Representing moving objects in computer-based expert systems: the overtake event example

Qualitative formalisms suited to express qualitative temporal or spatial relationships between entities, have gained wide acceptance as a useful way of abstracting from the real world. The question remains how to describe spatio-temporal concepts, such as the interaction between moving objects, adequately within a qualitative calculus and more specifically how to use this in expert systems. With this in mind, the Qualitative Trajectory Calculus (QTC) has been introduced. QTC enables comparisons between positions of objects at different time points to be made. By reducing the continuum to the qualitative values −, 0 and +, continuous movements can be described qualitatively. To illustrate the naturalness of QTC, the overtake event is studied. An overtake event is a typical example of objects moving in a particular domain and can become important, for example in the study of traffic engineering. A so-called conceptual animation is represented, being a sequence of QTC-relations, following the constraints imposed by qualitative reasoning. It is shown that different kinds of behaviour having certain common characteristics are reflected by the structure (e.g. symmetrical aspects) of the conceptual animations.     

Influence of κ-carrageenan on the thermal gelation of salt-soluble meat proteins

Cooked ham-based model systems were prepared using salt-soluble meat protein isolate, κ-carrageenan and sodium and potassium chloride. The pH was set to 6.2 using a 50mM PIPES-buffer. An experimental mixture design was used to study the effect of carrageenan on the structure build-up of the gelled meat products. In situ gelation experiments were carried out on a controlled-stress rheometer, while a texture analyzer was used to determine the large deformation behaviour. The water holding capacity was measured by a centrifugal technique and confocal scanning laser microscopy was used to visualize the microstructure of the gelled meat products. κ-Carrageenan was found to increase the complex modulus, the gel strength and the water holding capacity, although these properties were mainly governed by the concentration of meat protein isolate.     

Is biological treatment a viable alternative for micropollutant removal in drinking water treatment processes?

In western societies, clean and safe drinking water is often taken for granted, but there are threats to drinking water resources that should not be underestimated. Contamination of drinking water sources by anthropogenic chemicals is one threat that is particularly widespread in industrialized nations. Recently, a significant amount of attention has been given to the occurrence of micropollutants in the urban water cycle. Micropollutants are bioactive and/or persistent chemicals originating from diverse sources that are frequently detected in water resources in the pg/L to μg/L range. The aim of this review is to critically evaluate the viability of biological treatment processes as a means to remove micropollutants from drinking water resources. We first place the micropollutant problem in context by providing a comprehensive summary of the reported occurrence of micropollutants in raw water used directly for drinking water production and in finished drinking water. We then present a critical discussion on conventional and advanced drinking water treatment processes and their contribution to micropollutant removal. Finally, we propose biological treatment and bioaugmentation as a potential targeted, cost-effective, and sustainable alternative to existing processes while critically examining the technical limitations and scientific challenges that need to be addressed prior to implementation. This review will serve as a valuable source of data and literature for water utilities, water researchers, policy makers, and environmental consultants. Meanwhile this review will open the door to meaningful discussion on the feasibility and application of biological treatment and bioaugmentation in drinking water treatment processes to protect the public from exposure to micropollutants.     

Chemical and biological technologies for hydrogen sulfide emission control in sewer systems: a review

Biogenic corrosion of sewers represents a cost of about 10% of total sewage treatment cost in Flanders (Belgium) and is further increasing. In the past, research has resulted in a number of prevention methods, such as injection of air, oxygen, H(2)O(2), NaClO, FeCl(3) and FeSO(4). The possibility of biological oxidation of sulfide using nitrate as the electron acceptor has also been explored in sewer systems. However, all of these methods have a problem with the high cost (euro 1.9-7.2 kg(-1)S removal). In this review, new approaches for hydrogen sulfide emission control in sewer systems are discussed. The control of hydrogen sulfide emission by using a microbial fuel cell (MFC) can be cost-effective while the BOD is removed partially. The use of phages that target sulfate-reducing bacteria (SRB) can possibly inhibit sulfide formation. Novel inhibitors, such as slow release solid-phase oxygen (MgO(2)/CaO(2)) and formaldehyde, warrant further study to control hydrogen sulfide emission in sewer systems.     

