title: Blu-ray cytometer

authors: Albugami, Naser

abstract: The flow cytometers are one of the most powerful devices used to measure the properties of individual particles passing through a sensing region. In this thesis, a low cost cytometer using a Blu-ray pickup is analysed and further developed. This includes the characterisation of the existing system and its performance as well as the evaluation of count rate for different flow rates and focuses. Based on that, the best parameters for measurement conditions have been determined. The system was set up for forward scatter as well as for fluorescence, both were to be measured at the same time and it was found that both could be recorded and counted. In addition, it was found that fluorescing particles can give a fluorescent count as well as scatter count and it was noticed that different sizes of non-fluorescent particles can produce scatter count. The count rate for a mixture of fluorescent and non-fluorescent particles was measured. This required the installation of two different amplifiers (for fluorescent and non-fluorescent particles) and building a new LabView program containing two channels.

In a later part of the thesis, the system was improved to progress towards a setup of avalanche photodiode as detector for forward scattering as well as fluorescence. This gives a very good counting accuracy of 90% at speed of 10μl/s. However, this counting accuracy drops to 80% at speed of 1μl/s when mixing fluorescent and non-fluorescent particles. The counting accuracy is the ratio (in percent) of the measured count to the actual one. As a new detection approach, a beam stop was installed in front of the photo detector so scattered laser light from particles was detected instead of a reduction of laser intensity. This part of the project proves Mie theory which states that the the forward scattered light is in the forward direction. To double check this result, a beam pass was installed in front of the photo detector and the calculated percentage of counting accuracy was very close to the one without a beam stop. It was also checked that the system was capable of detection fluorescent particle after the installation of a high bass filter which passes fluorescent wavelength signals (green) and blocks the blue ray signals. Finally, it was found that this system is able to detect small size particles, such as 1μm particles and to distinguish between 1μm and 10μm particles.

text: Blu-ray cytometer The flow cytometers are one of the most powerful devices used to measure the properties of individual particles passing through a sensing region. In this thesis, a low cost cytometer using a Blu-ray pickup is analysed and further developed. This includes the characterisation of the existing system and its performance as well as the evaluation of count rate for different flow rates and focuses. Based on that, the best parameters for measurement conditions have been determined. The system was set up for forward scatter as well as for fluorescence, both were to be measured at the same time and it was found that both could be recorded and counted. In addition, it was found that fluorescing particles can give a fluorescent count as well as scatter count and it was noticed that different sizes of non-fluorescent particles can produce scatter count. The count rate for a mixture of fluorescent and non-fluorescent particles was measured. This required the installation of two different amplifiers (for fluorescent and non-fluorescent particles) and building a new LabView program containing two channels.

In a later part of the thesis, the system was improved to progress towards a setup of avalanche photodiode as detector for forward scattering as well as fluorescence. This gives a very good counting accuracy of 90% at speed of 10μl/s. However, this counting accuracy drops to 80% at speed of 1μl/s when mixing fluorescent and non-fluorescent particles. The counting accuracy is the ratio (in percent) of the measured count to the actual one. As a new detection approach, a beam stop was installed in front of the photo detector so scattered laser light from particles was detected instead of a reduction of laser intensity. This part of the project proves Mie theory which states that the the forward scattered light is in the forward direction. To double check this result, a beam pass was installed in front of the photo detector and the calculated percentage of counting accuracy was very close to the one without a beam stop. It was also checked that the system was capable of detection fluorescent particle after the installation of a high bass filter which passes fluorescent wavelength signals (green) and blocks the blue ray signals. Finally, it was found that this system is able to detect small size particles, such as 1μm particles and to distinguish between 1μm and 10μm particles.

year: 2012

title: Lecturer--student views on successful online learning environments.

authors: Khoo, Elaine G.L.

subjects: online teaching

abstract: While many are enthusiastic about the promises of online learning as a flexible form of learning, others are cautious and concerned with the quality of teaching and learning rendered in such environments. In response, this article reports on the findings of a study conducted to better understand the issues related to the nature of learning in online environments and how learning in such environments can be successfully facilitated. Ten online lecturers and their students were surveyed at the Faculty of Education, University of Waikato. Successful online teaching and learning was characterised as a social interactive process such as that embodied within learning communities. Teaching practices and responsibilities associated with four lecturer roles were crucial to this process-pedagogical, managerial, social and technological. Considering these multiple roles is argued to be a productive framework in enabling online lecturers to understand and act on each role's required responsibility, tasks and practices and adapt them to their particular teaching context.

text: Lecturer--student views on successful online learning environments. While many are enthusiastic about the promises of online learning as a flexible form of learning, others are cautious and concerned with the quality of teaching and learning rendered in such environments. In response, this article reports on the findings of a study conducted to better understand the issues related to the nature of learning in online environments and how learning in such environments can be successfully facilitated. Ten online lecturers and their students were surveyed at the Faculty of Education, University of Waikato. Successful online teaching and learning was characterised as a social interactive process such as that embodied within learning communities. Teaching practices and responsibilities associated with four lecturer roles were crucial to this process-pedagogical, managerial, social and technological. Considering these multiple roles is argued to be a productive framework in enabling online lecturers to understand and act on each role's required responsibility, tasks and practices and adapt them to their particular teaching context.

year: 2010

title: Pātangaroa: Co-developing management strategies for a starfish outbreak in Ōhiwa Harbour

authors: Ranapia, Megan

subjects: marine management

abstract: The management of marine environments often prioritises scientific information to address complex marine social-ecological issues. However, there is a wealth of learning to be gained from Indigenous people who have generated place-based intergenerational understandings and cultural ethics and practices. Consequently, Indigenous knowledge alongside science can offer better insights, holistic understanding, sustainable management strategies and greater sources of evidence. This research is located in Aotearoa New Zealand and engages in mātauranga Māori (Māori knowledge) alongside marine ecology as an appropriate method for contemporary marine research and management. The thesis study focused on Ōhiwa Harbour, aiming to co-develop a starfish management action plan (SMAP) with local iwi (tribe) Ngāti Awa and other affiliated iwi, district councils and regional council to address the overabundant starfish (species: Coscinasterias muricata and Patiriella regularis). By engaging in transdisciplinary research and collaborative decision-making, this study sought to bridge the gap between Indigenous knowledge and mainstream science, offering lessons for inclusive marine management practices.

