545 research outputs found
Numerical solution of the Boltzmann equation for the collective modes of trapped Fermi gases
We numerically solve the Boltzmann equation for trapped fermions in the
normal phase using the test-particle method. After discussing a couple of tests
in order to estimate the reliability of the method, we apply it to the
description of collective modes in a spherical harmonic trap. The numerical
results are compared with those obtained previously by taking moments of the
Boltzmann equation. We find that the general shape of the response function is
very similar in both methods, but the relaxation time obtained from the
simulation is significantly longer than that predicted by the method of
moments. It is shown that the result of the method of moments can be corrected
by including fourth-order moments in addition to the usual second-order ones
and that this method agrees very well with our numerical simulations.Comment: 13 pages, 8 figures, accepted for publication in Phys. Rev.
Thermalisation time and specific heat of neutron stars crust
We discuss the thermalisation process of the neutron stars crust described by
solving the heat transport equation with a microscopic input for the specific
heat of baryonic matter. The heat equation is solved with initial conditions
specific to a rapid cooling of the core. To calculate the specific heat of
inner crust baryonic matter, i.e., nuclear clusters and unbound neutrons, we
use the quasiparticle spectrum provided by the Hartree-Fock-Bogoliubov approach
at finite temperature. In this framework we analyse the dependence of the crust
thermalisation on pairing properties and on cluster structure of inner crust
matter. It is shown that the pairing correlations reduce the crust
thermalisation time by a very large fraction. The calculations show also that
the nuclear clusters have a non-negligible influence on the time evolution of
the surface temperature of the neutron star.Comment: 7 pages, 5 figures, submitted to Phys. Rev.
The iconography of Asphyxiophilia: From fantasmatic fetish to forensic fact
This is a post print version of the article. The official published version can be accessed from the link below
Changes in plant growth, leaf relative water content and physiological traits in response to salt stress in peanut (Arachis hypogaea L.) varieties
Salinity is the main environmental factor accountable for decreasing crop productivity worldwide. The effects of NaCl salinity on plant growth (leaf relative water content (RWC), leaf dry weight (LDW), shoot length (SL), number of leaves (NL), number of branches (NB) and total leaf area (TLA) and physiological characteristics (stomatal conductance (gs), transpiration rate (TR), net photosynthetic (Pn), yield of photosystem II (ΦPsII) and the intercellular CO2 concentration (CO2int) in peanut (Arachis hypogaea L.) varieties (‘Vanda’, ‘P244601’ and ‘Pl184948’, widely used in Cameroon, Tanzania and Ghana, respectively, were investigated under hydroponic condition. Plants were subjected to four levels of NaCl (0, 40, 80 and 120 mM) at early seedling growth stage of plant development. Application of NaCl treatment led to a significant decrease in LDW, SL, NL, TLA, Pn, gs, TR and CO2int concentration of ‘Vanda’ and ‘P244601’ compared to untreated plants while the plant growth inhibition was notably noted at 120 mM NaCl in ‘P1184948’ for LDW, SL and NB. The highest depressive effect was detected in gs of salt-sensitive ‘Vanda’ while the lowest were recorded in gs of salt-tolerant ‘P1184948’ at high salinity level. Enhanced NaCl concentrations led to a significant increase in ΦPSII of ‘P1184948’ compared to ‘Vanda’, ‘P244601’ and untreated plants. Leaf CHL content was significantly increased in moderately-tolerant ‘‘P244601’ and salt-tolerant ‘P1184948’ at 80 mM NaCl compared to salt sensitive ‘Vanda’ and untreated plants. The depressive effect of salt on RWC was recorded at 120 mM NaCl in peanut leaves of all varieties. Under salt stress ‘P1184948’ was observed to have relatively higher tolerance on average of all growth and physiological traits than ‘Vanda’ and P244601’ suggesting that it could be grown in salt-affected soils
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