4,614 research outputs found
High-energy behavior of hadronic total cross sections from lattice QCD
By means of a nonperturbative approach to soft high-energy hadron-hadron
scattering, based on the analytic continuation of Wilson-loop correlation
functions from Euclidean to Minkowskian theory, we shall investigate the
asymptotic energy dependence of hadron-hadron total cross sections in lattice
QCD: we will show, using best fits of the lattice data with proper functional
forms satisfying unitarity and other physical constraints, how indications
emerge in favor of a universal asymptotic high-energy behavior of the kind for hadronic total cross sections.Comment: Talk given (by E. Meggiolaro) at the "16th High-Energy Physics
International Conference in Quantum ChromoDynamics" (QCD 12), Montpellier
(France), 2-6 July 2012; 4 pages, 1 figure, 2 table
Power system investment optimization to identify carbon neutrality scenarios for Italy
In 2021, the European Commission has adopted the Fit-for-55 policy package,
legally binding European countries to reduce their CO2 emissions by 55% with
respect to 1990, a first step to achieve carbon neutrality in 2050. In this
context, it is crucial to help national policymakers to choose the most
appropriate technologies to achieve these goals and energy system modelling can
be a valuable tool. This article presents a model of the Italian power system
realized employing the open energy modelling framework Oemof. A Linear
Programming Optimization is implemented to evaluate how to minimise system
costs at decreasing CO2 emissions in 2030. The developed tool is applied to
evaluate different research questions: i) pathway towards full decarbonization
and power self-sufficiency of the electricity sector in Italy, ii) relevance of
flexibility assets in power grids: li-ion batteries, hydrogen storage and
transmission lines reinforcement. A 55% CO2 emissions reduction for the actual
Italian power sector can be achieved through an increase of 30% of the total
annual system cost. Full decarbonization can be reached with four times today's
annual costs, which could be lowered with sector coupling and considering more
technologies.Comment: 18 pages, 13 figure
Commercial hemp seed oils: a multimethodological characterization
Nine commercial hemp seed oils from different countries were studied using a multimethodological approach to obtain information about their quality and chemical composition. Due to the lack of a specific regulation for hemp seed oils, quality parameters used in the case of olive oils (free acidity, peroxides number, spectrophotometer parameters) and anisidine number were measured and compared with those reported for extra virgin olive oil (EVOO). Free acidity and peroxides number showed a great variability, ranging from 0.4 to 17.24% and from 4.32 to 22.14 meqO2/kg, respectively, whereas the anisidine number ranged from 0.11 to 3.58. K232 value turned out to be generally below the limit reported for EVOO, whereas K270 and ΔK values were higher, with respect to EVOO limits, due to the high amount of tri-unsaturated fatty chains. Colorimetric analysis showed a peculiar curve trend that could represent the fingerprint of this product. Untargeted nuclear magnetic resonance methodology allowed to measure the amount of fatty chains, ω-6:ω-3 ratio, β-sitosterol, and aldehydes. The ω-6:ω-3 ratio turned out to be, in some cases, different from that reported on the bottle labels. Finally, lipoperoxidation assays were also carried out under different storage (light and temperature) and time exposure conditions, confirming that the exposure to direct light is the condition that interferes more with the product quality
Time-frequency mapping of two-colour photoemission driven by harmonic radiation
The use of few-femtosecond, extreme ultraviolet (XUV) pulses, produced by
high-order harmonic generation, in combination with few-femtosecond infrared
(IR) pulses in pump-probe experiments has great potential to disclose ultrafast
dynamics in molecules, nanostructures and solids. A crucial prerequisite is a
reliable characterization of the temporal properties of the XUV and IR pulses.
Several techniques have been developed. The majority of them applies phase
reconstruction algorithms to a photoelectron spectrogram obtained by ionizing
an atomic target in a pump-probe fashion. If the ionizing radiation is a single
harmonic, all the information is encoded in a two-color two-photon signal
called sideband (SB). In this work, we present a simplified model to interpret
the time-frequency mapping of the SB signal and we show that the temporal
dispersion of the pulses directly maps onto the shape of its spectrogram.
