Universidade Federal do Rio Grande (FURG)
Recent publications
The increasing development of industry, ports, tourism, and commerce along the coasts poses a severe threat to local forests due to elevated levels of pollutants. An effective way to assess the impact of this contamination is by evaluating living organisms' anatomical features and chemical composition. This research examined the potential of Clusia criuva Cambess leaves as a bioindicator model for screening sandy coastal plain forests (Restingas). The study collected samples from pristine (PA) and disturbed (DA) areas, confirmed through literature review and sediment concentration by guidelines analysis. Microscopy images of the leaves revealed that PA samples are thicker and have fewer druse crystals than DA. Mass spectrometry fingerprint analysis identified key compounds such as flavonoids, benzophenones, and phenolic acids (FIA-ESI-IT-MS/MS), which could be considered chemical markers from the genus. The chemical composition of extracts from PA and DA differed significantly, with a low similarity index (40%). Quinic acid derivatives are found only in plants from PA, which may be a response against intense herbivory agents. Instead, 7-epi-nemerosone, was detected only samples from DA, probably due to the need to defend against oxidative stressors. Besides, the similarity between each study area's three distinct sampling points was around 80%, indicating low chemical variability within the exact location. This study demonstrates an integrative methodology for assessing and supporting the environmental status of Restinga ecosystems, ensuring a comprehensive response that can promote conservation strategies.
RESUMO O sistema discursivo de Periodicidade proposto por Martin (1992) e Martin e Rose (2007) para a análise do fluxo discursivo em textos é fundamentado na Linguística Sistêmico-Funcional (Halliday 1967, 1985, 1994; Halliday & Matthiessen 2004, 2014), mais precisamente nos conceitos hallidayanos de Tema e de Informação Nova (Novo), além dos conceitos de progressão temática e de hiperema (Daneš 1974) e de método de desenvolvimento textual e ponto (Fries 1981; 1995). Neste artigo, analisamos como ocorre o fluxo de informação em um texto argumentativo, verificando a relação dos Temas em diferentes níveis (hiperTemas e macroTemas) com o método de desenvolvimento e sua relação com o gênero de texto exposição de um ponto de vista. Também averiguamos a relação dos Novos oracionais com o macroNovo, o qual foca na expansão dos significados ideacionais em torno do campo do texto e coincide com a etapa de Reiteração da tese. Constatamos, no texto analisado, um método de desenvolvimento simples, com uma hierarquia de periodicidade em que unidades menores do discurso se estruturam dentro de unidades maiores.
This study explores the fabrication of nanofibers using different types of gelatins, including bovine, porcine, and fish gelatins. The gelatins exhibited distinct molecular weights and apparent viscosity values, leading to different entanglement behavior and nanofiber production. The electrospinning technique produced nanofibers with diameters from 47 to 274 nm. The electrospinning process induced conformational changes, reducing the overall crystallinity of the gelatin samples. However, porcine gelatin nanofibers exhibited enhanced molecular ordering. These findings highlight the potential of different gelatin types to produce nanofibers with distinct physicochemical properties. Overall, this study sheds light on the relationship between gelatin properties, electrospinning process conditions, and the resulting nanofiber characteristics, providing insights for tailored applications in various fields.
RESUMO Neste artigo apresentamos a análise de uma experiência de implementação de uma Unidade de Ensino Potencialmente Significativa (UEPS), com base na Teoria da Aprendizagem Significativa de Ausubel, na disciplina de Matemática no terceiro ano do Ensino Médio. A UEPS composta por nove atividades abrange uma aplicação da geometria espacial, com foco na transposição do conteúdo de redes cristalinas através de atividades práticas. Esta pesquisa qualitativa utilizou múltiplos instrumentos de análise, incluindo depoimentos e avaliações dos estudantes e escritas da pesquisadora. A análise da experiência vivida durante o ano de 2022, demonstra que as atividades práticas tornaram as aulas mais interessantes e aumentaram a motivação dos estudantes para participar, inclusive nas atividades que envolviam cálculos, além de sugerir indícios de aprendizagem significativa. Palavras-chave: ABSTRACT In this article we present the analysis of an experience of implementing a Potentially Significant Teaching Unit (UEPS), based on Ausubel's Meaningful Learning Theory, in the Mathematics discipline in the third year of High School. The UEPS, composed of nine activities, covers an application of spatial geometry, focusing on transposing the content of crystalline lattices through practical activities. This qualitative research used multiple analysis instruments, including student statements and evaluations and the researcher's writings. The analysis of the experience during 2022 shows that practical activities made classes more interesting and increased students' motivation to participate, including in activities involving calculations, in addition to suggesting signs of significant learning.
