Rational design of a bacterial transcriptional cascade for amplifying gene expression capacity

Cascade regulatory circuits have been described that control numerous cell processes, and may provide models for the design of artificial circuits with novel properties. Here we describe the design of a transcriptional regulatory cascade to amplify the cell response to a given signal. We used the salicylate-responsive activators of Pseudomonas putida NahR of the naphthalene degradation plasmid NAH7 and XylS2, a mutant regulator of the TOL plasmid for catabolism of m-xylene and their respective cognate promoters Psal and Pm. Control of the expression of xylS2 with the nahR/Psal system permitted either their selective activation with specific effectors for each protein or the simultaneous activation of both of them with salicylate. When cells face the common effector of the two regulators, both the increase in XylS2 concentration and the stimulation of its activity act synergistically on the Pm promoter, amplifying the gene expression capacity by at least one order of magnitude with respect to the individual systems. By changing the hierarchy of regulators, we showed that the specific features of the downstream regulator were crucial for the amplification effect. Directed changes in the effector profile of the regulators allowed the extension of the amplifying system to other molecular signals.

Rational interleukin 2 therapy for HIV positive individuals: daily low doses enhance immune function without toxicity.

When administered in high doses to HIV positive (HIV+) individuals, interleukin 2 (IL-2) causes extreme toxicity and markedly increases plasma HIV levels. Integration of the information from the structure-activity relationships of the IL-2 receptor interaction, the cellular distribution of the different classes of IL-2 receptors, and the pharmacokinetics of IL-2 provides for the rationale that low IL-2 doses should circumvent toxicity. Therefore, to identify a nontoxic, but effective and safe IL-2 treatment regimen that does not stimulate viral replication, doses of IL-2 from 62,500 to 250,000 IU/m2/day were administered subcutaneously for 6 months to 16 HIV+ individuals with 200-500 CD4+ T cells/mm3. IL-2 was already detectable in the plasma of most HIV+ individuals even before therapy. Peak plasma IL-2 levels were near saturating for high affinity IL-2 receptors in 10 individuals who received the maximum nontoxic dose, which ranged from 187,500 to 250,000 IU/m2/day. During the 6 months of treatment at this dose range, plasma levels of proinflammatory cytokines remained undetectable, and plasma HIV RNA levels did not change significantly. However, delayed type hypersensitivity responses to common recall antigens were markedly augmented, and there were IL-2 dose-dependent increases in circulating Natural Killer cells, eosinophils, monocytes, and CD4+ T cells. Expanded clinical trials of low dose IL-2 are now warranted, especially in combination with effective antivirals to test for the prevention of immunodeficiency and the emergence of drug-resistant mutants and for the eradication of residual virions.

Olfactory transduction is intrinsically noisy.

The sources of noise that limit olfactory signal detection were investigated in dissociated rat olfactory receptor cells. Near-threshold odorant-evoked currents exhibited large random fluctuation. However, similar fluctuations were observed in the absence of applied odorants when currents were induced by elevating the intracellular cyclic AMP concentration. This suggests that the fluctuations reflect noise intrinsic to the transduction mechanism, rather than the quantal nature of an odorant stimulus. For many odorants, this intrinsic noise may preclude the reliable detection of single odorant molecules.

Legislação e judiciatura: o lugar da lei na realização judicial do direito

O presente trabalho questiona o papel da legislação na realização judicial do direito. Para responder a essa questão, empreende-se uma tese conceitual sobre a dinâmica jurídica, que pretende superar a tradicional dicotomia entre a legislação e a função judicial concebida pela doutrina clássica da separação dos poderes. De acordo com a argumentação desenvolvida aqui, o judiciário julga não somente fatos dos casos, mas também as próprias escolhas legislativas, de modo que já não é possível defender que a função judicial consiste em mera declaração da lei nos casos particulares ou ainda em subsunção lógica das lides que lhe são submetidas às normas previamente postas pelo processo legislativo. Assim, a realização judicial do direito não pode ser anteriormente determinada, uma vez que não está condicionada pelo conteúdo legislado. Contudo, os conteúdos da lei transmitem algum sentido para os cidadãos e, por isso, criam expectativas. Confirmar ou não essas expectativas é uma questão relacionada com a justificação e a legitimidade dos Estados racionais modernos, que estabelecem com os cidadãos uma relação de dominação legal-racional. Desse modo, a questão do papel da legislação (direito positivo passado) na realização do direito atual é posta em termos de legitimidade. Se, de um lado, constatamos que não é possível pretender controlar a discricionariedade judicial dentro dos próprios limites do direito, de outro lado defendemos que é legítimo pretender submeter o direito positivo à crítica e ao controle democrático. Isso porque interessa a todos os cidadãos que as decisões judiciais possam ser justificadas de modo razoável, graças a uma argumentação cuja força e a pertinência se reconheçam amplamente na sociedade. A partir dessa perspectiva, propomos um redimensionamento do argumento legal na prática jurídica e passamos a analisar as diversas implicações da questão central posta neste trabalho na realização judicial do direito.

