Investigations of the origin of stereocontrol in syndiospecific Ziegler-Natta polymerizations

In order to expand our understanding of the mechanism of stereocontrol in syndiospecific α-olefin polymerization, a family of Cs-symmetric, ansa-group 3 metallocenes was targeted as polymerization catalysts. The syntheses of new ansa-yttrocene and scandocene derivatives that employ the doubly [SiMe₂]- bridged ligand array (1,2-SiMe₂)₂{C₅H-3,5-(CHMe₂)₂} (where R = t- butyl, tBuThp; where R = i-propyl, iPrThp) are described. The structures of tBuThpY(µ-Cl)₂K(THF)₂, tBuThpSc(µ-Cl)₂K(Et₂O)₂, tBuThpYCH(SiMe₃)₂, Y₂{µ₂-(tBuThp)₂}(µ₂-H)₂, and tBuThpSc(µ-CH₃)₂ have been examined by single crystal X-ray diffraction methods. Ansa-yttrocenes and scandocenes that incorporate the singly [CPh₂]-bridged ligand array (CPh₂)(C₅H₄)(C₁₃H₈)(where C₅H₄ = Cp, cyclopentadienyl; where C₁₃H₈ = Flu, fluourenyl) have also been prepared. Select meallocene alkyl complexes are active single component catalysts for homopolymerization of propylene and 1-pentene. The scandocene tetramethylaluminate complexes generate polymers with the highes molecular weights of the series. Under all conditions examined atactic polymer microstructures are observed, suggesting a chain-end mechanism for stereocontrol.

A series of ansa-tantalocenes have been prepared as models for Ziegler-Natta polymerization catalysts. A singly bridged ansa-tantalocene trimethyl complex, Me₂Si(η⁵-C₅H₄)₂TaMe₃, has been prepared and used for the synthesis of a tantalocene ethylene-methyl complex. Addition of propylene to this ethylene-methyl adduct results in olefin exchange to give a mixture of endo and exo propylene isomers. Doubly-silylene bridged ansa-tantalocene complexes have been prepared with the tBuThp ligand; a tantalocene trimethyl complex and a tantalocene methylidene-methyl complex have been synthesized and characterized by X-ray diffraction. Thermolysis of the methylidene-methyl complex affords the corresponding ethylene-hydride complex. Addition of either propylene or styrene to this ethylene-hydride compound results in olefin exchange. In both cases, only one product isomer is observed. Studies of olefin exchange with ansa-tantalocene olefin-hydride and olefin-methyl complexes have provided information about the important steric influences for olefin coordination in Ziegler-Natta polymerization.

Intercepting beats in predesignated target zones

Moving to a rhythm necessitates precise timing between the movement of the chosen limb and the timing imposed by the beats. However, the temporal information specifying the moment when a beat will sound (the moment onto which one must synchronise one's movement) is not continuously provided by the acoustic array. Because of this informational void, the actors need some form of prospective information that will allow them to act sufficiently ahead of time in order to get their hand in the right place at the right time. In this acoustic interception study, where participants were asked to move between two targets in such a way that they arrived and stopped in the target zone at the same time as a beat sounded, we tested a model derived from tau-coupling theory (Lee DN (1998) Ecol Psychol 10:221-250). This model attempts to explain the form of a potential timing guide that specifies the duration of the inter-beat intervals and also describes how this informational guide can be used in the timing and guidance of movements. The results of our first experiment show that, for inter-beat intervals of less than 3 s, a large proportion of the movement (over 70%) can be explained by the proposed model. However, a second experiment, which augments the time between beats so that it surpasses 3 s, shows a marked decline in the percentage of information/movement coupling. A close analysis of the movement kinematics indicates a lack of control and anticipation in the participants' movements. The implications of these findings, in light of other research studies, are discussed.

