A chromatic dispersion monitoring scheme for flexible optical OFDM networks is presented. Coded label subcarriers are added to the signal spectrum and dispersion monitoring is performed via direct detection, followed by electronic correlation procedures. OCIS codes: (060.0060) Fiber optics and optical communications

In character recognition, zoning based feature extraction is one of the most popular methods. The character image is divided into predefined number of zones and a feature is computed from each of these zones. Usually, this feature is based on the pattern (black) pixels contained in that zone. Some of such features are average pixel density, sum squared distance, histogram. But in such features,...

The optical conductivity of CuO2 (copper-oxygen) planes in p and n–type cuprates thin films at various doping levels is deduced from highly accurate reflectivity data. The temperature dependence of the real part σ1(ω) of this optical conductivity and the corresponding spectral weight allow to track the opening of a partial gap in the normal state of n-type Pr2−xCexCuO4 (PCCO), but not of p–type...

Changes in the effective optical density of the cones are sufficient to explain changes in color matches with retinal illuminance and pupil entry. We performed three experiments. In the first experiment, six observers made color matches under both bleached and unbleached conditions to a series of six standard wavelengths. The effects of bleaching could be modeled by a decrease in optical densit...

High-resolution Halpha rotation curves are presented for five low surface brightness galaxies. These Halpha rotation curves have shapes different from those previously derived from H i observations, probably because of the higher spatial resolution of the Halpha observations. The Halpha rotation curves rise more steeply in the inner parts than the H i rotation curves, and they reach a flat part...

The mutual adhesion of slime-mould cells was investigated at 24 and 1 °C in stirred and unstirred medium. Adhesion was induced by adding sodium chloride and followed by recording the diminution in optical density of the cell suspension associated with the formation of cell aggregates. It was found that: (1) when cells, previously stored at 1 °C, were stirred in distilled water at 24 C the optic...

In reflection plethysmography at the finger inverted pulsewaves are sometimes observed, especially when, during anaesthesia, arterial pressure is measured in the same arm with an inflatable cuff. The origin of this inversion is investigated to two series experiments with volunteers. In the first series of experiments the influence of the pressure in the upper arm cuff was investigated and in th...

The current work aimed to evaluate the cross-reactivity of human immune sera against crude hydatid fluid antigens of sheep, human, mouse, cattle, as well as B fraction of cystic fluid antigen. 30 balb/c mice were infected with sheep hydatid cyct fluid antigen containing protoscolex after the viability of these protoscolices was assessed. ANOVA was used to test the difference of themean of optic...

[1] We use the ‘‘observation minus reanalysis’’ difference (OMR) method to estimate the impact of land-use changes by computing the difference between the trends of the surface temperature observations (which reflect all the sources of climate forcing, including surface effects) and the NCEP-NCAR reanalysis surface temperatures (only influenced by the assimilated atmospheric temperature trends)...

This paper presents visibility distances from twenty people who have viewed six internally illuminated elements of emergency lighting systems or wayguidance systems, under different ambient lighting, in smoke. The optical density of the smoke ranges from 0.8 m to 1.4 m. The six elements investigated are four emergency exit signs with graphical symbol formats and two types of exit door markings....