Integral equation formulation for buoyancy-driven convection problems

An integral equation formulation for buoyancy-driven convection problems is developed and illustrated. Buoyancy-driven convection in a bounded cylindrical geometry with a free surface is studied for a range of aspect ratios and Nusselt numbers. The critical Rayleigh number, the nature of the cellular motion, and the heat transfer enhancement are computed using linear theory. Green's functions are used to convert the linear problem into linear Fredholm integral equations. Theorems are proved which establish the properties of the eigenvalues and eigenfunctions of the linear integral operator which appears in these equations.     

Permanently oriented antibody immobilization for digoxin determination with a flow-through fluoroimmunosensor

This paper reports a new flow-through fluoroimmunosensor, the function of which is based on antibodies immobilized on an inmunoreactor of controlled-pore glass (CPG), for determination of digoxin, used in the treatment of congestive heart failure and artery disease. The immunosensor has a detection limit of 1.20 microg L(-1) and provides high reproducibility (RSD=4.5% for a concentration of 0.0025 mg L(-1), and RSD=6.7% for 0.01 mg L(-1)). The optimum working concentration range was found to be 1.2 x 10(-3)-4.0 x 10(-2) mg L(-1). The lifetime of the immunosensor was about 50 immunoassays; if stored unused its lifetime can be extended to three months. A sample speed of about 10-12 samples per hour can be attained. Possible interference from substances with structures similar to digoxin (morphine, heroin, tebaine, codeine, pentazocine and narcotine) was investigated. No cross-reactivity was seen at the highest digoxin: interferent ratio studied (1:100). The proposed fluoroimmunosensor was successfully used to determine digoxin concentrations in human serum samples.     

Investing in the stock market: Statistical pooling of individual preference judgments

Literature concerning the quality of individual and face-to-face group judgments has generally concluded that both groups and statistically pooled individuals outperform randomly chosen or average individuals. This paper extends previous research by comparing statistically pooled individual judgments of both individuals and face-to-face groups in a stock selection task. In general, decisions that would have resulted from statistically pooled judgments were better (as assessed by future stock value) than those that would have resulted from individual or face-to-face group judgments. In choosing among pooling methods, majority rule is often thought to be a very compelling criterion. However, majority rule can produce intransitive group preferences. Methods that use some procedure to resolve the intransitivities of majority rule did not perform well relative to other non-majority rule based methods. Another class of pooling methods, termed equity methods, used in conjunction with ordinal judgments, are recommended based on simplicity, performance, and fairness criteria. The results are discussed in terms of the nature of the task.