Mathematics in the middle: The relationship between measurement and metamorphic matter

This paper revisits philosophical questions regarding the relationship between mathematics and matter. I briefly present four contrary and contemporary perspectives on the speculative force of mathematics, as a provocation for further discussion on the subject of sciento-metrics. I first consider the ideas of the philosopher Quentin Meillassoux, as a way of setting the stage for various kinds of materialist philosophies of mathematics. I then turn to the ideas of two mathematicians - Fernando Zalamea and Giuseppe Longo - and a computer scientist - Gregory Chaitin - and explore how their discussions of contemporary mathematical practice offer important insight (and twist) regarding the relationship between mathematics and matter

THE DIASPORA SENSIBILITY IN TEACHER IDENTITY: LOCATING SELF THROUGH STORY

The concept of diaspora describes the dispersal of persons from their traditional homeland, across national and cultural borders. We explore disasporic (dis)location as it disrupts and recreates teacher identity. The nomadic movement across borders in professional development is best understood through narrative; hence we examine the self‐constructed narratives of three participants in a graduate class representing diverse cultural backgrounds who traced their complex and shifting teacher stories as a construct to understand the complex shifts in their identities. In a rapidly changing global migration, these narratives provide insight into the navigations and negotiations of diasporic journeys and shifting, evolving perceptions of teacher identities. Key words: teacher learning, narrative as heuristic, dialogic, transnational migration, transnational dislocation Le concept de diaspora évoque la dispersion des personnes loin de leur pays d’origine et le franchissement de frontières nationales et culturelles. Les auteures explorent la dislocation de la diaspora et son lien avec la rupture et la recréation de l’identité d’enseignant. Le nomadisme au‐delà des frontières dans le perfectionnement professionnel se comprend mieux à travers des récits ; les auteures examinent donc les comptes rendus personnels de trois participants dans un cours du second cycle universitaire. Venus d’horizons culturels différents, ces participants relatent leurs histoires complexes sous le signe du changement comme un construit visant à élucider la transformation de leurs identités. Compte tenu de l’évolution rapide et complexe de la migration à l’échelle internationale, ces récits permettent de mieux saisir les navigations et négociations des périples de la diaspora et l’évolution des perceptions des identités des enseignants.Mots clés : apprentissage chez les enseignants, récit et migration heuristique, dialogique et transnationale, dislocation transnationale.

(Dis)orientation and spatial sense: Topological thinking in the middle grades

In this paper, we focus on topological approaches to space and we argue that experiences with topology allow middle school students to develop a more robust understanding of orientation and dimension. We frame our argument in terms of the phenomenological literature on perception and corporeal space. We discuss findings from a quasi-experimental study engaging 9 grades 5-8 students (10-13 years old) in a 6-week series of school-based workshops focused on knot theory. We discuss video data that shows how students engage with the intrinsic disorientation of mathematical knots through the use of gesture and movement.(Des)orientación y sentido espacial: pensamiento topológico en los grados intermediosEn este trabajo, nos centramos en enfoques topológicos del espacio y sostenemos que las experiencias con topología permiten a los estudiantes de secundaria desarrollar una comprensión más sólida de la orientación y de la dimensión. Enmarcamos nuestro argumento en términos de la literatura fenomenológica de la percepción y el espacio corpóreo. Discutimos los hallazgos de un estudio cuasi-experimental con 9 estudiantes de quinto a octavo curso (10 a 13 años) que participaron en talleres sobre la teoría de nudos durante 6 semanas. Discutimos los datos de vídeo que muestran cómo los estudiantes se involucran con la desorientación intrínseca de los nudos matemáticos mediante el uso del gesto y movimiento.Handle: http://hdl.handle.net/10481/3323

(Des)orientación y sentido espacial: pensamiento topológico en los grados intermedios

This document was originally published as Freitas, E.& McCarthy, MJ. (2013).(Dis)Orientation and spatial sense: Topological thinking in the middle grades. In B. Ubuz, Ç. Haser, & M. A. Mariotti (Eds.), Proceedings of the Eighth Congress of European Research in Mathematics (pp. 615-624). Antalya, Turkey.In this paper, we focus on topological approaches to space and we argue that experiences with topology allow middle school students to develop a more robust understanding of orientation and dimension. We frame our argument in terms of the phenomenological literature on perception and corporeal space. We discuss findings from a quasi-experimental study engaging 9 grades 5-8 students (10-13 years old) in a 6-week series of school-based workshops focused on knot theory. We discuss video data that shows how students engage with the intrinsic disorientation of mathematical knots through the use of gesture and movement.En este trabajo, nos centramos en enfoques topológicos del espacio y sostenemos que las experiencias con topología permiten a los estudiantes de secundaria desarrollar una comprensión más sólida de la orientación y de la dimensión. Enmarcamos nuestro argumento en términos de la literatura fenomenológica de la percepción y el espacio corpóreo. Discutimos los hallazgos de un estudio cuasi-experimental con 9 estudiantes de quinto a octavo curso (10 a 13 años) que participaron en talleres sobre la teoría de nudos durante 6 semanas. Discutimos los datos de vídeo que muestran cómo los estudiantes se involucran con la desorientación intrínseca de los nudos matemáticos mediante el uso del gesto y movimiento

