Local measurements of velocity fluctuations and diffusion coefficients for a granular material flow

Measurements were made of two components of the average and fluctuating velocities, and of the local self-diffusion coefficients in a flow of granular material. The experiments were performed in a 1 m-high vertical channel with roughened sidewalls and with polished glass plates at the front and the back to create a two-dimensional flow. The particles used were glass spheres with a nominal diameter of 3 mm. The flows were high density and were characterized by the presence of long-duration frictional contacts between particles. The velocity measurements indicated that the flows consisted of a central uniform regime and a shear regime close to the walls. The fluctuating velocities in the transverse direction increased in magnitude from the centre towards the walls. A similar variation was not observed for the streamwise fluctuations. The self-diffusion coefficients showed a significant dependence on the fluctuating velocities and the shear rate. The velocity fluctuations were highly anistropic with the streamwise components being 2 to 2.5 times the transverse components. The self-diffusion coefficients for the streamwise direction were an order-of-magnitude higher than those for the transverse direction. The surface roughness of the particles led to a decrease in the self-diffusion coefficients

On the breeding habits of the Cowry Erronea errones (Linne)

Cowries are fairly common in the shallow a reas of Palk Bay and Gulf of Mannar. The species commonly found in the area between Mandapam Camp and Mandapam has been ide ntified as Erronea errones (Linne

Studies on the egg masses and larval development of some Prosobranchs from the Gulf of Mannar and the Palk Bay

In recent years our knowledge of the eggs and larvae of marine gastropods has increased considerably. The investigations of Lebour (1937) and Thorson (1946) have added much to our knowledge of the eggs and larvae of prosobranchs from Plymouth and Danish waters. Francis (1948) investigations at Algiers and Banyuls supplement at many points the work of Lebour and Thorson

Fluorescent Plasmodium berghei sporozoites and pre-erythrocytic stages: a new tool to study mosquito and mammalian host interactions with malaria parasites.

To track malaria parasites for biological studies within the mosquito and mammalian hosts, we constructed a stably transformed clonal line of Plasmodium berghei, PbFluspo, in which sporogonic and pre-erythrocytic liver-stage parasites are autonomously fluorescent. A cassette containing the structural gene for the FACS-adapted green fluorescent protein mutant 2 (GFPmut2), expressed from the 5' and 3' flanking sequences of the circumsporozoite (CS) protein gene, was integrated and expressed at the endogenous CS locus. Recombinant parasites, which bear a wild-type copy of CS, generated highly fluorescent oocysts and sporozoites that invaded mosquito salivary glands and were transmitted normally to rodent hosts. The parasites infected cultured hepatocytes in vitro, where they developed into fluorescent pre-erythrocytic forms. Mammalian cells infected by these parasites can be separated from non-infected cells by fluorescence activated cell sorter (FACS) analysis. These fluorescent insect and mammalian stages of P. berghei should be useful for phenotypic studies in their respective hosts, as well as for identification of new genes expressed in these parasite stages