1,186 research outputs found

    Lorentz-Invariant "Elements of Reality" and the Question of Joint Measurability of Commuting Observables

    Full text link
    It is shown that the joint measurements of some physical variables corresponding to commuting operators performed on pre- and post-selected quantum systems invariably disturb each other. The significance of this result for recent proofs of the impossibility of realistic Lorentz invariant interpretation of quantum theory (without assumption of locality) is discussed.Comment: 15 page

    Could Only Fermions Be Elementary?

    Full text link
    In standard Poincare and anti de Sitter SO(2,3) invariant theories, antiparticles are related to negative energy solutions of covariant equations while independent positive energy unitary irreducible representations (UIRs) of the symmetry group are used for describing both a particle and its antiparticle. Such an approach cannot be applied in de Sitter SO(1,4) invariant theory. We argue that it would be more natural to require that (*) one UIR should describe a particle and its antiparticle simultaneously. This would automatically explain the existence of antiparticles and show that a particle and its antiparticle are different states of the same object. If (*) is adopted then among the above groups only the SO(1,4) one can be a candidate for constructing elementary particle theory. It is shown that UIRs of the SO(1,4) group can be interpreted in the framework of (*) and cannot be interpreted in the standard way. By quantizing such UIRs and requiring that the energy should be positive in the Poincare approximation, we conclude that i) elementary particles can be only fermions. It is also shown that ii) C invariance is not exact even in the free massive theory and iii) elementary particles cannot be neutral. This gives a natural explanation of the fact that all observed neutral states are bosons.Comment: The paper is considerably revised and the following results are added: in the SO(1,4) invariant theory i) the C invariance is not exact even for free massive particles; ii) neutral particles cannot be elementar

    HeLayers: A Tile Tensors Framework for Large Neural Networks on Encrypted Data

    Full text link
    Privacy-preserving solutions enable companies to offload confidential data to third-party services while fulfilling their government regulations. To accomplish this, they leverage various cryptographic techniques such as Homomorphic Encryption (HE), which allows performing computation on encrypted data. Most HE schemes work in a SIMD fashion, and the data packing method can dramatically affect the running time and memory costs. Finding a packing method that leads to an optimal performant implementation is a hard task. We present a simple and intuitive framework that abstracts the packing decision for the user. We explain its underlying data structures and optimizer, and propose a novel algorithm for performing 2D convolution operations. We used this framework to implement an HE-friendly version of AlexNet, which runs in three minutes, several orders of magnitude faster than other state-of-the-art solutions that only use HE.Comment: 17 pages, 7 figure

    Deep inelastic scattering and final state interaction in an exactly solvable relativistic model

    Get PDF
    In the theory of deep inelastic scattering (DIS) the final state interaction (FSI) between the struck quark and the remnants of the target is usually assumed to be negligible in the Bjorken limit. This assumption, still awaiting a full validation within nonperturbative QCD, is investigated in a model composed by two relativistic particles, interacting via a relativistic harmonic oscillator potential, within light-cone hamiltonian dynamics. An electromagnetic current operator whose matrix elements behave properly under Poincar\'e transformations is adopted. It is shown that: i) the parton model is recovered, once the standard parton model assumptions are adopted; and ii) when relativistic, interacting eigenfunctions are exactly taken into account for both the initial and final states, the values of the structure functions, averaged over small, but finite intervals of the Bjorken variable xx, coincide with the results of the parton model in the Bjorken limit.Comment: 26 pages, to appear in Phys. Rev. C (May 1998

    Effect of fat composition in enteral nutrition for Crohn's disease in adults: A systematic review

    Get PDF
    Background & aims: The role of enteral nutrition (EN) fat composition in regulating inflammation in Crohn's disease (CD) is not clear. There is, moreover, insufficient evidence to guide the choice of EN in CD with any confidence. We have reanalysed the findings of previous studies in a systematic review focussing on the relationship between EN fat content and remission rates (RR). Methods: A systematic search with no language restriction was undertaken in Medline and Embase databases supplemented by a manual search in the reference lists of identified studies. The selection criteria were: clinical trial, exclusive EN, adults and CD. Data on the type of EN, its fat composition, achieved RR, and study design were extracted. An established assessment tool was used to assess the quality of the studies. Results: A total of 29 clinical trials are included in this review. The quality of the studies was highly variable. No fewer than 27 formulations of enteral feed were identified including 4 elemental and 23 non-elemental preparations. There was a positive correlation between the total n-6 fatty acid content and response rates, which was significant when expressed as the ratio between n-6 and n-3 fatty acids (r = 0.378, p = 0.018). A non-significant positive trend was founded (r = 0.072; p = 0.643) between medium chain triglycerides (MCT) delivery as a percentage of the total energy provision and RR. While a non-significant negative trend was reported for the delivery of monounsaturated fatty acids (MUFA) (r = −0.23, p = 0.13). A qualitative advantage to regimens based on safflower oil suggest that optimised therapeutic approaches are within reach

