title: Toward multi-objective optimisation for Lake Taupo water level managment

authors: Bardsley, W. Earl

subjects: Lake Taupo

abstract: A multi-goal optimisation strategy may provide a basis for Lake Taupō water management. This involves defining an agreed ‘optimal zone’ of lake levels which are away from both high and low levels. The aim of water releases to the Waikato River would be to maximise the duration that lake levels are within the optimal zone, while also seeking to meet other, possibly conflicting, goals such as optimal hydro power operation.
A sense of how a multi-goal model could operate is given, by considering a simple dual-goal linear programming model that manages Taupō water levels on a daily time step, optimised toward (i) hydro power income and (ii) water level in the optimal zone. The model serves as an illustration only but the approach is readily capable of being expanded to a full model that includes further goals and constraints.

text: Toward multi-objective optimisation for Lake Taupo water level managment A multi-goal optimisation strategy may provide a basis for Lake Taupō water management. This involves defining an agreed ‘optimal zone’ of lake levels which are away from both high and low levels. The aim of water releases to the Waikato River would be to maximise the duration that lake levels are within the optimal zone, while also seeking to meet other, possibly conflicting, goals such as optimal hydro power operation.
A sense of how a multi-goal model could operate is given, by considering a simple dual-goal linear programming model that manages Taupō water levels on a daily time step, optimised toward (i) hydro power income and (ii) water level in the optimal zone. The model serves as an illustration only but the approach is readily capable of being expanded to a full model that includes further goals and constraints.

year: 2019

title: Aspects of the biology of the freshwater crayfish Paranephrops Planifrons White in Lake Rotoiti

authors: Devcich, Alan A.

subjects: Freshwater Crayfish

abstract: Aspects of the biology of Paranephrops planifrons White in Lake Rotoiti were studied and comparisons made with P. planifrons inhabiting neighbouring Lakes Okataina and Rotorua. Two migrations upwards occurred, in spring and summer, the first thought to be associated with temperature and egg-hatching, the second due to hypolimnetic deoxygenation. Hence in late summer and early autumn crayfish were concentrated above and within the thermocline. Movement downwards occurred in early winter, after lake turnover and this was thought to be associated with gonad maturation, induced by low temperatures and shorter photoperiod. During winter crayfish distributed evenly over the lake floor. There were two breeding seasons, in late autumn and winter (the larger of the two) and late spring and summer. Lake Okataina P. planifrons bred annually, during late autumn and winter, and showed no apparent seasonal movement patterns. Moulting occurred during the warmer months.

Average densities of 0.030, 0.014 and 0.003 adult crayfish/m. ² were calculated for Lakes Rotoiti, Okataina and Rotorua respectively. In these populations a broad inverse relationship was found between density and mean population size, for individual sizes were small in Wright’s Bay, Rotoiti compared to those in Lakes Okataina and Rotorua and other parts of Rotoiti. Sizes of males and females were not significantly different and mean size was constant throughout all depths. Sex ratios of 1.9:1 and 2.3:1 in favour of males were found in Lakes Rotoiti and Okataina respectively. Stomach content analyses revealed that the diet was mainly detritus, but also included animal remains and vascular plant material. Sediment analyses showed that food quality was essentially the same at all depths. Feeding was continuous at depths greater than 20m. but in shallower water it took place only at night. It appeared that P. planifrons does not display homing and the home range is extensive. Observations revealed that territorial behaviour occurred and males were not dominant over females, although larger crayfish were dominant over smaller animals.

text: Aspects of the biology of the freshwater crayfish Paranephrops Planifrons White in Lake Rotoiti Aspects of the biology of Paranephrops planifrons White in Lake Rotoiti were studied and comparisons made with P. planifrons inhabiting neighbouring Lakes Okataina and Rotorua. Two migrations upwards occurred, in spring and summer, the first thought to be associated with temperature and egg-hatching, the second due to hypolimnetic deoxygenation. Hence in late summer and early autumn crayfish were concentrated above and within the thermocline. Movement downwards occurred in early winter, after lake turnover and this was thought to be associated with gonad maturation, induced by low temperatures and shorter photoperiod. During winter crayfish distributed evenly over the lake floor. There were two breeding seasons, in late autumn and winter (the larger of the two) and late spring and summer. Lake Okataina P. planifrons bred annually, during late autumn and winter, and showed no apparent seasonal movement patterns. Moulting occurred during the warmer months.

