Literacia científica, literacia matemática e pensamento crítico

Em muitos países, defende-se e preconiza-se, hoje, que o ensino das ciências e da matemática nos ensinos básico e secundário deve reger-se por princípios que promovam o pensamento crítico, a literacia científica e a literacia matemática de todos os alunos. Nesta linha, em conjugação com o facto de o PC emergir como proeminente e estreitamente ligado à literacia científica e matemática, importa clarificar perspectivas e evidenciar pontos de convergência, zonas de confluência entre PC, literacia científica e literacia matemática (PC/LC/LM). Tal poderá ajudar não só a rever, ponderar e potenciar orientações curriculares e práticas de ensino, mas também a equacionar a problemática da formação de professores

Comparison of (Th-U-233) O-2 and (Th-U-235) O-2 fuel burn up into a thermal research reactor using MCNPX 2.6 code

Gholamzadeh, Z (Gholamzadeh, Z); Tenreiro, C (Tenreiro, C.). Talca Univ, Dept Phys, Talca, Chile.Background: Decrease of economically accessible uranium resources motivates consideration of breeding of fertile elements such as thorium. Material and Method: Thorium oxide fuel burn up calculation of a simulated research reactor cooled heavy water has been proposed in the present work using MCNPX 2.6 code. Two U-233 and U-235 isotopes have been used as fissile element of thorium oxide fuel. Xe-135 and Sm-149 reactivity variations has been studied in the core loaded (Th-U-233)O-2 or (Th-U-235)O-2 fuel matrixes during 3 months burn up process. Results: Thorium oxide having 4% U-233 burned 1 MW power results in less Sm-149 reactivity than thorium oxide having 4% U-235 burned in 0.5 MW power. Xe-135 reactivity has an overestimated shift by 15 days in the core operated in 0.5 MW than the other, after 15 days both the cores behave similarly. 480 g of U-235 burns into the core using 0.5 MW power and 364 g of U-233 invents after 3 months. Burn up calculation of the modeled core of (Th-U-233)O-2 fuel shows a fissile mass reduction by 60 days while the consumed fissile mass reaches to its initial value after 120 days. The core flux is constant during 3 months for both modeled cores. A considerable negative reactivity occurs up to 15 days in both cores which can be refer to xenon inventory during thistime and then neutron multiplication factor is steadier up 3 months. Conclusion: Breeder thorium fuel enriched U-233 make several advantages of good neutronic economy, U-233 inventory and less inventory of long-lived alpha emitter waste

Acacia longifolia: A Host of Many Guests Even after Fire

Acacia longifolia is a worldwide invader that cause damage in ecosystems, expanding largely after wildfires, which promote germination of a massive seed bank. As a legume, symbiosis is determinant for adaptation. Our study aims to isolate a wider consortium of bacteria harboured in nodules, including both nitrogen and non-nitrogen fixers. Furthermore, we aim to evaluate the e ects of fire in nodulation and bacterial diversity on young acacias growing in unburnt and burnt zones, one year after the fire. For this, we used molecular approaches, M13 fingerprinting and 16S rRNA partial sequencing, to identify species/genera involved and 15N isotopic composition in leaves and plant nodules. Nitrogen isotopic analyses in leaves suggest that in unburnt zones, nitrogen fixation contributes more to plant nitrogen content. Overall, A. longifolia seems to be promiscuous and despite Bradyrhizobium spp. dominance, Paraburkholderia spp. followed by Pseudomonas spp. was also found. Several species not previously reported as nitrogen-fixers were identified, proposing other functions besides ammonia acquisition. Our study shows that bacterial communities are di erent in nodules after fire. Fire seems to potentiate nodulation and drives symbiosis towards nitrogen-fixers. Taken together, a multifunctional community inside nodules is pointed out which potentiate A. longifolia invasiveness and adaptation.info:eu-repo/semantics/publishedVersio

Retinal progression biomarkers of early and intermediate age-related macular degeneration

Funding Information: Funding: This work was supported by Fundação para a Ciência e Tecnologia project PTDC/MED-PAT/30385/2017 and iNOVA4Health-UIDB/04462/2020, a program financially supported by Fun-dação para a Ciência e Tecnologia/Ministério da Educação e Ciência, Portugal, through national funds and co-funded by FEDER under the PT2020 Partnership Agreement. Funding Information: This work was supported by Fundação para a Ciência e Tecnologia project PTDC/MEDPAT/30385/2017 and iNOVA4Health-UIDB/04462/2020, a program financially supported by Fundação para a Ciência e Tecnologia/Ministério da Educação e Ciência, Portugal, through national funds and co-funded by FEDER under the PT2020 Partnership Agreement. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Early and intermediate AMD patients represent a heterogeneous population with an important but variable risk of progression to more advanced stages of the disease. The five-year progression from early and intermediate AMD to late disease is known to range from 0.4% to 53%. This wide variation explains the particular interest in searching predictive AMD biomarkers. Clinical parameters such as drusen size, presence of pigmentary abnormalities, and fellow eye status were, traditionally, the more important predictive elements. Multimodal retinal assessment (Color Fundus Photography, Optical Coherence Tomography, Optical Coherence Angiography and Fundus Autofluorescence) is providing new and accurate image biomarkers, useful in research and in daily practice. If individual progression risk could be anticipated, then management plans should be adapted accordingly, considering follow-up intervals and therapeutic interventions. Here, we reviewed the most important image progression biomarkers of early and intermediate AMD with relevant interest in clinical practice.publishersversionpublishe

Hamiltonian formulation of systems with linear velocities within Riemann-Liouville fractional derivatives

The link between the treatments of constrained systems with fractional derivatives by using both Hamiltonian and Lagrangian formulations is studied. It is shown that both treatments for systems with linear velocities are equivalent.Comment: 10 page

Saccharomyces cerevisiae as a toxicological model to study synthetic cannabinoids and its pyrolysis products

Poster presented at the 7th European Academy of Forensic Science Conference. Prague, 6-11 September 2015"Synthetic cannabinoids are among the major psychoactive drugs widespread as safe and legal alternatives to cannabis. They are commercially available as herbal incense products intended for smoke. This has led most of developed countries to concentrate efforts in order to ban the so called “legal highs”. Despite of their increasing use, there is still a lack of information on both synthetic and natural ingredients, pharmacokinetic properties and toxic effects. In fact some of the substances seem to have stronger toxicological effects when compared to their legal counterpart. Toxicological assays are paramount to know how harmful these new substances are, helping increase public awareness since several hospitalization cases have been reported due to consumption. To tackle the new challenges posed by novel drugs worldwide, we developed an approach using Saccharomyces cerevisiae as a model to investigate the toxicity of pyrolysis products of synthetic cannabinoids. S. cerevisiae.