784 resultados para 899


Relevância:

10.00% 10.00%

Publicador:

Resumo:

meso-Tetra (alpha, alpha, alpha, alpha-O-phenylacetyl benzene) porphyrin was used as a complete antigen to elicit monoclonal antibody 1F2 through the immunization and cell fusion techniques. McAb 1F2 obtained was demonstrated very pure by HPLC and MALDI/TOFMS. The retention time of McAb 1F2 was 2. 63 min. The subtype of McAb 1F2 was IgG2a. The relative molecular weight was 156 678. 8. When the McAb 1F2-porphyrin was formed, the maximal absorption of the porphyrin soret region had a redshift from 408 to 416 nm and hyperchromical effect, showing that the antigen-antibody combination was rigid and intense, and the abzyme constancy was high. But compared with HRP, the activity of the abzyme was only 4. 687 5 U/mg and 1. 899 % of that of HRP. Its K-m was 20. 29 mmol/L, k(cat) 396. 82 min(-1), k(cat)/K-m. 1. 955 7 X 10(4) L . mol(-1) . min(-1).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Square-wave voltommetry is used to study the oxidation of polypyrrole doped with dodecylsulfate. The net current curve in this experiment shows why the oxidation current does not display the capacitive-like shape common in cyclic voltammetry. In cyclic voltammetry, the redox behavior of polypyrrole is attributed to the size of dodecylsulfate, irreversible incorporation and the complete consumption of dodecylsulfate. After the polypyrrole film was scanned in aqueous NaCl solution, square wave voltammetric measurements show different results, indicating the change of the polymer nature with regard to the charge transport. This is explained by anion replacement, exclusion and the change of the charge transport mechanism.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Rare earth complexes of m-nitrobenzoic acid (LnL3.2H2O, Ln = La-Lu and Y, except Pm, HL = m-nitrobenzoic acid) were synthesized and characterized by elemental analysis, chemical analysis, IR spectroscopy and X-ray diffraction analysis. The dehydration beh

Relevância:

10.00% 10.00%

Publicador:

Resumo:

New copolyether sulfones containing 2,5-bis(4-oxo-benzylidene)-cyclopentanone moieties were prepared in the conventional literature manner by condensing the dipotassium salts of 2,5-bis(4-hydroxybenzylidene)cyclopentanone (I) and 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A, III) with 4,4'-dichlorodiphenyl sulfone (II), or by condensing the dipotassium salts of I with chlorine-terminated Bisphenol A-4,4'-dichlorodiphenylsulfone copolymers (V). The resulting copolyether sulfones were confirmed by IR, viscometry, DSC measurements, thermooptical analysis (TOA), and thermogravimetric analysis (TGA).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

在自然生长状态下 ,用测定在黄头鹡鸰(Motacillacitreola)成鸟产卵期性腺及输卵管蛋的质量变化的方法 ,研究了它们在产卵期间的能量投入及其分配形式 .产卵期 ,雌鸟用于性腺增长和卵形成的能量预算为 6 6 2 4~71 19kJ ,其中用于蛋白质和脂肪的能量分别为 40 42kJ和 2 5 82~ 30 78kJ,占总能量预算的 5 6 8%~ 6 1 0 %和36 3%~ 46 5 % .用于繁殖蛋白的能量分配为 :输卵管 2 77kJ ,卵黄蛋白 12 80kJ ,卵白蛋白 2 4 85kJ.雌鸟耗能最大的是第 0d~ +1d ,达 (13 2 8~ 14 2 6 )kJ/d .产卵期雄鸟耗能 (用于性腺增长 ) 7 98kJ,雌雄亲鸟用于卵的形成和性腺增长共投入能量 74 2 2~ 79 17kJ.雌鸟耗能为雄鸟的 8 3倍~ 8 9倍。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

