title: Gap junctions modulate seizures in a mean-field model of general anesthesia for the cortex

authors: Steyn-Ross, Moira L.

subjects: gap junctions

abstract: During slow-wave sleep, general anesthesia, and generalized seizures, there is an absence of consciousness. These states are characterized by low-frequency large-amplitude traveling waves in scalp electroencephalogram. Therefore the oscillatory state might be an indication of failure to form coherent neuronal assemblies necessary for consciousness. A generalized seizure event is a pathological brain state that is the clearest manifestation of waves of synchronized neuronal activity. Since gap junctions provide a direct electrical connection between adjoining neurons, thus enhancing synchronous behavior, reducing gap-junction conductance should suppress seizures; however there is no clear experimental evidence for this. Here we report theoretical predictions for a physiologically-based cortical model that describes the general anesthetic phase transition from consciousness to coma, and includes both chemical synaptic and direct electrotonic synapses. The model dynamics exhibits both Hopf (temporal) and Turing (spatial) instabilities; the Hopf instability corresponds to the slow ([≲8 Hz) oscillatory states similar to those seen in slow-wave sleep, general anesthesia, and seizures. We argue that a delicately balanced interplay between Hopf and Turing modes provides a canonical mechanism for the default non-cognitive rest state of the brain. We show that the Turing mode, set by gap-junction diffusion, is generally protective against entering oscillatory modes; and that weakening the Turing mode by reducing gap conduction can release an uncontrolled Hopf oscillation and hence an increased propensity for seizure and simultaneously an increased sensitivity to GABAergic anesthesia.

text: Gap junctions modulate seizures in a mean-field model of general anesthesia for the cortex During slow-wave sleep, general anesthesia, and generalized seizures, there is an absence of consciousness. These states are characterized by low-frequency large-amplitude traveling waves in scalp electroencephalogram. Therefore the oscillatory state might be an indication of failure to form coherent neuronal assemblies necessary for consciousness. A generalized seizure event is a pathological brain state that is the clearest manifestation of waves of synchronized neuronal activity. Since gap junctions provide a direct electrical connection between adjoining neurons, thus enhancing synchronous behavior, reducing gap-junction conductance should suppress seizures; however there is no clear experimental evidence for this. Here we report theoretical predictions for a physiologically-based cortical model that describes the general anesthetic phase transition from consciousness to coma, and includes both chemical synaptic and direct electrotonic synapses. The model dynamics exhibits both Hopf (temporal) and Turing (spatial) instabilities; the Hopf instability corresponds to the slow ([≲8 Hz) oscillatory states similar to those seen in slow-wave sleep, general anesthesia, and seizures. We argue that a delicately balanced interplay between Hopf and Turing modes provides a canonical mechanism for the default non-cognitive rest state of the brain. We show that the Turing mode, set by gap-junction diffusion, is generally protective against entering oscillatory modes; and that weakening the Turing mode by reducing gap conduction can release an uncontrolled Hopf oscillation and hence an increased propensity for seizure and simultaneously an increased sensitivity to GABAergic anesthesia.

year: 2012

title: The Nature of the Relationships between Social Networks, Interpersonal Trust, Management Support, and Knowledge Sharing

authors: Al Saifi, Said Abdullah

subjects: Social networks

abstract: Purpose – Past research has shown that, by implementing knowledge sharing, an organisation can maintain its long-term competitive advantage. Hence, this research will explore the nature of the relationships between social networks, interpersonal trust, management support, and knowledge sharing. 

Methodology/approach – In order to achieve the above purpose, semi-structured interviews were used to gather qualitative data. Interviewee participants included top and middle managers and frontline employees. The total number of participants included in the research was 25, equally representing five companies. The core business of all the companies was large-scale manufacturing. A grounded theory approach was used to analyse the data, augmented by the computer-assisted qualitative data analysis software, Nvivo.

