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Results for “Utility Theory”

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PubMed1994

A framework for dynamic assessment in phonology: stimulability revisited.

Research on stimulability is explored and evaluated. Application of the concept of stimulability as a prognostic indicator is suggested for use in the evaluation of children who have phonological disorders. A framework for dynamic assessment, based on Vygotsky's principles and theory, is proposed as having clinical utility for determining a child's potential for learning, identifying factors that may influence the child's learning, and identifying factors that may facilitate the child's development or functioning. Eight factors are identified that may serve as antecedent cues to facilitate a child's learning of a target sound and are presented in an hierarchical order. Systematic manipulation of response complexity, in terms of linguistic complexity and interaction with language components followed by clinician manipulation of consequent events are also suggested. The approach is designed to address clinical questions such as "Who to treat?," "When to treat?," "What to treat?," "How to treat?," and "What prognosis is expected from treatment?"

Articulation Disorders↗

PubMed1997

Classification and acute management of thoracolumbar fractures.

Successful management of traumatic injuries of the thoracolumbar spine requires understanding of the concepts of spinal stability and instability. There are numerous classifications of injury patterns based on fracture type and the probable forces involved. This article focuses on Denis's three-column theory of spinal stability and its utility in categorizing five injury patterns and the forces involved: specifically, wedge compression fractures, burst fractures, flexion distraction injuries, fracture dislocations, and miscellaneous injuries. The authors also highlight the acute management and evaluation of patients suspected to have these types of injuries.

Acute Disease↗

PubMed1997

Reaffirming the relevance of culture for nursing.

This article reaffirms the relevance of the concept of culture for nursing and suggests the utility of recent developments in culture theory. Culture has long been considered to play an important role in the practice of nursing. The historical development of the concept of culture is reviewed with emphasis on nurse scholars and anthropologists who have addressed culture as an area of inquiry. The meaning-centered perspective of culture, to include embodiment, is reviewed and recommended as a means of addressing the current emphasis on cultural diversity in nursing. This perspective is seen as having broad implications for both advancing theoretical development in nursing and for nursing practice.

Culture↗

PubMed1998

Pharmacokinetics of factor VIII in hemophilia A patients assessed by frequency response method.

The frequency response method, having its mathematical underpinnings in the theory of linear dynamic systems, was utilized to model pharmacokinetic systems describing the fate of factor VIII (F VIII) administered to hemophilia A patients before surgery. The pharmacokinetic system was defined on the basis of the patient's data in such a way that the injection of F VIII during 5-15 min was considered the input, and the corresponding plasma F VIII concentration profile consisting of both the injection and post-injection part the output of this system. The approach is an alternative to routine procedures based only on evaluation of the post-injection part of the F VIII concentration profile. With respect to the common sampling schedule of F VIII, simple second-order models were found acceptable for all the patients involved in the study. However, in the patients whose plasma F VIII concentration profiles did not decrease monotonously after the injection, these models failed to approximate secondary peaks indicating the presence of time delays in F VIII kinetics. The results obtained were discussed with respect to applications of pharmacokinetic models for the adjusted dose continuous infusion of F VIII in hemophilia A patients during and after surgical interventions.

Adolescent↗

PubMedDate not supplied

TIMI grade flow, mortality, and the GUSTO-III trial.

Thrombolytic therapy dates back to animal studies performed in the early 1940s, although clinical trials did not begin until the early 1980s. Many large, placebo-controlled trials conclusively recorded improved survival with thrombolytics in the treatment of acute myocardial infarction. However, only recently did clinical trials compare tissue plasminogen activator (tPA) and streptokinase (SK), and only one study showed a difference in mortality between them. This discrepancy, in part, led to the open-artery hypothesis that early and sustained infarct-related artery patency improves outcome. This theory was tested in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) study. The angiographic substudy of GUSTO-I provided strong evidence for the relationship between 90-minute thrombolysis in myocardial infarction (TIMI) grade 3 flow and lower mortality. However, despite significantly higher 90-minute TIMI grade 3 flow (54% vs 32%) with accelerated tPA versus SK plus intravenous heparin, the absolute difference in mortality rate was less than 1%. The recently completed GUSTO-III trial compared accelerated tPA with reteplase (rPA). Based on the open-artery hypothesis and previous data showing an absolute difference of 15% in 90-minute TIMI grade 3 flow between the agents, it was anticipated that mortality would be lower with rPA than with accelerated tPA. The GUSTO-III study showed no significant difference in 30-day mortality for the agents (7.47% vs 7.24%, p=0.61), respectively. These results raise questions about the validity of the hypothesis: if 90-minute TIMI grade 3 flow is such a strong predictor of mortality, why is there not a greater difference in mortality rates for thrombolytic agents?

