84,021 research outputs found
Credit Risk in Islamic and Conventional Banks
No full textThis thesis investigates several aspects concerning the financial stability of Islamic and conventional banks. This is important because the strong growth of Islamic banking, notwithstanding their marked uniqueness in operational and financing behaviour, combined with fierce global competition with the prevailing conventional bank system, raises concerns among regulators and practitioners about the long-run sustainability of Islamic banking. First, the thesis compares the level of financial stability in Islamic and conventional banks using three different methods of credit risk measurement. Second, it compares the effect of competition on stability across Islamic and conventional banks. Finally, it investigates whether efficiency significantly modulates the linkage between competition and stability in both Islamic and conventional banks.
In the first research question, the thesis considers the levels of credit risk in Islamic and conventional banks, for which existing literature finds no conclusive result. One problem with existing studies is the use of accounting information alone to assess credit risk and this could be especially misleading with Islamic banking. Using a market-based credit risk measure, namely, Merton’s distance-to-default (DD) model, we evaluate the credit risk of 156 conventional and 37 Islamic banks across 13 countries between 2000 and 2012. We also calculate the accounting information-based Z-score and nonperforming loan (NPL) ratio for the purpose of comparison. The results show that Islamic banks have significantly lower credit risk than conventional banks as based on DD. In contrast, and as expected, Islamic banks display much higher credit risk using the Z-score and NPL ratio. These findings suggest that the measure chosen plays a significant role in assessing the actual credit risk of Islamic banks.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Griffith Business SchoolGriffith Business SchoolFull Tex
The meaning of work for Gen Z hospitality workers
No full textWork is considered by many as a vital aspect of human existence, not only by providing an income but also giving purpose and direction to their lives. Work has evolved over the many years of human existence, and every few decades, a new generation emerges and replaces the previous generation in the labour market. Understandings of the meaning of work are the product of decades of tradition and inquiry across several disciplines.
With the rise of each generation of young workers there is a lack of understanding about what work means to them and how this new cohort perceives work. This is specifically relative as industries worldwide and the current emergent workforce are severely struck by a great disruption caused by the COVID-19 global pandemic. Motivated by developments, the aims of this study are to investigate the meaning of work held by young hospitality workers and the different ways in which they perceive work, and how their meaning of work affects the way they view their work and job.
The research analyses how work has developed to its current form and reviews the meaning of work in literature in order to show what meanings and avenues have been uncovered and what tools were used to explore meaning. Adopting a qualitative lens, this study collected data through several focus groups followed by a series of semi-structured interviews using a sample that represent young workers, who are currently being referred to in some literature as Gen Z, and work in the Australian hospitality industry. The findings provide insights on the current sources of meaning, the different conceptualisation of work and how the meaning of work is perceived in the 21st century. [...]Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Dept Tourism, Sport & Hot MgmtGriffith Business SchoolFull Tex
Value of Small Seagrass Patches as Tidal Flow-Refuges
No full textOne central challenge in the study of seagrass meadows is explaining the abundance and diversity of nekton associated with these productive habitats. While many models have been proposed to explain fish use of seagrass habitats, mainly focusing on their nursery and predator-avoidance values based on the complex habitat structure, most empirical studies were conducted on relatively large patches using catch data collected from invasive capture methods. Seagrass meadows on peri-urban coasts, however, continually being threatened and fragmented, while invasive surveying techniques could bias fish abundance data. This thesis aims to determine if small remnant Zostera capricorni patches in a peri-urban estuary provide small mobile fish with a flow-refuge within a strong tidal flow environment, using non-invasive video surveying techniques to monitor fish abundance and behaviour.
