2,458 research outputs found

    The discrimination problem for two ground states or two thermal states of the quantum Ising model

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    We address the one-dimensional quantum Ising model as an example of system exhibiting criticality and study in some details the discrimination problem for pairs of states corresponding to different values of the coupling constant. We evaluate the error probability for single-copy discrimination, the Chernoff bound for nn-copy discrimination in the asymptotic limit, and the Chernoff metric for the discrimination of infinitesimally close states. We point out scaling properties of the above quantities, and derive the external field optimizing state discrimination for short chains as well as in the thermodynamical limit, thus assessing criticality as a resource for quantum discrimination in many-body systems.Comment: revised version, title changed, 4 fig

    Effect of noise and enhancement of nonlocality in on/off photodetection

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    Nonlocality of two-mode states of light is addressed by means of CHSH inequality based on displaced on/off photodetection. Effects due to non-unit quantum efficiency and nonzero dark counts are taken into account. Nonlocality of both balanced and unbalanced superpositions of few photon-number states, as well as that of multiphoton twin beams, is investigated. We find that unbalanced superpositions show larger nonlocality than balanced one when noise affects the photodetection process. De-Gaussification by means of (inconclusive) photon subtraction is shown to enhance nonlocality of twin beams in the low energy regime. We also show that when the measurement is described by a POVM, rather than a set of projectors, the maximum achievable value of the Bell parameter in the CHSH inequality is decreased, and is no longer given by the Cirel'son bound.Comment: 21 Figure

    Short communication: Endoplasmic reticulum stress gene network expression in bovine mammary tissue during the lactation cycle.

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    Abstract The endoplasmic reticulum (ER) has a crucial role in cellular metabolism. Recent studies in nonruminants discovered that components of the ER stress pathway, induced during the unfolded protein response, play critical roles in regulating lipogenesis. The bovine mammary gland faces extreme metabolic stress at the onset of lactation due primarily to the increase in flux through pathways associated with milk fat and protein synthesis. Our objective was to study, via quantitative real-time PCR, the expression of the ER stress pathway components P58IPK , PERK , XBP1 , ATF4 , ATF3 , ATF6 , CHOP , MBTPS1 , GRP94 , and BiP in mammary tissue (n=7 cows × 5 time points) collected at −15, 1, 15, 60, and 240 d relative to parturition. Expression of P58IPK and ATF4 increased to a peak at d 60, followed by a decrease by d 240 postpartum. Despite the decrease in expression by 240 d, P58IPK remained higher than prepartal levels (d −15). Expression patterns of ATF3 and CHOP were similar and peaked at d 15, followed by a decrease through d 240, at which point CHOP expression was still greater than prepartal levels. The sharp increase in milk production postpartum (d 15) as well as apoptosis during late lactation (240 d) may have induced a pseudo unfolded protein response state. This is supported by the similar expression patterns of P58IPK and PERK . In the context of lactation, however, transcriptional changes in the ER stress pathway at different stages of the lactation cycle are a normal aspect of the tissue's adaptation to the changing physiological state

    Very High Cycle Corrosion Fatigue Study of the Collapsed Polcevera Bridge, Italy

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    A possible scenario is proposed to put into evidence how the combined effect of fatigue at very high number of cycles and corrosion could have been responsible for the failure of one of the strands and the subsequent collapse of the so-called balanced system of the Polcevera Bridge designed by Morandi. The analysis accounts for an actual estimation of the heavy-lorry traffic and load spectrum, as well as for the European Standards prescription for the fatigue damage accumulation assessment. In addition, the effective construction phases of the viaduct are considered. The structural analysis is carried out by means of analytical models, in order to simplify the structure complexity without prejudice to the description of the most relevant aspects of the structural behavior. The main purpose is to warn the scientific community and the public administrations that the combined effects of low-amplitude fatigue and corrosion can be dangerously underestimated, and that the existing assets of 20th century bridges deserve special attention in this respect

    Optical coherence tomography and optical coherence tomography angiography in uveitis : a review

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    Optical coherence tomography (OCT) has dramatically changed the understanding and management of uveitis and other ocular conditions. Currently, OCT angiography (OCTA) combines structural information with the visualization of blood flow within the imaged area. The aim of this review is to present the basic principles of OCT and OCTA interpretation and to investigate the role of these imaging techniques in the diagnosis and management of uveitis. Common complications of intraocular inflammation such as macular oedema and inflammatory choroidal neovascularization are often diagnosed and followed with OCT/OCTA scans. However, uveitis specialists can obtain much more information from tomographic scans. This review provides a comprehensive description of typical OCT/OCTA findings characterizing different ocular structures in uveitis, proceeding from the cornea to the choroid. A careful interpretation of OCT/OCTA images can help in the differential diagnosis, the prediction of clinical outcomes, and the follow-up of patients with uveitis

    Disease of the Year : Differential Diagnosis of Uveitic Macular Edema

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    Uveitic cystoid macular edema (UME) is an important cause of visual morbidity among patients with both infectious and non-infectious uveitis. UME may be associated in more than 30% cases of active uveitis. However, even patients with minimal features of intraocular inflammation may develop recurrent or chronic UME. Therefore, the evaluation and management of UME in patients with uveitis may be challenging. A number of vitreoretinal pathologies may result in UME and accumulation of fluid in the intra- or subretinal space. These need to be carefully distinguished from each other so that appropriate management can be initiated. All types of uveitis, including anterior uveitis (where the primary site of inflammation is not in the posterior segment) can present with UME. Other conditions such as diabetes, and surgery, can present with macular edema. This index review highlights various differential diagnoses of UME and provides illustrative case examples with multimodal imaging evaluation

    Zero Emission Geothermal Flash Power Plant

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    The successful exploitation of geothermal energy for power production relies on the availability of nearly zero emission and efficient technologies. Two zero emission flash plant layouts, with full reinjection of the geothermal fluid (non-condensable gas included), are considered. This paper focusses on the CO2issue, and therefore only the carbon dioxide is considered as non-condensable gas present in the geothermal fluid; the CO2 flow is separated, compressed, and reinjected with the geothermal fluid. Both the reservoir and the power plant are simulated. A first scheme of plant presents a conventional layout in which the CO2is separated and compressed after the condenser. The second scheme presents a plant layout that allows the separation of the CO2at higher pressure with respect to the conventional layout, thus reducing the requested power consumption. The conventional plant scheme performs always better at higher temperature and at lower concentration of CO2. The new layout results better for low temperature and higher gas content
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