Satellite-derived parameters for biological modelling in coastal waters: Illustration over the eastern continental shelf of the Bay of Biscay

In biological modelling of the coastal phytoplankton dynamics, the light attenuation coefficient is often expressed as a function of the concentrations of chlorophyll and mineral suspended particulate matter (SPM). In order to estimate the relationship between these parameters over the continental shelf of the northern Bay of Biscay, a set of in situ data has been gathered for the period 1998-2003 when SeaWiFS imagery is available. These data comprise surface measurements of the concentrations of total SPM, chlorophyll, and irradiance profiles from which is derived the attenuation coefficient of the photosynthetically available radiation, K_PAR. The performance of the IFREMER look-up table used to retrieve the chlorophyll concentration from the SeaWiFS radiance is evaluated on this new set of data. The quality of the estimated chlorophyll concentration is assessed from a comparison of the variograms of the in situ and satellite-derived chlorophyll concentrations. Once the chlorophyll concentration is determined, the non living SPM, which is defined as the SPM not related to the dead or alive endogenous phytoplankton, is estimated from the radiance at 555 nm by inverting a semi-analytic model. This method provides realistic estimations of concentrations of chlorophyll and SPM over the continental shelf all over the year. Finally, a relationship, based on non living SPM and chlorophyll, is proposed to estimate K_PAR on the continental shelf of the Bay of Biscay. The same formula is applied to non living SPM and chlorophyll concentrations, observed in situ or derived from SeaWiFS radiance.     

A Cost-Regular Based Hybrid Column Generation Approach

Constraint Programming (CP) offers a rich modeling language of constraints embedding efficient algorithms to handle complex and heterogeneous combinatorial problems. To solve hard combinatorial optimization problems using CP alone or hybrid CP-ILP decomposition methods, costs also have to be taken into account within the propagation process. Optimization constraints, with their cost-based filtering algorithms, aim to apply inference based on optimality rather than feasibility. This paper introduces a new optimization constraint, cost-regular. Its filtering algorithm is based on the computation of shortest and longest paths in a layered directed graph. The support information is also used to guide the search for solutions. We believe this constraint to be particularly useful in modeling and solving Column Generation subproblems and evaluate its behaviour on complex Employee Timetabling Problems through a flexible CP-based column generation approach. Computational results on generated benchmark sets and on a complex real-world instance are given.A preliminary version of this paper appeared as [7]. This research was supported by the Mathematics of Information Technology and Complex Systems (MITACS) Internship program in association with Omega Optimisation Inc. (CA).     

The ability of non-ergonomists in the health care setting to make manual handling risk assessments and implement changes

The health care setting presents particular risks from manual handling and it is known that training in manual handling techniques is ineffective in reducing these risks when used as a stand-alone measure. The 'Manual Handling Operations Regulations 1992' requires employers to consider hazardous manual handling, advising the use of an ergonomics approach. However, it is not known how well-equipped non-ergonomists in the health care setting are to deal with this approach. Therefore, the ability of non-ergonomists to make manual handling risk assessments, with or without additional training, and to implement changes to the work environment was investigated. Twenty-five pairs of subjects from a broad cross section of departments in a busy teaching hospital were studied; training and a guide book were provided for one of each pair and the guide book only for the other. Subjects then independently prioritised three tasks in their department and undertook a full assessment of a specified task. All work was repeated by an ergonomist and the subjects' assessments were scored in comparison with the ergonomist. Each department was followed up after six months to assess progress with implementing recommendations. Trends in the data indicated that both groups appeared able to identify hazards though not necessarily to prioritise the tasks. The trained group tended to score better in assessments although wide variation existed within both groups and inter-group differences were not significant at the 5% level. Approximately half of staff assessments were considered 'adequate' to 'very good', in comparison with the ergonomist. Implementation of assessment recommendations ranged from nil to almost full compliance. Incomplete implementation seemed to be related to an apparent confusion in some departments over who was responsible for making changes, a lack of finances for changes and overstretched managers having other priorities.     