Coronary Angiography↗

PubMed2004

[Basic research in supporting the family who provides home care for their elderly people who need medical treatment at home--focusing on "uncomfortableness as judged by the utilization of the external human resource"].

The purpose of this study was to examine the use of external resource by the family caring for the elderly people who need medical treatment at home, and to discuss the methods of family support. An interview and the participatory observation were conducted to each of the 16 families, and the data were analyzed based on the Grounded Theory Approach. "Uncomfortableness as judged by the utilization of external resources" was found as a crucial factor to control the utilization of external human resources. The 3 factors that influenced the degree of uncomfortableness were also clarified. Those findings suggest that it is important to reduce the uncomfortableness stemming from the utilization of external support.

Aged↗

PubMed2004

Evaluation of the Mississippi PTSD Scale--Revised using Rasch measurement.

This study used Rasch measurement theory to examine the Mississippi Scale--Revised for its utility in the development of an interval measure of posttraumatic stress disorder (PTSD). Rasch is a probability-based theory that provides both a measure of the person responding to the instrument and the location of each item calibration on one common construct or dimension. The study used a largely male sample of 153 veterans to evaluate the quality of the items defining PTSD, to describe how the items represent the symptom range of the disorder, and to assess the functioning of items in evaluating PTSD with and without comorbid MDD. Sixteen items were found to fit the measurement model. These items may be used to develop an interval scale of the PTSD construct that is generalizable across diverse populations and that can be used for individualized comparable assessments.

Adult↗

PubMed2002

Analysis of vibrational spectra of chlorotoluene based on density function theory calculations.

The conformational behavior and structural stability of chlorotoluene were investigated by utilizing ab initio calculations with 6-31G* basis set at restricted Hartree-Fock (RHF) and density function theory (DFT) levels. The vibrational frequencies of chlorotoluene were computed at the RHF and DFT levels. Complete vibrational assignments were made on the basis of normal coordinate calculations for stable conformer of the molecule. RHF results without scaled quantum mechanical (SQM) force field procedure considered are in bad agreement with experimental values. Of the five DFT methods, BLYP reproduces the observed fundamental frequencies most satisfactorily with the mean absolute deviation of the non-CH stretching modes less than 10 cm(-1). Two hybrid DFT methods are found to yield frequencies, which are generally higher than the observed fundamental frequencies. When the calculated results are compared with 'experimental' frequencies, B3LYP method is found to be slightly more accurate for C-H stretching modes. The results indicate that BLYP calculation is a very promising approach for understanding the observed spectral features.

Benzyl Compounds↗

PubMed2005

An attachment theory perspective on the proposed matrix model.

The matrix model (C.R. Snyder & T.R. Elliott, this issue, pp. 1033-1054) advocates an increased grounding of clinical psychology graduate students in theory. The matrix model is theory-based in the ways that it advances this goal. Accordingly, evaluating the matrix model from an extant theoretical perspective should shed light on its applicability and utility as an educational framework. The present attachment theory perspective on the matrix model demonstrates that it meets its stated goals in that it possesses adequate (a) breadth in incorporating theory from across subdisciplines in psychology, and (b) depth in how it facilitates conceptualizing clients and research participants at the intrapersonal, interpersonal, and societal levels. The benefits for incorporating the matrix model in clinical psychology graduate programs are discussed.

Curriculum↗

PubMed1993

From behavior theory to behavior therapy: the contributions of behavioral theories and research to the advancement of behavior therapy.

As we approach the latter years of the twentieth century, a century that witnessed the birth of the behavior therapy movement, it becomes increasingly important to understand the forces that shaped the development, advancement, and success of behavior therapy. This paper is an introduction to a series of articles analyzing how major behavioral theories and research have contributed to the advancement of behavior therapy. In view of the fact that many behavior therapists have lost touch with the relation between behavior theory and behavior therapy and the challenges of the "cognitive revolution", we argue that the field would benefit conceptually and practically from integrating and utilizing the resources provided by recent advances in basic behavioral theory and research. The articles in this symposium attempt to build conceptual, methodological, and practical bridges to help behavior therapists recognize and utilize basic behavioral research and concepts.

Behavior Therapy↗

PubMed2003

Explaining happiness.

