3,402 research outputs found
An early Anglo-Saxon bridle-fitting from South Leckaway, Forfar, Angus, Scotland
[FIRST PARAGRAPH] In February 2003 the Kinnettles Heritage Group made a quite unexpected find during field-walking at South Leckaway farm near Forfar, Angus (NGR NO 4379 4810): the most northerly example in Britain — by about 150 miles — of an Anglo- Saxon object decorated in Salin’s Style I. It lay isolated and face down on the surface. A follow-up field-walk at the end of the month confirmed, partly with the aid of a metal detector, that there were no readily apparent additional pieces of metalwork, associated structures or burial evidence. The find was reported under the Scottish Treasure Trove legislation, duly claimed and allocated in June 2003 to the Meffan Institute, Forfar (part of Angus Cultural Services)
New hydrogen-like potentials
Using the modified factorization method introduced by Mielnik, we construct a
new class of radial potentials whose spectrum for l=0 coincides exactly with
that of the hydrogen atom. A limiting case of our family coincides with the
potentials previously derived by Abraham and MosesComment: 6 pages, latex, 2 Postscript figure
Numerical simulation of dark lanes in post-flare supra-arcade
We integrate the MHD ideal equations to simulate dark void sunwardly moving
structures in post--flare supra--arcades. We study the onset and evolution of
the internal plasma instability to compare with observations and to gain
insight into physical processes and characteristic parameters of these
phenomena. The numerical approach uses a finite-volume Harten-Yee TVD scheme to
integrate the 1D1/2 MHD equations specially designed to capture supersonic flow
discontinuities. The integration is performed in both directions, the sunward
radial one and the transverse to the magnetic field. For the first time, we
numerically reproduce observational dark voids described in Verwichte et al.
(2005). We show that the dark tracks are plasma vacuums generated by the
bouncing and interfering of shocks and expansion waves, upstream an initial
slow magnetoacoustic shock produced by a localized deposition of energy modeled
with a pressure perturbation. The same pressure perturbation produces a
transverse to the field or perpendicular magnetic shock giving rise to
nonlinear waves that compose the kink--like plasma void structures, with the
same functional sunward decreasing phase speed and constancy with height of the
period, as those determined by the observations.Comment: Accepted MNRAS, 6 pages, 7 figure
Heuristic-based firefly algorithm for bound constrained nonlinear binary optimization
Firefly algorithm (FA) is a metaheuristic for global optimization. In this paper,we address the practical testing of aheuristic-based FA (HBFA) for computing optimaof discrete nonlinear optimization problems,where the discrete variables are of binary type. An important issue in FA is the formulation of attractiveness of each firefly which in turn affects its movement in the search space. Dynamic updating schemes are proposed for two parameters, one from the attractiveness term and the other from the randomization term. Three simple heuristics capable of transforming real continuous variables into binary ones are analyzed. A new sigmoid ‘erf’ function is proposed. In the context of FA, three different implementations to incorporate the heuristics for binary variables into the algorithm are proposed. Based on a set of benchmark problems, a comparison is carried out with other binary dealing metaheuristics. The results demonstrate that the proposed HBFA is efficient and outperforms binary versions of differential evolution (DE) and particle swarm optimization (PSO). The HBFA also compares very favorably with angle modulated version of DE and PSO. It is shown that the variant of HBFA based on the sigmoid ‘erf’ function with ‘movements in continuous space’ is the best, both in terms of computational requirements and accuracy.Fundação para a Ciência e a Tecnologia (FCT
Phase and group velocity tracing analysis of projected wave packet motion along oblique radar beams ? qualitative analysis of QP echoes
International audienceThe wave packets of atmospheric gravity waves were numerically generated, with a given characteristic wave period, horizontal wave length and projection mean wind along the horizontal wave vector. Their projection phase and group velocities along the oblique radar beam (vpr and vgr), with different zenith angle ? and azimuth angle ?, were analyzed by the method of phase- and group-velocity tracing. The results were consistent with the theoretical calculations derived by the dispersion relation, reconfirming the accuracy of the method of analysis. The RTI plot of the numerical wave packets were similar to the striation patterns of the QP echoes from the FAI irregularity region. We propose that the striation range rate of the QP echo is equal to the radial phase velocity vpr, and the slope of the energy line across the neighboring striations is equal to the radial group velocity vgr of the wave packet; the horizontal distance between two neighboring striations is equal to the characteristic wave period ?. Then, one can inversely calculate all the properties of the gravity wave responsible for the appearance of the QP echoes. We found that the possibility of some QP echoes being generated by the gravity waves originated from lower altitudes cannot be ruled out
Nurses\u27 Alumnae Association Bulletin - Volume 2 Number 3
The Jefferson Nurse
Letter from the President
Delegates to Biennial Convention
Attention
Blood Transfusion - Plasma Unit
Life in the Army Nurse Corps
Secretary\u27s Report
Elected to New Office
1892-1942
Progress or Alumnae Association 1892-1942
Report of the School of Nursing
Staff News
Please Change My Address
Air Cooled
Red Cross Report
Fingerprinting
Graduates in the U.S. Army and Navy
Degrees Received
Promotions
Jubilee Report
Engagements
Marriages
Births
New Positions - 1941-1942
New Positions on the Nursing Staff of the Hospita
Network analysis identifies weak and strong links in a metapopulation system
The identification of key populations shaping the structure and connectivity of metapopulation systems is a major challenge in population ecology. The use of molecular markers in the theoretical framework of population genetics has allowed great advances in this field, but the prime question of quantifying the role of each population in the system remains unresolved. Furthermore, the use and interpretation of classical methods are still bounded by the need for a priori information and underlying assumptions that are seldom respected in natural systems. Network theory was applied to map the genetic structure in a metapopulation system by using microsatellite data from populations of a threatened seagrass, Posidonia oceanica, across its whole geographical range. The network approach, free from a priori assumptions and from the usual underlying hypotheses required for the interpretation of classical analyses, allows both the straightforward characterization of hierarchical population structure and the detection of populations acting as hubs critical for relaying gene flow or sustaining the metapopulation system. This development opens perspectives in ecology and evolution in general, particularly in areas such as conservation biology and epidemiology, where targeting specific populations is crucial
The Synthesis, Characterisation and Potential of Eu 3+ Doped Molybdate Phosphors for White Light Emitting Diodes
A wide variety of Eu3+ doped molybdate phosphors were synthesised using the solid state reaction route
and their photoluminescent properties were compared. Their crystal structures were investigated. A relationship between cell size and emission intensity was apparent. The implications of this for phosphor design are discussed.The authors are grateful to the Technology Strategy Board (TSB) (UK) for financial funding in the form of
TSB Technology programs for the NovelLEDs program TP/6/EPH/6/S/K2522J and the EPSRC for funding the
PURPOSE program
Geometric Phases and Mielnik's Evolution Loops
The cyclic evolutions and associated geometric phases induced by
time-independent Hamiltonians are studied for the case when the evolution
operator becomes the identity (those processes are called {\it evolution
loops}). We make a detailed treatment of systems having equally-spaced energy
levels. Special emphasis is made on the potentials which have the same spectrum
as the harmonic oscillator potential (the generalized oscillator potentials)
and on their recently found coherent states.Comment: 11 pages, harvmac, 2 figures available upon request; CINVESTAV-FIS
GFMR 11/9
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