2,911 research outputs found

    The MAGNEX spectrometer: results and perspectives

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    This article discusses the main achievements and future perspectives of theMAGNEX spectrometer at the INFN-LNS laboratory in Catania (Italy). MAGNEX is alarge acceptance magnetic spectrometer for the detection of the ions emitted innuclear collisions below Fermi energy. In the first part of the paper anoverview of the MAGNEX features is presented. The successful application to theprecise reconstruction of the momentum vector, to the identification of the ionmasses and to the determination of the transport efficiency is demonstrated byin-beam tests. In the second part, an overview of the most relevant scientificachievements is given. Results from nuclear elastic and inelastic scattering aswell as from transfer and charge exchange reactions in a wide range of massesof the colliding systems and incident energies are shown. The role of MAGNEX insolving old and new puzzles in nuclear structure and direct reaction mechanismsis emphasized. One example is the recently observed signature of the longsearched Giant Pairing Vibration. Finally, the new challenging opportunities touse MAGNEX for future experiments are briefly reported. In particular, the useof double charge exchange reactions toward the determination of the nuclearmatrix elements entering in the expression of the half-life of neutrinolessdouble beta decay is discussed. The new NUMEN project of INFN, aiming at theseinvestigations, is introduced. The challenges connected to the major technicalupgrade required by the project in order to investigate rare processes underhigh fluxes of detected heavy ions are outlined

    A view of recent results and perspectives on nuclear structure with MAGNEX at the INFN-LNS laboratory

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    An intense activity in the field of experimental, as well as theoretical, nuclear structure is ongoing at the INFN-LNS laboratory in Catania. A short overview of the main recent results is reported

    POSTNATAL DEVELOPMENTAL CHANGES IN ENTERIC DOPAMINERGIC SYSTEM

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    The postnatal period is a key period of life, characterized by the maturation of various organs and in particular of the gut. Currently, we have a poor understanding of the development of neurological and endocrine factors that control intestinal motility. Such knowledge can provide indications about the potency, efficacy, or therapeutic range of a drug in premature infants. Dopaminegic antagonists are often used as prokinetic drugs to treat impaired GI propulsion, although the role of the enteric dopaminergic system in the control of intestinal motility in neonatal vs adult has not been adequately addressed. In this view the aim of this study, was to examine, the functionality of the dopaminergic systems in the regulation of duodenal contractility in neonatal vs adult, using a murine animal model. Transcripts for all dopaminergic receptors (D1-like family, D1 and D5 receptors, and D2-like family, D2, D3, and D4 receptors) can be detected in mouse gut at each age. Mechanical responses to dopamine (DA) were examined in vitro in duodenal longitudinal muscle from postnatal and adult mice as changes in isometric tension. In neonatal duodenum, DA evoked a TTX-insensitive muscular contraction, reduced by SCH 23390, D1-like receptor antagonist, but not by domperidone, D2-like receptor antagonist, and mimicked by a D1 receptor agonist. The contractile response to DA decreased in intensity with age and in adults, in its place, a distinct TTX-insensitive muscular relaxation was detected. Inhibitory response to DA was mimicked by D1 or D2 receptor agonists and reduced by domperidone, and, to a lesser extent, by SCH 23390. In neonatal mice the excitatory responses mediated by D1 receptor activation were antagonized by U-73122, phospholipase C (PLC) inhibitor, whilst in adults the inhibitory effects were blocked by DDA, adenylyl cyclase inhibitor. In mouse gut, dopaminergic transmission undergoes to postnatal change in the pattern of receptor functionality. In postnatal period, DA leads to muscular contraction exclusively via D1-like receptors, likely D5 receptors, linked to activation of PLC. In adults, DA is able to relax duodenum recruiting D2 receptors and shifting the effects mediated by D1-like receptors, likely D1 receptors, activating cAMP pathway

    Exploring how to use virtual tours to create an interactive customer remote experience

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    This paper investigates the use of Virtual Reality (VR) to develop virtual tour applications for marketing purposes. The aim is to explore how virtual technologies can support the creation of knowledge about a specific food product and the achievement of user engagement by a multi-sensory virtual tour of the real production site. The study provides design guidelines to create a valuable, multisensory experience by VR tours and demonstrate how the adoption of a user-driven approach, instead of a technology-driven approach, allows to achieve a positive intention to buy. The case study was represented by one of the excellences among Italian food products, the Parmigiano Reggiano (PR) cheese. The PR virtual tour was validated by a user testing campaign, involving more than 70 users: users' reactions and feedback were collected by human physiological data monitoring and questionnaires' administration. The research results demonstrated how virtual technologies could effectively help people to create a solid knowledge about a food product to support the marketing process and to form an intention to buy thanks to a better understanding of the quality of the local and traditional productions

    Microscopic cluster model for the description of (18O,16O) two-neutron transfer reactions

