160 research outputs found

    Some breach of the Walles' rule and other peculiarities of the fauna in the Weddell Sea

    No full text
    According to the rule of de Candolle-Walles a species diversity decreases from low latitudes regions to high latitudes regions. However in the Weddell Sea the biodiversity of the fauna of some groups are approximately the same (Actiniaria, Mysidacea, Cumacea, Gastropoda, Bryozoa, Echinoidea) or more than this in the Magellan region (Spongia, Pycnogonida, Holothuroidea, Asteroidea, Ohpiuroidea, Ascidiacea). In spite of the rather high species diversity of bivalves in the Weddell Sea, communities where bivalves dominated (like in Arctic seas) practically are absent and average size of gastropods and bivalves is much less than in the Arctic Ocean. Moreover Reptantia from Decapoda crustacean is absent in the Weddell Sea. We will try to explain the reasons of the breach of the Walles rule of the fauna and will try to explain some other peculiarities of the Weddell Sea. For this purpose we will compare the fauna of some groups in the Magellan region and in the Weddell Sea (Table. Number of species of different genera the Magellan Region and in the Weddell Sea).Согласно правилу меридионального изменения разнообразия Декандоля–Уоллеса, разнообразие видов уменьшается от низких широт к высоким. Сравнение фауны моря Уэдделла с фауной соседнего с ним Магелланова района обнаруживает нарушение этого правила для некоторых групп морских донных животных. У актиний, мизид, кумовых раков, брюхоногих моллюсков, мшанок и морских ежей (Actiniaria, Mysidacea, Cumacea, Gastropoda, Bryozoa, Echinoidea) видовое разнообразие в море Уэдделла почти не уступает таковому в Магеллановом р-не, а у губок, морских пауков, голотурий, морских звезд, офиур и асцидий (Spongia, Pycnogonida, Holothuroidea, Asteroidea, Ohpiuroidea, Ascidiacea) оно даже выше, вопреки правилу Уоллеса. Несмотря на довольно высокое разнообразие видов двустворчатых моллюсков в море Уэдделла, сообщества, где двустворки доминируют (как в арктических морях), фактически отсутствуют, а средний размер гастропод и двустворчатых моллюсков – намного меньше, чем в Северном Ледовитом океане. Кроме того, ракообразные из группы Reptantia (Decapoda) в море Уэдделла отсутствуют. Мы попытаемся объяснить причины нарушения правила Декандоля–Уоллеса и некоторые другие особенности фауны моря Уэдделла. С этой целью мы сравним фауну некоторых групп беспозвоночных Магелланова района и моря Уэдделла.Відповідно до правила меридіональної зміни різноманіття Декандоля–Уоллеса, різноманіття видів зменшується від низьких широт до високих. Порівняння фауни моря Уедделла з фауною сусіднього з ним Магелланового району виявляє порушення цього правила для деяких груп морських донних тварин. У актиній, мізид, кумових раків, черевоногих молюсків, мшанок та морських їжаків (Actiniaria, Mysidacea, Cumacea, Gastropoda, Bryozoa, Echinoidea) видове різноманіття в морі Уедделла майже не поступається такому в Магеллановому районі, а у губок, морських павуків, голотурій, морських зірок, офіур і асцидій (Spongia, Pycnogonida, Holothuroidea, Asteroidea, Ohpiuroidea, Ascidiacea) воно навіть вище, всупереч правилу Уоллеса. Попри досить велике різноманіття видів двостворчастих молюсків у морі Уедделла, угруповання, де двостворки домінують (як в арктичних морях), фактично відсутні, а середній розмір гастропод і двостворчастих молюсків набагато менший, аніж у Північному Льодовитому океані. Окрім того, ракоподібні з групи Reptantia (Decapoda) в морі Уедделла відсутні. Ми спробуємо пояснити причини порушення правила Декандоля–Уоллеса та деякі інші особливості фауни моря Уедделла. З цією метою порівняємо фауну деяких груп безхребетних Магелланового району й моря Уедделла

    The Photophysical Properties Investigation of Hybrid Associates of Methylene Blue Molecules with Colloidal CdS Quantum Dots and CdS / Cd(OH)2 "Core-Shell" Systems

