1,377 research outputs found

    Methylation of hen erythrocyte DNA

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    AbstractWe have analysed the 5-methylcytosine content of hen erythrocyte DNA and found it to be lower than that of DNA from other chick tissues analysed. Erythrocyte DNA is also a better substrate for DNA methylase having a five-fold lower Km than DNA from white blood cells. This is probably because it contains a large number of hemimethylated sites.Thus the inverse correlation between methylation and gene expression does not apply to the chick red blood cell

    Single-photon stored-light Ramsey interferometry using Rydberg polaritons

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    We demonstrate a single-photon stored-light interferometer, where a photon is stored in a laser-cooled atomic ensemble in the form of a Rydberg polariton with a spatial extent of 10×1×1µm3. The photon is subject to a Ramsey sequence, i.e., “split” into a superposition of two paths. After a delay of up to 450 ns, the two paths are recombined to give an output dependent on their relative phase. The superposition time of 450 ns is equivalent to a free-space propagation distance of 135 m. We show that the interferometer fringes are sensitive to external fields and suggest that stored-light interferometry could be useful for localized sensing applications

    Overlap lattice fermion in a gravitational field

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    We construct a lattice Dirac operator of overlap type that describes the propagation of a Dirac fermion in an external gravitational field. The local Lorentz symmetry is manifestly realized as a lattice gauge symmetry, while it is believed that the general coordinate invariance is restored only in the continuum limit. Our doubler-free Dirac operator satisfies the conventional Ginsparg-Wilson relation and possesses gamma_5 hermiticity with respect to the inner product, which is suggested by the general coordinate invariance. The lattice index theorem in the presence of a gravitational field holds, and the classical continuum limit of the index density reproduces the Dirac genus. Reduction to a single Majorana fermion is possible for 8k+2 and 8k+4 dimensions, but not for 8k dimensions, which is consistent with the existence of the global gravitational/gauge anomalies in 8k dimensions. Other Lorentz representations, such as the spinor-vector and the bi-spinor representations, can also be treated. Matter fields with a definite chirality (with respect to the lattice-modified chiral matrix) are briefly considered.Comment: 22 pages, uses PTPTeX.cls, the final version to appear in Prog. Theor. Phy

    Evolution of small putative group I introns in the SSU rRNA gene locus of Phialophora species

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    <p>Abstract</p> <p>Background</p> <p>Group I introns (specifically subgroup IC1) are common in the nuclear ribosomal RNA genes of fungi. While most range in length from more than 200 to nearly 1800 nucleotides (nt) in length, several small putative (or degenerate) group I introns have been described that are between 56 and 81 nt. Although small, previously we demonstrated that the <it>Pa</it>SSU intron in the rRNA small subunit gene of <it>Phialophora americana </it>isolate Wang 1046 is capable of <it>in vitro </it>splicing using a standard group I intron pathway, thus qualifying it as a functional ribozyme.</p> <p>Findings</p> <p>Here, we describe eight short putative group I introns, ranging in length from 63 to 75 nt, in the rRNA small subunit genes of <it>Phialophora </it>isolates, a fungal genus that ranges from saprobic to pathogenic on plants and animals. All contain putative pairing regions P1, P7, and P10, as well as a pairing region formed between the middle of the intron and part of the 3' exon. The other pairing regions common in the core of standard group I introns are absent. However, parts of the 3' exon may aid in the stabilization of these small introns. Although the eight putative group I introns were from at least three species of <it>Phialophora</it>, phylogenetic analysis indicated that the eight are monophyletic. They are also monophyletic with the small introns of two lichen-forming fungi, <it>Porpidia crustulata </it>and <it>Arthonia lapidicola</it>.</p> <p>Conclusions</p> <p>The small putative group I introns in <it>Phialophora </it>have common features that may represent group I introns at their minima. They appear to have a single origin as indicated by their monophyly in phylogenetic analyses.</p

    Extended Knowledge-How

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    According to reductive intellectualists about knowledge-how :147–190, 2008; Philos Phenomenol Res 78:439–467, 2009) knowledge-how is a kind of knowledge-that. To the extent that this is right, then insofar as we might conceive of ways knowledge could be extended with reference to active externalist :7–19, 1998; Clark in Supersizing the mind: embodiment, action, and cognitive extension: embodiment, action, and cognitive extension. Oxford University Press, Oxford, 2008) approaches in the philosophy of mind, we should expect no interesting difference between the two. However, insofar as anti-intellectualist approaches to knowledge-how are a viable option, there is an overlooked issue of how knowledge-how might be extended, via active externalism, in ways very differently from knowledge-that. This paper explores this overlooked space, and in doing so, illustrates how a novel form of extended knowledge-how emerges from a pairing of active externalism in the philosophy of mind with anti-intellectualism in the theory of knowledge. Crucial to our argument will be a new way of thinking about the extended mind thesis, as it pertains to the kinds of state one is in when one knows how to do something, and how this state connects with non-accidentally successful performanc

