Comment on "Feynman Effective Classical Potential in the Schrodinger Formulation"

We comment on the paper "Feynman Effective Classical Potential in the Schrodinger Formulation"[Phys. Rev. Lett. 81, 3303 (1998)]. We show that the results in this paper about the time evolution of a wave packet in a double well potential can be properly explained by resorting to a variational principle for the effective action. A way to improve on these results is also discussed.Comment: 1 page, 2eps figures, Revte

Infrared spectroscopy of the largest known trans-neptunian object 2001 KX76

We report complete near-infrared (0.9-2.4 $\mu$m) spectral observations of the largest know trans-neptunian objects (TNO) 28976 = 2001 KX$_{76}$ taken in two different nights using the new Near Infrared Camera Spectrometer (NICS) attached to the 3.56m Telescopio Nazionale Galileo (TNG). The spectra are featureless and correspond to a neutral colored object. Our observations indicate that the surface of 2001 KX$_{76}$ is probably highly evolved due to long term irradiation, and that collisional resurfacing processes have not played an important role in its evolution.Comment: 1 Latex file, 2 postscript files. A&A in pres

The 16 November 2006 flank collapse of South-East Crater at Mount Etna, Italy: study of the deposit and hazard assessment

On 16 November 2006 a flank collapse affected the unstable Eastern slope of the South-East Crater 16 (SEC) of Mt. Etna. The collapse occurred during one of the paroxysmal events with sustained strombolian 17 activity that characterized the August-December 2006 eruption and was triggered by erosion of loose, 18 hydrothermally-altered material of the steep south-east sector of SEC from the outpour of lava. The collapse 19 produced a debris avalanche that involved both lithic and juvenile material and resulted in a deposit 20 emplaced on the Eastern flank of the volcano up to 1.2 km away from the source. The total volume of the 21 deposit was estimated to be in the order of 330,000-413,000 m3. The reconstruction of the collapse event 22 was simulated using TITAN2D, software designed to model granular avalanches and landslides. This 23 approach can be used to estimate areas that may be affected by similar collapse events in the future. The 24 area affected by the 16 November 2006 lateral collapse of SEC was a small portion of the Mt. Etna summit 25 area, but the fact that no one was killed or injured should be considered fortuitous. The summit and adjacent 26 areas of the volcano, in fact, are usually visited by many tourists who are not prepared to face this type of 27 danger. The 16 November 2006 collapse points to the need to be prepared for similar events through 28 scientific investigation (analysis of flank instability, numerical simulation of flows) and development of specific civil protection plans

Topological properties of the mean field phi^4 model

We study the thermodynamics and the properties of the stationary points (saddles and minima) of the potential energy for a phi^4 mean field model. We compare the critical energy Vc (i.e. the potential energy V(T) evaluated at the phase transition temperature Tc) with the energy V{theta} at which the saddle energy distribution show a discontinuity in its derivative. We find that, in this model, Vc >> V{theta}, at variance to what has been found in the literature for different mean field and short ranged systems. By direct calculation of the energy Vs(T) of the ``inherent saddles'', i.e. the saddles visited by the equilibrated system at temperature T, we find that Vs(Tc) ~ V{theta}. Thus, we argue that the thermodynamic phase transition is related to a change in the properties of the inherent saddles rather then to a change of the topology of the potential energy surface at T=Tc. Finally, we discuss the approximation involved in our analysis and the generality of our method.Comment: 14 pages, 9 figure

Seroepidemiology of Human Enterovirus 71 Infection among Children, Cambodia.

Enterovirus 71 is reported to have emerged in Cambodia in 2012; at least 54 children with severe encephalitis died during that outbreak. We used serum samples collected during 2000-2011 to show that the virus had been widespread in the country for at least a decade before the 2012 outbreak

INFN What Next: Ultra-relativistic Heavy-Ion Collisions

This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale di Fisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental study of the phase diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP) deconfined state will proceed, in the next 10-15 years, along two directions: the high-energy regime at RHIC and at the LHC, and the low-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the present and future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phase of high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity, there is a growing interest in a possible future experiment at the SPS, which would target the search for the onset of deconfinement using dimuon measurements. On a longer timescale, the community looks with interest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ion beams and on the Future Circular Collider.Comment: 99 pages, 56 figure

Improvement of ash plume monitoring, modeling and hazard assessment in the MED-SUV project

