Controls on development and diversity of Early Archean stromatolites

The ≈3,450-million-year-old Strelley Pool Formation in Western Australia contains a reef-like assembly of laminated sedimentary accretion structures (stromatolites) that have macroscale characteristics suggestive of biological influence. However, direct microscale evidence of biology—namely, organic microbial remains or biosedimentary fabrics—has to date eluded discovery in the extensively-recrystallized rocks. Recently-identified outcrops with relatively good textural preservation record microscale evidence of primary sedimentary processes, including some that indicate probable microbial mat formation. Furthermore, we find relict fabrics and organic layers that covary with stromatolite morphology, linking morphologic diversity to changes in sedimentation, seafloor mineral precipitation, and inferred microbial mat development. Thus, the most direct and compelling signatures of life in the Strelley Pool Formation are those observed at the microscopic scale. By examining spatiotemporal changes in microscale characteristics it is possible not only to recognize the presence of probable microbial mats during stromatolite development, but also to infer aspects of the biological inputs to stromatolite morphogenesis. The persistence of an inferred biological signal through changing environmental circumstances and stromatolite types indicates that benthic microbial populations adapted to shifting environmental conditions in early oceans

The paleobiological record of photosynthesis

Fossil evidence of photosynthesis, documented in Precambrian sediments by microbially laminated stromatolites, cyanobacterial microscopic fossils, and carbon isotopic data consistent with the presence of Rubisco-mediated CO2-fixation, extends from the present to ~3,500 million years ago. Such data, however, do not resolve time of origin of O2-producing photoautotrophy from its anoxygenic, bacterial, evolutionary precursor. Though it is well established that Earth’s ecosystem has been based on autotrophy since its very early stages, the time of origin of oxygenic photosynthesis, more than 2,450 million years ago, has yet to be established

Report of the Terrestrial Bodies Science Working Group. Volume 5: Mars

Present knowledge of the global properties and surface characteraretics of Mars and the composition and dynamics of its atmosphere are reviewed. The objectives of proposed missions, the exploration strategy, and supporting research and technology required are delineated

Physical characteristics of soybean cultivated under the conditions of integrated agrosystems.

Abstract: Integrated crop-livestock-forest (ICLF) systems involve intercropping of various crops to achieve beneficial and synergistic outcomes, enhancing both economic viability and environmental sustainability. Considering the complexity of integrated agrosystems and the economic importance of soybean production in Brazil, we aimed to investigate the effects of two ICLF systems on the physical characteristics and quality of soybeans produced. The treatments comprised plots (two ha) with either single-row (ICLFS) or triple-row (ICLFT), tree configurations intercropped with soybean (maize and forage grass), and control plots (one ha), whose crops were cultivated under full sunlight (CFS). Soybeans were harvested from plants located at 3, 6, 10 and 15 m from tree bands in the north and south faces of the ICLF systems and at random positions in the CFS plots. The moisture content, electrical conductivity of the exudate solution, hue angle and chroma index of grains harvested from ICLFS and ICLFT were similar to those of CFS-grown soybeans. However, the mass of 1000 grains and the bulk density values of ICLF-grown soybeans were significantly higher (P ≤ 0.05) than those of grains harvested from CFS plots. We conclude that the quality of soybean seeds was not negatively affected by the conditions prevailing in the ICLF systems. Moreover, it appears that the forest component contributed positively to the ecosystem by providing a favorable microclimate for the development of soybean grains

In search of phylogenetic congruence between molecular and morphological data in bryozoans with extreme adult skeletal heteromorphy

peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tsab20© Crown Copyright 2015. This document is the author's final accepted/submitted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it

The Kondo Effect in Non-Equilibrium Quantum Dots: Perturbative Renormalization Group

While the properties of the Kondo model in equilibrium are very well understood, much less is known for Kondo systems out of equilibrium. We study the properties of a quantum dot in the Kondo regime, when a large bias voltage V and/or a large magnetic field B is applied. Using the perturbative renormalization group generalized to stationary nonequilibrium situations, we calculate renormalized couplings, keeping their important energy dependence. We show that in a magnetic field the spin occupation of the quantum dot is non-thermal, being controlled by V and B in a complex way to be calculated by solving a quantum Boltzmann equation. We find that the well-known suppression of the Kondo effect at finite V>>T_K (Kondo temperature) is caused by inelastic dephasing processes induced by the current through the dot. We calculate the corresponding decoherence rate, which serves to cut off the RG flow usually well inside the perturbative regime (with possible exceptions). As a consequence, the differential conductance, the local magnetization, the spin relaxation rates and the local spectral function may be calculated for large V,B >> T_K in a controlled way.Comment: 9 pages, invited paper for a special edition of JPSJ "Kondo Effect -- 40 Years after the Discovery", some typos correcte

Épocas de dessecação influenciam na qualidade de grãos e do óleo de soja.

