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Search Results: 1 - 10 of 429646 matches for " Antonio M. Lapenta "
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Functional Magnetic Resonance Imaging Demonstrates That Hypnosis Is Conscious and Voluntary  [PDF]
Edoardo Casiglia, Francesco Finatti, Federica Gasparotti, Maria Rosaria Stabile, Micaela Mitolo, Federica Albertini, Antonio M. Lapenta, Enrico Facco, Valérie Tikhonoff, Annalena Venneri
Psychology (PSYCH) , 2018, DOI: 10.4236/psych.2018.97095
Abstract: Hypnosis is a condition of modified consciousness (monoideism) resulting from a mental representation able to produce psychological and physical effects. The general belief is that hypnosis is conscious and voluntary, but the practical demonstration of this hypothesis is far to be demonstrated. Twenty healthy highly hypnotizable volunteers were studied during through functional magnetic resonance imaging during a task. The task was necessary because functional magnetic resonance imaging gives no interesting results in neutral hypnosis. During the hypnotic task, the prefrontal dorso-lateral cortex, genual cortex, dorsal anterior cingulate cortex, and orbital portion of the inferior frontal convolution (i.e. the Broadmann areas 9, 25, 32 and 47) were activated. Such areas are associated to egoic consciousness and voluntary processes. The results show that the hypothesis that hypnosis is conscious and voluntary is correct.
Granone’s Plastic Monoideism Demonstrated by Functional Magnetic Resonance Imaging (fMRI)  [PDF]
Edoardo Casiglia, Francesco Finatti, Valérie Tikhonoff, Maria R. Stabile, Micaela Mitolo, Federica Gasparotti, Federica Albertini, Antonio M. Lapenta, Annalena Venneri
Psychology (PSYCH) , 2019, DOI: 10.4236/psych.2019.104030
Abstract: Plastic monoideism is the supposed basis of hypnosis, but has never been experimentally demonstrated. The aim of the paper presented herein is to demonstrate that plastic monoideism exists and can be put in evidence by functional magnetic resonance (fMRI). To this aim, fMRI brain areas activation was examined in 20 highly hypnotizable young participants during a task represented by hypnotic analgesia. Inhibition of pain transmission from periphery to brain cortex was demonstrated during hypnotic analgesia by lack of activation of central somatosensory areas. At the same time, the Brodmann areas 9, 25, 32 and 47 were highly activated. This indicates that during a hypnotic task the iper-activity of certain brain areas inhibits the other ones. This is just, for the neurobiologist, what plastic monoideism is for the clinic hypnotist. The hyper-activated areas represent the physiological basis of the monoideism, which was therefore confirmed by brain imaging.
The Mysterious Hypnotic Analgesia: Experimental Evidences  [PDF]
Edoardo Casiglia, Edoardo Casiglia, Valérie Tikhonoff, Federica Albertini, Antonio M. Lapenta, Federica Gasparotti, Francesco Finatti, Augusto M. Rossi, Gastone Zanette, Margherita Giacomello, Nunzia Giordano, Jacopo Favaro, Enrico Facco
Psychology (PSYCH) , 2018, DOI: 10.4236/psych.2018.98112
Abstract: In the last years, the Laboratory of Experimental Hypnosis of the University of Padova and of the Institute Franco Granone of Torino, also in collaboration with the Foundation Hospital San Camillo in Venice, studied the effectiveness and the mechanisms of hypnotic analgesia in non-trigeminal an trigeminal pain. In this paper, the results of our work are summarized, starting from what was already known on the topic and exploring experimentally many different aspects of hypnotic analgesia. All the studies described in the present paper were conducted following scientific protocols and using the methods and means of Galilean science, employing in particular many instruments pertaining to human physiology and belonging to cardiology and neurology. This leads to the demonstration that hypnotic analgesia is an objective, real and measurable phenomenon.
Attractive Potential around a Thermionically Emitting Microparticle
G. L. Delzanno,G. Lapenta,M. Rosenberg
Physics , 2003, DOI: 10.1103/PhysRevLett.92.035002
Abstract: We present a simulation study of the charging of a dust grain immersed in a plasma, considering the effect of electron emission from the grain (thermionic effect). It is shown that the OML theory is no longer reliable when electron emission becomes large: screening can no longer be treated within the Debye-Huckel approach and an attractive potential well forms, leading to the possibility of attractive forces on other grains with the same polarity. We suggest to perform laboratory experiments where emitting dust grains could be used to create non-conventional dust crystals or macro-molecules.
Bipolar Electric Field Signatures of Reconnection Separatrices for a Hydrogen Plasma at Realistic Guide Fields
G. Lapenta,S. Markidis,A. Divin,M. Goldman,D. Newman
Physics , 2011, DOI: 10.1029/2011GL048572
Abstract: In preparation for the MMS mission we ask the question: how common are bipolar signatures linked to the presence of electron holes along separatrices emanating from reconnection regions? To answer this question, we conduct massively parallel simulations for realistic conditions and for the hydrogen mass ratio in boxes larger than considered in similar previous studies. The magnetic field configuration includes both a field reversal and a out of plane guide field, as typical of many space situations. The guide field is varied in strength from low values (typical of the Earth magnetotail) to high values comparable to the in plane reconnecting field (as in the magnetopause). In all cases, along the separatrices a strong electron flow is observed, sufficient to lead to the onset of streaming instabilities and to form bipolar parallel electric field signatures. The presence of bipolar structures at all guide fields allows the control of the MMS mission to consider the presence of bipolar signatures as a general flag of the presence of a nearby reconnection site both in the nightside and in the dayside of the magnetosphere.
