title: The Effects of Turbidity on Suspension Feeding Bivalves

authors: Teaioro, Iannang

abstract: This thesis aimed to describe the relationship between suspended sediment concentration stimulating the turbidity caused by natural events or human activities, and the feeding behaviour and energetics of scallops (Pecten novaezelandiae), mussels (Perna canaliculus) and pipis (Paphies australis). A wide range of suspended sediment concentration with different organic content was used. In experiment 1, sediment with high organic content added to natural seston (12 - 733 mg 1−1) was used, whereas in experiment 2, sediment with very low organic content added to natural seston (20 - 196 mg 1−1) was used. Scallops enhanced the organic content of ingested matter by producing pseudofaeces with low organic content when the diet organic content had been diluted to~ 14% in both experiments. For the diet with high organic content, the clearance rate (the volume of water cleared of suspended particles) decreased with increasing sediment concentration (12 - 733 mg 1−1) ,but when the diet was composed of low organic content, clearance rate increased up to a concentration limit of 120-140 mg 1−1. Positive scope for growth was attained until suspended sediment concentration exceeded 190 mg 1−1. Similarly, mussels also enhanced the organic content of ingested matter by producing pseudofaeces with low organic content when the diet organic content had been diluted to ~ 16% in both experiments. The enhancement of ingested organic fraction was accomplished by two different feeding behaviours. When the diet had high organic content, mussels clear less water, reduce the volume of pseudofaeces produced, and reduce the amount of energy expired via low respiration rates. Consequently, the net energy gained was uniformly high as sediment concentrations increased to 322 mg 1−1. The low organic diet prompted high clearance rates and increase in pseudofaeces production as sediment concentration increased. Due to high feeding activities, energy expenditure was also high which was reflected in a low net energy gain. Pipis can only feed efficiently at very low sediment concentrations (<39 mg 1−1) in experiment I and 20.1 mg 1−1 in experiment 2). Beyond these values, pipis were unable to compensate for increased sediment concentration and therefore had very low scope for growth. 
From these results it was concluded that preferential selection of organic particles before ingestion, adjusting clearance and respiration rates, within limits, are the key elements that enable scallops and mussels to cope with high turbidity levels. Pipis have a low tolerance level to turbidity. 
The second aim of the study was to investigate the effects of resuspended sediments caused by dredging on seston quality (organic content and pigment concentration) and quantity. This was accomplished through water sampling at various places while dredging was in operation. The results indicated that suspended sediments caused by dredging had no significant effect on the seston quality and quantity, in relation to the seston characteristics observed naturally.

text: The Effects of Turbidity on Suspension Feeding Bivalves This thesis aimed to describe the relationship between suspended sediment concentration stimulating the turbidity caused by natural events or human activities, and the feeding behaviour and energetics of scallops (Pecten novaezelandiae), mussels (Perna canaliculus) and pipis (Paphies australis). A wide range of suspended sediment concentration with different organic content was used. In experiment 1, sediment with high organic content added to natural seston (12 - 733 mg 1−1) was used, whereas in experiment 2, sediment with very low organic content added to natural seston (20 - 196 mg 1−1) was used. Scallops enhanced the organic content of ingested matter by producing pseudofaeces with low organic content when the diet organic content had been diluted to~ 14% in both experiments. For the diet with high organic content, the clearance rate (the volume of water cleared of suspended particles) decreased with increasing sediment concentration (12 - 733 mg 1−1) ,but when the diet was composed of low organic content, clearance rate increased up to a concentration limit of 120-140 mg 1−1. Positive scope for growth was attained until suspended sediment concentration exceeded 190 mg 1−1. Similarly, mussels also enhanced the organic content of ingested matter by producing pseudofaeces with low organic content when the diet organic content had been diluted to ~ 16% in both experiments. The enhancement of ingested organic fraction was accomplished by two different feeding behaviours. When the diet had high organic content, mussels clear less water, reduce the volume of pseudofaeces produced, and reduce the amount of energy expired via low respiration rates. Consequently, the net energy gained was uniformly high as sediment concentrations increased to 322 mg 1−1. The low organic diet prompted high clearance rates and increase in pseudofaeces production as sediment concentration increased. Due to high feeding activities, energy expenditure was also high which was reflected in a low net energy gain. Pipis can only feed efficiently at very low sediment concentrations (<39 mg 1−1) in experiment I and 20.1 mg 1−1 in experiment 2). Beyond these values, pipis were unable to compensate for increased sediment concentration and therefore had very low scope for growth. 
From these results it was concluded that preferential selection of organic particles before ingestion, adjusting clearance and respiration rates, within limits, are the key elements that enable scallops and mussels to cope with high turbidity levels. Pipis have a low tolerance level to turbidity. 
The second aim of the study was to investigate the effects of resuspended sediments caused by dredging on seston quality (organic content and pigment concentration) and quantity. This was accomplished through water sampling at various places while dredging was in operation. The results indicated that suspended sediments caused by dredging had no significant effect on the seston quality and quantity, in relation to the seston characteristics observed naturally.

