title: Assessment of demand for food under concurrent PR and FR schedules in the brushtail possum (Trichosurus Vulpecula)

authors: Cameron, Kristie Elizabeth

abstract: The aim of this study was to compare the demand by possums for foods under different arrangements of concurrent progressive-ratio and fixed-ratio schedules of reinforcement. In Experiment 1, every possible food pair made up of berries, chicken, egg, foliage, insects, and mushroom was presented (30 pairs in total). The requirement on the progressive-ratio schedule increased within a session and the fixed-ratio was kept constant at 30. In Experiment 2, a subset of the foods from Experiment 1 were used (chicken, mushroom, egg, and berries) and in separate conditions the fixed-ratio was either 30 or 10 responses. In Experiment 3, the foods were the same as used in Experiment 2 and the progressive-ratio schedule increased every five sessions and the fixed-ratio was kept constant at 30. Exponential models of demand were applied to consumption rates to compare the parameters of initial demand, essential value and Pmax, and break point and cross point across foods. The models described the data well and consumption rates were similar when the incrementing schedules increased within- and across sessions. Demand was highest for berries, egg, and locust in Experiment 1 and egg and chicken in Experiments 2 and 3. This finding has practical implications for understanding possum food preferences in the wild as a function of other available food sources and for informing pest control strategies of potential lures.

text: Assessment of demand for food under concurrent PR and FR schedules in the brushtail possum (Trichosurus Vulpecula) The aim of this study was to compare the demand by possums for foods under different arrangements of concurrent progressive-ratio and fixed-ratio schedules of reinforcement. In Experiment 1, every possible food pair made up of berries, chicken, egg, foliage, insects, and mushroom was presented (30 pairs in total). The requirement on the progressive-ratio schedule increased within a session and the fixed-ratio was kept constant at 30. In Experiment 2, a subset of the foods from Experiment 1 were used (chicken, mushroom, egg, and berries) and in separate conditions the fixed-ratio was either 30 or 10 responses. In Experiment 3, the foods were the same as used in Experiment 2 and the progressive-ratio schedule increased every five sessions and the fixed-ratio was kept constant at 30. Exponential models of demand were applied to consumption rates to compare the parameters of initial demand, essential value and Pmax, and break point and cross point across foods. The models described the data well and consumption rates were similar when the incrementing schedules increased within- and across sessions. Demand was highest for berries, egg, and locust in Experiment 1 and egg and chicken in Experiments 2 and 3. This finding has practical implications for understanding possum food preferences in the wild as a function of other available food sources and for informing pest control strategies of potential lures.

