9,963 research outputs found
Evolution of squeezed states under the Fock-Darwin Hamiltonian
We develop a complete analytical description of the time evolution of
squeezed states of a charged particle under the Fock-Darwin Hamiltonian and a
time-dependent electric field. This result generalises a relation obtained by
Infeld and Pleba\'nski for states of the one-dimensional harmonic oscillator.
We relate the evolution of a state-vector subjected to squeezing to that of
state which is not subjected to squeezing and for which the time-evolution
under the simple harmonic oscillator dynamics is known (e.g. an eigenstate of
the Hamiltonian). A corresponding relation is also established for the Wigner
functions of the states, in view of their utility in the analysis of cold-ion
experiments. In an appendix, we compute the response functions of the FD
Hamiltonian to an external electric field, using the same techniques as in the
main text
Off-shell N=2 tensor supermultiplets
A multiplet calculus is presented for an arbitrary number n of N=2 tensor
supermultiplets. For rigid supersymmetry the known couplings are reproduced. In
the superconformal case the target spaces parametrized by the scalar fields are
cones over (3n-1)-dimensional spaces encoded in homogeneous SU(2) invariant
potentials, subject to certain constraints. The coupling to conformal
supergravity enables the derivation of a large class of supergravity
Lagrangians with vector and tensor multiplets and hypermultiplets. Dualizing
the tensor fields into scalars leads to hypermultiplets with hyperkahler or
quaternion-Kahler target spaces with at least n abelian isometries. It is
demonstrated how to use the calculus for the construction of Lagrangians
containing higher-derivative couplings of tensor multiplets. For the
application of the c-map between vector and tensor supermultiplets to
Lagrangians with higher-order derivatives, an off-shell version of this map is
proposed. Various other implications of the results are discussed. As an
example an elegant derivation of the classification of 4-dimensional
quaternion-Kahler manifolds with two commuting isometries is given.Comment: 36 page
Biocorrosion and biofilm formation in a nutrient limited heating system subjected to alternating microaerophilic conditions
Severe biofilm formation and biocorrosion have been observed in heating systems even when the water quality complied with existing standards. The coupling between water chemistry, biofilm formation, species composition, and biocorrosion in a heating system was investigated by adding low concentrations of nutrients and oxygen under continuous and alternating dosing regimes. Molecular analysis of 16S rRNA gene fragments demonstrated that the amendments did not cause changes in the overall bacterial community composition. The combined alternating dosing of nutrients and oxygen caused increased rates of pitting (bio-) corrosion. Detection of bacteria involved in sulfide production and oxidation by retrieval of the functional dsrAB and apsA genes revealed the presence of Gram-positive sulfate- and sulfite-reducers and an unknown sulfur-oxidizer. Therefore, to control biocorrosion, sources of oxygen and nutrients must be limited, since the effect of the alternating operational conditions apparently is more important than the presence of potentially corrosive biofilm bacteria
A protocol for large scale genomic DNA isolation for cacao genetics analysis
Advances in DNA technology, such as marker assisted selection, detection of quantitative trait loci and genomic selection also require the isolation of DNA from a large number of samples and the preservation of tissue samples for future use in cacao genome studies. The present study proposes a method for the preservation of sample tissues for DNA extraction and for manual extraction of large number of samples using spheres. The integrity and concentration of the DNA by these methods were assessed and compared with conventional method using mortar. The best parameters in order to obtain a fine powder using spheres was the use of 4 lyophilized leaf disks (50 mg), a single steel ball of 6 mm in diameter, followed by 30 s of manual maceration. The quantity of DNA obtained was four times higher than the conventional method. The purity of the DNA obtained was satisfactory and proved to be amplifiable by PCR using SSR primers. The present approach is a reliable, rapid, simple and consistent DNA isolation method for cacao, compared to the conventional methods. The protocol greatly increases the efficiency of extraction and suggests an inexpensive and practical way of DNA isolation of cacao for large scale.Keywords: DNA extraction, cacao, spheres, lyophilized
Special Geometry of Euclidean Supersymmetry III: the local r-map, instantons and black holes
We define and study projective special para-Kahler manifolds and show that
they appear as target manifolds when reducing five-dimensional vector
multiplets coupled to supergravity with respect to time. The dimensional
reductions with respect to time and space are carried out in a uniform way
using an epsilon-complex notation. We explain the relation of our formalism to
other formalisms of special geometry used in the literature. In the second part
of the paper we investigate instanton solutions and their dimensional lifting
to black holes. We show that the instanton action, which can be defined after
dualising axions into tensor fields, agrees with the ADM mass of the
corresponding black hole. The relation between actions via Wick rotation, Hodge
dualisation and analytic continuation of axions is discussed.Comment: 72 pages, 2 figure
Estimativas de parâmetros genéticos de características de carcaça e maciez da carne em bovinos da raça Nelore mocho.
