Prospects and status of quark mass renormalization in three-flavour QCD

We present the current status of a revised strategy to compute the running of renormalized quark masses in QCD with three flavours of massless O(a) improved Wilson quarks. The strategy employed uses the standard finite-size scaling method in the Schr\"odinger functional and accommodates for the non-perturbative scheme-switch which becomes necessary at intermediate renormalized couplings as discussed in [arXiv:1411.7648].Comment: 7 pages, 3 figures, 1 table; Proceedings of the 33rd International Symposium on Lattice Field Theory, 14-18 July 2015, Kobe, Japa

Raman-scattering study of the phonon dispersion in twisted bi-layer graphene

Bi-layer graphene with a twist angle \theta\ between the layers generates a superlattice structure known as Moir\'{e} pattern. This superlattice provides a \theta-dependent q wavevector that activates phonons in the interior of the Brillouin zone. Here we show that this superlattice-induced Raman scattering can be used to probe the phonon dispersion in twisted bi-layer graphene (tBLG). The effect reported here is different from the broadly studied double-resonance in graphene-related materials in many aspects, and despite the absence of stacking order in tBLG, layer breathing vibrations (namely ZO' phonons) are observed.Comment: 18 pages, 4 figures, research articl

Metallochaperones Are Needed for Mycobacterium tuberculosis and Escherichia coli Nicotinamidase-Pyrazinamidase Activity.

Mycobacterium tuberculosis nicotinamidase-pyrazinamidase (PZAse) is a metalloenzyme that catalyzes conversion of nicotinamide-pyrazinamide to nicotinic acid-pyrazinoic acid. This study investigated whether a metallochaperone is required for optimal PZAse activity. M. tuberculosis and Escherichia coli PZAses (PZAse-MT and PZAse-EC, respectively) were inactivated by metal depletion (giving PZAse-MT-Apo and PZAse-EC-Apo). Reactivation with the E. coli metallochaperone ZnuA or Rv2059 (the M. tuberculosis analog) was measured. This was repeated following proteolytic and thermal treatment of ZnuA and Rv2059. The CDC1551 M. tuberculosis reference strain had the Rv2059 coding gene knocked out, and PZA susceptibility and the pyrazinoic acid (POA) efflux rate were measured. ZnuA (200 μM) achieved 65% PZAse-EC-Apo reactivation. Rv2059 (1 μM) and ZnuA (1 μM) achieved 69% and 34.3% PZAse-MT-Apo reactivation, respectively. Proteolytic treatment of ZnuA and Rv2059 and application of three (but not one) thermal shocks to ZnuA significantly reduced the capacity to reactivate PZAse-MT-Apo. An M. tuberculosis Rv2059 knockout strain was Wayne positive and susceptible to PZA and did not have a significantly different POA efflux rate than the reference strain, although a trend toward a lower efflux rate was observed after knockout. The metallochaperone Rv2059 restored the activity of metal-depleted PZAse in vitro Although Rv2059 is important in vitro, it seems to have a smaller effect on PZA susceptibility in vivo. It may be important to mechanisms of action and resistance to pyrazinamide in M. tuberculosis Further studies are needed for confirmation.IMPORTANCE Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis and remains one of the major causes of disease and death worldwide. Pyrazinamide is a key drug used in the treatment of tuberculosis, yet its mechanism of action is not fully understood, and testing strains of M. tuberculosis for pyrazinamide resistance is not easy with the tools that are presently available. The significance of the present research is that a metallochaperone-like protein may be crucial to pyrazinamide's mechanisms of action and of resistance. This may support the development of improved tools to detect pyrazinamide resistance, which would have significant implications for the clinical management of patients with tuberculosis: drug regimens that are appropriately tailored to the resistance profile of a patient's individual strain lead to better clinical outcomes, reduced onward transmission of infection, and reduction of the development of resistant strains that are more challenging and expensive to treat

Finding critical points using improved scaling Ansaetze

Analyzing in detail the first corrections to the scaling hypothesis, we develop accelerated methods for the determination of critical points from finite size data. The output of these procedures are sequences of pseudo-critical points which rapidly converge towards the true critical points. In fact more rapidly than previously existing methods like the Phenomenological Renormalization Group approach. Our methods are valid in any spatial dimensionality and both for quantum or classical statistical systems. Having at disposal fast converging sequences, allows to draw conclusions on the basis of shorter system sizes, and can be extremely important in particularly hard cases like two-dimensional quantum systems with frustrations or when the sign problem occurs. We test the effectiveness of our methods both analytically on the basis of the one-dimensional XY model, and numerically at phase transitions occurring in non integrable spin models. In particular, we show how a new Homogeneity Condition Method is able to locate the onset of the Berezinskii-Kosterlitz-Thouless transition making only use of ground-state quantities on relatively small systems.Comment: 16 pages, 4 figures. New version including more general Ansaetze basically applicable to all case