year: 2015

title: Investigation and Modelling of Fetal Sheep Maturation

authors: Xu, Yanyang

subjects: EEG Signal Processing

abstract: In this thesis, I study the maturational changes of the fetal sheep ECoG (electrocorticogram) in its third-trimester of gestation (95-140 days of gestation), investigate three continuum models for electrical behaviour of the cortex, and tune the parameters in one of these models to generate the discontinuous EEG waves in the immature cortex. Visual inspection of the ECoG time-series shows that the third-trimester of fetal sheep is comprised of two stages: early third-trimester characterised by bursting activity separated by silent intervals, and late third-trimester with well-defined SWS (slow wave sleep) and REM (rapid eye movement) sleep states. For the late third-trimester, the results of power, correlation time, and SVD (singular value decomposition) entropy analysis demonstrate that the sleep state change is a cortical phase transition—with SWS-to-REM transition being a first-order transition, and REM-to-SWS second-order. Further analyses by correlation time, SVD entropy, and spectral edge frequency display that the differentiation of the two distinct SWS and REM sleep states occurs at about 125 dGA (day gestational age). Spectral analysis divides the third-trimester into four stages in terms of the frequency and amplitude variations of the major resonances. Spindle-like resonances only occur in the first stage. A power surge is observed immediately prior to the emergence of the two sleep states. Most significant changes of the spectrum occur during the fourth stage for both SWS (in amplitude) and REM (in frequency) sleep states. For the modelling of the immature cortex, different theoretical descriptions of cortical behaviour are investigated, including the ccf (cortical column field) model of J. J. Wright, and the Waikato cortical model. For the ccf model at centimetric scale, the time-series, fluctuation power, power law relation, gamma oscillation, phase relation between excitatory and inhibitory elements, power spectral density, and spatial Fourier spectrum are quantified from numerical simulations. From these simulations, I determined that the physiologically sophisticated ccf model is too large and unwieldy for easy tuning to match the electrical response of the immature cortex. The Waikato near-far fast-soma model is constructed by incorporating the back-propagation effect of the action potential into the Waikato fast-soma model, state equations are listed and stability prediction are performed by varying the gap junction diffusion strength, subcortical drive, and the rate constants of the near- and far-dendritic tree. In the end, I selected the classic and simpler Waikato slow-soma mean-field model to use for my immature cortex simulations. Model parameters are customised based on the physiology of the immature cortex, including GABA (an inhibitory neurotransmitter in adult) excitatory effect, number of synaptic connections, and rate constants of the IPSPs (inhibitory postsynaptic potential). After hyperpolarising the neuron resting voltage sufficiently to cause the immature inhibitory neuron to act as an excitatory agent, I alter the rate constant of the IPSP, and study the stability of the immature cortex. The bursting activity and quiet states of the discontinuous EEG are simulated and the gap junction diffusion effect in the immature cortex is also examined. For a rate constant of 18.6 s-1, slow oscillations in the quiet states are generated, and for rate constant of 25 s-1, a possible cortical network oscillation emerges. As far as I know, this is the first time that the GABA excitatory effect has been integrated into a mean-field cortical model and the discontinuous EEG wave successfully simulated in a qualitative way.

text: Investigation and Modelling of Fetal Sheep Maturation In this thesis, I study the maturational changes of the fetal sheep ECoG (electrocorticogram) in its third-trimester of gestation (95-140 days of gestation), investigate three continuum models for electrical behaviour of the cortex, and tune the parameters in one of these models to generate the discontinuous EEG waves in the immature cortex. Visual inspection of the ECoG time-series shows that the third-trimester of fetal sheep is comprised of two stages: early third-trimester characterised by bursting activity separated by silent intervals, and late third-trimester with well-defined SWS (slow wave sleep) and REM (rapid eye movement) sleep states. For the late third-trimester, the results of power, correlation time, and SVD (singular value decomposition) entropy analysis demonstrate that the sleep state change is a cortical phase transition—with SWS-to-REM transition being a first-order transition, and REM-to-SWS second-order. Further analyses by correlation time, SVD entropy, and spectral edge frequency display that the differentiation of the two distinct SWS and REM sleep states occurs at about 125 dGA (day gestational age). Spectral analysis divides the third-trimester into four stages in terms of the frequency and amplitude variations of the major resonances. Spindle-like resonances only occur in the first stage. A power surge is observed immediately prior to the emergence of the two sleep states. Most significant changes of the spectrum occur during the fourth stage for both SWS (in amplitude) and REM (in frequency) sleep states. For the modelling of the immature cortex, different theoretical descriptions of cortical behaviour are investigated, including the ccf (cortical column field) model of J. J. Wright, and the Waikato cortical model. For the ccf model at centimetric scale, the time-series, fluctuation power, power law relation, gamma oscillation, phase relation between excitatory and inhibitory elements, power spectral density, and spatial Fourier spectrum are quantified from numerical simulations. From these simulations, I determined that the physiologically sophisticated ccf model is too large and unwieldy for easy tuning to match the electrical response of the immature cortex. The Waikato near-far fast-soma model is constructed by incorporating the back-propagation effect of the action potential into the Waikato fast-soma model, state equations are listed and stability prediction are performed by varying the gap junction diffusion strength, subcortical drive, and the rate constants of the near- and far-dendritic tree. In the end, I selected the classic and simpler Waikato slow-soma mean-field model to use for my immature cortex simulations. Model parameters are customised based on the physiology of the immature cortex, including GABA (an inhibitory neurotransmitter in adult) excitatory effect, number of synaptic connections, and rate constants of the IPSPs (inhibitory postsynaptic potential). After hyperpolarising the neuron resting voltage sufficiently to cause the immature inhibitory neuron to act as an excitatory agent, I alter the rate constant of the IPSP, and study the stability of the immature cortex. The bursting activity and quiet states of the discontinuous EEG are simulated and the gap junction diffusion effect in the immature cortex is also examined. For a rate constant of 18.6 s-1, slow oscillations in the quiet states are generated, and for rate constant of 25 s-1, a possible cortical network oscillation emerges. As far as I know, this is the first time that the GABA excitatory effect has been integrated into a mean-field cortical model and the discontinuous EEG wave successfully simulated in a qualitative way.

