57 resultados para field theories in dimensions other than four

em Deakin Research Online - Australia


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Background : We sought to determine whether skeletal muscle oxidative capacity, fiber type proportions, and fiber size, capillary density or muscle mass might explain the impaired exercise tolerance in chronic heart failure (CHF). Previous studies are equivocal regarding the maladaptations that occur in the skeletal muscle of patients with CHF and their role in the observed exercise intolerance.

Methods and results :
Total body O2 uptake (VO2peak) was determined in 14 CHF patients and 8 healthy sedentary similar-age controls. Muscle samples were analyzed for mitochondrial adenosine triphosphate (ATP) production rate (MAPR), oxidative and glycolytic enzyme activity, fiber size and type, and capillary density. CHF patients demonstrated a lower VO2peak (15.1±1.1 versus 28.1±2.3 mL·kg&minus;1·min&minus;1, P<.001) and capillary to fiber ratio (1.09±0.05 versus 1.40±0.04; P<.001) when compared with controls. However, there was no difference in capillary density (capillaries per square millimeter) across any of the fiber types. Measurements of MAPR and oxidative enzyme activity suggested no difference in muscle oxidative capacity between the groups.

Conclusions : Neither reductions in muscle oxidative capacity nor capillary density appear to be the cause of exercise limitation in this cohort of patients. Therefore, we hypothesize that the low VO2peak observed in CHF patients may be the result of fiber atrophy and possibly impaired activation of oxidative phosphorylation.

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The effects of high pressure on molecular arrangment in liquid crystals were observed by optical measurements on two nematogens. It was possible to deduce how volume varies as a factor of temperature and pressure and how nematic order parameter changes under the influence of high pressure.

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 While data processing methods in metabolomic studies often work with 'n' number of dimensions, analytical techniques, with the notable exception of NMR, have mostly stuck only to one. Peak overlap continues to be a problem and there is an ever-present demand to maximize the number of metabolites that can be separated and identified in a single run. One method that might help to overcome these issues is multidimensional liquid chromatography, which uses two columns of different phases. A sequential collection of aliquots is made from the first column and reinjected onto a second, and the resulting data are then plotted in 2D or 3D space. The total peak capacity of such a system is the combined peak capacities of each column. The 'offline' version of this technique, using a fraction collector, was introduced over 30 years ago but with recent advances in instrumentation and software, particularly the 'online' approach using automated switching valves, has led to increasing interest in the technique. Both offline and online methods can be carried out as a comprehensive procedure, or via 'heart-cutting', in which only specific peaks are analysed in the second dimension. Past applications include proteomics, natural product chemistry, forensic science and pharmaceutical analysis. These successes are likely to be built on in the future as new column chemistries and bio-informatic approaches are developed. In this review an overview of the theory of twodimensional liquid chromatography is presented, its potential in the field of metabolomics is assessed and predictions for future research directions are made.

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This study was designed to examine the relationship between dyadic adjustment and intimacy, and to determine how this varies for different types of relationships between males and females, and for relationships of different duration. Eighty-seven heterosexual couples (10 dating, 21 living together, 56 married) participated in the study. The results demonstrated that there was a strong interrelationship between intimacy and dyadic adjustment for both males and females. Those in relationships of longer duration and married couples experienced higher levels of intimacy and relationship satisfaction than other couples. There was a general trend for married couples and those who were living together to have a higher level of agreement on their levels of intimacy and relationship adjustment than couples who were dating. The implication of these findings for obtaining a better understanding of the lifecycle of relationships is discussed.

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The focus of this research is to identify the perceptions that professional sports club managers have about the impact that on-field success has on the attractiveness of a sport organisation to a prospective sponsor. From a series of semi-structured in-depth interviews conducted with the sponsorship/marketing managers from seven Melbourne based Australian Football League (AFL) clubs, an analysis of the importance of on-field success as a precursor for sponsorship was determined. The interview schedule consisted of four phases and concluded with a scale to rate the relative importance of on-field performance. The results indicated that AFL Club Managers believe that the onfield performance of the team does have an impact, but it is largely associated with the media coverage that this on-field success provides. They also identified that in the sport of AFL on-field success is largely controlled by the AFL governing organisation.

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Objective : To compare the prevalence of the Metabolic Syndrome (MetS) defined by four definitions and to determine which definition best identifies those at high cardiovascular disease (CVD) risk and with insulin resistance.

Methods : AusDiab is a population-based survey of 11,247 Australians. Participants had anthropometry, blood pressure, and fasting biochemistry. Ten-year CVD risk was calculated.

Results :
The prevalence of the MetS using the ATPIII, WHO, IDF, and EGIR definitions was 22.1% (95%Cl: 18.8, 25.4), 21.7% (19.0, 24.3), 30.7% (27.1, 34.3), and 13.4% (11.8, 14.9), respectively. Comparing those with to those without the MetS, the odds ratios (95%CI) for having a 10 year CVD risk ≥15% were 6.6 (5.4, 8.2), 5.5 (4.7, 6.5), 5.6 (4.8, 6.6), and 3.5 (3.0, 4.1), for the WHO, ATPIII, IDF, and EGIR definitions, respectively. The population attributable risk (PAR) of high CVD risk due to the MetS was highest for the IDF (23.4%). Insulin resistance was detected in 56.1, 69.7, 50.9, and 91.1% of those meeting the ATPIII, WHO, IDF, and EGIR definitions, respectively.

