title: Connexin 36 as a Regulator of Consummatory Behaviour

authors: Christian, David

subjects: reward

abstract: Gap junctions enable metabolic and electrical coupling of adjacent cells. Connexin 36 (Cx36) is a gap junction protein found predominantly in mammalian neurons. Because Cx36 is expressed in many areas involved in the regulation of food intake, its role in this was explored. I therefore investigated whether genetic knockout (KO) of Cx36 affects the intake of various sweet tastants during long-term concurrent feeding with bland chow, and affects intake of sweet tastants alone during short-term feeding. In addition, I investigated whether a conditioned taste aversion (CTA) would be altered by KO of Cx36. LiCl was injected intraperitoneally (IP) following exposure to a sweet novel tastant. 48 hours later mice were given a two-bottle preference test of tastant vs. water to determine aversive response. Cx36 KO animals consumed less sweet palatable tastants and consumed more bland chow during long-term intake. Sweet tastant consumption was similarly increased during short-term intake. This is suggestive of Cx36 being implicated in both reward mediated and homeostatic regulation. A CTA was enhanced by the KO of Cx36, potentially due to its role in the reward system, and/or an effect of hypothalamic endocrine nuclei implicated in the acquisition of a CTA. In summary, Cx36 may be involved in reward system response to sweet palatable food consumption, and the magnitude of aversive response. Cx36 may also be implicated in post-ingestive endocrine food intake and aversion regulation.

text: Connexin 36 as a Regulator of Consummatory Behaviour Gap junctions enable metabolic and electrical coupling of adjacent cells. Connexin 36 (Cx36) is a gap junction protein found predominantly in mammalian neurons. Because Cx36 is expressed in many areas involved in the regulation of food intake, its role in this was explored. I therefore investigated whether genetic knockout (KO) of Cx36 affects the intake of various sweet tastants during long-term concurrent feeding with bland chow, and affects intake of sweet tastants alone during short-term feeding. In addition, I investigated whether a conditioned taste aversion (CTA) would be altered by KO of Cx36. LiCl was injected intraperitoneally (IP) following exposure to a sweet novel tastant. 48 hours later mice were given a two-bottle preference test of tastant vs. water to determine aversive response. Cx36 KO animals consumed less sweet palatable tastants and consumed more bland chow during long-term intake. Sweet tastant consumption was similarly increased during short-term intake. This is suggestive of Cx36 being implicated in both reward mediated and homeostatic regulation. A CTA was enhanced by the KO of Cx36, potentially due to its role in the reward system, and/or an effect of hypothalamic endocrine nuclei implicated in the acquisition of a CTA. In summary, Cx36 may be involved in reward system response to sweet palatable food consumption, and the magnitude of aversive response. Cx36 may also be implicated in post-ingestive endocrine food intake and aversion regulation.

year: 2014

title: On calibration of nested dichotomies

authors: Leathart, Tim

subjects: computer science

abstract: Nested dichotomies (NDs) are used as a method of transforming a multiclass classification problem into a series of binary problems. A tree structure is induced that recursively splits the set of classes into subsets, and a binary classification model learns to discriminate between the two subsets of classes at each node. In this paper, we demonstrate that these NDs typically exhibit poor probability calibration, even when the binary base models are well-calibrated. We also show that this problem is exacerbated when the binary models are poorly calibrated. We discuss the effectiveness of different calibration strategies and show that accuracy and log-loss can be significantly improved by calibrating both the internal base models and the full ND structure, especially when the number of classes is high.

text: On calibration of nested dichotomies Nested dichotomies (NDs) are used as a method of transforming a multiclass classification problem into a series of binary problems. A tree structure is induced that recursively splits the set of classes into subsets, and a binary classification model learns to discriminate between the two subsets of classes at each node. In this paper, we demonstrate that these NDs typically exhibit poor probability calibration, even when the binary base models are well-calibrated. We also show that this problem is exacerbated when the binary models are poorly calibrated. We discuss the effectiveness of different calibration strategies and show that accuracy and log-loss can be significantly improved by calibrating both the internal base models and the full ND structure, especially when the number of classes is high.

year: 2019

title: Ōpōtiki Mai Tawhiti Kapa Haka

authors: Maxwell, Te Kahautu

abstract: Ōpōtiki Mai Tawhiti competed in Te Matatini World Championship Kapa Haka Competition and placed second overall out of 45 kapa haka. Placed 1st Male Leader, 1st Waiata a Ringa Composition, 1st, Poi Composition, 2nd Haka Composition, 1st overall composition, 1st Waiata Tira, 1st Waiata a Ringa, 3rd Whakakeke, 2nd Poi.

text: Ōpōtiki Mai Tawhiti Kapa Haka Ōpōtiki Mai Tawhiti competed in Te Matatini World Championship Kapa Haka Competition and placed second overall out of 45 kapa haka. Placed 1st Male Leader, 1st Waiata a Ringa Composition, 1st, Poi Composition, 2nd Haka Composition, 1st overall composition, 1st Waiata Tira, 1st Waiata a Ringa, 3rd Whakakeke, 2nd Poi.

year: 2015