Average densities of 0.030, 0.014 and 0.003 adult crayfish/m. ² were calculated for Lakes Rotoiti, Okataina and Rotorua respectively. In these populations a broad inverse relationship was found between density and mean population size, for individual sizes were small in Wright’s Bay, Rotoiti compared to those in Lakes Okataina and Rotorua and other parts of Rotoiti. Sizes of males and females were not significantly different and mean size was constant throughout all depths. Sex ratios of 1.9:1 and 2.3:1 in favour of males were found in Lakes Rotoiti and Okataina respectively. Stomach content analyses revealed that the diet was mainly detritus, but also included animal remains and vascular plant material. Sediment analyses showed that food quality was essentially the same at all depths. Feeding was continuous at depths greater than 20m. but in shallower water it took place only at night. It appeared that P. planifrons does not display homing and the home range is extensive. Observations revealed that territorial behaviour occurred and males were not dominant over females, although larger crayfish were dominant over smaller animals.

year: 1974

title: Wāhine Whaiora: Māori Women's Experiences of Bipolar Disorder and their Pathways to Recovery

authors: Harris, Parewahaika Erenora Te Korowhiti

subjects: Māori health

abstract: This research examines the unique, lived experiences of wāhine Māori (Māori women) who have been diagnosed with bipolar affective disorder and who are currently living ‘well’. Recent literature indicates that Māori present at higher rates than non-Māori with bipolar disorder. However, there is little qualitative information about the nature of their experiences, as well as sparse detail of the impacts that bipolar has on their everyday living.

The purpose of this research is to highlight Māori women’s experiences of bipolar disorder from initial presentation and assessment through to diagnosis, treatment and recovery.  It focuses on the impact bipolar disorder has on women’s relationships with their tamariki (children), whānau (family), and partners, while also exploring social and personal impacts, help-seeking patterns, and stories of recovery.
This research heard the stories of 11 wāhine Māori using a narrative-storying technique to allow wāhine to share their unique experiences as they recalled them. A thematic analysis was then used to identify key themes that depicted their journeys of:

•	Illness and symptom presentation;
•	Consequences and impacts of bipolar disorder; 
•	Support and help-seeking; and
•	Wellness and recovery.

The intent of this research is to create an awareness of the nature of bipolar disorder as it affects wāhine Māori. It endeavours to expose the experiences they have encountered and their aspirations to be better supported by whānau, and community organisations in their attempts to live active and well lives.

text: Wāhine Whaiora: Māori Women's Experiences of Bipolar Disorder and their Pathways to Recovery This research examines the unique, lived experiences of wāhine Māori (Māori women) who have been diagnosed with bipolar affective disorder and who are currently living ‘well’. Recent literature indicates that Māori present at higher rates than non-Māori with bipolar disorder. However, there is little qualitative information about the nature of their experiences, as well as sparse detail of the impacts that bipolar has on their everyday living.

The purpose of this research is to highlight Māori women’s experiences of bipolar disorder from initial presentation and assessment through to diagnosis, treatment and recovery.  It focuses on the impact bipolar disorder has on women’s relationships with their tamariki (children), whānau (family), and partners, while also exploring social and personal impacts, help-seeking patterns, and stories of recovery.
This research heard the stories of 11 wāhine Māori using a narrative-storying technique to allow wāhine to share their unique experiences as they recalled them. A thematic analysis was then used to identify key themes that depicted their journeys of:

•	Illness and symptom presentation;
•	Consequences and impacts of bipolar disorder; 
•	Support and help-seeking; and
•	Wellness and recovery.

The intent of this research is to create an awareness of the nature of bipolar disorder as it affects wāhine Māori. It endeavours to expose the experiences they have encountered and their aspirations to be better supported by whānau, and community organisations in their attempts to live active and well lives.

year: 2014