Brazil has a monitoring system to track annual forest conversion in the Amazon and most recently to monitor the Cerrado biome. However, there is still a gap of annual land use and land cover (LULC) information in all Brazilian biomes in the country. Existing countrywide efforts to map land use and land cover lack regularly updates and high spatial resolution time-series data to better understand historical land use and land cover dynamics, and the subsequent impacts in the country biomes. In this study, we described a novel approach and the results achieved by a multi-disciplinary network called MapBiomas to reconstruct annual land use and land cover information between 1985 and 2017 for Brazil, based on random forest applied to Landsat archive using Google Earth Engine. We mapped five major classes: forest, non-forest natural formation, farming, non-vegetated areas, and water. These classes were broken into two sub-classification levels leading to the most comprehensive and detailed mapping for the country at a 30 m pixel resolution. The average overall accuracy of the land use and land cover time-series, based on a stratified random sample of 75,000 pixel locations, was 89% ranging from 73 to 95% in the biomes. The 33 years of LULC change data series revealed that Brazil lost 71 Mha of natural vegetation, mostly to cattle ranching and agriculture activities. Pasture expanded by 46% from 1985 to 2017, and agriculture by 172%, mostly replacing old pasture fields. We also identified that 86 Mha of the converted native vegetation was undergoing some level of regrowth. Several applications of the MapBiomas dataset are underway, suggesting that reconstructing historical land use and land cover change maps is useful for advancing the science and to guide social, economic and environmental policy decision-making processes in Brazil.

Forest degradation in the Brazilian Amazon due to selective logging and forest fires may greatly increase the human footprint beyond outright deforestation. We demonstrate a method to quantify annual deforestation and degradation simultaneously across the entire region for the years 2000-2010 using high-resolution Landsat satellite imagery. Combining spectral mixture analysis, normalized difference fraction index, and knowledge-based decision tree classification, we mapped and assessed the accuracy to quantify forest (0.97), deforestation (0.85) and forest degradation (0.82) with an overall accuracy of 0.92. We show that 169,074 km 2 of Amazonian forest was converted to human-dominated land uses, such as agriculture, from 2000 to 2010. In that same time frame, an additional 50,815 km 2 of forest was directly altered by timber harvesting and/or fire, equivalent to 30% of the area converted by deforestation. While average annual outright deforestation declined by 46%OPEN ACCESS

The treatment of soils with cement is an attractive technique when a project requires improvement of the local soil for the construction of subgrades for rail tracks, for roads, as a support layer for shallow foundations, and to prevent sand liquefaction. This paper advances understanding of the key parameters for the control of strength and stiffness of cemented soils by testing two soils with different gradings and quantifying the influence of porosity/cement ratio on both initial shear modulus (G 0 ) and unconfined compressive strength (q u ). It is shown that the porosity/cement ratio is an appropriate parameter to assess both the initial stiffness and the unconfined compressive strength of the soil-cement mixtures studied. Each soil matrix has a unique relationship for G 0 /q u against adjusted porosity/cement ratio, linking initial stiffness and strength.KEYWORDS: compaction; ground improvement; laboratory tests; sands; soil stabilisation; stiffness Le traitement des sols au ciment est une technique attrayante pour les projets nécessitant un renforcement du sol pour la construction d'assiettes pour voies ferrées et chaussées, comme couche d'appui pour fondations peu profondes, et pour la prévention de la liquéfaction du sable. La présente communication renforce les connaissances sur les principaux paramètres pour la régulation de la résistance et de la rigidité des sols cimentés, en soumettant à des essais deux sols de différentes granulométries, et en quantifiant l'influence du ratio porosité / ciment à la fois sur le module de cisaillement initial (G 0 ) et sur la résistance à la compression simple (q u ). On y montre que le ratio porosité /ciment est un paramètre approprié pour évaluer à la fois la rigidité initiale et la résistance à la compression simple des mélanges solciment étudiés. Chaque matrice de sol présente un G 0 /q u unique en fonction du ratio porosité /ciment, mettant en rapport la rigidité initiale et la résistance. INTRODUCTIONIn highway and other shallow constructions, cement is often used to improve local soils, for example to make them suitable as subgrades, formations and foundation backfill (e.g. Rattley et al., 2008;Consoli et al., 2009). Previous studies of soil-cement (Moore et al., 1970;Clough et al., 1981;Consoli et al., 2010Consoli et al., , 2011 have shown that its behaviour is complex, and affected by many factors, such as the physical-chemical properties of the soil, the amount of cement, and the porosity and moisture content at the time of compaction. Consoli et al. (2007) were the first to establish a unique dosage methodology based on rational criteria where the porosity/cement ratio plays a fundamental role in assessment of the target unconfined compressive strength.This study shows the influence of the amount of cement and the porosity on the initial shear modulus (G 0 ) and unconfined compressive strength (q u ) of two different soils: uniform Osorio sand and very well-graded Porto silty sand. EXPERIMENTAL PROGRAMME MaterialsThe results of characterisation tests on t...

The results from a laboratory testing programme designed to evaluate the behaviour of gold tailings are presented, and interpreted in the critical state framework. Drained and undrained triaxial tests sheared under monotonic loading allowed the critical state line (CSL) to be established. The observed highly non-linear shape of the CSL was used to investigate the intrinsic dynamics of the monotonic undrained response of tailings, and to define the undrained instability state. This behaviour is useful in explaining the mechanics of tailings, which exhibits relatively well-defined transitions of state captured by the state parameter.

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