106 research outputs found

    Agent-Based Modeling of Pollen Competition

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    Non-random mating in Arabidopsis Thaliana is, at least in part, due to intense competition between pollen grains to fertilize the limited number of ovules. Previous studies have pinpointed some of the competition traits that make pollen more or less competitive. Using these competition traits, we will build an agent-based computer model with NetLogo that simulates the competition between two accessions of Arabidopsis Thaliana pollen. This 2D model will allow the user to adjust pollen traits and competition strategies for each of the two pollen accessions. Some of the factors being considered include pollen viability, pollen tube growth rate, nutrients provided by the female, pollen tube attrition and the means of locating unfertilized ovules. To assess the competitiveness of the selected pollen traits, this model will track the number of fertilized ovules and maximum pollen tube length for each accession. This agent-based model will allow further study into the traits that make pollen most competitive as well as the strategies used by pollen to fertilize ovules. This model has the potential to quickly test a wide variety of competition traits and strategies without the need for in-lab experiments

    Agent-Based Modeling of Pollen Competition

    Get PDF
    Non-random mating in Arabidopsis Thaliana is, at least in part, due to intense competition between pollen grains to fertilize the limited number of ovules. Previous studies have pinpointed some of the competition traits that make pollen more or less competitive. Using these competition traits, we will build an agent-based computer model with NetLogo that simulates the competition between two accessions of Arabidopsis Thaliana pollen. This 2D model will allow the user to adjust pollen traits and competition strategies for each of the two pollen accessions. Some of the factors being considered include pollen viability, pollen tube growth rate, nutrients provided by the female, pollen tube attrition and the means of locating unfertilized ovules. To assess the competitiveness of the selected pollen traits, this model will track the number of fertilized ovules and maximum pollen tube length for each accession. This agent-based model will allow further study into the traits that make pollen most competitive as well as the strategies used by pollen to fertilize ovules. This model has the potential to quickly test a wide variety of competition traits and strategies without the need for in-lab experiments

    Computerizing Social-Emotional Assessment for School Readiness: First Steps toward an Assessment Battery for Early Childhood Settings

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    The transition into formal schooling is a crucial foundation that can set children on a cycle of success or failure in both academic and social domains. A child’s abilities to express healthy emotions, understand emotions of self and others, regulate emotion, attention, and behavior, make good decisions regarding social problems, and engage in a range of prosocial behaviors, all work together to promote a successful school experience. However, many children have deficits in these skills by school entry, and educators lack the requisite tools to identify, track and assess skills these children need to learn. Thus, because social-emotional learning (SEL) is so crucial, assessment tools to pinpoint children’s skills and progress are vitally necessary. Previous work by the authors and other researchers has led to the development of strong assessment tools; however, these tools are often developed solely for research use, not practitioner application. In the following, using our assessment battery as an example, we will discuss the steps necessary to adapt SEL assessment for computer-based administration and optimal utility in early childhood education programs

    Examining Factors Related to Teachers’ Decisions to Adopt Teacher-Training Resources for Inclusive Physical Education

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    Steps to Inclusion is a teacher-training resource specifically designed to facilitate inclusive physical education. Teacher-training resources, such as Steps to Inclusion, can only be effective when systematic and effective adoption is achieved. The diffusion of innovations theory (DOI) provides a useful framework to contextualize and understand factors related to teachers’ adoption of various teacher-training resources. Guided by the DOI, this study identified factors that teachers perceived to be important in facilitating resource adoption. Results indicate that improved adoption of resources could be achieved by: (a) communicating/promoting resources to key educational leaders, and (b) providing curated content. Additional practical implications and future directions are discussed. Keywords: inclusive education, physical education, students with disabilities, teacher trainingÉtapes vers l’inclusion est une ressource de formation pour enseignants conçue spécialement pour faciliter l’éducation physique inclusive. Les ressources pour la formation des enseignants telles qu’Étapes vers l’inclusion ne peuvent être efficaces que si l’adoption est systématique et effective. La théorie de la diffusion des innovations (diffusion of innovations [DOI]) fournit un cadre utile pour contextualiser et comprendre les facteurs liés à l’adoption par les enseignants de ressources de formation pour enseignants. Guidée par la DOI, cette étude a identifié les facteurs jugés importants par les enseignants pour faciliter l’adoption des ressources. Les résultats indiquent que l’adoption pourrait être améliorée en (a) communiquant / promouvant les ressources de formation des enseignants aux responsables de l’éducation et (b) en fournissant un contenu organisé. Des implications pratiques supplémentaires et des orientations futures sont également discutées. Mots-clés : éducation inclusive, éducation physique, étudiants handicapés, formation des enseignant

