Retrieval analysis of 38 WFC3 transmission spectra and resolution of the normalisation degeneracy

A comprehensive analysis of 38 previously published Wide Field Camera 3 (WFC3) transmission spectra is performed using a hierarchy of nested-sampling retrievals: with versus without clouds, grey versus non-grey clouds, isothermal versus non-isothermal transit chords and with water, hydrogen cyanide and/or ammonia. We revisit the "normalisation degeneracy": the relative abundances of molecules are degenerate at the order-of-magnitude level with the absolute normalisation of the transmission spectrum. Using a suite of mock retrievals, we demonstrate that the normalisation degeneracy may be partially broken using WFC3 data alone, even in the absence of optical/visible data and without appealing to the presence of patchy clouds, although lower limits to the mixing ratios may be prior-dominated depending on the measurement uncertainties. With James Webb Space Telescope-like spectral resolutions, the normalisation degeneracy may be completely broken from infrared spectra alone. We find no trend in the retrieved water abundances across nearly two orders of magnitude in exoplanet mass and a factor of 5 in retrieved temperature (about 500 to 2500 K). We further show that there is a general lack of strong Bayesian evidence to support interpretations of non-grey over grey clouds (only for WASP-69b and WASP-76b) and non-isothermal over isothermal atmospheres (no objects). 35 out of 38 WFC3 transmission spectra are well-fitted by an isothermal transit chord with grey clouds and water only, while 8 are adequately explained by flat lines. Generally, the cloud composition is unconstrained.Comment: Accepted by MNRAS. 33 pages, 29 figures, 3 table

Characterising Exoplanet Atmospheres using Traditional Methods and Supervised Machine Learning

Since the discovery of the first extrasolar planets over 25 years ago, the field of exoplanet research has exploded. Today we have over 4000 confirmed exoplanets, with a wide variety of sizes, orbital separations, and host stars. The characterisation of this diverse population of objects has led to exciting discoveries about the conditions of alien worlds. Future technological advances are expected to provide an abundance of exoplanet spectra with a higher precision and sensitivity than ever before. This calls for a parallel advancement in the accuracy and speed of atmospheric models to interpret this influx of data. In this thesis, my work on atmospheric retrievals is presented. Starting with traditional techniques, my first thesis paper applies a Bayesian retrieval in combination with an analytical atmospheric model to the Hubble transmission spectra of 38 different exoplanets. My second paper considers the theoretical model of the sodium doublet, and the effect of dropping the assumption of local-thermodynamic equilibrium. From here, I went on to develop a method that uses supervised machine learning to improve the speed and efficiency of the retrieval. This method was explained and tested in a collaborative paper with machine learning experts in Bern. The machine learning retrieval is then applied in several follow-up studies, covering a range of different scenarios. One of these was my final thesis paper, which further extends the new retrieval to high-resolution spectra using the cross-correlation function. In addition to my own papers, I have contributed to a number of studies led by collaborators by running retrievals, assisting other students, and participating in scientific discussions. I have also worked on several observing proposals, both for high-resolution ground-based observatories and for the upcoming James Webb Space Telescope. I plan to continue my work on exoplanet characterisation and machine learning in the future, using the technique to combine high- and low-resolution spectra to gain further insight into the atmospheres of these distant planets. The speed and efficiency of machine learning will also allow for statistical studies of exoplanets as the quantity of atmospheric spectra from new and upcoming telescopes escalates. Not only will these studies teach us about the conditions and potential habitability of exoplanets, but they will also answer questions about planet formation, diverse chemical processes, and the uniqueness of our solar system

NGX-4010, a capsaicin 8% patch, for the treatment of painful HIV-associated distal sensory polyneuropathy: integrated analysis of two phase III, randomized, controlled trials

BACKGROUND HIV-associated distal sensory polyneuropathy (HIV-DSP) is the most frequently reported neurologic complication associated with HIV infection. NGX-4010 is a capsaicin 8% dermal patch with demonstrated efficacy in the treatment of HIV-DSP. Data from two phase III, double-blind studies were integrated to further analyze the efficacy and safety of NGX-4010 and explore the effect of demographic and baseline factors on NGX-4010 treatment in HIV-DSP. METHODS Data from two similarly designed studies in which patients with HIV-DSP received NGX-4010 or a low-concentration control patch (capsaicin 0.04% w/w) for 30 or 60 minutes were integrated. Efficacy assessments included the mean percent change from baseline in Numeric Pain Rating Scale (NPRS) scores to Weeks 2-12. Safety and tolerability assessments included adverse events (AEs) and pain during and after treatment. RESULTS Patients (n = 239) treated with NGX-4010 for 30 minutes demonstrated significantly (p = 0.0026) greater pain relief compared with controls (n = 100); the mean percent change in NPRS scores from baseline to Weeks 2-12 was -27.0% versus -15.7%, respectively. Patients who received a 60-minute application of NGX-4010 (n = 243) showed comparable pain reductions (-27.5%) to patients treated for 30 minutes, but this was not statistically superior to controls (n = 115). NGX-4010 was effective regardless of gender, baseline pain score, duration of HIV-DSP, or use of concomitant neuropathic pain medication, although NGX-4010 efficacy was greater in patients not receiving concomitant neuropathic pain medications. NGX-4010 was well tolerated; the most common AEs were application-site pain and erythema, and most AEs were mild to moderate. The transient increase in pain associated with NGX-4010 treatment decreased the day after treatment and returned to baseline by Day 2. CONCLUSIONS A single 30-minute application of NGX-4010 provides significant pain relief for at least 12 weeks in patients with HIV-DSP and is well tolerated. TRIAL REGISTRATION C107 = NCT00064623; C119 = NCT00321672

