Born-Infeld Cosmologies

We present a model for an inhomogeneous and anisotropic early universe filled with a nonlinear electromagnetic field of Born-Infeld (BI) type. The effects of the BI field are compared with the linear case (Maxwell). Since the curvature invaria nts are well behaved then we conjecture that our model does not present an initial big bang singularity. The existence of the BI field modifies the curvature invariants at t=0 as well as sets bounds on the amplitude of the conformal metric functionComment: 13 pages, latex, 6 eps figure

Combining interactive GIS tools and expert knowledge in validation of tree species models

Poster presented at XIII Congreso Forestal Mundial. FAO, Buenos Aires (Argentina). 18-25 Oct 200

Effect of Genotype and Environment on the Glycoalkaloid Content of Rare, Heritage, and Commercial Potato Varieties

peer-reviewedPotatoes accumulate toxic steroidal compounds that could be harmful for humans if consumed in high quantities and must be controlled. In this study, we were interested in assessing the levels and variation of glycoalkaloid content in 60 varieties of potato planted in 2 trial sites over 2 y. Total glycoalkaloid levels ranged from 4 to 957 mg/kg of dry weight in the flesh and from 150 to 8133 mg/kg in the skin, with the latter accumulating generally more α-chaconine than α-solanine. Contents in the flesh were below the safe limit for all varieties, but were generally above in the skin. Maximum values in each site and year of cultivation were found for varieties “Beauty of Hebron,” “May Queen,” and “Arran Pilot” in the skin and “Beauty of Hebron,” “International Kidney,” and “Congo” in the flesh. Year of cultivation had a significant effect on total glycoalkaloid content (P < 0.0001), with interactions between variety and site of cultivation and variety and year of cultivation also significant (P < 0.0001), implying that environmental effects seem to act differentially and could induce high levels in genetically predisposed varieties.Teagasc Walsh Fellowship Programm

Hamster leukemia virus: lack of endogenous DNA synthesis and unique structure of its DNA polymerase

Infectious hamster leukemia virus (HaLV) contains a DNA polymerase different from those of murine and avian viruses. No endogenous reaction directed by the 60 to 70S RNA of HaLV could be demonstrated in detergenttreated HaLV virions, nor could the purified DNA polymerase copy added viral RNA. The virion RNA could, however, act as template for added avian myeloblastosis virus DNA polymerase and the HaLV DNA polymerase could efficiently utilize homopolymers as templates. The HaLV enzyme was like other reverse transcriptases in that certain ribohomopolymers were much better templates than the homologous deoxyribohomopolymers. No ribonuclease H activity could be shown in the HaLV enzyme, but neither could activity be found in the murine leukemia virus DNA polymerase. The hamster enzyme was unique in that poly(A) ·oligo(dT) was a poor template, and globin mRNA primed with oligo(dT) was totally inactive as a template. Its uniqueness was also indicated by its subunit composition; electrophoresis of the HaLV DNA polymerase in sodium dodecyl sulfate-containing polyacrylamide gels revealed equimolar amounts of two polypeptides of molecular weight 68,000 and 53,000. The sedimentation rate of the enzyme in glycerol gradients was consistent with a structure containing one each of the two polypeptides. The enzyme thus appears to be structurally distinct from other known virion DNA polymerases. Its inability to carry out an endogenous reaction in vitro might result from an inability to utilize certain primers

The Rise and Fall of Income Inequality in Mexico: 1989-2010

Inequality in Mexico rose between 1989 and 1994 and declined between 1994 and 2010. We examine the role of market forces (demand and supply of labour by skill), institutional factors (minimum wages and unionization rate), and public policy (cash transfers) in explaining changes in inequality. We apply the ‘re-centered influence function’ method to decompose changes in hourly wages into characteristics and returns. The main driver is changes in returns. Returns rose (1989-1994) due to institutional factors and labor demand. Returns declined (1994-2006) due to changes in supply and --to a lesser extent--in demand; institutional factors were not relevant. Government transfers contributed to the decline in inequality, especially after 2000.inequality, wages, disposable income, labor markets, Mexico

Comparison of phenolic and flavonoid content and antioxidant activity in vitro among potato varieties.

Conference paperDiets rich in fruits and vegetables have been associated with a lower incidence of cancer and heart disease, which may be related to the antioxidant activity of bioactive compounds present in these foods. Phenolic compounds are potent antioxidants in vitro, of which flavonoids are of particular interest for their potential positive impact on health. Potatoes are one of the most consumed vegetables in the world and therefore an important source of phenolics. In Ireland they are the third most important crop with a farm gate value of approximately 45 million euros annually. The aim of this work was to evaluate the antioxidant activity of methanolic solutions extracted from the skin and flesh of potato tubers against the stable radical DPPH and analyze its relationship to the content of total phenolics and total flavonoids.Teagasc Walsh Fellowship Programm

Use of family history information in school-based prevention practice

Includes bibliographical references.Research studies have demonstrated the impact of a positive family history in children, and the likelihood that they may develop specific language impairment (SLI). SLI is a high incidence condition, estimated to affect 7% of the kindergarten population (Tomblin, Records, Buckwalter, Zhang, Smith, & O'Brien, 1997). SLI is characterized by pronounced difficulty with language development in the absence of frank neurological, cognitive, social, or hearing impairments (Leonard, 1998). Children identified as having SLI display asynchronous language development with pronounced difficulties in the development of morphosyntax. It is important to note that specific language impairment differs from a language delay. A child that demonstrates a language delay would demonstrate language skills that are slow to emerge, but language skills develop in the same sequence seen in typically developing children. Implications of a language delay suggest that a child will overcome the delay and catch up (Reed, 1994). Noting this distinction, it is important to recognize that children identified as language disordered will not simply catch up to their peers. A review of the literature on children at risk for developmental language and/or reading disabilities reveals the importance of early screening and identification for maximizing language and academic outcomes. Thus, best practice would indicate the need to implement early screening and identification of children with or at-risk for language and/or reading disabilities to achieve optimal developmental outcomes.B.S. (Bachelor of Science

La proyección del infierno medieval en Hispanoamérica

El proceso de evangelización y adoctrinamiento de la población americana se valió, entre otros medios, de la imagen pictórica para implementar los dogmas y creencias de la Iglesia católica. La representación de las penas y tormentos infernales en vastos programas iconográficos en capillas de indios, desde el siglo XVI al XIX, testimonian una intencionalidad didáctica, persuasiva y coercitiva para lograr la conversión de la población indígena. El análisis iconográfico de algunos conjuntos pictóricos de Mesoamérica y el centro y sur andinos pretende demostrar la pervivencia de motivos y esquemas compositivos del arte infernal medieval