58 research outputs found

    Towards attosecond measurement of dynamics in multi-electron systems

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    Recent developments in laser science have made it possible to experimentally study ultrafast electron dynamics in atoms and molecules directly by using ultrashort pulses on the order of tens of attoseconds. It is paramount, both for current understanding and planning of future experiments and applications, that we decipher how short pulses interact with the medium. We model attosecond dynamics of multi-electron systems following three themes: (1) propagation and distortion of pulses in absorbing noble gases, (2) simulation of atoms and molecules under the effects of pump and probe pulses, (3) coherence and polarization effects on transient absorption. First, using the Kramers-Kronig relations and a fast and stable numerical algorithm based on Mobius transformations, we model the distortion of XUV pulses propagating in noble gases. Our simulations show rich features including pulse stretching, partial narrowing, partial apparent super-luminality, and tail development. Second, we deploy the density matrix formalism using Lindblad terms and the three Hilbert spaces method, incorporating multi-channel and Auger ionization compactly and consistently, to model coherence observed in pump-probe attosecond transient absorption studies of Kr II. We explain how coherent noble cation states are produced. Density matrix elements for the excited Kr II 3d_3/2 and 3d_5/2 levels caused by a resonant z-polarized 80 eV 150 as probe pulse are simulated and the resulting population densities and induced dipole moments are analyzed, including nonlinear contributions. In order to model pulse propagation, we develop absorption theory for arbitrary polarization angle and point out how coherence effects distort the Beer-Lambert law and discuss experimental implications. Third, we investigate non-adiabatic effects in attosecond dynamics in molecules driven by a laser field. We use the Algebraic Diagrammatic Construction method and Arnoldi-Lanczos TDSE programs to simulate N2 and oligocenes for 400 nm, 800 nm and 1.6 micron wavelengths with various laser intensities and polarizations. We determine the onset of non-adiabaticity in N2, benzene and naphthalene. Last, but not least, I describe my experimental contribution to the new Imperial College beamline.Open Acces

    The design of whispering gallery mirrors for soft x-ray lasers

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    Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.Includes bibliographical references.by Tsen-Yu Hung.B.S

    Taiwanese Dermatological Association consensus for the management of atopic dermatitis

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    AbstractBackground/ObjectiveThis report describes the 2014 consensus of the Taiwanese Dermatological Association (TDA) regarding the treatment of atopic dermatitis (AD). The TDA consensus is distributed to practices throughout Taiwan to provide recommendations for therapeutic approaches for AD patients to improve their quality of life.MethodsThe information in the consensus was agreed upon by a panel of national experts at TDA AD consensus meetings held on March 16, May 4, and June 29, 2014. The consensus was in part based on the 2013 Asia–Pacific AD guidelines and the guidelines of the American Academy of Dermatology, with modification to reflect the clinical practice in Taiwan.ResultsThe amendments were drafted after scientific discussions focused on the quality of evidence, risk, and benefits; all the consensus contents were voted on by the participating dermatologists, with approval by at least 75% for inclusion.ConclusionThe consensus provides a comprehensive overview of treatment for AD, with some local and cultural considerations for practitioners in Taiwan, especially the use of wet dressings/wraps, systemic immunomodulatory agents, and complementary therapies

    Optics and Quantum Electronics

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    Contains table of contents for Section 2 and reports on eighteen research projects.National Science Foundation (Grant EET 87-00474)Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAALO3-89-C-0001)Charles Stark Draper Laboratory (Grant DL-H-285408)Charles Stark Draper Laboratory (Grant DL-H-2854018)National Science Foundation (Grant EET 87-03404)National Science Foundation (Grant ECS 84-06290)U.S. Air Force - Office of Scientific Research (Contract F49620-88-C-0089)AT&T Bell FoundationNational Science Foundation (Grant ECS 85-52701)National Institutes of Health (Grant 5-RO1-GM35459)Massachusetts General Hospital (Office of Naval Research Contract N00014-86-K-0117)Lawrence Livermore National Laboratory (Subcontract B048704

