Actividad lógica y relacional en educación infantil

El presente trabajo tiene como finalidad analizar la actividad lógica y relacional en Educación Infantil. Se presentan las producciones de niños de 4 y 5 años en actividades lógico-matemáticas de fichas de editoriales usuales y otras preparadas ad hoc. Los contenidos matemáticos involucrados son: seriación, tabla, adición y uso de códigos. Se siguió el método de doble ciego para evitar intervenciones condicionadas de las maestras. Los resultados obtenidos y su discusión sugieren recomendaciones para la enseñanza de los tópicos

An effort to make sense of antisense transcription in bacteria

Analysis of bacterial transcriptomes have shown the existence of a genome-wide process of overlapping transcription due to the presence of antisense RNAs, as well as mRNAs that overlapped in their entire length or in some portion of the 5′- and 3′-UTR regions. The biological advantages of such overlapping transcription are unclear but may play important regulatory roles at the level of transcription, RNA stability and translation. In a recent report, the human pathogen Staphylococcus aureus is observed to generate genome-wide overlapping transcription in the same bacterial cells leading to a collection of short RNA fragments generated by the endoribonuclease III, RNase III. This processing appears most prominently in Gram-positive bacteria. The implications of both the use of pervasive overlapping transcription and the processing of these double stranded templates into short RNAs are explored and the consequences discussed. © 2012 Landes Bioscience.This research was supported by grants ERA-NET Pathogenomics (PIM2010EPA-00606), BIO2008-05284-C02, BIO2011- 30503-C02 and BFU2011-23222 from Spanish Ministry of Economy and Competitiveness.A.T.-A. is recipient of “Ramon y Cajal” contracts from the Spanish Ministry of Science and Innovation. This research was supported by grants ERA-NET Pathogenomics (PIM2010EPA-00606), BIO2008-05284-C02, BIO2011-30503-C02 and BFU2011-23222 from Spanish Ministry of Economy and CompetitivenessPeer Reviewe

An effort to make sense of antisense transcription in bacteria

Analysis of bacterial transcriptomes have shown the existence of a genome-wide process of overlapping transcription due to the presence of antisense RNAs, as well as mRNAs that overlapped in their entire length or in some portion of the 5'- and 3'-UTR regions. The biological advantages of such overlapping transcription are unclear but may play important regulatory roles at the level of transcription, RNA stability and translation. In a recent report, the human pathogen Staphylococcus aureus is observed to generate genome-wide overlapping transcription in the same bacterial cells leading to a collection of short RNA fragments generated by the endoribonuclease III, RNase III. This processing appears most prominently in Gram-positive bacteria. The implications of both the use of pervasive overlapping transcription and the processing of these double stranded templates into short RNAs are explored and the consequences discussed

Significados conflictivos de ecuación y función en estudiantes de profesorado de secundaria

En el marco de una acción formativa sobre reconocimiento de las características del razonamiento algebraico elemental con estudiantes del máster de secundaria, especialidad matemáticas, se detecta que las nociones de función y ecuación interfieren la una en la otra. Así, en situaciones elementales en las que es preciso movilizar una función, identificando las variables independiente, dependiente y regla de correspondencia, los estudiantes interpretan la situación en términos de incógnitas y ecuaciones. Se describen algunas respuestas prototípicas de este fenómeno, el contexto y metodología de la investigación, así como algunas implicaciones para la formación de profesores

Construcción de la noción de número irracional en formación de profesores: conflictos semióticos y desafíos

La enseñanza y el aprendizaje formalizado de los números irracionales en la formación inicial de profesores de secundaria son problemáticos. Un análisis histórico y epistemológico de la noción de número irracional, sirve de base para enmarcar un estudio empírico, con estudiantes para profesor, que indaga el proceso de construcción de la noción de cardinalidad del conjunto de los números irracionales y la densidad de en R\Q en R. El estudio se realiza por medio de algunos elementos teóricos del enfoque ontosemiótico del conocimiento de y de la instrucción matemáticos. La identificación, por parte del estudiante, de la cardinalidad de conjuntos infinitos, hace posible la emergencia de fenómenos relativos a los cardinales transfinitos, determinándose diferentes tipos de errores y conflictos cognitivos

