31,459 research outputs found

    Improved table for cutting and welding

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    Welding table covered with parallel inverted steel angles improves metal torch cutting of various types and thicknesses

    Combining Full-Shape and BAO Analyses of Galaxy Power Spectra: A 1.6% CMB-independent constraint on H0

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    We present cosmological constraints from a joint analysis of the pre- and post-reconstruction galaxy power spectrum multipoles from the final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). Geometric constraints are obtained from the positions of BAO peaks in reconstructed spectra, analyzed in combination with the unreconstructed spectra in a full-shape (FS) likelihood using a joint covariance matrix, giving stronger parameter constraints than FS-only or BAO-only analyses. We introduce a new method for obtaining constraints from reconstructed spectra based on a correlated theoretical error, which is shown to be simple, robust, and applicable to any flavor of density-field reconstruction. Assuming Λ\LambdaCDM with massive neutrinos, we analyze data from two redshift bins zeff=0.38,0.61z_\mathrm{eff}=0.38,0.61 and obtain 1.6%1.6\% constraints on the Hubble constant H0H_0, using only a single prior on the current baryon density ωb\omega_b from Big Bang Nucleosynthesis (BBN) and no knowledge of the power spectrum slope nsn_s. This gives H0=68.6±1.1 km s−1Mpc−1H_0 = 68.6\pm1.1\,\mathrm{km\,s}^{-1}\mathrm{Mpc}^{-1}, with the inclusion of BAO data sharpening the measurement by 40%40\%, representing one of the strongest current constraints on H0H_0 independent of cosmic microwave background data. Restricting to the best-fit slope nsn_s from Planck (but without additional priors on the spectral shape), we obtain a 1%1\% H0H_0 measurement of 67.8±0.7 km s−1Mpc−167.8\pm 0.7\,\mathrm{km\,s}^{-1}\mathrm{Mpc}^{-1}. We find strong constraints on the cosmological parameters from a joint analysis of the FS, BAO, and Planck data. This sets new bounds on the sum of neutrino masses ∑mÎœ<0.14 eV\sum m_\nu < 0.14\,\mathrm{eV} (at 95%95\% confidence) and the effective number of relativistic degrees of freedom Neff=2.90−0.16+0.15N_\mathrm{eff} = 2.90^{+0.15}_{-0.16}, though contours are not appreciably narrowed by the inclusion of BAO data.Comment: 42 pages, 12 figures, accepted by JCAP, likelihoods available at https://github.com/Michalychforever/lss_montepython (minor typo corrected

    Lie point symmetries and the geodesic approximation for the Schr\"odinger-Newton equations

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    We consider two problems arising in the study of the Schr\"odinger-Newton equations. The first is to find their Lie point symmetries. The second, as an application of the first, is to investigate an approximate solution corresponding to widely separated lumps of probability. The lumps are found to move like point particles under a mutual inverse-square law of attraction

    Informed choice? How the United Kingdom's Key Information Set fails to represent pedagogy to potential students

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    This paper explores the ways in which information about course pedagogy has been represented to potential students through national descriptors and specifications such as the United Kingdom’s Key Information Set. It examines the extent to which such descriptors provide helpful information about pedagogy, for example innovative uses of technology. The paper starts by exploring the wider context within which these descriptors have been developed, including a comparison of similar descriptions internationally. This is followed by a comparative analysis, in which two courses (one single honours undergraduate degree, one Massive Open Online Course) are classified and compared. This serves to illustrate the blind spots in classifications such as the Key Information Set. The paper concludes by arguing that further work is needed to develop classification schemes that both address explicitly the interests of potential students and are able to represent the pedagogic decisions that differentiate teaching in contemporary higher education

    Specific recognition of a multiply phosphorylated motif in the DNA repair scaffold XRCC1 by the FHA domain of human PNK.

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    Short-patch repair of DNA single-strand breaks and gaps (SSB) is coordinated by XRCC1, a scaffold protein that recruits the DNA polymerase and DNA ligase required for filling and sealing the damaged strand. XRCC1 can also recruit end-processing enzymes, such as PNK (polynucleotide kinase 3'-phosphatase), Aprataxin and APLF (aprataxin/PNK-like factor), which ensure the availability of a free 3'-hydroxyl on one side of the gap, and a 5'-phosphate group on the other, for the polymerase and ligase reactions respectively. PNK binds to a phosphorylated segment of XRCC1 (between its two C-terminal BRCT domains) via its Forkhead-associated (FHA) domain. We show here, contrary to previous studies, that the FHA domain of PNK binds specifically, and with high affinity to a multiply phosphorylated motif in XRCC1 containing a pSer-pThr dipeptide, and forms a 2:1 PNK:XRCC1 complex. The high-resolution crystal structure of a PNK-FHA-XRCC1 phosphopeptide complex reveals the basis for this unusual bis-phosphopeptide recognition, which is probably a common feature of the known XRCC1-associating end-processing enzymes

    A new class of entanglement measures

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    We introduce new entanglement measures on the set of density operators on tensor product Hilbert spaces. These measures are based on the greatest cross norm on the tensor product of the sets of trace class operators on Hilbert space. We show that they satisfy the basic requirements on entanglement measures discussed in the literature, including convexity, invariance under local unitary operations and non-increase under local quantum operations and classical communication.Comment: Revised version accepted by J Math Phys, 12 pages, LaTeX, contains Sections 1-5 & 7 of the previous version. The previous Section 6 is now in quant-ph/0105104 and the previous Section 8 is superseded by quant-ph/010501
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