58 research outputs found

    Mass Production and Morphology of Marandu Brachiaria Under Different Nitrogen Rates in the Brazilian Savannah

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    Nitrogen is the nutrient that most contributes to increase forage productivity and quality. The objective was to evaluate Marandu brachiaria submitted to nitrogen doses in the Brazilian savannah through the total and green mass production, leaf:stem and brachiaria:weed ratio. Plots were established in a randomized block design, with four replications and four N doses 0, 50, 100 and 150 kg N/ha). After the uniformization cut, the data collect cycles occurred when the canopy reached 30 cm average height. Samples were taken until 15 cm from the ground in an area of 0.25 m2. Fractions were separated according botanical (brachiaria and weeds) and morphological (leaf, stem, dead material and inflorescence) components. The highest value of dry matter production and green mass production occurred at 96 and 72 kg N/ha dose (2,669 kg and 1,946 DM/ha). Above and below this value the mass production decreased . The highest relation green mass:dead material ratio was 4.00 at 150 kg N/ha dose. Marandu was able to control the weeds, and the best performance (4.67) was observed at 78 kg N/ha dose. Forage accumulation rate is the mass production/day and the highest accumulation rate occurred at 50 kg N/ha dose. Marandu had higher leaf:stem ratio with nitrogen dose 107 kg N/ha but above 50 kg/N the mass accumulation rate decrease which means that the fertilization cost is not favorable over up this dose, especially above dose 72 kg N/kg when there green mass production decrease

    Morphogenesis of Marandu Brachiaria Under Different Nitrogen Rates in the Brazilian Savannah

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    Nitrogen fertilization contributes to grass growth and, for this reason, the objective was to evaluate the morphogenic characteristics of Urochloa brizantha cultivar Marandu subjected to different nitrogen rates (0, 50, 100 and 150 kg N.ha-1) in the Brazilian savannah through the variables number of leaves.tiller-1, leaf growth, leaf average size, senescent leaf.tiller-1 number and stem+pseudostem average size. The experiment was established in the Forage and Pastures Sector of Jatai Federal University (UFJ) and, after the soil correction and fertilization, the Marandu grass plots were installed in a randomized blocks experimental design, with four treatments and four replications. When the forage canopy reached the cutting height (30 cm) it was homogenized with pruning shears and four tillers per plot were identified with colored tape and a locating stake. Morphogenesis data was collected every two days, measuring the leaves size and stem+pseudostem size, and leaves were classifying according to their physiological state. Marandu cultivar showed increasing response in leaves number and in leaf growth in nitrogen doses from 50 to 100 kg N.ha-1. The number of senescent leaf.tiller-1 decrease when nitrogen fertilization increase from 0 to 100 kg N.ha-1. Marandu showed a morphogenic response to nitrogen fertilization and up to 100 kg N.ha-1 can be used

    Canopy Changes of Brachiaria Managed Under Continuous Stocking in the Dry-Water Transition

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    Pasture supplementation is an alternative to take advantage of the forage mass deferred in the rainy season and maintain or provide weight gain in periods of rain absence. The objective was to compare the structural characteristics, mass production, density and population dynamics of tillers of Urochloa brizantha cv. ‘Paiaguas’ and U. spp. cv. ‘Convert’ under fixed and continuous stocking with steers supplemented in the trough or on the ground in the water/dry transition period. The experiment was carried out at Jatai Federal University, from March to June, in a completely randomized design and a 2x2 factorial scheme, using six paddocks/treatment. The completely randomized design was adopted and variance analysis was performed with software SAS following the GLM procedure, were compared using repeated-measures. There was a significant interaction between Brachiaria and the method of supplementation for basal, aerial, and total tiller density. Convert had an average of 551 basal and 577 total tiller/m2. Paiaguas grass presented higher tiller density (1,03 vs. 582 tiller/m2) and higher tiller birth rate (12.92 vs. 9.14%) than Convert. No significant difference was observed between brachiarias. The average height of Paiaguas was 62.34 and 50.70 cm for Convert. The average height was 57.83 and on the ground it was 54.90 cm. Supplementation offer method changed Paiaguas canopy. The Convert showed higher leaf and dead mass production but lower weeds despite its smaller tillering

