636 research outputs found
Robust Subnanometric Plasmon Ruler by Rescaling of the Nonlocal Optical Response
We present the optical response of two interacting metallic nanowires calculated for separation
distances down to angstrom range. State-of-the-art local and nonlocal approaches are compared with
full quantum time-dependent density functional theory calculations that give an exact account of nonlocal
and tunneling effects. We find that the quantum results are equivalent to those from classical approaches
when the nanoparticle separation is defined as the separation between centroids of the screening charges.
This establishes a universal plasmon ruler for subnanometric distances. Such a ruler not only impacts the
basis of many applications of plasmonics, but also provides a robust rule for subnanometric metrology
Wave packet propagation study of the charge transfer interaction in the F^- -Cu(111) and -Ag(111) systems
The electron transfer between an ion and and
surfaces is studied by the wave packet propagation method in order to determine
specifics of the charge transfer interaction between the negative ion and the
metal surface due to the projected band gap. A new modeling of the ion
is developed that allows one to take into account the six quasi-equivalent
electrons of which are {\it a priori} active in the charge transfer
process. The new model invokes methods of constrained quantum dynamics. The
six-electron problem is transformed to two one-electron problems linked via a
constraint. The projection method is used to develop a wave packet propagation
subject to the modeling constraint. The characteristics (energy and width) of
the ion ion level interacting with the two surfaces are determined and
discussed in connection with the surface projected band gap.Comment: 34 pages, Revtex, 9 figures (postscript
The wave packet propagation using wavelets
It is demonstrated that the wavelets can be used to considerably speed up
simulations of the wave packet propagation in multiscale systems. Extremely
high efficiency is obtained in the representation of both bound and continuum
states. The new method is compared with the fast Fourier algorithm. Depending
on ratios of typical scales of a quantum system in question, the wavelet method
appears to be faster by a few orders of magnitude.Comment: Latex 7 pages, 3 colored figures (Fig1 postscript, Fig2,3 gif) in
files separate from the pape
ХЕМИЛЮМИНЕСЦЕНТНАЯ И ЭНЗИМАТИЧЕСКАЯ АКТИВНОСТЬ НЕЙТРОФИЛЬНЫХ ГРАНУЛОЦИТОВ У БОЛЬНЫХ РАСПРОСТРАНЕННЫМ ГНОЙНЫМ ПЕРИТОНИТОМ В ЗАВИСИМОСТИ ОТ ИСХОДА ЗАБОЛЕВАНИЯ
Background: Aim was to study the chemiluminescent activity and the activity of NAD- and NADP-dependent dehydrogenases of neutrophilsdepending on the outcome of the widespread purulent peritonitis (WPP). Patients and methods: 51 patients with a mean age of RSE 54,2±19,2 years were observed. As a control 75 healthy people of similar age range were examined. Lucigenin- and luminol-dependent chemiluminescence activity and activity of NAD(P)-dependent dehydrogenases peripheral blood neutrophils were studied. Results: In patients with a favorable outcome of WPP the maximum intensity increased and the magnitude of the activation index of lucigenine-dependent spontaneous chemiluminescence reduced.Regardless to the outcome of WPP in patients with increased activation index and maxima of the luminol-dependent spontaneous and zymosaninduced chemiluminescence. At the unfavorable outcome of the disease in neutrophils NAD- dependent isositrate dehydrogenase and anaerobic lactate dehydrogenase reaction activity increased. Regardless to the outcome WPP in patients neutrophils aerobic reaction of lactate dehydrogenase, glucose-6-phosphate dehydrogenase and NADP-dependent glutamate dehydrogenase activity reduced but levels of NADH-dependent reaction of malate dehydrogenase, NADH-dependent glutamate dehydrogenase and NADP-dependent isocitrate dehydrogenase activity increased. Conclusion: With the reduction of the intensity of plastic processes and imbalances enzymatic activity in nitrogen metabolism in patients with WPP at unfavorable outcome of the disease increases the activity of enzymes that characterize the level of anaerobic and aerobic respiration. In the absence of marked changes in the activity of enzymes that characterize the level of energy processes in cells of patients with favorable outcome of the WPP, increases the intensity of spontaneous lucigenin-dependent chemiluminescence and reduced neutrophil activation index.