Galaxy clusters, type Ia supernovae and the fine structure constant

As is well known, measurements of the Sunyaev-Zeldovich effect can be combined with observations of the X-ray surface brightness of galaxy clusters to estimate the angular diameter distance to these structures. In this paper, we show that this technique depends on the fine structure constant, $\alpha$. Therefore, if $\alpha$ is a time-dependent quantity, e.g., $\alpha=\alpha_0 \phi(z)$, where $\phi$ is a function of redshift, we argue that current data do not provide the real angular diameter distance, $D_{\rm{A}}(z)$, to the cluster but instead $D_A^{data}(z) = \phi(z)^2 D_{\rm{A}}(z)$. We use this result to derive constraints on a possible variation of $\alpha$ for a class of dilaton runaway models considering a sample of 25 measurements of $D_A^{data}(z)$ in redshift range $0.023 < z < 0.784$ and estimates of $D_{\rm{A}}(z)$ from current type Ia supernovae observations. We find no significant indication of variation of $\alpha$ with the present data.Comment: 8 pages, 4 figures, To appear in JCA

Developing statistical literacy: Student learning and teacher education

Recent international and national mathematics curriculum guidelines indicate the development of students’ statistical literacy, at different levels of schooling, as a major educational aim. In Portugal, the mathematics syllabus for basic education, which began to be implemented in 2009, gave a greater emphasis on statistics, presenting more demanding learning goals, since the elementary levels. This represented a challenging situation for practicing teachers, requiring them to develop new perspectives about the teaching and learning of statistics. In this context, the project Developing statistical literacy: Student learning and teacher education was planned aiming to study the development of statistical literacy from elementary to secondary education, with special attention to two main issues: i) the characterization of key aspects of students’ statistical literacy, particularly regarding the ability to formulate questions, collect data and represent them to answer those questions, and ii) the development of statistical and didactical knowledge for teaching in different schools levels. As the project unfolded, another research strand associated with students’ statistical reasoning and the necessary conditions for its development emerged

Hydrogels based on poly(vinyl alcohol) for cartilage substitution

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

Sponge perforating lace coral with anticancer activity

This short note reports results from a pilot study to investigate new anticancer agents from deepsea corals in which colonizing sponges were encountered. The pure white stylasterid coral fans of Errina dabneyi (Pourtalès, 1871) are a conspicuous feature on the upper bathyal slopes in Azorean waters and can be found in depths from 215 to more than 500 m (Wisshak et al. 2009; Braga-Henriques et al. 2013). From the 26 species of Errina known worldwide (most from deeper waters) (Cairns 1983), E. dabneyi seems to be endemic to the Azores Archipelago and the adjacent Mid-Atlantic Ridge region (Zibrowius & Cairns 1992; Braga-Henriques et al. 2013). […]

About the sterilization of chitosan hydrogel nanoparticles

In the last years, nanostructured biomaterials have raised a great interest as platforms for delivery of drugs, genes, imaging agents and for tissue engineering applications. In particular, hydrogel nanoparticles (HNP) associate the distinctive features of hydrogels (high water uptake capacity, biocompatibility) with the advantages of being possible to tailor its physicochemical properties at nano-scale to increase solubility, immunocompatibility and cellular uptake. In order to be safe, HNP for biomedical applications, such as injectable or ophthalmic formulations, must be sterile. Literature is very scarce with respect to sterilization effects on nanostructured systems, and even more in what concerns HNP. This work aims to evaluate the effect and effectiveness of different sterilization methods on chitosan (CS) hydrogel nanoparticles. In addition to conventional methods (steam autoclave and gamma irradiation), a recent ozone-based method of sterilization was also tested. A model chitosan-tripolyphosphate (TPP) hydrogel nanoparticles (CS-HNP), with a broad spectrum of possible applications was produced and sterilized in the absence and in the presence of protective sugars (glucose and mannitol). Properties like size, zeta potential, absorbance, morphology, chemical structure and cytotoxicity were evaluated. It was found that the CS-HNP degrade by autoclaving and that sugars have no protective effect. Concerning gamma irradiation, the formation of agglomerates was observed, compromising the suspension stability. However, the nanoparticles resistance increases considerably in the presence of the sugars. Ozone sterilization did not lead to significant physical adverse effects, however, slight toxicity signs were observed, contrarily to gamma irradiation where no detectable changes on cells were found. Ozonation in the presence of sugars avoided cytotoxicity. Nevertheless, some chemical alterations were observed in the nanoparticles.info:eu-repo/semantics/publishedVersio

Socio-economy of peri-urban areas: the case of Lisbon metropolitan area

The chapter presents typologies of peri-urban areas of Lisbon Metropolitan Area (LMA) regarding social and economic dimensions. These typologies are the outcome of a trans-disciplinary research developed by the project PERI-URBAN involving different Portuguese universities, crossing academic fi elds and integrating the knowledge of stakeholders from diverse institutional and territorial (local and regional) backgrounds. By bridging science and society, transdisciplinarity allows the translation of knowledge acquired in research into useful and relevant information for planners and decision-makers. The analysis reveals diverse socioeconomic realities demanding different and specifi c political approaches envisaging sustainable peri-urban territories in a changing world. The socioeconomy of peri-urban areas considers identities and lifestyle issues (e.g., age, family patterns, living and working conditions) and economic characteristics (e.g., main economic activities, economic organisation and structuring, attractiveness). The infl uence of a metropolitan area is expressed by continuing investments in peripheral areas that offer sources of labour and natural resources such as land. The presence of industries, services, logistics and distribution platforms, enterprises, housing, big store chains, etc., constitutes manifestations of this realm. Plus, and in parallel, the coexistence of a rural-agriculture matrix establishes a hybrid territory where distinct activities co-exist defi ning distinct degrees of specialisation/diversity of the economic tissueinfo:eu-repo/semantics/publishedVersio

Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent mytilid fatty acids by ¹³C-fingerprinting

Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part oftheir energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assesstheir ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S), CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively). 14:0; 15:0; 16:0; 16:1(n - 7)c+t; 18:1(n - 13)c+t and (n - 7)c+t; 20:1(n - 7); 20:2(n - 9,15); 18:3(n - 7) and (n - 5,10,13) PLFA were labeled in the presence of H13CO3- (+H2S) and 13CH4, while the 12:0 compound became labeled only in the presence ofH13CO3- (+H2S). In contrast, the 17:0; 18:0; 16:1(n - 9); 16:1(n - 8) and (n - 6); 18:1(n - 8); and 18:2(n - 7) PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n - 7,15). Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts

Chemically crosslinked PVA hydrogels for cartilage substitution

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio