There is no MacWilliams identity for convolutional codes

An example is provided of two convolutional codes that have the same transmission gain but whose dual codes do not. This shows that no analog of the MacWilliams identity for block codes can exist relating the transmission gains of a convolutional code and its dual

Measuring Disparate Impacts and Extending Disparate Impact Doctrine to Organ Transplantation

This paper examines the economic and statistical foundations of proposed tests for discrimination. We focus on extension of disparate impact doctrine to new domains.

Overview and evolution of the LeRC PMAD DC Testbed

Since the beginning of the Space Station Freedom Program (SSFP), the Lewis Research Center (LeRC) has been developed electrical power system test beds to support the overall design effort. Through this time, the SSFP has changed the design baseline numerous times, however, the test bed effort has endeavored to track these changes. Beginning in August 1989 with the baseline and an all DC system, a test bed was developed to support the design baseline. The LeRC power measurement and distribution (PMAD) DC test bed and the changes in the restructure are described. The changes includeed the size reduction of primary power channel and various power processing elements. A substantial reduction was also made in the amount of flight software with the subsequent migration of these functions to ground control centers. The impact of these changes on the design of the power hardware, the controller algorithms, the control software, and a description of their current status is presented. An overview of the testing using the test bed is described, which includes investigation of stability and source impedance, primary and secondary fault protection, and performance of a rotary utility transfer device. Finally, information is presented on the evolution of the test bed to support the verification and operational phases of the SSFP in light of these restructure scrubs

Monetarist Interpretations of the Great Depression: An Evaluation and Critique

This paper rejects the proposition that there is only a single interesting question to ask about the decade of the 1930s. It is concerned not only with the role of money in the 1929-33 contraction but also with the relative role of monetary and nonmonetary factors in the recession of 1937-38 and subsequent recovery and, in addition, with the division of nominal income change between prices and real output. New empirical evidence bearing on each of these issues is provided The results suggest that both extreme monetarist and nonmonetarist interpretations of the decade of the l930s are unsatisfactory and leave interesting features of the data unexplained. Arguing against acceptance of an extreme monetarist interpretation are (1) the inability of changes in the money supply alone to explain the severity of the initial collapse in income between 1929 and the fall of 1931, (2) the steady weakening of the correlation between changes in nominal income and money as the 1930s progressed, (3) the failure of monetary factors to explain the nature and timing of the 1938-41 recovery, and (4) the apparent absence of any tendency for the mechanism of price flexibility to provide strong self-correcting forces as required by an approach that stresses monetary rules and opposes policy activism. Arguing against acceptance of an extreme nonmonetarist interpretation are (1) the close association between the collapse in income and the lagged effect of monetary changes after the fall of 1931, (2) the milder contraction and earlier recoveries associated with the more expansive monetary policies pursued in Europe, (3) the close association between money and income in the 1937-38 recession, and (4) the failure of the price change data to adhere to the expectational Phillips curve approach imbedded in many postwar econometric models constructed by nonmonetarists.

Auxin-induced growth inhibition a natural consequence of two-point attachment

It is characteristic of a great number of biologically active substances that the responses which they elicit are twofold, low concentrations of the material promoting a particular activity, and higher concentrations inhibiting it. This is the case with the auxin-induced growth responses of plants. An active auxin such as indole acetic acid (IAA) brings about and is essential to growth in length of stems, hypocotyls and other plant organs including the Avena coleoptile

Description of economic data collected with a random sample of commercial reef fish boats in the Florida Keys

This study summarizes the results of a survey designed to provide economic information about the financial status of commercial reef fish boats with homeports in the Florida Keys. A survey questionnaire was administered in the summer and fall of 1994 by interviewers in face-to-face meetings with owners or operators of randomly selected boats. Fishermen were asked for background information about themselves and their boats, their capital investments in boats and equipment, and about their average catches, revenues, and costs per trip for their two most important kinds of fishing trips during 1993 for species in the reef fish fishery. Respondents were characterized with regard to their dependence on the reef fish fishery as a source of household income. Boats were described in terms of their physical and financial characteristics. Different kinds of fishing trips were identified by the species that generated the greatest revenue. Trips were grouped into the following categories: yellowtail snapper (Ocyurus chrysurus); mutton snapper (Lutjanus analis), black grouper (Mycteroperca bonaci), or red grouper (Epinephelus morio); gray snapper (Lutjanus griseus); deeper water groupers and tilefishes; greater amberjack (Seriola dumerili); spiny lobster (Panulirus argus); king mackerel (Scomberomorus cavalla); and dolphin (Coryphaena hippurus). Average catches, revenues, routine trip costs, and net operating revenues per boat per trip and per boat per year were estimated for each category of fishing trips. In addition to its descriptive value, data collected during this study will aid in future examinations of the economic effects of various regulations on commercial reef fish fishermen.(PDF file contains 48 pages.

A circumpolar perspective on fluvial sediment flux to the Arctic ocean

Quantification of sediment fluxes from rivers is fundamental to understanding land‐ocean linkages in the Arctic. Numerous publications have focused on this subject over the past century, yet assessments of temporal trends are scarce and consensus on contemporary fluxes is lacking. Published estimates vary widely, but often provide little accessory information needed to interpret the differences. We present a pan‐arctic synthesis of sediment flux from 19 arctic rivers, primarily focusing on contributions from the eight largest ones. For this synthesis, historical records and recent unpublished data were compiled from Russian, Canadian, and United States sources. Evaluation of these data revealed no long‐term trends in sediment flux, but did show stepwise changes in the historical records of two of the rivers. In some cases, old values that do not reflect contemporary fluxes are still being reported, while in other cases, typographical errors have been propagated into the recent literature. Most of the discrepancy among published estimates, however, can be explained by differences in years of records examined and gauging stations used. Variations in sediment flux from year to year in arctic rivers are large, so estimates based on relatively few years can differ substantially. To determine best contemporary estimates of sediment flux for the eight largest arctic rivers, we used a combination of newly available data, historical records, and literature values. These estimates contribute to our understanding of carbon, nutrient, and contaminant transport to the Arctic Ocean and provide a baseline for detecting future anthropogenic or natural change in the Arctic