2,046 research outputs found

    Service life evaluation of rigid explosive transfer lines

    Get PDF
    This paper describes a joint Army/NASA-sponsored research program on the service life evaluation of rigid explosive transfer lines. These transfer lines are used to initiate emergency crew escape functions on a wide variety of military and NASA aircraft. The purpose of this program was to determine quantitatively the effects of service, age, and degradation on rigid explosive transfer lines to allow responsible, conservative, service life determination. More than 800 transfer lines were removed from the U.S. Army AH-1G and AH-1S, the U.S. Air Force B-1 and F-111, and the U.S. Navy F-14 aircraft for testing. The results indicated that the lines were not adversely affected by age, service, or a repeat of the thermal qualification tests on full-service lines. Extension of the service life of rigid explosive transfer lines should be considered, since considerable cost savings could be realized with no measurable decrease in system reliability

    Grid computing in image analysis

    Get PDF
    Diagnostic surgical pathology or tissue–based diagnosis still remains the most reliable and specific diagnostic medical procedure. The development of whole slide scanners permits the creation of virtual slides and to work on so-called virtual microscopes. In addition to interactive work on virtual slides approaches have been reported that introduce automated virtual microscopy, which is composed of several tools focusing on quite different tasks. These include evaluation of image quality and image standardization, analysis of potential useful thresholds for object detection and identification (segmentation), dynamic segmentation procedures, adjustable magnification to optimize feature extraction, and texture analysis including image transformation and evaluation of elementary primitives

    Interactive and automated application of virtual microscopy

    Get PDF
    Virtual microscopy can be applied in an interactive and an automated manner. Interactive application is performed in close association to conventional microscopy. It includes image standardization suitable to the performance of an individual pathologist such as image colorization, white color balance, or individual adjusted brightness. The steering commands have to include selection of wanted magnification, easy navigation, notification, and simple measurements (distances, areas). The display of the histological image should be adjusted to the physical limits of the human eye, which are determined by a view angle of approximately 35 seconds. A more sophisticated performance should include acoustic commands that replace the corresponding visual commands. Automated virtual microscopy includes so-called microscopy assistants which can be defined similar to the developed assistants in computer based editing systems (Microsoft Word, etc.). These include an automated image standardization and correction algorithms that excludes images of poor quality (for example uni-colored or out-of-focus images), an automated selection of the most appropriate field of view, an automated selection of the best magnification, and finally proposals of the most probable diagnosis. A quality control of the final diagnosis, and feedback to the laboratory determine the proposed system. The already developed tools of such a system are described in detail, as well as the results of first trials. In order to enhance the speed of such a system, and to allow further user-independent development a distributed implementation probably based upon Grid technology seems to be appropriate. The advantages of such a system as well as the present pathology environment and its expectations will be discussed in detail

    Hints of theta_13>0 from global neutrino data analysis

    Get PDF
    Nailing down the unknown neutrino mixing angle theta_13 is one of the most important goals in current lepton physics. In this context, we perform a global analysis of neutrino oscillation data, focusing on theta_13, and including recent results [Neutrino 2008, Proceedings of the XXIII International Conference on Neutrino Physics and Astrophysics, Christchurch, New Zealand, 2008 (unpublished)]. We discuss two converging hints of theta_13>0, each at the level of ~1sigma: an older one coming from atmospheric neutrino data, and a newer one coming from the combination of solar and long-baseline reactor neutrino data. Their combination provides the global estimate sin^2(theta_13) = 0.016 +- 0.010 (1sigma), implying a preference for \theta_13>0 with non-negligible statistical significance (~90% C.L.). We discuss possible refinements of the experimental data analyses, which might sharpen such intriguing indication.Comment: Minor changes in the text. Matches published version in PR

    Quasar Microlensing at High Magnification and the Role of Dark Matter: Enhanced Fluctuations and Suppressed Saddlepoints

    Full text link
    Contrary to naive expectation, diluting the stellar component of the lensing galaxy in a highly magnified system with smoothly distributed ``dark'' matter increases rather than decreases the microlensing fluctuations caused by the remaining stars. For a bright pair of images straddling a critical curve, the saddlepoint (of the arrival time surface) is much more strongly affected than the associated minimum. With a mass ratio of smooth matter to microlensing matter of 4:1, a saddlepoint with a macro-magnification of mu = 9.5 will spend half of its time more than a magnitude fainter than predicted. The anomalous flux ratio observed for the close pair of images in MG0414+0534 is a factor of five more likely than computed by Witt, Mao and Schechter if the smooth matter fraction is as high as 93%. The magnification probability histograms for macro-images exhibit distinctly different structure that varies with the smooth matter content, providing a handle on the smooth matter fraction. Enhanced fluctuations can manifest themselves either in the temporal variations of a lightcurve or as flux ratio anomalies in a single epoch snapshot of a multiply imaged system. While the millilensing simulations of Metcalf and Madau also give larger anomalies for saddlepoints than for minima, the effect appears to be less dramatic for extended subhalos than for point masses. Morever, microlensing is distinguishable from millilensing because it will produce noticeable changes in the magnification on a time scale of a decade or less.Comment: As accepted for publication in ApJ. 17 pages. Substantial revisions include a discussion of constant M/L models and the calculation of a "photometric" dark matter fraction for MG0414+053

