9,155 research outputs found

    Detecting Lensing-Induced Diffraction in Astrophysical Gravitational Waves

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    Gravitational waves emitted from compact binary coalescence can be subject to wave diffraction if they are gravitationally lensed by an intervening mass clump whose Schwarzschild timescale matches the wave period. Waves in the ground-based frequency band f10f\sim 10--10310^3\,Hz are sensitive to clumps with masses ME102M_E \sim 10^2--103M10^3\,M_\odot enclosed within the impact parameter. These can be the central parts of low mass ML103M_L \sim 10^3--106M10^6\,M_\odot dark matter halos, which are predicted in Cold Dark Matter scenarios but are challenging to observe. Neglecting finely-tuned impact parameters, we focus on lenses aligned generally on the Einstein scale for which multiple lensed images may not form in the case of an extended lens. In this case, diffraction induces amplitude and phase modulations whose sizes 10%\sim 10\%--20%20\% are small enough so that standard matched filtering with unlensed waveforms do not degrade, but are still detectable for events with high signal-to-noise ratio. We develop and test an agnostic detection method based on dynamic programming, which does not require a detailed model of the lensed waveforms. For pseudo-Jaffe lenses aligned up to the Einstein radius, we demonstrate that a pair of fully upgraded aLIGO/Virgo detectors can extract diffraction imprints from binary black hole mergers out to zs0.2z_s \sim 0.2--0.30.3. The prospect will improve dramatically for a third-generation detector for which binary black hole mergers out to zs2z_s \sim 2--44 will all become valuable sources.Comment: 14 pages including references; 8 figures; comments are welcom

    The Business Value of CRM Technology: From the Perspective of Organizational Ambidexterity

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    In this paper we report a case study on how firms realize the business value of CRM by developing CRM-enabled ambidexterity to simultaneously pursue stability and develop adaptability. Results show that as the focal firm used CRM as a platform for standardizing operations and building routines, the top management team (TMT) and the operation team worked together to reflexively monitor the status of CRM-enabled capabilities and the usage of CRM. Such reflexive monitoring led to proactive changes in CRM and CRM usage in response to market changes and market needs, ensuring adaptability. In this way CRM enabled organizational ambidexterity through mechanisms of capabilities building and reflexive monitoring. By examining the previously unexplored relationship between CRM use and organizational ambidexterity, this study contributes to literature in both ambidexterity and CRM business value

    Cosmic-ray-mediated Formation of Benzene on the Surface of Saturn's Moon Titan

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    The aromatic benzene molecule (C_6H_6)—a central building block of polycyclic aromatic hydrocarbon molecules—is of crucial importance for the understanding of the organic chemistry of Saturn's largest moon, Titan. Here, we show via laboratory experiments and electronic structure calculations that the benzene molecule can be formed on Titan's surface in situ via non-equilibrium chemistry by cosmic-ray processing of low-temperature acetylene (C_2H_2) ices. The actual yield of benzene depends strongly on the surface coverage. We suggest that the cosmic-ray-mediated chemistry on Titan's surface could be the dominant source of benzene, i.e., a factor of at least two orders of magnitude higher compared to previously modeled precipitation rates, in those regions of the surface which have a high surface coverage of acetylene

    PR-Set7 is Degraded in a Conditional Cul4A Transgenic Mouse Model of Lung Cancer.

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    BackgroundMaintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer. PR-Set7 (also known as Set8) is a cell cycle regulated enzyme that catalyses monomethylation of histone 4 at Lys20 (H4K20me1) to promote chromosome condensation and prevent DNA damage. Recent studies show that CRL4CDT2-mediated ubiquitylation of PR-Set7 leads to its degradation during S phase and after DNA damage. This might occur to ensure appropriate changes in chromosome structure during the cell cycle or to preserve genome integrity after DNA damage.MethodsWe developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A. We have therefore used a mouse model to demonstrate for the first time that Cul4A is oncogenic in vivo. With this model, staining of PR-Set7 in the preneoplastic and tumor lesions in AdenoCre-induced mouse lungs was performed. Meanwhile we identified higher protein level changes of γ-tubulin and pericentrin by IHC.ResultsThe level of PR-Set7 down-regulated in the preneoplastic and adenocarcinomous lesions following over-expression of Cul4A. We also identified higher levels of the proteins pericentrin and γ-tubulin in Cul4A mouse lungs induced by AdenoCre.ConclusionsPR-Set7 is a direct target of Cul4A for degradation and involved in the formation of lung tumors in the conditional Cul4A transgenic mouse model

    catena-Poly[[[bis­[4-(1H-1,3,7,8-tetra­azacyclo­penta­[l]phenanthren-2-yl)phenol-κ2 N 7,N 8]manganese(II)]-μ-naphthalene-1,4-dicarboxyl­ato-κ2 O 1:O 4] naphthalene-1,4-dicarboxylic acid hemisolvate monohydrate]

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    The 1,4-dicarboxyl­ate dianions in the title compound, [Mn(C12H6O4)(C19H12N4O)2]·0.5C12H8O4·H2O, bond to two 4-(1H-1,3,7,8-tetra­azacyclo­penta­[l]phenanthren-2-yl)phenol-chelated Mn atoms to form a chain that features the metal atom in an octa­hedral coordination geometry. Adjacent chains inter­act with the uncoordinated water mol­ecules to form a three-dimensional network. The naphthalene-1,4-dicarboxylic acid solvent mol­ecule, which is disordered about a centre of inversion, occupies the space within the network but is not bonded to the network. One NH group is disordered equally over two positions

    Capacity of Cooperative Vehicular Networks with Infrastructure Support: Multiuser Case

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    © 1967-2012 IEEE. Capacity of vehicular networks with infrastructure support is both an interesting and challenging problem as the capacity is determined by the interplay of multiple factors including vehicle-to-infrastructure (V2I) communications, vehicle-to-vehicle (V2V) communications, density and mobility of vehicles, and cooperation among vehicles and infrastructure. In this paper, we consider a typical delay-tolerant application scenario with a subset of vehicles, termed Vehicles of Interest (VoIs), having download requests. Each VoI downloads a distinct large-size file from the Internet and other vehicles without download requests assist the delivery of the files to the VoIs. A cooperative communication strategy is proposed that explores the combined use of V2I communications, V2V communications, mobility of vehicles and cooperation among vehicles and infrastructure to improve the capacity of vehicular networks. An analytical framework is developed to model the data dissemination process using this strategy, and a closed-form expression of the achievable capacity is obtained, which reveals the relationship between the capacity and its major performance-impacting parameters such as inter-infrastructure distance, radio ranges of infrastructure and vehicles, sensing range of vehicles, transmission rates of V2I and V2V communications, vehicular density, and proportion of VoIs. Numerical result shows that the proposed cooperative communication strategy significantly boosts the capacity of vehicular networks, especially when the proportion of VoIs is low. Our results provide guidance on the optimum deployment of a vehicular network infrastructure and the design of a cooperative communication strategy to improve the capacity
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