Volcanic ash clouds produced by explosive eruptions represent a strong problem for civil aviation, road transportation and other human activities. Since Etna volcano produced in the last 35 years more the 200 explosive eruptions of small and medium size. The INGV, liable for its volcano monitoring, developed since 2006 a specific system for forecasting and monitoring Etna’s volcanic ash plumes in collaboration with several national and international institutions. Between 12 January 2011 and 31 December 2013 Etna produced forty-six basaltic lava fountains. Every paroxysm produced an eruption column ranging from a few up to eleven kilometers of height above sea level. The ash cloud contaminated the controlled airspace (CTR) of Catania and Reggio Calabria airports and caused tephra fallout on eastern Sicily sometime disrupting the operations of these airports. In order to give prompt and detailed warnings to the Aviation and Civil Protection authorities, ash plumes monitoring at Osservatorio Etneo, the INGV department in Catania, is carried out using multispectral (from visible to infrared) satellite and ground-based video-surveillance images; seismic and infrasound signals processed in real-time, a Doppler RADAR (Voldorad IIB) able to detect the eruption column in all weather conditions and a LIDAR (AMPLE) for retrieving backscattering and depolarization values of the ash clouds. Forecasting is performed running tephra dispersal models using weather forecast data, and then plotting results on maps published on a dedicated website. 24/7 Control Room operators were able to timely nform Aviation and Civil Protection operators for an effective aviation safety management. A variety of multidisciplinary activities are planned in the MED-SUV project with reference to volcanic ash observations and studies. These include: 1) physical and analogue laboratory experiments on ash dispersal and aggregation; 2) integration of satellite data (e.g. METEOSAT, MODIS) and ground- based measurements (e.g., RADAR, LIDAR) of Etna’s volcanic plumes to quantify mass eruption rate, grain-size distribution at source, and ash cloud concentration; 3) improvement of tools and automatic procedures for the short-term forecasting of volcanic ash dispersal by adopting a multi-model and multi-scenario approach; 4) development of short-term forecasting tools able to use direct measurements of the plume and ash cloud in almost real time (now-casting); 5) development of long-term probabilistic ash fallout maps at the supersite volcanoes.PublishedVienna, Austria4V. Vulcani e ambienteope

Significant changes in the magma dynamics of Stromboli steady-state volcano recorded by clinopyroxene crystals.

&amp;lt;p&amp;gt;Steady-state volcanic activity implies equilibrium between the rate of magma replenishment and eruption of compositionally homogeneous magmas, lasting for tens to thousands of years in an open conduit system. The Present-day activity of Stromboli volcano (Aeolian Islands, Southern Italy) has long been recognised as typical of a steady-state volcano, with a shallow magmatic reservoir (highly porphyritic or hp-magma) continuously refilled by more mafic magma (with low phenocryst content or lp-magma) at a constant rate and accompanied by mixing, crystallisation and eruption. The lp-magma is erupted only during more violent explosive events (paroxysms), which usually occur at intervals of a few years. However, the two most recent paroxysms occurred at very short timescales on 3 July and 28 August 2019 offering the unique opportunity of obtaining crucial information on the current magma dynamics of Stromboli.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Albeit the plumbing system shows such uniformity, clinopyroxene phenocrysts exhibit marked chemical heterogeneities and complex textures caused by continuous lp-hp magma mixing as well as antecryst recycling from different mush portions. The compositional zoning in clinopyroxene provides essential information on pre-eruptive magma dynamics, indicating multi-stage crystallization across the lp-hp-reservoirs, where diopsidic compositions are markers of more primitive, high-T magmas injecting into shallow, low-T domains of the plumbing system. By comparing clinopyroxene texture, chemistry and residence times from the Present-day eruptions with the previous Post-Pizzo activity, we conclude that a distinct phase in the life of Stromboli volcano commenced after the violent 2003 paroxysm. Our observations suggest there are more efficient mechanisms of mush disruption and cannibalization, in which old diopsidic antecrysts are continuously remobilized and transported by the lp-magmas permeating the mush. The disappearance of diopsidic recharge bands within augitic overgrowths indicates that over time, magmatic injections feeding the persistent Present-day activity are more intensively mixed and homogenized prior to eruption.&amp;lt;/p&amp;gt; </jats:p

Quantifying probabilities of eruption at a well-monitored active volcano: an application to Mount Etna (Sicily, Italy).

At active volcanoes, distinct eruptions are preceded by complex and different precursory patterns; in addition, there are precursory signals which do not necessarily lead to an eruption. The main purpose of this paper is to present an unprecedented application of the recently developed code named BET_EF (Bayesian Event Tree_Eruption Forecasting) to the quantitative estimate of the eruptive hazard at Mt. Etna volcano. We tested the model for the case history of the July-August 2001 flank eruption. Anomalies in geophysical, geochemical and volcanological monitoring parameters were observed more than a month in advance of the effective onset of the eruption. As a consequence, eruption probabilities larger than 90% were estimated. An important feature of the application of BET_EF to Mt. Etna was the probabilistic estimate of opening vent locations. The methodology allowed a clear identification of assumptions and monitoring parameter thresholds and provided rational means for their revision if new data or information are incoming