    Mouse Acetylcholinesterase Enhances Neurite Outgrowth of Rat R28 Cells Through Interaction With Laminin-1

    Get PDF
    The enzyme acetylcholinesterase (AChE) terminates synaptic transmission at cholinergic synapses by hydrolyzing the neurotransmitter acetylcholine, but can also exert ‘non-classical’, morpho-regulatory effects on developing neurons such as stimulation of neurite outgrowth. Here, we investigated the role of AChE binding to laminin-1 on the regulation of neurite outgrowth by using cell culture, immunocytochemistry, and molecular biological approaches. To explore the role of AChE, we examined fiber growth of cells overexpressing different forms of AChE, and/or during their growth on laminin-1. A significant increase of neuritic growth as compared with controls was observed for neurons over-expressing AChE. Accordingly, addition of globular AChE to the medium increased total length of neurites. Co-transfection with PRIMA, a membrane anchor of AChE, led to an increase in fiber length similar to AChE overexpressing cells. Transfection with an AChE mutant that leads to the retention of AChE within cells had no stimulatory effect on neurite length. Noticeably, the longest neurites were produced by neurons overexpressing AChE and growing on laminin-1, suggesting that the AChE/laminin interaction is involved in regulating neurite outgrowth. Our findings demonstrate that binding of AChE to laminin-1 alters AChE activity and leads to increased neurite growth in culture. A possible mechanism of the AChE effect on neurite outgrowth is proposed due to the interaction of AChE with laminin-1

    Fascin overexpression promotes neoplastic progression in oral squamous cell carcinoma

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Fascin is a globular actin cross-linking protein, which plays a major role in forming parallel actin bundles in cell protrusions and is found to be associated with tumor cell invasion and metastasis in various type of cancers including oral squamous cell carcinoma (OSCC). Previously, we have demonstrated that fascin regulates actin polymerization and thereby promotes cell motility in K8-depleted OSCC cells. In the present study we have investigated the role of fascin in tumor progression of OSCC.</p> <p>Methods</p> <p>To understand the role of fascin in OSCC development and/or progression, fascin was overexpressed along with vector control in OSCC derived cells AW13516. The phenotype was studied using wound healing, Boyden chamber, cell adhesion, Hanging drop, soft agar and tumorigenicity assays. Further, fascin expression was examined in human OSCC samples (N = 131) using immunohistochemistry and level of its expression was correlated with clinico-pathological parameters of the patients.</p> <p>Results</p> <p>Fascin overexpression in OSCC derived cells led to significant increase in cell migration, cell invasion and MMP-2 activity. In addition these cells demonstrated increased levels of phosphorylated AKT, ERK1/2 and JNK1/2. Our in vitro results were consistent with correlative studies of fascin expression with the clinico-pathological parameters of the OSCC patients. Fascin expression in OSCC showed statistically significant correlation with increased tumor stage (<it>P </it>= 0.041), increased lymph node metastasis (<it>P </it>= 0.001), less differentiation (<it>P </it>= 0.005), increased recurrence (<it>P </it>= 0.038) and shorter survival (<it>P </it>= 0.004) of the patients.</p> <p>Conclusion</p> <p>In conclusion, our results indicate that fascin promotes tumor progression and activates AKT and MAPK pathways in OSCC-derived cells. Further, our correlative studies of fascin expression in OSCC with clinico-pathological parameters of the patients indicate that fascin may prove to be useful in prognostication and treatment of OSCC.</p

    Tra il foglio vuoto e lo schermo. Type e token alla prova dell’arte post-mediale

    Get PDF
    What kind of entities are works of art from an ontological point of view? This question has become canonical in the framework of analytic philosophy. One way of answering the puzzle seemed to be conclusive. It is the hypothesis that all, or the majority of artworks can be identified with types embedded into tokens. To begin with, I will survey how the type-token distinction transitioned from semiotics to ontology. Secondly, I will consider how some contemporary art forms contributed to questioning this approach to the ontology of artworks. Lastly, I will suggest how the nature of types and tokens should be reassessed in order to properly describe artworks in their historical and socially construed nature
    corecore