51 resultados para 14Carbon uptake rate, attributed to calcification, fractionated

em Deakin Research Online - Australia


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The type material of Loxocythere (Loxocythere) ouyenensis (Chapman, 1914) from mid Cenozoic strata of the Mallee Bore No. 11 in the Murray Basin, S.E. Australia is partially redescribed and refigured. This species belongs to a discrete group of large elongate Cenozoic fossil and living Loxocythere species, the carapaces of which possess sub-rectangular inner margin outlines, and broadly rounded posterior extremities. Some much smaller but otherwise very similarly shaped species, that have previously been placed under the genus Microcytherura (i.e. Microcytherura? peterroyi Yassini and Jones, 1995) or the genus Hemiparvocythere Hartmann, 1982 (i.e. Hemiparvocythere Iagunicola Hartmann, 1982), are also known from marine Cenozoic strata and modern seas of the Australasian region. There is a marked difference in the shape of the inner margin between this group of small Australasian forms and European species of Microcytherura s.s .. The former have broadly rounded posterior inner margins, whilst the latter have acutely rounded posterior inner margins. The latter also usually present posterior extremities located well below mid carapace height. It is here argued that this difference in inner margin shape between smaller Australasian species such as Microcytherura? peterroyi, and European species of Microcytherura s.s ., suggests that there is not a direct phylogenetic relationship between these two species groups.

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The goal of this paper is to examine the importance of permanent and transitory shocks using a more efficient trend-cycle decomposition of the real exchange rate series. Our main contribution is that in measuring the impact of shocks, we not only impose common trend restrictions but also common cycle restrictions. We later confirm, through a post sample forecasting exercise, the efficiency gains from imposing common cycle restrictions. Our results indicate that permanent shocks are responsible for the bulk of the real exchange rate variations for Japan, Italy, Germany, France, and the UK vis-à-vis the US dollar over short horizons. For Canada, however, transitory shocks are dominant over the short horizon. In sum, while for Japan, France, and Italy, around 15% of the variation in real exchange rate is due to transitory shocks, for Canada, Germany and the UK, over 25% of the variations over the short horizon are due to transitory shocks. Thus, we claim that the role of transitory shocks should not be ignored.

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There is an augmented platelet intracellular calcium response to serotonin stimulation in major depression. The role that calcium influx has in this process is not known. The objective of this study was to determine platelet calcium influx in response to serotonin by two methods, Mn2+ influx and 45Ca2+ uptake, in order to observe if the uptake response to serotonin was augmented in major depression by comparing the response to normal controls. The use of the two methods of calcium influx showed that serotonin stimulates calcium uptake into platelets. Furthermore, patients with major depression have significantly augmented platelet calcium uptake in response to serotonin. The interesting finding was that calcium uptake into platelets is biphasic, occurring immediately and after five minutes. These results may support the two pool model for calcium oscillations within cells whereby extracellular calcium is needed for intracellular calcium release, and for replenishment of depleted stores once intracellular calcium is released.

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This research tested the hypothesis that women who had higher levels of physical fitness will have lower hypothalamo-pituitary-adrenal axis (cortisol) and sympatho-adrenal medullary system (blood pressure and heart rate) responses to food intake compared with women who had low levels of physical fitness. Lower fitness (n = 22; maximal oxygen consumption = 27.4 ± 1.0 mL∙kg(-1)·min(-1)) and higher fitness (n = 22; maximal oxygen consumption = 41.9 ± 1.6 mL∙kg(-1)·min(-1)) women (aged 30-50 years; in the follicular phase of the menstrual cycle) who participated in levels of physical activity that met (lower fitness = 2.7 ± 0.5 h/week) or considerably exceeded (higher fitness = 7.1 ± 1.4 h/week) physical activity guidelines made their own lunch using standardised ingredients at 1200 h. Concentrations of cortisol were measured in blood samples collected every 15 min from 1145-1400 h. Blood pressures and heart rate were also measured every 15 min between 1145 h and 1400 h. The meal consumed by the participants consisted of 20% protein, 61% carbohydrates, and 19% fat. There was a significant overall response to lunch in all of the parameters measured (time effect for all, p < 0.01). The cortisol response to lunch was not significantly different between the groups (time × treatment, p = 0.882). Overall, both groups showed the same pattern of cortisol secretion (treatment p = 0.839). Systolic blood pressure, diastolic blood pressure, mean arterial pressure, or heart rate responses (time × treatment, p = 0.726, 0.898, 0.713, and 0.620, respectively) were also similar between higher and lower fitness women. Results suggest that the physiological response to food intake in women is quite resistant to modification by elevated physical fitness levels.

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Background. Many researchers have explored the barriers to research uptake in order to overcome them and identify strategies to facilitate research utilization. However, the research–practice gap remains a persistent issue for the nursing profession.

Aims and objectives. The aim of this study was to gain an understanding of perceived influences on nurses' utilization of research, and explore what differences or commonalities exist between the findings of this research and those of studies that have been conducted in various countries during the past 10 years.

