title: Influence of the Hall effect on the reconnection rate at line-tied magnetic X-points

authors: Craig, Ian J.D.

subjects: magnetohydrodynamics

abstract: Context. The role of the Hall term in magnetic reconnection at line-tied planar magnetic X-points is explored.
Aims. The goal is to determine the reconnection scaling laws and to investigate how the reconnection rate depends on the size of the system in Hall magnetohydrodynamics (MHD).
Methods. The evolution of reconnective disturbances is determined numerically by solving the linearized compressible Hall MHD equations. Scaling laws are derived for the decay rate as a function of the dimensionless resistivity and ion inertial length.
Results. Although the Hall effect leads to an increase in the decay rate, this increase is shown to be moderated in larger systems. A key finding is that the Hall term contribution to the decay rate, normalized by the resistive decay rate, scales inversely with the system size L, approximately as L-2.
Conclusions. The evidence suggests that decay rate enhancements due to Hall effects in line-tied X-points are weakened for large-scale systems. The result may have important implications for modeling energy release in large-scale astrophysical plasma environments, such as solar flares.

text: Influence of the Hall effect on the reconnection rate at line-tied magnetic X-points Context. The role of the Hall term in magnetic reconnection at line-tied planar magnetic X-points is explored.
Aims. The goal is to determine the reconnection scaling laws and to investigate how the reconnection rate depends on the size of the system in Hall magnetohydrodynamics (MHD).
Methods. The evolution of reconnective disturbances is determined numerically by solving the linearized compressible Hall MHD equations. Scaling laws are derived for the decay rate as a function of the dimensionless resistivity and ion inertial length.
Results. Although the Hall effect leads to an increase in the decay rate, this increase is shown to be moderated in larger systems. A key finding is that the Hall term contribution to the decay rate, normalized by the resistive decay rate, scales inversely with the system size L, approximately as L-2.
Conclusions. The evidence suggests that decay rate enhancements due to Hall effects in line-tied X-points are weakened for large-scale systems. The result may have important implications for modeling energy release in large-scale astrophysical plasma environments, such as solar flares.

year: 2008

title: An experimental investigation of the self-management therapies: coverant control and covert sensitization

authors: Saunders, Steven Arthur

abstract: The relative efficacies of the SM techniques of Coverant Control (CC) and Covert Sensitization (CS), when applied singly and in combination, are investigated. Rate of cigarette smoking is the dependent variable. 

From an initial sample of 61 volunteers, smokers wishing to quit, 55 subjects (S’s) maintained contact and comprised the study group. Eleven S’s formed a non-treated control condition while the remaining 44 were distributed equally across 4 experimental conditions. These groups included a Placebo condition, CC, CS and CS + CC combined. 

It was hypothesised that CS and CC would prove more effective than a Placebo condition which involved contact only. It was further hypothesised that CS+ CC, administered as a combined package, would prove more effective in maintaining in-treatment gains at follow-up than when either of these treatments was administered singly.

The statistical analyses indicated no significant differences between the experimental groups receiving regular contact. All groups, except the non-treated controls, did reduce cigarette consumption while the programme lasted. However, on follow-up there was an almost uniform return toward baseline rates, with the SM treatment S’s not differing from those in the Placebo group.

These data are discussed in terms of possible implications for the development of SM techniques that are clinically useful with cigarette smokers.

text: An experimental investigation of the self-management therapies: coverant control and covert sensitization The relative efficacies of the SM techniques of Coverant Control (CC) and Covert Sensitization (CS), when applied singly and in combination, are investigated. Rate of cigarette smoking is the dependent variable. 

From an initial sample of 61 volunteers, smokers wishing to quit, 55 subjects (S’s) maintained contact and comprised the study group. Eleven S’s formed a non-treated control condition while the remaining 44 were distributed equally across 4 experimental conditions. These groups included a Placebo condition, CC, CS and CS + CC combined. 

It was hypothesised that CS and CC would prove more effective than a Placebo condition which involved contact only. It was further hypothesised that CS+ CC, administered as a combined package, would prove more effective in maintaining in-treatment gains at follow-up than when either of these treatments was administered singly.

The statistical analyses indicated no significant differences between the experimental groups receiving regular contact. All groups, except the non-treated controls, did reduce cigarette consumption while the programme lasted. However, on follow-up there was an almost uniform return toward baseline rates, with the SM treatment S’s not differing from those in the Placebo group.

These data are discussed in terms of possible implications for the development of SM techniques that are clinically useful with cigarette smokers.

year: 1973

title: Inter-propositional semantic relations and semantic relational encoding in written discourse in Maori: an investigation

authors: Houia, Waldo

subjects: Maori

abstract: This thesis is an investigation of the various ways in which relationships of meaning between propositions (such as reason-result and temporal overlap) are encoded (as clauses, sentences and groups of sentences) and signalled in Maori.
In Chapter 1, the overall research topic and research questions are outlined.
Chapter 2 locates the research on inter-propositional semantic relations with reference to the concept of cohesion which is central to inter-propositional relational signalling and encoding. Here, reference is made to a number of relevant publications in the area.
Chapter 3 provides an introductory examination of the role of cohesion in the encoding and signalling of inter-propositional semantic relations in Maori.
Chapter 4 introduces a corpus of written texts and examines that corpus in terms of the ways in which inter-propositional semantic relations are encoded.
Chapter 5 examines a number of textbooks designed for learners of both English and Maori in terms of the extent to which they draw upon insights relating to the operation of inter-propositional semantic relations.
In Chapter 6, the research findings are summarised and their implications for aspects of the teaching and learning of Maori are discussed. In addition, suggestions are made in relation to future research possibilities.
Overall, the conclusion reached is that the study of semantic relational encoding and signalling in Maori texts reveals a number of aspects of language that appear not to be commonly taught and suggests the need for further studies of this type.

text: Inter-propositional semantic relations and semantic relational encoding in written discourse in Maori: an investigation This thesis is an investigation of the various ways in which relationships of meaning between propositions (such as reason-result and temporal overlap) are encoded (as clauses, sentences and groups of sentences) and signalled in Maori.
In Chapter 1, the overall research topic and research questions are outlined.
Chapter 2 locates the research on inter-propositional semantic relations with reference to the concept of cohesion which is central to inter-propositional relational signalling and encoding. Here, reference is made to a number of relevant publications in the area.
Chapter 3 provides an introductory examination of the role of cohesion in the encoding and signalling of inter-propositional semantic relations in Maori.
Chapter 4 introduces a corpus of written texts and examines that corpus in terms of the ways in which inter-propositional semantic relations are encoded.
Chapter 5 examines a number of textbooks designed for learners of both English and Maori in terms of the extent to which they draw upon insights relating to the operation of inter-propositional semantic relations.
In Chapter 6, the research findings are summarised and their implications for aspects of the teaching and learning of Maori are discussed. In addition, suggestions are made in relation to future research possibilities.
Overall, the conclusion reached is that the study of semantic relational encoding and signalling in Maori texts reveals a number of aspects of language that appear not to be commonly taught and suggests the need for further studies of this type.

year: 2001