Concepciones de los estudiantes acerca de la gráfica de una función lineal de dominio discreto

Se reporta un estudio de casos realizado con estudiantes de 16-17 años en relación con sus concepciones sobre la gráfica de una función lineal de dominio discreto. En este estudio detectamos que los alumnos presentan dificultades en concebir la gráfica de una función cuando su dominio no es el conjunto de los números reales pues no consideran como gráficas de funciones a aquellas que sean un conjunto de “puntos” y que no formen una “línea continua”

O imaginário cristão nas novelas de cavalaria e nas cantigas de amor

Analisamos, neste texto, a influência da educação cristã no imaginário laico medieval, mais especificamente na novela A demanda do Santo Graal e nas cantigas de amor produzidas na Europa a partir do Século XII. Ao longo das nossas reflexões percebemos uma forte influência da Igreja tanto nas novelas de cavalaria quanto nas cantigas de amor, entretanto, tais influências não foram suficientemente fortes para evitar que a individualidade, substrato das tradições culturais anteriores ao Cristianismo, se desenvolvesse no imaginário medieval.We analyze, in this text, the influence of the christian education in the secular imaginary of the Middle Age, more exactly in the story of chivalry search for the Holy Grail and in the plaintive love songs, produced in the Europe in the twelfth century. Throughout the reflection, we observed an important influence of the Church as much in the cavalry stories as in the plaintive love songs, but these influences weren't sufficient for to avoid the increase, in the imaginary of Middle Age, of the individuality, cultural substratum of the Europe anterior the Christianism

Sobre la enseñanza de la geometría: re-creando el arco capaz

Se reporta una investigación realizada con alumnos de 15- 16 años sobre los algoritmos de construcción de un Arco Capaz de segmento y ángulo dado. Se propuso a los alumnos un problema cuya solución óptima es un Arco Capaz de segmento y ángulo dado, y se les requirió luego que construyeran dicho arco utilizando regla, compás y semicírculo. Los alumnos idearon diversas construcciones para el Arco Capaz pero en ningún momento aparece la construcción tradicional de Euclides. Básicamente, la idea que usan los estudiantes para construir el Arco Capaz, es la de obtener un triángulo cualquiera tal que uno de sus ángulos sea el ángulo dado para luego determinar su circuncentro y trazar el Arco

PALAVRAS NOS MUROS/PAREDES:

In this paper I propose a reflection about phrases and / or words scattered on the walls of the city of Araguaína (TO), problematizing issues such as eroticism, body, public and private. Its corpus includes the photographic records made by this author. To support the proposal, I refer to the following thinkers: Petit (2009); Arendt (2016); Foucault (1984); Bataille (2016); Gil (1997) and Certeau (2014). I venture to consider the potentialities of the writing / reading of walls as a place of mobilizing forces in which the body (intersubjectivities) is spoken, relating it to the dynamics of visibility / invisibility, to symbolize places of deviations and subversions.Neste trabalho proponho uma reflexão acerca de frases e/ou palavras espalhadas pelos muros da cidade de Araguaína (TO), problematizando questões como o erotismo, o corpo, o público e o privado. Seu corpus compreende os registros fotográficos feitos por esta autora. Para subsidiar a proposta, recorro aos seguintes pensadores: Petit (2009); Arendt (2016); Foucault (1984); Bataille (2016); Gil (1997) e Certeau (2014). Arrisco considerar as potencialidades da escrita/leitura dos muros/paredes como um lugar de forças mobilizadoras no qual se faz falar o corpo (as intersubjetividades), relacionando-o com as dinâmicas de visibilidade/invisibilidade, para simbolizar lugares de desvios e subversões

Environmental aspects of internal migration in Tanzania

In recent years, the issue of the nexus of climate change and human migration has attracted a growing amount of interest among scholars and policy makers. Using individual-level data from the Tanzania National Panel Survey conducted in 2008\u20132009, we examine the roles played by droughts or floods, crop diseases, and severe water shortages in inter-district migration in Tanzania. Findings reveal that droughts or floods and crop diseases are associated with an overall decrease in the likelihood of inter-district mobility, providing support for the \u201cenvironmental scarcity\u201d hypothesis. Yet migration becomes a likely response to droughts and floods among individuals with no education suggesting mobility is a key livelihood strategy among those most disadvantaged. Future examination of domestic migration-environment processes at the individual-level is critical for informed policy and programs

