title: Oxytocin receptor blockade reduces acquisition but not retrieval of taste aversion and blunts responsiveness of amygdala neurons to an aversive stimulus

authors: Olszewski, Pawel K.

subjects: anorexia

abstract: When gastrointestinal sickness induced by toxin injection is associated with exposure to novel food, the animal acquires a conditioned taste aversion (CTA). Malaise is accompanied by a surge in oxytocin release and in oxytocin neuronal activity; however, it is unclear whether oxytocin is a key facilitator of aversion or merely its marker. Herein we investigated whether blockade of the oxytocin receptor with the blood–brain barrier penetrant oxytocin receptor antagonist L-368,899 is detrimental for the acquisition and/or retrieval of lithium chloride (LiCl)-dependent CTA to a saccharin solution in mice. We also examined whether L-368,899 given prior to LiCl affects neuronal activity defined through c-Fos immunohistochemistry in select brain sites facilitating CTA acquisition. L-368,899 given prior to LiCl caused a 30% increase in saccharin solution intake in a two-bottle test, but when the antagonist was administered before the two-bottle test, it failed to diminish the retrieval of an existing CTA. LiCl administration increased c-Fos expression in the hypothalamic paraventricular and supraoptic nuclei, area postrema, nucleus of the solitary tract and basolateral and central (CNA) nuclei of the amygdala. L-368,899 injected before LiCl reduced the number of c-Fos positive CNA neurons and brought it down to levels similar to those observed in mice treated only with L-368,899. We conclude that oxytocin is one of the key components in acquisition of LiCl-induced CTA and the aversive response can be alleviated by the oxytocin receptor blockade. Oxytocin receptor antagonism blunts responsiveness of CNA to peripherally injected LiCl.

text: Oxytocin receptor blockade reduces acquisition but not retrieval of taste aversion and blunts responsiveness of amygdala neurons to an aversive stimulus When gastrointestinal sickness induced by toxin injection is associated with exposure to novel food, the animal acquires a conditioned taste aversion (CTA). Malaise is accompanied by a surge in oxytocin release and in oxytocin neuronal activity; however, it is unclear whether oxytocin is a key facilitator of aversion or merely its marker. Herein we investigated whether blockade of the oxytocin receptor with the blood–brain barrier penetrant oxytocin receptor antagonist L-368,899 is detrimental for the acquisition and/or retrieval of lithium chloride (LiCl)-dependent CTA to a saccharin solution in mice. We also examined whether L-368,899 given prior to LiCl affects neuronal activity defined through c-Fos immunohistochemistry in select brain sites facilitating CTA acquisition. L-368,899 given prior to LiCl caused a 30% increase in saccharin solution intake in a two-bottle test, but when the antagonist was administered before the two-bottle test, it failed to diminish the retrieval of an existing CTA. LiCl administration increased c-Fos expression in the hypothalamic paraventricular and supraoptic nuclei, area postrema, nucleus of the solitary tract and basolateral and central (CNA) nuclei of the amygdala. L-368,899 injected before LiCl reduced the number of c-Fos positive CNA neurons and brought it down to levels similar to those observed in mice treated only with L-368,899. We conclude that oxytocin is one of the key components in acquisition of LiCl-induced CTA and the aversive response can be alleviated by the oxytocin receptor blockade. Oxytocin receptor antagonism blunts responsiveness of CNA to peripherally injected LiCl.

