Dynkin games in a general framework

We revisit the Dynkin game problem in a general framework, improve classical results and relax some assumptions. The criterion is expressed in terms of families of random variables indexed by stopping times. We construct two nonnegative supermartingales families $J$ and $J'$ whose finitness is equivalent to the Mokobodski's condition. Under some weak right-regularity assumption, the game is shown to be fair and $J-J'$ is shown to be the common value function. Existence of saddle points is derived under some weak additional assumptions. All the results are written in terms of random variables and are proven by using only classical results of probability theory.Comment: stochastics, Published online: 10 Apr 201

Stevia : A True Glycoside Used as a Sweetener and Not Affecting Behavior

Using ants as models, the glycoside rebaudioside A, a sweetener extracted from the plant Stevia rebaudiana and commercialized under the name ‘stevia’, was shown to have no effect on their food consumption, locomotion, precision of reaction, response to pheromones, brood caring, cognition, visual and olfactory conditioning and memory, although this sweetener slightly increased the ants audacity. However, when having the choice between stevia and saccharose, the ants somewhat preferred the latter. Stevia is thus a safe sweetener which does not impact general health, behavior and cognition, but it is generally perceived less pleasant than saccharose

Physiological and Ethological Disruptions Induced by a Mixture of Saccharose/Sucralose 99.5/0.5 - A Study on Ants as Models

Experiments made on ants as biological models revealed that a saccharose/sucralose 95.5/.05 mixture increased sugar water consumption, decreased general activity, precision of reaction, audacity, brood caring, cognition and ability in acquiring visual conditioning (short term memory), induced aggressiveness against nestmates, and slightly reduced tactile perception. It may not change the speed of locomotion and did not affect middle and long term memory. The adverse effects may be related to the strong sugared taste of the mixture (in presence of sugar and the saccharose/sucralose mixture, the ants slightly preferred the mixture) though it contains little sugar, and to the toxic chloropropanols sucralose may produce. When ants consumed again sugar instead of a saccharose/sucralose mixture, their aggressiveness rapidly decreased during eight hours and entirely vanished in 29 hours

Dynkin games in a general framework

We revisit the Dynkin game problem in a general framework and relax some assumptions. The payoffs and the criterion are expressed in terms of families of random variables indexed by stopping times. We construct two nonnegative supermartingales families $J$ and $J'$ whose finitness is equivalent to the Mokobodski's condition. Under some weak right-regularity assumption on the payoff families, the game is shown to be fair and $J-J'$ is shown to be the common value function. Existence of saddle points is derived under some weak additional assumptions. All the results are written in terms of random variables and are proven by using only classical results of probability theory

Antibacterial properties of sophorolipid-modified gold surfaces against Gram positive and Gram negative pathogens.

International audienceSophorolipids are bioderived glycolipids displaying interesting antimicrobial properties. We show that they can be used to develop biocidal monolayers against Listeria ivanovii, a Gram-positive bacterium. The present work points out the dependence between the surface density and the antibacterial activity of grafted sophorolipids. It also emphasizes the broad spectrum of activity of these coatings, demonstrating their potential against both Gram-positive strains (Enteroccocus faecalis, Staphylococcus epidermidis, Streptococcus pyogenes) and Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhymurium). After exposure to sophorolipids grafted onto gold, all these bacterial strains show a significant reduction in viability resulting from membrane damage as evidenced by fluorescent labelling and SEM-FEG analysis

Characterization and catalytic performances of biochars synthesized from a hyperaccumulator plant: Alyssum murale

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Faint Infrared Flares from the Microquasar GRS 1915+105

We present simultaneous infrared and X-ray observations of the Galactic microquasar GRS 1915+105 using the Palomar 5-m telescope and Rossi X-ray Timing Explorer on July 10, 1998 UT. Over the course of 5 hours, we observed 6 faint infrared (IR) flares with peak amplitudes of $\sim 0.3-0.6$ mJy and durations of $\sim 500-600$ seconds. These flares are associated with X-ray soft-dip/soft-flare cycles, as opposed to the brighter IR flares associated with X-ray hard-dip/soft-flare cycles seen in August 1997 by Eikenberry et al. (1998). Interestingly, the IR flares begin {\it before} the X-ray oscillations, implying an ``outside-in'' origin of the IR/X-ray cycle. We also show that the quasi-steady IR excess in August 1997 is due to the pile-up of similar faint flares. We discuss the implications of this flaring behavior for understanding jet formation in microquasars.Comment: 10 pages, 4 figures Accepted for publication in ApJ Letter