3,063 research outputs found

    Bell's inequality violation due to misidentification of spatially non stationary random processes

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    Correlations for the Bell gedankenexperiment are constructed using probabilities given by quantum mechanics, and nonlocal information. They satisfy Bell's inequality and exhibit spatial non stationarity in angle. Correlations for three successive local spin measurements on one particle are computed as well. These correlations also exhibit non stationarity, and satisfy the Bell inequality. In both cases, the mistaken assumption that the underlying process is wide-sense-stationary in angle results in violation of Bell's inequality. These results directly challenge the wide-spread belief that violation of Bell's inequality is a decisive test for nonlocality.Comment: 15 pages, 3 figure

    Pseudogap in high-temperature superconductors from realistic Fr\"ohlich and Coulomb interactions

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    It has been recently shown that the competition between unscreened Coulomb and Fr\"{o}hlich electron-phonon interactions can be described in terms of a short-range spin exchange JpJ_p and an effective on-site interaction U~\tilde{U} in the framework of the polaronic tt-JpJ_p-U~\tilde{U} model. This model, that provides an explanation for high temperature superconductivity in terms of Bose-Einstein condensation (BEC) of small and light bipolarons, is now studied as a charged Bose-Fermi mixture. Within this approximation, we show that a gap between bipolaron and unpaired polaron bands results in a strong suppression of low-temperature spin susceptibility, specific heat and tunneling conductance, signaling the presence of normal state pseudogap without any assumptions on preexisting orders or broken symmetries in the normal state of the model.Comment: 5 pages, 5 figure

    3D Laparoscopy. A potential cutting edge in minimal invasive digestive surgery

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    Laparoscopic surgery has changed surgical landscape, providing reduced surgical trauma, shorter hospital stays, less postoperative pain and better outcomes than open surgery. Since its first development in the 90’s, 3D technology applied to laparoscopic surgery has had several technical improvements and now it represents, together with high definition technology, the best option in minimal invasive digestive surgery, providing shorter operative times and lower blood loss, making easier to perform surgical tasks both for trainees than for skilled surgeons. It remains a little bit more expensive than standard 2D laparoscopic devices but even cheaper than robotic equipment

    Inhibition of phosphoinositide 3-kinase/protein kinase B signaling hampers the vasopressin-dependent stimulation of myogenic differentiation

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    Arginine-vasopressin (AVP) promotes muscle differentiation, hypertrophy, and regeneration through the combined activation of the calcineurin and Calcium/Calmodulin-dependent Protein Kinase (CaMK) pathways. The AVP system is impaired in several neuromuscular diseases, suggesting that AVP may act as a physiological factor in skeletal muscle. Since the Phosphoinositide 3-kinases/Protein Kinase B/mammalian Target Of Rapamycin (PI3K/Akt/mTOR) signaling plays a significant role in regulating muscle mass, we evaluated its role in the AVP myogenic effect. In L6 cells AKT1 expression was knocked down, and the AVP-dependent expression of mTOR and Forkhead box O3 (FoxO) was analyzed by Western blotting. The effect of the PI3K inhibitor LY294002 was evaluated by cellular and molecular techniques. Akt knockdown hampered the AVP-dependent mTOR expression while increased the levels of FoxO transcription factor. LY294002 treatment inhibited the AVP-dependent expression of Myocyte Enhancer Factor-2 (MEF2) and myogenin and prevented the nuclear translocation of MEF2. LY294002 also repressed the AVP-dependent nuclear export of histone deacetylase 4 (HDAC4) interfering with the formation of multifactorial complexes on the myogenin promoter. We demonstrate that the PI3K/Akt pathway is essential for the full myogenic effect of AVP and that, by targeting this pathway, one may highlight novel strategies to counteract muscle wasting in aging or neuromuscular disorders

    The role of digital technologies for the LCA empowerment towards circular economy goals: a scenario analysis for the agri-food system

