9,556 research outputs found
Flexible blade antenna Patent
Flexible monopole antenna with broad bandwidth and low voltage standing wave rati
Shuttle orbiter S-band quad antenna switching evaluation
Automatic switching of the shuttle orbiter S-band quad antennas by the orbiter on-board computers was evaluated. The development and use of an extensive computer program to determine antenna switch position states as a function of time for various orbital activities is described. The selection of the optimum quad antenna element at any given time is based on the look angle to the appropriate Tracking Data Relay Satellite (TDRS). It is shown that a 2.4 second period is required for updating the S-band quad antenna switch state based on a maximum roll rate of 2 deg per second. The possibility of a variable update period is suggested since the 2 deg per second attitude rate is seldom encountered and would, for example, dictate approximately 248,000 on-board computer calculations during Reference Mission 2. The average number of antenna switch state changes was found to be in the range of 1,300 for Reference Mission 2
Infrared continuum observations of the solar atmosphere
The far-infrared wavelengths (10 microns to 1 mm) were used to study the spatial and temporal structure of the solar atmosphere. Observational results were obtained on flares, faculae, sunspots, and on the center-to-limb intensity distribution, as well as on time variability within these regions. A program of precise monitoring of slow variations in the integrated solar luminosity was shown to be feasible, and initial steps to implement observations were completed
The reform of october 1979: how it happened and why
This study offers a historical review of the monetary policy reform of October 6, 1979, and discusses the influences behind it and its significance. We lay out the record from the start of 1979 through the spring of 1980, relying almost exclusively upon contemporaneous sources, including the recently released transcripts of Federal Open Market Committee (FOMC) meetings during 1979. We then present and discuss in detail the reasons for the FOMC's adoption of the reform and the communications challenge presented to the Committee during this period. Further, we examine whether the essential characteristics of the reform were consistent with monetarism, new, neo, or old-fashioned Keynesianism, nominal income targeting, and inflation targeting. The record suggests that the reform was adopted when the FOMC became convinced that its earlier gradualist strategy using finely tuned interest rate moves had proved inadequate for fighting inflation and reversing inflation expectations. The new plan had to break dramatically with established practice, allow for the possibility of substantial increases in short-term interest rates, yet be politically acceptable, and convince financial markets participants that it would be effective. The new operating procedures were also adopted for the pragmatic reason that they would likely succeed. JEL Klassifikation: E52, E58, E61, E65
Support for Instructional Leadership: Supervision, Mentoring, and Professional Development for U.S. School Leaders - Findings from the American School Leader Panel
With school leadership second only to teaching among school-related influences on student learning, principals can play an important role in school success. But how do their districts promote their effectiveness, especially in improving teaching? Based on a survey of the American School Leader Panel, a representative sample of principals from across the United States, this report explores the prevalence and quality of three important on-the-job supports for school leaders: supervision, mentorship and professional development (as defined by at least a day focused on principals). The good news is that two-thirds of principals report receiving some support. The bad news is that more than two thirds (68 percent) report that they don't receive all three sources of help. Mentoring, for example, is typically available only to first- or second-year principals or those encountering difficulties on the job, and only a minority of principals report that their districts require mentoring, even for first-year (49 percent of respondents) or struggling principals (21 percent). Also, the prevalence of support a principal receives may depend on the size of his or her school district. Both mentoring and professional development are more readily available in larger and medium-sized districts than smaller ones. The value principals place on the support they receive is linked to whether the support emphasizes the key aspect of principals' job—improving teachers' instruction. For example, all of the principals (100 percent) who reported that their mentors focused on instruction to a great extent also said that they prized the mentoring. That compares with a minority (40 percent) of principals who said their mentors devoted little to no time to instruction
Comparative Genomics of a Parthenogenesis-Inducing Wolbachia Symbiont.