To achieve this, I developed and prescribed a co-developed framework actively promoting a mixed-methods approach, inclusive of kaupapa Māori research methodologies, tikanga, participatory design, applied mātauranga ā iwi, quantitative marine scientific field methods and experimental study design. Through the collaborative process, I identified areas of appropriate research aims and methods. This included co-developing a novel starfish trapping methodology sensitive to local ecology and cultural values and an experimental starfish removal study to assist decision-makers in implementing an efficient and effective starfish removal regime as an approach to management.

Results from the field studies showed the efficacy of starfish traps is dependent on environmental conditions, physical characteristics and soaking time (the length of time the trap is left in the water). A soaking time of 48 h maintained the highest starfish catch per unit effort (CPUE) while minimising time to re-bait and reset traps. Observations also indicated an open trap design had less bycatch than a semi-enclosed box trap and could withstand the tidal currents for a longer period. The findings found that bait type did not impact on CPUE. In the starfish removal study, the combined effort of diver removals and trapping produced higher daily catch rates than the single treatments (i.e., diver removals only or trapping only), therefore was themost efficient removal method. The empirical information gathered from the field studies was then used to inform the SMAP and was accepted unanimously at the highest local/regional co-management level. Furthermore, through the findings I identified future research opportunities that would further close gaps in our knowledge around the best management approaches for a starfish outbreak. These included investigation into the predation impacts of P. regularis on mussel recruitment, identification of alternative restoration sites less susceptible to starfish predation pressures and investigation of potential drivers of the starfish outbreak.

Overall, the acceptance of the SMAP by local iwi/hapū and government authorities underscores the success of the collaborative approach. The collaborative process not only addresses the immediate concerns of starfish infestation but contributed to the broader goal of supporting kaitiakitanga (active guardianship) responsibilities and promoting Indigenous perspectives in marine management. This thesis demonstrates and recommends a new approach to starfish management in coastal marine areas using both marine science and mātauranga Māori understandings, practices and ethics, furthermore, it demonstrates the commitment to the inclusion of multiple knowledge systems and involvement of communities.

text: Pātangaroa: Co-developing management strategies for a starfish outbreak in Ōhiwa Harbour The management of marine environments often prioritises scientific information to address complex marine social-ecological issues. However, there is a wealth of learning to be gained from Indigenous people who have generated place-based intergenerational understandings and cultural ethics and practices. Consequently, Indigenous knowledge alongside science can offer better insights, holistic understanding, sustainable management strategies and greater sources of evidence. This research is located in Aotearoa New Zealand and engages in mātauranga Māori (Māori knowledge) alongside marine ecology as an appropriate method for contemporary marine research and management. The thesis study focused on Ōhiwa Harbour, aiming to co-develop a starfish management action plan (SMAP) with local iwi (tribe) Ngāti Awa and other affiliated iwi, district councils and regional council to address the overabundant starfish (species: Coscinasterias muricata and Patiriella regularis). By engaging in transdisciplinary research and collaborative decision-making, this study sought to bridge the gap between Indigenous knowledge and mainstream science, offering lessons for inclusive marine management practices.

To achieve this, I developed and prescribed a co-developed framework actively promoting a mixed-methods approach, inclusive of kaupapa Māori research methodologies, tikanga, participatory design, applied mātauranga ā iwi, quantitative marine scientific field methods and experimental study design. Through the collaborative process, I identified areas of appropriate research aims and methods. This included co-developing a novel starfish trapping methodology sensitive to local ecology and cultural values and an experimental starfish removal study to assist decision-makers in implementing an efficient and effective starfish removal regime as an approach to management.

Results from the field studies showed the efficacy of starfish traps is dependent on environmental conditions, physical characteristics and soaking time (the length of time the trap is left in the water). A soaking time of 48 h maintained the highest starfish catch per unit effort (CPUE) while minimising time to re-bait and reset traps. Observations also indicated an open trap design had less bycatch than a semi-enclosed box trap and could withstand the tidal currents for a longer period. The findings found that bait type did not impact on CPUE. In the starfish removal study, the combined effort of diver removals and trapping produced higher daily catch rates than the single treatments (i.e., diver removals only or trapping only), therefore was themost efficient removal method. The empirical information gathered from the field studies was then used to inform the SMAP and was accepted unanimously at the highest local/regional co-management level. Furthermore, through the findings I identified future research opportunities that would further close gaps in our knowledge around the best management approaches for a starfish outbreak. These included investigation into the predation impacts of P. regularis on mussel recruitment, identification of alternative restoration sites less susceptible to starfish predation pressures and investigation of potential drivers of the starfish outbreak.

Overall, the acceptance of the SMAP by local iwi/hapū and government authorities underscores the success of the collaborative approach. The collaborative process not only addresses the immediate concerns of starfish infestation but contributed to the broader goal of supporting kaitiakitanga (active guardianship) responsibilities and promoting Indigenous perspectives in marine management. This thesis demonstrates and recommends a new approach to starfish management in coastal marine areas using both marine science and mātauranga Māori understandings, practices and ethics, furthermore, it demonstrates the commitment to the inclusion of multiple knowledge systems and involvement of communities.

year: 2025-05