Anais da Academia Brasileira de Ciencias最新文献

The thermal conductivity of polyethylene glycol (PEG)-nanocomposites is crucial for their use in thermal management systems, underscoring the need for accurate predictive models. This study develops a Gradient Boosting Machine (GBM) model optimized with four algorithms: Batch Bayesian Optimization (BBO), Evolution Strategies (ES), Bayesian Probability Improvement (BPI), and Gaussian Processes Optimization (GPO). A dataset of 229 experimental samples (90% training, 10% testing) was employed, using temperature, PEG molecular weight, nano concentration, and nano type as input variables. K-fold cross-validation minimized overfitting. Model performance was evaluated with R-squared (R²), mean squared error (MSE), average absolute relative error (AARE%), and runtime. Correlation analysis showed nano concentration had the strongest impact on conductivity (0.75), followed by PEG molecular weight (0.56), while temperature (0.33) and nano type (0.24) were weaker predictors. Among the algorithms, GBM-ES achieved the best accuracy (R² = 0.9966 training, 0.9158 testing), outperforming the other methods and traditional linear regression, which showed far lower precision. GPO was the most computationally efficient (153.6 s), while BBO was slowest (274 s). Sensitivity analysis confirmed the dominant role of nano concentration and molecular weight. Overall, the optimized GBM models provide reliable, data-driven tools for predicting PEG-nanocomposite conductivity, reducing dependence on costly experimental work.

The Neotropical region harbors rich biodiversity, with aquatic insects playing key ecological roles. Despite research advances, challenges like taxonomic gaps and logistics persist. The seventh Neotropical Aquatic Insects Symposium (VII SIAN; Belém, 2025) gathered 410 participants and 364 abstracts on ecology, taxonomy, biomonitoring, and outreach. Using bibliometric techniques, the presented abstracts were analyzed. Although the SIAN aims to reflect Neotropical research as a whole, the data analyzed in this study primarily represent the Brazilian scientific community (92% of the abstracts), and interpretations should be viewed in that context. Most studies were conducted in Brazil (92%), particularly in the states of Pará, Minas Gerais, and Maranhão. Streams were the most frequently studied environments (69.4%). The most addressed insect orders were Odonata (27.7%), Trichoptera (17.5%), and Ephemeroptera (14.6%). Regarding life stages, 48.9% of the studies focused on immature forms, and 41% on adults. The most prominent research areas were ecology (31.7%) and biomonitoring (26.4%), while taxonomy, conservation, and ecological interactions were less frequently explored. The study highlights the importance of institutional partnerships and the adoption of innovative methods, such as environmental DNA and integrative taxonomy. Additionally, citizen science initiatives have contributed to raising awareness and strengthening research on aquatic insects in the Neotropical region.

Scirtidae are beetles whose larvae are aquatic and can be found in various habitats. The objectives of this study were to explore several aquatic habitats in the Amazon biome in search of Scirtidae using different methods for collecting larvae and adults, to propose a new reproduction method, and to report new records. Eight aquatic habitats were sampled: temporary ponds, streams, lakes, rivers, and four types of phytotelmata, including bromeliads, wild banana trees (Strelitziaceae), bracts, and palm sheaths (Arecaceae). These surveys were conducted across six states of the Brazilian Amazon: Acre, Amapá, Amazonas, Pará, Rondônia, and Roraima. A total of 1,125 larvae were collected, of which 423 successfully developed into adults through laboratory rearing. In addition, 503 adult specimens were collected by sweeping vegetation and using traps. We also developed a laboratory rearing method capable of monitoring several larvae simultaneously to obtain adult specimens and biological information on immatures. As a result, four genera were recorded: Contacyphon, Ora, Scirtes and a new unnamed genus. The genus Contacyphon and the species Ora atroapicalis Pic, O. bivittata Pic, and O. depressa (Fabricius) were recorded for the first time in the Brazilian Amazon. Rearing allowed us to observe four different types of pupation.

Aquaculture is essential for food security and the yellowtail lambari is of great importance in Brazilian fish farming. Zophobas morio meal has emerged as a sustainable protein alternative for fish diets. This study evaluated the apparent digestibility of larval, pupal and adult meal of Z. morio in diets for lambari. The experiment, conducted at IFES and UFES, used 840 juvenile lambari. The animals were fed three times a day and feces were collected by the direct method eight times a days over a period of 22 days. The apparent digestibility coefficients (ADCs) for larva and pupa meal were significantly higher than the ADC for adult meal, due to their lower chitin content. Protein digestibility was highest for pupa meal, followed by by larva and by adult meal. Lipids of larva meal were more digestible than those of adult meal. There was greater gross energy utilization for larva and pupa meal than for adult meal. In conclusion, Z. morio meal is a promising feed for yellowtail lambari, especially that of the larval and pupal stages, due to its good digestibility and high nutritional value; adult meal has lower digestibility and requires additional treatments for improvement.

