231 research outputs found

    A preliminary systems study of interface equipment for digitally programmed flight simulators

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    Design study of digitally programmed supersonic transport flight simulato

    Guidance of neuronal growth cones in the grasshopper embryo. I. Recognition of a specific axonal pathway by the pCC neuron

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    Journal ArticleThe selective affinities that growth cones display for specific axonal surfaces give rise to stereotyped patterns of selective fasciculation. Previous studies on cell recognition by neuronal growth cones in the grasshopper embryo led to the proposal and initial experimental testing of the labeled-pathways hypothesis

    Guidance of neuronal growth cones in the grasshopper embryo. II. Recognition of a specific axonal pathway by the aCC neuron

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    Journal ArticleIn the previous paper, we experimentally analyzed the selective affinity of the pCC growth cone for the MP1/dMP2 fascicle in the grasshopper embryo. Here we describe a similar experimental analysis demonstrating the selective affinity of the aCC growth cone for the U fascicle. These results support the labeled-pathways hypothesis

    Predicting the dynamics and heterogeneity of genomic DNA content within bacterial populations across variable growth regimes

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    For many applications in microbial synthetic biology, optimizing a desired function requires careful tuning of the degree to which various genes are expressed. One challenge for predicting such effects or interpreting typical characterization experiments is that in bacteria such as E. coli, genome copy number varies widely across different phases and rates of growth, which also impacts how and when genes are expressed from different loci. While such phenomena are relatively well-understood at a mechanistic level, our quantitative understanding of such processes is essentially limited to ideal exponential growth. In contrast, common experimental phenomena such as growth on heterogeneous media, metabolic adaptation, and oxygen restriction all cause substantial deviations from ideal exponential growth, particularly as cultures approach the higher densities at which industrial biomanufacturing and even routine screening experiments are conducted. To meet the need for predicting and explaining how gene dosage impacts cellular functions outside of exponential growth, we here report a novel modeling strategy that leverages agent-based simulation and high performance computing to robustly predict the dynamics and heterogeneity of genomic DNA content within bacterial populations across variable growth regimes. We show that by feeding routine experimental data, such as optical density time series, into our heterogeneous multiphasic growth simulator, we can predict genomic DNA distributions over a range of nonexponential growth conditions. This modeling strategy provides an important advance in the ability of synthetic biologists to evaluate the role of genomic DNA content and heterogeneity in affecting the performance of existing or engineered microbial functions

    MODELING OF HYDROTHERMAL FLUID CIRCULATION AS A TOOL FOR VOLCANIC HAZARD ASSESSMENT

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    Monitoring of geophysical and geochemical observ¬ables at the surface plays a main role in the under¬standing of—and the hazard evaluation of— active volcanoes. Measurable changes in these parameters should occur when a volcano approches eruptive con¬ditions. Hydrothermal activity is commonly studied as an efficient carrier of signals from the magmatic system. As the magmatic system evolves, the amount, temperature, and composition of magmatic fluids that feed the hydrothermal system change, in turn affecting the parameters that are monitored at the surface. Modeling of hydrothermal circulation, as shown in the past, may cause measurable gravity changes and ground deformation. In this work, we extend our previous studies and increase the number of observable parameters to include gas temperature, the rate of diffuse degassing, the extent of the degassing area, and electrical conductivity. The possibility of nonmagmatic disturbance needs to be carefully addressed to ensure a proper estimate of volcanic hazard

    Water Resources of the Fond du Lac Indian Reservation, East-Central Minnesota

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    Saint Paul, MN: USGS.This interesting report presents the findings of a hydrologic study of the Fond du Lac Indian Reservation. The study is the outcome of a 1978 Federal mandate to the Bureau of Indian Affairs to review Indian water-rights claims in reservations throughout the United States. The Fond du Lac Indian Reservation study, done by the U. S. Geological Survey in cooperation with the Fond du Lac Indian Reservation Business Committee, is the first of the these studies undertaken in Minnesota under the Federal mandate. The report notes that ground water resources derive from three aquafers, and that surface waters derive from wetlands and surficial waters within the St. Louis River watershed. Except for a small number of well-water samples, water quality was found to be within EPA limits for pollutants and was determined to be safe for human and animal consumption. A few wells had elevated levels of lead and manganese; four principal streams contained E. coli and Streptococcus

    AGATHE: A tool for personalized rehabilitation of cognitive functions

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    Stroke, traumatic brain injury, multiple sclerosis, Parkinson's disease, Alzheimer's... Every year in France, tens of thousands of people fall victim to one of those neurological pathologies. Acquired brain injury leads to cognitive impairment and heavy loss of autonomy. Rehabilitation interventions are needed to enable people to recover capacity and return to Activities of Daily Living (ADL), such as grocery shopping. Unfortunately, the resources made available in cognitive rehabilitation are insufficient for the growing needs of victims of brain damage. The assets of virtual reality to address this big problem of public health are today scientifically recognized [Rizzo and Kim 2005; Klinger, et al. 2010]. In this context, we designed the AGATHE tool (Adaptable, configurable and upgradable tool for the generation of personalized therapeutic applications in cognitive rehabilitation) (AGATHE project, ANR-09-TECS-002).French National Research Agency (ANR) Laval Agglomération et Conseil Général de la Mayenn

    Control Architecture Concepts and Properties of an Ontology Devoted to Exchanges in Mobile Robotics

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    National audienceA specific ontology is proposed in the scope of the development of a platform devoted to exchanges between academics and industrials of the robotic domain. This paper presents the tools used for knowledge elicitation, the concepts and properties linked with control architecture, the use of the resulting ontology for description of some scenarios and the tracks for the development of a domain specific language grounded on the ontology. Knowledge elicitation is performed in web ontology language thanks to Protégé ontology editor. The ontology is structured as a set of modules organized around a kernel. Modules addressing systems, information, robot and mission include concepts and properties for control architecture description. The expressivity of the ontology is demonstrated describing architectures for a set of scenarios; urban robotic scenario, air-ground scenario, landmark search scenario and military unmanned aerial vehicles scenario. Finally some tracks for the use of the ontology for developing a domain specific language are given

    AGATHE: A tool for personalized rehabilitation of cognitive functions

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    Stroke, traumatic brain injury, multiple sclerosis, Parkinson's disease, Alzheimer's... Every year in France, tens of thousands of people fall victim to one of those neurological pathologies. Acquired brain injury leads to cognitive impairment and heavy loss of autonomy. Rehabilitation interventions are needed to enable people to recover capacity and return to Activities of Daily Living (ADL), such as grocery shopping. Unfortunately, the resources made available in cognitive rehabilitation are insufficient for the growing needs of victims of brain damage. The assets of virtual reality to address this big problem of public health are today scientifically recognized [Rizzo and Kim 2005; Klinger, et al. 2010]. In this context, we designed the AGATHE tool (Adaptable, configurable and upgradable tool for the generation of personalized therapeutic applications in cognitive rehabilitation) (AGATHE project, ANR-09-TECS-002).French National Research Agency (ANR) Laval Agglomération et Conseil Général de la Mayenn

    Growth cone guidance in the zebrafish central nervous system

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    The accessibility and simplicity of the zebrafish embryo have allowed researchers to make a detailed characterization of pathfinding by identifiable growth cones. The growth cones follow precise cell-specific pathways to their targets. Analyses of pathfinding in mutant and experimentally manipulated wild type embryos have shown that growth cones accomplish this by interacting with specific cellular cues in their environment, many of which are likely to be redundant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30213/1/0000603.pd
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