Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

A broad perspective of various factors influencing alkene selenenylation has been developed by concurrent detailed analysis of key experimental and theoretical data, such as asymmetric induction, stereochemistry, relative reactivities, and comparison with that of alkene sulfenylation. Alkyl group branching a to the double bond was shown to have the greatest effect on alkene reactivity and the stereochemical outcome of corresponding addition reactions. This is in sharp contrast with other additions to alkenes, which depend more on the degree of substitution on C=C or upon substituent electronic effects. Electronic and steric effects influencing asymmetric induction, stereochemistry, regiochemistry, and relative reactivities in the addition of PhSeOTf to alkenes are compared and contrasted with those of PhSCl.

New strategies for the total synthesis of aza-propellane natural products

The propellane alkaloids comprise a large class of natural products that possess varying degrees of structural complexity and biological activity. The earliest of these to be isolated was acutumine, a chlorinated alkaloid that has been shown to exhibit selective T-cell cytotoxicity and antiamnesic properties. Alternatively, the hasubanan family of natural products has garnered considerable attention from the synthetic community in part due to its structural similarities to morphine. While these alkaloids have been the subject of numerous synthetic studies over the last forty years, very few enantioselective total syntheses have been reported to date.

As part of a research program directed towards the synthesis of various alkaloid natural products, we have developed a unified strategy for the preparation of the hasubanan and acutumine alkaloids. Specifically, a highly diastereoselective 1,2-addition of organometallic reagents to benzoquinone-derived tert-butanesulfinimines was established, which provides access to enantioenriched 4-aminocyclohexadienone products. This methodology enabled the enantioselective construction of functionalized dihydroindolones, which were found to undergo intramolecular Friedel-Crafts conjugate additions to furnish the propellane cores of several hasubanan alkaloids. As a result of these studies, the first enantioselective total syntheses of 8-demethoxyrunanine and cepharatines A, C, and D were accomplished in 9-11 steps from commercially available starting materials.

More recent efforts have focused on applying the sulfinimine methodology to the synthesis of a more structurally complex propellane alkaloid, acutumine. Extensive studies have determined that a properly functionalized dihydroindolone undergoes a photochemical [2+2] cycloaddition followed by a lactone fragmentation/Dieckmann cyclization to establish the carbocyclic framework of the natural product. The preparation of more appropriately oxidized propellane intermediates is currently under investigation, and is anticipated to facilitate our synthetic endeavors toward acutumine.

Some freshwater ostracods (Crustacea: Ostracoda) from South Wales

As background to a study of the application of astracods in environmental archaeology, a number of sites in South Wales were visited and sampled. Sites included seven broad environmental categories consisting of lakes, permanent ponds, non-permanent ponds, semi-static canals and reens (drainage ditches), non-permanent small lotic water-bodies, permanent fast-flowing waters and wells. In all, twenty-three species were recorded, and with one exception all belonged to the predominately freshwater Cypridoidea. Overall the most commonly encountered species in South Wales was Cypria ophthalmica. Comparing finds with earlier records, it would appear that Ilyocypris bradyi, Candona pratensis, Eucypris lilljeborgi, Herpetocypris chevreuxi, Potamocypris variegata, P. similis and P. pallida are new additions to the Welsh fauna.

Políticas da ação afirmativa e acesso ao ensino superior: os impactos institucionais da introdução das leis de reserva de vagas na UERJ

O objetivo desse trabalho de pesquisa foi realizar uma análise sobre o impacto institucional na política de acesso à UERJ, a partir da implementação da Lei n. 3542/2000, que destina 50% das vagas para alunos oriundos da rede pública de ensino e da Lei n. 3708/2001, que prevê 40% das vagas para pretos e pardos, com ênfase maior para afro-descendentes. Por meio dela, tive a intenção de contribuir com o debate sobre a agenda de ações afirmativas para a inclusão da população negra na universidade pública brasileira. De certa maneira, as políticas de ação afirmativa (AA) vieram problematizar o conceito de igualdade de direito, edificado a partir de experiências revolucionárias como nos EUA, França, Inglaterra, Índia, entre outros países. Essas políticas foram concebidas com a intenção de não privilegiar determinados grupos, mas assegurar para todos o mesmo tratamento perante a lei. O espaço da universidade escolhido para desenvolver a pesquisa foi o Conselho Superior de Ensino, Pesquisa e Extensão (Csepe) e o Conselho Universitário (Consun), duas instâncias fundamentais para a gestão da Universidade do Estado do Rio de Janeiro, à medida que definem e deliberam sobre as políticas a serem implementadas pela Universidade. Nesses Conselhos, pude ler e analisar Atas das sessões do Csepe e do Consun realizadas no período de 2000 a 2003, assim como pautas das reuniões de ambos os Conselhos no período de 1990 a 2003. Por meio dessa leitura e análise, pude identificar singularidades do processo de gestão universitária, refletindo sobre o quanto os caminhos trilhados podem contribuir para a construção de alternativas de democratização do ensino superior público no país e como instrumento de combate ao racismo.

