4,950 research outputs found
Asymmetric Gaussian steering: when Alice and Bob disagree
Asymmetric steering is an effect whereby an inseparable bipartite system can
be found to be described by either quantum mechanics or local hidden variable
theories depending on which one of Alice or Bob makes the required
measurements. We show that, even with an inseparable bipartite system,
situations can arise where Gaussian measurements on one half are not sufficient
to answer the fundamental question of which theory gives an adequate
description and the whole system must be considered. This phenomenon is
possible because of an asymmetry in the definition of the original
Einstein-Podolsky-Rosen paradox and in this article we show theoretically that
it may be demonstrated, at least in the case where Alice and Bob can only make
Gaussian measurements, using the intracavity nonlinear coupler.Comment: 5 Pages, 4 Figure
Aerodynamic design for improved manueverability by use of three-dimensional transonic theory
Improvements in transonic maneuver performance by the use of three-dimensional transonic theory and a transonic design procedure were examined. The FLO-27 code of Jameson and Caughey was used to design a new wing for a fighter configuration with lower drag at transonic maneuver conditions. The wing airfoil sections were altered to reduce the upper-surface shock strength by means of a design procedure which is based on the iterative application of the FLO-27 code. The plan form of the fighter configuration was fixed and had a leading edge sweep of 45 deg and an aspect ratio of 3.28. Wind-tunnel tests were conducted on this configuration at Mach numbers from 0.60 to 0.95 and angles of attack from -2 deg to 17 deg. The transonic maneuver performance of this configuration was evaluated by comparison with a wing designed by empirical methods and a wing designed primarily by two-dimensional transonic theory. The configuration designed by the use of FLO-27 had the same or lower drag than the empirical wing and, for some conditions, lower drag than the two-dimensional design. From some maneuver conditions, the drag of the two-dimensional design was somewhat lower
The construction and evaluation of four series of lessons to stimulate the flow of ideas in the creative writing of fourth, fifth, and sixth grade pupils.
Thesis (Ed.M.)--Boston Universit
A biophysical model of prokaryotic diversity in geothermal hot springs
Recent field investigations of photosynthetic bacteria living in geothermal
hot spring environments have revealed surprisingly complex ecosystems, with an
unexpected level of genetic diversity. One case of particular interest involves
the distribution along hot spring thermal gradients of genetically distinct
bacterial strains that differ in their preferred temperatures for reproduction
and photosynthesis. In such systems, a single variable, temperature, defines
the relevant environmental variation. In spite of this, each region along the
thermal gradient exhibits multiple strains of photosynthetic bacteria adapted
to several distinct thermal optima, rather than the expected single thermal
strain adapted to the local environmental temperature. Here we analyze
microbiology data from several ecological studies to show that the thermal
distribution field data exhibit several universal features independent of
location and specific bacterial strain. These include the distribution of
optimal temperatures of different thermal strains and the functional dependence
of the net population density on temperature. Further, we present a simple
population dynamics model of these systems that is highly constrained by
biophysical data and by physical features of the environment. This model can
explain in detail the observed diversity of different strains of the
photosynthetic bacteria. It also reproduces the observed thermal population
distributions, as well as certain features of population dynamics observed in
laboratory studies of the same organisms
Unusual Radiographic Presentation of Pneumocystis Pneumonia in a Patient with AIDS.
Pneumocystis jirovecii pneumonia (PCP) typically presents as an interstitial and alveolar process with ground glass opacities on chest computed tomography (CT). The absence of ground glass opacities on chest CT is thought to have a high negative predictive value for PCP in individuals with AIDS. Here, we report a case of PCP in a man with AIDS who presented to our hospital with subacute shortness of breath and a nonproductive cough. While his chest CT revealed diffuse nodular rather than ground glass opacities, bronchoscopy with bronchoalveolar lavage and transbronchial biopsies confirmed the diagnosis of PCP and did not identify additional pathogens. PCP was not the expected diagnosis based on chest CT, but it otherwise fit well with the patient's clinical and laboratory presentation. In the era of combination antiretroviral therapy, routine prophylaxis for PCP, and increased use of computed tomography, it may be that PCP will increasingly present with nonclassical chest radiographic patterns. Clinicians should be aware of this presentation when selecting diagnostic and management strategies
Recommended from our members
Aqueous Processes for Dissolution of Uranium-Molybdenum Alloy Reactor Fuel Elements
Methods for dissolving unirradiated uranium-molybdenum alloy reactcr fuels in nitric acid, nitric acid--ferric nitrate, and nitric acid-- phosphoric acid solutions were studied on a laboratory scale. Flowsheets based on the results propose dissolution of alloys containing 3% molybdenum in boiling 6 M HNO/ sub 3/ to yield stsble solutions that are 0.6 M in uranium and 3 to 4 M in nitric acid. The uranium can then be easily decontaminated and recovered in a conventional Purex-type tributyl phosphate solvent extraction process. Alloys containing 10% molybdenum would be dissolved in boiling 11 M HNO/sub 3/, allowing molybdic oxide to precipitate. The molybdic oxide, which carries 5-10% of the uranium, is removed by centrifugation and the acidity of the supernatant solution adjusted tc allow recovery of the uranium by Purex-type solvent extraction procedures. The uranium carried by the molybdic oxide is recovered after the MoO/ sub 3/ is dissolved in warm 5 M NaOH. Less than 0.1% of the uranium is solubilized during the caustic dissolution. Alternative methods investigated involve dissolution in nitric acid containing 0.5 to 1 M ferric nitrate to complex the molybdenum. These techniques lead to undesirably large volumes of high-level solvent extraction waste solutions. Phosphate ion is also effective in complexing molybdenum; however, its use in the dissolvent would be purposeless since it must be complexed with iron during solvent extraction. Rates of reaction of the various alloys and the solubility of molybdic oxide were determined in nitric acid, nitric acid-- ferric nitrate, and nitric acid-- phosphonic acid solutions. (auth
First Annual Logistics Faculty Salary Survey
While the Association to Advance Collegiate Schools of Business International (AACSB) conducts an annual survey of business school faculty and administrative salaries, the data do not include salary figures for logistics (and related areas such as transportation and supply chain management) faculty. Since the growth in number of logistics faculty positions has continued to exceed the output of doctoral programs in the field for more than a decade, it is logical to assume that logistics faculty salaries, at all levels, are increasing. However, without factual data, what salary should a new logistics Ph.D. expect, and what should an administrator budget for a logistics faculty position? In order to provide such factual data, the authors developed an electronic salary survey and distributed it to 236 faculty at colleges and universities in the United States. It is the intent of the authors to conduct the salary survey annually, and report the results in the Journal of Transportation Management
Multi-frequency fine resolution imaging radar instrumentation and data acquisition
Development of a dual polarized L-band radar imaging system to be used in conjunction with the present dual polarized X-band radar is described. The technique used called for heterodyning the transmitted frequency from X-band to L-band and again heterodyning the received L-band signals back to X-band for amplification, detection, and recording
- …