title: Measurement of feeding motivation in sheep and the effects of food restriction

authors: Verbeek, Else

subjects: behavioural demand

abstract: The availability of food is a crucial factor determining the health and growth of animals. Prolonged or severe food restriction will trigger the subjective state of hunger, which could potentially reduce welfare. We refined a methodology for the measurement of feeding motivation as an indicator of hunger, evaluated the effects of food restriction on feeding motivation in ewes (Ovis aries) and applied a behavioural demand analysis to the data. Sixteen ewes were exposed to five different cost levels (i.e., 2, 6.6, 12.1, 22, or 40 m walking distances per reward) and two feeding levels (24 h restriction and an un-restricted control). We found that 24 h restricted ewes worked for a higher number of rewards (P < 0.001), walked a greater total distance (P < 0.001) and approached the feeding station faster on the first visit (P < 0.001). Therefore, the methodology was able to detect differences in feeding motivation between restricted and control ewes and is a potential indirect indicator of hunger. A generic demand function fitted to the data showed that the elasticity of demand, the maximum price paid (Pmax) and maximum expenditure (Omax) were not sensitive indicators of motivation, probably because we did not generate a complete demand curve. Imposing a cost by providing sheep with the opportunity to walk for their food could be a valuable tool in establishing acceptable feeding levels from an animals’ perspective. However, more research on validating behavioural demand measures as indicators of motivation is needed.

text: Measurement of feeding motivation in sheep and the effects of food restriction The availability of food is a crucial factor determining the health and growth of animals. Prolonged or severe food restriction will trigger the subjective state of hunger, which could potentially reduce welfare. We refined a methodology for the measurement of feeding motivation as an indicator of hunger, evaluated the effects of food restriction on feeding motivation in ewes (Ovis aries) and applied a behavioural demand analysis to the data. Sixteen ewes were exposed to five different cost levels (i.e., 2, 6.6, 12.1, 22, or 40 m walking distances per reward) and two feeding levels (24 h restriction and an un-restricted control). We found that 24 h restricted ewes worked for a higher number of rewards (P < 0.001), walked a greater total distance (P < 0.001) and approached the feeding station faster on the first visit (P < 0.001). Therefore, the methodology was able to detect differences in feeding motivation between restricted and control ewes and is a potential indirect indicator of hunger. A generic demand function fitted to the data showed that the elasticity of demand, the maximum price paid (Pmax) and maximum expenditure (Omax) were not sensitive indicators of motivation, probably because we did not generate a complete demand curve. Imposing a cost by providing sheep with the opportunity to walk for their food could be a valuable tool in establishing acceptable feeding levels from an animals’ perspective. However, more research on validating behavioural demand measures as indicators of motivation is needed.

year: 2011

title: Uptake of iron and its effect on grain refinement of pure magnesium by zirconium

authors: Cao, Peng

subjects: grain refinement

abstract: The uptake of iron by molten magnesium from uncoated new mild steel crucibles at temperatures 680°C, 730°C, and 780°C has been investigated. It was shown that the uptake of iron was sluggish at 680°C and the use of 0.05% zirconium addition could effectively suppress the increase in iron content within the first 2 h of holding at temperature. Rapid and severe uptake of iron was observed at 780°C. As a consequence, it was found that the grain refinement of pure magnesium achieved by 1% zirconium addition nearly vanished after 60 min hold at 780°C due to the depletion of soluble zirconium. The uptake of iron at 730°C was conspicuous but it was still controllable by use of 0.05% zirconium addition within the first 60 min of holding at temperature. The work conducted using an aluminium titanite crucible and a boron nitride coated mild steel crucible at 730°C further confirmed the highly detrimental influence of the uptake of iron on the grain refinement of pure magnesium by zirconium. The characteristic zirconium rich coring structures developed from circular to rosette like when the melt was held at 730°C in an uncoated mild steel crucible, while no such evolution was observed when held in an aluminium titanite crucible at the same temperature. Recommendations to minimise the consumption of zirconium by the uptake of iron were made based on the results obtained from this investigation. The mechanism of grain refinement of magnesium by a low concentration of zirconium is discussed.

