a b s t r a c tThis paper provides parametric estimates of technical change, efficiency change, economies of scale, and total factor productivity growth for large banks (those with assets in excess of $1 billion) in the United States, over the period from 2000 to 2005. This is done by estimating an output distance function subject to theoretical regularity within a Bayesian framework. We find that failure to incorporate theoretical regularity conditions results in mismeasured shadow revenue and/or cost shares, which in turn leads to perverse conclusions regarding productivity growth. Our results from the regularity-constrained model show that total factor productivity of the large US banks grew at an average rate of 1.98% over the sample period. However, our estimates also show a clear downward trend in the growth rate of total factor productivity and our decomposition of the primal Divisia total factor productivity growth index into its three components -technical change, efficiency change, and economies of scale -indicates that technical change is the driving force behind this decline.

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SUMMARYThis paper provides estimates of bank efficiency and productivity in the United States, over the period from 1998 to 2005, using (for the first time) the globally flexible Fourier cost functional form, as originally proposed by Gallant (1982), and estimated subject to global theoretical regularity conditions, using procedures suggested by Gallant and Golub (1984). We find that failure to incorporate monotonicity and curvature into the estimation results in mismeasured magnitudes of cost efficiency and misleading rankings of individual banks in terms of cost efficiency. We also find that the largest two subgroups (with assets greater than 1 billion in 1998 dollars) are less efficient than the other subgroups and that the largest four bank subgroups (with assets greater than $400 million) experienced significant productivity gains and the smallest eight subgroups experienced insignificant productivity gains or even productivity losses.

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This paper describes a micropump composed of a piezoelectric PZT unimorph and one-way parylene valves. Two different designs of the valves (cantilever-and bridge-type) are studied, fabricated and tested. The micropump (13 × 13 × 1.2 mm 3 in size) is capable of pumping liquid up to 700 µL min −1 with its pumping speed being insensitive to a backpressure up to 2.5 kPa. The flow rate of 700 µL min −1 is obtained when the micropump is driven with square pulses at 6 kHz with 50% duty cycle and 100 V peak-to-peak. The maximum static pumping pressure is measured to be 4 kPa.