429 research outputs found

    Entanglement distance for arbitrary M -qudit hybrid systems

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    This is the final version. Available from the American Physical Society via the DOI in this recordThe achievement of quantum supremacy boosted the need for a robust medium of quantum information. In this task, higher-dimensional qudits show remarkable noise tolerance and enhanced security for quantum key distribution applications. However, to exploit the advantages of such states, we need a thorough characterisation of their entanglement. Here, we propose a measure of entanglement which can be computed either for pure and mixed states of a MM-qudit hybrid system. The entanglement measure is based on a distance deriving from an adapted application of the Fubini-Study metric. This measure is invariant under local unitary transformations and has an explicit computable expression that we derive. In the specific case of MM-qubit systems, the measure assumes the physical interpretation of an obstacle to the minimum distance between infinitesimally close states. Finally, we quantify the robustness of entanglement of a state through the eigenvalues analysis of the metric tensor associated with it.QuantERA ERA-NET Co-fundEngineering and Physical Sciences Research Council (EPSRC

    Stable or plastic body shape? Emys orbicularis hatchlings-juveniles growth patterns under different ecological conditions.

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    To test if habitat could shape shell features of freshwater turtles starting from birth, we tested hatchlings of Emys orbicularis, randomly chosen from four clutches of the same locality, under two treatments, firm (pond habitat) vs running (river habitat) water regimes. Due to mortality at the beginning of the experiment, we finally considered only two clutches. Turtle shells were characterized at hatch and after one year of treatment by means of traditional and geometric morphometrics and phenotypic trajectories analysis were conducted on both types of data. Carapace growth was isometric both in proportion and shape, while plastron showed an allometric pattern: length increased more than width while the contour showed an expansion of the rear part and a compression of the front one. The hydrodynamic conditions during growth did not seem to affect the phenotypic trajectories of shell proportions nor those of plastron. On the contrary a significant effect was found on the phenotypic trajectory of carapace: the size component (but not the angle one) was positively influenced by the “pond” treatment, suggesting a different growth rate between the two environmental conditions. Hypotheses on possible ecological constraints derived from habitat conditions are presented and discussed

    Quantum–classical correspondence in spin–boson equilibrium states at arbitrary coupling

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    The equilibrium properties of nanoscale systems can deviate significantly from standard thermodynamics due to their coupling to an environment. We investigate this here for the ξ-angled spin–boson model, where we first derive a compact and general form of the classical equilibrium state including environmental corrections to all orders. Secondly, for the quantum spin–boson model we prove, by carefully taking a large spin limit, that Bohr’s quantum–classical correspondence persists at all coupling strengths. This shows, for the first time, the validity of the quantum–classical correspondence for an open system and gives insight into the regimes where the quantum system is well-approximated by a classical one. Finally, we provide the first classification of the coupling parameter regimes for the spin–boson model, from weak to ultrastrong, both for the quantum case and the classical setting. Our results shed light on the interplay of quantum and mean force corrections in equilibrium states of the spin–boson model, and will help draw the quantum to classical boundary in a range of fields, such as magnetism and exciton dynamics

    Stable or plastic body shape? Emys orbicularis hatchlings-juveniles growth patterns under different ecological conditions

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    To test if habitat could shape shell features of freshwater turtles starting from birth, we tested hatchlings of Emys orbicularis, randomly chosen from four clutches of the same locality, under two treatments, stagnant (pond habitat) vs lotic (river habitat) water regimes. Due to mortality at the beginning of the experiment, we finally considered only two clutches. Turtle shells were characterized initially at hatching and then after one year of treatment by means of traditional and geometric morphometrics, and phenotypic trajectories analyses were conducted on both types of data. Carapace growth was isometric both in proportion and shape, while plastron showed an allometric pattern: length increased more than width, while the contour showed an expansion at the rear and a compression of the front. The hydrodynamic conditions during growth did not seem to affect the phenotypic trajectories of the shell proportions or the plastron. On the contrary, a significant effect was found on the phenotypic trajectory of the carapace: the size component (but not the angle one) was positively influenced by the "lentic" treatment, suggesting a different growth rate between the two environmental conditions

    Quantum-classical correspondence in spin-boson equilibrium states at arbitrary coupling

