Phylogeny of trichomonads based on partial sequences of large subunit rRNA and on cladistic analysis of morphological data

Several domains of large subunit rRNA from nine trichomonad species have been sequenced. Molecular phylogenies obtained with parsimony and distance methods demonstrate the trichomonads are a monophyletic group which branches very early in the eukaryotic tree. The topology of the trees is in general agreement with traditional views on evolutionary and systematic relationships of trichomonads. A clear dichotomy is noted between the subfamily Trichomonadinae and the subfamily Tritrichomonadinae. In the latter subfamily, a second division separates the "Tritrichomonas muris-type" species from the "Tritrichomonas augusta-type" ones. Previous evolutionary schemes in which the Monocercomonadidae were regarded as the most "primitive" and the Trichomonadidae as more "evolved" are not in agreement with our molecular data. The emergence of Monocercomonas and Hypotrichomonas at the base of the Tritrichomonas lineage suggests a secondary loss of some cytoskeletal structures, the costa and undulating membrane in these genera. This is corroborated by the early branching position of Trichomitus, which possesses a costa and an undulating membrane and has usually been placed among the Trichomonadidae on the basis of cytological characters. A cladistic analysis was applied to the available morphological characters in order to produce a hierarchical grouping of the taxa reflecting their morphological diversity.     

A Novel Surface Reconstruction and Display Method for Cardiac PET Imaging

Positron emission tomography (PET) allows the in vivo assessment of biochemical activity in humans. The newer PET cameras can create several imaging planes, or slices, through an organ inside the body. The interpretation of two-dimensional (2-D) slices of an organ is often difficult for the clinician since he or she has to form a three-dimensional (3-D) mental composite of the structure of interest. We have developed a set of algorithms to reconstruct a functional three-dimensional surface model of the cardiac left ventricle from a set of two-dimensional cross-sectional image slices generated by PET. The theoretical techniques for this reconstruction method are applicable to most organs provided that the appropriate models for the organs are considered. An automatic boundary detection algorithm outlines the surface of the left ventricle from the 2-D images and assigns intensity values to the surface points whose level is proportional to the local activity. A 3-D surface of the intensity levels, with pseudocolor enhancement, is then displayed with the long axis of the heart in a vertical position. Such a display allows the 3-D myocardial tracer uptake to be clearly visualized by the clinician for better diagnosis.     

Flood Risk Management in Flanders: Past Developments and Future Challenges

This paper presents the state of the art of flood risk management in Flanders, a low-lying region in the northern part of Belgium which is vulnerable to flooding. Possible flood hazard sources are not only the many rivers which pass through the Flemish inland, but also the North Sea, which is sensitive to the predicted sea level rise and which can affect large parts of the Flemish coastal area. Due to the expected increase in flood risks in the 21st century, the Flemish government has changed its flood management strategy from a flood control approach to a risk-based approach. Instead of focusing on protection against a certain water level, the objective now is to assure protection against the consequences of a flood, while considering its probability. In the first part, attention is given to the reasoning and functioning of the risk-based approach. Recent improvements to the approach are discussed, as well as the GIS-implementation of the entire model. The functioning of the approach is subsequently demonstrated in two case studies. The second part of the paper discusses future challenges for the flood risk management in Flanders. The driving force behind these challenges is the European Directive on the assessment and management of flood risks, which entered into force in 2007. The Flemish implementation of the directive is discussed and situated in the European landscape. Finally, attention is given to the communication of flood risks to the general public, since the “availability” of flood risk management plans is among the requirements of the EU Floods Directive.     

Complex system reliability modelling with Dynamic Object Oriented Bayesian Networks (DOOBN)

Nowadays, the complex manufacturing processes have to be dynamically modelled and controlled to optimise the diagnosis and the maintenance policies. This article presents a methodology that will help developing Dynamic Object Oriented Bayesian Networks (DOOBNs) to formalise such complex dynamic models. The goal is to have a general reliability evaluation of a manufacturing process, from its implementation to its operating phase. The added value of this formalisation methodology consists in using the a priori knowledge of both the system's functioning and malfunctioning. Networks are built on principles of adaptability and integrate uncertainties on the relationships between causes and effects. Thus, the purpose is to evaluate, in terms of reliability, the impact of several decisions on the maintenance of the system. This methodology has been tested, in an industrial context, to model the reliability of a water (immersion) heater system.     

