title: Electrical Conductivity of Brain Cortex Slices in Seizing and Non-seizing States

authors: Elbohouty, Maher

subjects: Electrical Conductivity

abstract: The electrical conductivity of thin living slices of mouse cerebral cortex is measured. Two only out of fifteen different attempting ways were effective. I have successfully measured the electrical conductivity of mouse brain cortex in seizing and non-seizing conditions. The first successful approach is called 	the van der Pauw method, where four silver-silver chloride cylindrical wire electrodes were immersed in full length at the corners of the sample. The second is a one-dimensional technique where two flat electrodes were placed on either face of the 400 micrometer thick samples.

In both methods the electrodes were connected to an Agilent E4980A impedance monitor. The conductivity at 10 kHz of each sample was calculated based on measurements of injected current and potential difference between electrodes. Both approaches were validated by measuring electrical conductivities of known solutions. There were two main challenges: the small size of the sample and keeping it alive. I overcame these challenges by suitable electrodes and fast measuring equipment (Agilent E4980A LCR meter). For the one-dimensional technique I also measured the conductivity across the frequency range 20 Hz to 2 MHz.

The results consistently show the mean conductivity of seizing brain tissue is significantly lower than that of non-seizing tissue at 10 kHz. Also, the conductivity of seizing slices is lower than the conductivity of non-seizing slices over the frequency range 20 Hz to 2 MHz. 

These results suggest a link between electrical conductivity and seizure activity. I have not investigated the causes of these differences but explanations consistent with the literature are a change in chemical environment during seizure or a reduction in gap junction connectivity.

text: Electrical Conductivity of Brain Cortex Slices in Seizing and Non-seizing States The electrical conductivity of thin living slices of mouse cerebral cortex is measured. Two only out of fifteen different attempting ways were effective. I have successfully measured the electrical conductivity of mouse brain cortex in seizing and non-seizing conditions. The first successful approach is called 	the van der Pauw method, where four silver-silver chloride cylindrical wire electrodes were immersed in full length at the corners of the sample. The second is a one-dimensional technique where two flat electrodes were placed on either face of the 400 micrometer thick samples.

In both methods the electrodes were connected to an Agilent E4980A impedance monitor. The conductivity at 10 kHz of each sample was calculated based on measurements of injected current and potential difference between electrodes. Both approaches were validated by measuring electrical conductivities of known solutions. There were two main challenges: the small size of the sample and keeping it alive. I overcame these challenges by suitable electrodes and fast measuring equipment (Agilent E4980A LCR meter). For the one-dimensional technique I also measured the conductivity across the frequency range 20 Hz to 2 MHz.

The results consistently show the mean conductivity of seizing brain tissue is significantly lower than that of non-seizing tissue at 10 kHz. Also, the conductivity of seizing slices is lower than the conductivity of non-seizing slices over the frequency range 20 Hz to 2 MHz. 

These results suggest a link between electrical conductivity and seizure activity. I have not investigated the causes of these differences but explanations consistent with the literature are a change in chemical environment during seizure or a reduction in gap junction connectivity.

year: 2013

title: Using agent-based modelling for small area household projections: a New Zealand case study

authors: Marais, Anton Louis

subjects: Household distribution

abstract: In New Zealand, the Resource Management Act 1991 (RMA) is the guiding legislation that sets out how the environment is managed. The territorial authorities are charged with regulating how the environment is managed in their jurisdiction. In order to effectively manage any resource, good and robust planning processes are required. Population change is the factor that has the greatest impact on the environment, and is one of the most challenging to regulate, thus for the territorial authority planners, knowing where and when infrastructure investment is most likely required is key to fulfilling their statutory requirement.
This line of investigation has been driven by an ever increasing need for more spatially detailed projections of where and when changes are most likely to take place. The investigation and subsequent development of spatially detailed household projections transcends three territorial authorities in the lower Waikato river catchment situated in New Zealand.
An agent-based model was developed in which the individual agents were households. The aim of the model was to produce a simplified simulation of the location choices made by the members of a household in a housing market that is governed by councils’ infrastructure provision, household rents, transport costs and the benefit derived from the neighbourhood amenities and the environment. This model simulates the distribution of households over a twelve year period from 2013 to 2025. In the model the households were programmed to move to vacant properties in order to minimise their residential costs. Each time an agent moves this provides new potential options for all other households; thus the simulation runs and the households move until all households settle in their least cost locations, representing the distribution of households in 2025. The incorporation of multiple territorial authorities provides a more holistic approach than the prevailing approach which is based on disaggregating top level projection with the no further account of population movement outside the top-level migration assumption.
The results of the model calibration indicate the model performs well with a 16.6% RMSE at the smallest spatial unit. The projected results produce growth patterns that fall within the expectations of planning staff of the councils. These staff members have affirmed the model’s and input assumptions, and indicate the outcomes to be both useful and plausible. 
The results demonstrate the relationship between the councils and their respective growth plan strategies. The scenarios were developed to, demonstrate the relationship between the availability of vacant land and the cost to occupy a property, which ultimately impacts the flux of residents to or away from the city. 
With some broad assumptions and limitations, this model is distinctive in its approach as it is developed with the intention of being an applied tool to be used by the three councils. It has the further distinction as modelling the behaviours of individual households rather than the behaviours of an entire population, which is the unique in New Zealand and amongst a few applied models of this nature wide (Triantakonstantis & Mountrakis, 2012).

