Model Atmospheres for Irradiated Giant Stars: Implications for the Galactic Center

Irradiation of a stellar atmosphere by an external source (e.g. an AGN) changes its structure and therefore its spectrum. Using a state-of-the-art stellar atmosphere code, we calculate the infrared spectra of such irradiated and transformed stars. We show that the original spectrum of the star, which is dominated by molecular bands, changes dramatically when irradiated even by a low-luminosity AGN ($L_{\rm X} = 10^{33}$ erg s$^{-1}$), becoming dominated by atomic lines in absorption. We study the changes in the spectrum of low-mass carbon- and oxygen-rich giant stars as they are irradiated by a modest AGN, similar to the one at the Galactic center (GC). The resulting spectra are similar to those of the faintest S-cluster stars observed in the GC. The spectrum of a star irradiated by a much brighter AGN, like that powered by a tidally disrupted star, is very different from that of any star currently observed near the GC. For the first time we have discovered that the structure of the atmosphere of an irradiated giant changes dramatically and induces a double inversion layer. We show that irradiation at the current level can explain the observed trend of CO band intensities decreasing as a function of increasing proximity to Sg $A^{*}$. This may indicate that (contrary to previous claims) there is no paucity of old giants in the GC, which coexist simultaneously with young massive stars.Comment: Submitted to ApJ; typo in name correcte

Mother's or teacher's education? Educational stratification and grade progression in Brazil.

grade progression; education; hierarchical linear model; educational achievement; Brazil

Why Environmental Policies Fail

Proposing environmental policy which is consistent with the laws of nature, this book is for those who are not just interested in the ways humans have harmfully altered their environment, but instead wish to learn why the many governmental policies in place to curb such behaviour have been unsuccessful. Since humans began to exploit natural resources for their own economic ends, we have ignored a central principle - nature and humans are not separate but are a unified interconnected system, where neither is superior to the other. Policy must reflect this reality. We failed to follow this principle in exploiting natural capital without expecting to pay any price and in hurriedly adopting environmental laws and policies that reflected how we wanted nature to work, instead of how it does work. This study relies on more accurate models for how nature works and humans behave

THE RATE OF RETURN ON EXPENDITURES OF THE SOUTH AFRICAN AGRICULTURAL RESEARCH COUNCIL (ARC)

All the rate of return estimates, regardless of methodology or the level of aggregation, are entirely consistent and logical. The returns show that the ARC has been extremely successful economically and has followed a sound strategy of exploiting spillovers from foreign R&D systems. However, there must be a strong socio-economic component to the ARC's efforts if it is to reach the disadvantaged.Research and Development/Tech Change/Emerging Technologies,

Congruence, non-homology, and the phylogeny of basal turtles

Modern cladistic analysis is characterized by the assembly of increasingly larger data sets coupled with the use of congruence as the final test of homology. Some critics of this development have recently called for a return to more detailed primary homology analysis while questioning the utility of congruence. This discussion appears to be central to the debate regarding the phylogenetic relationships of basal turtles, as the large data sets developed by us have been criticized recently for utilizing poorly constructed characters and including too many homoplasy-prone characters. Our analysis of this critique reveals that (1) new information regarding poorly understood taxa has a greater impact on the outcome of turtle phylogenies than the characters under dispute; (2) most current turtle phylogenies differ in taxon sampling, not character sampling, and so it appears illogical to condemn a particular analysis for its character sampling; (3) even evolutionary taxonomists should agree that key characters utilized to resolve basal turtle relationships cannot be thought to be 'infallible'; (4) whereas various criteria provide positive evidence for homology, only congruence provides positive evidence for non-homology; and (5) a stalemate between conflicting camps within a congruence frame work is preferable to the ad hoc dismissal of data sets, because authoritative statements are untestable.Fil: Joyce, W. G.. University of Yale; Estados UnidosFil: Sterli, Juliana. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Industrialización de la riqueza vegetal: oportunidades sociales y económicas

Las empresas enfrentan un importante desafío es esta economía globalizada, porque para sobrevivir tienen que ofrecer nuevos productos con valor agregado en los mercados internacionales. Para ello se requieren profesionales entrenados en las metodologías para el desarrollo de nuevos productos (DNP), y los egresados universitarios tienen que tener estas habilidades para que puedan contribuir a enfrentar esta situación. J unto con esto se requieren también productos innovadores de la mano con la conservación del medio ambiente y aprovechando al máximo los recursos disponibles, bien sea de la tierra o de transformación tecnológica. Con este proyecto se pretende abrir una ventana de oportunidad para que los alumnos del programa de Ingeniería de Procesos puedan adquirir el entrenamiento necesario para desempeñarse con éxito en el DNP. A demás, los empresarios del campo puedan obtener un valor agregado para sus productos como alternativa en tiempos de precios desfavorables.Companies face a major challenge is this globalized economy, because to survive they have to offer new products with added value in the international market. This requires professionals trained in the methodologies for the development of new products (DNP) and university graduates must have these skills so that they can contribute to deal with this situation. A long with this they also require innovations running by the side of conservation of the environment and the taking of full advantage of available resources, either from land or technological transformation. This project is to open a window of opportunity so that the Process Engineering students can acquire the knowledge needed to perform successfully in the DNP training. A lso field employers can get valueadded products as an alternative in times of unfavourable prices

Global analysis of mannitol 2-dehydrogenase in lactobacillus reuteri crl 1101 during mannitol production through enzymatic, genetic and proteomic approaches

Several plants, fungi, algae, and certain bacteria produce mannitol, a polyol derived from fructose. Mannitol has multiple industrial applications in the food, pharmaceutical, and medical industries, being mainly used as a non-metabolizable sweetener in foods. Many heterofermentative lactic acid bacteria synthesize mannitol when an alternative electron acceptor such as fructose is present in the medium. In previous work, we reported the ability of Lactobacillus reuteri CRL 1101 to efficiently produce mannitol from sugarcane molasses as carbon source at constant pH of 5.0; the activity of the enzyme mannitol 2-dehydrogenase (MDH) responsible for the fructose conversion into mannitol being highest during the log cell growth phase. Here, a detailed assessment of the MDH activity and relative expression of the mdh gene during the growth of L. reuteri CRL 1101 in the presence of fructose is presented. It was observed that MDH was markedly induced by the presence of fructose. A direct correlation between the maximum MDH enzyme activity and a high level of mdh transcript expression during the log-phase of cells grown in a fructose-containing chemically defined medium was detected. Furthermore, two proteomic approaches (2DE and shotgun proteomics) applied in this study confirmed the inducible expression of MDH in L. reuteri. A global study of the effect of fructose on activity, mdh gene, and protein expressions of MDH in L. reuteri is thus for the first time presented. This work represents a deep insight into the polyol formation by a Lactobacillus strain with biotechnological potential in the nutraceutics and pharmaceutical areas.Fil: Ortiz, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Fadda, Silvina G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Picariello, Gianluca. Istituto Di Scienze Dell'alimentazione; ItaliaFil: Hebert, Elvira Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Raya, Raul Ricardo. University of Toronto; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Tardigrades from Fayette County, Georgia

Only three species from the phylum Tardigrada have been reported in Georgia. Samples of leaf litter and cryptogams collected in 2003 in Fayette County, Georgia, were examined for the presence of tardigrades. Diphascon (Diphascon) pinque, Macrobiotus coronatus, Macrobiotus harmsworthii, Macrobiotus hibiscus, Macrobiotus richtersi, Minibiotus furcatus, Minibiotus intermedius, Isohypsibius nodosus, and Milnesium tardigradum were present in the samples. All nine are additions to the fauna of Georgia