956 resultados para 81 - Lingüística i llengües
Resumo:
A tuberculose multirresistente (MR) a drogas é uma séria ameaça à saúde pública devido à maiores complexidade, custo e efeitos colaterais do tratamento. Poucos estudos descreveram a epidemiologia molecular de isolados de <i>Mycobacterium tuberculosisi> MR no Brasil. Neste trabalho foi investigada a diversidade genética e mutações associadas à resistência a drogas de 99 isolados MR e 7 não MR coletados em um período de 8 anos e provenientes de 12 estados brasileiros. Esta investigação foi feita através da análise do polimorfismo de fragmentos de restrição do elemento de inserção IS6110 (IS6110-RFLP), spoligotyping e sequenciamento de regiões dos genes rpoB e katG que conferem resistência aos antibióticos rifampicina e isoniazida, respectivamente. Mutações nos genes katG e rpoB foram encontradas em 90,9% e 93% dos isolados MR analisados, respectivamente. Para o gene rpoB, 91,9% das mutações estavam contidas na região RRDR de 81-pb. Um total de 51 (51.5%), 23 (23.3%) e 11 (11.1%) isolados MR apresentaram mutações nos códons 531, 526 e 516, respectivamente. Com relação ao gene katG, foram encontradas mutações em 93% dos isolados MR analisados, sendo que 7 apresentaram mutações apenas na primeira região analisada (katG1). O codon 315 da segunda região analisada do gene katG (katG2) apresentou mutações em 82.8% dos isolados MR, sendo a maioria Ser315Thr. A região katG1 apresentou mutações em 30.3% dos isolados MR sendo a maioria deleção do códon 4. Pelo spoligotyping foi possível determinar que os isolados MR deste estudo pertencem a 5 diferentes famílias (com suas subfamílias) de M. tuberculosis circulantes no Brasil, onde as mais frequentemente encontradas foram: LAM (46%), T (17%) e H (12%). Nós observamos que uma das famílias, a EAI5, carrega mutações no códon 463 do gene katG, o que não ocorre para as demais. Além disso, entre nossos isolados foi identificada um isolado pertencente à cepa Beijing (extremamente virulenta), mas este fato não é alarmante já que se tratou de apenas um caso. Através de nossos dados foram descritos novos alelos mutados para os genes rpoB e katG. Com exceção da família X2, foi identificada uma região inicial do gene katG com alta frequência de mutações nos isolados MR. A análise por IS6110-RFLP revelou que 25 isolados formaram 11 grupos genotípicos enquanto 74 mostraram um padrão único de bandas. Esta alta taxa de polimorfismo indica aquisição independente de resistência entre nossos isolados. Para a família H, foi identificada uma inversão na freqüência de ocorrência de mutações no gene rpoB, sendo o códon 516 o mais mutado, seguido pelo 526 e 531. Os resultados deste estudo fornecem informações úteis para um melhor entendimento do espectro de mutações dos isolados MR de pacientes no Brasil. Nossos resultados também se tornam úteis no desenvolvimento de testes diagnósticos de tuberculose MR e para auxiliar no rastreamento da transmissão global desta doença.
Resumo:
本文研究所了四种钕化合物(茚基钕有机金属化合物C_9H_7NdCl_2·HCl·C_4H_8O,环戊二烯基钕有机金属化合物-C_5H_5NdCl_2·C_4H_8O,无水氯化钕络合物-NdCl_3·2C_4H_8O及NdCl_3·C_6H_5OH·C_4H_8O)与三异丁基铝(i-Ba_3Al)或一氢二异丁基铝(i-Bu_2AlH)所组成的二元催化体系中丁二烯聚合动力学。这些体系的动力学特点尚未被人们研究,通过实验揭示出一些新的规律,丰富了我们对稀土体系催化丁二烯聚合动力学的认识。研究中着重考察了聚合物活性链的变化条件,从而能较深刻地认识各体系的动力学特点,结果表明:C_9H_7NdCl_2·HCl·C_4H_8O,C_5H_5NdCl_2·C_4H_8O,NdCl_3·2C_4H_8O,NdCl_3·C_6H_5OH·C_4H_8O与i-Bu_2AlH所组成的二元催化体系中,当[Mo]=1.11克分子/升、[Nd]=1.12*10~(-4)克分子/升、[i-Bu_2AlH]\3.36*10~(-3)克分子/升、50 ℃聚合时为缓慢引发非稳态聚合反应。而当增加铝用量至[i-Bu_2AlH] = 6.72*10~(-3)克分子/升,C_9H_7NdCl_2·HCl·C_4H_8O体系转变为迅速引发稳态聚合反应,其余体系反应动力学行为无变化。各稀土钕催化体系动力学的差异主要是由配位体供电性不同产生的。当配位体供电性强时有利于降低稀土离子的正电荷,从而有利于烷基化反应和活性中心的形成和稳定,因此决定了各催化体系的不同动力学行为。C_9H_7NdCl_2·HCl·C_4H_8O体系当聚合温度、烷基铝浓度变化时以及Nd(naph)_3体系当温度变化时聚合物活性链状况会发生变化,从而改变了动力学行为。缓慢引发和迅速引发,稳态和非稳态间会发生转化而不是一成不变的。凝胶渗透色谱法应用于反应机理的研究不仅在理论上是可能的,在实践上是成功的。缓慢引发非稳态聚合(C_5H_5NdCl_2·C_4H_8O,NdCl_3·C_6H_5OH·C_4H_8O,NdCl_3·ZC_4H_8O),迅速引发非稳态聚合(Nd(naph)_3),迅速引发稳态聚合(C_9H_7NdCl_2·HCl·C_4H_8O)不同的动力学类型都具有不同的分子量分布特点。C_9H_7NdCl_2·HCl·C_4H_8O体系中丁二烯聚合速率方程为:K_p=K_p[C~*][M]. 50 ℃,[Nd]=1.12*10~(-4),[i-Bu_2AlH]=6.72*10~(-3)克分子/升条件下,丁二烯为快引发稳态聚合反应。此体系中活性中以浓度为2.43*10~(-6)克分子/升,催化剂有效利用率2%,链增长速率常数为81.42升/克分子,秒,聚合反应表观活化能为8.5±0.5千卡/克分子。聚合物顺-1,4结构均为98%左右。活性链平均寿命为7.22分钟。活性链对烷基铝的转移为主要链转移方式而对单体无明显转移。链转移速率常数为2.99升/克分子秒。
Resumo:
Nd(i-PrO)_2Cl-AlEt_3均相二元催化剂异戊二烯聚合动力学──Ⅲ.AlEt_3的链转移作用蔡小平,龚志,王佛松朱行洁,李秀华(中国科学院长春应用化学研究所长春130022)(吉林化工集团公司研究院吉林)关键词异戊二烯,聚合动力学,均相催化...
Resumo:
聚1-三甲硅基丙炔膜经紫外线辐照后其氧氮选择性提高,用XPS及水接触角法研究了膜的表面组成对透气性的影响。
Resumo:
This paper reviews the fingerprint classification literature looking at the problem from a double perspective. We first deal with feature extraction methods, including the different models considered for singular point detection and for orientation map extraction. Then, we focus on the different learning models considered to build the classifiers used to label new fingerprints. Taxonomies and classifications for the feature extraction, singular point detection, orientation extraction and learning methods are presented. A critical view of the existing literature have led us to present a discussion on the existing methods and their drawbacks such as difficulty in their reimplementation, lack of details or major differences in their evaluations procedures. On this account, an experimental analysis of the most relevant methods is carried out in the second part of this paper, and a new method based on their combination is presented.
Atmospheric neutrino oscillation analysis with subleading effects in Super-Kamiokande I, II, and III
Resumo:
We present a search for nonzero θ13 and deviations of sin2θ23 from 0.5 in the oscillations of atmospheric neutrino data from Super-Kamiokande I, II, and III. No distortions of the neutrino flux consistent with nonzero θ13 are found and both neutrino mass hierarchy hypotheses are in agreement with the data. The data are best fit at Δm2=2.1×10-3eV2, sin2θ13=0.0, and sin2θ23=0.5. In the normal (inverted) hierarchy θ13 and Δm2 are constrained at the one-dimensional 90% C.L. to sin2θ13<0.04(0.09) and 1.9(1.7)×10 -3<Δm2<2.6(2.7)×10-3eV2. The atmospheric mixing angle is within 0.407≤sin2θ23≤0.583 at 90% C.L. © 2010 The American Physical Society.
