Geological image processing of petrographic thin sections using the rotating polarizer stage

One of the fundamental problems with image processing of petrographic thin sections is that the appearance (colour I intensity) of a mineral grain will vary with the orientation of the crystal lattice to the preferred direction of the polarizing filters on a petrographic microscope. This makes it very difficult to determine grain boundaries, grain orientation and mineral species from a single captured image. To overcome this problem, the Rotating Polarizer Stage was used to replace the fixed polarizer and analyzer on a standard petrographic microscope. The Rotating Polarizer Stage rotates the polarizers while the thin section remains stationary, allowing for better data gathering possibilities. Instead of capturing a single image of a thin section, six composite data sets are created by rotating the polarizers through 900 (or 1800 if quartz c-axes measurements need to be taken) in both plane and cross polarized light. The composite data sets can be viewed as separate images and consist of the average intensity image, the maximum intensity image, the minimum intensity image, the maximum position image, the minimum position image and the gradient image. The overall strategy used by the image processing system is to gather the composite data sets, determine the grain boundaries using the gradient image, classify the different mineral species present using the minimum and maximum intensity images and then perform measurements of grain shape and, where possible, partial crystallographic orientation using the maximum intensity and maximum position images.

Quadtree representation and compression of spatial data

Spatial data representation and compression has become a focus issue in computer graphics and image processing applications. Quadtrees, as one of hierarchical data structures, basing on the principle of recursive decomposition of space, always offer a compact and efficient representation of an image. For a given image, the choice of quadtree root node plays an important role in its quadtree representation and final data compression. The goal of this thesis is to present a heuristic algorithm for finding a root node of a region quadtree, which is able to reduce the number of leaf nodes when compared with the standard quadtree decomposition. The empirical results indicate that, this proposed algorithm has quadtree representation and data compression improvement when in comparison with the traditional method.

Sleep and information processing in individuals who have sustained a traumatic brain injury

Individuals who have sustained a traumatic brain injury (TBI) often complain of t roubl e sleeping and daytime fatigue but little is known about the neurophysiological underpinnings of the s e sleep difficulties. The fragile sleep of thos e with a TBI was predicted to be characterized by impairments in gating, hyperarousal and a breakdown in sleep homeostatic mechanisms. To test these hypotheses, 20 individuals with a TBI (18- 64 years old, 10 men) and 20 age-matched controls (18-61 years old, 9 men) took part in a comprehensive investigation of their sleep. While TBI participants were not recruited based on sleep complaint, the fmal sample was comprised of individuals with a variety of sleep complaints, across a range of injury severities. Rigorous screening procedures were used to reduce potential confounds (e.g., medication). Sleep and waking data were recorded with a 20-channel montage on three consecutive nights. Results showed dysregulation in sleep/wake mechanisms. The sleep of individuals with a TBI was less efficient than that of controls, as measured by sleep architecture variables. There was a clear breakdown in both spontaneous and evoked K-complexes in those with a TBI. Greater injury severities were associated with reductions in spindle density, though sleep spindles in slow wave sleep were longer for individuals with TBI than controls. Quantitative EEG revealed an impairment in sleep homeostatic mechanisms during sleep in the TBI group. As well, results showed the presence of hyper arousal based on quantitative EEG during sleep. In wakefulness, quantitative EEG showed a clear dissociation in arousal level between TBls with complaints of insomnia and TBls with daytime fatigue. In addition, ERPs indicated that the experience of hyper arousal in persons with a TBI was supported by neural evidence, particularly in wakefulness and Stage 2 sleep, and especially for those with insomnia symptoms. ERPs during sleep suggested that individuals with a TBI experienced impairments in information processing and sensory gating. Whereas neuropsychological testing and subjective data confirmed predicted deficits in the waking function of those with a TBI, particularly for those with more severe injuries, there were few group differences on laboratory computer-based tasks. Finally, the use of correlation analyses confirmed distinct sleep-wake relationships for each group. In sum, the mechanisms contributing to sleep disruption in TBI are particular to this condition, and unique neurobiological mechanisms predict the experience of insomnia versus daytime fatigue following a TBI. An understanding of how sleep becomes disrupted after a TBI is important to directing future research and neurorehabilitation.

