708 research outputs found

    Sustainable management of biomass energy in rural and urban context

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    The most sustainable energy is the energy not used. Best way to (not) use energy is the proper design of a facility or an energy consuming system. The remaining energy needs have to be covered with energy utilisation of waste materials, renewable energy sources and, until the previous solutions are not sufficient to satisfy the energy demands, the last is the use of conventional fossil and nuclear energy sources. In terms of renewable energy, biomass has an important role today. However, there is a difference between available inputs and utilisation when considering biomass energy possibilities in rural and urban context. This paper suggests biomass energy possibilities that are recommendable in rural context: possibilities of solid biomass combustion, of liquid biofuels and of anaerobe digestion. Also important are possibilities of solid biomass combustion and wet biomass digestion for urban energy production, although with some remarks on system considerations of urban biomass. Most advanced solutions for sustainable management of biomass energy include circular systems, both in rural and urban context, as recommended

    Filling a silo with a mixture of grains: Friction-induced segregation

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    We study the filling process of a two-dimensional silo with inelastic particles by simulation of a granular media lattice gas (GMLG) model. We calculate the surface shape and flow profiles for a monodisperse system and we introduce a novel generalization of the GMLG model for a binary mixture of particles of different friction properties where, for the first time, we measure the segregation process on the surface. The results are in good agreement with a recent theory, and we explain the observed small deviations by the nonuniform velocity profile.Comment: 10 pages, 5 figures, to be appear in Europhys. Let

    On the characterisation of paired monotone metrics

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    Hasegawa and Petz introduced the notion of dual statistically monotone metrics. They also gave a characterisation theorem showing that Wigner-Yanase-Dyson metrics are the only members of the dual family. In this paper we show that the characterisation theorem holds true under more general hypotheses.Comment: 12 pages, to appear on Ann. Inst. Stat. Math.; v2: changes made to conform to accepted version, title changed as wel

    Pricing currency derivatives under the benchmark approach

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    © 2014 Elsevier B.V. This paper considers the realistic modelling of derivative contracts on exchange rates. We propose a stochastic volatility model that recovers not only the typically observed implied volatility smiles and skews for short dated vanilla foreign exchange options but allows one also to price payoffs in foreign currencies, lower than possible under classical risk neutral pricing, in particular, for long dated derivatives. The main reason for this important feature is the strict supermartingale property of benchmarked savings accounts under the real world probability measure, which the calibrated parameters identify under the proposed model. Using a real dataset on vanilla option quotes, we calibrate our model on a triangle of currencies and find that the risk neutral approach fails for the calibrated model, while the benchmark approach still works

    Amphibian peptides for skin protection and healing

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    BACKGROUND: Amphibians are currently suffering a dramatic decline worldwide, mainly due to chytridiomycosis, a skin infection caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). An important natural defense of amphibian skin is the production of antimicrobial peptides (AMPs) by granular glands in the dermis. AMPs collected from several species of frogs successfully inhibit the growth of Bd in vitro. Besides their anti-microbial and anti-fungal activities, AMPs have been shown to exert other biological effects such as anti-viral, anti-tumor, anti-oxidant, immunomodulating and wound healing. AIM: We intended to test the efficacy of AMPs as cutaneous defenses in frog species either resistant or susceptible to Bd. METHODS: 3 frog species (Gastrotheca nebulanastes (GN), G. excubitor (GE) and Hypsiboas gladiator (HG), were collected in montane scrub, cloud forest and high elevation grassland habitats near Manu National Park in southeastern Peru. AMP secretion was stimulated by injection of norepinephrine into the dorsal lymph sacks. AMPs were then purified by chromatographic techniques. The human endothelial cell line HECV was treated with AMP concentrations ranging from 0.005 to 50 \ub5g/mL. Cell viability was verified by MTT test. Wound healing properties were analyzed by scratch wound assay. AMP inhibition strength against Bd growth was measured in vitro by incubating Bd zoospores with different concentrations of AMPs. RESULTS: Treatment with AMPs secreted from GN, GE and HG did not affect HECV cell viability at any concentration tested. No significant differences in cell migration rate were observed in HECV cells scratched and treated with GN and GE AMPs. Only HG peptides showed wound healing properties as well as strong Bd growth inhibiting ability. CONCLUSIONS: Stimulation of wound healing mechanisms and inhibition of Bd growth by skin AMPs might both contribute to HG resistance to chytridiomycosis. Understanding the role of skin defenses may lead to the development of novel Bd mitigation strategies. Possible applications of amphibian AMPs in skin medicine deserve attention and further studies. This work was funded by the European Commission (Tender ENV.B.3/SER/2016/0028, Mitigating a new infectious disease in salamanders to counteract the loss of European biodiversity) and by Parco Nazionale delle Cinque Terre

    Silybin counteracts lipid excess and oxidative stress in cultured steatotic hepatic cells

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    AIM: To investigate in vitro the therapeutic effect and mechanisms of silybin in a cellular model of hepatic steatosis. METHODS: Rat hepatoma FaO cells were loaded with lipids by exposure to 0.75 mmol/L oleate/palmitate for 3 h to mimic liver steatosis. Then, the steatotic cells were incubated for 24 h with different concentrations (25 to 100 mol/L) of silybin as phytosome complex with Vitamin E. The effects of silybin on lipid accumulation and metabolism, and on indices of oxidative stress were evaluated by absorption and fluorescence microscopy, quantitative real-time PCR, Western blot, spectrophotometric and fluorimetric assays. RESULTS: Lipid-loading resulted in intracellular triglyceride (TG) accumulation inside lipid droplets, whose number and size increased. TG accumulation was mediated by increased levels of peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding protein-1c (SREBP-1c). The lipid imbalance was associated with higher production of reactive oxygen species (ROS) resulting in increased lipid peroxidation, stimulation of catalase activity and activation of nuclear factor kappa-B (NF-B). Incubation of steatotic cells with silybin 50 mol/L significantly reduced TG accumulation likely by promoting lipid catabolism and by inhibiting lipogenic pathways, as suggested by the changes in carnitine palmitoyltransferase 1 (CPT-1), PPAR and SREBP-1c levels. The reduction in fat accumulation exerted by silybin in the steatotic cells was associated with the improvement of the oxidative imbalance caused by lipid excess as demonstrated by the reduction in ROS content, lipid peroxidation, catalase activity and NF-B activation