The olive ridley turtle (Lepidochelys olivacea) is the least studied sea turtle species, despite being the most abundant. Few studies on its diet have been reported worldwide, which suggest an omnivorous diet. The objective of this study was to characterize ontogenetic changes in diet composition and habitat use of the species in southern Brazil using gastrointestinal tract (GIT) contents and stable isotope (δ¹³C and δ¹⁵N) analyses. GITs (n = 10) and skin (n = 34) samples from specimens found stranded on the coast of Rio Grande do Sul (RS; from 31° 20′ S–51° 05′ W to 33° 45′ S–53° 22′ W) and individuals from incidental captures in the local bottom pair trawl fishery were collected from 2014 to 2019. Eighteen food items were found in the GITs, where the hermit crab Loxopagurus loxochelis had the highest contribution to the species diet, followed by the gastropod Buccinanops monilifer and the crabs Hepatus pudibundus and Libinia spinosa. Stable isotope mixing models showed the hermit crab as the most assimilated prey to juvenile and adult individuals, followed by a small contribution of salps to juvenile specimens. Prey preferences indicate a predominant use of the neritic environment for adults and a use of both neritic and oceanic environments for juvenile individuals. These results demonstrated that juvenile and adult olive ridley turtles use the coast of RS as a feeding ground; therefore, this area should be considered when proposing conservation measures for the species.
Heavy metals pose a significant threat to animals in aquatic environments due to the adverse effects they exert. Species of the genus Artemia have been described as heavy metal tolerant, but the sensitivity/tolerance range for these species has not been established. In the present study, the toxicity of Cd, Cu, Zn and Ni as reported in the ECOTOX and Web of Science databases was examined for Artemia franciscana and compared with other species and taxonomic groups using an integrative ecotoxicity evaluation. The hazard concentration for 5% of the species (HC5) of acute toxicity tests (24-96 h), obtained through a species sensitivity distribution (SSD) indicated that Cu (0.02 mg/L) and Cd (0.03 mg/L) were the metals with the highest toxicity to aquatic animals followed by Zn (0.15 mg/L) and Ni (0.23 mg/L). In addition to the higher hazard of Cu and Cd to aquatic animals, the comparison of acute LC50 values for A. franciscana indicates lower toxicity of Cd followed by Cu, Zn, and Ni (200.0, 14.5, 9.5, and 0.6 mg/L, respectively). Using the SSD and physiological sensitivity (S) approaches, it was demonstrated that A. franciscana is relatively tolerant to Cd (SSD= HC99; S = 2.21), Cu (SSD= HC97; S = 2.00), Zn (SSD= HC90; S = 1.29) and Ni (SSD= HC83; S = 0.96) compared with other species and taxonomic groups. It appears that tolerance to the metals Cd, Cu, Zn and Ni is unique to the family Artemiidae within the order Anostraca, as the families Streptocephalidae and Thamnocephalidae are not tolerant (have negative S values). Our study confirmed that as expected, A. franciscana presents higher tolerance to Cd, Cu, Zn, and Ni than other aquatic animals. Our findings confirm that A. franciscana can be used as a model organism to understand mechanisms involved in tolerance to heavy metals, mainly Cd and Cu, which are considered highly toxic to other animals.
