Catalytic Asymmetric Reactions of 4‐Substituted Indoles with Nitroethene: A Direct Entry to Ergot Alkaloid Structures

A domino Friedel–Crafts/nitro‐Michael reaction between 4‐substituted indoles and nitroethene is presented. The reaction is catalyzed by BINOL‐derived phosphoric acid catalysts, and delivers the corresponding 3,4‐ring‐fused indoles with very good results in terms of yields and diastereo‐ and enantioselectivities. The tricyclic benzo[cd]indole products bear a nitro group at the right position to serve as precursors of ergot alkaloids, as demonstrated by the formal synthesis of 6,7‐secoagroclavine from one of the adducts. DFT calculations suggest that the outcome of the reaction stems from the preferential evolution of a key nitronic acid intermediate through a nucleophilic addition pathway, rather than to the expected “quenching” through protonation.     

Pre-operational forecasting of sea level height for the Río de la Plata

This paper presents the implementation and calibration of a pre-operational numerical model for the Río de la Plata river. This model is capable of predicting sea level variations in the Río de la Plata, and therefore constitutes a numerical tool of great value for the fluvial–maritime navigation and regional environmental management. A two-dimensional model (MOHID) with nested domains was used to simulate the hydrodynamics. This model was forced with a meso-scale atmospheric model (WRF) and a global tidal model (FES2004). The results obtained include astronomic and meteorological sea level variations in the Río de la Plata. Comparisons of modeled water levels with data have shown very good qualitative and quantitative agreement. The pre-operational test presented in this paper, a 4-day hydrodynamic forecast, was conducted in approximately 18 h.     

Anomalous diffusion governed by a fractional diffusion equation and the electrical response of an electrolytic cell

The electrical response of an electrolytic cell in which the diffusion of mobile ions in the bulk is governed by a fractional diffusion equation of distributed order is analyzed. The boundary conditions at the electrodes limiting the sample are described by an integro-differential equation governing the kinetic at the interface. The analysis is carried out by supposing that the positive and negative ions have the same mobility and that the electric potential profile across the sample satisfies the Poisson's equation. The results cover a rich variety of scenarios, including the ones connected to anomalous diffusion.     

Fibrations of Genus Two on Complex Surfaces

This work is devoted to the study of fibrations of genus 2 by using as its main tool the theory of singular holomorphic foliations. In particular we obtain a sharp differentiable version of Matsumoto–Montesinos theory. In the case of isotrivial fibrations, these methods are powerful enough to provide a detailed global picture of the both the ambient surface and of the structure of the fibrations itself.     

Search for diquark substructures in charmed baryon spectroscopy

We suggest that the present experimental evidence for two Λ_c⁺ mass levels may have a deep physical significance and can be taken as the first hint of (cu) and (cd) diquark substructures within the baryon.     

Characterization of raw and stabilized waste in relation to toxic metals mobility in realistic landfilling scenarios

Toxic metal release in simple leaching tests has been studied in this paper to assess waste behaviour in realistic landfilling scenarios. The waste is a galvanic sludge, raw or cement stabilized. Six different leachants were taken into account: distilled water, CO2-saturated solution, Olsen solution, Mehlich No. 3 solution, acid or alkaline soil circulating solution. Dynamic leaching tests of different duration were used for raw and stabilized waste. The results have shown that, with the exception of Mehlich No. 3 solution, when the waste comes into contact with waters of composition similar to that of the solutions studied, the potential environmental contamination should not be of concern.     

Dynamical model for the ABC effect

We present a model for ABC production, which is experimentally observed in the missing mass spectrum of the reaction $\text{dp}\text{→}{}^3\text{He}\text{+ (}\text{MM}\text{)°}$. The reaction is assumed to be split in two successive steps, namely: (i) N₁p → d_i1 followed by (ii) $\text{N}{}_2\text{d}{}_{\mathrm{<mtext>i</mtext>}}\text{→}{}^3\text{He}\text{π}{}_2\text{,}\text{N}{}_1$ and N₂ being the two nucleons of the incident deuteron and d_i an intermediate deuteron. The total amplitude is factorized into the product of the two amplitudes of reactions (i) and (ii). We know that at low energy these two reactions are dominated by a Δ production. This implies that the total cross sections are given by Breit-Wigner type formulae and that the angular distributions are peaked in the backward and forward directions. The two main results are: (i) at given incident energy, the ABC effect results from the angular distribution of the two intermediate reactions; (ii) the energy dependence of the ABC is deduced from those of the intermediate processes. The resulting fits are generally excellent when the Fermi motion in the initial deuteron is taken into account.     

The structures of lithium inserted metal oxides: Li2FeV3O8

Neutron diffraction powder profile analysis has been used to determine the structure of Li₂FeV₃O₈. The compound is prepared from FeV₃O₈, which has the VO₂(B) structure type, by a lithium insertion reaction employing n-BuLi. Only minimal distortion of the host lattice occurs on Li insertion. The Li ions occupy five coordinate square pyramidal sites with an average LiO bond distance of 2.04 Å. These five coordinate sites occur commonly in the capped perovskite cavities of crystallographic shear structures based on ReO₃.