Resumo:
There is growing interest in the mating systems of sharks and their relatives (Class Chondrichthyes) because these ancient fishes occupy a key position in vertebrate phylogeny and are increasingly in need of conservation due to widespread overexploitation. Based on precious few genetic and field observational studies, current speculation is that polyandrous mating strategies and multiple paternity may be common in sharks as they are in most other vertebrates. Here, we test this hypothesis by examining the genetic mating system of the bonnethead shark, <i>Sphyrna tiburoi>, using microsatellite DNA profiling of 22 litters (22 mothers, 188 embryos genotyped at four polymorphic loci) obtained from multiple locations along the west coast of Florida. Contrary to expectations based on the ability of female <i>S. tiburoi> to store sperm, the social nature of this species and the 100% multiple paternity observed in two other coastal shark species, over 81% of sampled bonnethead females produced litters sired by a single male (i.e. genetic monogamy). When multiple paternity occurred in <i>S. tiburoi>, there was an indication of increased incidence in larger mothers with bigger litters. Our data suggest that sharks may exhibit complex genetic mating systems with a high degree of interspecific variability, and as a result some species may be more susceptible to loss of genetic variation in the face of escalating fishing pressure. Based on these findings, we suggest that knowledge of elasmobranch mating systems should be an important component of conservation and management programmes for these heavily exploited species.
Resumo:
El Ebro (1917-1936) was a magazine published in Barcelona by Aragonese emigrants at the beginning of the 20th century. It was the first experience of coexistence of different dialectal varieties of the Aragonese language in the same media. El Ebro was an experience that has gone virtually unnoticed in the recent history of one of the most minority languages, and with minor media presence, of Western Europe. In its pages El Ebro mixed dialects spoken in different regions of linguistic Aragonese area together with transcripts of medieval documents. At the same time, this newspaper raised debates about the language issue that they were truncated due to disappearance of the publication and the lack of theoretical realization
Resumo:
The origins of Sephardic press date back to the mid-20th century, when the influence of the Western world spread across the Sephardim communities of the East. The content of these newspapers was diverse: pieces of general interest, but also scientific, literary and humorous works, with various political orientations. These papers were published in different languages, writing styles and alphabets. Those to be analysed here, however, were published in aljamiado Judeo-Spanish: three papers from Smyrna and one from Salonica. Throughout this work we will focus on the different obstacles and difficulties the editors and publishers of this Ottoman Sephardic press had to face to bring their publications to light.
Resumo:
This paper presents and analyzes the first literary-journalistic chronicle writen and published by Miguel Hernández: “Defensa de Madrid. Madrid y las ciudades de Retaguardia”, during the Spanish Civil War (1936-1939). This chronicle is the first one of a series establishing a new and personal type of journalism: literary chronicles –poetical and political-. Miguel Hernandez published his masterpieces in different newspapers as a war reporter, with his own name and with a pen-name, playing roles of director and political commissar in different newspapers in the war-trenches. Thematically, this first article shows his personal and political engagement, as well as his desire and strategy to protect the capital city of Spain: Madrid. Methodologically, the analysis is an approached to linguistics in social sciences, which presents some of the personal characteristics and style of the chronist Miguel Hernández. Thus, it becomes patent that the so-called New Journalism (narrative and literary), which flourished in the 70s, had already been deeply and efficiently practiced by Miguel Hernández 40 years before. That is the reason why Miguel Hernández deserves to be added to the well-known collective of chronicle writers that have already been rescued to this moment. His literary style and quality are installing him in a outstanding position as well as pioneer of the genre nowadays known as New Journalism that in his case, it is politically engaged
Resumo:
Size at onset of maturity (SOM) was estimated for both male and female Nephrops from primary sexual characteristics and morphometric traits. SOM estimated from primary sexual characteristics based on histological examination of the gonad ranged from 15.1 mm carapace length (CL) in males to 22.9 mm CL in females. Nephrops morphometric maturity, or change in allometric growth of body parts, was estimated from appendix masculina and cutter claw lengths in males and abdomen width in females from two sites in the Irish Sea. Two regression techniques were used to estimate morphometric maturity. Estimated SOM from morphometric characteristics ranged from 23.2 to 27.6 mm CL in females and from 25.9 to 31.0 mm CL in males. Spatial variation in SOM was observed in Nephrops from different parts of the Irish Sea.
