Radiative capture reaction for 17^{17}Ne formation within a full three-body model

Background: The breakout from the hot Carbon-Nitrogen-Oxigen (CNO) cycles can trigger the rp-process in type I x-ray bursts. In this environment, a competition between $^{15}\text{O}(\alpha,\gamma){^{19}\text{Ne}}$ and the two-proton capture reaction $^{15}\text{O}(2p,\gamma){^{17}\text{Ne}}$ is expected. Purpose: Determine the three-body radiative capture reaction rate for ${^{17}\text{Ne}}$ formation including sequential and direct, resonant and non-resonant contributions on an equal footing. Method: Two different discretization methods have been applied to generate $^{17}$Ne states in a full three-body model: the analytical transformed harmonic oscillator method and the hyperspherical adiabatic expansion method. The binary $p$--$^{15}$O interaction has been adjusted to reproduce the known spectrum of the unbound $^{16}$F nucleus. The dominant $E1$ contributions to the $^{15}\text{O}(2p,\gamma){^{17}\text{Ne}}$ reaction rate have been calculated from the inverse photodissociation process. Results: Three-body calculations provide a reliable description of $^{17}$Ne states. The agreement with the available experimental data on $^{17}$Ne is discussed. It is shown that the $^{15}\text{O}(2p,\gamma){^{17}\text{Ne}}$ reaction rates computed within the two methods agree in a broad range of temperatures. The present calculations are compared with a previous theoretical estimation of the reaction rate. Conclusions: It is found that the full three-body model provides a reaction rate several orders of magnitude larger than the only previous estimation. The implications for the rp-process in type I x-ray bursts should be investigated.Comment: 10 pages, 10 figures. Corrected versio

The continuum description with pseudo-state wave functions

Benchmark calculations are performed aiming to test the use of two different pseudo-state bases on the the Multiple Scattering expansion of the total Transition amplitude (MST) scattering framework. Calculated differential cross sections for p-6He inelastic scattering at 717 MeV/u show a good agreement between the observables calculated in the two bases. This result gives extra confidence on the pseudo-state representation of continuum states to describe inelastic/breakup scattering.Comment: 4 pages, 2 figures. Published in Physical Review

The boundary field theory induced by the Chern-Simons theory

The Chern-Simons theory defined on a 3-dimensional manifold with boundary is written as a two-dimensional field theory defined only on the boundary of the three-manifold. The resulting theory is, essentially, the pullback to the boundary of a symplectic structure defined on the space of auxiliary fields in terms of which the connection one-form of the Chern-Simons theory is expressed when solving the condition of vanishing curvature. The counting of the physical degrees of freedom living in the boundary associated to the model is performed using Dirac's canonical analysis for the particular case of the gauge group SU(2). The result is that the specific model has one physical local degree of freedom. Moreover, the role of the boundary conditions on the original Chern- Simons theory is displayed and clarified in an example, which shows how the gauge content as well as the structure of the constraints of the induced boundary theory is affected.Comment: 10 page

Screening of heterogeneous surfaces: charge renormalization of Janus particles

Nonlinear ionic screening theory for heterogeneously charged spheres is developed in terms of a mode-decomposition of the surface charge. A far-field analysis of the resulting electrostatic potential leads to a natural generalization of charge renormalization from purely monopolar to dipolar, quadropolar, etc., including mode-couplings. Our novel scheme is generally applicable to large classes of surface heterogeneities, and is explicitly applied here to Janus spheres with differently charged upper and lower hemispheres, revealing strong renormalization effects for all multipoles.Comment: 2 figure

Influence of Rhizobium and Mycorrhizae in the Production of Seedlings of Caesalpinia Spinosa L. Taya in San Pablo, Peru

