Water quality in reservoirs is often compromised in many regions worldwide by nutrients and trace metals. This demands continuous monitoring; however, analyses of large data sets collected during regular monitoring remain a difficult task. Multivariate techniques offer a fast and robust approach for interpreting complex results. The objective of this study was to check the efficacy of selforganizing maps (SOMs) as a tool to investigate biogeochemical processes. This tool can also help to illustrate influences of land use patterns on the water quality of reservoirs. Here we use the Itupararanga Reservoir in Brazil as a subtropical example. Vertical profiles were sampled from seven sites in the reservoir in a total of seven campaigns over 24 months. Next to physicochemical parameters in the water column (dissolved oxygen, Eh, pH, and temperature), levels of nutrients (NO 3 − , NH 4 + , and PO 4 3− ), transition and trace metals (Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn), and chlorophyll-a (Chla) were measured. These variables were correlated with land use using SOM. With this technique samples were classified into 17 distinct groups that showed distinct influences of spatial heterogeneity and seasonality. The analyses helped to reveal a seasonal stratification period, where Fe, Mn, and P were released from sediments. Nutrients and some metal inputs (Al and Fe) were related to agricultural, urban, and grass/pasture areas around the reservoir. Our approach also helped to explain physical and biogeochemical seasonality in the reservoir.
The results of this study suggest the potential use of seaweed extracts as a source of antifungal agents with low toxicity to control anthracnose in papaya and banana during storage.
INTRODUÇÃOA Aroeira (Schinus terebinthifolius) é uma árvore grande, de casca fina e escamosa. Possui folhas compostas por folíolos lanceolados e pontiagudos, numerosas flores, dispostas em pedículos, pequenas e brancas ou amarelo esverdeadas. O fruto é drupa vermelha e lustrosa, cujo cheiro se assemelha ao da pimenta. É originária do Peru, sendo também encontrada na Europa, Ásia e outras regiões da América. No Brasil, tem distribuição em todo território, sendo catalogadas ABSTRACT: Fungitoxic effect of essential oil from aroeira (Schinus terebinthifolius RADDI) on Colletotrichum gloeosporioides. This study evaluated the effect of essential oil from Schinus terebinthifolius fruit on the mycelial growth of the fungus Colletotrichum gloeosporioides in vitro and on the anthracnose development during the postharvest period of papaya fruits. The different oil concentrations were diluted in 8% Tween 80. For the in vitro experiment, PDA culture media were prepared at the concentrations of 0.05, 0.10, 0.25 and 0.50% essential oil. Negative control was prepared with PDA medium alone, while solvent control was prepared with PDA medium and 8% Tween 80. Fungal growth inhibition was directly proportional to the oil amount and the greatest inhibition was 79.07% at 0.50% oil concentration. For the in vivo experiment, papaya fruits were inoculated with the fungus in four treatments: with biofilm, with biofilm plus 0.50% oil, with the fungicide Prochloraz and control fruits. Although treatment with oil was efficient against the fungus, it was not commercially recommended since it presented high values of loss of fresh mass and firmness, as well as phytotoxicity symptoms. The oil has antifungal property against C. gloeosporioides both in vitro and in vivo; however, it is not recommended for papaya fruits due to its phytotoxicity.
