Pedogeomorphological evolution model of Serra da Canastra, MG

A gibbsita e as formas de ferro em solos tropicais são preferencialmente controladas pela posição na paisagem e variação das condições hídricas ao longo das pedossequências. Normalmente, em escala regional, a gibbsita aumenta com a elevação do terreno e a idade da superfície, enquanto que, na escala local, decresce do topo para a base das vertentes. A razão entre o ferro oxalato e o ferro ditionito (Feo/Fed) em condições oxidantes e bem drenadas tendem a ser baixas ( 0,8 são geralmente observadas em Latossolos. O comportamento destes parâmetros na paisagem é decorrente do processo evolutivo das catenas. Este trabalho tem como objetivo descrever uma pedossequência na Serra da Canastra, caracterizada por uma polaridade inversa da gibbsita e razões de Fed/Fe2O3eFeo/Fed próprias de um ambiente redutor. A pedossequência possui Latossolo no topo e Gleissolo na base. Entre a alta e média vertentes ocorrem solos desenvolvidos in situ, com uma sequência apresentando Latossolo a montante e Cambissolo a jusante. Na baixa vertente, ocorrem solos desenvolvidos sobre rampas de colúvio, mostrando a sequência Latossolo- Gleissolo para jusante. Foram coletadas amostras dos horizontes diagnósticos em 10 trincheiras ao longo de uma pedossequência. As amostras foram submetidas às seguintes análises: ferro extraído com ditionito-citrato-bicarbonato (Fed) e oxalato de amônio (Feo), análise termogravimétrica para quantifi cação direta de gibbsita e caulinita e susceptibilidade magnética. O conjunto de dados foi processado por análise multivariada: Análise de Componentes Principais (ACP) e Análise de Grupos (AG). Observou-se que os solos mostram uma evolução lateral de transformação de Latossolos em Gleissolos, de forma progressiva e descontinuada na paisagem. O limite superior da vertente onde ocorrem depósitos coluvionares é marcado pela variação da susceptibilidade magnética, textura e cor do solo. As análises multivariadas (ACP e AG) e os estudos de campo indicam que a pedossequência é derivada de sucessivos solapamentos provocados por erosão subsuperfi cial e deposição de colúvio, com avanço de ambientes hidromórfi cos nestas porções relativamente rebaixadas da paisagem. _________________________________________________________________________________ ABSTRACTThe gibbsite and iron compounds in tropical soils are controlled by landscape position and variation of hydric conditions along the pedosequences. Typically, in the regional scale the gibbsite ratio decrease with increasing elevation and surface age, while in the local scale the ratio decrease from top to base in a pedosequence. The ratio of oxalate iron and dithionite iron (Feo/Fed) under oxidizing conditions and well-drained tend to be low ( 0.8 are observed in Oxisols, generally. The behavior of these parameters in the landscape is the result of the evolutionary process of catenas. This paper aims to describe a pedosequence in Serra da Canastra, characterized by an opposite polarity of gibbsite and iron forms that indicate a reducing environment. This pedosequence has Oxisol in the top and Gleysol on the base. Samples were collected of the soil diagnostic horizon in 10 trenches. The samples were submitted the following procedures: geochemical analyses (major elements), iron extractable with dithionite-citratebicarbonate (Fed) and ammonium oxalate (Feo), thermogravimetric analysis for gibbsite and kaolinite direct quantifi cation and magnetic susceptibility. The data set was processed by multivariate analysis: Principal Component Analysis and Cluster Analysis. Soil transformation through upstream water saturation occurs gradually and discontinued in the landscape. The upper limit of colluvial deposits is marked by magnetic susceptibility, texture and color variation. Principal Components Analysis and Cluster Analysis show physical, chemical and mineralogical trends in the pedosequence. The analyses indicate that the pedosequence is derived of successive sinks and colluviums and the advancement of these hydromorphic environments to the hollows portions of the landscape

Compósitos de matriz estervinílica reforçados com fibras da Luffa cylindrica modificadas superficialmente.

