Creating virtual communities of practice for learning technology in higher education: Issues, challenges and experiences

The need for a Web portal to support the rapidly growing field of learning technology has been well established through a number of national surveys and scoping studies over recent years. The overarching vision has been the provision of a virtual environment to assist in informing and developing professional practice in the use of learning technologies. This paper outlines the issues and challenges in creating such a portal through the experiences of developing the RESULTs Network. In the paper, design and participation issues are considered within the wider context of online and networked approaches to supporting practice and professional development. User participation methodologies and technical developments for RESULTs are described in relation to a review of existing representations of practice and a comprehensive survey amongst the learning technology users’ community. An outline of key achievements and experiences is presented, followed by some conclusions regarding the cultural and political issues in creating a viable and sustainable facility and suggestions for possible future direction in national provision

Integrated control of invasive alien plants in terrestrial ecosystems

Effective management of invading alien plants in natural and semi-natural systems is imperative if we are to prevent enormous impacts. An integrated approach involving the combined use of a range of methods is usually necessary to control invasive alien plants effectively. The various methods that are available are usually classified as: mechanical methods (felling, removing of invading alien plants, often in conjunction with burning); chemical methods (using environmentally safe herbicides); and biological control (using species-specific insects and diseases from the alien plant's country of origin). Approaches available for integrated control depend on the species under consideration (features of individual species and the number and identity of species that occur together), features of the invaded systems, the availability of resources and other factors. Mechanical and chemical control are short-term activities, whereas rigorous and disciplined follow-up and rehabilitation are necessary in the medium term. Biological control can provide effective control in the short and medium term in some cases, and it is often the only really sustainable solution in the longer term. We suggest that the biological attributes of plants represent a stable set of attributes, which enable managers to devise control approaches, but that such approaches are likely to be upset by stochastic events such as fires, floods or budget cuts. While an approach of adaptive management, based on trial, error and continual improvement is a logical way in which to progress, the advent of powerful computer simulation modelling technologies will allow managers to do hundreds of 'trial and error' runs in order to explore the consequences of certain courses of action. This should represent an improvement on the current state of affairs, and should allow for better decision-making. We present a series of simulations to illustrate this point.Resource /Energy Economics and Policy,

SOIL MOISTURE MEDIATED BEHAVIORAL AND PHYSIOLOGICAL ALTERATIONS OF COPTOTERMES FORMOSANUS AND RETICULITERMES FLAVIPES (BLATTODEA: RHINOTERMITIDAE)

Substrate moisture is a critical environmental factor for the survival and behavior of subterranean termites (Blattodea: Rhinotermitidae). The invasive Formosan subterranean termite (Coptotermes formosanus) and the native eastern subterranean termite (Reticulitermes flavipes) co-occur in the southeastern United States, but C. formosanus is predominant in subtropical and R. flavipes is more common in temperate regions. The difference in their geographic distributions is largely attributed to their different behavioral and physiological ecology. While ample research has been done on foraging behavior of the two species, there was no empirical evidence for the effects of constant soil moisture on their foraging activity and colony survival. In addition, subterranean termites rely on soil moisture to maintain water balance, and an important physiological mechanism of desiccation resistance in insects is the prevention of transpirational water loss via cuticular hydrocarbons (CHCs). CHCs exhibit plastic response to environmental variations in many insects. Previous research on termite CHCs has analyzed their seasonal and geographical variations as well as the role in chemical communication, however, studies examining CHC plasticity and its correlation with desiccation resistance are lacking. In this study, we investigated the effects of soil moisture on the behavior and physiology of subterranean termites. We hypothesized that foraging activity and survivorship of both C. formosanus and R. flavipes alter in response to different substrate moisture regimes, and the effects differ between the two species. To test this, the tunnel area, survivorship, and food consumption were documented for 28 days under six sand moisture conditions (0%, 1%, 5%, 15%, 25%, 30%) in both C. formosanus and R. flavipes. We found that, in both species, no tunneling or feeding activity was performed at 0% substrate moisture, while no significant difference was found on tunnel area, food consumption, or survivorship among 5%, 15%, 25%, or 30%. Survivorships of termites at 0% and 1% substrate moisture were significantly lower than that at 5%, 15%, and 25% for C. formosanus. For R. flavipes, survivorships at 0% and 1% substrate moisture were significantly lower than that at 5%, 15%, and 30%. In both species, a minimum of 1% substrate moisture is needed for foraging and 5% is required for colony survival. To examine the physiological effects, we further hypothesized that desiccation resistance and CHC profiles of C. formosanus change in response to soil moisture conditions. Upon acclimation to soil moisture conditions of 5%, 15%, and 25%, we found that C. formosanus workers expressed notable changes in CHC profiles in both linear and methyl-branched alkanes, where 12 of the 20 cuticular hydrocarbons detected expressed a significant increase in quantity at 5% soil moisture when compared to 25% soil moisture. Lastly, desiccation resistance of workers was significantly higher upon acclimation to 5% sand moisture (20.36 ± 0.79 hours, survival time under desiccation stress) when compared to 15% (17.47 ± 0.63 hours) and 25% (15.38 ± 0.65 hours). Our results demonstrate the effects of substrate moisture on the behavior and physiology of subterranean termites and suggest that CHC plasticity may be important for the climate adaptation of subterranean termites