Building Wellbeing in People With Chronic Conditions: A Qualitative Evaluation of an 8-Week Positive Psychotherapy Intervention for People Living With an Acquired Brain Injury

Research indicates that Acquired Brain Injury (ABI) is associated with significant and chronic impairment across multiple areas of functioning including physical, cognitive, emotional and behavioural domains. Whilst impairments associated with ABI can be ameliorated, cure is seldom possible. The emergence of positive psychology reflects a paradigm shift in health and wellbeing research, highlighting the role of character strengths, positive emotions, meaning, and resilience. Positive psychology interventions have been demonstrated to improve wellbeing in a variety of populations, although research investigating the impact of positive psychotherapy for people living with ABI are sparse. Here we characterize the experience of an 8-week positive psychotherapy intervention for 13 people living with ABI including four mentors and nine participants using thematic analysis of transcripts collected during mini-groups and one-to-one interviews. Six main themes were identified including empowerment, social opportunity, coping, cultivation of positive emotion, consolidation of skills and barriers. Results indicated that wellbeing can be promoted and improved in individuals with ABI. Recent theoretical developments in wellbeing science highlight scope to improve the intervention by connecting individuals to their communities and spending time in nature

Student nurses' life story work on inpatient wards

Life story work can be a valuable resource on dementia inpatient wards as student mental health nurses who participants in this research project discovere

Assessing psychological adjustment and cultural reintegration after military service: development and psychometric evaluation of the post-separation Military-Civilian Adjustment and Reintegration Measure (M-CARM)

Background: The transition out of military service and subsequent reintegration to civilian life has been established as a period associated with an increased risk of psychological adjustment difficulties, psychiatric disorders and suicide risk, yet no tool exists to measure cultural and psychological adjustment following permanent separation from the military. This study describes the two-phase mixed-methods development and validation of the self-report Military-Civilian Adjustment and Reintegration Measure (M-CARM). Methods: In Phase I, four focus groups (n = 20) and semi-structured one-on-one interviews (n = 80) enabled thematic analysis and generation of 53 initial items that were reviewed by an expert multidisciplinary panel (n = 12) and piloted for clarity and relevance in an Australian service-veteran sample (n = 11). In Phase II, psychometric properties of the 47 items resulting from Phase I were evaluated with online assessment of a convenience sample of transitioned Australian Defence Force veterans (n = 725). Analyses included exploratory and confirmatory factor analyses, as well as evaluation of test-retest reliability, internal consistency, and convergent, divergent and discriminant validity. Results: Exploratory factor analysis on a randomized split-half sample (n = 357), resulted in a 21-item, five-factor solution of Purpose and Connection, Help seeking, Beliefs about civilians, Resentment and regret, and Regimentation, explaining 53.22% of the variance. Confirmatory factor analysis (n = 368) verified this factor structure without modification (χ2 = 304.96, df = 160; CFI = .96, TLI = .94, NFI = .91, RMSEA = .05). Strong convergent, divergent and discriminant validity was demonstrated as M-CARM scores significantly correlated with related constructs assessed by standardised clinical measures as well as differentiated groups based on three binary reintegration items, with large effect sizes (d = > 1). Strong test-retest reliability for the total score (n = 186, r = .93) and excellent internal consistency (n = 725, a = .90) were also found. Conclusions: Results provide promising evidence the M-CARM is a valid, reliable measure of psychological and cultural reintegration to civilian life, with potential for considerable clinical and research application.This study was funded by RSL Queensland

The experiences of wives following acquired brain injury (ABI). A qualitative analysis exploring realisations of change following the ABI of a “loved one”.

The experiences of family members following Acquired Brain Injury (ABI) are well established, with spouses in particular facing multiple relational and personal changes. Qualitative studies have analysed accounts pertaining to a range of sequelae, however, “change” itself has yet to be addressed. This study explored the experiences of realisation of change for married women living with their husbands following ABI. Nine participants took part in semi-structured interviews focussing on becoming aware of changes in both their spouse and themselves post-injury. An Interpretative Phenomenological Analysis (IPA) was completed, arriving at two overarching themes; “bravery to face changes” and “lost and trapped in an unsolvable maze,” with accompanying subthemes. Participants generally experienced realisation of change gradually, in some cases finding strategies to control their exposure to distress. They often referred to “acceptance,” which held varied meanings, and metaphors appeared to aid personal meaning making. Relationship changes generated both dilemmas and the feeling of being trapped. Overall, this study contributes greater insights into the experiential mechanisms underpinning realisation of change in spouses after brain injury