Atualmente existe uma procura por novos materiais de engenharia que apresentem uma combinação de resistência, baixa densidade, facilidade de processamento e custos reduzidos. Neste contexto, compósitos de matriz polimérica reforçados por fibras naturais têm sido estudados nos últimos anos devido às suas vantagens de caráter ecológicas e econômicas. Todavia, o uso em potencial desta classe de materiais é às vezes limitado pela baixa compatibilidade apresentada pelas fibras naturais hidrofílicas por matrizes poliméricas de elevado caráter hidrofóbico. Para melhorar a adesividade e molhabilidade das fibras naturais por matrizes poliméricas tratamentos superficiais físicos e químicos destas fibras têm sido propostos possibilitando melhorias nas propriedades mecânicas dos materiais compósitos. O presente trabalho tem como objetivo o preparo e a caracterização de um material compósito de matriz termorrígida estervinílica reforçado com as fibras do fruto da Luffa cylindrica natural e após tratamentos de modificação. Nesse estudo foram utilizados os tratamentos de extração em solventes orgânicos, mercerização e esterificação com os dianidridos BTDA e PMDA. A microestrutura das fibras foi analisada através de ensaios padronizados como: determinação do teor de umidade, cinzas, extrativos, lignina, α-celulose e holocelulose. Após extração com solventes orgânicos as fibras foram mercerizadas e esterificadas com os dianidridos. As alterações foram acompanhadas através de: FTIR, DRX, titulação, MEV, EDS, DSC e TGA. Para o preparo dos materiais compósitos foi utilizada uma proporção de 15% de fibras em relação à matriz estervinílica e a variação de densidade dos materiais foi determinada. A moldagem e cura dos corpos de prova para ensaios mecânicos foram realizadas sob temperatura e pressão ambiente. A matriz e os compósitos reforçados com as fibras modificadas foram analisados através de: FTIR, MEV, EDS, DSC, TGA e ensaio de absorção de água. Ensaios mecânicos padronizados como impacto Charpy, ensaio de tração e DMTA foram realizados para avaliar a resistência mecânica. Os resultados mostraram que em todos os casos os materiais compósitos reforçados com as fibras da Luffa apresentaram melhorias nas propriedades mecânicas e térmicas em relação à matriz estervinílica. Somente como exemplo, uma redução na densidade de 46%, aumento na resistência à tração de 50% e tenacidade sob impacto de 350% foram obtidas para o compósito reforçado com as fibras esterificadas com BTDA.Nowadays exist research for new engineering materials that present resistance, low density, easiness processes and reduced costs. In this class are the polymeric composites reinforced by natural fibers that have been studied in the last years due to the ecological and economical character advantages. Though, the use in potential of this class of materials is sometimes limited by the low compatibility presented by the natural fibers by polymeric matrices of high hydrophobic character. To improve the adhesiveness and wettability of the natural fibers for polymeric matrices physical and chemical superficial treatments of these fibers they have been proposed making possible improvement in the mechanical properties of the materials composites. The present work has as objective the preparation and the characterization of a composite material of vinyl ester thermosetting polymeric matrix reinforced with the fibers of the fruit of the Luffa cylindrica before and after modification treatments as: organic solvents extraction, mercerization and esterification with BTDA and PMDA dianhydrides. The microstructure of the fibers was analyzed through standards as determination of the humidity percentage, ashes, extractives, lignin, cellulose and holocellulose. After extraction with organic solvents, the fibers were mercerized and esterificated with the dianhydrides. The alterations were accompanied through: FTIR, XRD, TGA, SEM, EDS, DSC and titulation. For the preparation of the materials composites a proportion of 15% of fibers was used in relation to the vinyl ester matrix and the variation of density of the materials determined. The molding and cure of the composites for mechanical tests were accomplished under temperature and pressure environment. The matrix with aluminum hydroxide and the composites reinforced with the modified fibers were analyzed for: FTIR, SEM, EDS, DSC, TGA and absorption of water test. Standardized mechanical tests as Charpy impact, stress strenght and DMTA were accomplished to evaluate the mechanical resistance. The results showed that in all the cases the materials composites reinforced with the fibers Luffa presented improvements in the mechanical and thermal properties in relation to the vinyl ester matrix. Only as example, a reduction in the density of 46%, increases in the stress strenght of 50% and impact resistance of 350% were obtained for the composite reinforced with the fibers esterificated with BTDA

Dynamic mechanical behavior of vinylester matrix composites reinforced by Luffa cylindrica modified fibers.