text: Uptake of iron and its effect on grain refinement of pure magnesium by zirconium The uptake of iron by molten magnesium from uncoated new mild steel crucibles at temperatures 680°C, 730°C, and 780°C has been investigated. It was shown that the uptake of iron was sluggish at 680°C and the use of 0.05% zirconium addition could effectively suppress the increase in iron content within the first 2 h of holding at temperature. Rapid and severe uptake of iron was observed at 780°C. As a consequence, it was found that the grain refinement of pure magnesium achieved by 1% zirconium addition nearly vanished after 60 min hold at 780°C due to the depletion of soluble zirconium. The uptake of iron at 730°C was conspicuous but it was still controllable by use of 0.05% zirconium addition within the first 60 min of holding at temperature. The work conducted using an aluminium titanite crucible and a boron nitride coated mild steel crucible at 730°C further confirmed the highly detrimental influence of the uptake of iron on the grain refinement of pure magnesium by zirconium. The characteristic zirconium rich coring structures developed from circular to rosette like when the melt was held at 730°C in an uncoated mild steel crucible, while no such evolution was observed when held in an aluminium titanite crucible at the same temperature. Recommendations to minimise the consumption of zirconium by the uptake of iron were made based on the results obtained from this investigation. The mechanism of grain refinement of magnesium by a low concentration of zirconium is discussed.

year: 2004-05

title: Ko au te whenua, te whenua ko au  – I am the land, the land is me: An autoethnographic investigation of a secondary school teacher’s experience seeking to enrich learning in outdoor  education for Māori students.

authors: Townsend, Jane Emma

subjects: place-responsive

abstract: This thesis is my story as an outdoor educator, as a researcher, and a co-participant reflecting on my own actions and experiences as well as those of my students. In this autoethnography I share my revelations and tensions in my role as an outdoor education teacher seeking to enrich the experiences of Māori students.  Māori culture and history have largely been ignored in the outdoor education classrooms and environments of Aotearoa New Zealand. After teaching the subject for ten years I didn’t perceive that I was perpetuating the same invisibility in my own outdoor education course. Over this time a number of questions that had fermented at the back of my mind came to the fore; ‘why are so few Māori students opting to take outdoor education as a senior secondary school subject?’ and ‘how can I make the subject of outdoor education more desirable and appealing to Māori?’ A place-responsive approach incorporates and values traditional ways of learning through the notion of place and the stories attached to them. The cultural context of learning about and through place has the potential to provide learning opportunities that are relevant and meaningful to all learners but particularly Māori. Place-responsive pedagogies allow outdoor educators to create an environment where language, knowledge, culture and values are normal, valid and legitimate – contexts where Māori students can be themselves. Through this research I have found that the implementation of a place responsive approach has had significant implications for Year twelve outdoor education at Mount Maunganui College. The improvement in Māori student achievement and numbers selecting the subject have  been affirming.

Ko au te whenua, te whenua ko au – I am the land, the land is me

text: Ko au te whenua, te whenua ko au  – I am the land, the land is me: An autoethnographic investigation of a secondary school teacher’s experience seeking to enrich learning in outdoor  education for Māori students. This thesis is my story as an outdoor educator, as a researcher, and a co-participant reflecting on my own actions and experiences as well as those of my students. In this autoethnography I share my revelations and tensions in my role as an outdoor education teacher seeking to enrich the experiences of Māori students.  Māori culture and history have largely been ignored in the outdoor education classrooms and environments of Aotearoa New Zealand. After teaching the subject for ten years I didn’t perceive that I was perpetuating the same invisibility in my own outdoor education course. Over this time a number of questions that had fermented at the back of my mind came to the fore; ‘why are so few Māori students opting to take outdoor education as a senior secondary school subject?’ and ‘how can I make the subject of outdoor education more desirable and appealing to Māori?’ A place-responsive approach incorporates and values traditional ways of learning through the notion of place and the stories attached to them. The cultural context of learning about and through place has the potential to provide learning opportunities that are relevant and meaningful to all learners but particularly Māori. Place-responsive pedagogies allow outdoor educators to create an environment where language, knowledge, culture and values are normal, valid and legitimate – contexts where Māori students can be themselves. Through this research I have found that the implementation of a place responsive approach has had significant implications for Year twelve outdoor education at Mount Maunganui College. The improvement in Māori student achievement and numbers selecting the subject have  been affirming.

Ko au te whenua, te whenua ko au – I am the land, the land is me

year: 2014