Substrate suppression of oxidation process in pnictogen monolayers

2D materials present an interesting platform for device designs. However, oxidation can drastically change the system's properties, which need to be accounted for. Through {\it ab initio} calculations, we investigated freestanding and SiC-supported As, Sb, and Bi mono-elemental layers. The oxidation process occurs through an O$_2$ spin-state transition, accounted for within the Landau-Zener transition. Additionally, we have investigated the oxidation barriers and the role of spin-orbit coupling. Our calculations pointed out that the presence of SiC substrate reduces the oxidation time scale compared to a freestanding monolayer. We have extracted the energy barrier transition, compatible with our spin-transition analysis. Besides, spin-orbit coupling is relevant to the oxidation mechanisms and alters time scales. The energy barriers decrease as the pnictogen changes from As to Sb to Bi for the freestanding systems, while for SiC-supported, they increase across the pnictogen family. Our computed energy barriers confirm the enhanced robustness against oxidation for the SiC-supported systems

Nodulation, gas exchanges and production of peanut cultivated with Bradyrhizobium in soils with different textures.

Nitrogen fertilization from biological source is an uncommon practice for peanut growers due to the limited results, mainly in environments with water restriction. In this study, the response of a commercial Bradyrhizobium was evaluated on the nodulation and production of peanuts grown in sandy and medium textured soils. Two experiments using different soils were carried out in the field during the dry season, in Campina Grande, Paraíba State, Brazil. Three peanut genotypes were submitted to the following treatments: 1-no nitrogen fertilization (control), 2- chemical fertilization (ammonium sulfate) and 3- inoculation with Bradyrhizobium [commercial strain BR 1405 (SEMIA 6144)]. A completely randomized 3x3 factorial design was adopted with five repetitions for both experiments. The evaluates variables were: height of the main stem, number of nodes/plant, root length, root dry weight, weight of pods/plant and number of pods/plant. In addition, gas exchanges were estimated using IRGA apparatus. Both genotypes (BRS Havana and L7 Bege) were benefited in relation to production due to an inoculation with SEMIA 6144. No physiological response was verified in genotypes or N-treatments to gas exchange, excepting for the Ci/Ca ratio in the medium textured soil experiment. BRS Havana showed low Ci/Ca ratio in Bradyrhizobium treatment, indicating that SEMIA 6144 improved the plants photosynthetic efficiency

Potencial de populações segregantes de feijão-caupi para biofortificação de grãos.

O feijão-caupi (Vigna unguiculata (L.) Walp.) é uma excelente fonte de proteínas, vitaminas e minerais e representa o alimento básico, principalmente, da população carente do nordeste brasileiro. A biofortificação do feijão-caupi representa uma das estratégias de combate à desnutrição dessas populações, por meio do aumento dos teores de nutrientes nos grãos, via melhoramento genético. Este trabalho objetivou avaliar populações segregantes de feijão-caupi para a biofortificação dos teores de proteína, ferro e zinco nos grãos. Realizaram-se cruzamentos entre os genótipos parentais BRS Xiquexique (P1), IT-98K-205-8 (P2) e IT-97K-1042-3 (P3), incluindo os seus recíprocos (P1 x P2, P2 x P1, P1 x P3 e P3 x P1) e retrocruzamentos das gerações F1 com P1. As gerações F1, resultantes dos cruzamentos e dos retrocruzamentos, foram avançadas para as gerações F2 e F3. Os genótipos parentais e as populações F3 foram avaliados no campo experimental da Embrapa Meio-Norte, em Teresina, PI, em delineamento de blocos casualizados, com quatro repetições. Avaliaram-se os seguintes caracteres: teor de proteína, teor de ferro e teor de zinco. Os caracteres nutricionais apresentam baixo componente genético na expressão do fenótipo, exceto o teor de proteína, em que a seleção fenotípica é mais eficiente. Maior sucesso na biofortificação dos teores de proteína poderá ser obtido por meio da seleção dentro da população F3C4. A população F3RC4 apresenta maior potencial para o desenvolvimento de cultivares biofortificadas para os teores de ferro e zinco nos grãos de feijão-caupi