Citizens for Peace Minutes 1-11-11

This article presents data from a research that aims to show how mobilizations of mathematical knowledge occur when solving Physics tasks, considering the records of semiotic representation. To demonstrate the above, we present a qualitative analysis focused on the transformability of the records of semiotic representation of three tasks that were part of one of the instruments used in field research, as well as a summary explaining what they meant by Duval records of semiotic representation. In the end we present some considerations that point to the difficulties students may run into at the time of solving Physics tasks, which are somehow associated with the transformation of a record of semiotic representation

Resin Bonding to Silicatized Zirconia with Two Isocyanatosilanes and a Cross-linking Silane. Part II: Mechanistic Approach

In this paper we discuss and interpret the results of shear bond strengths achieved after the use of two silane coupling agents with isocyanato functionality, viz. 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. The silanes were used alone and also blended with a non-functional cross-linking silane on silicatized zirconia before light-curing of resin stubs on the surface, as described elsewhere in the first part of our study (see "Part I: Experimental"). A series of reaction mechanisms and conceptual diagrams are also presented. The reaction mechanisms illustrating the effect of adding a cross-linking silane into a silane blend, the silane hydrolysis and the behavior of two organofunctional groups (isocyanate and alkene) of silanes upon reaction with Rely X Unicem Aplicap resin-composite cement are discussed in detail. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 31 May 201

Three-dimensional culture of single embryonic stem-derived neural/stem progenitor cells in fibrin hydrogels: neuronal network formation and matrix remodelling

In an attempt to improve the efficacy of neural stem/progenitor cell (NSPC) based therapies, fibrin hydrogels are being explored to provide a favourable microenvironment for cell survival and differentiation following transplantation. In the present work, the ability of fibrin to support the survival, proliferation, and neuronal differentiation of NSPCs derived from embryonic stem (ES) cells under monolayer culture was explored. Single mouse ES-NSPCs were cultured within fibrin (fibrinogen concentration: 6 mg/ml) under neuronal differentiation conditions up to 14 days. The ES-NSPCs retained high cell viability and proliferated within small-sized spheroids. Neuronal differentiation was confirmed by an increase in the levels of ßIII-tubulin and NF200 over time. At day 14, cell-matrix constructs mainly comprised NSPCs and neurons (46.5% ßIII-tubulin + cells). Gamma-aminobutyric acid (GABA)ergic and dopaminergic/noradrenergic neurons were also observed, along with a network of synaptic proteins. The ES-NSPCs expressed matriptase and secreted MMP-2/9, with MMP-2 activity increasing along time. Fibronectin, laminin and collagen type IV deposition was also detected. Fibrin gels prepared with higher fibrinogen concentrations (8/10 mg/ml) were less permissive to neurite extension and neuronal differentiation, possibly owing to their smaller pore area and higher rigidity. Overall, it is shown that ES-NSPCs within fibrin are able to establish neuronal networks and to remodel fibrin through MMP secretion and extracellular matrix (ECM) deposition. This three-dimensional (3D) culture system was also shown to support cell viability, neuronal differentiation and ECM deposition of human ES-NSPCs. The settled 3D platform is expected to constitute a valuable tool to develop fibrin-based hydrogels for ES-NSPC delivery into the injured central nervous system.The authors would like to acknowledge Prof. Domingos Henrique (Instituto de Medicina Molecular, Lisbon) for providing the ES 46C cell line. This work was supported by FEDER funds through the Programa Operacional Factores de Competitividade – COMPETE (FCOMP‐01–0124‐FEDER‐021125) and by National funds FCT – Fundação para a Ciência e a Tecnologia (PTDC/SAU‐BMA/118869/2010). A.R.B. and M.J. Oliveira are supported by FCT (SFRH/BD/86200/2012; Investigator FCT)

A formação para ensinar matemática oferecida no curso normal de São Paulo e as influências que orientavam a direção desse curso ao longo dos primeiros anos de sua existência

