477 research outputs found

    Phosphate Fertilization and Mycorrhizal Inoculation Increase Corn Leaf and Grain Nutrient Contents

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    The agricultural use of arbuscular mycorrhizal fungi, such as Rhizoglomus intraradices, can increase the efficiency of phosphate fertilization for the benefit of the corn plant and grain nutrition. In this study, a field experiment was conducted in an area of Selvíria/MS, Brazil, in the years 2019 and 2020, to verify the effects of reduced doses of phosphorus combined with the inoculation of corn seed with R. intraradices on corn plant growth and grain nutrient contents. The experiment was laid in a randomized block design in subdivided plots with four repetitions and twenty treatments resulting from combining five doses of P2O5 (0%, 25%, 50%, 75%, and 100% of the recommended dose) with four doses (0, 60, 120, and 180 g ha1) of an inoculant containing R. intraradices. Leaf and kernel macro- and micronutrient contents were evaluated. The foliar P content in 2020 was a function of the interaction between phosphate fertilization and AMF inoculation, with the highest leaf P content observed at the 100% of P2O5 combined with AMF inoculation between 120 and 140 g ha1. In the grains Mg content, an interaction was observed between the two factors in 2020 and the response surface, showing that the highest Mg content was obtained when maximum doses of P2O5 and maximum doses of inoculant were combined. A response surface showed that, in 2020, the highest leaf Zn content occurred when 35–55% P2O5 is applied with no inoculation and when P2O5 is limited to 20–30%, and there is inoculation with doses between 90 and 150 g ha1. Phosphate fertilization increased foliar K (2019) and Mg (2020) contents, with maximum points at doses of 76.57% and 88.80%, respectivelyinfo:eu-repo/semantics/publishedVersio

    Prototype implementation of a smart locker

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    Smart lockers are intelligent storage units that are increasingly being adopted to help solving the last mile problem. This paper focuses on the concept of an individual smart locker that can be installed at the entrance of a residential house. First, the operational principle and advantages of this concept are discussed. Then, the design, development and implementation of a functional prototype is demonstrated. The prototype was submitted to tests and can be used as a proof of concept.info:eu-repo/semantics/publishedVersio

    Montagem De Comunidades: Conceitos, Domínio E Estrutura Teórica

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    Community assembly refers to any ecological process that operates to select species from a regional pool and put them together in local communities. Initially, Diamond (1975) proposed a community assembly model based on rules explaining the checkerboard distribution of co-occurring bird species in New Guinea archipelago. By that time, the assembly rules proposed interspecific competition as the only plausible explanation for the patterns observed. However, the lack of testable predictions, inappropriate statistical analyses and, mainly, the absence of alternative hypotheses have represented an obstacle for the theory development. With the introduction of phylogenetic/functional analyses in community studies, a meaningful increase of published papers on community assembly has been noticed, mainly due to the development of models providing more predictive power to assembly processes. Hence, we decided to elaborate a critical review about the conceptual progress in the community assembly theory. We point out that a) the community assembly theory has enhanced its predictive power when it became to be associated with solid statistics; b) the hypothesis test by null models has been reinforced as a consistent data analysis method applied in many studies; and c) the neutral theory has been used as a satisfactory alternative to the coexistence hypothesis by deterministic niche-based processes. However, the community assembly theory is not fully mature yet but has a high potential of near-future development, mainly through the consolidation of its conceptual base. We hope that our review can help in this development by systematizing the community assembly theory and clarifying some misunderstood and/or so-far poorly applied concepts. © 2016, Universidade Federal do Rio de Janeiro (UFRJ). All rights reserved.20111

    Progress in the determination of the J/ψπJ/\psi-\pi cross section

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    Improving previous calculations, we compute the J/ψπcharmedmesonsJ/\psi \pi\to {charmed mesons} cross section using QCD sum rules. Our sum rules for the J/ψπDˉDJ/\psi \pi\to \bar{D} D^*, DDˉD \bar{D}^*, DˉD{\bar D}^* D^* and DˉD{\bar D} D hadronic matrix elements are constructed by using vaccum-pion correlation functions, and we work up to twist-4 in the soft-pion limit. Our results suggest that, using meson exchange models is perfectly acceptable, provided that they include form factors and that they respect chiral symmetry. After doing a thermal average we get 0.3\sim 0.3 mb at T=150\MeV.Comment: 22 pages, RevTeX4 including 7 figures in ps file

    Charmonium - Pion Cross Section from QCD Sum Rules

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    The J/ψπDˉD,DˉDJ/\psi \pi\to \bar{D} D^*, \bar{D} D, DˉD{\bar D}^* D^* and DˉD{\bar D} D^* cross sections as a function of s\sqrt{s} are evaluated in a QCD sum rule calculation. We study the Borel sum rule for the four point function involving pseudoscalar and vector meson currents, up to dimension four in the operator product expansion. We find that our results are smaller than the J/ψπcharmedmesonsJ/\psi \pi\to {charmed mesons} cross sections obtained with models based on meson exchange, but are close to those obtained with quark exchange models.Comment: revised version accepted for publication in Phys. Lett.

