A special section for correspondence and controversy

H.R. 4300, The Family Unity and Employment Opportunity Act of 1990.     

Interactions between birds, fruit bats and exotic plants in urban Hong Kong, South China

I observed the use of exotic plant species by native birds and bats in 8 km² of urban Hong Kong. Twenty-nine plant taxa were used repeatedly. Five species accounted for most interactions with birds: Cinnamomum camphora (10 bird species), Ficus religiosa (6), Livistona chinensis (7) and Pyracantha crenulata (6) provided fruits, while Bombax ceiba (6) supplied nectar. Panicum maximum (2) and C. camphora (1) provided seeds for granivorous birds and Leucaena leucocephala is host to a psyllid consumed by small insectivores in winter. Most trophic interactions between exotics and fruit bats involved the fruits or flowers of Syzygium jambos, while Livistona chinensis provided roosting sites for Cynopterus sphinx. The fruiting phenologies of the exotic species differed from the local flora, with fruit of some species available for the majority of the year. Fruit characteristics for the most commonly eaten species are within the range for native fruit species, although most are larger and have a lower seed load than the medians for native species. Seed dispersal by birds and/or fruit bats is a necessary, but not sufficient, condition for the naturalization of fleshy-fruited plants in Hong Kong, but S. jambos is the only naturalizing exotic species that needs vertebrates for pollination.     

Random field models in image analysis

Image models are useful in quantitatively specifying natural constraints and general assumptions about the physical world and the imaging process. This review paper explains how Gibbs and Markov random field models provide a unifying theme for many contemporary problems in image analysis. Random field models permit the introduction of spatial context into pixel labeling problems, such as segmentation and restoration. Random field models also describe textured images and lead to algorithms for generating textured images, classifying textures, and segmenting textured images. In spite of some impressive model-based image restoration and texture segmentation results reported in the literature, a number of fundamental issues remain unexplored, such as the specification of MRF models, modeling noise processes, performance evaluation, parameter estimation, the phase transition phenomenon, and the comparative analysis of alternative procedures. The literature of random field models is filled with great promise, but a better mathematical understanding of these issues is needed as well as efficient algorithms for applications. These issues need to be resolved before random field models will be widely accepted as general tools in the image processing community.     

'Management Standards' work-related stress in the UK: practical development

Research commissioned for the UK's Health & Safety Executive (HSE) supports the view that a preventative, risk-assessment based approach would be more effective than case-based methods in achieving a nationwide reduction in work-related stress. The background to this approach is described and discussed in a companion paper in this issue (Mackay, Cousins, Kelly, Lee, & McCaig, 2004). The present paper describes the development of HSE's new stress Management Standards—which offer organizations continuous improvement through a three-phase stress preventative process—and the development of a supporting 'Indicator Tool' (a two-phase questionnaire to assess employee perceptions of working conditions). The Management Standards comprise a series of 'states to be achieved', which are statements of good practice in six key stressor areas: demands, control, support, relationships, role and organizational change. For each stressor area there is also a 'platform statement' that outlines the main aims to be achieved by the organization. This statement may include a target percentage of employees finding that the organization meets the standard: this matter will be settled after the standards have been assessed in a public consultation campaign. To use the new process, an organization's state can first be assessed using the Indicator Tool; liaising with workers in focus groups enables a further exploration of issues raised; finally, there may be formulation of interventions and subsequent review. It is not intended that the standards will be legally enforceable. HSE's aim is that they and the associated methodology will enable organizations to effectively tackle work-related stress, and subsequently reduce both its incidence and prevalence.     

Variations in Child Care by Grandparents During the First Three Years

Routine child care by grandparents was examined for 1,229 children who were participants in the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care. Four groups were identified: extended full‐time care, extended part‐time care, sporadic care, and no routine care during the first three years. The odds of sporadic child care by grandparents were higher when mothers were relatively young and worked nonstandard hours. The odds of extended full‐time grandparent care versus extended part‐time grandparent care were higher for mothers of color and mothers with more extensive full‐time employment. All types of grandparent care were more likely when a grandparent lived in the household. These findings suggest that grandparent care is heterogeneous and may occur in response to different family circumstances.     

Adapting to Climate: A Case Study on Riverine Flood Risks in the Netherlands

Climate change may well lead to an increased risk of river floods in the Netherlands. However, the impacts of changes in water management on river floods are larger, either enhancing or reducing flood risks. Therefore, the abilities of water-management authorities to learn that climate and river flows are changing, and to recognize and act upon the implications, are of crucial importance. At the same time, water-management authorities respond to other trends, such as the democratization of decision making, which alter their ability to react to climate change. These complex interactions are illustrated with changes in river flood risk management for the Rhine and the Meuse in the Netherlands over the last 50 years. A scenario study is used to seek insight into the question of whether current water-management institutions and their likely successors are capable of dealing with plausible future flood risks. The scenarios show that new and major infrastructure is needed to keep flood risks at their current level. Such a structural solution to future flood risks is feasible, but requires considerable political will and institutional reform, both for planning and implementation. It is unlikely that reform will be fast enough or the will strong enough.     

创新行为如何影响政府绩效:以领导干部任前公示为例的研究探索

在以往关注不同类型创新行为对组织绩效影响的研究中,组织氛围与沟通、人力资源与管理和行政成本是三类较为常见的影响因素,但三者尚未综合形成统一的框架。本研究选取了领导干部任前公示这一以人力资源管理为内容的创新行为,构建了三因素影响组织绩效的过程假设。通过分析问卷调查数据,发现三因素之间存在显著的相关性,且若按照组织边界划分绩效内容,三因素均与组织的内部成长建设绩效显著相关,而同组织外部绩效水平相关程度较弱。依此认为,创新行为影响绩效是一个由人、财、物三因素互动,并依据创新本身特点内容有所侧重的过程。