Keeping Communism Down on the Farm: The Brazilian Rural Labor Movement during the Cold War

Drawing on primary and secondary sources, this article discusses the durability of communist ideology in rural Brazil during the second half of the twentieth century. It analyzes the theme in two major periods: the Populist Republic (1945–1964) and the Military Regime (1964–1985). Concluding with a discussion of the first years of the New Republic, it argues that the political mobilization of Brazilian peasants defied the geopolitical logic of the era, which dictated the elimination of communist thought by the conclusion of the cold war

MOVEMENT HISTORIES: A PRELIMINARY HISTORIOGRAPHY OF THE BRAZIL’S LANDLESS LABORERS’ MOVEMENT (MST)

Founded in 1984, the Landless Rural Workers Movement of Brazil (MST) has been historicized in several recent publications. This review essay examines seven books that provide historical analysis of the movement. Published in English, Spanish, Portuguese, and Italian in the past six years, these books offer diverse assessments of MST history. The essay contrasts their interpretations of the movement’s origins, founding, consolidation, organization, and future prospects. As an institutionalized social movement with more than twenty years of history, the books prove that the MST merits the attention of historians

Peruvian birds.

27 p. ; 24 cm.Includes bibliographical references

Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System

Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations, while meeting crew and vehicle safety requirements. The analyses and associated testing presented here surround a second generation of the airbag design developed by ILC Dover, building off of relevant first-generation design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley s Landing and Impact Research (LandIR) facility in Hampton, Virginia. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, develop the simulations, and make comparisons to experimental data are discussed

Allomorphy as a mechanism of post-translational control of enzyme activity

Enzyme regulation is vital for metabolic adaptability in living systems. Fine control of enzyme activity is often delivered through post-translational mechanisms, such as allostery or allokairy. β-phosphoglucomutase (βPGM) from Lactococcus lactis is a phosphoryl transfer enzyme required for complete catabolism of trehalose and maltose, through the isomerisation of β-glucose 1-phosphate to glucose 6-phosphate via β-glucose 1,6-bisphosphate. Surprisingly for a gatekeeper of glycolysis, no fine control mechanism of βPGM has yet been reported. Herein, we describe allomorphy, a post-translational control mechanism of enzyme activity. In βPGM, isomerisation of the K145-P146 peptide bond results in the population of two conformers that have different activities owing to repositioning of the K145 sidechain. In vivo phosphorylating agents, such as fructose 1,6-bisphosphate, generate phosphorylated forms of both conformers, leading to a lag phase in activity until the more active phosphorylated conformer dominates. In contrast, the reaction intermediate β-glucose 1,6-bisphosphate, whose concentration depends on the β-glucose 1-phosphate concentration, couples the conformational switch and the phosphorylation step, resulting in the rapid generation of the more active phosphorylated conformer. In enabling different behaviours for different allomorphic activators, allomorphy allows an organism to maximise its responsiveness to environmental changes while minimising the diversion of valuable metabolites