56 research outputs found

    Middle East - North Africa and the millennium development goals : implications for German development cooperation

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              Closed-loop controlled combustion is a promising technique to improve the overall performance of internal combustion engines and Diesel engines in particular. In order for this technique to be implemented some form of feedback from the combustion process is required. The feedback signal is processed and from it combustionrelated parameters are computed. These parameters are then fed to a control process which drives a series of outputs (e.g. injection timing in Diesel engines) to control their values. This paper’s focus lies on the processing and computation that is needed on the feedback signal before this is ready to be fed to the control process as well as on the electronics necessary to support it. A number of feedback alternatives are briefly discussed and for one of them, the in-cylinder pressure sensor, the CA50 (crank angle in which the integrated heat release curve reaches its 50% value) and the IMEP (Indicated Mean Effective Pressure) are identified as two potential control variables. The hardware architecture of a system capable of calculating both of them on-line is proposed and necessary feasibility size and speed considerations are made by implementing critical blocks in VHDL targeting a flash-based Actel ProASIC3 automotive-grade FPGA

    'W' mutant forms of the Fms receptor tyrosine kinase act in a dominant manner to suppress CSF-1 dependent cellular transformation

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    Point mutations in highly conserved amino acid residues in the catalytic domain of the Kit receptor tyrosine kinase (RTK) are responsible for the coat color, fertility and hematopoietic defects of mice bearing mutant alleles at the dominant white-spotting (W) locus. The dominant nature of structural Kit mutations suggests that expression of other kinase-defective RTKs might also specifically interfere with signal transduction by normal receptors. To test this possibility, we have investigated the functional consequences of introducing analogous mutations into the RTK encoded by the c-fms proto-oncogene. Both Fms37 (glu582-->lys) and Fms42 (asp776-->asn) mutant proteins, corresponding to the strongly dominant-negative W37 and W42 mutant c-kit alleles, had undetectable in vitro kinase activity and were unable to transform Rat-2 fibroblasts in the presence of exogenous CSF-1. Moreover, expression of Fms37 or Fms42 proteins in Rat-2 cells specifically inhibited anchorage-independent growth mediated by the normal Fms receptor in the presence of exogenous CSF-1 and conferred a dominant loss of Fms-associated PI3-kinase activity on CSF-1 stimulation. Mutant RTKs, bearing point substitutions identical to those present in mild or severe W mutants, may provide a generally applicable strategy for inducing dominant loss of function defects in RTK-mediated signalling pathways

    Product Form Solution for Stochastic Automata Networks with synchronizations

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    We present a class of Stochastic Automata Networks (SAN) which exhibit a product form solution if some generalized flow equations are satisfied. Unlike previous models on SAN with product form solutions, our model allows synchronizations between automata. This class of SAN is a generalization of Jackson's queueing networks and Gelenbe's networks with positive and negative customers . 1 Introduction Stochastic Automata Networks (SAN for short) have been proposed by B. Plateau [10] as a modeling paradigm to allow easy representation and evaluation of parallel systems. It is clearly understood now that SAN are a particular case of a stochastic extension of Process Algebra. Therefore new results in the context on SAN will often be easily translated into other models based on process algebra. The first method associated to Stochastic Automata Networks was a numerical resolution of steady-state distribution of the Markov chain associated to a SAN [11]. It consists of a improvement of the po..
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