A Note on the Reliability Tests of Estimates from ARMS Data

USDA uses the concept of "publish-ability" rather than statistical reliability of an estimate for quality validation of USDA estimates, which is solely based on the sample size and the coefficient of variation (CV). We demonstrate conceptually how the reliability of the sample mean can be tested by estimating the upper and lower bounds of the confidence interval for an unknown population mean using the CV. However, the reliability test for the sample mean can be made only under the normality assumption. USDA multiple-way Agricultural Resource Management Survey (ARMS) estimates are used to illustrate the relative measure of precision for sample-based estimators.Research Methods/ Statistical Methods,

Zero material dispersion in optical fibres

The material dispersion of optical fibres having cores of silica or phosphosilicate glass falls to zero at a wavelength between 1.2 and 1.3µm. A considerable increase in bandwidth can be obtained, especially with an l.e.d. source, by operation in this region

Preparation of water-free silica-based optical-fibre waveguide

A technique is described, whereby the hydroxyl absorption bands of the new phosphosilicate-core optical-fibre waveguide, which arise from impurities in the cladding, can be largely eliminated. The resulting fibre has ultralow loss over the entire wavelength range 0.4-1.1µm

Dispersion in low-loss liquid-core optical fibres

Measurements of pulse dispersion in liquid-core multimode fibres have been made for different fibre curvatures and core diameters. The results indicate the presence of mode-conversion effects, and a mode-filtering mechanism is demonstrated with a probing beam of narrow angular width. By measuring transmission loss as a function of angle of incidence, the loss in the cladding material is obtained

Routine characterisation of single-mode fibres

In single-mode fibres. the core diameter and refractive-index difference between core and cladding may be found from the widths of (a) the halfpower points and (b) the first minimum of the far-field radiation. The technique has been used to study the effect of heat treatment

Pulse dispersion in glass fibres

Measurements indicate that pulses incident normally on the end of a cladded multimode fibre are broadened by less than 0.1 ns over a length of 20 m. The measured dispersions in lengths of 20 m and 35 m do not exceed 5 ps/m. However, with an angle of incidence of 17°, or with a defocused input beam, the pulses are broadened by 0.6 ns

Global dynamics above the ground state for the nonlinear Klein-Gordon equation without a radial assumption

We extend our previous result on the focusing cubic Klein-Gordon equation in three dimensions to the non-radial case, giving a complete classification of global dynamics of all solutions with energy at most slightly above that of the ground state.Comment: 40 page