title: Predicting chitosan particle size produced by electrohydrodynamic atomization

authors: Hu, Jung-Feng

subjects: chitosan

abstract: The effect of processing variables on the size of chitosan nanoparticles produced by electrohydrodynamic atomization was investigated. The size was strongly affected by process variables such as surface tension, conductivity and flow rate of chitosan solution, applied voltage and distance between the electrodes. A simple scaling law to quantitatively correlate the droplet size and process variables was developed by dimensional analysis and used to predict the diameter of particles produced under a given set of conditions. The model predictions agreed reasonably well with the experimental results.

text: Predicting chitosan particle size produced by electrohydrodynamic atomization The effect of processing variables on the size of chitosan nanoparticles produced by electrohydrodynamic atomization was investigated. The size was strongly affected by process variables such as surface tension, conductivity and flow rate of chitosan solution, applied voltage and distance between the electrodes. A simple scaling law to quantitatively correlate the droplet size and process variables was developed by dimensional analysis and used to predict the diameter of particles produced under a given set of conditions. The model predictions agreed reasonably well with the experimental results.

year: 2012

title: The role of thermal tolerance in biological invasion

authors: Wilde, Margot

abstract: Biological invasion and climate change are among the greatest threats to biodiversity currently. Several factors influence what makes a successful invasive species. Among these is the thermal tolerance of the invasive species. An organism’s thermal physiology underpins many aspects of its life, including the habitats in which it can survive, its reproduction and its development. Climate change is increasing global average temperatures at an unprecedented pace, which is increasing thermal stress on virtually all life around the world. These effects are particularly pronounced in ectotherms, which are reliant on environmental temperature to set their body temperature and drive their metabolism. Insects comprise a significant proportion of globally important invasive species. As well as being ectothermic, they have a complex life cycle with a number of developmental stages, all of which may be influenced by environmental temperatures. Invasive species can often tolerate or adapt to a broad range of environmental conditions. They may therefore be expected to have a broader thermal tolerance than their native counterparts, and than other invasives that have a narrower invaded range.  

This research used a blowfly model to investigate how thermal tolerance differed across temperatures, using a static temperature assay to measure thermal knockdown time. Key foci included the effects of both developmental heat acclimation and adult heat tolerance on thermal performance.  In Chapter 2, variation in adult heat tolerance was assessed across three temperatures (41℃, 42℃, 43℃) in five blowfly species invasive to New Zealand. I found that the two more globally invasive species in the study exhibited higher heat tolerance than the three less invasive Calliphora species, whose native ranges are generally more temperate. In Chapter 3, the effect of developmental temperature on adult knockdown time in a single species (Calliphora stygia) was assessed. I showed that C. stygia reared at the lowest temperature (18℃) had the highest knockdown time and the smallest body size, while those reared at 26℃ 1 exhibited  the shortest knockdown time and an intermediate body size, with those reared at 22℃ being the largest.   

Collectively, my results indicate that adult heat tolerance varies between invasive blowfly species, but that developmental acclimation temperature may not have a significant effect on adult heat tolerance. Given the increasing global temperatures seen with climate change, the effects of invasive species are likely to increase, with some species likely to do better than others in a warming world. Thermal performance will undoubtedly play a role in filtering out the ‘winners’ and ‘losers’, therefore further research into both heat and cold tolerance in both laboratory and field settings are crucial.

text: The role of thermal tolerance in biological invasion Biological invasion and climate change are among the greatest threats to biodiversity currently. Several factors influence what makes a successful invasive species. Among these is the thermal tolerance of the invasive species. An organism’s thermal physiology underpins many aspects of its life, including the habitats in which it can survive, its reproduction and its development. Climate change is increasing global average temperatures at an unprecedented pace, which is increasing thermal stress on virtually all life around the world. These effects are particularly pronounced in ectotherms, which are reliant on environmental temperature to set their body temperature and drive their metabolism. Insects comprise a significant proportion of globally important invasive species. As well as being ectothermic, they have a complex life cycle with a number of developmental stages, all of which may be influenced by environmental temperatures. Invasive species can often tolerate or adapt to a broad range of environmental conditions. They may therefore be expected to have a broader thermal tolerance than their native counterparts, and than other invasives that have a narrower invaded range.  

