242 research outputs found

    Colored and Dissipative Continuous Spontaneous Localization model and Bounds from Matter-Wave Interferometry

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    Matter-wave interferometry is a direct test of the quantum superposition principle for massive systems, and of collapse models. Here we show that the bounds placed by matter-wave interferometry depend weakly on the details of the collapse mechanism. Specifically, we compute the bounds on the CSL model and its variants, provided by the the KDTL interferometry experiment of Arndt's group [Phys. Chem. Chem. Phys., 2013, 15, 14696-14700], which currently holds the record of largest mass in interferometry. We also show that the CSL family of models emerges naturally by considering a minimal set of assumptions. In particular, we construct the dynamical map for the colored and dissipative Continuous Spontaneous Localization (cdCSL) model, which reduces to the CSL model and variants in the appropriate limits. In addition, we discuss the measure of macroscopicity based on the cdCSL model.Comment: 9 pages, 5 figures; accepted for publication in Physics Letters A (2017

    Coherent scattering in non relativistic quantum mechanics

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    In this paper we give a pedagogical explanation of coherence effects in non relativistic scattering processes. Coherent scattering is important not only because it is a clear manifestation of the wave character of the interaction in these regimes, but also because it helps in increasing the cross section and thus the observable effects. We show under which conditions a particle scatters coherently on a multi-particle system. In a nutshell, in order to have coherent scattering, the incident particle has not to resolve the internal structure of the composite system. We show that the above condition is satisfied when the de Broglie length of the incident particle is much larger than the size of the system

    Social Innovation Policies with the Involvement of Social Economy Organizations. Survey Evidence from European Countries.

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    In this paper, we investigate significant social innovation policies (related to the concept of social investment) involving the role of Social Economy organizations, and we discuss some relevant national and regional social innovation experiences by relying upon the current national and international literature, reports and website information. The Working Paper is organized as follows. Section 1 is dedicated to briefly analyze the term “Social Innovation”. In Section 2, we investigate significant social innovation experiences involving the role of Social Economy organizations. We will carry out this analysis by reporting and rephrasing the answers to Question Q6 of the Template as given by the Academic Partners of the Innosi Project and to some email correspondence; and, whenever possible, by further analyzing in greater details some national social innovation experiences by relying upon the current national and international literature, reports and website information. In Section 3 we advance some concluding remarks

    End-to-End Speech Recognition and Disfluency Removal with Acoustic Language Model Pretraining

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    The SOTA in transcription of disfluent and conversational speech has in recent years favored two-stage models, with separate transcription and cleaning stages. We believe that previous attempts at end-to-end disfluency removal have fallen short because of the representational advantage that large-scale language model pretraining has given to lexical models. Until recently, the high dimensionality and limited availability of large audio datasets inhibited the development of large-scale self-supervised pretraining objectives for learning effective audio representations, giving a relative advantage to the two-stage approach, which utilises pretrained representations for lexical tokens. In light of recent successes in large scale audio pretraining, we revisit the performance comparison between two-stage and end-to-end model and find that audio based language models pretrained using weak self-supervised objectives match or exceed the performance of similarly trained two-stage models, and further, that the choice of pretraining objective substantially effects a model's ability to be adapted to the disfluency removal task

    A case of embolic stroke from atrial myxoma

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    Methylation Dynamics of RASSF1A and Its Impact on Cancer

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    5-methyl cytosine (5mC) is a key epigenetic mark entwined with gene expression and the specification of cellular phenotypes. Its distribution around gene promoters sets a barrier for transcriptional enhancers or inhibitor proteins binding to their target sequences. As a result, an additional level of regulation is added to the signals that organize the access to the chromatin and its structural components. The tumor suppressor gene RASSF1A is a microtubule-associated and multitasking scaffold protein communicating with the RAS pathway, estrogen receptor signaling, and Hippo pathway. RASSF1A action stimulates mitotic arrest, DNA repair and apoptosis, and controls the cell cycle and cell migration. De novo methylation of the RASSF1A promoter has received much attention due to its increased frequency in most cancer types. RASSF1A methylation is preceded by histones modifications and could represent an early molecular event in cell transformation. Accordingly, RASSF1A methylation is proposed as an epigenetic candidate marker in many cancer types, even though an inverse correlation of methylation and expression remains to be fully ascertained. Some findings indicate that the epigenetic abrogation of RASSF1A can promote the alternative expression of the putative oncogenic isoform RASSF1C. Understanding the complexity and significance of RASSF1A methylation is instrumental for a more accurate determination of its biological and clinical role. The review covers the molecular events implicated in RASSF1A methylation and gene silencing and provides a deeper view into the significance of the RASSF1A methylation patterns in a number of gastrointestinal cancer types

    Testing the foundation of quantum physics in space via Interferometric and non-interferometric experiments\ua0with mesoscopic nanoparticles

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    This perspective presents current and future possibilities offered by space technology for testing quantum mechanics, with a focus on mesoscopic superposition of nanoparticles and the potential of interferometric and non-interferometric experiments in space.Quantum technologies are opening novel avenues for applied and fundamental science at an impressive pace. In this perspective article, we focus on the promises coming from the combination of quantum technologies and space science to test the very foundations of quantum physics and, possibly, new physics. In particular, we survey the field of mesoscopic superpositions of nanoparticles and the potential of interferometric and non-interferometric experiments in space for the investigation of the superposition principle of quantum mechanics and the quantum-to-classical transition. We delve into the possibilities offered by the state-of-the-art of nanoparticle physics projected in the space environment and discuss the numerous challenges, and the corresponding potential advancements, that the space environment presents. In doing this, we also offer an ab-initio estimate of the potential of space-based interferometry with some of the largest systems ever considered and show that there is room for tests of quantum mechanics at an unprecedented level of detail

    The study of polyplex formation and stability by time-resolved fluorescence spectroscopy of SYBR Green I-stained DNA

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    Polyplexes are nanoparticles formed by the self-assembly of DNA/RNA and cationic polymers specifically designed to deliver exogenous genetic material to cells by a process called transfection. There is a general consensus that a subtle balance between sufficient extracellular protection and intracellular release of nucleic acids is a key factor for successful gene delivery. Therefore, there is a strong need to develop suitable tools and techniques for enabling the monitoring of the stability of polyplexes in the biological environment they face during transfection. In this work we propose time-resolved fluorescence spectroscopy in combination with SYBR Green I-DNA dye as a reliable tool for the in-depth characterization of the DNA/vector complexation state. As a proof of concept, we provide essential information on the assembly and disassembly of complexes formed between DNA and each of three cationic polymers, namely a novel promising chitosan-graft-branched polyethylenimine copolymer (Chi-g-bPEI), one of its building block 2 kDa bPEI and the gold standard transfectant 25 kDa bPEI. Our results highlight the higher information content provided by the time-resolved studies of SYBR Green I/DNA, as compared to conventional steady state measurements of ethidium bromide/DNA that enabled us to draw relationships among fluorescence lifetime, polyplex structural changes and transfection efficiency
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