The Federal Fisheries Service, 1871–1940: Its Origins, Organization, and Accomplishments

The U.S. Fish Commission was initiated in 1871 with Spencer Fullerton Baird as the first U.S. Fish Commissioner as an independent entity. In 1903 it became a part of the new U.S. Department of Commerce and Labor and was renamed the Bureau of Fisheries, a name it retained when the Departments of Commerce and Labor were separated in 1912. The Bureau remained in the Commerce Department until 1941 when it was merged with the Biological Survey and placed in the Department of Interior as the U.S. Fish and Wildlife Service. It was a scientific agency with well conceived programs of action, and it provided knowledge, advice, and example to state governments and individuals with fisheries interests and needs. Its efforts were supported by timely international agreements which constituted the precedent for Federal interest in fishery matters. The Fisheries Service earned stature as an advisor through heavy emphasis on basic biological research. The lack of such knowledge was marked and universal in the 1870’s, but toward the end of that decade, strong steps had been taken to address those needs under Baird’s leadership. USFC research activities were conducted cooperatively with other prominent scientists in the United States and abroad. Biological stations were established, and the world’s first and most productive deepsea research vessel, the Albatross, was constructed, and its 40-year career gave a strong stimulus to the science of oceanography. Together, the agency’s scientists and facilities made important additions to the sum of human knowledge, derived principles of conservation which were the vital bases for effective regulatory legislation, conducted extensive fish cultural work, collected and disseminated fisheries statistics, and began important research in methods of fish harvesting, preservation, transportation, and marketing.

Quantificação de metais e arsênio em aerossóis grossos, finos, ultrafinos e nanoparticulados por ICP-OES em ar ambiente e emissões veiculares de motores operando com diesel/biodiesel

Na frota automotiva nacional, veículos movidos a diesel e biodiesel são utilizados em larga e pequena escala, respectivamente, fazendo com que haja uma preocupação com os gases da exaustão provenientes destes motores. Ao ser fabricado, o veículo passa por testes rigorosos das emissões gasosas, segundo as regras do PROCONVE. Porém, estes testes regulam apenas as substâncias químicas contidas na legislação vigente, cujos riscos à saúde humana e ao meio ambiente são conhecidos. Portanto, conhecer o maior número de componentes ainda não contemplados pela legislação, em especial metais no material particulado, é de suma importância para subsidiar futuras alterações e inclusões na lista de componentes regulados. De acordo com o tamanho das partículas do material particulado, podendo chegar a escalas nanométricas, a inalação deste material pode causar lesões graves no organismo, pois têm a capacidade de atingir órgãos internos. O estudo é baseado na amostragem do material particulado proveniente dos gases de motores alimentados com diesel e/ou biodiesel em diferentes proporções de combustível e ar ambiente com impactador em cascata; determinando metais e arsênio na atmosfera de diferentes localidades do estado do Rio de Janeiro e no material particulado dos gases de escape de motores de ônibus/caminhão (EURO III), por intermédio de abertura ácida do material coletado e da técnica analítica ICP-OES. Os resultados obtidos para motor EURO III variaram de 100 a 10000 ng m-3, com a redução de emissão conforme adição de biodiesel no diesel sendo comprovada. Porém, em todas as proporções de combustíveis empregadas, houve grande incidência de emissão de partículas em escala manométrica, sendo esse comportamento também observado nas amostragens em ar ambiente. Neste caso, teores de 1,0 a 45,0 ng m-3 evidenciaram Caxias e Madureira como locais mais poluídos dos amostrados. Ni é o metal que possui situação mais alarmante, pois em todos os tamanhos de partícula e locais amostrados, os teores deste elemento foram superiores ao permitido pela legislação internacional. A análise estatística multivariada propôs que os combustíveis B10 e B15 são quimicamente semelhantes, enquanto B5 e B20 sofrem fortes alterações no decorrer de sua combustão e a correlação de Pearson mostrou em ar ambiente, que locais com níveis próximos de poluição apresentaram similaridade nos resultados, a qualidade do ar de Madureira é afetado predominantemente pela construção civil e tráfego, a presença da Baía de Guanabara ao redor da Cidade Universitária influencia nas emissões, a refinaria em Caxias é responsável por emissões importantes de metais e no Parque Nacional de Itatiaia , ao contrário de que se supunha, não está totalmente livre de poluição

Copper-nickel alloys for marine aquacultural engineering

Engineering developments, problems of marine corrosion, fouling and practical innovative applications of copper-nickel alloys in comparison with other materials for marine aquacultural engineering are presented. Coefficient of drag and hydrodynamic force acting on nylon and polyethylene net enclosures have shown a four-fold increase of force in four months at the Cochin harbour due to fouling. Corrosion behaviour of copper-nickel and other copper base alloys are also presented. Effects of copper additions to culture water are reviewed.

