Monitoring land use and plant cover on an integrated agroecological production system through GIS.

The objective of this paper is to study in detail the land use and plant cover of an Integrated Agroecological Production System (IAPS) from 2003 through 2005. Four quarterly updating visits were performed on the 26 land units of the System from January 2003 to December 2005. Cartographic documents and QuickBird satellite images were also used to generate the final index maps for agrodiversity, fallow intensity and green manure use intensity. A high diversity of crops was observed. In some land units up to 40 plant species were recorded. However, this diversity was not uniformly distributed throughout the terrain. A high intensity of land use, mostly with annuals was also observed in a large part of the area. In most cases, fallow periods were up to 3 months in 3 years. Since annual crops demand intense tillage, minimum or no tillage practices are recommended for those areas to improve soil conservation. The use of legumes was less frequent on the land units used for annual crops. They were not uniformly distributed throughout the terrain. The results of this research are useful not only for those who are interested in the system itself, but also to validate the hypothesis that through GIS it is possible to summarize complex agroecological information into a visually friendly format, allowing easy interpretation of systemic analyses

Monitoring fungal burden and viability of Sporothrix spp. in skin lesions of cats for predicting antifungal treatment response

Skin lesions in feline sporotrichosis usually present a high fungal burden, making cats an important source of infection. This study evaluated the fungal burden and isolation in skin lesions of feline sporotrichosis during treatment with itraconazole (ITZ), combined with or without potassium iodide (KI). Treatment-naïve cats with culture-confirmed sporotrichosis and presenting skin ulcers were treated for up to 40 weeks with oral ITZ alone (n = 74) or combined with KI (n = 56). These cats were submitted to monthly sampling of the same lesion for mycological culture and cytopathology until healing of lesion or up to twelve weeks. The fungal burden was expressed as the mean yeast cell count in three microscopic fields from imprint smears. The fungal burden before treatment was significantly higher in cats in which the lesion persisted and in cases of treatment failure when using ITZ alone. After twelve weeks, the median fungal burden decreased to zero in both treatment protocols, suggesting a potential decrease in the risk of transmission of Sporothrix spp. from cats. These findings encourage the early treatment of feline sporotrichosis as a control measure. Moreover, the fungal burden in feline sporotrichosis lesions can be a prognostic indicator and a parameter for choosing appropriate therapeutic regimen

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Aplicações do scanner hiperespectral Hymap como suporte à prospecção uranífera: estudo de caso na área do depósito metamórfico-hidrotermal de U-ETR Mary Kathleen, NW Queensland, Austrália

The Mary Kathleen (MK) metamorphic-hydrothermal U-REE deposit is located in NW Queensland, Australia and comprised in the Mount Isa Metamorphic Province. The area includes sedimentary (limestone, shales), volcanics (rhyolite, basalt, dacite) and intrusive rocks (granodiorite, porphyritic leucogranito), metamorphosed at greenschist to amphibolites facies. The MK deposit is associated with skarns enriched in U-REE. Such deposit type differs from other U deposits as it comprises specific calc-silicate alteration, intense garnetization and association to contact-metasomatic processes. In this study, hyperspectral signatures that can be used to vectorize U mineralizations are investigated. Data acquired by the HyMap hyperespectral sensor (128 bands between the visible-near infrared and shortwave infrared wavelengths 350-2500nm) were processed through a sequence of information extraction techniques aiming to reveal multiple, detailed mineral spatial distributions and abundances at the deposit scale. This approach rendered hyperspectral signatures of U ore-related and host rock minerals of the MK deposit. Some of the prime minerals, such as andradite, epidote, hornblende, calcite and scapolite, were plausibly detectable remotely. The spectral analysis also unveiled goethite, kaolinite and montmorilllonite within the mine pit and adjacent areas, which are minerals probably formed by weathering of the underlying, fresher rocks. Mineral abundance maps yielded from HyMap data processing with spectral unmizing algorithms were also combined as false color composite renditions. This strategy allowed the simultaneous enhancement of sites with dominant minerals and their mixtures, which can be widely applied to detailed U prospectivity mapping.Pages: 8668-867

Aplicações de Geotecnologias como subsídio para compilação do mapa de uso do solo no Parque Estadual da Pedra Branca

The mapping of the land use in a given area is fundamental to provide subsidies for environmental management. In this work, the procedures used to identify the land use of the study area were based on visual and interpretation of digital image. The use of soil of the conservation unit Parque Estadual da Pedra Branca was obtained by interpretation of a digital image Ikonos. The thematic map was generated using geographic information system. The area of the conservation unit is approximately 13.038 ha. The distribution of classes of land use identified in the conservation unit, it is observed that forestry fragment is predominate, class that occupies the large area, with 7.816 ha, approximately 60% of the total area. The class pertubation area cover an area 4.989 ha, or 38.38% of the total area. The map land use generated shown that the antropic influence is important factor of the perturbation of the conservation unit.Pages: 3898-390