Objetivou-se com este estudo estimar as herdabilidades e correlações genéticas entre a característica de maciez da carne (WBSF - Warner-Bratzler shear force) e as características de carcaça EG, P8 E AOL (espessura de gordura na costela, espessura de gordura na garupa e área de olho de lombo, respectivamente) de 415 animais com idade variando de 24 a 26 meses, filhos de 22 touros acasalados com 552 vacas, provenientes do Programa OB Choice da Marca OB.Pôster - pós-graduação
G-structures and Domain Walls in Heterotic Theories
We consider heterotic string solutions based on a warped product of a
four-dimensional domain wall and a six-dimensional internal manifold,
preserving two supercharges. The constraints on the internal manifolds with
SU(3) structure are derived. They are found to be generalized half-flat
manifolds with a particular pattern of torsion classes and they include
half-flat manifolds and Strominger's complex non-Kahler manifolds as special
cases. We also verify that previous heterotic compactifications on half-flat
mirror manifolds are based on this class of solutions.Comment: 29 pages, reference added, typos correcte
Functional analysis of rice phosphorus-starvation tolerance 1 gene and its sorghum and maize homologs in transgenic tobacco.
Comparison of the properties of two fossil groups of galaxies with the normal group NGC 6034 based on multiband imaging and optical spectroscopy
We collected multiband imaging and spectroscopy for two fossil groups (RX
J1119.7+2126 and 1RXS J235814.4+150524) and one normal group (NGC 6034). We
computed photometric redshifts in the central zones of each group, combining
previous data with the SDSS five-band data. For each group we investigated the
red sequence (RS) of the color-magnitude relation and computed the luminosity
functions, stellar population ages and distributions of the group members.
Spectroscopy allowed us to investigate the large-scale surroundings of these
groups and the substructure levels in 1RXS J235814.4+150524 and NGC 6034. The
large-scale environment of 1RXS J235814.4+150524 is poor, though its galaxy
density map shows a clear signature of the surrounding cosmic web. RX
J1119.7+2126 appears to be very isolated, while the cosmic environment of NGC
6034 is very rich. At the group scale, 1RXS J235814.4+150524 shows no
substructure. Galaxies with recent stellar populations seem preferentially
located in the group outskirts. A RS is discernable for all three groups in a
color-magnitude diagram. The luminosity functions based on photometric redshift
selection and on statistical background subtraction have comparable shapes, and
agree with the few points obtained from spectroscopic redshifts. These
luminosity functions show the expected dip between first and second brightest
galaxies for the fossil groups only. Their shape is also regular and relatively
flat at faint magnitudes down to the completeness level for RX J1119.7+2126 and
NGC 6034, while there is a clear lack of faint galaxies for 1RXS
J235814.4+150524. RX J1119.7+2126 is definitely classified as a fossil group;
1RXS J235814.4+150524 also has properties very close to those of a fossil
group, while we confirm that NGC 6034 is a normal group.Comment: Accepted in A&A, english-improved, 5 jpeg figures, and shortened
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