954 research outputs found
O conceito e as práticas de avaliação formativa percecionados por professores de línguas / The concept and practices of formative assessment as perceived by language teachers
A avaliação formativa é entendida e realizada para verificar continuamente as aprendizagens que os alunos vão realizando, as suas dificuldades e erros, para uma intervenção pedagógica que promova as aprendizagens. Tendo este pressuposto por base, o estudo que aqui se apresenta visa mostrar as perceções dos professores de línguas sobre o conceito e as práticas da avaliação formativa. Para isso, foi utilizada uma metodologia de investigação qualitativa, concretizada pela recolha e análise documental e por entrevistas semiestruturadas a 14 professores de línguas (materna e estrangeira) de todos os grupos de recrutamento de um Agrupamento de Escolas do norte de Portugal. Os resultados obtidos indicam que os referidos professores percecionavam a avaliação formativa como uma modalidade de recolha e análise de informações contínuas e sistemáticas a partir de critérios de avaliação das tarefas de aprendizagem. Já as perceções sobre a prática daquela avaliação mostraram que não está restringida a um momento específico da aula, sendo integrada no processo de ensino e de aprendizagem e realizada com diversos instrumentos com vista à regulação do processo de ensino e de aprendizagem. Apesar de os professores de línguas ainda percecionarem a prevalência da testagem com fins sumativos, há uma intencionalidade em tornar as práticas da avaliação formativa em práticas recorrentes, dados os benefícios que lhe reconhecem no processo de ensino e de aprendizagem
Bioactivity effects of extracellular matrix proteins on apical papilla cells
Potent signaling agents stimulate and guide pulp tissue regeneration, especially in endodontic treatment of teeth with incomplete root formation. Objective: This study evaluated the bioactive properties of low concentrations of extracellular matrix proteins on human apical papilla cells (hAPCs). Methodology: Different concentrations (1, 5, and 10 µg/mL) of fibronectin (FN), laminin (LM), and type I collagen (COL) were applied to the bottom of non-treated wells of sterilized 96-well plates. Non-treated and pre-treated wells were used as negative (NC) and positive (PC) controls. After seeding the hAPCs (5×103 cells/well) on the different substrates, we assessed the following parameters: adhesion, proliferation, spreading, total collagen/type I collagen synthesis and gene expression (ITGA5, ITGAV, COL1A1, COL3A1) (ANOVA/Tukey; α=0.05). Results: We observed greater attachment potential for cells on the FN substrate, with the effect depending on concentration. Concentrations of 5 and 10 µg/mL of FN yielded the highest cell proliferation, spreading and collagen synthesis values with 10 µg/mL concentration increasing the ITGA5, ITGAV, and COL1A1 expression compared with PC. LM (5 and 10 µg/mL) showed higher bioactivity values than NC, but those were lower than PC, and COL showed no bioactivity at all. Conclusion: We conclude that FN at 10 µg/mL concentration exerted the most intense bioactive effects on hAPCs
Characterization of novel calcium hydroxide- mediated highly porous chitosan- calcium scaffolds for potential application in dentin tissue engineering
The aim of this study was to develop a highly porous calcium- containing chitosan scaffold suitable for dentin regeneration. A calcium hydroxide (Ca[OH]2) suspension was used to modulate the degree of porosity and chemical composition of chitosan scaffolds. The chitosan solution concentration and freezing protocol were adjusted to optimize the porous architecture using the phase- separation technique. Scanning electron microscopy/energy- dispersive spectroscopy demonstrated the fabrication of a highly porous calcium- linked chitosan scaffold (CH- Ca), with a well- organized and interconnected porous network. Scaffolds were cross- linked on glutaraldehyde (GA) vapor. Following a 28- day incubation in water, cross- linked CH scaffold had no changes on humid mass, and CH- Ca featured a controlled degradability profile since the significant humid mass loss was observed only after 21 (26.0%) and 28- days (42.2%). Fourier- transform infrared spectroscopy indicated the establishment of Schiff base on cross- linked scaffolds, along with calcium complexation for CH- Ca. Cross- linked CH- Ca scaffold featured a sustained Ca2+ release up to 21- days in a humid environment. This porous and stable architecture allowed for human dental pulp cells (HDPCs) to spread throughout the scaffold, with cells exhibiting a widely stretched cytoplasm; whereas, the cells seeded onto CH scaffold were organized in clusters. HDPCs seeded onto CH- Ca featured significantly higher ALP activity, and gene expressions for ALP, Col1, DMP- 1, and DSPP in comparison to CH, leading to a significant 3.5 times increase in calcium- rich matrix deposition. In sum, our findings suggest that CH- Ca scaffolds are attractive candidates for creating a highly porous and bioactive substrate for dentin tissue engineering.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155906/1/jbmb34586.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155906/2/jbmb34586_am.pd
Increased whitening efficacy and reduced cytotoxicity are achieved by the chemical activation of a highly concentrated hydrogen peroxide bleaching gel