    The Italian document: decisions for intensive care when there is an imbalance between care needs and resources during the COVID-19 pandemic

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    Background: In early 2020, the Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care (SIAARTI) published clinical ethics recommendations for the allocation of intensive care during COVID-19 pandemic emergency. Later the Italian National Institute of Health (ISS) invited SIAARTI and the Italian Society of Legal and Insurance Medicine to prepare a draft document for the definition of triage criteria for intensive care during the emergency, to be implemented in case of complete saturation of care resources. Methods: Following formal methods, including two Delphi rounds, a multidisciplinary group with expertise in intensive care, legal medicine and law developed 12 statements addressing: (1) principles and responsibilities; (2) triage; (3) previously expressed wishes; (4) reassessment and shifting to palliative care; (5) collegiality and transparency of decisions. The draft of the statements, with their explanatory comments, underwent a public consultation opened to Italian scientific or technical-professional societies and other stakeholders (i.e., associations of citizens, patients and caregivers; religious communities; industry; public institutions; universities and research institutes). Individual healthcare providers, lay people, or other associations could address their comments by e-mail. Results: Eight stakeholders (including scientific societies, ethics organizations, and a religious community), and 8 individuals (including medical experts, ethicists and an association) participated to the public consultation. The stakeholders’ agreement with statements was on average very high (ranging from 4.1 to 4.9, on a scale from 1—full disagreement to 5—full agreement). The 4 statements concerning triage stated that in case of saturation of care resources, the intensive care triage had to be oriented to ensuring life-sustaining treatments to as many patients as possible who could benefit from them. The decision should follow full assessment of each patient, taking into account comorbidities, previous functional status and frailty, current clinical condition, likely impact of intensive treatment, and the patient's wishes. Age should be considered as part of the global assessment of the patient. Conclusions: Lacking national guidelines, the document is the reference standard for healthcare professionals in case of imbalance between care needs and available resources during a COVID-19 pandemic in Italy, and a point of reference for the medico-legal assessment in cases of dispute

    Potential for Lung Recruitment and Ventilation-Perfusion Mismatch in Patients With the Acute Respiratory Distress Syndrome From Coronavirus Disease 2019

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    OBJECTIVES: Severe cases of coronavirus disease 2019 develop the acute respiratory distress syndrome, requiring admission to the ICU. This study aimed to describe specific pathophysiological characteristics of acute respiratory distress syndrome from coronavirus disease 2019. DESIGN: Prospective crossover physiologic study. SETTING: ICU of a university-affiliated hospital from northern Italy dedicated to care of patients with confirmed diagnosis of coronavirus disease 2019. PATIENTS: Ten intubated patients with acute respiratory distress syndrome and confirmed diagnosis of coronavirus disease 2019. INTERVENTIONS: We performed a two-step positive end-expiratory pressure trial with change of 10\u2009cm H2O in random order. MEASUREMENTS AND MAIN RESULTS: At each positive end-expiratory pressure level, we assessed arterial blood gases, respiratory mechanics, ventilation inhomogeneity, and potential for lung recruitment by electrical impedance tomography. Potential for lung recruitment was assessed by the recently described recruitment to inflation ratio. In a subgroup of seven paralyzed patients, we also measured ventilation-perfusion mismatch at lower positive end-expiratory pressure by electrical impedance tomography. At higher positive end-expiratory pressure, respiratory mechanics did not change significantly: compliance remained relatively high with low driving pressure. Oxygenation and ventilation inhomogeneity improved but arterial CO2 increased despite unchanged respiratory rate and tidal volume. The recruitment to inflation ratio presented median value higher than previously reported in acute respiratory distress syndrome patients but with large variability (median, 0.79 [0.53-1.08]; range, 0.16-1.40). The FIO2 needed to obtain viable oxygenation at lower positive end-expiratory pressure was significantly correlated with the recruitment to inflation ratio (r = 0.603; p = 0.05). The ventilation-perfusion mismatch was elevated (median, 34% [32-45%] of lung units) and, in six out of seven patients, ventilated nonperfused units represented a much larger proportion than perfused nonventilated ones. CONCLUSIONS: In patients with acute respiratory distress syndrome from coronavirus disease 2019, potential for lung recruitment presents large variability, while elevated dead space fraction may be a specific pathophysiological trait. These findings may guide selection of personalized mechanical ventilation settings

    A Hedged Monte Carlo Approach to Real Option Pricing

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    In this work we are concerned with valuing optionalities associated to invest or to delay investment in a project when the available information provided to the manager comes from simulated data of cash flows under historical (or subjective) measure in a possibly incomplete market. Our approach is suitable also to incorporating subjective views from management or market experts and to stochastic investment costs. It is based on the Hedged Monte Carlo strategy proposed by Potters et al (2001) where options are priced simultaneously with the determination of the corresponding hedging. The approach is particularly well-suited to the evaluation of commodity related projects whereby the availability of pricing formulae is very rare, the scenario simulations are usually available only in the historical measure, and the cash flows can be highly nonlinear functions of the prices.Comment: 25 pages, 14 figure
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