2,164 research outputs found
Interacting epidemics and coinfection on contact networks
The spread of certain diseases can be promoted, in some cases substantially,
by prior infection with another disease. One example is that of HIV, whose
immunosuppressant effects significantly increase the chances of infection with
other pathogens. Such coinfection processes, when combined with nontrivial
structure in the contact networks over which diseases spread, can lead to
complex patterns of epidemiological behavior. Here we consider a mathematical
model of two diseases spreading through a single population, where infection
with one disease is dependent on prior infection with the other. We solve
exactly for the sizes of the outbreaks of both diseases in the limit of large
population size, along with the complete phase diagram of the system. Among
other things, we use our model to demonstrate how diseases can be controlled
not only by reducing the rate of their spread, but also by reducing the spread
of other infections upon which they depend.Comment: 9 pages, 3 figure
Hydrogen vs. Battery in the long-term operation. A comparative between energy management strategies for hybrid renewable microgrids
The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time, the use of renewable energy sources is pursued to address decarbonization targets, but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing, at the same time, the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense, the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However, hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation, demand and storage, energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load, storage efficiency, operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy, while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation
Plasma boosted electron beams for driving Free Electron Lasers
In this paper, we report results of simulations, in the framework of both
EuPRAXIA \cite{Walk2017} and EuPRAXIA@SPARC\_LAB \cite{Ferr2017} projects,
aimed at delivering a high brightness electron bunch for driving a Free
Electron Laser (FEL) by employing a plasma post acceleration scheme. The
boosting plasma wave is driven by a tens of \SI{}{\tera\watt} class laser and
doubles the energy of an externally injected beam up to \GeV{1}. The injected
bunch is simulated starting from a photoinjector, matched to plasma, boosted
and finally matched to an undulator, where its ability to produce FEL radiation
is verified to yield O(\num{e11}) photons per shot at \nm{2.7}.Comment: 5 pages, 2 figure
Determinants of depression in 111 italian patients with systemic sclerosis
Background: A high prevalence of depressive symptoms has been described in systemic sclerosis (SSc), but no clear association with organ involvement or objective indices of disease severity has been depicted. To date, no effort has been made to determine the prevalence of depressive symptoms in Italian patients with SSc or to clarify their cause. Methods: One-hundred-eleven SSc patients were asked to fill in the Beck Depression Inventory (BDI) questionnaire, the scleroderma Health Assessment Questionnaire (sHAQ) and two additional questions assessing the patient's familiar support and the social consequences of the patient's change in physical appearnace. Results: Thirty-seven subjects (33.4%) presented mild to severe depressive symptoms (BDI ³17). On univariate analysis the diffuse cutaneous form of the disease (p=0.019), higher pulmonary systolic pressures on echocardiogram (p=0.016), lower FVC percentage of predicted values (p=0.022), higher sHAQ values (p<0.001) or higher VAS values for pain (p=0.007), lung involvement (p=0.02), Raynaud's phenomenon severity (p=0.002), ulcers severity (p=0.006) or disease severity (p<0.001), were associated with the presence of pathologic depressive symptoms. On multivariate analysis only the VAS for disease severity relevant to BDI scores (p=0.016). Social behaviour changes due to SSc-related physical involvement were reported in 14 patients (38%) with depressive symptoms (p=0,006) and were more likely to be observed in younger patients (p=0.001) with a more severe Raynauds's phenomenon (p=0.013). Conclusions: Mild to severe depressive symptoms are common in SSc patients especially in those with a worse perception of disease severity, these patients should be carefully monitored and a psychological assistance counselled whenever necessary
Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB
The plasma-based acceleration is an encouraging technique to overcome the
limits of the accelerating gradient in the conventional RF acceleration. A
plasma accelerator is able to provide accelerating fields up to hundreds of
, paving the way to accelerate particles to several MeV over a short
distance (below the millimetre range). Here the characteristics of preliminary
electron beams obtained with the self-injection mechanism produced with the
FLAME high-power laser at the SPARC_LAB test facility are shown. In detail,
with an energy laser on focus of and a pulse temporal length (FWHM) of
, we obtained an electron plasma density due to laser ionization of
about , electron energy up to and beam
charge in the range .Comment: 6 pages, 11 figures, conference EAAC201
Development of a Disposable Gold Electrodes-Based Sensor for Electrochemical Measurements of cDNA Hybridization
AbstractThis work deals with the development of a disposable electrochemical biosensor for the specific detection of short DNA sequences. The sensor is an amperometric transducer with three planar electrodes, comprising a working, a counter and a pseudo-reference electrode, all made of a gold layer over a polycarbonate substrate. For the development of the genosensor, the working electrode was modified using thiol-tethered 33-mer DNA probe by chemisorptions, in a concentration range from 0.1 μM to 5 μM. Immobilization of ssDNA on gold surface was monitored with electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) in Fe(CN)64−/13− and Ruthenium(II)/(III) solutions. The time dependence of ssDNA probe immobilization was also studied. The hybridization detection is then compared with EIS and DPV measurements
EuPRAXIA@SPARC_LAB: the high-brightness RF photo-injector layout proposal
At EuPRAXIA@SPARC_LAB, the unique combination of an advanced high-brightness
RF injector and a plasma-based accelerator will drive a new multi-disciplinary
user-facility. The facility, that is currently under study at INFN-LNF
Laboratories (Frascati, Italy) in synergy with the EuPRAXIA collaboration, will
operate the plasma-based accelerator in the external injection configuration.
Since in this configuration the stability and reproducibility of the
acceleration process in the plasma stage is strongly influenced by the
RF-generated electron beam, the main challenge for the RF injector design is
related to generating and handling high quality electron beams. In the last
decades of R&D activity, the crucial role of high-brightness RF photo-injectors
in the fields of radiation generation and advanced acceleration schemes has
been largely established, making them effective candidates to drive
plasma-based accelerators as pilots for user facilities. An RF injector
consisting in a high-brightness S-band photo-injector followed by an advanced
X-band linac has been proposed for the EuPRAXIA@SPARC_LAB project. The electron
beam dynamics in the photo-injector has been explored by means of simulations,
resulting in high-brightness, ultra-short bunches with up to 3 kA peak current
at the entrance of the advanced X-band linac booster. The EuPRAXIA@SPARC_LAB
high-brightness photo-injector is described here together with performance
optimisation and sensitivity studies aiming to actual check the robustness and
reliability of the desired working point.Comment: 5 pages,5 figures, EAAC201
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