New near-mine prospecting approach using multivariate analysis and reflectance spectroscopy to define surface footprint: A case study of the Pequizão Gold Deposit, Crixás Greenstone Belt, Central Brazil

The Pequizão gold deposit in the Crixás greenstone belt, central Brazil, is structurally-controlled mineralization hosted mainly in carbonaceous phyllite with pervasive hydrothermalized zones and large amounts of disseminated sulfides and gold. Usually, regoliths of Au deposits are either unstudied or understudied in exploration surveys because of lower Au content and the difficulty and complexity of soil profiles. However, such investi gation can be beneficial in brownfield exploration to assess larger areas than drilling. In this work, results of clustering and machine learning of soil geochemistry and reflectance spectroscopy integrated with a multivariate approach to determine soil footprints and to target new deposits in the surface of the Crixás greenstone belt. Reflectance spectroscopy was applied in 939 soil samples and is a valuable tool in mineral exploration for an immediate investigation of mineral assemblage from the target. It was calibrated with X-ray diffraction, geochemical, and multivariate approaches providing consistent vectors toward mineralization, with Pequizão soil samples developing gibbsite and phengitic-white mica as minerals related to mineralized samples. Multi variate analysis reveals that the deposit has a typical orogenic gold deposit chemical signature. Principal components and factor analysis first defined samples derived from carbonaceous phyllite and dolomite as the main ore hosts. The chemical aspects of hydrothermal alteration are As, Ag, Te, Ca, and Mg, with enrichment of Sb, V, Na, Ba, and W and depletion of Zn, Ga, and Pb that, according to ensemble learning, they have significant importance in the detection of gold. Understanding surface footprints of known deposits can be an exploratory guide for finding new soil geochemical halos related to mineralization zones. The research revealed new asso ciations of minerals and chemical elements that can be determined as exploration vectors. It was possible to clarify further the knowledge about the footprint of mineralization in soil. Combining the soil-related methods applied in this study and a broad-coverage spectral approach in soil and drill cores can enhance success in prospecting in brownfield areas and expand to greenfields.Instituto de Geociências (IG)Programa de Pós-Graduação em Geologi

Identifying high potential zones of gold mineralization in a sub-tropical region using Landsat-8 and ASTER remote sensing data: a case study of the Ngoura-Colomines goldfield, Eastern Cameroon

Climatic conditions and vegetation constrain the use of optical satellite imagery as an exploration tool for hydrothermal ore mineralization in tropical and subtropical regions. In this investigation, Landsat-8 and ASTER satellite imagery were used to detect hydrothermal alteration zones associated with gold mineralization in the Ngoura-Colomines region, Eastern Cameroon. The study area contains several gold-bearing quartz veins associated with zones of pyritization, muscovite/sericite, iron oxides, and silicification. Principal Component Analysis (PCA), Independent Component Analysis (ICA), and specialized spectral band ratios were used to extract spectral information related to vegetation, iron oxide/hydroxide minerals, Al–OH, Fe-Mg–OH, carbonate group minerals, and silicification using Landsat-8 data at regional scale. Linear Spectral Unmixing (LSU) algorithm was implemented to ASTER VNIR+SWIR bands for detailed discrimination of hematite, jarosite, kaolinite, muscovite, chlorite and epidote at district scale. The Automated Spectral Hourglass (ASH) technique was employed to extract reference spectra directly from the ASTER bands for producing fraction images of end-members using the LSU. A comprehensive field survey was used to verify the remote sensing results. Petrographic study, X-ray diffraction analysis and reflectance spectroscopy indicated the presence of quartz, goethite and sericite, as well as the absorption features of Fe³⁺/Fe²⁺, Al–OH, OH/H2O and SiO₂ in the alteration zones. Several hydrothermal alteration zones of iron oxide/hydroxide, clay, carbonate minerals and silicification zones were identified, which are spatially associated with known mining areas and gold occurrences in the study area. High potential prospects were also delineated, including the Ngoura-Colomines prospects and the newly discovered Yangamo-Ndatanga and Taparé-Tapondo prospects in the southwestern and southeastern parts of the study area. Consequently, satellite-based mineral prospectivity maps at regional and district scales were generated for the study area by implementing the fuzzy logic model to the most informative thematic layers derived from image processing results. The satellite-based prospectivity maps are reliable for exploration of new gold prospective zones in the Ngoura-Colomines goldfield