291 research outputs found

    Higher Order Asymptotics of Decaying Solutions of some Generalized Burgers Equations

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    We study the large-time behavior of solutions to a generalized Burgers Equation, with initial zero mass data. Our main purpose is to present a modified version of the Renormalization Group map, which is able to provide the higher order asymptotic properties of the solution to the Cauchy problem of a class of nonlinear time-evolution problems.Comment: 25 page

    Projeto e implementação de um reator eletrônico microcontrolado, de elevado fator de potência, orientado a lâmpadas de vapor metálico

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    The analysis, design and implementation of a microcontroller-based electronic ballast to supply metal halide (MH) lamps are presented. The proposed power scheme is based on the integration of the buck and flyback converters. The former providing power factor correction and the latter controlling lamp power by supplying the lamp with a low frequency square waveform current, which is a convenient way to avoid acoustic resonances in high intensity discharge (HID) lamps. Both converters operate in discontinuous conduction mode (DCM), thus allowing the use of only one high-frequency switch and simplifying the control. The electronic ballast is digitally controlled by using a low cost microcontroller PIC16F684. The microcontroller performs all the necessary tasks during starting, warming-up and steady state, including closed loop control of lamp current and protections. Experimental results for a 35W MH lamp are presented.Este trabalho descreve a análise, o projeto e a implementação de um reator eletrônico para lâmpadas de vapor metálico (MH) baseado em microcontrolador. O circuito do reator se fundamenta na integração de um conversor buck com um conversor flyback. A tarefa de correção do fator de potência é realizada pela etapa buck, enquanto a etapa flyback controla a potência na lâmpada fornecendo uma corrente em onda quadrada de baixa freqüência. Este é um método adequado para se evitar o fenômeno da ressonância acústica, comum em lâmpadas de descarga de alta pressão (HID). Os dois estágios conversores operam no modo de condução descontínua (DCM), o que permite o uso de apenas um interruptor de alta freqüência simplificando o controle. O reator eletrônico é controlado digitalmente e emprega um microcontrolador de baixo custo PIC16F684. Este componente é programado para desempenhar todas as tarefas necessárias aos processos de ignição, aquecimento e regime permanente da lâmpada, respondendo também pelo controle em malha fechada da corrente na lâmpada e proteções convencionais. O artigo inclui resultados experimentais obtidos de um protótipo que alimenta uma lâmpada MH de 35W

    In vitro activities of natural products against oral Candida isolates from denture wearers

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    Background: Candida-associated denture stomatitis is a frequent infectious disease. Treatment of this oral condition is difficult because failures and recurrences are common. The aim of this study was to test the in vitro antifungal activity of pure constituents of essentials oils. -- Methods: Eight terpenic derivatives (carvacrol, farnesol, geraniol, linalool, menthol, menthone, terpinen-4-ol, and aterpineol), a phenylpropanoid (eugenol), a phenethyl alcohol (tyrosol) and fluconazole were evaluated against 38 Candida isolated from denture-wearers and 10 collection Candida strains by the CLSI M27-A3 broth microdilution method. -- Results: Almost all the tested compounds showed antifungal activity with MIC ranges of 0.03-0.25% for eugenol and linalool, 0.03-0.12% for geraniol, 0.06-0.5% for menthol, a-terpineol and terpinen-4-ol, 0.03-0.5% for carvacrol, and 0.06-4% for menthone. These compounds, with the exception of farnesol, menthone and tyrosol, showed important in vitro activities against the fluconazole-resistant and susceptible-dose dependent Candida isolates. -- Conclusions: Carvacrol, eugenol, geraniol, linalool and terpinen-4-ol were very active in vitro against oral Candida isolates. Their fungistatic and fungicidal activities might convert them into promising alternatives for the topic treatment of oral candidiasis and denture stomatitis.Funding: this work has been funded in part by projects GIC07 123-IT-222-07 (Departamento de Educacion, Universidades e Investigacion, Gobierno Vasco), S-PR09UN01 and S-PR10UN03 (Saiotek 2009 and 2010, Departamento de Industria, Comercio y Turismo, Gobierno Vasco)

