The Geometry of Crashes - A Measure of the Dynamics of Stock Market Crises

This paper investigates the dynamics of stocks in the S&P500 index for the last 30 years. Using a stochastic geometry technique, we investigate the evolution of the market space and define a new measure for that purpose, which is a robust index of the dynamics of the market structure and provides information on the intensity and the sectoral impact of the crises. With this measure, we analyze the effects of some extreme phenomena on the geometry of the market. Nine crashes between 1987 and 2001 are compared by looking at the way they modify the shape of the manifold that describes the S&P500 market space. These crises are identified as (a) structural, (b) general and (c) local.financial markets; stochastic geometry; complexity; market spaces; market structures.

The Seismography of Crashes in Financial Markets

This paper investigates the dynamics of stocks in the S&P500 for the last 33 years, considering the population of all companies present in the index for the whole period. Using a stochastic geometry tech- nique and defining a robust index of the dynamics of the market struc- ture, which is able to provide information about the intensity of the crises, the paper proposes a seismographic classification of the crashes that occurred during the period. The index is used in order to inves- tigate and to classify the impact of the twelve crashes between July 1973 and March 2006 and to discuss the available evidence of change of structure after the fin de sicle.Keywords: financial markets; stochastic geometry; complexity; market spaces; market structures.

Type III Secretion Effectors with Arginine N-Glycosyltransferase Activity

Type III secretion systems are used by many Gram-negative bacterial pathogens to inject proteins, known as effectors, into the cytosol of host cells. These virulence factors interfere with a diverse array of host signal transduction pathways and cellular processes. Many effectors have catalytic activities to promote post-translational modifications of host proteins. This review focuses on a family of effectors with glycosyltransferase activity that catalyze addition of N-acetyl-d-glucosamine to specific arginine residues in target proteins, leading to reduced NF-κB pathway activation and impaired host cell death. This family includes NleB from Citrobacter rodentium, NleB1 and NleB2 from enteropathogenic and enterohemorrhagic Escherichia coli, and SseK1, SseK2, and SseK3 from Salmonella enterica. First, we place these effectors in the general framework of the glycosyltransferase superfamily and in the particular context of the role of glycosylation in bacterial pathogenesis. Then, we provide detailed information about currently known members of this family, their role in virulence, and their targetsSpanish Ministerio de Economía, Industria y Competitividad , Agencia Estatal de Investigación, and the European Regional Development Fund, grant number SAF2016‐75365‐REuropean Union’s Horizon 2020 e Marie Skłodowska‐Curie grant agreement No 84262

Wind reversals and non-Oberbeck-Boussinesq effects in Rayleigh-Bénard convection

Convection, from the Latin convehere (to carry with), is the transport of a\ud physical quantity by coupling with a velocity field. Thermal convection,\ud in particular, is concerned with the interplay between heat, buoyancy, and\ud fluid motion. A classical example is provided by the emissions of warm\ud rising and cold falling fluid in a container heated from below and cooled\ud fromabove. Depending on the strength of the thermal driving, such emissions\ud may even induce a large-scale circulation of fluid. Some basic questions\ud arising in this scenario are: How irregular is the spatiotemporal dynamics\ud of the large-scale circulation? Does it exhibit any trace of long\ud memory? How sensitive is the flow to variations in the intrinsic properties\ud of the fluid? Are such changes capable of breaking the top-down symmetry\ud of the boundary-layers? These questions are addressed in the present\ud thesis

Structural changes in exchange rate regimes in Brazil

Following a dramatic breakdown of a managed floating regime, Brazil adopted a framework for policy consisting of inflation targeting and floating exchange rates. The country's commitment to this arrangement, however, is often put to dispute. In this paper we revisit the issue of whether Brazil has truly accepted to let its currency float, taking use of cross-currency linear regression models complemented by inferential techniques for evaluating the stability of exchange rate regimes. The results found suggest that Brazil does seem to have shifted towards greater exchange rate flexibility after the abandonment of its dollar-peg. However, after the adoption of inflation targeting the degree of exchange rate flexibility seems to have reduced a little.Structural changes; exchange rate regimes; emerging markets.

Brazilian Land Tenure and Conflicts: The Landless Peasants' Movement

This paper analyzes conflicts and violence in Brazil involving landless peasants occupying privately-owned land, for the period 2000-2008. It is the first study to be undertaken at a national level, with a contemporary data span, using a count data model that allows for heterogeneity, endogeneity and dynamics. Results from the estimated model show that the violent land occupation grows with left-wing political support for land occupation, rural population density, and agricultural credit, and decreases with poverty, agricultural productivity. The study discusses the interconnection of land reform, poverty and conflict.Land occupation, land reform, Brazil, poverty, conflict.

Economic Determinants of Driver's Behavior in Minas Gerais

The aim of the paper is to evaluate the behavior of drivers when they face a safe-traffic environment. Some studies suggest that the laws that demand auto makers to produce safer vehicles also stimulate their drivers to drive carelessly, since the cost of driving carefully decreases. Likewise, a safer traffic environment or less dangerous surroundings can stimulate drivers to drive more aggressively and less carefully. This study tries to test whether the undesirable behavior described by Peltzman (1975) is observed on the highways and roads of the State of Minas Gerais, Brazil. Estimates based on data found in the Brazilian Federal Road Police's accident report databank confirm drivers'' lack of attention in safer environments. The results suggest that careless behavior in traffic increases when safer conditions prevail.