title: Coronal magnetic energy release by current sheet reconnection

authors: Heerikhuisen, Jacob

abstract: In this thesis we investigate the rapid release of energy in the solar corona, with a particular view to understanding the solar flare in which magnetic reconnection is thought to play a key role. A review of existing reconnection solutions is given in Chapters 2 and 3, with new analytic and numeric results are presented in subsequent chapters.

Although much of the work in this thesis is computational, numerical investigations are always motivated theoretically. In Chapters 4 and 5 several aspects of two dimensional reconnection are investigated using a periodic time-dependent incompressible code. One of the main points is to check the veracity of the analytic solution of Craig and Henton (1995) by running the code from general initial conditions. Other aspects of 2-D merging covered include the tearing mode instability, osculation and the effects of finite compressibility. 

We employ a 3-D time-dependent code, in Chapter 4, to check that the analytically predicted spine and fan forms develop from general initial conditions. Scalings with resistivity of the associated current structures are also investigated. Most of the analytic work so far has revolved around single null magnetic configurations. Chapter 6 focuses on reconnection solutions in the presence of multiple nulls. Finally, we look at an application of the analytic theory in the context of particle acceleration. In Chapter 7 we trace proton orbits using a physically plausible analytic current sheet solution.

text: Coronal magnetic energy release by current sheet reconnection In this thesis we investigate the rapid release of energy in the solar corona, with a particular view to understanding the solar flare in which magnetic reconnection is thought to play a key role. A review of existing reconnection solutions is given in Chapters 2 and 3, with new analytic and numeric results are presented in subsequent chapters.

Although much of the work in this thesis is computational, numerical investigations are always motivated theoretically. In Chapters 4 and 5 several aspects of two dimensional reconnection are investigated using a periodic time-dependent incompressible code. One of the main points is to check the veracity of the analytic solution of Craig and Henton (1995) by running the code from general initial conditions. Other aspects of 2-D merging covered include the tearing mode instability, osculation and the effects of finite compressibility. 

We employ a 3-D time-dependent code, in Chapter 4, to check that the analytically predicted spine and fan forms develop from general initial conditions. Scalings with resistivity of the associated current structures are also investigated. Most of the analytic work so far has revolved around single null magnetic configurations. Chapter 6 focuses on reconnection solutions in the presence of multiple nulls. Finally, we look at an application of the analytic theory in the context of particle acceleration. In Chapter 7 we trace proton orbits using a physically plausible analytic current sheet solution.

year: 2001

title: Proprioception and Performance: The role of below-knee compression garments and secondary tasks

authors: Ghai, Shashank

subjects: rehabilitation

abstract: Proprioception is an integral component of the voluntary and involuntary motor control processes of the body. Studies have suggested that proprioception plays an important prophylactic role in preventing injuries and can be disrupted by unnecessary conscious attention, imposed during high-stress conditions and/or due to physiological processes of ageing and injury. A systematic in-depth analysis of published literature was therefore conducted to evaluate the current state of literature pertinent to joint stabilizers (e.g. compression, taping, braces), secondary tasks and their effects on proprioception and stability. The first systematic review and meta-analysis revealed beneficial aspects of joint stabilizers, namely compression garments and taping on knee (Hedge’s g: 0.48, 95%CI: 0.35- 0.61) and ankle (0.42, 0.18- 0.65) joint proprioception. A second systematic review revealed a 1b level of evidence for the efficacy of secondary task training procedures to enhance postural stability amongst elderly participants. The review also demonstrated that secondary tasks are less efficient in enhancing postural stability among participants with prior history of falls. Following the literature review, gaps in literature were identified and experimental studies were designed to address these gaps. In the first quasi-experimental study, the effects of below-knee compression garments and secondary tasks on knee joint proprioception were studied. Statistical analysis revealed main effects of both compression (p<0.001) and secondary task (p=0.04). Thereafter, a second quasi-experimental study evaluated the effects of secondary tasks on proprioception (joint repositioning task), peak jump velocity, peak jump height, pre and post exercise. The study revealed a significant (p<0.05) enhancement of proprioception accuracy when a secondary task was implemented, pre and post exercise. Likewise, large and small effect sizes were calculated for proprioception and peak jump velocity, in between trails, pre and post exercise. The research carried out in the thesis is novel as it demonstrates that below-knee compression and secondary tasks can improve proprioception of the knee. Clinical implications are discussed with respect to proprioception in modern sports and rehabilitation settings.