What do social survey data tell us about the determinants of happiness? First, that the psychologists' setpoint model is questionable. Life events in the nonpecuniary domain, such as marriage, divorce, and serious disability, have a lasting effect on happiness, and do not simply deflect the average person temporarily above or below a setpoint given by genetics and personality. Second, mainstream economists' inference that in the pecuniary domain "more is better," based on revealed preference theory, is problematic. An increase in income, and thus in the goods at one's disposal, does not bring with it a lasting increase in happiness because of the negative effect on utility of hedonic adaptation and social comparison. A better theory of happiness builds on the evidence that adaptation and social comparison affect utility less in the nonpecuniary than pecuniary domains. Because individuals fail to anticipate the extent to which adaptation and social comparison undermine expected utility in the pecuniary domain, they allocate an excessive amount of time to pecuniary goals, and shortchange nonpecuniary ends such as family life and health, reducing their happiness. There is need to devise policies that will yield better-informed individual preferences, and thereby increase individual and societal well-being.

Adult↗

PubMed1990

Determination of microvascular oxyhemoglobin saturations using cryospectrophotometry.

Although a four-wavelength method for cryospectrophotometric measurement of intravascular oxyhemoglobin (HbO2) saturations has previously been described, the relationship between experimental measurements and theory has not been clearly detailed. The current work utilizes an empirical relationship between HbO2 saturation measurements and reflected light oximetry, which is consistent with the two-flux theory of Kubelka and Munk (Z. Tech. Phys. 11a: 593-603, 1931). To obtain linear, concentration-independent calibration curves, the theoretical results require that 1) the complex function relating optical density, scattering, and absorption can be linearly approximated over the range of scattering and absorption coefficients used; and 2) the scattering coefficient is independent of wavelength. Incident light cannot easily be measured using reflection spectroscopy, which precludes the determination of isosbestic points. Therefore, equibestic wave-length pairs were used at which optical density differences were invariant with saturation. This allows numerous wavelength sets over the range 540-600 nm to be selected, rather than the limited choices of isosbestic wavelengths. Finally, the effects of freeze rate, freeze depth, Hb concentration, and vessel diameter are each discussed in terms of their influence on experimental measurements.

Animals↗

PubMed1999

Theory of use behind telehealth applications.

A variety of telehealth applications have been implemented throughout the industrialized world. Given that telehealth has yet to become routine in the practices of physicians, the impact of such applications on health care management remains difficult to identify. Only by becoming integrated into the 'normal practice' of clinicians can telehealth facilitate smooth communications in health care delivery processes. In this paper we demonstrate the importance of developing a 'theory of use', describing how clinicians are expected to use teleconsultation in their daily activities. By employing Giddens' Structuration Theory, we can develop a clear vision of the utilization of telehealth, and a better framework with which to assess its added value for health care delivery. We illustrate this claim by referring to our research on the Quebec Inter-Regional Telemedicine Network. In this study we compare the 'theory of use' behind the telemedicine network with the perceptions of physicians regarding their needs in terms of communications and access to expert advice. The breach between the theory and the perceptions of physicians may help to explain how the utilization of telehealth could be enhanced, and how new and sustainable routines for its integration into the health care system might be created.

Diffusion of Innovation↗

PubMed2003

The role of the dielectric barrier in narrow biological channels: a novel composite approach to modeling single-channel currents.

A composite continuum theory for calculating ion current through a protein channel of known structure is proposed, which incorporates information about the channel dynamics. The approach is utilized to predict current through the Gramicidin A ion channel, a narrow pore in which the applicability of conventional continuum theories is questionable. The proposed approach utilizes a modified version of Poisson-Nernst-Planck (PNP) theory, termed Potential-of-Mean-Force-Poisson-Nernst-Planck theory (PMFPNP), to compute ion currents. As in standard PNP, ion permeation is modeled as a continuum drift-diffusion process in a self-consistent electrostatic potential. In PMFPNP, however, information about the dynamic relaxation of the protein and the surrounding medium is incorporated into the model of ion permeation by including the free energy of inserting a single ion into the channel, i.e., the potential of mean force along the permeation pathway. In this way the dynamic flexibility of the channel environment is approximately accounted for. The PMF profile of the ion along the Gramicidin A channel is obtained by combining an equilibrium molecular dynamics (MD) simulation that samples dynamic protein configurations when an ion resides at a particular location in the channel with a continuum electrostatics calculation of the free energy. The diffusion coefficient of a potassium ion within the channel is also calculated using the MD trajectory. Therefore, except for a reasonable choice of dielectric constants, no direct fitting parameters enter into this model. The results of our study reveal that the channel response to the permeating ion produces significant electrostatic stabilization of the ion inside the channel. The dielectric self-energy of the ion remains essentially unchanged in the course of the MD simulation, indicating that no substantial changes in the protein geometry occur as the ion passes through it. Also, the model accounts for the experimentally observed saturation of ion current with increase of the electrolyte concentration, in contrast to the predictions of standard PNP theory.