    Virtual slides in peer reviewed, open access medical publication

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Application of virtual slides (VS), the digitalization of complete glass slides, is in its infancy to be implemented in routine diagnostic surgical pathology and to issues that are related to tissue-based diagnosis, such as education and scientific publication.</p> <p>Approach</p> <p>Electronic publication in Pathology offers new features of scientific communication in pathology that cannot be obtained by conventional paper based journals. Most of these features are based upon completely open or partly directed interaction between the reader and the system that distributes the article. One of these interactions can be applied to microscopic images allowing the reader to navigate and magnify the presented images. VS and interactive Virtual Microscopy (VM) are a tool to increase the scientific value of microscopic images.</p> <p>Technology and Performance</p> <p>The open access journal Diagnostic Pathology <url>http://www.diagnosticpathology.org</url> has existed for about five years. It is a peer reviewed journal that publishes all types of scientific contributions, including original scientific work, case reports and review articles. In addition to digitized still images the authors of appropriate articles are requested to submit the underlying glass slides to an institution (DiagnomX.eu, and Leica.com) for digitalization and documentation. The images are stored in a separate image data bank which is adequately linked to the article. The normal review process is not involved. Both processes (peer review and VS acquisition) are performed contemporaneously in order to minimize a potential publication delay. VS are not provided with a DOI index (digital object identifier). The first articles that include VS were published in March 2011.</p> <p>Results and Perspectives</p> <p>Several logistic constraints had to be overcome until the first articles including VS could be published. Step by step an automated acquisition and distribution system had to be implemented to the corresponding article. The acceptance of VS by the reader is high as well as by the authors. Of specific value are the increased confidence to and reputation of authors as well as the presented information to the reader. Additional associated functions such as access to author-owned related image collections, reader-controlled automated image measurements and image transformations are in preparation.</p> <p>Virtual Slides</p> <p>The virtual slide(s) for this article can be found here: <url>http://www.diagnosticpathology.diagnomx.eu/vs/1232133347629819</url>.</p

    Neutralino Pair Production and 3-Body Decays at e+e−e^+e^- Linear Colliders as Probes of CP Violation in the Neutralino System

    Full text link
    In the CP-invariant supersymmetric theories, the steep S-wave (slow P-wave) rise of the cross section for any non-diagonal neutralino pair production in e+e−e^+ e^- annihilation, e+e−→χ~i0χ~j0e^+e^- \to \tilde{\chi}^0_i \tilde{\chi}^0_j (i≠ji \neq j), near threshold is accompanied by the slow P-wave (steep S-wave) decrease of the fermion invariant mass distribution of the 3-body neutralino decay, χ~i0→χ~j0ffˉ\tilde{\chi}^0_i \to \tilde{\chi}^0_j f\bar{f} (f=lf=l or qq), near the end point. These selection rules, unique to the neutralino system due to its Majorana nature, guarantee that the observation of simultaneous sharp S-wave excitations of the production cross section near threshold and the lepton and quark invariant mass distribution near the end point is a qualitative, unambiguous evidence for CP violation in the neutralino system.Comment: 11 pages, 1 eps figure, a reference adde

    Neutrino wave function and oscillation suppression

    Full text link
    We consider a thought experiment, in which a neutrino is produced by an electron on a nucleus in a crystal. The wave function of the oscillating neutrino is calculated assuming that the electron is described by a wave packet. If the electron is relativistic and the spatial size of its wave packet is much larger than the size of the crystal cell, then the wave packet of the produced neutrino has essentially the same size as the wave packet of the electron. We investigate the suppression of neutrino oscillations at large distances caused by two mechanisms: 1) spatial separation of wave packets corresponding to different neutrino masses; 2) neutrino energy dispersion for given neutrino mass eigenstates. We resolve contributions of these two mechanisms.Comment: 7 page

    The Physical Range of Majorana Neutrino Mixing Parameters

    Full text link
    If neutrinos are Majorana fermions, the lepton mixing parameter space consists of six mixing parameters: three mixing angles and three CP-odd phases. A related issue concerns the physical range of the mixing parameters. What values should these take so that all physically distinguishable mixing scenarios are realized? We present a detailed discussion of the lepton mixing parameter space in the case of two and three active neutrinos, and in the case of three active and N sterile neutrinos. We emphasize that this question, which has been a source of confusion even among "neutrino" physicists, is connected to an unambiguous definition of the neutrino mass eigenstates. We find that all Majorana phases can always be constrained to lie between 0 and pi, and that all mixing angles can be chosen positive and at most less than or equal to pi/2 provided the Dirac phases are allowed to vary between -pi and pi. We illustrate our results with several examples. Finally, we point out that, in the case of new flavor-changing neutrino interactions, the lepton mixing parameter space may need to be enlarged. We properly qualify this statement, and offer concrete examples.Comment: 16 pages, 2 .eps figures, references added, minor typos correcte
    • 

    corecore