    Desenvolvimento comparado de três cultivares de caupi, Vigna unguiculata (L.) Walp

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    An experiment was carried out to establish the comparative growth of three Vigna unguiculata cultivars throught determination of leaf area, dry matter partition and growth analysis. Leaf area established throught the method of relationship between total dry matter of leaves and dry matter of discs with knowed area, and estimated by the product of length x maximum width of leaf x 1.75did not present differences. Cultivar Epace-1 showed higher leaf area duration in relation to Epace-6 and Epace-8 cowpea cultivars. Vigna unguiculata presented an initial exponential phase of dry matter accumulation and a sygmoid phase post-maturity. Accumulation of biomass in the reproductive part of cowpea 'Epace-1' was later and more effective in relation to Epace-6 and Epace-8 cultivars. Cultivar Epace-1 presented later development in relation to 'Epace.6' and 'Epace-8'. Epace-6 cultivar of cowpea showed higher growth on the second part of the plant life cycle in relation to Epace-8 and Epace-1 cultivars. Vigna unguiculata plants presented higher net assimilation rate and relative growth rate from 30 to 50 days after emergence. Cowpea snowed higher leaf area ratio and leaf weight ratio from 28 to 42 days after emergence.Realizou-se determinação comparada da área foliar, da partição de biomassa e da análise de crescimento em três cultivares de Vigna unguiculata (Epace-1, Epace-6 e Epace-8) mantidos em vasos sob condições naturais. Ométodo de estabelecimento da área foliar baseado na correlação entre o peso da matéria seca foliar com o peso de discos foliares de área conhecida mostrou-se equivalente a estimativa (c.1) 1,75, referente aos folíolos terminais. O cultivar Epace-1 apresentou maior número de folhas, maiores incrementos na área foliar e maior duração de área foliar em relação aos cultivares Epace-6 e Epace-8. Vigna unguiculata mostrou uma fase exponencial inicial no acúmulo de matéria seca e uma tendência sigmoidal após a maturidade. O acúmulo de biomassa na parte reprodutiva do caupi iniciou-se mais tardiamente no cultivar Epace-1, sendo que este cultivar alocou maior proporção de carboidratos no sistema radicular com relação aos cultivares Epace-6 e Epace-8. Verificou-se que o cultivar Epace-1 apresentou-se mais tardio do que os cultivares Epace-6 e Epace-8. O cultivar Epace-6 apresentou um incremento no crescimento na segunda fase do ciclo de desenvolvimento com relação aos cultivares Epace-8 e Epace-1. As plantas de caupi atingiram os valores mais altos de taxa assimilatória líquida e de taxa de crescimento relativo de 30 a 50 dias após a emergência. Vigna unguiculata apresentou incrementos na razão de área foliar e na razão de peso foliar de 28 a 42 dias após a emergência

    Dissociation cross sections of ground-state and excited charmonia with light mesons in the quark model

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    We present numerical results for the dissociation cross sections of ground-state, orbitally- and radially-excited charmonia in collisions with light mesons. Our results are derived using the nonrelativistic quark model, so all parameters are determined by fits to the experimental meson spectrum. Examples of dissociation into both exclusive and inclusive final states are considered. The dissociation cross sections of several C=(+) charmonia may be of considerable importance for the study of heavy ion collisions, since these states are expected to be produced more copiously than the J/psi. The relative importance of the productions of ground-state and orbitally-excited charmed mesons in a pion-charmonium collision is demonstrated through the s\sqrt {s}-dependent charmonium dissociation cross sections.Comment: 9 pages, 8 figure

    In vitro development of primordial follicles after long-term culture of goat ovarian tissue

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    This study aims to investigate the effects of follicle stimulating hormone (FSH) and fibroblast growth factor-2 (FGF-2) on the survival and growth of caprine preantral follicles. Ovarian tissues were cultured for 1, 7, 14, 21 or 28 days in medium supplemented with FSH (FSH-2d or FSH-7d, i.e., with replacement of the culture medium every 2 or 7 days, respectively) or FSH + FGF-2 (replacement of the medium every 2 days). Non-cultured (control) and cultured ovarian fragments were processed for histological and ultrastructural analysis. After 28 days of culture, the media supplemented with FSH-2d was the most effective in maintaining the percentage of normal follicles and in promoting follicular growth. Furthermore, both treatments with FSH increased the percentage of the primary follicles. However, ultrastructural studies did not confirm follicular integrity from 14 days of culture onward. In conclusion, culturing tissue for up to 7 days in medium containing FSH alone or combined with FGF-2 maintains caprine preantral follicle integrity and promotes their growth in vitro

    Density mismatch in thin diblock copolymer films

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    Thin films of diblock copolymer subject to gravitational field are simulated by means of a cell dynamical system model. The difference in density of the two sides of the molecule and the presence of the field causes the formation of lamellar patterns with orientation parallel to the confining walls even when they are neutral. The concentration profile of those films is analyzed in the weak segregation regime and a functional form for the profile is proposed.Comment: 9 pages and 8 figures. Needs EPSF macros. Submitted to PR
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