199 research outputs found

    Graph editing to a given degree sequence

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    We investigate the parameterized complexity of the graph editing problem called Editing to a Graph with a Given Degree Sequence where the aim is to obtain a graph with a given degree sequence σσ by at most k vertex or edge deletions and edge additions. We show that the problem is W[1]-hard when parameterized by k for any combination of the allowed editing operations. From the positive side, we show that the problem can be solved in time 2O(k(Δ+k)2)n2logn2O(k(Δ+k)2)n2log⁡n for n-vertex graphs, where Δ=maxσΔ=maxσ, i.e., the problem is FPT when parameterized by k+Δk+Δ. We also show that Editing to a Graph with a Given Degree Sequence has a polynomial kernel when parameterized by k+Δk+Δ if only edge additions are allowed, and there is no polynomial kernel unless NP⊆coNP/polyNP⊆coNP/poly for all other combinations of allowed editing operations

    Spinless bosons embedded in a vector Duffin-Kemmer-Petiau oscillator

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    Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties with each term of the DKP equation and the proper boundary conditions on the spinors are imposed. It is shown that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The exact solutions for the vector DKP oscillator (nonminimal vector coupling with a linear potential which exhibits an equally spaced energy spectrum in the weak-coupling limit) for spin-0 bosons are presented in a closed form and it is shown that the spectrum exhibits an accidental degeneracy

    Changes in the middle and upper atmosphere parameters during the January 2013 sudden stratospheric warming

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    We present the results of complex obser-vations of various parameters of the middle and upper atmosphere over Siberia in December 2012 – January 2013, during a major sudden stratospheric warming (SSW) event. We analyze variations in ozone concentration from microwave measurements, in stratosphere and lower mesosphere temperatures from lidar and satellite measurements, in the F2-layer critical frequency (foF2), in the total electron content (TEC), as well as in the ratio of concentrations of atomic oxygen to molecular nitrogen (O/N2) in the thermosphere. To interpret the observed disturbances in the upper atmosphere, the experimental measurements are compared with the results of model calculations obtained with the Global Self-consistent Model of Thermosphere—Ionosphere—Protonosphere (GSM TIP). The response of the upper atmosphere to the SSW event is shown to be a decrease in foF2 and TEC during the evolution of the warming event and a prolonged increase in O/N2, foF2, and TEC after the SSW maximum. For the first time, we observe the relation between the increase in stratospheric ozone, thermospheric O/N2, and ionospheric electron density for a fairly long time (up to 20 days) after the SSW maximum at midlatitudes

    Сравнительный анализ орофарингеальной микробиоты у больных хронической обструктивной болезнью легких и бронхиальной астмой различной степени тяжести

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    Backgraund: The result of comparative study of oropharyngeal microbiota taxonomic composition in patients with different severity level of bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD) is presented in this paper. Aims: To compare oropharyngeal microbiota composition in case of bronchial asthma and chronic obstructive pulmonary disease in different severity levels. Metods: 138 patients, 50 with BA and 88 with COPD were studied. For each patient was collected anamnesis vitae, swab from the back of the throat and performed physical examination. High-throughput 16S ribosomal RNA gene sequencing and bioinformatic analysis was employed to characterize the microbial communities. Results: As a result of the study was found a number of differences on various taxonomic levels in microbiota’s composition within group of patients with different severity level of BA and group of patients with different severity level of COPD and between those groups. COPD patients with GOLD 1–2 in comparison with GOLD 3–4 patiens are marked by prevalence of species Brevibacterium aureum, genus Scardovia, Coprococcus, Haemophilus, Moryella, Dialister, Paludibacter and decrease of Prevotella melaninogenica species. BA patients with severe uncontrolled asthma in comparison with patients which have mild persistent asthma are marked by decrease of Prevotella and increase of species Bifidobacterium longum, Prevotella nanceiensis, Neisseria cinerea, Aggregatibacter segnis and genus Odoribacter, Alloiococcus, Lactobacillus, Megasphaera, Parvimonas, Sneathia. Patient’s microbiota in BA group in comparison with COPD group is characterized by the prevalence of Prevotella melaninogenica and genus Selenomonas, Granulicatella и Gemella, and decrease of Prevotella nigrescens, Haemophilus influenza and genus Aggregatibacter, Alloiococcus, Catonella, Mycoplasma, Peptoniphilus и Sediminibacterium. There are no differences between microbiota composition in case of severe uncontrolled BA and very severe COPD. Conclusion: Lack of differences in oropharyngeal microbiota taxonomic composition between patients with severe uncontrolled BA and very severe COPD allow us to suggest a similarity of bronchopulmonary system condition in case of diseases' severe stages.Обоснование. Характеристика орофарингеальной микробиоты при хронической обструктивной болезни легких (ХОБЛ) и бронхиальной астме (БА) в зависимости от тяжести течения заболеваний является актуальной задачей, решение которой позволит уточнить роль микробиоты в их патогенезе. Цель исследования: сравнительный анализ состава орофарингеальной микробиоты при ХОБЛ и БА разной степени выраженности симптомов. Методы. В исследование включены 138 больных, из них 88 с ХОБЛ, 50 — с БА. Для каждого пациента был собран анамнез жизни, проведено физикальное исследование и получен мазок из орофарингеальной области. Определение таксономического состава проводилось секвенированием генов бактериальной 16S рРНК с последующим биоинформатическим и статистическим анализом. Результаты. При сравнительном анализе были найдены различия в представленности микроорганизмов. Для микробиоты больных ХОБЛ 1–2-й степени тяжести в сравнении с образцами ХОБЛ 3–4-й степени на фоне снижения представленностиPrevotella melaninogenica характерно более высокое содержание Brevibacterium aureum и представителей рода Scardovia, Coprococcus, Haemophilus, Moryella, Dialister и Paludibacter. Микробиота пациентов с тяжелой БА в сравнении с таковой при легкой персистирующей форме на фоне более низкого содержания бактерий рода Prevotella характеризуется более выраженным присутствием Bifidobacterium longum, Prevotella nanceiensis, Neisseria cinerea, Aggregatibacter segnis, а также представителей рода Odoribacter, Alloiococcus, Lactobacillus, Megasphaera, Parvimonas и Sneathia. При сравнении микробиоты больных БА и ХОБЛ для пациентов с БА отмечалась более высокая представленность P. melaninogenica и микроорганизмов рода Selenomonas, Granulicatella, Gemella, а также снижение Prevotella nigrescens, Haemophilus influenzae и Aggregatibacter, Alloiococcus, Catonella, Mycoplasma, Peptoniphilus, Sediminibacterium. При этом различия в составе орофарингеальной микробиоты у больных тяжелой неконтролируемой БА и ХОБЛ очень тяжелого течения не выявлены.Заключение. Отсутствие различий в бактериальной композиции орофарингеальной микробиоты у больных с тяжелыми формами ХОБЛ и БА позволяет высказать предположение о сходстве состояния бронхолегочной системы при тяжелых стадиях развития данных заболеваний