Conclusion :
The WHO definition was associated with the greatest CVD risk, but is not practical for clinical use. The higher PAR due to the IDF definition, with only slightly lower CVD risk than WHO, and clinical utility of the IDF definition, indicates that it may be a useful tool for CVD prevention.

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Background and purpose: Leptin predicts cardiovascular diseases and type 2 diabetes, diseases to which Asian Indians are highly susceptible. As a risk marker, leptin’s intra-individual and seasonal stability is unstudied and only small studies have compared leptin levels in Asian Indians with other populations. The aim of this study was to explore ethnicity related differences in leptin levels and its intra-individual and seasonal stability.

Methods: Leptin and anthropometric data from the northern Sweden MONICA (3513 Europids) and the Mauritius Non-communicable Disease (2480 Asian Indians and Creoles) studies were used. In both studies men and women, 25- to 74-year old, participated in both an initial population survey and a follow-up after 5–13 years. For the analysis of seasonal leptin variation, a subset of 1780 participants, 30- to 60-year old, in the Vasterbotten Intervention Project was used.

Results: Asian Indian men and women had higher levels of leptin, leptin per body mass index (BMI) unit (leptin/BMI) or per cm in waist circumference (WC; leptin/waist) than Creoles and Europids when adjusted for BMI (all P<0.0005) or WC (all P<0.005). In men, Creoles had higher leptin, leptin/BMI and leptin/waist than Europids when adjusted for BMI or WC (all P<0.0005). In women, Creoles had higher leptin/BMI and leptin/waist than Europids only when adjusted for WC (P<0.0005). Asian Indian ethnicity in both sexes, and Creole ethnicity in men, was independently associated with high leptin levels. The intra-class correlation for leptin was similar (0.6–0.7), independently of sex, ethnicity or follow-up time. No seasonal variation in leptin levels was seen.

Conclusion: Asian Indians have higher levels of leptin, leptin/BMI and leptin/waist than Creoles and Europids. Leptin has a high intra-individual stability and seasonal leptin variation does not appear to explain the ethnic differences observed here.

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While field and laboratory based studies have provided significant insights into the parental care and courtship behaviour of dendrobatoid frogs, a comprehensive assessment of their genetic mating systems and population genetic parameters has been precluded because ofthe lack of highly variable DNA markers. Here we document the development of nine novel polymorphic microsatellite markers for the dyeing poison frog Dendrobates tinct or ius (Dendrobatidae ). We found between three and 16 alleles per locus in 60 individuals (30 males, 30 females) from the field site Saut Parare, French Guiana, with an average observed heterozygosity of 0. 75. None of the loci deviated significantly from Hardy-Weinberg equilibrium or showed linkage disequilibrium. We also report successful cross-species amplification of the nine markers in two other dendrobatoid species (Allobates femora/is and Oophaga pumilio). These markers have the potential to aid in determining the genetic structure of local populations, identifying small-scale phylogenies such as parent-offspring relationships and will allow for cross-species comparisons within dendrobatoid species. Therefore, these markers can be applied to a wide range of scientific fields, such as conservation, behavioural ecology and evolutionary biology.

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The foraging benefits of coloniality, whereby colony members exchange information about food location, have been suggested as a primary factor influencing the evolution of coloniality. However, despite its longstanding popularity, this hypothesis has rarely been tested experimentally. Here, we conducted a field experiment in the wild Zebra Finch Taeniopygia guttata to test whether colonial birds are better at finding food than solitary individuals. We manipulated food patch location and directly measured foraging activity of many colonial and solitary parents at those patches using an electronic monitoring system. We provided nesting sites in excess to alleviate nest site competition and manipulated brood size to eliminate the possible correlation between brood size, nesting density, and individual quality (including foraging activity). We found that solitary birds found experimental food patches first, closely followed by colonial birds. Moreover, solitary parents adjusted the amount of food per nestling to experimental brood size, whereas colonial parents did not, although overall, nestlings were fed more per capita in colonial than in solitary nests. In addition, brood size and, to a lesser extent, nesting density negatively affected nestling growth. Therefore, with the effect of provisioning rate, sibling competition, and cost of coloniality combined, nestling mass was not affected by the brood manipulation in solitary nests, whereas nestlings were lighter in enlarged than in reduced broods in colonies. Our results therefore suggest that individuals settling in solitary nests were intrinsically better foragers and more optimal parents. While they do not invalidate the possibility of information transfer at colonies, our findings highlight the importance of considering settlement bias in future studies and add to the existing evidence that the effects of nesting density on fitness are both complex and multiple.

