Chris Brien

Three-dimensional analysis of active cervical motion: the effect of age and gender

OBJECTIVE: To describe the effects of age and gender on three-dimensional (3D) active cervical spine motion. DESIGN: This was a descriptive study. BACKGROUND: This study expanded on previous investigations of age and gender effects on single plane motion of the cervical spine. METHODS: Sixty female and 60 male asymptomatic, normal volunteers, aged between 20 and 59 years, were examined in a standardized seated position. The 3 SPACE Isotrak system was used to measure simultaneous 3D motion of the cervical spine. RESULTS: The mean range of all the primary movements decreased significantly with age. For flexion/extension the greatest decrease occurred between the 20- and 30-year-olds, whereas for both lateral flexion and rotation, significant differences were demonstrated in subjects aged two decades apart. The coupling of motion associated with rotation was significantly related to age. CONCLUSION: Age had a significant effect on all of the primary movements. Age had less effect on the range of the coupled movements, in that the only movements to be affected were lateral flexion and extension occurring during cervical rotation. Gender had no marked effect on the primary or the coupled movements. RELEVANCE: This study provides normative data for the effects of age and gender on three-dimensional analysis of active cervical spine motion, which can be used for comparison with specific patient populations. The high level of intra-subject test-retest reliability renders the3 SPACE system of value for clinical measurement of movement pre- and post-treatment intervention for cervical spine disorders.

Integrating Image-Based Phenomics and Association Analysis to Dissect the Genetic Architecture of Temporal Salinity Responses in Rice

The genetic basis of dynamic salinity stress responses is elucidated using image-based phenomics and functional association analysis. Salinity affects a significant portion of arable land and is particularly detrimental for irrigated agriculture, which provides one-third of the global food supply. Rice (Oryza sativa), the most important food crop, is salt sensitive. The genetic resources for salt tolerance in rice germplasm exist but are underutilized due to the difficulty in capturing the dynamic nature of physiological responses to salt stress. The genetic basis of these physiological responses is predicted to be polygenic. In an effort to address this challenge, we generated temporal imaging data from 378 diverse rice genotypes across 14 d of 90 mm NaCl stress and developed a statistical model to assess the genetic architecture of dynamic salinity-induced growth responses in rice germplasm. A genomic region on chromosome 3 was strongly associated with the early growth response and was captured using visible range imaging. Fluorescence imaging identified four genomic regions linked to salinity-induced fluorescence responses. A region on chromosome 1 regulates both the fluorescence shift indicative of the longer term ionic stress and the early growth rate decline during salinity stress. We present, to our knowledge, a new approach to capture the dynamic plant responses to its environment and elucidate the genetic basis of these responses using a longitudinal genome-wide association model.

Examining the dimensions of a lifestyle tourism destination

Purpose – To develop and test a measurement model for the combined study of involvement and place attachment in a tourism context.Design/methodology/approach – The study was conducted in South Australia, a state that has positioned itself as a lifestyle tourism destination. Tourism involvement was conceptualised as a multidimensional construct consisting of centrality to lifestyle, attraction, self‐expression, and food and wine. Place attachment was also conceptualised as a multidimensional construct consisting of place identity and place dependence. Exploratory and confirmatory factor analyses were used to develop and test a measurement model using survey data from tourists in South Australia.Findings – A six factor measurement model was developed and found to have a reasonable fit with the data.Research limitations/implications – The present study findings suggest that a viable theoretical, practical, and methodological basis can be established to measure the relationships among the involvement and plac...

Salinity tolerance loci revealed in rice using high-throughput non-invasive phenotyping

High-throughput phenotyping produces multiple measurements over time, which require new methods of analyses that are flexible in their quantification of plant growth and transpiration, yet are computationally economic. Here we develop such analyses and apply this to a rice population genotyped with a 700k SNP high-density array. Two rice diversity panels, indica and aus, containing a total of 553 genotypes, are phenotyped in waterlogged conditions. Using cubic smoothing splines to estimate plant growth and transpiration, we identify four time intervals that characterize the early responses of rice to salinity. Relative growth rate, transpiration rate and transpiration use efficiency (TUE) are analysed using a new association model that takes into account the interaction between treatment (control and salt) and genetic marker. This model allows the identification of previously undetected loci affecting TUE on chromosome 11, providing insights into the early responses of rice to salinity, in particular into the effects of salinity on plant growth and transpiration.

