An Exploratory Study of Attributes, Affordances, Abilities, and Distance in Children\u27s Use of Mathematics Virtual Manipulative iPad Apps

This exploratory qualitative study investigated the presence of and relationships among constructs that contribute to children\u27s interactions with educational technology, leading to the development of the modification of attributes, affordances, abilities, and distance (MAAAD) for Learning framework. For this study, each of 10 fifth-grade children participated in one individual video-recorded semistructured interview session, during which they interacted with two mathematics virtual manipulative iPad apps and responded to follow-up questions. Video recordings and observation field notes were analyzed for evidence of attributes, affordance-ability relationships, distance, and relationships among these constructs. Constant comparative data analysis using memoing and eclectic coding provided evidence of the presence of each focus construct. Further analysis and interpretation, including quantization of qualitative data for visualization using novel rhombus plots, also led to the identification of emergent themes related to each construct and revealed relationships among the constructs. Emergent themes included categorization, alignment, and modification of attributes, variations and interrelationships among affordance-ability relationships, and the identification of and interactions among mathematical and technological distance. Furthermore, each construct related to each other construct. The evidence and interpretations led to the development of the MAAAD for Learning framework. The results of the study suggest that the MAAAD for Learning framework models relationships among attributes, affordance-ability relationships, and distance in the context of user-app interactions. the framework could serve as a tool for app developers designing apps, educators using apps to support children\u27s learning, and researchers characterizing user-app interactions and the outcomes of those interactions. The constructs, relationships, and framework identified in this study advance the literature on children\u27s interactions with educational technology tools, in particular literature concerning children\u27s interactions with mathematics virtual manipulative iPad apps

Living and Teaching in Two Worlds: Professional Identity Development in Transnational Dual Language Immersion Teachers

This study explores how transnational teachers working in dual language immersion schools in the United States negotiate their professional identity to pursue a career in teaching. Researchers pay attention to tensions between transnational teachers’ individual agency and the sociocultural influence of the workplace. An important issue is how chainging teacher’s professional identity impacts the ways in which they implement curriulum, particularly related to accountability. Framed by third space theory, we explore their heterogeneous stories and socio-culturally contextualized teaching experiences via a qualitative multiple case study. The three teachers wer all teaching Spanish or Chinese in urban public elementary schools in the Intermountain West region of the United States. Data sources include a semester long classroom observation, semi-structured teacher interviews, informal conversations with the teachers, teacher journal entries, and artifacts. Our results indicate that these teachers’ professional identity development processes were diverse, complex, and ongoing. All three displayed multicultural awareness regarding the codes of their new educational and cultural settings and exercised their agency through strong self-concept and frequent reflection within their situated contexts. Their prior cross-cultural teaching and schooling experiences served as a springboard that enabled them to gain a better understanding of their culturally and linguistically diverse students and to teach their target languages by incorporating elements of their students’ sociocultural backgrounds. This study supports a rich sociocultural appreciation of the processes and contexts of transnational teachers’ professional identity development. Keywords: Professional identity development, teacher identity, transnational teacher, third space theory, dual language immersio

Developing number sense with Fingu: a preschooler’s embodied mathematics during interactions with a multi-touch digital game

Early number sense, including subitizing and composition, is a foundation for mathematics, and bodies, especially fingers, are integral to number sense. Multi-touch technology offers innovative opportunities for developing and studying number sense, especially using conceptually congruent gestures that match the mathematics. However, there have been few investigations of the development of early number sense, particularly in embodied forms. Therefore, this mixed-methods study explores a preschooler’s development of early number sense during a month of interactions with the multi-touch digital mathematics game Fingu. Key findings related to the development of early number sense include relevance of configuration and quantity, relationships among gestures and quantities, and development of estimation and precision. This research adds new perspectives to our understandings of early number sense research and practice, calling for consideration of embodiment and conceptually congruent gestures

Exploring the Phenomenon of Distance in Children\u27s Interactions with Touchscreen Digital Mathematics Games

This study examines the construct of distance – the degree of difficulty of interacting with something – as part of activity involving children using touchscreen digital games to learn mathematics. Ten fifth-grade children engaged in video-recorded semi-structured task-based interviews in which they used two touchscreen digital mathematics games on a touchscreen tablet and responded to semi-structured follow-up questions. Qualitative data analysis was iterative, featuring analytic memoing and eclectic coding techniques to identify themes related to distance. In advanced coding stages, magnitude coding was used to characterize the degree of distance present. Findings provide evidence of the presence of distance, changes in distance, and interactions between distance types throughout the activity. In particular, both mathematical distance and technological distance were present, changed in various ways, and often influenced each other. Implications include the relevance of distance for designing, implementing, and researching educational technology

