¿Qué nos dicen las investigaciones en didáctica de las matemáticas sobre la enseñanza de la derivada?

Como fragmento del trabajo de grado de la Maestría en Docencia de la Matemática en la Universidad Pedagógica Nacional, se presenta una descripción y clasificación de investigaciones sobre la enseñanza de la derivada realizadas en los campos de la Educación Matemática y de la Educación del Profesor de Matemáticas , para lo cual se emplean en los enfoques descritos por Font (2002) y por Guacaneme & Mora (2013), respectivamente, con el propósito de determinar qué enfoques están siendo usados en las investigaciones realizadas en los campos. A través de esta clasificación se evidenció una tendencia por los enfoques sistémico y semiótico y escasos trabajos en enfoques socioculturales

Asedios de la prensa de barricada y la prensa satírica en el Chile del siglo XIX

This article explores the transgressor dimension of the barrice press and the satirical press in the 19th century in Chile in the context of formation of Republics.The analysis pretends to establish that both types of newspapers were a fundamental weapon in the transformation and intervention in nineteenth-century society. This is reflected in the journals of authors as Santiago Arcos, Eusebio Lillo, Francisco Bilbao y Juan Rafael Allende. The study of these types of press serves as an approach to a foundational period, in which the political, social and economic features of the American countries were configured.El presente artículo tiene como propósito explorar la dimensión transgresora de la prensa de barricada y la prensa satírica del siglo XIX en Chile, en el contexto de formación de repúblicas. A través de la revisión de los periódicos de autores como Santiago Arcos, Eusebio Lillo, Francisco Bilbao y Juan Rafael Allende, el análisis propuesto busca postular ambos tipos de prensa como un arma fundamental de transformación e intervención en la sociedad decimonónica. El estudio de estos tipos de prensa sirve como acercamiento a un periodo fundacional, en el que se configuraron los rasgos políticos, sociales y económicos de los países americanos

Oral diseases : a 14-year experience of a Chilean institution with a systematic review from eight countries

Retrospective studies to assess the distribution of oral diseases (ODs) are helpful in estimating the prevalence of oral diagnoses in the population, and thus help in preventive and curative services. Prevalence and frequency data for ODs are available from many countries, but information from Chile is scarce. This study investigated the frequency of ODs in a Chilean population. For this, we included all patients treated at the University of Talca (UTALCA, Chile) between 2001 and 2014. Patient characteristics were retrieved from medical files. To contextualize our results, we conducted a systematic review (SystRev) using Publish or Perish software (PoP), Google Scholar and MEDLINE/PubMed. One hundred sixty-six ODs were diagnosed, and the most prevalent groups were soft tissue tumours, epithelial pathology and salivary gland pathology. Individually, irritation fibroma, oral lichen planus (OLP) and mucocele were the most common diagnoses. ODs frequently affected unspecified parts of the mouth (including cheek, vestibule and retromolar area), gum, lips, tongue and palate. In the SystRev, the more studied diagnoses were leukoplakia, OLP and recurrent aphthous stomatitis; prevalent lesions included Fordyce?s spots, recurrent aphthous stomatitis and fissured tongue. Chilean patients and SistRev shared almost all ODs. The results reflect ODs diagnosed in a specialized service of oral pathology and medicine in Chile and will allow the establishment of preventive/curative policies, adequate health services and dentistry curriculum

Abundance analysis of planet-hosting and debris-disk stars

Abstract: We present an analysis of element abundances in planet-hosting and debrisdisk stars based on high-resolution spectra obtained with the FEROS echelle spectrograph and the 2.2-m ESO telescope at La Silla. Atmospheric parameters and abundance patterns for the stars are determined. A comparison of the abundances is made between planethosting stars, debris-disk stars, and field starshttp://astars2013.inasan.ru/proceedings/publishedVersionFil: Carolina Andrea Chavero. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

Abundance Pattern Analysis of Planet-hosting and Debris-disk Stars

Abstract: About 16 % of the main-sequence solar-like stars are surrounded by dusty debris disks (DD). These disks are the detritus of small bodies collisions and their presence is a very strong signpost of planet formation. One of the most interesting characteristics of stars hosting a giant planet is a direct relationship between metallicity and probability of planet formation, which was found to increase with stellar metallicity Gonzalez (1997). Instead, the small planets would form around host stars (HS) with a wide range of metallicities (Buchhave et al. 2012). On the other hand the presence of debris disks is uncorrelated with metallicity (Chavero et al. 2006, Greaves et al. 2006, Maldonado et al. 2012).http://www.aspbooks.org/a/volumes/article_details/?paper_id=36464Fil: Chavero, Carolina Andrea. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Chavero, Carolina Andrea. Conicet. Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

Control de tráfico adaptativo para una intersección de dos accesos

En Colombia, los semáforos normales se programan con tiempos estáticos e intervalos constantes en sus ciclos. Cuando un evento extraordinario ocurre (como colisiones o pinchadas) el tráfico se vuelve anormal en una de los accesos pretenecientes a la intersección, resultando restrasos y haciendo que la programación del semáforo sea inadecuada para manejar la situación. En este artículo se presenta un modelo de comportamiento adaptativo para estudiar la optimización de las demoras de tiempo en una intersección de dos accesos controlada por semaforos usando Algoritmos Genéricos (AG)

