Caracterização de terras pretas arqueológicas no sul do estado do Amazonas

As Terras Pretas Arqueológicas (TPAs) são unidades de solo que apresentam como características alta fertilidade, coloração escura e presença de fragmentos cerâmicos. Sobre a formação das TPAs, a hipótese mais bem aceita entre os pesquisadores é que essas foram originadas a partir de processos antrópicos provocados pelos homens pré-colombianos. Diante disso, objetivou-se caracterizar TPAs localizadas nos municípios de Apuí e Manicoré, na região sul do Estado do Amazonas. Foram selecionados sete locais de ocorrência de TPAs, sendo abertas trincheiras e os perfis do solo caracterizados morfologicamente. Procedeu-se à coleta de amostras de solo em cada horizonte para as seguintes análises físicas e químicas: composição granulométrica, argila dispersa em água, grau de floculação, densidade do solo, densidade de partículas e porosidade total, pH em água e KCl, Ca2+, Mg2+, K+ e Al3+ trocáveis, P disponível, H+Al e C orgânico, além dos teores dos óxidos do ataque sulfúrico, óxidos livre e formas mal cristalizadas. A textura dos horizontes A antrópicos variaram de franco-arenosa a franco-argilosa. Os fragmentos cerâmicos e material lítico apresentaram-se em quantidades e profundidades semelhantes no horizonte A dos perfis estudados, sugerindo certa similaridade dos fatores antrópicos que promoveram sua formação. Os horizontes antrópicos dos perfis P3, P4 e P7 apresentaram caráter eutrófico e teores altos a muito altos de fósforo disponível, quando comparados aos perfis P1, P2, P5 e P6, evidenciando heterogeneidade das TPAs.

Growth and magnetic properties of multiferroic LaxBi1-xMnO3 thin films

A comparative study of LaxBi1-xMnO3 thin films grown on SrTiO3 substrates is reported. It is shown that these films grow epitaxially in a narrow pressure-temperature range. A detailed structural and compositional characterization of the films is performed within the growth window. The structure and the magnetization of this system are investigated. We find a clear correlation between the magnetization and the unit-cell volume that we ascribe to Bi deficiency and the resultant introduction of a mixed valence on the Mn ions. On these grounds, we show that the reduced magnetization of LaxBi1-xMnO3 thin films compared to the bulk can be explained quantitatively by a simple model, taking into account the deviation from nominal composition and the Goodenough-Kanamori-Anderson rules of magnetic interactions.

Continuous phase transition in a spin-glass model without time-reversal symmetry

We investigate the phase transition in a strongly disordered short-range three-spin interaction model characterized by the absence of time-reversal symmetry in the Hamiltonian. In the mean-field limit the model is well described by the Adam-Gibbs-DiMarzio scenario for the glass transition; however, in the short-range case this picture turns out to be modified. The model presents a finite temperature continuous phase transition characterized by a divergent spin-glass susceptibility and a negative specific-heat exponent. We expect the nature of the transition in this three-spin model to be the same as the transition in the Edwards-Anderson model in a magnetic field, with the advantage that the strong crossover effects present in the latter case are absent.

ASPECTS OF THE SILVOPASTORAL SYSTEM CORRELATED WITH PROPERTIES OF A TYPIC QUARTZIPSAMMENT (ENTISOL) IN MATO GROSSO DO SUL, BRAZIL

In Brazil, grazing mismanagement may lead to soil and pasture degradation. To impede this process, integrated cropping systems such as silvopasture have been an effective alternative, allied with precision agriculture based on soil mapping for site-specific management. In this study, we aimed to define the soil property that best sheds light on the variability of eucalyptus and forage yield. The experiment was conducted in the 2011/12 crop year in Ribas do Rio Pardo, Mato Grosso do Sul State, Brazil. We analyzed linear and spatial correlations between eucalyptus traits and physical properties of a Typic Quartzipsamment at two depths (0.00-0.10 and 0.10-0.20 m). For that purpose, we set up a geostatistical grid for collection at 72 points. Gravimetric moisture in the 0.00-0.10 m layer is an important index of soil physical quality, showing correlation to eucalyptus circumference at breast height (CBH) in a Typic Quartzipsamment. With an increase in resistance to penetration in the soil surface layer, there is an increase in eucalyptus height and in neutral detergent fiber content in the forage crop. From a spatial point of view, the height of eucalyptus and the neutral detergent fiber of forage can be estimated by co-kriging analysis with soil resistance to penetration. Resistance to penetration values above 2.3 MPa indicated higher yielding sites.

