2,641 research outputs found
Imprints of log-periodic self-similarity in the stock market
Detailed analysis of the log-periodic structures as precursors of the
financial crashes is presented. The study is mainly based on the German Stock
Index (DAX) variation over the 1998 period which includes both, a spectacular
boom and a large decline, in magnitude only comparable to the so-called Black
Monday of October 1987. The present example provides further arguments in
favour of a discrete scale-invariance governing the dynamics of the stock
market. A related clear log-periodic structure prior to the crash and
consistent with its onset extends over the period of a few months. Furthermore,
on smaller time-scales the data seems to indicate the appearance of analogous
log-periodic oscillations as precursors of the smaller, intermediate decreases.
Even the frequencies of such oscillations are similar on various levels of
resolution. The related value of preferred scaling ratios
is amazingly consistent with those found for a wide variety of other complex
systems. Similar analysis of the major American indices between September 1998
and February 1999 also provides some evidence supporting this concept but, at
the same time, illustrates a possible splitting of the dynamics that a large
market may experience.Comment: 13 pages, LaTeX-REVTeX, 4 PS figures. Significantly extended version
to appear in The European Physical Journal
Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber
Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber is experimentally and numerically investigated. Guiding light in such fiber occurs via two mechanisms: photonic bandgap in the central silica core or total internal reflection in the germanium doped inclusions. By properly combining spectral filtering, dispersion tailoring and pump coupling into the fiber modes, we experimentally demonstrate efficient supercontinuum generation with controllable spectral bandwidth
Estimates of abundance : VIMS small fish trawl survey, York and Rappahannock Rivers, 1955 to 1982
This report presents information on catch of iuvenile fish with a 30 ft. semi-ballon trawl in the York and Rappahannock Rivers, and graphically compares those with the commercial landings in Virqinia waters for the years 1955 throuqh part of 1982
Battery-Operated Atomic Force Microscope
The design of a battery-operated atomic force microscope (AFM) using a piezoresistive cantilever is described. The AFM is designed so that all power to drive the scanning tube and detection electronics comes from a self-contained battery. The prototype AFM uses a 6 V, Ni–Cd, camcorder battery, however, any battery that supplies between 6 and 12 V may be used. Scanner control and data acquisition are implemented using commercially available software running on an external computer. The prototype AFM achieves a scan area of 53 by 53 μm, consumes 1.8 W of power, and can scan continuously for about 7 h on a single battery charge
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