Treebank-based acquisition of LFG resources for Chinese

This paper presents a method to automatically acquire wide-coverage, robust, probabilistic Lexical-Functional Grammar resources for Chinese from the Penn Chinese Treebank (CTB). Our starting point is the earlier, proofof- concept work of (Burke et al., 2004) on automatic f-structure annotation, LFG grammar acquisition and parsing for Chinese using the CTB version 2 (CTB2). We substantially extend and improve on this earlier research as regards coverage, robustness, quality and fine-grainedness of the resulting LFG resources. We achieve this through (i) improved LFG analyses for a number of core Chinese phenomena; (ii) a new automatic f-structure annotation architecture which involves an intermediate dependency representation; (iii) scaling the approach from 4.1K trees in CTB2 to 18.8K trees in CTB version 5.1 (CTB5.1) and (iv) developing a novel treebank-based approach to recovering non-local dependencies (NLDs) for Chinese parser output. Against a new 200-sentence good standard of manually constructed f-structures, the method achieves 96.00% f-score for f-structures automatically generated for the original CTB trees and 80.01%for NLD-recovered f-structures generated for the trees output by Bikel’s parser

Recovering non-local dependencies for Chinese

To date, work on Non-Local Dependencies (NLDs) has focused almost exclusively on English and it is an open research question how well these approaches migrate to other languages. This paper surveys non-local dependency constructions in Chinese as represented in the Penn Chinese Treebank (CTB) and provides an approach for generating proper predicate-argument-modifier structures including NLDs from surface contextfree phrase structure trees. Our approach recovers non-local dependencies at the level of Lexical-Functional Grammar f-structures, using automatically acquired subcategorisation frames and f-structure paths linking antecedents and traces in NLDs. Currently our algorithm achieves 92.2% f-score for trace insertion and 84.3% for antecedent recovery evaluating on gold-standard CTB trees, and 64.7% and 54.7%, respectively, on CTBtrained state-of-the-art parser output trees

Monetary policy, investor sentiment and stock returns

This doctoral thesis empirically investigates the response of the U.S. market-wide and cross- sectional stock returns to monetary policy shocks after the Federal Open Market Committee (FOMC) meetings, across different sentiment states between June-89 to October-14. It also examines the impact of investor sentiment states on the market-wide stock price drift before the scheduled FOMC announcements. Chapter 1 demonstrates that the state of investor sentiment strongly affects the transmission of conventional and non-conventional monetary policy to the stock market. In particular, monetary policy shocks significantly affect market-wide stock returns only during sentiment- correction periods. In contrast, during periods of optimism build-up, the stock market response is statistically insignificant. The sentiment-based state dependence in the response of stock market returns to monetary policy shocks sheds important light on a sentiment channel in the monetary policy transmission mechanism. We extend our empirical analysis to cross-sectional stock returns in Chapter 2. Our estimates show that monetary policy shocks significantly affect cross-sectional stock returns only during sentiment-correction periods. We construct a long-short strategy, according to which we define the stocks which are more exposed to investor sentiment as the short leg. Our results show that monetary policy shocks positively drive the long-short spread, with a larger impact on the short leg stocks. Specially, Federal Funds Rate (FFR) surprises have larger impacts on the stocks with high accruals, young stocks, stocks with high asset growth rate, stocks with low book-to-market ratio, stocks with high cash to asset ratio, stocks with low gross profitability, high investment stocks, past loser stocks, stocks with high net operating assets, stocks with low asset tangibility, less profitable stocks, stocks with high return volatility, and large stocks before the zero lower bound (ZLB) was reached. The long-short strategy is reconstructed after the ZLB was reached due to changes in stocks’ sensitivity to investor sentiment. However, it is still the short leg stocks that are more affected by the path surprises. The stronger response of the short leg implies that the stocks which are more exposed to investor sentiment are also more sensitive to monetary policy shocks. Finally in Chapter 3 we examine how investor sentiment states affect the stock price drift before the scheduled FOMC announcements. We find that the returns on the S&P500 index increase significantly over the pre-FOMC window only during periods of high sentiment. We also find that investors allocate assets from low risk short-term T-bills to stocks on the pre- FOMC window during periods of high sentiment. Our findings on the pre-FOMC announcement order imbalance show that there are more buyer-initiated trade than seller-initiated trade on the S&P500 constituents during periods of high sentiment. These findings provide a behavioural explanation to the pre-FOMC announcement puzzle

Live and let die: asymmetric dimethylarginine and septic shock

Nitric oxide (NO) is an important mediator of host defence and of vascular tone. In septic shock, upregulation of inducible NO synthase leads to the production of vast amounts of NO, which contribute to pathogen elimination but also to inappropriate vasodilation and to loss of vascular resistance. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthases shown to contribute to the regulation of vascular tone. ADMA was recently identified as a marker of organ dysfunction and mortality in intensive care patients and as a novel cardiovascular risk factor. In the present issue of Critical Care, a study by O'Dwyer and colleagues identifies ADMA as a potential regulator of NO production in septic shock. Being an inhibitor of NO production, ADMA may at least partly counteract pathological hypotension, but at the same time may impair the NO-dependent host defence. A mechanism is proposed by which the interplay between ADMA and inducible NO synthase activity is mediated. ADMA levels should be determined in future studies evaluating the regulation of NO in the intensive care setting

Concise and Efficient Total Syntheses of Virenamides A and D

Concise total syntheses of linear thiazole-containing peptides virenamides A (1) and D (4), isolated from Australian ascidian Diplosoma virens have been accomplished from Boc-L-valine (6) in 7 steps. A cyclization between thioamide and bromoacetaldehyde was applied to form thiazole ring as a key step