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Will be medical specialties like sciences in the future? Yes, progressively they will. Accuracy in clinical specialties will be dissimilar in the future because formal-logic mathematics, quantum physics advances and relativity theory utilities. Evidence based medicine is now helping to clinical specialties on scientific accuracy by the way of decision theory.
In this article, we discuss in detail the addition of hydrogen atoms to diacetylene and the reverse dissociation reactions, H + C(4)H(2)<==>i-C(4)H(3) (R1) and H + C(4)H(2)<==>n-C(4)H(3) (R2). The theory utilizes high-level electronic structure methodology to characterize the potential energy surface, Rice-Ramsperger-Kassel-Marcus (RRKM) theory to calculate microcanonical/J-resolved rate coefficients, and a two-dimensional master-equation approach to extract phenomenological (thermal) rate coefficients. Comparison is made with experimental results where they are available. The rate coefficients k1(T, p) and k2(T, p) are cast in forms that can be used in chemical kinetic modeling. In addition, we predict values of the heats of formation of i-C(4)H(3) and n-C(4)H(3) and discuss their importance in flame chemistry. Our basis-set extrapolated, quadratic-configuration-interaction with single and double excitations (and triple excitations added perturbatively), QCISD(T), predictions of these heats of formation at 298 K are 130.8 kcal/mol for n-C(4)H(3) and 119.3 kcal/mol for the i-isomer; multireference CI calculations with a nine-electron, nine-orbital, complete-active-space (CAS) reference wavefunction give just slightly larger values for these parameters. Our results are in good agreement with the recent focal-point analysis of Wheeler et al. (J. Chem. Phys. 2004, 121, 8800-8813), but they differ substantially for DeltaH0(f 298)(n-C(4)H(3)) with the earlier diffusion Monte Carlo predictions of Krokidis et al. (Int. J. Chem. Kinet.2001, 33, 808-820).
BACKGROUND: Providing appropriate and effective information to people with stroke and their families has been identified as a key component to successful practice. Researchers continue to focus on "lack of information" as being the lack of specific technical medical information rather than the communication of practical knowledge and how people use that knowledge to restructure life after stroke. To meet patients' expectations and achieve better outcomes in stroke, professionals need access to communication theory, research, and training. OBJECTIVES: Improve stroke communication systematically. METHOD: This article will examine stroke communication using a three-part framework: 1. Utilize theory to clearly conceptualize how communication influences stroke outcome. 2. Identify components and mechanisms of communication content to positively influence stroke outcome. 3. Develop goals and strategies for putting content skills into stroke communication practice. CONCLUSION: Relatively little is known about the content and structure of informal communication transactions between stroke survivors, families, and health care professionals and how they accommodate (or resist) realignment of identity after stroke. The professional discourse attempts to ensure realistic expectations of recovery whereas stroke survivors and families complain about the negative discourses, how possibilities for life after stroke are presented, and the hopelessness that this creates. More research is required into how these different discourses affect outcomes.
BACKGROUND: Utility theory can be used to quantify dysfunction associated with various diseases and thus can represent a "hard" measure of quality of life. By determining utility values, one can compare the quality of life of patients with ocular disease to that of patients with non-ophthalmic problems. We performed a study to determine whether utility values from patients with ocular disease are associated with clinical variables, including visual acuity in the better-seeing eye, and to develop a mathematical method for converting visual acuity to utility value, if there is an association between the two. METHODS: Cross-sectional study. A total of 239 patients from a tertiary care retinal practice with various ocular conditions, including macular degeneration, cataract, glaucoma and diabetic retinopathy, were interviewed under standardized conditions to determine their utility values by the time trade-off technique. Visual acuity, duration of visual loss and number of concomitant conditions were also determined. Multiple linear regression was performed to determine which variables were associated with utility values. RESULTS: The mean acuity in the better-seeing eye was 0.479 (near 20/40 vision). The mean utility value was 0.72. Accordingly, the average patient in our series was willing to trade 2.8 of every 10 remaining years of life to obtain perfect vision in both eyes. Utility value was significantly associated with visual acuity in the better-seeing eye (F = 69.1, p < 0.001). Other variables were not significantly associated with utility value. The association with duration of visual loss approached statistical significance (p = 0.075). Utility values (U) for patients with ocular disease can be derived from the following formula: U = (0.374)(visual acuity in better-seeing eye) + 0.514. INTERPRETATION: Utility values from patients with ocular disease were strongly associated with visual acuity and could be estimated mathematically.
