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5. Police Stops: A Comparative Perspective on Governance

Author

Aston, Elizabeth, Rowe, Mike, Fazekas, János, Lennon, Genevieve, De Kimpe, Sofie, Aston, Elizabeth, Series Editor, Rowe, Michael, Series Editor, De Kimpe, Sofie, editor, Fazekas, János, editor, Lennon, Genevieve, editor, and Rowe, Mike, editor

Published
2024
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8. Prospective associations between sleep disturbances and cannabis use among Veterans: A behavioral economic approach

Author

Berey, Benjamin L, Aston, Elizabeth R, Kearns, Nathan T, McGeary, John E, Borsari, Brian, and Metrik, Jane

Subjects
Biological Psychology, Clinical and Health Psychology, Psychology, Sleep Research, Cannabinoid Research, Mental health, Marijuana purchase task, Sleep behaviors, Cannabis demand, Marijuana, Mechanism, Public Health and Health Services, Substance Abuse, Public health, Biological psychology, Clinical and health psychology
Abstract

BackgroundVeterans often use cannabis for sleep despite limited evidence of its efficacy. Moreover, how sleep disturbances impact cannabis use longitudinally is unclear. We applied a behavioral economic framework to examine whether sleep disturbances and cannabis demand (i.e., relative value) were related risk-factors for future cannabis use and problems.MethodsVeterans deployed post-9/11/2001 who reported past 6-month cannabis use at baseline (n = 126) completed surveys on their sleep disturbances, demand via the Marijuana Purchase Task (MPT), and cannabis use. Mediation analyses using Hayes' PROCESS Macro and zero-inflated negative binomial models tested indirect effects of baseline sleep disturbances on 12-month cannabis use frequency, quantity, and problems via 6-month cannabis demand (i.e., intensity, Omax, Pmax, and breakpoint).ResultsOnly Omax (i.e., maximum expenditure for cannabis) was a significant mediator for 12-month cannabis use quantity and problems when examined concurrently with other demand indices after controlling for covariates. Intensity (i.e., purchase at zero cost) was a significant mediator for 12-month cannabis use frequency when examined concurrently with other demand indices in models controlling for lifetime cannabis use, but not past 30-day use at baseline.ConclusionCannabis demand, specifically intensity and Omax, may help to identify Veterans with sleep disturbances who are at increased risk for escalating their cannabis use. Subsequent research should assess the extent that sleep disturbances impact cannabis demand in the context of withdrawal, which will inform novel prevention and intervention strategies geared toward reducing negative cannabis-related outcomes among Veterans.

Published
2022

13. Technology and Police Legitimacy

Author

Aston, Elizabeth, Wells, Helen, Bradford, Ben, O’Neill, Megan, Aston, Elizabeth, Series Editor, Rowe, Michael, Series Editor, Verhage, Antoinette, editor, Easton, Marleen, editor, and De Kimpe, Sofie, editor

Published
2022
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20. Medicinal Versus Recreational Cannabis Use Among Returning Veterans

Author

Metrik, Jane, Bassett, Shayna S, Aston, Elizabeth R, Jackson, Kristina M, and Borsari, Brian

Subjects
Biological Psychology, Psychology, Mental Health, Depression, Behavioral and Social Science, Post-Traumatic Stress Disorder (PTSD), Anxiety Disorders, Cannabinoid Research, Substance Misuse, Sleep Research, Brain Disorders, Mental health, Good Health and Well Being, PTSD, cannabis, medical marijuana, sleep, veteran, Applied and developmental psychology, Clinical and health psychology, Social and personality psychology
Abstract

