Farmer decision making and spatial variables in northern Thailand

This research has two interrelated objectives. The first is to determine the extent to which a relationship exists between farmer characteristics and farming practices in three villages in northern Thailand. The second is to use standard statistical methods for incorporating spatial variables into the analysis and to assess the effects of these variables on farmer decision making. The data base includes information on the location and size of villages, roads, streams, and fields; a digital elevation model with information on elevation, slope, and aspect; and information keyed to individual fields on crops and cropping methods and the ethnicity, income, and religion of farmers. The map data (517 plots) were entered into a computerized geographic information systems (GIS). Results suggest several hypotheses about the relationships between land use and owner characteristics. More significantly, the study concludes that spatial analysis appears to be most useful when the dependent variable is either continuous or ordinal. The outlook is not quite as optimistic when the dependent variable is a nonordinal categorical variable. Before spatial analysis can be applied regularly to social science data, better computational tools need to be developed.     

SOURCES OF VARIABILITY IN PHOSPHORUS AND CHLOROPHYLL AND THEIR EFFECTS ON USE OF LAKE SURVEY DATA1

Summer lake survey measurements of total phosphorus (TP) and chlorophyll a (CHLa) from 188 reserviors and natural lakes in the midwest were analyzed to determine the magnitude of major sources of variability. Median variance among replicate samples collected at the same location and time was about 7-8 percent of the mean for both TP and CHLa. Median observed temporal variability within summers was 27 percent of the mean for TP and 45 percent of the mean for CHLa. Median values of year-to-year variance in average TP and CHLa were 22 percent and 31 percent of the mean, respectively. A range of approximately two orders of magnitude was observed among individual estimates of variance in each of these categories. The magnitude of observed temporal variability was affected only slightly by variance among replicate samples on individual days and was weakly correlated with the length of time during which samples were collected from individual lakes. Observed temporal variation was similar between reservoirs and natural lakes when variances were calculated with logtransformed data. The magnitude of temporal and year-to-year variance can severely limit the power of statistical comparisons of TP and CHLa means, but has less effect on establishing relative rankings of lake means, Sources and relative magnitude of variability are important in the use of TP and CHLa data in regression models and in the planning of lake surveys and subsequent data analysis.     

Managing the potential public health risks from bioaerosol liberation at commercial composting sites in the UK: An analysis of the evidence base

The diversion of biodegradable waste from landfill is of key importance in developing a sustainable waste strategy for the next decade and beyond. The proliferation of waste treatment technologies such as Mechanical Biological Treatment, Anaerobic Digestion and Composting will be paramount in achieving this strategic goal. This paper evaluates the scientific information needed to undertake an effective assessment of the potential public health risks from exposure to bioaerosols in the vicinity of commercial composting activities. Knowledge gaps currently exist in the scientific and regulatory community that limit our ability to effectively characterise source-term emissions, develop reliable dose–response data and accurately model the dispersion of bioaerosols. Consequently reliable risk estimates cannot be developed to inform the management of these potential risks. This uncertainty may prove a barrier to progress in achieving waste diversion and composting targets in Wales and the rest of the UK. A robust and extensive evidence base is required to inform the risk assessment process. This paper advocates the need for further, more focussed research into hazard characterisation of viable and non-viable organisms, improved dose–response data, exposure assessment techniques and an evaluation of the existing risk control and mitigation measures currently adopted. It is hoped that his will enable effective, timely and proportional risk management and mitigation measures to be developed that will foster the confidence required in composting technologies to achieve waste diversion targets and develop sustainable waste strategies.     

Photosynthesis and respiration of exposed salt-marsh fucoids

Photosynthesis and respiration of the salt-marsh fucoids Ascophyllum nodosum ecad scorpioides and Fucus vesiculosus were investigated using an infrared CO₂ gas analyzer under a variety of light intensities, temperatures, and levels of desiccation while the algae were exposed to the atmosphere. Results indicated that net photosynthesis (0.5 to 2.0 mg C/g dry weight/h) saturated rapidly at light intensities (0.1 to 0.2 g cal/cm²/min) which were approximately 10 to 50% of the daily summer maximum intensities for algae found under phanerogam (Spartina alterniflora) canopies. Desiccation exhibited the most pronounced effect on photosynthesis, which increases slightly between 0 and 25% water loss, levels off, and decreases sharply at water losses greater than 50%. Dark respiration (0.1 to 0.3 mg C/g dry weight/h) is also inhibited by desiccation. Both species of algae appear to be broadly adapted to all three parameters investigated.This research was supported by research grants AG-375 and BO 38018 from the National Science Foundation and, in part, by the State University of New York Research Foundation and the Energy Research and Development Administration (ERDA).Communicated by M.R. Tripp, Newark     

X-ray absorption spectroscopy studies of reactions of technetium, uranium and neptunium with mackinawite

