998 resultados para ~(233)Pa
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用233Pa作示踪剂,苯作稀释剂,研究了二异丙酮(Di-iso-propyl-ketone)对Pa的溶剂萃取行为。分析了萃取效率与震荡时间、不同种类的无机酸浓度和萃取剂浓度的关系及F-对Pa溶剂萃取的影响。结果表明,二异丙酮是萃取Pa的一种优良的萃取剂;二异丙酮-盐酸体系适用于Pa的萃取研究。
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用~(233)Pa做示踪剂,分别使用ABS树脂、有机玻璃、聚乙烯和普通玻璃试管做吸附材料,研究了在不同浓度的HCL溶液中~(233)Pa在试管壁上的吸附。结果显示,~(233)Pa在试管壁上的吸附随盐酸浓度的增加而减少。当HCL浓度≥0.5mol/L时,同ABS树脂和有机玻璃比较,~(233)Pa在玻璃试管壁上的吸附最少。当HCL浓度≤0.25mol/L时,~(233)Pa在玻璃试管壁上的吸附反而比在ABS树脂和有机玻璃试管壁上的大。若~(233)Pa的HCL溶液在聚乙烯、ABS树脂和玻璃试管中存放较长的时间(24h),聚乙烯试管壁对~(233)Pa的吸附量最少。
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The extraction of protactinium with Aliquat 336 (methyl-tri-caprylyl ammonium chloride) in toluene, cyclohexane and chloroform from HCl, HNO3, H2SO4, HClO4, HF and mixed HCl-HF media was investigated by radioactive tracer technique. Distribution ratios of protactinium between the aqueous solution and the organic phase were determined as a function of shaking time, concentrations of acid in aqueous solution phase, extractant concentration and type of diluents in the organic phase. Aliquat 336 can almost quantitatively extract protactinium from strong HCl solution. At the same time, small amounts of HF in HCl solutions have a strong effect on Pa distribution.
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The estimation method of the universe age using the nuclear cosmochronology by the heavy chronometers is essentialized. The influence of the novel long half-life of Pa-239 on the universe age estimation is simply mentioned.
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Objective The Active Australia Survey (AAS) is used for physical activity (PA) surveillance in the general Australian adult population, but its validity in older adults has not been evaluated. Our aim was to examine the convergent validity of the AAS questions in older adults. Design The AAS was validated against pedometer step counts as an objective measure of PA, self-reported physical function, and a step-test to assess cardiorespiratory fitness. Method Participants were community-dwelling adults, aged 65-89 y, with the ability to walk 100 m. They completed a self-administered AAS and the step-test in one interview. One week earlier, they completed the Short Form-36 physical function subscale. Between these two interviews, they each wore a YAMAX Digiwalker SW200 pedometer and recorded daily steps. Using the AAS data, daily walking minutes and total PA minutes (walking, moderate-intensity PA and vigorous-intensity PA) were compared with the validity measures using Spearman rank-order correlations. Fifty-three adults completed the study. Results Median daily walking minutes were 34.2 (interquartile range [IQR] 17.1, 60.0), and median daily total PA minutes were 68.6 (IQR 31.4, 113.6). Walking and total PA minutes were both moderately correlated with pedometer steps (Spearman correlation r=0.42, p=0.003, for each) but not with step-test seconds to completion (r=-0.11, p=0.44; r=-0.25, p=0.08, respectively). Total PA minutes were significantly correlated with physical function scores (r=0.39, p=0.004), but walking minutes were not (r=0.15, p=0.29). Conclusions This initial examination of the psychometric properties of the AAS for older adults suggests that this surveillance tool has acceptable convergent validity for ambulatory, community-dwelling older adults.
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The impact of Web 2.0 and social networking tools such as virtual communities, on education has been much commented on. The challenge for teachers is to embrace these new social networking tools and apply them to new educational contexts. The increasingly digitally-abled student cohorts and the need for educational applications of Web 2.0 are challenges that overwhelm many educators. This chapter will make three important contributions. Firstly it will explore the characteristics and behaviours of digitally-abled students enrolled in higher education. An innovation of this chapter will be the appli- cation of Bourdieu’s notions of capital, particularly social, cultural and digital capital to understand these characteristics. Secondly, it will present a possible use of a commonly used virtual community, Facebook©. Finally it will offer some advice for educators who are interested in using popular social networking communities, similar to Facebook©, in their teaching and learning.
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Background: The regulation of plasminogen activation is a key element in controlling proteolytic events in the extracellular matrix. Our previous studies had demonstrated that in inflamed gingival tissues, tissue-type plasminogen activator (t-PA) is significantly increased in the extracellular matrix of the connective tissue and that interleukin 1β (IL-1β) can up regulate the level of t-PA and plasminogen activator inhibitor-2 (PAI-2) synthesis by human gingival fibroblasts. Method: In the present study, the levels of t-PA and PAI-2 in gingival crevicular fluid (GCF) were measured from healthy, gingivitis and periodontitis sites and compared before and after periodontal treatment. Crevicular fluid from106 periodontal sites in 33 patients were collected. 24 sites from 11 periodontitis patients received periodontal treatment after the first sample collection and post-treatment samples were collected 14 days after treatment. All samples were analyzed by enzyme-linked immunosorbent assay (ELISA) for t-PA and PAI-2. Results: The results showed that significantly high levels of t-PA and PAI-2 in GCF were found in the gingivitis and periodontitis sites. Periodontal treatment led to significant decreases of PAI-2, but not t-PA, after 14 days. A significant positive linear correlation was found between t-PA and PAI-2 in GCF (r=0.80, p<0.01). In the healthy group, different sites from within the same subject showed little variation of t-PA and PAI-2 in GCF. However, the gingivitis and periodontitis sites showed large variation. These results suggest a good correlation between t-PA and PAI-2 with the severity of periodontal conditions. Conclusion: This study indicates that t-PA and PAI-2 may play a significant rôle in the periodontal tissue destruction and tissue remodeling and that t-PA and PAI-2 in GCF may be used as clinical markers to evaluate the periodontal diseases and assess treatment.
