Methods and strategies for recruiting participants to walking promotion programmes

Introduction: Recruitment of participants is an integral but challenging process in walking promotion programmes. A lack of information about what was done during recruitment is a limiting factor in knowing what works best and why certain approaches might be worth replicating. Aim: The aim of this thesis was to conduct formative research on the process of recruitment to walking programmes. The objectives included: systematically reviewing the literature, qualitatively investigating practice and the participants' perspective, evaluating a novel approach to recruitment and to produce a set of best practice guidelines for recruitment. Methods: A mixed methods design shaped the methodology in this thesis and included: a systematic review of the literature; qualitative research including focus groups and interviews; and a process evaluation of a novel approach to recruitment. Results: The systematic review showed our understanding of recruitment is limited by a lack of reported information including the lack of a fir for purpose definition. Qualitative research with practitioners showed that there is a demand for best practice guidelines, while participants reported most often being recruited by word of mouth and being attracted to walking groups with broad health appeals. Process evaluation of a strategic approach to recruitment demonstrated that, despite complex and challenging circumstances, disadvantaged men could be recruited to walking programmes. These findings have been combined and developed into guidelines for recruitment. What this study adds to the literature: These studies have shown that recruitment is an active and complex process, not one single method, and that effective recruitment is dependent on the capacity of the recruitment team. The proposed guidelines provide a basis for future learning about conducting, reporting and identifying effective recruitment processes.Introduction: Recruitment of participants is an integral but challenging process in walking promotion programmes. A lack of information about what was done during recruitment is a limiting factor in knowing what works best and why certain approaches might be worth replicating. Aim: The aim of this thesis was to conduct formative research on the process of recruitment to walking programmes. The objectives included: systematically reviewing the literature, qualitatively investigating practice and the participants' perspective, evaluating a novel approach to recruitment and to produce a set of best practice guidelines for recruitment. Methods: A mixed methods design shaped the methodology in this thesis and included: a systematic review of the literature; qualitative research including focus groups and interviews; and a process evaluation of a novel approach to recruitment. Results: The systematic review showed our understanding of recruitment is limited by a lack of reported information including the lack of a fir for purpose definition. Qualitative research with practitioners showed that there is a demand for best practice guidelines, while participants reported most often being recruited by word of mouth and being attracted to walking groups with broad health appeals. Process evaluation of a strategic approach to recruitment demonstrated that, despite complex and challenging circumstances, disadvantaged men could be recruited to walking programmes. These findings have been combined and developed into guidelines for recruitment. What this study adds to the literature: These studies have shown that recruitment is an active and complex process, not one single method, and that effective recruitment is dependent on the capacity of the recruitment team. The proposed guidelines provide a basis for future learning about conducting, reporting and identifying effective recruitment processes

Application of Argon Plasma Technology to Hydrophobic and Hydrophilic Microdroplet Generation in PDMS Microfluidic Devices

Abstract Application of Argon Plasma Technology to Hydrophobic and Hydrophilic Microdroplet Generation in PDMS Microfluidic Devices Brennan Graham Microfluidics has gained popularity over the last decade due to the ability to replace many large, expensive laboratory processes with small handheld chips with a higher throughput due to the small channel dimensions [1]. Droplet microfluidics is the field of fluid manipulation that takes advantage of two immiscible fluids to create droplets from the geometry of the microchannels. This project includes the design of a microfluidic device that applies the results of an argon plasma surface treatment to polydimethylsiloxane (PDMS) to successfully produce both hydrophobic and hydrophilic surfaces to create oil in water (O/W) and water in oil (W/O) microdroplets. If an argon plasma surface treatment renders the surface of PDMS hydrophilic, then O/W microdroplets can be created and integrated into a larger microdroplet emulsion device. The major aims of this project include: (1) validating previously established Cal Poly lab protocols to produce W/O droplets in hydrophobic PDMS microdroplet generators (2) creating hydrophilic PDMS microdroplet generators (3) making oil in water droplets in hydrophilic PDMS microdroplet generators (4) designing a multilayer microfluidic device to transfer W/O droplets to a second hydrophilic PDMS microdroplet generator v W/O droplets were successfully created and transferred to a second hydrophilic PDMS device. The hydrophilic PDMS device also produced O/W droplets in separate testing from the multilayered microfluidic PDMS device. The ultimate purpose of this project is to create a multilayer microdroplet generator that produces water in oil in water (W/O/W) microdroplet emulsions through a stacked device design that can be used in diagnostic microdroplet applications. Thesis Supervisor: Dave Clague Title: Professor of Biomedical Engineerin

