The role of the North Atlantic Oscillation in controlling U.K. butterfly population size and phenology

Copyright @ 2012 The Authors. This article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.1. The North Atlantic Oscillation (NAO) exerts considerable control on U.K. weather. This study investigates the impact of the NAO on butterfly abundance and phenology using 34 years of data from the U.K. Butterfly Monitoring Scheme (UKBMS). 2. The study uses a multi-species indicator to show that the NAO does not affect overall U.K. butterfly population size. However, the abundance of bivoltine butterfly species, which have longer flight seasons, were found to be more likely to respond positively to the NAO compared with univoltine species, which show little or a negative response. 3. A positive winter NAO index is associated with warmer weather and earlier flight dates for Anthocharis cardamines (Lepidoptera: Pieridae), Melanargia galathea (Lepidoptera: Nymphalidae), Aphantopus hyperantus (Lepidoptera: Nymphalidae), Pyronia tithonus (Lepidoptera: Nymphalidae), Lasiommata megera (Lepidoptera: Nymphalidae) and Polyommatus icarus (Lepidoptera: Lycaenidae). In bivoltine species, the NAO affects the phenology of the first generation, the timing of which indirectly controls the timing of the second generation. 4. The NAO influences the timing of U.K. butterfly flight seasons more strongly than it influences population size.This study was supported by a multi-agency consortium led by the U.K. Department for Environment, Food and Rural Affairs (Defra), including the Countryside Council for Wales, the Joint Nature Conservation Committee, the Forestry Commission, Natural England, the Natural Environment Research Council, the Northern Ireland Environment Agency and Scottish Natural Heritage. This article is made available through the Brunel Open Access Publishing Fund

Layering in the Ising model

We consider the three-dimensional Ising model in a half-space with a boundary field (no bulk field). We compute the low-temperature expansion of layering transition lines

The gravitationally lensed, luminous infrared galaxy IRAS F10214+4724 observed with XMM-Newton

We report on a short XMM-Newton observation of the gravitationally-lensed, luminous infrared galaxy IRAS F10214+4724 at z=2.3. A faint X-ray source is detected at 4 sigma. The observed 0.5-2 keV (1.7-6.6 keV in the rest-frame) flux is 1.3e-15 erg/s/cm2 and the spectral slope in the rest-frame 1-10 keV band is Gamma~2. These results agree with those obtained from the Chandra X-ray Observatory, given the large uncertainties in both measurements. While possible evidence for excess emission above 5 keV is seen, we suspect this excess might be either spurious or not related to the infrared galaxy.Comment: 4 pages, 2 figures, New Astronomy in pres

Сравнительное исследование регенерации у губок (Porifera)

International audiencet is well known that sponges have unusually high regenerative abilities, which are often associated with their low tissue organization and high dynamics of cell differentiation. In order to identify the diversity of morphogenesis and cellular mechanisms involved in the restoration processes in Porifera, we carried out a detailed comparative study of the regeneration of a number of sponge species from phylogenetically deleted taxa that differ in their anatomical and histological organization. The objects of this project were sponges from the classes Demospongiae, Homoscleromorpha, and Calcarea, which have the leukonoid, siconoid, and asconoid types of the aquiferous system e-mines, as well as different degrees of epithelial development. The main mechanism for the regeneration of leukonoid Demospongiae is the epithelio-mesenchymal transformation involving polypotent archaeocyte cells. Epithelial morphogenesis and cell transdifferentiation are the basis for the regeneration of leukoid Homoscleromorpha and siconoid and asconoid Calcarea. Asconoid Calcarea regeneration is a rare example of “pure” morphallaxis. We have shown that the morphogenetic processes detected in sponges are as complex and diverse as in other higher animals. Thus, sponges can be a source of important information that will allow us to better understand the early evolution of molecular and cellular mechanisms of morphogenesis in animals.2 СПбГУ, биологический факультет 3 МГУ им. Ломоносова, биологический факультет, Беломорская биологическая станция им. Н.А. Перцова Хорошо известно, что губки обладают необычайно высокими регенерационными сп о-собностями что часто связывают с их низкой тканевой организацией и высокой динамикой клеточной дифференцировки. Для того, чтобы выявить разнообразие морфогенезов и клеточ-ных механизмов вовлеченных в восстановительные процессы у Porifera, нами было предпр и-нято детальное сравнительное исследование регенерации ряда видов губок из филогенетич е-ски удаленных таксонов, отличающиеся анатомической и гистологической организацией. Объектами данного проекта послужили губки из классов Demospongiae, Homoscleromorpha и Calcarea, обладающие лейконоидной, сиконоидной и асконоидной типами водоносной сист е-мы, а также разной степенью развития эпителия. Основным механизмом регенерации лейко-ноидных Demospongiae является эпителио-мезенхимная трансформация с вовлечением поли-потентных клеток-археоцитов. Основой регенерации лейконоидных Homoscleromorpha и сиконоидных и асконоидных Calcarea служат эпителиальные морфогенезы и трансдифферен-цировка клеток. Регенерация асконоидных Calcarea представляет собой редкий пример «чи-стого» морфаллаксиса. Мы показали, что морфогенетические процессы, выявленные у губок, являются столь же сложными и разнообразными, как и у других высших животных. Таким образом, губки могут быть источником важной информации, которая позволит нам глубже понять раннюю эволюцию молекулярных и клеточных механизмов морфогенеза у животных. Благодарности Данная работа осуществлена при финансовой поддержке грантов РФФИ № 16-04-00084, и РНФ № 17-14-01089.-8

