2,025 research outputs found

    Marginality and Problem Solving Effectiveness in Broadcast Search

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    We examine who the winners are in science problem solving contests characterized by open broadcast of problem information, self-selection of external solvers to discrete problems from the laboratories of large R&D intensive companies and blind review of solution submissions. Analyzing a unique dataset of 166 science challenges involving over 12,000 scientists revealed that technical and social marginality, being a source of different perspectives and heuristics, plays an important role in explaining individual success in problem solving. The provision of a winning solution was positively related to increasing distance between the solver’s field of technical expertise and the focal field of the problem. Female solvers – known to be in the “outer circle” of the scientific establishment - performed significantly better than men in developing successful solutions. Our findings contribute to the emerging literature on open and distributed innovation by demonstrating the value of openness, at least narrowly defined by disclosing problems, in removing barriers to entry to non-obvious individuals. We also contribute to the knowledge-based theory of the firm by showing the effectiveness of a market-mechanism to draw out knowledge from diverse external sources to solve internal problems

    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

    Pulsed pumping of a Bose-Einstein condensate

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    In this work, we examine a system for coherent transfer of atoms into a Bose-Einstein condensate. We utilize two spatially separate Bose-Einstein condensates in different hyperfine ground states held in the same dc magnetic trap. By means of a pulsed transfer of atoms, we are able to show a clear resonance in the timing of the transfer, both in temperature and number, from which we draw conclusions about the underlying physical process. The results are discussed in the context of the recently demonstrated pumped atom laser.Comment: 5 pages, 5 figures, published in Physical Review

    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
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