This research study evaluated the symbiotic influence of Mycorrhizae in the production of propagating material of Caesalpinia Spinosa L. Taya, as well as the characterization of strains of mycorrhitic fungi in field, nursery, and laboratory work. No nodules were found as a product of nitrifying bacteria in the roots of plants Caesalpinea spinosa L., and ectomycorrhitic fungi were identified in the rhizosphere, such as Basidiomicetes and species of Rhizoctonia sp and Fusarium sp. From the evaluations, T4 exceeded all treatments, such as in height, neck diameter, number of leaves, root length, and the wet and dry weight of Taya seedling. In conclusion, we say that the Caesalpinia Spinosa L. Taya, despite of belonging to the legume family, does not present nodulation; but the presence of ectomycorrhitic fungi such as the basidiomicetes in the rhizosphere and high content of organic matter, positively influences the increase in the volume of seedling in the nursery, also reflected in the absorption of protein and phosphorus. Keywords: mycorrhizal association, seedlings, rhizobium. Resumen En el presente trabajo de investigación se evaluó la influencia simbiótica de micorrizas en la producción de plantones de Caesalpinea spinosa L. Taya, así como la caracterización de cepas de hongos micorríticos, realizándose el trabajo en campo, vivero, y laboratorio. No se encontró nódulos como producto de bacterias nitrificantes en las raíces de las plantas de Caesalpinea spinosa L., y se identificó hongos ectomicorríticos en la rizósfera, tales como Basidiomicetes y especies de Rhizoctonia sp y Fusarium sp. De las evaluaciones el T4, supera a todos los tratamientos como en altura, diámetro de cuello, número de hojas, longitud de raíz, peso húmedo y peso seco de plántula.Concluyendo finalmente, diremos que la Caesalpinea spinosa L. taya, a pesar de pertenecer a la familia de las Leguminosas no presenta nodulación; pero la presencia de los hongos ectomicorríticos como los basidiomicetes en la rizósfera y el alto contenido de materia orgánica, influye positivamente en el incremento del volumen de la plántula en vivero, reflejado también en la absorción de proteínas y fosforo. Palabras clave: asociación micorrítica, plantones, rizobium

Anaerobic granular sludge as a biocatalyst for 1,3-propanediol production from glycerol in continuous bioreactors

1,3-propanediol (1,3-PDO) was produced from glycerol in three parallel Expanded Granular Sludge Blanket (EGSB) reactors inoculated with granular sludge (control reactor-R1), heat-treated granular sludge (R2) and disrupted granular sludge (R3) at Hydraulic Retention Times (HRT) between 3 and 24 h. Maximum 1,3-PDO yield (0.52 mol mol-1) and productivity (57 g L-1 d-1) were achieved in R1 at HRTs of 12 h and 3 h, respectively. DGGE profiling of PCR-amplified 16S rRNA gene fragments showed that variations in the HRT had a critical impact in the dominant community of microorganisms. However, no appreciable differences in the bacterial population were observed between R2 and R3 at low HRTs. Production of H2 was observed at the beginning of the operation, but no methane production was observed. This study proves the feasibility of 1,3-PDO production in EGSB reactors and represents a novel strategy to valorise glycerol generated in the biodiesel industry

Decision support systems and models for aiding irrigation and nutrient management of vegetable crops

Vegetable growers in Europe are continually under increasing pressure to optimize irrigation and nutrient management. This results from the widespread effects of climate change and of competition from other sectors for water, and increasing societal pressure to reduce nutrient contamination of water bodies. The widespread and growing adoption of drip irrigation and fertigation provides vegetable growers with the technical infrastructure for greatly improved irrigation and nutrient management. However, quantitative decisions to achieve optimal irrigation and nutrient management, and increasingly of the two together, require complex decision-making. Numerous factors regarding climate, soil characteristics, field infrastructure, and crop characteristics need to be considered. Decision Support Systems (DSSs) and simulation models are tools that process large and diverse amounts of information to provide irrigation and nutrient recommendations that are specific to individual crops and sites. Commonly, DSSs incorporate simulation models, which enables site and crop specific assessment, and the possibility for dynamic responses to fluctuations in climate etc. There is an on-going trend for web-based DSSs that can access on-line data bases such as of climate and soil data, and that users consult with smartphone Apps. This article firstly reviews several general aspects regarding the use of DSSs/models in commercial vegetable production, such as how to enhance their user-friendliness. Subsequently, it describes DSSs/models that have been developed or are being used to assist with irrigation or nutrient management, or both, of vegetable crops. The most relevant aspects of these DSSs/models are highlighted. In addition to DSSs/models for practical on-farm management, the use of DSSs/models for scenario analysis to demonstrate theoretical case studies to policy makers, growers and advisors is discussed. A focus throughout is on how to make these products attractive and effective to potential users. The geographical focus is on Europe; however, particularly relevant cases from elsewhere are also considered. With the current state of Information and Communication Technology (ICT), and considering the inevitable future developments, DSSs can provide vegetable growers with effective and user-friendly tools to assist them to optimize irrigation and nutrient management