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Broadband synthetics obtained from scenario simulations of earthquakes with a frequency content between 0 and 10 Hz, referred to hereafter as “BBSs,” are playing an increasingly important role in seismic hazard analysis. An example is the Great Southern California ShakeOut, the largest disaster response exercise in U.S. history and an annual event since 2008 (Jones et al. 2008). The drill was the first to be based on BBSs, in this case for an M 7.8 scenario earthquake on the southern San Andreas fault. Another example of the important role of synthetic ground motions is the increasing awareness of the advantages of using site-specific ground-motion time series, rather than empirical intensity measures or scaled time series from different sources or locations, for more realistic non-linear dynamic analysis of buildings and performance-based earthquake engineering. BBSs appear to be one of the only viable alternatives to the very limited amount of strong-motion time series, particularly in the near-field from large earthquakes. Effectively meeting demands of this sort for realistic BBSs requires careful validation against recorded data. BBSs are currently achieved by combining deterministic low-frequency (LF) synthetics up to a maximum frequency ( fmax) of typically 1–2 Hz with high-frequency (HF) stochastic synthetics above this upper cutoff frequency (see, for example, Graves and Pitarka 2004; Liu et al. 2006; Mai et al. forthcoming). Visual inspection has been used for decades to claim success or failure of the ability of simulations to match observations (or synthetics derived from an alternative numerical method). However, at shorter periods such visual waveform fits are not practical, likely due to chaotic source and path variability. For example, specific intensity measures tend to be more practical and relevant than actual waveform fits at higher frequencies. Candidates for metrics to measure the misfit for BBSs include commonly used ground-motion intensity …

This paper proposes a new reconstruction method for diffuse optical tomography using reduced-order models of light transport in tissue. The models, which directly map optical tissue parameters to optical flux measurements at the detector locations, are derived based on data generated by numerical simulation of a reference model. The reconstruction algorithm based on the reduced-order models is a few orders of magnitude faster than the one based on a finite element approximation on a fine mesh incorporating a priori anatomical information acquired by magnetic resonance imaging. We demonstrate the accuracy and speed of the approach using a phantom experiment and through numerical simulation of brain activation in a rat's head. The applicability of the approach for real-time monitoring of brain hemodynamics is demonstrated through a hypercapnic experiment. We show that our results agree with the expected physiological changes and with results of a similar experimental study. However, by using our approach, a three-dimensional tomographic reconstruction can be performed in ∼3 s per time point instead of the 1 to 2 h it takes when using the conventional finite element modeling approach.

The different silvicultural techniques for establishing big-leaf mahogany plantations have been well documented, but these methods frequently take little account of the long-term development of stands or subsequent rotations and cannot properly be called silvicultural systems. As existing plantations begin to mature, the need to consider establishing the next rotation grows, and, therefore, the need to adopt a suitable silvicultural system. Where plantations of big-leaf mahogany have begun to regenerate naturally, the traditional system of clear-cutting and replanting may not be appropriate. Natural regeneration has the advantages of reducing nursery and establishment costs and possibly the extent of damage by shoot borer (Hypsipyla sp.). Early attempts to apply a single tree selection system to big-leaf mahogany plantations were unsuccessful, but recent plans to adopt a modified uniform shelterwood system in Sri Lanka and a group selection system in St. Lucia have been more carefully developed. The proposed systems are described in detail. Successful long-term management of big-leaf mahogany plantations depends on choosing a system that accommodates both the light requirements of the species and key local constraints under which plantation managers are operating. Local constraints should be carefully considered before a silvicultural system is adopted.