133,092 research outputs found
The cyclically presented groups with relators xi xi+k xi+l
Continuing Cavicchioli, RepovĆĄ, and Spaggiari's investigations into the cyclic presentations ăx1,...,xn | x ixi+kxi+l D 1 (1 †i †n)ă we determine when they are aspherical and when they define finite groups; in these cases we describe the groups' structures. In many cases we show that if the group is infinite then it contains a non-abelian free subgroup. © European Mathematical Society
Vortex Fluctuations in the Critical Casimir Effect of Superfluid and Superconducting Films
Vortex-loop renormalization techniques are used to calculate the magnitude of
the critical Casimir forces in superfluid films. The force is found to become
appreciable when size of the thermal vortex loops is comparable to the film
thickness, and the results for T < Tc are found to match very well with
perturbative renormalization theories that have only been carried out for T >
Tc. When applied to a high-Tc superconducting film connected to a bulk sample,
the Casimir force causes a voltage difference to appear between the film and
bulk, and estimates show that this may be readily measurable.Comment: 4 pages, 5 figures, Revtex 4, typo correctio
Bird Migration Through A Mountain Pass Studied With High Resolution Radar, Ceilometers, And Census
Autumnal migration was studied with high-resolution radar, ceilometer, and daily census in the area of Franconia Notch, a major pass in the northern Appalachian Mountains. Under synoptic conditions favorable for migration, broadfront movements of migrants toward the south passed over the mountains, often above a temperature inversion. Birds at lower elevations appeared to be influenced by local topography. Birds moving southwest were concentrated along the face of the mountain range. Birds appeared to deviate their flights to follow local topography through the pass. Specific migratory behavior was not associated with species or species groups. Under synoptic conditions unfavorable for southward migration, multimodal movements probably associated with local flights were as dense as the southward migrations described above. Avian migrants reacting to local terrain may result in concentrations of migrants over ridge summits or other topographic features
Recommended from our members
The relationship between poverty and childhood well-being in Great Britain
Measurement of time differences between luminous events Patent
Mechanism for measuring nanosecond time differences between luminous events using streak camer
- âŠ