The hydrodynamic characteristics of three small patches of Z. capricorni were measured using in situ deployment of Acoustic Doppler Current Profilers (ADCP) at the front and rear of the patches during tidal current flow between 20 and 30 cm/s. Seagrass canopies of densities and morphologies covered by these patches significantly baffled the free-stream flow (X), creating a near-zero, turbulent free, within-canopy hydraulic environment 0.25m from the canopy’s leading edge. Flows were deflected over the canopy surface causing the leaves to bend, compressing the canopy and thereby reducing the vertical flux under high flows. While lower flows were still significantly reduced, a small vertical flux occurred, with large turbulent eddies generating from the canopy friction. The hydraulic environment behind the patch was significantly different to that at the patch’s front – characterised by near zero flows and turbulent fluctuations (at 0m), and flow velocities increasing with downstream distance. This effect was noticeable due to the velocity above the canopy being significantly reduced from flows above the canopy (fast). This difference diminished with downstream distance, gradually resembling the front profile. The rear environment close to the patch edge matched those of other flow-refuges.Thesis (Masters)Master of Philosophy (MPhil)Griffith School of EnvironmentScience, Environment, Engineering and TechnologyFull Tex
Optimization of cyanobacteria bloom management through improved forecasting models and optical sensors
No full textCyanobacteria are a diverse group of microorganisms adapted to a range of environmental conditions that favour their ubiquity in waterbodies. Cyanobacteria harmful blooms (CyanoHABs) are events in which a cyanobacteria population grows rapidly, dominates the phytoplankton community and may release toxins or other noxious compounds in the waterbody. The frequency and magnitude of CyanoHABs are increasing as a result of climate change and increased pollution from urbanisation and agriculture expansion, representing a major risk to the public health and economy. Management of CyanoHABs is complicated by the temporal and spatial dynamic nature of these events, and by the large diversity of cyanobacteria species. Identification of the dominant cyanobacteria species is required to select appropriate mitigation and treatment alternatives. Therefore, water authorities have longed for reliable tools to support proactive and species-targeted CyanoHAB management. Emerging monitoring technologies and data-driven models represent a tangible opportunity to optimise CyanoHABs management by integrating rapid and taxa precise features into a single tool. Optical sensors, namely in-situ fluorescence sensors, allow rapid, remote estimation of the total phytoplankton and cyanobacteria concentration in a waterbody. This is done by measuring the fluorescence of the pigments chlorophyll a, common to all phytoplankton, and phycocyanin, exclusive to cyanobacteria. However, fluorescence estimates have limited taxa precision because they cannot discriminate between cyanobacteria species, and may have reduced accuracy, due to optical interferences. Data-driven models are increasingly being used to understand and predict complex ecological patterns, including cyanobacteria species succession, but the combination of high-frequency fluorescence data with data-driven models to optimise CyanoHAB management has seldom been investigated.
The aim of this doctoral thesis is to develop an integrated model able to optimise CyanoHAB management by incorporating site-specific drivers of cyanobacteria succession and factors that affect fluorescence sensor estimates. This aim was achieved by addressing four objectives: (1) to systematically review the state-of-knowledge of forecasting and predictive CyanoHAB models and their application to freshwater lakes; (2) to test and quantify interferences, if any, on fluorescence probe measurements according to diel light variability and species composition; (3) to identify and quantify, through observational data analysis, dominance of cyanobacteria species according to site-specific environmental conditions; and (4) to establish a framework for implementation of integrated models considering fluorescence sensor calibration and prediction of cyanobacteria species succession.
This research project’s combination of observational data analysis and analytical laboratory work underpins its novelty and relevance. Observational data analysis was performed for three Australian drinking-water reservoirs and correlations between environmental drivers and dominance of key cyanobacteria species were determined for Wivenhoe Lake (Queensland), Tingalpa Reservoir (Queensland) and Myponga Reservoir (South Australia). Two sets of controlled laboratory experiments were then performed. The first experiment analysed the fluorescence characteristics of four key cyanobacteria species (Aphanocapsa sp., Microcystis aeruginosa, Dolichospermum circinale and Raphidiopsis raciborskii) that are often dominant in the assessed drinking-water reservoirs. The experiment quantified the variability of the species’ fluorescence characteristics throughout their respective growth phases and also compared the differences among morphologically similar species. The second experiment analysed light-induced quenching in a cyanobacterium (Dolichospermum variabilis) and a green alga (Ankistrodesmus gracilis) by simulating diel light variability under controlled temperature and stratification conditions. Lastly, a framework combining the methodological procedures from the observational data analysis and the fluorescence calibration experiments was established with the aim of supporting the development of species-targeted models utilizing fluorescence sensors. An integrated model based on the framework was developed and tested in Myponga Reservoir, South Australia. Moreover, a continuous improvement process for CyanoHAB models and guidelines of best practices for fluorescence sensors deployment, calibration and operation were developed as a result of this research.
