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

Microbial Community Composition during a Bloom of Purple Bacteria in Intertidal Sediments in Vigo (Northwest Spain)

In summer 2019, a large, bright pink microbial mat was visible on top of macroalgal deposits in muddy sediments of an urban beach (Playa do Adro, Vigo). In order to characterize the dominant organisms in these colored mats, results from microscopic observations, photosynthetic pigments, and molecular analysis were gathered. Light microscopy examination revealed pinkish microbial aggregates with minor contributions of larger protists and cyanobacteria. High-performance liquid chromatography (HPLC) pigment analysis documented the dominance of bacteriochlorophyll a and carotenoids whose spectra were compatible with those described in photosynthetic purple bacteria. 16S rRNA gene amplicon sequencing confirmed that the vast majority of reads belonged to Proteobacteria (73.5%), and among them, nearly 88% of those reads belonged to purple sulfur bacteria (Gammaproteobacteria). A single family, Chromatiaceae, constituted the bulk of this assemblage, including the genera Thiohalocapsa (32%), Marichromatium (12.5%), Phaeochromatium (5%), and Halocromatium (2%) as main contributors. Nonetheless, a considerable number of sequences could not be assigned to a particular genus, stressing the large biological diversity in these microbial mats and the potential presence of novel taxa of purple sulfur bacteria.En prens

Análisis nutricional: el consumo de calorías de la población pobre en Argentina

Existe una creencia generalizada entre los economistas que la inseguridad alimentaria y el hambre son el resultado de la pobreza. Muchos sostienen que el crecimiento económico y los aumentos en los niveles de ingreso de los hogares pobres mejorarán la habilidad y el deseo de los mismos por adquirir una dieta adecuada, al menos en términos de la energía aportada por los alimentos (calorías). Teniendo en cuenta la dispar distribución de los gastos en alimentos debido a la creciente desigualdad en los niveles de vida de nuestro país, el objetivo del presente trabajo es analizar las deficiencias de nuestra población en la satisfacción de los requerimientos mínimos nutricionales, evaluar el aporte calórico de los distintos grupos de alimentos y cuantificar el grado de sensibilidad de las calorías a las variaciones en el ingreso. Además se realiza un análisis exploratorio para identificar las características de los hogares con deficiencias calóricas. La generación de información para nuestro país sobre estos aspectos es el paso previo para evaluar la eficacia de programas dirigidos a disminuir los niveles de pobreza y desnutrición otorgando subsidios directos en dinero o raciones de alimentos. Además de orientar las decisiones para la producción de alimentos estratégicos en la mejora de los niveles nutricionales de los hogares más carenciados o vulnerables.Fil: Rodríguez, Elsa Mirta M. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Garrido, Laura. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Gentile, Natacha. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Lupín, Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina

Implications of plant material origin, land use history and soil properties in the incidence of verticillium wilt in olive groves

8 páginas, 2 figuras, 1 tabla.The increased presence of Verticillium wilt (Verticillium dahliae Kleb.) in olive groves is often related to the use of infected propagation material and to the planting of new olive trees in contaminated soils. This study assessed the implications of plant propagation, land-use history and soil properties on disease prevalence in southern Spain, the most important olive-growing area worldwide. To this purpose, a large-scale sampling survey was carried out in this area, V. dahliae pathotypes were identified by PCR, and GIS was used to analyze soil properties and cropland-use history. Finally, multiple correspondence analysis was performed to show the statistical association between the variables taken into account. Results strongly indicated the potential risk of planting olive in valleys with irrigated cropland history, especially those that had hosted herbaceous crops, highlighted the importance of using pathogen-free certified planting material as a key component for a successful disease management, and confirmed the role played by saline, alkaline, and steep-slope soils in enhancing V. dahliae prevalence.The research was supported by Caja Rural Foundation.Peer reviewe

Three-body structure of low-lying 18Ne states

We investigate to what extent 18Ne can be descibed as a three-body system made of an inert 16O-core and two protons. We compare to experimental data and occasionally to shell model results. We obtain three-body wave functions with the hyperspherical adiabatic expansion method. We study the spectrum of 18Ne, the structure of the different states and the predominant transition strengths. Two 0+, two 2+, and one 4+ bound states are found where they are all known experimentally. Also one 3+ close to threshold is found and several negative parity states, 1-, 3-, 0-, 2-, most of them bound with respect to the 16O excited 3- state. The structures are extracted as partial wave components, as spatial sizes of matter and charge, and as probability distributions. Electromagnetic decay rates are calculated for these states. The dominating decay mode for the bound states is E2 and occasionally also M1.Comment: 17 pages, 5 figures (version to appear in EPJA

Una transdisciplina de estudios del discurso.

