8,732 research outputs found

    Dynamical Reduction Models: present status and future developments

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    We review the major achievements of the dynamical reduction program, showing why and how it provides a unified, consistent description of physical phenomena, from the microscopic quantum domain to the macroscopic classical one. We discuss the difficulties in generalizing the existing models in order to comprise also relativistic quantum field theories. We point out possible future lines of research, ranging from mathematical physics to phenomenology.Comment: 12 pages. Contribution to the Proceedings of the "Third International Workshop DICE2006", Castello di Piombino (Tuscany), September 11-15, 2006. Minor changes mad

    DNALinux Virtual Desktop Edition

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    The new version of DNALinux (VDE) is presented. DNALinux VDE is a departure from traditional distributions since it uses a virtual machine to bundle together the operating system and bioinformatics applications. The main advantage of this approach is that a virtualized environment doesn't affect a installed system. With a virtual machine a Linux system can be run under a Windows system, provided that the virtual machine player is installed. The included programs are listed and specifications to add more programs are explained. We believe that DNALinux could be used as a standardized virtual machine for learning, using, developing and testing bioinformatics applications

    Are collapse models testable with quantum oscillating systems? The case of neutrinos, kaons, chiral molecules

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    Collapse models provide a theoretical framework for understanding how classical world emerges from quantum mechanics. Their dynamics preserves (practically) quantum linearity for microscopic systems, while it becomes strongly nonlinear when moving towards macroscopic scale. The conventional approach to test collapse models is to create spatial superpositions of mesoscopic systems and then examine the loss of interference, while environmental noises are engineered carefully. Here we investigate a different approach: We study systems that naturally oscillate --creating quantum superpositions-- and thus represent a natural case-study for testing quantum linearity: neutrinos, neutral mesons, and chiral molecules. We will show how spontaneous collapses affect their oscillatory behavior, and will compare them with environmental decoherence effects. We will show that, contrary to what previously predicted, collapse models cannot be tested with neutrinos. The effect is stronger for neutral mesons, but still beyond experimental reach. Instead, chiral molecules can offer promising candidates for testing collapse models.Comment: accepted by NATURE Scientific Reports, 12 pages, 1 figures, 2 table

    Current marketing practices and market orientation in the context of an emerging economy: the case of Uruguay

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    This research explores the link between contemporary marketing practices, market orientation and business performance in Uruguay, an emergent country that has recovered from an economic crisis. These approaches seem to be related, but there is no existing evidence to confirm this impression. Lessons can be learned from understanding how effective is the adoption of marketing practices under a crisis scenario. Using data from interviews with 143 micro and small enterprises’ managers, we identify three clusters dependant on the combination of marketing practices: a multi-marketing cluster, a medium-level relationship marketing cluster and a transactional cluster. A model relating market orientation components and various performance measures is tested for the three clusters, showing that the multi-marketing and transactional clusters are more effective in translating efforts and resources into business outcomes.Contemporary marketing practices, Market orientation, Performance, Clusters, Structural equation modeling, Uruguay

    Collapse models with non-white noises

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    We set up a general formalism for models of spontaneous wave function collapse with dynamics represented by a stochastic differential equation driven by general Gaussian noises, not necessarily white in time. In particular, we show that the non-Schrodinger terms of the equation induce the collapse of the wave function to one of the common eigenstates of the collapsing operators, and that the collapse occurs with the correct quantum probabilities. We also develop a perturbation expansion of the solution of the equation with respect to the parameter which sets the strength of the collapse process; such an approximation allows one to compute the leading order terms for the deviations of the predictions of collapse models with respect to those of standard quantum mechanics. This analysis shows that to leading order, the ``imaginary'' noise trick can be used for non-white Gaussian noise.Comment: Latex, 20 pages;references added and minor revisions; published as J. Phys. A: Math. Theor. {\bf 40} (2007) 15083-1509

    Marketing practices and performance in a post-crisis scenario

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    This research explores the link between contemporary marketing practices, market orientation and business performance in Uruguay, an emergent country that has recovered from an economic crisis. These approaches seem to be related, but there is no existing evidence to confirm this impression. Lessons can be learned from understanding how effective is the adoption of marketing practices under a crisis scenario. Using data from interviews with 143 micro and small enterprises’ managers, we identify three clusters dependant on the combination of marketing practices: a multi-marketing cluster, a medium-level relationship marketing cluster and a transactional cluster. A model relating market orientation components and various performance measures is tested for the three clusters, showing that the multi-marketing and transactional clusters are more effective in translating efforts and resources into business outcomes

    Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy

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    A simple, reliable method for preparation of bulk Cr tips for Scanning Tunneling Microscopy (STM) is proposed and its potentialities in performing high-quality and high-resolution STM and Spin Polarized-STM (SP-STM) are investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to what happens with conventional W tips, rest atoms of the Si(111)-7x7 reconstruction can be routinely observed, probably due to a different electronic structure of the tip apex. SP-STM measurements of the Cr(001) surface showing magnetic contrast are reported. Our results reveal that the peculiar properties of these tips can be suited in a number of STM experimental situations
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