Assessing the quality of water quality assessments: An analytical quality control protocol for benthic diatoms

In this paper, the background to the development of an analytical quality control procedure for the Trophic Diatom Index (TDI) is explained, highlighting some of the statistical and taxonomic problems encountered, and going on to demonstrate how the system works in practice. Most diatom-based pollution indices, including the TDI, use changes in the relative proportions of different taxa to indicate changing environmental conditions. The techniques involved are therefore much simpler than those involved in many studies of phytoplankton, for example, where absolute numbers are required

Heavy metals and aquatic bryophytes: accumulation and their use as monitors

An experimental study was made of accumulation and loss of heavy metals by the aquatic moss Rhynchostegium riparioides and of the processes involved. The information gained were used to assess the effectiveness of this species as a monitor. Growth of Rhynchostegium continued throughout the year with peaks in spring and autumn. There were positive correlations between growth and water and air temperatures. Strong differences in growth rates in the four streams were not related to nutrient or heavy metal concentrations. Various patterns of mesh bag were tested as containers for transplanted Rhynchostegium to be used as a monitor. No significant differences in accumulation by moss were found between boulders or bags, or in accumulation with different patterns of bags. Accumulation was reduced slightly at the centre of bags packed with large quantities of moss. The physiology of Zn accumulation was also studied. A large part of accumulation (> 70%) in the early stages (< 12 h) was in a form readily exchanged for competing cations such as Ca and Ni; over longer time periods there was significant accumulation into a more tightly bound compartment. There was no evidence that uptake into this latter compartment was under the direct control of the plant's metabolism. There was differential accumulation of Cr(III) and Cr(VI) in laboratory experiments; during a case study it was possible to "predict" the speciation of Cr in the water by the concentrations accumulated by the moss. These results confirm that bryophytes are useful as monitors of heavy metal pollution in a wide range of circumstances. A range of such applications are outlined, along with recommendations for standard methods for using moss bags

Informing Coalition Structure Generation in Multi-Agent Systems Through Emotion Modelling

We propose a hybrid coalition formation method for multi-agent systems that combines a rational mechanism and an emotionally-inspired mechanism to reduce the associated computational cost. To initialise coalition formation, the rational mechanism is used and in subsequent iterations, the emotional mechanism (that forms coalitions resulting from emotional reactions to aspects of interactions between agents) is used. The emotions of anger and gratitude are modelled and used as a basis to model trust which is in turn used to restrict the coalition state-space. We offer some discussion as to how this hybrid method offers an improvement over using a method that only considers payoff maximisation and we propose some direction for future work

The semiotics of slime: visual representation of phytobenthos as an aid to understanding ecological status.

&lsquo;Ecological status&rsquo; is a core concept of the Water Framework Directive (WFD).&nbsp; Many papers have been published throughout Europe describing methods for assessing ecological status by comparing observed assemblages with those expected under unimpacted conditions.&nbsp; However, the quantitative rigour necessary to develop these methods has been achieved by reducing complex community structure to simple metrics.&nbsp; One of the costs associated with this is the loss of higher level understanding of community structure which otherwise may have informed data interpretation.&nbsp; It also pushes the debate about ecological status further into the realm of abstract scientific ideas and away from engagement with stakeholders, another core concept of the WFD.&nbsp; These matters are particularly acute for microscopic organisms such as the algae, which play a key role in freshwater ecosystem functioning but are little known beyond a narrow group of specialists.&nbsp; Examples of phytobenthos communities from streams and rivers in the UK are used to show how visual representation can inform both peer-to-peer debate within the scientific community and communication with non-technical stakeholders

Modelling emotions and simulating their effects on social interactions in agent systems

