Bargaining and sustainability: the Argentine debt swap of 2005

When Argentine sovereign default in December 2001 led to a collapse of the peso, the burden of dollar debt became demonstrably unsustainable. But it was not clear what restructuring was feasible, nor when. Eventually, in 2005 after a delay of more than three years, a supermajority of creditors accepted a swap implying a recovery rate of around 37 cents in the dollar. In this paper a bargaining approach is used to explain both the settlement and the delay. We conclude that the agreed swap broadly corresponds to a bargaining outcome where the Argentine government had “first mover” advantage: and that substantial delay occurred as negotiators seeking a sustainable settlement waited for economic recovery. Factors not explicit in the formal framework are also considered -- heterogeneity of creditors, for example, and the role of third parties in promoting “good faith” bargaining

Contractionary devaluation and credit crunch: analysing Argentina

Sharp economic contraction often follows currency devaluation in emerging markets - due mainly to liability dollarisation. Such adverse balance sheet effects play a key role in the well-known model of Aghio et al (2000), by reducing investment and future supply. We show how the prompt contraction of output can be accounted for by incorporating demand failure - due to a slow export response and a credit crunch. The resulting eclectic framework is used to study the collapse of the Argentine economy when Convertibility ended in 2002; and to see why efforts to imitate President Roosevelt by 'pesifying' the economy proved counter-productive

Exact and heuristic methods for solving the Robotic Assembly Line Balancing Problem

[EN] In robotic assembly lines, the task times depend on the robots assigned to each station. Robots are considered an unlimited resource and multiple robots of the same type can be assigned to different stations. Thus, the Robotic Assembly Line Balancing Problem (RALBP) consists of assigning a set of tasks and a type of robot to each station, subject to precedence constraints between the tasks. This paper proposes a lower bound, and exact and heuristic algorithms for the RALBP. The lower bound uses chain decomposition to explore the graph dependencies. The exact approaches include a novel linear mixed-integer programming model and a branch-bound-and-remember algorithm with problem-specific dominance rules. The heuristic solution is an iterative beam search with the same rules. To fully explore the different characteristics of the problem, we also propose a new set of instances. The methods and algorithms are extensively tested in computational experiments showing that they are competitive with the current state of the art. (C) 2018 Elsevier B.V. All rights reserved.Borba, L.; Ritt, M.; Miralles Insa, CJ. (2018). Exact and heuristic methods for solving the Robotic Assembly Line Balancing Problem. European Journal of Operational Research. 270(1):146-156. https://doi.org/10.1016/j.ejor.2018.03.011S146156270

Supply shocks and currency crises: the policy dilemma reconsidered

The stylised facts of currency crises in emerging markets include output contraction coming hard on the heels of devaluation, with a prominent role for the adverse balance-sheet effects of liability dollarisation. In the light of the South East Asian experience, we propose an eclectic blend of the supply-side account of Aghion, Bacchetta and Banerjee (2000) with a demand recession triggered by balance sheet effects (Krugman, 1999). This sharpens the dilemma facing the monetary authorities - how to defend the currency without depressing the economy. But, with credible commitment or complementary policy actions, excessive output losses can, in principle, be avoided

Strain-Tunable GaAs Quantum dot: A Nearly Dephasing-Free Source of Entangled Photon Pairs on Demand

Entangled photon generation from semiconductor quantum dots via the biexciton-exciton cascade underlies various decoherence mechanisms related to the solid-state nature of the quantum emitters. So far, this has prevented the demonstration of nearly-maximally entangled photons without the aid of inefficient and complex post-selection techniques that are hardly suitable for quantum communication technologies. Here, we tackle this challenge using strain-tunable GaAs quantum dots driven under two-photon resonant excitation and with strictly-degenerate exciton states. We demonstrate experimentally that our on-demand source generates polarization-entangled photons with fidelity of 0.978(5) and concurrence of 0.97(1) without resorting to post-selection techniques. Moreover, we show that the remaining decoherence mechanisms can be overcome using a modest Purcell enhancement so as to achieve a degree of entanglement >0.99. Our results highlight that GaAs quantum dots can be readily used in advanced communication protocols relying on the non-local properties of quantum entanglement

