290 research outputs found
Product costing and activity-based costing/management in Bacalhôa Vinhos de Portugal
The present Work Project introduces a case study addressing the adoption of an ABC/M system in a winemaking company. The system was implemented in only one area of the company, and its adoption allows the company to perform ABM analysis resorting to the ABC information. A mixed approach is used to cost the products: both traditional and ABC systems are used although in different areas of the company. ABC/M implementation was perceived as ‘successful’ despite not following recommendations prescribed in literature
Symmetries of Large N Matrix Models for Closed Strings
We obtain the symmetry algebra of multi-matrix models in the planar large N
limit. We use this algebra to associate these matrix models with quantum spin
chains. In particular, certain multi-matrix models are exactly solved by using
known results of solvable spin chain systems.Comment: 12 pages, 1 eps figure, RevTex, some minor typos in the publised
version are correcte
Constructing Infinite Particle Spectra
We propose a general construction principle which allows to include an
infinite number of resonance states into a scattering matrix of hyperbolic
type. As a concrete realization of this mechanism we provide new S-matrices
generalizing a class of hyperbolic ones, which are related to a pair of simple
Lie algebras, to the elliptic case. For specific choices of the algebras we
propose elliptic generalizations of affine Toda field theories and the
homogeneous sine-Gordon models. For the generalization of the sinh-Gordon model
we compute explicitly renormalization group scaling functions by means of the
c-theorem and the thermodynamic Bethe ansatz. In particular we identify the
Virasoro central charges of the corresponding ultraviolet conformal field
theories.Comment: 7 pages Latex, 7 figures (typo in figure 3 corrected
A Comment on Masses, Quantum Affine Symmetries and PP-Wave Backgrounds
Two dimensional light cone world sheet massive models can be used to define
good string backgrounds.In many cases these light cone world sheet lagrangians
flow from a CFT in the UV to a theory of massive particles in the IR. The
relevant symmetry in the IR, playing a similar role to Virasoro in the UV, are
quantum affine Kac Moody algebras. Finite dimensional irreps of this algebra
are associated with the spectrum of massive particles. The case of N=0 Sine
Gordon at the N=2 point is associated with a Landau Ginzburg model that defines
a good string background. For the world sheet symmetry the N=2 piece is associated with the string conformal
invariance and the piece with the world sheet RG. The two
dimensional light cone world sheet massive model can be promoted to a CFT by
adding extra light cone fields and . From the point of view of
the quantum affine symmetry these two fields are associated, respectively, with
the center and the derivation of the affine Kac Moody algebra.Comment: 9 pages. Typos correcte
Quantum matrix algebra for the SU(n) WZNW model
The zero modes of the chiral SU(n) WZNW model give rise to an intertwining
quantum matrix algebra A generated by an n x n matrix a=(a^i_\alpha) (with
noncommuting entries) and by rational functions of n commuting elements
q^{p_i}. We study a generalization of the Fock space (F) representation of A
for generic q (q not a root of unity) and demonstrate that it gives rise to a
model of the quantum universal enveloping algebra U_q(sl_n), each irreducible
representation entering F with multiplicity 1. For an integer level k the
complex parameter q is an even root of unity, q^h=-1 (h=k+n) and the algebra A
has an ideal I_h such that the factor algebra A_h = A/I_h is finite
dimensional.Comment: 48 pages, LaTeX, uses amsfonts; final version to appear in J. Phys.
Axion Searches with Helioscopes and astrophysical signatures for axion(-like) particles
The first part reviews the working mechanisms, capabilities and performance
of axion helioscopes, including the achieved results so far. The 2nd part is
observationally driven. New simulation results obtained with the Geant4 code
reconstruct spectral shape of solar X-ray spectra, and their isotropic emission
and lateral size. The derived rst mass of the axion(-like) particles is ~10meV.
The axion interaction with magnetic field gradient is a generic theoretical
suggestion that could reconcile present limits with relevant solar X-ray
activity. A short outlook of the experimentally expanding solar axion field is
given.Comment: 31 pages, 18 figures. Aded 1 author, updated references. Accepted for
the special issue of NJP on dark matter (July 2009
The effect of dietary antioxidant supplementation in a vertebrate host on the infection dynamics and transmission of avian malaria to the vector.
Host susceptibility to parasites is likely to be influenced by intrinsic factors, such as host oxidative status determined by the balance between pro-oxidant production and antioxidant defences. As a result, host oxidative status acts as an environmental factor for parasites and may constrain parasite development. We evaluated the role of host oxidative status on infection dynamics of an avian malarial parasite by providing canaries (Serinus canaria) with an antioxidant supplementation composed of vitamin E (a lipophilic antioxidant) and olive oil, a source of monounsaturated fatty acids. Another group received a standard, non-supplemented food. Half of the birds in each group where then infected with the haemosporidian parasite, Plasmodium relictum. We monitored the parasitaemia, haematocrit level, and red cell membrane resistance, as well as the transmission success of the parasite to its mosquito vector, Culex pipiens. During the acute phase, the negative effect of the infection was more severe in the supplemented group, as shown by a lower haematocrit level. Parasitaemia was lower in the supplemented group during the chronic phase only. Mosquitoes fed on supplemented hosts were more often infected than mosquitoes fed on the control group. These results suggest that dietary antioxidant supplementation conferred protection against Plasmodium in the long term, at the expense of a short-term negative effect. Malaria parasites may take advantage of antioxidants, as shown by the increased transmission rate in the supplemented group. Overall, our results suggest an important role of oxidative status in infection outcome and parasite transmission
A short review on entanglement in quantum spin systems
We review some of the recent progress on the study of entropy of entanglement
in many-body quantum systems. Emphasis is placed on the scaling properties of
entropy for one-dimensional multi-partite models at quantum phase transitions
and, more generally, on the concept of area law. We also briefly describe the
relation between entanglement and the presence of impurities, the idea of
particle entanglement, the evolution of entanglement along renormalization
group trajectories, the dynamical evolution of entanglement and the fate of
entanglement along a quantum computation.Comment: 20 pages and 6 figures. Review article for the special issue
"Entanglement entropy in extended systems" in J. Phys. A, edited by P.
Calabrese, J. Cardy and B. Doyo
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