Morphological variation and sex dimorphism in adult Аzov Yellow-legged Gull Larus cachinnans сachinnans

Gulls were trapped in the breeding colony on islands of Molochny Liman, a salt reservoir near the north Azov seashore (south of Zaporizhzhia Region, Ukraine). The total of measured cachinnans is 80 birds, more than 3500 nestlings were ringed. For trapped birds a total of 28 parameters were taken (14 metrical and 14 colour features). Blood samples were obtained from the most of the captured birds for further genetical analysis, and pictures were taken to record coloration (colour of eyes, legs, mantle, etc.).Исследования проводились в 2000-2001 гг. на юге Запорожской области, на о-вах Молочного лимана Азовского моря. Сетевыми ловушками типа «цилиндр» было отловлено, прижизненно обследовано и окольцовано 80 экз. взрослых чаек, окольцовано свыше 3500 подросших птенцов. Измерения проводились по 28 параметрам (14 метрических и 14 цветовых). Брались пробы крови из ножной вены для последующего генетического анализа, проведена цветная фотосъемка внешнего вида чаек (окраска глаз, ног, мантии и др.).Дослідження проводилися в 2000-2001 рр. на півдні Запорізької області, на о-вах Молочного лиману Азовського моря. Сітковими пастками типу «циліндр» було виловлено, прижиттєво обстежено та закільцьовано 80 екз. дорослих мартинів, закільцьовано понад 3500 підрослих пташенят. Виміри проводилися згідно з 28 параметрами (14 метричних і 14 колірних). Бралися проби крові з ножною вени для подальшого генетичного аналізу, проведена кольорова фотозйомка зовнішнього вигляду чайок (забарвлення очей, ніг, мантії та ін.)

Upper critical field in dirty two-band superconductors: breakdown of the anisotropic Ginzburg-Landau theory

We investigate the upper critical field in a dirty two-band superconductor within quasiclassical Usadel equations. The regime of very high anisotropy in the quasi-2D band, relevant for MgB$_{2}$, is considered. We show that strong disparities in pairing interactions and diffusion constant anisotropies for two bands influence the in-plane $H_{c2}$ in a different way at high and low temperatures. This causes temperature-dependent $H_{c2}$ anisotropy, in accordance with recent experimental data in MgB$_{2}$. The three-dimensional band most strongly influences the in-plane $H_{c2}$ near $T_{c}$, in the Ginzburg-Landau (GL) region. However, due to a very large difference between the c-axis coherence lengths in the two bands, the GL theory is applicable only in an extremely narrow temperature range near $T_c$. The angular dependence of $H_{c2}$ deviates from a simple effective-mass law even near $T_c$.Comment: 12 pages, 5 figures, submitted to Phys.Rev.

The origin of paramagnetic magnetization in field-cooled YBa2Cu3O7 films

Temperature dependences of the magnetic moment have been measured in YBa_2Cu_3O_{7-\delta} thin films over a wide magnetic field range (5 <= H <= 10^4 Oe). In these films a paramagnetic signal known as the paramagnetic Meissner effect has been observed. The experimental data in the films, which have strong pinning and high critical current densities (J_c ~ 2 \times 10^6 A/cm^2 at 77 K), are quantitatively shown to be highly consistent with the theoretical model proposed by Koshelev and Larkin [Phys. Rev. B 52, 13559 (1995)]. This finding indicates that the origin of the paramagnetic effect is ultimately associated with nucleation and inhomogeneous spatial redistribution of magnetic vortices in a sample which is cooled down in a magnetic field. It is also shown that the distribution of vortices is extremely sensitive to the interplay of film properties and the real experimental conditions of the measurements.Comment: RevTex, 8 figure

Ginzburg-Landau theory of vortices in a multi-gap superconductor

The Ginzburg-Landau functional for a two-gap superconductor is derived within the weak-coupling BCS model. The two-gap Ginzburg-Landau theory is, then, applied to investigate various magnetic properties of MgB2 including an upturn temperature dependence of the transverse upper critical field and a core structure of an isolated vortex. Orientation of vortex lattice relative to crystallographic axes is studied for magnetic fields parallel to the c-axis. A peculiar 30-degree rotation of the vortex lattice with increasing strength of an applied field observed by neutron scattering is attributed to the multi-gap nature of superconductivity in MgB2.Comment: 11 page

Cosmological perturbations in SFT inspired non-local scalar field models

We study cosmological perturbations in models with a single non-local scalar field originating from the string field theory description of the rolling tachyon dynamics. We construct the equation for the energy density perturbations of the non-local scalar field and explicitly prove that for the free field it is identical to a system of local cosmological perturbation equations in a particular model with multiple (maybe infinitely many) local free scalar fields.Comment: 21 pages, no figures, v3: presentation improved, results unchanged, references adde

Every Large Point Set contains Many Collinear Points or an Empty Pentagon

We prove the following generalised empty pentagon theorem: for every integer $\ell \geq 2$, every sufficiently large set of points in the plane contains $\ell$ collinear points or an empty pentagon. As an application, we settle the next open case of the "big line or big clique" conjecture of K\'ara, P\'or, and Wood [\emph{Discrete Comput. Geom.} 34(3):497--506, 2005]