3,935 research outputs found

    Time-asymmetry of probabilities versus relativistic causal structure: an arrow of time

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    There is an incompatibility between the symmetries of causal structure in relativity theory and the signaling abilities of probabilistic devices with inputs and outputs: while time-reversal in relativity will not introduce the ability to signal between spacelike separated regions, this is not the case for probabilistic devices with space-like separated input-output pairs. We explicitly describe a non-signaling device which becomes a perfect signaling device under time-reversal, where time-reversal can be conceptualized as playing backwards a videotape of an agent manipulating the device. This leads to an arrow of time that is identifiable when studying the correlations of events for spacelike separated regions. Somewhat surprisingly, although time-reversal of Popuscu-Roerlich boxes also allows agents to signal, it does not yield a perfect signaling device. Finally, we realize time-reversal using post-selection, which could lead experimental implementation.Comment: 4 pages, some figures; replaces arXiv:1010.4572 [quant-ph

    Supplement: Going the Distance: Mapping Host Galaxies of LIGO and Virgo Sources in Three Dimensions Using Local Cosmography and Targeted Follow-up

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    This is a supplement to the Letter of Singer et al. (https://arxiv.org/abs/1603.07333), in which we demonstrated a rapid algorithm for obtaining joint 3D estimates of sky location and luminosity distance from observations of binary neutron star mergers with Advanced LIGO and Virgo. We argued that combining the reconstructed volumes with positions and redshifts of possible host galaxies can provide large-aperture but small field of view instruments with a manageable list of targets to search for optical or infrared emission. In this Supplement, we document the new HEALPix-based file format for 3D localizations of gravitational-wave transients. We include Python sample code to show the reader how to perform simple manipulations of the 3D sky maps and extract ranked lists of likely host galaxies. Finally, we include mathematical details of the rapid volume reconstruction algorithm.Comment: For associated data release, see http://asd.gsfc.nasa.gov/Leo.Singer/going-the-distanc

    Ursinus College Alumni Journal, November 1958

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    President\u27s page • President\u27s inaugural address • Dr. D. L. Helfferich inaugurated President of Ursinus College • Ursinus College opens with 839 • The Evening School • New preceptress at 944 • Library • The Messiah • The faculty cornered • The cornered faculty turns • Tracking the Alder Flycatcher • Old Timers\u27 Day almost rained out • Face lifting on campus • Ursinus Woman\u27s Club plans holiday luncheon • Ursinus Forum, 1958-59 • A challenge for alumni giving • Fall play Joan of Lorraine • Annual alumni Schoolmen\u27s Week luncheon • Five years of alumni sponsorship completed: 1958 Loyalty Fund report • Workshop in economic education • Paul S. Craigie, class Chairman of the year • Honor roll by classes • Contributors for the 1958 Loyalty Fund campaign • Varsity football • Varsity and J.V. basketball schedule 1958-59 • Alumnae continue winning ways • Varsity wrestling schedule 1959 • Two new assistant football coaches • Varsity has strong potential • Ursinus appoints a new wrestling coach • News about ourselves • Weddings • Births • Necrology • Two Spanish majors receive honorshttps://digitalcommons.ursinus.edu/alumnijournal/1063/thumbnail.jp

    Fission Barrier of Thallium-201

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    A new method involving the detection of fission fragments in mica has been applied to the measurement of the fission cross section of the compound nucleus Tl201 produced by bombardments of Au197 with helium ions. These data have been interpreted in terms of an expression for the ratio of fission to neutron-emission probabilities similar to those used conventionally, but modified to include the effect of quantum-mechanical barrier penetrability. In this way a height of 22.5±1.5 MeV was found for the fission barrier of Tl201 and a lower limit on the width could be established. The above value of the barrier, when interpreted on the basis of the liquid-drop theory, leads to an accurate determination of the ratio of the electrostatic to the surface energy of nuclei. This serves to establish the constant of proportionality between the "fissionability parameter" x and the value of Z2/A as follows: x=(Z2/A)/(48.4±0.5). This measured barrier height, when added to the ground-state mass of Tl201, gives a saddle-point mass of this nucleus equal to 200.9949±0.0015 mass units (carbon scale)

    Possible Role of Horizontal Gene Transfer in the Colonization of Sea Ice by Algae

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    Diatoms and other algae not only survive, but thrive in sea ice. Among sea ice diatoms, all species examined so far produce ice-binding proteins (IBPs), whereas no such proteins are found in non-ice-associated diatoms, which strongly suggests that IBPs are essential for survival in ice. The restricted occurrence also raises the question of how the IBP genes were acquired. Proteins with similar sequences and ice-binding activities are produced by ice-associated bacteria, and so it has previously been speculated that the genes were acquired by horizontal transfer (HGT) from bacteria. Here we report several new IBP sequences from three types of ice algae, which together with previously determined sequences reveal a phylogeny that is completely incongruent with algal phylogeny, and that can be most easily explained by HGT. HGT is also supported by the finding that the closest matches to the algal IBP genes are all bacterial genes and that the algal IBP genes lack introns. We also describe a highly freeze-tolerant bacterium from the bottom layer of Antarctic sea ice that produces an IBP with 47% amino acid identity to a diatom IBP from the same layer, demonstrating at least an opportunity for gene transfer. Together, these results suggest that the success of diatoms and other algae in sea ice can be at least partly attributed to their acquisition of prokaryotic IBP genes

    Status on the Michigan‐MIT ultra‐cold polarized hydrogen jet target

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    Progress on the Mark‐II ultra‐cold polarized atomic hydrogen gas Jet target for the experiments NEPTUN‐A and NEPTUN at UNK is presented. We describe the performance and the present status of different components of the jet.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87525/2/698_1.pd

    Factors related with the university degree selection in Spanish public university system. An structural equation model analysis

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11135-014-0008-9Students take into account different factors in their choice of university studies and college. Some are global, as the quality of the degree (ratio available places/firstchoice places in, cut-off grade, etc.), and others are subjective factors (e.g.: my friends are also taking this degree). In this work we present a partial multivariate model that takes into account the weight of the different variables shown by different works linked to this decision. We have studied three samples (n = 372 from the Universidad Pablo de Olavide; n = 2,244 from the Universitat Politécnica de Valencia, and n = 543 from the Universitat de Barcelona) from several degrees in the 2010 2011 and 2011 2012 academic years, all of them new students, coming from high school, and who had choosen these universities as first choice. The global effect shows that the structural model fits reasonably well in the three universities studied. Similarly, university and specialty models show different intensity effects, and we found that, in the case of Universitat Politécnica de Valencia (UPV) and Universitat de Barcelona (UB), they show higher intensity than in Universidad Pablo de Olavide (UPO). This makes us think that in most urban universities with a clear and regular offer of degrees (engineering in the case of UPV, and Health and Social Sciences in the case of UB), personal and social factors are more important than in the case of universities, as is the case of UPO, with an offer and dimension not yet completely defined.Guàrdia Olmos, J.; Peró Cebollero, M.; Hervás Jorge, A.; Capilla Lladró, R.; Soriano Jiménez, PP.; Porras Yañez, M. (2014). Factors related with the university degree selection in Spanish public university system. An structural equation model analysis. Quality and Quantity. 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