185 research outputs found

    UCLA Intermediate Energy Nuclear and Particle Physics Research: Final Report

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    This project covers the following research: (a) Investigations into the structure of the proton and neutron. This is done by investigating the different resonance states of nucleons with beams of tagged, polarized photons, linearly as well as circularly, incident on polarized hydrogen/deuterium targets and measuring the production of {pi}{sup #25;0}, 2{pi}{sup #25;}0, 3{pi}{sup #25;0}, {eta}#17;, {eta}', {omega}, etc. The principal detector is the Crystal Ball multiphoton spectrometer which has an acceptance of nearly 4#25;. It has been moved to the MAMI accelerator facility of the University of Mainz, Germany. We investigate the conversion of electromagnetic energy into mesonic matter and conversely. (b) We investigate the consequences of applying the "standard" symmetries of isospin, GâÂÂparity, charge conjugation, C, P, T, and chirality using rare and forbidden decays of light mesons such as the {eta}#17;,{eta}' and {omega}. We also investigate the consequences of these symmetries being slightly broken symmetries. We do this by studying selected meson decays using the Crystal Ball detector. (c) We determine the mass, or more precisely the mass difference of the three light quarks (which are inputs to Quantum Chromodynamics) by measuring the decay rate of specially selected {eta}#17; and {eta}' decay modes, again we use the Crystal Ball. (d)We have started a new program to search for the 33 missing cascade baryons using the CLAS detector at the Thomas Jefferson Laboratory. Cascade resonances are very special: they have double strangeness and are quite narrow. This implies that they can be discovered by the missing mass technique in photoproduction reactions such as in {gamma}p{yields}{Xi}{sup #4;âÂÂ}K{sup +}K{sup +}. The cascade program is of particular importance for the upgrade to 12 GeV of the CLAS detector and for design of the Hall D at JLab. (e) Finally, we are getting more involved in a new program to measure the hadronic matter form factor of complex nuclei, in particular the "neutron skin" of {sup 208}Pb, which is of great interest to astroparticle physics for determining the properties of neutron stars. Processes of study are coherent and nonâÂÂcoherent #25;0 photoproduction. The Crystal Ball is uniquely suited for these studies because of the large acceptance, good direction and energy resolution and it is an inclusive detector for the #25;{pi}{sup 0} final state and exclusive for background such as 2#25;{pi}{sup 0}

    Hydrodynamics of transient processes in a well with an electric submersible pump

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    The relevance. Associated with the problem of increase in efficiency of algorithms for monitoring and controlling the dynamic operation modes of wells equipped with an electric submersible pump with adjustable supply. The result summarizes and develops the previously published solution on the design of a dynamic well model, through the transition from linearized correlations to quadratic relationships between states at key points of a lift. These points properly reflect the observed forms of behavior in transient and equilibrium operating modes at full start-stop control ranges. The main aim. Updated description of a comprehensive quadratic barometric model of the «reservoir–lift–electric pump–well head» type well, focused on the tasks of automatic control and regulation in real time. Objects. Well with frequency-regulated submersible pump. Methods. Material balance, percolation, hydrostatics, quadratic kinetics of friction losses, numerical modeling of differential equations, finite-dimensional description of the complex hydrodynamics of the well, taking into account the potential and kinetic head losses in the lift. Results: (1) Updated mathematical description of the hydrodynamics of the well with an electric submersible pump creates the basis for: • more reliable solution of inverse problems of parametric model support according to the data of field control, • refined assessment of the adjustment potential, predicting the dynamics of a possible system output beyond the boundaries of functional stability, • technologies of numerical and analytical design of optimal solutions when selecting the parameters of arrangement and laws of operational regulation, • synthesis of dynamic observers of an extended state vector synchronously operating with the dynamics of controlling well-head and deep pressure. (2) The results of the computational analysis demonstrate a complex behavior that does not match the graph of the inflow and pump supply, when changing the frequency and wellhead pressure. This explains the observed effect of the multi-tempoity of transient processes during starts and stops and possible instability of the supply with a sharp decrease in frequency. (3) Estimates of discrepancy between the solutions for a quadratic model and a linearized prototype indicate an increase in errors of linearized analysis with strong deviations of operating modes from the equilibrium-calculated states. The refinements in dynamically disturbed operating modes delivered by the updated model are important for improving the reliability of operational control systems and parametric estimation for data control mode states

    Eta photoproduction off the neutron at GRAAL

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    The gamma n -> eta n quasi-free cross section reveals a resonant structure at W ~ 1.675 GeV. This structure may be a manifestation of a baryon resonance. A priori its properties, the possibly narrow width and the strong photocoupling to the neutron, look surprising. This structure may also signal the existence of a narrow state.Comment: To appear in Proceedings of Workshop on the Physics of Excited Nucleons NSTAR2005, 12 - 15 October 2005, Tallahassee, Florida, US

