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
Benzene is a ubiquitous environmental pollutant and an important industrial chemical present in both gasoline and motor vehicle emissions. Occupational human exposure to benzene occurs in the petrochemical and petroleum refining industries as well as in gas-station workers, where it can lead to benzene poisoning (BP), but the mechanisms of BP are not completely understood. In Brazil, a significant number of gas-station service workers are employed. The aim of the present study was to evaluate alterations related to BP and metabolic polymorphisms in gas-station service workers exposed to benzene in the city of Rio de Janeiro, Brazil. Occupational exposure was based on clinical findings related to BP, and metabolic polymorphisms in 114 Brazilian gas-station attendants. These workers were divided into No Clinical Findings (NCF) and Clinical Findings (CF) groups. Neutrophil and Mean Corpuscular Volume (MCV) showed a significant difference between the two study groups, and neutrophil has the greatest impact on the alterations suggestive of BP. The clinical findings revealed higher frequencies of symptoms in the CF group, although not all members presented statistical significance. The frequencies of alleles related to risk were higher in the CF group for GSTM1, GSTT1, CYP2E1 7632T > A, but lower for NQO1 and CYP2E1 1053C > T genotypes. Moreover, an association was found between GSTM1 null and alterations related to BP, but we did not observe any effects of other polymorphisms. Variations in benzene metabolizing genes may modify benzene toxicity and should be taken into consideration during risk assessment evaluations.
Recebido em 23/4/09; aceito em 25/11/09; publicado na web em 23/3/10 ASCORBIC ACID INTERFERENCE IN THE DETERMINATION OF REDUCING AND TOTAL SUGARS BY LANE AND EYNON METHOD. Two studies, both set up as completely randomized design, in a 5x5 and 7x5 factorial schemes, evaluated the interference of 5 and 7 ascorbic acid concentrations and 5 glucose or 5 sucrose concentrations, respectively, on the determination of total and reducing sugars by Lane and Eynon method. The ascorbic acid reducing power (AARP) over the Fehling liquor interfered in the results of total and reducing sugars. On average the AARP was equivalent to 74.83 and 69.71% of the reducing power of glucose and of hydrolyzed sucrose, respectively. The ascorbic acid was stable in all study conditions. Keywords: reducing power; vitamin C; Fehling solution. INTRODUÇÃOVários métodos de análise foram desenvolvidos para medir a concentração total e os tipos de carboidratos presentes nos alimentos, sendo que os mais precisos e poderosos são os métodos cromatográ-ficos: a cromatografia em camada delgada (CCD), a cromatografia gasosa (CG) e a cromatografia líquida de alta resolução (CLAE). Os carboidratos podem ser também separados por eletroforese. 1Esses métodos analíticos apesar de mais precisos por serem de custo elevado não estão disponíveis para a maioria dos laboratórios das indús-trias de alimentos, assim como para a maioria dos laboratórios de pesquisa que utilizam os métodos químicos, muitos deles métodos oficiais.Os métodos químicos usados para determinar carboidratos na forma de monossacarídeos e oligossacarídeos são baseados no fato de que muitos desses apresentam poder redutor (em meio alcalino a quente) sobre o cobre, a prata, o ferro e/ou outras substâncias, produzindo complexos coloridos, ou precipitados que podem ser quantificados.A concentração dos carboidratos pode ser determinada por titulação (Lane-Eynon, EDTA e Luff Schoorl), por gravimetria (Musson-Walker, Tolens) ou por espectrofotometria (Somogyi-Nelson, ADNS, Antrona, Fenol-Sulfúrico).2 As sensibilidades são diferentes, as leituras colorimétricas são muito precisas e as titulométricas, relativamente grosseiras -neste caso, o sucesso da análise repousa na prática do analista. 3Os carboidratos não redutores podem ser determinados pelos mesmos métodos de determinação dos açúcares redutores, desde que eles primeiro sejam hidrolisados, enzimática ou quimicamente, para se tornarem redutores.Os métodos químicos clássicos conhecidos (método de Lane e Eynon, de Benedict, complexométrico de EDTA, de Luff-Schoorl, de Musson-Walker, de Somogyi-Nelson) são fundamentados na redução de íons cobre em soluções alcalinas. 1,2O método de Lane-Eynon baseia-se no fato de que os sais cú-pricos, em solução tartárica alcalina (solução de Fehling), podem ser reduzidos a quente por aldoses ou cetoses transformando-se em sais cuprosos vermelhos, que se precipitam, perdendo sua cor azul primitiva, conforme Figura 1. O tartarato, ao unir-se ao cobre, formando um complexo solúvel, impede a formação de hidróxido cúpr...
Mycobacterium tuberculosis complex (MTC) comprises a group of bacteria that have a high degree of genetic similarity. Two species in this group, Mycobacterium tuberculosis and Mycobacterium bovis, are the main cause of human and bovine tuberculosis, respectively. M. bovis has a broader host range that includes humans; thus, the differentiation of mycobacterium is of great importance for epidemiological and public health considerations and to optimize treatment. The current study aimed to evaluate primers and molecular markers described in the literature to differentiate M. bovis and M. tuberculosis by PCR. Primers JB21/22, frequently cited in scientific literature, presented in our study the highest number of errors to identify M. bovis or M. tuberculosis (73%) and primers Mb.400, designed to flank region of difference 4 (RD4), were considered the most efficient (detected all M. bovis tested and did not detect any M. tuberculosis tested). Although also designed to flank RD4, primers Mb.115 misidentified eight samples due to primer design problems. The results showed that RD4 is the ideal region to differentiate M. bovis from other bacteria classified in MTC, but primer design should be considered carefully.
Suid herpesvirus 1 (SuHV-1) is the causative agent of pseudorabies (PR), a disease of great importance due to the huge losses it causes in the swine industry. The aim of this study was to determine a method for genotyping SuHV-1 based on partial sequences of the gene coding for glycoprotein C (gC) and to elucidate the possible reasons for the variability of this region. A total of 109 gCsequences collected from GenBank were divided into five major groups after reconstruction of a phylogenetic tree by Bayesian inference. The analysis showed that a portion of gC (approximately 671 bp) is under selective pressure at various points that coincide with regions of protein disorder. It was also possible to divide SuHV-1 into five genotypes that evolved under different selective pressures. These genotypes are not specific to countries or continents, perhaps due to multiple introduction events related to the importation of swine.
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