Evaporative cooling in the zebra finch

Zusammenfassung O₂-Verbrauch und Gesamt-Wasserverdunstung wurden bei australischen Zebrafinken gemessen. Bei geringem Wärmeaustausch zwischen Körper und Umgebung durch Strahlung, Konvektion und Ableitung können diese Wüstenvögel den für die Wärmebilanz erforderlichen Wärmeabfluss einzig durch Verdunstung auf dem normalen Niveau halten. Eine solche Fähigkeit ist bei Passeres bisher nicht beobachtet worden.

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This investigation was supported in part by funds provided for medical and biological research by State of Washington Initiative Measure No. 171, and in part by a Public Health Service research career program award (No. AM-K3-18, 370) from the National Institute of Arthritis and Metabolic Diseases.     

A neurite-receptor complex in the avian lung: Electron microscopical observations

Résumé L'examen au microscope électronique du bronchus primaire intrapulmonaire deGallus domesticus a révelé la présence d'un complexe neurite-récepteur très semblable aux cellules du glomus carotidien des mammifères, et aux cellules de Merkel qui se trouvent dans les structures épidermiques des vertébrés. La fonction possible chémorécepteur ou méchanorécepteur de ces cellules est discutée.     

Recent temperature trends in the Antarctic

It is important to understand how temperatures across the Antarctic have changed in recent decades because of the huge amount of fresh water locked into the ice sheet and the impact that temperature changes may have on the ice volume. Doran et al. claim that there has been a net cooling of the entire continent between 1966 and 2000, particularly during summer and autumn. We argue that this result has arisen because of an inappropriate extrapolation of station data across large, data-sparse areas of the Antarctic.     

Rheogoniometric viscosity measurements of whole human blood at minimal shear rates down to 0.0009 sec−1

Zusammenfassung Messungen menschlichen Gesamtblutvolumens bei sehr niedrigen Schubzeiten bis 0,0009 sec^–1 (modifizierter Weissenberg-Rheogoniometer). Es wird gefunden, dass das Blut kein Newton'sches Verhalten und bei diesen niedrigen Schubzeitableitungen eine Fliessspannung aufweist.     

Genome sequence of Silicibacter pomeroyi reveals adaptations to the marine environment

Since the recognition of prokaryotes as essential components of the oceanic food web, bacterioplankton have been acknowledged as catalysts of most major biogeochemical processes in the sea. Studying heterotrophic bacterioplankton has been challenging, however, as most major clades have never been cultured or have only been grown to low densities in sea water. Here we describe the genome sequence of Silicibacter pomeroyi, a member of the marine Roseobacter clade (Fig. 1), the relatives of which comprise approximately 10-20% of coastal and oceanic mixed-layer bacterioplankton. This first genome sequence from any major heterotrophic clade consists of a chromosome (4,109,442 base pairs) and megaplasmid (491,611 base pairs). Genome analysis indicates that this organism relies upon a lithoheterotrophic strategy that uses inorganic compounds (carbon monoxide and sulphide) to supplement heterotrophy. Silicibacter pomeroyi also has genes advantageous for associations with plankton and suspended particles, including genes for uptake of algal-derived compounds, use of metabolites from reducing microzones, rapid growth and cell-density-dependent regulation. This bacterium has a physiology distinct from that of marine oligotrophs, adding a new strategy to the recognized repertoire for coping with a nutrient-poor ocean.     

Decoherence of quantum superpositions through coupling to engineered reservoirs

The theory of quantum mechanics applies to closed systems. In such ideal situations, a single atom can, for example, exist simultaneously in a superposition of two different spatial locations. In contrast, real systems always interact with their environment, with the consequence that macroscopic quantum superpositions (as illustrated by the 'Schrodinger's cat' thought-experiment) are not observed. Moreover, macroscopic superpositions decay so quickly that even the dynamics of decoherence cannot be observed. However, mesoscopic systems offer the possibility of observing the decoherence of such quantum superpositions. Here we present measurements of the decoherence of superposed motional states of a single trapped atom. Decoherence is induced by coupling the atom to engineered reservoirs, in which the coupling and state of the environment are controllable. We perform three experiments, finding that the decoherence rate scales with the square of a quantity describing the amplitude of the superposition state.