title: Groups with fix-set quasi-order

authors: Stokes, Tim E.

abstract: If X is a set, the fix-set quasiorder on a group of permutations of X is the quasiorder induced by containment of the fix-sets of elements of SX. Axioms for such quasiorders on groups have previously been given. We generalise these to allow non-faithful group actions, the resulting abstract quasiorders being called fix-orders. We characterise the possible fix-orders on a given group G in terms of certain families of subgroups of G. The special case in which the members of the defining family of subgroups are all normal is considered. Software is used to construct and analyse the lattices of fix-orders of many small finite groups.

text: Groups with fix-set quasi-order If X is a set, the fix-set quasiorder on a group of permutations of X is the quasiorder induced by containment of the fix-sets of elements of SX. Axioms for such quasiorders on groups have previously been given. We generalise these to allow non-faithful group actions, the resulting abstract quasiorders being called fix-orders. We characterise the possible fix-orders on a given group G in terms of certain families of subgroups of G. The special case in which the members of the defining family of subgroups are all normal is considered. Software is used to construct and analyse the lattices of fix-orders of many small finite groups.

year: 2015

title: Effect of oxytocin on hunger discrimination

authors: Head, Mitchell Antony

subjects: Science & Technology

abstract: Centrally and peripherally administered oxytocin (OT) decreases food intake and activation of the endogenous OT systems, which is associated with termination of feeding. Evidence gathered thus far points to OT as a facilitator of early satiation, a peptide that reduces the need for a meal that has already begun. It is not known, however, whether OT can diminish a feeling of hunger, thereby decreasing a perceived need to seek calories. Therefore, in the current project, we first confirmed that intraperitoneal (i.p.) OT at 0.3–1 mg/kg reduces food intake in deprived and non-deprived rats. We then used those OT doses in a unique hunger discrimination protocol. First, rats were trained to discriminate between 22- and 2-h food deprivation (hungry vs. sated state) in a two-lever operant procedure. After rats acquired the discrimination, they were food-restricted for 22 h and given i.p. OT before a generalization test session. OT did not decrease 22-h deprivation-appropriate responding to match that following 2-h food deprivation, thus, it did not reduce the perceived level of hunger. In order to better understand the mechanisms behind this ineffectiveness of OT, we used c-Fos immunohistochemistry to determine whether i.p. OT activates a different subset of feeding-related brain sites under 22- vs. 2-h deprivation. We found that in sated animals, OT induces c-Fos changes in a broader network of hypothalamic and brain stem sites compared to those affected in the hungry state. Finally, by employing qPCR analysis, we asked whether food deprivation vs. sated state have an impact on OT receptor expression in the brain stem, a CNS “entry” region for peripheral OT. Fasted animals had significantly lower OT receptor mRNA levels than their ad libitum-fed counterparts. We conclude that OT does not diminish a feeling of hunger before a start of a meal. Instead OT's anorexigenic properties are manifested once consumption has already begun which is—at least to some extent—driven by changes in brain responsiveness to OT treatment in the hungry vs. fed state. OT should be viewed as a mediator of early satiation rather than as a molecule that diminishes perceived hunger.