Leprosy is a chronic infectious disease that remains a public health challenge in Brazil, particularly in the Northeast Region, which still has a high incidence of cases. By analyzing the geographical distribution and demographic characteristics of patients, we aim to describe the sociodemographic profile of leprosy cases in the Northeast Region of Brazil between 2019 and 2023. An ecological analysis was conducted using data from the Notifiable Diseases Information System (SINAN). The variables studied included the frequency of diagnoses by state, sex, education level, race, age group, and clinical form of the disease. Prevalence was described based on the absolute frequencies of reported cases. A total of 49,719 cases of leprosy were reported in the region, with Maranhão, Pernambuco, and Bahia recording the highest numbers. Most cases occurred in male individuals (58%) and in people with low educational attainment. The multibacillary form was predominant (78%), and the most affected age group was between 40 and 69 years. Thus, leprosy remains a significant public health issue in the Northeast Region of the country, highlighting the need for effective control and prevention strategies, as well as improvements in epidemiological surveillance and early diagnosis.

This study investigated the population structure of four flatfish species - Achirus lineatus (n = 94), Citharichthys spilopterus (n = 216), Etropus crossotus (n = 104), and Symphurus tessellatus (n = 48) - in the Guaratuba Bay estuary, southern Brazil, along with the reproductive aspects of A. lineatus and C. spilopterus. Monthly sampling was conducted at six sites along the estuary from October 2012 to September 2013. A. lineatus was most abundant in spring and summer, while C. spilopterus and E. crossotus showed population peaks during summer and autumn. S. tessellatus was most common in spring and autumn. Females dominated the larger size classes across all species, with significant differences in sex ratios observed for C. spilopterus and E. crossotus in the mid-estuary zone. Most individuals were captured in intermediate size classes (A. lineatus, C. spilopterus, E. crossotus: 8.9-11.5 cm; S. tessellatus: 11.0-15.1 cm). All species were present across the entire estuarine gradient, except E. crossotus, which was absent from the inner estuary. For the analyzed species, the highest Gonadosomatic Index (GSI) values were recorded during the warmer months. These findings enhance our understanding of flatfish ecology in this estuary and provide essential data to support conservation and management efforts targeting both the environment and flatfish populations.

Osteoporosis compromises bone mineral composition and microarchitecture. Given the limited ability of current treatments to restore lost bone mass, prevention remains crucial in clinical practice. In the present study, we investigated the effect of vitamin K2, administered alone or in combination with calcium and vitamin D3, on ovariectomy-induced osteoporosis in rats. We assessed serum parameters, bone mineral content, bone strength, histomorphometry, radiography, and microtomography to evaluate trabecular volume and bone microarchitecture. Serum calcium levels were similar between ovariectomized rats supplemented with either vitamin K2 or calcium. Vitamin K2 protected against the loss of trabecular bone volume in ovariectomized rats. Supplementation with calcium and/or vitamin D3 showed inconsistent effects on bone mass. Histologic, microtomographic, and radiographic analyses provided similar results; however, microtomography was more effective in detecting differences between groups. In our study vitamin K2 helped in the treatment of bone loss, while calcium and vitamin D3 continued to demonstrate inconsistent effects.

The Solimões Formation is one of the most fossiliferous units of the Neogene to Pleistocene of South America. Its rocks represent fluvial lacustrine Paleo-Amazon environments providing a rich record of paleovertebrate remains, including fishes (e.g., Myliobatiformes, Siluriformes, Ceratodontiformes, Osteoglossiformes, Characiformes, †Acregoliathidae), squamates, testudines (e.g., Podocnemidae, Chelidae and Testudinidae), crocodyliforms (e.g., Crocodyloidea, Alligatoroidea and Gavialoidea), birds (e.g., Suliformes) and mammals (e.g., Metatheria Didelphimorphia, Xenarthra Cingulata and Pilosa, Rodentia, †Notoungulata, †Litopterna, †Astrapotheria, Proboscidea, Artiodactyla, Sirenia, Cetacea, Primates and Chiroptera). Most of these recovered materials were acquired during paleontological expeditions carried out between 1950s and 1970s in its outcrops along Juruá River, Acre state. Notable for their recovered fossils, the "Alto Juruá expedition" was one of these, with its discoveries incorporated into the RadamBrasil Project. Among the recovered materials is an isolated ziphodont tooth that was mentioned but not described or published. Analysis of this tooth indicates it probably belongs to the †Sebecus cf. S. huilensis, and confirms it as the first occurrence of †Sebecidae for the prolific Solimões Formation in Brazil. This discovery, in addition to expanding the geographic distribution of the †Sebecus genus to northern Brazil, is one of the most recent specimens related to the extinct hypercanivore sebecids.