Filters
Availability
Publication Year
Resource Type
Faculty
School/Institute
Publication Search Results
Sort
Results per page
1 - 10 of 14
-
(2012)Journal ArticleIntroduction: There are clear personal, social and environmental benefits of cycling. However, safety concerns are among the frequently cited barriers to cycling. In Australia, there are no exposure-based measures of the rates of crash or ‘near miss’ experienced by cyclists. Design and setting: A prospective cohort study over 12 months, with all data collected via web-based online data entry. Participants: Two thousand adults aged 18 years and older, living in New South Wales (Australia), who usually bicycle at least once a month, will be recruited from March to November 2011. Methods: In the 12 months following enrolment, cyclists will be surveyed on 6 occasions (weeks 8, 16, 24, 32, 40, and 48 from the week of the enrolment survey). In these survey weeks, cyclists will be asked to provide daily reports of distance travelled; time, location and duration of trips; infrastructure used; crashes, near misses and crash-related injuries. Information on crashes and injuries will also be sought for the intervening period between the last and current survey. A subsample of participants will receive bicycle trip computers to provide objective measurement of distance travelled. Discussion: This study protocol describes the prospective cohort study developed to assess near misses, crashes and injuries among cyclists by time and distance travelled and by type of infrastructure used, with recruited participants entering data remotely using the internet. We expect to be able to calculate event rate according to exposure overall and for different infrastructure types and to report in-depth information about event causation.
-
(2012)Journal ArticleSince the 1991 enactment of mandatory helmet legislation (MHL) for cyclists in New South Wales (NSW), Australia, there has been extensive debate as to its effect on head injury rates at a population level. Many previous studies have focused on the impact of MHL around the time of enactment, while little has been done to examine the ongoing effects. We aimed to extend prior work by investigating long-term trends in cyclist head and arm injuries over the period 1991–2010. The counts of cyclists hospitalised with head or arm injuries were jointly modelled with log-linear regression. The simultaneous modelling of related injury mechanisms avoids the need for actual exposure data and accounts for the effects of changes in the cycling environment, cycling behaviour and general safety improvements. Models were run separately with population counts, bicycle imports, the average weekday counts of cyclists in Sydney CBD and cycling estimates from survey data as proxy exposures. Overall, arm injuries were higher than head injuries throughout the study period, consistent with previous post-MHL observations. The trends in the two injury groups also significantly diverged, such that the gap between rates increased with time. The results suggest that the initial observed benefit of MHL has been maintained over the ensuing decades. There is a notable additional safety benefit after 2006 that is associated with an increase in cycling infrastructure spending. This implies that the effect of MHL is ongoing and progress in cycling safety in NSW has and will continue to benefit from focusing on broader issues such as increasing cycling infrastructure.
-
(2013)Journal ArticleThis article responds to criticisms made in a rejoinder (Accident Analysis and Prevention 2012, 45: 107–109) questioning the validity of a study on the impact of mandatory helmet legislation (MHL) for cyclists in New South Wales, Australia. We systematically address the criticisms through clarification of our methods, extension of the original analysis and discussion of new evidence on the population-level effects of MHL. Extensions of our analysis confirm the original conclusions that MHL had a beneficial effect on head injury rates over and above background trends and changes in cycling participation. The ongoing debate around MHL draws attention away from important ways in which both safety and participation can be improved through investment in well-connected cycling infrastructure, fostering consideration between road users, and adequate legal protection for vulnerable road users. These are the essential elements for providing a cycling environment that encourages participation, with all its health, economic and environmental benefits, while maximising safety.
-
(2013)Journal ArticleThe aim of the current study was to examine cognitive and psychological factors hypothesized to affect responding to intrusions in obsessive-compulsive disorder (OCD). A group of individuals diagnosed with OCD was compared to a social phobia (SP) group and a nonclinical control group. Participants performed neuropsychological tasks, completed selfreport measures, and engaged in a self-relevant thought suppression task. The OCD group demonstrated worse working memory and response inhibition and had increased intrusions during the suppression task relative to comparison groups. They also reported more distress during the task relative to the nonclinical group, but not the SP group. Regression analyses revealed that beliefs about thought control failures, but not working memory or response inhibition, was associated with increased frequency of intrusions and greater distress during suppression. Findings support cognitive-behavioural models of OCD that emphasize the role of meta-beliefs in explaining the struggle with obsessional thoughts.