Wolbachia is an intracellular symbiont of invertebrates responsible for inducing a wide variety of phenotypes in its host. These host-Wolbachia relationships span the continuum from reproductive parasitism to obligate mutualism, and provide a unique system to study genomic changes associated with the evolution of symbiosis. We present the genome sequence from a parthenogenesis-inducing Wolbachia strain (wTpre) infecting the minute parasitoid wasp Trichogramma pretiosum The wTpre genome is the most complete parthenogenesis-inducing Wolbachia genome available to date. We used comparative genomics across 16 Wolbachia strains, representing five supergroups, to identify a core Wolbachia genome of 496 sets of orthologous genes. Only 14 of these sets are unique to Wolbachia when compared to other bacteria from the Rickettsiales. We show that the B supergroup of Wolbachia, of which wTpre is a member, contains a significantly higher number of ankyrin repeat-containing genes than other supergroups. In the wTpre genome, there is evidence for truncation of the protein coding sequences in 20% of ORFs, mostly as a result of frameshift mutations. The wTpre strain represents a conversion from cytoplasmic incompatibility to a parthenogenesis-inducing lifestyle, and is required for reproduction in the Trichogramma host it infects. We hypothesize that the large number of coding frame truncations has accompanied the change in reproductive mode of the wTpre strain
ChromaStarPy: A stellar atmosphere and spectrum modeling and visualization lab in python
We announce ChromaStarPy, an integrated general stellar atmospheric modeling
and spectrum synthesis code written entirely in python V. 3. ChromaStarPy is a
direct port of the ChromaStarServer (CSServ) Java modeling code described in
earlier papers in this series, and many of the associated JavaScript (JS)
post-processing procedures have been ported and incorporated into CSPy so that
students have access to ready-made "data products". A python integrated
development environment (IDE) allows a student in a more advanced course to
experiment with the code and to graphically visualize intermediate and final
results, ad hoc, as they are running it. CSPy allows students and researchers
to compare modeled to observed spectra in the same IDE in which they are
processing observational data, while having complete control over the stellar
parameters affecting the synthetic spectra. We also take the opportunity to
describe improvements that have been made to the related codes, ChromaStar
(CS), CSServ and ChromaStarDB (CSDB) that, where relevant, have also been
incorporated into CSPy. The application may be found at the home page of the
OpenStars project: http://www.ap.smu.ca/~ishort/OpenStars/ .Comment: See DOI zenodo.1095687. Accepted for publication in The Astrophysical
Journa
The reform of October 1979: how it happened and why
This study offers a historical review of the monetary policy reform of October 6, 1979, and discusses the influences behind it and its significance. We lay out the record from the start of 1979 through the spring of 1980, relying almost exclusively upon contemporaneous sources, including the recently released transcripts of Federal Open Market Committee (FOMC) meetings during 1979. We then present and discuss in detail the reasons for the FOMC's adoption of the reform and the communications challenge presented to the Committee during this period. Further, we examine whether the essential characteristics of the reform were consistent with monetarism, new, neo, or old-fashioned Keynesianism, nominal income targeting, and inflation targeting. The record suggests that the reform was adopted when the FOMC became convinced that its earlier gradualist strategy using finely tuned interest rate moves had proved inadequate for fighting inflation and reversing inflation expectations. The new plan had to break dramatically with established practice, allow for the possibility of substantial increases in short-term interest rates, yet be politically acceptable, and convince financial markets participants that it would be effective. The new operating procedures were also adopted for the pragmatic reason that they would likely succeed.Monetary policy ; Federal Reserve System - History
The NASA teleconferencing system: An evaluation
The communication requirements of the Apollo project led to the development of a teleconferencing network which linked together, in an audio-fax mode, the several NASA centers and supporting contractors of the Apollo project. The usefulness of this communication linkage for the Apollo project suggested that the system might be extended to include all NASA centers, enabling them to conduct their in-house business more efficiently than by traveling to other centers. A pilot project was run in which seventeen NASA center and subcenters, some with multiple facilities, were connected into the NASA teleconferencing network. During that year, costs were charted and, at the end of the year, an evaluation was made to determine how the system had been used and with what results. The year-end evaluation of the use of NASA teleconferencing system is summarized
The reform of October 1979: how it happened and why
This study offers a historical review of the monetary policy reform of October 6, 1979, and discusses the influences behind it and its significance. We lay out the record from the start of 1979 through the spring of 1980, relying almost exclusively on contemporaneous sources, including the recently released transcripts of Federal Open Market Committee (FOMC) meetings during 1979. We then present and discuss in detail the reasons for the FOMC's adoption of the reform and the communications challenge presented to the Committee during this period. Further, we examine whether the essential characteristics of the reform were consistent with monetarism; new, neo, or old-fashioned Keynesianism; nominal income targeting; and inflation targeting. The record suggests that the reform was adopted when the FOMC became convinced that its earlier gradualist strategy using finely tuned interest rate moves had proved inadequate for fighting inflation and reversing inflation expectations. The new plan had to break dramatically with established practice, allow for the possibility of substantial increases in short-term interest rates yet be politically acceptable, and convince financial market participants that it would be effective. The new operating procedures were also adopted for the pragmatic reason that they would likely succeed.Monetary policy ; Federal Open Market Committee ; Federal Reserve System - History
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