Richard K. Kobe

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Four-quadrature spectral interferometry using balanced coherent detection enables single-shot full-field characterization of complex-shaped optical waveforms with near quantum-limited sensitivity. A 90° optical hybrid places a waveform in four-quadrature-phases with a stronger, well-characterized reference pulse. Measurement of the four spectra with an(More)
The generation of high-repetition-rate optical frequency combs with an ultra-broad, coherent and smooth spectrum is important for many applications in optical communications, radio-frequency photonics and optical arbitrary waveform generation. Usually, nonlinear broadening techniques of comb-based sources do not provide the required flatness over the whole(More)
Plants that store nonstructural carbohydrates (NSC) may rely on carbon reserves to survive carbon-limiting stress, assuming that reserves can be mobilized. We asked whether carbon reserves decrease in resource stressed seedlings, and if NSC allocation is related to species' relative stress tolerances. We tested the effects of stress (shade, drought, and(More)
Although one of the most widely studied hypotheses for high tree diversity in the tropics, the Janzen–Connell hypothesis (JC), and the community compensatory trend upon which it is based, have conflicting support from prior studies. Some of this variation could arise from temporal variation in seedling survival of common and rare species. Using 10 years of(More)
The relative benefits that mycorrhizal fungi confer to host plants and reforestation efforts may differ due to the host tree species and soil nutrient status. Our research objective was to examine the effects of mycorrhizal fungi, host tree species, and soil nutrient availability on nutrient acquisition in tropical reforestation. Four tree species (Pinus(More)
In closed-canopy forests, gap formation and closure are thought to be major drivers of forest dynamics. Crown defoliation by insects, however, may also influence understory resource levels and thus forest dynamics. We evaluate the effect of a forest tent caterpillar outbreak on understory light availability, soil nutrient levels and tree seedling height(More)
Experiments with plant species that can host both arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) are important to separating the roles of fungal type and plant species and understanding the influence of the types of symbioses on plant growth and nutrient acquisition. We examined the effects of mycorrhizal fungal type on the growth and(More)
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