Stable isotope analysis is an approach that allows inferring feeding ecology and trophic structure of populations, especially for species that are difficult to observe in natural habitats, such as marine turtles. This study investigated the niche breadth of adult and juvenile green sea turtles (Chelonia mydas) through δ15N and δ13C values in carapace scutes. During 2017 and 2018, tissues were collected from juveniles in a feeding area in southeastern Brazil (n = 60) and from adults in a nesting area in northeastern Brazil, at Fernando de Noronha (n = 21). Our results revealed no temporal variations in the isotopic values of adult green turtles and the mean δ15N values are compatible with the isotopic values of primarily herbivorous animals. In southeastern Brazil, the δ13C values and isotopic niche breadth differences observed in juvenile green turtles suggest that variations in habitat (i.e., channel between the municipalities of Ilhabela and São Sebastião - “SSC” and region comprising the other two municipalities of Ubatuba and Caraguatatuba - “CAU”, as defined in this study based on oceanographic current dynamics) can influence their isotopic niche. The isotopic values observed in juvenile green turtles demonstrated a high degree of feeding behavior plasticity and individual variability, which were possibly influenced by the dynamic of oceanographic currents and seasonal nutrient inputs. These findings help to elucidate the feeding behavior of green turtles at different life stages and the potential influence of oceanographic current dynamics in key feeding sites for juvenile green turtles.
As Artes apresentam grande potencial contextualizador, além de motivacional no processo de ensino, podendo servir como recurso didático visando a Física Moderna. O objetivo desse artigo é mapear os trabalhos a respeito da união temática entre as Artes e a Física Moderna e/ou Contemporânea. A associação de Física e Arte no ensino pode propiciar a aprendizagem significativa dos temas a serem estudados e favorecer a inserção dos alunos na cultura científica, ou no desenvolvimento dessa. No intuito de explorar a transdisciplinaridade entre as culturas Física e Arte, fundamentada nas ideias de Teoria da Complexidade de Edgar Morin, foi realizada uma pesquisa nos principais repositórios com o objetivo de construir um Estado da Arte, que relacionam culturas como o cinema, a literatura, a música, o teatro, o cordel, os quadrinhos, a escultura, a pintura etc. e a Física Moderna. Os resultados indicaram uma carência histórica na exploração do tema, porém, recentemente, tem havido um aumento significativo de interesse e pesquisa nessa área.
Southern Hemisphere Megaptera novaeangliae undertake the longest migration, which reflect their exposure to lipophilic contaminants. To assess these changes, persistent organic pollutants were analyzed in blubber samples of humpback whales from three regions: the Antarctic Peninsula (n = 46), the Strait of Magellan, Chile (n = 22), and the Brazilian coast (n = 38). The similarity in PCB and HCB levels between individuals from feeding grounds and breeding grounds suggests contamination during feeding. The whales around the Antarctic Peninsula exhibited a predominance of tetrachlorobiphenyl PCBs. Whales feeding in the Strait of Magellan showed a slight prevalence of 5Cl biphenyls, likely due to their consumption of subantarctic krill species as well as small fishes potentially contaminated by industrial activities in Chile. The dominance of 5-6Cl congeners in whales in Brazil, may be attributed to the extreme physiological changes during fasting when whales utilize blubber reserves and metabolize lighter congeners, or transfer them to their calves.
