439 research outputs found
Sufficient second-order optimality conditions for semilinear control problems with pointwise state constraints
Second-order sufficient optimality conditions are established for the optimal control of semilinear elliptic and parabolic equations with pointwise constraints on the control and the state. In contrast to former publications on this subject, the cone of critical directions is the smallest possible in the sense that the second-order sufficient conditions are the closest to the associated necessary ones. The theory is developed for elliptic distributed controls in domains up to dimension three. Moreover, problems of elliptic boundary control and parabolic distributed control are discussed in spatial domains of dimension two and one, respectively
On non-perturbative corrections to the Kahler potential
We present the results of a detailed investigation into the consequences of
adding specific string motivated non-perturbative corrections to the usual tree
level Kahler potential in dilaton dominated scenarios. The success of the model
is judged through our ability to obtain a realistic VEV for the dilaton < Re S
> ~ 2, corresponding to the true minima of the scalar potential and being
associated with a reasonable value for the SUSY breaking scale via the
gravitino mass. The status of the so-called moduli problem is also reviewed in
each of the ansatze studied. Those include previous proposals made in the
context of both the chiral and the linear multiplet formalisms to describe
gaugino condensation, and a new ansatz which shows explicitly the equivalence
between the two.Comment: 11 pages, LaTex, uses psfig.sty with 4 figure
El análisis foliar para la fertilización del algodonero: principios generales y sistemas de muestreo.
The problem, and B and L Conservation with a Discrete Gauge R Symmetry
We examine in a generic context how the problem can be resolved by
means of a spontaneously broken gauge symmetry. We then focus on the new scheme
based on a discrete gauge R symmetry which is spontaneously broken by
nonperturbative hidden sector dynamics triggering supersymmetry breaking also.
The possibility to suppress the dangerous baryon and/or lepton number violating
interactions by means of this discrete R symmetry is examined also together
with some phenomenological consequences.Comment: 13 pages, RevTex, no figure
Model Independent Properties and Cosmological Implications of the Dilaton and Moduli Sectors of 4-d Strings
We show that if there is a realistic 4-d string, the dilaton and moduli
supermultiplets will generically acquire a small mass O(m_{3/2}), providing the
only vacuum-independent evidence of low-energy physics in string theory beyond
the supersymmetric standard model. The only assumptions behind this result are
(i) softly broken supersymmetry at low energies with zero cosmological
constant, (ii) these particles interact with gravitational strength and the
scalar components have a flat potential in perturbation theory, which are
well-known properties of string theories. (iii) They acquire a of the
order of the Planck scale (as required for the correct value of the gauge
coupling constants and the expected compactification scale) after supersymmetry
gets broken. We explore the cosmological implications of these particles.
Similar to the gravitino, the fermionic states may overclose the Universe if
they are stable or destroy nucleosynthesis if they decay unless their masses
belong to a certain range or inflation dilutes them. For the scalar states it
is known that the problem cannot be entirely solved by inflation, since
oscillations around the minimum of the potential can lead to a huge entropy
generation at late times. We discus some possible ways to alleviate this
entropy problem, that favour low-temperature baryogenesis, and also comment on
the possible role of these particles as dark matter candidates or as sources of
the baryon asymmetry through their decay.Comment: 15 pages,CERN-TH.6958/93,NEIP-93-006, IEM-FT-75/93, Late
Non-Universal Gaugino Masses and the Fate of mu -> e gamma
We study charged lepton flavor violating processes in the context of
supersymmetric models with non-universal gaugino masses. We consider the
generic case of free gaugino masses, as well as specific models based on
gaugino mediation and SU(5) GUTs. Under the assumption that the main source of
lepton flavor violation resides in the off-diagonal elements of the left handed
slepton mass matrix, we show that BR(mu->e gamma) strongly depends on gaugino
non-universality. When M_1 and M_2 have opposite signs, cancellations occurring
between the neutralino and the chargino contributions can suppress, even
completely, the branching ratio of charged lepton flavor violating decays.
Moreover, we find that for M_3> M_2,M_1, BR(mu->e gamma) is an increasing
function of M_3.Comment: 14 pages, 10 figures; Accepted for publication in Nuclear Physics
Flavor changing neutral current constraints on standard-like orbifold models
We examine for standard-like orbifold compactification models the constraints
due to quarks and leptons generation non-universality of soft supersymmetry
breaking interactions. We follow the approach initiated by Ibanez and Lust and
developed by Brignole, Ibanez and Munoz. The breaking of supersymmetry is
represented in terms of dilaton and moduli auxiliary field components and,
consistently with a vanishing cosmological constant, is parametrized in terms
of the dilaton-moduli mixing angle and the gravitino mass scale
. The soft breaking interactions (gaugino masses, squarks and sleptons
mass matrices, scalars interactions A and B coupling constants) are calculable
as a function of these parameters and of the discrete set of modular weight
parameters specifying the modular transformation properties of the low-energy
fields. We solve the renormalization group one-loop equations for the full set
of gauge, Yukawa and supersymmetry breaking coupling constants.Comment: 32 page
Stabilizing dilaton and baryogenesis
Entropy production by the dilaton decay is studied in the model where the
dilaton acquires potential via gaugino condensation in the hidden gauge group.
Its effect on the Affleck-Dine baryogenesis is investigated with and without
non-renormalizable terms in the potential. It is shown that the baryon
asymmetry produced by this mechanism with the higher-dimensional terms is
diluted by the dilaton decay and can be regulated to the observed value.Comment: 20 pages, 3 figures, baryon asymmetry revised, errors corrected,
references and comments adde
El aeropuerto, una interfaz conectiva en el territorio
El presente trabajo tiene por objeto señalar algunos aspectos de conflictividad de las instalaciones aeroportuarias de nuestro medio en relación con su presencia en el territorio y con su vinculación con las estructuras urbanas.
Uno de los temas principales de esta conflictividad es la escasa conectividad que presentan los aeropuertos provocados por falta de planificación integral, inversiones y actualización de criterios infraestructurales.
Por otro lado, las relaciones físicas entre el aeropuerto y su predio y la estructura urbana vecina, denotan otras áreas de conflicto que reclaman una visión sistémica en el campo de la planificación territorial.Grupo de Transporte Aéreo - Grupo de Ingeniería Aplicada a la Industri
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