44,129 research outputs found

    The Human Development Index Adjusted for Efficient Resource Utilization

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    human development index, data envelopment analysis, efficiency, congestion and scale economics

    An introductory note on Quasicrystals

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    This paper presents a brief introduction of the research on a new class of materials called quasicrystals. Starting from history of its development, paper discusses about its growth mechanism and its applications. Contents of the paper are based on various sources available and no originality of the article is claimed by the author

    Sarcoma immunotherapy.

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    Much of our knowledge regarding cancer immunotherapy has been derived from sarcoma models. However, translation of preclinical findings to bedside success has been limited in this disease, though several intriguing clinical studies hint at the potential efficacy of this treatment modality. The rarity and heterogeneity of tumors of mesenchymal origin continues to be a challenge from a therapeutic standpoint. Nonetheless, sarcomas remain attractive targets for immunotherapy, as they can be characterized by specific epitopes, either from their mesenchymal origins or specific alterations in gene products. To date, standard vaccine trials have proven disappointing, likely due to mechanisms by which tumors equilibrate with and ultimately escape immune surveillance. More sophisticated approaches will likely require multimodal techniques, both by enhancing immunity, but also geared towards overcoming innate mechanisms of immunosuppression that favor tumorigenesis

    Turbulence and Mixing in the Intracluster Medium

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    The intracluster medium (ICM) is stably stratified in the hydrodynamic sense with the entropy ss increasing outwards. However, thermal conduction along magnetic field lines fundamentally changes the stability of the ICM, leading to the "heat-flux buoyancy instability" when dT/dr>0dT/dr>0 and the "magnetothermal instability" when dT/dr<0dT/dr<0. The ICM is thus buoyantly unstable regardless of the signs of dT/drdT/dr and ds/drds/dr. On the other hand, these temperature-gradient-driven instabilities saturate by reorienting the magnetic field (perpendicular to r^\hat{\bf r} when dT/dr>0dT/dr>0 and parallel to r^\hat{\bf r} when dT/dr<0dT/dr<0), without generating sustained convection. We show that after an anisotropically conducting plasma reaches this nonlinearly stable magnetic configuration, it experiences a buoyant restoring force that resists further distortions of the magnetic field. This restoring force is analogous to the buoyant restoring force experienced by a stably stratified adiabatic plasma. We argue that in order for a driving mechanism (e.g, galaxy motions or cosmic-ray buoyancy) to overcome this restoring force and generate turbulence in the ICM, the strength of the driving must exceed a threshold, corresponding to turbulent velocities ≳10−100km/s\gtrsim 10 -100 {km/s}. For weaker driving, the ICM remains in its nonlinearly stable magnetic configuration, and turbulent mixing is effectively absent. We discuss the implications of these findings for the turbulent diffusion of metals and heat in the ICM.Comment: 8 pages, 2 figs., submitted to the conference proceedings of "The Monster's Fiery Breath;" a follow up of arXiv:0901.4786 focusing on the general mixing properties of the IC

    Unified equation of state for neutron stars on a microscopic basis

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    We derive a new equation of state (EoS) for neutron stars (NS) from the outer crust to the core based on modern microscopic Brueckner-Hartree-Fock (BHF) calculations using the Argonne v18v_{18} potential plus three-body forces computed with the Urbana model. To deal with the inhomogeneous structures of matter in the NS crust, we use the recent Barcelona-Catania-Paris-Madrid (BCPM) nuclear energy density functional that is directly based on the same microscopic BHF calculations, and which is able to reproduce the ground-state properties of nuclei along the periodic table. The EoS of the outer crust requires the masses of neutron-rich nuclei, which are obtained through Hartree-Fock-Bogoliubov calculations with the BCPM functional when they are unknown experimentally. To compute the inner crust, Thomas-Fermi calculations in Wigner-Seitz cells are performed with the same functional. Existence of nuclear pasta is predicted in a range of average baryon densities between ≃\simeq0.067 fm−3^{-3} and ≃\simeq0.0825 fm−3^{-3}, where the transition to the core takes place. The NS core is computed from the nuclear EoS of the BHF calculation assuming non-exotic constituents (core of npeμnpe\mu matter). In each region of the star, we discuss the comparison of the new EoS with previous EoSes for the complete NS structure, in particular, with the Lattimer-Swesty EoS and with the Shen et al. EoS widely used in astrophysical calculations. The new microscopically derived EoS fulfills at the same time a NS maximum mass of 2~M⊙M_\odot with a radius of 10 km, and a 1.5~M⊙M_\odot NS with a radius of 11.7 km.Comment: 23 pages, 17 figures, revised version accepted for publication in Astronomy & Astrophysic

    The nuclear shell effects near the r-process path in the relativistic Hartree-Bogoliubov theory

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    We have investigated the evolution of the shell structure of nuclei in going from the r-process path to the neutron drip line within the framework of the Relativistic Hartree-Bogoliubov (RHB) theory. By introducing the quartic self-coupling of ω\omega meson in the RHB theory in addition to the non-linear scalar coupling of σ\sigma meson, we reproduce the available data on the shell effects about the waiting-point nucleus 80^{80}Zn. With this approach, it is shown that the shell effects at N=82 in the inaccessible region of the r-process path become milder as compared to the Lagrangian with the scalar self-coupling only. However, the shell effects remain stronger as compared to the quenching exhibited by the HFB+SkP approach. It is also shown that in reaching out to the extreme point at the neutron drip line, a terminal situation arises where the shell structure at the magic number is washed out significantly.Comment: 18 pages (revtex), 8 ps figures, to appear in Phys. Rev.
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