Spatial implications of international trade under the new economic geography approach

In 2008, Paul Krugman from Princeton University was awarded the Nobel Prize in Economic Sciences by the Central Bank of Sweden, for his “analysis of trade patterns and location of economic activity”. In this paper we survey the literature, known as the New Economic Geography (NEG), launched by Krugman (1991). In particular, we focus on four topics: (i) NEG roots, (ii) NEG rationale; (ii) the spatial impact of international trade on global economic imbalances; and (iv) the impact of international trade on urban structure.New Economic Geography; Trade Openness; Agglomeration and Urban Economics.

An Energy-Based Approach to Satellite Attitude Control

The aim of this paper is to present a novel control strategy of the satellite attitude control problem on an energy-based setting. Controlling the orientation with respect to an inertial frame of reference becomes challenging in presence of nonlinear disturbances such as the gravity-gradient torque. We make use of the advantages of representing the system under study via the port-Hamiltonian framework due to its clear control design philosophy. The key strategies depend on position and velocity measurements, together with and integral action of the system's output. Finally, numerical simulation results are provided to demonstrate effectiveness

Designer Exons Inform a Biophysical Model for Exon Definition

Pre-mRNA molecules in humans contain mostly short internal exons flanked by long introns. To explain the removal of such introns, recognition of the exons instead of recognition of the introns has been proposed. This thesis studies this exon definition mechanism using a bottom-up approach. To reduce the complexity of the system under study, this exon definition mechanism was addressed using designer exons made up of prototype sequence modules of our own design (including an exonic splicing enhancer or silencer). Studies were performed in vitro with a set of DEs obtained from random combinations of the exonic splicing enhancer and the exonic splicing silencer modules. The results showed considerable variability both in terms of the composition and size of the DEs and in terms of their inclusion level. To understand how different DEs generated different inclusion levels, the problem was divided into understanding separately parameters varied between DEs. Subsequent studies focused on each of three parameters: size, ESE composition and ESS composition. The final objective was to be able to combine their effects to predict the inclusion levels obtained for the "random" DEs mentioned previously. To complement this experimental approach an equation was generated in two stages. First a general "framework" equation was obtained modeling a necessary exon definition complex that enabled commitment to inclusion. This equation used rates for the formation and dissociation of this complex without elaborating on the details for how those rates came about. In the second stage, however, formation and dissociation were modeled using novel but intuitive ideas and these models were combined into a final equation. This equation using the single-parameter perturbation data obtained previously performed well in predicting the inclusion levels of the "random" DEs. Additionally, both the final equation and the mechanisms proposed align well with results published by other groups. In order to make these results more accessible and to open more opportunities to extend them, an initial attempt is presented to identify the proteins involved in the functionality observed for each of the sequences used

Presentación atípica de dolor abdominal y fiebre en paciente positivo para COVID19. Reporte de caso y revisión de la literatura.: Atypical presentation of abdominal pain and fever in positive patient for COVID19. Case report and literature review

The clinical case of a 38-year-old female patient, seen in an emergency room in a New York hospital, who consults for abdominal pain, fever and fatigue is presented. Complementary studies show lymphopenia and slight alteration of transaminases. Abdominopelvic CT scan visualizes images in the lung bases, reticulonodular type. A sample was taken for COVID-19. She was managed in emergencies with parenteral hydration, antipyretics, oral antibiotics are indicated and social isolation measures are instructed. Two days later, it cost again, confirming positive COVID-19. It is followed on an outpatient basis, one week later with good clinical evolution. Additionally, a clinical review and pathophysiological explanation of the involvement of the digestive tract by the virus and the atypical form of presentation with abdominal pain are shown.Se presenta el caso clínico de una paciente femenino de 38 años de edad, vista en emergencia en un hospital de New York, que consulta por dolor abdominal, fiebre y astenia. Los estudios complementarios muestran linfopenia y leve alteracion de transaminasas. Por TAC abdominopelvica, se visuliza imágenes en bases pulmonares, de tipo reticulonodular. Se le tomó muestra para COVID-19. Fue manejada en emergencias con hidratacion parenteral, antipireticos, se le indica antibioticos por via oral y se instruye medidas sociales de aislamiento. Dos dias despues, cosulta nuevamente, confirmadose COVID-19 positivo. Es seguida de manera ambulatoria, una semana despues con buena evolucion clinica. Adicionalmente se muestra una revision clínica y explicacion fisiopatologica del compromiso del tubo digestivo por el virus y la forma atipica de presentacion con dolor abdominal

Exact Maximum Likelihood Estimation of Stationary Vector ARMA Models

The problems of evaluating and maximizing the exact likelihood function of vector ARMA models are considered separately. A new and efficient procedure for evaluating the exact likelihood function is presented. This method puts together a set of useful features which can only be found separately in currently available algorithms. A procedure for maximizing the exact likelihood function, which takes full advantage of the properties offered by the evaluation algorithm, is also considered. Combining these two procedures, a new algorithm for exact maximum likelihood estimation of vector ARMA models is obtained. Comparisons with existing procedures, in terms of both analytical arguments and a numerical example, are given in order to show that the new estimation algorithm performs at least as well as existing ones, and that relevant real situations occur in which it do es better