Tardigrade

In two moss samples collected from Turkey four tardigrade species, including a species new for science and a new recordfor the country, were found. The new species, Milnesium beasleyi sp. nov., differs from other known species of the gran-ulatum group by having sparsely distributed cuticular depressions (pseudopores) that do not form an apparent reticulum.In addition to the unique cuticular sculpturing, the new species differs from other congeners also by some morphometriccharacters. Macrobiotus reinhardti Michalczyk & Kaczmarek, 2003 is a new record for Turkey and it is also the first re-cord of this species outside its type locality on Cyprus. The new records raise the number of known Turkish water bearspecies to 50. In this paper, we provide a full list of the known Turkish tardigrade species with their localities. Moreover, we present some zoogeographical and taxonomic issues concerning Turkish tardigrades.

Survival in microhabitats that experience extreme fluctuations in water availability and temperature requires special adaptations. To withstand such environmental conditions, tardigrades, as well as some nematodes and rotifers, enter a completely desiccated state known as anhydrobiosis. We examined the effects of high temperatures on fully desiccated (anhydrobiotic) tardigrades. Nine species from the classes Heterotardigrada and Eutardigrada were exposed to temperatures of up to 110 degrees C for 1 h. Exposure to temperatures of up to 80 degrees C resulted in a moderate decrease in survival. Exposure to temperatures above this resulted in a sharp decrease in survival, with no animals of the families Macrobiotidae and Echiniscidae surviving 100 degrees C. However, Milnesium tardigradum (Milnesidae) showed survival of >90% after exposure to 100 degrees C; temperatures above this resulted in a steep decrease in survival. Vitrification is assumed to play a major role in the survival of anhydrobiotic organisms during exposure to extreme temperatures, and consequently, the glass-transition temperature (T(g)) is critical to high-temperature tolerance. In this study, we provide the first evidence of the presence of a glass transition during heating in an anhydrobiotic tardigrade through the use of differential scanning calorimetry.

Tardigrades are microscopic animals, commonly referred to as “water bears”, and comprise the phylum Tardigrada. They are found in diverse habitats in terrestrial, freshwater and marine environments worldwide. In this paper, it is presented a brief history of the study of tardigrades in Brazil and an updated species checklist of Brazilian tardigrades. Since the first report in 1913, the number of tardigrades records has increased, reflecting advances in the understanding the diversity of tardigrades in Brazil. A total of 100 species known from Brazil are listed, being 30 in marine and 70 in terrestrial and freshwater environments. The records are concentrated in Southeast (47.1%) and Northeast (41.3%) regions. Despite the advances, further research and sampling of new areas is still needed, besides reanalysis and confirmation of old records. Brazil, with its vast territory, extensive continental shelf and great diversity of biomes, has great potential to expand our knowledge of tardi...

Si vous suivez les discussions des scientifiques quantiques, vous aurez l'impression que la science quantique n'a pas encore vraiment défini ses standards, surtout concernant les *états superposés*. C'est d'autant plus difficile à la comprendre quand on est profane. Cette réalité m'a conduit à partager le peu que j'ai compris dans ce domaine pour éclairer tant soit peu le commun des mortels.


Illustration des sciences quantiques par
un MODÈLE MACROSCOPIQUE D'INTRICATION QUANTIQUE :


A. Billet de banque, pièce de monnaie...

Imaginez qu'un Marsien arrive sur Terre et demande de voir notre symbole des échanges. On lui présente un billet de banque ou une pièce de monnaie sur la face portant l'effigie. Il rentre sur Mars et rapporte que leur système des changes est un papier ou une pièce métallique portant une effigie.

Un autre Marsien vient sur Terre et on lui présent le même billet par la face portant le dessin du Pentagone ou de la Maison Blanche. Il rentre sur Mars et raconte : « ils ont deux symboles des échanges, le premier que nous connaissons déjà et qui porte une effigie, et un deuxième qui ne porte pas d'effigie ».