This book tells the curious story of an unexpected finding that sheds light on a crucial moment in the development of physics: the discovery of artificial radioactivity induced by neutrons. The finding in question is a notebook, clearly written in Fermi's handwriting, which records the frenzied days and nights that Fermi spent experimenting alone, driven by his theoretical ideas on beta decay. The notebook was found by the authors while browsing through documents left by Oscar D'Agostino, the chemist among Fermi's (...) group. From Fermi's notes, they reconstruct with skill and expertise the detailed timeline of the critical days leading up to his vital discovery. While much is already known about the road that led Fermi to his important result, this is the first time that it has been possible to reconstruct precisely when and how the initial evidence of neutron-induced decay was obtained. In relating this fascinating story, the book will be of great interest not only to those with a passion for the history of science but also to a wider audience. (shrink)

In this paper we reconsider, in the light of the Nelson stochastic mechanics, the idea originally proposed by Bohm and Vigier that arbitrary solutions of the evolution equation for the probability densities always relax in time toward the quantum mechanical density ¦ψ¦2 derived from the Schrödinger equation. The analysis of a few general propositions and of some physical examples show that the choice of the L1 metrics and of the Nelson stochastic flux is correct for a particular class of quantum (...) states, but cannot be adopted in general. This indicates that the question if the quantum mechanical densities attract other solution of the classical Fokker-Planck equations associated to the Schrödinger equation is physically meaningful, even if a classical probabilistic model good for every quantum stale is still not available. A few suggestion in this direction are finally discussed. (shrink)

Aim of the study was to analyze the posttraumatic stress disorder risk nurses, detecting the relationship between distress experience and personality dimensions in Italian COVID-19 outbreak. A cross-sectional study was conducted based on 2 data detection. Mental evaluation was carried out in Laboratory of Clinical Psychology on n.69 nurses in range age 22–64 years old. Measurement was focused on symptoms anxiety, personality traits, peritraumatic dissociation and post-traumatic stress for all participants. No online screening was applied. Comparisons within the various demographic (...) characteristics demonstrated few significant differences between groups on DASS-21, PDEQ, and ISE-R scores. Correlation analysis was performed among PDEQ, DASS-21, BFI-10 and IES-R and confirmed between anxiety and peritraumatic dissociation and post-traumatic stress; then anxiety is positively correlated to agreeableness variable of BFI-10 test. The emotional distress was protracted overtime but in long-term personality traits resulted mediator facing subjective stress. Our finding drew details for protective and predictive risk factors as well as mental health issues of nurses dealing with pandemic: healthcare workers faced the protracted challenge caring COVID-19 patients over and over again: in short time the impact was relevant, and the prolonged exposition to the stressor was tackled by personal resources such as personality traits. (shrink)