Second graders articulating ideas about linear functional relationships

In this paper, we explore the ideas that second grade students articulate about functional relationships. We adopt a function-based approach to introduce elementary school children to algebraic content. We present results from a design-based research study carried out with 21 second-grade students (approximately 7 years of age). We focus on a lesson from our classroom teaching experiment in which the students were working on a problem that involved a linear functional relationship (y=2x). From the analysis of students’ written work and classroom video, we illustrate two different approaches that students adopt to express the relationship between two quantities. Students show fluency recontextualizing the problem posed, moving between extra-mathematical and intra-mathematical contexts

The development of algebraic thinking in children of primary school

Este artículo presenta los resultados de investigaciones focalizadas en el desarrollo del pensamiento algebraico en niños de escolaridad primaria. Se centra, específicamente, en el desarrollo del pensamiento funcional y en la práctica representacional, atendiendo a la apropiación de las tablas y las letras para representar cantidades indeterminadas por parte de niños de primer grado. Estos estudios muestran los recursos que manifiestan los niños para desarrollar su pensamiento funcional y para usar tablas y letras en contextos algebraicos. Estos resultados se oponen a los de estudios clásicos que habían enfatizado las grandes dificultades de estudiantes adolescentes a la hora de aprender álgebra. El artículo finaliza con reflexiones a nivel metodológico y teórico en cuanto a estos estudios de investigación.This article presents an overview of the results of studies that have focused on the development of algebraic thinking among young elementary school children. Specifically, it centers on the development of functional thinking and the algebraic practice of representation, with a focus on the appropriation of tables and notation for variables among first grade children. These studies show the resources that children have to develop functional thinking and to use tables and notation for variables in algebraic contexts. These results are contrasted with earlier studies that had emphasized the great difficulties that adolescent students have in learning algebra. In closing, the article provides methodological and theoretical reflections related to these research studies.Facultad de Psicologí

The development of algebraic thinking in children of primary school

Este artículo presenta los resultados de investigaciones focalizadas en el desarrollo del pensamiento algebraico en niños de escolaridad primaria. Se centra, específicamente, en el desarrollo del pensamiento funcional y en la práctica representacional, atendiendo a la apropiación de las tablas y las letras para representar cantidades indeterminadas por parte de niños de primer grado. Estos estudios muestran los recursos que manifiestan los niños para desarrollar su pensamiento funcional y para usar tablas y letras en contextos algebraicos. Estos resultados se oponen a los de estudios clásicos que habían enfatizado las grandes dificultades de estudiantes adolescentes a la hora de aprender álgebra. El artículo finaliza con reflexiones a nivel metodológico y teórico en cuanto a estos estudios de investigación.This article presents an overview of the results of studies that have focused on the development of algebraic thinking among young elementary school children. Specifically, it centers on the development of functional thinking and the algebraic practice of representation, with a focus on the appropriation of tables and notation for variables among first grade children. These studies show the resources that children have to develop functional thinking and to use tables and notation for variables in algebraic contexts. These results are contrasted with earlier studies that had emphasized the great difficulties that adolescent students have in learning algebra. In closing, the article provides methodological and theoretical reflections related to these research studies.Facultad de Psicologí

The development of algebraic thinking in children of primary school

Este artículo presenta los resultados de investigaciones focalizadas en el desarrollo del pensamiento algebraico en niños de escolaridad primaria. Se centra, específicamente, en el desarrollo del pensamiento funcional y en la práctica representacional, atendiendo a la apropiación de las tablas y las letras para representar cantidades indeterminadas por parte de niños de primer grado. Estos estudios muestran los recursos que manifiestan los niños para desarrollar su pensamiento funcional y para usar tablas y letras en contextos algebraicos. Estos resultados se oponen a los de estudios clásicos que habían enfatizado las grandes dificultades de estudiantes adolescentes a la hora de aprender álgebra. El artículo finaliza con reflexiones a nivel metodológico y teórico en cuanto a estos estudios de investigación.This article presents an overview of the results of studies that have focused on the development of algebraic thinking among young elementary school children. Specifically, it centers on the development of functional thinking and the algebraic practice of representation, with a focus on the appropriation of tables and notation for variables among first grade children. These studies show the resources that children have to develop functional thinking and to use tables and notation for variables in algebraic contexts. These results are contrasted with earlier studies that had emphasized the great difficulties that adolescent students have in learning algebra. In closing, the article provides methodological and theoretical reflections related to these research studies.Facultad de Psicologí

