Christopher K. Boyce

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Contrary to what might be expected from the observation of extant plants alone, the fossil record indicates that most aspects of vascular plant form evolved multiple times during their Paleozoic radiation. Opportunity is increasing to unite information from fossil and living plants to understand the evolution of developmental mechanisms and each field can(More)
The popularity of the iris biometric has grown considerably over the past two to three years. Most research has been focused on the development of new iris processing and recognition algorithms for frontal view iris images. However, a few challenging directions in iris research have been identified, including processing of a nonideal iris and iris at a(More)
Angiosperm leaves manifest a remarkable diversity of shapes that range from developmental sequences within a shoot and within crown response to microenvironment to variation among species within and between communities and among orders or families. It is generally assumed that because photosynthetic leaves are critical to plant growth and survival,(More)
Multispectral Iris Recognition Analysis: Techniques and Evaluation This thesis explores the benefits of using multispectral iris information acquired using a narrow-band multispectral imaging system. Commercial iris recognition systems typically sense the iridal reflection pertaining to the near-infrared (IR) range of the electromagnetic spectrum. While(More)
[1] Tropical rainforests are known to exhibit low intrasea-sonal precipitation variability compared with oceanic areas with similar mean precipitation in observations and models. In the present study, the potential role of transpiration for this difference in precipitation variability is investigated using the National Center for Atmospheric Research (NCAR)(More)
The geological durations of species in our analysis, from the base of the stage of first appearance to the top of the stage of last appearance, vary from 2.0 to 32 My, with a median [±1 SE (SOM)] of 8.7 ± 0.4 My (27). Median durations are 9.3 ± 0.4 My for the shaded species in Fig. 1, and 8.3 ± 0.4 for the remaining species. The median time taken to attain(More)
resolution ab initio three-dimensional x-ray diffraction microscopy, " J. Reconstruction of a yeast cell from x-ray diffraction data, " Acta Cryst. A (accepted). Apparatus for X-ray diffraction microscopy and tomography of cryo specimens. Advantages of soft X-ray absorption over TEM-EELS for solid carbon studies-a comparative study on diesel soot with EELS(More)
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