240 resultados para Earth pressure.


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The results of pressure-tuning Raman spectroscopic, X-ray powder diffraction and solid-state 13C-NMR studies of selected dicarboxylate anions intercalated in a Mg-Al layered double hydroxide (talcite) lattice are reported. The pressure dependences of the vibrational modes are linear for pressures up to 4.6 GPa indicating that no phase transitions occur. The interlayer spacings show that the oxalate, malonate and succinate dianions are oriented perpendicular to the layers, but the glutarate and adipate are tilted. The solid-state 13C-NMR spectra of these materials show full chemical shift anisotropy and, therefore, the anions are not mobile at room temperature.

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Rare earth element geochemistry in carbonate rocks is utilized increasingly for studying both modern oceans and palaeoceanography, with additional applications for investigating water–rock interactions in groundwater and carbonate diagenesis. However, the study of rare earth element geochemistry in ancient rocks requires the preservation of their distribution patterns through subsequent diagenesis. The subjects of this study, Pleistocene scleractinian coral skeletons from Windley Key, Florida, have undergone partial to complete neomorphism from aragonite to calcite in a meteoric setting; they allow direct comparison of rare earth element distributions in original coral skeleton and in neomorphic calcite. Neomorphism occurred in a vadose setting along a thin film, with degradation of organic matter playing an initial role in controlling the morphology of the diagenetic front. As expected, minor element concentrations vary significantly between skeletal aragonite and neomorphic calcite, with Sr, Ba and U decreasing in concentration and Mn increasing in concentration in the calcite, suggesting that neomorphism took place in an open system. However, rare earth elements were largely retained during neomorphism, with precipitating cements taking up excess rare earth elements released from dissolved carbonates from higher in the karst system. Preserved rare earth element patterns in the stabilized calcite closely reflect the original rare earth element patterns of the corals and associated reef carbonates. However, minor increases in light rare earth element depletion and negative Ce anomalies may reflect shallow oxidized groundwater processes, whereas decreasing light rare earth element depletion may reflect mixing of rare earth elements from associated microbialites or contamination from insoluble residues. Regardless of these minor disturbances, the results indicate that rare earth elements, unlike many minor elements, behave very conservatively during meteoric diagenesis. As the meteoric transformation of aragonite to calcite is a near worst case scenario for survival of original marine trace element distributions, this study suggests that original rare earth element patterns may commonly be preserved in ancient limestones, thus providing support for the use of ancient marine limestones as proxies for marine rare earth element geochemistry.

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This paper contributes to the recent debate about the role of referees in the home advantage phenomenon. Specifically, it aims to provide a convincing answer to the newly posed question of the existence of individual differences among referees in terms of the home advantage (Boyko, Boyko, & Boyko, 2007; Johnston, 2008). Using multilevel modelling on a large and representative dataset we find that (1) the home advantage effect differs significantly among referees, and (2) this relationship is moderated by the size of the crowd. These new results suggest that a part of the home advantage is due to the effect of the crowd on the referees, and that some referees are more prone to be influenced by the crowd than others. This provides strong evidence to indicate that referees are a significant contributing factor to the home advantage. The implications of these findings are discussed both in terms of the relevant social psychological research, and with respect to the selection, assessment, and training of referees.

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Background: To compare the intraocular pressure readings obtained with the iCare rebound tonometer and the 7CR non-contact tonometer with those measured by Goldmann applanation tonometry in treated glaucoma patients. Design: A prospective, cross sectional study was conducted in a private tertiary glaucoma clinic. Participants: 109 (54M:55F) patients including only eyes under medical treatment for glaucoma. Methods: Measurement by Goldmann applanation tonometry, iCare rebound tonometry and 7CR non-contact tonometry. Main Outcome Measures: Intraocular pressure. Results: There were strong correlations between the intraocular pressure measurements obtained with Goldmann and both the rebound and non-contact tonometers (Spearman r values ≥ 0.79, p < 0.001). However, there were small, statistically significant differences between the average readings for each tonometer. For the rebound tonometer, the mean intraocular pressure was slightly higher compared to the Goldmann applanation tonometer in the right eyes (p = 0.02), and similar in the left eyes (p = 0.93) however these differences did not reach statistical significance. The Goldmann correlated measurements from the noncontact tonometer were lower than the average Goldmann reading for both right (p < 0.001) and left (p > 0.01) eyes. The corneal compensated measurements from the non-contact tonometer were significantly higher compared to the other tonometers (p ≤ 0.001). Conclusions: The iCare rebound tonometer and the 7CR non-contact tonometer measure IOP in fundamentally different ways to the Goldmann applanation tonometer. The resulting IOP values vary between the instruments and will need to be considered when comparing clinical versus home acquired measurements.

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Objective: Adherence to Continuous Positive Airway Pressure Therapy (CPAP) for Obstructive Sleep Apnoea (OSA) is poor. We assessed the effectiveness of a motivational interviewing intervention (MINT) in addition to best practice standard care to improve acceptance and adherence to CPAP therapy in people with a new diagnosis of OSA. Method: 106 Australian adults (69% male) with a new diagnosis of obstructive sleep apnoea and clinical recommendation for CPAP treatment were recruited from a tertiary sleep disorders centre. Participants were randomly assigned to receive either three sessions of a motivational interviewing intervention ‘MINT’ (n=53; mean age=55.4 years), or no intervention ‘Control’ (n=53; mean age=57.74). The primary outcome was the difference between the groups in objective CPAP adherence at 1 month, 2 months, 3 months and 12 months follow-up. Results: Fifty (94%) participants in the MINT group and 50 (94%) of participants in the control group met all inclusion and exclusion criteria and were included in the primary analysis. The hours of CPAP use per night in the MINT group at 3 months was 4.63 hours and 3.16 hours in the control group (p=0.005). This represents almost 50% better adherence in the MINT group relative to the control group. Patients in the MINT group were substantially more likely to accept CPAP treatment. Conclusions: MINT is a brief, manualized, effective intervention which improves CPAP acceptance and objective adherence rates as compared to standard care alone.

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Young drivers, aged 17 to 24 years, have the highest fatality rate in Australia. It is believed that part of this risk is due to pressure from peer passengers to engage in speeding; which may be active (i.e., verbal encouragement) or passive (i.e., perceived pressure on the part of the driver). The Theory of Planned Behaviour (TPB) was used to investigate this impact of peer passengers on young drivers, particularly the influence of the type of peer pressure and a driver’s level of identification with their passengers. A scenario-based questionnaire was constructed, informed by focus groups and pilot studies, and distributed to university students (N = 398). The questionnaire measured participants’ intentions and the TPB constructs, including two components of perceived behaviour control, within a baseline scenario as well as an experimental scenario in which the variables of type of pressure and identification were manipulated. Consistent with the hypotheses, the study found that attitudes and self-efficacy significantly predicted intentions over and above the variance explained by the sociodemographic variables of age, gender, self-esteem, sensation seeking, as well as past behaviour and exposure. Across the scenarios, attitudes explained between 4.3% and 14.5%, while self-efficacy to refrain from speeding explained between 4.9% and 17.1%, of the unique variance in intentions to speed. However, contrary to expectations, intentions to speed were found to be higher in the “no passenger” than “passenger present” conditions, although this finding is not completely inconsistent with recent literature. A high level of identification with passengers led to higher intentions to speed than low identification as expected, but, inconsistent with expectations, different types of pressure (i.e., active versus passive) did not influence intentions to speed.