Contrasts in Areas of Rubber Tree Clones in Regard to Soil and Biomass Carbon Stocks

ABSTRACT Rubber tree (Hevea brasiliensis) crop may accumulate significant amounts of carbon either in biomass or in the soil. However, a comprehensive understanding of the potential of the C stock among different rubber tree clones is still distant, since clones are typically developed to exhibit other traits, such as better yield and disease tolerance. Thus, the aim of this study was to address differences among different areas planted to rubber clones. We hypothesized that different rubber tree clones, developed to adapt to different environmental and biological constrains, diverge in terms of soil and plant biomass C stocks. Clones were compared in respect to soil C stocks at four soil depths and the total depth (0.00-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40, and 0.00-0.40 m), and in the different compartments of the tree biomass. Five different plantings of rubber clones (FX3864, FDR 5788, PMB 1, MDX 624, and CDC 312) of seven years of age were compared, which were established in a randomized block design in the experimental field in Rio de Janeiro State. No difference was observed among plantings of rubber tree clones in regard to soil C stocks, even considering the total stock from 0.00-0.40 m depth. However, the rubber tree clones were different from each other in terms of total plant C stocks, and this contrast was predominately due to only one component of the total C stock, tree biomass. For biomass C stock, the MDX 624 rubber tree clone was superior to other clones, and the stem was the biomass component which most accounted for total C biomass. The contrast among rubber clones in terms of C stock is mainly due to the biomass C stock; the aboveground (tree biomass) and the belowground (soil) compartments contributed differently to the total C stock, 36.2 and 63.8 %, respectively. Rubber trees did not differ in relation to C stocks in the soil, but the right choice of a rubber clone is a reliable approach for sequestering C from the air in the biomass of trees.

Least Limiting Water Range and Load Bearing Capacity of Soil under Types of Tractor-Trailers for Mechanical Harvesting of Green Sugarcane

ABSTRACT The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. The purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) under the influence of different tractor-trailers used in mechanical sugarcane harvesting. The experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without trailer (T1); harvester with two trailers with a capacity of 10 Mg each (T2); harvester with trailer with a capacity of 20 Mg (T3) and harvester and truck with trailer with a capacity of 20 Mg (10 Mg per compartment) (T4). The least limiting water range and soil bearing capacity were evaluated. The transport equipment to remove the harvested sugarcane from the field (trailer) at harvest decreased the least limiting water range, reducing the structural soil quality. The truck trailer caused the greatest impact on the soil physical properties studied. The soil load bearing capacity was unaffected by the treatments, since the pressure of the harvester (T1) exceeded the pre-consolidation pressure of the soil.