The northern Antarctic Peninsula is a key region of the Southern Ocean due to its complex ocean dynamics, distinct water mass sources, and the climate-driven changes taking place in the region. Despite the importance of macronutrients in supporting strong biological carbon uptake and storage, little is known about their spatiotemporal variability along the northern Antarctic Peninsula. Hence, we explored for the first time a 24-year time series (1996–2019) in this region to understand the processes involved in the spatial and interannual variability of macronutrients. We found high macronutrient concentrations, even in surface waters and during strong phytoplankton blooms. Minimum concentrations of dissolved inorganic nitrogen (DIN; 16 μmol/kg), phosphate (0.7 μmol/kg), and silicic acid (40 μmol/kg) in surface waters are higher than those recorded in surrounding regions. The main source of macronutrients is the intrusions of Circumpolar Deep Water and its modified variety, while local sources (organic matter remineralization, water mass mixing, and mesoscale structures) can enhance their spatiotemporal variability. However, we identified a depletion in silicic acid due to the influence of Dense Shelf Water from the Weddell Sea. Macronutrient concentrations show substantial interannual variability driven by the balance between the intrusions of modified Circumpolar Deep Water and advection of Dense Shelf Water, which is largely modulated by the Southern Annular Mode (SAM) and to some extent by El Niño-Southern Oscillation (ENSO). These findings are critical to improving our understanding of the natural variability of this Southern Ocean ecosystem and how it is responding to climate changes.
Background Concern about the viability of skin flaps, especially those of random pattern, has been the subject of several studies in plastic surgery. The limiting factor of these flaps is the unpredictability of its microvasculature, which could lead to partial or complete necrosis of the flap. This study tested the role of topical use of linoleic acid on the survival of random skin flaps. This is a polyunsaturated fatty acid, which in wound healing studies showed to act by mediating the inflammatory response, and decreasing the production of nitric oxide, accelerating the repair process. Objective The aim of this project was to evaluate morphometric and histologically the improvement on skin flaps survival in rats treated with topical linoleic acid. Method 24 male Wistar rats randomly divided into 3 groups, the control group or Glycerin (GG, n = 8), Dersani® group (GD, n = 8) and Linoleic Acid group (GL, n = 8). Under general anesthesia, a cranial base modified McFarlane random skin flap was elevated in dorsal region of the rats. Results The mean percentage of necrosis area among the groups was: GG - 44.49%, GD - GL and 44.72% - 44.20%. It showed no statistically significant differences (p> 0.05). Histological analysis has also not found differences in the degree of necrosis or inflammation. Conclusion In this study, topical application of LA showed no statistically significant dif-ferences (P>0.05) on improving the survival area of random skin flap in rats. Keywords: Rats; Ischemia; Reperfusion; Surgical Flaps; Linoleic Acid
DNA Barcoding is an important tool for disciplines such as taxonomy, phylogenetics and phylogeography, with Barcode of Life Data System (BOLD) being the largest database of partial cytochrome c oxidase subunit I (COI) sequences. We provide the first extensive revision of the information available in this database for the insect order Thysanoptera, to assess: how many COI sequences are available; how representative these sequences are for the order; and the current potential of BOLD as a reference library for specimen identification and species delimitation. The COI database at BOLD currently represents only about 5% of the over 6400 valid thrips species, with a heavy bias towards a few species of economic importance. Clear Barcode gaps were observed for 24 out of 33 genera evaluated, but many outliers were also observed. We suggest that the COI sequences available in BOLD as a reference would not allow for accurate identifications in about 30% of Thysanoptera species in this database, which rises to 40% of taxa within Thripidae, the most sampled family within the order. Thus, we call for caution and a critical evaluation in using BOLD as a reference library for thrips Barcodes, and future efforts should focus on improving the data quality of this database.
