1,305 research outputs found
On the support of solutions to the Zakharov-Kuznetsov equation
In this article we prove that sufficiently smooth solutions of the
Zakharov-Kuznetsov equation that have compact support for two different times
are identically zero.Comment: Version of Dec 17/2010 contains simpler proof of Theorem 1.3 and new
references are adde
Cricket antennae shorten when bending (Acheta domesticus L.).
Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to "unfold" and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head
"El carĂĄcter absoluto del dominio" : el pensamiento de VĂ©lez Sarsfield
Fil: Bustamente Alsina, Jorge Horacio. Universidad de Buenos Aires. Facultad de Derecho. CĂĄtedra Derecho Civil IV. Buenos Aires, Argentin
A General Approach to Discrete-Time Adaptive Control Systems with Perturbed Measures for Complex Dynamics - Case Study: Unmanned Underwater Vehicles
Structuring Direct Investment in Latin America: Keeping Pace with New Financial Regimes, Innovative Investment Vehicles, and Changing Labor Laws
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