2,680 research outputs found
Confinement and Condensates Without Fine Tuning in Supergravity Duals of Gauge Theories
We discuss a solution of the equations of motion of five-dimensional gauged
type IIB supergravity that describes confining SU(N) gauge theories at large N
and large 't Hooft parameter. We prove confinement by computing the Wilson
loop, and we show that our solution is generic, independent of most of the
details of the theory. In particular, the Einstein-frame metric near its
singularity, and the condensates of scalar, composite operators are universal.
Also universal is the discreteness of the glueball mass spectrum and the
existence of a mass gap. The metric is also identical to a generically
confining solution recently found in type 0B theory.Comment: 19 pages, Late
Novel Local CFT and Exact Results on Perturbations of N=4 Super Yang Mills from AdS Dynamics
We find new, local, non-supersymmetric conformal field theories obtained by
relevant deformations of the N=4 super Yang Mills theory in the large
limit. We contruct interpolating supergravity solutions that naturally
represent the flow from the N=4 super Yang Mills UV theory to these
non-supersymmetric IR fixed points. We also study the linearization around the
N=4 superconformal point of N=1 supersymmetric, marginal deformations. We show
that they give rise to N=1 superconformal fixed points, as expected from
field-theoretical arguments.Comment: Version accepted by JHE
Nebivolol: haemodynamic effects and clinical significance of combined beta-blockade and nitric oxide release.
Nebivolol is a third-generation beta-adrenergic receptor antagonist (beta-blocker) with high selectivity for beta(1)-adrenergic receptors. In addition, it causes vasodilatation via interaction with the endothelial L-arginine/nitric oxide (NO) pathway. This dual mechanism of action underlies many of the haemodynamic properties of nebivolol, which include reductions in heart rate and blood pressure (BP), and improvements in systolic and diastolic function. With respect to BP lowering, the NO-mediated effects cause a reduction in peripheral vascular resistance and an increase in stroke volume with preservation of cardiac output. Flow-mediated dilatation and coronary flow reserve are also increased during nebivolol administration. Other haemodynamic effects include beneficial effects on pulmonary artery pressure, pulmonary wedge pressure, exercise capacity and left ventricular ejection fraction. In addition, nebivolol does not appear to have adverse effects on lipid metabolism and insulin sensitivity like traditional beta-blockers. The documented beneficial haemodynamic effects of nebivolol are translated into improved clinical outcomes in patients with hypertension or heart failure. In patients with hypertension, the incidence of bradycardia with nebivolol is often lower than that with other currently available beta-blockers. This, along with peripheral vasodilatation and NO-induced benefits such as antioxidant activity and reversal of endothelial dysfunction, should facilitate better protection from cardiovascular events. In addition, nebivolol has shown an improved tolerability profile, particularly with respect to events commonly associated with beta-blockers, such as fatigue and sexual dysfunction. Data from SENIORS (Study of the Effects of Nebivolol Intervention on Outcomes and Rehospitalization in Seniors with Heart Failure) showed that significantly fewer nebivolol versus placebo recipients experienced the primary endpoint of all-cause mortality or cardiovascular hospitalization. The benefits of nebivolol therapy were shown to be cost effective. Thus, nebivolol is an effective and well tolerated agent with benefits over and above those of traditional beta-blockade because of its effects on NO release, which give it unique haemodynamic effects, cardioprotective activity and a good tolerability profile
A água: distribuição, regulamentação e uso na agricultura, com enfase ao arroz irrigado.
bitstream/item/45267/1/documento-250.pd
Supersymmetric AdS vacua and separation of scales
The moduli space of the supersymmetric massive IIA AdS4xS2(B4) vacua, where
S2(B4) is a two-sphere bundle over a four-dimensional Kaehler-Einstein base B4,
includes three independent parameters which can be thought of as corresponding
to the sizes of AdS4, B4 and the S2 fiber. It might therefore be expected that
these vacua do not suffer from the absence of scale separation. We show that
the independence of the geometric moduli survives flux quantization. However,
we uncover an attractor behavior whereby all sizes flow to equality in some
neighborhood of spacetime independently of the initial conditions set by the
parameters of the solution. This is further confirmed by the study of the ratio
of internal to external scalar curvatures. We also show that the asymptotic
Kaluza-Klein spectrum of a ten-dimensional massive scalar is governed by a
scale of the order of the AdS4 radius. Furthermore we point out that the
curvature ratio in supersymmetric IIA AdS4 vacua with rigid SU(3) structure is
of order one, indicating the absence of scale separation in this large class of
vacua.Comment: 21 pages, 2 figures; v2 typos correcte
Biodegradable magnesium coronary stents: Material, design and fabrication
Biodegradable cardiovascular stents in magnesium (Mg) alloys constitute a promising option for a less intrusive treatment, due to their high compatibility with the body tissue and intrinsic dissolution in body fluids. The design and fabrication aspects of this medical device require an integrated approach considering different aspects such as mechanical properties, corrosion behaviour and biocompatibility. This work gathers and summarises a multidisciplinary work carried out by three different research teams for the design and fabrication of Mg stents. In particular, the paper discusses the design of the novel stent mesh, the deformability study of the Mg alloys for tubular raw material and laser microcutting for the realisation of the stent mesh. Although, the results are not fully validated as the device has not been fully tested, they show the feasibility of the used approaches, as the first prototype stents in Mg alloy were produced successfully. © 2013 Copyright Taylor and Francis Group, LLC
Gravity duals to deformed SYM theories and Generalized Complex Geometry
We analyze the supersymmetry conditions for a class of SU(2) structure
backgrounds of Type IIB supergravity, corresponding to a specific ansatz for
the supersymmetry parameters. These backgrounds are relevant for the AdS/CFT
correspondence since they are suitable to describe mass deformations or
beta-deformations of four-dimensional superconformal gauge theories. Using
Generalized Complex Geometry we show that these geometries are characterized by
a closed nowhere-vanishing vector field and a modified fundamental form which
is also closed. The vector field encodes the information about the
superpotential and the type of deformation - mass or beta respectively. We also
show that the Pilch-Warner solution dual to a mass-deformation of N =4 Super
Yang-Mills and the Lunin-Maldacena beta-deformation of the same background fall
in our class of solutions.Comment: LaTex, 29 page
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