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Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01
(2007)Physics Letters BA measurement of the cosmic ray positron fraction e+ / (e+ + e-) in the energy range of 1-30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 106 is reached by identifying converted bremsstrahlung photons emitted from positrons.Journal Article -
Salmonella enterica serovar typhimurium exploits inflammation to compete with the intestinal microbiota
(2007)PLoS BiologyMost mucosal surfaces of the mammalian body are colonized by microbial communities (“microbiota”). A high density of commensal microbiota inhabits the intestine and shields from infection (“colonization resistance”). The virulence strategies allowing enteropathogenic bacteria to successfully compete with the microbiota and overcome colonization resistance are poorly understood. Here, we investigated manipulation of the intestinal microbiota ...Journal Article -
Force-induced unfolding of fibronectin in the extracellular matrix of living cells
(2007)PLoS BiologyWhether mechanically unfolded fibronectin (Fn) is present within native extracellular matrix fibrils is controversial. Fn extensibility under the influence of cell traction forces has been proposed to originate either from the force-induced lengthening of an initially compact, folded quaternary structure as is found in solution (quaternary structure model, where the dimeric arms of Fn cross each other), or from the force-induced unfolding ...Journal Article -
Understanding the Evolutionary Fate of Finite Populations: The Dynamics of Mutational Effects
(2007)PLoS BiologyThe most consistent result in more than two decades of experimental evolution is that the fitness of populations adapting to a constant environment does not increase indefinitely, but reaches a plateau. Using experimental evolution with bacteriophage, we show here that the converse is also true. In populations small enough such that drift overwhelms selection and causes fitness to decrease, fitness declines down to a plateau. We demonstrate ...Journal Article -
Numerical Representation of Three-dimensional Stereochemical Environments Using FRAU-descriptors
(2007)Croatica Chemica ActaNumerical representation of stereochemical environments using FRAU (Field-characterization for Reaction Analysis and Understanding)-descriptors has been investigated. Correlations were analyzed between the FRAU-descriptors and stereochemical environments around an oxygen atom of cyclohexanol with chair form and oxygen atoms of all of the diastereo isomers of 1,2- cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, and 1,2,3,4,5-c ...Journal Article -
Cytogenetic mapping and STR polymorphism of thwo candidate genes (DRD2 and HTR1D) for behavioural traits in four canids
(2007)Archives of Animal BreedingThe dopamine D2 receptor (DRD2) and serotonin receptors 1D (HTR1D) are candidate genes for behavioural traits. In the present study, we show chromosomal location and polymorphism of these genes in four species from the family Canidae: dog (CFA), red fox (VVU), arctic fox (ALA) and the Chinese raccoon dog (NPP). Using fluorescence in situ hybridisation (FISH) the DRD2 gene was localized in the following chromosomes: CFA5q12-13, VVU12q21, ...Journal Article -
Natural Selection on Female Life-History Traits in Relation to Socio-Economic Class in Pre-Industrial Human Populations
(2007)PLoS ONELife-history theory predicts that resource scarcity constrains individual optimal reproductive strategies and shapes the evolution of life-history traits. In species where the inherited structure of social class may lead to consistent resource differences among family lines, between-class variation in resource availability should select for divergence in optimal reproductive strategies. Evaluating this prediction requires information on ...Journal Article -
Simulated Effects of Soil Temperature and Salinity on Capacitance Sensor Measurements
(2007)SensorsDielectric measurement techniques are used widely for estimation of water contentin environmental media. However, factors such as temperature and salinity affecting thereadings require further quantitative investigation and explanation. Theoretical sensitivities ofcapacitance sensors to liquid salinity and temperature of porous media were derived andcomputed using a revised electrical circuit analogue model in conjunction with a ...Journal Article -
The generalized Lyapunov theorem and its application to quantum channels
(2007)New Journal of PhysicsWe give a simple and physically intuitive necessary and sufficient condition for a map acting on a compact metric space to be mixing (i.e. infinitely many applications of the map transfer any input into a fixed convergency point). This is a generalization of the 'Lyapunov direct method'. First we prove this theorem in topological spaces and for arbitrary continuous maps. Finally we apply our theorem to maps which are relevant in open ...Journal Article -
Quantifying Organismal Complexity using a Population Genetic Approach
(2007)PLoS ONEBackground Various definitions of biological complexity have been proposed: the number of genes, cell types, or metabolic processes within an organism. As knowledge of biological systems has increased, it has become apparent that these metrics are often incongruent. Methodology Here we propose an alternative complexity metric based on the number of genetically uncorrelated phenotypic traits contributing to an organism's fitness. This ...Journal Article