Design. Nurses were surveyed to elicit their opinions regarding barriers to, and facilitators of, research utilization. The instrument comprised a 29-item validated questionnaire, titled Barriers to Research Utilisation Scale (BARRIERS Scale), an eight-item scale of facilitators, provision for respondents to record additional barriers and/or facilitators and a series of demographic questions.

Method. The questionnaire was administered in 2001 to all nurses (n = 761) working at a major teaching hospital in Melbourne, Australia. A 45% response rate was achieved.

Results. Greatest barriers to research utilization reported included time constraints, lack of awareness of available research literature, insufficient authority to change practice, inadequate skills in critical appraisal and lack of support for implementation of research findings. Greatest facilitators to research utilization reported included availability of more time to review and implement research findings, availability of more relevant research and colleague support.

Conclusion. One of the most striking features of the findings of the present study is that perceptions of Australian nurses are remarkably consistent with reported perceptions of nurses in the US, UK and Northern Ireland during the past decade.

Relevance to clinical practice. If the use of research evidence in practice results in better outcomes for our patients, this behoves us, as a profession, to address issues surrounding support for implementation of research findings, authority to change practice, time constraints and ability to critically appraise research with conviction and a sense of urgency.

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Arteriovenous fistulae are considered the gold standard for haemodialysis vascular access. Their use can be fraught with complications for both the patient and cannulator, with knowledge, expertise and skills being key factors in reducing access associated morbidity. There is mounting evidence demonstrating the efficacy of the buttonhole technique. One disturbing problem noted with the buttonhole experience has been an increased rate in site infections, anecdotally attributed to poor buttonhole site preparation. Enhanced knowledge and skills for nurses are crucial in increasing patient comfort and improving outcomes.

Although knowledge and skill acquisition related to vascular access are often the focus of individual institutional educational initiatives, a national evidence based program that provides free equitable access to all nurses does not exist in Australasia. A survey of Australasian Nephrology Educators’ identified the need for more effective and consistent delivery of clinical education for nurses using innovative, web‐based approaches that support the tenets of e-learning methodologies. This paper will discuss the development and implementation of an e-learning program for buttonhole cannulation. The preparedness of participants to professionally engage with buttonhole cannulation and their self-efficacy (estimates) in undertaking learning about the clinical procedure using e-learning will be evaluated. In addition it will highlight the benefits of inter‐organizational partnerships and how they can facilitate positive change in teaching and learning practices aimed at improving patient outcomes. This project has unique characteristics that collectively provide value, distinction and innovation to patients, nurses, and renal departments across Australasia. As the e-learning program is founded on evidence based practice this project is easily transferable to an international context.

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SiOx films have several advantages as an interlayer dielectric in electronic devices owing to the strong adhesion between SiOx and the substrate. In this study, the coating performance as a function of the N2O flow rate was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests in an undisturbed environment. In addition, the coatings were examined by atomic force microscopy and Fourier transform infrared reflection spectroscopy. The SiOx films on a stainless-steel substrate showed the highest coating performance at a N2O flow rate of 120 sccm. This was attributed to the films having the lowest porosity value among those examined as a result of the fragmentation of SiO and SiO2 bonds and the improved surface roughness.

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Metal homoeostasis in cyanobacteria is based on uptake and export systems that are controlled by their own regulators. This study characterises the zinc uptake (Znu) system in Nostoc punctiforme. The system was found to comprise of three subunits in an ACB operon: a Zn2+-binding protein (ZnuA18), a transmembrane domain (ZnuB) and an ATPase (ZnuC). These proteins are encoded within the znu operon regulated by a zinc uptake transcription repressor (Zur). Interestingly, a second Zn2+-binding protein (ZnuA08) was also identified at a distal genomic location. Interactions between components of the ZnuACB system were investigated using knockouts of the individual genes. The znuA08-, znuA18-, znuB- and znuC- mutants displayed overall reduced znuACB transcript levels, suggesting that all system components are required for normal expression of znu genes. Zinc uptake assays in the Zn2+-binding protein mutant strains showed that the disruption of znuA18 had a greater negative effect on zinc uptake than disruption of znuA08. Complementation studies in Escherichia coli indicated that both znuA08 and znuA18 were able to restore zinc uptake in a znuA- mutant, with znuA18 permitting the highest zinc uptake rate. The N. punctiforme zur was also able to complement the E. coli zur- mutant.

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The slow uptake of Education for Sustainability (EfS) curricula in universities has, partly, been attributed to academics' perceptions that EfS has little relevance within some disciplines. Understanding teaching academics' attitudes, values and experiences of EfS across disciplines can inform future EfS efforts in higher education. This paper presents one part of a larger study that sought the views of ≈6% of the entire university teaching workforce of Australia. One quarter of the teaching academics in every discipline of every Australian university (except one) (n = 38) was sent an online questionnaire asking for their opinions of EfS. Precisely, 1819 academics participated (26% response rate) and data was analysed with descriptive and inferential statistics. The findings suggest that academics are supportive of EfS for all university students. Support, perceived relevance and reported difficulties with EfS are discipline specific; academics would respond positively to EfS framed within their disciplinary worldviews.