Robust fitting of Zernike polynomials to noisy point clouds defined over connected domains of arbitrary shape

A new method for fitting a series of Zernike polynomials to point clouds defined over connected domains of arbitrary shape defined within the unit circle is presented in this work. The method is based on the application of machine learning fitting techniques by constructing an extended training set in order to ensure the smooth variation of local curvature over the whole domain. Therefore this technique is best suited for fitting points corresponding to ophthalmic lenses surfaces, particularly progressive power ones, in non-regular domains. We have tested our method by fitting numerical and real surfaces reaching an accuracy of 1 micron in elevation and 0.1 D in local curvature in agreement with the customary tolerances in the ophthalmic manufacturing industry.

On the forecast accuracy and consistency of exchange rate expectations: The Spanish PwC Survey.

We examine the predictive ability and consistency properties of exchange rate expectations for the dollar/euro using a survey conducted in Spain by PwC among a panel of experts and entrepreneurs. Our results suggest that the PwC panel have some forecasting ability for time horizons from 3 to 9 months, although only for the 3-month ahead expectations we obtain marginal evidence of unbiasedness and efficiency in the forecasts. As for the consistency properties of the exchange rate expectations formation process, we find that survey participants form stabilising expectations in the short-run and destabilising expectations in the long- run and that the expectation formation process is closer to fundamentalists than chartists.

Role Expectations and State Socialization: Germany's Rediscovery of the Use of Force 1990-1995

This dissertation engages the question of why German political elites accepted the use of force during the 1990s and started to commit the country's armed forces to multilateral peacekeeping missions. Previous governments of the Federal Republic had opposed foreign deployment of the military and Germany was characterized by a unique strategic culture in which the efficacy of military force was widely regarded as negative. The rediscovery of the use of force constituted a significant reorientation of German security policy with potentially profound implications for international relations. I use social role theory to explain Germany's security policy reorientation. I argue that political elites shared a national role conception of their country as a dependable and reliable ally. Role expectations of the international security environment changed as a result of a general shift to multilateral intervention as means to address emerging security problems after the Cold War. Germany's resistance to the use of force was viewed as inappropriate conduct for a power possessing the economic and military wherewithal of the Federal Republic. Elites from allied countries exerted social pressure to have Germany contribute commensurate with capabilities. German political elites adapted role behavior in response to external expectations in an effort to preserve the national role conception of a dependable and reliable ally. Security policy reorientation to maintain Germany's national role conception was pursued by conservative elites who acted as 'role entrepreneurs'. CDU/CSU politicians initiated a process of role adaptation to include the use of force for non-defensive missions. They persuaded Social Democrats and Alliance 90/Green party politicians that the maintenance of the country's role conception necessitated a reorientation in security policy to accommodate the changes in the security environment.

Successful Navigation of the Conflict between Doctoral Education and Cultural Expectations of Child Rearing in Hispanic Culture

While the numbers are slowly rising, Hispanic students continue to be disproportionately underrepresented in all levels of higher education, including doctoral education. There are many factors that may contribute to the low numbers of Hispanic doctoral students; for Hispanic women, one of these factors may be the perceived conflict between cultural expectations of childrearing and doctoral education. For Hispanic students who hold strong cultural values, this conflict may prevent enrollment in, or result in attrition from, doctoral education. As the number of Hispanic college enrollment increases, we will see more students trying to navigate between the collectivistic value of childrearing and the individualistic value of pursuing higher education. Thus, it is important to understand the needs of these students to aid in recruitment and retention of student-parents in all levels of higher education. This paper explores the barriers and supportive factors for current Hispanic doctoral student-parents. Suggestions are made to increase support which will allow these individuals to successfully complete a doctoral education, while attending to the responsibilities of parenting.

Removing noisy mentions for distant supervision

Los métodos para Extracción de Información basados en la Supervisión a Distancia se basan en usar tuplas correctas para adquirir menciones de esas tuplas, y así entrenar un sistema tradicional de extracción de información supervisado. En este artículo analizamos las fuentes de ruido en las menciones, y exploramos métodos sencillos para filtrar menciones ruidosas. Los resultados demuestran que combinando el filtrado de tuplas por frecuencia, la información mutua y la eliminación de menciones lejos de los centroides de sus respectivas etiquetas mejora los resultados de dos modelos de extracción de información significativamente.

Improving 3D Keypoint Detection from Noisy Data Using Growing Neural Gas

3D sensors provides valuable information for mobile robotic tasks like scene classification or object recognition, but these sensors often produce noisy data that makes impossible applying classical keypoint detection and feature extraction techniques. Therefore, noise removal and downsampling have become essential steps in 3D data processing. In this work, we propose the use of a 3D filtering and down-sampling technique based on a Growing Neural Gas (GNG) network. GNG method is able to deal with outliers presents in the input data. These features allows to represent 3D spaces, obtaining an induced Delaunay Triangulation of the input space. Experiments show how the state-of-the-art keypoint detectors improve their performance using GNG output representation as input data. Descriptors extracted on improved keypoints perform better matching in robotics applications as 3D scene registration.