-
(2013)Journal ArticleBackground and Objectives: Thought-action fusion (TAF), or maladaptive cognitions regarding the relationship between mental events and behaviours, has been implicated in the development and maintenance of obsessive-compulsive disorder (OCD). As some religions promote TAF-like appraisals, it has been proposed that religiosity may play a role in the transformation of normally occurring intrusive thoughts into clinically distressing obsessions. No research, however, has experimentally investigated the mediating role of TAF on the relationship between religiosity and OC symptoms. Methods: 85 Christian, Jewish, and Atheist/Agnostic participants were exposed to an experimental thought-induction protocol and reported on their associated levels of distress, guilt, feelings of responsibility, and urge to suppress target intrusions experienced during a 5-minute monitoring period. Participants also completed measures of obsessive-compulsive symptomatology, TAF beliefs, and general psychopathology. Results: Using PROCESS and bootstrapping analyses, a test of the conditional indirect effects of religiosity on obsessive-compulsive symptoms revealed that Christianity moderated the effects of religiosity on moral TAF beliefs, which in turn mediated the relationship between religiosity and obsessive-compulsive symptoms. Furthermore, in the Christian group, moral TAF beliefs mediated the relationship between religiosity and ratings of guilt and responsibility following the experimental protocol. Limitations: The use of university students with moderate levels of religiosity. Conclusions: Collectively the results suggest that obsessional thinking is not attributable to religion per se, but that teachings underlying certain religious doctrines may fuel TAF beliefs that are implicated in the maintenance of OCD.
-
(2010)Journal ArticleStudy 1 evaluated the psychometric properties of the English version of the Thought Control Ability Questionnaire (TCAQ; Luciano, Algarabel, Tomás, & Martínez, 2005), an index of perceived control over intrusive cognitions. Confirmatory factor analysis in a sample of 720 University students revealed a clear uni-dimensional structure (after removal of items 5, 7, 8, 14, and 25) with high internal consistency (α = .87, 95% CI = [.86, .88]) and test-retest reliability after a six month interval (r = .68). Correlational analyses supported an inverse relationship with measures of depression, anxiety, maladaptive cognitive control strategies, and obsessive–compulsive symptomatology. Study 2 tested the ability of the TCAQ to predict successful cognitive control during an experimental suppression protocol. Results demonstrated that weak thought control ability was predictive of the frequency and associated levels of distress of a target thought while under instruction to suppress. Additionally, weak perceived thought control ability was predictive of increased efforts to suppress the target material. Collectively, results suggest that thought control ability is a measurable individual difference variable and that the TCAQ is a reliable index of perceived cognitive control.
-
(2012)Journal ArticleThe CACCC-box binding protein erythroid Krüppel-like factor (EKLF/KLF1) is a master regulator that directs the expression of many important erythroid genes. We have previously shown that EKLF drives transcription of the gene for a second KLF, basic Krüppel-like factor, or KLF3. We have now tested the in vivo role of KLF3 in erythroid cells by examining Klf3 knockout mice. KLF3-deficient adults exhibit a mild compensated anemia, including enlarged spleens, increased red pulp, and a higher percentage of erythroid progenitors, together with elevated reticulocytes and abnormal erythrocytes in the peripheral blood. Impaired erythroid maturation is also observed in the fetal liver. We have found that KLF3 levels rise as erythroid cells mature to become TER119(+). Consistent with this, microarray analysis of both TER119(-) and TER119(+) erythroid populations revealed that KLF3 is most critical at the later stages of erythroid maturation and is indeed primarily a transcriptional repressor. Notably, many of the genes repressed by KLF3 are also known to be activated by EKLF. However, the majority of these are not currently recognized as erythroid-cell-specific genes. These results reveal the molecular and physiological function of KLF3, defining it as a feedback repressor that counters the activity of EKLF at selected target genes to achieve normal erythropoiesis.