year: 2010

title: Te Rau Puawai 2002-2004: An evaluation

authors: Nikora, Linda Waimarie

subjects: evaluation

abstract: Established in 1999 as a joint workforce initiative between the former Health Funding Authority and Massey University, Te Rau Puawai aimed to support 100 Maori students to graduate with mental health qualifications within a five year period. The goal of Te Rau Puawai is to contribute to the building of capacity for Maori in the mental health workforce. The programme exceeded its performance expectations in the first two years (1999-2001) with 56 bursars completing their qualifications. Bursars achieved an 80% pass rate compared with 65% for all students at Massey University as a whole. In 2004, this pass rate has continued, a significant achievement in light of increasing numbers of bursars being accepted and many without previously studying at the tertiary level.

In 2001 the Maori & Psychology Research Unit (MPRU) at the University of Waikato undertook an evaluation of Te Rau Puawai reporting on the programme's success and identifying any barriers the programme needed to address. The 2002 evaluation report outlines critical success factors and recommendations for improvement. In 2003 Te Rau Puawai negotiated further funding from the Mental Health Directorate (MeHD) of the Ministry of Health under the Mental Health Workforce Development Strategy (2002). Workforce development is critical in building capacity and capability in the mental health workforce to increase appropriately skilled workers required to meet the mental health needs of Maori communities. In 2004 the Ministry of Health requested a follow-up evaluation to provide a descriptive record of programme activities and progress from April 2002 to December 2004. This report provides an overview of Te Rau Puawai activities between 2002 and 2004; the progress and contributions made by bursars to the mental health workforce; and a reassessment of the programme's critical success factors.

text: Te Rau Puawai 2002-2004: An evaluation Established in 1999 as a joint workforce initiative between the former Health Funding Authority and Massey University, Te Rau Puawai aimed to support 100 Maori students to graduate with mental health qualifications within a five year period. The goal of Te Rau Puawai is to contribute to the building of capacity for Maori in the mental health workforce. The programme exceeded its performance expectations in the first two years (1999-2001) with 56 bursars completing their qualifications. Bursars achieved an 80% pass rate compared with 65% for all students at Massey University as a whole. In 2004, this pass rate has continued, a significant achievement in light of increasing numbers of bursars being accepted and many without previously studying at the tertiary level.

In 2001 the Maori & Psychology Research Unit (MPRU) at the University of Waikato undertook an evaluation of Te Rau Puawai reporting on the programme's success and identifying any barriers the programme needed to address. The 2002 evaluation report outlines critical success factors and recommendations for improvement. In 2003 Te Rau Puawai negotiated further funding from the Mental Health Directorate (MeHD) of the Ministry of Health under the Mental Health Workforce Development Strategy (2002). Workforce development is critical in building capacity and capability in the mental health workforce to increase appropriately skilled workers required to meet the mental health needs of Maori communities. In 2004 the Ministry of Health requested a follow-up evaluation to provide a descriptive record of programme activities and progress from April 2002 to December 2004. This report provides an overview of Te Rau Puawai activities between 2002 and 2004; the progress and contributions made by bursars to the mental health workforce; and a reassessment of the programme's critical success factors.

year: 2005-01-01