491 research outputs found

    Low Timing Jitter Detector for Gigahertz Quantum Key Distribution

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    A superconducting single-photon detector based on a niobium nitride nanowire is demonstrated in an optical-fibre-based quantum key distribution test bed operating at a clock rate of 3.3 GHz and a transmission wavelength of 850 nm. The low jitter of the detector leads to significant reduction in the estimated quantum bit error rate and a resultant improvement in the secrecy efficiency compared to previous estimates made by use of silicon single-photon avalanche detectors.Comment: 11 pages, including 2 figure

    UNITSIM-Galaxies: Data release and clustering of emission-line galaxies

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    This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Monthly Notices of the Royal Astronomical Society 510.4 (2022): 5392-5407 is available online at: https://academic.oup.com/mnras/article-abstract/510/4/5392/6505155?redirectedFrom=fulltextNew surv e ys such as European Space Agenc ys (ESA's) Euclid mission are planned to map with unprecedented precision the large-scale structure of the Universe by measuring the 3D positions of tens of millions of galaxies. It is necessary to develop theoretically modelled galaxy catalogues to estimate the expected performance and to optimize the analysis strategy of these surv e ys. We populate two pairs of (1 h -1 Gpc) 3 volume dark matter-only simulations from the UNIT project with galaxies using the Semi-Analytic Galaxy Evolution semi-analytic model of galaxy formation, coupled to the photoionization model GET EMLINES to estimate their H αemission. These catalogues represent a unique suite that includes galaxy formation physics and -thanks to the fixed-pair technique used -an ef fecti ve volume of ∼(5 h -1 Gpc ) 3 , which is several times larger than the Euclid surv e y. We present the performance of these data and create five additional emission-line galaxy (ELG) catalogues by applying a dust-attenuation model as well as adjusting the flux threshold as a function of redshift in order to reproduce Euclid-forecast d N /d z values. As a first application, we study the abundance and clustering of those model H αELGs: For scales greater than ∼5 h -1 Mpc, we find a scale- independent bias with a value of b ∼1 at redshift z ∼0.5, that can increase nearly linearly to b ∼4 at z ∼2, depending on the ELG catalogue. Model galaxy properties, including their emission-line fluxes (with and without dust extinction) are publicly availabl

    1981: Abilene Christian College Bible Lectures - Full Text

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    Our Uncommon Commitment Being the Abilene Christian University Annual Bible Lectures 1981 Published by Abilene Christian University Book Store ACU Station Abilene, Texas 7969

    Differential Therapeutic Outcomes of Community-Based Group Interventions for Women and Children Exposed to Intimate Partner Violence

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    Two community-based group therapies, emotion focused versus goal oriented, are compared among women exposed to intimate partner violence (n = 46) and their children ( n = 48) aged between 6 and 12 years. A series of repeated measures analyses are employed to evaluate the effects of time from baseline to postintervention following random assignment. Main and treatment effects for women provide support for the relative effectiveness in increasing quality of social support in the emotion-focused intervention and in the reduction of both family conflict and alcohol use for the goal-oriented intervention.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Origins of the Ambient Solar Wind: Implications for Space Weather

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    The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

    Cosmic CARNage II: the evolution of the galaxy stellar mass functionin observations and galaxy formation models

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    We present a comparison of the observed evolving galaxy stellar mass functions with the predictions of eight semi-analytic models and one halo occupation distribution model. While most models are able to fit the data at low redshift, some of them struggle to simultaneously fit observations at high redshift. We separate the galaxies into ‘passive’ and ‘star-forming’ classes and find that several of the models produce too many low-mass star-forming galaxies at high redshift compared to observations, in some cases by nearly a factor of 10 in the redshift range 2.5 < z < 3.0. We also find important differences in the implied mass of the dark matter haloes the galaxies inhabit, by comparing with halo masses inferred from observations. Galaxies at high redshift in the models are in lower mass haloes than suggested by observations, and the star formation efficiency in low-mass haloes is higher than observed. We conclude that many of the models require a physical prescription that acts to dissociate the growth of low-mass galaxies from the growth of their dark matter haloes at high redshift
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