Interstellar MHD Turbulence and Star Formation

This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling processes that control its thermodynamic behavior. The turbulence in the warm and hot ionized components of the ISM appears to be trans- or subsonic, and thus to behave nearly incompressibly. However, the neutral warm and cold components are highly compressible, as a consequence of both thermal instability in the atomic gas and of moderately-to-strongly supersonic motions in the roughly isothermal cold atomic and molecular components. Within this context, we discuss: i) the production and statistical distribution of turbulent density fluctuations in both isothermal and polytropic media; ii) the nature of the clumps produced by thermal instability, noting that, contrary to classical ideas, they in general accrete mass from their environment; iii) the density-magnetic field correlation (or lack thereof) in turbulent density fluctuations, as a consequence of the superposition of the different wave modes in the turbulent flow; iv) the evolution of the mass-to-magnetic flux ratio (MFR) in density fluctuations as they are built up by dynamic compressions; v) the formation of cold, dense clouds aided by thermal instability; vi) the expectation that star-forming molecular clouds are likely to be undergoing global gravitational contraction, rather than being near equilibrium, and vii) the regulation of the star formation rate (SFR) in such gravitationally contracting clouds by stellar feedback which, rather than keeping the clouds from collapsing, evaporates and diperses them while they collapse.Comment: 43 pages. Invited chapter for the book "Magnetic Fields in Diffuse Media", edited by Elisabete de Gouveia dal Pino and Alex Lazarian. Revised as per referee's recommendation

Strangeness nuclear physics: a critical review on selected topics

Selected topics in strangeness nuclear physics are critically reviewed. This includes production, structure and weak decay of $\Lambda$--Hypernuclei, the $\bar K$ nuclear interaction and the possible existence of $\bar K$ bound states in nuclei. Perspectives for future studies on these issues are also outlined.Comment: 63 pages, 51 figures, accepted for publication on European Physical Journal

POSSIBLE IMPROVEMENTS OF MÖSSBAUER SPECTROMETERS WITH THE USE OF MULTIWIRE PROPORTIONAL COUNTERS

Nous discutons les caractéristiques d'un spectromètre Mössbauer construit en utilisant une chambre proportionnelle multifils. La résolution en vitesse et l'efficacité de détection pour rayons γ sont analysées. Détails de construction et résultats expérimentaux sont reportés.We describe Mössbauer spectrometer utilizing a multiwire proportional chamber. Velocity resolution and detection efficiency for γ-rays are discussed. Details of construction and experimental results are given

A large-area neutron detector based on double scattering

The performance of a detector designed for measuring the energy of neutrons emitted during a cold-fusion experiment is described. It is based on the operating principle of neutron double scattering in two different scintillator arrays; the results obtained from a calibration with a 241AmBe neutron source in terms of efficiency, energy spectrum reconstruction and background rejection capabilities are reported