Addition of trace metals increases denitrification rate in closed marine systems

We investigated the effect of trace metals (Fe, Mn, Cu, Zn and Mo) on the denitrification unit at the Montreal Biodome. Two dosages of the five trace metals were tested on a denitrifying bacterial population which was extracted from the denitrification unit and cultured in 250 mL chemostats with artificial seawater. The low dosage showed a 20% increase in the denitrification rate whereas the high dosage had a more pronounced effect with a 250% increase. No increase in bacterial growth was observed, suggesting that the trace metals had an effect on the denitrification activity. When the trace metals were tested separately, only iron had a significant effect similar to the increase in the denitrification rate observed when the five trace metals were added. The combination of Fe and Mn caused a small but significant increase compared to the five trace metals. We then tested the effect of adding Fe, Mn and Cu to the denitrification unit at the Montreal Biodome. A high dosage of these trace metals showed a 250% increase in the denitrification rate, which went from 200 to 700 g NO(x)-N/d. Our results showed that the addition of trace metals is crucial for denitrification activities.     

Global warming and thermohaline circulation stability

The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future.     

The advance of technology and the scientific commons

The advance of technology proceeds through an evolutionary process, with many different new departures in competition with each other and with prevailing practice, and with ex-post selection determining the winners and losers. In modern times what gives power to the process is the strong base of scientific and technological understanding and technique that guides the efforts of those seeking to advance the technology. Most of that base is part of a commons open to all who have expertise in a field. The proprietary aspects of technology traditionally have comprised a small topping on the commons. But recently parts of the commons have become privatized. While the justification for the policies and actions that have spurred privatization of the commons is that this will spur technological progress, the argument here is that the result can be just the opposite.     

The cumulative advance of human know-how

Modern humans possess an enormous amount of 'know-how' that enables them to do things that early humans could not dream of doing. This paper explores some promising connections between two bodies of empirical research and theorizing that bear on technological know-how and its advance. Cognitive science is concerned with the nature and mechanisms of human knowing. The focus traditionally has not been on the knowledge involved in complex technologies, nor on the processes through which human know-how has advanced over time. However, certain recent developments in this field provide a nice linkage with the implicit cognitive theorizing used by scholars who study the advance of technology. And a number of the debates in the two fields are similar.     

New neural circuits for robot phonotaxis

W. Grey Walter built robotic systems to improve understanding of biological systems. In that tradition, this paper reports ongoing work on a robot model of cricket sound localization. The main advances are the inclusion of a much larger range of neuroethological detail, and the investigation of multimodal influences on the behaviour. The former allows exploration of the functionality of identified neurons in the insect, including the possible roles of multiple sensory fibres, mutually inhibitory connections, and brain neurons with pattern-filtering properties. The latter focuses on the inclusion of an optomotor stabilization response, and how this might improve tracking, particularly under conditions of random disturbance.     

Performance Measurement in the Belgian Document Ordering and Delivery System Impala

This paper deals with performance measures and performance indicators in the Impala electronic document ordering and delivery system for research libraries in Belgium and compares these with some international standards as, e.g., the ProLib/PI study commissioned by the European Commission.Performance measures: Costs (clearinghouse principle) Number of ILL requests made to other libraries Number of ILL requests made to other libraries without success Number of ILL requests made to other libraries with success Number of ILL requests received from other libraries Number of ILL requests received from other libraries and not satisfied Number of ILL requests received from other libraries that were satisfied Frequency asked titlesPerformance indicators: Success rate Borrowing-lending ratio per library Response times, split into several segments of the ILL-procedureThe article concludes with some indications for quality measurement in electronic document delivery where Impala will be able to measure the real supply times as perceived by the end user.     

Process control in CNC manufacturing for discrete components: A STEP-NC compliant framework

With today's highly competitive global manufacturing marketplace, the pressure for right-first-time manufacture has never been so high. New emerging data standards combined with machine data collection methods, such as in-process verification lead the way to a complete paradigm shift from the traditional manufacturing and inspection to intelligent networked process control. Low-level G and M codes offer very limited information on machine capabilities or work piece characteristics which consequently, results in no information being available on manufacturing processes, inspection plans and work piece attributes in terms of tolerances, etc. and design features to computer numerically controlled (CNC) machines. One solution to the aforementioned problems is using STEP-NC (ISO 14649) suite of standards, which aim to provide higher-level information for process control. In this paper, the authors provide a definition for process control in CNC manufacturing and identify the challenges in achieving process control in current CNC manufacturing scenario. The paper then introduces a STEP-compliant framework that makes use of self-learning algorithms that enable the manufacturing system to learn from previous data and results in eliminating the errors and consistently producing quality products. The framework relies on knowledge discovery methods such as data mining encapsulated in a process analyser to derive rules for corrective measures to control the manufacturing process. The design for the knowledge-based process analyser and the various process control mechanisms conclude the paper.     

On the role of the Facilitator in information security risk assessment

In organisations where information security has historically been a part of management and for which the risk assessment methodologies have been designed there are established methods for communicating risk. This is the case for example in the banking and military sectors. However in organisations where information security is not embedded into management thinking and where the relationship between information security and the business is less clear-cut, communicating the risks to the business is less straightforward. In such circumstances it has been observed during field research that information security risk assessments frequently output findings to which the business cannot relate and the process is consequently often viewed as a “tick box” exercise, as opposed to one that provides real value to the business. In such a situation the information security risk assessment is divorced from the business process and not embedded into the organisation’s processes or thinking. The research for this paper was undertaken in order to identify what needs to be done in order to ensure that businesses of this type find the risk assessment process valuable in practice. Lizzie Coles-Kemp is a postgraduate research student in Computer Science and Richard E. Overill is a Senior Lecturer in Computer Science.     

Modified multi-layered perceptron applied to packing and covering problems

Prior knowledge of the input–output problems often leads to supervised learning restrictions that can hamper the multi-layered perceptron’s (MLP) capacity to find an optimal solution. Restrictions such as fixing weights and modifying input variables may influence the potential convergence of the back-propagation algorithm. This paper will show mathematically how to handle such constraints in order to obtain a modified version of the traditional MLP capable of solving targeted problems. More specifically, it will be shown that fixing particular weights according to prior information as well as transforming incoming inputs can enable the user to limit the MLP search to a desired type of solution. The ensuing modifications pertaining to the learning algorithm will be established. Moreover, four supervised improvements will offer insight on how to control the convergence of the weights towards an optimal solution. Finally, applications involving packing and covering problems will be used to illustrate the potential and performance of this modified MLP.     

The meaning of silence

Silence resides in the gaps between the known islands of explicit knowledge. Rather than expecting to build systems with complete information, we take a human-centred approach. Individual citizens need to be active, engage in dialogue and be aware of the importance of tacit knowledge. As societies, we recognise the incompleteness and inconsistency of our discourse.