Magellan/M2FS Spectroscopy of Galaxy Clusters: Stellar Population Model and Application to Abell 267

We report the results of a pilot program to use the Magellan/M2FS spectrograph to survey the galactic populations and internal kinematics of galaxy clusters. For this initial study, we present spectroscopic measurements for $223$ quiescent galaxies observed along the line of sight to the galaxy cluster Abell 267 ($z\sim0.23$). We develop a Bayesian method for modeling the integrated light from each galaxy as a simple stellar population, with free parameters that specify redshift ($v_\mathrm{los}/c$) and characteristic age, metallicity ($\mathrm{[Fe/H]}$), alpha-abundance ($[\alpha/\mathrm{Fe}]$), and internal velocity dispersion ($\sigma_\mathrm{int}$) for individual galaxies. Parameter estimates derived from our 1.5-hour observation of A267 have median random errors of $\sigma_{v_\mathrm{los}}=20\ \mathrm{km\ s^{-1}}$, $\sigma_{\mathrm{Age}}=1.2\ \mathrm{Gyr}$, $\sigma_{\mathrm{[Fe/H]}}=0.11\ \mathrm{dex}$,$\sigma_{[\alpha/\mathrm{Fe}]}=0.07\ \mathrm{dex}$, and$\sigma_{\sigma_\mathrm{int}}=20\ \mathrm{km\ s^{-1}}$. In a companion paper, we use these results to model the structure and internal kinematics of A267.Comment: 16 pages, 11 figures, accepted for publication in The Astronomical Journa

Improved Imputation of Common and Uncommon Single Nucleotide Polymorphisms (SNPs) with a New Reference Set

Statistical imputation of genotype data is an important technique for analysis of genome-wide association studies (GWAS). We have built a reference dataset to improve imputation accuracy for studies of individuals of primarily European descent using genotype data from the Hap1, Omni1, and Omni2.5 human SNP arrays (Illumina). Our dataset contains 2.5-3.1 million variants for 930 European, 157 Asian, and 162 African/African-American individuals. Imputation accuracy of European data from Hap660 or OmniExpress array content, measured by the proportion of variants imputed with R^2^>0.8, improved by 34%, 23% and 12% for variants with MAF of 3%, 5% and 10%, respectively, compared to imputation using publicly available data from 1,000 Genomes and International HapMap projects. The improved accuracy with the use of the new dataset could increase the power for GWAS by as much as 8% relative to genotyping all variants. This reference dataset is available to the scientific community through the NCBI dbGaP portal. Future versions will include additional genotype data as well as non-European populations

Galaxy Clustering in Early SDSS Redshift Data

We present the first measurements of clustering in the Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists of 29,300 galaxies with redshifts 5,700 km/s < cz < 39,000 km/s, distributed in several long but narrow (2.5-5 degree) segments, covering 690 square degrees. For the full, flux-limited sample, the redshift-space correlation length is approximately 8 Mpc/h. The two-dimensional correlation function \xi(r_p,\pi) shows clear signatures of both the small-scale, ``fingers-of-God'' distortion caused by velocity dispersions in collapsed objects and the large-scale compression caused by coherent flows, though the latter cannot be measured with high precision in the present sample. The inferred real-space correlation function is well described by a power law, \xi(r)=(r/6.1+/-0.2 Mpc/h)^{-1.75+/-0.03}, for 0.1 Mpc/h < r < 16 Mpc/h. The galaxy pairwise velocity dispersion is \sigma_{12} ~ 600+/-100 km/s for projected separations 0.15 Mpc/h < r_p < 5 Mpc/h. When we divide the sample by color, the red galaxies exhibit a stronger and steeper real-space correlation function and a higher pairwise velocity dispersion than do the blue galaxies. The relative behavior of subsamples defined by high/low profile concentration or high/low surface brightness is qualitatively similar to that of the red/blue subsamples. Our most striking result is a clear measurement of scale-independent luminosity bias at r < 10 Mpc/h: subsamples with absolute magnitude ranges centered on M_*-1.5, M_*, and M_*+1.5 have real-space correlation functions that are parallel power laws of slope ~ -1.8 with correlation lengths of approximately 7.4 Mpc/h, 6.3 Mpc/h, and 4.7 Mpc/h, respectively.Comment: 51 pages, 18 figures. Replaced to match accepted ApJ versio

De novo point mutations in patients diagnosed with ataxic cerebral palsy

Cerebral palsy is commonly attributed to perinatal asphyxia. However, Schnekenberg et al. describe here four individuals with ataxic cerebral palsy likely due to de novo dominant mutations associated with increased paternal age. Therefore, patients with cerebral palsy should be investigated for genetic causes before the disorder is ascribed to asphyxi