text: Using agent-based modelling for small area household projections: a New Zealand case study In New Zealand, the Resource Management Act 1991 (RMA) is the guiding legislation that sets out how the environment is managed. The territorial authorities are charged with regulating how the environment is managed in their jurisdiction. In order to effectively manage any resource, good and robust planning processes are required. Population change is the factor that has the greatest impact on the environment, and is one of the most challenging to regulate, thus for the territorial authority planners, knowing where and when infrastructure investment is most likely required is key to fulfilling their statutory requirement.
This line of investigation has been driven by an ever increasing need for more spatially detailed projections of where and when changes are most likely to take place. The investigation and subsequent development of spatially detailed household projections transcends three territorial authorities in the lower Waikato river catchment situated in New Zealand.
An agent-based model was developed in which the individual agents were households. The aim of the model was to produce a simplified simulation of the location choices made by the members of a household in a housing market that is governed by councils’ infrastructure provision, household rents, transport costs and the benefit derived from the neighbourhood amenities and the environment. This model simulates the distribution of households over a twelve year period from 2013 to 2025. In the model the households were programmed to move to vacant properties in order to minimise their residential costs. Each time an agent moves this provides new potential options for all other households; thus the simulation runs and the households move until all households settle in their least cost locations, representing the distribution of households in 2025. The incorporation of multiple territorial authorities provides a more holistic approach than the prevailing approach which is based on disaggregating top level projection with the no further account of population movement outside the top-level migration assumption.
The results of the model calibration indicate the model performs well with a 16.6% RMSE at the smallest spatial unit. The projected results produce growth patterns that fall within the expectations of planning staff of the councils. These staff members have affirmed the model’s and input assumptions, and indicate the outcomes to be both useful and plausible. 
The results demonstrate the relationship between the councils and their respective growth plan strategies. The scenarios were developed to, demonstrate the relationship between the availability of vacant land and the cost to occupy a property, which ultimately impacts the flux of residents to or away from the city. 
With some broad assumptions and limitations, this model is distinctive in its approach as it is developed with the intention of being an applied tool to be used by the three councils. It has the further distinction as modelling the behaviours of individual households rather than the behaviours of an entire population, which is the unique in New Zealand and amongst a few applied models of this nature wide (Triantakonstantis & Mountrakis, 2012).

year: 2016

title: Claiming space and restoring harmony within hui whakatika

authors: Berryman, Mere

subjects: Maori

abstract: The time has come for indigenous, specifically Māori psychologies, to move from the margins, and claim legitimate space within the discipline of psychology (MPRU, 2007). Phinney and Rotheram (1987) argue that there are ethnicallylinked ways of thinking, feeling and acting that are acquired through socialisation. The message implicit in this statement has profound implications for a discipline that seeks to understand and respond to the intricacies of human behaviour. Although the epistemological paradigms emerging from the experiences of indigenous minorities such as Māori may offer a challenge to mainstream knowledge and perspectives (Gordon, 1997), it is clear that disregarding such alternatives may well leave the discipline of psychology impoverished. On the other hand, paying attention to alternative paradigms may well serve to enrich this discipline. This paper presents two successful Hui Whakatika that were led by Māori in mainstream settings. Particular dimensions of, and congruencies between both are explored. The first highlights the vital role of a kaumatua in facilitating and guiding the entire process; the second focuses on the role and experiences of a kaitakawaenga as he works collaboratively with whānau members to find resolution and restore harmony.

text: Claiming space and restoring harmony within hui whakatika The time has come for indigenous, specifically Māori psychologies, to move from the margins, and claim legitimate space within the discipline of psychology (MPRU, 2007). Phinney and Rotheram (1987) argue that there are ethnicallylinked ways of thinking, feeling and acting that are acquired through socialisation. The message implicit in this statement has profound implications for a discipline that seeks to understand and respond to the intricacies of human behaviour. Although the epistemological paradigms emerging from the experiences of indigenous minorities such as Māori may offer a challenge to mainstream knowledge and perspectives (Gordon, 1997), it is clear that disregarding such alternatives may well leave the discipline of psychology impoverished. On the other hand, paying attention to alternative paradigms may well serve to enrich this discipline. This paper presents two successful Hui Whakatika that were led by Māori in mainstream settings. Particular dimensions of, and congruencies between both are explored. The first highlights the vital role of a kaumatua in facilitating and guiding the entire process; the second focuses on the role and experiences of a kaitakawaenga as he works collaboratively with whānau members to find resolution and restore harmony.

year: 2008