Uso de fichas en educación infantil: ilusión y utilidad

La utilización de fichas de trabajo en educación infantil es usual para la enseñanza de nociones lógicomatemáticas. Es preciso analizar la utilidad e interés en el uso de estas fichas y su impacto en el aprendizaje de los niños. Los contenidos matemáticos involucrados son: seriación, tabla, adición y uso de códigos. El análisis de las producciones de los niños permite denunciar el riesgo de un fenómeno de ilusión de la transparencia. Los resultados obtenidos y su discusión sugieren recomendaciones para la enseñanza de los tópicos

Radial Distribution of Particle Clusters in Down Flow Reactors

Particle clustering is of major importance in down flow reactors having a profound influence on some fundamental properties of the flowing suspension such as particle slip velocity. The goal of this study is to provide further evidence to support the formation of clusters using the novel CREC-GS-Optiprobes. This sensor is equipped with GRIN lenses and introduces minimum intrusion effects. Results reported include radial distributions of particle cluster size and velocity under various gas flow superficial velocities and suspension densities. Micro-scale and macro-scale flow structures are advanced on the basis of the reported data

First report of Lonchaeidae (Diptera) infesting fruits of Byrsonima crassifolia in Brazil.

Murici, Byrsonima crassifolia (L.) Kunth (Malpighiaceae), is native to the Amazon region and several other regions of tropical America. The fruits are small globose drupes with fleshy yellow mesocarp (pulp) and characteristic flavor and aroma. They are consumed fresh as juice, jam, liquor and sweets (León 1968; Donadio et al. 2002; Lorenzi et al. 2006). In addition, fruits of this species have been widely used in the traditional medicine by its antimicrobial and antidepressant properties (Martínez-Vázquez et al. 1999; Herrera-Ruiz et al. 2011). The only record of fruit flies (Diptera) associated to fruits of B. crassifolia in Brazil was published by Pereira et al. (2008) from material collected in the state of Amapá during 2005 and 2006. In their work, a total number of 7,915 fruits (16.02 kg) was collected in 24 sampling points distributed in the municipalities of Macapá, Mazagão and Porto Grande. Three samples were infested by fruit flies of the family Tephritidae (one in Macapá, 0.01 puparia/fruit; two in Mazagão, 0.10 and 0.15 puparia/fruit). Anastrepha striata Schiner, 1868 (10 specimens), A. obliqua (Macquart, 1835) (8 specimens) and A. fraterculus (Wiedemann, 1830) (3 specimens) were recovered in those collections. In other samples of B. crassifolia collected in the Brazilian Amazon (states of Amapá and Rondônia), no fruit flies specimens were obtained (Deus et al. 2009; Pereira et al. 2010; Silva et al. 2011a). In Mexico, the presence of A. serpentina (Wiedemann, 1830) in B. crassifolia was recorded in the state of Chiapas (Aluja et al. 1987). However, the presence of Lonchaeidae (Diptera) species in B. crassifolia was not recorded in either study

The evolution of Arbequina olive oil quality during ripening in a commercial super-high density orchard in north-east Spain

The objective of this work was to follow the maturity of the olives in a commercial Arbequina super-high density orchard and to study the evolution of the olive oil quality. For this objective, the physicochemical, nutritional and sensory parameters were studied. The free acidity was found to be similar during ripening whereas the peroxide index and K232, K270 decreased. The total phenol content and oxidative stability showed a similar trend. First, it increased and then decreased. alpha-tocopherol, saturated fatty acid and pungency decreased. The polyunsaturated content increased while the MUFAS/PUFAS ratio decreased. In 2010, the crop maturity was quicker, and the maturity indexes were higher than in the 2009 crop for the same picking date. Even in the same orchard, the maturity is changing in each crop season. For this reason, it is necessary to choose the optimal harvesting date