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    Purpose This paper aims to develop a scenario analysis on the experts' perceptions of benefits and barriers related to adopting digital technologies for the life cycle assessment (LCA) to catalyse a circular economy transition in the agri-food system. Methods A literature review was performed to identify LCA's digital technologies that can be implemented within the agri-food system. Furthermore, an in-depth interview with a panel of senior researchers was conducted to establish a set of items and assess the perceived benefits and barriers associated with an "empowered LCA", i.e. a future-oriented LCA based on digital technologies. To this end, a two-stage exploratory factor analysis relying on the principal component analysis technique was carried out to refine the set of items. Finally, a covariance-based structural equation model was performed, built on a confirmatory factor analysis, to test the measurement model. Results and discussion The study's findings provide five constructs to explore the potential benefits and barriers related to adopting a digital technologies-based LCA (empowered LCA) for a circular economy transition in the agri-food system. More specifically, the benefits can be assessed using the following constructs: "benefits for the data collection and analysis", "benefits for the LCA analysts", "benefits for the management" and "benefits for traceability". In addition, the barriers have been evaluated using a single construct labelled "general barriers". Conclusions The study highlights the relevance of digital technologies for a circular economy transition to develop a more reliable LCA, enhancing legislative compliance and supporting the traceability processes in the agri-food system. The associated implications for LCA experts, agri-food managers and policymakers are presented. Furthermore, limitations and future research directions are also discussed

    Laparoscopic Treatment of Bouveret's Syndrome Presenting as Acute Pancreatitis

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    Gastric outlet obstruction as a result of gallstone (Bouveret's syndrome) is a rare but serious complication of cholelithiasis. Although patients present with persistent vomiting, colicky epigastric pain and dehydration, the clinical features of the Bouveret's syndrome are not pathognomonic. Due to its rarity, the diagnosis and treatment represent a challenge for the surgeon. In most of the reported cases, the diagnosis was made at the time of laparotomy. We report an unusual clinical presentation of Bouveret's syndrome with mild acute pancreatitis that was treated laparoscopically. To our knowledge, this is the first described case. Cause, clinical presentation, methods of diagnosis, and options for management of Bouveret's syndrome are also discussed

    Superlight small bipolarons from realistic long-range Coulomb and Fr\"ohlich interactions

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    We report analytical and numerical results on the two-particle states of the polaronic t-Jp model derived recently with realistic Coulomb and electron-phonon (Frohlich) interactions in doped polar insulators. Eigenstates and eigenvalues are calculated for two different geometries. Our results show that the ground state is a bipolaronic singlet, made up of two polarons. The bipolaron size increases with increasing ratio of the polaron hopping integral t to the exchange interaction Jp but remains small compared to the system size in the whole range 0<t/Jp<1. Furthermore, the model exhibits a phase transition to a superconducting state with a critical temperature well in excess of 100K. In the range t/Jp<1, there are distinct charge and spin gaps opening in the density of states, specific heat, and magnetic susceptibility well above Tc.Comment: Calculation section and discussion of gap have been updated. Revised calculations now enhance the predicted T_c in our model to over 200 K at large hoppin

    Seismic behaviour of geotechnical structures

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    This paper deals with some fundamental considerations regarding the behaviour of geotechnical structures under seismic loading. First a complete definition of the earthquake disaster risk is provided, followed by the importance of performing site-specific hazard analysis. Then some suggestions are provided in regard to adequate assessment of soil parameters, a crucial point to properly analyze the seismic behaviour of geotechnical structures. The core of the paper is centered on a critical review of the analysis methods available for studying geotechnical structures under seismic loadings. All of the available methods can be classified into three main classes, including the pseudo-static, pseudo-dynamic and dynamic approaches, each of which is reviewed for applicability. A more advanced analysis procedure, suitable for a so-called performance-based design approach, is also described in the paper. Finally, the seismic behaviour of the El Infiernillo Dam was investigated. It was shown that coupled elastoplastic dynamic analyses disclose some of the important features of dam behaviour under seismic loading, confirmed by comparing analytical computation and experimental measurements on the dam body during and after a past earthquake
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