The IR dynamics of effective holographic theories capturing the interplay between charge density and the leading relevant scalar operator at strong coupling are analyzed. Such theories are parameterized by two real exponents (γ, δ) that control the IR dynamics. By studying the thermodynamics, spectra and conductivities of several classes of charged dilatonic black hole solutions that include the charge density back reaction fully, the landscape of such theories in view of condensed matter applications is characterized. Several regions of the (γ, δ) plane can be excluded as the extremal solutions have unacceptable singularities. The classical solutions have generically zero entropy at zero temperature, except when γ = δ where the entropy at extremality is finite. The general scaling of DC resistivity with temperature at low temperature, and AC conductivity at low frequency and temperature across the whole (γ, δ) plane, is found. There is a codimension-one region where the DC resistivity is linear in the temperature. For massive carriers, it is shown that when the scalar operator is not the dilaton, the DC resistivity scales as the heat capacity (and entropy) for planar (3d) systems. Regions are identified where the theory at finite density is a Mott-like insulator at T=0. We also find that at low enough temperatures the entropy due to the charge carriers is generically larger than at zero charge density.

Initial defect size is an important and easily obtainable prognostic factor in osteochondral lesions of the talus and so may serve as a basis for preoperative surgical decisions. A cutoff point exists regarding the risk of clinical failure at a defect area of approximately 150 mm(2) as calculated from magnetic resonance imaging.

Our study describes the clinical outcome of total ankle replacement (TAR) performed in patients with moderate to severe varus deformity. Between September 2004 and September 2007, 23 ankles with a varus deformity > or = 10 degrees and 22 with neutral alignment received a TAR. Following specific algorithms according to joint congruency, the varus ankles were managed by various additional procedures simultaneously with TAR. After a mean follow-up of 27 months (12 to 47), the varus ankles improved significantly in all clinical measures (p < 0.0001 for visual analogue scale and American Orthopaedic Foot and Ankle Society score, p = 0.001 for range of movement). No significant differences were found between the varus and neutral groups regarding the clinical (p = 0.766 for visual analogue scale, p = 0.502 for American Orthopaedic Foot and Ankle Society score, p = 0.773 for range of movement) and radiological outcome (p = 0.339 for heterotopic ossification, p = 0.544 for medial cortical reaction, p = 0.128 for posterior focal osteolysis). Failure of the TAR with conversion to an arthrodesis occurred in one case in each group. The clinical outcome of TAR performed in ankles with pre-operative varus alignment > or = 10 degrees is comparable with that of neutrally aligned ankles when appropriate additional procedures to correct the deformity are carried out simultaneously with TAR.

We construct the hydrodynamics of quantum critical points with Lifshitz scaling. There are new dissipative effects allowed by the lack of boost invariance. The formulation is applicable, in general, to any fluid with an explicit breaking of boost symmetry. We use a Drude model of a strange metal to study the physical effects of the new transport coefficient. It can be measured using electric fields with non-zero gradients, or via the heat production when an external force is turned on. Scaling arguments fix the resistivity to be linear in the temperature.

We report the clinical and radiological outcome of total ankle replacement performed in conjunction with hindfoot fusion or in isolation. Between May 2003 and June 2008, 60 ankles were treated with total ankle replacement with either subtalar or triple fusion, and the results were compared with a control group of 288 ankles treated with total ankle replacement alone. After the mean follow-up of 39.5 months (12 to 73), the ankles with hindfoot fusion showed significant improvement in the mean visual analogue score for pain (p < 0.001), the mean American Orthopaedic Foot and Ankle Society score (p < 0.001), and the mean of a modified version of this score (p < 0.001). The mean visual analogue pain score (p = 0.304) and mean modified American Orthopaedic Foot and Ankle Society score (p = 0.119) were not significantly different between the hindfoot fusion and the control groups. However, the hindfoot fusion group had a significantly lower mean range of movement (p = 0.009) and a higher rate of posterior focal osteolysis (p = 0.04). Both groups showed various complications (p = 0.131) and failure occurring at a similar rate (p = 0.685). Subtalar or triple fusion is feasible and has minimal adverse effects on ankles treated with total ankle replacement up to midterm follow-up. The clinical outcome of total ankle replacement when combined with hindfoot fusion is comparable to that of ankle replacement alone. Thus, hindfoot fusion should be performed in conjunction with total ankle replacement when indicated.

No abstract

We study the properties of the Schrödinger-type non-relativistic holography for general dynamical exponent z with and without hyperscaling violation exponent θ. The scalar correlation function has a more general form due to general z as well as the presence of θ, whose effects also modify the scaling dimension of the scalar operator. We propose a prescription for minimal surfaces of this "codimension 2 holography," and demonstrate the (d − 1) dimensional area law for the entanglement entropy from (d + 3) dimensional Schrödinger backgrounds. Surprisingly, the area law is violated for d + 1 < z < d + 2, even without hyperscaling violation, which interpolates between the logarithmic violation and extensive volume dependence of entanglement entropy. Similar violations are also found in the presence of the hyperscaling violation. Their dual field theories are expected to have novel phases for the parameter range, including Fermi surface. We also analyze string theory embeddings using non-relativistic branes.arXiv:1202.6062v3 [hep-th]

A holographic model of a quantum critical theory at a finite but low temperature and a finite density is studied. The model exhibits non-relativistic z = 2 Schrödinger symmetry and is realized by the antide-Sitter-Schwarzschild black hole in light-cone coordinates. Our approach addresses the electrical conductivities in the presence or absence of an applied magnetic field and contains a control parameter that can be associated with quantum tuning via charge carrier doping or an external field in correlated electron systems. The Ohmic resistivity, the inverse Hall angle, the Hall coefficient and magnetoresistance are shown to be in good agreement with experimental results of strange metals at very low temperature. The holographic model also predicts new scaling relations in the presence of a magnetic field. 7 This unexpected (see, however, [49]) fact can be intuitively understood in analogy with simpler adjoint theories in 0 or 1 dimensions. There it turns out that the eigenvalues of the adjoint matrix in the relevant saddle point become continuous in the large N c limit, and appear as an extra dimension. In general, how many new dimensions may emerge in a given QFT in the large N c limit is not a straightforward question to answer, although exceptions exist. 8 There are several works that contain a version or elements of the idea of the EHT [50], although they vary in the focus or philosophy. 9 We refer to as the 'bulk' the spacetime in which strings propagate. This is always a spacetime with a single boundary. The boundary is isomorphic to the space on which the dual QFT (the gauge theory) lives.