Study of noise reduction characteristics of double-wall panels

The noise reduction characteristics of general aviation type, flat, double-wall structures were investigated. The experimental study was carried out on 20-by-20 inch panels with an exposed area of 18 by 18 inches. A frequency range from 20 to 5000 Hz was covered. The experimental results, in general, follow the expected trends. At low frequencies the double-wall structures are no better than the single-wall structures. However, for depths normally used in the general aviation industry, the double-wall panels are very attractive. The graphite-spoxy skin panels have higher noise reduction at very low frequencies ( 100 Hz) than the Kevlar skin panels. But the aluminum panels have higher noise reduction in the high frequency region, due to their greater mass. Use of fiberglass insulation is not effective in the low frequency region, and at times it is even negative. But the insulation is effective in the high-frequency region. The theoretical model for predicting the transmission loss of these multilayered panels is also discussed

Structural motif of the DNA binding domain of γδ-resolvase characterized by affinity cleaving

The DNA binding domain of γδ-resolvase, residues 141-183, is thought to bind DNA by a helix-turn-helix motif based on sequence similarities with other known DNA binding proteins. Incorporation of the DNA cleaving moiety, EDTA Fe, at the NH2 and COOH termini of γδ(141-183) allows the positions of these residues relative to the DNA bases at three resolvase binding sites, each consisting of inverted copies of an imperfectly conserved 9-base pair sequence, to be mapped by high resolution gel electrophoresis. The cleavage data for EDTA-γδ(141-183) reveals that the NH2 terminus of the DNA binding domain of gamma delta-resolvase is bound proximal to the minor groove of DNA near the center of the resolvase binding sites. Cleavage by EDTA Fe attached to a lysine side chain (Asn^(183)→Lys^(183)) at the COOH terminus of γδ(141-183) reveals that the putative recognition helix is in the adjacent major groove on the same face of the helix, oriented toward the center of the inverted repeats

Lythraceae.

MARHOLD, K.; FELINER, G. N. (Ed.). IOPB Column

From Stakeholders to Experts: A Careful Approach to Democratizing Pharmaceuticals Policy

This paper investigates a recent FDA hearing on the popular breast cancer drug, Avastin. Using rhetorical stasis analysis, the authors demonstrate how the FDA hearing procedures exclude patient representatives from the decision-making process. The results of this study are suggestive for the development of more inclusive hybrid forums for technical decision-making

Improving Our Reference Data, or How We Killed the Hash Mark

All responsible academic libraries record their reference transactions. It is good practice to know how many patrons have been helped at your service points. For years we have participated in this record keeping with hash marks on paper, painstaking tallying, and manual spreadsheet entry for the purpose of saying, “we helped X patrons during Y month”. But, like most things academic, reference runs on its own calendar and requires more sophisticated tools to truly investigate and evaluate. To generate more useful reference statistics, we created a simple, online tool for recording reference interactions. The tool is accessible anywhere reference is taking place, generating normalized data in a centralized, backed up database. This design allows for more nuanced and granular analysis, in addition to streamlining the reporting process at a later date. Development of the tool has been iterative, soliciting feedback from primary users, including graduate students and librarians. A key part of this process was our decision to build a tool as opposed to purchasing a pre-made one. Our need to better understand our reference staffing needs was key, and a variety of commercial tools tout this ability. However, the barriers to developing such a tool in-house have dramatically lowered, making the creation of web-based tools more common. Similarly, the tool itself uses existing library infrastructure, as it is a simple web form and hooks into an existing database, so infrastructure changes were nil. With a custom-built tool, we have total control over its functionality and reporting. This presentation will discuss the full development and implementation of the new reference statistics tool, along with the data we have collected and the trends we have observed from the first six months of its use

Introduction: Governing Emergencies: Beyond Exceptionality

What characterizes emergency today is the proliferation of the term. Any event or situation supposedly has the potential to become an emergency. Emergencies may happen anywhere and at any time. They are not contained within one functional sector or one domain of life. The substantive focus of the articles collected in this special issue reflects this proliferation: they explore ways of governing in, by and through emergencies across different types of emergencies and different domains of life. In response to this proliferation, the issue opens up critical work on the politics of emergency beyond the ‘state of exception’ as dominant paradigm. Emergency is treated as a problem for government that calls for the invention of new techniques or the redeployment of existing techniques. Through this shift in emphasis, the articles in this issue disclose relations between modalities of power and emergency life that differ from the ‘lightening flash’ of a sovereign decision on the exception taken from outside of life, or the capacity to ‘mould’ an always-already emergent life from within life

Process for synthesizing enediynes

A process for synthesizing enediynes is provided. Specifically, the formed enediynes contain a hex-3-ene-1,5-diynyl group. Production of the enediynes involves adding a base to a propargylic halide in the presence of a chelating agent, which causes a carbenoid coupling-elimination sequence of the propargylic halides. A carbenoid destabilizing agent can also be added to the reaction mixture in order to enhance yield. Acyclic and cyclic enediynes can be synthesized according to this process. The enediynes are useful compounds that can be used in a variety of applications including use in the production of anti-tumor agents

The Structure of High Strehl Ratio Point-Spread Functions

We describe the symmetries present in the point-spread function (PSF) of an optical system either located in space or corrected by an adaptive o to Strehl ratios of about 70% and higher. We present a formalism for expanding the PSF to arbitrary order in terms of powers of the Fourier transform of the residual phase error, over an arbitrarily shaped and apodized entrance aperture. For traditional unapodized apertures at high Strehl ratios, bright speckles pinned to the bright Airy rings are part of an antisymmetric perturbation of the perfect PSF, arising from the term that is first order in the residual phase error. There are two symmetric second degree terms. One is negative at the center, and, like the first order term, is modulated by the perfect image's field strength -- it reduces to the Marechal approximation at the center of the PSF. The other is non-negative everywhere, zero at the image center, and can be responsible for an extended halo -- which limits the dynamic range of faint companion detection in the darkest portions of the image. In regimes where one or the other term dominates the speckles in an image, the symmetry of the dominant term can be exploited to reduce the effect of those speckles, potentially by an order of magnitude or more. We demonstrate the effects of both secondary obscuration and pupil apodization on the structure of residual speckles, and discuss how these symmetries can be exploited by appropriate telescope and instrument design, observing strategies, and filter bandwidths to improve the dynamic range of high dynamic range AO and space-based observations. Finally, we show that our analysis is relevant to high dynamic range coronagraphy.Comment: Accepted for publication in ApJ; 20 pages, 4 figure

System Size Stochastic Resonance: General Nonequilibrium Potential Framework

We study the phenomenon of system size stochastic resonance within the nonequilibrium potential's framework. We analyze three different cases of spatially extended systems, exploiting the knowledge of their nonequilibrium potential, showing that through the analysis of that potential we can obtain a clear physical interpretation of this phenomenon in wide classes of extended systems. Depending on the characteristics of the system, the phenomenon results to be associated to a breaking of the symmetry of the nonequilibrium potential or to a deepening of the potential minima yielding an effective scaling of the noise intensity with the system size.Comment: LaTex, 24 pages and 9 figures, submitted to Phys. Rev.