Resumo: A dessecação de lavouras de soja tem sido utilizada, em algumas situações, para acelerar a senescência das plantas e o processo de secagem natural dos grãos, possibilitando escalonar e condicionar a cultura à colheita mecanizada com menor índice de perdas. Por desconhecimento ou na imi nência de períodos climáticos instáveis que impossibilitem a colheita, alguns produtores realizam a dessecação em estádios anteriores ao recomendado. Dessa forma, avaliou-se a influência da aplicação de dessecante em dife rentes estádios de maturação dos grãos de soja na qualidade dos grãos e do óleo. Duas cultivares (BRS 7980 e M8372 IPRO) foram avaliadas quanto à dessecação em cinco estádios fenológicos (R5.5, R6, R7.1 R7.3, R8.1), utilizando-se o dessecante Diquat, na safra 2018/2019. Após a colheita, os grãos foram secos, limpos e classificados. Em seguida, avaliados quanto às propriedades físicas e fisiológicas. A antecipação da dessecação reduziu a massa de mil grãos, aumentou a massa específica aparente e diminuiu a quantidade de óleo nos grãos. A aplicação do herbicida dessecante no está dio recomendado reduziu a deterioração dos grãos no campo. | Abstract: The desiccation of soybean crops has been used to accelerate plant senescence and the natural drying process of grains, allowing for the scaling and conditioning of the crop for mechanical harvesting with lower loss rates. Due to ignorance or the imminent threat of unstable weather periods that may make harvesting impossible, some producers carry out desiccation at earlier stages than recommended. In this way, the influence of desiccant application at different stages of soybean grain maturity on grain and oil quality was evaluated. Two cultivars (BRS 7980 and M8372 IPRO) were evaluated for desiccation at five phenological stages (R5.5, R6, R7.1, R7.3, R8.1) using the desiccant Diquat in the 2018/2019 season. After harvesting, the grains were dried, cleaned, and classified. Subsequently, they were evaluated for physical and physiological properties. The early desiccation reduced the mass of one thousand grains, increased the apparent specific mass, and decreased the amount of oil in the grains. The application of the desiccant herbicide at the recommended stage reduced grain deterioration in the field

Épocas de dessecação nos atributos pós-colheita de grãos de soja.

Resumo: Visando aumentar a janela de plantio da segunda safra, a aplicação de herbicida dessecante na lavoura de soja antes da maturação fisiológica dos grãos tem sido prática comum no médio norte de Mato Grosso, por parte dos produtores. Assim, objetivou-se, por meio deste trabalho, avaliar o efeito da aplicação de dessecante em diferentes estádios fenológicos da lavoura de soja nos aspectos físicos e químicos dos grãos, em Sinop-MT, durante a safra da soja 2018/19. As cultivares BRS 7980 e M 8372 IPRO foram dessecadas em cinco estádios fenológicos distintos (R5.5, R6, R7.1, R7.3, R8.1). Após a colheita, os grãos foram secos, limpos e classificados. Em seguida, determinou-se a massa específica aparente, a massa de mil grãos e os componentes de composição centesimal (fibra bruta, extrato etéreo, proteína, cinzas, carboidrato e água). A antecipação da dessecação reduziu a massa de mil grãos, aumentou a massa específica aparente e diminuiu a quantidade de óleo nos grãos. A aplicação do herbicida dessecante no estádio recomendado reduziu as injúrias causadas por patógenos nos grãos de soja das duas cultivares. | Abstract: In order to increase the planting window of the second crop, some producers have used an application of desiccant herbicide before physiological maturation of soybeans in the middle northern of Mato Grosso. The objective of this work was to evaluate the effect of desiccant application at different stages of maturation of soybean crops, and to evaluate the influence of this operation on physical and chemical aspects of the grains. We used grains from cultivars BRS 7980 and M 8372 IPRO. For each cultivar evaluated, desiccation occurred in five phenological stages (R5.5, R6, R7.1, R7.3, R8.1). After harvesting, the beans were dried, cleaned and classified. The anticipation of desiccation reduced the mass of a thousand grains, increased the apparent specific mass and decreased the amount of oil in the grains. The application of the desiccant herbicide at the recommended stage reduced the deterioration of the grains in the field, caused by pathogens

Tropical air-sea interaction in general circulation models

An intercomparison is undertaken of the tropical behavior of 17 coupled ocean-atmosphere models in which at least one component may be termed a general circulation model (GCM). The aim is to provide a taxonomy—a description and rough classification—of behavior across the ensemble of models, focusing on interannual variability. The temporal behavior of the sea surface temperature (SST) field along the equator is presented for each model, SST being chosen as the primary variable for intercomparison due to its crucial role in mediating the coupling and because it is a sensitive indicator of climate drift. A wide variety of possible types of behavior are noted among the models. Models with substantial interannual tropical variability may be roughly classified into cases with propagating SST anomalies and cases in which the SST anomalies develop in place. A number of the models also exhibit significant drift with respect to SST climatology. However, there is not a clear relationship between climate drift and the presence or absence of interannual oscillations. In several cases, the mode of climate drift within the tropical Pacific appears to involve coupled feedback mechanisms similar to those responsible for El Niño variability. Implications for coupled-model development and for climate prediction on seasonal to interannual time scales are discussed. Overall, the results indicate considerable sensitivity of the tropical coupled ocean-atmosphere system and suggest that the simulation of the warm-pool/cold-tongue configuration in the equatorial Pacific represents a challenging test for climate model parameterizations