Search

Delay discounting describes how a reward loses value as a function of increasing delay to its receipt and has been reliably associated with a variety of vulnerable populations including those with substance use disorders (SUDs). Two commonly used models to assess delay discounting in the field of SUDs include log k derived from Mazur's hyperbolic equation and area under the curve (AUC). In the current study, we compared log k with AUC on delay discounting data obtained from non-treatment seeking, cocaine- and methamphetamine-dependent volunteers. We specifically chose this population in order to obtain a distribution of relatively steep discounters. The results show that the relationship between AUC and log k is better described by a quadratic rather than a linear function. In other words, changes in discounting, as measured by AUC and log k, are reflected differently across a range of obtained responses. Additionally, the distribution of AUC values was skewed, which appears to be more likely among populations exhibiting greater discounting. Finally, closer examination of indifference points revealed that AUC was almost perfectly predicted by the area from the two longest delays, with relatively less input from shorter delays. Given these results, researchers should exercise additional caution when deciding which method to use to assess discounting data and how final results are to be interpreted, particularly when dealing with relatively high rates of discounting. High rates of discounting are likely in populations with impulsive disorders such as those with SUDs. Keywords Delay discounting * Area under the curve * Impulsivity * Cocaine, methamphetamine, Delay discounting describes how a reward loses value as a function of increasing delay to its receipt (Bickel & Marsch, 2001). As such, delay discounting provides a useful framework for [...]

Asserts that the use of multimedia furthers historians' work as opposed to changing it. Explores three objectives that multimedia allows historians to achieve: (1) the issue of representation; (2) the concern with emphasizing historical thinking skills; and (3) the topic of how others appropriate history. (CMK)

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1468-2303.2008.00448.x Byline: Gregory S. Brown (1) Author Affiliation: (1)University of Nevada, Las Vegas

Examines the relationship of career and academic major choice status to levels of state anxiety among undergraduate students (N=179) who completed questionnaires concerning their career development status. Results indicated subjects reporting previously chosen careers exhibited lower levels of state anxiety. (Author/RC)

Background and Objectives: Delay discounting is associated with numerous clinically significant aspects of substance use disorders (SUDs). Recent studies have demonstrated that different models for assessing discounting may result in disparate conclusions. The current study compared two discounting tasks: money now versus money later (M-M) and methamphetamine now versus money later (MA-M) among non-treatment seeking individuals (N = 59) with methamphetamine use disorder (MAUD). Results from each task were assessed using three different models for assessing delay discounting.Methods: Discounting data were fit to three models of discounting, log k using Mazur's hyperbolic formula, area under the curve (AUC), and an alternative AUC model in which the delay values have been log transformed (AUClog).Results: For both discounting tasks, the distribution of model-related outcomes were normally distributed when using log k and AUClog, but skewed for AUC. Discounting in the MA-M task was significantly greater compared to the M-M task when using log k and AUClog but not AUC.Conclusion: To our knowledge, the current study is the first to report significantly greater discounting in a MA-M relative to M-M discounting task among individuals with MAUD, an outcome consistent with other psychomotor stimulants and drugs of abuse.Scientific Significance: The differential results observed across the three discounting models reaffirm potential issues with AUC noted in recent studies and highlight that researchers must be cautious when deciding on their final model of discounting. (Am J Addict 2018;XX:1-8). [ABSTRACT FROM AUTHOR]

Discusses the life of French author Olympe de Gouges and her influence on women through her publications. How she was known as 'radical,' revolutionary,' 'the first French feminist,' and the 'militant abolitionist'; Investigation on the experiences of Gouges; Emphasis on centrality with ancient regime literary institutions and culture.

Determines the conformation of tetrasaccharides in an aqueous solution using high resolution nuclear magnetic resonance spectroscopy. Measurement of the dissociation rates and equilibrium binding constants of the glycoprotein complexes; Calculation of the bound conformations of the ligand; Use of the prolate ellipsoid model.