Six diagnostic methods (Giemsa staining, Ziehl-Neelsen staining, auramine-rhodamine staining, Sheather's sugar flotation, an indirect immunofluorescence procedure, and a modified concentration-sugar flotation method) for the detection of Cryptosporidium spp. in stool specimens were compared on the following attributes: diagnostic yield, cost to perform each test, ease of handling, and ability to process large numbers of specimens for screening purposes by batching. A rank ordering from least desirable to most desirable was then established for each method by using the study attributes. The process of decision analysis with respect to the laboratory diagnosis of cryptosporidiosis is discussed through the application of multiattribute utility theory to the rank ordering of the study criteria. Within a specific health care setting, a diagnostic facility will be able to calculate its own utility scores for our study attributes. Multiattribute evaluation and analysis are potentially powerful tools in the allocation of resources in the laboratory.
Patients with life-threatening conditions sometimes appear to make risky treatment decisions as their condition declines, contradicting the risk-averse behavior predicted by expected utility theory. Prospect theory accommodates such decisions by describing how individuals evaluate outcomes relative to a reference point and how they exhibit risk-seeking behavior over losses relative to that point. The authors show that a patient's reference point for his or her health is a key factor in determining which treatment option the patient selects, and they examine under what circumstances the more risky option is selected. The authors argue that patients' reference points may take time to adjust following a change in diagnosis, with implications for predicting under what circumstances a patient may select experimental or conventional therapies or select no treatment.
OBJECTIVES: This study examined the utility of the theory of planned behaviour (TPB), past behaviour, and spontaneous implementation intentions in predicting exercise behaviour. The psychological correlates of spontaneous implementation intentions and the moderating effects of intention, perceived behavioural control, past behaviour, and implementation intentions at various time points were also examined. DESIGN: Data collection occurred over three phases with a 2- and 3-week interval. The attrition rate was 35.97% leaving a total of 162 participants (63 males, 99 females). In the first wave, participants completed measures of TPB, spontaneous implementation intentions, and past behaviour. Behaviour was assessed in the second and third waves, and a follow-up measure of spontaneous implementation intentions was completed in Phase 3. RESULTS: Several regression analyses were conducted. Attitude towards exercise and perceived behavioural control made a significant contribution to the prediction of intention. Intention made a significant contribution to the prediction of implementation intentions. Spontaneous implementation intentions reduced the effect of intention and past behaviour for behaviour at 2 weeks and when indexed over a 5-week period. When behaviour was measured for a 3-week period (following an initial 2-week period), the variance that intention and past behaviour accounted for in exercise behaviour decreased, and spontaneous implementation intentions were no longer a significant predictor of behaviour. Spontaneous implementation intentions were found to interact with past behaviour, such that implementation intentions predicted exercise behaviour only among participants who did not exercise frequently in the past. CONCLUSIONS: Implications and future research directions are discussed.
We have suggested that certain research challenges now face the profession. In summary, these challenges may be seen as part of the dual mission of research in a practice profession. Research must contribute to the development of a body of knowledge: some research is academic and theoretical in nature and other research helps to sustain and improve clinical practice. In either case, theory in a practice profession differs significantly from that in more traditional sciences. It is, in fact, more sophisticated and complex than the theory utilized by nonpractice professions, because it must provide the means to state intended outcomes and identify the methods required to achieve the prescribed results (5). This is known as "prescriptive theory" and represents the ultimate research challenge to the practice profession. Prescriptive theory cannot rest on studying what is and what has been; it must anticipate what might be--indeed, what must be--if patients are to achieve their greatest potential as functional members of society.
This paper presents an argument for the existence of "regret' influencing the valuation of alternative outcomes when making treatment decisions in healthcare. It is argued that valuation techniques as currently formulated rely upon the axioms of Expected Utility Theory (transitivity and independence). This potentially leads to a misrepresentation of the respondents true preferences over treatment alternatives, and thus results in the potential for "irrational' decisions being observed. A modified version of Regret Theory is outlined, and the results of a tentative empirical analysis provided to illustrate the importance of accounting for regret in the valuation of health states. It is concluded that regret is an important element in individual valuation and decision making in health care.
