Showing papers by "Curtin University published in 2006"
TL;DR: The first study that integrates hafnium and oxygen isotopes, all measured in situ on the same, precisely dated detrital zircon grains reveals that crust generation in part of Gondwana was limited to major pulses at 1.9 and 3.3 Gyr ago, and that the zircons crystallized during repeated reworking of crust formed at these times.
Abstract: It is thought that continental crust existed as early as 150 million years after planetary accretion, but assessing the rates and processes of subsequent crustal growth requires linking the apparently contradictory information from the igneous and sedimentary rock records. For example, the striking global peaks in juvenile igneous activity 2.7, 1.9 and 1.2 Gyr ago imply rapid crustal generation in response to the emplacement of mantle 'super-plumes', rather than by the continuous process of subduction. Yet uncertainties persist over whether these age peaks are artefacts of selective preservation, and over how to reconcile episodic crust formation with the smooth crustal evolution curves inferred from neodymium isotope variations of sedimentary rocks. Detrital zircons encapsulate a more representative record of igneous events than the exposed geology and their hafnium isotope ratios reflect the time since the source of the parental magmas separated from the mantle. These 'model' ages are only meaningful if the host magma lacked a mixed or sedimentary source component, but the latter can be diagnosed by oxygen isotopes, which are strongly fractionated by rock-hydrosphere interactions. Here we report the first study that integrates hafnium and oxygen isotopes, all measured in situ on the same, precisely dated detrital zircon grains. The data reveal that crust generation in part of Gondwana was limited to major pulses at 1.9 and 3.3 Gyr ago, and that the zircons crystallized during repeated reworking of crust formed at these times. The implication is that the mechanisms of crust formation differed from those of crustal differentiation in ancient orogenic belts.
622 citations
TL;DR: Relatively few women achieved the international recommendations for duration of full and overall breastfeeding, but improved maternity leave provisions and more flexible working conditions may help women to remain at home with their infants longer and/or to combine successfully breastfeeding with employment outside the home.
Abstract: OBJECTIVE. To report the duration of breastfeeding among a population of Australian women and to identify factors that are associated with the duration of full breastfeeding to 6 months and any breastfeeding to 12 months. METHODS. Participants were 587 women who were recruited from 2 maternity hospitals in Perth and completed a baseline questionnaire just before or shortly after discharge from the hospital. Women were followed up by telephone interview at 4, 10, 16, 22, 32, 40, and 52 weeks postpartum. Data collected included sociodemographic, biomedical, hospital-related, and psychosocial factors associated with the initiation and the duration of breastfeeding. Cox9s proportional hazards model was used to identify factors that were associated with the risk for discontinuing full breastfeeding before 6 months and any breastfeeding before 12 months. RESULTS. At 6 months of age, fewer than one half of infants were receiving any breast milk (45.9%), and only 12% were being fully breastfed. By 12 months, only 19.2% of infants were still receiving any breast milk. Breastfeeding duration was independently, positively associated with maternal infant feeding attitudes and negatively associated with breastfeeding difficulties in the first 4 weeks, maternal smoking, introduction of a pacifier, and early return to work. CONCLUSIONS. Relatively few women achieved the international recommendations for duration of full and overall breastfeeding. Women should receive anticipatory guidance while still in the hospital on how to prevent or manage common breastfeeding difficulties and should be discouraged from introducing a pacifier before 10 weeks, if at all. Improved maternity leave provisions and more flexible working conditions may help women to remain at home with their infants longer and/or to combine successfully breastfeeding with employment outside the home.
525 citations
TL;DR: In this paper, the authors report in situ U-Pb ages and Hf isotopic data on detrital zircons from Paleozoic to Late Mesozoic strata in the Xishan area near Beijing that provide important constraints on the evolution and paleogeography of the northern part of the North China Craton.
511 citations
TL;DR: In this paper, the authors compare the performance of different interpolation methods for seasonally stable soil properties (pH, electric conductivity and organic matter) that have been demonstrated to affect yield production, and conclude that many parameters would be better identified from the RMSE statistic obtained from cross-validation after an exhaustive testing.
507 citations
TL;DR: Although metasedimentary successions are widely distributed across the North China Craton, those of Palaeoproterozoic age are restricted to three orogenic belts, namely: the Trans-North China Orogen, the Khondalite Belt and the Jiao-Liao-Ji Belt as mentioned in this paper.
506 citations
TL;DR: The technical feasibility of utilisation of fly ash as a low-cost adsorbent for various adsorption processes for removal of pollutants in air and water systems has been reviewed and Investigations revealed that unburned carbon component in fly ash plays an important role in adsorptive capacity.