Este artigo, resultado de pesquisa realizada, tem como finalidade identificar como o Curso Normal de São Paulo, desde sua criação até a década de 1930 formou professores para atuar no período de escolarização que hoje se denomina anos iniciais do Ensino Fundamental. Por meio de uma análise documental discute como se dava a preparação para ensinar Matemática, buscando indícios das influências que orientavam a direção desse curso durante os primeiros anos de sua existência. Foram analisados documentos elaborados por órgãos normativos e instituições formadoras, manuais didáticos e revistas destinadas ao ensino e à formação do professor. A pesquisa evidenciou, no Período do Império, o predomínio de uma formação genérica, assentada nos fundamentos da moral e bons costumes, o aumento da quantidade de disciplinas sob a influência do positivismo na época da Proclamação da República, e o foco nos Fundamentos da Educação e a influência da Psicologia a partir de 1920.  Palavras chave: Formação de professores. Conhecimentos matemáticos. Curso norma

Teorias da didática da matemática e o ensino de física

Este artigo pretende apresentar nossa pesquisa de Doutorado, pesquisa esta que teve por objetivo investigar as potencialidades e as limitações que o domínio de conhecimentos matemáticos, aliado a transformabilidade dos registros de representação semiótica gera para a aprendizagem de Física. A coleta de dados obedeceu a um método misto, em uma primeira etapa quantitativa elaboramos o panorama da formação de professores que ensinam Física no Ensino Médio no Brasil e uma segunda etapa da pesquisa qualitativa para análise da pesquisa de campo. Os resultados revelam dificuldades de mobilização de conteúdos matemáticos na resolução de tarefas de Física e que grande parcela dos professores que ministram a disciplina de Física no Ensino Médio não tem formação adequada para tal

Genome-wide association and HLA fine-mapping studies identify risk loci and genetic pathways underlying allergic rhinitis

Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis

Fibrin functionalization with synthetic adhesive ligands interacting with a6ß1 integrin receptor enhance neurite outgrowth of embryonic stem cell-derived neural stem/progenitors

To enhance fibrin hydrogel affinity towards pluripotent stem cell-derived neural stem/progenitor cells (NSPCs) and its capacity to support NSPC migration and neurite extension, we explored the tethering of synthetic peptides engaging integrin a6ß1, a cell receptor enriched in NSPCs. Six a6ß1 integrin ligands were tested for their ability to support integrin a6ß1-mediated adhesion of embryonic stem cell-derived NSPCs (ES-NSPs) and sustain ES-NSPC viability, migration, and neuronal differentiation. Due to their better performance, peptides T1, HYD1, and A5G81 were immobilized into fibrin and functionalized gels characterized in terms of peptide binding efficiency, structure and viscoelastic properties. Tethering of T1 or HYD1 successfully enhanced cell outgrowth from ES-NSPC neurospheres (up to 2.4-fold increase), which exhibited a biphasic response to peptide concentration. Inhibition assays evidenced the involvement of a6ß1 and a3ß1 integrins in mediating radial outgrowth on T1-/HYD1-functionalized gels. Fibrin functionalization also promoted neurite extension of single ES-NSPCs in fibrin, without affecting cell proliferation and neuronal differentiation. Finally, HYD1-functionalized gels were found to provide a permissive environment for axonal regeneration, leading up to a 2.0-fold increase in neurite extension from rat dorsal root ganglia explants as compared to unmodified fibrin, and to significant improved locomotor function after spinal cord injury (complete transection), along with a trend toward a higher area positive for growth associated protein 43 (marker for axonal growth cone formation). Our results suggest that conjugation of a6ß1 integrin-binding motifs is of interest to increase the biofunctionality of hydrogels used in 3D platforms for ES-NSPC culture and potentially, in matrix-assisted ES-NSPC transplantation. Statement of Significance Impact statement: The transplantation of NSPCs derived from pluripotent stem cells holds much promise for the treatment of central nervous system disorders. Moreover, the combinatorial use of biodegradable hydrogels with NSPCs was shown to contribute to the establishment of a more permissive environment for survival and integration of transplanted cells. In this study, fibrin hydrogels functionalized with a synthetic peptide engaging integrin a6ß1 (HYD1) were shown to promote neurite extension of ES-NSPCs, which is fundamental for the formation of functional neuronal relay circuits after NSPC transplantation. Notably, HYD1-functionalized fibrin per se led to enhanced axonal growth ex vivo and to an improvement in locomotor function after implantation in a rat model of spinal cord injury. Conjugation of a6ß1 integrin-binding motifs may therefore be of interest to confer bioactivity to NSPC hydrogel vehicles.The authors would like to acknowledge Prof. Domingos Henrique (Instituto de Medicina Molecular, Lisbon) for providing theES 46C cell line. This work was supported by FEDER funds throughthe Programa Operacional Factores de Competitividade – COMPETE(FCOMP-01-0124-FEDER-021125) and by National Funds throughFCT – Fundação para a Ciência e a Tecnologia (PTDC/SAU-BMA/118869/2010). A.R.B. and D.B. are supported by FCT (SFRH/BD/86200/2012; PD/BD/105953/2014)

