Treating some solid state problems with the Dirac equation

The ambiguity involved in the definition of effective-mass Hamiltonians for nonrelativistic models is resolved using the Dirac equation. The multistep approximation is extended for relativistic cases allowing the treatment of arbitrary potential and effective-mass profiles without ordering problems. On the other hand, if the Schrodinger equation is supposed to be used, our relativistic approach demonstrate that both results are coincidents if the BenDaniel and Duke prescription for the kinetic-energy operator is implemented. Applications for semiconductor heterostructures are discussed.Comment: 06 pages, 5 figure

On the aerodynamics of an enclosed-wheel racing car: an assessment and proposal of add-on devices for a fourth, high-performance configuration of the DrivAer model

A modern benchmark for passenger cars – DrivAer model – has provided significant contributions to aerodynamics-related topics in automotive engineering, where three categories of passenger cars have been successfully represented. However, a reference model for highperformance car configurations has not been considered appropriately yet. Technical knowledge in motorsport is also restricted due to competitiveness in performance, reputation and commercial gains. The consequence is a shortage of open-access material to be used as technical references for either motorsport community or academic research purposes. In this paper, a parametric assessment of race car aerodynamic devices are presented into four groups of studies. These are: (i) forebody strakes (dive planes), (ii) front bumper splitter, (iii) rear-end spoiler, and (iv) underbody diffuser. The simplified design of these add-ons focuses on the main parameters (such as length, position, or incidence), leading to easier manufacturing for experiments and implementation in computational studies. Consequently, a proposed model aims to address enclosed-wheel racing car categories, adapting a simplified, 35% scaled-model DrivAer Fastback shape (i.e. smooth underbody, no wheels, and with side mirrors). Experimental data were obtained at the 8ft x 6ft Cranfield Wind Tunnel using an internal balance for force and moment measurements. The aerodynamic performance of each group of add-on was assessed individually in a range of ride heights over a moving belt. All cases represent the vehicle at a zero-yaw condition, Reynolds number (car length-based) of 4.2 × 106 and Mach number equal to 0.12. The proposed high-performance configuration (DrivAer hp-F) was tested and a respective Reynolds number dependency study is also provided. In line with the open-access concept of the DrivAer model, the CAD geometry and experimental data will be made available online to the international community to support independent studies

Wigner phase space distribution as a wave function

We demonstrate that the Wigner function of a pure quantum state is a wave function in a specially tuned Dirac bra-ket formalism and argue that the Wigner function is in fact a probability amplitude for the quantum particle to be at a certain point of the classical phase space. Additionally, we establish that in the classical limit, the Wigner function transforms into a classical Koopman-von Neumann wave function rather than into a classical probability distribution. Since probability amplitude need not be positive, our findings provide an alternative outlook on the Wigner function's negativity.Comment: 6 pages and 2 figure

Sinusoidal growth, recruitment, mortality, yield-per-recruit analysis of Buried fan scallop Mimachlamys funebris (Reeve, 1853) and their implications for mariculture

This study described the growth, mortality, recruitment pattern and exploitation rate of the Buried fan scallop (Mimachlamys funebris) in Asid Gulf, Philippines. Monthly length-frequency data (N=3988) from April 2018 to March 2019 were used to examine population parameters using FISAT II. Two estimates of natural mortalities were used to compare variability of limit exploitation rates. Modelling through the oscillating von Bertalanffy growth function revealed that the species is fast growing (K=1.1 year–1) attaining SH∞ of 10.5 cm. Adequacy in the use of the sinusoidal version of the growth formula hinges on the mean annual temperature difference reported in the gulf to be 2°C. Recruitment pattern was continuous and bimodal throughout the year with two high pulses in April–May and September consistent with the reproductive seasonality reported for congeneric species. Fishing mortality coefficients (4.26 and 4.82 year–1) were higher than the natural mortality coefficients (0.543 and 1.1 year–1). Yield and biomass-per-recruit analysis showed that the current exploitation rates are 112% (Ecurr1 = 0.90) and 92% (Ecurr2 = 0.80) higher than the biological reference points adopted for the study particularly E50. These results demonstrate that M. funebris stock is overexploited, which necessitates effective management measures including mariculture

Calculation of the unitary part of the Bures measure for N-level quantum systems

We use the canonical coset parameterization and provide a formula with the unitary part of the Bures measure for non-degenerate systems in terms of the product of even Euclidean balls. This formula is shown to be consistent with the sampling of random states through the generation of random unitary matrices

Pleurodese experimental induzida por antibióticos (macrolídeos e quinolonas)

