A method for modeling bias in a person's estimates of likelihoods of events

It is of practical importance in decision situations involving risk to train individuals to transform uncertainties into subjective probability estimates that are both accurate and unbiased. We have found that in decision situations involving risk, people often introduce subjective bias in their estimation of the likelihoods of events depending on whether the possible outcomes are perceived as being good or bad. Until now, however, the successful measurement of individual differences in the magnitude of such biases has not been attempted. In this paper we illustrate a modification of a procedure originally outlined by Davidson, Suppes, and Siegel (3) to allow for a quantitatively-based methodology for simultaneously estimating an individual's subjective utility and subjective probability functions. The procedure is now an interactive computer-based algorithm, DSS, that allows for the measurement of biases in probability estimation by obtaining independent measures of two subjective probability functions (S+ and S-) for winning (i.e., good outcomes) and for losing (i.e., bad outcomes) respectively for each individual, and for different experimental conditions within individuals. The algorithm and some recent empirical data are described

Assessing measurement invariance in questionnaires within latent trait models using item response theory

Using questionnaires or inventories. researchers often perform mean comparisons between different populations (e.g .• males vs. females) in order to draw inferences about actual differences in the constructs being measured. However, such comparisons are not meaningful unless the assessments obtained in each of the populations are conmesurable or invariant across populations. Most researchers simply assume that measuremnt invariance holds. However, the extent to which this assumption is a reasonable one for specific measures and specific populations should be tested empirically. Using item response theory, the present study shows how gender measurement invariance can be determined when. as is most common, a psychological construct is assessed by means of a questionnaire or inventory composed of categorical items. To illustrate our method, the Positive Problem Orientation scale of the Social Problem-Solving Inventory-Revised (D' Zurilla. Nezu & Maydeu-Olivares, 1996) was assessed and found to be reasonably gender invariant. whereas the Negative Problem Orientation scale was not

Developing a measure of blind patients\u27 interactions with their healthcare providers

Background: People who are blind (PWB) are often perceived as being incompetent with common tasks and functions. When patients detect that their healthcare providers (HCPs) have negative perceptions of them, they often report less satisfaction with their healthcare and disengage in their own healthcare. Objective: A scale assessing the experiences of PWB interacting with HCPs was developed and validated across two studies. Methods: In Study 1, 144 participants completed the scale and provided feedback. In Study 2, 214 participants completed the scale and 4 additional scales to assess construct validity. Results: An exploratory factor analysis in Study 1 revealed a two-factor model consisting of General Quality of Health Care (30.5% variance explained) and Stereotype Content-related items (9.4% variance explained). Study 2 confirmed and validated this two-factor structure (RMSEA (90% CI) = 0.068 (0.057, 0.079), CFI = 0.898, SRMR = 0.066, AIC = 14568.902). Conclusions: This scale is one of the first tools developed from the perspectives of PWB. Results from these studies highlight and elaborate on how PWB perceive that they are viewed by their HCPs in terms of competence and how they perceive to be treated by these HCPs. This scale can be used in training HCPs to better serve their patients with disabilities

Efficacy and safety of CO2 insufflation during colonoscopy. Clinical trial

Introduction: Colonoscopy is the technique of choice for the study of colon’s disease and in certain pathologies a therapeutic option. Colon insufflation normally performed using ambient air which led this technique to be painful. Insufflation with carbon dioxide (CO2) causes less abdominal pain.Objective: To evaluate, the efficacy and safety of CO2 insufflation during colonoscopy.Material and Methods: A double-blind randomized controlled trial (Phase IIb) was performed. Universe: all patients with indication of colonoscopies that met the selection criteria and assist to the Minimal Access Surgery National Centre in Havana in the period from October to December 2014. The sample consisted of a total of 100 patients over 18 years of which 50 were subject to the air insufflation technique and 50 with CO2 insufflation. Results: Abdominal pain after colonoscopy was significantly lower in the group that received the CO2 insufflation. Hypoxemia and propofol doses used were similar in both groups. CO2 average pressure values were higher in the case of the CO2 group during the procedure but within the normal range; without clinical complications. Conclusions: The use of CO2 in colonoscopy causes significantly less pain in the first hour. Its use in patients with deep sedation is safe and the technique is not altered and doesn’t have a time reduction. Keywords: Colonoscopy, carbon dioxide, efficacy, safety, clinic trial, abdominal pain, hypoxemia, sedation.</p

Chromatin regulation by Histone H4 acetylation at Lysine 16 during cell death and differentiation in the myeloid compartment

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death

An Investigation of Decomposed and Holistic Judgments in Multiattribute Decision Making: Generalizing the "Divide and Conquer" Principle

273 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.Data is reported that compared the convergent validity (e.g. the agreement between decomposed and holistic strategies), the temporal stability and the external validity (the agreement between a decision strategy and an objective criterion) for decomposed and holistic judgments from two popular multi-criteria decision making techniques, Saaty's (1977, 1980) Analytic Hierarchy Process (AHP) and SMARTS, on a variety of dependent measures. Results indicate that the generality of DAC is indeed dependent upon the choice of the criterion variable.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Important Considerations in Conducting Statistical Mediation Analyses

An investigator wishes to examine mediation in a randomized control trial of the effectiveness of an intervention, which consists of a computerized decision aid for promoting colorectal cancer screening. Mediation is a naturally occurring process, and in any given instance, research investigators seek to ascertain whether it has occurred. In the case of a prevention intervention for a specific chain of events, mediation occurs (1) when the prevention intervention effects a change on a targeted intermediate condition: a mediator, for example, a person’s intentions to get a colorectal screening examination; and (2) when, at a later point in time, this condition effects a change on a targeted outcome, for example, the actual behavior of getting a colorectal screening exam. Full mediation is said to occur when the effectiveness of the intervention on the targeted outcome only takes place through the intermediate condition and does not directly affect the targeted outcome. Partial mediation is said to occur when the intervention causes changes in both the intermediate condition and the targeted outcome. The assessment of mediation is important because conclusions about the efficacy of a public health intervention may depend on how these indirect influences are assessed