This research used a blowfly model to investigate how thermal tolerance differed across temperatures, using a static temperature assay to measure thermal knockdown time. Key foci included the effects of both developmental heat acclimation and adult heat tolerance on thermal performance.  In Chapter 2, variation in adult heat tolerance was assessed across three temperatures (41℃, 42℃, 43℃) in five blowfly species invasive to New Zealand. I found that the two more globally invasive species in the study exhibited higher heat tolerance than the three less invasive Calliphora species, whose native ranges are generally more temperate. In Chapter 3, the effect of developmental temperature on adult knockdown time in a single species (Calliphora stygia) was assessed. I showed that C. stygia reared at the lowest temperature (18℃) had the highest knockdown time and the smallest body size, while those reared at 26℃ 1 exhibited  the shortest knockdown time and an intermediate body size, with those reared at 22℃ being the largest.   

Collectively, my results indicate that adult heat tolerance varies between invasive blowfly species, but that developmental acclimation temperature may not have a significant effect on adult heat tolerance. Given the increasing global temperatures seen with climate change, the effects of invasive species are likely to increase, with some species likely to do better than others in a warming world. Thermal performance will undoubtedly play a role in filtering out the ‘winners’ and ‘losers’, therefore further research into both heat and cold tolerance in both laboratory and field settings are crucial.

year: 2025

title: Maori sustainable development in the 21st Century: The importance of Maori values, strategic planning and information systems

authors: Harmsworth, Garth

subjects: Development studies

abstract: The term ‘sustainable development’ has been widely used since the latter part of the 20th century. The concept implies economic and social development, economic growth, and environmental responsibility in order to sustain improved standards of living based on economic growth, to achieve some form of social equity, and to manage the environment in a sustainable way. Sustainable development should generally be at a rate that allows future generations to meet their needs without causing degradation of the natural environment, and should avoid economic or social decay. The concept has been debated and criticised by many as being ambiguous, untenable, and difficult to achieve, and frequently labelled part of global capitalism. But the concept provides a challenge to all of us, on how to balance economic, social, and cultural goals, while at the same time safeguarding and responsibly managing the environment for future generations. Attempts by indigenous peoples internationally to achieve sustainable development have been based on holistic approaches and frameworks that seek to balance economic, social, cultural and environmental objectives, and these provide effective models for viable sustainable development approaches. Māori Sustainable Development in Aotearoa-New Zealand is a term often used to describe a pathway to Māori autonomy, self-determination, the building of human and social capacity, as part of a strategic direction to capitalise on opportunities in the 21st century. This paper outlines research undertaken between 1998 and 2002 and funded by the Foundation for Research, Science, and Technology (FRST) in the programme “Māori Sustainable Development in Te Puku o Te Ika”, contract UOWX0005, simply referred to as the MSD programme. It focuses on the importance of determining Māori values, a vision, strategic planning and development of information systems as a holistic framework and process method to achieve Māori sustainable development.

text: Maori sustainable development in the 21st Century: The importance of Maori values, strategic planning and information systems The term ‘sustainable development’ has been widely used since the latter part of the 20th century. The concept implies economic and social development, economic growth, and environmental responsibility in order to sustain improved standards of living based on economic growth, to achieve some form of social equity, and to manage the environment in a sustainable way. Sustainable development should generally be at a rate that allows future generations to meet their needs without causing degradation of the natural environment, and should avoid economic or social decay. The concept has been debated and criticised by many as being ambiguous, untenable, and difficult to achieve, and frequently labelled part of global capitalism. But the concept provides a challenge to all of us, on how to balance economic, social, and cultural goals, while at the same time safeguarding and responsibly managing the environment for future generations. Attempts by indigenous peoples internationally to achieve sustainable development have been based on holistic approaches and frameworks that seek to balance economic, social, cultural and environmental objectives, and these provide effective models for viable sustainable development approaches. Māori Sustainable Development in Aotearoa-New Zealand is a term often used to describe a pathway to Māori autonomy, self-determination, the building of human and social capacity, as part of a strategic direction to capitalise on opportunities in the 21st century. This paper outlines research undertaken between 1998 and 2002 and funded by the Foundation for Research, Science, and Technology (FRST) in the programme “Māori Sustainable Development in Te Puku o Te Ika”, contract UOWX0005, simply referred to as the MSD programme. It focuses on the importance of determining Māori values, a vision, strategic planning and development of information systems as a holistic framework and process method to achieve Māori sustainable development.

year: 2002