Statistical control of hygienic quality of bathing water

In Denmark the hygienic quality of the bathing water has been controlled, based on general guidelines since 1978. Today more than 1100 control sites in marine areas have been established to ensure safe bathing water quality. According to EEC directives and Danish tradition, the control is usually performed by measuring the content of the indicator bacteria Escherichia coli (E. coli) in 5 to 20 test samples each bathing season.In Denmark, control programmes and data are evaluated using basic statistical quality control principles. This paper presents general guidelines for bacterial control, their statistical background and practical application. Furthermore, the evaluation and application of a specific programme for control of Staphylococcus aureus (S. aureus) are presented. This programme was used in a Danish bay where the authorities prescribe direct control of these potentially harmful bacteria.     

The past impact of livestock husbandry on dispersal of plant seeds in the landscape of Denmark

The recent decline in species richness in (semi)-natural habitats in northern Europe has largely been attributable to habitat destruction, and to subsequent limitation in seed dispersal among fragments. However, some habitat types were probably split up already in the historical landscape, but the segregated parts were probably not isolated to the present degree. This paper seeks evidence for livestock as vectors for propagules at 3 spatial scales in the past cultural landscape. Three main scales at which livestock acted as seed dispersers are important: free movement in the landscape (1-10 km), driving animals to mast feeding or to manors (10-50 km), and the export of living animals (hundreds of km). The emerging picture is for most plant species a dramatically decreased chance of dispersal in the modern landscape. The consequence is probably decreasing species richness in (semi)-natural plant communities, such as pasture, meadow, and heathland.     

Specific floater home ranges and prospective behaviour in the European starling,<Emphasis Type="Italic"> Sturnus vulgaris</Emphasis>

In many bird species, floaters are present on the breeding grounds in one or more years before they breed. There is increasing evidence that they have specific home ranges in which they search for information about current and future breeding opportunities. We investigated the role of prospecting in a migratory European starling (Sturnus vulgaris) population. Radio-tracking showed that male starling floaters use specific home range areas during the breeding period. Nest-box observations demonstrated that non-parental nest intrusion is common in the starling and that it is significantly more frequent during the nestling than during the incubation period. In addition, small groups of nest boxes were more likely to be occupied by starlings if they had been put up during the preceding breeding season. The results suggest that floaters try to acquire information about local breeding communities. One specific type of information may be the location of potential breeding sites.     

波罗的海的有害物质管理:成果与挑战

能够在生物体内累积的、具有持续性和毒性的有害物质流入波罗的海是一个重要的涉及环境和人类健康的问题.为解决这一问题,主要在赫尔辛基委员会(HELCOM)之下进行了多方努力.本文对HELCOM在有害物质方面所作的努力进行了考查,并讨论了将来在有害物质管理方面面临的挑战.本文认为,尽管还有一些遗留问题和困难需要解决,但过去在控制有害物质方面所做的工作已在改善波罗的海环境质量和减少影响人类健康的风险方面起到了积极的作用.特别是确定了今后HELCOM在对有害物质的管理中面临的四个挑战并对其进行了论述,它们是[1]需要进一步执行并加强公、私部门的能力;[2]需要提高该地区及国际论坛中资料的可用性、质量和可比性;[3]需要巩固现有法规并编入新的问题;[4]需要有效协调HELCOM的活动与其它国际论坛为控制有害物质所做的努力之间的关系.     

Biodegradation of 4-nonylphenol in seawater and sediment

Biodegradation of 14C-labelled nonylphenol at the concentration 11 microg litre (-1) in seawater has been estimated by collection and quantification of the formed labelled carbon dioxide. Initially degradation was very slow but when the microorganisms had become adapted, after four weeks at 11 degrees C, the degradation rate increased rapidly and after 58 days about 50% of 14C from NP was found in the CO2 fraction. In the presence of sediment the initial degradation rate was high and did not increase after longer incubation. Lack of oxygen reduced the degradation rate by half in the presence of sediment.     