Currently, there is a demand for new engineering materials presenting a combination of strength, low density, processing easiness, and reduced costs. In this context, polymer matrix composites reinforced by natural fibers have been studied in recent years due to their ecological and economic advantages. Some fibers are still little explored in literature despite presenting a great potential as reinforcement like Luffa cylindrica. The present work aims at the preparation and characterization of a vinylester thermoset matrix composite material reinforced by fibers of the natural L. cylindrica fruit after modification treatments. In this study, extraction treatments in organic solvents, mercerization, and a quite new esterification with BTDA dianhydrides were used and the results showed that in all cases, the composite materials reinforced by Luffa fibers have showed improvements in mechanical and thermal properties compared to the vinylester matrix. As an example, 50% tensile increase was obtained for the composite reinforced by fibers esterified with benzophenone tetracarboxylic dianhydride when compared with thermoset matrix

MODELO DE EVOLUÇÃO PEDOGEOMORFOLÓGICA DA SERRA DA CANASTRA, MG

<p>A gibbsita e as formas de ferro em solos tropicais são preferencialmente controladas pela posição na paisagem e variação das condições hídricas ao longo das pedossequências. Normalmente, em escala regional, a gibbsita aumenta com a elevação do terreno e a idade da superfície, enquanto que, na escala local, decresce do topo para a base das vertentes. A razão entre o ferro oxalato e o ferro ditionito (Fe_o/Fe_d) em condições oxidantes e bem drenadas tendem a ser baixas (&lt; 0,05), como no caso dos Latossolos. Por outro lado, razões mais elevadas (entre 0,5 e 1) caracterizam ambientes submetidos a condições redutoras, que indicam a dissolução de óxidos de ferro cristalinos e sua precipitação em formas menos estáveis. A razão entre o ferro ditionito e o ferro total (Fe_d/Fe₂O₃) é um indicativo do estágio de intemperismo do solo. Razões de Fe_d/Fe₂O₃&gt; 0,8 são geralmente observadas em Latossolos. O comportamento destes parâmetros na paisagem é decorrente do processo evolutivo das catenas. Este trabalho tem como objetivo descrever uma pedossequência na Serra da Canastra, caracterizada por uma polaridade inversa da gibbsita e razões de Fe_d/Fe₂O₃eFe_o/Fe_d próprias de um ambiente redutor. A pedossequência possui Latossolo no topo e Gleissolo na base. Entre a alta e média vertentes ocorrem solos desenvolvidos <em>in situ</em>, com uma sequência apresentando Latossolo a montante e Cambissolo a jusante. Na baixa vertente, ocorrem solos desenvolvidos sobre rampas de colúvio, mostrando a sequência Latossolo- Gleissolo para jusante. Foram coletadas amostras dos horizontes diagnósticos em 10 trincheiras ao longo de uma pedossequência<strong>. </strong>As amostras foram submetidas às seguintes análises: ferro extraído com ditionito-citrato-bicarbonato (Fe_d) e oxalato de amônio (Fe_o), análise termogravimétrica para quantificação direta de gibbsita e caulinita e susceptibilidade magnética. O conjunto de dados foi processado por análise multivariada: Análise de Componentes Principais (ACP) e Análise de Grupos (AG). Observou-se que os solos mostram uma evolução lateral de transformação de Latossolos em Gleissolos, de forma progressiva e descontinuada na paisagem. O limite superior da vertente onde ocorrem depósitos coluvionares é marcado pela variação da susceptibilidade magnética, textura e cor do solo. As análises multivariadas (ACP e AG) e os estudos de campo indicam que a pedossequência é derivada de sucessivos solapamentos provocados por erosão subsuperficial e deposição de colúvio, com avanço de ambientes hidromórficos nestas porções relativamente rebaixadas da paisagem.</p><p> </p

