ABSTRACT Salt stress affects the production of watermelon (Citrullus lanatus) seedlings. However, substrates with alternative materials in their composition can mitigate the harmful effects on the formation of watermelon seedlings. Thus, the objective of the present study was to evaluate the emergence and production of watermelon seedlings grown in different substrates under salt stress. The research was conducted in an agricultural greenhouse belonging to the Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Redenção, Ceará, Brazil. The experimental design used was completely randomized in a split-plot scheme. The plots were five levels of electrical conductivity of irrigation water (ECw: 0.5, 1.5, 2.5, 3.5, and 4.5 dS m-1) and the subplots consisted of two formulations of substrates (SB1: sandy soil + sand + bovine manure; and SB2: sandy soil + sand + biochar; both in a 1:1:1 proportion on volume basis), with five repetitions of 25 seeds. The increase in the electrical conductivity of irrigation water from 1.5 dS m-1 reduces the percentage, speed index, and mean speed of emergence and increases the mean time of emergence of the watermelon crop. Substrate formulated with biochar reduces the time and increases the emergence indexes, besides enabling higher growth and biomass accumulation of watermelon seedlings. Salt stress reduces the growth, biomass, and quality of watermelon seedlings, but with less intensity with the addition of biochar.

RESUMO O estresse salino afeta a produção de mudas de melancia (Citrullus lanatus). Porém, substratos com materiais alternativos na sua composição podem mitigar os efeitos deletérios na formação de mudas de melancia. Dessa forma, objetivou-se avaliar no presente estudo a emergência e a produção de mudas de melancia cultivada em diferentes substratos sob estresse salino. A pesquisa foi desenvolvida em estufa agrícola pertencente à Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Redenção, Ceará, Brasil. O delineamento experimental adotado foi inteiramente casualizado em esquema de parcelas subdivididas. As parcelas corresponderam à cinco níveis de condutividade elétrica da água de irrigação (CEa: 0,5, 1,5, 2,5, 3,5 e 4,5 dS m-1) e as subparcelas à duas formulações de substratos (SB1: areia + arisco + esterco bovino; e SB2: areia + arisco + biochar; ambos com proporção 1:1:1 base de volume), com cinco repetições de 25 sementes. A elevação da condutividade elétrica da água a partir de 1,5 dS m-1 reduz os índices de emergência, e aumenta o tempo médio de emergência da cultura da melancia. Substrato formulado com biochar favorece os índices de emergência, além de possibilitar maior taxa de crescimento e desenvolvimento da biomassa de plântulas de melancia. O estresse salino reduz o desenvolvimento e a qualidade de plântulas de melancia, porém com menor intensidade com adição de biocarvão.

Considering the relevance of natural products to the development of new drugs, this study focuses on the species Sida rhombifolia (L.), Malvaceae, widely used as a traditional remedy in several countries. The species is used to treat several diseases such as fevers, skin diseases, stomach pain, diarrhea, gum infection, conjunctivitis, urinary infections and inflammation. Many researchers around the word have investigated its pharmacological potential, and many uses have been confirmed. In spite of that, the phytochemical composition of its extracts is still poorly investigated. This research aims to make advances on the understanding of the constituents of S. rhombifolia identifying its alkaloidal compounds using ultra-high performance liquid chromatography coupled to mass spectrometry (UPLC-QTOF-MS/MS). By analyzing its alkaloidal fraction, it was possible to identify: 11-cryptolepine carboxylic acid (1), cryptolepine (2), quindoline (3), 11 methoxyquidoline (4), quindolinone (5), cryptolepinone (6), and 11-quindoline methyl ester (7). The alkaloids 1 and 7 are being reported for the first time from Sida genus. Based on the antimicrobial potential of cryptolepinone-type alkaloids, we prepared by semi-synthesis two cryptolepinone derivatives: 10-methylcryptolepinone (8) and the unreported compound 10-ethylcryptolepinone (9). Both derivatives were tested against fungal and bacterial strains and 10-methylcryptolepinone (8) showed strong activity against Cryptococcus neoformans, Candida albicans, Candida tropicalis, Aspergillus fumigatus and Aspergillus flavus.