Science studies and the metamorphic multiple earth: Bruno Latour's risky diplomacy

This essay focuses on Bruno Latour’s recent attempts to study the metamorphic zone of terrestrial life, within the current climate crisis and environmental “cosmocolossus”. I explore his proposal for a risky diplomacy in the Anthropocene “end times”, as a way of dealing with the increasingly tense relations between polarized and weaponized perspectives. I show how his work continues to seek a form of scientific practice that involves the invention of equipment (apparatus) that make perceptible (principally to humans) the existence of non-human agencies, thereby expanding the opportunities for alliances and a pluralist ecology, and ultimately assembling another more-than-human political body. I also discuss critiques and concerns regarding the specifics of this proposal

Pre-service teachers using core philosophical questions to analyze mathematical behavior.

In this chapter, I discuss a course in the philosophy of mathematics designed to help future high school mathematics teachers develop an understanding of philosophical questions about mathematics. My aim was to equip these future teachers with philosophical skills for analyzing mathematical behavior. Teachers who can analyze their students’ mathematical activity for how concepts are at work can get beyond simple evaluative responses to students –typically assessing their performance as right or wrong –and can begin to explore theirstudents’ mathematical thinking. This is a difficult skill to develop, and philosophy offers one way of doing so. Philosophical questions about mathematics open up discussions about why we have the mathematics we have, inviting consideration of how mat hematics is embodied in particular material practice

A poetics of opacity : Towards a new ethics of participation in gallery-based art projects with young people

Peer reviewe

Molecular evolution and structural analyses of proteins involved in metabolic pathways of volatile organic compounds in Petunia hybrida (Solanaceae)

The association between plants and their pollinators is essential for increasing the diversity in angiosperms. Morphological and physiological traits, mainly floral scent, can influence the pollination dynamics and select pollinators for each plant species. In this work, we studied two proteins involved in producing volatile organic compounds in plants, conyferyl alcohol acyltransferase (CFAT) and benzoyl-CoA:benzyl alcohol/phenyl ethanol benzoyl transferase (BPBT) genes. We aimed to understand these proteins with respect to evolutionary and structural aspects and functions in Solanaceae using phylogenetic methods and comparative molecular modeling. We used Bayesian inference to describe the proteins’ evolutionary history using Petunia x hybrida as a query to search for homologs in the Solanaceae family. Theoretical 3D models were obtained for both proteins using Panicum virgatum as a template. The phylogenetic tree included several different enzymes with diverse biological roles in Solanaceae, displaying the transferase domain. We identified only one sequence of CFAT in the databases, which belongs to Petunia x hybrida, and found several BPBT sequences from the genera Nicotiana, Solanum, and Capsicum. The 3D structures of CFAT and BPBT have two different domains, and we have identified the amino acid residues essential for the enzymatic activity and interaction with substrates

Obtenção de um catalisador misto Fe2O3/TiO2 e seu uso em Processos Oxidativos Avançados

