GI LB E RT . 1998. Differences in opacity between wells of a microtitre plate containing different volumes of inoculated growth medium reflected planktonic growth without any contribution from cells attached at the well surface. Simple algebra and a knowledge of the dependence of optical density upon sample path length (volume) for suspensions of differing cell density enables the generation of growth curves for attached populations (biofilms). In this manner, minimum inhibitory concentrations (MICs) were determined at various stages of growth (0-20 h), both for cells growing attached to the bases of the plate wells and, simultaneously, for cells growing in suspension above them. Biocides included cetrimide, polyhexamethylene biguanide, peracetic acid, phenoxyethanol and chloroxylenol. Results, expressed as planktonic:biofilm MIC ratios, showed susceptibility to change, not only as a function of attachment and biofilm formation, but also with respect to the nature of the chemical agent. In some instances, changes in susceptibility greater than twofold occurred immediately on attachment and could occur in the presence of biocide concentrations which exceeded the MIC.

The effect of pretreatment on the Cd 2+ biosorption capacity of mycelial biomass of Pleurotus florida was investigated. For this purpose, the biomass was subjected to physical treatments such as heat, autoclaving and freeze drying and chemical treatments using acids, alkali and organic solvents. All the pretreatment methods improved the biosorption of Cd 2+ in comparison with live biomass of P. florida. Among physical treatments, freeze drying showed significant improvement in Cd 2+ sorption capacity. Pretreatment of biomass with NaOH showed maximum cadmium biosorption followed by formaldehyde and methanol treatment.

Most probable number (MPN) test was done to detect the coliform in water samples collected from mobile vendors, sweet shops and tap water supplied from Burdwan municipality. The study revealed that the number of coliforms was very high ( 1600) in water samples collected from mobile vendors. The bacteria were identified as Escherichia coli. Bacteriological examination of water samples collected from different sources showed that the water of mobile vendors and sweet shops of Burdwan market area was not potable while the municipal tap water was found to be safe for drinking.

This paper looks at the private schooling sector in Pakistan, a country that is seriously behind schedule in achieving the Millennium Development Goals. Using new data, we document the phenomenal rise of the private sector in Pakistan and show that an increasing segment of children enrolled in private schools are from rural areas and from middle-class and poorer families. The key element in their rise is their low fees--the average fee of a rural private school in Pakistan is less than a dime a day (Rs.6)! They hire predominantly local, female and moderately educated teachers who have limited alternative opportunities outside the village. Hiring these teachers at low cost allows the savings to be passed on to parents through very low fees. This mechanism-the need to hire teachers with a certain demographic profile so that salary costs are minimized-defines the possibility of private schools-where they arise, fees are low. It also defines their limits. Private schools are horizontally constrained in that they arise in villages where there is a pool of secondaryeducated women. They are also vertically constrained in that they are unlikely to cater to the secondary levels in rural areas, at least until there is an increase in the supply of potential teachers with the required skills and educational levels.

The monoclonal antibody 7E12H12 can differentiate primary adenocarcinoma of the bladder from secondary adenocarcinoma arising in the prostate and may be a useful tool in diagnostic pathology.