Abstract For oxide semiconductors for application in dye-sensitized solar cells (DSSCs), titanium dioxide conjugated with zinc oxide thin films was synthesized and characterized. The UV (ultraviolet) spectrum characterization showed a peak of absorbance at around 355 nm, with a band gap of 3.25 eV and reflectance around 85%. Such characteristics allowed the fabrication of DSSCs with N719 dye, under simulated light of 100 mW/cm2. The highest efficiency of 1.17% was at 5% titanium dioxide and 4 h of dye immersion.

RESUMO A salinidade da água de irrigação pode causar sérios problemas na produção agrícola, enquanto as fontes de fertilizantes orgânicos potencialmente mitigam o estresse salino. Assim, este trabalho teve como objetivo avaliar a produtividade da cultura do milho sob irrigação com água salina e adubação orgânica. O estudo foi conduzido em campo de agosto a novembro de 2020 na fazenda experimental da Universidade da Integração Internacional da Lusofonia Afro-Brasileira (UNILAB), Redenção-CE. Utilizou-se o delineamento em blocos casualizados, em parcelas subdivididas, em que as parcelas consistiram em dois níveis de salinidade da água de irrigação (0,8 e 3,0 dS m-1). Nas subparcelas foram aplicadas quatro combinações de fontes de adubo orgânico, compostas por 10 plantas cada, com quatro repetições: C1, esterco bovino + biofertilizante de aves + biofertilizante de cabra; C2, esterco bovino + biofertilizante caprino; C3, esterco bovino + biofertilizante de aves; e C4, tratamento controle. A combinação de fontes de fertilizantes orgânicos não influenciou o acúmulo de assimilados e a produtividade das lavouras de milho sob a salinidade da água de irrigação de 3,0 dS m-1, exceto C3, que atenuou o efeito salino.

ABSTRACT Irrigation water salinity can cause serious problems in crop production, while organic fertilizer sources potentially mitigate saline stress. Thus, this study aimed to evaluate the productivity of maize crops under irrigation with saline water and organic fertilization. The study was conducted in the field from August to November 2020 at the experimental farm of the Universidade da Integração Internacional da Lusofonia Afro-Brasileira (UNILAB), Redenção-CE. A randomized block design was used, in subdivided plots, in which the plots consisted of two levels of irrigation water salinity (0.8 and 3.0 dS m-1). Four combinations of organic fertilizer sources were applied in the subplots, composed of 10 plants each, with four replications: C1, cattle manure + poultry biofertilizer + goat biofertilizer; C2, cattle manure + goat biofertilizer; C3, cattle manure + poultry biofertilizer; and C4, control treatment. The combination of organic fertilizer sources did not influence the accumulation of assimilates and productivity of maize crops under the irrigation water salinity of 3.0 dS m-1, except for C3, which attenuated the saline effect.

RESUMO A cultura do amendoim apresenta grande interesse econômico, em decorrência de suas sementes, constituírem importante fonte de proteína vegetal e de óleo comestível. O objetivo do presente trabalho foi avaliar a fisiologia e crescimento da cultura do amendoim submetido a estresse salino e hídrico. O experimento foi conduzido em Auroras, Redenção, Ceará, Brasil. O delineamento experimental foi inteiramente casualizado em parcelas subdivididas, cujas parcelas referem-se aos níveis de condutividade elétrica da água de irrigação - CEa (1,0; 2,0; 3,0; 4,0 e 5,0 dS m-1) e as subparcelas aos regimes hídricos de 50 e 100% da evapotranspiração da cultura. O estresse salino afeta negativamente a altura de planta, número de folhas e massa seca da parte aérea, índices relativos de clorofila, transpiração e a temperatura foliar da cultura do amendoim. O regime hídrico de 100% da ETc proporcionou maiores desempenhos para as variáveis diâmetro do caule, número de folhas e massa seca da parte aérea da cultura do amendoim.

