10,069 research outputs found
Pinguicula rosmarieae Casper, Bussmann & T.Henning (Lentibulariaceae), a new butterwort from the Amotape-Huancabamba Zone (northern Peru)
The insectivorous genus Pinguicula occurs along the whole Andean mountain chain from Colombia-Venezuela in the north to Tierra del Fuego in the south with a short interruption in the Peruvian-Chilean desert range. This paper describes a new and striking species of Pinguicula that occurs in the south-eastern part of the Amotape-Huancabamba Zone in north Peru. It grows either as a lithophyte on moist rocks or as an epiphyte on Polylepis multijuga Pilg. in the wet highlands of the Cordillera Central. Pinguicula rosmarieae Casper, Bussmann & T.Henning, sp. nov. is clearly distinguished by a basal rosette of ovate-obovate leaves spread out flat on the ground and especially by a two-partite corolla with a straight uniform tube-spur complex, two features unknown from other Andean Pinguicula species. The morphological similarity to P. calyptrata Kunth is discussed and the habitat and distribution of P. rosmarieae are characterised
Analytical results for O(\alpha_s) radiative corrections to e+ e- -> tbar t(pol.) up to a given gluon energy cut
We determine the O(\alpha_s) radiative corrections to polarized top quark
pair production in e+ e- -annihilations with a specified gluon energy cut. We
write down fully analytical results for the unpolarized and polarized
O(\alpha_s) cross sections e+ e- -> tbar t (G) and e+ e- -> tbar t(pol.) (G)
including their polar orientation dependence relative to the beam direction. In
the soft gluon limit we recover the usual factorizing form known from the soft
gluon approximation. In the limit when the gluon energy cut takes its maximum
value we recover the totally inclusive unpolarized and polarized cross sections
calculated previously. We provide some numerical results on the cut-off
dependence of the various polarized and unpolarized cross sections and discuss
how the exact results numerically differ from the approximate soft-gluon
results.Comment: 49 pages in LaTeX, including 17 encapsulated PostScript figure
Hodge numbers for the cohomology of Calabi-Yau type local systems
We use Higgs cohomology to determine the Hodge numbers of the first
intersection cohomology group of a local system V arising from the third direct
image of a family of Calabi-Yau 3-folds over a smooth, quasi-projective curve.
We give applications to Rhode's families of Calabi-Yau 3-folds without MUM.Comment: Some signs corrected. This article draws heavily from arXiv:0911.027
Extrapolation of K to \pi\pi decay amplitude
We examine the uncertainties involved in the off-mass-shell extrapolation of
the decay amplitude with emphasis on those aspects that
have so far been overlooked or ignored. Among them are initial-state
interactions, choice of the extrapolated kaon field, and the relation between
the asymptotic behavior and the zeros of the decay amplitude. In the inelastic
region the phase of the decay amplitude cannot be determined by strong
interaction alone and even its asymptotic value cannot be deduced from
experiment. More a fundamental issue is intrinsic nonuniqueness of off-shell
values of hadronic matrix elements in general. Though we are hampered with
complexity of intermediate-energy meson interactions, we attempt to obtain a
quantitative idea of the uncertainties due to the inelastic region and find
that they can be much larger than more optimistic views portray.Comment: 16 pages with 5 eps figures in REVTE
Transport and thermoelectric properties of the LaAlO/SrTiO interface
The transport and thermoelectric properties of the interface between
SrTiO and a 26-monolayer thick LaAlO-layer grown at high
oxygen-pressure have been investigated at temperatures from 4.2 K to 100 K and
in magnetic fields up to 18 T. For 4.2 K, two different electron-like
charge carriers originating from two electron channels which contribute to
transport are observed. We probe the contributions of a degenerate and a
non-degenerate band to the thermoelectric power and develop a consistent model
to describe the temperature dependence of the thermoelectric tensor. Anomalies
in the data point to an additional magnetic field dependent scattering.Comment: 7 pages, 4 figure
Workshop on Mapping out a CCAFS R4D Agenda and Strategy for Southeast Asia
Taking off from the convergence meeting of CGIAR Centers and selected
partners in December 2013, this regional workshop to mapped out a CCAFS
R4D agenda and strategy for Southeast Asia (SEA). The region was added to
the CCAFS portfolio (East Africa, West Africa, South America, South Asia) in
order to make the program fully global
Representation of Markov chains by random maps: existence and regularity conditions
We systematically investigate the problem of representing Markov chains by
families of random maps, and which regularity of these maps can be achieved
depending on the properties of the probability measures. Our key idea is to use
techniques from optimal transport to select optimal such maps. Optimal
transport theory also tells us how convexity properties of the supports of the
measures translate into regularity properties of the maps via Legendre
transforms. Thus, from this scheme, we cannot only deduce the representation by
measurable random maps, but we can also obtain conditions for the
representation by continuous random maps. Finally, we present conditions for
the representation of Markov chain by random diffeomorphisms.Comment: 22 pages, several changes from the previous version including
extended discussion of many detail
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