year: 2013

title: Three essays on corporate default prediction : special reference to corporate governance, default correlation and capital structure dynamics

authors: Fernando, Ruwani

subjects: Default prediction

abstract: This thesis consists of three essays that investigate corporate defaults connected to corporate governance, default correlations and capital structure adjustment. Granting a loan requires mutual trust between lenders and borrower and depends on the flow of information. The relevance and the accuracy of the information are necessary to ensure the best judgement about the creditworthiness of borrowers. However, information asymmetry between the borrower and the lender is the main hurdle for any judgement about the borrower. Although default prediction has commanded the attention of researchers over many years, there is still an important gap in the literature on the selection of the suitable default predictor information for improved borrower evaluation. 
To broaden the understanding of the information content of default predictor variables, the first essay addresses and tests the impact of corporate governance on default prediction. It examines several testable hypotheses regarding the relations between corporate governance and default prediction, building on the Standard and Poor (2002) corporate governance framework proposed by Ashbaugh-Skaife et al. (2006). The research employs the conventional logistic regression to provide empirical evidence from U.S. default data over the period of 2000 to 2015. Empirical results are consistent with the following notions: First, default firms are associated with high ownership concentration, low shareholder rights, low financial transparency and disclosures, and less board effectiveness. 
Second, in-sample and out-of-sample tests support the incremental contribution of corporate governance information on default prediction, when compared with the models involving just financial information. 
In addition to the analyses on the U.S. data, this thesis conducts a comparative study using the data of Sri Lanka, which serves as a representative emerging market. This study argues that emerging markets are important because they present several institutional differences that cannot be examined in the developed markets. The rapid evolvement of these markets provides excellent experimental grounds for studying many financial issues. The empirical results show that whilst an integrated model provides overall stronger predictive value; financial information is more relevant for USA firms. Corporate governance appears more relevant in emerging markets than in mature markets, but the effectiveness of the individual corporate governance practices differs between countries. 
The second essay discusses the impact of corporate governance on the correlation in corporate defaults. This essay investigates for the first time the effect of firm-specific corporate governance on default correlation as an extension to the contagion and cyclical effect proposed by Das et al. (2007) as the sources of default correlation. It hypothesizes that the degree of default correlations could increase disproportionally for firms with weak corporate governance in terms of high ownership concentration, low board effectiveness, low financial transparency, and higher shareholder rights. This study employs Lucas’s (1995) method to provide empirical evidence based on the historical default data from the United States from 2000 to 2015. The empirical results imply that corporate governance is essential for credit risk management because poor corporate governance may increase not only individual default risk but also the domino effect of credit defaults. Moreover, the impact of corporate governance on the correlation in corporate defaults is more pronounced in the financial crisis.
The third essay examines the heterogeneity of the speed of capital structure adjustment in firms. In contrast to previously documented contemporaneous results, it tests the issue through distinguishing two types of the firms (default and non-default firms), and two measures of the speed of adjustment (cumulative versus marginal). The empirical results show that the speed of adjustment is non-uniform across firms and over time. In particular, default firms are associated with a higher speed of adjustment than non-default firms. The completion of leverage adjustment takes multiple periods. The marginal speed of adjustment accelerates from the beginning period to the end period, which is consistent with the anchoring and adjustment bias heuristic. The empirical results are robust using a book/market leverage and a two/one-step estimation approach. In addition to the tests on the speed of capital structure adjustment, this essay also examines the effect of leverage deviation on measuring firms’ default risk. The in-sample and out-of-sample tests suggest that taking into account leverage deviation enhances the capacity of measuring corporate borrowers’ default risk. Additionally, such benefit is persistent over various time horizons. Overall, the empirical findings provide important policy implications for banks before granting loans to corporate customers. This work fills crucial gaps in the credit risk literature.