This research aims to evaluate the impact and repercussions of sea surface temperature anomalies (SSTA) on the spatiotemporal variability of precipitation in the Upper Iguaçu (UIW), Upper Ribeira (URW), and Coastal (CW) watersheds, located in the eastern region of the state of Paraná and the southern region of Brazil. Methodological procedures used in this research include clustering analysis (K-means) to obtain homogeneous pluviometric groups in each watershed and a vector autoregressive model (VAR) to analyze the correlation between pluviometric anomalies and maritime indicators such as the El Niño-Southern oscillation (ENSO) indicators Southern oscillation index (SOI) and Oceanic Niño index (ONI), the Pacific Decadal oscillation (PDO), and the Tropical Atlantic meridional gradient (TAMG), using data provided by the National Oceanic and Atmospheric Administration (NOAA). The spatial analysis revealed a rainfall structure of higher yearly amounts in the coastal watershed and leeward of the Serra do Mar, while an expressive sector of the Ribeira watershed presents a significant reduction of the yearly rainfall amounts compared to the sea coast. The VAR model has shown that the ONI climate indicator had the greatest significance and spatial breadth in determining the rainfall anomalies in the study area. Six out of the fifteen homogeneous groups identified in this study have rainfall anomalies related to one of the three maritime indicators (SOI, PDO, or ONI) with a predominance of a lag of 2 to 3 months. Graphical abstract
“Surf diatoms” can form high biomass in the surf zone of sandy beaches around the world, Asterionellopsis and Anaulus being the main genera of this group in Brazil. Asterionellopsis glacialis was considered a cosmopolitan species, and taxonomic studies using molecular and morphological tools showed that A. glacialis is a complex with cryptic and semicryptic species. So, it would be plausible to suppose that Anaulus australis , another surf zone patch-forming diatom with wide latitudinal occurrence could also be part of a species complex. We collected and identified Anaulus and Asterionellopsis strains from tropical, subtropical and warm temperate sandy beaches on the east coast of South America (Brazil) based on genetic divergence, phylogeny, single-locus automated species delimitation methods (both genera), and frustule ultrastructure ( Anaulus ). Anaulus and Asterionellopsis showed contrasting diversity patterns and spatial distribution: a single species of Anaulus australis was registered in tropical and subtropical beaches, while at least three species of Asterionellopsis : A. tropicalis , A. thurstonii and A. guyunusae were observed at different latitudes, indicating that Asterionellopsis species have distinct ecological requirements. Asterionellopsis thurstonii was previously reported in Europe and it is documented here for the first time in the Southern Hemisphere. The different diversity patterns between these two surf diatom genera suggest that they are likely to have distinct ages, and dispersion and/or speciation processes.
Benzimidazoles and benzothiazoles are a class of pharmacologically potential compounds, which exhibited anti-microbial, anticancer, and anti-inflammatory activities. These can be obtained by simple condensation of o-phenylenediamine or o-aminothiophenol with aromatic aldehydes. The synthetic protocol can be accomplished/improved by varying reaction parameters such as temperature, solvents, and catalysts. To develop such condensation reactions in a sustainable way, non-toxic solvents and eco- friendly catalysts are presently used. In this study, we proposed a novel and interesting strategy for obtaining diversely substituted 2-phenyl benzimidazole and 2-phenyl benzothiazole derivatives via a one-pot protocol, employing pyrrolidinium ionic liquid as a green and environmentally benign catalyst under solvent-free conditions at room temperature in an open atmosphere. The resulting products were obtained in good to excellent yields within a short reaction time (3-20 min). A plausible mechanism was also discussed.
Electric motors are used in the majority of all-electric ship concepts to drive marine propellers. In spite of significant efforts to optimize the propeller selection, there is still a need for the development of propeller optimization methodologies that take into account the ship's operational requirements and match the propeller to an electric motor. In this paper, we employ an optimization procedure that minimizes the electric motor shaft power with respect to the propeller's design parameters in the Wageningen B-screw series. The optimization uses a differential evolution method to evaluate propeller designs while accounting for imposed limits in cavitation, tip velocity, and mechanical strength. The modeling consists of well-known parametric approaches overall but computational fluid dynamics is used for the still-water resistance instead. The optimization algorithm is exercised on an actual ferryboat. The optimization resulted in a 22% percent improvement in the objective function when comparing the worst configurations of initial and final populations. The longest running time was 2.8 hours in an AMD Ryzen 7 3700X 8-Core Processor @ 2200 MHz in which 2964 designs were assessed. Similar propeller designs were found for 7.0 and 7.5 knots, except for the expanded area ratio due to the cavitation limit. Geared drives with reductions of about 1.2 and 1.1 were optimal respectively for 7.0 and 7.5 knots, while open-water propeller efficiencies peaked at nearly 39% and 38%.