Optical emission spectroscopy of the plasma during sputter deposition of YBCO films for microwave applications

YBCO thin films are currently used in several HTS-based electronics applications. The performance of devices, which may include microwave passive components (filters, resonators), grain boundary junctions or spintronic multilayer structures, is determined by film quality, which in turn depends on the deposition technology used and growth parameters. We report on results from nonintrusive Optical Emission Spectroscopy of the plasma during YBCO thin film deposition in a high-pressure on-axis sputtering system under different conditions, including small trace gas additions to the sputtering gas. We correlate these results with the compositional and structural changes which affect the DC and microwave properties of YBCO films. Film morphology, composition, structure and in- and out-of-plane orientation were assessed; T, and microwave surface resistance measurements were made using inductive and resonator techniques. Comparison was made with films sputtered in an off-axis 2-opposing magnetron system.

Biologically Inspired Tensor Features

According to the research results reported in the past decades, it is well acknowledged that face recognition is not a trivial task. With the development of electronic devices, we are gradually revealing the secret of object recognition in the primate's visual cortex. Therefore, it is time to reconsider face recognition by using biologically inspired features. In this paper, we represent face images by utilizing the C1 units, which correspond to complex cells in the visual cortex, and pool over S1 units by using a maximum operation to reserve only the maximum response of each local area of S1 units. The new representation is termed C1 Face. Because C1 Face is naturally a third-order tensor (or a three dimensional array), we propose three-way discriminative locality alignment (TWDLA), an extension of the discriminative locality alignment, which is a top-level discriminate manifold learning-based subspace learning algorithm. TWDLA has the following advantages: (1) it takes third-order tensors as input directly so the structure information can be well preserved; (2) it models the local geometry over every modality of the input tensors so the spatial relations of input tensors within a class can be preserved; (3) it maximizes the margin between a tensor and tensors from other classes over each modality so it performs well for recognition tasks and (4) it has no under sampling problem. Extensive experiments on YALE and FERET datasets show (1) the proposed C1Face representation can better represent face images than raw pixels and (2) TWDLA can duly preserve both the local geometry and the discriminative information over every modality for recognition.

Les manuscrits latins de la Chirurgia d'Albucasis et la lexicographie du latin m?di?val

Trotter, David, 'Les manuscrits latins de la Chirurgia d'Albucasis et la lexicographie du latin m?di?val', Archivum Latinitatis Medii Aevi (Bulletin Du Cange) (2001) 59(1) pp.181-202 RAE2008

Grignard Reaction - Synthesis of Substituted Benzoic Acids

A convenient preparation of substituted benzoic acids from Grignard additions to solid carbon dioxide. Students create a library of carboxylic acids by using differentially substituted, commercially available aryl bromides, which can be used as the starting materials for a multistep synthesis. This is a modification and improvement of a very popular undergraduate organic chemistry experiment.

Load Profiling for Efficient Route Selection in Multi-Class Networks

High-speed networks, such as ATM networks, are expected to support diverse Quality of Service (QoS) constraints, including real-time QoS guarantees. Real-time QoS is required by many applications such as those that involve voice and video communication. To support such services, routing algorithms that allow applications to reserve the needed bandwidth over a Virtual Circuit (VC) have been proposed. Commonly, these bandwidth-reservation algorithms assign VCs to routes using the least-loaded concept, and thus result in balancing the load over the set of all candidate routes. In this paper, we show that for such reservation-based protocols|which allow for the exclusive use of a preset fraction of a resource's bandwidth for an extended period of time-load balancing is not desirable as it results in resource fragmentation, which adversely affects the likelihood of accepting new reservations. In particular, we show that load-balancing VC routing algorithms are not appropriate when the main objective of the routing protocol is to increase the probability of finding routes that satisfy incoming VC requests, as opposed to equalizing the bandwidth utilization along the various routes. We present an on-line VC routing scheme that is based on the concept of "load profiling", which allows a distribution of "available" bandwidth across a set of candidate routes to match the characteristics of incoming VC QoS requests. We show the effectiveness of our load-profiling approach when compared to traditional load-balancing and load-packing VC routing schemes.

