55,249 research outputs found

    Hamster leukemia virus: lack of endogenous DNA synthesis and unique structure of its DNA polymerase

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    Infectious hamster leukemia virus (HaLV) contains a DNA polymerase different from those of murine and avian viruses. No endogenous reaction directed by the 60 to 70S RNA of HaLV could be demonstrated in detergenttreated HaLV virions, nor could the purified DNA polymerase copy added viral RNA. The virion RNA could, however, act as template for added avian myeloblastosis virus DNA polymerase and the HaLV DNA polymerase could efficiently utilize homopolymers as templates. The HaLV enzyme was like other reverse transcriptases in that certain ribohomopolymers were much better templates than the homologous deoxyribohomopolymers. No ribonuclease H activity could be shown in the HaLV enzyme, but neither could activity be found in the murine leukemia virus DNA polymerase. The hamster enzyme was unique in that poly(A) ·oligo(dT) was a poor template, and globin mRNA primed with oligo(dT) was totally inactive as a template. Its uniqueness was also indicated by its subunit composition; electrophoresis of the HaLV DNA polymerase in sodium dodecyl sulfate-containing polyacrylamide gels revealed equimolar amounts of two polypeptides of molecular weight 68,000 and 53,000. The sedimentation rate of the enzyme in glycerol gradients was consistent with a structure containing one each of the two polypeptides. The enzyme thus appears to be structurally distinct from other known virion DNA polymerases. Its inability to carry out an endogenous reaction in vitro might result from an inability to utilize certain primers

    Entangled Husimi distribution and Complex Wavelet transformation

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    Based on the proceding Letter [Int. J. Theor. Phys. 48, 1539 (2009)], we expand the relation between wavelet transformation and Husimi distribution function to the entangled case. We find that the optical complex wavelet transformation can be used to study the entangled Husimi distribution function in phase space theory of quantum optics. We prove that the entangled Husimi distribution function of a two-mode quantum state |phi> is just the modulus square of the complex wavelet transform of exp{-(|eta|^2)/2} with phi(eta)being the mother wavelet up to a Gaussian function.Comment: 7 page

    Solution of the dual reflection equation for An−1(1)A^{(1)}_{n-1} SOS model

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    We obtain a diagonal solution of the dual reflection equation for elliptic An−1(1)A^{(1)}_{n-1} SOS model. The isomorphism between the solutions of the reflection equation and its dual is studied.Comment: Latex file 12 pages, added reference

    Measuring the Deviation from the Linear and Deterministic Bias through Cosmic Gravitational Lensing Effects

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    Since gravitational lensing effects directly probe inhomogeneities of dark matter, lensing-galaxy cross-correlations can provide us important information on the relation between dark matter and galaxy distributions, i.e., the bias. In this paper, we propose a method to measure the stochasticity/nonlinearity of the galaxy bias through correlation studies of the cosmic shear and galaxy number fluctuations. Specifically, we employ the aperture mass statistics MapM_{ap} to describe the cosmic shear. We divide the foreground galaxy redshift zf<zsz_f<z_s into several bins, where zsz_s is the redshift of the source galaxies, and calculate the quantity 2/^2/ for each redshift bin. Then the ratio of the summation of 2/<Ng2(zf)>^2/< N_g^2(z_f)> over the bins to gives a measure of the nonlinear/stochastic bias. Here Ng(zf)N_g(z_f) is the projected surface number density fluctuation of foreground galaxies at redshift zfz_f, and MapM_{ap} is the aperture mass from the cosmic-shear analysis. We estimate that for a moderately deep weak-lensing survey with zs=1z_s=1, source galaxy surface number density nb=30gal/arcmin2n_b=30 \hbox {gal}/\hbox {arcmin}^2 and a survey area of 25deg225 \hbox {deg}^2, the effective rr-parameter that represents the deviation from the linear and deterministic bias is detectable in the angular range of 1'-10' if |r-1|\gsim 10%. For shallow, wide surveys such as the Sloan Digital Sky Survey with zs=0.5z_s=0.5, nb=5gal/arcmin2n_b=5 \hbox {gal}/\hbox {arcmin}^2, and a survey area of 104deg210^4 \hbox {deg}^2, a 10% detection of rr is possible over the angular range 1â€Č−100â€Č1'-100'.Comment: ApJ in pres

    Using schema transformation pathways for data lineage tracing

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    With the increasing amount and diversity of information available on the Internet, there has been a huge growth in information systems that need to integrate data from distributed, heterogeneous data sources. Tracing the lineage of the integrated data is one of the problems being addressed in data warehousing research. This paper presents a data lineage tracing approach based on schema transformation pathways. Our approach is not limited to one specific data model or query language, and would be useful in any data transformation/integration framework based on sequences of primitive schema transformations

    Feelbook: A social media app for teens designed to foster positive online behavior and prevent cyberbullying

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    This project presents a prototype for a stand-alone social media application designed for teenage users in order to prevent and mitigate mean and cruel online behavior. The purpose of the app is to create a nurturing environment where teenagers use a variety of features designed to help raise self-awareness of their own online behavior, seek support when needed, and learn to control and, when possible, correct aggressive behavior. The prototype is framed by four design principles: design for reflection, design for empathy, design for empowerment, and design for the whole. We conclude by outlining the next steps in our project to develop an application that helps to improve the online experiences of young people. This work has implications for the CHI community because it applies software solutions to tackle a critical social problem that can affect the health and well being of young people
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