Combinatorial conditions that imply word-hyperbolicity for 3-manifolds

Thurston conjectured that a closed triangulated 3-manifold in which every edge has degree 5 or 6, and no two edges of degree 5 lie in a common 2-cell, has word-hyperbolic fundamental group. We establish Thurston's conjecture by proving that such a manifold admits a piecewise Euclidean metric of non-positive curvature and the universal cover contains no isometrically embedded flat planes. The proof involves a mixture of computer computation and techniques from small cancellation theory.Comment: (21 pages) To appear in Topolog

US Oil Price Exposure: The Industry Effects

This paper investigates the exposure of industry level portfolios to oil price shocks. Our paper utilizes the Campbell (1991) decomposition of stock returns based on a log-linear approximation to the discounted present value relation while allowing for time varying expected returns. The results from our baseline regressions indicate that there is little sensitivity in industry level portfolios to unexpected movements in oil prices, with the gold, oil & gas and retail industries being the only exception. In contrast, based in the Campbell (1991) decomposition, we identify extensive exposure to oil prices in industry level returns in particular channels. The extent of the exposure is particularly significant for a number of the industries, with positive (negative) permanent implications for gold, and the oil and gas industries (retail and meals, restaurants and hotels).Oil, Industry Stock Returns, Vector autoregression

A simple bivariate count data regression model

This paper develops a simple bivariate count data regression model in which dependence between count variables is introduced by means of stochastically related unobserved heterogeneity components. Unlike existing commonly used bivariate models, we obtain a computationally simple closed form of the model with an unrestricted correlation pattern.

More on F versus t tests for unit roots when there is no trend

Rodrigues and Tremayne (2004) interpret a problematic size result in a Monte Carlo study reported in Elder and Kennedy (2001) as arising from Elder and Kennedy's use of an inappropriate testing equation. In expositing their result, Rodrigues and Tremayne inadvertently lead readers to believe that the Elder and Kennedy conclusion is in error. We clarify the Rodrigues and Tremayne contribution, putting the validity of the Elder and Kennedy result in proper perspective and underlining the important role played by the starting value in Monte Carlo analyses.

F versus t tests for unit roots

F tests which test jointly for a unit root and a zero intercept, and so compete against Dickey-Fuller t tests, are shown not to enhance power because they are invariant to the intercept value in the absence of a unit root. Monte Carlo results in the literature that indicate otherwise are shown to have resulted from the use of special starting values. Testing procedures that employ these F tests to enhance power should be revised.Dickey-Fuller

Macroeconomic Uncertainty and Performance in Asian Countries

We use a very general bivariate GARCH-M model and quarterly data for five Asian countries to test for the impact of real and nominal macroeconomic uncertainty on in°ation and output growth. We conclude the following. First, in the majority of countries uncertainty regarding the output growth rate is related negatively to the average growth rate. Second, contrary to expectations, infation uncertainty in most cases does not harm the output growth perfor- mance of an economy. Third, in°ation and output uncertainty have a mixed effect on inflation. Consistent results are found using the VAR-GARCH-M approach to investigate the dynamic relationship between in°ation and output growth using impulse response functions. This evidence implies that macroeconomic uncertainty may even improve macroeconomic performance, i.e., raise output growth and reduce inflation. Our empirical results highlight important differences with those for industrialized countries.Inflation, Output growth, Uncertainty, GARCH models

Oil Volatility and the Option Value of Waiting: An analysis of the G-7

There has recently been considerable interest in the potential adverse effects associated with excessive uncertainty in energy futures markets. Theoretical models of investment under uncertainty predict that increased uncertainty will tend to induce firms to delay investment. These models are widely utilized in capital budgeting decisions, particularly in the energy sector. There is relatively little empirical evidence, however, on whether such channels have industry-wide effects. Using a sample of G7 countries we examine whether uncertainty about a prominent commodity — oil — affects the time series variation in manufacturing activity. Our primary result is consistent with the predictions of real options theory — uncertainty about oil prices has had a negative and significant effect on manufacturing activity in Canada, France, UK and US.Oil, Volatility, Vector autoregression, Multivariate GARCH-in-Mean VAR

