7,797 research outputs found

    A Quadratic Deformation of the Heisenberg-Weyl and Quantum Oscillator Enveloping Algebras

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    A new 2-parameter quadratic deformation of the quantum oscillator algebra and its 1-parameter deformed Heisenberg subalgebra are considered. An infinite dimensional Fock module representation is presented which at roots of unity contains null vectors and so is reducible to a finite dimensional representation. The cyclic, nilpotent and unitary representations are discussed. Witten's deformation of sl2sl_2 and some deformed infinite dimensional algebras are constructed from the 1d1d Heisenberg algebra generators. The deformation of the centreless Virasoro algebra at roots of unity is mentioned. Finally the SLq(2)SL_q(2) symmetry of the deformed Heisenberg algebra is explicitly constructed.Comment: 23 pages of plain TeX (with phyzzx.tex macros). I've made a few minor corrections and added 2 reference

    Frost Hardiness of Iraqi Wheat genotypes

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    Frost hardiness level in winter cereals is especially temperature dependent. The low temperature which kills 50% of plants (LT50) is considered to be a standard indicator of frost hardiness level of plant. Frost hardiness is considered the most important parameter for the field survival which is the ultimate measure of winter-hardiness of a cultivar. This study aimed to determine the genetic level of frost hardiness of five Middle Eastern varieties (Abu-Ghraib, Fatah, IPA 95, IPA 99, and Sham 6) in comparison to the European cultivar (Claire). All of the Middle Eastern varieties tested showed very similar LT50’s in the nonacclimated state, whilst when of acclimated they responded in different ways to freezing temperatures. Abu-Ghraib and Claire showed more tolerance than the other cultivars

    Virtual urban traffic network simulator

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 41).In this project, I designed and implemented a virtual urban traffic network simulator. The simulator serves as a testbed for human-subject experiments to determine driver behavior in road networks and also as a platform for testing route-planning algorithms. The simulator was implemented using the C4 game engine and OpenGL. The simulator is capable of producing both 3- and 2-dimensional visualizations of a traffic network. In this thesis, I describe the key components of the simulator, the necessary inputs, and the expected outputs. I verify operation of the simulator through observation of the actual system outputs.by Jason Uh.M.Eng

    Virtual edge illumination and one dimensional beam tracking for absorption, refraction, and scattering retrieval

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    We propose two different approaches to retrieve x-ray absorption, refraction, and scattering signals using a one dimensional scan and a high resolution detector. The first method can be easily implemented in existing procedures developed for edge illumination to retrieve absorption and refraction signals, giving comparable image quality while reducing exposure time and delivered dose. The second method tracks the variations of the beam intensity profile on the detector through a multi-Gaussian interpolation, allowing the additional retrieval of the scattering signal

    llokutionshierarchie im argumentativen Dialog

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    In dem Beitrag wird der Begriff der Illokutionshierarchie vorgestellt und gegenüber der Originalkonzeption modifiziert. Seine Tragfähigkeit und Fruchtbarkeit wird untersucht, indem er für die Analyse argumentativer Texte nutzbar gemacht wird. Argumentationen werden als hierarchisch strukturierte Komplexe von Illokutionen betrachtet. Diese Konzeption wird anhand eines authentischen argumentativen Gespräches exemplarisch angewendet

    Instruction Re-Selection for Iterative Modulo Scheduling on High Performance Multi-Issue DSPs

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    An iterative modulo scheduling is very important for compilers targeting high performance multi-issue digital signal processors. This is because these processors are often severely limited by idle state functional units and thus the reduced idle units can have a positively significant impact on their performance. However, complex instructions, which are used in most recent DSPs such as mac, usually increase data dependence complexity, and such complex dependencies that exist in signal processing applications often restrict modulo scheduling freedom and therefore, become a limiting factor of the iterative modulo scheduler. In this work, we propose a technique that efficiently reselects instructions of an application loop code considering dependence complexity, which directly resolve the dependence constraint. That is specifically featured for accelerating software pipelining performance by minimizing length of intrinsic cyclic dependencies. To take advantage of this feature, few existing compilers support a loop unrolling based dependence relaxing technique, but only use them for some limited cases. This is mainly because the loop unrolling typically occurs an overhead of huge code size increment, and the iterative modulo scheduling with relaxed dependence techniques for general cases is an NP-hard problem that necessitates complex assignments of registers and functional units. Our technique uses a heuristic to efficiently handle this problem in pre-stage of iterative modulo scheduling without loop unrolling

    Degenerate Stars and Gravitational Collapse in AdS/CFT

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    We construct composite CFT operators from a large number of fermionic primary fields corresponding to states that are holographically dual to a zero temperature Fermi gas in AdS space. We identify a large N regime in which the fermions behave as free particles. In the hydrodynamic limit the Fermi gas forms a degenerate star with a radius determined by the Fermi level, and a mass and angular momentum that exactly matches the boundary calculations. Next we consider an interacting regime, and calculate the effect of the gravitational back-reaction on the radius and the mass of the star using the Tolman-Oppenheimer-Volkoff equations. Ignoring other interactions, we determine the "Chandrasekhar limit" beyond which the degenerate star (presumably) undergoes gravitational collapse towards a black hole. This is interpreted on the boundary as a high density phase transition from a cold baryonic phase to a hot deconfined phase.Comment: 75 page

    Immunological Changes after Cancer Treatment and Participation in an Exercise Program

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    Purpose: The purpose of this investigation was to evaluate the impact of undertaking peripheral blood stem cell transplantation (PBST) on T-cell number and function, and to determine the role of a mixed type, moderate intensity exercise program in facilitating the recovery of T-cell number and function. Methods: Immunological measures of white blood cell, lymphocyte, CD3+, CD4+, and CD8+ counts, and CD3+ cell function were assessed pretransplant (PI), immediately posttransplant (PII), and 1 month (I1), 2 months (I2) and 3 months (PIII) posttransplant. After PII, 12 patients were divided equally into a control group (CG) or exercise intervention group (EG). Results: Lower total T-cell, helper T-cell, and suppressor T-cell counts (P < 0.01), as well as lower T-cell function (P < 0.01), when compared with normative data, were found at PI. More specifically, 88% of the group had CD3+, CD4+, and CD8+ counts that were more than 40%, 20%, and 50% below normal at PI, respectively. Undertaking a PBST caused further adverse changes to the total leukocyte, lymphocyte, CD3+, CD4+ and CD8+ count, and the helper/suppressor ratio. Although CD8+ counts had returned to normal by PIII, CD3+, CD4+, and the CD4+/CD8+ ratio remained significantly lower than normative data (P < 0.01), with 66%, 100%, and 100% of the subject group reporting counts and ratios, respectively, below the normal range. Conclusion: The PBST patients were immunocompromised before undertaking the transplant, and the transplant procedure imposed further adverse changes to the leukocyte and lymphocyte counts. The leukocyte and CD8+ counts returned to normal within 3 months posttransplant; however, the other immunological parameters assessed demonstrated a delayed recovery. Although participation in the exercise program did not facilitate a faster immune cell recovery, neither did the exercise program hinder or delay recovery
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