A crossover for the bad configurations of random walk in random scenery

Article / Letter to editorMathematisch Instituu

The post-minig context at Decazeville-Firmi concession (Aveyron, France) : analysis of impacts resulting from the cessation of pumping at the central shaft. Survey of various scenarios related to the water level of the Pit lake in the Grande Decouverte

International audienceWithin the frame of the Survey related to the cessation of mine workings in Decazeville-Firmi concession, various impacts resulting from the cessation of pumping at the Central Shaft were assessed. Mainly these impacts are related to groundwater behaviour in the abandoned underground coalmines, hydrochemistry of waters discharged to the environment, ground stability concerns and coal gas emanations. This analysis allowed the choice of the most appropriate elevation of the pit lake level in the Grande Découverte, with the necessity to continue the pumping. Two main objectives were reached. The elected elevation is high enough to result in a permanent chemical stratification, which allows the pumping of the superficial waters and its discharge to natural watercourses without any treatment. The elected elevation is low enough to avoid any problem of inflow of water or ground stability at some particular places which might have been threatened by the rising of the piezometric level of the mining aquifer. Lastly, the elected elevation of the pit lake allows a quality scenery design around the pit lake.Dans le cadre de la constitution du Dossier d'arrêt des travaux miniers dans la concession de Decazeville-Firmi, différents impacts résultant de l'arrêt du pompage au Puits Central ont été étudiés. Ces impacts sont principalement relatifs au comportement de l'aquifère minier, à la qualité des eaux restituées au milieu naturel, à la stabilité des terrains et aux gaz de mines. Cette étude a conduit à la définition de la meilleure cote du lac minier de Decazeville dans la Grande Découverte, en respectant deux principaux objectifs, avec la nécessité de poursuivre le pompage. La cote retenue est suffisamment élevée pour permettre l'établissement d'une stratification chimique permanente dans le lac minier, ce qui rend possible le pompage par soutirage de la tranche d'eau superficielle du lac et sa restitution au milieu naturel sans traitement particulier. La cote est suffisamment basse pour éviter tout problème de venue d'eau ou de stabilité des terrains en quelques zones particulières qui auraient pu être menacées par la remontée du niveau piézométrique de l'aquifère minier. Enfin, la cote retenue permet de réaliser un aménagement paysager de qualité autour du lac minier

Treatment of metal-laden hazardous wastes with advanced clean coal technology by-products. Quarterly report, June 30--September 30, 1996

During the fourth quarter of Phase 2, work continued on evaluating treatment of the seventh residue of Phase 1, conducting scholarly work, preparing for field work, preparing and delivering presentations, and making additional outside contacts. The work consisted of further testing of the solidification of the seventh hazardous waste--the sandblast residue from paint removal in a building--and examining the microstructure of the products of solidification. There were two treated waste mixtures which demonstrated immediate stabilization, the sandblast residue w/30% spray drier residue (CONSOL) and the sandblast residue w/50% PFBC residue (Tidd)

Treatment of metal-laden hazardous wastes with advanced clean coal technology by-products. Quarterly report, March 30, 1996--June 30, 1996

Progress is described on the use of by-products form clean coal technologies for the treatment of hazardous wastes. During the third quarter of Phase 2, work continued on evaluating Phase 1 samples (including evaluation of a seventh waste), conducting scholarly work, preparing for field work, preparing and delivering presentations, and making additional outside contacts

Identification of the N-terminal Peptide Binding Site of Glucose-regulated Protein 94

