62 research outputs found
Skin microvascular reactivity in children and adolescents with type 1 diabetes in relation to levels of physical activity and aerobic fitness
No studies to date have evaluated the relationship between exercise and microvascular function in youth with type 1 diabetes mellitus (T1DM). Twenty-nine complication free children and adolescents with T1DM were assessed for skin microvascular reactivity, aerobic fitness (VO2peak) and physical activity. VO2peak but not physical activity was significantly and independently associated with maximal hyperemia of the skin microcirculation (p < .01). No significant associations were found between venoarteriolar reflex (VAR) vasoconstriction and VO2peak or physical activity. Aerobic fitness may be an important indicator or mediator of effective microvascular endothelial function in youth with T1DM
Creation of NOON states by double Fock-state/Bose-Einstein condensates
NOON states (states of the form where and
are single particle states) have been used for predicting violations of
hidden-variable theories (Greenberger-Horne-Zeilinger violations) and are
valuable in metrology for precision measurements of phase at the Heisenberg
limit. We show theoretically how the use of two Fock state/Bose-Einstein
condensates as sources in a modified Mach Zender interferometer can lead to the
creation of the NOON state in which and refer to arms of the
interferometer and is the total number of particles in the two condensates.
The modification of the interferometer involves making conditional ``side''
measurements of a few particles near the sources. These measurements put the
remaining particles in a superposition of two phase states, which are converted
into NOON states by a beam splitter. The result is equivalent to the quantum
experiment in which a large molecule passes through two slits. The NOON states
are combined in a final beam splitter and show interference. Attempts to detect
through which ``slit'' the condensates passed destroys the interference.Comment: 8 pages 5 figure
An organizational impression management perspective on the formation of corporate reputations
Researchers have only recently turned their attention to the study of corporate reputation. As is characteristic of many early areas of management inquiry, the field is decidedly multidisciplinary and disconnected. This article selectively reviews reputation research conducted mainly during the past decade. A framework is proposed that views reputation from the perspective of organizational impression management. Corporations are viewed as social actors, intent on enhancing their respectability and impressiveness in the eyes of constituents
Planned geological investigations of the Europa Clipper mission
Geological investigations planned for the Europa Clipper mission will examine the formation, evolution, and expression of geomorphic structures found on the surface. Understanding geologic features, their formation, and any recent activity are key inputs in constraining Europa’s potential for habitability. In addition to providing information about the moon’s habitability, the geologic study of Europa is compelling in and of itself. Here we provide a high-level, cross-instrument, and cross-discipline overview of the geologic investigations planned within the Europa Clipper mission. Europa’s fascinating collection of ice-focused geology provides an unparalleled opportunity to investigate the dynamics of icy shells, ice-ocean exchange processes, and global-scale tectonic and tidal stresses. We present an overview of what is currently known about the geology of Europa, from global to local scales, highlighting outstanding issues and open questions, and detailing how the Europa Clipper mission will address them. We describe the mission’s strategy for searching for and characterizing current activity in the form of possible active plumes, thermal anomalies, evidence for surface changes, and extremely fresh surface exposures. The complementary and synergistic nature of the data sets from the various instruments and their integration will be key to significantly advancing our understanding of Europa’s geology
Phylogenomics and the rise of the angiosperms
Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5,6,7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade
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A programmable autosampler for a field deployable tritium analysis system
Researchers in the Environmental Technology Section of the Savannah River Technology Center, in cooperation with Sampling Systems, Inc. are developing a fully programmable, remotely operated, fixed volume, automatic sampler for use with the field deployable tritium analysis system currently under development at U. of GA`s Center for Applied Isotope Studies. The sampler will collect a limited-volume sample and perform on-line sample purification for tritium analyses from multiple collection sites. Pneumatically operated stainless steel samplers operate satisfactorily upon remote activation. The one-step purification system removes all impurities with interfere with tritium analysis by liquid scintillation. Field testing has confirmed system operation. The autosampler may act as a stand-alone device and is enclosed in a rugged, field-portable case with wheels. The system weighs about 40 lbs
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