text: Three essays on corporate default prediction : special reference to corporate governance, default correlation and capital structure dynamics This thesis consists of three essays that investigate corporate defaults connected to corporate governance, default correlations and capital structure adjustment. Granting a loan requires mutual trust between lenders and borrower and depends on the flow of information. The relevance and the accuracy of the information are necessary to ensure the best judgement about the creditworthiness of borrowers. However, information asymmetry between the borrower and the lender is the main hurdle for any judgement about the borrower. Although default prediction has commanded the attention of researchers over many years, there is still an important gap in the literature on the selection of the suitable default predictor information for improved borrower evaluation. 
To broaden the understanding of the information content of default predictor variables, the first essay addresses and tests the impact of corporate governance on default prediction. It examines several testable hypotheses regarding the relations between corporate governance and default prediction, building on the Standard and Poor (2002) corporate governance framework proposed by Ashbaugh-Skaife et al. (2006). The research employs the conventional logistic regression to provide empirical evidence from U.S. default data over the period of 2000 to 2015. Empirical results are consistent with the following notions: First, default firms are associated with high ownership concentration, low shareholder rights, low financial transparency and disclosures, and less board effectiveness. 
Second, in-sample and out-of-sample tests support the incremental contribution of corporate governance information on default prediction, when compared with the models involving just financial information. 
In addition to the analyses on the U.S. data, this thesis conducts a comparative study using the data of Sri Lanka, which serves as a representative emerging market. This study argues that emerging markets are important because they present several institutional differences that cannot be examined in the developed markets. The rapid evolvement of these markets provides excellent experimental grounds for studying many financial issues. The empirical results show that whilst an integrated model provides overall stronger predictive value; financial information is more relevant for USA firms. Corporate governance appears more relevant in emerging markets than in mature markets, but the effectiveness of the individual corporate governance practices differs between countries. 
The second essay discusses the impact of corporate governance on the correlation in corporate defaults. This essay investigates for the first time the effect of firm-specific corporate governance on default correlation as an extension to the contagion and cyclical effect proposed by Das et al. (2007) as the sources of default correlation. It hypothesizes that the degree of default correlations could increase disproportionally for firms with weak corporate governance in terms of high ownership concentration, low board effectiveness, low financial transparency, and higher shareholder rights. This study employs Lucas’s (1995) method to provide empirical evidence based on the historical default data from the United States from 2000 to 2015. The empirical results imply that corporate governance is essential for credit risk management because poor corporate governance may increase not only individual default risk but also the domino effect of credit defaults. Moreover, the impact of corporate governance on the correlation in corporate defaults is more pronounced in the financial crisis.
The third essay examines the heterogeneity of the speed of capital structure adjustment in firms. In contrast to previously documented contemporaneous results, it tests the issue through distinguishing two types of the firms (default and non-default firms), and two measures of the speed of adjustment (cumulative versus marginal). The empirical results show that the speed of adjustment is non-uniform across firms and over time. In particular, default firms are associated with a higher speed of adjustment than non-default firms. The completion of leverage adjustment takes multiple periods. The marginal speed of adjustment accelerates from the beginning period to the end period, which is consistent with the anchoring and adjustment bias heuristic. The empirical results are robust using a book/market leverage and a two/one-step estimation approach. In addition to the tests on the speed of capital structure adjustment, this essay also examines the effect of leverage deviation on measuring firms’ default risk. The in-sample and out-of-sample tests suggest that taking into account leverage deviation enhances the capacity of measuring corporate borrowers’ default risk. Additionally, such benefit is persistent over various time horizons. Overall, the empirical findings provide important policy implications for banks before granting loans to corporate customers. This work fills crucial gaps in the credit risk literature.

year: 2019

title: An exploration of the role of semantic relations in the theory and practice of translation (with special reference to English/Māori and Māori/English translation)

authors: Roa, Tom

subjects: clause relations

abstract: It is over forty years since Beekman and Callow, working within the context of the tagmemic tradition, drew attention to the potential significance so far as the theory and practice of translation are concerned of inter-propositional relations (also referred to as ‘discourse relations’, 'semantic relations', ‘semantico-pragmatic relations’, 'rhetorical relations’ and ‘clause relations’).  Since then, the importance of these relations has been increasingly acknowledged within linguistics and a range of other disciplines, including artificial intelligence. In spite of this, inter-propositional relations remain largely unexplored by the vast majority of those involved in translation. My aim in this research project was to determine (a) what impact, if any, a short training course in inter-propositional relations and inter-propositional relational signalling had on novice Māori-English/ English-Māori translators, and (b)  what impact my own understanding of these relations has had on my own practice as a translator. In connection with this, I conducted two studies.  

