51 research outputs found

    Fine-resolution global maps of root biomass carbon colonized by arbuscular and ectomycorrhizal fungi

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    Despite the recognized importance of mycorrhizal associations in ecosystem functioning, the actual abundance patterns of mycorrhizal fungi belowground are still unknown. This information is key for better quantification of mycorrhizal impacts on ecosystem processes and for incorporating mycorrhizal pathways into global biogeochemical models. Here we present the first high-resolution maps of fine root stocks colonized by arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) fungi (MgC ha-1). The maps were assembled by combining multiple open-source databases holding information on root biomass carbon, the proportion of AM and EcM tree biomass, plot-level relative abundance of plant species and intensity of AM and EcM root colonization. We calculated root-associated AM and EcM abundance in 881 spatial units, defined as the combination of ecoregions and land cover types across six continents. The highest AM abundances are observed in the (sub-)tropics, while the highest EcM abundances occur in the taiga regions. These maps serve as a basis for future research where continuous spatial estimates of root mycorrhizal stocks are needed.Environmental Biolog

    Preparation and scale up of extended-release tablets of bromopride

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    Reproducibility of the tablet manufacturing process and control of its pharmaceutics properties depends on the optimization of formulation aspects and process parameters. Computer simulation such as Design of Experiments (DOE) can be used to scale up the production of this formulation, in particular for obtaining sustained-release tablets. Bromopride formulations are marketed in the form of extended-release pellets, which makes the product more expensive and difficult to manufacture. The aim of this study was to formulate new bromopride sustained release formulations as tablets, and to develop mathematical models to standardize the scale up of this formulation, controlling weight and hardness of the tablets during manufacture according to the USP 34th edition. DOE studies were conducted using Minitab(tm) software. Different excipient combinations were evaluated in order to produce bromopride sustained-release matrix tablets. In the scale-up study, data were collected and variations in tableting machine parameters were measured. Data were processed by Minitab(tm) software, generating mathematical equations used for prediction of powder compaction behavior, according to the settings of the tableting machine suitable for scale-up purposes. Bromopride matrix tablets with appropriate characteristics for sustained release were developed. The scale-up of the formulation with the most suitable sustained release profile was established by using mathematical models, indicating that the formulation can be a substitute for the pellets currently marketed

    Susceptibility amplitude ratio for generic competing systems

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    We calculate the susceptibility amplitude ratio near a generic higher character Lifshitz point up to one-loop order. We employ a renormalization group treatment with LL independent scaling transformations associated to the various inequivalent subspaces in the anisotropic case in order to compute the ratio above and below the critical temperature and demonstrate its universality. Furthermore, the isotropic results with only one type of competition axes have also been shown to be universal. We describe how the simpler situations of mm-axial Lifshitz points as well as ordinary (noncompeting) systems can be retrieved from the present framework.Comment: 20 pages, no figure

    Transpiração e crescimento foliar de crisântemo em função da fração de água transpirável no substrato

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    The objective of this work was to evaluate the response of transpiration and leaf growth of chrysanthemum (Dendranthema grandiflorum) cultivars to available water in the substrate, represented by the fraction of transpirable substrate water (FTbSW). The experiments were performed in two periods, in a completely randomized design, with four chrysanthemum cultivars (Cherie White, Bronze Repin, Yoapple Valley, and Calabria), under two substrate water conditions (with or without water stress), with 10 replicates. Plants were grown in a greenhouse, in 2.8-L pots with substrate. FTSbW, transpiration, and leaf growth were measured daily, during the period of water deficit. The average threshold FTSbW, indicating that transpiration and leaf growth began to be affected, was respectively 0.63 and 0.68 for 'Cherie White', 0.60 and 0.69 for 'Bronze Repin', 0.53 and 0.59 for 'Yoapple Valley', and 0.51 and 0.54 for 'Calabria'. Available water decrease in the substrate reduces leaf growth before restricting transpiration. The Cherie White and Bronze Repin cultivars are more tolerant to water deficit by closing the stomata earlier and retaining more water in the substrate than the Yoapple Valley and Calabria cultivars.O objetivo deste trabalho foi avaliar a resposta da transpiração e do crescimento foliar de cultivares de crisântemo (Dendranthema grandiflorum) ao conteúdo de água disponível no substrato, representado pela fração de água transpirável no substrato (FATSb). Os experimentos foram realizados em dois períodos, em delineamento inteiramente casualizado, com quatro cultivares de crisântemo (Cherie White, Bronze Repin, Yoapple Valley e Calabria), em duas condições hídricas (com ou sem deficiência hídrica), com 10 repetições. As plantas foram cultivadas em casa de vegetação, em vasos de 2,8 L preenchidos com substrato. A FATSb, a transpiração e o crescimento foliar foram determinados diariamente durante o período de deficiência hídrica. As FATSb críticas médias, indicativas de que a transpiração e o crescimento foliar começam a ser afetados, foram respectivamente de 0,63 e 0,68 para 'Cherie White', 0,60 e 0,69 para 'Bronze Repin', 0,53 e 0,59 para 'Yoapple Valley', e 0,51 e 0,54 para 'Calabria'. A diminuição da água disponível no substrato provoca a redução do crescimento foliar antes de restringir a transpiração. As cultivares Cherie White e Bronze Repin são mais tolerantes ao deficit hídrico por fechar os estômatos antes e conservar mais a água no substrato do que as cultivares Yoapple Valley e Calabria
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