text: Proprioception and Performance: The role of below-knee compression garments and secondary tasks Proprioception is an integral component of the voluntary and involuntary motor control processes of the body. Studies have suggested that proprioception plays an important prophylactic role in preventing injuries and can be disrupted by unnecessary conscious attention, imposed during high-stress conditions and/or due to physiological processes of ageing and injury. A systematic in-depth analysis of published literature was therefore conducted to evaluate the current state of literature pertinent to joint stabilizers (e.g. compression, taping, braces), secondary tasks and their effects on proprioception and stability. The first systematic review and meta-analysis revealed beneficial aspects of joint stabilizers, namely compression garments and taping on knee (Hedge’s g: 0.48, 95%CI: 0.35- 0.61) and ankle (0.42, 0.18- 0.65) joint proprioception. A second systematic review revealed a 1b level of evidence for the efficacy of secondary task training procedures to enhance postural stability amongst elderly participants. The review also demonstrated that secondary tasks are less efficient in enhancing postural stability among participants with prior history of falls. Following the literature review, gaps in literature were identified and experimental studies were designed to address these gaps. In the first quasi-experimental study, the effects of below-knee compression garments and secondary tasks on knee joint proprioception were studied. Statistical analysis revealed main effects of both compression (p<0.001) and secondary task (p=0.04). Thereafter, a second quasi-experimental study evaluated the effects of secondary tasks on proprioception (joint repositioning task), peak jump velocity, peak jump height, pre and post exercise. The study revealed a significant (p<0.05) enhancement of proprioception accuracy when a secondary task was implemented, pre and post exercise. Likewise, large and small effect sizes were calculated for proprioception and peak jump velocity, in between trails, pre and post exercise. The research carried out in the thesis is novel as it demonstrates that below-knee compression and secondary tasks can improve proprioception of the knee. Clinical implications are discussed with respect to proprioception in modern sports and rehabilitation settings.

year: 2016

title: The Buried Village, New Zealand - an example of dark tourism?

authors: Ryan, Chris

subjects: dark tourism

abstract: In 1886, the explosion of Mount Tarawera resulted in the loss of 150 lives and the burial of the village of Te Wairoa, the base from which tourists had visited the Pink and White Terraces, a silicone-stained natural formation then advertised as one of the natural wonders of the world. Since 1931, the buried site has itself been a tourist attraction and Smith and Croy have argued that it serves as an example of “dark tourism”. This paper uses a different methodology to argue that Lennon and Foley's original definition of dark tourism is precise, that the buried village of Te Wairoa does not meet that specification, but does support the model suggested by Sharpley, that the site's characteristics are those of grey tourism supply. However, the findings derived from a sample of over 600 respondents indicate that sites are complex packages of potential experiences, and are potentially multi-faceted in terms of the experiences they offer. It is also suggested that cultural components might play a role in the experience of what is “dark” about a site.

text: The Buried Village, New Zealand - an example of dark tourism? In 1886, the explosion of Mount Tarawera resulted in the loss of 150 lives and the burial of the village of Te Wairoa, the base from which tourists had visited the Pink and White Terraces, a silicone-stained natural formation then advertised as one of the natural wonders of the world. Since 1931, the buried site has itself been a tourist attraction and Smith and Croy have argued that it serves as an example of “dark tourism”. This paper uses a different methodology to argue that Lennon and Foley's original definition of dark tourism is precise, that the buried village of Te Wairoa does not meet that specification, but does support the model suggested by Sharpley, that the site's characteristics are those of grey tourism supply. However, the findings derived from a sample of over 600 respondents indicate that sites are complex packages of potential experiences, and are potentially multi-faceted in terms of the experiences they offer. It is also suggested that cultural components might play a role in the experience of what is “dark” about a site.

year: 2006