ToF-SIMS as a new method to determine the contact angle of mineral surfaces.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used as a technique to correlate the surface chemistry of chalcopyrite particles with their contact angle. Three particle sizes (20-38, 75-105, and 150-210 microm) were used, covering a range of contact angles between 20 and 90 degrees. Multivariate statistical techniques were applied to the ToF-SIMS data in order to identify structure in the data and the surface species contributing the most to surface chemistry and hence the hydrophobicity variation. A method to calculate the contact angle of chalcopyrite by ToF-SIMS surface analysis has been developed using only information from three secondary ions: oxygen, sulfur, and a thiol collector fragment. This approach is capable of determining the surface chemistry contribution to the contact angle of individual mineral particles and the distribution of contact angles within a large ensemble of particles. Further measurements verified that the methodology can also be applied to flat surfaces, enabling rapid surface chemistry-hydrophobicity correlations to be made on a wide range of mineral and material systems.

Accounting for variation in designing greenhouse experiments with special reference to greenhouses containing plants on conveyor systems

BackgroundThere are a number of unresolved issues in the design of experiments in greenhouses. They include whether statistical designs should be used and, if so, which designs should be used. Also, are there thigmomorphogenic or other effects arising from the movement of plants on conveyor belts within a greenhouse? A two-phase, single-line wheat experiment involving four tactics was conducted in a conventional greenhouse and a fully-automated phenotyping greenhouse (Smarthouse) to investigate these issues.Results and discussionAnalyses of our experiment show that there was a small east–west trend in total area of the plants in the Smarthouse. Analyses of the data from three multiline experiments reveal a large north–south trend. In the single-line experiment, there was no evidence of differences between trios of lanes, nor of movement effects. Swapping plant positions during the trial was found to decrease the east–west trend, but at the cost of increased error variance. The movement of plants in a north–south direction, through a shaded area for an equal amount of time, nullified the north–south trend. An investigation of alternative experimental designs for equally-replicated experiments revealed that generally designs with smaller blocks performed best, but that (nearly) trend-free designs can be effective when blocks are larger.ConclusionsTo account for variation in microclimate in a greenhouse, using statistical design and analysis is better than rearranging the position of plants during the experiment. For the relocation of plants to be successful requires that plants spend an equal amount of time in each microclimate, preferably during comparable growth stages. Even then, there is no evidence that this will be any more precise than statistical design and analysis of the experiment, and the risk is that it will not be successful at all. As for statistical design and analysis, it is best to use either (i) smaller blocks, (ii) (nearly) trend-free arrangement of treatments with a linear trend term included in the analysis, or, as a last resort, (iii) blocks of several complete rows with trend terms in the analysis. Also, we recommend that the greenhouse arrangement parallel that in the Smarthouse, but with randomization where appropriate.

Differential expression of microRNAs and potential targets under drought stress in barley

Drought is a crucial environmental constraint limiting crop production in many parts of the world. microRNA (miRNA) based gene regulation has been shown to act in several pathways, including crop response to drought stress. Sequence based profiling and computational analysis have revealed hundreds of miRNAs and their potential targets in different plant species under various stress conditions, but few have been biologically verified. In this study, 11 candidate miRNAs were tested for their expression profiles in barley. Differences in accumulation of only four miRNAs (Ath-miR169b, Osa-miR1432, Hv-miRx5 and Hv-miR166b/c) were observed between drought-treated and well-watered barley in four genotypes. miRNA targets were predicted using degradome analysis of two, different genotypes, and genotype-specific target cleavage was observed. Inverse correlation of mature miRNA accumulation with miRNA target transcripts was also genotype dependent under drought treatment. Drought-responsive miRNAs accumulated predominantly in mesophyll tissues. Our results demonstrate genotype-specific miRNA regulation under drought stress and evidence for their role in mediating expression of target genes for abiotic stress response in barley.

