Kinematic study of planetary nebulae in NGC 6822

By measuring precise radial velocities of planetary nebulae (which belong to the intermediate age population), H II regions, and A-type supergiant stars (which are members of the young population) in NGC 6822, we aim to determine if both types of population share the kinematics of the disk of H I found in this galaxy. Spectroscopic data for four planetary nebulae were obtained with the high spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the Magellan telescope at Las Campanas Observatory. Data for other three PNe and one H II region were obtained from the SPM Catalog of Extragalactic Planetary Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m telescope at the Observatorio Astron\'omico Nacional, M\'exico. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 5-6 km s$^{-1}$. Data for three additional H II regions and a couple of A-type supergiant stars were collected from the literature. The heliocentric radial velocities of the different objects were compared to the velocities of the H i disk at the same position. From the analysis of radial velocities it is found that H II regions and A-type supergiants do share the kinematics of the H I disk at the same position, as expected for these young objects. On the contrary, planetary nebula velocities differ significantly from that of the H I at the same position. The kinematics of planetary nebulae is independent from the young population kinematics and it is closer to the behavior shown by carbon stars, which are intermediate-age members of the stellar spheroid existing in this galaxy. Our results are confirming that there are at least two very different kinematical systems in NGC 6822

Fairy circle landscapes under the sea

Short-scale interactions yield large-scale vegetation patterns that, in turn, shape ecosystem function across landscapes. Fairy circles, which are circular patches bare of vegetation within otherwise continuous landscapes, are characteristic features of semiarid grasslands. We report the occurrence of submarine fairy circle seascapes in seagrass meadows and propose a simple model that reproduces the diversity of seascapes observed in these ecosystems as emerging from plant interactions within the meadow. These seascapes include two extreme cases, a continuous meadow and a bare landscape, along with intermediate states that range from the occurrence of persistent but isolated fairy circles, or solitons, to seascapes with multiple fairy circles, banded vegetation, and "leopard skin" patterns consisting of bare seascapes patterns consisting of bare seascapes dotted with plant patches. The model predicts that these intermediate seascapes extending across kilometers emerge as a consequence of local demographic imbalances along with facilitative and competitive interactions among the plants with a characteristic spatial scale of 20 to 30 m, consistent with known drivers of seagrass performance. The model, which can be extended to clonal growth plants in other landscapes showing fairy rings, reveals that the different seascapes observed hold diagnostic power as to the proximity of seagrass meadows to extinction points that can be used to identify ecosystems at risks

Oxidative Stress and Antioxidant Defenses Induced by Physical Exercise

This chapter intends to present the physiological and biochemical mechanisms by which exercise induces the appearance of oxidative stress, as well as the characteristics of the physical exercise that involve the appearance of oxidative stress in the human organism

A compact minimal shadow boundary in Euclidean space is totally geodesic

We prove that a compact minimal shadow boundary of a hypersurface in Euclidean space is totally geodesic. We show that shadow boundaries detect principal directions and umbilical points of a hypersurface. As application we deduce that every shadow boundary of a compact strictly convex surface contains at least two principal direction

Ethics on the corporate websites of the main advertising agencies in Spain

Although a significant number of studies have been carried out in relation to the ethical criteria of advertising messages in Spain, little or no research has been done on the corporate ethics of advertising agencies. Based on a content analysis methodology, the research presented here provides a twofold account of the ethical dimension of agency self-advertising on the Internet by reading (1) corporate ethics statements and (2) corporate identity statements. The results of such reading disclose that only a minimal percentage of companies is bound by particular ethical commitments and only one advertising agency makes explicit reference to ethical concerns in its corporate identity statemen

The incorporation and use of ICT in early childhood education. A study on infrastructure, teachihng methods and teacher training in Andalusia

El objetivo de este artículo es presentar los resultados de un estudio realizado durante el curso 2015-16 sobre la dotación tecnológica con que cuentan las aulas de Educación Infantil en Andalucía, el uso didáctico de los recursos TIC que realizan los docentes, y su formación y actitudes hacia las tecnologías en los procesos de enseñanza y aprendizaje. Aunque existe abundante investigación sobre la etapa de Educación Primaria, Secundaria y en la enseñanza universitaria, resulta palpable la ausencia de estudios en la primera etapa de escolarización en la vida de los niños y niñas. Los datos se recabaron mediante una encuesta en línea respondida por una muestra de 163 maestros/as. Las conclusiones apuntan que la dotación tecnológica de los centros es insuficiente, que tan solo una tercera parte de la muestra de docentes utiliza las TIC de manera cotidiana en el aula, y que el 70% demanda mayor cualificación, y considera que este tipo de recursos son potenciadores de mayor aprendizaje.The aim of this article is to present the results of a recent study on the technological equipment of preschool classrooms in Andalusia, the educational use of ICT resources by teachers and their training and attitudes towards technologies in the process of teaching and learning. Although there is an abundant research on the stage of primary, secondary and university education, it is clear the lack of studies in the first stage of schooling in the lives of children. Data are collected through an online survey answered by a sample of 163 teachers. The conclusions indicate that the provision is insufficient, ICT are used on a daily basis in the classroom only a third of the simple and that 70% of teachers demand higher qualifications and consider that these resources are enhancers higher learning

Integration of solar thermal energy in a conventionaf power plant: The Colon solar project

This paper reports on the first phase of the Colón Solar Project, originally conceived as the hybrid repowering of an existing thermal power plant, with the addition of a gas turbine in a topping configuration integrating thermal energy (steam) produced by a solar system. However, the project developed in a changing economic environment, in which a new legal structure, still incomplete, as of January, 1998 has liberalized the electricity generation market. This forced the original configuration to be modified, resulting in an all-new combined cycle with solar energy integrated into a Heat Recovery Boiler. Basic plant engineering placed special emphasis on the most important solar components (heliostat and receiver), and an economic analysis showed that the plant is profitable under the assumptions of the analysis. Nevertheless, the relatively low IRR, as well as the uncertainty of realization of some of those assumptions, made the utility postpone its decision to build the plant

Ice morphology modification and solute recovery improvement by heating and annealing during block freeze-concentration of coffee extracts

Several treatments on ice blocks can be applied during block freeze-concentration to increase the solute recovery from the ice. In the present study, the changes in the ice block’s temperature and the application of annealing during the block freeze-concentration of aqueous coffee extracts were studied. The ice block was subjected to heating and annealing prior to the thawing stage. The effect of coolant temperature during ice block heating (T = -10 and -5 °C) and the application of annealing (+, -) on solute recovery and ice structure morphology was evaluated. The use of annealing during block freeze-concentration modified the ice crystal morphology and increased the solute recovery only when it is applied at the highest temperature. In general, the annealing process increased the size and circularity of the ice crystals, consequently improving the solute recovery. Thus, annealing can be used to increase the solute recovery during block freeze-concentration.Postprint (published version