year: 1999

title: A diversity-aware model for majority vote ensemble accuracy

authors: Lim, Nick Jin Sean

subjects: Science & Technology

abstract: Ensemble classifiers are a successful and popular approach for classification, and are frequently found to have better generalization performance than single models in practice. Although it is widely recognized that ‘diversity’ between ensemble members is important in achieving these performance gains, for classification ensembles it is not widely understood which diversity measures are most predictive of ensemble performance, nor how large an ensemble should be for a particular application. In this paper, we explore the predictive power of several common diversity measures and show – with extensive experiments – that contrary to earlier work that finds no clear link between these diversity measures (in isolation) and ensemble accuracy instead by using the ρ diversity measure of Sneath and Sokal as an estimator for the dispersion parameter of a Polya-Eggenberger distribution we can predict, independently of the choice of base classifier family, the accuracy of a majority vote classifier ensemble ridiculously well. We discuss our model and some implications of our findings – such as diversity-aware (non-greedy) pruning of a majority-voting ensemble.

text: A diversity-aware model for majority vote ensemble accuracy Ensemble classifiers are a successful and popular approach for classification, and are frequently found to have better generalization performance than single models in practice. Although it is widely recognized that ‘diversity’ between ensemble members is important in achieving these performance gains, for classification ensembles it is not widely understood which diversity measures are most predictive of ensemble performance, nor how large an ensemble should be for a particular application. In this paper, we explore the predictive power of several common diversity measures and show – with extensive experiments – that contrary to earlier work that finds no clear link between these diversity measures (in isolation) and ensemble accuracy instead by using the ρ diversity measure of Sneath and Sokal as an estimator for the dispersion parameter of a Polya-Eggenberger distribution we can predict, independently of the choice of base classifier family, the accuracy of a majority vote classifier ensemble ridiculously well. We discuss our model and some implications of our findings – such as diversity-aware (non-greedy) pruning of a majority-voting ensemble.

year: 2020

title: Uia ngā pou o te whare ask the posts of the whare:  (Re)storying the whare in curriculum

authors: Heaton, Sharyn

subjects: Whare

abstract: This research investigated the construction of whare tapawhā discourses in national curricula since 1999 and (re)presents other Māori perspectives of how a whare (house, building, school of learning, curriculum) can be known. I explored the constitutions and subjectivities of a whare and its relationship to hauora, well-being and its dimensions. The central questions raised in this thesis are how has a whare model of hauora, well-being been signified within dominant education texts, and how could a Māori (re)envisioning of a whare assist future Māori-medium hauora learning area developments? Further elaborations on how a whare can be known and its potential contribution to future hauora learning area developments take priority as a focus within this thesis.
For this study, I developed ngā pou whakaaro, a theoretical, conceptual, and methodological framework characterised by unfolding layers of awareness (and reflection) that I applied when thinking and reading through texts. Texts included primary and secondary literature such as curricula policy, hauora redevelopment wānanga (meetings, discussions) notes, hauora redevelopment video, hauora Ministry of Education milestone reports and interview transcripts. Within these texts, I searched for significations and signifiers of how the whare tapawhā model of hauora, well-being or a whare had been (re)presented. I searched for what was clearly evident and the assumptions made about a whare, and critiqued omissions of what had not yet been said. These gaps provided an opportunity to rewrite and reproduce other texts. 
I initially critiqued dominant representations of the whare tapawhā model of hauora, well-being, as evident in English-medium policy texts. I argue that the whare tapawhā model and its nuances in national curricula and compulsory schooling are not only driven by education imperatives, such as the valuing of the Māori language and knowledge in compulsory schooling, but are also assimilative in that the knowledge presented is simplistic and the understandings align more with Eurocentric ideals of well-being, albeit in the Māori language. I show that simplified significations of a whare in educational discourse shape the fictions that the texts seek to represent.
And then, in reading otherwise (Caputo, 1997, p. 62), I examined other texts about a whare and its nuances beyond what is currently known in curricula. I interviewed two Māori pouako (teachers), one Māori-medium curriculum developer, a health practitioner, a kairongoā (healer), and two tohunga whakairo (master carvers) to draw out the possibilities that exist for (re)presenting another Māori perspective of a whare. This space provided an opportunity to transgress from how the whare tapawhā model of hauora, well-being has been represented in curricula in Aotearoa. 
The main ideas that emerged from the interviews and the process of reflecting on the responses of the poukōrero (interview participants) provoked thinking about the possibilities of how in-depth understandings of a whare could support a (re)envisioning of the potential of a whare in future hauora learning area developments. In order to (re)turn to thinking about the place of mātauranga Māori (Māori ways of knowing), and how a whare can be known and experienced by Māori beyond what is currently (re)presented in curricula, the whare of Mautini Aroaro was examined. 
Representations of a whare may be partial and fragmented, but such representations need to be (re)traced back to their parts and elaborated upon to deepen understandings of the possible contribution that a Māori perspective could offer future Māori-medium hauora learning area re-developments. There is no one way to know a whare, nor does it need to be restricted to pre-determined representations identified in curricula. Through a restoration process, I suggest we engage with people’s experiences of a whare on different terms and (re)claim understandings of a whare as a repository and library for future generations.

