The effects of centrifuge radius on the performance of entry tasks

Effects of centrifuge radius on entry task performance - discrete response task, tracking task, and transfer of training effect

Development of nine-channel 10-micrometer (Hg, Cd)Te pushbroom IR/CCD system

The engineering development of the 9-channel detector array is documented. The development of the array demonstrates the feasibility of a self scanned multi-element infrared detector focal plane. Procedures for operating the array are outlined

Compressing DNA sequence databases with coil

Background: Publicly available DNA sequence databases such as GenBank are large, and are growing at an exponential rate. The sheer volume of data being dealt with presents serious storage and data communications problems. Currently, sequence data is usually kept in large "flat files," which are then compressed using standard Lempel-Ziv (gzip) compression – an approach which rarely achieves good compression ratios. While much research has been done on compressing individual DNA sequences, surprisingly little has focused on the compression of entire databases of such sequences. In this study we introduce the sequence database compression software coil. Results: We have designed and implemented a portable software package, coil, for compressing and decompressing DNA sequence databases based on the idea of edit-tree coding. coil is geared towards achieving high compression ratios at the expense of execution time and memory usage during compression – the compression time represents a "one-off investment" whose cost is quickly amortised if the resulting compressed file is transmitted many times. Decompression requires little memory and is extremely fast. We demonstrate a 5% improvement in compression ratio over state-of-the-art general-purpose compression tools for a large GenBank database file containing Expressed Sequence Tag (EST) data. Finally, coil can efficiently encode incremental additions to a sequence database. Conclusion: coil presents a compelling alternative to conventional compression of flat files for the storage and distribution of DNA sequence databases having a narrow distribution of sequence lengths, such as EST data. Increasing compression levels for databases having a wide distribution of sequence lengths is a direction for future work

A dual telescope for spectroheliography in the extreme ultra-violet

Dual reflecting telescope design for ultraviolet spectroheliograph

Application of steady state finite element and transient finite difference theory to sound propagation in a variable area duct: A comparison with experiment

Sound propagation without flow in a rectangular duct with a converging-diverging area variation was studied experimentally and theoretically. The area variation was of sufficient magnitude to produce large reflections and induce modal scattering. The rms (root-mean-squared) pressure and phase angle on both the flat and curved surface were measured and tabulated. The steady state finite element theory and the transient finite difference theory are in good agreement with the data. It is concluded that numerical finite difference and finite element theories appear ideally suited for handling duct propagation problems which encounter large area variations

Technological change, financial innovation, and diffusion in banking

This paper discusses the technological change and financial innovation that commercial banking has experienced during the past twenty-five years. The paper first describes the role of the financial system in economies and how technological change and financial innovation can improve social welfare. We then survey the literature relating to several specific financial innovations, which we define as new products or services, production processes, or organizational forms. We find that the past quarter century has been a period of substantial change in terms of banking products, services, and production technologies. Moreover, while much effort has been devoted to understanding the characteristics of users and adopters of financial innovations and the attendant welfare implications, we still know little about how and why financial innovations are initially developed.Technological innovations

Fussing and fuming over Fannie and Freddie: how much smoke, how much fire?

The roles of Fannie Mae and Freddie Mac have become increasingly controversial in the modern world of residential mortgage finance. The authors describe the special features of these two companies and their roles in the mortgage markets and then discuss the controversies that surround the companies and offer recommendations for improvements in public policy.

Some integration formulae which simplify the evaluation of certain integrals in common use by engineers

Integration formulas to simplify evaluation of certain commonly used integral

Emerging competition and risk-taking incentives at Fannie Mae and Freddie Mac

This paper examines two major forces that may soon increase competition in the U.S. secondary conforming mortgage market: (1) the expansion of Federal Home Loan Bank mortgage purchase programs and (2) the adoption of revised risk-based capital requirements for large U.S. banks (Basel II). The authors argue that this competition is likely to reduce the growth and relative importance of Fannie Mae and Freddie Mac and hence their franchise values and effective capital. Such developments could, in turn, lead to more risky behaviors by these two GSEs. It is this last consequence that warrants greater regulatory awareness.