New insights into the dust formation of oxygen-rich AGB stars

We observed the AGB stars S Ori, GX Mon and R Cnc with the MIDI instrument at the VLTI. We compared the data to radiative transfer models of the dust shells, where the central stellar intensity profiles were described by dust-free dynamic model atmospheres. We used Al2O3 and warm silicate grains. Our S Ori and R Cnc data could be well described by an Al2O3 dust shell alone, and our GX Mon data by a mix of an Al2O3 and a silicate shell. The best-fit parameters for S Ori and R Cnc included photospheric angular diameters Theta(Phot) of 9.7+/-1.0mas and 12.3+/-1.0mas, optical depths tau(V)(Al2O3) of 1.5+/-0.5 and 1.35+/-0.2, and inner radii R(in) of 1.9+/-0.3R(Phot) and 2.2+/-0.3R(Phot), respectively. Best-fit parameters for GX Mon were Theta(Phot)=8.7+/-1.3mas, tau(V)(Al2O3)=1.9+/-0.6, R(in)(Al2O3)=2.1+/-0.3R(Phot), tau(V)(silicate)=3.2+/-0.5, and R(in)(silicate)=4.6+/-0.2R(Phot). Our model fits constrain the chemical composition and the inner boundary radii of the dust shells, as well as the photospheric angular diameters. Our interferometric results are consistent with Al2O3 grains condensing close to the stellar surface at about 2 stellar radii, co-located with the extended atmosphere and SiO maser emission, and warm silicate grains at larger distances of about 4--5 stellar radii. We verified that the number densities of aluminum can match that of the best-fit Al2O3 dust shell near the inner dust radius in sufficiently extended atmospheres, confirming that Al2O3 grains can be seed particles for the further dust condensation. Together with literature data of the mass-loss rates, our sample is consistent with a hypothesis that stars with low mass-loss rates form primarily dust that preserves the spectral properties of Al2O3, and stars with higher mass-loss rate form dust with properties of warm silicates.Comment: 20 pages, 10 figure

First whole atmosphere night-time seeing measurements at Dome C, Antarctica

We report site testing results obtained in night-time during the polar autumn and winter at Dome C. These results were collected during the first Concordia winterover by A. Agabi. They are based upon seeing and isoplanatic angle monitoring, as well as in-situ balloon measurements 2 of the refractive index structure constant profiles Cn (h). Atmosphere is divided into two regions: (i) a 36 m high surface layer responsible of 87% of the turbulence and (ii) a very stable free atmosphere above with a median seeing of 0.36+-0.19 arcsec at an elevation of h = 30 m. The median seeing measured with a DIMM placed on top of a 8.5 m high tower is 1.3+-0.8 arcsec.Comment: accepted for publication in PASP (oct 2005

Alteration of size perception: serotonin has opposite effects on the aggressiveness of crayfish confronting either a smaller or a larger rival

International audienceWe injected serotonin (5-HT) into adult male crayfish before pairing them with size-matched non-injected competitors, and observed dyadic agonistic interactions. Paradoxically, 5-HT elicited opposite behavioral responses if the injected animal was opposed by a smaller or larger rival: the level of aggressiveness of the injected crayfish was higher when facing a larger rival but lower when facing a smaller rival. Our results indicate that the effects of 5-HT on aggressiveness are dependent on the perception of the relative size difference of the opponent. In both cases, however, 5-HT significantly delayed the decision to retreat. We conclude that 5-HT does not primarily act on aggressiveness but rather on the brain centers that integrate risk assessment and/or decision making, which then modulate the aggressive response. Our findings support a reinterpretation of the role of 5-HT in crustacean agonistic behavior that may be of interest for studies of other animals

Le parcours de Th. Lalanne : du recueil de données (1947-1952) aux cartes synthétiques de l’Atlas linguistique de la Gascogne maritime

