65 research outputs found
Lorentz and CPT Violation in Neutrinos
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)
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™
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"
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
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
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
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 He-He Mixture
The study of phase structure of dilute He - He 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
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
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 , 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
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