Advanced Oxidation Processes (AOP), applied to water and effluent treatment, are an efficient alternative for the removal of recalcitrant organic compounds. These processes are based on the generation and use of the hydroxyl radical ( • OH) which is a strong oxidizing agent. Among the AOP are solar photocatalysis and Fenton-type reactions, either homogeneous or heterogeneous. In this work was obtained a catalyst containing Fe2O3 /TiO2 in the proportion 80/20 (% by mass). The synthesis of the compound was performed using the Pechini method, with pyrolysis for 1h at 400 ° C and subsequent calcination at 400, 450 and 500 ° C for 2h. The samples calcined at different temperatures were characterized and evaluated for their use in solar photocatalysis and Fenton reactions for the degradation of the methylene blue dye. The preliminary tests showed that the samples did not show efficiency for solar photocatalysis when a concentration of 0.1 g / L of catalyst was used, being necessary the addition of hydrogen peroxide. Subsequently, tests involving Fenton-type reactions were performed with samples calcined at 400, 450 and 500 ° C. The sample calcineat 450 ° C showed better efficiency among the others calcination temperatures, since it presented a higher initial reaction rate and an increase in the percentage of color removal, being used for the other tests. The sample yielded an efficiency and degradation rate of the organic compound much higher than those obtained for the pure catalysts (Fe2O3 or TiO2), proving that there is a positive effect on the interaction between Fe and Ti, favorable to the Fenton reaction. From the analysis of the influence of hydrogen peroxide concentration on color removal, it was observed that approximately 100% dye removal was obtained, with the following ratio AM: H2O2: 50mg / L catalyst: 24mg / L: 0,1g/L. Assays evaluating the initial pH of the aqueous solution showed that the Fenton process operates over a broad pH range (3.0 to 9.0). Analyzing the influence of sunlight, it was observed that in the test performed in the absence of light, solar or artificial, a percentage of dye degradation was obtained of 79.2%, whereas in the test in the presence of sunlight this percentage was 96.5%. Comparative tests evaluated the dependence of the percentage of degradation obtained as a function of the average irradiation rate, which showed that, with an average irradiation of 3096.2 KJ / m2, it was possible to remove 98% of color, whereas, in the experiment performed under average irradiation of 4365.2 KJ / m2 it was obtaindes approximately 100% degradation. The catalyst reuse assay showed that in the first cycle, 98% color removal was achieved, whereas in the second cycle only 18% of the dye was degraded, which can be attributed to the fact that a portion of the iron present in the catalyst being leached into the solution. Therefore, the Fenton reaction has a homogeneous character, and a heterogeneous Fenton plot can also coexist.Os Processos de Oxidação Avançada (POAs), aplicados ao tratamento de águas e efluentes, são uma alternativa eficiente para a remoção de compostos orgânicos recalcitrantes. Estes processos se baseiam na geração e uso do radical hidroxila ( • OH) que é um forte agente oxidante. Dentre os POAs destacam-se a fotocatálise solar e as reações do tipo Fenton, seja homogêneo ou heterogêneo. Neste trabalho foi obtido um catalisador contendo Fe2O3/TiO2 na proporção 80/20 (% em massa). A síntese do composto foi realizada por meio do método Pechini, com pirólise por 1h a 400°C e posterior calcinação a 400, 450 e 500°C por 2h. As amostras calcinadas nas diferentes temperaturas foram caracterizadas e avaliadas quanto ao seu uso na fotocatálise solar e em reações do tipo Fenton para a degradação do corante azul de metileno. Os ensaios preliminares mostraram que as amostras não apresentaram eficiência para fotocatálise solar quando utilizada uma concentração de 0,1 g/L de catalisador, sendo necessária a adição de peróxido de hidrogênio. Posteriormente, testes envolvendo reações do tipo Fenton foram realizados com as amostras calcinadas a 400, 450 e 500°C. A amostra calcinada a 450°C mostrou melhor eficiência dentre as outras temperaturas de calcinação, uma vez que, apresentou maior velocidade inicial de reação e aumento na porcentagem de remoção de cor, sendo esta utilizada para os demais ensaios realizados. A amostra produzida apresentou eficiência e velocidade de degradação do composto orgânico muito superiores àquelas obtidas para os catalisadores puros (Fe2O3 ou TiO2), comprovando que há um efeito positivo na interação entre o Fe e o Ti, favorável a reação Fenton. A partir da análise da influência da concentração de peróxido de hidrogênio na remoção de cor, observou-se que foi obtida aproximadamente 100% de remoção do corante, com a seguinte relação AM:H2O2:catalisador de 50mg/L:24mg/L:0,1g/L. Ensaios avaliando o pH inicial da solução aquosa mostraram que o processo Fenton atua em uma ampla faixa de pH (3,0 a 9,0). Analisando a influência da luz solar observou-se que no ensaio realizado na ausência de luz, solar ou artificial, foi obtida uma porcentagem de degradação do corante de 79,2 %, enquanto que no ensaio na presença da luz solar esta porcentagem foi de 96,5%. Testes comparativos avaliaram a dependência da porcentagem de degradação obtida em função da taxa de irradiação média, estes mostraram que, com uma irradiação média de 3096,2 KJ/m2 foi possível remover 98% de cor, enquanto que, no ensaio realizado sob irradiação média de 4365,2 KJ/m2, obteve-se aproximadamente 100% de degradação. O ensaio de reuso do catalisador mostrou que no primeiro ciclo, 98% de remoção de cor foi alcançada, ao passo que, no segundo ciclo apenas 18% do corante foi degradado, o que pode ser atribuído ao fato de uma parcela do ferro presente no catalisador estar sendo lixiviado para a solução. Portanto, a reação Fenton apresenta caráter homogêneo, podendo coexistir também, uma parcela de Fenton hetero