The 15D is a generic, comprehensive, 15-dimensional, standardized, self-administered measure of health-related quality of life (HRQoL) that can be used both as a profile and single index score measure. This paper examines the acceptability, reliability, validity, discriminatory power and responsiveness to change of its health state descriptive system and valuation system and presents some examples of applications. As a profile measure on roughly comparable dimensions the 15D performs equally well as the Nottingham Health Profile (NHP) and SF-20, in some respects even better, and clearly better than EQ-5D. The remaining nine to ten dimensions of the 15D provide a large reserve in terms of discriminatory power and responsiveness to change. The valuation system is based on an application of the multiattribute utility theory. The single index score (15D score) on a 0-1 scale, representing the overall HRQoL, is calculated from the health state descriptive system by using a set of population-based preference or utility weights. The 15D scores are shown to be highly reliable, sensitive and responsive to change, generalisable at least in Western-type societies, and particularly valid for deriving quality-adjusted life years (QALYs) gained for resource allocation purposes. The instrument is recommended by the Washington Panel and is available in several languages for clinical economic evaluation and population studies.
We have combined ultrasoft pseudopotential density functional theory utilizing plane wave basis with a Poisson-Boltzmann/solvent-accessible surface area (PB/SA) model to calculate the solvation free energy of small neutral organic compounds in water. The solute charge density obtained from density functional theory was directly used in solving the Poisson-Boltzmann equation to obtain the reaction field. The polarized electronic wave function of the solute in the solvent was solved by including the reaction field in the density functional Hamiltonian. The quantum mechanical and Poisson-Boltzmann equations were solved self-consistently until the charge density and reaction field converged. Using the solute charge density directly instead of a point-charge representation permitted asymmetric distortion and spreading out of the electron cloud. Because the electron density could leave the van der Waals surface to penetrate into the high-dielectric solvent, the reaction field generated by this density was generally smaller than that obtained by using the point-charge representation. In applying this model to calculate the solvation free energy of 31 small neutral organic molecules spanning a range of 25 kcal/mol, we obtained a root-mean-square error of only 1.3 kcal/mol if we allowed one adjustable parameter to shift the calculated solvation free energy.
The extreme importance of critical infrastructures to modern society is widely recognized. These infrastructures are complex and interdependent. Protecting the critical infrastructures from terrorism presents an enormous challenge. Recognizing that society cannot afford the costs associated with absolute protection, it is necessary to identify and prioritize the vulnerabilities in these infrastructures. This article presents a methodology for the identification and prioritization of vulnerabilities in infrastructures. We model the infrastructures as interconnected digraphs and employ graph theory to identify the candidate vulnerable scenarios. These scenarios are screened for the susceptibility of their elements to a terrorist attack, and a prioritized list of vulnerabilities is produced. The prioritization methodology is based on multiattribute utility theory. The impact of losing infrastructure services is evaluated using a value tree that reflects the perceptions and values of the decisionmaker and the relevant stakeholders. These results, which are conditional on a specified threat, are provided to the decisionmaker for use in risk management. The methodology is illustrated through the presentation of a portion of the analysis conducted on the campus of the Massachusetts Institute of Technology.
Problems related to the concept of the "cost of a child", more commonly known as the general equivalence scale, are reviewed. The importance of this concept is noted with regard to both theoretical and empirical studies relating to taxation, poverty, income distribution, dietary needs, income maintenance programs, supplementary and child benefits, and other social security payments. "This paper proposes a new methodology for calculating the scale using a framework which is consistent with utility theory and which overcomes the identification problem without having to enforce the arbitrary prior assumptions of recent studies. The proposed method allows easy calculation of not only the basic 'scale' parameter but also how it varies with price and reference utility. [The author illustrates] the usefulness of the procedure by estimating on U.K. budget data at two different levels of aggregation and employing two sets of quite different functional forms. The results are plausible, compare favourably with one another and, hence, confirm the robustness and usefulness of the proposed procedure."