Three novel and the common Arg677Ter RP1 protein truncating mutations causing autosomal dominant retinitis pigmentosa in a Spanish population

BACKGROUND: Retinitis pigmentosa (RP), a clinically and genetically heterogeneous group of retinal degeneration disorders affecting the photoreceptor cells, is one of the leading causes of genetic blindness. Mutations in the photoreceptor-specific gene RP1 account for 3–10% of cases of autosomal dominant RP (adRP). Most of these mutations are clustered in a 500 bp region of exon 4 of RP1. METHODS: Denaturing gradient gel electrophoresis (DGGE) analysis and direct genomic sequencing were used to evaluate the 5' coding region of exon 4 of the RP1 gene for mutations in 150 unrelated index adRP patients. Ophthalmic and electrophysiological examination of RP patients and relatives according to pre-existing protocols were carried out. RESULTS: Three novel disease-causing mutations in RP1 were detected: Q686X, K705fsX712 and K722fsX737, predicting truncated proteins. One novel missense mutation, Thr752Met, was detected in one family but the mutation does not co-segregate in the family, thereby excluding this amino acid variation in the protein as a cause of the disease. We found the Arg677Ter mutation, previously reported in other populations, in two independent families, confirming that this mutation is also present in a Spanish population. CONCLUSION: Most of the mutations reported in the RP1 gene associated with adRP are expected to encode mutant truncated proteins that are approximately one third or half of the size of wild type protein. Patients with mutations in RP1 showed mild RP with variability in phenotype severity. We also observed several cases of non-penetrant mutations

Marvin : a tool kit for streamlined access and visualization of the SDSS-IV MaNGA data set

The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, one of three core programs of the fourth-generation Sloan Digital Sky Survey (SDSS-IV), is producing a massive, high-dimensional integral field spectroscopic data set. However, leveraging the MaNGA data set to address key questions about galaxy formation presents serious data-related challenges due to the combination of its spatially interconnected measurements and sheer volume. For each galaxy, the MaNGA pipelines produce relatively large data files to preserve the spatial correlations of the spectra and measurements, but this comes at the expense of storing the data set in coarse units or "chunks." This coarse chunking and the total volume of the data make it time-consuming to download and curate locally stored data. Thus, accessing, querying, visually exploring, and performing statistical analyses across the whole data set at a fine-grained scale is extremely challenging using just FITS files. To overcome these challenges, we have developed Marvin, a toolkit consisting of a Python package, Application Programming Interface, and web application utilizing a remote database. Marvin allows users to seamlessly work with MaNGA data by abstracting both remote and local (on-disk) interactions to behind-the-scenes data-handling functions. Combining this capability with additional processing and querying tools, users can create powerful Python workflows that are easy to import and share. Marvin's web application uses these tools to enable "point-and-click" examination of data cubes and derived maps, as well as search queries for all publicly released MaNGA galaxies. Marvin's robust and sustainable design minimizes maintenance, while facilitating user-contributed extensions such as high-level analysis code.Publisher PDFPeer reviewe

A Research Agenda for Helminth Diseases of Humans: Intervention for Control and Elimination

