2,739 research outputs found
The pivotal role of Public Transport in designing the integration of mobility services and in operating MaaS offer: the concept of Shared Mobility Centre and the experience of Arezzo
The paper identifies the emerging trends and requirements in the mobility demand and the gaps between them and the offer. The paper shows how Public Authorities and Mobility Operators should provide a seamless mobility offer able to answer to mobility demand which is becoming more flexible and varied in typologies and needs. Public Transport must be the backbone of this integrated mobility offer including conventional services for main urban axes/corridors and FTS/ridesharing services for feeder, last mile and target groups services. ITS for Public Transport are the base systems to provide MaaS and Public Transport Operators should leader MaaS initiatives. Central role in the MaaS initiative must be allocated to Shared Mobility Centre as “umbrella” platform/organization able to coordinate conventional different transport services in a seamless mobility offer (from planning to operation to back-office functionalities interesting both Operators and Authorities). The experience of MaaS activated/under development in the city of Arezzo will be the opportunity to highlight some critical factors that must be guaranteed as supporting actions for MaaS
Vacuum Properties of Mesons in a Linear Sigma Model with Vector Mesons and Global Chiral Invariance
We present a two-flavour linear sigma model with global chiral symmetry and
vector and axial-vector mesons. We calculate pion-pion scattering lengths and
the decay widths of scalar, vector, and axial-vector mesons. It is demonstrated
that vector and axial-vector meson degrees of freedom play an important role in
these low-energy processes and that a reasonable theoretical description
requires globally chirally invariant terms other than the vector meson mass
term. An important question for meson vacuum phenomenology is the quark content
of the physical scalar f0(600) and a0(980) mesons. We investigate this question
by assigning the quark-antiquark sigma and a0 states of our model with these
physical mesons. We show via a detailed comparison with experimental data that
this scenario can describe all vacuum properties studied here except for the
decay width of the sigma, which turns out to be too small. We also study the
alternative assignment f0(1370) and a0(1450) for the scalar mesons. In this
case the decay width agrees with the experimental value, but the pion-pion
scattering length is too small. This indicates the necessity to
extend our model by additional scalar degrees of freedom.Comment: 22 pages, 6 figure
CHANTI: a Fast and Efficient Charged Particle Veto Detector for the NA62 Experiment at CERN
The design, construction and test of a charged particle detector made of
scintillation counters read by Silicon Photomultipliers (SiPM) is described.
The detector, which operates in vacuum and is used as a veto counter in the
NA62 experiment at CERN, has a single channel time resolution of 1.14 ns, a
spatial resolution of ~2.5 mm and an efficiency very close to 1 for penetrating
charged particles
The Glueball in a Chiral Linear Sigma Model with Vector Mesons
We present a two-flavour linear sigma model with global chiral symmetry and
(axial-)vector mesons as well as an additional glueball degree of freedom. We
study the structure of the well-established scalar resonances f0(1370) and
f0(1500): by a fit to experimentally known decay widths we find that f0(1370)
is predominantly a \bar{q}q state and f0(1500) is predominantly a glueball
state. The overall phenomenology of these two resonances can be well described.
Other assignments for our mixed quarkonium-glueball states are also tested, but
turn out to be in worse agreement with the phenomenology. As a by-product of
our analysis, the gluon condensate is determined.Comment: 8 page
Dynamical changes of the polar cap potential structure: an information theory approach
Some features, such as vortex structures often observed through a wide spread of spatial scales, suggest that ionospheric convection is turbulent and complex in nature. Here, applying concepts from information theory and complex system physics, we firstly evaluate a pseudo Shannon entropy, <i>H</i>, associated with the polar cap potential obtained from the Super Dual Auroral Radar Network (SuperDARN) and, then, estimate the degree of disorder and the degree of complexity of ionospheric convection under different Interplanetary Magnetic Field (IMF) conditions. The aforementioned quantities are computed starting from time series of the coefficients of the 4th order spherical harmonics expansion of the polar cap potential for three periods, characterised by: (i) steady IMF <i>B<sub>z</sub></i> > 0, (ii) steady IMF <i>B<sub>z</sub></i> < 0 and (iii) a double rotation from negative to positive and then positive to negative <i>B<sub>z</sub></i>. A neat dynamical topological transition is observed when the IMF <i>B<sub>z</sub></i> turns from negative to positive and vice versa, pointing toward the possible occurrence of an order/disorder phase transition, which is the counterpart of the large scale convection rearrangement and of the increase of the global coherence. This result has been confirmed by applying the same analysis to a larger data base of about twenty days of SuperDARN data, allowing to investigate the role of IMF <i>B<sub>y</sub></i> too
Molecular targets of developmental exposure to bisphenol A in diabesity: a focus on endoderm-derived organs
Several studies associate foetal human exposure to bisphenol A (BPA) to metabolic/endocrine diseases, mainly diabesity. They describe the role of BPA in the disruption of pancreatic beta cell, adipocyte and hepatocyte functions. Indeed, the complexity of the diabesity phenotype is due to the involvement of different endoderm-derived organs, all targets of BPA. Here, we analyse this point delineating a picture of different mechanisms of BPA toxicity in endoderm-derived organs leading to diabesity. Moving from epidemiological data, we summarize the in vivo experimental data of the BPA effects on endoderm-derived organs (thyroid, pancreas, liver, gut, prostate and lung) after prenatal exposure. Mainly, we gather molecular data evidencing harmful effects at low-dose exposure, pointing to the risk to human health. Although the fragmentation of molecular data does not allow a clear conclusion to be drawn, the present work indicates that the developmental exposure to BPA represents a risk for endoderm-derived organs development as it deregulates the gene expression from the earliest developmental stages. A more systematic analysis of BPA impact on the transcriptomes of endoderm-derived organs is still missing. Here, we suggest in vitro toxicogenomics approaches as a tool for the identification of common mechanisms of BPA toxicity leading to the diabesity in organs having the same developmental origin
Developement of real time diagnostics and feedback algorithms for JET in view of the next step
Real time control of many plasma parameters will be an essential aspect in
the development of reliable high performance operation of Next Step Tokamaks.
The main prerequisites for any feedback scheme are the precise real-time
determination of the quantities to be controlled, requiring top quality and
highly reliable diagnostics, and the availability of robust control algorithms.
A new set of real time diagnostics was recently implemented on JET to prove the
feasibility of determining, with high accuracy and time resolution, the most
important plasma quantities. With regard to feedback algorithms, new
model–based controllers were developed to allow a more robust control of
several plasma parameters. Both diagnostics and algorithms were successfully
used in several experiments, ranging from H-mode plasmas to configuration with
ITBs. Since elaboration of computationally heavy measurements is often
required, significant attention was devoted to non-algorithmic methods like
Digital or Cellular Neural/Nonlinear Networks. The real time hardware and
software adopted architectures are also described with particular attention to
their relevance to ITER.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
A Study of the Radiative Ke3 Decay and Search for Direct Photon Emission with the KLOE Detector
We present a measurement of the ratio R =
\Gamma(\keg;\Estar>30\mev,\qstar>20^\circ)\Gamma(\kegf) of data corresponding to about 3.5
million Ke3(g) events and about 9000 radiative events. Our result is R=(924 +/-
23(stat) +/-16(syst)10^{-5} for the branching ratio and X=-2.3 +/- 1.3(stat)
+/- 1.4(syst) for the parameter describing direct emission.Comment: 8 pages, 7 figure
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