Because the stress protein GRP94 can augment presentation of peptides to T cells, it is important to define how it, as well as all other HSP90 family members, binds peptides. Having previously shown that the N-terminal half of GRP94 can account for the peptide binding activity of the full-length protein, we now locate this binding site by testing predictions of a molecular docking model. The best predicted site was on the opposite face of the β sheet from the pan-HSP90 radicicol-binding pocket, in close proximity to a deep hydrophobic pocket. The peptide and radicicol-binding sites are distinct, as shown by the ability of a radicicol-refractive mutant to bind peptide. When the fluorophore acrylodan is attached to Cys(117)within the hydrophobic pocket, its fluorescence is reduced upon peptide binding, consistent with proximity of the two ligands. Substitution of His(125), which contacts the bound peptide, compromises peptide-binding activity. We conclude that peptide binds to the concave face of the β sheet of the N-terminal domain, where binding is regulated during the action cycle of the chaperone

High Humidity Leads to Loss of Infectious Influenza Virus from Simulated Coughs

Background The role of relative humidity in the aerosol transmission of influenza was examined in a simulated examination room containing coughing and breathing manikins. Methods Nebulized influenza was coughed into the examination room and Bioaerosol samplers collected size-fractionated aerosols (\u3c1 µM, 1–4 µM, and \u3e4 µM aerodynamic diameters) adjacent to the breathing manikin’s mouth and also at other locations within the room. At constant temperature, the RH was varied from 7–73% and infectivity was assessed by the viral plaque assay. Results Total virus collected for 60 minutes retained 70.6–77.3% infectivity at relative humidity ≤23% but only 14.6–22.2% at relative humidity ≥43%. Analysis of the individual aerosol fractions showed a similar loss in infectivity among the fractions. Time interval analysis showed that most of the loss in infectivity within each aerosol fraction occurred 0–15 minutes after coughing. Thereafter, losses in infectivity continued up to 5 hours after coughing, however, the rate of decline at 45% relative humidity was not statistically different than that at 20% regardless of the aerosol fraction analyzed. Conclusion At low relative humidity, influenza retains maximal infectivity and inactivation of the virus at higher relative humidity occurs rapidly after coughing. Although virus carried on aerosol particles \u3c4 µM have the potential for remaining suspended in air currents longer and traveling further distances than those on larger particles, their rapid inactivation at high humidity tempers this concern. Maintaining indoor relative humidity \u3e40% will significantly reduce the infectivity of aerosolized virus

Human airway construct model is suitable for studying transcriptome changes associated with indoor air particulate matter toxicity

In vitro models mimicking the human respiratory system are essential when investigating the toxicological effects of inhaled indoor air particulate matter (PM). We present a pulmonary cell culture model for studying indoor air PM toxicity. We exposed normal human bronchial epithelial cells, grown on semi‐permeable cell culture membranes, to four doses of indoor air PM in the air‐liquid interface. We analyzed the chemokine interleukin‐8 concentration from the cell culture medium, protein concentration from the apical wash, measured tissue electrical resistance, and imaged airway constructs using light and transmission electron microscopy. We sequenced RNA using a targeted RNA toxicology panel for 386 genes associated with toxicological responses. PM was collected from a non‐complaint residential environment over 1 week. Sample collection was concomitant with monitoring size‐segregated PM counts and determination of microbial levels and diversity. PM exposure was not acutely toxic for the cells, and we observed up‐regulation of 34 genes and down‐regulation of 17 genes when compared to blank sampler control exposure. The five most up‐regulated genes were related to immunotoxicity. Despite indications of incomplete cell differentiation, this model enabled the comparison of a toxicological transcriptome associated with indoor air PM exposure

Small Left Atrium: An Adjunctive Sign of Hemodynamically Compromised Massive Pulmonary Embolism

Pulmonary embolism (PE) is a common disease with a high mortality rate due to right ventricular dysfunction and underfilling of the left ventricle. We present a case of a 33-year-old man with hemodynamically compromised massive PE. His left atrium was collapsed with marked dilatation of the right atrium and ventricle on multi-detector-row CT scans. The patient was treated with an intracatheter injection of a mutant tissue-type plasminogen activator and subsequently showed clinical and radiological improvements. The small left atrial size in combination with a right ventricular pressure overload was considered to be an adjunctive sign of hemodynamically compromised massive PE