National Institute of Oceanography, India

About: National Institute of Oceanography, India is a facility organization based out in Panjim, Goa, India. It is known for research contribution in the topics: Monsoon & Population. The organization has 4713 authors who have published 6927 publications receiving 174272 citations.

The distribution of intervals between zeros of a stationary random function

Abstract: The probability density P m of the spacing between the i th zero and the ( i + m + 1)th zero of a stationary, random function f ( t ) (not necessarily Gaussian) is expressed as a series, of a type similar to that given by Rice (1945) but more rapidly convergent. The partial sums of the series provide upper and lower bounds successively for P m . The series converges particularly rapidly for small spacings r . It is shown that for fixed values of r , the density P m ( r ) diminishes more rapidly than any negative power of m . The results are applied to Gaussian processes; then the first two terms of the series for P m ( T ) may be expressed in terms of known functions. Special attention is paid to two cases: (1) In the ‘regular’ case the covariance function i/r( t ) is expressible as a power series in then P m ( r ) is of order r 1/2 (m+2)(m+3)-2 at the origin, and in particular P ( r ) is of order r (adjacent zeros have a strong mutual repulsion). The first two terms of the series give the value of P 0 ( t ) correct to r 18 . (2) In a singular case, the covariance function p( t ) has a discontinuity in the third derivative. This happens whenever the frequency spectrum of f(t ) is O (frequency) -4 at infinity. Then P m ( r ) is shown to tend to a positive value P m (0) as r -> 0 (neighbouring zeros are less strongly repelled). Upper and lower bounds for P m (0) ( m = 0, 1, 2, 3) are given, and it is shown th at P 0 (0) is in the neighbourhood of 1.155^ m ( - 6^ 9) . The conjecture of Favreau, Low & Pfeffer (1956) according to which in one case P 0 ( t ) is a negative exponential, is disproved. In a final section, the accuracy of other approximations suggested by Rice (1945), McFadden (1958), Ehrenfeld et al . (1958) and the present author (1958) are compared and the results are illustrated by computations, the frequency spectrum of f(t ) being assumed to have certain ideal forms: a low-pass spectrum, band-pass spectrum, Butterworth spectrum, etc.

The Vertical Distribution of Pelagic Decapods [Crustacea: Natantia] Collected on the Sond Cruise 1965 I. The Caridea

Abstract: This study forms a contribution to a series (Angel, 1969; Clarke, 1969; Baker, 1970; Badcock, 1970) describing the biological results of a detailed investigation of the ecology of an oceanic area located in the eastern North Atlantic, close to the island of Fuerteventura (Canary Islands). The scientific background and objectives of the investigation, conducted during September to December 1965, have been described elsewhere (Currie, Boden & Kampa, 1969). Our main interest lay in the biological composition and acoustic characteristics of sonic scattering layers, and it was therefore considered essential to sample the principal elements of the pelagic fauna within the depth range 0–1000 m in as quantitative and detailed a manner as was technically possible. The resulting biological collections represent a unique body of material, the analysis of which is directly pertinent to the vertical distribution, diurnal migration and ecological interrelationships of the mesopelagic fauna.