Automated theorem proving for the systematic analysis of an infusion pump

This paper describes the use of an automated theorem prover to analyse properties of interactive behaviour. It offers an alternative to model checking for the analysis of interactive systems. There are situations, for example when demonstrating safety, in which alternative complementary analyses provide assurance to the regulator. The rigour and detail offered by theorem proving makes it possible to explore features of the design of the interactive system, as modelled, beyond those that would be revealed using model checking. Theorem proving can also speed up proof in some circumstances. The paper illustrates how a theory generated as a basis for theorem proving (using PVS) was developed systematically from a MAL model used to model check the same properties. It also shows how the CTL properties used to check the original model can be translated into theorems.CHI+MED, EPSRC research grant EP/G059063/

Quantum criticality as a resource for quantum estimation

We address quantum critical systems as a resource in quantum estimation and derive the ultimate quantum limits to the precision of any estimator of the coupling parameters. In particular, if L denotes the size of a system and \lambda is the relevant coupling parameters driving a quantum phase transition, we show that a precision improvement of order 1/L may be achieved in the estimation of \lambda at the critical point compared to the non-critical case. We show that analogue results hold for temperature estimation in classical phase transitions. Results are illustrated by means of a specific example involving a fermion tight-binding model with pair creation (BCS model).Comment: 7 pages. Revised and extended version. Gained one author and a specific exampl

Bilateral laparoscopic synchronous adrenalectomy in bilateral pheochromocytoma: experience in 8 patients

Indexación: Web of Science; ScieloAim: To evaluate 8 cases of bilateral pheochromocytoma and laparoscopic synchronous treatment. Patients and Methods: From May 1999 to May 2010, 8 patients with bilateral pheochromocytoma were found. A complete preoperative workup was done. Results: We perform 8 transperitoneal laparoscopic bilateral synchronous adrenalectomy. There was no open converted procedure. Mean operative time was 184.37 min. (range 95 to 300 min). Mean hospital stay was 3.8 days (range 3 to 5 days). Mean blood loss was 191.25 ml (range 0 to 500 min). In 7 cases the histopathological result was of pheochromocytoma and 1 as a malignant pheochomocytoma based on its histology. Conclusions: With very well establish diagnostic disease, an appropriate anesthetic strategy and as surgical skills, laparoscopic bilateral synchronic adrenalectomy is a feasible and safe surgical technique for bilateral pheochromocytomas.Introducción: La incidencia del feocromocitoma varía entre un 0,005 y un 0,1% y de estos sólo un 10% se presenta en forma bilateral. El objetivo de este trabajo es presentar nuestra experiencia en adrenalectomía laparoscópica bilateral sincrónica en pacientes con diagnóstico de feocromocitoma bilateral. Se revisa la literatura y se analizan nuestros resultados. Material y Métodos: Se realiza una revisión retrospectiva de todos los pacientes sometidos a una adrenelectomía laparoscópica bilateral sincrónica entre mayo de 1999 y mayo de 2010, con diagnóstico de un feocromocitoma bilateral. Todos los pacientes fueron estudiados con medición de catecolaminas plasmáticas y urinarias y estudio por imágenes. Resultados: Se realizaron 8 adrenelectomías laparoscópicas bilaterales sincrónicas. El tiempo promedio de cirugía fue de 184 min (rango 95-300 min). La estadía intrahospitalaria media fue de 3,8 días (rango de 3-5 días). El promedio de sangrado fue de 83 ml (rango 0-500 ml). El diagnóstico histopatológico fue de feocromocitoma en todas las muestras, en un caso se diagnosticó un feocromocitoma maligno. No hubo conversión a cirugía abierta. Conclusiones: La adrene-lectomía laparoscópica bilateral sincrónica para feocromocitomas bilaterales es un procedimiento seguro y de baja morbilidad, realizada por un cirujano con experiencia en cirugía laparoscópica. Es necesario tener previamente el diagnóstico de certeza para el manejo anestésico y postquirúrgico adecuado para estos pacientes.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-40262011000600005&nrm=is