112 research outputs found

    Analytic Approximations for Three Neutrino Oscillation Parameters and Probabilities in Matter

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    The corrections to neutrino mixing parameters in the presence of matter of constant density are calculated systematically as series expansions in terms of the mass hierarchy \dm{21}/\dm{31}. The parameter mapping obtained is then used to find simple, but nevertheless accurate formulas for oscillation probabibilities in matter including CP-effects. Expressions with one to one correspondence to the vacuum case are derived, which are valid for neutrino energies above the solar resonance energy. Two applications are given to show that these results are a useful and powerful tool for analytical studies of neutrino beams passing through the Earth mantle or core: First, the ``disentanglement problem'' of matter and CP-effects in the CP-asymmetry is discussed and second, estimations of the statistical sensitivity to the CP-terms of the oscillation probabilities in neutrino factory experiments are presented.Comment: 17 pages, 3 figure

    Atypical suamous papilloma of the conjunctiva

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    Papillomas are benign tumors of human skin and mucous membranes caused by human papillomavirus (HPV). The virus causes abnormal epithelial cell growth. The formations vary in shape, size and location. The conjunctival papillomas are one of the most common benign tumors of the squamous epithelium of the conjunctiva. They rarely undergo malignant transformation. Purpose: To present a clinical case with proven atypical squamous papilloma of the conjunctiva. Materials: 58-year-old patient was admitted to the Eye Clinic of University Alexandrovska hospital for the first time. Methods: A complete ophthalmologic examination, ultrasonography, surgery and pathohistological diagnosis were performed. Results: Thorough excision of the tumor lesion in healthy tissue was performed. The pathological diagnosis revealed atypical squamous papilloma of the conjunctiva. Conclusion: The diagnosis can only be confirmed pathohistologically. A good relationship between ophthalmologist and pathologist is necessary for the successful diagnosis and subsequent treatment

    Limiting the resectability in locally advanced primary or rec urrent carcinoma of the colon

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    Purpose: The terms of ‘unresectable`, ‘inoperable` and ‘incurable` cancer/patient are widely used but not clearly defined and thus subject to significant subjectivity. Where is the limit of ‘resectability` of colorectal cancer - the criteria are variable and not precisely defined yet. Locally advanced lesion may vary from visible intimately adhered to the surrounding tissue, i.e. marginal, ‘border` resectable tumour to one that directly macroscopically engages adjacent critical structures. This paper presents the experience of other foreign authors with their results in the determination of the tumour as resectable or unresectable as well as own clinical experience in this field.Material and methods: The study covered the patients with colorectal cancer who were operated in the Clinic of Surgery during a period of 9 years and retrospectively analyzed.Results: Out of a total of 1051 surgeries on the occasion of colorectal cancer, advanced disease constituted 28,6% or 301 patients. Of them, 52,5% were localized in different parts of the colon. Fifty-eight combined resections were performed as in 7 of them (recurrent tumours) R1 was accomplished, i.e. a non-radical result. A total of 117 cases were assessed intraoperatively as non-radical surgery and palliative procedures were performed such as resections (with or without restoration of the intestinal passage, but in the case of M1), bypass anastomoses, or simple interruption of the passage. .Conclusion: Many of the world`s leading surgical centres adopt the tactics of ‘adequate aggressive behaviour` for locally advanced primary and recurrent colorectal cancer. In determining the reasonable balance between aggressive approach and the so-called meaningless ‘surgical exorbitance` there is strive to adhere to the view that failure to achieve R0-resection planed in such an operation as well as leading performance or a combination of factors such as advanced age, severe co-morbidities, presence of complicated forms of colorectal cancer, urgent intervention and data of generalization of the malignant process undermine the performance of aggressive block removal of tumour formation. However, adequate pre- and intraoperative assessment and surgical experience should avoid ‘exaggerated` intraoperative status of locally advanced tumou

    Normal tension glaucoma – case report

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    Normal tension glaucoma (NTG), reffered to also as low-tension glaucoma, represents a glaucomatous optic neuropathy classified as a type of Primary open angle glaucoma (POAG). It is characterized by a higher tendency of damage to the optic nerve at relatively low levels of intraocular pressure (IOP), as well as asymmetric pathological process in both eyes of the same patient. A number of IOP-independent factors play a significant role in the progression of the disease and often lead to difficulties in diagnosis and optimal therapy in these patients. We report a typical clinical case of a patient with NTG

    Capillary pressure of van der Waals liquid nanodrops

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    The dependence of the surface tension on a nanodrop radius is important for the new-phase formation process. It is demonstrated that the famous Tolman formula is not unique and the size-dependence of the surface tension can distinct for different systems. The analysis is based on a relationship between the surface tension and disjoining pressure in nanodrops. It is shown that the van der Waals interactions do not affect the new-phase formation thermodynamics since the effect of the disjoining pressure and size-dependent component of the surface tension cancel each other.Comment: The paper is dedicated to the 80th anniversary of A.I. Rusano

    Magnus Expansion and Three-Neutrino Oscillations in Matter

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    We present a semi-analytical derivation of the survival probability of solar neutrinos in the three generation scheme, based on the Magnus approximation of the evolution operator of a three level system, and assuming a mass hierarchy among neutrino mass eigenstates. We have used an exponential profile for the solar electron density in our approximation. The different interesting density regions that appear throughout the propagation are analyzed. Finally, some comments on the allowed regions in the solar neutrino parameter space are addressed.Comment: RevTex4 style, 5 pages including 5 figures. Presented at Mexican School of Astrophysics 2002, Guanajuato, Mexico, 31 Jul - 7 Aug 2002. Final version to appear in the Proceedings of IX Mexican Workshop on Particles and Fields Physics Beyond the Standard Model, Colima Col. Mexico, November 17-22, 200

    CP and T violation test in neutrino oscillation

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    We examine how large violation of CP and T is allowed in long base line neutrino experiments. When we attribute only the atmospheric neutrino anomaly to neutrino oscillation we may have large CP violation effect. When we attribute both the atmospheric neutrino anomaly and the solar neutrino deficit to neutrino oscillation we may have a sizable T violation effect proportional to the ratio of two mass differences; it is difficult to see CP violation since we can't ignore the matter effect. We give a simple expression for T violation in the presence of matter.Comment: 12 pages + 2 eps figures, Latex, In order to avoid misunderstanding we have refined our English and rewritten the parts which might be misleading. Several typographical errors are correcte

    CP Violation and Matter Effect in Long Baseline Neutrino Oscillation Experiments

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    We show simple methods how to separate pure CP violating effect from matter effect in long baseline neutrino oscillation experiments with three generations of neutrinos. We give compact formulae for neutrino oscillation probabilities assuming one of the three neutrino masses (presumably tau-neutrino mass) to be much larger than the other masses and the effective mass due to matter effect. Two methods are shown: One is to observe envelopes of the curves of oscillation probabilities as functions of neutrino energy; a merit of this method is that only a single detector is enough to determine the presence of CP violation. The other is to compare experiments with at least two different baseline lengths; this has a merit that it needs only narrow energy range of oscillation data.Comment: 17 pages + 9 eps figures, LaTeX, errors are correcte
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