ABSTRACT Peanut crops are of great economic interest because their seeds are used as an important source of vegetable protein and edible oil. The objective of this study was to evaluate the physiological indices and growth of peanut crops subjected to saline and water stress. The experiment was conducted in Auroras, Redenção, Ceará, Brazil using a completely randomized split plot statistical design. The plots were composed of irrigation water treatments with varying levels of electrical conductivity - ECw (1.0, 2.0, 3.0, 4.0 and 5.0 dS m-1), while the subplots were formed by the water regimes of 50% and 100% crop evapotranspiration. Plant height, leaf number, shoot dry matter, relative chlorophyll level, transpiration, and leaf temperature were affected by salt stress. The water regime of 100% ETc provided better performance for the variables stem diameter, leaf number, and shoot dry mass of peanuts.

Abstract Semiconductors, such as zinc oxide (ZnO), are used in different scientific fields, including energy. This study applied ZnO thin films on a photovoltaic cell, specifically a dye-sensitized solar cell (DSSC). ZnO was used in solar cells due to its characteristics such as electronic mobility. Electrophoretic deposition (EPD) is an efficient method to deposit thin films since it can be done at room temperature and its parameters can be easily controlled. ZnO thin films were deposited on fluorine-doped tin oxide (FTO) glass, changing the tension parameter, and used in a DSSC, with different dye immersion times, between 7 and 24 h, to observe time effects on cell efficiency. For lower tension, 30 and 40 V, 7 h improved the cell efficiency, and at 50 V, 24 h favored the current density and efficiency. The highest efficiency was for the photoanode EPD deposited at 50 V, for 24 h dye immersion, at about 2.68%, and photocurrent of 13.55 mA/cm2.

Abstract Spiny lobsters (Family Palinuridae) are a popular seafood in Brazil. We characterize the fishing activity and analyze the population of lobster species captured in the coast of the state of Rio Grande do Norte, Northeast Brazil. We monitored the landings of lobster fishermen at the start of the fishing season, from May 24 to November 21, in 2010, at Pirangi beach, the main landing point in the metropolitan area of Natal. The lobster fisherman in the region use small vessels and a compressor to dive in artificial reefs known as marambaias. The artisanal fishermen are engaged in several illegal practices and revealed a greater capture of lobsters categorized as small-sized for the market (11-13.95cm tail length). The capture area led to different fishing pressures for each species. For P. laevicauda, fishing pressure occurred for all size classes, while for P. meripurpuratus, pressure occurred partially, only for a few population cohorts. On regional scale, fishing involved a demand-supply trade balance centered on the size of capture vs. abundance, regardless of the natural interespecific differences on body size and the preferential distribution area. Our results provide key information for future decision making involving the fishing of spiny lobster.

RESUMO Objetivou-se avaliar o desempenho de três cultivares de arroz sob salinidade da água de irrigação. O experimento foi conduzido a pleno sol na Fazenda Experimental da Unilab, Redenção, Ceará, em janeiro de 2016. O delineamento experimental foi inteiramente casualizado (DIC), com tratamentos arranjados em esquema fatorial, 5 x 3 [(condutividade elétrica da água de irrigação (CEa: 0,5; 1,0; 2,0; 3,0 e 4,0 dS m-1) aplicadas em três cultivares de arroz (C1- Ligeirinho; C2 - Casado e C3 - Meruinho)], totalizando 15 tratamentos, com 4 repetições de 30 sementes por cultivar. Após 21 dias, foram avaliadas as seguintes variáveis: porcentagem de emergência (PE), índice de velocidade de emergência (IVE), tempo médio de emergência (TME), velocidade média de emergência (VME), massa seca da parte aérea (MSPA), massa seca da raiz (MSR) e massa seca total (MST). A cultivar Ligeirinho possui maior tolerância ao estresse salino quanto à porcentagem de emergência, índice de velocidade de emergência e velocidade média de emergência. A cultivar Casado apresentou maior tolerância ao estresse salino para massa seca da parte aérea, raiz e total em relação às demais cultivares.