Technetium, uranium and neptunium may all occur in the environment in more than one oxidation state (IV or VII, IV or VI and IV or V respectively). The surface of mackinawite, the first-formed iron sulfide phase in anoxic conditions, can promote redox changes so a series of laboratory experiments were carried out to explore the interactions of Tc, U and Np with this mineral. The products of reaction were characterised using X-ray absorption spectroscopy. Technetium, added as TcO4(-), is reduced to oxidation state IV and forms a TcS(2)-like species. On oxidation of the mackinawite in air to form goethite, Tc remains in oxidation state IV but in an oxide, rather than a sulfide environment. At low concentrations, uranium forms uranyl surface complexes on oxidised regions of the mackinawite surface but at higher concentrations, the uranium promotes surface oxidation and forms a mixed oxidation state oxide phase. Neptunium is reduced to oxidation IV and forms a surface complex with surface sulfide ions. The remainder of the Np coordination sphere is filled with water molecules or hydroxide ions.     

Environmental Accountability: Who's Kidding Whom?

International declarations and charters have been produced to encourage and support higher education institutions (HEIs) to address their environmental responsibilities. This paper discusses the results of a critical examination of a range of international HEIs that have signed the global environmental Talloires Declaration. It also assesses the Talloires Secretariat (University Leaders for a Sustainable Future, ULSF) and the extent to which this has been a primary stimulus. An international survey was undertaken and the results presented in a discursive format in order to highlight key driving forces, barriers, and opportunities for environmental responsibility in HEIs. Analysis reveals that they occur on two distinct and evolving levels: the macro national framework level and the micro institutional framework level. Survey responses revealed that none of the HEIs have an embedded institutional environmental culture and most did not have all the micro institutional mechanisms in place for an integrated university-wide environmental response. Many of the institutional barriers to environmental responsibility occurred as a result of this lack of strategy. The most significant institutional opportunity cited was enthusiastic individuals, particularly those at senior management or directorate level, and these individuals were found to be a key driving force. Results also showed that environmental reporting along the lines developed by the private sector is a flexible mechanism that can stimulate progress internally and externally and can be cost effectively disseminated via the World Wide Web. Moreover the survey results indicate that ULSF is not currently a primary stimulus for institution wide action.     

Common criteria for the redefinition of Intermediate Less Favoured Areas in the European Union

This article defines eight key climate, soil and terrain criteria that have been developed for the future delimitation of the Intermediate Less Favoured Areas (LFAs) support, a measure of the Common Agricultural Policy. The LFA scheme has existed since 1975 and is a broad mechanism for improving the viability of agriculture in areas with natural handicaps. The common criteria have been developed for the European Commission's Directorate-General for Agriculture and Rural Development to satisfy the objectives in the Rural Development Policy 2007–2013 (Axis II), which aim to improve the environment and the countryside by more sustainable land management. The criteria were developed by experts, coordinated by the European Commissions Joint Research Centre, to meet the requirement for a robust and harmonised approach of identifying areas that experience natural constraints to agriculture throughout the EU 27 Member States. The criteria proposed are: temperature, heat stress, drainage, soil texture and stoniness, soil rooting depth, soil chemical properties, soil moisture balance and slope. Each criterion is described and an indicative threshold for assessment of its impact on agriculture is provided. The criteria are currently being tested by the EU Member States for a future possible legislation.     

The limits to risk aversion: Part 1. The point of indiscriminate decision

The paper uses utility theory to investigate how much should be spent to avert all costs from an industrial accident apart from direct human harm. These “environmental costs” will include those of evacuation, clean-up and business disruption. Assuming the organisation responsible will need to pay such costs, the difference between its expected utility with and without an environmental protection system constitutes a rational decision variable for whether or not the scheme should be installed. The value of utility is dependent on the coefficient of relative risk aversion, “risk-aversion” for short. A model of an organisation's decision-making process has been developed using the ABCD model, linking the organisation's assets, A, the cost of the protection scheme, B, the cost of consequences, C, and the expected utility difference with and without the scheme, D. Increasing the organisation's risk-aversion parameter will tend to make it less reluctant to invest in a protection system, but can bring about such investment only when the scheme is relatively close to financial break-even. For such borderline schemes, the amount the organisation is prepared to spend on the protection system will rise as the risk-aversion increases. The ratio of this sum to the break-even cost is named the “Limiting Risk Multiplier”, the maximum value of which is governed by the maximum feasible value of risk-aversion. However, the mathematical model shows that increasing the risk-aversion will reduce the clarity of decision making generally. Although the reluctance to invest in a protection scheme may change sign and turn into a positive desire to invest as the risk-aversion increases, the absolute value of this parameter is a continuously decreasing function of risk-aversion, tending asymptotically to zero. As a result, discrimination will gradually diminish, being lost altogether at the “point of indiscriminate decision”. Here the decision maker will be able to distinguish neither advantage in installing the scheme nor disadvantage in installing its inverse. There is a close correspondence between this mathematically predicted state and that of panic, where an individual has become so fearful that his actions become random. The point of indiscriminate decision provides a natural upper bound for the value of risk-aversion. This bounds the Limiting Risk Multiplier in turn, and so sets an objective upper limit on the amount that it is rational to spend on an environmental protection system.