The methods and findings are provided in four peer-reviewed journal papers included as chapters in this thesis (i.e., chapters 3, 5, 6 and 7) and a final discussion chapter (chapter 8). Objective 1 findings revealed that high-frequency data, such as the data from optical sensors, can improve performance of CyanoHAB models. For Objective 2, two key findings should be highlighted. First, fluorescence per cell was found to significantly vary among species, while fluorescence per unit of biomass (estimated from biovolume) was much more consistent among species. Second, diel light variability reduced fluorescence for both cyanobacteria and green algae up to 79% under the assessed conditions. Objective 3 findings indicated that environmental drivers for cyanobacteria succession and dominance are mostly site-specific. Species-specific traits, such as diazotrophy and gas vesicles, interact in complex ways with local environmental conditions leading to variable dominance succession among species. Finally, the key findings of Objective 4 showed that the required steps to develop a species-targeted CyanoHAB model using fluorescence sensors are feasible, given that constraints in data availability are met. Overall, the findings of this PhD research indicate that CyanoHAB management can be optimised through the combination of fluorescence sensors and forecasting models based on data-driven approaches, as long as rigorous calibration and data analysis procedures are undertaken. Importantly, the findings also highlight that even though generalisable patterns of species-specific drivers exist, site-specific analysis is required due to the complex interactions between the several factors involved in the occurrence of CyanoHABs.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Eng & Built EnvScience, Environment, Engineering and TechnologyFull Tex
Self-Regulatory Responses to Positive Career Goal Discrepancies in Young Adults
No full textThis thesis focused on positive career goal discrepancies, informed by self-regulatory theories. A positive goal discrepancy is the individual's perception that current performance exceeds the set goal. Prior research has focused on understanding and finding solutions to negative career goal discrepancies (performance falls short of goals). However, understanding positive discrepancies is essential for improving young adults’ career development, where maximising and developing individual potential is one of the main goals. Positive and negative goal discrepancies are not simply opposites as they trigger different changes in the self-regulatory process and have different underlying mechanisms and boundary conditions. This thesis expanded research in the career literature by addressing three objectives: (a) to develop and validate a new scale to measure positive career goal discrepancy, (b) to assess the antecedents and outcomes of positive career goal discrepancy and test whether it provided an explanatory mechanism through which antecedents were related to cognitive and affective outcomes, and (c) to understand how changes in positive career goal discrepancy were related to adjustments in career goals and behaviours. These objectives were addressed through three empirical studies, which have been published in, or is currently under review with peer-reviewed journal. Participants for all studies were first-year university students from a collectivist cultural context (i.e., Indonesia). [...]Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Applied PsychologyGriffith HealthFull Tex
Impaired surface expression of Transient Receptor Potential Melastatin 2 and 3 ion channels lowers Natural Killer Cell Cytotoxic Activity in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
No full textMyalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) is a disabling condition characterised by unexplained chronic fatigue that is associated with immune, neurological (including autonomic), musculoskeletal, cardiovascular and gastrointestinal symptoms [1, 2]. Currently, accurate diagnosis remains challenging in the absence of a clinical or laboratory test. Although the aetiology of ME/CFS remains undefined, a significant reduction in natural killer (NK) cell cytotoxicity is consistently reported in ME/CFS patients compared with healthy controls (HC) [3-6]. NK cells are effector lymphocytes of the innate immune system principally responsible for recognising and responding to pathogen invasion [7]. Approximately 90% of peripheral NK cells are CD56DimCD16+ which are highly cytotoxic and kill infected, tumour or ‘missing self’ cells through cytotoxic processes [8]. Conversely, the CD56BrightCD16Dim/- subset is responsible for immunosurveillance and cytokine production [9]. Importantly, NK cells require calcium (Ca2+) to regulate various cellular functions, such as cell differentiation, cell division, apoptosis, transcription, and cytotoxicity [10].
Transient Receptor Potential (TRP) channels are a group of unique ion channels whereby majority are highly selective to Ca2+ [11]. Functionally, TRP ion channels regulate “threat” stimuli, such as pain, thermosensation, mechanosensation, pathogens, and chemicals, via sensory transduction pathways. TRPM2 and TRPM3 are cation channels ubiquitously expressed throughout the human body and expressed in almost all cell types, such as NK cells. Both TRPM members are highly permeable to Ca2+, therefore are critical regulators of Ca2+-dependent pathways, such as NK cell cytotoxicity. TRPM2 is activated by adenine dinucleotides (ADPR, cADPR, NAADP, ꞵ-NAD), reactive oxygen species (hydrogen peroxide and OH-), and intracellular ([Ca2+]i). Conversely, TRPM3 is potently activated by neural steroids, such as pregnenolone sulphate (PregS) and nifedipine. Upon stimulation, TRPM2 and TRPM3 ion channels trigger a rapid influx of Ca2+ influx and rise in [Ca2+]i, which subsequently facilitates intracellular pathways for Ca2+ release from cellular organelles.