Trade & Cap: A Customer-Managed, Market-Based System for Trading Bandwidth Allowances at a Shared Link

We propose Trade & Cap (T&C), an economics-inspired mechanism that incentivizes users to voluntarily coordinate their consumption of the bandwidth of a shared resource (e.g., a DSLAM link) so as to converge on what they perceive to be an equitable allocation, while ensuring efficient resource utilization. Under T&C, rather than acting as an arbiter, an Internet Service Provider (ISP) acts as an enforcer of what the community of rational users sharing the resource decides is a fair allocation of that resource. Our T&C mechanism proceeds in two phases. In the first, software agents acting on behalf of users engage in a strategic trading game in which each user agent selfishly chooses bandwidth slots to reserve in support of primary, interactive network usage activities. In the second phase, each user is allowed to acquire additional bandwidth slots in support of presumed open-ended need for fluid bandwidth, catering to secondary applications. The acquisition of this fluid bandwidth is subject to the remaining "buying power" of each user and by prevalent "market prices" – both of which are determined by the results of the trading phase and a desirable aggregate cap on link utilization. We present analytical results that establish the underpinnings of our T&C mechanism, including game-theoretic results pertaining to the trading phase, and pricing of fluid bandwidth allocation pertaining to the capping phase. Using real network traces, we present extensive experimental results that demonstrate the benefits of our scheme, which we also show to be practical by highlighting the salient features of an efficient implementation architecture.

Building effectiveness communication ratios (BECs): an integrated ‘life-cycle’ methodology for mitigating energy-use in buildings

Current building regulations are generally prescriptive in nature. It is widely accepted in Europe that this form of building regulation is stifling technological innovation and leading to inadequate energy efficiency in the building stock. This has increased the motivation to move design practices towards a more ‘performance-based’ model in order to mitigate inflated levels of energy-use consumed by the building stock. A performance based model assesses the interaction of all building elements and the resulting impact on holistic building energy-use. However, this is a nebulous task due to building energy-use being affected by a myriad of heterogeneous agents. Accordingly, it is imperative that appropriate methods, tools and technologies are employed for energy prediction, measurement and evaluation throughout the project’s life cycle. This research also considers that it is imperative that the data is universally accessible by all stakeholders. The use of a centrally based product model for exchange of building information is explored. This research describes the development and implementation of a new building energy-use performance assessment methodology. Termed the Building Effectiveness Communications ratios (BECs) methodology, this performance-based framework is capable of translating complex definitions of sustainability for energy efficiency and depicting universally understandable views at all stage of the Building Life Cycle (BLC) to the project’s stakeholders. The enabling yardsticks of building energy-use performance, termed Ir and Pr, provide continuous design and operations feedback in order to aid the building’s decision makers. Utilised effectively, the methodology is capable of delivering quality assurance throughout the BLC by providing project teams with quantitative measurement of energy efficiency. Armed with these superior enabling tools for project stakeholder communication, it is envisaged that project teams will be better placed to augment a knowledge base and generate more efficient additions to the building stock.

Solo and Chamber Music of Pulitzer Prize-Winning Composers

The Pulitzer Prize in Music, established in 1943, is one of America's most prestigious awards. It has been awarded to fifty-three composers for a "distinguished musical composition of significant dimension by an American that has had its first performance in the United States during the year." Composers who have won the Pulitzer Prize are considered to be at the pinnacle of their creativity and have provided the musical world with classical music compositions worthy of future notice. By tracing the history of Pulitzer Prize-winning composers and their compositions, researchers and musicians enhance their understanding of the historical evolution of American music, and its impact on American culture. Although the clarinet music of some of these composers is rarely performed today, their names will be forever linked to the Pulitzer, and because of that, their compositions will enjoy a certain sense of immortality. Of the fifty-four composers who have won the award, forty-seven have written for the clarinet in a solo or chamber music setting (five or less instruments). Just as each Pulitzer Prize-winning composition is a snapshot of the state of American music at that time, these works trace the history of American clarinet musical development, and therefore, they are valuable additions to the clarinet repertoire and worthy of performance. This dissertation project consists of two recitals featuring the solo and chamber clarinet music of sixteen Pulitzer Prize-winning composers, extended program notes containing information on each composer's life, their music, the Pulitzer Prize-winning composition and the recital selection, and a complete list of all Pulitzer Prize-winning composers and their solo and chamber clarinet music. Featured Composers Dominick Argento, To Be Sung Upon the Water Leslie Bassett, Soliloquies William Bolcom, Little Suite of Four Dances Aaron Copland, As it Fell Upon a Day John Corigliano, Soliloquy Norman Dello Joio, Concertante Morton Gould, Benny's Gig Charles Ives, Largo Douglas Moore, Quintet for Clarinet and Strings George Perle, Three Sonatas Quincy Porter, Quintet for Clarinet and Strings Mel Powell, Clarinade Shulamit Ran, Private Game Joseph Schwantner, Entropy Leo Sowerby, Sonata Ernst Toch, Adagio elegiaco