In the first of these studies, two small groups of novice translators were asked to translate seven text segments - some from English into te reo Māori, others from te reo Māori into English. They were then given a two-day workshop on inter-propositional relations and inter-propositional relational signalling in English and te reo Māori. No translation exercises were included in the workshop. The novice translators were then asked to translate the same text segments again. Comparison of the two sets of translations revealed some interesting differences, the second set indicating a higher level of sensitivity to inter-propositional relations and their signalling in the original text segments. This resulted in, it is argued here, translations that more accurately reflect authorial intentions as indicated in the source texts (see Chapter 3). In connection with this, it is relevant to note that, as indicated in the introductory chapter (Chapter 1) and in parts of the literature review (Chapter 2), while some of those involved in the Western tradition of translation theory and practice have argued that authorial intention is largely irrelevant in relation to textual interpretation, this essentially post-structural positioning is not available to those involved in translating indigenous texts within the context of indigenous worldviews.

In the second study, I used self-reflective think-aloud protocols to record my thoughts during the process of translating, from English into te reo Māori, text segments from five very different texts, all of these translations having been commissioned by different commissioning agencies. I then, making reference to the think-aloud transcripts, compared the source texts with the translations to determine the ways in which my reflections on inter-propositional relations and their signalling had impacted on the translations (Chapter 4).

My overall conclusion is that an understanding of inter-propositional relations and inter-propositional relational signalling can make a positive contribution to the theory and practice of translation and should be included in translator training and in the teaching of additional languages more generally (Chapter 5).

text: An exploration of the role of semantic relations in the theory and practice of translation (with special reference to English/Māori and Māori/English translation) It is over forty years since Beekman and Callow, working within the context of the tagmemic tradition, drew attention to the potential significance so far as the theory and practice of translation are concerned of inter-propositional relations (also referred to as ‘discourse relations’, 'semantic relations', ‘semantico-pragmatic relations’, 'rhetorical relations’ and ‘clause relations’).  Since then, the importance of these relations has been increasingly acknowledged within linguistics and a range of other disciplines, including artificial intelligence. In spite of this, inter-propositional relations remain largely unexplored by the vast majority of those involved in translation. My aim in this research project was to determine (a) what impact, if any, a short training course in inter-propositional relations and inter-propositional relational signalling had on novice Māori-English/ English-Māori translators, and (b)  what impact my own understanding of these relations has had on my own practice as a translator. In connection with this, I conducted two studies.  

In the first of these studies, two small groups of novice translators were asked to translate seven text segments - some from English into te reo Māori, others from te reo Māori into English. They were then given a two-day workshop on inter-propositional relations and inter-propositional relational signalling in English and te reo Māori. No translation exercises were included in the workshop. The novice translators were then asked to translate the same text segments again. Comparison of the two sets of translations revealed some interesting differences, the second set indicating a higher level of sensitivity to inter-propositional relations and their signalling in the original text segments. This resulted in, it is argued here, translations that more accurately reflect authorial intentions as indicated in the source texts (see Chapter 3). In connection with this, it is relevant to note that, as indicated in the introductory chapter (Chapter 1) and in parts of the literature review (Chapter 2), while some of those involved in the Western tradition of translation theory and practice have argued that authorial intention is largely irrelevant in relation to textual interpretation, this essentially post-structural positioning is not available to those involved in translating indigenous texts within the context of indigenous worldviews.

In the second study, I used self-reflective think-aloud protocols to record my thoughts during the process of translating, from English into te reo Māori, text segments from five very different texts, all of these translations having been commissioned by different commissioning agencies. I then, making reference to the think-aloud transcripts, compared the source texts with the translations to determine the ways in which my reflections on inter-propositional relations and their signalling had impacted on the translations (Chapter 4).

My overall conclusion is that an understanding of inter-propositional relations and inter-propositional relational signalling can make a positive contribution to the theory and practice of translation and should be included in translator training and in the teaching of additional languages more generally (Chapter 5).

year: 2016