961 resultados para Cuervo, Rufino, 1801-1853
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土壤对疏水性有机污染物的吸附实际上是土壤中矿物和有机质两部分共同作用的结果。土壤有机质的作用相当重要,因为与矿物相比,它通常对疏水性有机污染物具有较大的热力学亲合力。因此,土壤吸附有机污染物机理的研究主要是从土壤有机质的角度进行的。土壤有机质组成复杂,主要包括非特异性有机质和腐殖质,其中腐殖质约占有机质总量的50%-80%,包括胡敏酸、富里酸和胡敏素。早期的实验研究认为疏水性有机污染物在土壤有机质相中表现为线性分配,可以用平衡分配系数来描述。但是,随着实验研究的深入,平衡分配模型不能合理解释疏水性有机污染物的一些吸附特征,如非线性吸附、溶质竞争吸附以及解吸过程的滞后现象等。后来,Weber和Huang提出土壤吸附有机污染物的三端元模型。同时Pignatello和Xing提出双模式吸附模型。都认为土壤有机质存在明显的不均匀性,并且提出了“软碳”与“硬碳”的概念.
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传统看法认为石灰土是碳酸盐岩风化作用的产物,然而由于碳酸盐岩风化成土的特殊性,在宏观上难以直接甄别土层与母岩的关联性,以至引发出了很大的物源争议。因此,物质来源判别将是石灰土研究的关键内容。基于此,本文选择黔北遵义官坝、安顺天龙和贵阳花溪上水村4个石灰土剖面为实例,进行矿物组合、地球化学特征和粒度分布特征对比分析,旨在对分布十分广泛的贵州省石灰土的物质来源进行判别。结果显示:各剖面土层与下伏的碳酸盐岩具有明显的物源继承关系,石灰土是碳酸盐岩风化作用.酸不溶物残留、堆积的产物。
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2015
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The aim of this study was to conduct a systematic review to identify the randomized clinical studies that had investigated the following research question: Is the mandibular manipulation technique an effective and safe technique for the treatment of the temporomandibular joint disk displacement without reduction? the systematic search was conducted in the electronic databases: PubMed (Medical Publications), LILACS (Latin American and Caribbean Literature in Health Sciences), EMBASE (Excerpta Medica Database), PEDro (Physiotherapy Evidence Database), BBO (Brazilian Library of Odontology), CENTRAL (Library Cochrane), and SciELO (Scientific Electronic Library Online). the abstracts of presentations in physical therapy meetings were manually selected, and the articles of the ones that meet the requirements were investigated. No language restrictions were considered. Only randomized and controlled clinical studies were included. Two studies of medium quality fulfilled all the inclusion criteria. There is no sufficient evidence to support the effectiveness of the mandibular manipulation therapy, and therefore its use remains questionable. Being minimally invasive, this therapy is attractive as an initial approach, especially considering the cost of the alternative approaches. the analysis of the results suggests that additional high-quality randomized clinical trials are necessary on the topic, and they should focus on methods for data randomization and allocation, on clearly defined outcomes, on a priori calculated sample size, and on an adequate follow-up strategy.
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Rationale, aims and objectives Continuing health education is essential but challenged. in 2006, the Brazilian Cochrane Center, in collaboration with the Ministry of Health, launched a mass teaching initiative in evidence-based health care (EBH) for public-sector professionals via teleconferencing. This 152-hour, interactive EBH course has enrolled over 4500 professionals. This study aimed to assess the acquisition EBH knowledge and skills, as well as the attitudes and perceptions of a sample of students enrolled in the 2009 course via teleconferencing.Methods This prospective cohort study analyzed three aspects of this 152-hour EBH course that recruited 1040 volunteer participants, all public health sector employees working in 131 different hospitals or health agencies. Pre- and post-course tests using a modified version of the Berlin questionnaire with 20 multiple-choice questions were used to examine knowledge acquisition in a sample of 297 students. Tests were completed upon registration and at course completion. the research projects submitted by 872 participants were evaluated to assess skill acquisition. Answers to an anonymous survey assessed the attitudes and perceptions of 914 participants.Results There was a significant increase in knowledge from baseline to course completion (mean scores 8.2 +/- 3.3 versus 13.7 +/- 3.0, P < 0.001). Over 90% of the research projects were judged to be of adequate quality (appropriate rationale for the study, well-formulated research question and feasible execution); over 95% of the participants were satisfied with the course.Conclusion the Brazilian EBH course via teleconference improved the knowledge and skills of public-sector health professionals and was approved by the vast majority of students.