Urodynamic effects of oxybutynin and tolterodine in conscious and anesthetized rats under different cystometrographic conditions

BACKGROUND: Antimuscarinic agents are the most popular treatment for overactive bladder and their efficacy in man is well documented, producing decreased urinary frequency and an increase in bladder capacity. During cystometry in rats, however, the main effect reported after acute treatment with antimuscarinics is a decrease in peak micturition pressure together with little or no effect on bladder capacity. In the present experiments we studied the effects, in rats, of the two most widely used antimuscarinic drugs, namely oxybutynin and tolterodine, utilising several different cystometrographic conditions. The aim was to determine the experimental conditions required to reproduce the clinical pharmacological effects of antimuscarinic agents, as seen in humans, in particular their ability to increase bladder capacity. RESULTS: Intravenous or oral administration of tolterodine or oxybutynin in conscious rats utilized 1 day after catheter implantation and with saline infusion at constant rate of 0.1 ml/min, gave a dose-dependent decrease of micturition pressure (MP) with no significant change in bladder volume capacity (BVC). When the saline infusion rate into the bladder was decreased to 0.025 ml/min, the effect of oral oxybutynin was similar to that obtained with the higher infusion rate. Also, experiments were performed in rats in which bladders were infused with suramin (3 and 10 μM) in order to block the non-adrenergic, non-cholinergic component of bladder contraction. Under these conditions, oral administration of oxybutynin significantly reduced MP (as observed previously), but again BVC was not significantly changed. In conscious rats with bladders infused with diluted acetic acid, both tolterodine and oxybutynin administered at the same doses as in animals infused with saline, reduced MP, although the reduction appeared less marked, with no effect on BVC. In conscious rats utilized 5 days after catheter implantation, a situation where inflammation due to surgery is reduced, the effect of tolterodine (i.v.) and oxybutynin (p.o.) on MP was smaller and similar, respectively, to that observed in rats utilized 1 day after catheter implantation, but the increase of BVC was not statistically significant. In anesthetized rats, i.v. administration of oxybutynin again induced a significant decrease in MP, although it was of questionable relevance. Both BVC and threshold pressure were not significantly reduced. The number and amplitude of high frequency oscillations in MP were unmodified by treatment. Finally, in conscious obstructed rats, intravenous oxybutynin did not modify frequency and amplitude of non-voiding contractions or bladder capacity and micturition volume. CONCLUSION: Despite the different experimental conditions used, the only effect on cystometrographic parameters of oxybutynin and tolterodine in anesthetized and conscious rats was a decrease in MP, whereas BVC was hardly and non-significantly affected. Therefore, it is difficult to reproduce in rats the cystometrographic increase in BVC as observed in humans after chronic administration of antimuscarinic agents, whereas the acute effects seem more similar

Chronic heart failure is characterized by altered mitochondrial function and structure in circulating leucocytes

Oxidative stress is currently viewed as a key factor in the genesis and progression of Heart Failure (HF). The aim of this study was to characterize the mitochondrial changes linked to oxidative stress generation in circulating peripheral blood mononuclear cells isolated from chronic HF patients (HF_PBMCs) in order to highlight the involvement of mitochondrial dysfunction in the pathophysiology of HF. To assess the production of reactive oxygen species (ROS), mitochondrial function and ultrastructure and the mitophagic flux in circulating PBMCs we enrolled 15 patients with HF and a control group of ten healthy subjects. The HF_PBMCs showed a mitochondrial population consisting of damaged and less functional organelles responsible of higher superoxide anion production both at baseline and under in vitro stress conditions, with evidence of cellular apoptosis. Although the mitophagic flux at baseline was enhanced in HF_PBMCs at level similar to those that could be achieved in control PBMCs only under inflammatory stress conditions, the activation of mitophagy was unable to preserve a proper mitochondrial dynamics upon stress stimuli in HF. In summary, circulating HF_PBMCs show structural and functional derangements of mitochondria with overproduction of reactive oxidant species. This mitochondrial failure sustains a leucocyte dysfunctional status in the blood that may contribute to development and persistence of stress conditions within the cardiovascular system in HF