reproduction of temporal scaling by a rectangular pulses rainfall modelHYDROLOGICAL PROCESSES, Issue 3 2002Jonas Olsson Abstract The presence of scaling statistical properties in temporal rainfall has been well established in many empirical investigations during the latest decade. These properties have more and more come to be regarded as a fundamental feature of the rainfall process. How to best use the scaling properties for applied modelling remains to be assessed, however, particularly in the case of continuous rainfall time-series. One therefore is forced to use conventional time-series modelling, e.g. based on point process theory, which does not explicitly take scaling into account. In light of this, there is a need to investigate the degree to which point-process models are able to ,unintentionally' reproduce the empirical scaling properties. In the present study, four 25-year series of 20-min rainfall intensities observed in Arno River basin, Italy, were investigated. A Neyman,Scott rectangular pulses (NSRP) model was fitted to these series, so enabling the generation of synthetic time-series suitable for investigation. A multifractal scaling behaviour was found to characterize the raw data within a range of time-scales between approximately 20 min and 1 week. The main features of this behaviour were surprisingly well reproduced in the simulated data, although some differences were observed, particularly at small scales below the typical duration of a rain cell. This suggests the possibility of a combined use of the NSRP model and a scaling approach, in order to extend the NSRP range of applicability for simulation purposes. Copyright © 2002 John Wiley & Sons, Ltd. [source] Subsampling the mean of heavy-tailed dependent observationsJOURNAL OF TIME SERIES ANALYSIS, Issue 2 2004Piotr Kokoszka Abstract., We establish the validity of subsampling confidence intervals for the mean of a dependent series with heavy-tailed marginal distributions. Using point process theory, we focus on GARCH-like time series models. We propose a data-dependent method for the optimal block size selection and investigate its performance by means of a simulation study. [source] Exploring the association between board and organizational performance in nonprofit organizationsNONPROFIT MANAGEMENT & LEADERSHIP, Issue 3 2005William A. Brown Note: This study investigated six dimensions of effective board performance, as suggested by Chait, Holland, and Taylor (1991), in relation to three theoretical explanations (agency theory, resource dependency theory, and group/decision process theory) of how board governance activities potentially influence organizational performance. Survey research findings revealed that strategic contributions from the board are more robust in organizations with higher financial performance. In addition, organizations that are judged to be higher performing also reported having high-performing boards across all dimensions. In particular, the interpersonal dimension provided a unique explanation of judgments of organizational performance. [source] Recovering from the psychological impact of intensive care: how constructing a story helpsNURSING IN CRITICAL CARE, Issue 6 2009Susan Lecky Williams ABSTRACT Background: Numerous studies have demonstrated both the risk of post-traumatic stress as a result of intensive care unit (ICU) treatment and the efficacy of successful narrative processing for recovery from psychological trauma. Aim: This article is based on recent doctoral research exploring the impact of unanticipated life threats after admission to hospital. It examines the difficulties ICU patients have with constructing coherent narratives of their illness experience and the significance of those difficulties for psychological recovery from critical illness. Methods: The original research used a qualitative design blending discourse, narrative, and phenomenological approaches guided by hermeneutical sensitivity to the evolving language of narrative processing. Patients chosen from ICU discharge summaries showing a critical life-threatening event after admission to hospital were interviewed soon after discharge from hospital and then again 1 year later. Unstructured interviews explored participant experience of a critical event and its aftermath. Results: This article focuses in particular on one finding from the doctoral research. Unanticipated critical illness presented some patients with difficulties in accomplishing the fundamental human task of constructing a narrative of their experience. Risk factors were observed identifying specific vulnerabilities. The extent to which difficulties were overcome impacted positively on the patient's sense of well-being 1 year after discharge. Conclusions: In order to recover psychologically, some ICU patients need help overcoming obstacles to their ability to construct an adequately coherent narrative of their experience. Relevance to clinical practice: ICU follow-up clinics could gain increased clarity of purpose from this narrative conceptual framework, eventually evaluating and validating benchmarks for assessing psychological recovery in relation to specified dimensions of narrative processing. Practice development informed by narrative process theory could also enhance ICU nursing communication. Since story construction is central to a person's core identity processes, person-centred