Findings – The results reveal that social networks facilitate knowledge sharing in diverse ways. These ways are: the use of multiple communication styles, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. In addition, the data from the interviews suggests that, through various factors, the level of interpersonal trust, influences the extent to which employees are willing to share knowledge. These factors are organisational, relational, and individual factors. Furthermore, this study shows that both middle and top managers can play significant roles in facilitating knowledge sharing between employees. These roles are: encouragement of participation in decision-making, provision of recognition, breaking down of barriers, building up of teams, providing training or assigning others to do training, encouragement of training, communication, learning, putting knowledge into practice in the form of processes, and movement of employees.

Research contributions – Six models were developed from the qualitative analysis of the field data. The brainstorming and problem solving model identifies various steps for brainstorming and problem solving which influence social networks and knowledge sharing. The model of learning and teaching explains how social networks can be built based on the receivers’ levels of knowledge, namely, the novice, competent, expert, and proficient levels. The model of factors influencing social networks and knowledge sharing illustrates various factors. These are: using multiple communication strategies, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. The model of factors influencing interpersonal trust describes three factors for achieving such trust: organisational, relational, and individual factors. This model also elaborates on three factors that negatively influence interpersonal trust. These are division between departments, team conflict, and a sense of vulnerability. 

The model of the role of management teams in encouraging participation in decision-making elaborates on levels of decision-making among employees and the way in which knowledge flows between top and middle management and frontline employees. The integrative model deciphers the relationships between social networks, interpersonal trust, management support, openness, and knowledge sharing. In addition, the relationships between each area of emphasis and knowledge sharing are included in the model. Based on this model, a survey questionnaire was developed.

These models provide new insights into the relationships between social networks, interpersonal trust, management support, and knowledge sharing. By applying these models to appropriate field situations, both practitioners and academics may be able to improve current practices relating to how knowledge is shared and evolves within organisations.

text: The Nature of the Relationships between Social Networks, Interpersonal Trust, Management Support, and Knowledge Sharing Purpose – Past research has shown that, by implementing knowledge sharing, an organisation can maintain its long-term competitive advantage. Hence, this research will explore the nature of the relationships between social networks, interpersonal trust, management support, and knowledge sharing. 

Methodology/approach – In order to achieve the above purpose, semi-structured interviews were used to gather qualitative data. Interviewee participants included top and middle managers and frontline employees. The total number of participants included in the research was 25, equally representing five companies. The core business of all the companies was large-scale manufacturing. A grounded theory approach was used to analyse the data, augmented by the computer-assisted qualitative data analysis software, Nvivo.

Findings – The results reveal that social networks facilitate knowledge sharing in diverse ways. These ways are: the use of multiple communication styles, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. In addition, the data from the interviews suggests that, through various factors, the level of interpersonal trust, influences the extent to which employees are willing to share knowledge. These factors are organisational, relational, and individual factors. Furthermore, this study shows that both middle and top managers can play significant roles in facilitating knowledge sharing between employees. These roles are: encouragement of participation in decision-making, provision of recognition, breaking down of barriers, building up of teams, providing training or assigning others to do training, encouragement of training, communication, learning, putting knowledge into practice in the form of processes, and movement of employees.

Research contributions – Six models were developed from the qualitative analysis of the field data. The brainstorming and problem solving model identifies various steps for brainstorming and problem solving which influence social networks and knowledge sharing. The model of learning and teaching explains how social networks can be built based on the receivers’ levels of knowledge, namely, the novice, competent, expert, and proficient levels. The model of factors influencing social networks and knowledge sharing illustrates various factors. These are: using multiple communication strategies, brainstorming and problem solving, learning and teaching, training, employee rotation, and consultation. The model of factors influencing interpersonal trust describes three factors for achieving such trust: organisational, relational, and individual factors. This model also elaborates on three factors that negatively influence interpersonal trust. These are division between departments, team conflict, and a sense of vulnerability. 

The model of the role of management teams in encouraging participation in decision-making elaborates on levels of decision-making among employees and the way in which knowledge flows between top and middle management and frontline employees. The integrative model deciphers the relationships between social networks, interpersonal trust, management support, openness, and knowledge sharing. In addition, the relationships between each area of emphasis and knowledge sharing are included in the model. Based on this model, a survey questionnaire was developed.

