Contact interaction in an unitary ultracold Fermi gas

An ultracold Fermi atomic gas at unitarity presents universal properties that in the diluted limit can be well described by a contact interaction. By employing a guide function with correct boundary conditions and making simple modifications to the sampling procedure we are able to handle for the first time a true contact interaction in a quantum Monte Carlo calculation. The results are obtained with small variances. Our calculations for the Bertsch and contact parameters are in excellent agreement with published experiments. The possibility of using a more faithfully description of ultracold atomic gases can help uncover features yet unknown of the ultracold atomic gases. In addition, this work paves the way to perform quantum Monte Carlo calculations for systems interacting with contact interactions, where in many cases the description using potentials with finite effective range might not be accurate

Avaliação de genótipos de mandioca da reserva extrativista Cazumbá-Iracema, Acre.

A mandioca é o principal produto agrícola do Acre, cultivado para geração de renda e segurança alimentar, sendo tipicamente de exploração familiar. Este trabalho teve como objetivo avaliar genótipos de mandioca na Reserva Extrativista do Cazumbá-Iracema, localizada no município de Sena Madureira, AC. Foram instalados três experimentos nas localidades Cazumbá, Cuidado e Alto Caeté, utilizando-se o delineamento inteiramente casualizado com quatro repetições. Foram avaliados; número de raízes por planta, percentagem de amido e massa seca de raízes, produtividade e rendimento de farinha de mandioca. Foi realizada a avaliação de oito genótipos nas localidades de Cazumbá e Cuidado e de seis genótipos em Alto Caeté, analisando conjuntamente os quatro genótipos Panatí, Araçá, Colonial e Pirarucu que foram plantados nas três localidades. Os dados foram submetidos a análise de variância e para os efeitos significativos, aplicou-se o teste de Tukey e Scott-Knott a 5 % de probabilidade. A cultivar Pirarucu, que é a mais plantada na reserva, foi ogenótipo que apresentou melhor desempenho quanto a produtividade e rendimento de farinha

La historia de la ciencia como herramienta para la enseñanza de física en secundaria : un ejemplo en calor y temperatura

In this work we suggest and analyze some stages of a course on heat and temperature which knowledge of the past of the ideas and the solution provided can enable a better understanding of the content. The hypothesis that guided the planning of activities was that the scientific content studied throughout its history comes closer to the cognitive universe, not only of the student, but of man himself

Ensaio de atividade de B-galactosidase em Gluconacetobacter diazotrophicus para estudos de expressão gênica.

Este Comunicado Técnico mostra a repetitibilidade de ensaios de atividade de ?-galactosidase, que foram padronizados com G. diazotrophicus, ilustrando sua utilidade em estudos de expressão gênica que envolvem fusões com o gene repórter lacZ. Os resultados mostrados neste Comunicado Técnico ilustram que o meio, as condições de cultivo e o ensaio de atividade de ?-galactosidase estabelecidos para G. diazotrophicus são reprodutíveis, e, portanto, válidos, sendo de grande valia para quantificar níveis de expressão gênica nessa importante bactéria constituinte do inoculante para cana-de-açúcar da Embrapa.bitstream/item/42760/1/COT123-09.pd

Zero-range Fermi gas along the BCS-BEC crossover

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPEG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE GOIÁSProperties of the ground state of an unpolarized ultracold Fermi gas along the BCS-BEC crossover are investigated by the variational and diffusion Monte Carlo methods. We apply the Wigner-Bethe-Peierls boundary condition in our calculations to avoid any bias from using an interatomic potential with finite effective range. Properties for several values of the scattering length are studied in the range -8 <= 1/ak(F) <= 4, including the unitary limit. The contact parameters as a function of scattering length are obtained by fitting the pair distribution functions for particles with different spins. The energies and contact parameters are in very good agreement with experimental data reported in the literature.100515FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPEG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE GOIÁSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPEG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE GOIÁS2016/17612-7Sem informaçãoThe authors acknowledge financial support from the Brazilian agencies Fundacao de Amparo a Pesquisa do Estado de Sao Paulo project (Proc. No. 2016/17612-7). Part of the computations was performed at the Centro Nacional de Processamento de Alto Desempenho em Sao Paulo. R.P. acknowledges the Fundacao de Amparo a Pesquisa do Estado de Goias and the computer resources of the Laboratorio de Computacao Cientifica - Universidade Federal de Goias. K.E.S. was supported by NSF Grant No. PHY-1404405

Zero-point Divacancy Concentration in the Shadow Wave-Function Model for Solid 4He

We address the issue of interaction between zero-point vacancies in solid 4He as described within the shadow wave-function model. Applying the reversible-work method and taking into account finite-size effects, we obtain a zero-point monovacancy concentration of (2.03 +- 0.02) 10^{-3}, which is slightly higher than the result due to Reatto et al. for the same model. Utilizing the same methodology, we then consider the divacancy, taking into account both the in-plane as well as out-of-plane configurations with respect to the basal plane. We find no significant anisotropy between both conformation. Furthermore, although there is a small binding tendency, the expected divacancy concentration is only ~4-5 times larger than the value expected in the absence of any clustering propensity, 2.5 10^{-5}. This result suggests that, within the employed model description, no vacancy aggregation leading to phase separation is to be expected in the ground state.Comment: 10 pages, 1 figur

Performance assessment of micropollutants removal from water using advanced oxidation processes

In a global climate change scenario, reliable access to clean and safe water for all remains a great worldwide challenge for the twenty first century, as one of the most ambitious targets of several Sustainable Development Goals (SDG) established in the UN Agenda 2030. The increasing presence in the urban aquatic ecosystems of priority pollutants and contaminants of emerging concerning (CECs) have brought new challenges to the existing water treatment systems (WTS) concerning with public health protection and the of drinking water sources preservation. Advanced oxidation processes (AOPs) have been widely studied because of their potential as a complementary or alternative process to conventional wastewater treatment. Several AOPs using nanomaterials as photocatalyst can be particularly effective in the degradation of many toxic micropollutants, and enhance the multifunctionality, versatility and sustainability of WTS. This work presents a synthesis of the major results obtained in several pilot and lab-scale studies aiming to assess the performance of different low-cost catalytic processes used for antibiotic and pesticide removal. For each photo-oxidation reactors, different test scenarios are defined in order to evaluate the effects of several abiotic and hydraulic parameters on process kinetics and removal efficiencies. The experimental results were very promising, because antibiotic removal efficiencies achieved the maximum value of 96% for the photo-oxidation by water columns with suspended TiO2 nanoparticles, and 98% for the photocatalytic filtration performed by a porous medium coated with TiO2. In the photoelectrocatalytic reactor, the atrazine concentration has been fully removed for reaction times between 35 and 95 minutes.(undefined