14,603 research outputs found

    The Nature of Succession

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    Sensitive plant (Mimosa pudica) hiding time depends on individual and state.

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    The decisions animals make to adjust their antipredator behavior to rapidly changing conditions have been well studied. Inducible defenses in plants are an antipredator behavior that acts on a longer time scale, but sensitive plants, Mimosa pudica, have a much more rapid antipredator response; they temporarily close their leaves when touched. The time they remain closed is defined as hiding time. We studied hiding time in sensitive plants and found that individual plants differed significantly in their hiding times. We then showed that the effect of individual explained substantial variation in hiding time on a short time scale. Finally, on a longer time scale, individuality persisted but the amount of variation attributed to individual decreased. We hypothesized that variation in plant condition might explain this change. We therefore manipulated sunlight availability and quantified hiding time. When deprived of light for 6 h, sensitive plants significantly shortened their hiding times. But when only half a plant was deprived of light, hiding times on the deprived half and light exposed half were not significantly different. This suggests that overall condition best explains variation in sensitive plant antipredator behavior. Just like in animals, sensitive plant antipredator behavior is condition dependent, and, just like in animals, a substantial amount of the remaining variation is explained by individual differences between plants. Thus, models designed to predict plasticity in animal behavior may be successfully applied to understand behavior in other organisms, including plants

    R/C Baja: Drivetrain

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    The Central Washington University Mechanical Engineering Technology Department hosts an annual R/C Baja competition in which R/C cars fabricated by student teams are put through a series of courses and tests to determine which team\u27s vehicle is best. The goal of this project was to create a functioning drivetrain that conveys power from the battery to the wheels and provides control of the vehicle. A list of requirements for the drivetrain was created to ensure that the vehicle will not only function, but that it will actually succeed in the competition. These requirements included that the vehicle must achieve a maximum speed that exceeds 20 mph and retain the capacity to produce maximum power for more than 15 minutes. To achieve this, preliminary calculations were completed that utilized principles from kinematics, basic electricity and mechanics of materials to ensure that these requirements would be met. Following this, 3D models and assemblies of the drivetrain and vehicle were produced. These steps culminated in the construction of the vehicle which utilized multiple construction methods such as machining and 3D printing. The finalized vehicle performed as intended with its maximum speed exceeding 20 mph and retained the capacity to produce maximum power in excess of 30 minutes
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