14,151 research outputs found
A Proof of Tarski’s Fixed Point Theorem by Application of Galois Connections
Two examples of Galois connections and their dual forms are considered. One
of them is applied to formulate a criterion when a given subset of a complete lattice forms
a complete lattice. The second, closely related to the first, is used to prove in a short way
the Knaster-Tarski’s fixed point theore
Implication of Barrier Fluctuations on the Rate of Weakly Adiabatic Electron Transfer
The problem of escape of a Brownian particle in a cusp-shaped metastable
potential is of special importance in nonadiabatic and weakly-adiabatic rate
theory for electron transfer (ET) reactions. Especially, for the
weakly-adiabatic reactions, the reaction follows an adiabaticity criterion in
the presence of a sharp barrier. In contrast to the non-adiabatic case, the ET
kinetics can be, however considerably influenced by the medium dynamics.
In this paper, the problem of the escape time over a dichotomously
fluctuating cusp barrier is discussed with its relevance to the high
temperature ET reactions in condensed media.Comment: RevTeX 4, 14 pages, 3 figures. To be printed in IJMP C. References
corrected and update
Detection of sodium in the atmosphere of WASP-69b
Transit spectroscopy is one of the most commonly used methods to characterize
exoplanets atmospheres. From the ground, these observations are very
challenging due to the terrestrial atmosphere and its intrinsic variations, but
high-spectral resolution observations overcome this difficulty by resolving the
spectral lines and taking advantage of the different Doppler velocities of the
Earth, the host star and the exoplanet. We analyze the transmission spectrum
around the Na I doublet at 589 nm of the exoplanet WASP-69b, a hot Jupiter
orbiting a K-type star with a period of 3.868 days, and compare the analysis to
that of the well-know hot Jupiter HD 189733b. We also present the analysis of
the Rossiter-McLaughlin effect for WASP-69b. Two transits of WASP-69b were
observed with the HARPS-North spectrograph (R = 115 000) at the TNG telescope.
We perform a telluric contamination subtraction based on the comparison between
the observed spectra and a telluric water model. Then, the common steps of the
differential spectroscopy are followed to extract the transmission spectrum.
The method is tested with archival transit data of the extensively studied
exoplanet HD 189733b, obtained with the HARPS-South spectrograph at ESO 3.6m
telescope, and then applied to WASP-69b data. For HD 189733b, we spectrally
resolve the Na I doublet and measure line contrasts of (D2) and
(D1), and FWHMs of {\AA} (D2) and
{\AA} (D1), in agreement with previously published results. A net
blueshift of {\AA} is measured. For WASP-69b only the contrast of
the D2 line is measured (). Even if this corresponds to a
detection at the -level of excess absorption of in a
passband of {\AA}, more transits are needed to fully characterize the
lines profiles and retrieve accurate atmospheric properties.Comment: 15 pages, 14 figure
The GTC exoplanet transit spectroscopy survey X. Stellar spots versus Rayleigh scattering: the case of HAT-P-11b
Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be
detected from ground or space based telescopes, however, stellar activity in
the form of spots can mimic Rayleigh scattering in the observed transmission
spectrum. Quantifying this phenomena is key to our correct interpretation of
exoplanet atmospheric properties. We obtained long-slit optical spectroscopy of
two transits of HAT-P-11b with the Optical System for Imaging and
low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at Gran Telescopio
Canarias (GTC) on August 30 2016 and September 25 2017. We integrated the
spectrum of HAT-P-11 and one reference star in several spectroscopic channels
across the 400-785 nm region, creating numerous light curves of
the transits. We fit analytic transit curves to the data taking into account
the systematic effects and red noise present in the time series in an effort to
measure the change of the planet-to-star radius ratio
() across wavelength. By fitting both transits
together, we find a slope in the transmission spectrum showing an increase of
the planetary radius towards blue wavelengths. A closer inspection to the
transmission spectrum of the individual data sets reveals that the first
transit presents this slope while the transmission spectrum of the second data
set is flat. Additionally we detect hints of Na absorption in the first night,
but not in the second. We conclude that the transmission spectrum slope and Na
absorption excess found in the first transit observation are caused by
unocculted stellar spots. Modeling the contribution of unocculted spots to
reproduce the results of the first night we find a spot filling factor of
and a spot-to-photosphere temperature difference
of K.Comment: Accepted for publication in Astronomy & Astrophysics, 13 page
The model of cohesion development of metropolitan areas
