Research in hyperactivity has been primarily concerned with demon-strating casual relationships with cerebral dysfunction of the effects of drugs on improving learning performance. Studies which have attempted to focus on other factors influencing learning performance have demonstrated IQ and perceptual motor differences between hyperactive and normal children. More recently Koegel and Covert have shown that, among a group of autistic children, over-selectivity of components from stimulus complex may adversely influence learning performance on a simultaneous discrimination task. There have been no demonstrations of this phenomena with hyperactive children. The present study employed a simultaneous discrimination task composed of two stimulus complexes. Each complex in turn consisted of three geometric forms. Children were randomly selected, rated for activity level and then trained to respond reliably to specific complex. Once the discrimination to one of the complexes was established, the child was exposed to random pairs of components (one from the SD complex and one from the SΔ complex). Responses to either SD or SΔ were recorded. A significant relationship was found between over-selectivity for one or more SD components as a function of increasing activity level. Response errors were found to be related to selectivity but not to activity level. It would appear that performance deficits in learning a discrimination task may be, in part, related to over-selective focusing which results in failure to learn and hence, to integrate the entire stimulus complex.

Levels of participation in physical activity and sport by the New Zealand population are in decline, whilst the levels of sedentary behaviours are rising. Developing positive physical activity experiences, perceptions and habits in childhood may provide an effective approach to decrease the burden of inactivity. The purpose of this thesis was to improve knowledge of the efficacy of a sport-based intervention to increase physical activity levels of New Zealand children from a low socio-economic background. This was achieved by implementing an after-school soccer intervention at two low decile schools in Auckland, New Zealand. To determine current levels of physical activity, fifty-eight children wore a NL-2000 pedometer for four consecutive days (three weekdays and one weekend). Mean step counts (± SD) for boys were 17018 (± 4640) and for girls 12415 (± 4329) on weekdays, and for boys 12507 (± 4338) and girls 9537 (± 4421) on weekends. Nearly 50% of girls and 37% of boys were not reaching previously published daily step count recommendations of 15,000 for boys and 12,000 for girls during weekdays. The feasibility and efficacy of a six-week after-school soccer programme (2/hr.wk-1) on physical activity levels of 70 children (43 boys, 27 girls) compared to a control group of 25 children (23 boys, 2 girls) was determined in a randomised controlled trial. Measures of physical activity (4 day sealed pedometry), mass and height were completed at baseline, Week 6 (end of the intervention), and at three-month post-intervention. Compared to control, participants in the soccer programme attained higher weekday step counts after 6 weeks (treatment 16980 ± 4515; control 15021 ± 3783) and these were sustained three months post-intervention (treatment 16218 ± 4591; control 14591 ± 3488). However, these step count differences were not statistically significant. When children were grouped into activity tertiles (low, moderate and highly active) the intervention effect was more evident in the low to moderately active children. Further analysis revealed that the treatment groups’ moderate activity tertile was significantly more active than the control at follow up (p = 0.0399). This programme may offer a viable alternative to traditional physical activity interventions which concentrate on other forms of physical activity accumulation such as active transport and physical education. However, additional research needs to be carried out to determine whether the absence of statistical differences is simply a lack of statistical power.

