65 research outputs found

    Lorentz and CPT Violation in Neutrinos

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    A general formalism is presented for violations of Lorentz and CPT symmetry in the neutrino sector. The effective hamiltonian for neutrino propagation in the presence of Lorentz and CPT violation is derived, and its properties are studied. Possible definitive signals in existing and future neutrino-oscillation experiments are discussed. Among the predictions are direction-dependent effects, including neutrino-antineutrino mixing, sidereal and annual variations, and compass asymmetries. Other consequences of Lorentz and CPT violation involve unconventional energy dependences in oscillation lengths and mixing angles. A variety of simple models both with and without neutrino masses are developed to illustrate key physical effects. The attainable sensitivities to coefficients for Lorentz violation in the Standard-Model Extension are estimated for various types of experiments. Many experiments have potential sensitivity to Planck-suppressed effects, comparable to the best tests in other sectors. The lack of existing experimental constraints, the wide range of available coefficient space, and the variety of novel effects imply that some or perhaps even all of the existing data on neutrino oscillations might be due to Lorentz and CPT violation.Comment: 25 pages REVTe

    Синусныи гистиоцитоз кожи лица нелангергансового типа (кожная форма болезни Розаи — Дорфмана)

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    An extremely rare case of sinus histiocytosis of the non-Langerhans cell histiocytoses type is described in 55-year-old patient with isolated localization of cutanious lesion on the right cheek without involvement of nodular structures. Main skin lesion was an erythematous-cyanotic node with multiple milia-like lesions on the top of it. Histologically revealed feature was a large number of plasma cells, besides phenomenon of emperipolesis was described, which was first falsely perceived by pathologists as phagocytosis. In immu-nohistochemistry assay the changes were characterized by proliferation of large polygonal histiocytes with accumulation of pentalamellar markers in its cytoplasm (protein S-100, CD68).Описан чрезвычайно редкий случай синусного гистиоцитоза нелангергансового типа у пациентки 55 лет с изолированной локализацией процесса на коже правой щеки, без вовлечения нодулярных структур. Основным кожным проявлением был узел эритематозно-синюшного цвета, с наличием множественных милиумподобных высыпаний на поверхности. При патоморфологическом исследовании особенностью являлось наличие большого количества плазматических клеток, кроме этого описан феномен эмпериполеза, который сначала был ошибочно воспринят морфологами как «фагоцитоз». При иммуногистохимическом исследовании изменения характеризовались пролиферацией крупных полигональных гистиоцитов с накоплением пенталамеллярных маркеров в их цитоплазме (протеин S-100, CD68)

    A completely self-contained cryogen-free dilution refrigerator, the TritonDR™

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    Oxford Instruments have developed a new dilution refrigerator for ultralow temperatures down to below 35 mK. The TritonDRTM system is a continuous cryogenic cycle dilution refrigerator. The refrigerator is driven by a closed cycle cryocooler and hence requires no liquid cryogens. The system has a dedicated electronic control unit and software that provides full control of operation

    Comment on "Quantum diffusion of 3-He impurities in solid 4- He"

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    In this comment I show that the experimental data on quantum diffusion of 3-He impurities in solid 4-He can be explained using the adopted quasiparticle theory. The contention by E.G. Kisvarsanyi and N.S. Sullivan (KS) in Phys.Rev.B v. 48, 16557 (1993) as well as in their Reply (ibid. v. 55, 3989 (1997)) to the Grigor'ev's Comment (Phys.Rev. B v. 55, 3987 (1997)) that "Pushkarov's theory of phonon scattering fails to fit the data by very large factors" is groundless and may result from their bad arithmetical error. This means that the phonon-impurity scattering mechanism of diffusion is consistent with experiment and its neglecting by KS makes their results questionable.Comment: RevTex, 5 pages, no figures, to be published in Phys.Rev.

    Аппликационная брахитерапия в лечении пациента с рецидивом саркомы Капоши спорадического типа

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    The authors describe a patient of 63 years with a classic Kaposi’s sarcoma relapse, having contraindi - cations for cytostatic therapy. They also present literature data concerning the etiology, pathogenesis, diagnosis and treatment of disease.Описан больной 63 лет с рецидивом саркомы Капоши спорадического типа, имеющий противопоказания к проведению цитостатической терапии. Приведены данные литературы по этиологии, патогенезу, диагностике и терапии заболевания

