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Gullies on Mars: Origin by snow and ice melting and potential for life based on possible analogs from Devon Island, High Arctic
Gullies on Devon Island, High Arctic, which form by melting of transient surface ice and snow covers and offer morphologic and contextual analogs for gullies reported on Mars are reported to display enhancements in biological activity in contrast to surrounding polar desert terrain
A Novel Long-term, Multi-Channel and Non-invasive Electrophysiology Platform for Zebrafish.
Zebrafish are a popular vertebrate model for human neurological disorders and drug discovery. Although fecundity, breeding convenience, genetic homology and optical transparency have been key advantages, laborious and invasive procedures are required for electrophysiological studies. Using an electrode-integrated microfluidic system, here we demonstrate a novel multichannel electrophysiology unit to record multiple zebrafish. This platform allows spontaneous alignment of zebrafish and maintains, over days, close contact between head and multiple surface electrodes, enabling non-invasive long-term electroencephalographic recording. First, we demonstrate that electrographic seizure events, induced by pentylenetetrazole, can be reliably distinguished from eye or tail movement artifacts, and quantifiably identified with our unique algorithm. Second, we show long-term monitoring during epileptogenic progression in a scn1lab mutant recapitulating human Dravet syndrome. Third, we provide an example of cross-over pharmacology antiepileptic drug testing. Such promising features of this integrated microfluidic platform will greatly facilitate high-throughput drug screening and electrophysiological characterization of epileptic zebrafish
Double-heterostructure GaAs-GaAIAs injection lasers on semi-insulating substrates using carrier crowding
GaAs‐GaAlAs double‐heterostructure lasers were fabricated on semi‐insulating substrates. Laser action based on carrier confinement via the crowding effect has been demonstrated. Laser action takes place in a narrow (10–20 μm) region near the edge of the mesa where the current is injected. The threshold current is low and is comparable to that of stripe‐geometry lasers
On Inhomogeneity of a String Bit Model for Quantum Gravity
We study quantum gravitational effect on a two-dimensional open universe with
one particle by means of a string bit model. We find that matter is necessarily
homogeneously distributed if the influence of the particle on the size of the
universe is optimized.Comment: 16 pages, LaTeX2
Direct transmission of pictorial information in multimode optical fibers
The problem of coherent image transmission through a single multimode optical fiber is discussed. A scheme is presented for recovering the transmitted image after distortions brought about by the fiber modes dispersion. Realization of this scheme by holographic techniques and with lens systems is proposed, and its limitations pointed out. The application of this scheme in canceling out temporal signal dispersion in a multimode fiber transmission line is also discussed briefly
Unitary Irreducible Representations of a Lie Algebra for Matrix Chain Models
There is a decomposition of a Lie algebra for open matrix chains akin to the
triangular decomposition. We use this decomposition to construct unitary
irreducible representations. All multiple meson states can be retrieved this
way. Moreover, they are the only states with a finite number of non-zero
quantum numbers with respect to a certain set of maximally commuting linearly
independent quantum observables. Any other state is a tensor product of a
multiple meson state and a state coming from a representation of a quotient
algebra that extends and generalizes the Virasoro algebra. We expect the
representation theory of this quotient algebra to describe physical systems at
the thermodynamic limit.Comment: 46 pages, no figure; LaTeX2e, amssymb, latexsym; typos correcte
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