Aerogel keystones: extraction of complete hypervelocity impact events from aerogel collectors

In January 2006, the Stardust mission will return the first samples from a solid solar-system body since Apollo, and the first samples of contemporary interstellar dust ever collected. Although sophisticated laboratory instruments exist for the analysis of Stardust samples, techniques for the recovery of particles and particle residues from aerogel collectors remain primitive. Here we describe our recent progress in developing techniques for extracting small volumes of aerogel, which we have called ``keystones,'' which completely contain particle impacts but minimize the damage to the surrounding aerogel collector. These keystones can be fixed to custom-designed micromachined silicon fixtures (so-called ``microforklifts''). In this configuration the samples are self-supporting, which can be advantageous in situations in which interference from a supporting substrate is undesirable. The keystones may also be extracted and placed onto a substrate without a fixture. We have also demonstrated the capability of homologously crushing these unmounted keystones for analysis techniques which demand flat samples.Comment: 17 pages, 11 figures, submitted to Meteoritics and Planetary Scienc

Reducing dose for digital cranial radiography : The increased source to the image-receptor distance approach

This investigation proposes that an increased source to the image-receptor distance (SID) technique can be used to optimize occipital frontal and lateral cranial radiographs acquired with direct digital radiography. Although cranial radiography is not performed on a routine basis, it should nonetheless be optimized to keep the dose to the patient as low as reasonably achievable, particularly because it can form part of the facial bone and sinus series. Dose measurements were acquired at various SIDs, and image quality was assessed using visual grading analysis. Statistically significant reductions in the effective dose between 19.2% and 23.9% were obtained when the SID was increased from the standard 100 to 150 cm (P ≤.05), and visual grading analysis scores indicate that image quality remained diagnostically acceptable for both projections. This investigation concludes that increasing the SID effectively optimizes occipital frontal and lateral skull radiographs. Radiology departments must be advised of the benefits of this technique with the goal of introducing an updated reference SID of 150 cm into clinical practice.Peer reviewe

Focused deterrence:a protocol for a realist multisite randomised controlled trial for evaluating a violence prevention intervention in the UK

Introduction: Focused deterrence (FD) is a frequently cited intervention for preventing violence, particularly against violent urban gangs. The Youth Endowment Fund (YEF) believes it could be effective in the UK, based primarily on research conducted in the US. However, we contend that these studies have inadequate methodological designs, lack of rigorous testing, and small sample sizes. Therefore, the evidence supporting focused deterrence as an effective method, particularly outside the US, is inconclusive. The aim of the protocol is to better understand the potential effects of FD in the context of the UK, using a multisite evaluation experimental design to more closely investigate the evidence of its likely impact.Methods:  We planned a realist randomised controlled trial. The design is focused on a multisite trial consisting of two-arm randomised experiments in five locations. Each trial location will test their implementation of a core programme specified by the funder. The multisite nature will allow us to understand differential impacts between locations, improving the external validity of the results. Participants will be randomly selected from a wider pool of eligible individuals for the intervention. We estimate a sample size of approximately N = 1, 700 individuals is required. Based on this pooled sample size, a relative reduction of 26% would be detectable in 80% of trials. The trial is coupled with a formative process evaluation of delivery and fidelity. The formative evaluation will use a mixed methods design. The qualitative aspect will include semi-structured cross-sectional and longitudinal interviews with programme leads, programme delivery team, and programme participants, as well as observations of the meetings between the programme delivery team (i.e., community navigators/mentors) and programme participants. The quantitative data for the formative evaluation will be gathered by the sites themselves and consist of routine outcome performance monitoring using administrative data. Sampling for interviews and observations will vary, with the researchers aiming for a higher number of individuals included in the first round of cross-sectional interviews and retaining as many as possible for repeat interviews and observations.Discussion: This protocol outlines the process and impact evaluation methodology for the most extensive multisite evaluation of focused deterrence to date in the UK. Spanning five distinct sites with seven trials, the evaluation includes a cohort of 2, 000 individuals, marking it as the only multisite trial of focused deterrence. Employing an integrated realist evaluation framework, the study uses qualitative and quantitative research methods. The anticipated findings will offer pivotal insights for formulating future violence prevention policies in the UK. They are also expected to contribute significantly to the corpus of literature on violence prevention and intervention evaluation.Trial registration:  Protocol registration: ISRCTN: 11650008 4th June 2023. </p