PURPOSE: Chemical pleurodesis is a therapeutic tool for the treatment of recurrent pleural effusions, mainly those of neoplastic etiology. In the past, tetracycline was the sclerosant agent of choice in clinical practice, but presently, there is no consensus about an ideal agent. The aim of this study was to evaluate the effectiveness of macrolides (azithromycin and clarithromycin) or quinolones (levofloxacin and gatifloxacin) in inducing experimental pleurodesis in rabbits. METHOD: Forty New Zealand rabbits randomized into groups of 10 received (at a total volume of 2 mL for each animal) 1 of the 4 drugs by intrapleural injection. After 28 days, the animals were euthanized and the pleural cavity was evaluated macroscopically and microscopically. RESULTS: The intensity of the macroscopic adhesions was mild in all groups. On microscopic analysis, minimal pleural fibrosis and inflammation were observed in all animals. CONCLUSION: The macrolides (azithromycin or clarithromycin) and the quinolones (levofloxacin or gatifloxacin) when injected into the normal pleural space of rabbits are not effective in promoting pleurodesis. Additional research is required to identify sclerosing agents capable of inducing pleurodesis.OBJETIVO: A pleurodese química representa uma ferramenta terapêutica utilizada no tratamento dos processos pleurais recidivantes, principalmente nos derrames neoplásicos. A escolha do melhor esclerosante pleural é ainda motivo de controvérsia, não havendo consenso com relação ao agente considerado ideal. O objetivo deste estudo é avaliar a efetividade dos macrolídeos (azitromicina e claritromicina) e das quinolonas (levofloxacina e gatifloxacina) na indução de pleurodese experimental em coelhos. MÉTODOS: Quarenta animais randomizados em grupos de 10, receberam, em volume total de 2 mL, estas drogas através de injeção intrapleural. RESULTADOS: Após 28 dias, os animais foram sacrificados sendo avaliada a cavidade pleural. A intensidade das aderências macroscópicas assim como da fibrose e da inflamação observadas à microscopia foi discreta tanto no grupo que recebeu macrolídeos quanto naquele que recebeu quinolonas. CONCLUSÃO: Azitromicina, Claritromicina, Levofloxacina e Gatifloxacina quando injetados na cavidade pleural de coelhos, não são eficazes na indução de pleurodese. Novas pesquisas devem ser realizadas com o intuito de identificar agentes esclerosantes capazes de produzir sínfise pleural

Activation Of The Low Molecular Weight Protein Tyrosine Phosphatase In Keratinocytes Exposed To Hyperosmotic Stress

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Herein, we provide new contribution to the mechanisms involved in keratinocytes response to hyperosmotic shock showing, for the first time, the participation of Low Molecular Weight Protein Tyrosine Phosphatase (LMWPTP) activity in this event. We reported that sorbitol-induced osmotic stress mediates alterations in the phosphorylation of pivotal cytoskeletal proteins, particularly Src and cofilin. Furthermore, an increase in the expression of the phosphorylated form of LMWPTP, which was followed by an augment in its catalytic activity, was observed. Of particular importance, these responses occurred in an intracellular milieu characterized by elevated levels of reduced glutathione (GSH) and increased expression of the antioxidant enzymes glutathione peroxidase and glutathione reductase. Altogether, our results suggest that hyperosmostic stress provides a favorable cellular environment to the activation of LMWPTP, which is associated with increased expression of antioxidant enzymes, high levels of GSH and inhibition of Src kinase. Finally, the real contribution of LMWPTP in the hyperosmotic stress response of keratinocytes was demonstrated through analysis of the effects of ACP1 gene knockdown in stressed and non-stressed cells. LMWPTP knockdown attenuates the effects of sorbitol induced-stress in HaCaT cells, mainly in the status of Src kinase, Rac and STAT5 phosphorylation and activity. These results describe for the first time the participation of LMWPTP in the dynamics of cytoskeleton rearrangement during exposure of human keratinocytes to hyperosmotic shock, which may contribute to cell death.103Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2006/07315-3]CNPq [PQ-2

Quasi-stationary simulations of the directed percolation universality class in d = 3 dimensions

We present quasi-stationary simulations of three-dimensional models with a single absorbing configuration, namely the contact process (CP), the susceptible-infected-susceptible (SIS) model and the contact replication process (CRP). The moment ratios of the order parameters for the DP class in three dimensions were set up using the well established SIS and CP models. We also show that the mean-field exponent for d = 3 reported previously for the CRP (Ferreira 2005 Phys. Rev. E 71 017104) is a transient observed in the spreading analysis