182 research outputs found
Effects of Merging Digital Elevation Models on Flood Modelling Results
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Frontiers in occupational health and safety management
This Special Issue of the International Journal of Environmental Research and Public Health is devoted to the “Frontiers in Occupational Health and Safety Management” [...
Microwave Synthesis of Silver Sulfide and Silver Nanoparticles: Light and Time Influence
UIDB/50025/2020
UIDP/50025/2020
UID/CTM/50025/2019
.Silver sulfide (Ag2S) is a low band gap material, which absorbs near-infrared light and is of great importance in areas such as nanotechnology and biomedicine. We report the influence of the starting reagents, synthesis time, and light radiation on the geometry and size of silver sulfide nanoparticles and on the fraction of metallic Ag obtained in a microwave reactor. The X-ray diffraction diffractograms confirmed that Ag2S is the main product if the reaction's precursor contains silver in the oxidation state of +1 and mostly metallic silver (Ag°) when it is +2. Small nanoparticles (∼6 nm) of spherical geometry are present in the transmission electron microscopy images for the synthesis performed with the lamp light ON, while with the light switched OFF, wider and hundreds of nanometers longer particles are observed. This discriminative effect occurs with shorter synthesis time duration (<10 min) but when the time of reaction is extended, the particles coalesce for both light and dark conditions. Overall, it was observed by photoluminescence that crystalline Ag and Ag2S 4-8 nm nanoparticles obtained in 15 min and light irradiation during synthesis have a clear relative increase of the radiative recombination channels of the charged carriers, which are typical of materials characterized by the involvement of low density of states inside the band gap.publishersversionpublishe
Effects of inter-annual freshwater inflow shifts on the community structure of estuarine decapods
The objective of this study was to evaluate how inter-annual changes in freshwater inputs have affected the decapod assemblages in the Guadiana estuary. Three major areas in the estuary were sampled during the summer, in 2001 (high inflow year and before the filling of the Alqueva dam), in 2002 (low inflow and after filling of the Alqueva dam), and in 2008 and 2009 (low inflow and after consolidation of the impacts of the Alqueva dam). A significant increase in total
decapod densities was recorded for the entire estuary, but especially in the upper estuary, after the closure of the dam in
2002. Changes in salinity, turbidity and temperature, which were mainly due to changes in freshwater input and climatic
influence (North Atlantic Oscillation index), had an important influence on the structure of the decapod crustacean
assemblages. The major conclusions of the study were that, following the construction of the Alqueva dam and regularization of the freshwater inflow, the decapod crustacean community in the Guadiana estuary changed and a shift of the dominant decapod species to upper zones of the estuary happened. These changes, and the presence of the non-native Palaemon macrodactylus in 2008 and 2009, further enhance the importance of estuarine monitoring studies to improve
ecologists’ knowledge on distinguishing and understanding natural changes and anthropogenic impacts in the ecosystem.Effets des variations interannuelles d’apports d’eau douce sur la structure d’une communauté estuarienne de décapodes. L’objectif de cette étude était d’évaluer comment les variations interannuelles d’apports d’eau douce affectent l’assemblage de décapodes dans l’estuaire du Guadiana. Trois grands domaines de l’estuaire ont été échantillonnés en été : en 2001 (année d’apports importants et avant le remplissage du barrage d’Alqueva), en 2002 (faible apport d’eau douce et après le remplissage du barrage d’Alqueva), en 2008 et 2009 (après la consolidation de l’impact du barrage d’Alqueva). Une augmentation significative de la densité totale des décapodes pour tout l’estuaire a été enregistrée, mais surtout dans l’estuaire supérieur, après la fermeture du barrage en 2002. Les variations de salinité, turbidité et température, principalement dues à des changements d’apports d’eau douce et à l’influence du climat (indice d’oscillation nordatlantique), ont eu une influence importante sur la structure des assemblages de crustacés décapodes. Les principales
conclusions de l’étude sont que, à la suite de la construction du barrage d’Alqueva et de la régulation de l’apport d’eau douce, la communauté de crustacés décapodes dans l’estuaire du Guadiana a changé et les principales espèces de décapodes se sont déplacées vers les zones supérieures de l’estuaire. Ces changements, ainsi que la présence de l’espèce non native Palaemon macrodactylus en 2008 et 2009, soulignent l’importance de surveiller l’estuaire dans le futur proche afin de pouvoir mieux distinguer et comprendre les changements naturels et les impacts anthropiques sur l’écosystème
Strategic environmental assessment in Tróia (Portugal)
Proceedings of the First International Conference on Coastal Conservation and Management in the Atlantic and Mediterranean, p. 91-98Over the last two decades, the Tróia peninsula (SW coast of Portugal) has been designated by the Portuguese authorities both as a protected area and as an area of tourism development. The private investor that took over the tourism developments in Tróia asked the Institute of Marine Research (IMAR) to undertake an SEA, to help frame
the design and management of the future resort. SEA results were changed by local/central government decisions,
granting “more” than stakeholder/owner’s proposal, in terms of loads and densities. This process, as well as the main
characteristics and results of the SEA, are presented and discussed
Exploring the Effect of Hierarchical Porosity in BEA Zeolite in Friedel-Crafts Acylation of Furan and Benzofuran
