title: NZ’s government plans to switch to a circular economy to cut waste and emissions, but it’s going around in the wrong circles

authors: Blumhardt, Hannah

abstract: The New Zealand government is currently developing plans to address two crises — climate change and waste — and to embrace a circular economy. But it has no clear path for how to do this. The resulting muddle is watering down the potential of a circular economy to bring lasting change.

text: NZ’s government plans to switch to a circular economy to cut waste and emissions, but it’s going around in the wrong circles The New Zealand government is currently developing plans to address two crises — climate change and waste — and to embrace a circular economy. But it has no clear path for how to do this. The resulting muddle is watering down the potential of a circular economy to bring lasting change.

year: 2021-11-03

title: The role of intratidal oscillations in sediment resuspension in a diurnal, partially mixed estuary

authors: O’Callaghan, J.M.

subjects: diurnal tides

abstract: Using detailed observations of the mean and turbulent properties of flow, salinity and turbidity that spanned 2001/02, we examined the physical mechanisms underpinning sediment resuspension in the low-energy Swan River estuary, Western Australia. In this diurnal tidally-dominated estuary, the presence of intratidal oscillations, a tidal inequality lasting 2 to 3 hours on the flood tide, generated by interactions of the four main diurnal and semidiurnal astronomical constituents, K₁, O₁, M₂, and S₂, played a major role in modifying vertical stratification and mixing. These intratidal oscillations are controlled by phase differences between the tropic and synodic months rather than being temporally-fixed by bed friction, as occurs in semidiurnal estuaries. Intratidal oscillations are largest, at around 0.1 m, near to the Austral solstice when the lunar and solar declination are in-phase. Despite the seemingly small change in water level, shear-induced interfacial mixing caused destratification of the water column with the top-to-bottom salinity (ΔS) difference of 3.5 present early in the flood tide eroded to less than 0.3 by the end of the intratidal oscillation. High turbidity peaks, of 250 nephelometric turbidity units, coincided with these intratidal oscillations and could not be explained by bed friction since shear stress from mean flow did not exceed threshold criteria. High Reynolds stresses of ∼1 Nm⁻² did, however, exceed τcr and together with negative Reynolds fluxes indicate a net downward transport of material. Destratification of the water column induced by shear instabilities resulted in large overturns capable of moving in situ material towards the bed during intratidal oscillations and these turbidities were ∼10 times greater than those from bed-generated resuspension observed later during the flood tide.

text: The role of intratidal oscillations in sediment resuspension in a diurnal, partially mixed estuary Using detailed observations of the mean and turbulent properties of flow, salinity and turbidity that spanned 2001/02, we examined the physical mechanisms underpinning sediment resuspension in the low-energy Swan River estuary, Western Australia. In this diurnal tidally-dominated estuary, the presence of intratidal oscillations, a tidal inequality lasting 2 to 3 hours on the flood tide, generated by interactions of the four main diurnal and semidiurnal astronomical constituents, K₁, O₁, M₂, and S₂, played a major role in modifying vertical stratification and mixing. These intratidal oscillations are controlled by phase differences between the tropic and synodic months rather than being temporally-fixed by bed friction, as occurs in semidiurnal estuaries. Intratidal oscillations are largest, at around 0.1 m, near to the Austral solstice when the lunar and solar declination are in-phase. Despite the seemingly small change in water level, shear-induced interfacial mixing caused destratification of the water column with the top-to-bottom salinity (ΔS) difference of 3.5 present early in the flood tide eroded to less than 0.3 by the end of the intratidal oscillation. High turbidity peaks, of 250 nephelometric turbidity units, coincided with these intratidal oscillations and could not be explained by bed friction since shear stress from mean flow did not exceed threshold criteria. High Reynolds stresses of ∼1 Nm⁻² did, however, exceed τcr and together with negative Reynolds fluxes indicate a net downward transport of material. Destratification of the water column induced by shear instabilities resulted in large overturns capable of moving in situ material towards the bed during intratidal oscillations and these turbidities were ∼10 times greater than those from bed-generated resuspension observed later during the flood tide.

year: 2010

title: Secondary school subject choice: an ethnographic study

authors: Darnell, Doreen Anne

abstract: This study of subject choice followed two groups of pupils through the decision-making process at two state, co-educational high schools in the North Island of New Zealand. The high schools were similar in size, location, ethnic composition and range of home background of pupils, but had differing option systems. 
At the end of their form two year, 53 children (27 boys, 26 girls) were interviewed at their respective primary or intermediate schools while they were considering the options offered to them in form three at one of the two high schools. The children were re-interviewed the following year at their respective high schools. A further 37 pupils (17 boys, 20 girls) were interviewed in form four at their respective high schools while they were choosing fifth form subjects and were re-interviewed the following year after they had experienced the subjects they had chosen. All children in the study were chosen by their teachers as being representative of the range of pupils at their schools, in terms of ability, ethnic origin and home background. 
In addition, parents of eight of the younger children were interviewed in their homes and 31 teachers, representing all the subjects offered to the children at the two high schools, were interviewed at their respective schools. 
Analysis of interview transcripts showed that pupils’ decisions were influenced by the structure of the option systems, the attitudes of parents and peers and by the overt and covert actions of teachers. Access to information was found to be a key component of decision making. Children’s and parents’ views about the school subjects showed a strong measure of agreement, but there was less agreement between children’ views and teachers’ views. 
A model of decision making was elicited from the data and case studies illustrated the range of pupils’ individual experience, in particular, the experience of Maori pupils identified as ‘winners’ and ‘losers’ in the school system.

text: Secondary school subject choice: an ethnographic study This study of subject choice followed two groups of pupils through the decision-making process at two state, co-educational high schools in the North Island of New Zealand. The high schools were similar in size, location, ethnic composition and range of home background of pupils, but had differing option systems. 
At the end of their form two year, 53 children (27 boys, 26 girls) were interviewed at their respective primary or intermediate schools while they were considering the options offered to them in form three at one of the two high schools. The children were re-interviewed the following year at their respective high schools. A further 37 pupils (17 boys, 20 girls) were interviewed in form four at their respective high schools while they were choosing fifth form subjects and were re-interviewed the following year after they had experienced the subjects they had chosen. All children in the study were chosen by their teachers as being representative of the range of pupils at their schools, in terms of ability, ethnic origin and home background. 
In addition, parents of eight of the younger children were interviewed in their homes and 31 teachers, representing all the subjects offered to the children at the two high schools, were interviewed at their respective schools. 
Analysis of interview transcripts showed that pupils’ decisions were influenced by the structure of the option systems, the attitudes of parents and peers and by the overt and covert actions of teachers. Access to information was found to be a key component of decision making. Children’s and parents’ views about the school subjects showed a strong measure of agreement, but there was less agreement between children’ views and teachers’ views. 
A model of decision making was elicited from the data and case studies illustrated the range of pupils’ individual experience, in particular, the experience of Maori pupils identified as ‘winners’ and ‘losers’ in the school system.

year: 1985