Adulteration and Poor Quality of Ginkgo biloba Supplements

Adulteration of Ginkgo products sold as unregistered supplements within the very large market of Ginkgo products (reputedly £650 million annually) through the post-extraction addition of cheaper (e.g. buckwheat derived) rutin is suspected to allow sub-standard products to appear satisfactory to third parties, e.g. secondary buyers along the value chain or any regulatory authorities. This study was therefore carried out to identify products that did not conform to their label specification and may have been actively adulterated to enable access to the global markets. 500 MHz Bruker NMR spectroscopy instrumentation combined with Topspin version 3.2 and a CAMAG HPTLC system (HPTLC Association for the analysis of Ginkgo biloba leaf) were used to generate NMR spectra (focusing on the 6–8 ppm region for analysis) and chromatograms, respectively. Out of the 35 samples of Ginkgo biloba analysed, 33 were found to contain elevated levels of rutin and/or quercetin, or low levels of Ginkgo metabolites when compared with the reference samples. Samples with disproportional levels of rutin or quercetin compared with other gingko metabolites are likely to be adulterated, either by accident or intentionally, and those samples with low or non-existent gingko metabolite content may have been produced using poor extraction techniques. Only two of the investigated samples were found to match with the High-Performance Thin-Layer Chromatography (HPTLC) fingerprint of the selected reference material. All others deviated significantly. One product contained a 5-hydroxytryptophan derivative, which is not a natural constituent of Ginkgo biloba. Overall, these examples either suggest a poor extraction technique or deliberate adulteration along the value chain. Investigating the ratio of different flavonoids e.g. quercetin and kaempferol using NMR spectroscopy and HPTLC will provide further evidence as to the degree and kind of adulteration of Gingko supplements. From a consumer perspective the equivalence in identity and overall quality of the products needs to be guaranteed for supplements too and not only for products produced according to a quality standard or pharmacopoeial monograph.

Citotoxicidade do ácido peracético: avaliação metabólica, estrutural e de morte em fibroblastos L929

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Será do género dos filhos ou dos pais? estudo sobre o efeito do género das crianças e dos pais na qualidade da interação, comunicação e atividade conjunta

Dissertação apresentada na Escola Superior de Educação de Lisboa para obtenção do grau de Mestre em Ciências da Educação. Especialidade Intervenção Precoce

Righteous sounds and reproductive justice : the influence of Ani DiFranco's music for reproductive rights activists

In this thesis, I explore how the folk-rock music of Ani DiFranco has influenced the activist commitments, sensibilities, and activities of reproductive rights activists. My interest in the relation of popular music to social movements is informed by the work of Simon Frith (1987, 1996a, 1996b), Rob Rosenthal (2001), and Ann Savage (2003). Frith argues that popular music is an important contributor to personal identity and the ways that listeners see the world. Savage (2003) writes that fans develop a unique relationship with feminist/political music, and Rosenthal (2001) argues that popular music can be an important factor in building social movements. I use these arguments to ask what the influence of Ani DiFranco's music has been for reproductive rights activists who are her fans. I conducted in-depth interviews with ten reproductive rights activists who are fans of Ani DiFranco's music. All ten are women in their twenties and thirties living in Ontario or New York. Each has been listening to DiFranco's music for between two and fifteen years, and has considered herself a reproductive rights activist for between eighteen months and twenty years. I examine these women's narratives of their relationships with Ani DiFranco's music and their activist experience through the interconnected lenses of identity, consciousness, and practice. Listening to Ani DiFranco's music affects the fluid ways these women understand their identities as women, as feminists, and in solidarity with others. I draw on Freire's (1970) understanding of conscientization to consider the role that Ani's music has played in heightening women's awareness about reproductive rights issues. The feeling of solidarity with other (both real and perceived) activist fans gives them more confidence that they can make a difference in overcoming social injustice. They believe that Ani's music encourages productive anger, which in turn fuels their passion to take action to make change. Women use Ani's music deliberately for energy and encouragement in their continued activism, and find that it continues to resonate with their evolving identities as women, feminists, and activists. My study builds on those of Rosenthal (2001) and Savage (2003) by focusing on one artist and activists in one social movement. The characteristics of Ani DiFranco, her fan base, and the reproductive rights movement allow new understanding of the ways that female fans who are members of a female-dominated feminist movement interact with the music of a popular independent female artist.