    Health-related quality of life and utilities in gastric premalignant conditions and malignant lesions: a multicentre study in a high prevalence country

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    BACKGROUND AND AIMS: A recent review of economic studies relating to gastric cancer revealed that authors use different tests to estimate utilities in patients with and without gastric cancer. Our aim was to determine the utilities of gastric premalignant conditions and adenocarcinoma with a single standardized health measure instrument. METHODS: Cross-sectional nationwide study of patients undergoing upper endoscopy (n=1,434) using the EQ-5D-5L quality of life (QoL) questionnaire. RESULTS: According to EQ-5D-5L, utilities in individuals without gastric lesions were 0.78 (95% confidence interval: 0.76-0.80), with gastric premalignant conditions 0.79 (0.77-0.81), previously treated for gastric cancer 0.77 (0.73-0.81) and with present cancer 0.68 (0.55-0.81). Self-reported QoL according to the visual analogue scale (VAS) for the same groups were 0.67 (0.66-0.69), 0.67 (0.66-0.69), 0.62 (0.59-0.65) and 0.62 (0.54-0.70) respectively. Utilities were consistently lower in women versus men (no lesions 0.71 vs. 0.78; premalignant conditions 0.70 vs. 0.82; treated for cancer 0.72 vs. 0.78 and present cancer 0.66 vs. 0.70). CONCLUSION: The health-related QoL utilities of patients with premalignant conditions are similar to those without gastric diseases whereas patients with present cancer show decreased utilities. Moreover, women had consistently lower utilities than men. These results confirm that the use of a single standardized instrument such as the EQ-5D-5L for all stages of the gastric carcinogenesis cascade is feasible and that it captures differences between conditions and gender dissimilarities, being relevant information for authors pretending to conduct further cost-utility analysis

    A policy-based framework for the determination of management options to protect vulnerable marine ecosystems under the EU deep-sea access regulations

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    Vulnerable marine ecosystems (VMEs) are particularly susceptible to bottom-fishing activity as they are easily disturbed and slow to recover. A data-driven approach was developed to provide management options for the protection of VMEs under the European Union “deep-sea access regulations.” A total of two options within two scenarios were developed. The first scenario defined VME closure areas without consideration of fishing activity. Option 1 proposed closures for the protection of VME habitats and likely habitat, while Option 2 also included areas where four types of VME geophysical elements were present. The second scenario additionally considered fishing. This scenario used VME biomass—fishing intensity relationships to identify a threshold where effort of mobile bottom-contact gears was low and unlikely to have caused significant adverse impacts. Achieving a high level of VME protection requires the creation of many closures (> 100), made up of many small (∼50 km2) and fewer larger closures (> 1000 km2). The greatest protection of VMEs will affect approximately 9% of the mobile fleet fishing effort, while closure scenarios that avoid highly fished areas reduce this to around 4–6%. The framework allows managers to choose the level of risk-aversion they wish to apply in protecting VMEs by comparing alternative strategies.En prensa2,27

    Secretome of the preimplantation human embryo by bottom-up label-free proteomics

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    Abstract A bottom-up label-free mass spectrometric proteomic strategy was used to analyse the protein profiles of the human embryonic secretome. Culture media samples used for embryonic culture of patients undergoing intracytoplasmic sperm injection cycles were selected as a test case for this exploratory proof-of-principle study. The media were stored after embryo transfer and then pooled into positive (n = 8) and negative (n =8) implantation groups. The absolute quantitative bottom-up technique employed a multidimensional protein identification technology based on separation by nano-ultra-high pressure chromatography and identification via tandem nanoelectrospray ionization mass spectrometry with dataindependent scanning in a hydrid QqTOF mass spectrometer. By applying quantitative bottom-up proteomics, unique proteins were found exclusively in both the positive-and negative-implantation groups, which suggest that competent embryos express and secrete unique biomarker proteins into the surrounding culture medium. The selective monitoring of these possible secretome biomarkers could make viable procedures using singleembryo transfer
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