Formal prescriptive models can help patients and clinicians better understand the risks and uncertainties they face and better formulate well-reasoned decisions. Using Bayes rule, the clinician can interpret pedigrees, historical data, physical findings and laboratory data, providing individualized probabilities of various diagnoses and outcomes of pregnancy. With the advent of screening programs for genetic disease, it becomes increasingly important to consider the prior probabilities of disease when interpreting an abnormal screening test result. Decision trees provide a convenient formalism for structuring diagnostic, therapeutic and reproductive decisions; such trees can also enhance communication between clinicians and patients. Utility theory provides a mechanism for patients to understand the choices they face and to communicate their attitudes about potential reproductive outcomes in a manner which encourages the integration of those attitudes into appropriate decisions. Using a decision tree, the relevant probabilities and the patients' utilities, physicians can estimate the relative worth of various medical and reproductive options by calculating the expected utility of each. By performing relevant sensitivity analyses, clinicians and patients can understand the impact of various soft data, including the patients' attitudes toward various health outcomes, on the decision making process. Formal clinical decision analytic models can provide deeper understanding and improved decision making in clinical genetics.
An algorithm for bone remodeling is presented which allows for both a redistribution of density and a continuous change of principal material directions for the orthotropic material properties of bone. It employs a modal analysis to add density for growth and a local effective strain based analysis to redistribute density. General re-distribution functions are presented. The model utilizes theories of cellular solids to relate density and strength. The code predicts the same general density distributions and local orthotropy as observed in reality.
Multi-attribute utility theory (MAUT) provides a way to model decisions involving trade-offs among different aspects or goals of a problem. We used MAUT to model prostate cancer patients' preferences for their own health state and we compared this model to patients' global judgments of health state utility. 57 patients with prostate cancer (mean age = 70) at two Chicago Veterans Administration health clinics were asked to evaluate health states described in terms of five health attributes affected by prostate cancer: pain, mood, sexual function, bladder and bowel function, and fatigue and energy. Each attribute had three levels that were used to form three clinically realistic health state descriptions (A = high, B = moderate, C = low). A fourth personalized health description (P) matched the patient's current health. We first measured patients' preferences using time trade-off (TTO) judgments for the three health states (A, B, and C) and for their own current health state (P). The TTO for the patient's own health state (P) was standardized by comparing it to TTO judgments for states A and C. We next constructed a multi-attribute model using the relative importance of the five attributes. The MAU scores were moderately correlated with the TTO preference judgments for the personalized state (Pearson r = 0.38, N = 57, p < 0.01). Thus, patients' preference judgments are moderately consistent and systematic. MAUT appears to be a potentially feasible method for evaluating preferences of prostate cancer patients and may prove helpful in assisting with patient decision making.
In 3 experiments, choices for hypothetical amounts of future health and money showed that, contrary to normative discounted utility theory, the temporal discount rate, or annual percentage increase in value needed to offset a delay, differed for the 2 domains. Domain independence, defined as the low correlation between health and money discount rates relative to the consistency within each domain, was not due to different utility functions for health and money. Consistent with other research, these results suggest that decision domain affects the cognitive processes used. Despite this domain difference, there were some similarities between the 2 domains. Both health and money decisions revealed that discount rates were larger for short delays, small magnitudes, and gains as compared with losses.
Confidence and accuracy, while often considered to tap the same memory representation, are often found to be only weakly correlated (e.g., Bothwell, Deffenbacher, & Brigham, 1987; Deffenbacher, 1980). There are at least two possible (nonexclusive) reasons for this weak relation. First, it may be simply due to noise of one sort or another; that is, it may come about because of both within- and between-subjects statistical variations that are partially uncorrelated for confidence measures on the one hand and accuracy measures on the other. Second, confidence and accuracy may be uncorrelated because they are based, at least in part, on different memory representations that are affected in different ways by different independent variables. We propose a general theory that is designed to encompass both of these possibilities and, within the context of this theory, we evaluate effects of four variables--degree of rehearsal, study duration, study luminance, and test luminance--in three face recognition experiments. In conjunction with our theory, the results allow us to begin to identify the circumstances under which confidence and accuracy are based on the same versus different sources of information in memory. The results demonstrate the conditions under which subjects are quite poor at monitoring their memory performance, and are used to extend cue utilization theories to the domain of face recognition.