Attraction Pheromone of The Benthic Diatom <Emphasis Type="Italic">Seminavis robusta</Emphasis>: Studies on Structure-Activity Relationships

Recently the first pheromone of a marine diatom was identified to be the diketopiperazine (S,S)-diproline. This compound facilitates attraction between mating partners in the benthic diatom Seminavis robusta. Interestingly, sexualized S. robusta cells are attracted to both the natural pheromone (S,S)-diproline as well as to its enantiomer (R,R)-diproline. Usually stereospecificity is a prerequisite for successful substrate-receptor interactions, and especially pheromone perception is often highly enantioselective. Here we introduce a structure-activity relationship study, to learn more about the principles of pheromone reception in diatoms. We analyzed the activity of nine different diketopiperazines in attraction and interference assays. The pheromone diproline itself, as well as a pipecolic acid derived diketopiperazine with two expanded aliphatic ring systems, showed the highest attractivity. Hydroxylatoin of the aliphatic rings abolished any bioactivity. Diketopiperazines derived from acyclic amino acids were not attrative as well. All stereoisomers of both the diproline and the pipecolic acid derived diketopiperazine were purified by enantioselective high-performance liquid chromatography, and application in bioactivity tests confirmed that attraction pheromone perception in this diatom is indeed not stereospecific. However, the lack of activity of diketopiperazines derived from acyclic amino acids suggests a specificity that prevents misguidance to sources of other naturally occurring diketopiperazines.     

GABAA Receptor Autoantibodies Decrease GABAergic Synaptic Transmission in the Hippocampal CA3 Network

Autoimmune encephalitis associated with antibodies (Abs) against α1, β3, and γ2 subunits of γ-aminobutyric acid receptor A (GABA_AR) represents a severe form of encephalitis with refractory seizures and status epilepticus. Reduction in inhibitory GABAergic synaptic activity is linked to dysfunction of neuronal networks, hyperexcitability, and seizures. The aim in this study was to investigate the direct pathogenic effect of a recombinant GABA_AR autoantibody (rAb-IP2), derived from the cerebrospinal fluid (CSF) of a patient with autoimmune GABA_AR encephalitis, on hippocampal CA1 and CA3 networks. Acute brain slices from C57BL/6 mice were incubated with rAb-IP2. The spontaneous synaptic GABAergic transmission was measured using electrophysiological recordings in voltage-clamp mode. The GABA_AR autoantibody rAb-IP2 reduced inhibitory postsynaptic signaling in the hippocampal CA1 pyramidal neurons with regard to the number of spontaneous inhibitory postsynaptic currents (sIPSCs) but did not affect their amplitude. In the hippocampal CA3 network, decreased number and amplitude of sIPSCs were detected, leading to decreased GABAergic synaptic transmission. Immunohistochemical staining confirmed the rAb-IP2 bound to hippocampal tissue. These findings suggest that GABA_AR autoantibodies exert direct functional effects on both hippocampal CA1 and CA3 pyramidal neurons and play a crucial role in seizure generation in GABA_AR autoimmune encephalitis.     

A general-purpose signal processor architecture for neurocomputing and preprocessing applications

A general-purpose Neural Signal Processor MA16 is presented the architecure of which is guided by an analysis of today's neural algorithms. The MA16 executes the elementary algorithmic strings which are compute-bound and shared by all neural nets; operations which are not time consuming are let to hardware off-the-shelf. Digital design is chosen because of flexibility and computation accuracy. The throughput is 800 million connections per second at a clock frequency of 50 MHz (1 connection = 16 bit). This performance is valid for arbitrary networks provided they consist of more than 16 neurons each comprising more than 16 synapses. Depending on the needs of the application under consideration a linear or 2-dimensional array of VLSI chips can be constructed in order to provide sufficient processing power and weight memory.     

Optimal economic policies and uncertainty: The case against policy selection by nonlinear programming

Full optimal stochastic control is not generally a feasible decision technique in economics because of the dimensionality and nonlinearity of the integrations involved, and because of the inseparability of the deterministic and stochastic components of the decision variables. Nevertheless, despite some suboptimality due to linearisation errors, the effects of uncertainty can be controlled by repeated linearisations of the system. An example of Dutch economic planning clearly shows the advantages of this approach for selecting economic policies.     

A novel approach to ion separations in solution: synchronized cyclic capillary electrophoresis (SCCE)

A novel concept for ion separation is presented. Repeated column switching in capillary electrophoresis allows for the elimination of unwanted sample components, and for the separation of species having very similar mobilities. Theoretical considerations predict good separation efficiencies, e.g., high plate numbers per volt. Using micromachining techniques, a planar glass structure has been fabricated, composed of four capillaries of 20 mm length arranged in a square. Laser fluorescence detection is used in the detection scheme. To move a component around one cycle, 1 min is needed when applying 2.5 kV. A demonstration of the peak band broadening after several cycles and a separation example are given.