WebAnalyzer: accurate detection of HTTP attack traces in web server logs

This paper presents a tool for detecting attacks against web server, using the analysis of web server log files. The main characteristic of this tool is its accuracy, being able to carefully graduate its analysis according to the actual success of the attacker. This capability is based on the design of a simple yet powerful signature definition language. We demonstrate the accuracy of the tool using a set of log lines representing several attack conditions and attack results.     

Inelastic Neutron Scattering of Hydrogen and Butyronitrile Adsorbed on Raney-Co Catalysts

Inelastic Neutron Scattering (INS) spectroscopy was used to characterize the catalytic hydrogenation of butyronitrile on the surface of parent and LiOH-modified Raney-Co. At low pressure hydrogen is mainly adsorbed on 3-fold sites. Co-adsorbed butyronitrile and hydrogen react on the unmodified Raney-Co sample to several partially hydrogenated products that contain N-H bonds. The nature of the species suggests that bi-molecular condensation leading to N-Butylidene-1-butanamine is feasible.     

Aspartate transcarbamylase from the deep-sea hyperthermophilic archaeon Pyrococcus abyssi: genetic organization, structure, and expression in Escherichia coli

The genes coding for aspartate transcarbamylase (ATCase) in the deep-sea hyperthermophilic archaeon Pyrococcus abyssi were cloned by complementation of a pyrB Escherichia coli mutant. The sequence revealed the existence of a pyrBI operon, coding for a catalytic chain and a regulatory chain, as in Enterobacteriaceae. Comparison of primary sequences of the polypeptides encoded by the pyrB and pyrI genes with those of homologous eubacterial and eukaryotic chains showed a high degree of conservation of the residues which in E. coli ATCase are involved in catalysis and allosteric regulation. The regulatory chain shows more-extensive divergence with respect to that of E. coli and other Enterobacteriaceae than the catalytic chain. Several substitutions suggest the existence in P. abyssi ATCase of additional hydrophobic interactions and ionic bonds which are probably involved in protein stabilization at high temperatures. The catalytic chain presents a secondary structure similar to that of the E. coli enzyme. Modeling of the tridimensional structure of this chain provides a folding close to that of the E. coli protein in spite of several significant differences. Conservation of numerous pairs of residues involved in the interfaces between different chains or subunits in E. coli ATCase suggests that the P. abyssi enzyme has a quaternary structure similar to that of the E. coli enzyme. P. abyssi ATCase expressed in transgenic E. coli cells exhibited reduced cooperativity for aspartate binding and sensitivity to allosteric effectors, as well as a decreased thermostability and barostability, suggesting that in P. abyssi cells this enzyme is further stabilized through its association with other cellular components.     

Optimisation d’un guide d’onde de silicium sur saphir pour l’observation de la bistabilité optique

A silicon on sapphire nonlinear waveguide which can be used for all-optical logic operation is described. A theoretical analysis confirms that the fast switchings experimentally observed using this device result from a competition between electronic and thermal nonlinear effects occurring in silicon. Numerical simulations display the influence of various parameters on the device operation conditions as an optical switch or bistable device.     

Tyrosine phosphorylation of NMDA receptor in rat striatum: effects of 6-OH-dopamine lesions

It is technically demanding to make intracellular measurements of mechanoreception in intact arthropod cuticular receptors. Here we introduce a method for recording mechanically induced electrical events in a class of spider mechanoreceptors using single electrode voltage- or current-clamp. A concave piece of cuticle containing a mechanosensitive lyriform slit organ was dissected free and fixed with wax onto a specially designed holder. This holder-cuticle complex, filled with spider saline, allowed displacement of the slit membrane from below while simultaneously recording intracellularly from neurons of the organ through a thin saline film. Extracellular ion concentrations could be changed and ion channel blockers could be applied to the bath. The method promises to allow the investigation of the ion channels responsible for mechanically transduced receptor signals and spike encoding.     

Cobalt catalysts for the production of alcohols in the F.T. Synthesis

A cobalt catalyst is prepared by reduction of a cobalt salt on cobalt oxide used as a support. The selectivity of the Fischer-Tropsch synthesis is thus changed and the production of alcohols is observed.This paper is dedicated to the late Professor Paul Canesson.     

Effets d’un trou métallisé sur les caractéristiques de rayonnement d’une antenne plaque microruban alimentée par une ligne coaxiale à travers le plan de masse

Effects of the via-hole implementation on radiation characteristics of a microstrip patch antenna are computed on an EM resolver based upon integral equations and numerically solved by moment method. Coaxial feed and via-holes are considered as integral parts of the antenna so that after an accurate modeling of the incident field, induced effects of the holes are naturally accounted for. Results show that for some locations, the via-hole effects on the radiation characteristics are negligeable. Such predictions suggest solutions for various problems of practical interest in industrial applications of this new technology.     

Secretion of growth hormone in hyperthyroidism

The authors studied growth hormone (GH) secretion in a group of adult controls and another group of hyperthyroid patients after stimulation with intravenous insulin-induced (0,1 IU/kg) hypoglycemia, aiming to clear out the problem of discrepancies in literature concerning GH secretion in hyperthyroidism. They concluded that in this syndrome, GH levels are significantly higher than those of controls. The GH releasing response is normal, though it could be expected to be decreased due to decreased pituitary GH contents as a result of permanent somatotrophic cell stimulation.     

Decomposition of linear sequential machines

Linear sequential machines can sometimes be decomposed into parallel and series connections of smaller linear sequential machines. Necessary and sufficient conditions are given for such decompositions to exist for finite linear sequential machines.Research sponsored by the Air Force Office of Scientific Research, Grant AF-AFOSR 639-67, and by the National Science Foundation, Grant GP-6945     

Determination of homopolypeptide conformational changes by the modeling of electrophoretic mobilities

This work deals with the modeling of electrophoretic mobilities of end-charged homopolypeptides. The ionic mobilities of six families of homopolypeptides (polyglycines, poly-L-alanines, poly-L-valines, poly-L-leucines, poly-L-isoleucines, and poly-L-phenylalanines), with polymerization degrees up to 11, have been carefully determined. The electrophoretic frictional coefficients derived from the ionic mobility values were modeled by the hydrodynamic frictional coefficient of an equivalent cylinder. The hydrodynamic modeling allowed the determination of the molecular dimensions of the homopolypeptides in the electrolyte. The results were in good accordance with the expected geometry of the molecules. This approach allows monitoring the change in peptide conformations as a function of the experimental conditions (temperature, nature of the solvent) through the determination of geometrical molecular parameters (total peptide length, lateral radius of the equivalent cylinder, and folding angle). The influence of the bulkiness of the homopolypeptide lateral chain on the conformation is also discussed.