    Eta photoproduction off the neutron at GRAAL: Evidence for a resonant structure at W=1.67 GeV

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    New (preliminary) data on eta photoproduction off the neutron are presented. These data reveal a resonant structure at W=1.67 GeV.Comment: 8 pages, 4 figures. Published in Proceedings of Workshop on the Physics of Excited Nucleons NSTAR2004, Grenoble, France, March 24 - 27, pg.19

    Lowering the Light Speed Isotropy Limit: European Synchrotron Radiation Facility Measurements

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    The measurement of the Compton edge of the scattered electrons in GRAAL facility in European Synchrotron Radiation Facility (ESRF) in Grenoble with respect to the Cosmic Microwave Background dipole reveals up to 10 sigma variations larger than the statistical errors. We now show that the variations are not due to the frequency variations of the accelerator. The nature of Compton edge variations remains unclear, thus outlining the imperative of dedicated studies of light speed anisotropy

    Eta photoproduction on the neutron at GRAAL: Measurement of the differential cross section

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    In this contribution, we will present our first preliminary measurement of the differential cross section for the reaction gamma+n->eta+n. Comparison of the reactions gamma+p->eta+p for free and bound proton (D2 target) will also be discussed.Comment: 6 pages, 4 figures, Proceedings of the 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon, August 29-September 4 2004, Beijing, Chin

    A new limit on the light speed isotropy from the GRAAL experiment at the ESRF

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    When the electrons stored in the ring of the European Synchrotron Radiation Facility (ESRF, Grenoble) scatter on a laser beam (Compton scattering in flight) the lower energy of the scattered electron spectra, the Compton Edge (CE), is given by the two body photon-electron relativistic kinematics and depends on the velocity of light. A precision measurement of the position of this CE as a function of the daily variations of the direction of the electron beam in an absolute reference frame provides a one-way test of Relativistic Kinematics and the isotropy of the velocity of light. The results of GRAAL-ESRF measurements improve the previously existing one-way limits, thus showing the efficiency of this method and the interest of further studies in this direction.Comment: Proceed. MG12 meeting, Paris, July, 200

    The role of a nurse in primary prevention of breast cancer

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    The article analyzes the predisposition of patients to the development of breast cancer. Determining the predisposition is very important, since it allows for timely diagnosis and prevention of the disease. It is the nurse who conducts questionnaire screenings to identify patients who are prone to cancer.В статье анализируется предрасположенность пациентов к развитию рака молочной (грудной) железы. Определение предрасположенности актуально, так как позволяет провести своевременную диагностику и профилактику заболевания. Именно медицинская сестрапроводит анкетные скрининги, для выявления пациентов, подверженных онкологической заболеваемости

    Limits on light-speed anisotropies from Compton scattering of high-energy electrons

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    The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ESRF's GRAAL facility constrains such anisotropies representing the first non-threshold collision-kinematics study of Lorentz violation. When interpreted within the minimal Standard-Model Extension, this result yields the two-sided limit of 1.6 x 10^{-14} at 95% confidence level on a combination of the parity-violating photon and electron coefficients kappa_{o+} and c. This new constraint provides an improvement over previous bounds by one order of magnitude.Comment: 4 pages, 4 figure

    Характеристика липидного профиля мембран альвеолярных макрофагов у больных бронхиальной астмой

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    The aim of the present investigation was to study the lipid metabolism in alveolar macrophages in patients with predasthma and bronchial asthma. In alveolar macrophages levels of membrane phospholipids, cholesterine, and the activity of phospholipase A2 were measured. In patients with bronchial asthma, changes in lipid phase of alveolar macrophage membranes, the increase of toxic phospholipid degradation products and cholesterine, and the rise of the phospholipase A2 activity were found. During the course of treatment, lipid metabolism in asthmatics did not return to normal values. The tendency to normalisation was obseived in patients with predasthma remission only.Целью настоящего исследования было изучение липидного метаболизма альвеолярных макрофагов у больных с предастмой и бронхиальной астмой. Были измерены уровни мембранных фосфолипидов, холестерина и активности фосфолипазы А2. У пациентов с бронхиальной астмой были обнаружены изменения в липидной фазе мембран альвеолярных макрофагов, увеличение продуктов токсической деградации фосфолипидов и холестерина и подъем активности фосфолипазы А2. В течение курса лечения липидный метаболизм у астматиков не возвращался к нормальным величинам. Тенденция к нормализации наблюдалась только у больных с ремиссией предастмы
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