1,256 research outputs found

    An encounter between Paulo Freire and mathematics education: Maria do Carmo Domite instigated by Régis Forner

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    A professora Maria do Carmo Santos Domite conta ao mestrando da educação matemática Régis Forner sua vivência junto ao educador Paulo Freire –um dos maiores ícones da educação brasileira– em especial, durante sua gestão na Secretaria Municipal de Educação de São Paulo. De modo geral, Domite coloca sua reflexão na busca de Freire em situar a ação educativa na cultura do educando, no sentido de considerar/respeitar a cultura que cada um traz dentro de si –finalidades que uma professora e um professor que vêem a educação como uma prática libertadora devem perseguir. Paulo Freire publicou mais de 30 obras. A mais famosa Pedagogia do Oprimido foi publicada primeiramente em inglês em 1970 e, no Brasil, somente em 1974, hoje na 50ª edição. Freire foi exilado político de 1964 a 1980, residiu em vários países onde também contribuiu para a discussão das políticas educacionais locais. Domite, professora da Faculdade de Educação da Universidade de São Paulo, vem desenvolvendo seus estudos e pesquisas em Etnomatemática sempre considerando o potencial de levar em conta a cultura dos educandos nos processos educacionais. Esta entrevista surge de uma ramificação da dissertação de mestrado de Régis Forner (Pontifícia Universidade Católica de Campinas), no qual ele buscava estabelecer as relações e influências das ideias e teorizações de Paulo Freire na Educação MatemáticaEn este documento la profesora Maria do Carmo Santos Domite entrevista al estudiante de Máster en Educación Matemática, Régis Forner, sobre las experiencias que vivió junto a uno de los mayores iconos de la educación brasileña, Paulo Freire, en especial, durante su permanencia en la Secretaría Municipal de Educación de São Paulo. Domite reflexiona en torno a la intención de Freire de situar la acción educativa en la cultura de los estudiantes, es decir, considerando y respetando la cultura que cada estudiante trae consigo y entendiendo que la meta de la Educación es perseguir la práctica de la libertad. Paulo Freire publicó más de 30 obras literarias. La más famosa es la Pedagogía del Oprimido, publicada inicialmente en Inglés en 1970, más tarde puesta a libre disposición en Brasil en 1974, y que actualmente se encuentra en su 50ª edición. Paulo Freire, exiliado entre 1964 y 1980, vivió en varios países desde donde también contribuyó al diálogo y el desarrollo de las políticas educativas locales. La profesora Domite ha llevado a cabo estudios e investigaciones en Etnomatemáticas, siempre preocupada por entender el potencial que significa considerar la cultura de los estudiantes en los procesos educativos. Esta entrevista surge de una ramificación de la tesis de Régis Forner (PUC-Campinas, en São Paulo), en la que Régis trató de establecer la relación y la influencia de las ideas y las teorías de Paulo Freire en la Educación MatemáticaProfessor Maria do Carmo Santos Domite talks to the mathematics education master student Régis Forner about her experiences along with Paulo Freire –one of the most note-worthy personalities in the history of Brazilian education– especially, while his tenure at the São Paulo Municipal Secretary of Education. In general, Domite places her reflection on Freire’s search in locating the educational action in the student's culture, that is, considering and respecting the culture that each student brings inside themselves – goals that a teacher who see education as a practice of freedom should pursue. Paulo Freire published more than 30 literary works. The most famous one is the Pedagogy of the Oppressed, initially published in English in 1970, later released in Brazil only in 1974 and it is currently in its 50th edition. Exiled between 1964 and 1980, Paulo Freire lived in several countries where he also contributed to the dialogue and development of the local educational policies. Domite, Professor of Education of the University of São Paulo has been developing her studies and researches in Ethnomathematics, always concerned about understanding the potential of taking in account the culture of the students in educational processes. This interview emerges from one ramification of the thesis of Régis Forner (PUC-Campinas in São Paulo State), in which Régis sought to establish the relationship and influence of ideas and theorizations from Paulo Freire in Mathematics Educatio

    Podoconiosis in Ethiopia. A pilot study to improve the management of Lymphedema.

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    Podoconiosis is a non-infectious cause of lymphedema, frequent in Africa. The aim of this study is to implement the management of lymphedema secondary to podoconiosis in a rural hospital in Southern Ethiopia. A call for donation of compression garments was made in Spain, to give any used and retired garment among lymphedema patients. The working plan was to train the staff in the lymphatic system, the causes of lymphedema, prevention strategies, skin care, intensive treatment and maintenance at long-term, Decongestive lymphatic treatment of the patients affected from podoconiosis and the adaptation of the donated garments for maintenance phase. Fifteen patients were treated with 10 sessions of Decongestive Lymphatic Therapy (DLT) consisting of Manual Lymphatic Drainage and multilayer bandages. The Percentage of Volume Reduction was 11.3% (95%CI: 8.8-13.9). Fifty percent of the patients showed an increase of the volume of lymphedema as they did not comply with the compression treatment. This pilot study has had good results in helping lymphedema management in Southern Ethiopia. The donation of used garments by chronic patients can be a feasible and effective step to improving the maintenance phase of patients with lymphedema in places with limited resources

    From Davydov solitons to decoherence-free subspaces: self-consistent propagation of coherent-product states

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    The self-consistent propagation of generalized D1D_{1} [coherent-product] states and of a class of gaussian density matrix generalizations is examined, at both zero and finite-temperature, for arbitrary interactions between the localized lattice (electronic or vibronic) excitations and the phonon modes. It is shown that in all legitimate cases, the evolution of D1D_{1} states reduces to the disentangled evolution of the component D2D_{2} states. The self-consistency conditions for the latter amount to conditions for decoherence-free propagation, which complement the D2D_{2} Davydov soliton equations in such a way as to lift the nonlinearity of the evolution for the on-site degrees of freedom. Although it cannot support Davydov solitons, the coherent-product ansatz does provide a wide class of exact density-matrix solutions for the joint evolution of the lattice and phonon bath in compatible systems. Included are solutions for initial states given as a product of a [largely arbitrary] lattice state and a thermal equilibrium state of the phonons. It is also shown that external pumping can produce self-consistent Frohlich-like effects. A few sample cases of coherent, albeit not solitonic, propagation are briefly discussed.Comment: revtex3, latex2e; 22 pages, no figs.; to appear in Phys.Rev.E (Nov.2001

    The noise performance of a high-speed capacitive-sensor interface based on a relaxation oscillator and a fast counter

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    This paper presents the analysis and experimental results on the noise performances of a capacitive-sensor interface. The interface is able to measure low capacitance values in the order of picofarads and is implemented with a simple relaxation oscillator, a fast counter, and a microcontroller. The goal is to find the criteria to implement a low-noise system, so that, even with a short measuring time, low noise can be obtained. Experimental results are performed in order to prove the validity of the theoretical analysis. The achieved resolution, with a measuring time of 20 ms, was better than 14.2 /spl times/ 10/sup -7/ for the measurement of a capacitance value of 2.2 pF.Peer Reviewe

    Exploring the role of electrode microstructure on the performance of non-aqueous redox flow batteries

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    Redox flow batteries are an emerging technology for long-duration grid energy storage, but further cost reductions are needed to accelerate adoption. Improving electrode performance within the electrochemical stack offers a pathway to reduced system cost through decreased resistance and increased power density. To date, most research efforts have focused on modifying the surface chemistry of carbon electrodes to enhance reaction kinetics, electrochemically active surface area, and wettability. Less attention has been given to electrode microstructure, which has a significant impact on reactant distribution and pressure drop within the flow cell. Here, drawing from commonly used carbon-based diffusion media (paper, felt, cloth), we systematically investigate the influence of electrode microstructure on electrochemical performance. We employ a range of techniques to characterize the microstructure, pressure drop, and electrochemically active surface area in combination with in-operando diagnostics performed in a single electrolyte flow cell using a kinetically facile redox couple dissolved in a non-aqueous electrolyte. Of the materials tested, the cloth electrode shows the best performance; the highest current density at a set overpotential accompanied by the lowest hydraulic resistance. We hypothesize that the bimodal pore size distribution and periodic, well-defined microstructure of the cloth are key to lowering mass transport resistance