    Approximate solution of the Duffin-Kemmer-Petiau equation for a vector Yukawa potential with arbitrary total angular momenta

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    The usual approximation scheme is used to study the solution of the Duffin-Kemmer-Petiau (DKP) equation for a vector Yukawa potential in the framework of the parametric Nikiforov-Uvarov (NU) method. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for arbitrary total angular momentum in closed form. Further, the approximate energy equation and wave function spinor components are also given for case. A set of parameter values is used to obtain the numerical values for the energy states with various values of quantum levelsComment: 17 pages; Communications in Theoretical Physics (2012). arXiv admin note: substantial text overlap with arXiv:1205.0938, and with arXiv:quant-ph/0410159 by other author

    New precise determination of the \tau lepton mass at KEDR detector

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    The status of the experiment on the precise τ\tau lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the τ+τ\tau^+\tau^- cross section behaviour around the production threshold. The preliminary result based on 6.7 pb1^{-1} of data is mτ=1776.800.23+0.25±0.15m_{\tau}=1776.80^{+0.25}_{-0.23} \pm 0.15 MeV. Using 0.8 pb1^{-1} of data collected at the ψ\psi' peak the preliminary result is also obtained: ΓeeBττ(ψ)=7.2±2.1\Gamma_{ee}B_{\tau\tau}(\psi') = 7.2 \pm 2.1 eV.Comment: 6 pages, 8 figures; The 9th International Workshop on Tau-Lepton Physics, Tau0

    Measurement of \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-) and \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)

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    The products of the electron width of the J/\psi meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations \Gamma_{ee}\times(\Gamma_{ee}+\Gamma_{\mu\mu})/\Gamma=(0.6641\pm0.0082\pm0.0100) keV, \Gamma_{ee}/\Gamma_{\mu\mu}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming e\mu universality and using the world average value of the lepton branching fraction, we also determine the leptonic \Gamma_{ll}=5.59\pm0.12 keV and total \Gamma=94.1\pm2.7 keV widths of the J/\psi meson.Comment: 7 pages, 6 figure

    Search for narrow resonances in e+ e- annihilation between 1.85 and 3.1 GeV with the KEDR Detector

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    We report results of a search for narrow resonances in e+ e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width of a narrow resonance Gamma(R -> ee) Br(R -> hadr) < 120 eV has been obtained (at 90 % C.L.)

    Measurement of main parameters of the \psi(2S) resonance

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    A high-precision determination of the main parameters of the \psi(2S) resonance has been performed with the KEDR detector at the VEPP-4M e^{+}e^{-} collider in three scans of the \psi(2S) -- \psi(3770) energy range. Fitting the energy dependence of the multihadron cross section in the vicinity of the \psi(2S) we obtained the mass value M = 3686.114 +- 0.007 +- 0.011 ^{+0.002}_{-0.012} MeV and the product of the electron partial width by the branching fraction into hadrons \Gamma_{ee}*B_{h} = 2.233 +- 0.015 +- 0.037 +- 0.020 keV. The third error quoted is an estimate of the model dependence of the result due to assumptions on the interference effects in the cross section of the single-photon e^{+}e^{-} annihilation to hadrons explicitly considered in this work. Implicitly, the same assumptions were employed to obtain the charmonium leptonic width and the absolute branching fractions in many experiments. Using the result presented and the world average values of the electron and hadron branching fractions, one obtains the electron partial width and the total width of the \psi(2S): \Gamma_{ee} =2.282 +- 0.015 +- 0.038 +- 0.021 keV, \Gamma = 296 +- 2 +- 8 +- 3 keV. These results are consistent with and more than two times more precise than any of the previous experiments
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