An aryne route to aporphine alkaloids and related topics / |nIjaz Ahmad Chanda. -- 260 St. Catharines, Ont. : [s. n.],

This research was directed towards the investigation and development of an aryne route to the syntheses of aporphi ne and dibenzopyrrocolinium (dibenzoindolizinium) alkaloids and to the stability of the latter under the conditions used for aryne formation. The work c an be divided into three main sections . i) - Synthesis of Glaucine 6-Bromo-3,4-dimethoxyphenylacetic acid, prepared by the action of bromine i n acetic acid on3,4-dimethoxyphenylacetic a cid, was converted into its acid chloride by t he action of thionyl chloride. This on treatment with 3,4- dimethoxyphenylethylamine pr ovided N-(3, 4-dimethoxyphenylethyl)- 2-(2-bromo-4,S-dimethoxyphenyl)-acetamide which on dehydration with phosphoryl chloride (Bischler Napieralski reaction) in dry benzene afforded l -(2-bromo-4,S-dimethoxybenzyl)- 3,4-dihydro-6,7-dimethoxyisoquinoline, isolated as hydrochl oride. A new method o f destroying the excess of phosphoryl chloride was developed which proved to be quite useful. Methylation of the dihydroisoquinoline'with methyl iodide in methanol , and subsequent reduction with sodium borohydride provided (±)-6-bromolaudanosine. Act ion of potassamide or sodamide in anhydrous liquid ammonia on (±)-6-bromolaudanosine yielded the corresponding amino derivative along with other products. Diazotization and ring closure of (±)-6-aminolaudanosine then a f forded (±)-glaucine which was isolated as methiodide. ii) - Intramolecular Capture of Aryne During Glaucine Synthesis, and Subsequent Reactions . This section deals with the by-products formed under the conditions of the aryne stage of t he glaucine synthesis. The crude product, obtained in the reaction of potassamide or sodamide in liquid ammonia on (±)-6-bromolaudanosine, was s eparated by chromatography, Three products were separated and identified. a ) - 5,6-Dimethoxy-2-( 3,4-dimethoxy-6-ethylphenyl)-lmethylindole. Two mechanisms are proposed for the formation of this interesting product. This compound also was prepared by the action of potassamide in l,iquid ammonia on 5,6 ,l2,l2atetrahydro- 2,3,9,lO-tetramethoxy-7-methyldibenz[b,g]indolizinium i odide . b) - 5,6-Dimethoxy-2-(3,4-dimethoxy-6-vinylphenyl)-lmethylindoline. Its formation represented a new method of Hofmann degradation . Further confirmation of structure was done by performing the normal Hofmann reaction on 5, 6,12,12a-tetrahydro -2/3,9,lO-tetramethoxy ~7-methyldibe nz[ b,g]indolizinium iodide. The indoline prepared i n this way was identical in all respects with that prepared above . c) - 1- (2-amino-4,5-dimethoxybenzyl ) -l,2,3,4-tetrahydro-2- methyl-6,7-dimethoxyisoquinoline, was converted t o glaucine as stated in section 1 . iii) - Attempt:,ed Sxnthesis of Liriodenine Piperonal was converted into 3,4-methylenedioxyinitrostyrene which on reduction with lithium aluminium hydride provided 3,4-methylenedioxyphenylethylamine. The method of extraction after the reduction was improved t o some extent. The amine on condensation with m-chlorophenylacetyl chloride, prepared by the action of oxalyl chloride on 3,4-methylenedioxyphenylacetic acid, provided N-[ ~ -(3,4-methylenedioxyphenyl)- e thyl)-3-chlorophenylacetamide. This on dehydration with phosphoryl chloride in dry benzene followed by air oxidation afforded l-(3-chlorobenzoyl)-6,7-methylenedioxyi soquinoline. This compound on r eaction with potassamide in liquid ammonia afforded a crude product from which. one product was separated by chromatography i n a pure condition . This yellow compound analysed as,c17Hl ON2021 and was t he main product i n the reaction ; a t entative structure is proposed. A second compound, not obtained in pure condition, was submitted to Pschorr reaction in the hope of obtaining liriodenine, but without success.

