title: Distribution of tetrodotoxin in the New Zealand clam, Paphies australis, established using immunohistochemistry and liquid chromatography-tandem quadrupole mass spectrometry

authors: Biessy, Laura

subjects: biotoxin

abstract: Tetrodotoxin (TTX) is one of the most potent neurotoxins known. It was originally thought to only occur in puffer fish but has now been identified in twelve different classes of freshwater and marine organisms, including bivalves. Despite being one of the world’s most studied biotoxins, its origin remains uncertain. There is contradictory evidence regarding the source of TTX and its pathway through food webs. To date, the distribution of TTX has not been examined in bivalves. In the present study, 48 Paphies australis, a TTX-containing clam species endemic to New Zealand, were collected. Thirty clams were dissected, and organs and tissues pooled into five categories (siphons, digestive gland, adductor muscles, and the ‘rest’) and analyzed for TTX using liquid chromatography-mass spectrometry (LC-MS). The micro-distribution of TTX was visualized in the remaining 18 individuals using an immunohistological technique incorporating a TTX-specific monoclonal antibody. The LC-MS analysis revealed that siphons contained the highest concentrations of TTX (mean 403.8 µg/kg). Immunohistochemistry analysis showed TTX in the outer cells of the siphons, but also in the digestive system, foot, and gill tissue. Observing TTX in organs involved in feeding provides initial evidence to support the hypothesis of an exogenous source in P. australis.

text: Distribution of tetrodotoxin in the New Zealand clam, Paphies australis, established using immunohistochemistry and liquid chromatography-tandem quadrupole mass spectrometry Tetrodotoxin (TTX) is one of the most potent neurotoxins known. It was originally thought to only occur in puffer fish but has now been identified in twelve different classes of freshwater and marine organisms, including bivalves. Despite being one of the world’s most studied biotoxins, its origin remains uncertain. There is contradictory evidence regarding the source of TTX and its pathway through food webs. To date, the distribution of TTX has not been examined in bivalves. In the present study, 48 Paphies australis, a TTX-containing clam species endemic to New Zealand, were collected. Thirty clams were dissected, and organs and tissues pooled into five categories (siphons, digestive gland, adductor muscles, and the ‘rest’) and analyzed for TTX using liquid chromatography-mass spectrometry (LC-MS). The micro-distribution of TTX was visualized in the remaining 18 individuals using an immunohistological technique incorporating a TTX-specific monoclonal antibody. The LC-MS analysis revealed that siphons contained the highest concentrations of TTX (mean 403.8 µg/kg). Immunohistochemistry analysis showed TTX in the outer cells of the siphons, but also in the digestive system, foot, and gill tissue. Observing TTX in organs involved in feeding provides initial evidence to support the hypothesis of an exogenous source in P. australis.

year: 2018

title: Studying and exploiting the relationship between model accuracy and explanation quality

authors: Jia, Yunzhe

subjects: computer science

abstract: Many explanation methods have been proposed to reveal insights about the internal procedures of black-box models like deep neural networks. Although these methods are able to generate explanations for individual predictions, little research has been conducted to investigate the relationship of model accuracy and explanation quality, or how to use explanations to improve model performance. In this paper, we evaluate explanations using a metric based on area under the ROC curve (AUC), treating expert-provided image annotations as ground-truth explanations, and quantify the correlation between model accuracy and explanation quality when performing image classifications with deep neural networks. The experiments are conducted using two image datasets: the CUB-200-2011 dataset and a Kahikatea dataset that we publish with this paper. For each dataset, we compare and evaluate seven different neural networks with four different explainers in terms of both accuracy and explanation quality. We also investigate how explanation quality evolves as loss metrics change through the training iterations of each model. The experiments suggest a strong correlation between model accuracy and explanation quality. Based on this observation, we demonstrate how explanations can be exploited to benefit the model selection process—even if simply maximising accuracy on test data is the primary goal.

