The composite-tendency Robert-Asselin-Williams (RAW) filter in semi-implicit integrations

Timediscretization in weatherandclimate modelsintroduces truncation errors that limit the accuracy of the simulations. Recent work has yielded a method for reducing the amplitude errors in leap-frog integrations from first-order to fifth-order.This improvement is achieved by replacing the Robert–Asselin filter with the Robert–Asselin–Williams (RAW) filter and using a linear combination of unfiltered and filtered states to compute the tendency term. The purpose of the present article is to apply the composite-tendency RAW-filtered leapfrog scheme to semi-implicit integrations. A theoretical analysis shows that the stability and accuracy are unaffected by the introduction of the implicitly treated mode. The scheme is tested in semi-implicit numerical integrations in both a simple nonlinear stiff system and a medium-complexity atmospheric general circulation model and yields substantial improvements in both cases. We conclude that the composite-tendency RAW-filtered leap-frog scheme is suitable for use in semi-implicit integrations.

Bathymetric distribution of the shrimp Rimapenaeus constrictus (Stimpson, 1874) (Decapoda, Penaeidae) in two locations off the southeastern Brazilian coast

The distribution of benthic organisms is directly or indirectly associated with the physical and chemical properties of the water and sediment. This study analysed the spatial and temporal distribution of Rimapenaeus constrictus in unconsolidated sublittoral sediments of two areas off the northern coast of the state of Sao Paulo, Brazil. We also analysed the association of environmental factors with the occurrence of this species. Shrimp were collected monthly from July 2001 to June 2003, with a fishing boat equipped with two double-rig nets, in the regions of Ubatuba (UBA) and Caraguatatuba (CA). The collections were made during the day, along five transects with mean depths of 5, 10, 15, 20, 25, 30, and 35 m. We obtained a total of 5478 individuals, 3403 (UBA = 2025 and CA = 1378) during the first year, and 2075 (UBA = 875 and CA = 1200) during the second year. Significant differences in abundance were observed in relation to depth, season of the year, and also in the interaction between region and depth. Higher abundances occurred in fall and winter, independently of the sampling year. The largest numbers of shrimp were caught on the 20-m transect in UBA and the 25-m transect in CA. It is concluded that the distribution pattern of this species is closely related to environmental factors, and the temperature of the bottom water and the sediment texture were the most significant variables affecting the distribution.

Musilian Concept of Modern Man

German-Austrian Robert Musil (1880-1942) is considered an artist with an extremely unorthodox conception of art to a basic human problem. In his time, there existed a dissociation of substance from social values. Musil actually started with this foundation in considering the taunting dilemma that the accelerating technology of the century is overstepping each day the ability of the human mind to adjust to it. Musil maintained that social organization, patterns of thought and cherished ideals correspond to a reality that no longer exists

Robert Cornell, Technical Editor, Electronic Technician Magazine

New York Trade School graduate Robert Cornell is pictured at his desk in his position of Technical Editor, Electronic Technician Magazine. Original caption reads "Robert Cornell - Advanced Television 1954, was appointed Technical Editor of Electronic Technician Magazine in 1956 and has served with distinction since. He is President of CETA (Certified Electronic Technicians Association), which consists of alumni of the New York Trade School who are graduates of the Advanced Television Course. He was recently invited to serve a a member of the Attorney General's Committee seeking to establish safeguards to protect the public in the field of television servicing." Black and white photograph with caption to glued to reverse.