Neutrino-pair bremsstrahlung by electrons in neutron star crusts

Neutrino-pair bremsstrahlung by relativistic degenerate electrons in a neutron-star crust at densities (10^9 - 1.5x10^{14}) g/cm^3 is analyzed. The processes taken into account are neutrino emission due to Coulomb scattering of electrons by atomic nuclei in a Coulomb liquid, and electron-phonon scattering and Bragg diffraction (the static-lattice contribution) in a Coulomb crystal. The static-lattice contribution is calculated including the electron band-structure effects for cubic Coulomb crystals of different types and also for the liquid crystal phases composed of rod- and plate-like nuclei in the neutron-star mantle (at 10^{14} - 1.5x10^{14} g/cm^3). The phonon contribution is evaluated with proper treatment of the multi-phonon processes which removes a jump in the neutrino bremsstrahlung emissivity at the melting point obtained in previous works. Below 10^{13} g/cm^3, the results are rather insensitive to the nuclear form factor, but results for the solid state near the melting point are affected significantly by the Debye-Waller factor and multi-phonon processes. At higher densities, the nuclear form factor becomes more significant. A comparison of the various neutrino generation mechanisms in neutron star crusts shows that electron bremsstrahlung is among the most important ones.Comment: 17 pages, 13 figures, LaTeX using aa.cls and epsf.sty. A&A, in pres

Theory of cooling neutron stars versus observations

We review current state of neutron star cooling theory and discuss the prospects to constrain the equation of state, neutrino emission and superfluid properties of neutron star cores by comparing the cooling theory with observations of thermal radiation from isolated neutron stars.Comment: 9 pages, 4 figures, 3 tables, to appear in the proceedings of "40 Years of Pulsars" held in Montreal, Canada, August 12-17, 2007, eds. C. Bassa, Z. Wang, A. Cumming, V. Kaspi, AIP, in press (v.2 - minor bibliography corrections

The direct evaluation of attosecond chirp from a streaking measurement

We derive an analytical expression, from classical electron trajectories in a laser field, that relates the breadth of a streaked photoelectron spectrum to the group-delay dispersion of an isolated attosecond pulse. Based on this analytical expression, we introduce a simple, efficient and robust procedure to instantly extract the attosecond pulse's chirp from the streaking measurement.Comment: 4 figure

Russian Manufacturing Revisited: Industrial Enterprises at the Start of the Crisis

The paper is based on the findings of a major project by the Higher School of Economics Institute for Industrial and Market Studies (IIMS) to monitor competitiveness of manufacturing enterprises. The study focuses on the drivers and dynamics of business competitiveness, including changes in firms’ behavior during the period before the crisis (2005-2008). The primary issue was to find out what firms and to what extent succeeded in capitalizing on the strong economic growth before the crisis to catch up with their competitors and gain a sustainable competitive position in the market. What was driving output increases and enhanced production efficiency? What were the impediments to this process

Cooling of Neutron Stars: Two Types of Triplet Neutron Pairing

We consider cooling of neutron stars (NSs) with superfluid cores composed of neutrons, protons, and electrons (assuming singlet-state pairing of protons, and triplet-state pairing of neutrons). We mainly focus on (nonstandard) triplet-state pairing of neutrons with the $|m_J| = 2$ projection of the total angular momentum of Cooper pairs onto quantization axis. The specific feature of this pairing is that it leads to a power-law (nonexponential) reduction of the emissivity of the main neutrino processes by neutron superfluidity. For a wide range of neutron critical temperatures $T_{cn}$, the cooling of NSs with the $|m_J| = 2$ superfluidity is either the same as the cooling with the $m_J = 0$ superfluidity, considered in the majority of papers, or much faster. The cooling of NSs with density dependent critical temperatures $T_{cn}(\rho)$ and $T_{cp}(\rho)$ can be imitated by the cooling of the NSs with some effective critical temperatures $T_{cn}$ and $T_{cp}$ constant over NS cores. The hypothesis of strong neutron superfluidity with $|m_J| = 2$ is inconsistent with current observations of thermal emission from NSs, but the hypothesis of weak neutron superfluidity of any type does not contradict to observations.Comment: 10 pages, 6 figure

