2,896 research outputs found

    Solving the time-dependent Schr\"odinger equation with absorbing boundary conditions and source terms in Mathematica 6.0

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    In recent decades a lot of research has been done on the numerical solution of the time-dependent Schr\"odinger equation. On the one hand, some of the proposed numerical methods do not need any kind of matrix inversion, but source terms cannot be easily implemented into this schemes; on the other, some methods involving matrix inversion can implement source terms in a natural way, but are not easy to implement into some computational software programs widely used by non-experts in programming (e.g. Mathematica). We present a simple method to solve the time-dependent Schr\"odinger equation by using a standard Crank-Nicholson method together with a Cayley's form for the finite-difference representation of evolution operator. Here, such standard numerical scheme has been simplified by inverting analytically the matrix of the evolution operator in position representation. The analytical inversion of the N x N matrix let us easily and fully implement the numerical method, with or without source terms, into Mathematica or even into any numerical computing language or computational software used for scientific computing.Comment: 15 pages, 7 figure

    Aspectos climáticos do noroeste fluminense, RJ.

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    Anuário científico da Escola Superior de Tecnologia da Saúde de Lisboa - 2016

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    A publicação do Anuário Científico da Escola Superior de Tecnologia da Saúde de Lisboa é uma constante desde o ano de 2011. Neste documento, onde foi coligida a produção científica dos docentes, não docentes e estudantes da ESTeSL, referente ao ano 2016, podem-se encontrar, não só, as publicações em livros ou revistas da especialidade, mas também os resumos das comunicações orais e dos pósteres apresentados em congressos e os trabalhos finais de mestrado e de licenciatura defendidos pelos estudantes da ESTeSL em 2016. Apesar dos constrangimentos financeiros, que continuaram, em 2016, a dificultar a dedicação dos docentes, não docentes e estudantes a atividades de investigação, a ESTeSL manteve um favorável desempenho científico. Este desempenho foi conseguido com a contribuição dos Departamentos da ESTeSL e/ou dos grupos de investigação que integram o Centro de Investigação em Saúde e Tecnologia da ESTeSL (CIST ESTeSL) e, simultaneamente, com uma significativa participação dos docentes e não docentes, da ESTeSL, que integram centros externos acreditados pela FCT. O Anuário Científico da ESTeSL começa a apresentar-se, cada vez mais, como a referência oficial da atividade científica da instituição, aumentando o número de dados submetidos e compilados neste documento.info:eu-repo/semantics/publishedVersio

    Heat capacity, thermal expansion and heat transport in the Han Blue (BaCuSi 4 O 10 ): Observation of structural phase transitions

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    a b s t r a c t Structural phase transitions at 87 K and 103 K are reported for single-crystalline Han Blue (BaCuSi 4 O 10 ) by means of high-resolution thermal-expansion, thermal conductivity and heat capacity measurements. The phase transition at 103 K results in differing lengths of the a and b lattice parameters, and thus a lowering of the crystallographic symmetry. Negative thermal-expansion coefficients are observed perpendicular to the c-axis over a wide temperature range The thermal conductivity is small, and decreases with temperature, both of which suggest strong scattering of heat-carrying phonons. The principle Grüneisen parameter within the plane and perpendicular to it was determined to be γ 1 ¼ À1.09 and γ 3 ¼1.06 at room temperature; the bulk Grüneisen parameter is γ¼0.10. The results are consistent with the presence of low-energy vibrations associated with the collective motions of CuO 4 and Si 4 O 10 polyhedral subunits

    Effect of an extract of Centella asiatica on the biodistribution of sodium pertechnetate (Na<sup>99m</sup>TcO<sub>4</sub>) and on the fixation of radioactivity on blood constituents

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    This study evaluates the effects of an acute treatment with a Centella asiatica (CA) extract on the biodistribution of the radiopharmaceutical Na99mTcO4 and on the fixation of technetium-99m on blood constituents. Wistar rats were treated with CA extract and, 1 hour after, Na99mTcO4 was administered; organs/tissues were withdrawn and weighted. The radioactivity was counted to calculate the percentage of activity per gram (%ATI/g). Also, blood samples were withdrawn, plasma (P), blood cells (BC), insoluble fraction (IF) and soluble fractions of P and BC were isolated and the radioactivity was counted to calculate the percentage of activity (%ATI). Data indicated that the acute treatment with CA extract changed significantly (p99mTcO4 and the fixation of the technetium-99m on blood constituents in an acute treatment

    Aspectos da produção, comercialização e desenvolvimento da cultura da pitaya no estado do Pará.

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    O presente artigo faz uma análise exploratória sobre a conjuntura de mercado da pitaya no Estado do Pará, investigando as oportunidades e desafios dessa fruteira na economia paraense. Para atingir o objetivo da pesquisa, realizou-se uma revisão de literatura sobre a cultura no cenário mundial, nacional e regional que dialogou com dados de produção do Instituto Brasileiro de Geografia e Estatística (IBGE) e informações de preço no varejo da Central de Abastecimento do Pará (CEASA-PA), referentes ao período de março de 2017 a janeiro de 2019, além de contar com observações de campo. Os preços foram deflacionados para o mês de fevereiro de 2019 pelo Índice Geral de Preços Disponibilidade Interna (IGP-DI). Observou-se que o Estado do Pará é o quarto maior produtor nacional de pitaya do País (com 10,47% da produção nacional), tendo o município de Tomé-Açu como principal polo produtivo (92,70 toneladas, em 2017). Por se tratar de uma fruta exótica, ainda existe um grande desconhecimento do mercado consumidor, havendo a necessidade de pesquisas de melhoramento genético e melhoria de fatores físico-químicos dos frutos, que tem efeito no sabor. Foi observado que as características gustativas do fruto têm grande influência na tomada de decisão de compra pelo novo consumidor, assim como o preço considerado caro que, atualmente, gira em torno de R$ 13,12/kg na CEASA-PA

    HPV testing as a triage for borderline or mild dyskaryosis on cervical cytology: results from the Sentinel Sites study

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    BACKGROUND: Earlier pilot studies of human papillomavirus (HPV) triage concluded that HPV triage was feasible and cost-effective. The aim of the present study was to study the impact of wider rollout of HPV triage for women with low-grade cytology on colposcopy referral and outcomes. METHODS: Human papillomavirus testing of liquid-based cytology (LBC) samples showing low-grade abnormalities was used to select women for colposcopy referral at six sites in England. Samples from 10 051 women aged 25-64 years with routine call or recall cytology reported as borderline or mild dyskaryosis were included. RESULTS: Human papillomavirus-positive rates were 53.7% in women with borderline cytology and 83.9% in those with mild dyskaryosis. The range between sites was 34.8-73.3% for borderline cytology, and 73.4-91.6% for mild dyskaryosis. In the single site using both LBC technologies there was no difference in rates between the two technologies. The positive predictive value of an HPV test was 16.3% for CIN2 or worse and 6.1% for CIN3 or worse, although there was considerable variation between sites. CONCLUSION: Triaging women with borderline cytological abnormalities and mild dyskaryosis with HPV testing would allow approximately a third of these women to be returned immediately to routine recall, and for a substantial proportion to be referred for colposcopy without repeat cytology. Variation in HPV-positive rates results in differing colposcopy workload. British Journal of Cancer (2011) 105, 983-988. doi:10.1038/bjc.2011.326 www.bjcancer.com Published online 6 September 2011 (C) 2011 Cancer Research U
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