Charged Particle Stopping Power Effects on Ignition: Some Results from an Exact Calculation

A completely rigorous first-principles calculation of the charged particle stopping power has recently been performed by Brown, Preston, and Singleton (BPS). This calculation is exact to leading and next-to-leading order in the plasma number density, including an exact treatment of two-body quantum scattering. The BPS calculation is therefore extremely accurate in the plasma regime realized during the ignition and burn of an inertial confinement fusion capsule. For deuterium-tritium fusion, the 3.5 MeV alpha particle range tends to be 20-30% longer than most models in the literature have predicted, and the energy deposition into the ions tends to be smaller. Preliminary numerical simulations indicate that this increases the rho-R required to achieve ignition.Comment: 19 pages, 3 Figures, Published in the proceedings for the 49th Annual meeting of the APS Division of Plasma Physics, Orlando FL, 12-16 November 2007. Added more details about numeric

Stochastic Approach to Enantiomeric Excess Amplification and Chiral Symmetry Breaking

Stochastic aspects of chemical reaction models related to the Soai reactions as well as to the homochirality in life are studied analytically and numerically by the use of the master equation and random walk model. For systems with a recycling process, a unique final probability distribution is obtained by means of detailed balance conditions. With a nonlinear autocatalysis the distribution has a double-peak structure, indicating the chiral symmetry breaking. This problem is further analyzed by examining eigenvalues and eigenfunctions of the master equation. In the case without recycling process, final probability distributions depend on the initial conditions. In the nonlinear autocatalytic case, time-evolution starting from a complete achiral state leads to a final distribution which differs from that deduced from the nonzero recycling result. This is due to the absence of the detailed balance, and a directed random walk model is shown to give the correct final profile. When the nonlinear autocatalysis is sufficiently strong and the initial state is achiral, the final probability distribution has a double-peak structure, related to the enantiomeric excess amplification. It is argued that with autocatalyses and a very small but nonzero spontaneous production, a single mother scenario could be a main mechanism to produce the homochirality.Comment: 25 pages, 6 figure

Disordered Fulde-Ferrel-Larkin-Ovchinnikov State in d-wave Superconductors

We study the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) superconducting state in the disordered systems. We analyze the microscopic model, in which the d-wave superconductivity is stabilized near the antiferromagnetic quantum critical point, and investigate two kinds of disorder, namely, box disorder and point disorder, on the basis of the Bogoliubov-deGennes (BdG) equation. The spatial structure of modulated superconducting order parameter and the magnetic properties in the disordered FFLO state are investigated. We point out the possibility of "FFLO glass" state in the presence of strong point disorders, which arises from the configurational degree of freedom of FFLO nodal plane. The distribution function of local spin susceptibility is calculated and its relation to the FFLO nodal plane is clarified. We discuss the NMR measurements for CeCoIn_5.Comment: Submitted to New. J. Phys. a focus issue on "Superconductors with Exotic Symmetries

Observer Dependent Horizon Temperatures: a Coordinate-Free Formulation of Hawking Radiation as Tunneling

We reformulate the Hamilton-Jacobi tunneling method for calculating Hawking radiation in static, spherically-symmetric spacetimes by explicitly incorporating a preferred family of frames. These frames correspond to a family of observers tied to a locally static timelike Killing vector of the spacetime. This formulation separates the role of the coordinates from the choice of vacuum and thus provides a coordinate-independent formulation of the tunneling method. In addition, it clarifies the nature of certain constants and their relation to these preferred observers in the calculation of horizon temperatures. We first use this formalism to obtain the expected temperature for a static observer at finite radius in the Schwarzschild spacetime. We then apply this formalism to the Schwarzschild-de Sitter spacetime, where there is no static observer with 4-velocity equal to the static timelike Killing vector. It is shown that a preferred static observer, one whose trajectory is geodesic, measures the lowest temperature from each horizon. Furthermore, this observer measures horizon temperatures corresponding to the well-known Bousso-Hawking normalization.Comment: 11 pages, 1 2-part figure, references added, appendix added, discussion streamline

Two-body Cabibbo-suppressed Decays of Charmed Baryons into Vector Mesons and into Photons

The heavy quark effective theory and the factorization approximation are used to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons, $\Lambda_C\rightarrow p{\rho^0}, p\omega$, $\Xi_C^{+,0}\rightarrow\Sigma^{+,0}\phi, \Sigma^{+,0}{\rho^0}, \Sigma^{+,0}\omega$ and $\Xi_C^{0}\rightarrow\Lambda\phi, \Lambda\rho, \Lambda\omega$. The input from two recent experimental results on $\Lambda_C$ decays allows the estimation of the branching ratios for these modes, which turn out to be between $10^{-4}$ and $10^{-3}$. The long distance contribution of these transitions via vector meson dominance to the radiative weak processes $\Lambda_C\rightarrow p\gamma$, $\Xi_C\rightarrow\Sigma\gamma$ and $\Xi_C^0\rightarrow\Lambda\gamma$ leads to quite small branching ratios, $10^{-6}-10^{-9}$; the larger value holds if a sum rule between the coupling constants of the vector mesons is broken.Comment: 11 pages, latex, no figure

Variation of almond yield, biometry, α-tocopherol levels, and antioxidant properties with nitrogen fertilization

A two years’ experiment (2015–2016) was set in a factorial design in which the effect of two application forms of nitrogen (N) (soil and soil + foliar spray) in different doses (0, 25, 50, and 100 kg N ha-1) on almond (Prunus dulcis Mill. cv. “Masbovera”) was evaluated. Kernel yield, biometric properties, phytochemicals, and antioxidant activities were assessed. The results showed that almond kernel yield increases with an increment in N rate doses and was positively correlated with kernel weight and thickness, and negatively with fruit weight. The levels of α-tocopherol and total polyphenol content were higher with lower N doses (25 and 50 kg N ha–1). The antioxidant activities were positively correlated with polyphenol content. Based on our results, excessive N rates over 50 kg/ha depreciate the levels of α-tocopherol, total polyphenols, and antioxidant bioactivities of kernels. Practical applications Almond is an important nut (dry) fruit that contains high levels of α-tocopherol, moderate levels of polyphenols, and high antioxidant activities, all responsible for their claimed health-promoting properties. Almond trees are known by their alternate behavior in which kernel yield and levels of phytochemicals and other compounds are highly variable between years. This article studies the usage of a sustainable nitrogen fertilization program toward a reduction of their alternate behavior, preserving and promoting their antioxidant properties and their levels of phytochemicals, particularly α-tocopherol and polyphenols. Our findings may provide a useful guide for adequate nitrogen fertilization program toward a better almond kernel qualityinfo:eu-repo/semantics/publishedVersio