text: Studying and exploiting the relationship between model accuracy and explanation quality Many explanation methods have been proposed to reveal insights about the internal procedures of black-box models like deep neural networks. Although these methods are able to generate explanations for individual predictions, little research has been conducted to investigate the relationship of model accuracy and explanation quality, or how to use explanations to improve model performance. In this paper, we evaluate explanations using a metric based on area under the ROC curve (AUC), treating expert-provided image annotations as ground-truth explanations, and quantify the correlation between model accuracy and explanation quality when performing image classifications with deep neural networks. The experiments are conducted using two image datasets: the CUB-200-2011 dataset and a Kahikatea dataset that we publish with this paper. For each dataset, we compare and evaluate seven different neural networks with four different explainers in terms of both accuracy and explanation quality. We also investigate how explanation quality evolves as loss metrics change through the training iterations of each model. The experiments suggest a strong correlation between model accuracy and explanation quality. Based on this observation, we demonstrate how explanations can be exploited to benefit the model selection process—even if simply maximising accuracy on test data is the primary goal.

year: 2021

title: Sovereignty and nation-building: The development challenge in Indian country today

authors: Crombie, Winifred

subjects: Native American economic development

abstract: In Sovereignty and Nation-Building: The Development Challenge in Indian Country Today, Cornell and Kalt (1998) argue that economic success, and the reduction of unemployment and welfare dependency, is more likely in the case of American Indian tribes if governance is characterised by five principles. In a number of articles and talks on Maori nation building projects in Aotearoa/New Zealand, reference has recently been made to Cornell and Kalt and to one or more of these five principles. Thus, for example, Dodd, in an article published in the Journal of Maori and Pacific Development in 2000, argues that Iwi governance structures should involve a separation of governance and management and should be consistent with indigenous ideas about the location and exercise of authority (2000, p.7). She refers, in this context, to the work of Cornell and Kalt, and quotes Eade who observes that “it is doubtful that an organisation that itself maintains oppressive social structures can be a reliable vehicle for transforming these in a liberating way, whatever the rhetoric” (Eade 1997, p. 26). More recently in this Journal, Tiakiwai and Bishop (2002, p. 36), note that Cornell and Kalt (1998, p.2) found a “positive correlation between self-determination and successful development as defined by the tribe”, and observe that what they refer to as the ‘decade of Maori development’ provides concrete Maori examples of development theorizing in line with Eade (1997) and the assertions of Cornell and Kalt (1998). The article by Cornell and Kalt which appears to be most often quoted in the context of Maori nation building projects first appeared in 1998. The extent of its current influence in Aotearoa/New Zealand suggests that a careful re-examination of it at this point could prove useful.

text: Sovereignty and nation-building: The development challenge in Indian country today In Sovereignty and Nation-Building: The Development Challenge in Indian Country Today, Cornell and Kalt (1998) argue that economic success, and the reduction of unemployment and welfare dependency, is more likely in the case of American Indian tribes if governance is characterised by five principles. In a number of articles and talks on Maori nation building projects in Aotearoa/New Zealand, reference has recently been made to Cornell and Kalt and to one or more of these five principles. Thus, for example, Dodd, in an article published in the Journal of Maori and Pacific Development in 2000, argues that Iwi governance structures should involve a separation of governance and management and should be consistent with indigenous ideas about the location and exercise of authority (2000, p.7). She refers, in this context, to the work of Cornell and Kalt, and quotes Eade who observes that “it is doubtful that an organisation that itself maintains oppressive social structures can be a reliable vehicle for transforming these in a liberating way, whatever the rhetoric” (Eade 1997, p. 26). More recently in this Journal, Tiakiwai and Bishop (2002, p. 36), note that Cornell and Kalt (1998, p.2) found a “positive correlation between self-determination and successful development as defined by the tribe”, and observe that what they refer to as the ‘decade of Maori development’ provides concrete Maori examples of development theorizing in line with Eade (1997) and the assertions of Cornell and Kalt (1998). The article by Cornell and Kalt which appears to be most often quoted in the context of Maori nation building projects first appeared in 1998. The extent of its current influence in Aotearoa/New Zealand suggests that a careful re-examination of it at this point could prove useful.

year: 2003-02