381 research outputs found
Yield and morphology of Nopalea cochenillifera under N fertilization and biological inoculation
Received: August 15th, 2023 ; Accepted: October 30th, 2023 ; Published: November 9th, 2023 ;
Correspondence: [email protected]; [email protected] objective was to evaluate the effect of inoculation with Azospirillum brasilense
and levels of nitrogen fertilization on the productive aspects of the spineless cactus (Nopalea
cochenillifera). The experiment was carried in Ribeirão do Largo, Southwest region of the state
of Bahia, from April 2019 to April 2020. The experiment was carried out in a 2×4 factorial, in a
randomized block design with eight treatments and four replications. The treatments consisted of
the absence or inoculation with Azospirillum brasilense and nitrogen fertilization levels 0, 50,
100 and 150 kg–
¹ of N ha–¹
. There was a positive effect for the use of the bacteria on cladode area
index, height, number of secondary, tertiary and total cladodes, total weight for cladodes of all
orders and also for final weight per ha–¹
. There was a significant effect of the use of the inoculant
for the levels of total soluble sugars and starch, where there was a decrease in the values for the
treatments submitted to the use of the bacteria. There was a quadratic effect for the weight of the
tertiary cladodes, number of tertiary cladodes and total of spineless cactus when submitted to
nitrogen fertilization levels. There was a linear test for cladodes area index when nitrogen
fertilization was used. The use of Azospirillum brasilense is positive for the cultivation of
spineless cactus, improving development and increasing crop productivity
Carbohydrate and protein metabolism of marandu grass affected by nitrogen fertilisation and number of cuts
Received: June 18th, 2023 ; Accepted: September 30th, 2023 ; Published: October 23rd, 2023 ; Correspondence: [email protected] the metabolism of tropical grasses in response to management practises
imposed in pastoral environments allows for improvements in the management and use of mineral
fertilisers. This study aimed to quantify metabolite content in different plant parts of Marandu
grass (Urochloa brizantha), with a specific focus on the influence of nitrogen fertilisation and its
effects following successive cuts. The treatments corresponded to four nitrogen (N) rates
(0, 75, 150, and 225 kg N ha-1
) and the number of cuts (one, two and three cuts). The plants were
fractionated into leaves, stems, and roots to assess the content of water-soluble carbohydrates
(WSC), starch, albumin, globulin, prolamin, and glutelin content. N fertilisation influenced the
WSC and starch content in different parts of the plant, varying according to the cuts made. In the
leaves and roots, fertilisation reduced the content of WSC and starch with one cut, as these were
utilised as energy sources for assimilating the excess nitrogen in the soil. There was an increase
in the concentration of all protein groups with nitrogen fertilisation in all parts of the plant with
one cut. In plants cut two and three times, N fertilisation led to specific increases and decreases
in different parts of the plants as an adaptive strategy for allocating resources as the number of
cuts increased. Our results broaden our understanding of carbohydrate and protein metabolism in
tropical grasses, thereby providing subsidies for the rational use of nitrogen fertilisers
Development of poly(l-Lactic Acid)-based bending actuators
This work reports on the development of bending actuators based on poly(l-lactic acid) (PLLA)/ionic liquid (IL) blends, through the incorporation of 40% wt. of the 1-ethyl-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) IL. The films, obtained by solvent casting at room temperature and 50 °C, were subjected to several post-thermal treatments at 70, 90, 120 and 140 °C, in order to modify the crystallinity of the films. The influence of the drying temperature and of [Emim][TFSI] blending on the morphological, structural, mechanical and electrical properties of the composite materials were studied. The IL induced the formation of a porous surface independently of the processing conditions. Moreover, the [Emim][TFSI] dopant and the post-thermal treatments at 70 °C promoted an increase of the degree of crystallinity of the samples. No significant changes were observed in the degree of crystallinity and Young Modulus for samples with thermal treatment between 70 and 140 °C. The viability of the developed high ionic conductive blends for applications as soft actuators was evaluated. A maximum displacement of 1.7 mm was achieved with the PLLA/[Emim][TFSI] composite prepared at 50 °C and thermally treated at 140 °C, for an applied voltage of 10 Vpp, at a frequency of 100 mHz. This work highlights interesting avenues for the use of PLLA in the field of actuators.The authors thank the FCT—Fundação para a Ciência e Tecnologia—for financial support under the
