It is shown that for four-transmitter systems, a family of four-by-four unit-rate complex quasi-orthogonal space–time block codes, where each entry equals a symbol variable up to a change of sign and/or complex conjugation, can be generated from any two independent codes via elementary operations. The two independent groups of codes in the family generally have different properties of diversity...

Approximately 7000 marine zooplanktonic species have been described so far for the World Ocean; in the South Atlantic the presence of 40% of these has been confirmed, and an additional 20–30% are expected to be recorded in the future. The overall number of described species is very low when compared with other communities, and yet it may not be too far from the final, complete inventory. Very a...

Punctuated antigenic change is believed to be a key element in the evolution of influenza A; clusters of antigenically similar strains predominate worldwide for several years until an antigenically distant mutant emerges and instigates a selective sweep. It is thought that a region of East-Southeast Asia with year-round transmission acts as a source of antigenic diversity for influenza A and se...

Considerable interest is currently focused on fish haemoglobins in order to identify the structural basis for their diversity of functional behaviour. The armored catfish Liposarcus anisitsi presents accessorial air breathing through a modified stomach, which allows this species to survive in waters with low oxygen content. The analysis of its haemolysate has shown the presence of four main hae...

Haemoglobin is the iron-containing oxygen-transport metalloprotein that is present in the red blood cells of all vertebrates. In recent decades, there has been substantial interest in attempting to understand the structural basis and functional diversity of avian haemoglobins. Towards this end, purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies have b...

Scale-dependence is a well-known phenomenon in geography with sophisticated theoretical approaches and techniques at hand to deal with the modifiable areal unit problem (MAUP). Geographical analyses are, however, predominantly focusing on urban spaces with a high level of small-scaled social diversity. While space is considered scale-sensitive less attention is paid to scale in a temporal and s...

This study focused on the diversity of bacterial communities from two series of two-stage constructed wetlands (CWs) treating tannery wastewater, under different hydraulic conditions. Series were separately planted with Typha latifolia and Phragmites australis in expanded clay aggregates and operated for 31 months. The effect of plant species, hydraulic loading and unit stage on bacterial commu...