Alcohol problems among Swedish drunk drivers: differences related to mode of detection and geographical region

OBJECTIVE: To investigate the prevalence of alcohol problems in a representative sample of Swedish drivers suspected of drunk driving in comparison with control drivers and the general Swedish population in relation to mode and time of detection. Is the time of day or night or the detection mode important for the prevalence of alcohol problems and which are the best predictors for identifying alcohol problems among DUI offenders? METHODS: Two thousand and one hundred drivers (169 females) suspected of DUI offence during 1997-2001 who agreed to respond to the AUDIT questionnaire (Alcohol Use Disorders Identification Test) and 785 control drivers (266 females) not suspected of DUI recruited at general traffic controls were investigated. RESULTS: Both mode and time of detection were found to be important. The greatest impact on the prevalence of alcohol problems emanated from the predictors in the following order: high BAC; unlicensed driving; detection hours between 12.00 and 18.00, and age under 26 years. Age over 55 years and detection in general traffic controls were the two strongest factors negatively correlated to alcohol problems prevalence. The differences between regions with regard to alcohol problems incidence could only partly be explained by police routines and resources. CONCLUSIONS: Mode and time of detection affect the prevalence of DUI offenders with alcohol problems, and to a lesser degree also BAC level. Both the detection mode and the time of detection are significant for the proportion of identified DUIs with alcohol problems. Because the majority of committed DUI offenses are never identified, it is important to optimize the detection strategies of the police with the purpose of minimizing public damage and expenses.     

Mutual information in the Tangled Nature model

We consider the concept of mutual information in ecological networks, and use this idea to analyse the Tangled Nature model of co-evolution. We show that this measure of correlation has two distinct behaviours depending on how we define the network in question: if we consider only the network of viable species this measure increases, whereas for the whole system it decreases. It is suggested that these are complimentary behaviours that show how ecosystems can become both more stable and better adapted.     

The role of environmental and spatial factors for the composition of aquatic bacterial communities

This study investigates the importance of local vs. spatial factors on bacterial community composition of 35 rock pools at the Baltic Sea coast. The pools were located in five distinct spatial clusters over a total scale of <500 m and differed widely in terms of water chemistry. To determine the fractions of the variance in bacterial community composition (BCC) between rock pools that are explained by local environmental vs. spatial factors, a variance partitioning procedure using partial canonical correspondence analysis was performed. Three environmental variables (salinity, chlorophyll a concentration, and water color) had a significant effect on BCC, irrespective of the spatial location of the pools. Vice versa, there was a significant effect of spatial factors on BCC irrespective of any of the environmental factors included in this study. Hence, the patchy spatial distribution of the pools was partly reflected in the composition of the bacterial communities in the pools, which might be caused by congruent colonization events of adjacent pools, such as simultaneous seaspray inputs or direct exchange of bacteria via connecting rivulets. This study shows that the composition of planktonic bacteria can show provincialism at small spatial scales, which is likely to be caused by environmental conditions as well as historical events.     

GENETIC PROGRAMMING AND ITS APPLICATION IN REAL‐TIME RUNOFF FORECASTING1

ABSTRACT: Genetic programming (GP), a relatively new evolutionary technique, is demonstrated in this study to evolve codes for the solution of problems. First, a simple example in the area of symbolic regression is considered. GP is then applied to real‐time runoff forecasting for the Orgeval catchment in France. In this study, GP functions as an error updating scheme to complement a rainfall‐runoff model, MIKE11/NAM. Hourly runoff forecasts of different updating intervals are performed for forecast horizons of up to nine hours. The results show that the proposed updating scheme is able to predict the runoff quite accurately for all updating intervals considered and particularly for updating intervals not exceeding the time of concentration of the catchment. The results are also compared with those of an earlier study, by the World Meteorological Organization, in which autoregression and Kalman filter were used as the updating methods. Comparisons show that GP is a better updating tool for real‐time flow forecasting. Another important finding from this study is that nondimensionalizing the variables enhances the symbolic regression process significantly.