Cholesterol, endothelial function and cardiovascular disease

Poster presentations have proved to be a popular method of displaying information at conferences, and are being used increasingly as a teaching method. Innovative strategies for teaching and assessing research need to facilitate students' achievement of research skills required for practice. These are outlined by the Department of Health, and emphasize the development of research literacy. Using the poster presentation as a teaching and assessing strategy on diploma level courses (Project 2000 and ENB 870 introduction to the Understanding and Application of Research) has proved to be valuable in developing vital research awareness skills and in harnessing enthusiasm for research. Students imply a sense of achievement gained through the process of developing the poster and the production of the poster itself. Herein lies the value of the poster presentation, for it allows the development of crucial research literacy skills which can be widely used in professional practice and future professional education.     

Tight LP bounds for resource constrained project scheduling

The best lower bound for the Resource Constrained Project Scheduling Problem is currently based on the resolution of several large Linear Programs (Brucker & Knust, EJOR, 107: 272-288, 1998). In this paper, we show that (1) intensive constraint propagation can be used to tighten the initial formulation of the linear programs and (2) we introduce several sets of valid cutting planes. These improvements allow us to close 16 new instances of the PSPLIB with 60 activities and to improve the best known lower bounds of 64 instances.Correspondence to:Philippe BaptisteThe authors would like to thank Peter Brucker and Sigrid Knust for providing their source code as well as Christian Artigues, Jacques Carlier and Philippe Michelon for enlightening discussions on project scheduling.     

Diffusional fluorescence quenching of aromatic hydrocarbons

The quenching of the fluorescence of five aromatic hydrocarbons by three halogenated organics and by molecular oxygen has been measured. Both fluorescence intensity and fluorescence lifetime measurements have been employed to validate results and interpretation; linear Stern-Volmer analyses are shown to apply throughout. The fluorescence quenching rate constant of molecular oxygen for the five aromatic hydrocarbons is essentially equivalent to the diffusion rate constant independent of the fluorophore excitation energy. The halogenated organic-fluorophore rate constants vary by a factor of 965 and are shown to correlate roughly with the energy difference between the quencher and fluorophore excited electronic states in accord with a standard model of quantum two-level mixing. The value of the coupling interaction energy is approximately 2500 cm(-1).     

High pass filter with above IC integrated SrTiO3 high K MIM capacitors

This paper describes realization and characterization of SrTiO₃ (STO) high K MIM capacitors above BiCMOS integrated circuit (IC). These capacitances are connected to IC and are used as coupling capacitors in order to realize a high pass filter. Surface capacitance achieved is 10 nF/mm² with capacitance value of 1.2 nF. The process for STO MIM fabrication does not exceed 400 °C, which is compatible with interconnections. Typical K and dielectric losses values obtained are, respectively 110% and 2%. Yield obtained reaches 83% for capacitors. A functional high pass filter using these STO capacitors was realized in this study. It exhibits a cut-off frequency at 6.5 kHz and a constant gain at higher frequencies of −1.3 dB.     

Optimization of LED‐based light blendings for object presentation

This study looks at the perceived quality of light‐emitting diode (LED)‐based lighting of various colors. The objective was to find out whether LEDs could provide better (i.e., more relevant and acceptable) lighting than that which is obtained with standard halogen or fluorescent sources. The perception of objects was assessed under different lighting schemes. Subjects were invited to add red, cyan and/or amber to white LED‐based light to match the halogen and fluorescence rendering on specific targets: a color chart and a painting. They were also asked to rate the difference between the two, and to express their preference. The results obtained for the perception of LED‐based lighting were quite positive. Color blendings of LED light were found to provide illuminated situations similar to halogens or fluorescent sources. These blendings were well accepted, and indeed often preferred, although the color rendering index (CRI) was always low. This indicates that the CRI as it stands is inadequate to characterize the color rendering of solid‐state light sources, and needs to be updated. LED‐based lighting systems seem to have considerable potential for use in shops and display units, where they may well outperform existing lighting systems. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 310–320, 2009