The History of the Master Builders Association of NSW: The First Hundred Years

The study of employer associations in Australia has focused on the activities of state employers’ federations and peak employer organisations in the federal sphere and on the effect on those organisations of Australia’s compulsory conciliation and arbitration system. The majority of literature has continued to mainly focus on national employer associations and on their difficulties in achieving national unity due to the differing views of their State branches. Despite their historic relevance, state employer associations that were established during the colonial era have been virtually ignored. Whilst single industry associations at the state level have also had to come to terms with the demands of Australia’s dual industrial relations systems, the role of the state systems and of the state-based employer associations appear to have attracted comparatively little academic interest. The effect on employer associations of the character and status of those who direct and influence their operations has received little, if any, analysis. Leading builders who were the major contractors of their time established the Master Builders Association of NSW (MBA/NSW) during the colonial era, and those that led the association throughout the turmoil of the 1890s, a major depression and two world wars continued to be the leading builders in the State of New South Wales. Following the Second World War, the character of the MBA/NSW changed with the absorption of suburban associations that comprised small to medium-sized builders. That development was compounded by the changes in the size, height and complexity of buildings within the Central Business District of Sydney and in other centres throughout the metropolitan area. Enormous capital was required to fund construction works and large corporations were formed and the bench-mark of what constituted a major contractor was raised considerably. Those events had an enormous impact on the character and operations of the MBA/NSW. This historical thesis seeks to explain why the MBA/NSW was successfully established in 1873 after two previous attempts; and, what accounts for its subsequent survival and growth. It analyses the various challenges that faced the MBA/NSW during its first one hundred years and the effect on that association of the policies and practices of iii architects, governments, trade unions and other employer associations. It traces the 1890 establishment of the Master Builders Federation of Australia (MBFA), the oldest federal industry association in Australia, by the MBA/NSW and its sister associations from other areas of Australia and analyses the manner in which the State-based Master Builders Associations each fought to retain their individual independence and reject any attempts to cede their powers so as to convert their federation into a national centralised body. The need for quick national responses of major building companies during the 1970s was addressed through a composite organization created by the Master Builder movement and the Australian Federation of Construction Contractors due to the continued refusal of the Master Builders associations to cede their powers to MBFA. The development of the trade union movement in the building industry in New South Wales is also analysed together with reference to the history of building industry awards in this State. The study also outlines the history of MBA/NSW initiatives and policies related to tendering and industrial relations which came under increasing pressure due to legal challenges from disciplined members and to changes arising from industrial and trade practices legislation. The practice of convening tender meetings, the introduction of Builders Licensing in New South Wales and, the origins of the MBA/NSW Group Apprenticeship Scheme are each described

THE AUSTRALIAN BUILDING CONSTRUCTION EMPLOYEES & BUILDERS LABOURERS FEDERATION AND THE NEW SOUTH WALES BUILDING INDUSTRY

Australia, during the twenty five years that followed the end of the Second World War, experienced increased prosperity and a stable industrial relations system in which the Commonwealth Conciliation and Arbitration Commission (the federal commission) played a dominant and authoritative role. The NSW building boom which began in the latter part of the 1950s introduced new technology, concentrated building workers in the central business district of Sydney, and broadened the range of skills required of builders' labourers. The major NSW building tradesmen's union, the Building Workers' Industrial Union (NSW/BWIU), had a communist leadership. The national body of that union lost its federal industrial registration in 1948, and the NSW/BWIU moderated its behaviour after it nearly lost its own, NSW state, registration in 1957. The Australian Building Construction Employees and Builders' Labourers Federation (ABLF) had a federal award under which most of the members of its NSW branch (NSW/BLF) were employed. The leadership of both the ABLF and of the NSW/BLF were communist. The Communist Party of Australia (CPA) suffered a defection by the ABLF leadership in the early 1960s to a communist party which endorsed Marxist- Leninist policies. The BWIU leadership also left the CPA (and formed the Socialist Party of Australia) following an announced shift in policy direction by the CPA in 1969. That shift in policy abandoned the `united front' concept and adopted ultra-left policies which advocated vanguard action by small groups. The announcement by the CPA of its new policies occurred after the gaoling of a Victorian union leader which signalled the virtual collapse of the previously authoritative, and punitive, role of the federal commission. The structure and politics of society underwent enormous change during the 1960s and early 1970s which was an era of protest during which various social movements were formed. The NSW/BLF became a major participant in those protests and movements, and conducted various industrial and social campaigns during the first half of the 1970s. Those campaigns were conducted in line with the ultra-left policies of the CPA, and this isolated the NSW/BLF from its federal body and from the trade union movement generally. This thesis analyses some of the campaigns conducted by the NSW/BLF during the period 1970-1974 and the various responses by the Master Builders Association of NSW (MBA/NSW) to those campaigns. The MBA/NSW broadened its membership base during the 1950s, and the effect that its new membership structure had on its decision-making processes is also considered

A REEXAMINATION OF FRACTIONAL INTEGRATING DYNAMICS IN FOREIGN CURRENCY MARKETS

This paper reexamines foreign currency markets for evidence of fractional integration, and extends the extant literature in several important dimensions. First, we utilize a new semiparametric wavelet-based estimator, which is far superior to the more prevalent GPH estimator on the basis of mean squared error. Second, we utilize a broader and longer sample, which better facilitates the detection of long memory dynamics. Our analysis yields interesting empirical results that contrast with other recent studies. In particular, we find new evidence that a large proportion (fourteen out of nineteen) of exchange rate series display evidence of long memory, with little variation over alternative sample periods.Financial Economics,