Renormalization group analysis of the three-dimensional Gross-Neveu model at finite temperature and density

The Renormalization Group flow equations obtained by means of a proper time regulator are used to analyze the restoration of the discrete chiral symmetry at non-zero density and temperature in the Gross-Neveu model in d=2+1 dimensions. The effects of the wave function renormalization of the auxiliary scalar field on the transition have been studied. The analysis is performed for a number of fermion flavors N_f=12 and the limit of large N_f is also considered. The results are compared with those coming from lattice simulations.Comment: Latex file, 12 pages, 2 eps figures, minor changes, added references, published versio

A universal scaling law for the evolution of granular gases

Dry, freely evolving granular materials in a dilute gaseous state coalesce into dense clusters only due to dissipative interactions. This clustering transition is important for a number of problems ranging from geophysics to cosmology. Here we show that the evolution of a dilute, freely cooling granular gas is determined in a universal way by the ratio of inertial flow and thermal velocities, that is, the Mach number. Theoretical calculations and direct numerical simulations of the granular Navier--Stokes equations show that irrespective of the coefficient of restitution, density or initial velocity distribution, the density fluctuations follow a universal quadratic dependence on the system's Mach number. We find that the clustering exhibits a scale-free dynamics but the clustered state becomes observable when the Mach number is approximately of $\mathcal{O}(1)$. Our results provide a method to determine the age of a granular gas and predict the macroscopic appearance of clusters

The Effect of Rules on Racially-Influenced Policing and Police Uses of Force

Public opinion polls have shown the public lacks confidence in U.S. police to use appropriate amounts of force and treat racial minorities fairly, which undermines police legitimacy and the quality of life of all citizens. Although rules have been shown to positively constrain police uses of force, researchers have not demonstrated the effect of rules on racially influenced policing (RIP). In 2005, the RIP directive which prohibits officers from using race as a factor in taking discretionary actions was promulgated in New Jersey. The purpose of this study was to determine through the theoretical lens of Lipsky\u27s street-level bureaucrat theory the influence of the RIP directive on municipal police officer uses of force upon non-Whites. A quantitative nonexperimental retrospective design was used to examine a stratified, proportionate random sample of 301 use of force reporting forms from municipal police agencies in one New Jersey county for a 5-year period before and after the enactment of the RIP directive. A binomial logistic regression indicated that the RIP directive had no influence on the use of force upon non-Whites. Suspect race did not significantly influence force outcomes. Scholarly implications include producing research based upon existing policy to better help inform evidence-based policymaking. Policy implications include police practitioners and policymakers actively monitoring officer uses of force for racial bias and broadening their examination to other issues affecting the problem of trust. Implications for social change include framing the problem within the public policy paradigm to promote political discourse, evidence-based decision making, and improved civilian oversight of the police, which could strengthen trust and police legitimacy

Proper time regulator and Renormalization Group flow

We consider some applications of the Renormalization Group flow equations obtained by resorting to a specific class of proper time regulators. Within this class a particular limit that corresponds to a sharpening of the effective width of the regulator is investigated and a procedure to analytically implement this limit on the flow equations is shown. We focus on the critical exponents determination for the O(N) symmetric scalar theory in three dimensions. The large N limit and some perturbative features in four dimensions are also analysed. In all problems examined the results are optimized when the mentioned limit of the proper time regulator is taken.Comment: 22 pages, 4 eps figure

Defect-Seeded Atomic Layer Deposition of Metal Oxides on the Basal Plane of 2D Layered Materials

Atomic layer deposition (ALD) on mechanically exfoliated 2D layered materials spontaneously produces network patterns of metal oxide nanoparticles in triangular and linear deposits on the basal surface. The network patterns formed under a range of ALD conditions and were independent of the orientation of the substrate in the ALD reactor. The patterns were produced on MoS2 or HOPG when either tetrakis(dimethylamido)titanium or bis(ethylcyclopentadienyl)manganese were used as precursors, suggesting that the phenomenon is general for 2D materials. Transmission electron microscopy revealed the presence, prior to deposition, of dislocation networks along the basal plane of mechanically exfoliated 2D flakes, indicating that periodical basal plane defects related to disruptions in the van der Waals stacking of layers, such as perfect line dislocations and triangular extended stacking faults networks, introduce a surface reactivity landscape that leads to the emergence of patterned deposition

