Fluctuations of fragment observables

This contribution presents a review of our present theoretical as well as experimental knowledge of different fluctuation observables relevant to nuclear multifragmentation. The possible connection between the presence of a fluctuation peak and the occurrence of a phase transition or a critical phenomenon is critically analyzed. Many different phenomena can lead both to the creation and to the suppression of a fluctuation peak. In particular, the role of constraints due to conservation laws and to data sorting is shown to be essential. From the experimental point of view, a comparison of the available fragmentation data reveals that there is a good agreement between different data sets of basic fluctuation observables, if the fragmenting source is of comparable size. This compatibility suggests that the fragmentation process is largely independent of the reaction mechanism (central versus peripheral collisions, symmetric versus asymmetric systems, light ions versus heavy ion induced reactions). Configurational energy fluctuations, that may give important information on the heat capacity of the fragmenting system at the freeze out stage, are not fully compatible among different data sets and require further analysis to properly account for Coulomb effects and secondary decays. Some basic theoretical questions, concerning the interplay between the dynamics of the collision and the fragmentation process, and the cluster definition in dense and hot media, are still open and are addressed at the end of the paper. A comparison with realistic models and/or a quantitative analysis of the fluctuation properties will be needed to clarify in the next future the nature of the transition observed from compound nucleus evaporation to multi-fragment production.Comment: Contribution to WCI (World Consensus Initiative) Book " "Dynamics and Thermodynamics with Nuclear Degrees of Freedom", to appear on Euorpean Physics Journal A as part of the Topical Volume. 9 pages, 12 figure

Tracking energy fluctuations from fragment partitions in the Lattice Gas model

Partial energy fluctuations are known tools to reconstruct microcanonical heat capacities. For experimental applications, approximations have been developed to infer fluctuations at freeze out from the observed fragment partitions. The accuracy of this procedure as well as the underlying independent fragment approximation is under debate already at the level of equilibrated systems. Using a well controlled computer experiment, the Lattice Gas model, we critically discuss the thermodynamic conditions under which fragment partitions can be used to reconstruct the thermodynamics of an equilibrated system.Comment: version accepted for publication in Phys.Rev.

Comment on "Partial energies fluctuations and negative heat capacities" by X. Campi et al

Studying the energy partioning published in nucl-th/0406056v2 we show that the presented results do not fulfill the sum rule due to energy conservation. The observed fluctuations of the energy conservation test point to a numerical problem. Moreover, analysis of the binding energies show that the fragment recognition algorithm adopted by Campi et al. leads with a sizeable probability to fragments containing up to the total mass even for excitation energies as large as 3/4 of the total binding. This surprising result points to another problem since the published inter-fragment energy is not zero while a unique fragment is present. This problem may be due to either the fragment recognition algorithm or to the definition of the inter and intra-fragment energy. These numerical inconsistencies should be settled before any conclusion on the physics can be drawn

L\u2019Italiano e l\u2019alfabeto per i nuovi arrivati

In recent years, thousands of refugees and asylum seekers have arrived at the port of Palermo, including a large number of teenagers without any adult caregivers. They are called Unaccompanied Minors. A significant part of them remain in the city and are placed in Italian language courses of the University of Palermo, (ItaStra), within a large inclusion project. The focus of this paper will be address to describe this new profile of learner: they are minors, 15 to 17 years old, without much formal education or training, without competent skills in reading or writing, but with a vast life experience in a multilingual environment and exposure to learning a diversity of new languages

"Chiamo uomo chi \ue8 padrone delle sue lingue". modelli di plurilinguismo da Lampedusa in su.

Il plurilinguismo dei nuovi migranti viene analizzato insieme al ruolo della lingua nella costruzione di modelli di societ\ue0 inclusiva e plural

Experimental Signals of Phase Transition

The connection between the thermodynamics of charged finite nuclear systems and the asymptotically measured partitions is presented. Some open questions, concerning in particular equilibrium partitions are discussed. We show a detailed comparison of the decay patterns in Au+ C,Cu,Au central collisions and in Au quasi-projectile events. Observation of abnormally large fluctuations in carefully selected samples of data is reported as an indication of a first order phase transition (negative heat capacity) in the nuclear equation of state.Comment: 8 pages, 8th International Conference on Nucleus-Nucleus Collisions, Moscow 200

The k0-INRIM software version 2.0: presentation and an analysis vademecum

The k0-INRIM software was developed at INRIM to perform k(0)-standardization Neutron Activation Analysis and evaluate combined uncertainty through application of the spreadsheet method. However, the presence of some limitation made its use, as a tool for routine NAA, impractical. With the aim to participate to the 2021 IAEA k(0)-NAA software intercomparison to evaluate the effect on mass fraction results due to software used, the k0-INRIM was sizably updated in order to meet the agreed functionality requirements to take part to the exercise. In this work, the version 2.0 of the software is presented and a point-by-point example analysis is displayed. The software version here described is available for download together with the corresponding updated user's manual

Healing Fair Dealing?: A Comparative Copyright Analysis of Canadian Fair Dealing to UK Fair Dealing and US Fair Use

As a result of the March 4, 2004 Supreme Court of Canada decision in CCH Canadian Ltd v Law Society of Upper Canada for the first time in Canadian copyright history, the court determined that Canadian law must recognize a user right to carry on exceptions generally and fair dealing in particular. This paper compares the Canadian fair dealing legislation and jurisprudence to that of the UK and the US. It is observed that because of CCH, the Canadian common law fair dealing factors are more flexible than those entrenched in the US. For the UK, certain criteria have emerged from the caselaw consonant to Canada\u27s pre-CCH framework and in many ways there is now a hierarchy of factors with market considerations at the fore. The real differences, however, ultimately lie in the policy preoccupations held by the respective courts, with Canada\u27s top court alone concerned in championing user rights above all other rights. The paper concludes that Canadian fair dealing does not require too much healing but would benefit from some remedies outside (and complementary to) the law and the courts. While doing nothing does not seem to be the appropriate response, legal intervention as many advocate may not be warranted either. Rather than, or at the very least together with, reforming the law, establishing fair dealing best practices is most promising. The parties directly affected in a specific industry can together develop these guidelines to ultimately aid in clearer and ongoing fairer fair dealing decision-making in the courts. It is here that US initiatives can serve as most fruitful to emulate

Self-attraction effect and correction on three absolute gravimeters

The perturbations of the gravitational field due to the mass distribution of an absolute gravimeter have been studied. The so called Self Attraction Effect (SAE) is crucial for the measurement accuracy, especially for the International Comparisons, and for the uncertainty budget evaluation. Three instruments have been analysed: MPG-2, FG5-238 and IMPG-02. The SAE has been calculated using a numerical method based on FEM simulation. The observed effect has been treated as an additional vertical gravity gradient. The correction (SAC) to be applied to the computed g value has been associated with the specific height level, where the measurement result is typically reported. The magnitude of the obtained corrections is of order 1E-8 m/s2.Comment: 14 pages, 8 figures, submitted to Metrologi