Toward peripheral nerve mechanical characterization using Brillouin imaging spectroscopy

SIGNIFICANCE: Peripheral nerves are viscoelastic tissues with unique elastic characteristics. Imaging of peripheral nerve elasticity is important in medicine, particularly in the context of nerve injury and repair. Elasticity imaging techniques provide information about the mechanical properties of peripheral nerves, which can be useful in identifying areas of nerve damage or compression, as well as assessing the success of nerve repair procedures. AIM: We aim to assess the feasibility of Brillouin microspectroscopy for peripheral nerve imaging of elasticity, with the ultimate goal of developing a new diagnostic tool for peripheral nerve injury APPROACH: Viscoelastic properties of the peripheral nerve were evaluated with Brillouin imaging spectroscopy. RESULTS: An external stress exerted on the fixed nerve resulted in a Brillouin shift. Quantification of the shift enabled correlation of the Brillouin parameters with nerve elastic properties. CONCLUSIONS: Brillouin microscopy provides sufficient sensitivity to assess viscoelastic properties of peripheral nerves

Calibration of White Dwarf cooling sequences: theoretical uncertainty

White Dwarf luminosities are powerful age indicators, whose calibration should be based on reliable models. We discuss the uncertainty of some chemical and physical parameters and their influence on the age estimated by means of white dwarf cooling sequences. Models at the beginning of the white dwarf sequence have been obtained on the base of progenitor evolutionary tracks computed starting from the zero age horizontal branch and for a typical halo chemical composition (Z=0.0001, Y=0.23). The uncertainties due to nuclear reaction rates, convection, mass loss and initial chemical composition are discussed. Then, various cooling sequences for a typical white dwarf mass (M=0.6 Mo) have been calculated under different assumptions on some input physics, namely: conductive opacity, contribution of the ion-electron interaction to the free energy and microscopic diffusion. Finally we present the evolution of white dwarfs having mass ranging between 0.5 and 0.9 Mo. Much effort has been spent to extend the equation of state down to the low temperature and high density regime. An analysis of the latest improvement in the physics of white dwarf interiors is presented. We conclude that at the faint end of the cooling sequence (log L/Lo=-5.5) the present overall uncertainty on the age is of the order of 20%, which correspond to about 3 Gyr. We suggest that this uncertainty could be substantially reduced by improving our knowledge of the conductive opacity (especially in the partially degenerate regime) and by fixing the internal stratification of C and O.Comment: 14 figures, accepted by Ap

Efficiency of productivity potential realization of different-age sites of a trunk of grades of columnar type apple-trees

Received: April 15th, 2022 ; Accepted: May 15th, 2022 ; Published: May 17th, 2022 ; Correspondence: [email protected] article provides information about buds organogenesis in plants of columnar apple cultivars in the Forest-Steppe of Ukraine (Kyiv), which allows to establish the features of this process in complex fruit formations of different ages, and their productivity and longevity. We recommend studying of apple trees productivity in the process of its formation by analyzing of rudimentary organs formation and their consistent development into vegetative and generative organs, which are elements of productivity. Studies of organogenesis different-age fruit formations of columnar apple cultivars were conducted in the northern part of the Forest-Steppe of Ukraine during 2016–2020. It was established that separate age sections of columnar apple trees trunk formed different initial productivity potential. In plants of all studied varieties and age groups, the laying of generative buds, the implementation of reproductive elements in V–IX and X–XI stages of organogenesis were more effective in older age areas of the trunk. Complex fruit formations, regardless of the trunk age where they are placed, form a high potential for productivity, which is effectively realized. The dependence of the formation and productivity potential realization on the stages of organogenesis and meteorological factors is established