Objective: This study was designed for the chemical activation of a 35% hydrogen peroxide (H2O2) bleaching gel to increase its whitening effectiveness and reduce its toxicity. Methodology: First, the bleaching gel - associated or not with ferrous sulfate (FS), manganese chloride (MC), peroxidase (PR), or catalase (CT) - was applied (3x 15 min) to enamel/dentin discs adapted to artificial pulp chambers. Then, odontoblast-like MDPC-23 cells were exposed for 1 h to the extracts (culture medium + components released from the product), for the assessment of viability (MTT assay) and oxidative stress (H2DCFDA). Residual H2O2 and bleaching effectiveness (DE) were also evaluated. Data were analyzed with one-way ANOVA complemented with Tukey’s test (n=8. p<0.05).Results: All chemically activated groups minimized MDPC-23 oxidative stress generation; however, significantly higher cell viability was detected for MC, PR, and CT than for plain 35% H2O2 gel. Nevertheless, FS, MC, PR, and CT reduced the amount of residual H2O2 and increased bleaching effectiveness.Conclusion: Chemical activation of 35% H2O2 gel with MC, PR, and CT minimized residual H2O2 and pulp cell toxicity; but PR duplicated the whitening potential of the bleaching gel after a single 45-minute session
O impacto do ultrassom point-of-care transtorácico no tempo de pausa entre as compressões torácicas durante a reanimação cardiopulmonar: revisão sistemática e metanálise
Objective: To value the impact of transthoracic point-of-care ultrasound (POCUS) on pause time between chest compressions during CPR. Methods: Systematic literature review in PubMed, Embase, Scopus, and Biblioteca Virtual em Saúde databases. The primary outcome of the meta-analysis was the difference in pause time between chest compressions in CPR with and without transthoracic POCUS. The secondary outcome was the return of spontaneous circulation of the manual verification and transthoracic POCUS groups. We used software R version 4.1.3 to perform all statistical analyses. Results: The search in the databases resulted in 6177 publications. However, only five met all inclusion criteria. Most of the studies were prospective cohorts. The mean age ranged from 56.5 to 66 years, and males were predominant in all studies. All showed longer pauses in the POCUS group. There was a statistical association between the use of POCUS and longer pauses between chest compressions with an MD of 3.88 (95% CI 2.76; 5.01; p-value < 0.0001). The additional exclusion of any of the five studies did not change the result, i.e., DM between the two groups continued to be statistically significant. Conclusion: The combined analysis of the data suggests that using the POCUS increases the pause time between chest compressions by an average of 3.88 seconds. However, further studies evaluating the impact on return to spontaneous circulation and mortality are necessary.Objetivo: Avaliar o impacto do ultrassom point-of-care (POCUS) transtorácico no tempo de pausa entre as compressões torácicas durante a reanimação cardiopulmonar. Métodos: Revisão sistemática da literatura nas bases de dados PubMed, Embase, Scopus e Biblioteca Virtual em Saúde. O desfecho primário da metanálise foi a diferença no tempo de pausa entre as compressões torácicas. O desfecho secundário foi o retorno da circulação espontânea dos grupos de verificação manual e POCUS transtorácicos. O software R versão 4.1.3 foi utilizado para realizar todas as análises estatísticas. A diferença no tempo de pausa foi expressa por meio da diferença de média (MD) com intervalo de confiança de 95% e o retorno à circulação espontânea por meio do risco relativo. O p-valor foi considerado estatisticamente significativo quando < 0,05. Resultados: A pesquisa nas bases de dados resultou em 6177 publicações, no entanto, apenas cinco foram incluídas. Houve uma associação estatística entre o uso de POCUS e pausas mais longas entre compressões torácicas com uma MD de 3,88 (95% CI 2,76; 5,01; p-valor < 0,0001). A exclusão adicional de qualquer um dos cinco estudos não alterou o resultado, ou seja, o DM entre os dois grupos continuou a ser estatisticamente significativo. Conclusão: A análise combinada dos dados sugere que a utilização do POCUS aumenta o tempo de pausa entre as compressões torácicas numa média de 3,88 segundos. Contudo, são necessários estudos randomizados controlados que avaliem o impacto no retorno à circulação espontânea
SECA E SALINIDADE NA RESPOSTA ANTIOXIDATIVA DE RAÍZES DE FEIJÃO CAUPI
A seca, a salinidade no solo são fatores ambientais que limitam o crescimento vegetal e a produtividade agrícola. No entanto, as plantas se aclimatam a esses estresses abióticos utilizando diversos sistemas de defesa fisiológicos. A comunidade científica vem a cada dia aumentando o interesse pelas respostas fisiológicas das plantas a condições de estresses ambientais, devido ao fato de muitos dos mecanismos utilizados, ainda não serem completamente compreendidos. Uma vez entendidas, as estratégias de reação aos estresses ambientais poderão ser utilizadas como ferramentas nos programas de melhoramento vegetal, para a produção de plantas economicamente importantes, que sejam mais resistentes a esses fatores. Considerando assim o estudo dos mecanismos envolvidos na defesa de plantas, em especial o feijão caupi aos estresses salino e seca, buscou-se reunir nessa revisão informações relevantes que possam nortear o desenvolvimento de pesquisas sobre a defesa bioquímica/metabólica de plantas aos estresses abióticos em questão
A AVALIAÇÃO DAS APRENDIZAGENS NA FORMAÇÃO INICIAL DE PROFESSORES: DISCURSOS DE PROFESSORES/FORMADORES
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
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