11,140 research outputs found
S-wave and p-wave scattering in a cold gas of Na and Rb atoms
Using improved experimentally based and
molecular potentials of NaRb, we apply the variable phase method to compute new
data for low energy scattering of Na atoms by Rb atoms and
Rb atoms. These are the scattering lengths and volumes, numbers of bound
states and effective ranges, which we use to obtain the low energy spin-change
cross section as functions of the system temperature and the isotope masses.
From an analysis of the contributions of s-wave and p-wave scatterings to the
elastic cross section we estimate temperatures below which only s-wave
scattering is dominant. We compare our quantal results to data obtained from
the semiclassical approximation. We supply evidence for the existence of a near
zero energy p-wave bound state supported by the singlet molecular potential.Comment: The article contains additional material and data (see abstract
In situ observations of trophic behaviour and locomotion of Princaxelia amphipods (Crustacea, Pardaliscidae) at hadal depths in four West Pacific Trenches
Peer reviewedPublisher PD
Calibration of the TWIST high-precision drift chambers
A method for the precise measurement of drift times for the high-precision
drift chambers used in the TWIST detector is described. It is based on the
iterative correction of the space-time relationships by the time residuals of
the track fit, resulting in a measurement of the effective drift times. The
corrected drift time maps are parametrised individually for each chamber using
spline functions. Biases introduced by the reconstruction itself are taken into
account as well, making it necessary to apply the procedure to both data and
simulation. The described calibration is shown to improve the reconstruction
performance and to extend significantly the physics reach of the experiment.Comment: 8 pages, 5 figure
Financial signal processing: a self calibrating model
Previous work on multifactor term structure models has proposed that the short rate process is a function of some unobserved diffusion process. We consider a model in which the short rate process is a function of a Markov chain which represents the 'state of the world'. This enables us to obtain explicit expressions for the prices of zero-coupon bonds and other securities. Discretizing our model allows the use of signal processing techniques from Hidden Markov Models. This means we can estimate not only the unobserved Markov chain but also the parameters of the model, so the model is self-calibrating. The estimation procedure is tested on a selection of U.S. Treasury bills and bonds.Bonds
Potential markets for a satellite-based mobile communications system
The objective of the study was to define the market needs for improved land mobile communications systems. Within the context of this objective, the following goals were set: (1) characterize the present mobile communications industry; (2) determine the market for an improved system for mobile communications; and (3) define the system requirements as seen from the potential customer's viewpoint. The scope of the study was defined by the following parameters: (1) markets were confined to U.S. and Canada; (2) range of operation generally exceeded 20 miles, but this was not restrictive; (3) the classes of potential users considered included all private sector users, and non-military public sector users; (4) the time span examined was 1975 to 1985; and (5) highly localized users were generally excluded - e.g., taxicabs, and local paging
Bioaccumulation of persistent organic pollutants in the deepest ocean fauna
The Kermadec and Mariana âHADESâ expeditions (RV Thomas G. Thompson TN309, and RV Falkor FK141109) were funded through the National Science Foundation (NSF-OCE nos 1130712 and 1140494) and the Schmidt Ocean Institute. S.B.P. was supported by a Fellowship from the Leverhulme Trust. The analytical costs were supported by the Total Foundation (France) and the Marine Alliance for Science and Technology, Scotland (MASTS) through a Deep Sea Forum small grant award.Peer reviewedPostprin
Alien Registration- Jamieson, Harold J. (Presque Isle, Aroostook County)
https://digitalmaine.com/alien_docs/33722/thumbnail.jp
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