    Optics and Quantum Electronics

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    Contains reports on eleven research projects.National Science Foundation (Grant EET 87-00474)Joint Services Electronics Program (Contract DAALO03-86-K-O002)Charles Stark Draper Laboratory, Inc. (Grant DL-H-2854018)National Science Foundation (Grant DMR 84-18718)National Science Foundation (Grant EET 87-03404)National Science Foundation (ECS 85-52701)US Air Force - Office of Scientific Research (Contract AFOSR-85-0213)National Institutes of Health (Contract 5-RO1-GM35459)US Navy - Office of Naval Research (Contract N00014-86-K-0117

    Fosmid library end sequencing reveals a rarely known genome structure of marine shrimp Penaeus monodon

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    <p>Abstract</p> <p>Background</p> <p>The black tiger shrimp (<it>Penaeus monodon</it>) is one of the most important aquaculture species in the world, representing the crustacean lineage which possesses the greatest species diversity among marine invertebrates. Yet, we barely know anything about their genomic structure. To understand the organization and evolution of the <it>P. monodon </it>genome, a fosmid library consisting of 288,000 colonies and was constructed, equivalent to 5.3-fold coverage of the 2.17 Gb genome. Approximately 11.1 Mb of fosmid end sequences (FESs) from 20,926 non-redundant reads representing 0.45% of the <it>P. monodon </it>genome were obtained for repetitive and protein-coding sequence analyses.</p> <p>Results</p> <p>We found that microsatellite sequences were highly abundant in the <it>P. monodon </it>genome, comprising 8.3% of the total length. The density and the average length of microsatellites were evidently higher in comparison to those of other taxa. AT-rich microsatellite motifs, especially poly (AT) and poly (AAT), were the most abundant. High abundance of microsatellite sequences were also found in the transcribed regions. Furthermore, <it>via </it>self-BlastN analysis we identified 103 novel repetitive element families which were categorized into four groups, <it>i.e</it>., 33 WSSV-like repeats, 14 retrotransposons, 5 gene-like repeats, and 51 unannotated repeats. Overall, various types of repeats comprise 51.18% of the <it>P. monodon </it>genome in length. Approximately 7.4% of the FESs contained protein-coding sequences, and the Inhibitor of Apoptosis Protein (IAP) gene and the Innexin 3 gene homologues appear to be present in high abundance in the <it>P. monodon </it>genome.</p> <p>Conclusions</p> <p>The redundancy of various repeat types in the <it>P. monodon </it>genome illustrates its highly repetitive nature. In particular, long and dense microsatellite sequences as well as abundant WSSV-like sequences highlight the uniqueness of genome organization of penaeid shrimp from those of other taxa. These results provide substantial improvement to our current knowledge not only for shrimp but also for marine crustaceans of large genome size.</p

    Optics and Quantum Electronics

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    Contains table of contents for Section 3 and reports on twenty-one research projects.Joint Services Electronics Program Contract DAAL03-89-C-0001Joint Services Electronics Program Contract DAAL03-92-C-0001U.S. Air Force - Office of Scientific Research Contract F49620-91-C-0091Charles S. Draper Laboratories Contract DL-H-441629MIT Lincoln LaboratoryCharles S. Draper Laboratories, Inc. Contract DL-H-418478Fujitsu LaboratoriesNational Science Foundation Grant ECS 90-12787National Center for Integrated PhotonicsNational Science Foundation Grant EET 88-15834National Science Foundation Grant ECS 85-52701U.S. Air Force - Office of Scientific Research Contract F49620-88-C-0089U.S. Navy - Office of Naval Research Contract N00014-91-C-0084U.S. Navy - Office of Naval Research Grant N00014-91-J-1956Johnson and Johnson Research GrantNational Institutes of Health Contract 2-R01-GM35459U.S. Department of Energy Grant DE-FG02-89 ER14012-A00
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