461 citations
TL;DR: In this paper, a suite of A-type granites and mafic microgranular enclaves from the Early Cretaceous (126 −± 2 Ma) Qianshan pluton, Liaodong Peninsula, northeast China, were investigated.
459 citations
TL;DR: In situ zircon U-Pb and Hf-isotopic data have been determined for mafic microgranular enclaves and host granitoids from the Early Cretaceous Gudaoling batholith in the Liaodong Peninsula, NE China, in order to constrain the sources and petrogenesis of granites.
Abstract: In situ zircon U–Pb and Hf-isotopic data have been determined for mafic microgranular enclaves and host granitoids from the Early Cretaceous Gudaoling batholith in the Liaodong Peninsula, NE China, in order to constrain the sources and petrogenesis of granites. The zircon U–Pb age of the enclaves (120 ± 1 Ma) is identical to that of the host monzogranite (120 ± 1 Ma), establishing that the mafic and felsic magmas were coeval. The Hf isotopic composition of the enclaves [e
Hf(t) = +4.5 to −6.2] is distinct from the host monzogranite [e
Hf(t) = −15.1 to −25.4], indicating that both depleted mantle and crustal sources contributed to their origin. The depleted mantle component was not previously revealed by geochemical and Nd and Sr isotopic studies, showing that zircon Hf isotopic data can be a powerful geochemical tracer with the potential to provide unique petrogenetic information. Some wall-rock contamination is indicated by inherited zircons with considerably older U–Pb ages and low initial Hf isotopic compositions. Hafnium isotopic variations in Early Cretaceous zircons rule-out simple crystal–liquid fractionation or restite unmixing as the major genetic link between enclaves and host rocks. Instead, mixing of mantle-derived mafic magmas with crustal-derived felsic magmas, coupled with assimilation of wall rocks, is compatible with the data.
442 citations
TL;DR: Magmatic and metamorphic zircons have been dated from ductilely deformed gabbroic dykes defining a dyke swarm and signifying crustal extension in the northern part of the Hengshan Complex of the North China Craton.
383 citations
01 Mar 2006
TL;DR: Thermodynamic calculations suggest that the adsorption of basic dyes on MCM-22 is an endothermic reaction, which is well fitted by both the Langmuir and the Freundlich models.
Abstract: MCM-22 was employed as an effective adsorbent for removal of basic dyes including methylene blue, crystal violet, and rhodamine B from aqueous solution. The adsorption kinetics and isotherms were investigated. The adsorption capacity of MCM-22 for three dyes follows an order of MB > CV approximately RB. Kinetic studies indicate that the adsorption follows the pseudo second-order kinetics and the adsorption is a two-step diffusion process with film diffusion dominating the process. The adsorption isotherm can be well fitted by both the Langmuir and the Freundlich models. Thermodynamic calculations suggest that the adsorption of basic dyes on MCM-22 is an endothermic reaction.
380 citations
TL;DR: An Australian natural zeolite was collected, characterised and employed for basic dye adsorption in aqueous solution and it was found that the regenerated zeolites by high-temperature calcination and Fenton oxidation showed similar advertisersorption capacity but lower than the fresh sample.
TL;DR: Investigation of possible incubation periods, pathogenesis, and genetic susceptibility factors in kuru patients in Papua New Guinea found that most patients with kuru were heterozygous at polymorphic codon 129, a genotype associated with extended incubation period and resistance to prion disease.
TL;DR: This article reviewed and synthesized the science and language research and practice that arose from the current literature and presentations at an international conference referred to as the first "Island Conference" and also offered their views as to how such contributions can take place.
Abstract: In this final article, we briefly review and synthesize the science and language research and practice that arose from the current literature and presentations at an international conference, referred to as the first “Island Conference”. We add to the synthesis of the articles the conference deliberations and on‐going discussions of the field and also offer our views as to how such contributions can take place. These central issues—the definition of science literacy; the models of learning, discourse, reading, and writing and their underlying pedagogical assumptions; the roles of discourse in doing, teaching, and learning science; and the demands on teacher education and professional development in the current reforms in language and science education—provide points of departure for discussion of four possible new considerations to research in this field of endeavour that could contribute to a broader and productive scholarship and deeper and enriched understanding of both teaching and learning. These con...
TL;DR: Investigating sitting postures of asymptomatic individuals and nonspecific chronic low back pain (NS-CLBP) patients (pooled and subclassified) and evaluating the importance of subclassification revealed that patients classified with an active extension pattern sat more lordotic at the symptomatic lower lumbar spine, whereas patients with a flexion patterns sat more kyphotic, when compared with healthy controls.