Recognising the burden helminth infections impose on human populations, and particularly the poor, major intervention programmes have been launched to control onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, and cysticercosis. The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. A summary of current helminth control initiatives is presented and available tools are described. Most of these programmes are highly dependent on mass drug administration (MDA) of anthelmintic drugs (donated or available at low cost) and require annual or biannual treatment of large numbers of at-risk populations, over prolonged periods of time. The continuation of prolonged MDA with a limited number of anthelmintics greatly increases the probability that drug resistance will develop, which would raise serious problems for continuation of control and the achievement of elimination. Most initiatives have focussed on a single type of helminth infection, but recognition of co-endemicity and polyparasitism is leading to more integration of control. An understanding of the implications of control integration for implementation, treatment coverage, combination of pharmaceuticals, and monitoring is needed. To achieve the goals of morbidity reduction or elimination of infection, novel tools need to be developed, including more efficacious drugs, vaccines, and/or antivectorial agents, new diagnostics for infection and assessment of drug efficacy, and markers for possible anthelmintic resistance. In addition, there is a need for the development of new formulations of some existing anthelmintics (e.g., paediatric formulations). To achieve ultimate elimination of helminth parasites, treatments for the above mentioned helminthiases, and for taeniasis and food-borne trematodiases, will need to be integrated with monitoring, education, sanitation, access to health services, and where appropriate, vector control or reduction of the parasite reservoir in alternative hosts. Based on an analysis of current knowledge gaps and identification of priorities, a research and development agenda for intervention tools considered necessary for control and elimination of human helminthiases is presented, and the challenges to be confronted are discussed

A Research Agenda for Helminth Diseases of Humans: Basic Research and Enabling Technologies to Support Control and Elimination of Helminthiases

Successful and sustainable intervention against human helminthiases depends on optimal utilisation of available control measures and development of new tools and strategies, as well as an understanding of the evolutionary implications of prolonged intervention on parasite populations and those of their hosts and vectors. This will depend largely on updated knowledge of relevant and fundamental parasite biology. There is a need, therefore, to exploit and apply new knowledge and techniques in order to make significant and novel gains in combating helminthiases and supporting the sustainability of current and successful mass drug administration (MDA) programmes. Among the fields of basic research that are likely to yield improved control tools, the Disease Reference Group on Helminth Infections (DRG4) has identified four broad areas that stand out as central to the development of the next generation of helminth control measures: 1) parasite genetics, genomics, and functional genomics; 2) parasite immunology; 3) (vertebrate) host–parasite interactions and immunopathology; and 4) (invertebrate) host–parasite interactions and transmission biology. The DRG4 was established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR). The Group was given the mandate to undertake a comprehensive review of recent advances in helminthiases research in order to identify notable gaps and highlight priority areas. This paper summarises recent advances and discusses challenges in the investigation of the fundamental biology of those helminth parasites under the DRG4 Group's remit according to the identified priorities, and presents a research and development agenda for basic parasite research and enabling technologies that will help support control and elimination efforts against human helminthiases

Marvin:a tool kit for streamlined access and visualization of the SDSS-IV MaNGA data set

The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, one of three core programs of the fourth-generation Sloan Digital Sky Survey (SDSS-IV), is producing a massive, high-dimensional integral field spectroscopic data set. However, leveraging the MaNGA data set to address key questions about galaxy formation presents serious data-related challenges due to the combination of its spatially interconnected measurements and sheer volume. For each galaxy, the MaNGA pipelines produce relatively large data files to preserve the spatial correlations of the spectra and measurements, but this comes at the expense of storing the data set in coarse units or "chunks." This coarse chunking and the total volume of the data make it time-consuming to download and curate locally stored data. Thus, accessing, querying, visually exploring, and performing statistical analyses across the whole data set at a fine-grained scale is extremely challenging using just FITS files. To overcome these challenges, we have developed Marvin, a toolkit consisting of a Python package, Application Programming Interface, and web application utilizing a remote database. Marvin allows users to seamlessly work with MaNGA data by abstracting both remote and local (on-disk) interactions to behind-the-scenes data-handling functions. Combining this capability with additional processing and querying tools, users can create powerful Python workflows that are easy to import and share. Marvin's web application uses these tools to enable "point-and-click" examination of data cubes and derived maps, as well as search queries for all publicly released MaNGA galaxies. Marvin's robust and sustainable design minimizes maintenance, while facilitating user-contributed extensions such as high-level analysis code