镁铁岩-超镁铁岩侵人体中常常含有少量及微量硫化物,它们是硅酸盐岩浆与硫化物熔体不混溶作用的产物。由于岩石圈环境下铂族元素亲硫性的制约,当硅酸盐岩浆与硫化物熔体呈液态熔离时,铂族元素便被硫化物熔体所捕集和运载,尔后在重力分异过程中下沉到岩盆底部富集成矿。能否依据岩盆上部岩浆熔离硫化物的铂族元素丰度值来判断岩盆深部铂族元素潜在成矿能力呢?这是本文试图回答的问题.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Internet and World Wide Web have had, and continue to have, an incredible impact on our civilization. These technologies have radically influenced the way that society is organised and the manner in which people around the world communicate and interact. The structure and function of individual, social, organisational, economic and political life begin to resemble the digital network architectures upon which they are increasingly reliant. It is increasingly difficult to imagine how our ‘offline’ world would look or function without the ‘online’ world; it is becoming less meaningful to distinguish between the ‘actual’ and the ‘virtual’. Thus, the major architectural project of the twenty-first century is to “imagine, build, and enhance an interactive and ever changing cyberspace” (Lévy, 1997, p. 10). Virtual worlds are at the forefront of this evolving digital landscape. Virtual worlds have “critical implications for business, education, social sciences, and our society at large” (Messinger et al., 2009, p. 204). This study focuses on the possibilities of virtual worlds in terms of communication, collaboration, innovation and creativity. The concept of knowledge creation is at the core of this research. The study shows that scholars increasingly recognise that knowledge creation, as a socially enacted process, goes to the very heart of innovation. However, efforts to build upon these insights have struggled to escape the influence of the information processing paradigm of old and have failed to move beyond the persistent but problematic conceptualisation of knowledge creation in terms of tacit and explicit knowledge. Based on these insights, the study leverages extant research to develop the conceptual apparatus necessary to carry out an investigation of innovation and knowledge creation in virtual worlds. The study derives and articulates a set of definitions (of virtual worlds, innovation, knowledge and knowledge creation) to guide research. The study also leverages a number of extant theories in order to develop a preliminary framework to model knowledge creation in virtual worlds. Using a combination of participant observation and six case studies of innovative educational projects in Second Life, the study yields a range of insights into the process of knowledge creation in virtual worlds and into the factors that affect it. The study’s contributions to theory are expressed as a series of propositions and findings and are represented as a revised and empirically grounded theoretical framework of knowledge creation in virtual worlds. These findings highlight the importance of prior related knowledge and intrinsic motivation in terms of shaping and stimulating knowledge creation in virtual worlds. At the same time, they highlight the importance of meta-knowledge (knowledge about knowledge) in terms of guiding the knowledge creation process whilst revealing the diversity of behavioural approaches actually used to create knowledge in virtual worlds and. This theoretical framework is itself one of the chief contributions of the study and the analysis explores how it can be used to guide further research in virtual worlds and on knowledge creation. The study’s contributions to practice are presented as actionable guide to simulate knowledge creation in virtual worlds. This guide utilises a theoretically based classification of four knowledge-creator archetypes (the sage, the lore master, the artisan, and the apprentice) and derives an actionable set of behavioural prescriptions for each archetype. The study concludes with a discussion of the study’s implications in terms of future research.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: Seniors age 65 and older represent the fastest-growing sector of the population and, like many Americans, are increasingly drawn to yoga. This presents both an extraordinary opportunity and a serious challenge for yoga instructors who must be both a resource and guardians of safety for this uniquely vulnerable group. A typical class of seniors is likely to represent the most diverse mix of abilities of any age group. While some may be exceedingly healthy, most fit the profile of the average older adult in America, 80% of whom have at least one chronic health condition and 50% of whom have at least two. OBJECTIVES: This article discusses the Therapeutic Yoga for Seniors program, offered since 2007 at Duke Integrative Medicine to fill a critical need to help yoga instructors work safely and effectively with the increasing number of older adults coming to yoga classes, and explores three areas that pose the greatest risk of compromise to older adult students: sedentary lifestyle, cardiovascular disease, and osteoporosis. To provide a skillful framework for teaching yoga to seniors, we have developed specific Principles of Practice that integrate the knowledge gained from Western medicine with yogic teachings.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: Most information about the lifetime prevalence of mental disorders comes from retrospective surveys, but how much these surveys have undercounted due to recall failure is unknown. We compared results from a prospective study with those from retrospective studies. METHOD: The representative 1972-1973 Dunedin New Zealand birth cohort (n=1037) was followed to age 32 years with 96% retention, and compared to the national New Zealand Mental Health Survey (NZMHS) and two US National Comorbidity Surveys (NCS and NCS-R). Measures were research diagnoses of anxiety, depression, alcohol dependence and cannabis dependence from ages 18 to 32 years. RESULTS: The prevalence of lifetime disorder to age 32 was approximately doubled in prospective as compared to retrospective data for all four disorder types. Moreover, across disorders, prospective measurement yielded a mean past-year-to-lifetime ratio of 38% whereas retrospective measurement yielded higher mean past-year-to-lifetime ratios of 57% (NZMHS, NCS-R) and 65% (NCS). CONCLUSIONS: Prospective longitudinal studies complement retrospective surveys by providing unique information about lifetime prevalence. The experience of at least one episode of DSM-defined disorder during a lifetime may be far more common in the population than previously thought. Research should ask what this means for etiological theory, construct validity of the DSM approach, public perception of stigma, estimates of the burden of disease and public health policy.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In the United States, poverty has been historically higher and disproportionately concentrated in the American South. Despite this fact, much of the conventional poverty literature in the United States has focused on urban poverty in cities, particularly in the Northeast and Midwest. Relatively less American poverty research has focused on the enduring economic distress in the South, which Wimberley (2008:899) calls “a neglected regional crisis of historic and contemporary urgency.” Accordingly, this dissertation contributes to the inequality literature by focusing much needed attention on poverty in the South.

Each empirical chapter focuses on a different aspect of poverty in the South. Chapter 2 examines why poverty is higher in the South relative to the Non-South. Chapter 3 focuses on poverty predictors within the South and whether there are differences in the sub-regions of the Deep South and Peripheral South. These two chapters compare the roles of family demography, economic structure, racial/ethnic composition and heterogeneity, and power resources in shaping poverty. Chapter 4 examines whether poverty in the South has been shaped by historical racial regimes.