nursing would also be implicated. [source] Partly Functional Temporal Process Regression with Semiparametric Profile Estimating FunctionsBIOMETRICS, Issue 2 2009Jun Yan Summary Marginal mean models of temporal processes in event time data analysis are gaining more attention for their milder assumptions than the traditional intensity models. Recent work on fully functional temporal process regression (TPR) offers great flexibility by allowing all the regression coefficients to be nonparametrically time varying. The existing estimation procedure, however, prevents successive goodness-of-fit test for covariate coefficients in comparing a sequence of nested models. This article proposes a partly functional TPR model in the line of marginal mean models. Some covariate effects are time independent while others are completely unspecified in time. This class of models is very rich, including the fully functional model and the semiparametric model as special cases. To estimate the parameters, we propose semiparametric profile estimating equations, which are solved via an iterative algorithm, starting at a consistent estimate from a fully functional model in the existing work. No smoothing is needed, in contrast to other varying-coefficient methods. The weak convergence of the resultant estimators are developed using the empirical process theory. Successive tests of time-varying effects and backward model selection procedure can then be carried out. The practical usefulness of the methodology is demonstrated through a simulation study and a real example of recurrent exacerbation among cystic fibrosis patients. [source] Nonparametric Estimation in a Cure Model with Random Cure TimesBIOMETRICS, Issue 1 2001Rebecca A. Betensky Summary. Acute respiratory distress syndrome (ARDS) is a life-threatening acute condition that sometimes follows pneumonia or surgery. Patients who recover and leave the hospital are considered to have been cured at the time they leave the hospital. These data differ from typical data in which cure is a possibility: death times are not observed for patients who are cured and cure times are observed and vary among patients. Here we apply a competing risks model to these data and show it to be equivalent to a mixture model, the more common approach for cure data. Further, we derive an estimator for the variance of the cumulative incidence function from the competing risks model, and thus for the cure rate, based on elementary calculations. We compare our variance estimator to Gray's (1988, Annals of Statistics16, 1140,1154) estimator, which is based on counting process theory. We find our estimator to be slightly more accurate in small samples. We apply these results to data from an ARDS clinical trial. [source] An Activation-Based Model of Sentence Processing as Skilled Memory RetrievalCOGNITIVE SCIENCE - A MULTIDISCIPLINARY JOURNAL, Issue 3 2005Richard L. Lewis Abstract We present a detailed process theory of the moment-by-moment working-memory retrievals and associated control structure that subserve sentence comprehension. The theory is derived from the application of independently motivated principles of memory and cognitive skill to the specialized task of sentence parsing. The resulting theory construes sentence processing as a series of skilled associative memory retrievals modulated by similarity-based interference and fluctuating activation. The cognitive principles are formalized in computational form in the Adaptive Control of Thought,Rational (ACT,R) architecture, and our process model is realized in ACT,R. We present the results of 6 sets of simulations: 5 simulation sets provide quantitative accounts of the effects of length and structural interference on both unambiguous and garden-path structures. A final simulation set provides a graded taxonomy of double center embeddings ranging from relatively easy to extremely difficult. The explanation of center-embedding difficulty is a novel one that derives from the model' complete reliance on discriminating retrieval cues in the absence of an explicit representation of serial order information. All fits were obtained with only 1 free scaling parameter fixed across the simulations; all other parameters were ACT,R defaults. The modeling results support the hypothesis that fluctuating activation and similarity-based interference are the key factors shaping working memory in sentence processing. We contrast the theory and empirical predictions with several related accounts of sentence-processing complexity. [source] Martingale Approach for Moments of Discounted Aggregate ClaimsJOURNAL OF RISK AND INSURANCE, Issue 2 2004Ji-Wook Jang We examine the Laplace transform of the distribution of the shot noise process using the martingale. Applying the piecewise deterministic Markov processes theory and using the relationship between the shot noise process and the accumulated/discounted aggregate claims process, the Laplace transform of the distribution of the accumulated aggregate claims is obtained. Assuming that the claim arrival process follows the Poisson process and claim sizes are assumed to be exponential and mixture of exponential, we derive the explicit expressions of the actuarial net premiums and variances of the discounted aggregate claims, which are the annuities paid continuously. Numerical examples are also provided based on them. [source] |