    Production of n-propyl acetate by reactive distillation : experimental and theoretical study

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    First steps of the development of a catalytic reactive distillation process for the production of n-propyl acetate based on experiments and simulations are proposed. The kinetics for homogeneously (sulphuric acid) and heterogeneously (Amberlyst 15) catalysed reaction were investigated and the constants for a pseudo-homogeneous model are presented. Pilot plant experiments were performed using a homogeneous strong acid catalyst in a packed column. A top-column decanter is used to withdraw the aqueous phase and to reflux the organic phase. Simulation results are in good agreement with experimental data. Thermodynamics nonidealities are taken into account using VLE and LLE NRTL interaction parameters. Alcohol conversion and n-propyl acetate purity may be dramatically increased just by adding to the pilot plant a stripping section in an additional column: six different configurations are identified to achieve such a production. The startup is studied in order to determine the best strategy to achieve steady-state conditions. The strong influence of the composition of the initial charging in the decanter can be seen and an initial charging of the two-phase top product leads to the fastest startup

    The floating capacitor as a differential building block

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    This paper analyzes the advantages and limitations of using the floating- (or flying-) capacitor technique as a building block with differential input and either differential or single-ended output to implement voltage amplifiers, multiplexers, and coherent amplitude demodulators. Theoretical analysis, supported by experimental results, shows that the fully differential configuration has a better common-mode rejection ratio (CMRR). However, if the output signal, once amplified, must be single ended, then it may be better to have a floating capacitor with single-ended output in amplifiers and some multiplexers whereas in demodulators a floating capacitor with differential output yields a better CMRR.Peer Reviewe

    Subsurface resistivity measurements using square waveforms

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    This work analyzes the effect of inductive and capacitive coupling between the injecting circuit and the detecting circuit in resistive field surveys. Theoretical and experimental results demonstrate that if a square waveform is injected into the soil, and synchronous sampling is used to sample at the flat zone of the detected voltage, then the effect of the interference is greatly reduced. Furthermore, square waveforms are easier to generate than sinusoidal waveforms, so they offer a new approach to subsurface resistivity measurements.Peer Reviewe

    Predictors of turnover amongst volunteers:A systematic review and meta‐analysis

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    Volunteers represent a global workforce equivalent to 61 million full-time workers. A significant decline in volunteering has highlighted the urgency to better understand and address turnover amongst volunteers. To address this, we conducted a systematic review and meta-analysis of turnover amongst volunteers. We also examined whether staying or leaving has different predictors. The meta-analysis integrated and synthesized 117 studies, encompassing 1104 effect sizes across 55 335 volunteer workers, to identify and quantify relationships between turnover and the broad range of variables that have been examined in the volunteer work domain. Amongst the strongest predictors of volunteer turnover were attitudinal variables, in particular, job satisfaction (ρ = −.58), affective commitment (ρ = −.58), engagement (ρ = −.54) and organizational commitment (ρ = −.54). Contextual variables that showed the largest effects included communication (ρ =.62), organizational support (ρ = −.61) and the quality of the relationship between volunteers and their leader (leader-member exchange, ρ = −.55). We synthesize our findings into an integrative framework delineating the predictors of volunteer turnover. In doing so, we extend turnover research to consider non-remunerated work contexts and provide a basis for developing turnover theory that is responsive to the unique experience of volunteers.</p
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