236 research outputs found

    The Function and Organization of the Motor System Controlling Flight Maneuvers in Flies

    Get PDF
    Animals face the daunting task of controlling their limbs using a small set of highly constrained actuators. This problem is particularly demanding for insects such as Drosophila, which must adjust wing motion for both quick voluntary maneuvers and slow compensatory reflexes using only a dozen pairs of muscles. To identify strategies by which animals execute precise actions using sparse motor networks, we imaged the activity of a complete ensemble of wing control muscles in intact, flying flies. Our experiments uncovered a remarkably efficient logic in which each of the four skeletal elements at the base of the wing are equipped with both large phasically active muscles capable of executing large changes and smaller tonically active muscles specialized for continuous fine-scaled adjustments. Based on the responses to a broad panel of visual motion stimuli, we have developed a model by which the motor array regulates aerodynamically functional features of wing motion

    Nutritive Levels in Plants from Stripmined Areas in Eastern Ohio

    Get PDF
    Author Institution: Ohio Cooperative Wildlife Research Unit, The Ohio State UniversityData on nutritive quality of vegetation for stripmined lands were obtained in 1972-73 from 2 Ohio counties, one having generally acidic spoil banks and the other having calcareous spoils. Proximate analysis of water, ash, crude protein, ether extract, cell-wall constituents, and nitrogen-free extract revealed few significant differences between plants growing on stripped and undisturbed (control) plots. Plants also were analyzed for 6 essential elements by emission spectrography. Levels of potassium were significantly higher in plants from control plots. Calcium levels were higher in plants from alkaline spoils, and manganese levels were higher in plants from acidic mined plots. Manganese levels exceeded 600 ppm in some plant samples from acidic spoil banks. Even when plants from stripped plots contained significantly less of a given element, levels were generally not low enough to indicate nutrient deficiency

    TEACHER COLLABORATIVE INQUIRY IN ONTARIO ELEMENTARY SCHOOLS: AN ANALYSIS OF PROVINCIAL AND SCHOOL BOARD POLICIES AND SUPPORT DOCUMENTS

    Get PDF
    Collaborative inquiry (CI) has emerged as a dominant structure for educators’ professional learning in the 21st century. The purpose of this paper is to analyze publicly available documents and policies related to CI in Ontario in order to better understand the documentary scope and spread of this professional learning model in the province. We begin by defining the parameters of CI as a dominant professional learning model before detailing our methodology for selecting and analyzing CI policies and documents at both ministry and school board levels. In our subsequent analysis, we enumerate emergent themes and findings and offer three sample case studies that illustrate how school boards in the province are documenting their experiences with CI. Finally, we conclude with a discussion of potential tensions within current CI policies as a basis for future research and policy development.

    The Function and Organization of the Motor System Controlling Flight Maneuvers in Flies

    Get PDF
    Animals face the daunting task of controlling their limbs using a small set of highly constrained actuators. This problem is particularly demanding for insects such as Drosophila, which must adjust wing motion for both quick voluntary maneuvers and slow compensatory reflexes using only a dozen pairs of muscles. To identify strategies by which animals execute precise actions using sparse motor networks, we imaged the activity of a complete ensemble of wing control muscles in intact, flying flies. Our experiments uncovered a remarkably efficient logic in which each of the four skeletal elements at the base of the wing are equipped with both large phasically active muscles capable of executing large changes and smaller tonically active muscles specialized for continuous fine-scaled adjustments. Based on the responses to a broad panel of visual motion stimuli, we have developed a model by which the motor array regulates aerodynamically functional features of wing motion

    Multifunctional Wing Motor Control of Song and Flight

    Get PDF
    Multifunctional motor systems produce distinct output patterns that are dependent on behavioral context, posing a challenge to underlying neuronal control. Flies use their wings for flight and the production of a patterned acoustic signal, the male courtship song, employing in both cases a small set of wing muscles and corresponding motor neurons. We took first steps toward elucidating the neuronal control mechanisms of this multifunctional motor system by live imaging of muscle ensemble activity patterns during song and flight, and we established the functional role of a comprehensive set of wing muscle motor neurons by silencing experiments. Song and flight rely on distinct configurations of neuromuscular activity, with most, but not all, flight muscles and their corresponding motor neurons contributing to song and shaping its acoustic parameters. The two behaviors are exclusive, and the neuronal command for flight overrides the command for song. The neuromodulator octopamine is a candidate for selectively stabilizing flight, but not song motor patterns

    Splink: Free software for probabilistic record linkage at scale.

    Get PDF
    Funded by ADR UK, a new data linking team at the Ministry of Justice set out to link administrative datasets across the justice space, for internal use and sharing with external researchers. To achieve this aim we sought a linkage implementation that was probabilistic, flexible, scalable and ideally open source. Taking into account the tools available at the MoJ, existing open-source software (and paid alternatives) failed to meet our desired criteria. It was decided to develop a software package that builds on FastLink’s implementation in R of an Expectation-Maximisation algorithm to estimate a Fellegi-Sunter linkage model, adding a range of technical improvements, increased functionality and customisation options. Distributed computing offered by Spark could facilitate comparable linkage jobs that run on much larger datasets and much faster. Working with government data, accountability and transparency are vital, so the data and models are made accessible by a range of intuitive visualizations. The Splink python package has been downloaded 2 million times. This initially used Spark to deliver its superior performance, but Splink v3 caters for various SQL backends and more potential users. Splink and supplementary python libraries are publicly visible on GitHub and provide assistance in all aspects of data linkage: - splink_data_standardisation - functions to perform general data standardisation - splink_cluster_studio - creates an interactive HTML dashboard to analyse record clusters (building on splink_graph - a library for generating graph metrics) - splink_synthetic_data - generating realistic synthetic data for testing linkage algorithms - splink_demos - interactive demo/tutorial notebooks for a range of features of the Splink libraries These tools are in continuous development and have already been used to deliver deduplicated and linked data products for the entire criminal justice system. Through technical innovation and user-focused development, Splink has improved access to cutting-edge data linkage, and created groundbreaking research opportunities at MoJ and beyond. The team is grateful to ONS and other collaborators for testing and adopting these tools, and will continue to explore ways to improve performance and user experience

    A stochastic neuronal model predicts random search behaviors at multiple spatial scales in C. elegans

    Get PDF
    Random search is a behavioral strategy used by organisms from bacteria to humans to locate food that is randomly distributed and undetectable at a distance. We investigated this behavior in the nematode Caenorhabditis elegans, an organism with a small, well-described nervous system. Here we formulate a mathematical model of random search abstracted from the C. elegans connectome and fit to a large-scale kinematic analysis of C. elegans behavior at submicron resolution. The model predicts behavioral effects of neuronal ablations and genetic perturbations, as well as unexpected aspects of wild type behavior. The predictive success of the model indicates that random search in C. elegans can be understood in terms of a neuronal flip-flop circuit involving reciprocal inhibition between two populations of stochastic neurons. Our findings establish a unified theoretical framework for understanding C. elegans locomotion and a testable neuronal model of random search that can be applied to other organisms
    • …
    corecore