Fluid-rock-strain feedbacks in extensional shear zones

La présence de fluide météorique synchrone à l'activité du détachement (Farmin, 2003 ; Mulch et al., 2007 ; Gébelin et al., 2011), implique que les zones de cisaillement sont des systèmes ouverts avec des cellules de convections à l'échelle crustale et un intense gradient géothermique au sein du détachement (Morrison et Anderson, 1998, Gottardi et al., 2011). De plus, les réactions métamorphiques liées à des infiltrations fluides dans les zones de cisaillement extensionnel peuvent influencer les paramètres rhéologiques du système (White and Knipe, 1978), et impliquer la localisation de la déformation dans la croûte. Dans ce manuscrit, deux zones de cisaillement infiltrées par des fluides météoriques sont étudiées, l'une étant largement quartzitique, et l'autre de nature granitique ; les relations entre déformation, fluides, et roches s'appuient sur des approches structurales, microstructurales, chimiques et isotopiques. L'étude du détachement du Columbia river (WA, USA) met en évidence que la déformation mylonitique se développe en un million d'années. La phase de cisaillement principal s'effectue à 365± 30°C d'après les compositions isotopiques en oxygène du quartz et de la muscovite. Ces minéraux atteignent l'équilibre isotopique lors de leur recristallisation dynamique contemporaine à la déformation. La zone de cisaillement enregistre une baisse de température, remplaçant le mécanisme de glissement par dislocation par celui de dissolution- précipitation dans les derniers stades de l'activité du détachement. La dynamique de circulation fluide bascule d'une circulation pervasive à chenalisée, ce qui engendre localement la rupture des équilibres d'échange isotopiques. La zone de cisaillement de Bitterroot (MT, USA) présente une zone mylonitique de 600m d'épaisseur, progressant des protomylonites aux ultramylonites. L'intensité de la localisation de la déformation se reflète directement sur l'hydratation des feldspaths, réaction métamorphique majeure dite de « rock softening ». Une étude sur roche totale indique des transferts de masse latéraux au sein des mylonites, et d'importantes pertes de volume dans les ultramylonites. La composition isotopique en hydrogène des phyllosilicates met en évidence la présence (1) d'une source magmatique/métamorphique originelle, caractérisée par les granodiorites ayant conservé leur foliation magmatique, jusqu'aux protomylonites, et (2) une source météorique qui tamponne les valeurs des phyllosilicates des fabriques mylonitiques jusqu'aux veines de quartz non-déformées. Les compositions isotopiques en oxygène des minéraux illustrent le tamponnement de la composition du fluide météorique par l'encaissant. Ce phénomène cesse lors du processus de chloritisation de la biotite, puisque les valeurs des chlorites sont extrêmement négatives (-10 per mil). La thermométrie isotopique indique une température d'équilibre isotopique de la granodiorite entre 600-500°C, entre 500-300°C dans les mylonites, et entre 300 et 200°C dans les fabriques cassantes (cataclasites et veines de quartz). Basé sur les résultats issus de ce travail, nous proposons un modèle général d'interactions fluide-roches-déformation dans les zones de détachements infiltrées par des fluides météoriques. Les zones de détachements évoluent rapidement (en quelques millions d'années) au travers de la transition fragile-ductile ; celle-ci étant partiellement contrôlée par l'effet thermique des circulations de fluide météoriques. Les systèmes de détachements sont des lieux où la déformation et les circulations fluides sont couplées ; évoluant rapidement vers une localisation de la déformation, et de ce fait, une exhumation efficace. - The presence of meteoric fluids synchronous with the activity of extensional detachment zones (Famin, 2004; Mulch et al., 2007; Gébelin et al., 2011) implies that extensional systems involve fluid convection at a crustal scale, which results in high geothermal gradients within active detachment zones (Morrison and Anderson, 1998, Gottardi et al., 2011). In addition, the metamorphic reactions related to fluid infiltration in extensional shear zones can influence the rheology of the system (White and Knipe, 1978) and ultimately how strain localizes in the crust. In this thesis, two shear zones that were permeated by meteoric fluids are studied, one quartzite-dominated, and the other of granitic composition; the relations between strain, fluid, and evolving rock composition are addressed using structural, microstructural, and chemical/isotopic measurements. The study of the Columbia River detachment that bounds the Kettle core complex (Washington, USA) demonstrates that the mylonitic fabrics in the 100 m thick quartzite- dominated detachment footwall developed within one million years. The main shearing stage occurred at 365 ± 30°C when oxygen isotopes of quartz and muscovite equilibrated owing to coeval deformation and dynamic recrystallization of these minerals. The detachment shear zone records a decrease in temperature, and dislocation creep during detachment shearing gave way to dissolution-precipitation and fracturing in the later stages of detachment activity. Fluid flow switched from pervasive to channelized, leading to isotopic disequilibrium between different minerals. The Bitterroot shear zone detachment (Montana, USA) developed a 600 m thick mylonite zone, with well-developed transitions from protomylonite to ultramylonite. The localization of deformation relates directly to the intensity of feldspar hydration, a major rock- softening metamorphic reaction. Bulk-rock analyses of the mylonitic series indicate lateral mass transfer in the mylonite (no volume change), and significant volume loss in ultramylonite. The hydrogen isotope composition of phyllosilicates shows (1) the presence of an initial magmatic/metamorphic source characterized by the granodiorite in which a magmatic, and gneissic (protomylonite) foliation developed, and (2) a meteoric source that buffers the values of phyllosilicates in mylonite, ultramylonite, cataclasite, and deformed and undeformed quartz veins. The mineral oxygen isotope compositions were buffered by the host-rock compositions until chloritization of biotite started; the chlorite oxygen isotope values are negative (-10 per mil). Isotope thermometry indicates a temperature of isotopic equilibrium of the granodiorite between 600-500°C, between 500-300°C in the mylonite, and between 300 and 200°C for brittle fabrics (cataclasite and quartz veins). Results from this work suggest a general model for fluid-rock-strain feedbacks in detachment systems that are permeated by meteoric fluids. Phyllosilicates have preserved in their hydrogen isotope values evidence for the interaction between rock and meteoric fluids during mylonite development. Fluid flow generates mass transfer along the tectonic anisotropy, and mylonites do not undergo significant volume change, except locally in ultramylonite zones. Hydration of detachment shear zones attends mechanical grain size reduction and enhances strain softening and localization. Self-exhuming detachment shear zones evolve rapidly (a few million years) through the transition from ductile to brittle, which is partly controlled by the thermal effect of circulating surface fluids. Detachment systems are zones in the crust where strain and fluid flow are coupled; these systems. evolve rapidly toward strain localization and therefore efficient exhumation.

