Effective Dynamics of Extended Fermi Gases in the High-Density Regime.

We study the quantum evolution of many-body Fermi gases in three dimensions, in arbitrarily large domains. We consider both particles with non-relativistic and with relativistic dispersion. We focus on the high-density regime, in the semiclassical scaling, and we consider a class of initial data describing zero-temperature states. In the non-relativistic case we prove that, as the density goes to infinity, the many-body evolution of the reduced one-particle density matrix converges to the solution of the time-dependent Hartree equation, for short macroscopic times. In the case of relativistic dispersion, we show convergence of the many-body evolution to the relativistic Hartree equation for all macroscopic times. With respect to previous work, the rate of convergence does not depend on the total number of particles, but only on the density: in particular, our result allows us to study the quantum dynamics of extensive many-body Fermi gases.

Correction of a severe coronal malalignment in adult spinal deformity using the "kickstand rod" technique as primary surgery.

OBJECTIVE: Adult spinal deformity (ASD) is a growing healthcare issue due to the aging population. A satisfying spine balance in both sagittal and coronal planes is achieved through surgery. Only few studies about the coronal alignment correction with the kickstand rod were reported in the literature, until now. The aim of the present study was to describe clinical and radiological outcomes of the Kickstand rod (KR) technique in a series of ASD patients with severe coronal malalignment after 1 year of follow-up. MATERIAL AND METHODS: Six patients affected by ASD with severe CM who underwent surgery between 2018 and 2019 were retrospectively analyzed. The mean follow up was 14 months. All patients had posterior-only approach with long pelvic-thoracic fixation according to the Kickstand rod technique. RESULTS: Postoperative alignment and pain numerical rating scale scores significantly improved. No instrumentation complications occurred. A coronal alignment improvement from a mean of 163 mm preoperatively to a mean of 32 mm postoperatively was observed. CONCLUSION: KR technique appears to be a safe and efficient way for coronal and sagittal imbalance correction in ASD patients. Although technically demanding, by using this technique good and stable radiological and functional outcomes are achieved especially in selected patients.

A Supersymmetric Hierarchical Model for Weakly Disordered 3d Semimetals.

In this paper, we study a hierarchical supersymmetric model for a class of gapless, three-dimensional, weakly disordered quantum systems, displaying pointlike Fermi surface and conical intersections of the energy bands in the absence of disorder. We use rigorous renormalization group methods and supersymmetry to compute the correlation functions of the system. We prove algebraic decay of the two-point correlation function, compatible with delocalization. A main technical ingredient is the multiscale analysis of massless bosonic Gaussian integrations with purely imaginary covariances, performed via iterative stationary phase expansions.

Biological enhancement of graft-tunnel healing in anterior cruciate ligament reconstruction.

The sites where graft healing occurs within the bone tunnel and where the intra-articular ligamentization process takes place are the two most important sites of biological incorporation after anterior cruciate ligament (ACL) reconstruction, since they help to determine the mechanical behavior of the femur-ACL graft-tibia complex. Graft-tunnel healing is a complex process influenced by several factors, such as type of graft, preservation of remnants, bone quality, tunnel length and placement, fixation techniques and mechanical stress. In recent years, numerous experimental and clinical studies have been carried out to evaluate potential strategies designed to enhance and optimize the biological environment of the graft-tunnel interface. Modulation of inflammation, tissue engineering and gene transfer techniques have been applied in order to obtain a direct-type fibrocartilaginous insertion of the ACL graft, similar to that of native ligament, and to accelerate the healing process of tendon grafts within the bone tunnel. Although animal studies have given encouraging results, clinical studies are lacking and their results do not really support the use of the various strategies in clinical practice. Further investigations are therefore needed to optimize delivery techniques, therapeutic concentrations, maintenance of therapeutic effects over time, and to reduce the risk of undesirable effects in clinical practice.