101 research outputs found

    Fourier-Mukai functors and perfect complexes on dual numbers

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    We show that every exact fully faithful functor from the category of perfect complexes on the spectrum of dual numbers to the bounded derived category of a noetherian separated scheme is of Fourier-Mukai type. The kernel turns out to be an object of the bounded derived category of coherent complexes on the product of the two schemes. We also study the space of stability conditions on the derived category of the spectrum of dual numbers.Comment: 23 pages, Final version to appear in J. Algebr

    Hysteresis Modeling in Iron-Dominated Magnets Based on a Multi-Layered Narx Neural Network Approach

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    A full-fledged neural network modeling, based on a Multi-layered Nonlinear Autoregressive Exogenous Neural Network (NARX) architecture, is proposed for quasi-static and dynamic hysteresis loops, one of the most challenging topics for computational magnetism. This modeling approach overcomes drawbacks in attaining better than percent-level accuracy of classical and recent approaches for accelerator magnets, that combine hybridization of standard hysteretic models and neural network architectures. By means of an incremental procedure, different Deep Neural Network Architectures are selected, fine-tuned and tested in order to predict magnetic hysteresis in the context of electromagnets. Tests and results show that the proposed NARX architecture best fits the measured magnetic field behavior of a reference quadrupole at CERN. In particular, the proposed modeling framework leads to a percent error below 0.02% for the magnetic field prediction, thus outperforming state of the art approaches and paving a very promising way for future real time applications

    Antagonism of the prokineticin system prevents and reverses allodynia and inflammation in a mouse model of diabetes

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    Neuropathic pain is a severe diabetes complication and its treatment is not satisfactory. It is associated with neuroinflammation-related events that participate in pain generation and chronicization. Prokineticins are a new family of chemokines that has emerged as critical players in immune system, inflammation and pain. We investigated the role of prokineticins and their receptors as modulators of neuropathic pain and inflammatory responses in experimental diabetes. In streptozotocin-induced-diabetes in mice, the time course expression of prokineticin and its receptors was evaluated in spinal cord and sciatic nerves, and correlated with mechanical allodynia. Spinal cord and sciatic nerve pro- and anti-inflammatory cytokines were measured as protein and mRNA, and spinal cord GluR subunits expression studied. The effect of preventive and therapeutic treatment with the prokineticin receptor antagonist PC1 on behavioural and biochemical parameters was evaluated. Peripheral immune activation was assessed measuring macrophage and T-helper cytokine production. An up-regulation of the Prokineticin system was present in spinal cord and nerves of diabetic mice, and correlated with allodynia. Therapeutic PC1 reversed allodynia while preventive treatment blocked its development. PC1 normalized prokineticin levels and prevented the up-regulation of GluN2B subunits in the spinal cord. The antagonist restored the pro-/anti-inflammatory cytokine balance altered in spinal cord and nerves and also reduced peripheral immune system activation in diabetic mice, decreasing macrophage proinflammatory cytokines and the T-helper 1 phenotype. The prokineticin system contributes to altered sensitivity in diabetic neuropathy and its inhibition blocked both allodynia and inflammatory events underlying disease

    Effect of external PEEP in patients under controlled mechanical ventilation with an auto-PEEP of 5 cmH2O or higher.

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    In some patients with auto-positive end-expiratory pressure (auto-PEEP), application of PEEP lower than auto-PEEP maintains a constant total PEEP, therefore reducing the inspiratory threshold load without detrimental cardiovascular or respiratory effects. We refer to these patients as complete PEEP-absorbers. Conversely, adverse effects of PEEP application could occur in patients with auto-PEEP when the total PEEP rises as a consequence. From a pathophysiological perspective, all subjects with flow limitation are expected to be complete PEEP-absorbers, whereas PEEP should increase total PEEP in all other patients. This study aimed to empirically assess the extent to which flow limitation alone explains a complete PEEP-absorber behavior (i.e., absence of further hyperinflation with PEEP), and to identify other factors associated with it.One hundred patients with auto-PEEP of at least 5 cmH2O at zero end-expiratory pressure (ZEEP) during controlled mechanical ventilation were enrolled. Total PEEP (i.e., end-expiratory plateau pressure) was measured both at ZEEP and after applied PEEP equal to 80 % of auto-PEEP measured at ZEEP. All measurements were repeated three times, and the average value was used for analysis.Forty-seven percent of the patients suffered from chronic pulmonary disease and 52 % from acute pulmonary disease; 61 % showed flow limitation at ZEEP, assessed by manual compression of the abdomen. The mean total PEEP was 7 ± 2 cmH2O at ZEEP and 9 ± 2 cmH2O after the application of PEEP (p < 0.001). Thirty-three percent of the patients were complete PEEP-absorbers. Multiple logistic regression was used to predict the behavior of complete PEEP-absorber. The best model included a respiratory rate lower than 20 breaths/min and the presence of flow limitation. The predictive ability of the model was excellent, with an overoptimism-corrected area under the receiver operating characteristics curve of 0.89 (95 % CI 0.80-0.97).Expiratory flow limitation was associated with both high and complete PEEP-absorber behavior, but setting a relatively high respiratory rate on the ventilator can prevent from observing complete PEEP-absorption. Therefore, the effect of PEEP application in patients with auto-PEEP can be accurately predicted at the bedside by measuring the respiratory rate and observing the flow-volume loop during manual compression of the abdomen

    Antibacterial, antioxidant and hypoglycaemic effects of Thymus capitatus (L.) Hoffmanns. et Link leaves' fractions.

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    The aim of this study was to examine the bioactivity of the methanol fraction (MF) and n-hexane fraction (HF) of Thymus capitatus leaves in relation to their constituents analysed by gas chromatography and gas chromatography-mass spectrometry. The effects of T. capitatus on the growth of pathogenic bacteria associated with respiratory diseases (13 gram-positive and 4 gram-negative) were determined using a microdilution method. The MF was particularly effective on Streptococcus pneumoniae and Moraxella catarrhalis. The antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), ferric-reducing antioxidant power and β-carotene bleaching assays. A strong activity using β-carotene bleaching test was observed with the MF (IC50 of 0.7 μg/mL after 30 min of incubation). In the hypoglycaemic test, a selective α-amylase inhibitory activity was detected with the HF begging the most active (IC50 of 422.5 μg/mL). T. capitatus may represent a source of natural bioactive compounds
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