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    It is known that the equilibrium properties of nanoscale systems can deviate significantly from standard thermodynamics due to their coupling to an environment. For the generalized Ξ\theta-angled spin-boson model, here we derive an explicit form of the classical mean force equilibrium state. Taking the large spin limit of the quantum spin-boson model, we demonstrate that the quantum-classical correspondence is maintained at arbitrary coupling strength. This correspondence gives insight into the conditions for a quantum system to be well-approximated by its classical counterpart. We further demonstrate that, counterintuitively, previously identified environment-induced 'coherences' in the equilibrium state of weakly coupled quantum spins, do not disappear in the classical case. Finally, we categorise various coupling regimes, from ultra-weak to ultra-strong, and find that the same value of coupling strength can either be 'weak' or 'strong', depending on whether the system is quantum or classical. Our results shed light on the interplay of quantum and mean force corrections in equilibrium states of the spin-boson model, and will help draw the quantum to classical boundary in a range of fields, such as magnetism and exciton dynamics

    Diagnostica Avanzata di Valvole di Regolazione

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    Il contributo riporta lo stato dell’arte, inclusi i piĂč recenti aggiornamenti, riguardo alle problematiche della diagnostica delle valvole di regolazione. Viene presentata una rassegna delle tecniche automatiche per la segnalazione di malfunzionamenti nelle valvole e per la distinzione delle diverse cause di bassa prestazione del loop di regolazione. Tra queste: presenza di attrito, perdita di aria di alimentazione, malfunzionamento del convertitore E/P, disturbi esterni, tuning del regolatore. Viene anche illustrato un sistema di diagnostica, sviluppato presso il CPCLab dell’UniversitĂ  di Pisa, implementato da diversi anni in impianti di raffineria e di generazione di energia elettrica, con esempi di applicazione. In particolare sono messi in evidenza i vantaggi derivanti da una diagnostica basata sulle variabili ausiliarie rese disponibile da strumentazione intelligente e da comunicazioni via Bus di campo

    Preoperative prediction of spinal cord ischemia after thoracic endovascular aortic repair

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    ObjectiveSpinal cord ischemia (SCI) is a devastating but potentially preventable complication of thoracic endovascular aortic repair (TEVAR). The purpose of this analysis was to determine what factors predict SCI after TEVAR.MethodsAll TEVAR procedures at a single institution were reviewed for patient characteristics, prior aortic repair history, aortic centerline of flow analysis, and procedural characteristics. SCI was defined as any lower extremity neurologic deficit that was not attributable to an intracranial process or peripheral neuropathy. Forty-three patient and procedural variables were evaluated individually for association with SCI. Those with the strongest relationships to SCI (P < .1) were included in a multivariable logistic regression model, and a stepwise variable elimination algorithm was bootstrapped to derive a best subset of predictors from this model.ResultsFrom 2002 to 2013, 741 patients underwent TEVAR for various indications, and 68 (9.2%) developed SCI (permanent: n = 38; 5.1%). Because of the lack of adequate imaging for centerline analysis, 586 patients (any SCI, n = 43; 7.4%) were subsequently analyzed. Patients experiencing SCI after TEVAR were older (SCI, 72 ± 11 years; no SCI, 65 ± 15 years; P < .0001) and had significantly higher rates of multiple cardiovascular risk factors. The stepwise selection procedure identified five variables as the most important predictors of SCI: age (odds ratio [OR] multiplies by 1.3 per 10 years; 95% confidence interval [CI], 0.9-1.8, P = .06), aortic coverage length (OR multiplies by 1.3 per 5 cm; CI, 1.1-1.6; P = .002), chronic obstructive pulmonary disease (OR, 1.9; CI, 0.9-4.1; P = .1), chronic renal insufficiency (creatinine concentration ≄ 1.6 mg/dL; OR, 1.9; CI, 0.8-4.2; P = .1), and hypertension (defined as chart history or medication; OR, 6.4; CI, 2.6-18; P < .0001). A logistic regression model with just these five covariates had excellent discrimination (area under the receiver operating characteristic curve = .83) and calibration (χ2 = 9.8; P = .28).ConclusionsThis analysis generated a simple model that reliably predicts SCI after TEVAR. This clinical tool can assist decision-making about when to proceed with TEVAR, guide discussions about intervention risk, and help determine when maneuvers to mitigate SCI risk should be implemented

    Ultrasound lung comets in systemic sclerosis: a chest sonography hallmark of pulmonary interstitial fibrosis