The non-LTR retrotransposons in Ciona intestinalis: new insights into the evolution of chordate genomes

Background: Non-long terminal repeat (non-LTR) retrotransposons have contributed to shaping the structure and function of genomes. In silico and experimental approaches have been used to identify the non-LTR elements of the urochordate Ciona intestinalis. Knowledge of the types and abundance of non-LTR elements in urochordates is a key step in understanding their contribution to the structure and function of vertebrate genomes. Results: Consensus elements phylogenetically related to the I, LINE1, LINE2, LOA and R2 elements of the 14 eukaryotic non-LTR clades are described from C. intestinalis. The ascidian elements showed conservation of both the reverse transcriptase coding sequence and the overall structural organization seen in each clade. The apurinic/apyrimidinic endonuclease and nucleic-acid-binding domains encoded upstream of the reverse transcriptase, and the RNase H and the restriction enzyme-like endonuclease motifs encoded downstream of the reverse transcriptase were identified in the corresponding Ciona families. Conclusions: The genome of C. intestinalis harbors representatives of at least five clades of non-LTR retrotransposons. The copy number per haploid genome of each element is low, less than 100, far below the values reported for vertebrate counterparts but within the range for protostomes. Genomic and sequence analysis shows that the ascidian non-LTR elements are unmethylated and flanked by genomic segments with a gene density lower than average for the genome. The analysis provides valuable data for understanding the evolution of early chordate genomes and enlarges the view on the distribution of the non-LTR retrotransposons in eukaryotes.

Heparin attenuates TNF-alpha induced inflammatory response through a CD11b dependent mechanism

Background In addition to its anticoagulant properties, heparin has anti-inflammatory effects, the molecular and mechanistic bases of which are incompletely defined. AIMS The current studies were designed to test the hypothesis that heparin abrogates the expression or function of leucocyte-endothelial adherence molecules which are fundamental to the acute inflammatory response. Methods The effects of heparin on tumour necrosis factor alpha (TNF-¿) induced leucocyte rolling, adhesion, and migration as well as vascular permeability were assessed in rat mesenteric venules using intravital microscopy. Expression of adhesion molecules was quantitated using a double radiolabelled monoclonal antibody (mAb) binding technique in vivo (P-selectin, intercellular cell adhesion molecule type 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1)) or flow cytometry (CD11a, CD11b, and L-selectin). Ex vivo binding of heparin to neutrophils was assessed by flow cytometry. RESULTS TNF-alpha induced a significant increase in leucocyte rolling, adhesion, and migration, and vascular permeability, coincident with a significant increase in expression of P-selectin, ICAM-1, and VCAM-1. Ex vivo assessment of blood neutrophils showed significant upregulation of CD11a and CD11b and significant downregulation of L-selectin within five hours of TNF-¿ administration. Heparin pretreatment significantly attenuated leucocyte rolling, adhesion, and migration but did not affect expression of cell adhesion molecules or vascular permeability elicited by TNF-¿ administration. Binding of heparin was significantly increased on blood neutrophils obtained five hours after TNF-¿ administration. Preincubation with an anti-CD11b mAb but not with an anti-CD11a or anti-L-selectin antibody significantly diminished heparin binding ex vivo.

RAE-1, a novel PHR binding protein, is required for axon termination and synapse formation in Caenorhabditis elegans.