O conhecimento do potencial solar é considerado uma informação essencial no dimensionamento e simulação do desempenho de sistemas que convertem radiação solar em energia elétrica ou calor disponível em fluídos, bem como em estudos agrícolas voltados ao manejo de irrigação e avaliação da produtividade potencial. Nem sempre as informações sobre a radiação solar incidente estão disponíveis e, por isso, torna-se importante o desenvolvimento de métodos capazes de estimar com acurácia a radiação solar. O presente estudo avaliou o desempenho de diferentes métodos de estimativa da radiação solar global (RG) em ambiente subtropical úmido brasileiro, a fim de determinar qual deles apresenta maior acurácia. As bases de dados meteorológicos utilizadas foram registradas pela estação meteorológica automática pertencente ao Instituto Nacional de Meteorologia (INMET) e instalada em Iguape, município localizado na porção paulista do Vale do Ribeira. Modelos empíricos foram calibrados e tomados como referência na avaliação do desempenho da Máquina de Vetores de Suporte (SVM) utilizando diferentes conjuntos de variáveis de entrada. Dentre os métodos testados, a SVM utilizando o conjunto de varáveis de entrada {R0, Tmax, Tmin, es max, es min} apresentou o melhor desempenho.Palavras-chave: modelos empíricos; Vale do Ribeira; SVM. ESTIMATING DAILY GLOBAL RADIATION FROM COMMON METEOROLOGICAL VARIABLES IN A HUMID SUBTROPICAL ENVIRONMENT ABSTRACT: Knowledge of solar potential is essential in the design and simulation of systems that convert solar radiation in electric power or available heat in fluids, as well as in agricultural studies focused on irrigation management and potential productivity assessment. Oftentimes, information about solar radiation are not available and, therefore, it becomes important the development of methods for obtain reliable data of solar radiation. The present study evaluated the performance of different methods of estimating global solar radiation (RG) in a Brazilian humid subtropical environment in order to determine which is more accurate. The meteorological databases used were registered by the automatic meteorological station belonging to the National Institute of Meteorology (INMET) and installed in Iguape, a municipality located in the São Paulo portion in the Ribeira Valley. Empirical models were calibrated and taken as reference in the performance evaluation of the Support Vector Machine (SVM) using different sets of input variables. Among the tested methods, the SVM using the set of input variables {R0, Tmax, Tmin, esmax, es min} presented the best performance.Keywords: empirical models; Ribeira Valley, SVM.
RESUMO O objetivo deste trabalho consistiu na aplicação de indicadores socioambientais em pisciculturas familiares localizadas na região do Vale do Ribeira, em área de Mata Atlântica, no sudoeste do estado de São Paulo. Para isso, foram identificadas 84 propriedades. Dessas, 40 foram selecionadas como unidades amostrais. Entre as principais características identificadas, 32% possuem lâmina d’água inferior a cinco hectares, com viveiros escavados em sistema semi-intensivo, 58% utilizam mão de obra familiar e 23% apontam a ausência de assistência técnica especializada como o principal problema enfrentado. A tilápia-do-nilo (Oreochromis niloticus) representa 57% das espécies produzidas em sistemas de monocultivo ou policultivo. Contudo, as pisciculturas familiares são classificadas como sistemas produtivos de pequeno porte, com destaque para a necessidade de adequação de recursos naturais, da capacidade de gestão e da eficiência das práticas de produção. Os indicadores sociais variaram de 0,75 a 1,00 para equidade salarial, proporção de autoemprego, uso de mão de obra local, inclusão de gênero e inclusão etária, demonstrando a capacidade que a aquicultura tem para auxiliar no desenvolvimento social local, por meio da geração de emprego e renda.
The present study examined changes that took place in the physiology of three species of Rhodophyta by analysing the concentration of pigments and non-structural carbohydrates, comparatively evaluating algae collected from nature and after 28 days of laboratory cultivation. Another objective of the study was to determine whether the species retain their antifungal potential after the period of laboratory cultivation, correlating the changes in physiology and those from bioactivity. After carrying out laboratory cultivation, the results indicated a trend, in the three species of macroalgae, towards a reduction in pigment concentrations, mainly in the phycobiliproteins. For the non-structural carbohydrates no response pattern of the macroalgae was observed for the conditions evaluated. Extracts from the macroalgae, Ochtodes secundiramea and Palisada flagellifera, after laboratory cultivation showed a significant increase in antifungal potential which could be positively correlated with the change in concentration and ratios of chlorophyll-a and accessory pigments. Applying techniques of laboratory cultivation to macroalgae was an efficient tool for gaining knowledge of the physiology, and for obtaining biomass and compounds having biotechnological applications, without impacting on natural populations.
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