18 research outputs found

    Rates of distress vocalizations in naive domestic chicks as an index of approach tendency to an imprinting stimulus

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    Naive chicks were exposed to an imprinting target, consisting of a bank of miniature flashing lights, under normal (100[deg]F) and reduced temperatures (75 and 57[deg]F). It was found that cold reliably evoked distress calls and that the cyclic presentations of the target substantially reduced distress calling when the target was present, relative to when it was absent. When later tested for approach tendencies to the target, clear differences between temperature groups did not emerge. Evidence was obtained, however, that chicks that showed the greatest reduction in distress calling in response to the presentation of the target under the cold conditions showed significantly greater approach tendencies in the subsequent tests.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33786/1/0000041.pd

    Predicting solar cell performance from terahertz and microwave spectroscopy

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    Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current-voltage characteristics of a solar cell from such measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter-laboratory variations are discussed using a (Cs,FA,MA)Pb(I,Br)3 halide perovskite thin-film as a case study. At 1 sun equivalent excitation, neither transport nor recombination is significantly affected by exciton formation or trapping. Terahertz, microwave, and photoluminescence transients for the neat material yield consistent effective lifetimes implying a resistance-free JV-curve with a potential power conversion efficiency of 24.6 %. For grainsizes above ≈20 nm, intra-grain charge transport is characterized by terahertz sum mobilities of ≈32 cm2 V−1 s−1. Drift-diffusion simulations indicate that these intra-grain mobilities can slightly reduce the fill factor of perovskite solar cells to 0.82, in accordance with the best-realized devices in the literature. Beyond perovskites, this work can guide a highly predictive characterization of any emerging semiconductor for photovoltaic or photoelectrochemical energy conversion. A best practice for the interpretation of terahertz and microwave measurements on photovoltaic materials is presented

    A Comparative Study Of Behavior Change And Preschool Intervention.

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    PhDPsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/189656/2/7324583.pd
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