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Fasa y-Li&#8322Sc&#8323(P0&#8324)&#8323merupakan material konduktor superionik yang dapat diaplikasikan sebagai baterai yang dapat diisi ulang (rechargeable). Ion Li ± dalam struktur y-Li&#8322Sc&#8323(P0&#8324) dapat mengalami migrasi dari posisi terisi ke posisi kosong. Penelitian ini telah memodelkan migrasi ion Li+dalam struktur y-Li&#8322Sc&#8323(P0&#8324)dengan menggunakan metode bond valence sum (BVS). Metode ini dapat memprediksi bilangan oksidasi suatu atom berdasarkan jarak dengan atom-atom tetangga. Source code berbasis BVS yang digunakan adalah JUMPITER yang mensimulasi efek gaya listrik eksternal yang bertindak pada ion litium sehingga nilai BVS litium dapat dipetakan terhadap jarak. Hasil simulasi menunjukkan bahwa konduksi ion Li+dapat terjadi pada arah [010], [101], dan [120]. Namun, lintasan konduksi ion Li+ lebih mudah terjadi pada arah [120] atau bidang ab dengan nilai maksimum BVS adalah 0,982. y-phase of Li&#8322Sc&#8323(P0&#8324)&#8323is a lithium super ionic conductor which can be applied as a rechargeable lithium battery . Lithium ions of y-Li&#8322Sc&#8323(P0&#8324) can migrate from occupied site to vacant site. In this research. simulation of Li+ ions migration in the structure of y-Li&#8322Sc&#8323(P0&#8324) carried out using bond valence sum (BVS) to predict the oxidation state of Li+ion based on the distance of the ion to neighboring atoms. BVS-based code used JUMPITER to simulate the effect of external electricalforce acting on the lithium ions to produce the lithium BVS value which can be mapped to the distance. The simulation results shows that Li+ ion conduction can be occurred on [010}. [101}. and [120} directions. However. the Li ion conduction pathway occur more easily in the direction of [120} or ab plane with the B VS maximum value is 0.982

Interactivity in the education of the engineering of the chemical reactions. An innovative proposal

Este artículo presenta la realización de una experiencia interactiva en la enseñanza de la Ingeniería de Reactores en la carrera de Ingeniería Química en la Universidad Nacional del Comahue, Argentina. Se basa en la utilización de Textos Interactivos, herramienta construida sobre la estructura del software 'Mathematica'. Específicamente, el texto que se propone en el trabajo corresponde a la enseñanza de Mecanismos de Reacción Química, presentándose los resultados obtenidos sobre la base de consideraciones pedagógicas. Sobre esta base, el uso de textos interactivos como herramienta en la enseñanza superior es enfáticamente recomendado.The student, nowadays, demands new pedagogic approaches, which implies a major use of the educational technology. The computer programs of modeling and calculation are available for the academic context. In this article it appears to an interactive text on Mechanisms of Chemical Reaction, developed with the software Mathematica (Wolfram, 1996), and the results of the evaluation that were obtained on having applied the above mentioned text. The pupils showed a major level of motivation in the development of the task with the alternative methodology that with the traditional class, and this motivation linked to the use of the software

First Results from the HDMS experiment in the Final Setup

The Heidelberg Dark Matter Search (HDMS) is an experiment designed for the search for WIMP dark matter. It is using a special configuration of Ge detectors, to efficiently reduce the background in the low-energy region below 100 keV. After one year of running the HDMS detector prototype in the Gran Sasso Underground Laboratory, the inner crystal of the detector has been replaced with a HPGe crystal of enriched $^{73}$Ge. The final setup started data taking in Gran Sasso in August 2000. The performance and the first results of the measurement with the final setup are discussed.Comment: 8 pages, revtex, 7 figures, Home Page of Heidelberg Non-Accelerator Particle Physics Group: http://www.mpi-hd.mpg.de/non_acc