Finally, we derive an analytical solution, which allows us to propose a novel
procedure to estimate the second-order dispersion of the XUV and IR pulses in
real time and with no need for iterative algorithms
Zero Fluoroscopy Arrhythmias Catheter Ablation: A Trend Toward More Frequent Practice in a High-Volume Center
BACKGROUND: Awareness of radiation exposure risks associated to interventional cardiology procedures is growing. The availability of new technologies in electrophysiology laboratories has reduced fluoroscopy usage during arrhythmias ablations. The aim of this study was to describe procedures with and without X-Rays and to assess feasibility, safety, and short-term efficacy of zero fluoroscopy intervention in a high-volume center oriented to keep exposure to ionizing radiation as low as reasonably achievable. METHODS: Cardiac catheter ablations performed in our hospital since January 2017 to June 2021. RESULTS: A total of 1,853 procedures were performed with 1,957 arrhythmias treated. Rate of fluoroless procedures was 15.4% (285 interventions) with an increasing trend from 8.5% in 2017 to 22.9% of first semester 2021. The most frequent arrhythmia treated was atrial fibrillation (646; 3.6% fluoroless) followed by atrioventricular nodal reentrant tachycardia (644; 16.9% fluoroless), atrial flutter (215; 8.8% fluoroless), ventricular tachycardia (178; 17.4% fluoroless), premature ventricular contraction (162; 48.1% fluoroless), and accessory pathways (112; 31.3% fluoroless). Although characteristics of patients and operative details were heterogeneous among treated arrhythmias, use of fluoroscopy did not influence procedure duration. Moreover, feasibility and efficacy were 100% in fluoroless ablations while the rate of major complications was very low and no different with or without fluoroscopy (0.45 vs. 0.35%). CONCLUSION: Limiting the use of X-Rays is necessary, especially when the available technologies allow a zero-use approach. A lower radiation exposure may be reached, reducing fluoroscopy usage whenever possible during cardiac ablation procedures with high safety, full feasibility, and efficacy
Clinical Care Conditions and Needs of Palliative Care Patients from Five Italian Regions: Preliminary Data of the DEMETRA Project
In order to plan the right palliative care for patients and their families, it is essential to have detailed information about patients' needs. To gain insight into these needs, we analyzed five Italian local palliative care networks and assessed the clinical care conditions of patients facing the complexities of advanced and chronic disease. A longitudinal, observational, noninterventional study was carried out in five Italian regions from May 2017 to November 2018. Patients who accessed the palliative care networks were monitored for 12 months. Sociodemographic, clinical, and symptom information was collected with several tools, including the Necesidades Paliativas CCOMS-ICO (NECPAL) tool, the Edmonton Symptom Assessment System (ESAS), and interRAI Palliative Care (interRAI-PC). There were 1013 patients in the study. The majority (51.7%) were recruited at home palliative care units. Cancer was the most frequent diagnosis (85.4%), and most patients had at least one comorbidity (58.8%). Cancer patients reported emotional stress with severe symptoms (38.7% vs. 24.3% in noncancer patients; p = 0.001) and were less likely to have clinical frailty (13.3% vs. 43.9%; p < 0.001). Our study confirms that many patients face the last few months of life with comorbidities or extreme frailty. This study contributes to increasing the general knowledge on palliative care needs in a high-income country
Asymptotic Energy Dependence of Hadronic Total Cross Sections from Lattice QCD
The nonperturbative approach to soft high-energy hadron-hadron scattering,
based on the analytic continuation of Wilson-loop correlation functions from
Euclidean to Minkowskian theory, allows to investigate the asymptotic energy
dependence of hadron-hadron total cross sections in lattice QCD. In this paper
we will show, using best fits of the lattice data with proper functional forms
satisfying unitarity and other physical constraints, how indications emerge in
favor of a universal asymptotic high-energy behavior of the kind B log^2 s for
hadronic total cross sections.Comment: Revised and extended version; 29 pages, 4 figure
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