The Effects of Economic News on Bond Market Liquidity

The authors contrast the impact of two sources of information flow on the volatility of prices, trading activity, and liquidity in the brokered interdealer market for Government of Canada bonds. Liquidity varies with the amount of asymmetric information in the market, and order flow plays a central role in the processing of information. The authors find a two-stage adjustment process in the period before and after a scheduled 8:30 a.m. macroeconomic news announcement that is similar to the adjustment process documented by Fleming and Remolona (1999) for the U.S. Treasury market. They contrast these dynamics with the adjustment that occurs around a Government of Canada bond auction. Results are somewhat inconsistent with the patterns observed around macroeconomic news events, but are explained by theory.Financial markets; Market structure and pricing; Debt management

An Empirical Analysis of Liquidity and Order Flow in the Brokered Interdealer Market for Government of Canada Bonds

The authors empirically measure Canadian bond market liquidity using a number of indicators proposed in the literature and detail, for the first time, price and trade dynamics in the Government of Canada secondary bond market. They find, consistent with Inoue (1999), that the Canadian brokered interdealer fixed-income market is relatively liquid for its size. Liquidity measures are analyzed relative to each other and across securities, and intraday patterns are identified. The authors' results show that trading activity is positively correlated with price volatility, and that signed order flow is significant in explaining contemporaneous high-frequency price movements. They find evidence that trading activity is positively related to liquidity measures in some markets, which suggests that indicators such as trade frequency and trading volume, despite certain drawbacks, can be seen as useful proxies for liquidity. The authors also document Canadian participants' prevalent use of an order expansion protocol, whereby order size can be negotiated upward once a trade has been initiated; although Boni and Leach (2002) identify this practice as consistent with a market where there is relatively strong concern regarding information asymmetry, the authors observe no consistent link between the frequency of its use and observations of trading activity, market liquidity, or price volatility.Financial markets; Market structure and pricing

Coupled catastrophes: sudden shifts cascade and hop among interdependent systems

An important challenge in several disciplines is to understand how sudden changes can propagate among coupled systems. Examples include the synchronization of business cycles, population collapse in patchy ecosystems, markets shifting to a new technology platform, collapses in prices and in confidence in financial markets, and protests erupting in multiple countries. A number of mathematical models of these phenomena have multiple equilibria separated by saddle-node bifurcations. We study this behavior in its normal form as fast--slow ordinary differential equations. In our model, a system consists of multiple subsystems, such as countries in the global economy or patches of an ecosystem. Each subsystem is described by a scalar quantity, such as economic output or population, that undergoes sudden changes via saddle-node bifurcations. The subsystems are coupled via their scalar quantity (e.g., trade couples economic output; diffusion couples populations); that coupling moves the locations of their bifurcations. The model demonstrates two ways in which sudden changes can propagate: they can cascade (one causing the next), or they can hop over subsystems. The latter is absent from classic models of cascades. For an application, we study the Arab Spring protests. After connecting the model to sociological theories that have bistability, we use socioeconomic data to estimate relative proximities to tipping points and Facebook data to estimate couplings among countries. We find that although protests tend to spread locally, they also seem to "hop" over countries, like in the stylized model; this result highlights a new class of temporal motifs in longitudinal network datasets.Comment: 20 pages, 4 figures, plus a 6-page supplementary material that contains 5 figures. Accepted at Journal of the Royal Society Interfac

Natural history and management of hepatitis C in East London

PhdChronic infection with the hepatitis C virus infection (HCV) affects over 170 million individuals worldwide. In this thesis the natural history and management of hepatitis C in North- East London was investigated. The prevalence of cirrhosis in patients with chronic hepatitis C rises with increasing duration of infection. In Asian patients infected at birth, infection over 60 years causes cirrhosis in 71 % of infected individuals. Since the rate of fibrosis progression in Asian patients is the same as that seen in Caucasian patients, it is likely that similar rates of cirrhosis will be seen in all patients who are infected with HCV for over 60 years. Factors found to be associated with fibrosis progression were:- age and alcohol excess. Insulin resistance was associated with fibrosis progression. However, elevated serum ferritin or hepatiC iron were not. Knowledge of hepatitis C in the East of London was examined and found to be poor despite the Department of Health information campaign. Educational meetings and postal surveys improved the level of knowledge of HCV. However as our group only assessed knowledge immediately after completion of the sessions, such a testing regime does not address long-term knowledge retention. We examined current and novel management strategies for patients with chronic HCV. Current therapy involves pegylated interferon and ribavirin. We found that insulin resistance was a poor predictor of sustained virological response. Chinese herbal treatments for hepatitis C are widely used but poorly studied. Our group designed a randomised controlled double blind study to assess whether Chinese herbal treatment is effective and results from this study show that recruitment and retention in trials of alternative therapies are problematic and that the herbal remedy had little effect on viraemia and quality of life, although liver function tests did improve a little

Early Influences and Entrepreneurial Intent: Examining the Roles of Education, Experience, and Advice Networks

The independent effects of education, personal experience, and advice networks in the development of new venture creation intent is of considerable interest to educators, researchers, practitioners, and policy makers. Little research, however, has systematically considered the possibility that the relative importance of these factors varies in the early stages of entrepreneurial intent formation. Using a unique dataset (n=963), this study investigates these key relationships at two different points in time. Our results suggest that personal start-up experience and advice networks are particularly influential on the formation of intent to start a new venture, and that a marked shift in significance occurs from the former to the latter

Mass Transfer in Binary Stars using SPH. I. Numerical Method

Close interactions and mass transfer in binary stars can lead to the formation of many different exotic stellar populations, but detailed modeling of mass transfer is a computationally challenging problem. Here, we present an alternate Smoothed Particle Hydrodynamics approach to the modeling of mass transfer in binary systems that allows a better resolution of the flow of matter between main-sequence stars. Our approach consists of modeling only the outermost layers of the stars using appropriate boundary conditions and ghost particles. We arbitrarily set the radius of the boundary and find that our boundary treatment behaves physically and conserves energy well. In particular, when used with our binary relaxation procedure, our treatment of boundary conditions is also shown to evolve circular binaries properly for many orbits. The results of our first simulation of mass transfer are also discussed and used to assess the strengths and limitations of our method. We conclude that it is well suited for the modeling of interacting binary stars. The method presented here represents a convenient alternative to previous hydrodynamical techniques aimed at modeling mass transfer in binary systems since it can be used to model both the donor and the accretor while maintaining the density profiles taken from realistic stellar models.Comment: 10 pages, 10 figures. Accepted for publication in The Astrophysical Journa