4,775 research outputs found
Entanglement and symmetry in permutation symmetric states
We investigate the relationship between multipartite entanglement and
symmetry, focusing on permutation symmetric states. We use the Majorana
representation, where these states correspond to points on a sphere. Symmetry
of the representation under rotation is equivalent to symmetry of the states
under products of local unitaries. The geometric measure of entanglement is
thus phrased entirely as a geometric optimisation, and a condition for the
equivalence of entanglement measures written in terms of point symmetries.
Finally we see that different symmetries of the states correspond to different
types of entanglement with respect to SLOCC interconvertibility.Comment: 4 pages, 2 figures. Preliminary versions of some of these results
were presented in the QIT 16 workshop in Japan, D. Markham, Proceedings of
QIT 16, Japan (2007). Updated to reflect changes for publication: expanded
proofs and some new examples give
Spectral characterization of the LANDSAT Thematic Mapper sensors
The spectral coverage characteristics of the two thematic mapper instruments were determined by analyses of spectral measurements of the optics, filters, and detectors. The following results are presented: (1) band 2 and 3 flatness was slightly below specification, and band 7 flatness was below specification; (2) band 5 upper-band edge was higher than specifications; (3) band 2 band edges were shifted upward about 9 nm relative to nominal; and (4) band 4, 5, and 7 lower band edges were 16 to 18 nm higher then nominal
Spectral characterization of the LANDSAT-D multispectral scanner subsystems
Relative spectral response data for the multispectral scanner subsystems (MSS) to be flown on LANDSAT-D and LANDSAT-D backup, the protoflight and flight models, respectively, are presented and compared to similar data for the Landsat 1,2, and 3 subsystems. Channel-bychannel (six channels per band) outputs for soil and soybean targets were simulated and compared within each band and between scanners. The two LANDSAT-D scanners proved to be nearly identical in mean spectral response, but they exhibited some differences from the previous MSS's. Principal differences between the spectral responses of the D-scanners and previous scanners were: (1) a mean upper-band edge in the green band of 606 nm compared to previous means of 593 to 598 nm; (2) an average upper-band edge of 697 nm in the red band compared to previous averages of 701 to 710 nm; and (3) an average bandpass for the first near-IR band of 702-814 nm compared to a range of 693-793 to 697-802 nm for previous scanners. These differences caused the simulated D-scanner outputs to be 3 to 10 percent lower in the red band and 3 to 11 percent higher in the first near-IR band than previous scanners for the soybeans target. Otherwise, outputs from soil and soybean targets were only slightly affected. The D-scanners were generally more uniform from channel to channel within bands than previous scanners
Introduction to Thematic Mapper investigations. Section 1: Radiometry. Section 2: Geometry
An overview of papers which deal with radiometric characterization of the TM sensor is presented. Spectral characteristics are summarized. The geometric accuracy of TM are also examined. Aspects of prelaunch and post launch sensor performance, ground processing techniques, and error correction are also investigated
Studies on a Murine Model of Trichomoniasis
A mouse model of trichomoniasis was developed using T. vaqinalis,intravaqinally inoculated into Balb/c mice. Although the infection rates obtained were not consistently, or frequently, 100%, over 2/3 of experiments yielded rates of over 50%. Estrogen-treatment of mice, prior to intravaginal inoculation with the parasites, was found to be necessary for the establishment of infection but other variables such as route, timing and amount of estrogen, diet fed to mice, age and breed of mice and variables in maintenance of the parasite line proved to be of less importance. The administration of ferric ammonium citrate, prior to infection, was found to significantly increase the infection rates. The role of the pH of the vagina and the iron and zinc content of the vaginal secretions was also investigated. The pH of the murine vagina was found to be around neutral and this was not affected by estrogen-treatment or the presence of infection. Treatment of the mouse with iron, however, does significantly increase the vaginal pH. The iron and zinc content of the vagina was extremely low. The importance of the murine immune response was also investigated by the use of SolcoTrichovac, a vaccine in use for the treatment of trichomoniasis, and 'vaccines' prepared from parasite homogenates. Neither of these preparations appeared to have any therapeutic effect. Overall, although this mouse model is not ideal for studying trichomoniasis,it proved to be useful in study of the vaginal microenvironment, and its relationship with the presence of T. vaginalis, and an investigation of the immune response to infection
Development of an orthotropic hole element
A finite element was developed which adequately represents the state of stress in the region around a circular hole in orthotropic material experiencing reasonably general loading. This was achieved with a complementary virtual work formulation of the stiffness and stress matrices for a square element with center circular hole. The assumed stress state provides zero shearing stress on the hole boundary, so the element is suitable for problems involving load transfer without friction. The element has been implemented in the NASTRAN computer program, and sample problem results are presented
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