BackgroundAlthough increasing rates of cannabis use and cannabis use disorder (CUD) are well-documented among veterans, little is known about their use of cannabis specifically for medicinal purposes. The present study characterizes such use and compares veterans reporting cannabis use for medicinal (n = 66) versus recreational (n = 77) purposes on (a) sociodemographic factors, (b) psychiatric disorders (posttraumatic stress disorder [PTSD], major depressive disorder [MDD], and CUD), (c) other substance use, (d) reasons for cannabis use and cannabis-related problems, and (e) physical and mental health.MethodsParticipants were veterans deployed post 9/11/2001 recruited from a Veterans Health Administration (VHA) facility (N = 143; mean [SD] age = 30.0 [6.6]; mean [SD] deployments = 1.7 [1.1]) who reported past-year cannabis use.ResultsThe most frequently endorsed conditions for medicinal cannabis (MC) use were anxiety/stress, PTSD, pain, depression, and insomnia. In logistic regression analyses adjusted for frequency of cannabis use, MC users were significantly more likely (OR = 3.16) to meet criteria for PTSD than recreational cannabis (RC) users. Relative to RC users, MC users reported significantly greater motivation for using cannabis to cope with sleep disturbance as well as significantly poorer sleep quality and worse physical health.ConclusionsVeterans who use cannabis for medicinal purposes differ significantly in sleep, physical and mental health functioning than veterans who use cannabis for recreational purposes. PTSD and sleep problems may be especially relevant issues to address in screening and providing clinical care to returning veterans who are using cannabis for medicinal purposes.

Published
2018

32. Critical mutation rates in small populations

Author

Aston, Elizabeth Jane

Subjects
576.5, QH426 Genetics
Abstract

Mutation introduces change at the sequence level. There is a critical mutation rate above which changes occur too frequently for natural selection to maintain the population's genetic makeup. This thesis examines the relationship between this critical mutation rate and the number of individuals in the adapting population. It presents an algorithmic method capable of providing widely applicable results in haploid and diploid populations, and varies this method against analytical models for the error threshold. Use of the method led to the discovery of an exponential relationship between the critical mutation rate and population size, particularly strong in small populations with 100 individuals or less, contradicting the existing idea that critical mutation rate and population size are independent. The critical mutation rate (and error threshold) were found to be lower in diploids due to differences in recombination. Analysis of the survival-of-the-fittest to survival-of-the-flattest transition enabled improvement of existing definitions of the critical mutation rate. Development of a faster algorithm capable of running experiments with parameter values within the range found in nature began the process of bridging the gap between artificial and biological evolution. A link was established between the exponential model and natural mutation rates. Increasing the gene length by a factor of 10 was found to decrease both the critical mutation rate and error threshold by an order of magnitude. Natural mutation rates lie below these values, although further work is required to establish any trend. A potential link has been established between the critical mutation rate, error threshold, and optimal mutation rate control theory. Future work may develop the algorithmic method to include more complex features of biological populations, and go on to determine the effect the exponential model can have on population extinction, recovery, and conservation.

Published
2014

33. Monotonicity of Fitness Landscapes and Mutation Rate Control

Author

Belavkin, Roman V., Channon, Alastair, Aston, Elizabeth, Aston, John, Krasovec, Rok, and Knight, Christopher G.

Subjects
Quantitative Biology - Populations and Evolution, Computer Science - Information Theory, Computer Science - Neural and Evolutionary Computing, Mathematics - Optimization and Control, 05B25 26A48 68W20 68T05 92B20 93E35 93B27
Abstract

A common view in evolutionary biology is that mutation rates are minimised. However, studies in combinatorial optimisation and search have shown a clear advantage of using variable mutation rates as a control parameter to optimise the performance of evolutionary algorithms. Much biological theory in this area is based on Ronald Fisher's work, who used Euclidean geometry to study the relation between mutation size and expected fitness of the offspring in infinite phenotypic spaces. Here we reconsider this theory based on the alternative geometry of discrete and finite spaces of DNA sequences. First, we consider the geometric case of fitness being isomorphic to distance from an optimum, and show how problems of optimal mutation rate control can be solved exactly or approximately depending on additional constraints of the problem. Then we consider the general case of fitness communicating only partial information about the distance. We define weak monotonicity of fitness landscapes and prove that this property holds in all landscapes that are continuous and open at the optimum. This theoretical result motivates our hypothesis that optimal mutation rate functions in such landscapes will increase when fitness decreases in some neighbourhood of an optimum, resembling the control functions derived in the geometric case. We test this hypothesis experimentally by analysing approximately optimal mutation rate control functions in 115 complete landscapes of binding scores between DNA sequences and transcription factors. Our findings support the hypothesis and find that the increase of mutation rate is more rapid in landscapes that are less monotonic (more rugged). We discuss the relevance of these findings to living organisms.

