986 research outputs found

    Lelong numbers on projective varieties

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    Given a positive closed (1,1)-current TT defined on the regular locus of a projective variety XX with bounded mass near the singular part of XX and YY an irreducible algebraic subset of XX, we present uniform estimates for the locus inside YY where the Lelong numbers of TT are larger than the generic Lelong number of TT along YY

    Continuum and Spectral Line Radiation from a Random Clumpy Medium

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    We present a formalism for continuum and line emission from random clumpy media together with its application to problems of current interest, including CO spectral lines from ensembles of clouds and radio emission from HII regions, supernovae and star-forming regions. For line emission we find that the effects of clump opacity on observed line ratios can be indistinguishable from variations of intrinsic line strengths, adding to the difficulties in determining abundances from line observations. Our formalism is applicable to arbitrary distributions of cloud properties, provided the cloud volume filling factor is small; numerical simulations show it to hold up to filling factors of about 10%. We show that irrespective of the complexity of the cloud ensemble, the radiative effect of clumpiness can be parametrized at each frequency by a single multiplicative correction to the overall optical depth; this multiplier is derived from appropriate averaging over individual cloud properties. Our main finding is that cloud shapes have only a negligible effect on radiation propagation in clumpy media; the results of calculations employing point-like clouds are practically indistinguishable from those for finite-size clouds with arbitrary geometrical shapes.Comment: ApJ, to be publishe

    Preliminary results from the COLA N sample

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    We present preliminary radio imaging results for the northern COLA (Compact Objects in Low power AGN) sample. COLA is a large sample of moderate luminosity 10 ≤ log(L_(FIR)/L_☉) ≤ 12 infra-red selected galaxies. Our primary aim is to investigate possible connections between starburst activity and AGN. The sample has been observed in a variety of wavebands searching for correlations between AGN presence, galactic structure, gas content or degree of interaction. VLA A-array observations of half of the Northern sample are presented. From this data we find, consistent with previous studies, an anti-correlation between FIR luminosity and radio size. Unexpectedly we find that amongst sources which lie slightly above the radio-IR correlation, the excess radio emission is mostly in large scale structure (≥ 1kpc). Studies of the southern COLA sample suggest a strong correlation between having a radio excess and the presence of a compact AGN core, even though the core itself only accounts for small fraction of the excess. We speculate that either the bulk of AGN radio emission is on unexpectedly large scales or that AGN presence is correlated with old starbursts; a result consistent with proposed evolutionary models

    Addicted to Punishment: The Disproportionality of Drug Laws in Latin America

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    In Latin America, trafficking cocaine so it can be sold to someone who wants to use it is more serious than raping a woman or deliberately killingyour neighbor. While it may seem incredible, that is the conclusion of arigorous study of the evolution of criminal legislation in the region, which shows that countries' judicial systems mete out harsher penalties for traffickingeven modest amounts of drugs than for acts as heinous as sexua lassault or murder.How have we reached such an unjust and irrational point? In recent decades, especially the 1980s, Latin American countries, influenced by aninternational prohibitionist model, fell -- ironically -- into what we mightmetaphorically call an addiction to punishment.Addiction creates the need to consume more and more drugs, whichhave less and less effect; ultimately, the problematic user simply consumesdrugs to avoid withdrawal. Drug legislation in Latin America seems to have followed a similar path. Countries have an ever-growing need to add crimes and increase the penalties for drug trafficking, supposedly to control an expanding illegal market, while this increasingly punitive approach has less and less effect on decreasing the supply and use of illegal drugs.This report explores whether the recent evolution of criminal legislation in Latin American countries with regard to drug-related conducts respects these minimal guarantees to which criminal law should be subject, and especially whether that criminal legislation can be considered proportionate to the harm caused by prohibited conducts. Ultimately, the question is whether the crimes and punishments outlined in national legislation are proportionate. If the answer is no, the conclusion should be that they may even be unconstitutional within the framework of a constitutional state.To address this question, the report explores the recent development of criminal laws on drug-related crime in seven Latin American countries: Argentina, Bolivia, Brazil, Ecuador, Colombia, Peru and Mexico. These countries were chosen based on two basic criteria. First, they are of academic importance, because they have different drug-related problems, different geographic locations, diverse contexts and different political systems. According to traditional categorization, Colombia, Peru and Bolivia are considered producer countries; Mexico and even Brazil are considered trans-shipment countries. They also represent the different regions of Latin America,from the Southern Cone to the furthest Spanish-speaking country in North America.This report has three main parts. The first provides a conceptual and methodological overview of the elements that form the basis of the analysis.The second describes the principal recent trends in criminal drug legislation in Latin America. The third analyzes the proportionality of drug-related crimes and punishment in the countries, comparing them with penalties for other serious crimes, followed by some conclusions