L’Atlas linguistique et ethnographique de la Gascogne (ALG), entreprise du Nouvel Atlas linguistique de la France par régions — initialement sous la direction d’Albert Dauzat — a été élaboré entre 1950 et 1973. Dès les années 1950, Th. Lalanne (l’abbé Lalanne), a été pour le domaine gascon aquitanique le principal enquêteur de l’ALG, pour les volumes 1, 2, 3 d’une enquête reposant sur la méthode directe de transcription sur carnets (49 carnets). Il avait ensuite dressé un petit Atlas linguistique de la Gascogne maritime qui est composé de trois carnets de cartes analytiques et synthétiques ou cumulatives, aujourd’hui numérisé. Th. Lalanne, par le biais d’opérations de décompte élémentaire des oppositions phonétiques, phonologiques, morphologiques, syntaxiques et prosodiques, et après visualisation cartographique du partitionnement de ce territoire, en est arrivé à formuler l’hypothèse, généralisable aux organisations dialectales, d’un ordre par sous-ensembles graduels, c’est-à-dire flous ; ce que, vingt ans plus tard, avant même toute vérification par les méthodes de classification, Jean Séguy systématisa, pour l’ensemble gascon, sous le titre gradient de gasconité dans ALG 6. De là à formuler l’hypothèse d’une organisation en fractales, il n’y a qu’un pas ; et ce pas n’est pas d’ordre métaphorique : le travail de vérification qui reste à faire, à partir de là, est immense et fascinant.From Lalanne–1950 to Séguy–1973 (ALG 6 Gasconish Dialectometry), there is a long way. From Lalanne Maritim Gasconish dialectal data base to Linguistic Gradual Sets and Fuzzy Subsets (ALG 6 phonetic data; phonological data; morphosyntactic data; lexical data Fuzzy Sets): we have now achived to validate the first hypotesis on dialectal organization by Fuzzy Sets and Subsets. And now? what does say us about Dialectal Organization by “Ward’s Method” of Distance Calculation? and how calculate that we name “Dialectal Fractals”? That is the crucial question

Ny Odense: Byudvikling og den politiserede byidentitet

Der bliver revet ned og bygget nyt i centrum af Odense i disse år med en hast, som ikke er set siden 1960’erne. Denne artikel beskæftiger sig med baggrunden for de store projekter og undersøger, hvilke problemer der er blevet opfattet som de centrale i nyere byudviklingspolitik i Odense. Problemer, der blev opfattet som lokale, indgik i en transnational udveksling af byudviklingspolitik, der lagde vægt på at fremelske en kreativ økonomi. De politiske problemrepræsentationer i Odense satte byens identitet i spil

Revolution i detailhandlen? Om Marshall-plan, studierejser og selvbetjeningsbutikker.

Artiklen undersøger, hvordan udbredelsen af selvbetjeningsbutikker i Danmark var en del af Marshall-planens målsætning. Ved at fokusere på en af de rejser om selvbetjening, der blev arrangeret i Marshall-regi, kan det vises, hvordan oprettelsen af selvbetjeningsbutikker både var i overensstemmelse med amerikanske og danske ønsker. I den danske detailhandel var især kooperationen interesseret i de nye principper, men der fandtes også skeptiske stemmer, der advarede mod de amerikanske ideer.AbstractThe article explores how the dissemination of self-service shops in Denmark was an integral part of the Marshall Plan. Focusing on one of those journeys under the auspices of the Marshall Plan to study such self-service shops in the USA, the article shows how the creation of self-service shops was in accordance with American as well as Danish aspirations. In the Danish retailing business, particularly the cooperative movement was interested in the new principles, even if sceptical voices cautioned against these American ideas. Outside these circles, the Danish unions and employers’ organizations supported the intentions to modernize what they considered an expensive link in the retail trade. The gain in productivity pursued by the industry was considered to depend not only on increasing consumption, but also on standardized goods and mass consumption

NORD FOR VESTTYSKLAND, VEST FOR STOREBÆLT: TV 2 MELLEM SATELLITTER OG REGIONAL-TV, 1967-91

Sissel Bjerrum Fossat: Nord for Vesttyskland, vest for Storebælt: TV 2 mellem satellitter og regional-tv, 1967-91 Artiklen afdækker hvordan placeringen af TV 2 i både fysisk og kulturel geografi afspejlede teknologiske, politiske og mediehensyn. De tidlige politiske ønsker om et TV 2 tog udgangspunkt i de forventninger 1960ernes kommunikationssatellitter skabte. En ny dansk kanal ville kunne dæmme op for udenlandsk TV-påvirkning, og en ny dansk kanal kunne sågar tænkes som en del af en fælles nordisk satellit-løsning. Det viste sig imidlertid, at der skulle vælges mellem den nordiske løsning og et TV 2 med tilknyttede regionalkanaler; satellitteknologien ikke kunne rumme begge løsninger. Resultatet blev et provinsnært TV 2, der tog udgangspunkt i forestillingen om et stærkt folkeligt fællesskab uden for hovedstadens elitære kredse. Da TV 2 blev en realitet i 1986, fik stationen gennem bestyrelsen sin egen stemme, og mediehensyn blev en langt tydeligere del af TV 2’s udvikling. I denne tidlige del af TV 2’s historie vejede politiske hensyn imidlertid stadig tungest, og selvom bestyrelsen argumenterede meget grundigt for en placering i København ud fra stationens egne behov, så var der ingen tvivl om, at det måtte være de politiske ønsker om et TV 2 i provinsen, der skulle vægtes højest