Landscape genomic conservation assessment of a narrow-endemic and a widespread morning glory from Amazonian savannas

Genotype and sequence data for two morning glories (Convolvulaceae): Ipomoea cavalcantei and Ipomoea maurandioides. For each species we provide genotypes in Variant Call Format and sequences in FASTA format.<div><br><div>The data belongs to the following accepted manuscript:</div><div><br></div><div>Lanes ECM, Pope NS, Alves R, Carvalho NM, Giannini TC, Giulietti AM, Imperatriz-Fonseca VL, Monteiro W, Oliveira GC, Silva AR, Siqueira JO, Souza-Filho PMW, Vasconcelos S, Jaffé R (2018) Landscape genomic conservation assessment of a narrow-endemic and a widespread morning glory from Amazonian savannas. Frontiers in Plant Sciences. doi: 10.3389/fpls.2018.00532</div></div

Image_6_Landscape Genomic Conservation Assessment of a Narrow-Endemic and a Widespread Morning Glory From Amazonian Savannas.PDF

<p>Although genetic diversity ultimately determines the ability of organisms to adapt to environmental changes, conservation assessments like the widely used International Union for Conservation of Nature (IUCN) Red List Criteria do not explicitly consider genetic information. Including a genetic dimension into the IUCN Red List Criteria would greatly enhance conservation efforts, because the demographic parameters traditionally considered are poor predictors of the evolutionary resilience of natural populations to global change. Here we perform the first genomic assessment of genetic diversity, gene flow, and patterns of local adaptation in tropical plant species belonging to different IUCN Red List Categories. Employing RAD-sequencing we identified tens of thousands of single-nucleotide polymorphisms in an endangered narrow-endemic and a least concern widespread morning glory (Convolvulaceae) from Amazonian savannas, a highly threatened and under-protected tropical ecosystem. Our results reveal greater genetic diversity and less spatial genetic structure in the endangered species. Whereas terrain roughness affected gene flow in both species, forested and mining areas were found to hinder gene flow in the endangered plant. Finally we implemented environmental association tests and genome scans for selection, and identified a higher proportion of candidate adaptive loci in the widespread species. These mainly contained genes related to pathogen resistance and physiological adaptations to life in nutrient-limited environments. Our study emphasizes that IUCN Red List Criteria do not always prioritize species with low genetic diversity or whose genetic variation is being affected by habitat loss and fragmentation, and calls for the inclusion of genetic information into conservation assessments. More generally, our study exemplifies how landscape genomic tools can be employed to assess the status, threats and adaptive responses of imperiled biodiversity.</p

Data_Sheet_1_Landscape Genomic Conservation Assessment of a Narrow-Endemic and a Widespread Morning Glory From Amazonian Savannas.PDF

<p>Although genetic diversity ultimately determines the ability of organisms to adapt to environmental changes, conservation assessments like the widely used International Union for Conservation of Nature (IUCN) Red List Criteria do not explicitly consider genetic information. Including a genetic dimension into the IUCN Red List Criteria would greatly enhance conservation efforts, because the demographic parameters traditionally considered are poor predictors of the evolutionary resilience of natural populations to global change. Here we perform the first genomic assessment of genetic diversity, gene flow, and patterns of local adaptation in tropical plant species belonging to different IUCN Red List Categories. Employing RAD-sequencing we identified tens of thousands of single-nucleotide polymorphisms in an endangered narrow-endemic and a least concern widespread morning glory (Convolvulaceae) from Amazonian savannas, a highly threatened and under-protected tropical ecosystem. Our results reveal greater genetic diversity and less spatial genetic structure in the endangered species. Whereas terrain roughness affected gene flow in both species, forested and mining areas were found to hinder gene flow in the endangered plant. Finally we implemented environmental association tests and genome scans for selection, and identified a higher proportion of candidate adaptive loci in the widespread species. These mainly contained genes related to pathogen resistance and physiological adaptations to life in nutrient-limited environments. Our study emphasizes that IUCN Red List Criteria do not always prioritize species with low genetic diversity or whose genetic variation is being affected by habitat loss and fragmentation, and calls for the inclusion of genetic information into conservation assessments. More generally, our study exemplifies how landscape genomic tools can be employed to assess the status, threats and adaptive responses of imperiled biodiversity.</p