Resumo:
Sudan dyes have been found to be added to chilli and chilli products for illegal colour enhancement purposes. Due to the possible carcinogenic effect, they are not authorized to be used in food in the European Union or the USA. However, over the last few years, many products imported from Asian and African countries have been reported via the Rapid Alert System for Food and Feed in the European Union to be contaminated with these dyes. In order to provide fast screening method for the detection of Sudan I (SI), which is the most widely abused member of Sudan dyes family, a unique (20 min without sample preparation) direct disequilibrium enzyme-linked immunosorbent assay (ELISA) was developed. The assay was based on polyclonal antibodies highly specific to SI. A novel, simple gel permeation chromatography clean-up method was developed to purify extracts from matrices containing high amounts of fat and natural pigments, without the need for a large dilution of the sample. The assay was validated according to the Commission Decision 2002/657/EC criteria. The detection capability was determined to be 15 ng g(-1) in sauces and 50 ng g(-1) in spices. The recoveries found ranged from 81% to 116% and inter- and intra-assay coefficients of variation from 6% to 20%. The assay was used to screen a range of products (85 samples) collected from different retail sources within and outside the European Union. Three samples were found to contain high amounts (1,649, 722 and 1,461 ng g(-1)) of SI by ELISA. These results were confirmed by liquid chromatography-tandem mass spectrometry method. The innovative procedure allows for the fast, sensitive and high throughput screening of different foodstuffs for the presence of the illegal colorant SI.
Long-chain haloalkanes are incorporated into fatty-acids by <i>Rhodococcus rhodochrous i>NCIMB-13064
Resumo:
The fatty acid composition of the cellular lipids of Rhodococcus rhodochrous NCIMB 13064 grown on various long-chain haloalkanes has been investigated and the influence of halogen substituents, carbon chain length and the position of halogen substitution in the growth substrate explored. Of the total fatty acids present in cells grown on 1-chloro-, 1-bromo- and 1-iodohexadecane, 75, 90 and 81%, respectively, were substituted in the omega-position by the corresponding halogen but only 1% of the fatty acids present after growth on 1-fluorotetradecane were fluorinated in this position. The extent of the halofatty acid incorporation with different halogen substituents in the growth substrate appears to reflect the degree to which oxygenase attack is restricted to the non-halogenated end of the haloalkane. Studies of the fatty acid composition of cells after growth on a series of 1-chloroalkanes containing an even number of carbon atoms between C-10 and C-18 indicated chlorofatty acid incorporation from C-12 to C-18 substrates at levels ranging from 21% with C-12 to 75% with C-16. The chlorofatty acids formed by initial oxidation of the chloroalkane were chain-lengthened or chain-shortened by from two to eight carbon atoms, with accompanying desaturation in some instances. Substantial quantities of a methyl-branched C-19:0 chlorofatty acid were also present with several chloroalkane substrates, When the fatty acid composition of cells after growth on 1-bromoalkanes containing an odd number of carbon atoms between C-11 and C-17 was examined, the incorporation of bromofatty acids was observed with C-13, C-15 and C-17 substrates; a maximum of 76% was recorded for the C-15 bromoalkane. As with even chain-length chloroalkanes, both chain-lengthening and -shortening occurred predominantly via two-carbon units so that most bromoacids present possessed an odd number of carbon atoms, When 1-bromododecane or 2-bromododecane were substrates, overall incorporations of bromofatty acids into the lipid fraction were very similar, demonstrating that the position of halogen substitution in the haloalkane was not critical in determining the extent of incorporation of the haloacids into cellular lipids. The results of the study indicate a mechanism by which degradation products of chlorinated paraffins could enter the biological food chain.
Resumo:
PURPOSE: Several studies observed a female advantage in the prognosis of cutaneous melanoma, for which behavioral factors or an underlying biologic mechanism might be responsible. Using complete and reliable follow-up data from four phase III trials of the European Organisation for Research and Treatment of Cancer (EORTC) Melanoma Group, we explored the female advantage across multiple end points and in relation to other important prognostic indicators. PATIENTS AND METHODS: Patients diagnosed with localized melanoma were included in EORTC adjuvant treatment trials 18832, 18871, 18952, and 18961 and randomly assigned during the period of 1984 to 2005. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% CIs for women compared with men, adjusted for age, Breslow thickness, body site, ulceration, performed lymph node dissection, and treatment. RESULTS: A total of 2,672 patients with stage I/II melanoma were included. Women had a highly consistent and independent advantage in overall survival (adjusted HR, 0.70; 95% CI, 0.59 to 0.83), disease-specific survival (adjusted HR, 0.74; 95% CI, 0.62 to 0.88), time to lymph node metastasis (adjusted HR, 0.70; 95% CI, 0.51 to 0.96), and time to distant metastasis (adjusted HR, 0.69; 95% CI, 0.59 to 0.81). Subgroup analysis showed that the female advantage was consistent across all prognostic subgroups (with the possible exception of head and neck melanomas) and in pre- and postmenopausal age groups. CONCLUSION: Women have a consistent and independent relative advantage in all aspects of the progression of localized melanoma of approximately 30%, most likely caused by an underlying biologic sex difference.