text: Effect of oxytocin on hunger discrimination Centrally and peripherally administered oxytocin (OT) decreases food intake and activation of the endogenous OT systems, which is associated with termination of feeding. Evidence gathered thus far points to OT as a facilitator of early satiation, a peptide that reduces the need for a meal that has already begun. It is not known, however, whether OT can diminish a feeling of hunger, thereby decreasing a perceived need to seek calories. Therefore, in the current project, we first confirmed that intraperitoneal (i.p.) OT at 0.3–1 mg/kg reduces food intake in deprived and non-deprived rats. We then used those OT doses in a unique hunger discrimination protocol. First, rats were trained to discriminate between 22- and 2-h food deprivation (hungry vs. sated state) in a two-lever operant procedure. After rats acquired the discrimination, they were food-restricted for 22 h and given i.p. OT before a generalization test session. OT did not decrease 22-h deprivation-appropriate responding to match that following 2-h food deprivation, thus, it did not reduce the perceived level of hunger. In order to better understand the mechanisms behind this ineffectiveness of OT, we used c-Fos immunohistochemistry to determine whether i.p. OT activates a different subset of feeding-related brain sites under 22- vs. 2-h deprivation. We found that in sated animals, OT induces c-Fos changes in a broader network of hypothalamic and brain stem sites compared to those affected in the hungry state. Finally, by employing qPCR analysis, we asked whether food deprivation vs. sated state have an impact on OT receptor expression in the brain stem, a CNS “entry” region for peripheral OT. Fasted animals had significantly lower OT receptor mRNA levels than their ad libitum-fed counterparts. We conclude that OT does not diminish a feeling of hunger before a start of a meal. Instead OT's anorexigenic properties are manifested once consumption has already begun which is—at least to some extent—driven by changes in brain responsiveness to OT treatment in the hungry vs. fed state. OT should be viewed as a mediator of early satiation rather than as a molecule that diminishes perceived hunger.

year: 2019

title: Have you heard of Hinehau? A research journey of reclamation

authors: Wakefield, Sandy

subjects: Te Tai Tokerau

abstract: As the Māori political and cultural movement continues to grow, issues of representation, power, and control are critiqued by Māori minds.
After discovering a tribal myth about the mana of a woman known as Hinehau, a chain reaction of enquiry develops into the reclamation of tribal knowledge.
By investigating the historical context surrounding the narrative of Hinehau, her story transcends the fairy-tale myth she was confined to, and exposes the rendering down of her story.
Under the umbrella of Western science, European and Pākehā historical archives created an enduring legacy of “Māori myth” that is synonymous with falsehood. Through the assertation of tribal oral tradition and connecting our experiences to our missing histories, Hinehau is relocated. The Hinehau story renews through reconnecting to mātauranga Māori, Ngāpuhi kōrero tuku iho and the creativity of the researcher. In this process, her story renews.
With the guidance of hapū members, mentors, and a diversity of literature, the narrative of Hinehau becomes a part of a much larger inter-tribal narrative held within an ancestral landscape which is sometimes hard to recognise in whenua we no longer have tribal autonomy over. Our Indigenous identity is still under threat as we are still “othered” in our tribal lands. This work contributes to pushing the envelope of what it means to think, exist, and challenge as tangata whenua in Aotearoa, where traditional tribal roles have been minimalised in society, or disappeared through generations of the colonial project (Tuhiwai Smith, 2012).

text: Have you heard of Hinehau? A research journey of reclamation As the Māori political and cultural movement continues to grow, issues of representation, power, and control are critiqued by Māori minds.
After discovering a tribal myth about the mana of a woman known as Hinehau, a chain reaction of enquiry develops into the reclamation of tribal knowledge.
By investigating the historical context surrounding the narrative of Hinehau, her story transcends the fairy-tale myth she was confined to, and exposes the rendering down of her story.
Under the umbrella of Western science, European and Pākehā historical archives created an enduring legacy of “Māori myth” that is synonymous with falsehood. Through the assertation of tribal oral tradition and connecting our experiences to our missing histories, Hinehau is relocated. The Hinehau story renews through reconnecting to mātauranga Māori, Ngāpuhi kōrero tuku iho and the creativity of the researcher. In this process, her story renews.
With the guidance of hapū members, mentors, and a diversity of literature, the narrative of Hinehau becomes a part of a much larger inter-tribal narrative held within an ancestral landscape which is sometimes hard to recognise in whenua we no longer have tribal autonomy over. Our Indigenous identity is still under threat as we are still “othered” in our tribal lands. This work contributes to pushing the envelope of what it means to think, exist, and challenge as tangata whenua in Aotearoa, where traditional tribal roles have been minimalised in society, or disappeared through generations of the colonial project (Tuhiwai Smith, 2012).

year: 2021