These models provide new insights into the relationships between social networks, interpersonal trust, management support, and knowledge sharing. By applying these models to appropriate field situations, both practitioners and academics may be able to improve current practices relating to how knowledge is shared and evolves within organisations.

year: 2014

title: He Pikinga Waiora: Supporting Maori health organisations to respond to pre-diabetes

authors: Beaton, Angela

subjects: Science & Technology

abstract: Background
Type 2 Diabetes (T2D) is a common long-term condition affecting the health and wellbeing of New Zealanders; one in every four New Zealanders is pre-diabetic. Māori, the Indigenous people of New Zealand, are at an increased risk of developing pre-diabetes and T2D and there are significant inequities between Māori and non-Māori for T2D complications. The purpose of this study was to explore the questions of how the strengths of Māori heath organisations may be leveraged, and how the barriers and constraints experienced by Māori health organisations may be negotiated, for the benefit of Māori; and from a systems perspective, to identify strategic opportunities that may be considered and applied by Māori health organisations, funders and policy makers to respond more effectively to pre-diabetes and reduce health inequities between Māori and non-Māori.

Methods
Utilising case study methodology, a range of data sources were triangulated including nine semi-structured interviews, documents, and a diabetes system map to identify possible strategic opportunities for key stakeholders to respond more effectively to pre-diabetes.

Results
Key themes and possible actions to improve health outcomes for Māori with pre-diabetes include: (1) Recognising Māori health organisations as conduits for the community voice and influential partners in the community to effect change; (2) Strengthened partnerships with Māori health organisations for community benefit and to support measurable, evidence-based change and service delivery, particularly when Māori knowledge systems are viewed alongside a Western scientific approach; and (3) Intersectoral integration of health and social services to support provision of whānau-centred care and influence the social determinants of health and local environment.
Conclusions
Māori health organisations are important actors in systems seeking to improve outcomes and eliminate health inequities. Support from funders and policy makers will be required to build on the strengths of these organisations and to overcome system challenges. To realise improved health outcomes for Māori, the value placed on whānau and community perspectives not only needs to be acknowledged in the implementation of health interventions, health and social policies and funding arrangements, but performance measures, service design and delivery must evolve to accommodate these perspectives in practice.

text: He Pikinga Waiora: Supporting Maori health organisations to respond to pre-diabetes Background
Type 2 Diabetes (T2D) is a common long-term condition affecting the health and wellbeing of New Zealanders; one in every four New Zealanders is pre-diabetic. Māori, the Indigenous people of New Zealand, are at an increased risk of developing pre-diabetes and T2D and there are significant inequities between Māori and non-Māori for T2D complications. The purpose of this study was to explore the questions of how the strengths of Māori heath organisations may be leveraged, and how the barriers and constraints experienced by Māori health organisations may be negotiated, for the benefit of Māori; and from a systems perspective, to identify strategic opportunities that may be considered and applied by Māori health organisations, funders and policy makers to respond more effectively to pre-diabetes and reduce health inequities between Māori and non-Māori.

Methods
Utilising case study methodology, a range of data sources were triangulated including nine semi-structured interviews, documents, and a diabetes system map to identify possible strategic opportunities for key stakeholders to respond more effectively to pre-diabetes.

Results
Key themes and possible actions to improve health outcomes for Māori with pre-diabetes include: (1) Recognising Māori health organisations as conduits for the community voice and influential partners in the community to effect change; (2) Strengthened partnerships with Māori health organisations for community benefit and to support measurable, evidence-based change and service delivery, particularly when Māori knowledge systems are viewed alongside a Western scientific approach; and (3) Intersectoral integration of health and social services to support provision of whānau-centred care and influence the social determinants of health and local environment.
Conclusions
Māori health organisations are important actors in systems seeking to improve outcomes and eliminate health inequities. Support from funders and policy makers will be required to build on the strengths of these organisations and to overcome system challenges. To realise improved health outcomes for Māori, the value placed on whānau and community perspectives not only needs to be acknowledged in the implementation of health interventions, health and social policies and funding arrangements, but performance measures, service design and delivery must evolve to accommodate these perspectives in practice.

year: 2019