Modern Frontiers

The most common grievance of our generation is that of the lack of frontiers. Our forefathers had unknown lands to develop, unknown oceans to cross, and unknown lands to civilize. Our complaint is that everything worth doing has already been done. With few exceptions, the whole world has been explored and settled and more or less civilized; our oceans have been charted; our industries have been highly developed. Where do we go now

Computer Applications To Book Catalogs And Library Systems

Librarians must look to the future information needs of a country expanding in population, technology and educational requirements. The "information explosion" is placing an additional strain on existing methods of providing information rapidly and economically. A library seeking to develop a modern information retrieval program has many existing services from which to choose. The problem is to define the program that will best serve the present library users and leave room for flexible action in the future, and then to pick a combination of services that best match these objectives. Documentation Incorporated (Doc Inc) of Bethesda, Maryland, was founded in 1952 by the late Dr. Mortimer Taube, and has been engaged in developing modern information retrieval systems for government and industry. A key concept that is now emerging is the development of mechanized or computerized data banks. This data bank concept is a plan for organizing a single set of data for producing many products. The traditional library card catalog or data bank, long the key to finding materials in the nation's libraries, today is getting competition from book catalogs. Using data bank techniques to keep a library catalog updated, Doc Inc computer systems generate printouts of the catalog which are used to produce bound books for distribution to library users. In effect, the book catalogs are carrying the traditional card catalog, literally, into the homes and offices of users instead of requiring them to trek to the library to find out if the information they want is available. The computer is used to produce several indexes (such as subject, author, and title) in various formats from a single file of data and is particularly effective if the catalog data bank is standardized.published or submitted for publicatio

Why Write Statistical Software? The Case of Robust Statistical Methods

Robust statistical methods are designed to work well when classical assumptions, typically normality and/or the lack of outliers, are violated. Almost everyone agrees on the value of robust statistical procedures. Nonetheless, after more than 40 years and thousands of papers, few robust methods were available in standard statistical software packages until very recently. This paper argues that one of the primary reasons for the lack of robust statistical methods in standard statistical software packages is the fact that few developers of statistical methods are willing to write user-friendly and readable software for the methods they develop, regardless of the usefulness of the method. Recent changes in academic statistics make it highly desirable for all developers of statistical methods to provide usable code for their statistical methods.

Characteristics, Contracts, and Actions: Evidence from Venture Capitalist Analyses

We study the investment analyses of 67 portfolio investments by 11 venture capital (VC) firms. VCs consider the attractiveness and risks of the business, management, and deal terms as well as expected post-investment monitoring. We then consider the relation of the analyses to the contractual terms. Greater internal and external risks are associated with more VC cash flow rights, VC control rights; greater internal risk, also with more contingencies for the entrepreneur; and greater complexity, with less contingent compensation. Finally, expected VC monitoring and support are related to the contracts. We interpret these results in relation to financial contracting theories.

An Atom Laser is not monochromatic

We study both numerically and analytically the possibility of using an adiabatic passage control method to construct a Mach-Zehnder interferometer (MZI) for Bose-Einstein condensates (BECs) in the time domain, in exact one-to-one correspondence with the traditional optical MZI that involves two beam splitters and two mirrors. The interference fringes one obtains from such a minimum-disturbance set up clearly demonstrates that, fundamentally, an atom laser is not monochromatic due to interatomic interactions. We also consider how the amount of entanglement in the system correlates to the interference fringes.Comment: 4 figures. Submitted for publicatio

Financial Contracting Theory Meets the Real World: An Empirical Analysis of Venture Capital Contracts

In this paper, we compare the characteristics of real world financial contracts to their counterparts in financial contracting theory. We do so by conducting a detailed study of actual contracts between venture capitalists (VCs) and entrepreneurs. We consider VCs to be the real world entities who most closely approximate the investors of theory. (1) The distinguishing characteristic of VC financings is that they allow VCs to separately allocate cash flow rights, voting rights, board rights, liquidation rights, and other control rights. We explicitly measure and report the allocation of these rights. (2) While convertible securities are used most frequently, VCs also implement a similar allocation of rights using combinations of multiple classes of common stock and straight preferred stock. (3) Cash flow rights, voting rights, control rights, and future financings are frequently contingent on observable measures of financial and non-financial performance. (4) If the company performs poorly, the VCs obtain full control. As company performance improves, the entrepreneur retains / obtains more control rights. If the company performs very well, the VCs retain their cash flow rights, but relinquish most of their control and liquidation rights. The entrepreneur's cash flow rights also increase with firm performance. (5) It is common for VCs to include non-compete and vesting provisions aimed at mitigating the potential hold-up problem between the entrepreneur and the investor. We interpret our results in relation to existing financial contracting theories. The contracts we observe are most consistent with the theoretical work of Aghion and Bolton (1992) and Dewatripont and Tirole (1994). They also are consistent with screening theories.

JT9D performance deterioration results from a simulated aerodynamic load test

The results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance are presented. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt & Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts

JT9D jet engine diagnostics program

Performance deterioration in the JT9D-7 is a flight sensitive phenomenon caused by one short term and two long term wear modes. The short term deterioration occurs primarily during airplane acceptance testing and therefore does not affect airline operation. The long term wear takes place continuously over the engine life so that the performance loss can be minimized by a sound maintenance program. Short term deterioration is primarily due to flight load induced blade and gas path seal wear which result in increased gas path running clearances. The wear occurs in all engine modules but has the most deleterious effect on the low pressure compressor and high pressure turbine performance. The wear occurs during conditions that combine minimum axisymmetric running clearances and maximum engine distortion or asymmetric closure

Is There an App for That? Electronic Health Records (EHRs) and a New Environment of Conflict Prevention and Resolution

Katsh discusses the new problems that are a consequence of a new technological environment in healthcare, one that has an array of elements that makes the emergence of disputes likely. Novel uses of technology have already addressed both the problem and its source in other contexts, such as e-commerce, where large numbers of transactions have generated large numbers of disputes. If technology-supported healthcare is to improve the field of medicine, a similar effort at dispute prevention and resolution will be necessary