Hierarchical BEA zeolite was prepared through desilication or desilication followed by acid treatment. The catalytic performance of BEA zeolite samples was evaluated using Friedel-Crafts acylations with two substrates of different molecular sizes, furan (5.7 Å) and benzofuran (6.9 Å), in the presence of acetic anhydride as acylating agent. The application of the simplified Langmuir-Hinshelwood kinetic model showed that the size of the substrate leads to different catalytic activities, with improved rate constant and turnover frequency (TOF) solely in the presence of benzofuran for both desilicated and further acid treated samples. The mesopores developed during the zeolite treatments have an important role as transportation channels by reducing diffusion limitations. The application of Quantitative Structure–Property Relationships (QSPR) allowed the finding of the most relevant properties of the zeolite and substrate with impact on the catalytic parameters.publishe
Balancing act: tubulin glutamylation and microtubule dynamics in Toxoplasma gondii
This research was funded by FCT-Fundação para a Ciência e Tecnologia, I.P. (Portugal) through CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, project UIDB/00276/2020 and Laboratório Associado para Ciência Animal e Veterinária (AL4AnimalS) project LA/P/0059/2020.The success of the intracellular parasite Toxoplasma gondii in invading host cells relies on the apical complex, a specialized microtubule cytoskeleton structure associated with secretory organelles. The T. gondii genome encodes three isoforms of both α- and β-tubulin, which undergo specific post-translational modifications (PTMs), altering the biochemical and biophysical proprieties of microtubules and modulating their interaction with associated proteins. Tubulin PTMs represent a powerful and evolutionarily conserved mechanism for generating tubulin diversity, forming a biochemical 'tubulin code' interpretable by microtubule-interacting factors. T. gondii exhibits various tubulin PTMs, including α-tubulin acetylation, α-tubulin detyrosination, Δ5α-tubulin, Δ2α-tubulin, α- and β-tubulin polyglutamylation, and α- and β-tubulin methylation. Tubulin glutamylation emerges as a key player in microtubule remodeling in Toxoplasma, regulating stability, dynamics, interaction with motor proteins, and severing enzymes. The balance of tubulin glutamylation is maintained through the coordinated action of polyglutamylases and deglutamylating enzymes. This work reviews and discusses current knowledge on T. gondii tubulin glutamylation. Through in silico identification of protein orthologs, we update the recognition of putative proteins related to glutamylation, contributing to a deeper understanding of its role in T. gondii biology.info:eu-repo/semantics/publishedVersio
Balancing act: tubulin glutamylation and microtubule dynamics in Toxoplasma gondii
The success of Toxoplasma gondii (intracellular parasite) host cell invasion relies on the apical complex, a specialized microtubule cytoskeleton structure associated with secretory organelles. The genome encodes three isoforms of both α- and β-tubulin which are altered by specific post-translational modifications (PTMs), changing the biochemical/biophysical proprieties of microtubules, and modulating their interaction with associated proteins. Tubulin PTMs are a powerful and evolutionarily conserved mechanism to generate tubulin diversity, forming a biochemical ‘tubulin code’ that can be ‘read’ by microtubule-interacting factors. The T. gondii tubulin PTMs are: α-tubulin acetylation, α-tubulin detyrosination, Δ5α-tubulin, Δ2α-tubulin, α- and β-tubulin polyglutamylation, and α- and α-tubulin methylation. Tubulin glutamylation is a key candidate to assist microtubule remodeling in Toxoplasma, being involved in the regulation of microtubule stability, dynamics, interaction with motor proteins, and severing enzymes. The correct balance of tubulin glutamylation is achieved by the coordinated action of polyglutamylases and deglutamylating enzymes. In this work, we will review and discuss the current knowledge on T. gondii tubulin glutamylation. By in silico identification of mammalian protein orthologs, we explored and updated the identification of putative proteins related to glutamylation, contributing to a better understanding of the role of tubulin glutamylation in T. gondii.info:eu-repo/semantics/publishedVersio
Neuromuscular assessment of a stand-up paddle stroke
his study analyzed muscle activity during the stand-up paddle stroke, considering the paddling side and the adjacent and opposing muscles relative to the position of the arms during paddling. Methods: Fourteen male paddleboarders performed three trials covering 195 m in which surface electromyography of the upper trapezius, biceps brachii, triceps brachii, tibialis anterior, and gastrocnemius medialis were recorded (four-cycle strokes on each side). The data were processed according to percentage of maximum voluntary contraction (% MVC). The MVC activation values (µV) for each muscle were then calculated and presented as percentage MVC (% MVC). Results: The recovery phase accounted for 60% of the paddle cycle, while the pull phase represented 39%. During right-side paddling, higher % MVC was found in the opposite-side upper trapezius (24.35%, p < 0.01) during the pulling phase and in the adjacent biceps brachii (8.36%, p < 0.03) during the recovery phase. In left-side paddling, greater % MVC was found in the opposite-side upper trapezius (27.60%, p < 0.01) during the pulling phase and in the opposite-side triceps brachii (42.25%, p < 0.04) during the recovery phase. Furthermore, the pulling phase exhibited higher MVC in the opposite-side upper trapezius compared to the recovery phase, both in the right-side (24.35%, p < 0.03) and left-side (27.60%, p < 0.01) paddling. Conclusions: these findings help establish the muscular activity of both sides of the paddling technique and the differences between the upper and lower limbs.info:eu-repo/semantics/publishedVersio
- …