Azimuthal modulation of the event rate of cosmic ray extensive air showers by the geomagnetic field

The Earth's magnetic field effect on the azimuthal distribution of extensive air showers (EAS) of cosmic rays has been evaluated using a bulk of the Yakutsk array data. The uniform azimuthal distribution of the EAS event rate is rejected at the significance level 10^(-14). Amplitude of the first harmonics of observed distribution depends on zenith angle as A1=0.2*sin^2(theta) and is almost independent of the primary energy; the phase coincides with the magnetic meridian. Basing upon the value of measured effect, the correction factor has been derived for the particle density depending on a geomagnetic parameter of a shower.Comment: 4 pages, 3 figures in ps file

Государственная поддержка инвестиционных проектов в рамках соглашения о защите и поощрении капиталовложений: методологическое обоснование

The subject of research is economic interactions related to the implementation of an investment project within the framework of an agreement on the protection and promotion of investments (hereinafter referred to as the APCI).Purpose: methodological substantiation of the expediency of providing state support measures to ensure the minimum profitability of an investment project implemented within the framework of the APCI.Objectives: to propose an indicator that reflects the minimum profitability of an investment project, the mechanism for its usage to determine state support measures, additional state support measures in cases where they are not sufficiently established in the legislation.Methods: analysis of approaches to determining the discount rate; statistical (observation, grouping, method of indicators) for calculating industry-specific ROIC values; content analysis to select state support measures.Results: it is proposed to use the ROIC indicator as the minimum profitability of a commercial investment project. The indicator was calculated according to the data of all organizations that are not subjects of medium and small enterprises operating in the period 2012–2021. The sample included 133 organizations that make up eight subclasses of Russian classifier of types of economic activity (pulp and paper production; production of fertilizers and nitrogen compounds; production of pesticides, etc.; production of paints, varnishes, etc.; production of pharmaceutical substances; production of medicines; activities in the field of telecommunications; development of computer software). Based on the data from 1011 observations, the median value of ROIC for each subclass was calculated, the reliability of which is confirmed by the approved minimum rates of return on invested capital for calculating the tariffs of regulated organizations. A mechanism is proposed for using ROIC to determine state support measures within the framework of the APCI, including: determining the median value of ROIC for foreign economic activity, calculating ROIC for an investment project, and determining state support measures by their ratio. As additional measures of state support within the framework of the APCI, it is proposed to establish tax preferences (lower tax rates, tax benefits, tax deductions), as well as accelerated depreciation of fixed assets. The proposed developments create a methodological basis for substantiating the provision of various state support measures within the framework of the APCI.Предмет исследования —  экономические отношения, связанные с осуществлением инвестиционного проекта, реализуемого в рамках соглашения о защите и поощрении капиталовложений (далее —  СЗПК).Цель: методологическое обоснование целесообразности предоставления мер господдержки для обеспечения минимальной доходности инвестиционного проекта, реализуемого в рамках СЗПК.Задачи: предложить показатель, отражающий минимальную доходность инвестиционного проекта, механизм его использования для определения мер господдержки, дополнительные меры господдержки в случае недостаточно установленных в законодательстве.Методы: анализ подходов к определению ставки дисконтирования; статистические (наблюдение, группировка, метод показателей) для расчета отраслевых значений ROIC; контент-анализ для выбора мер господдержки.Результаты: в качестве минимальной доходности коммерческого инвестиционного проекта предложено использовать показатель ROIC. Проведен расчет показателя по данным всех организаций, не являющихся субъектами средних и малых предприятий, функционирующих в период 2012–2021 гг. В выборку вошли 133 организации, составляющие восемь подклассов ОКВЭД (производство целлюлозы и бумаги; производство удобрений и азотных соединений; производство пестицидов и др.; производство красок, лаков и др.; производство фармацевтических субстанций; производство лекарственных препаратов; деятельность в сфере телекоммуникаций; разработка компьютерного программного обеспечения). По данным 1011 наблюдений рассчитано медианное значение ROIC для каждого подкласса, достоверность которого подтверждается утвержденными минимальными нормами доходности инвестированного капитала для расчета тарифов регулируемых организаций. Предложен механизм использования ROIC для определения мер господдержки в рамках СЗПК, включающий: определение медианного значения ROIC по ВЭД, расчет ROIC по инвестиционному проекту, определение мер господдержки по их соотношению. В качестве дополнительных мер господдержки в рамках СЗПК предложено установить налоговые преференции (пониженные налоговые ставки, налоговые льготы, налоговые вычеты), а также использовать ускоренную амортизацию основных средств. Предложенные разработки создают методологическую основу обоснования предоставления различных мер господдержки в рамках СЗПК

