5,532 research outputs found
Coarse Grained Liouville Dynamics of piecewise linear discontinuous maps
We compute the spectrum of the classical and quantum mechanical
coarse-grained propagators for a piecewise linear discontinuous map. We analyze
the quantum - classical correspondence and the evolution of the spectrum with
increasing resolution. Our results are compared to the ones obtained for a
mixed system.Comment: 11 pages, 8 figure
Mandatory vaccinations in European countries, undocumented information, false news and the impact on vaccination uptake: the position of the Italian pediatric society.
BACKGROUND: High rates of vaccination coverage are important in preventing infectious diseases. Enforcing mandatory vaccinations is one of the strategies that some Countries adopted to protect the community when vaccination coverage is not satisfactory. In Italy, in 2017 vaccination against diphtheria, tetanus, pertussis, hepatitis B, poliovirus, Haemophilus influenzae type b, measles, mumps, rubella and varicella became compulsory in childhood. In order to contrast vaccination policies, anti-vaccination campaigns contribute to the spread of fake news. Among them, there is the false information that Italy is the only one country with mandatory vaccination policy. Aim of our study is confronting vaccination policies in children under 18 months against among different European countries for the following vaccines: diphtheria, tetanus, pertussis, hepatitis B, poliovirus, Haemophilus influenzae type b, measles, mumps, rubella and varicella. METHODS: Information on policies of mandatory or recommended vaccinations of the European Countries were gathered by ECDC and compared to the Italian one. RESULTS: European Countries recommend or contemplate compulsory vaccines. Among them, eleven Countries (35.4%) have mandatory vaccinations for at least one out of diphtheria, tetanus, pertussis, hepatitis B, poliovirus, Haemophilus influenzae type b, measles, mumps, rubella and varicella vaccine. CONCLUSION: Not only in Italy, vaccination against diphtheria, tetanus, pertussis, hepatitis B, poliovirus, Haemophilus influenzae type b, measles, mumps, rubella and varicella is mandatory in children under 18 months. Other European countries adopted compulsory policies in order to prevent the spread of infectious diseases and to protect the community
A Temporal Analysis of the Euphausiid Assemblage in the Gulf of Mexico after the Deepwater Horizon Oil Spill, with Notes on Seasonal Reproduction
This thesis presents the results of the first multi-year study on the euphausiid assemblage in the vicinity of the Deepwater Horizon oil spill (DWHOS), covering depths down to 1000 m. There are no data on the euphausiid assemblage from this region prior to the oil spill; therefore, the data in this study were analyzed with respect to year (samples collected in 2011 vs. those collected between 2015 – 2016), and season (May vs. August) to determine if any trends were present. These results presented here show a statistically significant decrease in both abundance and biomass between 2011 and 2015 – 2016, indicating that the assemblage has been declining since 2011, along with a continued decline from May 2016 to May 2017. Seasonal effects were also present, as abundance and biomass were statistically higher in May than in August in both 2011 and 2016. In addition, the percentage of gravid females of the grouped species, Nematoscelis atlantica/microps, was also higher in May for both years, but only statistically significant in 2016. This seasonal variability may possibly be linked to food availability as a result of seasonal phytoplankton blooms. The information presented here will act as a reference point for future studies in the Gulf of Mexico (GOM), to aid in understanding how the euphausiid assemblage responds to anthropogenic events
Media devices in pre-school children: the recommendations of the Italian pediatric society
BACKGROUND: Young children are too often exposed to mobile devices (MD) and most of them had their own device. The adverse effects of a early and prolonged exposure to digital technology on pre-school children has been described by several studies. Aim of the study is to analyze the consequences of MD exposure in pre-school children. METHODS: We analyzed the documented effects of media exposure on children's mental and physical health. RESULTS: According to recent studies, MD may interfere with learning, children development, well being, sleep, sight, listening, caregiver-child relationship. DISCUSSION: Pediatricians should be aware of both the beneficial and side effects of MD and give advice to the families, according to children's age. CONCLUSION: In according to literature, the Italian Pediatric Society suggest that the media device exposure in childhood should be modulated by supervisors
Performance analysis of a full order sensorless control adaptive observer for doubly-fed induction generator in grid connected operation
This paper focuses on the performance analysis of a sensorless control for a Doubly Fed Induction Generator (DFIG) in grid-connected operation for turbine-based wind generation systems. With reference to a conventional stator flux based Field Oriented Control (FOC), a full-order adaptive observer is implemented and a criterion to calculate the observer gain matrix is provided. The observer provides the estimated stator flux and an estimation of the rotor position is also obtained through the measurements of stator and rotor phase currents. Due to parameter inaccuracy, the rotor position estimation is affected by an error. As a novelty of the discussed approach, the rotor position estimation error is considered as an additional machine parameter, and an error tracking procedure is envisioned in order to track the DFIG rotor position with better accuracy. In particular, an adaptive law based on the Lyapunov theory is implemented for the tracking of the rotor position estimation error, and a current injection strategy is developed in order to ensure the necessary tracking sensitivity around zero rotor voltages. The roughly evaluated rotor position can be corrected by means of the tracked rotor position estimation error, so that the corrected rotor position is sent to the FOC for the necessary rotating coordinate transformation. An extensive experimental analysis is carried out on an 11 kW, 4 poles, 400 V/50 Hz induction machine testifying the quality of the sensorless control
Non \ue8 pi\uf9 quella di una volta. La mafia e le attivit\ue0 estorsive in Sicilia
Il volume presenta i risultati di una ricerca volta alla descrizione dei fenomeni estorsivi e della loro intensit\ue0 in Sicilia, raccontando, sulla base di appositi parametri oggettivi e di valutazioni soggettive degli esponenti del mondo delle associazioni e delle forze dell\u2019ordine, le aree pi\uf9 esposte, quelle meno esposte, quelle dove i fenomeni hanno una rilevanza residuale, in una fase in cui i sodalizi mafiosi sono sempre pi\uf9 pressati dall\u2019azione di contrasto. Per raggiungere questo obiettivo ci si \ue8 avvalsi di strumenti qualitativi e dati quantitativi, approfondendo l\u2019analisi delle trasformazioni delle condotte estorsive durante la crisi, concentrandosi in modo specifico su casi emersi nell\u2019ambito di recenti inchieste giudiziarie. Il libro ricostruisce anche la prospettiva e le difficolt\ue0 di alcuni imprenditori siciliani che, dopo aver pagato il pizzo, hanno scelto di denunciare i propri estorsori e di collaborare con le istituzioni
Battery losses in a MMC for BEVS application
Objective:
This paper analyses the Modular Multilevel Converter (MMC) topology, where each individual Sub Module (SM), in half bridge
configuration, is directly fed by an elementary electrochemical cell.
Methods:
The aim is to investigate how the reference voltages influence the cells currents waveforms, determining how the active powers and
the losses are distributed among the cells. Considering a 2-level Voltage Source Inverter (VSI) topology working in the same
conditions, the ratio between the MMC total cells losses and VSI total cells losses is calculated. After showing the system
architecture and mathematical model, the cells current waveform investigation is presented and detailed both for triangular and
sinusoidal voltage reference waveform
AdipoRon and Pancreatic Ductal Adenocarcinoma: a future perspective in overcoming chemotherapy-induced resistance?
Kernel estimates for nonautonomous Kolmogorov equations with potential term
Using time dependent Lyapunov functions, we prove pointwise upper bounds for
the heat kernels of some nonautonomous Kolmogorov operators with possibly
unbounded drift and diffusion coefficients and a possibly unbounded potential
term
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