Recently, TRPM2 has emerged as a key receptor in mediating Ca2+-induced anti-tumour activity in mouse NK cells via synergistic activation with CD38. CD38 generates Ca2+ mobilizing secondary messengers, such as ADPR, to activate TRPM2. Rah et al., determined inhibition of sustained tumour-induced Ca2+ signals and degranulation in mouse NK cells following 8-bromoadenosine diphosphoribose (8-Br-ADPR) treatment [12]. Moreover, N6-Benzoyladenosine-3′,5′-cyclic monophosphate (N6-Bnz-cAMP) significantly increased intracellular ADPR, however was inhibited in Ca2+-free conditions [12]. Currently, no in vitro studies have examined the phenotype and function of TRPM2 ion channels on human NK cell subsets, notably in ME/CFS research. Conversely, five single nucleotide polymorphisms in NK cells associated with TRPM3 have been previously identified in ME/CFS patients [13]. Reduced TRPM3 surface expression and impaired Ca2+ influx has furthermore been identified on NK cells in ME/CFS patients [14].
Given TRPM2 and TRPM3 are both critical regulators for Ca2+ signalling in NK cells, the overall aim of this thesis was to investigate the role of TRPM2 and TRPM3 in mediating NK cell cytotoxicity to identify a potential mechanism of reduced NK cell cytotoxic activity in ME/CFS patients. Study one aimed to develop an in vitro methodology to characterise TRPM2 and CD38 surface expression on NK cell subsets using an antibody that has not been previously used with flow cytometry. Applying this optimised methodology, study two aimed to quantify TRPM2 and CD38 surface expression on NK cell subsets at baseline and post in vitro drug treatments (N6-Bnz-cAMP and 8-Br-ADPR) in ME/CFS patients and HC. NK cell cytotoxicity was furthermore measured at baseline and post in vitro drug treatments (N6-Bnz-cAMP and 8-Br-ADPR) between groups. Lastly, study three aimed to examine the clinical presentation in a moderate-severe ME/CFS group, as well as measure NK cell cytotoxicity post in vitro drug treatment with TRPM3 agonists, PregS, nifedipine and ononetin, in ME/CFS patients and HC.
Age and sex matched HC were included in study one. Age and sex-matched ME/CFS patients meeting the Canadian Consensus Criteria (CCC) and HC were included in studies two and three. All participants donated 85ml of whole blood and peripheral NK cells were isolated. TRPM2 and CD38 surface expression was measured on CD56DimCD16+ and CD56BrightCD16Dim/- subsets, as well as NK cell cytotoxicity at baseline and post in vitro drug treatments by flow cytometry. Drug treatments included: interleukin-2, N6-Bnz-cAMP, 8-Br-ADPR, PregS, nifedipine and ononetin.
Study one determined 1:50 as the optimal primary TRPM2 antibody dilution following a two-hour incubation period. TRPM2 surface expression with and without CD38 co-expression significantly increased between 1:300 and 1:50 primary TRPM2 antibody dilutions following a two-hour incubation period on both CD56DimCD16+ and CD56BrightCD16Dim/- NK cell subsets. On the CD56DimCD16+ subset only, TRPM2 and CD38 surface expression also significantly increased at 1:50 compared with 1:100. Moreover, TRPM2 surface expression significantly decreased between 1:50 and 1:5 TRPM2 antibody dilution following a two-hour incubation period. This significant decrease highlights the high-dose hook effect, whereby the highly concentrated 1:5 antibody dilution saturated both capture and detection TRPM2 antibodies. Study two identified a significant overexpression of the TRPM2 ion channel on NK cell subsets in ME/CFS patients compared with HC. No significant differences in NK cell cytotoxicity were observed between or within groups post N6-Bnz-cAMP and 8-Br-ADPR drug treatments.
