A VLT study of metal-rich extragalactic H II regions. I. Observations and empirical abundances

We have obtained spectroscopic observations from 3600 Angstrom to 9200 Angstrom with FORS at the Very Large Telescope for approximately 70 H II regions located in the spiral galaxies NGC 1232, NGC 1365, NGC 2903, NGC 2997 and NGC 5236. These data are part of a project aiming at measuring the chemical abundances and characterizing the massive stellar content of metal-rich extragalactic H II regions. In this paper we describe our dataset, and present emission line fluxes for the whole sample. In 32 H II regions we measure at least one of the following auroral lines: [S II]4072, [N II]5755, [S III]6312 and [O II]7325. From these we derive electron temperatures, as well as oxygen, nitrogen and sulphur abundances, using classical empirical methods (both so-called "Te-based methods" and "strong line methods"). Under the assumption that the temperature gradient does not introduce severe biases, we find that the most metal-rich nebulae with detected auroral lines are found at 12+log(O/H)~8.9, i.e. about 60% larger than the adopted solar value. However, classical abundance determinations in metal-rich H II regions may be severely biased and must be tested with realistic photoionization models. The spectroscopic observations presented in this paper will serve as a homogeneous and high-quality database for such purpose.Comment: Accepted for publication in Astronomy and Astrophysic

Life cycle analysis of Jatropha curcas as a sustainable biodiesel feedstock in Argentina

Despite constant changes to the industry in recent years, Argentina remains one of the most important producers of biodiesel in the world. Approximately 90% of the biodiesel produced in Argentina is from soybean, a fact which has raised concern over the fuel´s sustainability. For this reason, alternative crops such as Jatropha curcas are being explored. The aim of this study is to assess the environmental impact of Jatropha-based biodiesel for the specific case of Argentina through life cycle assessment (LCA). The processes considered in this study include Jatropha seed cultivation, seed transportation, oil extraction, and transesterification. Two cultivation scenarios are examined in order to explore trade-offs between land use type and agricultural inputs. This study also incorporates land and water use, which are typically omitted from LCA due to complexity and lack of available information. Inventory data for the system were collected and analyzed using the ReCiPe impact assessment method. The results show a 21% reduction of kg CO2 equivalent for the overall Jatropha biodiesel production process when using fertile land with low-input agriculture instead of marginal land use with fertilizer and irrigation.Fil: Beaver, Alexa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Gonzalez Castaño, Fabio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Díaz, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

Producción de sedimentos y nutrientes en dos cuencas agrícolo-ganaderas del centro de la Provincia de Buenos Aires (Argentina)

Se utilizaron 22 muestras obtenidas entre febrero de 2013 y marzo de 2014 para evaluar la producción de sedimentos y nutrientes en dos cuencas agrícolo-ganaderas del centro de la provincia de Buenos Aires. Se midió la Concentración de Sólidos Suspendidos (CSS) por gravimetría; la fracción gruesa por sedimentación en 48-72hs, y la fracción fina por filtración del sobrenadante por fibra de vidrio (capacidad de retención: 0,5μm). Las muestras del arroyo Videla (135km2) fueron tomadas con caudales entre 0,27 y 1,10m3/s. La CSS media fue de 28g/m3, y el caudal sólido medio fue de 1280kg/día, siendo el 95% material grueso. La producción media de fósforo y nitrógeno fue de 4,43 y 239kg/día respectivamente, el 88% en forma de nitrato. Las muestras del arroyo Santa Catalina (121km2) fueron tomadas con caudales entre 0,09 y 0,61m3/s. La CSS media fue de 93g/m3, y el caudal sólido medio fue de 2118kg/día, siendo el 90% material grueso. La producción media de fósforo y nitrógeno fueron de 7,09 y 78kg/día respectivamente, el 69% en forma de nitrato. Se observaron diferencias significativas en la CSS, y la concentración de fósforo y nitrógeno entre ambas cuencas (α>0,95; test de Wilcoxon).Twenty two samples collected between February 2013 and March 2014 were used to evaluate the production of sediments and nutrients of two basins located in the center of Buenos Aires province. Total Suspended Solids (TSS) was measured by gravimetry; the coarse fraction by sedimentation on 48-72 hours, and the fine fraction by filtering the supernatant through glass fiber filter (0,5μm retention capacity). Samples from Videla stream (135km2) were collected during 0,27 to 1,10m3/s water flowrate. Average TSS was 28g/m3, and the average solid load was 1280kg/day, 95% coarser material. Average production of phosphorus and nitrogen were 4,43 and 239kg/day respectively, 88% as nitrate. Samples from Santa Catalina stream (121km2) were collected during 0,09 to 0,61m3/s water flowrate. Average TSS was 93g/m3, and the average solid load was 2118kg/day, 90% as coarser material. Average production of phosphorus and nitrogen were 7,09 and 78kg/day respectively, 69% as nitrate. Significant differences in TSS, nitrogen and phosphorus concentration were observed between these two basins (α>0,95; Wilcoxon test)

The path to next generation biofuels: successes and challenges in the era of synthetic biology

Volatility of oil prices along with major concerns about climate change, oil supply security and depleting reserves have sparked renewed interest in the production of fuels from renewable resources. Recent advances in synthetic biology provide new tools for metabolic engineers to direct their strategies and construct optimal biocatalysts for the sustainable production of biofuels. Metabolic engineering and synthetic biology efforts entailing the engineering of native and de novo pathways for conversion of biomass constituents to short-chain alcohols and advanced biofuels are herewith reviewed. In the foreseeable future, formal integration of functional genomics and systems biology with synthetic biology and metabolic engineering will undoubtedly support the discovery, characterization, and engineering of new metabolic routes and more efficient microbial systems for the production of biofuels

Modern GPR Target Recognition Methods

Traditional GPR target recognition methods include pre-processing the data by removal of noisy signatures, dewowing (high-pass filtering to remove low-frequency noise), filtering, deconvolution, migration (correction of the effect of survey geometry), and can rely on the simulation of GPR responses. The techniques usually suffer from the loss of information, inability to adapt from prior results, and inefficient performance in the presence of strong clutter and noise. To address these challenges, several advanced processing methods have been developed over the past decade to enhance GPR target recognition. In this chapter, we provide an overview of these modern GPR processing techniques. In particular, we focus on the following methods: adaptive receive processing of range profiles depending on the target environment; adoption of learning-based methods so that the radar utilizes the results from prior measurements; application of methods that exploit the fact that the target scene is sparse in some domain or dictionary; application of advanced classification techniques; and convolutional coding which provides succinct and representatives features of the targets. We describe each of these techniques or their combinations through a representative application of landmine detection.Comment: Book chapter, 56 pages, 17 figures, 12 tables. arXiv admin note: substantial text overlap with arXiv:1806.0459

Distance Education: Effects of individual factors on the perceived image of high education institutions

Current changes in the socioeconomic variables in which both public and private universities interact require them to manage their image to attract and satisfy their students. Added to this, new technologies are affecting education, increasing the supply and relevance of distance learning in the university structure. Given that, this research aimed to understand which individual factors cause significant differences in perceived university image. This study is a descriptive field research. We collected the data with a survey and analysed the results using factor analyses, t-tests, and linear regression. We found that gender, age, income, and length of interaction between the students and the organization do not influence the overall image. However, the exact sciences students presented a different perception of the researched institutions. Given the results, we concluded that perceived image can be seen as a momentary picture. The study indicates the image as a multidimensional construct. This construct is most expressively associated with intangible aspects