Abstract: Study Design. A comparative study. Objectives. To investigate sitting postures of asymptomatic individuals and nonspecific chronic low back pain (NS-CLBP) patients (pooled and subclassified) and evaluate the importance of subclassification. Summary of Background. Currently, little evidence exists to support the hypothesis that CLBP patients sit differently from pain-free controls. Although classifying NS-CLBP patients into homogeneous subgroups has been previously emphasized, no attempts have been made to consider such groupings when examining seated posture. Methods. Three angles (sacral tilt, lower lumbar, and upper lumbar) were measured during “usual” and “slumped” sitting in 33 NS-CLBP patients and 34 asymptomatic subjects using an electromagnetic measurement device. Before testing, NS-CLBP patients were subclassified by two blinded clinicians. Twenty patients were classified with a flexion motor control impairment and 13 with an active extension motor control impairment. Results. No differences were found between control and NS-CLBP (pooled) patients during usual sitting. In contrast, analyses based on subclassification revealed that patients classified with an active extension pattern sat more lordotic at the symptomatic lower lumbar spine, whereas patients with a flexion pattern sat more kyphotic, when compared with healthy controls (F 19.7; df1 2, df2 63, P 0.001). Further, NS-CLBP patients had less ability to change their posture when asked to slump from usual sitting (t 4.2, df 65; P 0.001). Conclusions. Differences in usual sitting posture were only revealed when NS-CLBP patients were subclassified. This highlights the importance of subclassifying NS-CLBP patients.
TL;DR: The types of self-perceptions that influenced self-worth were dependent on the level of motor ability of the participants and varied according to their sex and the necessity to assess specific types of motor deficit when tailoring intervention strategies for children with motor disorders, particularly within the academic setting.
TL;DR: A stereotaxic rat brain MRI template set with a co-registered digital anatomical atlas is described and its application to the analysis of a pharmacological MRI study of apomorphine is illustrated.
TL;DR: A meta-analysis of 54 published studies tested the extent to which a systematic misclassification error was committed by including as ‘abstainers’ many people who had reduced or stopped drinking, a phenomenon associated with ageing and ill health.
Abstract: The majority of prospective studies on alcohol use and mortality risk indicates that abstainers are at increased risk of mortality from both all causes and coronary heart disease (CHD). This meta-a...
TL;DR: The Xuelongbao plutonic complex in the eastern margin of the Tibetan Plateau is dated at 748-±-7-Ma using the SHRIMP zircon U-Pb method and represents part of the Neoproterozoic igneous assemblage of South China as mentioned in this paper.
TL;DR: Zircon U-Pb isotopic dating by LA-ICP-MS and SHRIMP methods indicates that the Guanghua and Ji'an Groups were formed between 2.1 and 2.0 Ga, but that the rocks of the Laoling Group may have formed in two episodes at 2.5 −2.2 and 2.9 −1.9 ε, respectively.
TL;DR: In this paper, the authors apply the electron microprobe Th-U-Pb monazite dating technique to determine the ages of the peak metamorphic event and subsequent exhumation of the low- to medium-grade Luliang and Wutai complexes in the Trans-North China Orogen.
TL;DR: The results highlight the importance of postural training specificity when the aim is to activate the lumbo-pelvic stabilizing muscles in subjects with back pain.
Abstract: Study design: A normative within-subjects single-group study.
Objective: To compare spinal-pelvic curvature and trunk muscle activation in 2 upright sitting postures ("thoracic" and "lumbo-pelvic") and slump sitting in a pain-free population.
Summary of background data: Clinical observations suggest that both upright and slump sitting postures can exacerbate low back pain. Little research has investigated the effects of different upright sitting postures on trunk muscle activation.
Methods: Spinal-pelvic curvature and surface electromyography of 6 trunk muscles were measured bilaterally in 2 upright (thoracic and lumbo-pelvic) sitting postures and slump sitting in 22 subjects.
Results: Thoracic, compared to lumbo-pelvic, upright sitting showed significantly greater thoracic extension (P < 0.001), with significantly less lumbar extension (P < 0.001) and anterior pelvic tilt (P = 0.03). Furthermore, there was significantly less superficial lumbar multifidus (P < 0.001) and internal oblique (P = 0.03) activity, with significantly higher thoracic erector spinae (P < 0.001) and external oblique (P = 0.04) activity in thoracic upright sitting. There was no significant difference in superficial lumbar multifidus activity between thoracic upright and slump sitting.
Conclusions: Different upright sitting postures resulted in altered trunk muscle activation. Thoracic when compared to lumbo-pelvic upright sitting involved less coactivation of the local spinal muscles, with greater coactivation of the global muscles. These results highlight the importance of postural training specificity when the aim is to activate the lumbo-pelvic stabilizing muscles in subjects with back pain.
