2,448 research outputs found

    A trichomycete-like fossil from the Triassic of Antarctica

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    Light converts endosymbiotic fungus to pathogen, influencing seedling survival and host tree recruitment

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    Endophytic fungi that asymptomatically colonize plants^1^ are diverse and abundant in tropical ecosystems^2^. These organisms can be weakly pathogenic^3^ and/or mutualistic, frequently enabling plants to adapt to extreme environments, alter competitive abilities of host individuals and improve host fitness under abiotic or biotic stresses^4,5,6^. _Diplodia mutila_ is a symbiotic endophyte/plant pathogenic fungus infecting the palm _Iriartea deltoidea_^7^, which dominates many wet lowland Neotropical forests. The fungus is an asymptomatic endophyte in mature plants, and disease and mortality are expressed in some seedlings, while others remain disease free. Here we show that seedlings bearing the endophyte show enhanced resistance to insect herbivory. However, high light availability triggers pathogenicity of the fungus, while low light favors endosymbiotic development, constraining recruitment of endophyte-infested seedlings to the shaded understory by limiting survival of seedlings in direct light. These results provide evidence that patterns of plant abundance and the mechanisms maintaining tropical forest biodiversity are the result of a more complex interplay between abiotic and biotic environments than previously thought

    Consumer Sensitivity to Interest Rates: An Empirical Study of New Car Buyers and Auto Loans

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    ALTHOUGH it has never been clear whether the consumer needs to be protected from his own folly or from the rapaciousness of those who feed on him, consumer protection is a topic of intense current interest in the courts, in the legislatures, and in the law schools. A number of recent court decisions have attempted to attack problems confronting the consumer; unfortunately, these judicial efforts have succeeded primarily in disclosing the limitations in the courts\u27 ability to deal with such problems. State and federal legislative bodies have pursued more carefully designed remedies. Congress has passed the Truth-in-Lending Act; the National Conference of Commissioners on Uniform State Laws has proposed the Uniform Consumer Credit Code; and many states have enacted retail installment sales acts to update and supplement their long-standing usury laws. These legisJative and judicial acts have always relied, at best, on anecdotal knowledge of consumer behavior. In this Article we offer the results of an empirical study of a small slice of consumer behavior in the use of installment credit

    A Trichomycete-like Fossil from the Triassic of Antarctica

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    Empirically-Based Warehouse Design: Can Academics Accept Such an Approach?

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    It is our opinion that existing research is not sufficient to support the design of a warehouse. As a result, facility designers that work in practice are left to face the design process with their own methods. These methods are in stark contrast to the analytical models developed in academia in that they are highly based on empirical observations. Supported by a collection of empirical observations, facility designers who work in practice employ an ad hoc design process. We present a design process based on empirical observations and then formalize it so that it can be taught and used. We illustrate the process with an example and discuss ways in which analytical methods can be used to supplement the process and improve the design. We conclude by describing additional work that is required if the design process is to be realized

    Tough Decisions: Defending the Homeland

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    Produced by WFYI, in partnership with the Indiana University School of Law - Indianapolis and the IU School of Public and Environmental Affairs. Tough Decisions: Defending the Homeland takes viewers behind-the-scenes at a groundbreaking simulation of terrorism event. The exercise forces a new generation of global leaders to develop innovative counter-terrorism tactics and strategies in order to disrupt terrorist activities, while restoring public safety and maintaining First Amendment rights. Viewable at https://iu.mediaspace.kaltura.com/media/Tough+Decision.mp4/1_slb6dra

    Palaeofibulus Gen. nov., a Clamp-Bearing Fungus from the Triassic of Antarctica

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    Spin-tunnel investigation of a 1/15-scale model of an Australian trainer airplane

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    An investigation was conducted in the Langley Spin Tunnel of the spin and spin-recovery characteristics of a 1/15-scale model of an Australian trainer airplane. The invesigation included erect and inverted spins; configuration variables such as a long tail, fuselage strakes, 20 deg. elevator cutouts, and rudder modifications; and determination of the parachute size for emergency spin recovery. Also included in the investigation were wing leading-edge modifications to evaluate Reynolds number effects. Results indicate that the basic configuration will spin erect at an angle of attack of about 63 deg. at about 2 to 2.3 seconds per turn. Recovery from this spin was unsatisfactory by rudder reversal or by rudder reversal and ailerons deflected to full with the spin. The elevators had a pronounced effect on the recovery characteristics. The elevators-down position was very adverse to recoveries, whereas the elevators-up position provided favorable recovery effects. Moving the vertical tail aft (producing a long tail configuration) improved the spin characteristics, but the recoveries were still considered marginal. An extension to the basic rudder chord and length made a significant improvement in the spin and recovery characteristics. Satisfactory recoveries were obtained by deflecting the rudder to full against the spin and the elevators and ailerons to neutral
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