El análisis del discurso es un vasto dominio en el que convergen múltiples disciplinas y variados enfoques. Todos ellos han de compenetrarse si se quiere dar cabida a la multiplicidad de fenómenos discursivos de los que se viene hablando desde hace ya medio siglo. Lo que pretendemos en este trabajo es desarrollar la idea planteada por T. A. Van Dijk en su artículo "The study of discourse" (1997), en el que defiende la necesidad de crear UIUI. Transdiscisplina de estudios del discurso. Dicha macrodisciplina incluye todas las que hasta ahora han sido consideradas disciplinas involucradas en el análisis discursivo. De este modo se puede dar cuenta y explicar de forma más coherente cada una de las dimensiones discursivas a las que Van Dijk hace referencia en el mencionado artículo y que aquí vamos a presentar

An instrumental puzzle: the modular integration of AOLI

The Adaptive Optics Lucky Imager, AOLI, is an instrument developed to deliver the highest spatial resolution ever obtained in the visible, 20 mas, from ground-based telescopes. In AOLI a new philosophy of instrumental prototyping has been applied, based on the modularization of the subsystems. This modular concept offers maximum flexibility regarding the instrument, telescope or the addition of future developments.Comment: 10 pages, 8 figures, Proc. SPIE 9908, Ground-based and Airborne Instrumentation for Astronomy VI, 99082Z (August 9, 2016

Performance and challenges in the value chain of the Anadara tuberculosa bivalve mollusk in Ecuador

The bivalve mollusk, Anadara tuberculosa (Black Shell, in Spanish Concha Prieta), is found on America’s Pacific coast, where it is harvested for subsistence and commercial markets. This paper aims to diagnose the performance of the black shell’s value chain. We also identify several challenges that must be addressed to improve the sustainability of the black shell fishery in Ecuador. The applied methodology was quantitative and descriptive. Its design was non-experimental, field, cross-sectional and ex post facto. The investigation was carried out from January to October 2019 in the Jambelí archipelago, El Oro province, Ecuador. The study population consisted of 565 individuals, shellfish collectors, shellfish associations managers, traders, and restaurants from the A. tuberculosa production chain. The sample size was estimated at 222 informants. The type of sampling used was probabilistic, random, stratified, and with proportional allocation, with an effective participation rate of those selected of approximately 80%. The questionnaire was applied personally through the structured survey method, in writing, in the work area, and with their consent. The performance of the value chain was diagnosed in the dimensions of productivity, competitiveness, and quality of life, reaching a 75.1% index, a result that indicates that the value chain has a moderate to good performance level. The competitiveness dimension reached the highest performance, followed by productivity. Quality of life was the dimension with the lowest performance. The value chain can be improved if the following challenges are met: (1) Restoration of the mangrove ecosystem, (2) Promotion of low-intensity shellfish aquaculture, (3) Good sanitary management and purification, (4) Promotion of value-focused ventures, (5) Strengthening of organizations and agreements for the use and custody of mangroves, and (6) Strengthening of institutions that contribute to the advancement of these challenge

A photometric monitoring of bright high-amplitude delta Scuti stars. II. Period updates for seven stars

We present new photometric data for seven high-amplitude delta Scuti stars. The observations were acquired between 1996 and 2002, mostly in the Johnson photometric system. For one star (GW UMa), our observations are the first since the discovery of its pulsational nature from the Hipparcos data.The primary goal of this project was to update our knowledge on the period variations of the target stars. For this, we have collected all available photometric observations from the literature and constructed decades-long O-C diagrams of the stars. This traditional method is useful because of the single-periodic nature of the light variations. Text-book examples of slow period evolution (XX Cyg, DY Her, DY Peg) and cyclic period changes due to light-time effect (LITE) in a binary system (SZ Lyn) are updated with the new observations. For YZ Boo, we find a period decrease instead of increase. The previously suggested LITE-solution of BE Lyn (Kiss & Szatmary 1995) is not supported with the new O-C diagram. Instead of that, we suspect the presence of transient light curve shape variations mimicking small period changes.Comment: 11 pages, 15 figures, accepted for publication in A&