Isolation of Metrosideros ('Ohi'a) Taxa on O'ahu Increases with Elevation and Extreme Environments.

Species radiations should be facilitated by short generation times and limited dispersal among discontinuous populations. Hawaii's hyper-diverse, landscape-dominant tree, Metrosideros, is unique among the islands' radiations for its massive populations that occur continuously over space and time within islands, its exceptional capacity for gene flow by both pollen and seed, and its extended life span (ca. >650 years).

Feasibility of using neural networks to estimate minimum tumour temperature and perfusion values.

We examine the ability of neural networks to estimate the tissue perfusion values present and the minimum temperature in numerically calculated (Pennes, Bioheat Transfer Equation) steady-state hyperthermia temperature fields based on a limited number of measured temperatures within this field A hierarchical system of neural networks consisting of a first layer of pattern recognizing neural networks and a second layer of hypersurface reconstructing neural networks is shown to be capable of estimating these variables within a selected error tolerance. The results indicate that estimating the minimum tumour temperature directly with the system of neural networks may be more effective than using the indirect method of numerically recreating a temperature field with perfusion estimates and then obtaining the minimum tumour temperature from the estimated temperature field. Additional results indicate that if the locations of the measured temperatures within the temperature field are selected appropriately, the hierarchical system of neural networks can tolerate a moderate level of model mismatch.

Concurrent hyperthermia estimation schemes based on extended Kalman filtering and reduced-order modelling.

The success of treating cancerous tissue with heat depends on the temperature elevation, the amount of tissue elevated to that temperature, and the length of time that the tissue temperature is elevated. In clinical situations the temperature of most of the treated tissue volume is unknown, because only a small number of temperature sensors can be inserted into the tissue. A state space model based on a finite difference approximation of the bioheat transfer equation (BHTE) is developed for identification purposes.

Application of multiple modelling to hyperthermia estimation: reducing the effects of model mismatch.

Multiple model estimation is a viable technique for dealing with the spatial perfusion model mismatch associated with hyperthermia dosimetry. Using multiple models, spatial discrimination can be obtained without increasing the number of unknown perfusion zones. Two multiple model estimators based on the extended Kalman filter (EKF) are designed and compared with two EKFs based on single models having greater perfusion zone segmentation.

Analytical study of temperature oscillations in living tissues.

A nonlinear, time-delay differential equation is postulated as a possible structure to describe the temperature dynamics at a point inside living tissue. The presented analysis explains how this differential equation can lead to four different temperature response types that have been previously observed in vivo.