6,558 research outputs found
A Transmissable Erosive Gastro-Enteritis of Cattle
A Widespread ocurrence of an unusual disease of cattle has appeared in Indiana dairy and beef herds. It was characterized clinically by fever, nasal discharge, erosions of the buccal mucosa, lameness, cough and profuse diarrhea and at necropsy by congestion, hemorrhages and erosions of the mucosa of the entire digestive tract and congestion of the upper portion of the respiratory system. The disease was readily transmitted to calves both by direct and indirect contact and by inoculation of filtrates of blood obtained from affected animals. It has been called transmissible erosive gastroenteritis of cattle
Optical Weak Link between Two Spatially Separate Bose-Einstein Condensates
Two spatially separate Bose-Einstein condensates were prepared in an optical
double-well potential. A bidirectional coupling between the two condensates was
established by two pairs of Bragg beams which continuously outcoupled atoms in
opposite directions. The atomic currents induced by the optical coupling depend
on the relative phase of the two condensates and on an additional controllable
coupling phase. This was observed through symmetric and antisymmetric
correlations between the two outcoupled atom fluxes. A Josephson optical
coupling of two condensates in a ring geometry is proposed. The continuous
outcoupling method was used to monitor slow relative motions of two elongated
condensates and characterize the trapping potential.Comment: 4 pages, 5 figure
Bolometric and UV Light Curves of Core-Collapse Supernovae
The Swift UV-Optical Telescope (UVOT) has been observing Core-Collapse
Supernovae (CCSNe) of all subtypes in the UV and optical since 2005. We present
here 50 CCSNe observed with the Swift UVOT, analyzing their UV properties and
behavior. Where we have multiple UV detections in all three UV filters (\lambda
c = 1928 - 2600 \AA), we generate early time bolometric light curves, analyze
the properties of these light curves, the UV contribution to them, and derive
empirical corrections for the UV-flux contribution to optical-IR based
bolometric light curves
Quantum reflection of atoms from a solid surface at normal incidence
We observed quantum reflection of ultracold atoms from the attractive
potential of a solid surface. Extremely dilute Bose-Einstein condensates of
^{23}Na, with peak density 10^{11}-10^{12}atoms/cm^3, confined in a weak
gravito-magnetic trap were normally incident on a silicon surface. Reflection
probabilities of up to 20 % were observed for incident velocities of 1-8 mm/s.
The velocity dependence agrees qualitatively with the prediction for quantum
reflection from the attractive Casimir-Polder potential. Atoms confined in a
harmonic trap divided in half by a solid surface exhibited extended lifetime
due to quantum reflection from the surface, implying a reflection probability
above 50 %.Comment: To appear in Phys. Rev. Lett. (December 2004)5 pages, 4 figure
Phase Sensitive Recombination of Two Bose-Einstein Condensates on an Atom Chip
The recombination of two split Bose-Einstein condensates on an atom chip is
shown to result in heating which depends on the relative phase of the two
condensates. This heating reduces the number of condensate atoms between 10 and
40% and provides a robust way to read out the phase of an atom interferometer
without the need for ballistic expansion. The heating may be caused by the
dissipation of dark solitons created during the merging of the condensates.Comment: 5 pages, 4 figure
Normal and Reverse Faulting Driven by the Subduction Zone Earthquake Cycle in the Northern Chilean Forearc
Despite its location in a convergent tectonic setting, the Coastal Cordillera of northern Chile between 21°S and 25°S is dominated by structures demonstrating extension in the direction of plate convergence. In some locations, however, normal faults have been reactivated as reverse faults, complicating the interpretation of long-term strain. In order to place these new observations in a tectonic context, we model stress changes induced on these faults by the subduction earthquake cycle. Our simulations predict that interseismic locking on the plate boundary encourages normal slip on fore-arc faults, which may result from elastic rebound due to interplate earthquakes or from seismic or aseismic motion that takes place within the interseismic period. Conversely, stress generated by strong subduction zone earthquakes, such as the 1995 Mw = 8.1 Antofagasta event, provides a mechanism for the reverse reactivation we document here. Upper plate fault slip in response to the low-magnitude stress changes induced by the subduction earthquake cycle suggests that the absolute level of stress on these faults is very low. Furthermore, seismic hazard analysis for northern Chile requires consideration of not only the plate boundary earthquake cycle but also the cycle on fore-arc faults that may or may not coincide with the interplate pattern. Though the relationships between permanent strain and deformation calculated using elastic models remain unclear, the compatibility of modeled stress fields with the distribution of fore-arc faulting suggests that interseismic strain accumulation and coseismic deformation on the subduction megathrust both play significant roles in shaping structural behavior in the upper plate
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