We report calculated elastic integral, momentum transfer, and differential cross sections for vinyl iodide, obtained using the Schwinger multichannel method at the static-exchange and static-exchange plus polarization levels of approximation. To account for the permanent dipole moment of the molecule, we used the Born closure correction. Our results indicate the presence of two shape resonances—one with a σ ^* character and the other with a π ^* character—which are in excellent agreement with those obtained experimentally via electron transmission spectroscopy. Additionally, we propose an empirical scaling relation for the resonances related to C=C and C–I bonds.
Bidens pilosa L., Bidens alba (L.) DC., and Bidens subalternans DC., Asteraceae, are often misidentified because of their morphological similarities. The present study provides a comparative analysis of the morpho-anatomical characteristics, histochemical, and chemical fingerprints obtained by liquid chromatography mass spectrometry for these three species. Light microscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to characterize diagnostic structures. Histochemical assays and LC-MS were applied to obtain chemical information from leaf, stem, and root extracts, and multivariate chemometrics including principal component analysis were used to classify the datasets. The morpho-anatomical and histochemical analysis allowed the identification and differentiation of the three species; also, the LC-MS analysis revealed that the main compounds in Bidens extracts are phenolics, and using chemometrics methods was possible to discriminate by species and plant parts. Together, these complementary approaches provide a robust basis for distinguishing closely related Bidens species and support more reliable pharmacognostic identification.
Nitrite monitoring in drinking water is essential for public health due to its toxicological risks. Despite its relevance, the official Griess-based spectrophotometric method presents limitations such as bulky instrumentation, sample instability, and the need for centralized analysis. Electrochemical sensors offer a promising alternative for on-site and real-time detection; however, few have reached the market due to complex fabrication and insufficient analytical validation. In this work, we present a miniaturized and disposable electrochemical sensor for nitrite quantification in tap water. Gold nanostructures were electrodeposited onto screen-printed carbon electrodes via a one-step modification. As a key distinguishing feature, we conducted the full analytical validation directly in tap water - from calibration curve construction to all figures of merit, addressing matrix effects through the standard addition method. The sensor exhibited excellent linearity from 1 to 24 mu mol L- 1, with a limit of detection of 0.72 mu mol L- 1 and a limit of quantification of 2.18 mu mol L- 1, both below the maximum levels established by the World Health Organization (WHO), Environmental Protection Agency (EPA), and Brazilian National Environment Council (CONAMA). For the first time, intermediate precision was evaluated using a nested design that considered different days, electrodes, and replicates. The results showed minimal variation between electrodes and days, while repeatability represented the main source of variability - an issue inherently mitigated by the single-use nature of the electrodes. Accuracy ranged from 92 % to 98 %, and no interference was observed from common contaminants, confirming the sensor's selectivity. These results, along with a high Blue Applicability Grade Index (BAGI) score of 70.0, underscore the sensor's reliability for nitrite detection in real matrices and its strong potential for commercial application, bridging the gap between academic research and real-world implementation.
RESUMO Myrtaceae está entre as famílias de angiospermas mais ricas da Floresta Atlântica. O presente trabalho teve como objetivo realizar o tratamento taxonômico das espécies de Myrtaceae ocorrentes no Parque Natural Municipal das Dunas da Lagoa da Conceição (Estado de Santa Catarina, sul do Brasil), uma unidade de conservação constituída por restinga. Amostras da família provenientes do herbário FLOR e coletadas em expedições de campo foram estudadas. Foram registradas 10 espécies distribuídas em quatro gêneros, sendo nove espécies nativas, e Psidium guajava, que é naturalizada. Myrcia e Eugenia são os gêneros mais ricos (4 e 3 spp., respectivamente), seguido por Psidium (2 spp.) e Campomanesia (1 sp.). Myrcia brasiliensis e M. multiflora foram registradas pela primeira vez no Parque. Além das descrições morfológicas das espécies, estão disponíveis fotos em campo e de espécimes herborizados, notas taxonômicas e uma chave de identificação.
Este artigo investiga as configurações da representação da mulher na literatura contemporânea de autoria feminina negra, enfocando as dinâmicas de identidade e resistência em um contexto transatlântico. O corpus de análise é constituído pelos romances O Caminho de Casa (2017), de Yaa Gyasi; A Contagem dos Sonhos (2025), de Chimamanda Ngozi Adichie; Meridiana (2025), de Eliana Alves Cruz; e a trilogia de Tsitsi Dangarembga (Condições Nervosas [1988], O Livro do Não [2006] e Esse Corpo Lamentado [2018]). A fundamentação teórica ancora-se nos estudos pós-coloniais, mobilizando conceitos de autores como Fanon, Spivak, Said e Ashcroft et al. Metodologicamente, a pesquisa utiliza a leitura em contraponto para examinar como as protagonistas transitam de estados de silenciamento e subalternidade para o exercício da agência e da soberania discursiva. Os resultados indicam que, embora a opressão colonial se manifeste de forma metamórfica - da violência física fundacional às sutilezas do racismo institucionalizado e do vestibular diário da excelência -, a literatura de autoria feminina negra opera como um ato de insubordinação epistêmica. Conclui-se que essas narrativas preenchem as lacunas da historiografia oficial, transformando a experiência da diáspora e da marginalidade em territórios de emancipação e reconstrução identitária.