The Luxembourg Income Study (LIS) United States datasets (2000, 2004, 2007, 2010, and 2013) (derived from the U.S. Census Current Population Survey (CPS) Annual Social and Economic Supplement) provide all the individual-level data for this study. The LIS sample of 745,135 individuals is nested in rich economic, political, and racial state-level data compiled from multiple sources (e.g. U.S. Census Bureau, U.S. Department of Agriculture, University of Kentucky Center for Poverty Research, etc.). Analyses involve a combination of techniques including linear probability regression models to predict poverty and binary decomposition of poverty differences.

Chapter 2 results suggest that power resources, followed by economic structure, are most important in explaining the higher poverty in the South. This underscores the salience of political and economic contexts in shaping poverty across place. Chapter 3 results indicate that individual-level economic factors are the largest predictors of poverty within the South, and even more so in the Deep South. Moreover, divergent results between the South, Deep South, and Peripheral South illustrate how the impact of poverty predictors can vary in different contexts. Chapter 4 results show significant bivariate associations between historical race regimes and poverty among Southern states, although regression models fail to yield significant effects. Conversely, historical race regimes do have a small, but significant effect in explaining the Black-White poverty gap. Results also suggest that employment and education are key to understanding poverty among Blacks and the Black-White poverty gap. Collectively, these chapters underscore why place is so important for understanding poverty and inequality. They also illustrate the salience of micro and macro characteristics of place for helping create, maintain, and reproduce systems of inequality across place.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El consumo de productos naturales en el mundo es cada vez más creciente, y dentro de ello las bebidas funcionales que desde sus orígenes han tenido una performance relativamente satisfactoria. El yacón (Smallanthus sochifolius)es una planta perene, herbácea, que crece en toda la serranía peruana. Su demanda en el mercado exterior ha hecho que cada vez tenga mayor importancia. En el 2014 se exportó USD 2 899.398,00 en forma de polvo, jarabe, deshidratado; sin embargo su consumo en el mercado nacional es bajo, a pesar del gran potencial nutritivo que posee. El mercado de Lima moderna se presenta como un importante atractivo de mercado que podría consumir la bebida. Por ello el objetivo del presente trabajo es Realizar un Plan de Marketing para el mercado de Lima moderna a fin de evaluar la factibilidad de insertar una bebida nueva: yacón con piña, para fomentar el consumo interno de este producto. La metodología utilizada fue de carácter exploratorio, descriptivo cuantitativa y cualitativa mediante información primaria y secundaria que ayudó a su desarrollo. Dentro de la información primaria se utilizó como herramienta la encuesta y la información secundaria a través de informes y estudios que se hicieron para el sector de bebidas no alcohólicas. El sector de bebidas no alcohólicas en el Perú, muestra un importante crecimiento en lo referente a bebidas saludables. En el último año (2014) el crecimiento de este sector fue de 6 por ciento, motivados por la percepción del consumidor en los beneficios saludables de estas bebidas. La zona de Lima moderna acoge al 72,2 por ciento del nivel socio económico A y B, este segmento concentra el más alto promedio de ingresos. En el análisis de Porter, se describe a la empresa como una industria, el cual para este rubro las barreras de ingreso son altas por la inversión en activos físicos y la inversión en publicidad y promoción por ser un producto nuevo. A través del estudio realizado se encontró que existe demanda para este producto, el 31,1 por ciento de los encuestados compraría definitivamente, 25,5 por ciento una vez por semana y el 18,3 por ciento todos los días. La estrategia utilizada en el presente trabajo fue la diferenciación, por las características saludables de la bebida y única en el mercado. La bebida es un producto de introducción en el mercado, el precio fijado es alto porque se orienta a un segmento de mercado selectivo y además fijado en la imagen y calidad del producto. La distribución se realizará a través de los supermercados, minimarkets, hoteles categorizados. Y por último se concluye que la introducción de un producto novedoso, podría marcar estándares en el mercado de bebidas no alcohólicas y permitir la creación de una nueva categoría de productos Premium naturales y funcionales.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Se aborda, desde una perspectiva socioepistemológica, la construcción del conocimiento y el desarrollo del pensamiento proporcional buscando generar espacios de reflexión y de interacción con el profesorado y el estudiantado que posibiliten la resignificación del conocimiento institucionalizado. Recurre entre otras fuentes y técnicas, al análisis de textos didácticos clásicos y contemporáneos, con el objeto de visualizar la naturaleza y evolución de los saberes matemáticos y escolares en juego, y, decidir aspectos necesarios a los diseños de secuencias didácticas en orden a favorecer la significación de fracciones, razones y proporciones como conceptos-herramientas en el estudiantado en el ámbito de la proporcionalidad. Tiene el objetivo de comprender de qué manera las prácticas que toman lugar en el aula, contribuyen al desarrollo del pensamiento proporcional de los estudiantes, en los niveles 5º al 10º de la escolaridad obligatoria.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This is a report of two lectures held by the London Mathematical Society: a) What Computers Cannot Do by Dr Alan Slomson; b) The Mathematics of Shrek by Dr Joan Lazenby.