El analisis didáctico como una herramienta para identificar los dominios de conocimiento matemático para la enseñanza de las fracciones

Caracterizar los componentes del conocimiento matemático para la enseñanza (MKT)es un tema ampliamente abordado en las investigaciones en educación matemática. Sin embargo, identificar en la práctica los distintos tipos de conocimientos necesarios para enseñar es una cuestión aún carente en los estudios. Presentamos un ejemplo, de cómo parte del análisis didáctico del contenido matemático escolar de las fracciones, puede emplearse para identificar distintos tipos de conocimientos declarados en un proceso de enseñanza-aprendizaje

Características para identificar a profesores de matemáticas expertos

Presentamos características que distinguen a los profesores de matemáticas expertos. Las particularidades surgen de la revisión de investigaciones relacionadas con la naturaleza de la experiencia pedagógica, que permiten extraer características primarias y secundarias que distinguen a estos docentes. Las primarias aluden a cuestiones específicas del conocimiento y aspectos de su enseñanza, mientras que las secundarias se refieren a los años de experiencia docente, reconocimiento por parte de su entorno educativo y participación en procesos de actualización constante en su disciplina, entre otros. Finalmente, exponemos el caso de un profesor seleccionado según las características secundarias descritas, revelándose la necesidad de considerar las características primarias si pretendemos profundizar en la comprensión de la naturaleza del conocimiento matemático para la enseñanza

Caracterización del conocimiento matemático para la enseñanza de los números racionales

Este artículo forma parte de una investigación más amplia que pretende analizar el conocimiento matemático para la enseñanza que pone en juego el profesor al enseñar los números racionales. Presentamos la relación teórica que se está utilizando para identificar componentes de conocimiento matemático que el profesor manifiesta en su acción docente, correspondencia que se fundamenta en el modelo de conocimiento matemático para la enseñanza y en el análisis didáctico. Concluimos, ejemplificando con el análisis de episodios de clase

Letter from Janet E. Davison, Wellesley, Massachusetts, to Mrs. R. J. Davison, Bath, New York, 1915 May 16

https://repository.wellesley.edu/studentcordavison/1275/thumbnail.jp

Diffusion of obscene content within Protection Child’s Schedule in Peru: Analysis of reality show Esto es Guerra

En el presente artículo se analiza el contenido que difunde Esto es Guerra, el reality show peruano con alto índice de preferencia en la audiencia infantil durante el 2014, acusado de transmitir escenas con contenido sexual. El objetivo de esta investigación es determinar si existen rastros de material obsceno en este bloque televisivo y si este transgrede el Horario de Protección al Menor, reconocido en el marco legal peruano. Su justificación se enmarca en la escasez de estudios que se han realizado sobre realities en el Perú, los constantes pedidos de la sociedad para que este programa deje de transmitirse y las sanciones que ha recibido de parte de organismos estatales. La metodología empleada se basa en un análisis de contenido de la séptima temporada de Esto es Guerra, en el que se tendrán en cuenta los mensajes que transmiten los conductores y participantes a través de su comportamiento. La investigación determinó que el reality show de competencia presenta segmentos que podrían ser considerados como obscenos, aunque su duración es muy limitada y no representativa en relación a todo el programa.In the present article, there is analyzed the content that spreads Esto es Guerra, Peruvian reality show which had a higher preference index in the child audience during 2014, accused of transmitting scenes with sexual content. The objective of this investigation is to determine if in there exist traces of obscene material and if this violate the Protection Child’s Schedule, recognized in the legal Peruvian frame. His justification is put in the shortage of studies that have been realized on reality shows in Peru, the constant society’s requests in order that this programs stops to transmit at television and the sanctions that it has received on behalf of state organisms. The methodology is based on an analysis of content of seventh season of Esto es Guerra, in that will be considering the messages that the presenters and participants transmit across their behavior. The investigation determined that the reality show of competition presents segments that might be considered obscene, but its duration is very limited and not representative in relation to the entire program

Uptake and Effects of Cylindrospermopsin: Biochemical, Physiological and Biometric Responses in The Submerged Macrophyte Egeria densa Planch

Cylindrospermopsin (CYN) is being detected in surface waters more commonly and frequently worldwide. This stable, extracellular cyanotoxin causes protein synthesis inhibition, thus posing a risk to aquatic biota, including macrophytes, which serve as primary producers. Nevertheless, data regarding the effects caused by environmental concentrations of CYN is still limited. In the presented study, the uptake of CYN at environmental concentrations by the submerged macrophyte Egeria densa was investigated. Bioaccumulation, changes in the plant biomass, as well as shoot-length were assessed as responses. Variations in the cellular H2O2 levels, antioxidative enzyme activities, as well as concentrations and ratios of the photosynthetic pigments were also measured. E. densa removed 54% of CYN within 24 h and up to 68% after 336 h; however, CYN was not bioaccumulated. The antioxidative enzyme system was activated by CYN exposure. Pigment concentrations decreased with exposure but normalized after 168 h. The chlorophyll a to b ratio increased but normalized quickly thereafter. Carotenoids and the ratio of carotenoids to total chlorophylls increased after 96 h suggesting participation in the antioxidative system. Growth stimulation was observed. The ability to remove CYN and resistance to CYN toxicity within 14 days proved E. densa as suitable for phytoremediation; nonetheless, prolonged exposure (32 days) resulted in adverse effects related to CYN uptake, which needs to be studied further

Kinematic study of planetary nebulae in NGC 6822

By measuring precise radial velocities of planetary nebulae (which belong to the intermediate age population), H II regions, and A-type supergiant stars (which are members of the young population) in NGC 6822, we aim to determine if both types of population share the kinematics of the disk of H I found in this galaxy. Spectroscopic data for four planetary nebulae were obtained with the high spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the Magellan telescope at Las Campanas Observatory. Data for other three PNe and one H II region were obtained from the SPM Catalog of Extragalactic Planetary Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m telescope at the Observatorio Astron\'omico Nacional, M\'exico. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 5-6 km s$^{-1}$. Data for three additional H II regions and a couple of A-type supergiant stars were collected from the literature. The heliocentric radial velocities of the different objects were compared to the velocities of the H i disk at the same position. From the analysis of radial velocities it is found that H II regions and A-type supergiants do share the kinematics of the H I disk at the same position, as expected for these young objects. On the contrary, planetary nebula velocities differ significantly from that of the H I at the same position. The kinematics of planetary nebulae is independent from the young population kinematics and it is closer to the behavior shown by carbon stars, which are intermediate-age members of the stellar spheroid existing in this galaxy. Our results are confirming that there are at least two very different kinematical systems in NGC 6822