The 1986?1989 ENSO cycle in a chemical climate model

International audienceA pronounced ENSO cycle occurred from 1986 to 1989, accompanied by distinct dynamical and chemical anomalies in the global troposphere and stratosphere. Reproducing these effects with current climate models not only provides a model test but also contributes to our still limited understanding of ENSO's effect on stratosphere-troposphere coupling. We performed several sets of ensemble simulations with a chemical climate model (SOCOL) forced with global sea surface temperatures. Results were compared with observations and with large-ensemble simulations performed with an atmospheric general circulation model (MRF9). We focus our analysis on the extratropical stratosphere and its coupling with the troposphere. In this context, the circulation over the North Atlantic sector is particularly important. Observed differences between the El Niño winter 1987 and the La Niña winter 1989 include a negative North Atlantic Oscillation index with corresponding changes in temperature and precipitation patterns, a weak polar vortex, a warm Arctic middle stratosphere, negative and positive total ozone anomalies in the tropics and at middle to high latitudes, respectively, as well as anomalous upward and poleward Eliassen-Palm (EP) flux in the midlatitude lower stratosphere. Most of the tropospheric features are well reproduced in the ensemble means in both models, though the amplitudes are underestimated. In the stratosphere, the SOCOL simulations compare well with observations with respect to zonal wind, temperature, EP flux, and ozone, but magnitudes are underestimated in the middle stratosphere. The polar vortex strength is well reproduced, but within-ensemble variability is too large for obtaining a significant signal in Arctic temperature and ozone. With respect to the mechanisms relating ENSO to stratospheric circulation, the results suggest that both, upward and poleward components of anomalous EP flux are important for obtaining the stratospheric signal and that an increase in strength of the Brewer-Dobson circulation is part of that signal

Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape

We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064 nm pulsed beams propagate from wider (122 µm) into smaller (37 µm) diameter. In the passive mode, increasing the input beam peak power above 20 kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600 nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length

On the Cauchy Problem for the Korteweg-de Vries Equation with Steplike Finite-Gap Initial Data I. Schwartz-Type Perturbations

We solve the Cauchy problem for the Korteweg-de Vries equation with initial conditions which are steplike Schwartz-type perturbations of finite-gap potentials under the assumption that the respective spectral bands either coincide or are disjoint.Comment: 29 page

Long-Time Asymptotics of Perturbed Finite-Gap Korteweg-de Vries Solutions

We apply the method of nonlinear steepest descent to compute the long-time asymptotics of solutions of the Korteweg--de Vries equation which are decaying perturbations of a quasi-periodic finite-gap background solution. We compute a nonlinear dispersion relation and show that the $x/t$ plane splits into $g+1$ soliton regions which are interlaced by $g+1$ oscillatory regions, where $g+1$ is the number of spectral gaps. In the soliton regions the solution is asymptotically given by a number of solitons travelling on top of finite-gap solutions which are in the same isospectral class as the background solution. In the oscillatory region the solution can be described by a modulated finite-gap solution plus a decaying dispersive tail. The modulation is given by phase transition on the isospectral torus and is, together with the dispersive tail, explicitly characterized in terms of Abelian integrals on the underlying hyperelliptic curve.Comment: 45 pages. arXiv admin note: substantial text overlap with arXiv:0705.034

About optimal loss function for training physics-informed neural networks under respecting causality

A method is presented that allows to reduce a problem described by differential equations with initial and boundary conditions to the problem described only by differential equations. The advantage of using the modified problem for physics-informed neural networks (PINNs) methodology is that it becomes possible to represent the loss function in the form of a single term associated with differential equations, thus eliminating the need to tune the scaling coefficients for the terms related to boundary and initial conditions. The weighted loss functions respecting causality were modified and new weighted loss functions based on generalized functions are derived. Numerical experiments have been carried out for a number of problems, demonstrating the accuracy of the proposed methods.Comment: 25 pages, 7 figures, 6 table

Muon content of ultra-high-energy air showers: Yakutsk data versus simulations

We analyse a sample of 33 extensive air showers (EAS) with estimated primary energies above 2\cdot 10^{19} eV and high-quality muon data recorded by the Yakutsk EAS array. We compare, event-by-event, the observed muon density to that expected from CORSIKA simulations for primary protons and iron, using SIBYLL and EPOS hadronic interaction models. The study suggests the presence of two distinct hadronic components, ``light'' and ``heavy''. Simulations with EPOS are in a good agreement with the expected composition in which the light component corresponds to protons and the heavy component to iron-like nuclei. With SYBILL, simulated muon densities for iron primaries are a factor of \sim 1.5 less than those observed for the heavy component, for the same electromagnetic signal. Assuming two-component proton-iron composition and the EPOS model, the fraction of protons with energies E>10^{19} eV is 0.52^{+0.19}_{-0.20} at 95% confidence level.Comment: 8 pages, 3 figures; v2: replaced with journal versio

Real-time observation of multiexcitonic states in ultrafast singlet fission using coherent 2D electronic spectroscopy.

Singlet fission is the spin-allowed conversion of a spin-singlet exciton into a pair of spin-triplet excitons residing on neighbouring molecules. To rationalize this phenomenon, a multiexcitonic spin-zero triplet-pair state has been hypothesized as an intermediate in singlet fission. However, the nature of the intermediate states and the underlying mechanism of ultrafast fission have not been elucidated experimentally. Here, we study a series of pentacene derivatives using ultrafast two-dimensional electronic spectroscopy and unravel the origin of the states involved in fission. Our data reveal the crucial role of vibrational degrees of freedom coupled to electronic excitations that facilitate the mixing of multiexcitonic states with singlet excitons. The resulting manifold of vibronic states drives sub-100 fs fission with unity efficiency. Our results provide a framework for understanding singlet fission and show how the formation of vibronic manifolds with a high density of states facilitates fast and efficient electronic processes in molecular systems.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nchem.237

Laser acceleration of ion beams

We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.Comment: 4 pages, 4 figures, Talk at the Helmholtz International Summer School "Dense Matter in heavy Ion Collisions and Astrophysics", August 21 - September 1, 2006, JINR Dubna, Russia; v2, misprints correcte