A geometric discretisation scheme applied to the Abelian Chern-Simons theory

We give a detailed general description of a recent geometrical discretisation scheme and illustrate, by explicit numerical calculation, the scheme's ability to capture topological features. The scheme is applied to the Abelian Chern-Simons theory and leads, after a necessary field doubling, to an expression for the discrete partition function in terms of untwisted Reidemeister torsion and of various triangulation dependent factors. The discrete partition function is evaluated computationally for various triangulations of $S^3$ and of lens spaces. The results confirm that the discretisation scheme is triangulation independent and coincides with the continuum partition functionComment: 27 pages, 5 figures, 6 tables. in late

Charge Fluctuations and Counterion Condensation

We predict a condensation phenomenon in an overall neutral system, consisting of a single charged plate and its oppositely charged counterions. Based on the ``two-fluid'' model, in which the counterions are divided into a ``free'' and a ``condensed'' fraction, we argue that for high surface charge, fluctuations can lead to a phase transition in which a large fraction of counterions is condensed. Furthermore, we show that depending on the valence, the condensation is either a first-order or a smooth transition.Comment: 16 pages, 1 figure, accepted to be published in PR

Counterion Condensation and Fluctuation-Induced Attraction

We consider an overall neutral system consisting of two similarly charged plates and their oppositely charged counterions and analyze the electrostatic interaction between the two surfaces beyond the mean-field Poisson-Boltzmann approximation. Our physical picture is based on the fluctuation-driven counterion condensation model, in which a fraction of the counterions is allowed to ``condense'' onto the charged plates. In addition, an expression for the pressure is derived, which includes fluctuation contributions of the whole system. We find that for sufficiently high surface charges, the distance at which the attraction, arising from charge fluctuations, starts to dominate can be large compared to the Gouy-Chapmann length. We also demonstrate that depending on the valency, the system may exhibit a novel first-order binding transition at short distances.Comment: 15 pages, 8 figures, to appear in PR

Non-Abelian Vortices, Super-Yang-Mills Theory and Spin(7)-Instantons

We consider a complex vector bundle E endowed with a connection A over the eight-dimensional manifold R^2 x G/H, where G/H = SU(3)/U(1)xU(1) is a homogeneous space provided with a never integrable almost complex structure and a family of SU(3)-structures. We establish an equivalence between G-invariant solutions A of the Spin(7)-instanton equations on R^2 x G/H and general solutions of non-Abelian coupled vortex equations on R^2. These vortices are BPS solitons in a d=4 gauge theory obtained from N=1 supersymmetric Yang-Mills theory in ten dimensions compactified on the coset space G/H with an SU(3)-structure. The novelty of the obtained vortex equations lies in the fact that Higgs fields, defining morphisms of vector bundles over R^2, are not holomorphic in the generic case. Finally, we introduce BPS vortex equations in N=4 super Yang-Mills theory and show that they have the same feature.Comment: 14 pages; v2: typos fixed, published versio

The hyperon-nucleon interaction: conventional versus effective field theory approach

Hyperon-nucleon interactions are presented that are derived either in the conventional meson-exchange picture or within leading order chiral effective field theory. The chiral potential consists of one-pseudoscalar-meson exchanges and non-derivative four-baryon contact terms. With regard to meson-exchange hyperon-nucleon models we focus on the new potential of the Juelich group, whose most salient feature is that the contributions in the scalar--isoscalar (\sigma) and vector--isovector (\rho) exchange channels are constrained by a microscopic model of correlated \pi\pi and KKbar exchange.Comment: 28 pages, 8 figures, submitted to Lecture Notes in Physic

Instantons and Yang-Mills Flows on Coset Spaces

We consider the Yang-Mills flow equations on a reductive coset space G/H and the Yang-Mills equations on the manifold R x G/H. On nonsymmetric coset spaces G/H one can introduce geometric fluxes identified with the torsion of the spin connection. The condition of G-equivariance imposed on the gauge fields reduces the Yang-Mills equations to phi^4-kink equations on R. Depending on the boundary conditions and torsion, we obtain solutions to the Yang-Mills equations describing instantons, chains of instanton-anti-instanton pairs or modifications of gauge bundles. For Lorentzian signature on R x G/H, dyon-type configurations are constructed as well. We also present explicit solutions to the Yang-Mills flow equations and compare them with the Yang-Mills solutions on R x G/H.Comment: 1+12 page