    Cosmological Implications of Neutrinos

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    The lectures describe several cosmological effects produced by neutrinos. Upper and lower cosmological limits on neutrino mass are derived. The role that neutrinos may play in formation of large scale structure of the universe is described and neutrino mass limits are presented. Effects of neutrinos on cosmological background radiation and on big bang nucleosynthesis are discussed. Limits on the number of neutrino flavors and mass/mixing are given.Comment: 41 page, 7 figures; lectures presented at ITEP Winter School, February, 2002; to be published in the Proceeding

    Study of BaTiO₃ ceramics doped with Mn and Ce or Nb and Sr

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    ESR study of BaTiO₃ ferroelectrics doped with cerium or with niobium and strontium, both types of samples being doped with manganese, was performed at room temperature. In the samples of the first type the most intensive line with g-factor 1.9612 was shown to originate from paramagnetic center Ti³⁺–Ce³⁺. The small intensity line was related to Fe³⁺–Vo center, which can be unavoidable impurity in BaTiO₃. In the samples doped with strontium, the six lines intensive spectrum, which corresponds to hyperfine structure of Mn²⁺, was observed. The intensity of the spectrum was shown to decrease with strontium concentration increase. This effect was supposed to be related to the decrease of the grain sizes that results in migration of manganese and, possibly, niobium ions. The influence of these impurities, of their charge states and positions in crystalline lattice of BaTiO₃ on the PTCR effect is discussed.Представлено результати ЕПР досліджень сегнетоелектричної кераміки BaTiO₃ двох серій: легованої церієм та марганцем або ніобієм, стронцієм та марганцем, при кімнатній температурі. Показано, що у зразках першої серії найбільш інтенсивна лінія з g-фактором 1.9612 належить до парамагнітного центру Ti³⁺–Ce³⁺. Лінії малої інтенсивності належать до центру Fe³⁺–Vo (пов’язаного з неконтрольованою домішкою заліза у зразках) та до іону Mn²⁺. В другій серії зразків спостерігався спектр, який відповідає надтонкій структурі іону Mn²⁺. Інтенсивність цього спектру зменшувалась із збільшенням концентрації стронцію. Можливо цей ефект пов’язаний із зменшенням розмірів зерен та міграцією марганцю та, можливо ніобію, у міжзерновий простір. Обговорюється вплив домішок, їх зарядового стану та позиції у кристалічній ґратці на ефект позитивного температурного коефіцієнту опору

    Fast Diffusion Process in Quenched hcp Dilute Solid 3^3He-4^4He Mixture

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    The study of phase structure of dilute 3^3He - 4^4He solid mixture of different quality is performed by spin echo NMR technique. The diffusion coefficient is determined for each coexistent phase. Two diffusion processes are observed in rapidly quenched (non-equilibrium) hcp samples: the first process has a diffusion coefficient corresponding to hcp phase, the second one has huge diffusion coefficient corresponding to liquid phase. That is evidence of liquid-like inclusions formation during fast crystal growing. It is established that these inclusions disappear in equilibrium crystals after careful annealing.Comment: 7 pages, 3 figures, QFS200

    Geotomography with solar and supernova neutrinos

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    We show how by studying the Earth matter effect on oscillations of solar and supernova neutrinos inside the Earth one can in principle reconstruct the electron number density profile of the Earth. A direct inversion of the oscillation problem is possible due to the existence of a very simple analytic formula for the Earth matter effect on oscillations of solar and supernova neutrinos. From the point of view of the Earth tomography, these oscillations have a number of advantages over the oscillations of the accelerator or atmospheric neutrinos, which stem from the fact that solar and supernova neutrinos are coming to the Earth as mass eigenstates rather than flavour eigenstates. In particular, this allows reconstruction of density profiles even over relatively short neutrino path lengths in the Earth, and also of asymmetric profiles. We study the requirements that future experiments must meet to achieve a given accuracy of the tomography of the Earth.Comment: 35 pages, 7 figures; minor textual changes in section

    Study of the effect of neutrino oscillations on the supernova neutrino signal in the LVD detector

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    The LVD detector, located in the INFN Gran Sasso National Laboratory (Italy), studies supernova neutrinos through the interactions with protons and carbon nuclei in the liquid scintillator and interactions with the iron nuclei of the support structure. We investigate the effect of neutrino oscillations in the signal expected in the LVD detector. The MSW effect has been studied in detail for neutrinos travelling through the collapsing star and the Earth. We show that the expected number of events and their energy spectrum are sensitive to the oscillation parameters, in particular to the mass hierarchy and the value of θ13\theta_{13}, presently unknown. Finally we discuss the astrophysical uncertainties, showing their importance and comparing it with the effect of neutrino oscillations on the expected signal.Comment: Accepted for pubblication on Astroparticle Physics. 36 pages, 18 figure
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