title: A novel approach to investigate depression symptoms in the ageing population using Generalizability theory

authors: Saiji Kumar, Sruthy

subjects: Depression

abstract: As depression is common in older people and confers a significant risk for dementia, its accurate assessment is essential to monitor and treat the condition. The 15-item Geriatric Depression Scale (GDS-15) is a widely used assessment tool for measuring depression in aged populations, and its psychometric properties have been recently improved using Rasch analysis. However, its temporal reliability and ability to distinguish between dynamic and enduring symptoms of depression have not been examined using the appropriate methodology. Distinguishing enduring aspects of depression helps to estimate the risks of depression and the long-lasting effects of an intervention while identifying and targeting dynamic symptoms may enhance the efficiency of a treatment. Generalizability theory (G-theory) is a suitable method to distinguish between enduring and dynamic symptoms of depression, evaluate the overall reliability of the GDS-15, and identify sources of measurement error. This study applied G-theory to the longitudinal GDS-15 data of 354 participants aged 70 years and older from the Sydney Memory and Ageing Study, collected over ten years with 2-4 years intervals. The GDS-15 demonstrated strong reliability and generalizability of its scores across the sample population and assessment occasions in measuring enduring symptoms of depression (Ga= 0.82, Gr=0.90). In addition, three dynamic symptoms of depression were identified, namely helplessness, hopelessness, and loss of interest in activities, which did not affect the overall strong reliability of the GDS-15. This study demonstrated that the GDS-15 is a reliable measure for assessing enduring symptoms of depression and can be used to evaluate the efficacy of depression treatments and monitor depression levels in older adults. Dynamic symptoms identified by this study are more amendable and can be targeted in the first place to enhance effectiveness of a treatment.

text: A novel approach to investigate depression symptoms in the ageing population using Generalizability theory As depression is common in older people and confers a significant risk for dementia, its accurate assessment is essential to monitor and treat the condition. The 15-item Geriatric Depression Scale (GDS-15) is a widely used assessment tool for measuring depression in aged populations, and its psychometric properties have been recently improved using Rasch analysis. However, its temporal reliability and ability to distinguish between dynamic and enduring symptoms of depression have not been examined using the appropriate methodology. Distinguishing enduring aspects of depression helps to estimate the risks of depression and the long-lasting effects of an intervention while identifying and targeting dynamic symptoms may enhance the efficiency of a treatment. Generalizability theory (G-theory) is a suitable method to distinguish between enduring and dynamic symptoms of depression, evaluate the overall reliability of the GDS-15, and identify sources of measurement error. This study applied G-theory to the longitudinal GDS-15 data of 354 participants aged 70 years and older from the Sydney Memory and Ageing Study, collected over ten years with 2-4 years intervals. The GDS-15 demonstrated strong reliability and generalizability of its scores across the sample population and assessment occasions in measuring enduring symptoms of depression (Ga= 0.82, Gr=0.90). In addition, three dynamic symptoms of depression were identified, namely helplessness, hopelessness, and loss of interest in activities, which did not affect the overall strong reliability of the GDS-15. This study demonstrated that the GDS-15 is a reliable measure for assessing enduring symptoms of depression and can be used to evaluate the efficacy of depression treatments and monitor depression levels in older adults. Dynamic symptoms identified by this study are more amendable and can be targeted in the first place to enhance effectiveness of a treatment.

year: 2022

title: Topics in Energy Release and Particle Acceleration in the Heliosphere

authors: Armstrong, Craig Keith

subjects: astrophysics

abstract: This thesis investigates both the release of energy in solar flares, and the acceleration and transport of particles in various astrophysical situations. While numerical simulations are central to this thesis, these are always motivated by analytical arguments.

A review of flare energy release is given in Chapter 2, with results presented in Chapters 3 and 4. The main goal of the flare work is to investigate the effect of viscosity on energy release rates. Scaling arguments and exact solutions of the magnetohydrodynamic equations are used to interpret the results of two-dimensional numerical simulations of magnetic reconnection. The results support viscous energy dissipation accounting for a significant fraction of flare energy release.

