1,989 research outputs found

    Note about a second "evidence" for a WIMP annual modulation

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    This note, with its five questions, is intended to contribute to a clarification about a claimed "evidence" by the DAMA group of an annual modulation of the counting rate of a Dark Matter NaI(Tl) detector as due to a neutralino (SUSY-LSP) Dark Matter candidate.Comment: LaTex, 3 pages, 2 figure

    Drosophila Importin-α2 Is Involved in Synapse, Axon and Muscle Development

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    Nuclear import is required for communication between the cytoplasm and the nucleus and to enact lasting changes in gene transcription following stimuli. Binding to an Importin-α molecule in the cytoplasm is often required to mediate nuclear entry of a signaling protein. As multiple isoforms of Importin-α exist, some may be responsible for the entry of distinct cargoes rather than general nuclear import. Indeed, in neuronal systems, Importin-α isoforms can mediate very specific processes such as axonal tiling and communication of an injury signal. To study nuclear import during development, we examined the expression and function of Importin-α2 in Drosophila melanogaster. We found that Importin-α2 was expressed in the nervous system where it was required for normal active zone density at the NMJ and axonal commissure formation in the central nervous system. Other aspects of synaptic morphology at the NMJ and the localization of other synaptic markers appeared normal in importin-α2 mutants. Importin-α2 also functioned in development of the body wall musculature. Mutants in importin-α2 exhibited errors in muscle patterning and organization that could be alleviated by restoring muscle expression of Importin-α2. Thus, Importin-α2 is needed for some processes in the development of both the nervous system and the larval musculature

    How the reliability of external competences shapes the modularization strategies of industrialized construction firms

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    Firms modularize as they move into industrialized construction. Prior research highlights the importance of their modularization strategies, arguing that firms can either build the competence for modularization internally or can source them externally. To understand what shapes a firm’s choice to use external competences in its modularization strategy, we studied three leading construction firms. In this multiple case study, Alpha, Beta and Gamma are leaders in Asian markets, using reinforced concrete solutions in high-rise industrialized construction. Where external competences are available, our analyses show the work firms do to make them reliable and that their choice to use external competences is shaped by their reliability. Alpha modularized in a context with little available external competences, so it built new competences in-house; Beta chose to use the externally available manufacturing and assembly competences, using standards, remote monitoring and control of product architectures to make them reliable for their use in modularization; Gamma had available competences in the external context and initially sought to use them, but reliability concerns led to it modularizing by acquiring the firms to bring these competences in-house. Our contribution is to show how ensuring the reliability of external competences shapes modularization strategies. Further, we have identified actions that firms can adopt to make external competences reliable through: (1) use of international standards, (2) quality control procedures, (3) control of product architectures, and 4) acquisition of external competences. We provide implications for practitioners and policy makers seeking to transition to industrialized construction; and discuss new areas for research

    The Role of Industry – University Collaboration in the Transformation of Construction

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    In this digest, we explore how industry and universities can and do work together to develop and increase the stock of knowledge and ideas, and in doing so, support the ongoing transformation of the construction sector and firms in it. We focus on connections between industry and the academic research community

    Seismic and mineralogical structures of the lower mantle from probabilistic tomography

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95386/1/jgrb17106.pd

    Addressing specialization and fragmentation: product platform development in construction consultancy firms

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    Construction product platforms provide the opportunity to improve productivity in construction projects while maintaining heterogeneity of output. The growing literature on construction product platforms describes how product suppliers develop product platforms either top-down or bottom-up, independently from project delivery. Through a single case study of a consultancy firm, this paper shows how specialist consultancy firms operating in the construction sector develop their own product platform on projects while iteratively developing and augmenting their delivery capabilities. Distinguishing between activity integration, coordination, and consolidation, the platform development process highlights how vertical and horizontal consolidation of capabilities within the engineering phase of delivery enables early resolution of both product and process specifications. This means that vertical coordination between engineering and manufacturing phases can be managed by a fully specified contract, rather than acquisition. The analysis of the case show how construction can be more closely aligned with the linear and sequential models found in manufacturing through clarifying and distinguishing the roles of engineering, manufacturing, finishing and sub-assembly

    Approximating Fractional Time Quantum Evolution

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    An algorithm is presented for approximating arbitrary powers of a black box unitary operation, Ut\mathcal{U}^t, where tt is a real number, and U\mathcal{U} is a black box implementing an unknown unitary. The complexity of this algorithm is calculated in terms of the number of calls to the black box, the errors in the approximation, and a certain `gap' parameter. For general U\mathcal{U} and large tt, one should apply U\mathcal{U} a total of ⌊t⌋\lfloor t \rfloor times followed by our procedure for approximating the fractional power Ut−⌊t⌋\mathcal{U}^{t-\lfloor t \rfloor}. An example is also given where for large integers tt this method is more efficient than direct application of tt copies of U\mathcal{U}. Further applications and related algorithms are also discussed.Comment: 13 pages, 2 figure
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