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OBJECTIVE Interest is growing in promoting utility cycling (i.e., for transport) as a means of incorporating daily physical activity (PA) into people’s lives, but little is known about correlates of utility cycling. Our primary aim was to examine cross-sectional relationships between socio-economic characteristics, neighborhood environment perceptions and psychological disposition with utility cycling (with or without additional recreational cycling). A secondary aim was to compare these relationships with those for recreation-only cycling. METHOD Baseline survey data (2007) from 10,233 participants in HABITAT, a multilevel longitudinal study of PA, sedentary behavior, and health in Brisbane adults aged 40-65 years, were analysed using multinomial regression modelling. RESULTS Greater income, habitual PA, and positive beliefs about PA were associated with utility and recreation-only cycling (p<0.05). Always having vehicle access and not in the labor force were associated with recreation-only cycling (p<0.05). Some or no vehicle access, part-time employment, and perceived environmental factors (little crime, few cul-de-sacs, nearby transport and recreational destinations) were associated with utility cycling (p<0.05). CONCLUSION Our findings suggest differences in associations between socio-economic, neighborhood perceptions and psychological factors and utility and recreation-only cycling in Brisbane residents aged 40-65 years. Tailored approaches appear to be required to promote utility and recreational cycling.
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PURPOSE
The purposes of this study were to:
1) establish inter-instrument reliability between left and right hip accelerometer placement;
2) examine procedural reliability of a walking protocol used to measure physical activity (PA), and;
3) confirm concurrent validity of accelerometers in measuring PA intensity as compared to the gold standard of oxygen consumption measured by indirect calorimetry.
METHODS
Eight children (mean age: 11.9; SD: 3.2, 75% male) with CP (GMFCS levels I-III) wore ActiGraph GT3X accelerometers on each hip and the Cosmed K4b
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We investigate the use of a two stage transform vector quantizer (TSTVQ) for coding of line spectral frequency (LSF) parameters in wideband speech coding. The first stage quantizer of TSTVQ, provides better matching of source distribution and the second stage quantizer provides additional coding gain through using an individual cluster specific decorrelating transform and variance normalization. Further coding gain is shown to be achieved by exploiting the slow time-varying nature of speech spectra and thus using inter-frame cluster continuity (ICC) property in the first stage of TSTVQ method. The proposed method saves 3-4 bits and reduces the computational complexity by 58-66%, compared to the traditional split vector quantizer (SVQ), but at the expense of 1.5-2.5 times of memory.
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In this paper, we report drain-extended MOS device design guidelines for the RF power amplifier (RF PA) applications. A complete RF PA circuit in a 28-nm CMOS technology node with the matching and biasing network is used as a test vehicle to validate the RF performance improvement by a systematic device design. A complete RF PA with 0.16-W/mm power density is reported experimentally. By simultaneous improvement of device-circuit performance, 45% improvement in the circuit RF power gain, 25% improvement in the power-added efficiency at 1-GHz frequency, and 5x improvement in the electrostatic discharge robustness are reported experimentally.
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Consultoria Legislativa - Área III - Tributação e Direito Tributário.
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Reunião dos Ministros com o Presidente José Sarney discute a posição do governo sobre o sistema de governo. O Ministro da Casa Civil Ronaldo Couto declara que o governo está aberto ao diálogo mas que os ministros trabalharão a favor do presidencialismo. Constituintes opinam sobre a influência do governo na Assembleia Nacional Constituinte (ANC). O Deputado Vingt Rosado (PMDB-RN) opina sobre a interferência do Presidente. O Deputado Enoc Vieira (PFL-MA) declara que o Presidente tem o direito de opinar e que os constituintes têm o direito de discordar. O Relator Bernardo Cabral reúne com empresários e os sindicalistas da Central Única dos Trabalhadores (CUT) e da Confederação Geral dos Trabalhadores (CGT) para discutir uma ampla pauta, na qual se destacou a jornada de quarenta horas. Joaquim dos Santos, presidente da CGT, declara que os empresários querem que tudo seja regulamentado por leis ordinárias. O Senador Albano Franco (PSDB-SE), representante dos empresários, afirma que nenhum país no mundo tem a jornada de trabalho definida no texto da Constituição. Jair Meneghelli, presidente da CUT, esclarece que não houve nenhum acordo e espera uma decisão justa do Relator, que contemple o conjunto da classe trabalhadora. O Deputado Bernardo Cabral reuniu-se também com um grupo de constituintes progressistas, que queriam saber sobre o tratamento que seria dado a questões como a censura e a reforma agrária. O Deputado Haroldo Lima (PC do B-BA) informa que o Relator demonstrou uma atitude aberta para essas questões, mas não anunciou nenhuma opinião conclusiva. O Partido da Frente Liberal (PFL) também fez reunião com Bernardo Cabral. Marco Maciel (PFL-PE) afirma que, sem conversa, não se conseguirá produzir um texto duradouro em relação a diversos temas, como é o caso do sistema de governo. Constituintes de diversos partidos fecharam acordo para a aprovação do parlamentarismo e a proposta foi entregue ao Presidente da Assembleia Nacional Constituinte (ANC), Deputado Ulysses Guimarães. O Senador José Richa (PMDB-PR) explica que se chegou a um acordo em favor do parlamentarismo clássico, mas que falta definir como será a duração da transição. O Deputado Euclides Scalco (PMDB-PR) crê em um acordo para o restante dos pontos pendentes.