Chapter 5 contains an introduction to astrophysical particle acceleration, using the Fokker-Planck formulation. The theory introduced in this chapter is used to study electron transport in solar flare loops (Section 5.5). A key aspect of the analysis is the expression of the Fokker-Planck equation as a system of stochastic differential equations. A generalisation to the flare loop hard X-ray emission prediction of Conway et al. (1998) is obtained, giving a stronger dependence on density for dispersed initial distributions.

Chapter 6 uses the methods of the previous chapter to study the acceleration of cosmic-rays at the heliospheric termination shock. The applicability of the focused acceleration mechanism of Schlickeiser and Shalchi (2008) is examined using numerical simulations, which are interpreted using analytical arguments based on averaging the stochastic equations. The results show significant limitations in assuming a near-isotropic distribution, a requirement for the focused acceleration mechanism. In addition, momentum diffusion provides a significant effect that cannot be neglected.  The theory is extended to include focused deceleration and pure momentum diffusion.

text: Topics in Energy Release and Particle Acceleration in the Heliosphere This thesis investigates both the release of energy in solar flares, and the acceleration and transport of particles in various astrophysical situations. While numerical simulations are central to this thesis, these are always motivated by analytical arguments.

A review of flare energy release is given in Chapter 2, with results presented in Chapters 3 and 4. The main goal of the flare work is to investigate the effect of viscosity on energy release rates. Scaling arguments and exact solutions of the magnetohydrodynamic equations are used to interpret the results of two-dimensional numerical simulations of magnetic reconnection. The results support viscous energy dissipation accounting for a significant fraction of flare energy release.

Chapter 5 contains an introduction to astrophysical particle acceleration, using the Fokker-Planck formulation. The theory introduced in this chapter is used to study electron transport in solar flare loops (Section 5.5). A key aspect of the analysis is the expression of the Fokker-Planck equation as a system of stochastic differential equations. A generalisation to the flare loop hard X-ray emission prediction of Conway et al. (1998) is obtained, giving a stronger dependence on density for dispersed initial distributions.

Chapter 6 uses the methods of the previous chapter to study the acceleration of cosmic-rays at the heliospheric termination shock. The applicability of the focused acceleration mechanism of Schlickeiser and Shalchi (2008) is examined using numerical simulations, which are interpreted using analytical arguments based on averaging the stochastic equations. The results show significant limitations in assuming a near-isotropic distribution, a requirement for the focused acceleration mechanism. In addition, momentum diffusion provides a significant effect that cannot be neglected.  The theory is extended to include focused deceleration and pure momentum diffusion.

year: 2014

title: “Seeing” Kāpō Māori: Making visible the experiences of Kāpō Māori during and after COVID-19

authors: Masters-Awatere, Bridgette

abstract: A scoping project focused on the intersection of Māori and the framing of vision impairments (disability) within the context of a pandemic response (in this instance COVID-19). Specifically, we were interested in the experiences of kāpō Māori during and post COVID-19 in order to centre the cultural and health needs of kāpō Māori in a culturally responsive manner. We highlight the aspirations that kāpō Māori have for themselves and their whānau, and to identify the facilitators and barriers that kāpō Māori and their whānau face in achieving these

text: “Seeing” Kāpō Māori: Making visible the experiences of Kāpō Māori during and after COVID-19 A scoping project focused on the intersection of Māori and the framing of vision impairments (disability) within the context of a pandemic response (in this instance COVID-19). Specifically, we were interested in the experiences of kāpō Māori during and post COVID-19 in order to centre the cultural and health needs of kāpō Māori in a culturally responsive manner. We highlight the aspirations that kāpō Māori have for themselves and their whānau, and to identify the facilitators and barriers that kāpō Māori and their whānau face in achieving these

year: 2021