ABSTRACT The objective of this study was to evaluate the performance of three rice cultivars under saline water irrigation. The experiment was carried out in full sun at the Experimental Farm of the Unilab, in Redenção, Ceará, Brazil, in January 2016. The experimental design was completely randomized (CRD), in a 5 x 3 factorial scheme [irrigation water electrical conductivity (ECw: 0.5, 1.0, 2.0, 3.0 and 4.0 dS m-1) versus three rice cultivars (C1 - Ligeirinho, C2 - Casado and C3 - Meruinho)], totaling 15 treatments, with 4 replicates of 30 seeds per cultivar. After 21 days, the following variables were evaluated: emergence percentage (EP), emergence speed index (ESI), mean time of emergence (MTE), mean speed of emergence (MSE), shoot dry matter (SDM), root dry matter (RDM) and total dry matter (TDM). The cultivar Ligeirinho showed higher tolerance to saline stress with respect to the emergence percentage, emergence speed index and mean speed of emergence. The cultivar Casado showed higher tolerance to saline stress for shoot dry matter, root dry matter and total dry matter in comparison to the other cultivars.

In the present work we develop a theoretical study to analyze how the image charges effects can modify the electronic properties in Si and SrTiO3-based quantum wells. We have used the method based on the calculation of the image charge potential by solving Poisson equation in cylindrical coordinates. The numerical results show that the electron-heavy hole recombination energy can be shifted by more than 200 meV due to the combination of charge image and SiO2 (SrTiO3) interface thickness effects.

The energy spectrum and optical absorption of confined carriers in ellipsoidal CdSe quantum dots are calculated. Our model relies on the effective mass approximation and Fermi's golden rule for the electronic structure and optical properties, respectively. We demonstrate that the electronic structure and the interband optical absorption are highly dependent on the ellipsoid aspect ratio.

We investigate the confined exciton properties in InGaN/GaN cylindrical quantum wires. We have solved numerically Schrödinger-like equations in the effective mass approximation and have found the energy levels and wavefunctions for confined electrons and holes, using these results to calculate variationally the confined exciton energy. A comparison was made between graded and abrupt quantum wires, showing that the existence of smooth interfaces enhances the confined exciton energy if the wire radius is smaller than 50 Å. We conclude that the existence of graded interfaces must be considered for a better description of the exciton based optical properties of InGaN/GaN quantum wires.

In order to analyze the charging effects on electronic spectrum of Silicon (Si) based quantum wells (QW's), we use a method based on the calculation of the image charge potential by solving Poisson equation in cylindrical coordinates. The numerical results shows that the confined electron ground state energy level can be shifted by more than 50 meV due to the contribution of the image charges to the confinement potential of the graded quantum well.

We perform a theoretical investigation of the absorption and emission properties of quantum confined SiC/SiO2 spherical quantum dots, focusing on the the size-dependent emission and absorption spectra of an independent single dot. We observed strong oscillations in the absorption lines as a consequence of the interband transitions rules, and a blue-shift of the emission spectra lines with the decrease of the quantum dot diameter.

Calculation of the Raman spectra of zinc{blende InN/AlN superlattices were carried out assuming the existence of an interface region with thickness deltavarying from zero to three monolayers. Frequency shifts up to 80 cm were observed for some of the optical frequencies when delta = 3. Many peaks appearing at the low frequency side, shift toward the center position of the spectrum. As a consequence, pairs of the Raman modes become quasi-degenerate giving rise to highly prominent structures in the spectrum, for delta = 2 and 3. These effects are tracked to localization of atomic displacements mainly at the interface regions.

The complex mobility of electrons in 3C - and 6H-SiC subjected to intense high frequency electric fields is calculated taking into account effects of band nonparabolicity. The electric field, given by a dc component plus an ac component in the frequency range 0.1-100 THz, is applied along the [0001] ([111]) direction in the hexagonal (cubic) polytype. The real electron mobility presents a characteristic maximum peaking around 6-8 THz, while the imaginary electron mobility is structured, with characteristic minimum and maximum around 2-3 THz and 20{30 THz, respectively. These mobilities are seen to smooth down for higher temperatures in both polytypes.