Spreads, depths, and the impact of earnings information: an intraday analysis

For a sample of NYSE firms, we show that wide spreads are accompaniedby low depths, and that spreads widen and depths fall in responseto bigger volume. Spreads widen and depths fall in anticipationof earnings announcements; these effects are more pronouncedfor announcements with larger subsequent price changes. Spreadsare also wider following earnings announcements, but this effectdissipates quickly after controlling for volume. Collectively,our results suggest liquidity providers are sensitive to changesin information asymmetry risk and use both spreads and depthsto actively manage this risk.     

Health and development: The Venda care group organisation

Health is one of the crucial problems confronting the development of Third World countries. Community‐based primary health care is the best instrument for mobilising community development.Development through health, however, can only be achieved if primary health care is implemented in a comprehensive approach in which a supportive environment and living conditions are as important as the provision of health care services. The Venda care group organisation, like other village health workers, is involved in primary health care and community development in the communities of the care groups. Such supportive community‐based organisations are able to alleviate health and development problems at the grass roots provided that programmes and activities are based on community participation, self‐reliance and the development of local decision‐making and leadership skills. The degree of success of the Venda care group organisation in achieving these objectives was investigated.     

Trends in fall injuries associated with children's outdoor climbing frames

Falls from publicly owned climbing equipment are often cited as the major cause of injury on children's outdoor playgrounds and have been the focus of substantial interventions in the UK since the early 1980s. Analysis of national data on falls from climbing frames for 1988 to 2002 shows that the main discernible trend during this period is an increase in the occurrence of injuries to the lower arm. Whether this is attributable to a behavioural response to some of the interventions, or to some other factor, is unknown.     

All consuming surveillance: surveillance as marketplace icon

With consumers and their activities routinely visible through online, mobile and social media, to both their peers and to corporations, this article examines surveillance as a marketplace icon. Surveillance is central to the construction of consumers and markets. Many contemporary marketing practices are surveillant as they rely on the collection, analysis and application of consumer data to place advertising, define market segments and to nudge consumer behaviours. Consumer surveillance is also an enactment of corporate power, attempting to align individual preferences with corporate goals. The historical origins of surveillance and the emergence of the surveillance–industrial–entertainment complex are explored, which highlights how surveillance, as well as a process for defining markets is also an object of consumption. The future sees a huge struggle for consumer data between two great centres of surveillance power – the state and the corporation – as they battle over data use for national security.     

Environmental factors of food literacy in Australian high schools: views of home economics teachers

This study set out to examine environmental factors impacting on the food literacy of adolescents. It utilized data from a nation‐wide survey of home economics teachers regarding their experience of food literacy education in Australian high schools. Content analysis and the ANGELO framework were applied to analyse free‐text comments from 78 of the respondents that were collected as part of a more extensive data set. The analysis of environmental factors revealed three enablers and ten barriers that could influence food literacy education delivered by high schools in Australia. High schools are well positioned to improve adolescents’ food literacy through a comprehensive, hands‐on approach in home economics. However, many environmental barriers were reported that could influence food literacy education in Australian high schools such as: lack of teaching materials and facilities, and human resources; the perceived inadequacy of the Australian school curriculum; non‐supportive school canteens; and negative role modelling. This study points to the need to eliminate or reduce these environmental barriers impacting on the capacity for effective food literacy education in high schools to help adolescents increase their food literacy and thereby support them in making informed food choices.     

Optimal route decision with a geometric ground-airborne hybrid model under weather uncertainty

Adverse weather is the dominant cause of delays in the National Airspace System (NAS). Since the future weather condition is only predictable with a certain degree of accuracy, managing traffic in the weather-affected airspace is a challenging task. In this paper, we propose a geometric model to generate an optimal combination of ground delay and route choice to hedge against weather risk. The geometric recourse model (GRM) is a strategic Probabilistic Air Traffic Management (PATM) model that generates optimal route choice, incorporating route hedging and en-route recourse to respond to weather change: hedged routes are routes other than the nominal or the detour one, and recourse occurs when the weather restricted airspace becomes flyable and aircraft are re-routed to fly direct to the destination. Among several variations of the GRM, we focus on the hybrid Dual Recourse Model (DRM), which allows ground delay as well as route hedging and recourses, when the weather clearance time follows a uniform distribution. The formulation of the hybrid DRM involves two decision variables - ground delay and route choice - and four parameters: storm location, storm size, maximum storm duration time, and ground-airborne cost ratio. The objective function has two components: expected total ground delay cost and expected total airborne cost. We propose a solution algorithm that guarantees to find the global optimum of the hybrid-DRM. Based on the numerical analysis, we find that ground-holding is effective only when combined with the nominal route. Otherwise, it is optimal to fly on the route determined by the DRM without ground delay. We also find the formula of the threshold ground-airborne cost ratio, which we call the Critical Cost Ratio (CCR), that determines the efficacy of ground delay: the higher the CCR, the more effective the strategies involving ground delay. We conclude that both ground delay and route hedging should be considered together to produce the best ATM decisions.     

Efficiency with costly information: a reinterpretation of evidence from managed portfolios

We investigate the informational efficiency of mutual fund performancefor the period 1965-84. Results are shown to be sensitive tothe measurement of performance chosen. We find that returnson S&P stocks, returns on non-S&P stocks, and returnson bonds are significant factors in performance assessment.Once we correct for the impact of non-S&P assets on mutualfund returns, we find that mutual funds do not earn returnsthat justify their information acquisition costs. This is consistentwith results for prior periods.     

The specialist's discretion: stopped orders and price improvement

When a market order arrives, the NYSE specialist can offer aprice one tick better than the limit orders on the book andtrade for his own account. Alternatively, the specialist can'stop' the market order, which means he guarantees executionat the current quote but provides the possibility of price improvement.My model shows that specialists can use stops to sample thefuture order flow before making a commitment to trade. I presentempirical evidence that both stops and immediate price improvementimpose adverse selection costs on limit order traders.     

Does purchasing power parity hold in African less developed countries? Evidence from a panel data unit root test

This study tests for long-run relative purchasing power parityamong a sample of 27 African less developed countries. For thispurpose, a new test advocated by Im and co-workers is employedwhich allows one to test for unit roots in heterogeneous paneldatasets. This is known as the t-bar test, by which purchasingpower parity is confirmed or rejected on the basis of whetheror not the average augmented Dickey-Fuller statistic based ondemeaned data is significantly different from zero. Using quarterlydata covering the period 1974-97, purchasing power parity isgenerally rejected using individual country unit root testsbut support is found using the t-bar test. This suggests thatlow power problems in testing for purchasing power parity canbe overcome using this panel data procedure. The findings alsosupport the view that purchasing power parity is most likelyto be found among high inflation less developed countries andthat the half-life of a one-off random shock to parity is approximatelysix quarters. These results are generally confirmed for the1960-73 period.     

Small is beautiful — the key concept for successful irrigation development∗

Generally small schemes are more beneficial than large schemes, with fewer management and money problems. An attempt is made to analyse the components of large and small irrigation developments in order to expose and compare the causes of success or failure.