A formal evaluation of data flow path selection criteria

A number of path selection criteria have been proposed throughout the years. Unfortunately, little work has been done on comparing these criteria. To determine what would be an effective path selection criterion for revealing errors in programs, we have undertaken an evaluation of these criteria. This paper reports on the results of our evaluation of path selection criteria based on data flow relationships. We show how these criteria relate to each other, thereby demonstrating some of their strengths and weaknesses. In addition, we suggest minor changes to some criteria that improve their performance. We conclude with a discussion of the major limitations of these criteria and directions for future research

Counter-Cyclical Farm Safety Nets

Since the 1920's, the federal government has used an array of farm programs to provide a “safety net” for American agriculture. Farm programs have used price supports, disaster payments, income supports, direct payments, and supply management to provide a safety net for particular markets and producers. This array of farm programs has rarely been organized or managed with the sole purpose of providing a minimum income level to farmers. With the exception of set aside programs, the programs have provided incentives for production and the diversification of production through out the continental United States. While the FAIR Act of 1996 has been generously applauded for allowing producers planting flexibility, maintaining export competitiveness through marketing loan programs, and maintaining production, the Act has been criticized for its lack of a sufficient safety net. All crop insurance programs and marketing loan provisions may be considered safety nets. However, the ad hoc passage of emergency relief in each of the last three years 1998-2000 suggests that these programs have not provided sufficient support to program crop agriculture. The safety net issue, therefore, will likely be a major source of debate in crafting the next farm bill. Can the U.S. government reduce the liquidity problem facing major crop agriculture while pressing the popular provisions of the FAIR Act? Developing a whole farm safety net proposal is one alternative being studied.Agricultural and Food Policy,

AN APPLIED PROCEDURE FOR ESTIMATING AND SIMULATING MULTIVARIATE EMPIRICAL (MVE) PROBABILITY DISTRIBUTIONS IN FARM-LEVEL RISK ASSESSMENT AND POLICY ANALYSIS

Research Methods/ Statistical Methods,

Base and Yield Update Option Analyzer

The Base and Yield Update Option Analyzer (BYA) is a decision support tool for analyzing the economic consequences of the Base Acre and Payment Yield update options in the 2002 farm bill. The BYA is provided by Texas A&M University for educational purposes and is not intended to replace or duplicate the final FSA calculations done for individual farm numbers. The 2002 farm bill offers farmers a one time opportunity to update base and payment yields. The BYA provides a comprehensive system for evaluating the economic consequences of selecting different update alternatives for each farm number before going to the FSA office.Agribusiness, Agricultural and Food Policy, Crop Production/Industries,

FARM BILL STAKEHOLDERS: COMPETITORS OR COLLABORATORS?

Farm Bill, Policy, Deficit, Nutrition, Renewable Energy, Agricultural and Food Policy, Q10, Q18,