Comparison of the Halpha equivalent width of HII regions in a flocculent and a grand design galaxy: possible evidences for IMF variations

We present here a study of the Halpha equivalent widths of the flocculent galaxy NGC 4395 and the grand design galaxy NGC 5457. A difference between the mean values of the Halpha equivalent widths for the two galaxies has been found. Several hypotheses are presented in order to explain this difference: differences in age, metallicity, star formation rate, photon leakage and initial mass function. Various tests and Monte Carlo models are used to find out the most probable cause of this difference. The resultsshow that the possible cause for the difference could be a variation in the initial mass function. This difference is such that it seems to favor a fraction of more massive stars in the grand design galaxy when compared with the flocculent galaxy. This could be due to a change of the environmental conditions due to a density wave.Comment: 29 pages, 19 figures, accepted for publication in Ap

Про вплив деяких екологічних чинників на інтенсивність фільтрації устриці (Ostrea edulis)

Quantitative regularities of the filtration feeding of the Black Sea oyster depending on some ecological factors were studied. Influence of food concentration on filtration activity of shellfish is described. Dependences of filtration speed are certain on the body mass of oysters under different temperature conditions were found. The seasonal changes of its intensity in the Kerch Strait and the Donuzlav Estuary are illustrated. Influence of water salinity on filtration activity of the oyster is established.Исследованы количественные закономерности питания фильтрации черноморской устрицы в зависимости от ряда экологических факторов. Рассмотрено влияние концентрации пищи на активность фильтрации моллюсков. Определены зависимости скорости фильтрации от массы тела устриц по разным температурным режимам и охарактеризованы сезонные изменения ее интенсивности в Керченском проливе и лимане Донузлав. Установлено влияние солености воды на активность фильтрации этого вида моллюсков.Досліджено закономірності живлення фільтрації чорноморської устриці залежно від низки екологічних чинників. Розглянуто вплив концентрації їжі на активність фільтрації молюсків. Визначено залежності швидкості фільтрації від маси тіла устриць за різними температурними режимами та охарактеризовано сезонні зміни її інтенсивності в Керченській протоці та лимані Донузлав. Установлено вплив солоності води на активність фільтрації цього виду молюсків

Ріст і енергетичний бюджет плоскої устриці (Ostrea edulis) в ранньому онтогенезі

Regularities of growth and dynamics of balance constituents of the energy budget of the flat oyster larvae in development are investigated. It is shown, that the linear growth in early ontogenesis is described by the exponential equation with high accuracy. Parameters of the functions connecting length, height and weight of larvae are defined. The quantitative characteristic of the energy balance elements of oysters larvae is given. It is shown, that during development from a veliger stage to a pediveliger the energy expenditures for growth, metabolism and nutriment assimilation increase more than 10 times. Net efficiency of larvae growth (coefficient К2) varies within 61.6–62.8 % during development, and the magnitude of a specific daily ration of oyster larvae equals 32–35 % of the energy equivalent of body weight.Исследованы закономерности роста и динамики балансовых составляющих энергетического бюджета личинок плоской устрицы в процессе развития. Линейный рост в раннем онтогенезе с высокой точностью описывается экспоненциальным уравнением. Определены параметры функций, связывающих длину с высотой и массой личинок. Дана количественная характеристика элементов энергетического баланса личинок устриц и показано, что при их развитии от стадии велигера до педивелигера траты энергии на рост, метаболизм и ассимиляцию пищи возрастают более чем в 10 раз. Чистая эффективность роста (коэффициент К2) личинок в процессе развития варьирует в пределах 61,6–62,8 %, а величина удельного суточного рациона личинок устрицы составляет 32–35 % от энергетического эквивалента массы тела.Досліджено закономірності росту та динаміки балансових складових енергетичного бюджету личинок плоскої устриці у процесі розвитку. Лінійний ріст у ранньому онтогенезі з високою точністю описується експоненціальним рівнянням. Визначені параметри функцій, що пов’язують довжину з висотою та масою личинок. Надано кількісну характеристику елементів енергетичного балансу личинок устриць і показано, що при їх розвитку від стадії велігера до педівелігера витрати енергії на зростання, метаболізм і асиміляцію зростають більше ніж у 10 разів. Чиста ефективність росту (коефіцієнт К2) личинок у процесі розвитку варіює в межах 61,6–62,8 %, а величина питомого добового раціону личинок устриці складає 32–35 % від енергетичного еквівалента маси тіла.

Signal approximations by shifted Gaussians: a direct approach by finite linear systems

In this paper we consider interpolation problem connected with series by integer shifts of Gaussians. Known approaches for these problems met numerical difficulties. Due to it another method is considered based on finite-rank approximations by linear systems. The main result for this approach is to establish correctness of the finite-rank linear system under consideration. And the main result of the paper is to prove correctness of the finite-rank linear system approximation. For that an explicit formula for the main determinant of the linear system is derived to demonstrate that it is non-zer

Periodic Pattern in the Residual-Velocity Field of OB Associations

An analysis of the residual-velocity field of OB associations within 3 kpc of the Sun has revealed periodic variations in the radial residual velocities along the Galactic radius vector with a typical scale length of lambda=2.0(+/-0.2) kpc and a mean amplitude of fR=7(+/-1) km/s. The fact that the radial residual velocities of almost all OB-associations in rich stellar-gas complexes are directed toward the Galactic center suggests that the solar neighborhood under consideration is within the corotation radius. The azimuthal-velocity field exhibits a distinct periodic pattern in the region 0<l<180 degrees, where the mean azimuthal-velocity amplitude is ft=6(+/-2) km/s. There is no periodic pattern of the azimuthal-velocity field in the region 180<l<360 degrees. The locations of the Cygnus arm, as well as the Perseus arm, inferred from an analysis of the radial- and azimuthal-velocity fields coincide. The periodic patterns of the residual-velocity fields of Cepheids and OB associations share many common features.Comment: 21 page

Generalized discrete Fourier transform on the base of Lagrange and Hermite interpolation formulas

The article offers several generalizations of Discrete Fourier Transfor

On the correctness of finite-rank approximations by series of shifted Gaussians

In this paper we consider interpolation problem connected with series by integer shifts of Gaussians. Known approaches for these problems met numerical difficulties. Due to it another method is considered based on finite-rank approximations by linear systems. The main result for this approach is to establish correctness of the finite-rank linear system under consideratio

One-Dimensional and Multi-Dimensional Integral Transforms of Buschman–Erdélyi Type with Legendre Functions in Kernels

This paper consists of two parts. In the first part we give a brief survey of results on Buschman–Erdélyi operators, which are transmutations for the Bessel singular operator. Main properties and applications of Buschman–Erdélyi operators are outlined. In the second part of the paper we consider multi-dimensional integral transforms of Buschman–Erdélyi type with Legendre functions in kernels. Complete proofs are given in this part, main tools are based on Mellin transform properties and usage of Fox H-functions

On the solvability of equations with a distributed fractional derivative given by the Stieltjes integral

Linear equations in Banach spaces with a distributed fractional derivative given by the Stieltjes integral and with a closed operator A in the right-hand side are considere