Orphan gene finding—an exon assembly approach

This paper introduces an algorithm for finding eukaryotic genes. It particularly addresses the problem of orphan genes, that is of genes that cannot, based on homology alone, be connected to any known gene family and to which it is therefore not possible to apply traditional gene finding methods. To the best of our knowledge, this is also the first algorithm that attempts to compare in an exact way two DNA sequences that contain both coding (i.e. exonic) and non-coding (i.e. intronic and, possibly, intergenic) parts. The comparison is performed following an algorithmical model of a gene that is as close as possible to the biological one (we consider in this paper the “one ORF, one gene” problem only). A gene is seen as a set of exons that are pieces of an assembly and are not independent. The algorithm is efficient enough: although the constants are higher than for usual sequence comparison, its time complexity is proportional to the product of the sequences lengths while its space complexity scales linearly with the length of the smallest sequence.     

A parametric insensitive H2 control design approach

H₂ and H_∞ control design methodologies are known to be efficient to deal with multivariable control problems. However, most of them do not take explicitly the parametric uncertainties into account. This paper proposes a low parametric sensitivity H₂ control design method as an alternative to µ‐synthesis or robust H₂ control design. In addition to the standard H₂ criterion, the H₂ norm of the parametric sensitivity function is introduced in order to improve the robustness of the resulting controller. Unfortunately, this problem is a difficult one. Its equivalence to structured feedback H₂ control problem will be shown. The underlying BMI will be solved by making use of an iterative LMI procedure. Two examples will illustrate the interest of the approach. Copyright © 2004 John Wiley & Sons, Ltd.     

Charge reduction experimental investigation of CO2 single-phase flow in a horizontal micro-channel with constant heat flux conditions

The use of carbon dioxide as alternative refrigerant in refrigeration plants and heat pumps has been focused recently. Through the specific properties of CO₂, the use of very compact heat exchangers is relevant and the technology of micro-channel heat exchangers rises as a suitable solution. The experimental investigation of CO₂ flow in a single micro-channel with an inner diameter of 529 μm is planned with an original test section. This test section is initially dedicated for further CO₂ two-phase flow analysis. The local heat transfer coefficients are estimated with micro-thermocouples stuck on the micro-channel wall. The pressure drop is also measured. This paper presents the first results in single-phase pressure drop and heat transfer and exhibits promising coming data in two-phase flow pressure drop and heat transfer for mass velocity between 200 kg/m²/s and 1400 kg/m²/s and working saturation temperature between −10 °C and 5 °C. The results stress on the good accuracy of suitable classical laws to predict pressure drop and heat transfer in single-phase flow in micro-channel.     

Multiplexed-Based Assessment of DNA Damage Response to Chemotherapies Using Cell Imaging Cytometry

The current methods for measuring the DNA damage response (DDR) are relatively labor-intensive and usually based on Western blotting, flow cytometry, and/or confocal immunofluorescence analyses. They require many cells and are often limited to the assessment of a single or few proteins. Here, we used the Celigo^® image cytometer to evaluate the cell response to DNA-damaging agents based on a panel of biomarkers associated with the main DDR signaling pathways. We investigated the cytostatic or/and the cytotoxic effects of these drugs using simultaneous propidium iodide and calcein-AM staining. We also describe new dedicated multiplexed protocols to investigate the qualitative (phosphorylation) or the quantitative changes of eleven DDR markers (H2AX, DNA-PKcs, ATR, ATM, CHK1, CHK2, 53BP1, NBS1, RAD51, P53, P21). The results of our study clearly show the advantage of using this methodology because the multiplexed-based evaluation of these markers can be performed in a single experiment using the standard 384-well plate format. The analyses of multiple DDR markers together with the cell cycle status provide valuable insights into the mechanism of action of investigational drugs that induce DNA damage in a time- and cost-effective manner due to the low amounts of antibodies and reagents required.