Lastly, study three revealed no signficiant differences in NK cell cytotoxicity post PregS and nifedipine drug treatments, as well as subsequent blocking with ononentin in both groups. In both Study 2 and Study 3, viral infections and various clinical ME/CFS symptoms were significantly associated with reduced NK cell cytotoxicity in ME/CFS patients. Associations included: pain, cognitive difficulties, sleep disturbances, sensory impairments, thermostatic instability and gastrointestinal disturbances, possibly involving TRPM2 and TRPM3.
In conclusion, the results of this thesis are the first to develop a novel and optimal in vitro methodology to measure TRPM2 and CD38 surface expression on human NK cell subsets using flow cytometry. This thesis is also the first to report overexpressed TRPM2 ion channels on NK cell subsets in ME/CFS patients. Oxidative stress induced by viral infections is hypothesised to cause this overexpression in TRPM2 ion channels in ME/CFS patients as previously reported. Overexpressed TRPM2 ion channels may cause mitochondrial dysfunction, cellular death, DNA damage, and disruption to MAPK pathways following uncontrolled increases in [Ca2+]i. Collectively, these processes interfere with downstream Ca2+-dependent pathways, such as NK cell cytotoxicity, which was found to be significantly reduced at baseline in ME/CFS patients compared to HC.
The drug-treated NK cell cytotoxicity results may reflect the sensitivity of the cytotoxic assay to capture the TRPM2 and TRPM3 drug-modulatory effects on NK cell cytotoxicity. Given the drugs were incubated in the media and cells for more than 24 hours, the TRPM2 and TRPM3 ion channels may have undergone repetitive activation and inhibition cycles. Consequently, this may have activated and caused sustained long-term Ca2+-dependent pathways which may have potentially resulted in disrupted gene expression, irreversible cellular death and the development of NK cell hyporesponsiveness.
Furthermore, a primary limitation with TRPM2 is the lack of potent and specific pharmacological tools. Consequently, the TRPM2 signals may have been reduced or lost, subsequently modulating activation of downstream NK cell cytotoxic processes, such as the extracellular signal-regulated protein kinase 1/2 and mitogen-activated protein kinase pathways. Taken together, this thesis warrants the identification of additional experiments with a more appropriate time-sensitivity to capture the pharmacological effects of specific cellular mechanisms of interest, as well as the identification and development of more potent, specific, and non-toxic pharmacological tools targeting TRPM2. Additional rationales include co-localisation of between TRPM2 and CD38 and the involvement of TRPM2 and TRPM3 spliced isoforms.
A common feature shared amongst the significant associations between reduced NK cell cytotoxicity clinical ME/CFS symptoms is the high expression and functional activity of TRPM2 and TRPM3 in the CNS, which functions as the control centre for these physiological systems. However, additional quantitative tests examining these clinical functions, such as nociceptive pain and thermoregulation, are required to definitvely associate the possible roles of TRPM2 and TRPM3 activity and the unique clinical presentation of ME/CFS. Interestingly, positive correlations were determined between reduced NK cell cytotoxicity and overexpressed TRPM2 ion channels on both NK cell subsets within the ME/CFS group. ROC analyses also revealed diagnostic potential for reduced NK cell cytotoxicity and overexpressed TRPM2 ion channels in ME/CFS patients. Collectively, these results highlight a relationship between TRPM2 and reduced NK cell cytotoxicity in ME/CFS. Therefore, furthur investigations in this vital area of ME/CFS research will assist in the validation of TRPM2 and TRPM3 as potential biological markers to further understand the unique pathomechanism of ME/CFS and facilitate the development of targeted therapeutic interventions to improve the quality of life of ME/CFS patients.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Medical ScienceGriffith HealthFull Tex
Emotional Well-Being of Childbearibg Women: A Comparision of Nationals and Foreign Brides in Taiwan
No full textAbstract :This study surveyed a total of 236 Taiwanese and 44 foreign-born Vietnamese women in four antenatal clinics located in Pingtung County, the southern part of Taiwan. Participants provided demographic details and completed various standardized measures, including Difficult Life Circumstances (DLC), Social Support (SSA), Rosenberg Self-Esteem (RSE), General Health Questionnaire-12 (GHQ-12), Depression Anxiety Stress Scale-21 (DASS-21), and Edinburgh Depression Scale (EDS, a antenatal version of the Edinburgh Postnatal Depression Scale; EPDS). Six weeks after birth, all eligible participants completed follow-up questionnaires including the Child Care Stress Checklist (CCSC) and the same set of scales used antenatally (SSA, GHQ-12, DASS-21, and EPDS). The Vietnamese and Chinese versions of each scale were provided as appropriate. Participating women with EPDS scores of 13 or more were classified as having probable depression. According to this classification, the prevalence rate of antenatal