Artykuł analizuje doświadczenia jednostek samorządu terytorialnego aglomeracji poznańskiej w rozwijaniu różnych form kooperacji. Szczególna uwaga została poświęcona rozpoznaniu i zaprezentowaniu instytucjonalnych form współdziałania na tworzących się metropolitalnych obszarach funkcjonalnych.Badania dotyczące rozwoju form spójności w aglomeracji poznańskiej przedstawiono na tle aktualnej europejskiej polityki ukierunkowanej terytorialnie, kładącej nacisk na wspieranie rozwoju obszarów funkcjonalnych. Specjalna wagę przykłada się w tej polityce do rozwiązywania wyzwań wynikających z narastania powiązań funkcjonalnych na obszarach metropolitalnych. Aktualne działania podejmowane w kształtujących się funkcjonalnych polskich obszarach metropolitalnych są omawiane także w świetle powstającej obecnie polskiej polityki ukierunkowanej terytorialnie. Szczególną uwagę poświęca ona wzmacnianiu współpracy międzysamorządowej oraz kooperacji z innymi sektorami na obszarach funkcjonalnych, ze szczególnym uwzględnieniem obszarów o charakterze metropolitalnym.Efektem badań prezentowanych w artykule jest propozycja modelu budowania spójności w obszarach metropolitalnych. Model uwzględnia zalecenia polityki europejskiej, polskiej i zmieniające się krajowe ramy legislacyjne oraz uwarunkowania i doświadczenia lokalne.he development of various forms of cooperation. Particular attention has been devoted to the recognition and presentation of institutional forms of cooperation in emerging metropolitan functional areas.The results of a research in the development of forms of cohesion in the Poznań agglomeration are shown in the context of the current European territorially oriented development policy that emphasizes supporting the development of functional areas. Special attention is paid to the policyto deal with the challenges arising from increasing functional connections in metropolitan areas. Current activities in the Polish emerging functional metropolitan areas are discussed in light of the currently emerging Polish territorial based policy. The paper draws special attention to the strengthening of cooperation between local authorities and cooperation with other sectors of the functional areas with special emphasis on metropolitan areas.The result of the research presented in the paper is the proposal to build a model of cohesion in metropolitan areas. The model takes into account the recommendations of European and Polish policy, the changing national legislative framework and local conditions and experience
Dynamics and Decay of Heavy-Light Hadrons
Recent signals for narrow hadrons containing heavy and light flavours are
compared with quark model predictions for spectroscopy, strong decays, and
radiative transitions. In particular, the production and identification of
excited charmed and cs states are examined with emphasis on elucidating the
nature of and states. Roughly 200 strong decay amplitudes of
and states up to 3.3 GeV are presented. Applications include determining
flavour content in mesons and the mixing angle in and wave
states and probes of putative molecular states. We advocate searching for
radially excited states in B decays.Comment: 19 pages, 7 figures, revtex. A numerical error is corrected. Some
strong decay rates have change
A preparation of a series of radio scripts on the chief agricultural products grown within the United States of America.
Thesis (M.S.)--Boston Universit
Radiative transitions of and
We study radiative decays of and using
light-cone QCD sum rules. In particular, we consider the decay modes
and and evaluate the hadronic parameters in the transition
amplitudes analyzing correlation functions of scalar, pseudoscalar, vector and
axial-vector quark currents. In the case of
we also consider determinations based on two different correlation functions in
HQET. The decay widths turn out to be different than previous estimates
obtained by other methods; the results favour the interpretation of
and as ordinary mesons.Comment: RevTex, 23 pages, 9 eps figure
Tuning of the spin-orbit interaction in a quantum dot by an in-plane magnetic field
Using an exact diagonalization approach we show that one- and two-electron
InAs quantum dots exhibit avoided crossing in the energy spectra that are
induced by the spin-orbit coupling in the presence of an in-plane external
magnetic field. The width of the avoided crossings depends strongly on the
orientation of the magnetic field which reveals the intrinsic anisotropy of the
spin-orbit coupling interactions. We find that for specific orientations of the
magnetic field avoided crossings vanish. Value of this orientation can be used
to extract the ratio of the strength of Rashba and Dresselhaus interactions.
The spin-orbit anisotropy effects for various geometries and orientations of
the confinement potential are discussed. Our analysis explains the physics
behind the recent measurements performed on a gated self-assembled quantum dot
[S. Takahashi et al. Phys. Rev. Lett. 104, 246801 (2010)].Comment: Corrected according to referees comment
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