    The missing future: Colombian youth

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    Includes bibliographyAnaliza los problemas de la juventud colombiana en relación con el desarrollo, el empleo, la educación, la participación política y las migraciones

    Structural and Energetic Characterization of the Ankyrin Repeat Protein Family

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    Ankyrin repeat containing proteins are one of the most abundant solenoid folds. Usually implicated in specific protein-protein interactions, these proteins are readily amenable for design, with promising biotechnological and biomedical applications. Studying repeat protein families presents technical challenges due to the high sequence divergence among the repeating units. We developed and applied a systematic method to consistently identify and annotate the structural repetitions over the members of the complete Ankyrin Repeat Protein Family, with increased sensitivity over previous studies. We statistically characterized the number of repeats, the folding of the repeat-arrays, their structural variations, insertions and deletions. An energetic analysis of the local frustration patterns reveal the basic features underlying fold stability and its relation to the functional binding regions. We found a strong linear correlation between the conservation of the energetic features in the repeat arrays and their sequence variations, and discuss new insights into the organization and function of these ubiquitous proteins.Fil: Parra, Rodrigo Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Espada, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Verstraete, Nina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Ferreiro, Diego Ulises. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

    Novel Antioxidant Therapy Against Myocardial Ischemia– Reperfusion Injury During Percutaneous Coronary Angioplasty

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    Acute myocardial infarction (AMI) is the leading cause of mortality worldwide. Major advances in the treatment have included coronary interventions, such as systemic thrombolysis and percutaneous coronary angioplasty (PCA). These procedures have been aimed to recover the blood flow in the cardiac zones affected by the occlusion of a branch of the coronary artery. However, damage is generated in the heart tissue known as myocardial reperfusion injury, an event associated with increased oxidative stress. Reactive oxygen species (ROS) are able to trigger cell death pathways, and myocardial structural and functional impairment. Studies on animal models of AMI suggest that lethal reperfusion accounts for up to 50% of the final size of a myocardial infarct, a part of the damage likely to be prevented. Although a number of strategies have been aimed to ameliorate lethal reperfusion injury, up to date the beneficial effects in clinical settings remain elusive. The accumulated body of evidence suggests that redox balance is a crucial determinant of ischemia–reperfusion injury, with clear mechanistic insights into pharmacological approaches. This chapter presents the molecular basis for a novel cardioprotection of patients with AMI subjected to PCA, based on a reinforcement of the antioxidant system

    Protein Repeats from First Principles

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    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family.Fil: Turjanski, Pablo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; ArgentinaFil: Parra, Rodrigo Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Espada, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Becher, Veronica Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; ArgentinaFil: Ferreiro, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

    Huella empresarial tolimense

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    146 p. Recuros ElectrónicoEl estudio de la historia empresarial es muy reciente en nuestro país y son pocos los investigadores que se dedican a profundizar en este tema. Sin embargo, es importante señalar que algunas instituciones académicas han empezado a mostrar interés por el estudio y la investigación en ésta temática, con el ánimo de explorar sobre el legado industrial que han dejado algunos empresarios. Estas circunstancias han provocado reformas en currículos para incorporar cursos de historia empresarial en los planes de estudio de los programas de las facultades de Ciencias Económicas y Administrativas, y en especial en los programas de Administración de Empresa
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