Spatial and temporal characteristics of dust storm activity in Saudi Arabia has been established using coarse-particle (PM10) dust concentrations recorded by the KACST monitoring network during the 2000-2003 period, backward trajectory analysis and satellite imagery. Thirty three major dust episodes impacted Riyadh city during the 2000-2003 period. The majority of these intense dust episodes are experienced during the March-August period with interannual and monthly variability in both intensity and frequency. Using TOMS images in conjunction with the backward trajectories corresponding to these 33 major episodes, the dust source regions have been identified. The most vulnerable dust source areas within these identified source regions have also been determined by compiling satellite images of dusty days from the true color SeaWiFs and high resolution MODIS archives over a six-year period (2000-2005). In total 45 dust-source areas have been identified in 9 local source regions and 4 external ones. Furthermore, 38 episodes of high fine-particle (PM2.5) and PM10 dust concentrations were observed at Riyadh city and 16 and 6 episodes of elevated PM10 dust concentrations were observed at Dammam and Jeddah cities, respectively, during March-September 2006, corresponding to the dust season in Saudi Arabia. During these episodes, Riyadh city was significantly impacted by dust from the southern Iraqi source areas and the eastern source areas located to the north and to the northeast of the city, respectively. Moreover, Dammam city was also significantly impacted by dust from the southern Iraqi source areas whereas Jeddah city was evenly impacted by dust from northeastern-northwestern sources to the city, with somewhat higher PM10 concentrations from African dust source areas, located to the northwest of the city. Analysis of meteorological maps of surface pressure as well as upper air data associated with high airborne dust concentrations in Saudi Arabia was successfully performed. This analysis revealed seven common types of dust storms, triggered by a clear seasonal distribution of meteorological conditions: (1) frontal, (2) Haboob, (3) jets convergence, (4) jet streak, (5) Shamal, (6) cyclonic, and (7) gap. The majority of dust episodes that impacted Riyadh city during the study period were triggered by Haboob (~ 42 %) and Shamal (~ 37 %). Additional analyses, including elemental, ionic and biological analyses as well as model analyses were used to further characterize the airborne dust in Saudi Arabia.

The n-butanol extract of aerial parts of Cordyline australis demonstrated antifungal activity. n-Butanol and chloroform extracts of dried or fresh leaves of C. australis afforded a steroidal glycoside, which was identified as 5α-spirost-25(27)-en-3β-ol 3-O{O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside}, saponin 1. This spirostanol glycoside showed strong antifungal activity towards Trichophyton mentagrophytes and some aspecific activity and cytotoxicity against MRC5 cell. The chloroform extract of fresh leaves of C. australis yielded a second new spirostanol glycoside which was identified as 5α-spirost-25(27)-ene-1β,3β-diol 1-{O-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside}, saponin 2. The n-butanol extracts of senescent leaves of C. australis afforded a third new spirostanol glycoside that was identified as 5α-spirost-25(27)-ene-1β,3β-diol 1-{O-β-D- fucopyranoside, saponin 3. A mixture of two isomeric flavonoid glycosides was isolated from dried leaves of C. australis and shown to be a ca 1:1 mixture of isorhamnetin-3-O-{O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside}, 4 and isorhamnetin-3-O-{O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside}, 5. Three other known steroidal glycosides, β-sitosterol glucoside, 6, prosapogenin A of dioscin, 7, and trillin, 8 were also isolated from the leaves of C. australis. The n-butanol extract of dried stems of C. australis afforded (25S)-5α-spirostane-1β,3α-diol 1-{O-β-D-glucopyranoside}, 9. This spirostanol glycoside showed moderate cytotoxicity against Herpes simplex type I virus (ATCC VR733) and Polio Virus Type I (Pfiser vaccine strain).

This research investigated the mechanism of action in bacteria of 3,4-methylenedioxy-β-nitropropene (BDM-I), a very broad spectrum antimicrobial lead compound in development as an anti-infective drug. The thesis proposes that BDM-I inhibits bacterial protein tyrosine phosphatases, a novel mechanism of action for an antimicrobial agent and a new target in microorganisms. This very open investigation was directed by considerable biological information on the effects of BDM-I in microorganisms and animals which provided insights into possible and improbable cellular targets. The biological effects of BDM-I were investigated using biochemical and cell-based assays, transmission electron microscopy and whole genome DNA microarray analysis. The specific experiments and order of execution were largely dependent on information gained as the project progressed. BDM-I was shown not to target the metabolic pathways of the major classes of antibacterial drugs, which supports a novel mechanism of action. Investigation of several species-specific effects suggested that cell signalling pathways were a possible target. Based on the structure of BDM-I and review of the scientific literature on cell signalling in bacteria, the hypothesis that BDM-I acted by inhibition of protein tyrosine phosphatases (PTP) was supported by demonstrating inhibition of human and bacterial PTP's in an enzyme assay. This mechanism was consistent with other demonstrated effects: inhibition of the intracellular pathogen, Chlamydia trachomatis; inhibition of swarming in Proteus spp. and inhibition of pigment production in Serratia marcescens; and with kill kinetics in bacteria and yeast. A pilot global genome analysis of BDM-I treated Bacillus subtilis did not detect differential expression of PTP genes but has provided many avenues for further investigation. This research further supports the development of BDM-I as a broad spectrum anti-infective drug.

