一类守恒律系统中的全局解与有限时间爆破

黎曼不变量是研究守恒律系统的一种重要方法,在许多模型中都有广泛的应用。本文利用该方法,研究了欧拉坐标系下的p系统,获得了几个有关解的全局性和有限时刻爆破的临界条件。     

Processes of auditability in sustainability assurance – the case of materiality construction

This study examines how financial audit-styled concepts such as materiality are transferred to non-financial audit arenas. Drawing on a case study of assurors working within a Big 4 professional services firm, we uncover a number of interrelated features of the materiality determination and assessment process within sustainability assurance (assurance on sustainability reports). We illustrate how assuror flexibility, underpinned by assuror intuition, is central to uncovering assurance technologies deemed capable of addressing the materiality of ambiguous sustainability data. Assurors with no financial audit background retrospectively rationalise their intuition using the assumed authority of structured financial audit methodologies. This facilitates the tentative translation of financial audit knowledge to the sustainability assurance domain. Collaborative, holistic decision-making processes inform the assurors’ continual construction of materiality and are characterised by alliances of (accountant and non-accountant) ‘expert’ assurors merging formal and tacit knowledge. These alliances seek social cohesion within sustainability assurance teams in order to establish a social consensus among assurors around the materiality determination and assessment process. Our analysis develops and extends Power’s theorisation of how new areas are made auditable and advances our understanding of the more practical aspects of non-financial assurance services offered by Big 4 professional services firms.     

In search of thresholds in the household income inequality–growth relationship

This paper investigates the shape of the relationship between household income inequality and economic growth. More precisely we search for the existence of threshold values in this relationship by employing a dynamic panel smooth transition regression model to account for potential endogeneity problems. We find that there do exist threshold values (that are different for different groups of countries): below the threshold, household income inequality is growth enhancing, while above the threshold, inequality has a negative or no effect on economic growth.     

What Determines the Finance-growth Nexus? Empirical Evidence for Threshold Models

This paper elaborates the notion of ``balanced' financial development that is contingent on a country's general level of development. We develop an empirical framework to address this point, referring to threshold regressions and a bootstrap test for structural shift in a growth equation. We find that countries gain less from financial activity, if the latter fails to keep up with or exceeds what would follow from a balanced expansion path. These analyses contribute to the finance and growth literature in providing empirical support for the ``balanced' financial development hypothesis.     

A variable threshold band approach to measuring market linkages

Uncertain and changing economic conditions can have substantial effects on price relationships in spatially separated, linked markets. Although numerous studies have analysed price relationships to characterize market linkage structures, most assume that the relationships and associated linkages are time invariant. This study extends the literature by modelling and estimating time-dependent market linkages that are conditional on changes in exogenous factors. The methodology is used to investigate price relationships in North Carolina (NC) corn and soya bean markets. Empirical results indicate that generalized market-linkage models provide a better representation of price relationships over time, improving the understanding of price discovery dynamics and marketing strategies.     

Analytic value function for a pairs trading strategy with a Lévy-driven Ornstein–Uhlenbeck process

This paper studies the performance of pairs trading strategy under a specific spread model. Based on the empirical evidence of mean reversion and jumps in the spread between pairs of stocks, we assume that the spread follows a Lévy-driven Ornstein–Uhlenbeck process with two-sided jumps. To evaluate the performance of a pairs trading strategy, we propose the expected return per unit time as the value function of the strategy. Significantly different from the current related works, we incorporate an excess jump component into the calculation of return and time cost. Further, we obtain the analytic expression of strategy value function, where we solve out the probabilities of crossing thresholds via the Laplace transform of first passage time of the Lévy-driven Ornstein–Uhlenbeck process in one-sided and two-sided exit problems. Through numerical illustrations, we calculate the value function and optimal thresholds for a spread model with symmetric jumps, reveal the non-negligible contribution of incorporating the excess jumps into the value function, and analyze the impact of model parameters on the strategy performance.     

Bread and Social Justice: Measurement of Social Welfare and Inequality Using Anthropometrics

We address the question of the measurement of health achievement and inequality in the context of variables exhibiting an inverted-U relation with health and well-being. The chosen approach is to measure separately achievement and inequality in the health increasing range of the variable, from a lower survival bound a to an optimum value m, and in the health decreasing range from m to an upper survival bound b. Because in the health decreasing range, the equally distributed equivalent value associated with a distribution is decreasing in progressive transfers, the paper introduces appropriate relative and absolute achievement and inequality indices to be used for variables exhibiting a negative association with well-being. We then discuss questions pertaining to consistent measurement across health attainments and shortfalls, as well as the ordering of distributions exhibiting an inverted-U relation with well-being. An illustration of the methodology is provided using a group of five Arab countries.     

Do UK firms manage earnings to meet dividend thresholds?

This paper examines earnings management by dividend-paying firms in cases where pre-managed earnings would fall below the expected dividend, and by non-dividend paying firms aiming to avoid reporting losses. We find that within the UK market the likelihood of upward earnings management is significantly greater in the former case than the latter, though both are drivers for earnings management. Large firms are less likely to upwardly manage earnings to reach dividend thresholds, consistent with prior UK evidence on the ability of the largest firms to avoid restrictive debt covenants. We also find that earnings management is more clearly observable through examining working capital discretionary accruals than through examining total discretionary accruals.     

Arrovian social choice with psychological thresholds

This paper studies Arrovian preference aggregation rules–the rules satisfying weak Pareto and Arrow’s independence of irrelevant alternatives (IIA)–when individual preferences are nontransitive due to the existence of psychological thresholds — a problem of perceptible difference. A new domain replaces the universal domain, and rationality requirements of social preferences, i.e., transitivity, quasi-transitivity, and acyclicity with indifference transitivity, are converted into the corresponding versions respectively. We show that the Arrovian impossibilities, i.e., dictator, oligarchy, and vetoer theorems, still survive in this setting.     

Spatial Market Integration in the Presence of Threshold Effects

A large body of research has evaluated price linkages in spatially separate markets. Much recent research has applied models appropriate for nonstationary data. Such analyses have been criticized for their ignorance of transactions costs, which may inhibit price adjustments and thus affect tests of integration. This analysis utilizes threshold autoregression and cointegration models to account for a neutral band representing transactions costs. We evaluate daily price linkages among four corn and four soybean markets in North Carolina. Nonlinear impulse response functions are used to investigate dynamic patterns of adjustments to shocks. Our results confirm the presence of thresholds and indicate strong support for market integration, though adjustments following shocks may take many days to be complete. In every case, the threshold models suggest much faster adjustments in response to deviations from equilibrium than is the case when threshold behavior is ignored.