2,087 research outputs found
Holographic phase transitions from higgsed, non abelian charged black holes
We find solutions of a gravity-Yang-Mills-Higgs theory in four dimensions
that represent asymptotic anti-de Sitter charged black holes with partial/full
gauge symmetry breaking. We then apply the AdS/CFT correspondence to study the
strong coupling regime of a quantum field theory at temperature and
finite chemical potential, which undergoes transitions to phases exhibiting the
condensation of a composite charged vector operator below a critical
temperature , presumably describing -wave superconductors. In the
case of -wave superconductors the transitions are always of second order.
But for -wave superconductors we determine the existence of a critical value
of the gravitational coupling (for fixed Higgs v.e.v. parameter
) beyond which the transitions become of first order. As a
by-product, we show that the -wave phase is energetically favored over the
one, for any values of the parameters. We also find the ground state
solutions corresponding to zero temperature. Such states are described by
domain wall geometries that interpolate between spaces with different
light velocities, and for a given , they exist below a critical
value of the coupling. The behavior of the order parameter as function of the
gravitational coupling near the critical coupling suggests the presence of
second order quantum phase transitions. We finally study the dependence of the
solution on the Higgs coupling, and find the existence of a critical value
beyond which no condensed solution is present.Comment: 29 pages, 43 figure
Shear banding in nematogenic fluids with oscillating orientational dynamics
We investigate the occurrence of shear banding in nematogenic fluids under
planar Couette flow, based on mesoscopic dynamical equations for the
orientational order parameter and the shear stress. We focus on parameter
values where the sheared homogeneous system exhibits regular oscillatory
orientational dynamics, whereas the equilibrium system is either isotropic
(albeit close to the isotropic--nematic transition) or deep in its nematic
phase. The numerical calculations are restricted to spatial variations in shear
gradient direction. We find several new types of shear banded states
characterized by regions with regular oscillatory orientational dynamics. In
all cases shear banding is accompanied by a non--monotonicity of the flow curve
of the homogeneous system; however, only in the case of the initially isotropic
system this curve has the typical --like shape. We also analyze the
influence of different orientational boundary conditions and of the spatial
correlation length.Comment: 12 pages, 10 figure
COMPETITIVENESS OF SMOOTH PIGWEED, LARGE CRABGRASS AND SNAP BEAN UNDER GREENHOUSE CONDITIONS
COMPETITIVENESS OF SMOOTH PIGWEED, LARGE CRABGRASS AND SNAP BEAN UNDER GREENHOUSE CONDITION
La protección del patrimonio arqueológico en Castilla-La Mancha. Reflexiones sobre la Ley 4/2013 de patrimonio cultural
La nueva Ley 4/2013 ha aportado al panorama arqueológico de Castilla-La Mancha importantes novedades que el autor analiza y comenta desde una óptica personal. La Ley, aprobada la pasada primavera, multiplica los instrumentos jurÃdicos con que se dota a la Administración competente en la conservación del patrimonio cultural. Asimismo, supone el complemento normativo necesario al innovador Código Deontológico de la ArqueologÃa y Patrimonio de Castilla-La Mancha recientemente aprobado en esta región. Este innovador Código aborda aquellos aspectos que, por implicar más a la ética que a la norma, no son definidos por ést
COMBINED EFFECT OF LARGE CRABGRASS AND SMOOTH PIGWEED DENSITIES ON SNAP BEAN YIELD
COMBINED EFFECT OF LARGE CRABGRASS AND SMOOTH PIGWEED DENSITIES ON SNAP BEAN YIEL
Robust Control Algorithm for a Two Cart System and an Inverted Pendulum
The Rectilinear Control System can be used to simulate a launch vehicle during liftoff. Several control schemes have been developed that can control different dynamic models of the rectilinear plant. A robust control algorithm was developed that can control a pendulum to maintain an inverted position. A fluid slosh tank will be attached to the pendulum in order to test robustness in the presence of unknown slosh characteristics. The rectilinear plant consists of a DC motor and three carts mounted in series. Each cart s weight can be adjusted with brass masses and the carts can be coupled with springs. The pendulum is mounted on the first cart and an adjustable air damper can be attached to the third cart if desired. Each cart and the pendulum have a quadrature encoder to determine position. Full state feedback was implemented in order to develop the control algorithm along with a state estimator to determine the velocity states of the system. A MATLAB program was used to convert the state space matrices from continuous time to discrete time. This program also used a desired phase margin and damping ratio to determine the feedback gain matrix that would be used in the LabVIEW program. This experiment will allow engineers to gain a better understanding of liquid propellant slosh dynamics, therefore enabling them to develop more robust control algorithms for launch vehicle system
El furtivismo arqueológico. Consideraciones legales y cientÃficas sobre los hallazgos arqueológicos
El problema de las actuaciones arqueológicas incontroladas realizadas por no profesionales es un fenómeno social que viene desde antiguo. La proliferación de estos ‘’aficionados’’ a la ArqueologÃa que buscan, recogen, se guardan y a menudo venden objetos arqueológicos es uno de los principales obstáculos con el que nos encontramos los arqueólogos a la hora de reconstruir los modos de vida de nuestros antepasado
The prehistoric culture of the Motillas: new approaches to an old problem
Los inicios de la caracterización de la Cultura de las Motillas se sitúan hace
cuatro décadas. Desde entonces diversas universidades y expertos han intentado encontrar
explicación a las causas del origen, evolución y desaparición de este singular grupo humano
que habitó La Mancha durante la Prehistoria Reciente. Los últimos avances en la investigación
permiten plantear tres datos de importancia para el tema. En primer lugar, las motillas
pueden ser en realidad el más antiguo sistema de captación de agua subterránea del accidente
europeo. En segundo lugar, la implantación de esta red de pozos pudo estar relacionada con
una crisis climática que hizo desaparecer de forma generalizada las aguas superficiales durante
un largo periodo de tiempo, debido al Evento Climático 4.2 ka BP. En tercer lugar, las
motillas son tells muy similares en lo formal a los túmulos funerarios. Acaba de ser definido
un horizonte funerario tumular asociado a la Cultura de las Motillas que era desconocido
por completo. Este trabajo aporta, además, el inventario actualizado de todas las motillas conocidasThe investigation of the Culture of the Motillas began four decades ago. Since
then, various scholars have tried to ellucidate the origin, development and disappearance
of this singular human group that existed during the Late Prehistory in La Mancha (South
Central Plateau, Spain). As a result of recent research, three important issues about this
question have arisen. First, the Motillas could possibly be the oldest system of underground
water collection in Westerm Europe in Europe. Second, the implementation of this network
of wells could be related to a climate crisis that could have dried the surface water for a
long period of time, related to the 4.2 ka BP Climate Event. Third, the Motillas are tells,
very similar in form to burial mounds. Funerary tumuli associated with the Culture of the
Motillas have recently been described. This work also provides an updated inventory of all
known Motilla
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