    Canopy Changes of Brachiaria Managed Under Continuous Stocking in the Dry-Water Transition

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    Pasture supplementation is an alternative to take advantage of the forage mass deferred in the rainy season and maintain or provide weight gain in periods of rain absence. The objective was to compare the structural characteristics, mass production, density and population demography of tillers of Urochloa brizantha cv. Paiaguás and Urochloa spp. cv. Convert under fixed and continuous stocking with steers supplemented with pelleted concentrate supplied in the trough or on the ground in the water/dry transition period. The experiment was carried out in the Jatai Federal University, from March to June 2020, in a completely randomized design and a 2 x 2 factorial scheme, using six paddocks/treatment. SAS was used considering repeated measures (RM) at 5% to do variance analysis. There was a significant interaction between Brachiaria and the method of supplementation for basal tiller, aerial and total tiller density. Convert-grass had an average of 551 basal and 577 total tiller/m2. Paiaguas grass presented higher tiller density (1,028 vs. 582 tiller/m2) and higher tiller birth rate (12.92 vs. 9.14%) than Convert. No significant difference was observed between the brachiarias. The average height of Paiaguas-grass was 62.34 cm and 50.70 cm for Convert-grass. The average height was 57.83 cm and on the ground it was 54.90 cm. Supplementation offer method changed Paiaguas canopy. The Convert showed higher leaf and dead mass production but lower weeds despite its smaller tillering

    Electron paramagnetic resonance study of ferroelectric phase transition and dynamic effects in a Mn²⁺ doped [NH₄][Zn(HCOO)₃] hybrid formate framework

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    We present an X- and Q-band continuous wave (CW) and pulse electron paramagnetic resonance (EPR) study of a manganese doped [NH4][Zn(HCOO)3] hybrid framework, which exhibits a ferroelectric structural phase transition at 190 K. The CW EPR spectra obtained at different temperatures exhibit clear changes at the phase transition temperature. This suggests a successful substitution of the Zn2+ ions by the paramagnetic Mn2+ centers, which is further confirmed by the pulse EPR and 1H ENDOR experiments. Spectral simulations of the CW EPR spectra are used to obtain the temperature dependence of the Mn2+ zero-field splitting, which indicates a gradual deformation of the MnO6 octahedra indicating a continuous character of the transition. The determined data allow us to extract the critical exponent of the order parameter (β = 0.12), which suggests a quasi two-dimensional ordering in [NH4][Zn(HCOO)3]. The experimental EPR results are supported by the density functional theory calculations of the zero-field splitting parameters. Relaxation time measurements of the Mn2+ centers indicate that the longitudinal relaxation is mainly driven by the optical phonons, which correspond to the vibrations of the metal–oxygen octahedra. The temperature behavior of the transverse relaxation indicates a dynamic process in the ordered ferroelectric phase

    Dielectric investigations of polycrystalline samarium bismuth ferrite ceramic

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    Results of broadband dielectric investigations of samarium doped bismuth ferrite ceramics are presented in wide temperature range (20–800 K). At temperatures higher than 400 K, the dielectric properties of samarium bismuth ferrite ceramics are governed by Maxwell-Wagner relaxation and electrical conductivity. The DC conductivity increases and activation energy decreases with samarium concentration. In samarium doped bismuth ferrite, the ferroelectric phase transition temperature decreases with samarium concentration and finally no ferroelectric order is observed at x = 0.2. At lower temperatures, the dielectric properties of ferroelectric samarium doped bismuth ferrite are governed by ferroelectric domains dynamics. Ceramics with x = 0.2 exhibit the relaxor-like behaviour