Cell Membrane Permeability↗

PubMed2004

Robust Bayesian decision theory applied to optimal dosage.

We give a model for constructing an utility function u(theta,d) in a dose prescription problem. theta and d denote respectively the patient state of health and the dose. The construction of u is based on the conditional probabilities of several variables. These probabilities are described by logistic models. Obviously, u is only an approximation of the true utility function and that is why we investigate the sensitivity of the final decision with respect to the utility function. We construct a class of utility functions from u and approximate the set of all Bayes actions associated to that class. Then, we measure the sensitivity as the greatest difference between the expected utilities of two Bayes actions. Finally, we apply these results to weighing up a chemotherapy treatment of lung cancer. This application emphasizes the importance of measuring robustness through the utility of decisions rather than the decisions themselves.

Antineoplastic Agents↗

PubMed2006

Three-class ROC analysis--the equal error utility assumption and the optimality of three-class ROC surface using the ideal observer.

Previously, we have developed a decision model for three-class receiver operating characteristic (ROC) analysis based on decision theory. The proposed decision model maximizes the expected decision utility under the assumption that incorrect decisions have equal utilities under the same hypothesis (equal error utility assumption). This assumption reduced the dimensionality of the "general" three-class ROC analysis and provided a practical figure-of-merit to evaluate the three-class task performance. However, it also limits the generality of the resulting model because the equal error utility assumption will not apply for all clinical three-class decision tasks. The goal of this study was to investigate the optimality of the proposed three-class decision model with respect to several other decision criteria. In particular, besides the maximum expected utility (MEU) criterion used in the previous study, we investigated the maximum-correctness (MC) (or minimum-error), maximum likelihood (ML), and Nyman-Pearson (N-P) criteria. We found that by making assumptions for both MEU and N-P criteria, all decision criteria lead to the previously-proposed three-class decision model. As a result, this model maximizes the expected utility under the equal error utility assumption, maximizes the probability of making correct decisions, satisfies the N-P criterion in the sense that it maximizes the sensitivity of one class given the sensitivities of the other two classes, and the resulting ROC surface contains the maximum likelihood decision operating point. While the proposed three-class ROC analysis model is not optimal in the general sense due to the use of the equal error utility assumption, the range of criteria for which it is optimal increases its applicability for evaluating and comparing a range of diagnostic systems.

Algorithms↗

PubMed1996

Taking quality of life into account in health economic analyses.

Cost-utility analysis is the most commonly used approach to incorporating quality-of-life considerations into economic analyses in health care. This type of analysis produces a ratio of the incremental cost of one intervention over another to the incremental benefit produced, measured in quality-adjusted life years. To be suitable for use in calculating quality-adjusted survival, quality of life must be measured in the form of a utility. Direct utility assessment techniques are grounded in decision analytic theory and are conceptually complex and impractical for use in the clinical trial setting. Alternatives include global rating scale items with appropriate "transformations" and health state classification indices. The first cancer trials to collect economic data and utilities from patients using these techniques are now under way. These trials will serve to answer not only biological questions, but also health policy questions about whether the additional cost of the more expensive therapy is justified by the benefit it produces in both length and quality of life.

Clinical Trials as Topic↗

PubMed2004

[Utilization suitability of forest resources in typical forest zone of Changbai Mountains].

Conservation of natural forest does not simply equal to no logging. The Northeast China Forest Region has a logging quota of mature forest as part of natural forest conservation project. How to determine the logging spots rationally and scientifically is very important. Recent scientific theories of forest resources management advocate that the utilization of forest resources should stick to the principle of sustaining use, and pay attention to the ecological function of forest resources. According to the logging standards, RS and GIS techniques can be used to detect the precise location of forest resources and obtain information of forest areas and types, and thus, provide more rational and scientific support for space choice about future utilization of forest resources. In this paper, the Lushuihe Forest Bureau was selected as a typical case in Changbai Mountains Forest Region to assess the utilization conditions of forest resources, and some advices on spatial choice for future management of forest resources in the study area were offered.

China↗