Identification of critical paralog groups with indispensable roles in the regulation of signaling flow

Extensive cross-talk between signaling pathways is required to integrate the myriad of extracellular signal combinations at the cellular level. Gene duplication events may lead to the emergence of novel functions, leaving groups of similar genes - termed paralogs - in the genome. To distinguish critical paralog groups (CPGs) from other paralogs in human signaling networks, we developed a signaling network-based method using cross-talk annotation and tissue-specific signaling flow analysis. 75 CPGs were found with higher degree, betweenness centrality, closeness, and ‘bowtieness’ when compared to other paralogs or other proteins in the signaling network. CPGs had higher diversity in all these measures, with more varied biological functions and more specific post-transcriptional regulation than non-critical paralog groups (non-CPG). Using TGF-beta, Notch and MAPK pathways as examples, SMAD2/3, NOTCH1/2/3 and MEK3/6-p38 CPGs were found to regulate the signaling flow of their respective pathways. Additionally, CPGs showed a higher mutation rate in both inherited diseases and cancer, and were enriched in drug targets. In conclusion, the results revealed two distinct types of paralog groups in the signaling network: CPGs and non-CPGs. Thus highlighting the importance of CPGs as compared to non-CPGs in drug discovery and disease pathogenesis

Challenge clusters facing LCA in environmental decision-making—what we can learn from biofuels

Purpose Bioenergy is increasingly used to help meet greenhouse gas (GHG) and renewable energy targets. However, bioenergy’s sustainability has been questioned, resulting in increasing use of life cycle assessment (LCA). Bioenergy systems are global and complex, and market forces can result in significant changes, relevant to LCA and policy. The goal of this paper is to illustrate the complexities associated with LCA, with particular focus on bioenergy and associated policy development, so that its use can more effectively inform policymakers. Methods The review is based on the results from a series of workshops focused on bioenergy life cycle assessment. Expert submissions were compiled and categorized within the first two workshops. Over 100 issues emerged. Accounting for redundancies and close similarities in the list, this reduced to around 60 challenges, many of which are deeply interrelated. Some of these issues were then explored further at a policyfacing workshop in London, UK. The authors applied a rigorous approach to categorize the challenges identified to be at the intersection of biofuels/bioenergy LCA and policy. Results and discussion The credibility of LCA is core to its use in policy. Even LCAs that comply with ISO standards and policy and regulatory instruments leave a great deal of scope for interpretation and flexibility. Within the bioenergy sector, this has led to frustration and at times a lack of obvious direction. This paper identifies the main challenge clusters: overarching issues, application and practice and value and ethical judgments. Many of these are reflective of the transition from application of LCA to assess individual products or systems to the wider approach that is becoming more common. Uncertainty in impact assessment strongly influences planning and compliance due to challenges in assigning accountability, and communicating the inherent complexity and uncertainty within bioenergy is becoming of greater importance. Conclusions The emergence of LCA in bioenergy governance is particularly significant because other sectors are likely to transition to similar governance models. LCA is being stretched to accommodate complex and broad policy-relevant questions, seeking to incorporate externalities that have major implications for long-term sustainability. As policy increasingly relies on LCA, the strains placed on the methodology are becoming both clearer and impedimentary. The implications for energy policy, and in particular bioenergy, are large