    Get PDF
    The spectral properties of associates of methylene blue molecules with colloidal CdS quantum dots and CdS / Cd(OH)2 «core-shell» systems were investigated. It is shown that according to env ironment methylene blue changes its photophysical properties during association. These properties are due to changes of MB structure as a result of oxidation-reduction reactions. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3527

    Spectral Manifestation of Hybrid Association of Zn0.7Sd0.3S Colloidal Quantum Dots with J-Aggregates of Thiacarbocyanine Dye

    Get PDF
    Spectral properties of mixtures of Zn0.7Sd0.3S colloidal quantum dots with mean diameter value of 3.5 nm with the molecules of 3,3'-di(γ-sulfopropil)-9-ethyl-4,5,4',5'-dibenzo-thiacarbocyanine betaine pyridine salt (DEC), prepared in gelatin were investigated. The obtained data indicated that the formation of well-luminescent trans-J-aggregates and spectral tuning in the position of the absorption band of DEC and the luminescence band of quantum dots, providing requirements for resonant energy transfer in the hybrid associate are the determinant factors in the increase of the luminescent emission of DEC molecules, interacting with Zn0.7Cd0.3S colloidal quantum dots. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3532

    Electric field dependence of pairing temperature and tunneling

    Full text link
    Using the Bethe-Salpeter equation including high electric fields, the dependence of the critical temperature of onsetting superconductivity on the applied field is calculated analytically. The critical temperature of pairing is shown to increase with the applied field strength. This is a new field effect and could contribute to the explanation of recent experiments on field induced superconductivity. From the field dependence of the Bethe-Salpeter equation, the two--particle bound state solution is obtained as a resonance with a tunneling probability analogous to the WKB solution of a single particle confined in a potential and coupled to the electrical field.Comment: 4 pages 1 figure, revised version from 29.10.02, Rev. B in pres

    Fock Representations of Quantum Fields with Generalized Statistic

    Full text link
    We develop a rigorous framework for constructing Fock representations of quantum fields obeying generalized statistics associated with certain solutions of the spectral quantum Yang-Baxter equation. The main features of these representations are investigated. Various aspects of the underlying mathematical structure are illustrated by means of explicit examples.Comment: 26 pages, Te

    Anomalous Effects of "Guest" Charges Immersed in Electrolyte: Exact 2D Results

    Full text link
    We study physical situations when one or two "guest" arbitrarily-charged particles are immersed in the bulk of a classical electrolyte modelled by a Coulomb gas of positive/negative unit point-like charges, the whole system being in thermal equilibrium. The models are treated as two-dimensional with logarithmic pairwise interactions among charged constituents; the (dimensionless) inverse temperature β\beta is considered to be smaller than 2 in order to ensure the stability of the electrolyte against the collapse of positive-negative pairs of charges. Based on recent progress in the integrable (1+1)-dimensional sine-Gordon theory, exact formulas are derived for the chemical potential of one guest charge and for the asymptotic large-distance behavior of the effective interaction between two guest charges. The exact results imply, under certain circumstances, anomalous effects such as an effective attraction (repulsion) between like-charged (oppositely-charged) guest particles and the charge inversion in the electrolyte vicinity of a highly-charged guest particle. The adequacy of the concept of renormalized charge is confirmed in the whole stability region of inverse temperatures and the related saturation phenomenon is revised.Comment: 21 pages, 1 figur

    Heavy quarkonium: progress, puzzles, and opportunities

    Get PDF
    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

    Full text link
    Identified mid-rapidity particle spectra of π±\pi^{\pm}, K±K^{\pm}, and p(pˉ)p(\bar{p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (RdAuR_{dAu}) between protons (p+pˉ)(p+\bar{p}) and charged hadrons (hh) in the transverse momentum range 1.2<pT<3.01.2<{p_{T}}<3.0 GeV/c is measured to be 1.19±0.051.19\pm0.05(stat)±0.03\pm0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p+pˉ)/h(p+\bar{p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from transverse momentum 1.8 GeV/c to 3. GeV/

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

    Get PDF
    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC
    corecore