Synthesis of novel O-acylated-D-ribono-1,5-lactones and structural assignment supported by conventional NOESY-NMR and x-ray analysis

A practical method for the structural assignment of 3,4-O-benzylidene-D-ribono-1,5-lactones and analogues using conventional NMR techniques and NOESY measurements in solution is described. 2-O-Acyl-3,4-O-benzylidene-D-ribono-1,5-lactones were prepared in good yields by acylation of Zinner’s lactone with acyl chlorides under mildly basic conditions. Structural determination of 2-O-(4-nitrobenzoyl)-3,4-O-benzylidene-D-ribono-1,5-lactone was achieved by single crystal x-ray diffraction, which supports the results based on spectroscopic data.Este trabalho apresenta um método simples para a caracterização estrutural de 3,4-O-benzilideno-D-ribono-1,5-lactonas e análogos, fundamentado em técnicas convencionais de RMN e experimentos de NOESY em solução. 2-O-Acil-3,4-O-benzilideno-D-ribono-1,5-lactonas foram preparadas em bons rendimentos a partir da acilação das lactonas de Zinner empregando cloretos de ácido sob condições básicas. A estrutura de 2-O-(4-nitrobenzoil)-3,4-O-benzilideno-D-ribono-1,5-lactona foi determinada por difração de raios-X e confirmou, de forma inequívoca, os dados espectroscópicos obtidos.CNPq - MC

Pigmento de titânio em tecidos de toxicômanos: relatos de cinco casos necropsiados

O objetivo deste relato é descrever os achados anatomopatológicos de cinco casos de toxicômanos com pigmento de titânio em vários órgãos, após injeção de comprimidos esmagados de cloridrato de propoxifeno. Foram obtidos fragmentos do fígado, baço, pulmões, linfonodos e medula óssea e, após a avaliação macroscópica, amostras foram submetidas à microscopia de luz comum e de luz polarizada. Em todos os cinco casos, foi encontrado um pigmento com características de dióxido de titânio nas amostras dos órgãos estudados. Nossos achados sugerem que a pesquisa sobre pigmento de titânio em tecidos corporais deva ser complementada, considerando-se a contribuição de dados morfológicos em Patologia Forense.The aim of this report is to describe the anatomic-pathologic findings from necropsies of 5 drug addicts with titanium pigment in several organs after chronic intravenous injection of crushed propoxyphene hydrochloride tablets. Samples from liver, spleen, lungs, lymph nodes, and bone marrow were obtained, and after being grossly studied, they were submitted to evaluation using common light and polarized microscopy. In all 5 cases, a pigment with characteristics of titanium dioxide was found within tissue samples of the organs studied. Our findings suggest that research concerning titanium pigment within body tissues should be enhanced, considering the potential contribution of this morphologic data to forensic pathology

Definition of the Viral Targets of Protective HIV-1-Specific T Cell Responses

Background: The efficacy of the CTL component of a future HIV-1 vaccine will depend on the induction ofresponses with the most potent antiviral activity and broad HLA class I restriction. However, current HIV vaccinedesigns are largely based on viral sequence alignments only, not incorporating experimental data on T cellfunction and specificity. Methods: Here, 950 untreated HIV-1 clade B or -C infected individuals were tested for responses to sets of 410overlapping peptides (OLP) spanning the entire HIV-1 proteome. For each OLP, a “protective ratio” (PR) wascalculated as the ratio of median viral loads (VL) between OLP non-responders and responders. Results: For both clades, there was a negative relationship between the PR and the entropy of the OLP sequence.There was also a significant additive effect of multiple responses to beneficial OLP. Responses to beneficial OLPwere of significantly higher functional avidity than responses to non-beneficial OLP. They also had superior in-vitroantiviral activities and, importantly, were at least as predictive of individuals’ viral loads than their HLA class Igenotypes. Conclusions: The data thus identify immunogen sequence candidates for HIV and provide an approach for T cellimmunogen design applicable to other viral infections