Turbulencia empresarial en Colombia : sector de seguros

En el año 2010, la Facultad de Administración de la Universidad del Rosario puso en marcha un proyecto de investigación donde se exploraba el fenómeno de la turbulencia empresarial. En este momento han sido publicados más de 15 documentos donde se realiza la descripción de lo ocurrido en igual número de sectores. En este número se realiza un análisis del sector asegurador, actividad empresarial que contribuye de manera significativa a la economía del país. El trabajo ha sido realizado de manera conjunta por los profesores Natalia Malaver y Hugo Rivera de la asignatura Estrategia de empresa I, con estudiantes del pregrado de la Facultad, quienes se motivaron por encontrar respuestas a la forma como algunas empresas del sector enfrentan la turbulencia sectorial. La estructura del documento incluye una breve descripción del sector; luego un análisis de la turbulencia, y un estudio sectorial realizado aplicando la metodología del Análisis Estructural de Sectores Estratégicos (AESE) desarrollada por el grupo de investigación en perdurabilidad empresarial de la Facultad de Aministración de la Universidad del Rosario

The autoimmune ecology

Autoimmune diseases (ADs) represent a heterogeneous group of disorders that affect specific target organs or multiple organ systems. These conditions share common immunopathogenic mechanisms (i.e., the autoimmune tautology), which explain the clinical similarities they have among them as well as their familial clustering (i.e., coaggregation). As part of the autoimmune tautology, the influence of environmental exposure on the risk of developing ADs is paramount (i.e., the autoimmune ecology). In fact, environment, more than genetics, shapes immune system. Autoimmune ecology is akin to exposome, that is all the exposures - internal and external - across the lifespan, interacting with hereditary factors (both genetics and epigenetics) to favor or protect against autoimmunity and its outcomes. Herein, we provide an overview of the autoimmune ecology, focusing on the immune response to environmental agents in general, and microbiota, cigarette smoking, alcohol and coffee consumption, socioeconomic status (SES), gender and sex hormones, vitamin D, organic solvents, and vaccines in particular. Inclusion of the autoimmune ecology in disease etiology and health will improve the way personalized medicine is currently conceived and applied. © 2016 Anaya, Ramirez-Santana, Alzate, Molano-Gonzalez and Rojas-Villarraga

Fungal colonization with Pneumocystis correlates to increasing chloride channel accessory 1 (hCLCA1) suggesting a pathway for up-regulation of airway mucus responses, in infant lungs

AbstractFungal colonization with Pneumocystis is associated with increased airway mucus in infants during their primary Pneumocystis infection, and to severity of COPD in adults. The pathogenic mechanisms are under investigation. Interestingly, increased levels of hCLCA1 – a member of the calcium-sensitive chloride conductance family of proteins that drives mucus hypersecretion – have been associated with increased mucus production in patients diagnosed with COPD and in immunocompetent rodents with Pneumocystis infection. Pneumocystis is highly prevalent in infants; therefore, the contribution of Pneumocystis to hCLCA1 expression was examined in autopsied infant lungs. Respiratory viruses that may potentially increase mucus, were also examined. hCLCA1 expression was measured using actin-normalized Western-blot, and the burden of Pneumocystis organisms was quantified by qPCR in 55 autopsied lungs from apparently healthy infants who died in the community. Respiratory viruses were diagnosed using RT-PCR for RSV, metapneumovirus, influenza, and parainfluenza viruses; and by PCR for adenovirus. hCLCA1 levels in virus positive samples were comparable to those in virus-negative samples. An association between Pneumocystis and increased hCLCA1 expression was documented (P=0.028). Additionally, increasing Pneumocystis burden correlated with increasing hCLCA1 protein expression levels (P=0.017). Results strengthen the evidence of Pneumocystis-associated up-regulation of mucus-related airway responses in infant lungs. Further characterization of this immunocompetent host-Pneumocystis-interaction, including assessment of potential clinical significance, is warranted

Organic solvents as risk factor for autoimmune diseases: a systematic review and meta-analysis

Background: Genetic and epigenetic factors interacting with the environment over time are the main causes of complex diseases such as autoimmune diseases (ADs). Among the environmental factors are organic solvents (OSs), which are chemical compounds used routinely in commercial industries. Since controversy exists over whether ADs are caused by OSs, a systematic review and meta-analysis were performed to assess the association between OSs and ADs. Methods and Findings: The systematic search was done in the PubMed, SCOPUS, SciELO and LILACS databases up to February 2012. Any type of study that used accepted classification criteria for ADs and had information about exposure to OSs was selected. Out of a total of 103 articles retrieved, 33 were finally included in the meta-analysis. The final odds ratios (ORs) and 95% confidence intervals (CIs) were obtained by the random effect model. A sensitivity analysis confirmed results were not sensitive to restrictions on the data included. Publication bias was trivial. Exposure to OSs was associated to systemic sclerosis, primary systemic vasculitis and multiple sclerosis individually and also to all the ADs evaluated and taken together as a single trait (OR: 1.54; 95% CI: 1.25-1.92; p-value, 0.001). Conclusion: Exposure to OSs is a risk factor for developing ADs. As a corollary, individuals with non-modifiable risk factors (i.e., familial autoimmunity or carrying genetic factors) should avoid any exposure to OSs in order to avoid increasing their risk of ADs