    Stability of spontaneous, correlated activity in mouse auditory cortex

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    Neural systems can be modeled as networks of functionally connected neural elements. The resulting network can be analyzed using mathematical tools from network science and graph theory to quantify the system's topological organization and to better understand its function. While the network-based approach is common in the analysis of large-scale neural systems probed by non-invasive neuroimaging, few studies have used network science to study the organization of networks reconstructed at the cellular level, and thus many very basic and fundamental questions remain unanswered. Here, we used two-photon calcium imaging to record spontaneous activity from the same set of cells in mouse auditory cortex over the course of several weeks. We reconstruct functional networks in which cells are linked to one another by edges weighted according to the correlation of their fluorescence traces. We show that the networks exhibit modular structure across multiple topological scales and that these multi-scale modules unfold as part of a hierarchy. We also show that, on average, network architecture becomes increasingly dissimilar over time, with similarity decaying monotonically with the distance (in time) between sessions. Finally, we show that a small fraction of cells maintain strongly-correlated activity over multiple days, forming a stable temporal core surrounded by a fluctuating and variable periphery. Our work provides a careful methodological blueprint for future studies of spontaneous activity measured by two-photon calcium imaging using cutting-edge computational methods and machine learning algorithms informed by explicit graphical models from network science. The methods are easily extended to additional datasets, opening the possibility of studying cellular level network organization of neural systems and how that organization is modulated by stimuli or altered in models of disease.Comment: 15 pages, 3 figure

    Y-12 National Security Complex Water Assessment

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    The Department of Energy's Federal Energy Management Program (FEMP) sponsored a water assessment at the Y-12 National Security Complex (Y 12) located in Oak Ridge, Tennessee. Driven by mandated water reduction goals of Executive Orders 13423 and 13514, the objective of the water assessment is to develop a comprehensive understanding of the current water-consuming applications and equipment at Y-12 and to identify key areas for water efficiency improvements that could be applied not only at Y-12 but at other Federal facilities as well. FEMP selected Pacific Northwest National Laboratory to coordinate and manage the water assessment. PNNL contracted Water Savers, LLC to lead the technical aspects of the water assessment. Water Savers provided key technical expertise in water auditing, metering, and cooling systems. This is the report of that effort, which concluded that the Y-12 facility could realize considerable water savings by implementing the recommended water efficiency opportunities

    Evaluation of EPAS1 variants for association with bovine congestive heart failure [version 1; peer review: 2 approved]

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    Background: Bovine congestive heart failure (BCHF) has become increasingly prevalent in feedlot cattle in the Western Great Plains of North America. BCHF is an untreatable complex condition involving pulmonary hypertension that culminates in right ventricular failure and death. A protein variant of hypoxia-inducible factor 2 alpha (HIF2α, encoded by the endothelial PAS domain-containing protein 1 gene, EPAS1) was previously reported to be associated with pulmonary hypertension at altitudes exceeding 2,000 m. Our aim was to evaluate EPAS1 haplotypes for association with BCHF in feedlot cattle raised at moderate altitudes (1,200 m). Methods: Paired samples of clinical cases and unaffected controls were collected at four feedlots in Nebraska and Wyoming. Each pair (n =102) was matched for source, pen, breed type, sex, arrival date, and management conditions. Cases were identified by animal caretakers, euthanized, and diagnosis was confirmed at necropsy. Cases were derived from 30 different ranch operations, with the largest source contributing 32. Animals were tested for eight EPAS1 haplotypes encoding 36 possible different diploid combinations. Results: The common, ancestral EPAS1 haplotype encoding HIF2α with alanine (A) at position 606 and glycine (G) at position 610 was equally frequent in cases and controls (0.67). The EPAS1 variant haplotype reported to be associated with disease (encoding threonine (T) at position 606 and serine (S) at position 610) was not enriched in cases compared with controls (0.21 and 0.25, respectively). Frequencies of other EPAS1 haplotypes (e.g., encoding Q270, L362, or G671) were each less than 0.05 overall. McNemar’s test with 45 discordant pairs showed the linked T606/S610 variant was not associated with BCHF (OR = 0.73, CI 0.38 -1.4, p-value = 0.37). Conclusions: HIF2α polypeptide variants were not significantly associated with BCHF in feedlot cattle at moderate altitudes. Thus, a wider search is needed to identify genetic risk factors underlying this disease

    Extended inverse-Compton emission from distant, powerful radio galaxies

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    We present Chandra observations of two relatively high redshift FR II radio galaxies, 3C 432 and 3C 191 (z = 1.785 and 1.956, respectively), both of which show extended X-ray emission along the axis of the radio jet or lobe. This X-ray emission is most likely to be due to inverse-Compton scattering of cosmic microwave background (CMB) photons. Under this assumption, we estimate the minimum energy contained in the particles responsible. This can be extrapolated to determine a rough estimate of the total energy. We also present new, deep radio observations of 3C 294, which confirm some association between radio and X-ray emission along the north-east-south-west radio axis and also that radio emission is not detected over the rest of the extent of the diffuse X-ray emission. This together with the offset between the peaks of the X-ray and radio emissions may indicate that the jet axis in this source is precessing
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