Power, Contextual Intelligence and Leadership: Research Approaches for Understanding Participatory Community Climate Change Adaptation

Analysis of power in natural resources management is important as multiple stakeholders interact within complex, social-ecological systems. As a sub-set of these interactions, community climate change adaptation is increasingly using participatory processes to address issues of local concern. While some attention has been paid to power relations in this respect, e.g. evaluating international climate regimes or assessing vulnerability as part of integrated impact assessments, little attention has been paid to how a structured assessment of power could facilitate real adaptation and increase the potential for successful participatory processes. This paper surveys how the concept of power is currently being applied in natural resources management and links these ideas to agency and leadership for climate change adaptation. By exploring behavioural research on destructive leadership, a model is developed for informing participatory climate change adaptation. The working paper then concludes with a discussion of developing research questions in two specific areas - examining barriers to adaptation and mapping the evolution of specific participatory processes for climate change adaptation.

Morphonotactic and phonotactic processing in German-speaking adults

Based on the theoretical framework of Dressler and Dziubalska-Kołaczyk (2006a,b), the Strong Morphonotactic Hypothesis will be tested. It assumes that phonotactics helps in decomposition of words into morphemes: if a certain sequence occurs only or only by default over a morpheme boundary and is thus a prototypical morphonotactic sequence, it should be processed faster and more accurately than a purely phonotactic sequence. Studies on typical and atypical first language acquisition in English, Lithuanian and Polish have shown significant differences between the acquisition of morphonotactic and phonotactic consonant clusters: Morphonotactic clusters are acquired earlier and faster by typically developing children, but are more problematic for children with Specific Language Impairment. However, results on acquisition are less clear for German. The focus of this contribution is whether and how German-speaking adults differentiate between morphonotactic and phonotactic consonant clusters and vowel-consonant sequences in visual word recognition. It investigates whether sub-lexical letter sequences are found faster when the target sequence is separated from the word stem by a morphological boundary than when it is a part of a morphological root. An additional factor that is addressed concerns the position of the target cluster in the word. Due to the bathtub effect, sequences in peripheral positions in a word are more salient and thus facilitate processing more than word-internal positions. Moreover, for adults the primacy effect most favors word-initial position (whereas for young children the recency effect most favors word- final position). Our study discusses effects of phonotactic vs. morphonotactic cluster status and of position within the word.

Empathy and Emotion Processing in Mild Head Injury and Sub-clinical Psychopathy

The current study sought to investigate the nature of empathic responding and emotion processing in persons who have experienced Mild Head Injury (MHI) and how this relationship between empathetic responding and head injury status may differ in those with higher psychopathic characteristics (i.e., subclinical psychopathy). One-hundred university students (36% reporting having a previous MHI) completed an Emotional Processing Task (EPT) using images of neutral and negative valence (IAPS, 2008) designed to evoke empathy; physiological responses were recorded. Additionally, participants completed measures of cognitive competence and various individual differences (empathy - QCAE; Reniers, 2011; Psychopathy - SRP-III, Williams, Paulhus & Hare, 2007) and demographics questionnaires. MHI was found to be associated with lower affective empathy and physiological reactivity (pulse rate) while viewing images irrespective of valence, reflecting a pattern of generalized underarousal. The empathic deficits observed correlated with the individual’s severity of injury such that the greater number of injury characteristics and symptoms endorsed by a subject, the more dampened the affective and cognitive empathy reactions to stimuli and the lower his/her physiological reactivity. Importantly, psychopathy interacted with head injury status such that the effects of psychopathy were significant only for individuals indicating a MHI. This group, i.e., MHI subjects who scored higher on psychopathy, displayed the greatest compromise in empathic responding. Interestingly, the Callous Affect component of psychopathy was found to account for the empathic and emotion processing deficits observed for individuals who report a MHI; in contrast, the Interpersonal Manipulation component emerged as a better predictor of empathic and emotion deficits observed in the No MHI group. These different patterns may indicate the involvement of different underlying processes in the manifestation of empathic deficits associated with head injury or subclinical psychopathy. It also highlights the importance of assessing for prior head injury in populations with higher psychopathic characteristics due to the possible combined/enhanced influences. The results of this study have important social implications for persons who have experienced a concussion or limited neural trauma since even subtle injury to the head may be sufficient to produce dampened emotion processing, thereby impacting one’s social interactions and engagement (i.e., at risk for social isolation or altered interpersonal success). Individuals who experience MHI in conjunction with certain personality profiles (e.g., higher psychopathic characteristics) may be particularly at risk for being less capable of empathic compassion and socially-acceptable pragmatics and, as a result, may not be responsive to another person’s emotional well-being.