A number of studies have established that transcranial direct current stimulation (tDCS) modulates cortical excitability. We previously demonstrated polarity dependent changes in parietal lobe blood oxygen level dependent (BOLD) fMRI in a group of young adults during a spatial navigation task [15] . Here we used resting state functional connectivity (rsFC) to examine whether analogous changes were also evident during the resting state. Participants were randomized to either a parietal-anodal, frontal-cathodal (P+F−) or the opposite montage (P−F+) and received 20 min of tDCS (2 mA) before undergoing resting-state fMRI. rsFC was evaluated between the groups by placing a seed in the medial superior parietal lobule (mSPL), which was under the target electrode. rsFC between the mSPL and a number of other areas involved in spatial navigation, scene processing, and sensorimotor processing was significantly higher in the P+F− than the P−F+ group. Thus, the modulatory effects of tDCS were evident during rest and suggest that stimulation primes not just the underlying neocortex but an extended network that can be recruited as necessary during active task performance. [ABSTRACT FROM AUTHOR]

Methamphetamine (MA) is a highly addictive stimulant with recent upward trends in prevalence and associated public health problems. Drug demand, as assessed by hypothetical purchasing tasks, has been useful in addictions research and may help our understanding of the factors influencing MA use. However, no studies have assessed MA demand using current models of demand. The purpose of the current study was to assess demand for MA using a hypothetical drug purchasing task. Given high rates of cigarette smoking among MA users, it was of interest also to assess and compare demand for MA relative to cigarettes. Participants consisted of non-treatment-seeking volunteers with MA use disorder (N = 18), of whom 17 reported daily smoking. Results showed the exponentiated demand model provided a good fit to consumption data. Results from Bayesian generalized linear modeling demonstrated multiple positive relationships (posterior probability ≥75%) between self-reported drug use (days MA used in the past 30 days, cigarettes smoked per day) and indices of demand for each drug (Qo, Omax, Pmax, and break point). Comparing MA to cigarettes, results from Bayesian generalized linear mixed modeling revealed greater abuse liability for MA compared to cigarettes (posterior probability ≥99%) based on α and essential value. Overall, the findings of the current study support the feasibility and validity of the exponentiated demand model for assessing demand for drugs among individuals with MA use disorder. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Advances in structural and functional neuroimaging techniques have unquestionably improved understanding of the development and progression of Alzheimer disease (AD), with evidence supporting regional (and network) change that underlies cognitive decline across the "healthy" aging/mild cognitive impairment (MCI)/AD spectrum. This review focuses on visual rating scales and volumetric analyses that could be easily integrated into clinical practice, followed by a review of functional neuroimaging findings suggesting that widespread cerebral dysfunction underlies the learning and memory deficits in MCI. Evidence of preserved neuroplasticity in this population and that cognitive rehabilitation techniques may capitalize on this plasticity to improve cognition in those with MCI is also discussed., (Published by Elsevier Inc.)

Objectives: To examine interface pressure characteristics for two alternating air cell mattresses used for pressure ulcer prevention and treatment in a spinal cord injury population., Design: Prospective evaluation of Dynamic Flotation System (DFS) mattress and the Pegasus Airwave Mattress. Subjects acted as their own controls., Setting: Veterans Affairs Medical Center Spinal Cord Injury Unit., Participants: Convenience sample of 15 subjects with spinal cord injuries., Interventions: Minimum, maximum, and average interface pressures, and interface pressure range were measured by use of a force-sensing array system. The sacrum was chosen as the area of interest. Recordings lasted 9.5-10 minutes. Analyses were performed on 19 subjects in the supine and 45-degree upright positions for both mattresses., Results: Maximum and average interface pressures and interface pressure ranges were significantly higher, whereas minimum interface pressures were significantly lower on the Pegasus vs the DFS. For either mattress, the 45-degree position resulted in significantly greater interface pressures. There was no consistent correlation found between interface pressures and body mass index., Conclusions: Interface pressure characteristics of these two mattresses are very different, and neither mattress retains performance in the 45-degree position. Which interface pressure characteristic is most clinically relevant remains undetermined. Avoidance of the 45-degree sitting position is recommended.