Analysis of Nonlinear Noisy Integrate\&Fire Neuron Models: blow-up and steady states

Nonlinear Noisy Leaky Integrate and Fire (NNLIF) models for neurons networks can be written as Fokker-Planck-Kolmogorov equations on the probability density of neurons, the main parameters in the model being the connectivity of the network and the noise. We analyse several aspects of the NNLIF model: the number of steady states, a priori estimates, blow-up issues and convergence toward equilibrium in the linear case. In particular, for excitatory networks, blow-up always occurs for initial data concentrated close to the firing potential. These results show how critical is the balance between noise and excitatory/inhibitory interactions to the connectivity parameter

Diseño e implementación de una asignatura de formación de docentes reflexivos de matemáticas que considera los contenidos globalizados

La forma de percibir la enseñanza y aprendizaje de las matemáticas se ha ido modificando en los últimos años, lo que debe tener reflejo en la formación de los futuros docentes. En este sentido, se propone un diseño e implementación de una experiencia de formación de docentes de matemáticas que considera los contenidos globalizados, reconoce la reflexión como aspecto fundamental para formar profesionales capacitados para reflexionar sobre su práctica y mejorarla, y contempla la evaluación como instrumento formativo. La propuesta se basa en la confección de un Proyecto, al principio del curso, por parte de los estudiantes, en grupos de 2, que deben mejorar y entregar de nuevo al finalizar el mismo a partir de la formación recibida. Después de experimentarlo se descubrió, por ejemplo, que los futuros docentes estuvieron motivados y realizaron tareas interesantes

Italo Calvino: la escritura imaginaria

En este artículo se analiza el estilo de Italo Calvino, basado en su trilogía “I nostri antenati”, “Le Cosmicomiche” y “Ti con Zero”. El lenguaje de la ciencia ficción, romance, mito, apólogo y otros recursos en los que se basa son considerados como relevantes componentes estilísticos de su narrativa de fantasía. Finalmente, también se señala la diferencia entre la narrativa del siglo XX y los escritos de Italo Calvino.In this article mainly based on his trilogy “I nostri antenati”,” Le Cosmicomiche” and “Ti con Zero”, Italo Calvino's style is analysed. The language of science fiction, romance, myth, the apology and other literary sources, he draws on, are also considered as relevant stylistic components of his narrative of fantasy. Finally, the main differences between a nineteenth century narrative of fantasy and Calvino's writings are also pointed out

Caracterización de tareas matemáticas creadas por estudiantes para maestro a partir de contextos cotidianos

Los maestros deben ser capaces de crear tareas matemáticas en diversos sentidos para promover un pensamiento diverso y flexible en los alumnos, y esa capacidad se debería desarrollar en su formación inicial. Algunas tareas matemáticas interesantes son las abiertas y realistas, ya que desarrollan capacidades matemáticas aplicables a situaciones propias de la vida cotidiana, algo fundamental para dar sentido a las matemáticas de Primaria (Yeo, 2015). Tener en cuenta el tipo de procesos cognitivos que se activan en su resolución también es importante para los estudiantes de Primaria (OCDE, 2012)

El sentimiento de la soledad en la poesía de Cesare Pavese

La obra de Pavese presenta, en su conjunto, una trayectoria que va desde la búsqueda de una poesía narrativa y objetiva a una obra narrativa impregnada de datos autobiográficos, la subjetividad pavesiana. Apareciendo los sentimientos dolorosos, que durante tiempo intentó ocultar en su poesía: soledad, autodestrucción, amor y muerte.The article presents comments on Teocrito's work, demonstrating that current studies have given rise to a better understanding of their language and style. The new survey methodologies have resulted in the existence of a consistency between the texts themselves and between texts and their context.peerReviewe

Use and abuse of calculators: implications for mathematics education

Fostering mathematical understanding and sense for numbers is an objective for current mathematics education. This paper presents a historical vision of the use of numbers and of calculation processes and reflects about the current need of electronic calculators. The coexistence of two different mathematical systems, one based on the Greek axiomatic mathematics and another, the floating point system, used in electronic calculators, can lead to some confusions that which affects the teaching of mathematics, especially in the numerical sense development. The paper also presents common mistakes caused by the missing verification of the results from calculations or lack of awareness about the limitations of calculators. Finally, the implications those elements have on the mathematical education are presented together with some conclusions

