2,568 research outputs found

    Menander\u27s Samia: A New Translation

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    It is a commonplace thing nowadays for people to get home from work or school and settle down in front of the television to watch their favorite sitcom. There are numerous ones to choose from, but most of them involve a family or tightly knit group of friends who wander their way through seemingly everyday situations, dealing with them humorously, but in the same way you might expect someone you know to deal with them. We watch these shows, laugh at them, think about them, and sometimes even incorporate phrases and lines we hear from them into our everyday speech - but what we don\u27t realize is that in doing this we are actually participating in a tradition that is over two thousand years old. The Greek dramatic genre called New Comedy, which flourished in the 4th and 3rd centuries BCE, featured plots and characters similar to our modern-day sitcoms. Since the establishment near the end of the 6th century BCE of the annual dramatic festival in Athens, called the Dionysia, Athenians had been very involved with the dramatic productions of their day and were inclined to incorporate ideas from the plays they saw into their own lives. In a time without mass media, theater to the Greeks was the most exciting and influential form of art available, not to mention an important means of sharing ideas with large groups of people. Most of the tragedies presented at this time dealt, on the surface at least, with mythology, and as the scholars Gomme and Sandbach wrote, the Greeks were often ready to find in what we call their \u27mythology\u27 parallels for contemporary behavior. But the plays were also written in such a way that they often addressed current issues facing the Attic population

    Achieving peak brightness in an atom laser

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    In this paper we present experimental results and theory on the first continuous (long pulse) Raman atom laser. The brightness that can be achieved with this system is three orders of magnitude greater than has been previously demonstrated in any other continuously outcoupled atom laser. In addition, the energy linewidth of a continuous atom laser can be made arbitrarily narrow compared to the mean field energy of a trapped condensate. We analyze the flux and brightness of the atom laser with an analytic model that shows excellent agreement with experiment with no adjustable parameters.Comment: 4 pages, 4 black and white figures, submitted to Physical Revie

    A detector for continuous measurement of ultra-cold atoms in real time

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    We present the first detector capable of recording high-bandwidth real time atom number density measurements of a Bose Einstein condensate. Based on a two-color Mach-Zehnder interferometer, our detector has a response time that is six orders of magnitude faster than current detectors based on CCD cameras while still operating at the shot-noise limit. With this minimally destructive system it may be possible to implement feedback to stabilize a Bose-Einstein condensate or an atom laser.Comment: 3 pages, 3 figures, submitted to optics letter

    A quasi-monomode guided atom-laser from an all-optical Bose-Einstein condensate

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    We report the achievement of an optically guided and quasi-monomode atom laser, in all spin projection states (mF=m_F = -1, 0 and +1+1) of F=1 in Rubidium 87. The atom laser source is a Bose-Einstein condensate (BEC) in a crossed dipole trap, purified to any one spin projection state by a spin-distillation process applied during the evaporation to BEC. The atom laser is outcoupled by an inhomogenous magnetic field, applied along the waveguide axis. The mean excitation number in the transverse modes is =0.65±0.05 = 0.65 \pm 0.05 for mF=0m_F = 0 and =0.8±0.3 = 0.8 \pm 0.3 for the low field seeker mF=−1m_F = -1

    From multimode to monomode guided atom lasers: an entropic analysis

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    We have experimentally demonstrated a high level of control of the mode populations of guided atom lasers (GALs) by showing that the entropy per particle of an optically GAL, and the one of the trapped Bose Einstein condensate (BEC) from which it has been produced are the same. The BEC is prepared in a crossed beam optical dipole trap. We have achieved isentropic outcoupling for both magnetic and optical schemes. We can prepare GAL in a nearly pure monomode regime (85 % in the ground state). Furthermore, optical outcoupling enables the production of spinor guided atom lasers and opens the possibility to tailor their polarization

    Semiclassical limits to the linewidth of an atom laser

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    We investigate the linewidth of a quasi-continuous atom laser within a semiclassical framework. In the high flux regime, the lasing mode can exhibit a number of undesirable features such as density fluctuations. We show that the output therefore has a complicated structure that can be somewhat simplified using Raman outcoupling methods and energy-momentum selection rules. In the weak outcoupling limit, we find that the linewidth of an atom laser is instantaneously Fourier limited, but, due to the energy `chirp' associated with the draining of a condensate, the long-term linewidth of an atom laser is equivalent to the chemical potential of the condensate source. We show that correctly sweeping the outcoupling frequency can recover the Fourier-limited linewidth.Comment: 9 Figure

    Phase separation of the Potts model in que square lattice

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    When the two dimensional q-color Potts model in the square lattice is quenched at zero temperature with Glauber dynamics, the energy decreases in time following an Allen-Cahn power law, and the system converges to a phase with energy higher than the ground state energy after an arbitrary large time when q>4. At low but finite temperature, it cesses to obey the power-law regime and orders after a very long time, which increases with q, and before which it performs a domain growth process which tends to be slower as q increases. We briefly present and comment numerical results on the ordering at nonzero temperature.Comment: 3 pages, 1 figure, proceedings of the "International Workshop on Complex sytems", June 2006 in Santander (Spain

    Synthesis and Recognition Properties of Higher Order Tetrathiafulvalene (Ttf) Calix N Pyrroles (N=4-6)

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    Two new benzoTTF-annulated calix[n]pyrroles (n = 5 and 6) were synthesized via a one-step acid catalyzed condensation reaction and fully characterized via single crystallographic analyses. As compared to the known tetra-TTF annulated calix[4]pyrrole, which is also produced under the conditions of the condensation reaction, the expanded calix[n]pyrroles (n = 5 and 6) are characterized by a larger cavity size and a higher number of TTF units (albeit the same empirical formula). Analysis of the binding isotherms obtained from UV-Vis spectroscopic titrations carried out in CHCl3 in the presence of both anionic (Cl-, Br-, I-, CH3COO-, H2PO4-, and HSO4-) and neutral (1,3,5-trinitrobenzene (TNB) and 2,4,6-trinitrotoluene (TNT)) substrates revealed that as a general rule the calix[6]pyrrole derivative proved to be the most efficient molecular receptor for anions, while the calix[4]pyrrole congener proves most effective for the recognition of TNB and TNT. These findings are rationalized in terms of the number of electron rich TTF subunits and NH hydrogen bond donor groups within the series, as well as an ability to adopt conformations suitable for substrate recognition, and are supported by solid state structural analyses.National Science Foundation CHE 1057904, 0741973Robert A. Welch Foundation F-1018Danish Natural Science Research Council (FNU) 272-08-0047, 11-106744WCU (World Class University) program of Korea R32-2010-10217-0Villum FoundationChemistr

    Four cases on market orientation of value chains in agribusiness and fisheries

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    This working paper presents results from the project ‘Supra-company level determinants of degree of market orientation of value chains in agriculture and fisheries’, which is carried out in cooperation between MAPP – Centre for Research on Customer Relations in the Food Sector, Aarhus School of Business, Denmark, the Norwegian College of Fisheries Science, University of Tromsþ, Norway, and the Department of Marketing, University of Stirling, Scotland. It has benefited from grants from the Danish Social Science Research Council and from the Norwegian Research Council. The present working paper is the ‘long’ version of the empirical work in the first major phase of the project, where we study four examples of food value chains to get insight into their degree of market orientation and possible determinants. The insights gained here have been used in subsequent empirical work that is currently underwayMarket orientation;
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