1,415 research outputs found
Lie algebras and 3-transpositions
We describe a construction of an algebra over the field of order 2 starting
from a conjugacy class of 3-transpositions in a group. In particular, we
determine which simple Lie algebras arise by this construction. Among other
things, this construction yields a natural embedding of the sporadic simple
group \Fi{22} in the group .Comment: 23 page
Practical, reliable and inexpensive assay of lycopene in tomato products based on the combined use of light emitting diode (LED) and the optothermal window
Light emitting diode (LED) combined with the concept of optothermal window (OW) is proposed as a new approach (LED-OW) to detect lycopene in a wide range of tomato-based products (tomato juice, tomato ketchup, tomato passata and tomato puree). Phytonutrient lycopene is a dominant antioxidant in these products while beta-carotene is present in significantly lower quantities. Therefore for all practical reasons the interfering effect of beta-carotene at 502 nm analytical wavelength can be neglected. The LED-OW method is low-cost and simple, yet accurate and precise. The major attributes of the new method are its rapid speed of response and the fact that no preparation whatsoever of the sample is needed before the analysis. The lycopene found in tomato products studied here varies from 8 mg/100 g to 60 mg/100 g fresh product. Results obtained by LED-OW method were compared to the outcome of conventional, time consuming spectrophotometric methods and the correlation was very good (R = 0.98). Precision of the LED-OW instrumental setup ranged from 0.5 to 7.4%; the RSD achieved for lycopene-richest samples (= 40 mg/100 g) did not exceed 1.7%. Repeatability of analysis by LED-OW was found to vary between 0.7 and 7.1%
Eliminating the low-mass axigluon window
Using recent collider data, especially on the hadronic width the Z0, we
exclude axigluons in the currently allowed low-mass window, namely axigluons in
the mass range 50 GeV < M_A < 120 GeV. Combined with hadron collider data from
di-jet production, axigluons with masses below roughly 1 TeV are now completely
excluded.Comment: 8 pages, no figures, LaTe
Automated supervised classification of variable stars I. Methodology
The fast classification of new variable stars is an important step in making
them available for further research. Selection of science targets from large
databases is much more efficient if they have been classified first. Defining
the classes in terms of physical parameters is also important to get an
unbiased statistical view on the variability mechanisms and the borders of
instability strips. Our goal is twofold: provide an overview of the stellar
variability classes that are presently known, in terms of some relevant stellar
parameters; use the class descriptions obtained as the basis for an automated
`supervised classification' of large databases. Such automated classification
will compare and assign new objects to a set of pre-defined variability
training classes. For every variability class, a literature search was
performed to find as many well-known member stars as possible, or a
considerable subset if too many were present. Next, we searched on-line and
private databases for their light curves in the visible band and performed
period analysis and harmonic fitting. The derived light curve parameters are
used to describe the classes and define the training classifiers. We compared
the performance of different classifiers in terms of percentage of correct
identification, of confusion among classes and of computation time. We describe
how well the classes can be separated using the proposed set of parameters and
how future improvements can be made, based on new large databases such as the
light curves to be assembled by the CoRoT and Kepler space missions.Comment: This paper has been accepted for publication in Astronomy and
Astrophysics (reference AA/2007/7638) Number of pages: 27 Number of figures:
1
Analysis of MERCATOR data Part I: variable B stars
We re-classified 31 variable B stars which were observed more than 50 times
in the Geneva photometric system with the P7 photometer attached to the
MERCATOR telescope (La Palma) during its first 3 years of scientific
observations. HD89688 is a possible beta Cephei/slowly pulsating B star hybrid
and the main mode of the COROT target HD180642 shows non-linear effects. The
Maia candidates are re-classified as either ellipsoidal variables or spotted
stars. Although the mode identification is still ongoing, all the
well-identified modes so far have a degree l = 0, 1 or 2.Comment: 4 pages, 3 figures. To appear in: Proceedings of JENAM 2005 'Distant
worlds', Communications in Asteroseismolog
Graphs related to Held's simple group
AbstractWe analyze the permutation representations of low degree of Held's simple group He. We also determine its primitive multiplicity free permutation representations and show that there is no graph on which it or its automorphism group acts as a distance transitive group of automorphisms. In doing so, we supply a computer-free construction of He
Vector boson pair production in e-e- collisions with polarized beams
The -boson pair production in collisions with polarized beams is
investigated. The helicity amplitudes are derived for general couplings and the
conditions for a good high-energy behaviour of the cross-section are given. The
results are applied to the heavy vector boson production in the context of the
left-right symmetric model. The Ward identities and the equivalence theorem are
also discussed.Comment: 17 pages+ 8 figures(uuencoded compressed ps-file appended), HU-SEFT R
1994-09 (the original version of the file was unreproducable in some
computers
Charginos and Neutralinos Production at 3-3-1 Supersymmetric Model in Scattering
The goal of this article is to derive the Feynman rules involving charginos,
neutralinos, double charged gauge bosons and sleptons in a 3-3-1 supersymmetric
model. Using these Feynman rules we will calculate the production of a double
charged chargino with a neutralino and also the production of a pair of single
charged charginos, both in an electron- electron process.Comment: 18 pages, 8 figures, 2 table
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