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    Objective. To assess the correlation between ultrasound lung comets (ULCs, a recently described echographic sign of interstitial lung fibrosis) and the current undisputed gold-standard high-resolution CT (HRCT) to detect pulmonary fibrosis in patients with SSc. Methods. We enrolled 33 consecutive SSc patients (mean age 5413 years, 30 females) in the Rheumatology Clinic of the University of Pisa. We assessed ULCs and chest HRCT within 1 week independently in all the patients. ULC score was obtained by summing the number of lung comets on the anterior and posterior chest. Pulmonary fibrosis was quantified by HRCT with a previously described 30-point Warrick score. Results. Presence of ULCs (defined as a total number more than 10) was observed in 17 (51%) SSc patients. Mean ULC score was 3750, higher in the diffuse than in the limited form (7366 vs 2135; P<0.05). A significant positive linear correlation was found between ULCs and Warrick scores (r?0.72; P<0.001). Conclusions. ULCs are often found in SSc, are more frequent in the diffuse than the limited form and are reasonably well correlated with HRCT-derived assessment of lung fibrosis. They represent a simple, bedside, radiation-free hallmark of pulmonary fibrosis of potential diagnostic and prognostic value

    A20, a modulator of smooth muscle cell proliferation and apoptosis, prevents and induces regression of neointimal hyperplasia

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    A20 is a NF‐ÎșB‐dependent gene that has dual anti‐inflammatory and antiapoptotic functions in endothelial cells (EC). The function of A20 in smooth muscle cells (SMC) is unknown. We demonstrate that A20 is induced in SMC in response to inflammatory stimuli and serves an anti‐inflammatory function via blockade of NF‐ÎșB and NF‐ÎșB‐dependent proteins ICAM‐1 and MCP‐1. A20 inhibits SMC proliferation via increased expression of cyclin‐dependent kinase inhibitors p21waf1 and p27kip1. Surprisingly, A20 sensitizes SMC to cytokine‐ and Fas‐mediated apoptosis through a novel NO‐dependent mechanism. In vivo, adenoviral delivery of A20 to medial rat carotid artery SMC after balloon angioplasty prevents neointimal hyperplasia by blocking SMC proliferation and accelerating re‐endothelialization, without causing apoptosis. However, expression of A20 in established neointimal lesions leads to their regression through increased apoptosis. This is the first demonstration that A20 exerts two levels of control of vascular remodeling and healing. A20 prevents neointimal hyperplasia through combined anti‐inflammatory and antiproliferative functions in medial SMC. If SMC evade this first barrier and neointima is formed, A20 has a therapeutic potential by uniquely sensitizing neointimal SMC to apoptosis. A20‐based therapies hold promise for the prevention and treatment of neointimal disease.—Patel, V. I., Daniel, S., Longo, C. R., Shrikhande, G. V., Scali, S. T., Czismadia, E., Groft, C. M., Shukri, T., Motley‐Dore, C., Ramsey, H. E., Fisher, M. D., Grey, S. T., Arvelo, M. B., Ferran, C. A20, a modulator of smooth muscle cell proliferation and apoptosis, prevents and induces regression of neointimal hyperplasia. FASEB J. 20, 1418–1430 (2006)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154452/1/fsb2fj054981com.pd

    Work addiction and its association with personality traits, general distress, and self-esteem among adult Italian workers

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    Background: Work addiction has become a topic of increasing research interest but has been little studied in Italy. Therefore, the aim of the present study was to investigate the associations between work addiction, assessed with a recently validated psychometric scale (i.e., Italian version of Bergen Work Addiction Scale, [BWAS]) and other psychological constructs. Methods: The sample comprised 367 Italian workers (Mean 16.11 years; SD±11.28) who completed a survey including the BWAS (Mean 19.422; SD±6.365), Depression Anxiety Stress Scales-21 (Mean 40.866; SD±29.865), Dutch Workaholism Scale (Mean 24.837; SD±6.488), Need for Recovery Scale (Mean 12.946; SD±7.340), Ten Item Personality Inventory (TIPI, Extraversion (Mean 4.253; SD±1.506); Agreeableness (Mean 5.431; SD±1.111), Conscientiousness (Mean 5.792; SD±1.067), Neuroticism (Mean 4.507; SD±1.480), Openness (Mean 4.801; SD±1.122), and Rosenberg’s Self-Esteem Scale (Mean 21.850; SD±6.796). Results: The results indicated that work addiction was positively associated with stress, anxiety, and depression, as well as with the number of hours worked and need for recovery. Moreover, BWAS scores explained 20.1% of an individual’s general psychological distress (i.e., depression, anxiety, and stress). Personality variables explained only a small amount of the variance in work addiction (15.4%). Conclusion: In the present study, a positive and significant association was found between the BWAS (assessing work addiction) and the DUWAS (assessing workaholism). Although work addiction and workaholism are different constructs, they have many characteristics in common. The study expands the work addiction literature base and demonstrates important associating factors in the Italian context
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