757 research outputs found
Zoo-FISH in the European mole (Talpa europaea) detects all ancestral Boreo-Eutherian human homologous chromosome associations
Zoo-FISH with human whole-chromosome paint probes delineated syntenic association of human homologous chromosome segments 3-21, 14-15, 16-19, 4-8, 7-16 and 12-22 (twice) in the European mole (Talpa europaea, Talpidae, Eulipotyphla, Mammalia). These segment associations represent shared ancestral Boreo-Eutherian traits, half of which were previously not described for Eulipotyphla. The karyotype of the European mole acquired a minimum of 19 translocations and six inversions compared to the presumed Boreo-Eutherian ancestor. Copyright (c) 2006 S. Karger AG, Basel
A Simple Assembly for Carbon Determination in Water
The classical assembly for carbon and hydrogen analysis in
organic compounds was modified for the determination of carbon
in water samples. Numerous analyses of known solutions and of
waste and surface waters containing 5 mg-10 g carbon/I were
performed. The accuracy and reproducibility of results were satisfactory.
The range of applicability is limited by the sensitivity
of the gravimetric determination: on one side and on the other by
the sample volume accessible
The PLATO End-to-End CCD Simulator -- Modelling space-based ultra-high precision CCD photometry for the assessment study of the PLATO Mission
The PLATO satellite mission project is a next generation ESA Cosmic Vision
satellite project dedicated to the detection of exo-planets and to
asteroseismology of their host-stars using ultra-high precision photometry. The
main goal of the PLATO mission is to provide a full statistical analysis of
exo-planetary systems around stars that are bright and close enough for
detailed follow-up studies. Many aspects concerning the design trade-off of a
space-based instrument and its performance can best be tackled through
realistic simulations of the expected observations. The complex interplay of
various noise sources in the course of the observations made such simulations
an indispensable part of the assessment study of the PLATO Payload Consortium.
We created an end-to-end CCD simulation software-tool, dubbed PLATOSim, which
simulates photometric time-series of CCD images by including realistic models
of the CCD and its electronics, the telescope optics, the stellar field, the
pointing uncertainty of the satellite (or Attitude Control System [ACS]
jitter), and all important natural noise sources. The main questions that were
addressed with this simulator were the noise properties of different
photometric algorithms, the selection of the optical design, the allowable
jitter amplitude, and the expected noise budget of light-curves as a function
of the stellar magnitude for different parameter conditions. The results of our
simulations showed that the proposed multi-telescope concept of PLATO can
fulfil the defined scientific goal of measuring more than 20000 cool dwarfs
brighter than mV =11 with a precision better than 27 ppm/h which is essential
for the study of earth-like exo-planetary systems using the transit method.Comment: 5 pages, submitted for the Proceedings of the 4th HELAS International
Conference: Seismological Challenges for Stellar Structur
Massive Superparticle with Tensorial Central Charges
We construct the manifestly Lorenz-invariant formulation of the N=1 D=4
massive superparticle with tensorial central charges. The model contains a real
parameter k and at possesses one -symmetry while at k=0 the
number of -symmetry is two. The equivalence of the formulations at all
is obtained. The local transformations of -symmetry are
written out. It is considered the using of index spinor for construction of the
tensorial central charges. It is obtained the equivalence at classical level
between the massive D=4 superparticle with one -symmetry and the
massive D=4 spinning particleComment: 20 pages, Late
Line-profile variations of stochastically excited oscillations in four evolved stars
Since solar-like oscillations were first detected in red-giant stars, the
presence of non-radial oscillation modes has been debated. Spectroscopic
line-profile analysis was used in the first attempt to perform mode
identification, which revealed that non-radial modes are observable. Despite
the fact that the presence of non-radial modes could be confirmed, the degree
or azimuthal order could not be uniquely identified. Here we present an
improvement to this first spectroscopic line-profile analysis. Aims: We aim to
study line-profile variations of stochastically excited solar-like oscillations
in four evolved stars to derive the azimuthal order of the observed mode and
the surface rotational frequency. Methods: Spectroscopic line-profile analysis
is applied to cross-correlation functions, using the Fourier Parameter Fit
method on the amplitude and phase distributions across the profiles. Results:
For four evolved stars, beta Hydri (G2IV), epsilon Ophiuchi (G9.5III), eta
Serpentis (K0III) and delta Eridani (K0IV) the line-profile variations reveal
the azimuthal order of the oscillations with an accuracy of ~1. Furthermore,
our analysis reveals the projected rotational velocity and the inclination
angle. From these parameters we obtain the surface rotational frequency.
Conclusions: We conclude that line-profile variations of cross-correlation
functions behave differently for different frequencies and that they provide
additional information in terms of the surface rotational frequency and
azimuthal order.Comment: Accepted for publication in Astronomy and Astrophysics, 9 pages, 10
figures and 3 tables. A version with figure 1 in full resolution can be
obtained upon request from first autho
Uniform Twistor-Like Formulation of Massive and Massless Superparticles with Tensorial Central Charges
We construct the manifestly Lorentz-invariant twistorial formulation of N=1
D=4 superparticle with tensorial central charges which describes massive and
massless cases in a uniform manner. The tensorial central charges are realized
in terms of even spinor variables and central charge coordinates. The full
analysis of the number of conserved supersymmetries has been carried out. In
the massive case the superparticle preserves 1/4 or 1/2 of target-space
supersymmetries whereas the massless superparticle preserves two or three
supersymmetries.Comment: LaTex2e file, espcrc2.sty, 7 pages. Based on talk given at the D. V.
Volkov Memorial Conference "Supersymmetry and Quantum Field Theory" (25-29
July, 2000, Kharkov, Ukraine). To be published in Nuclear Physics B
Conference Supplement
An asteroseismic study of the beta Cephei star 12 Lacertae: multisite spectroscopic observations, mode identification and seismic modelling
We present the results of a spectroscopic multisite campaign for the beta
Cephei star 12 (DD) Lacertae. Our study is based on more than thousand
high-resolution high S/N spectra gathered with 8 different telescopes in a time
span of 11 months. In addition we make use of numerous archival spectroscopic
measurements. We confirm 10 independent frequencies recently discovered from
photometry, as well as harmonics and combination frequencies. In particular,
the SPB-like g-mode with frequency 0.3428 1/d reported before is detected in
our spectroscopy. We identify the four main modes as (l1,m1) = (1, 1), (l2,m2)
= (0, 0), (l3,m3) = (1, 0) and (l4,m4) = (2, 1) for f1 = 5.178964 1/d, f2 =
5.334224 1/d, f3 = 5.066316 1/d and f4 = 5.490133 1/d, respectively. Our
seismic modelling shows that f2 is likely the radial first overtone and that
the core overshooting parameter alpha_ov is lower than 0.4 local pressure scale
heights.Comment: 16 pages, 11 figures, accepted in MNRA
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