Agent-based decision-making usually relies upon game theoretic principles that are ``rational'' i.e. decision-making is purely mathematical based on utilities such as the wealth of an agent. In the context of public goods games, such reasoning can often lead to non-optimal, destructive outcomes for both individuals and the total system, as shown in many scenarios from game theory. This thesis considers how the use of \textit{emotions} can impact upon decision-making and social interactions amongst agents in the iterated Prisoner's Dilemma game by modelling emotions in a functional manner. The background to the thesis is first presented in chapters 2 and 3 where the argument for emotions being included in agent-based decision-making, and evidence to support this proposition, is outlined. Various philosophical issues are also considered such as: do emotions directly motivate an agent's intentional behaviour and, is an agent's decision-making still rational if emotions are used? The framework developed to allow for modelling of emotions in agents is then discussed in chapters 4 and 5 where major psychological models of emotion and computational implementations thereof are discussed. Finally chapters 6 to 8 present extensive investigations into how the emotions modelled using the framework affect social interactions amongst agents in the context described above. As of yet, this topic has been relatively unexplored by computer science and there is space for novel, interesting contributions to be made, these contributions are outlined below. In chapter 6 the emotions of \textit{anger} and \textit{gratitude} are modelled and their effects upon social interactions are analysed. In particular, I look at whether agents endowed with these emotions offer any improvement upon the success of agents using with the ``tit-for-tat'' strategy when playing against other leading strategies from Axelrod's famous computer tournament. How these emotions affect rates of cooperation/defection and the fairness of individual scores is considered along with why they do so. This investigation is furthered in chapter 7 where \textit{admiration} is modelled and an investigation is performed into what emotional characters are selected for under different initial conditions and why. This examination provides a discussion regarding what emotional social norms emerge in a population when agents admire the individual success of others. Two salient questions are asked: is it is the case that emotional characters which promote the total wealth of the system are selected for as an emergent property and, do different initial conditions affect the emotional characteristics selected for?. Finally, chapter 8 extends chapter 7 by modelling \textit{hope} and enquires as to how particular emotional character populations (after a complete social norm has been established) deal with destabilisation of cooperation cycles due to periodic defection. The performance of agents endowed with differing emotional characters are again tested under different initial conditions and specific behavioural features of particular emotional characters are considered. In doing this I comment upon how different emotional characters deal with periodic defection and what the best approach is both in context of an agent's individual score and the total score of the system

Exploring a proposed WHO method to determine thresholds for seasonal influenza surveillance

INTRODUCTION Health authorities find thresholds useful to gauge the start and severity of influenza seasons. We explored a method for deriving thresholds proposed in an influenza surveillance manual published by the World Health Organization (WHO). METHODS For 2002-2011, we analysed two routine influenza-like-illness (ILI) datasets, general practice sentinel surveillance and a locum medical service sentinel surveillance, plus laboratory data and hospital admissions for influenza. For each sentinel dataset, we created two composite variables from the product of weekly ILI data and the relevant laboratory data, indicating the proportion of tested specimens that were positive. For all datasets, including the composite datasets, we aligned data on the median week of peak influenza or ILI activity and assigned three threshold levels: seasonal threshold, determined by inspection; and two intensity thresholds termed average and alert thresholds, determined by calculations of means, medians, confidence intervals (CI) and percentiles. From the thresholds, we compared the seasonal onset, end and intensity across all datasets from 2002-2011. Correlation between datasets was assessed using the mean correlation coefficient. RESULTS The median week of peak activity was week 34 for all datasets, except hospital data (week 35). Means and medians were comparable and the 90% upper CIs were similar to the 95(th) percentiles. Comparison of thresholds revealed variations in defining the start of a season but good agreement in describing the end and intensity of influenza seasons, except in hospital admissions data after the pandemic year of 2009. The composite variables improved the agreements between the ILI and other datasets. Datasets were well correlated, with mean correlation coefficients of >0.75 for a range of combinations. CONCLUSIONS Thresholds for influenza surveillance are easily derived from historical surveillance and laboratory data using the approach proposed by WHO. Use of composite variables is helpful for describing influenza season characteristics.The General Practitioner Sentinel Surveillance system is funded by the Victorian Government Department of Health. Ee Laine Tay was supported by a Master of Philosophy in Applied Epidemiology Scholarship funded by the Victorian Infectious Diseases Reference Laboratory and the Victorian Department of Health

Assessing the quality of water quality assessments: an analytical quality control protocol for benthic diatoms

Analytical Quality Control (AQC) is becoming increasingly recognised as anessential guarantee of the quality of environmental data. Techniques forassessing the quality of chemical data and some biological data (such aschlorophyll concentration) are well developed and, conceptually, quitestraightforward. Depending upon the system, either a proportion of thesamples are subjected to independent analysis, or samples with knownconcentrations of a determinand are inserted into routine analytical runs.Matching the "observed" and "expected" values is then a relativelystraightforward statistical exercise

Deriving nutrient criteria to support 'good' ecological status in European lakes: An empirically based approach to linking ecology and management

European water policy has identified eutrophication as a priority issue for water management. Substantial progress has been made in combating eutrophication but open issues remain, including setting reliable and meaningful nutrient criteria supporting ʽgoodʼ ecological status of the Water Framework Directive. The paper introduces a novel methodological approach - a set of four different methods - that can be applied to different ecosystems and stressors to derive empirically-based management targets. The methods include Ranged Major Axis (RMA) regression, multivariate Ordinary Least Squares (OLS) regression, logistic regression, and minimising the mismatch of classifications. We apply these approaches to establish nutrient (nitrogen and phosphorus) criteria for the major productive shallow lake types of Europe: high alkalinity shallow (LCB1; mean depth 3–15 m) and very shallow (LCB2; mean depth