TL;DR: 6MWD in this healthy population-based sample of males and females exceeds values previously reported and height and FEV(1) were identified as significant independent predictors of 6MWd in this group.
TL;DR: In this article, the authors present a review of electrochemical impedance spectroscopy (EIS) based characterization of a wide range of electroanalytical sensor systems, including potentiometric, amperometric, electrochemical biosensors.
TL;DR: Subclassifying nonspecific chronic LBP patients revealed clear differences in sEMG activity during sitting between pain-free subjects and subgroups of nonspe Specific Chronic low back pain patients.
Abstract: STUDY DESIGN A cross-sectional comparative study between healthy controls and two subgroups of nonspecific chronic low back pain (LBP) patients. OBJECTIVES To determine differences in trunk muscle activation during usual unsupported sitting. SUMMARY OF BACKGROUND DATA Patients with LBP commonly report exacerbation of pain on sitting. Little evidence exists to confirm that subgroups of patients with nonspecific chronic LBP patients use different motor patterns in sitting than pain-free controls. METHODS A total of 34 pain-free and 33 nonspecific chronic LBP subjects were recruited. Two blinded clinicians classified nonspecific chronic LBP patients into two subgroups (active extension pattern and flexion pattern). Surface electromyography (sEMG) was recorded from five trunk muscles during subjects' unsupported "usual" and "slumped" sitting. RESULTS No differences in trunk muscle activity were observed between healthy controls and nonspecific chronic LBP groups for usual sitting. When the classification system was applied, differences were identified. Compared with no-LBP controls, the active extension pattern group presented with higher levels of cocontraction of superficial fibers of lumbar multifidus (12%), iliocostalis lumborum pars thoracis (36%) and transverse fibers of internal oblique (43%). while the flexion pattern group showed a trend toward lower activation patterns (lumbar multifidus, -7%; iliocostalis lumborum pars thoracis, -6%, and transverse fibers of internal oblique, -5%). The flexion relaxation ratio of the back muscles was lower for nonspecific chronic LBP (superficial lumbar multifidus: t = 4.5; P < 0.001 and iliocostalis lumborum pars thoracis:t = 2.7; P < 0.001), suggesting a lack of flexion relaxation for the nonspecific chronic LBP. CONCLUSION Subclassifying nonspecific chronic LBP patients revealed clear differences in sEMG activity during sitting between pain-free subjects and subgroups of nonspecific chronic LBP patients.
TL;DR: A rigorous method for estimating some of the calibration parameters in airborne laser scanning (ALS), namely the three bore-sight angles and the range-finder offset, which is shown to be not only accurate but also very robust in terms of convergence.
Abstract: We present a rigorous method for estimating some of the calibration parameters in airborne laser scanning (ALS), namely the three bore-sight angles and the range-finder offset. The technique is based on expressing the system calibration parameters within the direct-georeferencing equation separately for each target point, and conditioning a group of points to lie on a common surface of a known form such as a plane. However, the assumed a priori information about q chosen planar features is only their form not the spatial orientation or position. Thus, the 4·q plane parameters are estimated together with the calibration parameters in a combined adjustment model that makes use of GPS/INS-derived position and orientation as well as LiDAR range and encoder angle as observations. To make the approach practical when working with voluminous ALS and GPS/INS data, the contribution of each laser point to the normal equations is formed sequentially. The discussions focus on practical examples with data from a continuously-rotating scanner that reveal the conditions under which almost complete de-correlation between the estimated parameters occurs. In such a case, all bore-sight angles are determined with accuracy that is several times superior to the system noise level. Given sufficiently strong geometry, the presented method is shown to be not only accurate but also very robust in terms of convergence. When appropriate, the method is applicable for calibration of additional systematic effects such as laser-beam encoder offsets or scale factor with minimal modification to the functional model.
TL;DR: A robust procedure for the determination of 16 US EPA PAHs in both aqueous and solid samples from the WWTP of Fusina (Venice, Italy) is presented.
TL;DR: It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 1.2:1 weight ratio of Na: fly-ash at 250-350 degrees C.
TL;DR: In this paper, the SHRIMP zircon U-Pb dating of the Shangtaihua group of the North China Craton has been reported, showing that the group formed during the Paleoproterozoic (between 2.26 and 2.14 Ga).
TL;DR: Preliminary results support that a relationship may exist between flexed spinal postures, reduced back muscle endurance, physical inactivity and LBP in subjects with a history of flexion injury and pain.
TL;DR: In this paper, the authors demonstrate the usefulness of the policy network approach to describe, analyze, and explain the dynamics of the tourism policy domain with its vast variety of actors and complex web of interactions.