Improving physical activity (PA) participation is a public health priority in developed and developing countries to curb the substantial and growing prevalence of lifestyle-related diseases. Early childhood may be an especially important time to encourage PA; however, there is a paucity of research in this area. The aim of this research was to contribute to the limited body of work in PA in early childhood by investigating PA measurement approaches in young children and applying this knowledge to determine socio-environmental associations of preschool PA. An initial literature review provided the background for the thesis and determined the approaches taken in the ensuing chapters. A second literature review provided a detailed critique of research specific to PA measurement in early childhood to further inform the empirical studies. Information for the empirical chapters was drawn from three research projects: two studies were completed that assessed tools for objectively measuring PA in young children (pedometers and accelerometers), and these studies informed a final project to quantify associates of PA in a sample of preschool-aged children. Novel and important findings from the preliminary studies were that pedometer accuracy for measuring free-living PA and walking in children aged 3-5 years was poor, especially for pedometers worn at the back of the child, or during slow walking. Furthermore, when investigating the utility of accelerometers (more complex and frequently adopted tools) to quantify PA intensity in preschoolers, their application and use of commonly employed thresholds resulted in systematic underestimation of PA intensity and poor agreement (=0.09) when compared with a direct observation criterion measure. Application of existing accelerometer thresholds to classify PA intensity in preschoolers was therefore likely to yield biased estimates. Given the dearth of robust alternatives, a novel approach was developed to calculate individual activity rates from the raw accelerometer data. To account for over-dispersion in accelerometer counts, daily average activity rates per second were derived for each participant using negative binomial generalised estimating equation (GEE) models with a first-order autoregressive (AR1) correlation structure. These rates were assumed to be exchangeable between days and normally distributed. Potential socio-environmental associates of children’s activity rates and body size were thus assessed using normal GEE models with exchangeable correlation structures. Parental PA and child age were independently and significantly associated with child activity rates (P≤0.04). No relationships between child body size and PA or television (TV) exposure were found. Common approaches to PA measurement and data consideration were challenged in this research and novel robust methods devised utilising contemporary statistical methods. Accelerometer data can be successfully reduced to individual activity rates to mitigate current issues related to objective PA quantification with preschoolers. Parental involvement in preschool PA interventions is worthy of further investigation, and younger children may stand to benefit more from increased activity. Further exploration of the complex interactions between PA, exposure to media, and health outcomes in preschool-aged children is warranted.

