160 research outputs found
Some breach of the Walles' rule and other peculiarities of the fauna in the Weddell Sea
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
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
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
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
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
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 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
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 -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 GeV
Identified mid-rapidity particle spectra of , , and
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 () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of 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
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
- …