Design of strapdown gyroscopes for a dynamic environment Semiannual report, Dec. 1967 - May 1968

Systems analysis, design, and operating characteristics of strapdown gyroscopes for dynamic environmen

Cable Rate Regulation Provisions

In October, 1992, Congress responded to consumer complaints about cable rates and services by passing the Cable Television Consumer Protection and Competition Act of 1992. The numerous provisions of the new act were the subject of two, day-long workshops held in Portland and Orono last fall that were targeted to municipal officials. The workshops were jointly sponsored by the Margaret Chase Smith Center for Public Policy, the Maine Municipal Association and the Community Television Network of Portland. Three articles in this issue are excerpted from those presentations in an effort to both communicate and explain the important changes wrought by the new cable act. In this first article, Lisa Gelb and Frederick Ellrod offer an overview of the recent changes effecting cable rate regulation

IT as a Resource for Competitive Agility: an Analysis of Firm Performance during Industry Turbulence

In an increasingly fast-paced business context, agility is crucial to firm performance. Competitive agility, the ability of a firm to rapidly sense and respond to changes in its environment, is especially important during industry turbulence. This research examines whether investment in Information Technology (IT) enhances firms’ competitive agility using analysis of firm performance during industry growth and contraction. The research approach addresses the causality question faced by previous IT productivity studies by focusing on ex-ante IT investment and subsequent firm performance during periods of unanticipated industry shocks. Findings indicate that IT investment enhances competitive agility but only in industries with unanticipated growth, calling for further investigation into the use of IT during unanticipated industry downturn

Liquid-liquid coexistence in the phase diagram of a fluid confined in fractal porous materials

Multicanonical ensemble sampling simulations have been performed to calculate the phase diagram of a Lennard-Jones fluid embedded in a fractal random matrix generated through diffusion limited cluster aggregation. The study of the system at increasing size and constant porosity shows that the results are independent from the matrix realization but not from the size effects. A gas-liquid transition shifted with respect to bulk is found. On growing the size of the system on the high density side of the gas-liquid coexistence curve it appears a second coexistence region between two liquid phases. These two phases are characterized by a different behaviour of the local density inside the interconnected porous structure at the same temperature and chemical potential.Comment: 5 pages, 4 figures. To be published in Europhys. Letter

A timeshared, runtime reconfigurable hardware co-processing architecture

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (leaves 73-74).The constant desire for increased performance in microprocessor systems has led to the need for specialized hardware cores to accelerate specific computational tasks. In this thesis, we explore the potential of using FPGA partial reconfiguration to create a platform for customized hardware cores that may be loaded on demand, at runtime, and replaced when not in use. We implement two new software tools, bitparse and bitrender, to demonstrate the bitstream relocation technique. Further, we present a functional microprocessor system coupled with a runtime reprogramable peripheral synthesized on a Xilinx Virtex-5 FPGA and discuss its performance implications.by Benjamin S. Gelb.M.Eng

A Mass Matrix for Atmospheric, Solar, and LSND Neutrino Oscillations

We construct a mass matrix for the four neutrino flavors, three active and one sterile, needed to fit oscillations in all three neutrino experiments: atmospheric, solar, and LSND, simultaneously. It organizes the neutrinos into two doublets whose central values are about 1 eV apart, and whose splittings are of the order of 10^(-3) eV. Atmospheric neutrino oscillations are described as maximal mixing within the upper doublet, and solar as the same within the lower doublet. Then LSND is a weak transition from one doublet to the other. We comment on the Majorana versus Dirac nature of the active neutrinos and show that our mass matrix can be derived from an S_2 x S_2 permutation symmetry plus an equal splitting rule.Comment: 4 pages, 0 figures, minor text change

S1 gene sequence analysis of a nephropathogenic strain of avian infectious bronchitis virus in Egypt

BACKGROUND: Infectious bronchitis is highly contagious and constitutes one of the most common and difficult poultry diseases to control. IBV is endemic in probably all countries that raise chickens. It exists as dozens of serotypes/genotypes. Only a few amino acid differences in the S1 protein of vaccine and challenge strains of IBV may result in poor protection. Tropism of IBV includes the respiratory tract tissues, proventriculus and caecal tonsils of the alimentary tract, the oviduct and the kidney. RESULTS: Infectious bronchitis virus (IBV) strain closely related to Massachusetts (Mass) serotype was isolated from broiler chickens suffering from severe renal and respiratory distresses. The isolate was serologically identified by Dot-ELISA and further characterized by RT-PCR then genotyped using S1 gene sequence analysis. Alignment of the S1 sequence of the isolate with 16 IBV strains revealed high homology to isolates related to Mass serotype. Inoculation with the strain reproduced the disease in experimental 1-day-old chickens and resulted in 20% mortality, severe renal and moderate respiratory distresses. Marked histopathological changes in both kidney and trachea were observed in experimentally infected chickens. A protection study using the H120 live attenuated vaccine showed low protection rate in spite of high S1 sequence homology (97%). Protection based criteria were: virus re-isolation attempts from trachea, tracheal and renal histopathology as well as IBV antigens detection by immunofluorescent antibody technique in kidney sections. CONCLUSION: Periodical evaluation of cross-protective capabilities of IBV vaccine(s) versus recently recovered field isolates should be performed to ensure optimum control of IBV