Environments that support physical activity (PA) engagement are now seen as an important part of the solution for accumulating daily physical activity which confers health benefits, particularly transport-related PA (TPA). Despite this recognition, understanding the determinants of health-related PA has traditionally focused on identifying associations between the social environment and non-specific PA domains. As such, prior to commencing this thesis little was known about the relationships between the built environment and overall PA engagement within the New Zealand context. Little was also known about associations between TPA attitudes and behaviours, and urban design. This research sought to overcome this paucity of knowledge by investigating associations between overall PA and TPA engagement and perceptions, health outcomes, urban design, and socio-demographic variables from a public health perspective. The body of research was initiated with two literature reviews that formed the context for the following six empirical chapters. Data in the empirical chapters were drawn from three self-report surveys using adult samples. The research commenced by examining associations between urban design and overall PA engagement, and then narrowed towards TPA-specific relationships. TPA relationships were identified through the development and implementation of a reliable survey that captured associated behaviours and attitudes. Several new findings were drawn from this body of work. Overall, 21% of adults recognised they could replace automobile journeys on at least two days per week, and walking was deemed an acceptable travel alternative. Adult TPA engagement levels were low; 7% commuted to place of work/study and 32% travelled to the convenience shop by TPA modes. Furthermore, when compared with those who commuted to an occupation by TPA, respondents who used motorised travel were less likely to be classified as active (odds ratio (OR)=0.5) and be of normal body mass index (OR=0.5). No significant health relationships existed for convenience shop travel. As well, 4% of adults reported no automobile availability. When this group was compared with those with unrestricted automobile availability, they were less likely to be classified as active (OR=0.3), but were more likely to engage in TPA modes to access destinations (occupation, OR=6.3; convenience shop, OR=9.8). Occupation-related commute distances also revealed interesting findings. Overall, 50% of respondents perceived they could, and 10% of the sample actually did, commute by TPA modes for distances less than five kilometres, and relationships were strongly mediated by distance. Other urban design variables were objectively assessed with TPA engagement for occupation-related commute distances less than five kilometres. Those who travelled along the most connected street networks were more likely to engage in TPA modes (OR=6.9) when compared with respondents travelling along the least connected networks. No relationships were found with other urban design variables and TPA engagement.This research substantially contributes to this research area by identifying associations between overall PA and TPA engagement and perceptions with urban design. It is likely that shifting the perceptions of adults who recognise they can employ TPA modes, into actual TPA engagement will result in promising population health gains. Future PA initiatives with adults should consider promoting walking for transport as a sustainable solution. A lack of TPA interventions is evident; however, methodological issues need to be resolved before developing such initiatives. Although strategies aimed towards changing perceptions may be valuable for future TPA interventions, it is likely macro-scale urban design modifications (e.g., improved job-housing balance, highly-grained street networks) and legislation (e.g., automobile restrictions) will have the greatest success for increasing TPA engagement in the adult population.

Neck manipulation is commonly used in the management of some musculoskeletal disorders to reduce pain and improve movement. There is, however, little understanding about the underlying mechanism. Recent research has alluded to a neurophysiological mechanism mediated through supraspinal pathways in the central nervous system, that may alter motor activity. The purpose of this study was to determine the effect of neck manipulation on the excitability of cortical motoneurons by means of activating corticospinal pathways to the flexor carpi radialis (FCR) muscle in an active motor system using the transcranial magnetic stimulation (TMS) technique.Motor evoked potentials (MEPs) were elicited by TMS and recorded in 20 normal subjects using established procedures. The peak-to-peak amplitude of MEPs were measured both before and after C6/7 manipulation and before and after neck positioning. Both interventions were applied to the normal subjects in random order on two different days. MEPs were recorded immediately after the intervention, then seven minutes and 14 minutes later to assess the time course of the effect. Five neck pain subjects participated in the manipulation experiments. The effects of manipulation, resulting in joint cavitation, were also explored. Two trials were undertaken before the intervention and these served as control measures. MEP data was represented in two ways. Firstly, 40 MEPs were averaged over 120 seconds; secondly, 15 MEPs were average over 60 seconds. A percentage change calculation was used to express the data relative to the baseline. Alterations in cortical excitability before and after manipulation were analysed by repeated measure analysis of variance (ANOVA) on the MEP data, and percentage change scores.Cortical neurons projecting to FCR were significantly facilitated up to 60 seconds after the manipulation of the non-painful segment, relative to baseline values and the positioning control. A small but significant latent increase in excitability was also observed 15 minutes after manipulation. The response to manipulation of the painful cervical segment was significantly different from that of the non-painful segment. When manipulation of the painful segment did not result in joint cavitation, an inhibitory effect was observed. In contrast, however, cortical motoneurons were facilitated when joint cavitation was associated with manipulation.In conclusion, motor activity is enhanced with neck manipulation when cortical motoneuron excitability is measured by TMS in human subjects performing a voluntary contraction. This may explain the clinically observed improvement in spinal motion and motor control with spinal manipulation. Further, joint cavitation may be important in signifying the success of the joint manipulation. The excitatory effect on cortical motoneurons is probably mediated through a transcortical pathway by means of the activation of muscle afferents with the manipulative thrust.These findings assist in understanding the neurophysiological mechanism underlying the effect of spinal manipulation.