Understanding Network Governance: A Case Study Exploration of Active Canada 20/20

Consistent with the governance shift towards network forms of governance, a number of new social movements have formed in response to the declining levels of physical activity in the Western world. One such movement is Active Canada 20/20: A Physical Activity Strategy and Change Agenda for Canada. Network governance is employed as the theoretical framework for this case study exploration of Active Canada 20/20 and the political landscape surrounding its development and implementation. Semi-structured interviews were conducted in addition to document/policy analysis and direct observations. Analysis of the data resulted in three overarching themes – the defining characteristics of network governance, the political landscape, and intersectoral linkages – that interconnect multifariously based the nature of the Canadian federal government and its relationship with the voluntary sector for physical activity. Despite progress in driving Active Canada 20/20 forward, entrenched dynamics of power need to be navigated within the political landscape surrounding network governance.

Computer vision techniques in seafood quality control

The application of computer vision based quality control has been slowly but steadily gaining importance mainly due to its speed in achieving results and also greatly due to its non- destnictive nature of testing. Besides, in food applications it also does not contribute to contamination. However, computer vision applications in quality control needs the application of an appropriate software for image analysis. Eventhough computer vision based quality control has several advantages, its application has limitations as to the type of work to be done, particularly so in the food industries. Selective applications, however, can be highly advantageous and very accurate.Computer vision based image analysis could be used in morphometric measurements of fish with the same accuracy as the existing conventional method. The method is non-destructive and non-contaminating thus providing anadvantage in seafood processing.The images could be stored in archives and retrieved at anytime to carry out morphometric studies for biologists.Computer vision and subsequent image analysis could be used in measurements of various food products to assess uniformity of size. One product namely cutlet and product ingredients namely coating materials such as bread crumbs and rava were selected for the study. Computer vision based image analysis was used in the measurements of length, width and area of cutlets. Also the width of coating materials like bread crumbs was measured.Computer imaging and subsequent image analysis can be very effectively used in quality evaluations of product ingredients in food processing. Measurement of width of coating materials could establish uniformity of particles or the lack of it. The application of image analysis in bacteriological work was also done

Implementación del modelo de negocio en el mercado retail colombiano

La teoría de precios bajos es una estrategia de empresa que se basa en el modelo de eficiencia en costos. Aplicado en diferentes empresas como Walmart, Tesco, Mercadona, entre otras, ha hecho que esta proposición sea aplicada en varias empresas en todo el mundo. Y es necesario saber por qué ha sido una aplicación exitosa en todas estas empresas y la razón de haber tomado la decisión de emplear este modelo. Como es bien sabido, una empresa tiene dos enfoques de estrategia. La primera es la de diferenciación, donde el producto o servicio ofrecido tiene un valor agregado o valor único que hace que su precio no sea relevante, por el contrario, éste demuestra que su oferta en el mercado sea única y como su palabra lo dice, diferenciada a los demás productos. También es necesario entender que la mayoría de estos productos no son bienes comprados por necesidad, sino por el contrario, por gusto y satisfacción personal. Por otro lado, existe la estrategia de liderazgo en costes. Por el contrario de la de diferenciación, los productos a los que se aplica este modelo, se encuentran en mercados de consumo básico y donde la compra se hace de manera inconsciente y rápida. Y es ahí donde las compañías trabajan no para hacerlo único en el mercado, por el contrario, trabajan para hacerlo llamativo, a un precio razonable y donde la calidad ofrecida sea igual o mejor al de la competencia. Es por esto, que la estrategia de costos, busca en todas las maneras posibles abaratar los costos de fabricación, producción y distribución de los productos, de manera que puedan realizar grandes cantidades de ellos, llamadas economías de escala. Es por esto, que uno de los grandes retos para las marcas blancas es competir en calidad y precio frente a grandes marcas reconocidas. Y es ahí donde entra a jugar como factor clave la reducción máxima de costos dentro de las empresas y un manejo excelente en la logística. El proyecto a tratar será sobre este tema de liderazgo en costes y los precios bajos ofrecidos al consumidor como estrategia para abarcar mayor población y de tal manera generar mayores utilidades.