Table_4_Landscape Genomic Conservation Assessment of a Narrow-Endemic and a Widespread Morning Glory From Amazonian Savannas.PDF

<p>Although genetic diversity ultimately determines the ability of organisms to adapt to environmental changes, conservation assessments like the widely used International Union for Conservation of Nature (IUCN) Red List Criteria do not explicitly consider genetic information. Including a genetic dimension into the IUCN Red List Criteria would greatly enhance conservation efforts, because the demographic parameters traditionally considered are poor predictors of the evolutionary resilience of natural populations to global change. Here we perform the first genomic assessment of genetic diversity, gene flow, and patterns of local adaptation in tropical plant species belonging to different IUCN Red List Categories. Employing RAD-sequencing we identified tens of thousands of single-nucleotide polymorphisms in an endangered narrow-endemic and a least concern widespread morning glory (Convolvulaceae) from Amazonian savannas, a highly threatened and under-protected tropical ecosystem. Our results reveal greater genetic diversity and less spatial genetic structure in the endangered species. Whereas terrain roughness affected gene flow in both species, forested and mining areas were found to hinder gene flow in the endangered plant. Finally we implemented environmental association tests and genome scans for selection, and identified a higher proportion of candidate adaptive loci in the widespread species. These mainly contained genes related to pathogen resistance and physiological adaptations to life in nutrient-limited environments. Our study emphasizes that IUCN Red List Criteria do not always prioritize species with low genetic diversity or whose genetic variation is being affected by habitat loss and fragmentation, and calls for the inclusion of genetic information into conservation assessments. More generally, our study exemplifies how landscape genomic tools can be employed to assess the status, threats and adaptive responses of imperiled biodiversity.</p

Data_Sheet_2_Landscape Genomic Conservation Assessment of a Narrow-Endemic and a Widespread Morning Glory From Amazonian Savannas.XLSX

<p>Although genetic diversity ultimately determines the ability of organisms to adapt to environmental changes, conservation assessments like the widely used International Union for Conservation of Nature (IUCN) Red List Criteria do not explicitly consider genetic information. Including a genetic dimension into the IUCN Red List Criteria would greatly enhance conservation efforts, because the demographic parameters traditionally considered are poor predictors of the evolutionary resilience of natural populations to global change. Here we perform the first genomic assessment of genetic diversity, gene flow, and patterns of local adaptation in tropical plant species belonging to different IUCN Red List Categories. Employing RAD-sequencing we identified tens of thousands of single-nucleotide polymorphisms in an endangered narrow-endemic and a least concern widespread morning glory (Convolvulaceae) from Amazonian savannas, a highly threatened and under-protected tropical ecosystem. Our results reveal greater genetic diversity and less spatial genetic structure in the endangered species. Whereas terrain roughness affected gene flow in both species, forested and mining areas were found to hinder gene flow in the endangered plant. Finally we implemented environmental association tests and genome scans for selection, and identified a higher proportion of candidate adaptive loci in the widespread species. These mainly contained genes related to pathogen resistance and physiological adaptations to life in nutrient-limited environments. Our study emphasizes that IUCN Red List Criteria do not always prioritize species with low genetic diversity or whose genetic variation is being affected by habitat loss and fragmentation, and calls for the inclusion of genetic information into conservation assessments. More generally, our study exemplifies how landscape genomic tools can be employed to assess the status, threats and adaptive responses of imperiled biodiversity.</p