Evaluating implicit judgments from image search clickthrough data

The interactions of users with search engines can be seen as implicit relevance feedback by the user on the results offered to them. In particular, the selection of results by users can be interpreted as a confirmation of the relevance of those results, and used to reorder or prioritize subsequent search results. This collection of search/result pairings is called clickthrough data, and many uses for it have been proposed. However, the reliability of clickthrough data has been challenged and it has been suggested that clickthrough data are not a completely accurate measure of relevance between search term and results. This paper reports on an experiment evaluating the reliability of clickthrough data as a measure of the mutual relevance of search term and result. The experiment comprised a user study involving over 67 participants and determines the reliability of image search clickthrough data, using factors identified in previous similar studies. A major difference in this work to previous work is that the source of clickthrough data comes from image searches, rather than the traditional text page searches. Image search clickthrough data were rarely examined in prior works but has differences that impact the accuracy of clickthrough data. These differences include a more complete representation of the results in image search, allowing users to scrutinize the results more closely before selecting them, as well as presenting the results in a less obviously ordered way. The experiment reported here demonstrates that image clickthrough data can be more reliable as a relevance feedback measure than has been the case with traditional text-based search. There is also evidence that the precision of the search system influences the accuracy of click data when users make searches in an information-seeking capacity.

Developing resilient green roofs in a dry climate.

Living roofs are an emerging green infrastructure technology that can potentially be used to ameliorate both climate change and urban heat island effects. There is not much information regarding the design of green roofs for dry climates and so the aim of this study was to develop low maintenance and unfertilized green roofs for a dry climate. This paper describes the effects of four important elements of green roofs namely slope, depth, growing media and plant species and their possible interactions in terms of plant growth responses in a dry climate. Sixteen medium-scale green roofs were set up and monitored during a one year period. This experiment consisted of twelve vegetated platforms and four non-vegetated platforms as controls. The design for the experiment was a split-split-plot design in which the factors Slope (1° and 25°) and Depth (100mm, 300 mm) were randomized to the platforms (main plots). Root depth and volume, average height of plants, final dry biomass and ground cover, relative growth rate, final dry shoot-root ratio, water use efficiency and leaf succulence were studied during a twelve month period. The results showed little growth of the plants in media type A, whilst the growth was significant in both media types B and C. On average, a 90% survival rate of plants was observed. Also the growth indices indicated that some plants can grow efficiently in the harsh environment created by green roofs in a dry climate. The root growth pattern showed that retained water in the drainage layer is an alternative source of water for plants. It was also shown that stormwater can be used as a source of irrigation water for green roofs during six months of the year at the study site. In summary, mild sloping intensive systems containing media type C and planted with either Chrysocephalum apiculatum or Disphyma crassifolium showed the best performance.

Effects of various isoresistive training programmes on trunk muscle performance

Isoresistive movements provide a functional method of testing muscle performance and of providing exercise; the resistance applied is usually a percentage of the maximal isometric torque which can be developed by individual subjects. The aim of the current study was to compare the effectiveness of dynamic isoresistive exercise programmes using 25, 50 or 75% of the maximum isometric flexion torque and static isometric exercises for improving the performance of the trunk flexors and extensors. Subjects comprised 42 asymptomatic females aged 18-25 years who were randomly assigned to control or exercise groups. The exercise groups undertook 2 min of exercise 3 times per week. The control subjects showed significant improvement between tests indicating a strong learning effect. The study showed that the subjects who exercised at 50% of maximum flexion isometric torque achieved the greatest increases in muscle performance on most measures. maximal isometric flexion and extension torques did not significantly change in any of the groups. Flexion and extension velocity and power were the muscle performance characteristics which improved the most in response to the training programmes. RELEVANCE:--This paper attempts to determine which among several options is the most effective isoresistive protocol for conditioning trunk muscle performance, as improved strength and power of these muscles may contribute in preventing episodes of LBP.