Higher oxides of chlorine: absorption cross-sections of Cl2O6 and Cl2O4, the decomposition of Cl2O6, and the reactions of OClO with O and O-3

The absorption cross-sections of Cl2O6 and Cl2O4 have been obtained using a fast flow reactor with a diode array spectrometer (DAS) detection system. The absorption cross-sections at the wavelengths of maximum absorption (lambda(max)) determined in this study are those of Cl2O6: (1.47 +/- 0.15) x 10(-17) cm(2) molecule(-1), at lambda(max) = 276 nm and T = 298 K; and Cl2O4: (9.0 +/- 2.0) x 10(-19) cm(2) molecule(-1), at lambda(max) = 234 nm and T = 298 K. Errors quoted are two standard deviations together with estimates of the systematic error. The shapes of the absorption spectra were obtained over the wavelength range 200-450 nm for Cl2O6 and 200-350 nm for Cl2O4, and were normalized to the absolute cross-sections obtained at lambda(max) for each oxide, and are presented at 1 nm intervals. These data are discussed in relation to previous measurements. The reaction of O with OCIO has been investigated with the objective of observing transient spectroscopic absorptions. A transient absorption was seen, and the possibility is explored of identifying the species with the elusive sym-ClO3 or ClO4, both of which have been characterized in matrices, but not in the gas-phase. The photolysis of OCIO was also re-examined, with emphasis being placed on the products of reaction. UV absorptions attributable to one of the isomers of the ClO dimer, chloryl chloride (ClClO2) were observed; some Cl2O4 was also found at long photolysis times, when much of the ClClO2 had itself been photolysed. We suggest that reports of Cl2O6 formation in previous studies could be a consequence of a mistaken identification. At low temperatures, the photolysis of OCIO leads to the formation of Cl2O3 as a result of the addition of the ClO primary product to OCIO. ClClO2 also appears to be one product of the reaction between O-3 and OCIO, especially when the reaction occurs under explosive conditions. We studied the kinetics of the non-explosive process using a stopped-flow technique, and suggest a value for the room-temperature rate coefficient of (4.6 +/- 0.9) x 10(-19) cm(3) molecule(-1) s(-1) (limit quoted is 2sigma random errors). The photochemical and thermal decomposition of Cl2O6 is described in this paper. For photolysis at k = 254 nm, the removal of Cl2O6 is not accompanied by the build up of any other strong absorber. The implications of the results are either that the photolysis of Cl2O6 produces Cl-2 directly, or that the initial photofragments are converted rapidly to Cl-2. In the thermal decomposition of Cl2O6, Cl2O4 was shown to be a product of reaction, although not necessarily the major one. The kinetics of decomposition were investigated using the stopped-flow technique. At relatively high [OCIO] present in the system, the decay kinetics obeyed a first-order law, with a limiting first-order rate coefficient of 0.002 s(-1). (C) 2004 Elsevier B.V. All rights reserved.

Identified consumers: an experiment on the informativeness of cross-demand price effects

Often, firms have no information on the specification of the true demand model they are faced with. It is, however, a well established fact that trial-and-error algorithms may be used by them in order to learn how to make optimal decisions. Using experimental methods, we identify a property of the information on past actions which helps the seller of two asymmetric demand substitutes to reach the optimal prices more precisely and faster. The property concerns the possibility of disaggregating changes in each product’s demand into client exit/entry and shift from one product to the other.