Цель исследования: изучить хемилюминесцентную активность и активность НАД- и НАДФ-зависимых дегидрогеназ нейтрофильных гранулоцитов в зависимости от исхода распространенного гнойного перитонита (РГП). Пациенты и методы: обследован 51 больной РГП (средний возраст 54,2±19,2 года). В качестве контроля обследовано 75 здоровых людей аналогичного возрастного диапазона. Изучены показатели люцигенин- и люминолзависимой хемилюминесцентной активности и уровни активности НАДФ-зависимых дегидрогеназ нейтрофильных гранулоцитов периферической крови. Результаты: у больных с благоприятным исходом РГП повышается максимальная интенсивность и снижена величина индекса активации люцигенинзависимой спонтанной хемилюминесценции. Независимо от исхода РГП у больных повышаются индекс активации и максимумы интенсивности люминолзависимой спонтанной и зимозаниндуцированной хемилюминесценции. При неблагоприятном исходе заболевания в нейтрофилах повышена активность НАД-зависимой изоцитратдегидрогеназы и анаэробной реакции лактатдегидрогеназы. Вне зависимости от исхода РГП в нейтрофильных гранулоцитах больных снижена активность аэробной реакции лактатдегидрогеназы, глюкозо-6-фосфатдегидрогеназы и НАДФ-зависимой глутаматдегидрогеназы, но повышены уровни активности НАДН-зависимой реакции малатдегидрогеназы, НАДН-зависимой глутаматдегидрогеназы и НАДФ-зависимой изоцитратдегидрогеназы. Выводы: на фоне снижения интенсивности пластических процессов и дисбаланса ферментативной активности в азотистом обмене у больных РГП при неблагоприятном исходе заболевания повышается активность ферментов, характеризующих уровень анаэробного и аэробного дыхания. При отсутствии выраженных изменений активности ферментов, характеризующих уровень энергетических процессов в клетках у больных РГП при благоприятном исходе заболевания, повышается интенсивность спонтанной люцигенинзависимой хемилюминесценции и снижается индекс активации нейтрофилов
An application of interpolating scaling functions to wave packet propagation
Wave packet propagation in the basis of interpolating scaling functions (ISF)
is studied. The ISF are well known in the multiresolution analysis based on
spline biorthogonal wavelets. The ISF form a cardinal basis set corresponding
to an equidistantly spaced grid. They have compact support of the size
determined by the underlying interpolating polynomial that is used to generate
ISF. In this basis the potential energy matrix is diagonal and the kinetic
energy matrix is sparse and, in the 1D case, has a band-diagonal structure. An
important feature of the basis is that matrix elements of a Hamiltonian are
exactly computed by means of simple algebraic transformations efficiently
implemented numerically. Therefore the number of grid points and the order of
the underlying interpolating polynomial can easily be varied allowing one to
approach the accuracy of pseudospectral methods in a regular manner, similar to
high order finite difference methods. The results of numerical simulations of
an H+H_2 collinear collision show that the ISF provide one with an accurate and
efficient representation for use in the wave packet propagation method.Comment: plain Latex, 11 pages, 4 figures attached in the JPEG forma
Euler configurations and quasi-polynomial systems
In the Newtonian 3-body problem, for any choice of the three masses, there
are exactly three Euler configurations (also known as the three Euler points).
In Helmholtz' problem of 3 point vortices in the plane, there are at most three
collinear relative equilibria. The "at most three" part is common to both
statements, but the respective arguments for it are usually so different that
one could think of a casual coincidence. By proving a statement on a
quasi-polynomial system, we show that the "at most three" holds in a general
context which includes both cases. We indicate some hard conjectures about the
configurations of relative equilibrium and suggest they could be attacked
within the quasi-polynomial framework.Comment: 21 pages, 6 figure
Systems of Hess-Appel'rot type
We construct higher-dimensional generalizations of the classical
Hess-Appel'rot rigid body system. We give a Lax pair with a spectral parameter
leading to an algebro-geometric integration of this new class of systems, which
is closely related to the integration of the Lagrange bitop performed by us
recently and uses Mumford relation for theta divisors of double unramified
coverings. Based on the basic properties satisfied by such a class of systems
related to bi-Poisson structure, quasi-homogeneity, and conditions on the
Kowalevski exponents, we suggest an axiomatic approach leading to what we call
the "class of systems of Hess-Appel'rot type".Comment: 40 pages. Comm. Math. Phys. (to appear
A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses
We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
Search for charginos in e+e- interactions at sqrt(s) = 189 GeV
An update of the searches for charginos and gravitinos is presented, based on
a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector
in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was
found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a
centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by
combining the chargino searches with neutralino searches at the Z resonance
implies a limit on the mass of the lightest neutralino which, for a heavy
sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure
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