Published
2012
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34. “It would really support the wider harm reduction agenda across the board”: A qualitative study of the potential impacts of drug checking service delivery in Scotland

Author

Falzon, Danilo, primary, Parkes, Tessa, additional, Carver, Hannah, additional, Masterton, Wendy, additional, Wallace, Bruce, additional, Craik, Vicki, additional, Measham, Fiona, additional, Sumnall, Harry, additional, Gittins, Rosalind, additional, Hunter, Carole, additional, Watson, Kira, additional, Mooney, John D., additional, and Aston, Elizabeth V., additional

Published
2023
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38. Drug use and offending : the relationship over the teenage years

Author

Aston, Elizabeth V.

Subjects
364
Abstract

This thesis aims to describe and explain how drug use and offending are linked over the teenage years. This research was conducted in association with the Edinburgh Study of Youth Transitions and Crime, a longitudinal study. I carried out secondary analysis of six sweeps of annual self-report questionnaire data, from age 12 to 17. I also conducted in-depth interviews with 27 cohort members at age 18 to 19. Findings suggest that the relationship between drug use and offending is stronger earlier (as opposed to later) in the teenage years. The social meaning of drug use changes over this period. Early onset drug users described having ‘nothing to do’ and engaged in drug use and offending in street-based peer groups. Those who did not begin using other drugs until later in their teens portrayed their drug use as a legitimate life experience, quite separate from offending. Young people’s drug use and offending can be explained with reference to differential levels of informal social control and peer group interactions. Differential opportunity structures, which change over the course of the teenage years, are shaped by socio-structural positions and informal social controls. It is within the context of peer group interactions that the social acceptability of behaviours may be defined, drug use and offending opportunities occur and decisions are made. Involvement in offending weakens social bonds and deepens involvement in deviant contexts, leading to drug use or further offending. However, ‘turning points’ such as starting one’s own family, gaining employment or changing friendship group facilitate the reduction of involvement in offending and drug use.

Published
2008

44. A Descriptive Analysis of a Popular Pregnancy Forum: Comments on the Developmental Consequences of Cannabis Use on Offspring.

Author

Micalizzi, Lauren, Aston, Elizabeth R., Nesi, Jacqueline, Price, Dayna, and Gunn, Rachel L.

Abstract

Objective: Pregnant and postpartum people want more and higher quality information about the effects of perinatal cannabis use (PCU) on child health, and they turn to anonymous sources of information, such as online pregnancy forums, to make decisions about its use. This study characterized perceptions of the developmental impact of PCU on children via a narrative evaluation of a public forum on which people discuss a range of issues around cannabis use. Method: A random sample of 10 threads per month from June 2020 to May 2021 were scraped from the "Ganja Mamas" forum on Whattoexpect.com. Posts were analyzed if they discussed use of cannabis during pregnancy or lactation and children. A qualitative coding structure was developed from a literature review on PCU and was refined for inclusion of emergent topics. Posts were evaluated by two coders using applied thematic analysis and were assessed using an open coding process to identify key topics. Associated codes were grouped into themes. Results: Posters (a) discussed the negative and positive impact of PCU on child physical, cognitive, and socioemotional development; (b) garnered information about PCU from sources other than medical providers; and (c) discussed harm-reduction approaches to reduce impacts of PCU on child health. Conclusions: There is a need for stigma-free support around PCU decision-making for people who select into discussion forums designed for communication and support around parental cannabis use. This forum presents a fruitful opportunity for intervention to encourage health-promoting behaviors through the provision of evidence-based information. [ABSTRACT FROM AUTHOR]

Published
2024
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