text: Uia ngā pou o te whare ask the posts of the whare:  (Re)storying the whare in curriculum This research investigated the construction of whare tapawhā discourses in national curricula since 1999 and (re)presents other Māori perspectives of how a whare (house, building, school of learning, curriculum) can be known. I explored the constitutions and subjectivities of a whare and its relationship to hauora, well-being and its dimensions. The central questions raised in this thesis are how has a whare model of hauora, well-being been signified within dominant education texts, and how could a Māori (re)envisioning of a whare assist future Māori-medium hauora learning area developments? Further elaborations on how a whare can be known and its potential contribution to future hauora learning area developments take priority as a focus within this thesis.
For this study, I developed ngā pou whakaaro, a theoretical, conceptual, and methodological framework characterised by unfolding layers of awareness (and reflection) that I applied when thinking and reading through texts. Texts included primary and secondary literature such as curricula policy, hauora redevelopment wānanga (meetings, discussions) notes, hauora redevelopment video, hauora Ministry of Education milestone reports and interview transcripts. Within these texts, I searched for significations and signifiers of how the whare tapawhā model of hauora, well-being or a whare had been (re)presented. I searched for what was clearly evident and the assumptions made about a whare, and critiqued omissions of what had not yet been said. These gaps provided an opportunity to rewrite and reproduce other texts. 
I initially critiqued dominant representations of the whare tapawhā model of hauora, well-being, as evident in English-medium policy texts. I argue that the whare tapawhā model and its nuances in national curricula and compulsory schooling are not only driven by education imperatives, such as the valuing of the Māori language and knowledge in compulsory schooling, but are also assimilative in that the knowledge presented is simplistic and the understandings align more with Eurocentric ideals of well-being, albeit in the Māori language. I show that simplified significations of a whare in educational discourse shape the fictions that the texts seek to represent.
And then, in reading otherwise (Caputo, 1997, p. 62), I examined other texts about a whare and its nuances beyond what is currently known in curricula. I interviewed two Māori pouako (teachers), one Māori-medium curriculum developer, a health practitioner, a kairongoā (healer), and two tohunga whakairo (master carvers) to draw out the possibilities that exist for (re)presenting another Māori perspective of a whare. This space provided an opportunity to transgress from how the whare tapawhā model of hauora, well-being has been represented in curricula in Aotearoa. 
The main ideas that emerged from the interviews and the process of reflecting on the responses of the poukōrero (interview participants) provoked thinking about the possibilities of how in-depth understandings of a whare could support a (re)envisioning of the potential of a whare in future hauora learning area developments. In order to (re)turn to thinking about the place of mātauranga Māori (Māori ways of knowing), and how a whare can be known and experienced by Māori beyond what is currently (re)presented in curricula, the whare of Mautini Aroaro was examined. 
Representations of a whare may be partial and fragmented, but such representations need to be (re)traced back to their parts and elaborated upon to deepen understandings of the possible contribution that a Māori perspective could offer future Māori-medium hauora learning area re-developments. There is no one way to know a whare, nor does it need to be restricted to pre-determined representations identified in curricula. Through a restoration process, I suggest we engage with people’s experiences of a whare on different terms and (re)claim understandings of a whare as a repository and library for future generations.

year: 2022