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The Australian Early Development Index (AEDI) is a teacher-administered measure that indicates if children are starting school with the developmental capacity to take advantage of the school learning environment. A key question that arises for schools, communities, and policy makers is how valid the AEDI is for children from a Language Background Other Than English (LBOTE). This study investigated how adequately the AEDI captures the cultural variety of different behaviours and different ways of learning. The study also examined the cultural inclusivity and relevance of the AEDI materials (e.g., teacher training guidelines; administration manual). Ten focus groups (n=84) and various community consultations were conducted with early childhood education and development professionals, representing key service providers, and school personnel. The findings from these studies led to the following recommendations: For LBOTE children, the AEDI should ideally be completed in collaboration, for example, between the child’s teacher and a multicultural consultant. The teacher guidelines for the AEDI need to be enhanced with respect to issues pertaining to LBOTE children, and the AEDI should include additional domains, such as cultural competence and home based/first language skills. Finally, teacher preparation and the AEDI administration guidelines need to clarify and emphasize the intent of the AEDI.

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The epidemiology of invasive fungal disease (IFD) due to filamentous fungi other than Aspergillus may be changing. We analysed clinical, microbiological and outcome data in Australian patients to determine the predisposing factors and identify determinants of mortality. Proven and probable non-Aspergillus mould infections (defined according to modified European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria) from 2004 to 2012 were evaluated in a multicentre study. Variables associated with infection and mortality were determined. Of 162 episodes of non-Aspergillus IFD, 145 (89.5%) were proven infections and 17 (10.5%) were probable infections. The pathogens included 29 fungal species/species complexes; mucormycetes (45.7%) and Scedosporium species (33.3%) were most common. The commonest comorbidities were haematological malignancies (HMs) (46.3%) diabetes mellitus (23.5%), and chronic pulmonary disease (16%); antecedent trauma was present in 21% of cases. Twenty-five (15.4%) patients had no immunocompromised status or comorbidity, and were more likely to have acquired infection following major trauma (p <0.01); 61 (37.7%) of cases affected patients without HMs or transplantation. Antifungal therapy was administered to 93.2% of patients (median 68 days, interquartile range 19-275), and adjunctive surgery was performed in 58.6%. The all-cause 90-day mortality was 44.4%; HMs and intensive-care admission were the strongest predictors of death (both p <0.001). Survival varied by fungal group, with the risk of death being significantly lower in patients with dematiaceous mould infections than in patients with other non-Aspergillus mould infections. Non-Aspergillus IFD affected diverse patient groups, including non-immunocompromised hosts and those outside traditional risk groups; therefore, definitions of IFD in these patients are required. Given the high mortality, increased recognition of infections and accurate identification of the causative agent are required.

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A review of the technological innovation adoption literature on small to medium-sized enterprises (SMEs) provides useful insights into factors influencing innovation adoption but points to the need to introduce more determinants of innovation adoption to SMEs research. This research is interested in identifying these factors and hence, introducing more potential determinants to electronic commerce (EC) adoption research in SMEs. Therefore, this research attempts to extend the technological innovation theories to EC adoption research in SMEs by identifying potential constructs and factors from these theories and then checking their face validity using three case studies in New Zealand. This research endeavours to shortlist and discuss the most important determinants of EC adoption and to eliminate the least relevant ones.

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Purpose – Models of workplace turnover are rarely assessed in contexts other than that in which they were developed. This reduces their generalizability and their usefulness in providing managers with guidance as to what they might do to reduce workers intentions to quit. The purpose of this study is to test a model derived from a study of shop floor retail salespeople in the call centre environment.

Design/methodology/approach – A questionnaire measuring the variables in the model was completed by 126 call centre representatives recruited from 11 call centres in Melbourne, Australia.

Findings – Although the model was supported, the interactions among the variables differed. In particular, stressors played a bigger, albeit indirect, role in the intention to quit.

Practical implications – Call centre managers need to consider carefully the aspects of the work environment that may be stressful. If appropriately addressed, turnover may be reduced, and productivity increased.

Originality/value – This paper demonstrates that the model of turnover derived from shop floor salespeople is generally robust in the call centre setting. It provides management of call centres with some guidance as to the factors associated with turnover and areas that can be addressed to reduce it.

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Government policy in Australia is increasingly encouraging training organisations in the Vocational Education and Training (VET) sector to adopt flexible delivery approaches, but some researchers are sounding a note of caution. Evidence is emerging that Australian VET learners are not universally ready for flexible delivery, and this is reflected in high attrition rates and low pass rates. The literature on flexible delivery identifies a number of specific factors that can impact on the success of adult learners. However, there seems to be agreement that failure or dropout is not determined by a single factor, but by the interaction of a number of factors that build up over time. To understand these factors, we need to understand the learners - what their participation in education means to them, the context in which they are studying, and the numerous inter-connected factors that contribute to their failure to achieve a successful outcome. This paper discusses four case studies from a research project that followed up a small number of adult learners who enrolled in flexible delivery VET courses but did not achieve a successful outcome.