    Brownian motion exhibiting absolute negative mobility

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    We consider a single Brownian particle in a spatially symmetric, periodic system far from thermal equilibrium. This setup can be readily realized experimentally. Upon application of an external static force F, the average particle velocity is negative for F>0 and positive for F<0 (absolute negative mobility).Comment: 4 pages, 3 figures, to be published in PR

    Vilnius Declaration on chronic respiratory diseases : multisectoral care pathways embedding guided self-management, mHealth and air pollution in chronic respiratory diseases

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    Correction: Volume: 10 Issue: 1 Article Number: 49 DOI: 10.1186/s13601-020-00357-4 Published: DEC 17 2020Background: Over 1 billion people suffer from chronic respiratory diseases such as asthma, COPD, rhinitis and rhinosinusitis. They cause an enormous burden and are considered as major non-communicable diseases. Many patients are still uncontrolled and the cost of inaction is unacceptable. A meeting was held in Vilnius, Lithuania (March 23, 2018) under the patronage of the Ministry of Health and several scientific societies to propose multisectoral care pathways embedding guided self-management, mHealth and air pollution in selected chronic respiratory diseases (rhinitis, chronic rhinosinusitis, asthma and COPD). The meeting resulted in the Vilnius Declaration that was developed by the participants of the EU Summit on chronic respiratory diseases under the leadership of Euforea. Conclusion: The Vilnius Declaration represents an important step for the fight against air pollution in chronic respiratory diseases globally and has a clear strategic relevance with regard to the EU Health Strategy as it will bring added value to the existing public health knowledge.Peer reviewe

    ЭЛЕКТРОФИЗИЧЕСКИЕ И ДИЭЛЕКТРИЧЕСКИЕ СВОЙСТВА КОМПОЗИТОВ Pb0,85Zr0,53Ti0,47O3 - Sr2FeMoO6-δ

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    Ferromagnetic-ferroelectric composite materials on the base of Pb0.85Zr0.53Ti0.47O3-Sr2FeMoO6-δ (PZT-SFMO) compound have been prepared by a complex ceramic technology and the citrate-gel synthesis. It was determined that the dielectric permittivity of a sample with a content of PZT of 55 wt. % and SFMO of 45 wt. % increases with temperature due to the rise of electrical conductivity and an influence of the dielectric dispersion caused by the Maxwell-Wagner relaxation. The electrical conductivity of the sample with a content of PZT of 35 wt. % and a content of SFMO of 65 wt. % possesses a clearly expressed frequency dependence, at temperature lower than 600 K, whereas at higher temperatures the electrical conductivity almost does not depends on frequency in the range 20 Hz-1 MHz. This is concerned with a considerable decrease of critical frequency at higher temperatures. At frequencies higher than 100 kHz and temperature lower than 600 K, the electrical conductivity increases by a power law.C помощью комплексной керамической технологии и цитрат-гель синтеза изготовлены ферромагнитно-сегнетоэлектрические композиционные материалы на основе соединения Pb0,85Zr0,53Ti0,47O3-Sr2FeMoO6-δ (ЦТС-SFMO). Установлено, что диэлектрическая проницаемость образца с содержанием ЦТС - 55 вес. % и SFMO - 45 вес. % возрастает с температурой, вследствие роста электропроводности и влияния диэлектрической дисперсии, обусловленной релаксацией Максвелла - Вагнера. Электропроводность образца с содержанием ЦТС - 35 вес. % и SFMO - 65 вес. % имеет явно выраженную зависимость от частоты ниже температуры 600 K, в то время как при более высоких температурах электропроводность почти не зависит от частоты в диапазоне 20 Гц - 1 МГц. Это связано с существенным уменьшением критической частоты при более высоких температурах. При частотах выше 100 кГц и температуре ниже 600 K электропроводность возрастает по степенному закону
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