Previous studies in Caenorhabditis elegans showed that RPM-1 (Regulator of Presynaptic Morphology-1) regulates axon termination and synapse formation. To understand the mechanism of how rpm-1 functions, we have used mass spectrometry to identify RPM-1 binding proteins, and have identified RAE-1 (RNA Export protein-1) as an evolutionarily conserved binding partner. We define a RAE-1 binding region in RPM-1, and show that this binding interaction is conserved and also occurs between Rae1 and the human ortholog of RPM-1 called Pam (protein associated with Myc). rae-1 loss of function causes similar axon and synapse defects, and synergizes genetically with two other RPM-1 binding proteins, GLO-4 and FSN-1. Further, we show that RAE-1 colocalizes with RPM-1 in neurons, and that rae-1 functions downstream of rpm-1. These studies establish a novel postmitotic function for rae-1 in neuronal development.

Uma estrutura de classificação com enfoque na cultura amazônica

Elaboração de uma estrutura de classificação com o objetivo de ajudar a construir um futuro tesauro que terá como universo temático a cultura amazônica paraense. Foram coletados termos culturais da narrativa Chove nos Campos de Cachoeira, de Dalcídio Jurandir. A obra foi lida com o intuito de identificar, analisar, selecionar, registrar em uma ficha terminológica e definir os termos culturais. Após a etapa da definição, foram estabelecidas as relações entre os conceitos, formando-se classes a partir de suas características comuns. Ao todo, 512 termos culturais foram coletados da narrativa, surgindo 912 unidades conceituais (incluindo as classes, as subclasses, os termos equivalentes e os relacionados). Partindo do princípio de que toda informação organizada tem uma expectativa de geração de novo conhecimento, acredita-se que a elaboração desse tesauro será muito útil para a preservação da memória cultural amazônica.

Base de dados de informações jornalísticas sobre a Amazônia: ciência, tecnologia e meio ambiente - BDIJAm: em busca da qualidade

Apresenta a avaliação da qualidade da Base de Dados de Informações Jornalísticas sobre a Amazônia: Ciência, Tecnologia e Meio Ambiente - BDIJAm. O estudo integra o Projeto Temáticas Amazônicas: Dossiês Comentados e Qualidade da Informação sobre Ciência, Tecnologia e Meio Ambiente, do Museu Paraense Emílio Goeldi. Foram aplicados questionários aos usuários para identificação dos pontos positivos e possíveis lacunas do serviço. Como principais resultados foram apontadas a relevância dos temas da Base e a necessidade de se desenvolver ações que visem aperfeiçoar a estrutura de recuperação da informação. Conclui que toda base de dados deve ser continuamente aperfeiçoada e os usuários consideram a BDIJam um instrumento de suma importância para a sociedade como recurso de preservação da memória social da Amazônia.

Mineralização de nitrogênio e enxofre em solos brasileiros sob influência da calagem e fósforo

O presente estudo, desenvolvido em laboratório no período de outubro de 1995 a janeiro de 1996, objetivou avaliar a influência da calagem e fósforo (P) sobre a mineralização de nitrogênio (N) e enxofre (S) em sete solos, com ampla variabilidade nas características químicas e físicas. Os solos (200 g), numa etapa anterior à aplicação de P (KH2PO4 p.a.), foram pré-incubados por sete dias com CaCO3p.a.Aseguir,foramincubadosnovamente,pormais70dias.OsteoresdeN (NO3- + NH4+) e S (SO4(2-)) mineralizados em condições aeróbias foram avaliados a cada catorze dias, e notou-se neles uma dinâmica diferenciada, com o N mineral apresentando maior variação do que o sulfato. As quantidades de N mineralizado não se mostraram dependentes da acidez do solo, porém notou-se uma aceleração na mineralização do N com a calagem do Glei Húmico e do Latossolo Vermelho-Amarelo coletado no Rio de Janeiro. Ao contrário, a mineralização de S no Glei Pouco Húmico e no Latossolo Vermelho-Amarelo coletado no Rio de Janeiro foi influenciada pela correção da acidez do solo, que promoveu maior disponibilidade de sulfato nesses solos. Os teores de N e S mineralizados não foram influenciados pelos níveis de P disponível. A maior prevalência de nitrato e sulfato em alguns dos solos calcariados implica maior cuidado no estabelecimento da época de aplicação de corretivo.