Estudos sobre a nutriçao mineral do arroz: XXVII . Fatores que influenciam a absorção radicular do fósforo pela variedade IAC-164

Within the range of 15 to 240 minutes it was found that absorption increased in a linear fashion.By varying the external concentration of H2PO-4 from 10-7M to 10-2 M a dual pattern uptake was observed: a high affinity macnamism with a Km= 6.17 x 10-6M and a second one with low affinity (Km= 1.64 x 10-2M) . Absorption was raised when the external concentration of Mg ions varied from 10-6 to 10-4When supplied in the range of 10-6 to 10-2M the chloride salis of K and Ca rediced the absorption, the effect being traced to the CI ion. Zincsulfate (10-8to 10-4M) had no effect on phosphate absorption.Na faixa de 15 a 240 minutos a absorção do fósforo marcado com P32 é crescente e linear. A variação na concentração externa de H2PO4 mostrou existirem duas isotermas, uma operando em baixas concentrações (Km = 6,17x10-6M) e outra correspondente a altas concentrações (Km = 1,64x10-2M). Oíon magnésio aumenta a absorção e o Cl- causa diminuição quando fornecido na concentração de 10-2m.SO4-2e Zn+2 não mostraram efeito

Will ultrathin CIGS solar cells overtake the champion thin-film cells? Updated SCAPS baseline models reveal main differences between ultrathin and standard CIGS

Cu(In,Ga)Se2 (CIGS) solar cells are amongst the best performing thin-film technologies, with the latest performance gains being mainly due to recent years improvements obtained with post-deposition treatments (PDT). Moreover, thinning of the absorber layer down to sub-micrometre values (ultrathin absorbers) is of extreme importance for CIGS to be even more cost-effective and sustainable. However, electrical and optical limitations, such as rear interface recombination and insufficient light absorption, prevent the widespread implementation of ultrathin CIGS devices. The recent electrical CIGS simulation baseline models have failed to keep up with the experimental developments. Here an updated and experimentally based baseline model for electrical simulations in the Solar Cell Capacitor Simulator (SCAPS) software is presented and discussed with the incorporation of the PDT effects and increased optical accuracy with the support from Finite-Difference Time-Domain (FDTD) simulation results. Furthermore, a champion solar cell with an equivalent architecture validates the developed thin-film model. The baseline model is also applied to ultrathin CIGS solar cell devices, validated with the ultrathin champion cell. Ultimately, these ultrathin models pave the way for an ultrathin baseline model. Simulations results reveal that addressing these absorbers' inherent limitations makes it possible to achieve an ultrathin solar cell with at least 21.0% power conversion efficiency, with open-circuit voltage values even higher than the recent thin-film champion cells.This work was supported by the Fundação para a Ciência e Tecno-logia (FCT) grant numbers DFA/BD/7073/2020, DFA/BD/4564/2020, SFRH/BD/146776/2019, IF/00133/2015, UIDB/50025/2020, UIDP/50025/2020, UIDB/04730/2020, and UIDP/04730/2020. The authors want to acknowledge the funding from the project NovaCell (PTDC/ CTM-CTM/28075/2017). The authors also acknowledge the financial support of the project Baterias 2030, with the reference POCI-01-0247-FEDER-046109, co-funded by Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDFinfo:eu-repo/semantics/submittedVersio

(Non)commutative isotropization in Bianchi I with Barotropic perfect fluid and Λ\Lambda Cosmological

We present the classical solutions to the Einstein field equations derived using the WKB-like and Hamilton procedures. The investigation is carried out in the commutative and noncommutative scenario for the Bianchi type I cosmological model coupled to barotropic perfect fluid and $\lambda$ Cosmological for two different gauges. Noncommutativity is achieved by modifying the symplectic structure considering that all minisuperspace variables $\rm q^i$ does not commute and by a deformation between all the minisuperspace variables. In the gauge N=1, it is possible to obtain that the anisotropic parameter $\rm \beta_{\pm nc}$ tend to a constant curvature for large period of time considering different values in the noncommutative parameters $\theta$ and cosmological term. However, this behavior give the idea that is necessary introduce other class of matter in the models, for to have a real isotropization in the model, such as dark energy or dark matter.Comment: 15 pages, 1 figur

Embryonic dormancy in seeds of Bactris gasipaes Kunth (peach-palm)

Bactris gasipaes is a domesticated palm whose fruits are of great importance for the Amazonian people and whose heart of palm is also receiving economic interest in other brazilian and Latin America regions. The aim of this study was verify embryonic dormancy and its correlation with first cataphyll emergence in B. gasipaes seeds collected from four plants at Manaus city and four others at Coari city, both in the Amazonas state, Brazil. After extraction and cleaning, some of the seeds (4 replications of 25 per plant) were sown in a seedbed with a sawdust and sand mixture as substrate, and embryos (4 replications of 10 per plant), after extraction, were inoculated into half strength Murashige and Skoog cultures. Were used 100 seeds and 40 embryo per treatment. Whole seed and embryo germination varied between the different source plants and locations, with the greatest difference observed for the emergence of first cataphyll from seeds in the seedbed. For the most part of variables, results of seed and embryo were positively associated, namely, as one went up the other also, and vice versa. These results suggesting that, at least in part, seed dormancy in Bactris gasipaes is associated with embryonic dormancy. © 2017, Associacao Brasileira de Tecnologia de Sementes. All rights reserved