The Human Leukocyte Antigen G (HLA-G) is an immunoregulatory molecule with a critical role in pregnancy success. HLA-G alleles are associated with differential susceptibility to multiple conditions, including gestational problems, infectious diseases, and viral persistence. Of note, both herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) can impair HLA-G expression, interfering with HLA-G-associated immunoregulation. On the other hand, the impacts of HLA-G alleles on susceptibility to Herpesviridae infection is a neglected issue. Therefore, this study evaluated HLA-G allele frequencies and their associations with placental Herpesviridae infection in women from southern Brazil. Placenta samples were collected soon after delivery, and detection of viral DNA of HSV-1, HSV-2 and human cytomegalovirus (HCMV) was performed by polymerase chain reaction (PCR). A fragment of HLA-G (exons 2-4) was amplified by PCR, sequenced, and analyzed to allele determination. One hundred and seventy women had their alleles determined. Overall, 25 HLA-G alleles were found, distributed into 56 different genotypes. The most frequent alleles were G*01:01:01 and G*01:01:02, found in 37.9% and 16.5% of samples, respectively. Among the 170 women, 89 (52.4%) tested positive for Herpesviridae DNA in the placenta, 55 (32.3%) tested negative, 3 (1.8%) were negative for HSV-1 and HSV-2 (with absent HCMV data), and 23 (13.5%) were undetermined. The G*01:01:01 allele was significantly associated with an increased risk of placental HSV-1 infection (p=0.0151; OR=1.837; IC=1.108-3.045). This study describes new information concerning placental HLA-G alleles in women from southern Brazil and helps explain how genetic background can modify susceptibility to placental infections.
This work evaluates the influence of the reference trajectory on the tracking error in a servo-positioner control system. Thus, the objective is to improve the ideal tuning of the gains of a controller applied to the tracking of the positional trajectory of a hydraulic actuator through the physical characteristics of the plant and the trajectory. The applied controller uses a cascade strategy and consists of dividing the mathematical model into two interconnected subsystems, one hydraulic and the other mechanical, applying specific control strategies to each subsystem. The proposed methodology is implemented using the Firefly Metaheuristic Algorithm (FMA). The first stage consists of generating the 5th order optimal trajectories by means of b-splines functions, in which they must minimize the acceleration along the actuator's path, considering speed and flow restrictions related to the hydraulic servo-position. The second step consists in determining the effective value of the error during the execution of the trajectory and the respective gains applied to the model. The results show that this strategy proved to be useful for obtaining adequate trajectories and gains in plants with significant non-linearities, because the trajectory error was 27% lower than the empirical adjustment method of gains compared in this study.
In 2019, the largest oil spill ever recorded in tropical oceans in terms of extent occurred in Brazil. The oil from the spill was collected directly from the environment and used in an exposure experiment with the endangered reef-building coral Mussismilia harttii. The treatments of the experiment were control (without oil), 1% oil, 2.5% oil, and direct contact of coral with oil. The most abundant hydrocarbon in the seawater of the experiment was phenatrene, which is toxic to corals. However, overall, the concentration of PAHs was not very high. The analysis of the maximum photosynthetic capacity of Symbiodiniaceae dinoflagellates showed a small impact of oil on corals, mainly on the contact treatment. However, coral microbiomes were affected in all oil treatments, with the contact treatment showing the most pronounced impact. A greater number and abundance of stress-indicating and potentially pathogenic bacteria were found in all oil treatments. Finally, this highly weathered oil that had lain in the ocean for a long time was carrying potentially coral-pathogenic bacteria within the Vibrionaceae family and was able to transmit some of these bacteria to corals. Bacteria within Vibrionaceae are the main causes of disease in different species of corals and other marine organisms.
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Pedro Silva
  • Faculty of Medicine - Famed
Silvina Botta
  • Institute of Oceanography - IO
Erik Muxagata
  • Institute of Oceanography - IO
Marta Regina Cezar-Vaz
  • School of Nursing - EEnf
Simone Karam
  • Departamento Materno-Infantil
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