In this paper we consider the submonoids OPDI_n, MDI_n and ODI_n of the dihedral inverse monoid DI_n of all orientation-preserving, monotone and order-preserving transformations, respectively. Our goal is to exhibit presentations for each of these three monoids.

Solid state reaction was used to produced barium titanate modified with calcium (BCT) showing the presence of the piezoelectric tetragonal phase after sintering at 1350 °C. Bioglass 45S5 (BG) was synthetized by sol-gel route. From these two materials and commercial hydroxyapatite (HAp) were obtained composites. The BG produced showed some cytotoxic character that was weakened by passivation. All other materials were non-cytotoxic. Contact polarization at constant temperature was chosen composites polarization. Electric/dielectric properties were evaluated by thermally stimulated depolarization currents (TSDC). The material showed bioactivity with the composite with BCT/BG/HAp 90/5/5 (wt%) showing increased bioactivity. In vitro test showed high proliferation rates for the composites.

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The cucurbit[8]uril (CB8) synthetic receptor is shown to form high-affinity host–guest complexes with dicationic dithienylethene (DTE) photoswitches in water. ITC experiments combined with computational studies suggest that the formation of the inclusion complexes is mainly driven by a combination of hydrophobic effects, ion–dipole, hydrogen- and chalcogen-bonding interactions. The binding affinities were observed to be much higher for the DTE closed isomers, reaching values in the picomolar range (up to 1011 M−1) while the open isomers display up to 10 000-fold lower affinities, setting ideal conditions for the development of robust photoswitchable host–guest complexes. The light-responsive affinity of these photoswitches toward CB8 was explored to control the encapsulation and release of nanomolar affinity steroids via competitive guest replacement.

ABSTRACTAlbanerpetontidae form an enigmatic extinct group of lissamphibians, ranging from the early Bathonian to the early Pleistocene. The Upper Jurassic outcrops of Portugal yield a large collection of material, suitable for addressing the intraspecific variation in and diagnostic potential of the characteristic fused frontals. We revise 58 specimens from the Guimarota beds of the Kimmeridgian Alcobaça Formation and describe 62 new frontal bones from the Kimmeridgian ? Tithonian Lourinh? Formation. Smaller specimens exhibit a vermicular dorsal ornamentation, while it is polygonal in larger specimens and other albanerpetontids. Compared to small specimens, larger specimens display: (1) larger ventrolateral crests extending posteriorly after the parietal margin; (2) a relatively shorter internasal process; (3) a frontal width across posterior edges relatively smaller; and (4) a ventromedian crest less pronounced. Morphometric analyses suggest a single species with different ontogenetic stages. Specimens are attributed to aff. Celtedens sp., based on a bell-shaped outline with a curved orbital margin (although variable in Portuguese specimens), and a flabellate, bulbous-shaped internasal process. The species is more similar to C. megacephalus than C. ibericus, but its phylogenetic position comprises an unresolved trichotomy. Our results show that intraspecific variation and homoplasy render the fused frontal non-diagnostic below the generic level.

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O trabalho em plataformas digitais é uma nova forma de trabalho que, em Portugal, não tem ainda definido um modelo regulado de relações de trabalho. Este artigo analisa os perfis de trabalhadores de várias plataformas digitais de trabalho e a sua representação coletiva em Portugal. A diversidade encontrada nos estudos de caso dos perfis dos trabalhadores de cada plataforma explica, em parte, a falta de interesse de movimentos laborais em os representar. O tipo de tarefas e o local de trabalho contribuem para o desinteresse na procura de representantes coletivos, e demonstra os (des)alinhamentos que ocorreram entre trabalhadores e possíveis representantes. Observa-se ainda potencial para outros alinhamentos entre os interesses de diferentes trabalhadores, movimentos sindicais e associações de representação alternativa.

Teachers are central to the choice of tasks proposed to the students. And the teachers’ knowledge is one of the important elements guiding these choices. Despite the different models that conceptualize the teachers’ knowledge to integrate technology in their practices, research has focused essentially on the integration of a single technology. Little is known about how the work with different technologies can contribute to promote the development of the professional knowledge of pre-service teachers (PTs) or how the use of different technologies mobilizes different domains of the PTs’ knowledge. The main goal of this study is to deepen the understanding about the relation between the PTs’ Knowledge for Teaching Mathematics with Technology (KTMT) and their choice of tasks. The study adopts a qualitative and in-terpretative methodology based on one case study. The main conclusions suggest a strong impact of the PTs’ Learning and Teaching Technology Knowledge (a knowledge related to the impact of technology on the teaching and learning process) and a not so strong impact of their Mathematical and Technological Knowledge (a knowledge related to the impact of technology on the mathematical knowledge). The conclusions also point to the potential of the work with different technologies to deepen the PTs reflections and analysis of tasks.