-
(2012)Journal ArticleContext: There is concern that exposure therapy, an evidence-based cognitive-behavioral treatment for posttraumatic stress disorder (PTSD), may be inappropriate for patients with co-occurring substance dependence (SD). Objective: To determine whether an integrated treatment for PTSD and SD, Concurrent Treatment of PTSD and Substance Use Disorders Using Prolonged Exposure (COPE), can achieve greater reductions in PTSD and SD symptom severity compared to treatment as usual (TAU) for SD. Design, Setting, and Patients: A randomized controlled trial of 103 participants who met DSM-IV-TR criteria for both PTSD and SD. Participants were recruited from 2007-2009 in Sydney, Australia, and randomized to one of two conditions. The treatment group received COPE plus TAU (COPE+TAU; n=55) and the control group received TAU alone (n=48). Outcomes were assessed at 9-months post-baseline, and interim measures collected at 6-weeks and 3-months post-baseline. Interventions: COPE consists of 13 individual 90-minute sessions (i.e., 19.5 hours) with a clinical psychologist. It represents an integration of existing evidence based manualized cognitive behavioral treatments for PTSD and SD, comprising psychoeducation, motivational enhancement, and cognitive behavioral therapy for PTSD and SD, including imaginal and in vivo exposure. Main outcome measures: Change in PTSD symptom severity as measured by the Clinician Administered PTSD Scale (CAPS; scale range 0-240), and change in severity of SD as measured by the number of dependence criteria met according to the Composite International Diagnostic Interview version 3.0 (CIDI; range 0-7), from baseline to 9-month follow-up. A change of 15 points on the CAPS scale and 1 dependence criteria on the CIDI were considered to be clinically significant. Results: From baseline to 9-month follow-up, significant reductions in PTSD symptom severity were found for both the treatment (mean difference -38.24, 95%CI: -47.93 - -28.54) and control group (mean difference -22.14, 95%CI: -30.33 - -13.95), however, the treatment group demonstrated a significantly greater reduction in PTSD symptom severity compared to the control group (mean difference -16.09, 95%CI: -29.00 to -3.19). No significant between group difference was found in relation to improvement in severity of SD (0.43 v 0.52; IRR 0.85, 95%CI: 0.60 - 1.21), nor were there any significant between group differences in relation to changes in substance use, depression or anxiety. Conclusions: Among patients with PTSD and SD, the combined use of COPE+TAU, compared with TAU alone, resulted in improvement in PTSD symptom severity without an increase in severity of SD. Trial registration: Registration number ISRCTN12908171; URL: http://www.controlled-trials.com/ISRCTN12908171/mills
-
(2010)Journal ArticleAlthough the normal probability distribution is the cornerstone of applying statistical methodology; data do not always meet the necessary normal distribution assumptions. In these cases, researchers often transform non normal data to a distribution that is approximately normal. Power transformations constitute a family of transformations, which include logarithmic and fractional exponent transforms. The Box-Cox method offers a simple method for choosing the most appropriate power transformation. Another option for data that is positively skewed, often used when measuring reaction times, is the Ex-Gaussian distribution which is a combination of the exponential and normal distributions. In this paper, the Box-Cox power transformation and Ex-Gaussian distribution will be discussed and compared in the context of positively skewed data. This discussion will demonstrate that the Box-Cox power transformation is simpler to apply and easier to interpret than the Ex-Gaussian distribution.
-
(2011)Journal ArticleThe study aimed to assess the effect of compulsory cycle helmet legislation on cyclist head injuries given the ongoing debate in Australia as to the efficacy of this measure at a population level. We used hospital admissions data from New South Wales, Australia, from a 36 month period centred at the time legislation came into effect. Negative binomial regression of hospital admission counts of head and limb injuries to cyclists was performed to identify differential changes in head and limb injury rates at the time of legislation. Interaction terms were included to allow different trends between injury types and pre- and post-law time periods. To avoid the issue of lack of cyclist exposure data, we assumed equal exposures between head and limb injuries which allowed an arbitrary proxy exposure to be used in the model. As a comparison, analyses were also performed for pedestrian data to identify which of the observed effects were specific to cyclists. In general the models identified a decreasing trend in injury rates prior to legislation, an increasing trend thereafter and a drop in rates at the time legislation was enacted, all of which were thought to represent background effects in transport safety. Head injury rates decreased significantly more than limb injury rates at the time of legislation among cyclists but not among pedestrians. This additional benefit was attributed to compulsory helmet legislation. Despite numerous data limitations, we identified evidence of a positive effect of compulsory cycle helmet legislation on cyclist head injuries at a population level such that repealing the law cannot be justified.