EPTC in sugarcane (Saccharum spp. hybrids): incorporation methods, weed control, and crop tolerance

Research conducted over two years evaluated EPTC at 2.0, 2.9, 3.9, and 4.9 kg ai/ha incorporated on pre-formed sugarcane beds using a Lilliston® rolling cultivator and a hipper/bedder. Averaged across EPTC rates 30 days after application, bermudagrass was controlled 62% when incorporated with a rolling cultivator compared with 43% for the hipper/bedder. For johnsongrass and purple nutsedge, incorporation implements were equally effective and control with EPTC 30 days after application averaged 49 and 30%, respectively. Averaged across incorporation methods, control of all weeds 30 days after EPTC application was maximized at 3.9 kg/ha, but control was no greater than when applied at 2.0 kg/ha (45% bermudagrass, 57% johnsongrass, and 33% purple nutsedge control). EPTC treatments were followed by glyphosate at 2.24 kg ai/ha and weed control was compared with a glyphosate alone program consisting of two applications of glyphosate at 2.24 kg ai/ha. Where EPTC was applied 60 days earlier and followed by one application of glyphosate, weed control was no greater than when glyphosate was applied twice (bermudagrass ground cover no more than 5% and johnsongrass control at least 88%). In contrast, purple nutsedge was controlled 31 to 40% where EPTC was followed by one application of glyphosate compared with 63% for two applications of glyphosate. An economic analysis of EPTC and glyphosate programs was performed using herbicide costs and variable costs associated with operation of incorporation implements and herbicide application. Cost of EPTC at 2.0 kg/ha plus application and incorporation would be $38.36/ha with the rolling cultivator and$49.33/ha for the hipper/bedder. Where EPTC at 2.0 kg/ha is followed by glyphosate as Roundup Original Max®, total cost would be $18.66/ha more than where generic glyphosate is used. For EPTC at 2.0 kg/ha incorporated with a rolling cultivator and followed by generic glyphosate, total cost would be$15.31/ha more compared with generic glyphosate applied twice. In other research, EPTC applied at 2.9 to 6.8 kg/ha and incorporated at planting did not negatively affect sugarcane shoot population 35 and 186 days after planting compared with standard herbicide treatments. EPTC was ineffective on grass and broadleaf winter weeds

An economic analysis of the costs of alternative sugarcane fallow weed control programs

Economic research was conducted to present estimates of costs per acre associated with fallow sugarcane weed control programs for Louisiana in 2010. The 2010 projected costs are associated with the various phases of sugarcane fallow using different machinery, implements, and weed control practices followed by most growers in the main sugarcane production area of Louisiana. For bermudagrass and johnsongrass weed control treatments, the herbicides applied were Roundup Original Max at 46 oz/A, generic glyphosate at 64 oz/A, DuPont K4 60DG, Trifluralin 4EC at 4 qt/A, and EPTC at 3.5 pt/A. Purple nutsedge weed control treatments included Roundup Original Max at 46 oz/A, generic glyphosate at 64 oz/A, Permit 75DF at 1 oz/A, and Yukon 67.5WG at 6 oz/A. Roundup Original Max at 46 oz/A applied for perennial weed control was more expensive by $30.40 and$15.20 per acre compared with generic glyphosate treatments applied at 64 oz/A. Treatments applied with Roundup Original Max had a higher sugarcane fallow cost compared with treatments using generic glyphosate at current fuel, labor and herbicide input prices. A spreadsheet decision aid was developed which summarizes sugarcane fallow field operations and weed control costs, including equipment used, performance rates, and herbicides applied. These data can be entered by the user for specific farm situations, calculating total variable tillage and weed control costs per acre. Binary and non-binary linear programming were utilized to determine optimal sugarcane fallow weed control programs for bermudagrass, johnsongrass, and purple nutsedge control. The non-binary LP model selected treatments to achieve desired control of bermudagrass, johnsongrass and purple nutsedge and minimum cost program. In comparison, the binary LP model selected only one treatment that had minimum fallow field operation and weed control cost while satisfying minimum weed control levels. Generic glyphosate cost was found to be sensitive to price increases to $0.27 oz/A or above for bermudagrass control, and$0.33 oz/A for johnsongrass and purple nutsedge control. Fuel prices, directly impacting tillage costs, were found to not be sensitive in determining optimal weed control choices