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    Excitation energy spectra and absolute cross-section angular distributions were measured for the 13C(18O,16O)15C two-neutron transfer reaction at 84 MeV incident energy. Exact finite-range coupled reaction channel calculations are used to analyse the data considering both the direct two-neutron transfer and the two-step sequential mechanism. For the direct calculations, two approaches are discussed: The extreme cluster and the newly introduced microscopic cluster. The latter makes use of spectroscopic amplitudes in the centre-of-mass reference frame, derived from shell-model calculations. The results describe well the experimental cross sections

    3D sensors for the HL-LHC

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    In order to increase its discovery potential, the Large Hadron Collider (LHC) accelerator will be upgraded in the next decade. The high luminosity LHC (HL-LHC) period demands new sensor technologies to cope with increasing radiation fluences and particle rates. The ATLAS experiment will replace the entire inner tracking detector with a completely new silicon-only system. 3D pixel sensors are promising candidates for the innermost layers of the Pixel detector due to their excellent radiation hardness at low operation voltages and low power dissipation at moderate temperatures. Recent developments of 3D sensors for the HL-LHC are presented.Comment: 8 pages, 5 figures, International Workshops on Radiation Imaging Detectors 201

    Characterisation of AMS H35 HV-CMOS monolithic active pixel sensor prototypes for HEP applications

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    Monolithic active pixel sensors produced in High Voltage CMOS (HV-CMOS) technology are being considered for High Energy Physics applications due to the ease of production and the reduced costs. Such technology is especially appealing when large areas to be covered and material budget are concerned. This is the case of the outermost pixel layers of the future ATLAS tracking detector for the HL-LHC. For experiments at hadron colliders, radiation hardness is a key requirement which is not fulfilled by standard CMOS sensor designs that collect charge by diffusion. This issue has been addressed by depleted active pixel sensors in which electronics are embedded into a large deep implantation ensuring uniform charge collection by drift. Very first small prototypes of hybrid depleted active pixel sensors have already shown a radiation hardness compatible with the ATLAS requirements. Nevertheless, to compete with the present hybrid solutions a further reduction in costs achievable by a fully monolithic design is desirable. The H35DEMO is a large electrode full reticle demonstrator chip produced in AMS 350 nm HV-CMOS technology by the collaboration of Karlsruher Institut f\"ur Technologie (KIT), Institut de F\'isica d'Altes Energies (IFAE), University of Liverpool and University of Geneva. It includes two large monolithic pixel matrices which can be operated standalone. One of these two matrices has been characterised at beam test before and after irradiation with protons and neutrons. Results demonstrated the feasibility of producing radiation hard large area fully monolithic pixel sensors in HV-CMOS technology. H35DEMO chips with a substrate resistivity of 200Ω\Omega cm irradiated with neutrons showed a radiation hardness up to a fluence of 101510^{15}neq_{eq}cm2^{-2} with a hit efficiency of about 99% and a noise occupancy lower than 10610^{-6} hits in a LHC bunch crossing of 25ns at 150V

    Microscopic cluster model for the description of new experimental results on the C 13 (O 18, O 16) C 15 two-neutron transfer at 84 MeV incident energy

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    The C13(O18,O16)C15 reaction is studied at 84 MeV incident energy. Excitation energy spectra and absolute cross-section angular distributions for the strongest transitions are measured with good energy and angular resolutions. Strong selectivity for two-neutron configurations in the states of the residual nucleus is found. The measured cross-section angular distributions are analyzed by exact finite-range coupled reaction channel calculations. The two-particle wave functions are extracted using the extreme cluster and the independent coordinate scheme with shell-model derived coupling strengths. A new approach also is introduced, the microscopic cluster, in which the spectroscopic amplitudes in the center-of-mass reference frame are derived from shell-model calculations using the Moshinsky transformation brackets. This new model is able to describe well the experimental cross section and to highlight cluster configurations in the involved wave functions

    The polarization mode of the auroral radio emission from the early-type star HD142301

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    We report the detection of the auroral radio emission from the early-type magnetic star HD142301. New VLA observations of HD142301 detected highly polarized amplified emission occurring at fixed stellar orientations. The coherent emission mechanism responsible for the stellar auroral radio emission amplifies the radiation within a narrow beam, making the star where this phenomenon occurs similar to a radio lighthouse. The elementary emission process responsible for the auroral radiation mainly amplifies one of the two magneto-ionic modes of the electromagnetic wave. This explains why the auroral pulses are highly circularly polarized. The auroral radio emission of HD142301 is characterized by a reversal of the sense of polarization as the star rotates. The effective magnetic field curve of HD142301 is also available making it possible to correlate the transition from the left to the right-hand circular polarization sense (and vice-versa) of the auroral pulses with the known orientation of the stellar magnetic field. The results presented in this letter have implications for the estimation of the dominant magneto-ionic mode amplified within the HD142301 magnetosphere.Comment: 5 pages, 4 figures; accepted to MNRAS Letter
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