Modified Korteweg-de Vries Hierachies in Multiple-Times Variables and the Solutions of Modified Boussinesq Equations

We study solitary-wave and kink-wave solutions of a modified Boussinesq equation through a multiple-time reductive perturbation method. We use appropriated modified Korteweg-de Vries hierarchies to eliminate secular producing terms in each order of the perturbative scheme. We show that the multiple-time variables needed to obtain a regular perturbative series are completely determined by the associated linear theory in the case of a solitary-wave solution, but requires the knowledge of each order of the perturbative series in the case of a kink-wave solution. These appropriate multiple-time variables allow us to show that the solitary-wave as well as the kink-wave solutions of the modified Botussinesq equation are actually respectively a solitary-wave and a kink-wave satisfying all the equations of suitable modified Korteweg-de Vries hierarchies.Comment: RevTex file, submitted to Proc. Roy. Soc. London

The Potassium abundance in the globular clusters NGC104, NGC6752 and NGC6809

We derived Potassium abundances in red giant branch stars in the Galactic globular clusters NGC104 (144 stars), NGC6752 (134 stars) and NGC6809 (151 stars) using high-resolution spectra collected with FLAMES at the ESO - Very Large Telescope. In the considered samples we do not find significant intrinsic spreads in [K/Fe] (confirming the previous findings by Carretta et al.), at variance with the cases of the massive clusters NGC2419 and NGC2808. Additionally, marginally significant [K/Fe]-[O/Fe] anti-correlations are found in NGC104 and NGC6809, and [K/Fe]-[Na/Fe] correlations are found in NGC104 and NGC6752. No evidence of [K/Fe]-[Mg/Fe] anti-correlation are found. The results of our analysis are consistent with a scenario in which the process leading to the multi-populations in globular clusters implies also enrichment in the K abundance, the amplitude of the associated [K/Fe] enhancement becoming measurable only in stars showing the most extreme effects of O and Mg depletion. Stars enhanced in [K/Fe] have been found so far only in clusters harbouring some Mg-poor stars, while the other globulars, without a Mg-poor sub-population, show small or null [K/Fe] spreads.Comment: 9 pages, 7 figures, 3 tables, accepted for publication in A&

Thermal rearrangements in the tetra-arylcyclopropene series

The literature provides many examples of thermal rearrangements of small-ring compounds to yield systems involving less bond-angle strain. In the arylcyclopropene series these involve, in many cases, fairly complex pathways, and only formalized mechanisms have been suggested

The Elements of the Neutrino Mass Matrix: Allowed Ranges and Implications of Texture Zeros

We study the range of the elements of the neutrino mass matrix m_nu in the charged lepton basis. Neutrino-less double beta decay is sensitive to the ee element of m_nu. We then analyze the phenomenological implications of single texture zeros. In particular, interesting predictions for the effective mass can be obtained, in the sense that typically only little cancellation due to the Majorana phases is expected. Some cases imply constraints on the atmospheric neutrino mixing angle.Comment: 21 pages, 7 figures. Minor corrections, matches version in PR

Reliability analysis of dynamic systems by translating temporal fault trees into Bayesian networks

Classical combinatorial fault trees can be used to assess combinations of failures but are unable to capture sequences of faults, which are important in complex dynamic systems. A number of proposed techniques extend fault tree analysis for dynamic systems. One of such technique, Pandora, introduces temporal gates to capture the sequencing of events and allows qualitative analysis of temporal fault trees. Pandora can be easily integrated in model-based design and analysis techniques. It is, therefore, useful to explore the possible avenues for quantitative analysis of Pandora temporal fault trees, and we identify Bayesian Networks as a possible framework for such analysis. We describe how Pandora fault trees can be translated to Bayesian Networks for dynamic dependability analysis and demonstrate the process on a simplified fuel system model. The conversion facilitates predictive reliability analysis of Pandora fault trees, but also opens the way for post-hoc diagnostic analysis of failures

Spectroscopic binaries among AGB stars from HERMES/Mercator: the case of V Hya

We report on our search for spectroscopic binaries among a sample of AGB stars. Observations were carried out in the framework of the monitoring of radial velocities of (candidate) binary stars performed at the Mercator 1.2m telescope, using the HERMES spectrograph. We found evidence for duplicity in UV Cam, TU Tau, BL Ori, VZ Per, T Dra, and V Hya. This short communication focus on V Hya, found to behave like RV Tau of the b subtype, which are binaries surrounded by a disc.Comment: Poster presented at IAU Symp. 343 "Why Galaxies Care About AGB Stars", Vienna, august 201

An Economic Risk Analysis of Tillage and Cropping Systems on the Arkansas Grand Prairie

No-till (NT) has been shown to reduce fuel, labor, and machinery costs compared to conventional-till (CT) but very few rice producers in Arkansas practice NT. The low adoption rate is most likely due to difficulties in management but also limited information on the profitability and risk of NT. Most rice producers are knowledgeable on NT costs savings but consider it less profitable due to yield reductions offsetting costs savings. This study evaluates production costs, crop yields, and economic risk of both NT and CT in five rice-based cropping systems (continuous rice, rice-soybean, rice-corn, rice-wheat, and rice-wheat-soybean-wheat). Yields, crop prices, and key input prices are simulated to create net return distributions. Stochastic efficiency with respect to a function (SERF) is used to evaluate profitability and risk efficiency. Results indicate that a risk-neutral and risk-averse producer in either NT or CT would prefer a rice-soybean rotation. NT would be preferred over CT in the rice-soybean rotation across all risk preferences. Overall, risk-neutral producers would prefer NT in four of five cropping systems while risk-averse producers would prefer NT in three of five cropping systems.cropping systems, rice, no-till, certainty equivalent, risk premium, Crop Production/Industries, Farm Management, Financial Economics, Land Economics/Use, Production Economics, Risk and Uncertainty,

Assessing the Impacts of Soil Carbon Credits and Risk on No-Till Rice Profitability

Rice is a major cash crop in eastern Arkansas, but most rice acres are intensively cultivated and grown on rented land. No-till is an effective means of sequestering soil carbon and reducing greenhouse gas emissions, and economic incentives exist for no-till in the form of carbon credits. Studies evaluating the economic potential of carbon credits focus on producers only and do not take into consideration the landlord’s perspective. This analysis evaluates the profitability and risk efficiency of no-till management and carbon credits in Arkansas rice production from the prospective if the landlord using simulation and stochastic efficiency with respect to a function (SERF). The results indicate carbon credits may have potential to enhance preference for no-till in rice production by risk-averse landlords.certainty equivalent, landlord, no-till, rice, risk premium, Farm Management, Production Economics, Risk and Uncertainty,