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Background and purpose: Accelerated partial breast irradiation (APBI) is the strategy that allows adjuvant treatment delivery in a shorter period of time in smaller volumes. This study was undertaken to assess the effectiveness and outcomes of APBI in breast cancer compared with whole-breast irradiation (WBI). Material and methods: Systematic review and meta-analysis of randomized controlled trials of WBI versus APBI. Two authors independently selected and assessed the studies regarding eligibility criteria. Results: Eight studies were selected. A total of 8653 patients were randomly assigned for WBI versus APBI. Six studies reported local recurrence outcomes. Two studies were matched in 5 years and only one study for different time of follow-up. Meta-analysis of two trials assessing 1407 participants showed significant difference in the WBI versus APBI group regarding the 5-year local recurrence rate (HR = 4.54, 95% CI: 1.78-11.61, p = 0.002). Significant difference in favor of WBI for different follow-up times was also found. No differences in nodal recurrence, systemic recurrence, overall survival and mortality rates were observed. Conclusions: APBI is associated with higher local recurrence compared to WBI without compromising other clinical outcomes. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
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The ptsH gene, encoding the phosphotransferase protein HPr, from Clostridium acetobutylicum ATCC 824 was identified from the genome sequence, cloned and shown to complement a ptsH mutant of Escherichia coli. The deduced protein sequence shares significant homology with HPr proteins from other low-GC gram-positive bacteria, although the highly conserved sequence surrounding the Ser-46 phosphorylation site is not well preserved in the clostridial protein. Nevertheless, the HPr was phosphorylated in an ATP-dependent manner in cell-free extracts of C. acetobutylicum. Furthermore, purified His-tagged HPr from Bacillus subtilis was also a substrate for the clostridial HPr kinase/phosphorylase. This phosphorylation reaction is a key step in the mechanism of carbon catabolite repression proposed to operate in B. subtilis and other low-GC gram-positive bacteria. Putative genes encoding the HPr kinase/phosphorylase and the other element of this model, namely the catabolite control protein CcpA, were identified from the C. acetobutylicum genome sequence, suggesting that a similar mechanism of carbon catabolite repression may operate in this industrially important organism.
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En Tomo V. 2 h. de grabados calcográficos representando monedas de Huesca.
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http://www.archive.org/details/memoirsandsermon00armsiala
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http://www.archive.org/details/westernmissionsa00smetrich
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http://moa.umdl.umich.edu/cgi/sgml/moa-idx?notisid=AAU8319 View book via University of Michigan
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Boston University Theology Library
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We consider type systems that combine universal types, recursive types, and object types. We study type inference in these systems under a rank restriction, following Leivant's notion of rank. To motivate our work, we present several examples showing how our systems can be used to type programs encountered in practice. We show that type inference in the rank-k system is decidable for k ≤ 2 and undecidable for k ≥ 3. (Similar results based on different techniques are known to hold for System F, without recursive types and object types.) Our undecidability result is obtained by a reduction from a particular adaptation (which we call "regular") of the semi-unification problem and whose undecidability is, interestingly, obtained by methods totally different from those used in the case of standard (or finite) semi-unification.
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A difficulty in lung image registration is accounting for changes in the size of the lungs due to inspiration. We propose two methods for computing a uniform scale parameter for use in lung image registration that account for size change. A scaled rigid-body transformation allows analysis of corresponding lung CT scans taken at different times and can serve as a good low-order transformation to initialize non-rigid registration approaches. Two different features are used to compute the scale parameter. The first method uses lung surfaces. The second uses lung volumes. Both approaches are computationally inexpensive and improve the alignment of lung images over rigid registration. The two methods produce different scale parameters and may highlight different functional information about the lungs.