Análise comparativa de lojas de departamentos virtuais no Brasil

The present dissertation care is focused on the study of the virtual department stores¿ behavior, through the analysis of following parameters: site design and digital interface with the user, advertising and promotion, logistics, assistance to client, business models, security policies, loyalty programs, payment options and moulds policies. This study will focalizes the department stores which commercializes, on-line, more than one product category produced by third party ¿ so much the ones that chooses the Internet as its only sales channel (e.g.: submarino.com), as much as those that uses Web as a complementary sales channel (e.g.: americanas.com).

Criação de mercado de créditos de biocombustível avançado para geração de economia financeira e ambiental no comércio de etanol entre Brasil e Estados Unidos

O comércio de etanol entre Brasil e Estados Unidos é fortemente guiado por uma assimetria regulatória, que agrega valor ao etanol brasileiro ao gerar uma de-manda americana pelo produto derivado da cana de açúcar. A demanda advém dos mandatos de consumo de biocombustíveis estabelecidos no programa americano conhecido como Renewable Fuel Standard (RFS). A assimetria emerge pelo fato de RFS dar ao etanol brasileiro a classificação de Biocombustível Avançado, tornando-o para os Estados Unidos um produto mais nobre que o etanol derivado do amido de milho produzido domesticamente. Apesar dos processos produtivos tornarem os dois produtos diferenciados quanto ao teor de emissão de CO2 em seus ciclos de vida, o produto final é o mesmo: etanol anidro combustível. Portanto, quando a aquisição de etanol brasileiro pelos Estados Unidos é tal que torna o balanço do-méstico de oferta e demanda deficitário no Brasil, faz-se necessária a importação brasileira de etanol americano. Esse vai e vem do produto ocorre de forma simultâ-nea e, por isso, considera-se a existência de um fluxo redundante de etanol, geran-do custos logísticos, transacionais e emissões de CO2 que poderiam ser evitados. Dado que o objeto do interesse americano pelo produto brasileiro é o baixo índice de emissões de CO2 no ciclo de vida do etanol de cana de açúcar, o fluxo redun-dante de etanol pode ser substituído por transações de Créditos de Biocombustível Avançado, uma nova ideia que é desenvolvida ao longo deste trabalho. Para cada Crédito transacionado, os Estados Unidos contabilizarão em seu balanço a emissão de CO2 correspondente ao volume equivalente de etanol de cana de açúcar, trans-ferindo para o Brasil as emissões correspondentes ao mesmo volume de etanol de-rivado do amido de milho. A substituição do fluxo físico pela transação de contratos é a fonte de economia proposta no título deste trabalho.

Negros misturados: um estudo de caso sobre identidades negras em Mossoró-RN

With more or less 213.000 habitants, Mossoró is the second more developed city from the Rio Grande do Norte. The town is proclamated like the land of freedom. To so far, exist four moments in your history related with the defence of freedom that is point like truthful from so proclamation. Suchlike happenings are the first female vote on Brazil, the resistance against the Lampião s band, the worman s mutiny and the slave release in 1883, five year before the Áurea law sanction. These happenings are commemorate yearly on setember with one big theatrical event called by the freedom high. Inside this contexto of exaltation to freedom, there is one black movement by name black and beautiful. Is the present dissertation, talked about the building of black identities between the black militants of Mossoró and the dwellers from the Santo Antônio district. With such approach, we intend to think about possibles differences or likeness, how the militants and dwellers from the refered district self-calleds like blacks or not. We are understanding black identity like one process to self-affirmation done by specificities of the social context and the individual particularity. This way, the identity change into one dynamic and contextual reality, gone always by one business process against the interaction of the social actors. So we search to discuss the specificities that involve the process to building of black identities in the city of freedom