Ground deformation due to volcanic magma intrusion is recognised as an important precursor of eruptive activity at a volcano. The Global Positioning System (GPS) is ideally suited for this application by being able to measure three-dimensional coordinate changes of the monitoring points over time. Due to the highly disturbed ionosphere in equatorial regions, particularly during times of maximum solar activity, a deformation monitoring network consisting entirely of single-frequency GPS receivers cannot deliver baseline solutions at the desired accuracy level. In this thesis, a mixed-mode GPS network approach is proposed in order to optimise the existing continuous single-frequency deformation monitoring system on the Papandayan volcano in West Java, Indonesia. A sparse network of dual-frequency GPS receivers surrounding the deformation zone is used to generate empirical 'correction terms' in order to model the regional ionosphere. These corrections are then applied to the single-frequency data of the inner network to improve the accuracy of the results by modelling the residual atmospheric biases that would otherwise be neglected. This thesis reviews the characteristics of existing continuously operating GPS deformation monitoring networks. The UNSW-designed mixed-mode GPS-based volcano deformation monitoring system and the adopted data processing strategy are described, and details of the system's deployment in an inhospitable volcanic environment are given. A method to optimise the number of observations for deformation monitoring networks where the deforming body itself blocks out part of the sky, and thereby significantly reduces the number of GPS satellites being tracked, is presented. The ionosphere and its effects on GPS signals, with special consideration for the situation in equatorial regions, are characterised. The nature of the empirically-derived 'correction terms' is investigated by using several data sets collected over different baseline lengths, at various geographical locations, and under different ionospheric conditions. Data from a range of GPS networks of various sizes, located at different geomagnetic latitudes, including data collected on Gunung Papandayan, were processed to test the feasibility of the proposed mixed-mode deformation monitoring network approach. It was found that GPS baseline results can be improved by up to 50% in the midlatitude region when the 'correction terms' are applied, although the performance of the system degrades in close proximity to the geomagnetic equator during a solar maximum.

[Truncated abstract] The Dogs and Physical Activity (DAPA) study sought to examine the relationship between dog ownership and physical activity, in particular walking. It used an ecological model to examine the socio-demographic, intrapersonal, social environmental, physical environmental and policy-related factors affecting dog owners walking with their dog. Results from this study are presented as a series of papers four which are published, in press or accepted for publication. A review of the dog ownership, health and physical activity literature and results from qualitative research of the potential barriers and motivators to dog owners being physically active with their dogs were used to develop and test an instrument for measuring dog walking behaviour. The DAPA tool was designed to measure the amount of physical activity people undertake with their dog and dog-specific individual and environmental factors affecting people walking with their dog. It was developed as a supplementary tool for the second RESIDential Environments (RESIDE) survey. RESIDE is a 5-year longitudinal study of the physical activity levels of people building homes in new housing estates in Western Australia. Findings from the baseline survey of 1813 RESIDE participants (44% dog owners) showed that dog owners were 60% more likely than non-owners to achieve sufficient physical activity and sufficient walking and almost 80% more likely than non-owners to achieve sufficient walking for recreation in the neighbourhood after controlling for demographic, intrapersonal and environmental differences. ... Findings from the DAPA study highlight the importance of the local policy and physical environment in encouraging dog walking behaviour. Perceived lack of accessible public open space (POS) and dogspecific exercise areas were identified by focus group participants as major barriers to dog owners walking with their dog. Objective measurement of the local physical environment of dog owners supported their concerns; no dog owners in this study had access to a sign-posted off-leash park [greater than or equal to] 2 acres within their neighbourhood. Furthermore, access to local POS with dog-supportive infrastructure was associated with being a regular dog walker. Overall, the results of this study draw attention to the needs of dog owners in the allocation and design of POS. The prospective component of the DAPA study enabled examination of the causal relationship between dog ownership and physical activity. After adjusting for baseline variables, dog acquisition significantly increased minutes of recreational walking within the neighbourhood by 37 minutes. However, after further adjustment for changes in baseline variables, the increase in minutes of recreational walking within the neighbourhood from dog acquisition reduced to 21 minutes and was no longer statistically significant. Increase in intention to walk appeared to mediate the relationship between dog acquisition and increased recreational walking. This study highlights a number of important physical activity benefits associated with dog ownership and provides evidence to suggest that dog walking has the potential to positively affect the proportion of the community who are sufficiently active.