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The effect of Fe in Al is technologically important for commercial Al-alloys, and in recycled Al. This work explores the use of the novel rapid solidification technology, known as direct strip casting, to improve the recyclability of Al-alloys. We provide a comparison between the corrosion and microstructure of Al-Fe alloys prepared with wide-ranging cooling rates (0.1. °C/s to 500. °C/s). Rapid cooling was achieved via direct strip casting, while slow cooling was achieved using sand casting. Corrosion was studied via polarisation and immersion tests, followed by surface analysis using scanning electron microscopy and optical profilometry. It was shown that the corrosion resistance of Al-Fe alloys is improved with increased cooling rates, attributed to the reduced size and number of Fe-containing intermetallics.

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The high voltage LiNi0.5Mn1.5O4 cathode with a disordered spinel structure is synthesized by a glycine-assisted low-temperature reaction follows by a thermal treatment at 750 °C, 850 °C, and 950 °C for 12 h. Glycine is used as a chelating agent for the first time to build required environment for shaping the precursor of LiNi0.5Mn1.5O4 materials. The microstructure and morphology of the LiNi0.5Mn1.5O4 product are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, and transmission electron microscopy. The sample prepares at 750 °C reveals small particles with well-defined crystals as confirmed by electron microscopy. Electrochemical results demonstrate that LiNi0.5Mn1.5O4 electrode anneal at 750 °C (compare to other two samples) delivers the highest reversible capacity of 110 mAh g-1 at 0.2C after 100 cycles with good rate capability. The enhanced electrochemical performance could be attributed to the smaller particle sizes as well as well-defined crystals which provide a directional and shorter diffusion path length for Li+ transportation within the crystals.

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Trans-equatorial long-distance migrations of high-latitude breeding animals have been attributed to narrow ecological niche widths. We suggest an alternative hypothesis postulating that trans-equatorial migrations result from a possible increase in the rate at which body stores to fuel migration are deposited with absolute latitude; that is, longer, migrations away from the breeding grounds surpassing the equator may actually enhance fueling rates on the nonbreeding grounds and therewith the chance of a successful, speedy and timely migration back to the breeding grounds. To this end, we first sought to confirm the existence of a latitudinal trend in fuel deposition rate in a global data set of free-living migratory shorebirds and investigated the potential factors causing this trend. We next tested two predictions on how this trend is expected to impact the migratory itineraries on northward migration under the time-minimization hypothesis, using 56 tracks of high-latitude breeding shorebirds migrating along the East Asian-Australasian Flyway. We found a strong positive effect of latitude on fuel deposition rate, which most likely relates to latitudinal variations in primary productivity and available daily foraging time. We next confirmed the resulting predictions that (1) when flying from a stopover site toward the equator, migrants use long jumps that will take them to an equivalent or higher latitude at the opposite hemisphere; and (2) that from here onward, migrants will use small steps, basically fueling only enough to make it to the next suitable staging site. These findings may explain why migrants migrate "the extra mile" across the equator during the nonbreeding season in search of better fueling conditions, ultimately providing secure and fast return migrations to the breeding grounds in the opposite hemisphere.

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This study examined the effect of reduced plasma free fatty acid (FFA) availability on carbohydrate metabolism during exercise. Six untrained women cycled for 60 minutes at approximately 58% of maximum oxygen uptake after ingestion of a placebo (CON) or nicotinic acid (NA), 30 minutes before exercise (7.4 ± 0.5 mg·kg−1 body weight), and at 0 minutes (3.7 ± 0.3 mg·kg−1) and 30 minutes (3.7 ± 0.3 mg·kg−1) of exercise. Glucose kinetics were measured using a primed, continuous infusion of [6,6-2H] glucose. Plasma FFA (CON, 0.86 ± 0.12; NA, 0.21 ± 0.11 mmol·L−1 at 60 minutes, P < .05) and glycerol (CON, 0.34 ± 0.05; NA, 0.10 ± 0.04 mmol·L−1 at 60 minutes, P < .05) were suppressed throughout exercise. Mean respiratory exchange ratio (RER) during exercise was higher (P < .05) in NA (0.89 ± 0.02) than CON (0.83 ± 0.02). Plasma glucose and glucose production were similar between trials. Total glucose uptake during exercise was greater (P < .05) in NA (1,876 ± 161 μmol·kg−1) than in CON (1,525 ± 107 μmol·kg−1). Total fat oxidation was reduced (P < .05) by approximately 32% during exercise in NA. Total carbohydrate oxidized was approximately 42% greater (P < .05) in NA (412 ± 40 mmol) than CON (290 ± 37 mmol), of which, approximately 16% (20 ± 10 mmol) could be attributed to glucose. Plasma insulin and glucagon were similar between trials. Catecholamines were higher (P < .05) during exercise in NA. In summary, during prolonged moderate exercise in untrained women, reduced FFA availability results in a compensatory increase in carbohydrate oxidation, which appears to be due predominantly to an increase in glycogen utilization, although there was a small, but significant, increase in whole body glucose uptake.