    A tela em limites: projeções sobre a superfície urbana

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    Trabalho de Conclusão de Curso apresentado ao Instituto Latino-Americano de Arte, Cultura e História da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Bacharel em Cinema e Audiovisual. Orientador: Fabio Allan Mendes RamalhoNestas últimas décadas, houve um crescente avanço tecnológico digital em diversas áreas do ramo, gerou-se assim um barateamento considerável em equipamentos eletrônicos, principalmente em relação ao audiovisual. Esse baixo custo bem como as inovações tecnológicas, fizeram com que o audiovisual pudesse alcançar outros modos de exibição, e desta maneira, abrindo um leque de possibilidades para diferentes jeitos de se fazer arte com as imagens, com o vídeo e com o áudio. O VJ é um desses artistas desta nova safra, que se utiliza de diversas linguagens audiovisuais e traz consigo um apanhado de novas representações artísticas tanto visuais quanto sonoras, como é o caso do VJing e projeções mapeadas por exemplo. Esta pesquisa faz questão de apresentar esse universo do audiovisual, proporcionando assim uma maior visibilidade à algumas performances pouco conhecidas pelo público em geral. Deste modo, foi escolhido dentre tantos artistas audiovisuais contemporâneo, o duo VJ Suave, sua performance Suaveciclo e seu curta-metragem Homeless, para poder contextualizar esses novos meios audiovisuais contemporâneos de se fazer arte.En estas últimas décadas, hubo un creciente avance tecnológico digital en diversas áreas del campo, se generó así un abaratamiento considerable en equipos electrónicos, principalmente con relación al audiovisual. Este bajo costo, así como las innovaciones tecnológicas, hicieron que el audiovisual pudiera alcanzar otros modos de exhibición, y de esta manera, se abrió un abanico de posibilidades para diferentes maneras de hacer arte con las imágenes, con el vídeo y con el audio. El VJ es uno de esos artistas de esta nueva generación, que utiliza diversos lenguajes audiovisuales y trae consigo un repertorio de nuevas representaciones artísticas tanto visuales como sonoras, como es el caso del VJing y proyecciones mapeadas por ejemplo. Esta investigación hace cuestión de presentar ese universo del audiovisual, proporcionando así una mayor visibilidad a algunas performances poco conocidas por el público en general. De este modo, fue elegido entre tantos artistas audiovisuales contemporáneos, el dúo VJ Suave, su performance Suaveciclo y su cortometraje Homeless, para poder contextualizar esos nuevos medios audiovisuales contemporáneos de hacerse art

    Ab initio

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    Improving the design of industrial microwave processing systems through prediction of the dielectric properties of complex multi-layered materials

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    Rigorous design of industrial microwave processing systems requires in-depth knowledge of the dielectric properties of the materials to be processed. These values are not easy to measure, particularly when a material is multi-layered containing multiple phases, when one phase has a much higher loss than the other and the application is based on selective heating. This paper demonstrates the ability of the Clausius-Mossotti (CM) model to predict the dielectric constant of multi-layered materials. Furthermore, mixing rules and graphical extrapolation techniques were used to further evidence our conclusions and to estimate the loss factor. The material used for this study was vermiculite, a layered alumina-silicate mineral containing up to 10 % of an interlayer hydrated phase. It was measured at different bulk densities at two distinct microwave frequencies, namely 934 and 2143 MHz. The CM model, based on the ionic polarisability of the bulk material, gives only a prediction of the dielectric constant for experimental data with a deviation of less than 5 % at microwave frequencies. The complex refractive index model (CRIM), Landau, Lifshitz and Loyenga (LLL), Goldschmidt, Böttcher and Bruggeman-Hanai model equations are then shown to give a strong estimation of both dielectric constant and loss factor of the solid material compared to that of the measured powder with a deviation of less than 1 %. Results obtained from this work provide a basis for the design of further electromagnetic processing systems for multi-layered materials consisting of both high loss and low loss components
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