Particle Control in Phase Space by Global K-Means Clustering
J. Trier Frederiksen,G. Lapenta,M. E. Pessah
Physics , 2015,
Abstract: We devise and explore an iterative optimization procedure for controlling particle populations in particle-in-cell (PIC) codes via merging and splitting of computational macro-particles. Our approach, is to compute an optimal representation of the global particle phase space structure while decreasing or increasing the entire particle population, based on k-means clustering of the data. In essence the procedure amounts to merging or splitting particles by statistical means, throughout the entire simulation volume in question, while minimizing a 6-dimensional total distance measure to preserve the physics. Particle merging is by far the most demanding procedure when considering conservation laws of physics; it amounts to lossy compression of particle phase space data. We demonstrate that our k-means approach conserves energy and momentum to high accuracy, even for high compression ratios, $\mathcal{R} \approx 3$ --- \emph{i.e.}, $N_{f} \lesssim 0.33N_{i}$. Interestingly, we find that an accurate particle splitting step can be performed using k-means as well; this from an argument of symmetry. The split solution, using k-means, places splitted particles optimally, to obtain maximal spanning on the phase space manifold. Implementation and testing is done using an electromagnetic PIC code, the \ppcode. Nonetheless, the k-means framework is general; it is not limited to Vlasov-Maxwell type PIC codes. We discuss advantages and drawbacks of this optimal phase space reconstruction.
Where should MMS look for electron diffusion regions?
G. Lapenta,M. Goldman,D. Newman,S. Markidis
Physics , 2015,
Abstract: A great possible achievement for the MMS mission would be crossing electron diffusion regions (EDR). EDR are regions in proximity of reconnection sites where electrons decouple from field lines, breaking the frozen in condition. Decades of research on reconnection have produced a widely shared map of where EDRs are. We expect reconnection to take place around a so called x-point formed by the intersection of the separatrices dividing inflowing from outflowing plasma. The EDR forms around this x-point as a small electron scale box nested inside a larger ion diffusion region. But this point of view is based on a 2D mentality. We have recently proposed that once the problem is considered in full 3D, secondary reconnection events can form [Lapenta et al., Nature Physics, 11, 690, 2015] in the outflow regions even far downstream from the primary reconnection site. We revisit here this new idea confirming that even using additional indicators of reconnection and even considering longer periods and wider distances the conclusion remains true: secondary reconnection sites form downstream of a reconnection outflow causing a sort of chain reaction of cascading reconnection sites. If we are right, MMS will have an interesting journey even when not crossing necessarily the primary site. The chances are greatly increased that even if missing a primary site during an orbit, MMS could stumble instead on one of these secondary sites.
Self-Feeding Turbulent Magnetic Reconnection on Macroscopic Scales
Giovanni Lapenta
Physics , 2008, DOI: 10.1103/PhysRevLett.100.235001
Abstract: Within a MHD approach we find magnetic reconnection to progress in two entirely different ways. The first is well-known: the laminar Sweet-Parker process. But a second, completely different and chaotic reconnection process is possible. This regime has properties of immediate practical relevance: i) it is much faster, developing on scales of the order of the Alfv\'en time, and ii) the areas of reconnection become distributed chaotically over a macroscopic region. The onset of the faster process is the formation of closed circulation patterns where the jets going out of the reconnection regions turn around and forces their way back in, carrying along copious amounts of magnetic flux.
The algorithms of the implicit moment method for plasma simulation
Giovanni Lapenta
Physics , 2008,
Abstract: We discuss the fundamentals of the implicit moment method for Particle In Cell (PIC) simulation as presently implemented in the CELESTE3D code. We present the method in its fully electromagnetic and fully kinetic version. The application of the method is to problems with multiple temporal and spatial scales, common in all space, astrophysical and laboratory plasmas.
Space Weather Prediction with Exascale Computing
Giovanni Lapenta
Physics , 2011,
Abstract: Space weather refers to conditions on the Sun, in the interplanetary space and in the Earth space environment that can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health. Adverse conditions in the space environment can cause disruption of satellite operations, communications, navigation, and electric power distribution grids, leading to a variety of socioeconomic losses. The conditions in space are also linked to the Earth climate. The activity of the Sun affects the total amount of heat and light reaching the Earth and the amount of cosmic rays arriving in the atmosphere, a phenomenon linked with the amount of cloud cover and precipitation. Given these great impacts on society, space weather is attracting a growing attention and is the subject of international efforts worldwide. We focus here on the steps necessary for achieving a true physics-based ability to predict the arrival and consequences of major space weather storms. Great disturbances in the space environment are common but their precise arrival and impact on human activities varies greatly. Simulating such a system is a grand- challenge, requiring computing resources at the limit of what is possible not only with current technology but also with the foreseeable future generations of super computers
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