An empirical comparison of convertible bond valuation models

This paper empirically compares three convertible bond valuation models. We use an innovative approach where all model parameters are estimated by the Marquardt algorithm using a subsample of convertible bond prices. The model parameters are then used for out-of-sample forecasts of convertible bond prices. The mean absolute deviation is 1.86% for the Ayache-Forsyth-Vetzal model, 1.94% for the Tsiveriotis-Fernandes model, and 3.73% for the Brennan-Schwartz model. For this and other measures of fit, the Ayache-Forsyth-Vetzal and Tsiveriotis-Fernandes models outperform the Brennan-Schwartz model

Serving Those Who Served: Renegotiating Support and Benefits for U.S. Military Veterans with Less than Honorable Discharges

Approximately 1 in 7 veterans are discharged from the military under less than “Honorable” conditions. Veterans with less than “Honorable” discharges experience bias and stigma related to their discharge, which can lead to elevated risk for behavioral and mental health challenges and homelessness. This brief summarizes the different military discharge types, explains how less than “Honorable” discharges can affect veteran health, identifies groups of veterans who are at risk of receiving a less than “Honorable” discharge, and makes policy recommendations for the Department of Defense (DoD), civilian employers, and community healthcare providers

Recruiting participants to walking intervention studies: a systematic review

Most researchers who are conducting physical activity trials face difficulties in recruiting participants who are representative of the population or from specific population groups. Participants who are often the hardest to recruit are often those who stand to benefit most (the least active, from ethnic and other minority groups, from neighbourhoods with high levels of deprivation, or have poor health). The aim of our study was to conduct a systematic review of published literature of walking interventions, in order to identify the impact, characteristics, and differential effects of recruitment strategies among particular population groups. We conducted standard searches for studies from four sources, (i) electronic literature databases and websites, (ii) grey literature from internet sources, (iii) contact with experts to identify additional "grey" and other literature, and (iv) snowballing from reference lists of retrieved articles. Included studies were randomised controlled trials, controlled before-and-after experimental or observational qualitative studies, examining the effects of an intervention to encourage people to walk independently or in a group setting, and detailing methods of recruitment. Forty seven studies met the inclusion criteria. The overall quality of the descriptions of recruitment in the studies was poor with little detail reported on who undertook recruitment, or how long was spent planning/preparing and implementing the recruitment phase. Recruitment was conducted at locations that either matched where the intervention was delivered, or where the potential participants were asked to attend for the screening and signing up process. We identified a lack of conceptual clarity about the recruitment process and no standard metric to evaluate the effectiveness of recruitment. Recruitment concepts, methods, and reporting in walking intervention trials are poorly developed, adding to other limitations in the literature, such as limited generalisability. The lack of understanding of optimal and equitable recruitment strategies evident from this review limits the impact of interventions to promote walking to particular social groups. To improve the delivery of walking interventions to groups which can benefit most, specific attention to developing and evaluating targeted recruitment approaches is recommended