Strategic Funding UID/FIS/04650/2020, and PEST-C/QUI/UIO686/2019, the Associated Laboratory Research
Unit for Green Chemistry, Technologies and Clean Processes, LAQV (financed by national funds from
FCT/MEC, UID/QUI/50006/2020 and ERDF under the PT2020, POCI-01-0145-FEDER-007265) and projects PTDC/BTM-MAT/28237/2017 and PTDC/EMD-EMD/28159/2017. DMC and LCF also thank the grants
SFRH/BPD/121526/2016 and SFRH/BD/145345/2019, respectively
Striped antiferromagnetic order and electronic properties of stoichiometric LiFeAs from first-principles calculations
We investigate the structural, electronic, and magnetic properties of
stoichiometric LiFeAs by using state-of-the-arts first-principles method. We
find the magnetic ground-state by comparing the total energies among all the
possible magnetic orders. Our calculated internal positions of Li and As are in
good agreement with experiment. Our results show that stoichiometric LiFeAs has
almost the same striped antiferromagnetic spin order as other FeAs-based parent
compounds and tetragonal FeSe do, and the experimental fact that no magnetic
phase transition has been observed at finite temperature is attributed to the
tiny inter-layer spin coupling
Polarized x-ray absorption spectra of CuGeO3 at the Cu and Ge K edges
Polarized x-ray absorption near edge structure (XANES) spectra at both the Cu
and the Ge K-edges of CuGeO3 are measured and calculated relying on the
real-space multiple-scattering formalism within a one-electron approach. The
polarization components are resolved not only in the unit cell coordinate
system but also in a local frame attached to the nearest neighborhood of the
photoabsorbing Cu atom. In that way, features which resist a particular
theoretical description can be identified. We have found that it is the
out-of-CuO4-plane p_{z'} component which defies the one-electron calculation
based on the muffin-tin potential. For the Ge K-edge XANES, the agreement
between the theory and the experiment appears to be better for those
polarization components which probe more compact local surroundings than for
those which probe regions with lower atomic density. Paper published in Phys.
Rev. B 66, 155119 (2002) and available on-line at
http://link.aps.org/abstract/PRB/v66/e155119.Comment: 15 pages, 6 figures. Published in Physical Review B, abstract
available on-line at http://link.aps.org/abstract/PRB/e15511
In Situ Study of Hydrogen Permeable Electrodes for Electrolytic Ammonia Synthesis Using Near Ambient Pressure XPS
Hydrogen permeable electrodes can be utilized for electrolytic ammonia synthesis from dinitrogen, water, and renewable electricity under ambient conditions, providing a promising route toward sustainable ammonia. The understanding of the interactions of adsorbing N and permeating H at the catalytic interface is a critical step toward the optimization of this NH3 synthesis process. In this study, we conducted a unique in situ near ambient pressure X ray photoelectron spectroscopy experiment to investigate the solid gas interface of a Ni hydrogen permeable electrode under conditions relevant for ammonia synthesis. Here, we show that the formation of a Ni oxide surface layer blocks the chemisorption of gaseous dinitrogen. However, the Ni 2p and O 1s XPS spectra reveal that electrochemically driven permeating atomic hydrogen effectively reduces the Ni surface at ambient temperature, while H2 does not. Nitrogen gas chemisorbs on the generated metallic sites, followed by hydrogenation via permeating H, as adsorbed N and NH3 are found on the Ni surface. Our findings suggest that the first hydrogenation step to NH and the NH3 desorption might be limiting under the operating conditions. The study was then extended to Fe and Ru surfaces. The formation of surface oxide and nitride species on iron blocks the H permeation and prevents the reaction to advance; while on ruthenium, the stronger Ru N bond might favor the recombination of permeating hydrogen to H2 over the hydrogenation of adsorbed nitrogen. This work provides insightful results to aid the rational design of efficient electrolytic NH3 synthesis processes based on but not limited to hydrogen permeable electrode
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
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