depression among foreign born Vietnamese women was higher (31.8%) than that observed in their Taiwanese counterparts (17.3%), the difference between the two cohorts was statistically significant (Mann-Whitney U test = 2574, Z = -2.84, p .05). For Taiwanese women, several antenatal variables were found to contribute to the development of depressive symptoms. These included mixed feelings towards the pregnancy, Difficult Life Circumstances (DLC), social support (SSA), self-esteem (RSE), and psychological distress (DASS-21 & GHQ-12). At 6 weeks postpartum, positive statistical associations between antenatal and postnatal depressive symptoms were found. In addition, women experiencing more childcare stress (CCSC) and more psychological distress (DASS-21 & GHQ-12) were more likely to develop PND. There was a negative association between social support (SSA) and PND. Overall, these four variables; antenatal depressive symptoms, GHQ-12, CCSC, and SSA, explained 68% of variance of PND and similar results were found for Vietnamese women. In comparison with Taiwanese nationals, Vietnamese women showed lower scores for social support (SSA) and higher scores on DLC, CCSC, DASS-21, and GHQ-12 both during pregnancy and the postpartum. This study provides valuable insights into the emotional well-being of childbearing Taiwanese women and a small cohort of new immigrant women in Taiwan. The thesis highlights the difficulties of recruiting and engaging minority groups in social research. Barriers related not only to language but their status in the community, dependence on their spouse, and difficulty accessing health care services. Results of the current study provide an understanding of the experiences and perceptions of contemporary birthing women in Taiwan and highlight the difficulties experienced by immigrant women in that country. The findings of this study should prompt health care providers to undertake careful assessments of expectant mothers for depression and related problems, as well as offering prevention and intervention activities to promote maternal psychological well-being.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Griffith University. School of Nursing and Midwifery.Griffith HealthFull Tex
Relationships among Muscle Fibre Typology, the Force-Velocity-Power relationship, and the Force-velocity profile during the Squat Jump and Sprinting
No full textBackground: Sport Science researchers have validated a novel methodology to determine the force-velocity profile (SFv) which can be optimized in the vertical profile to maximise an athlete’s power production. This profile represents an extension upon the well-known force-velocity-power relationship (FVPr) which is based on the 1938 Hill model. Early muscle physiology researchers identified that different skeletal muscle fiber typology (MFT) exist and have categorized these fiber types according to contractile characteristics, enzyme activities, morphological, and metabolic properties. The physiological characteristics between MFT display differences in maximum shortening velocity and time to fatigue, which results in contrasting force-velocity-power (FVP) production capabilities during exercise. Human MFT is thought to be largely determined genetically, with little influence from external stimulus (i.e., exercise training), leading to a predisposition for sporting success along a sporting domain spectrum, from sprint to endurance sports. Within elite sport, athletes are tested for jumping and sprinting performance to determine; the suitability of an athlete to a given sport, identify the needs of an athlete, the responses to training, and preparedness of athletes for elite competition. Much research has investigated the FVPr variables and the SFv during jumping and sprinting. To date however, research is yet to investigate important relationships among MFT, the FVPr, and the SFv during jumping and sprinting. As such, further experimental research is required to determine such relationships, and provide important implications for performance professionals and researchers alike.
Objectives: The primary objective of the research study was to to investigate apparent relationships between MFT and the mechanical variables of the SFv and the FVPr during the squat jump and sprinting. A secondary aim was to consider how those relationships may influence exercise performance.
Methodology: Nineteen developing rugby league (RL) athletes were assessed for MFT, as well as the mechanical variables derived from the force- velocity-power (FVP) profiles during the squat jump and sprinting. The FVPr and SFv mechanical variables were acquired by using the computational method for both jumping and sprinting. For jumping, the participants were required to complete a series of un-loaded and loaded barbell squat jumps, whereby the highest jump from each trial was used to determine the jumping FVPr and SFv. For sprinting, two trials of 30 m sprints were completed, whereby split times were recorded at 5 m intervals. The fastest trial from each participant was used to determine the sprinting FVPr, SFv, and mechanical application of force variables. Proton magnetic resonance spectroscopy (1H-MRS) was used to quantify carnosine concentration in the gastrocnemius muscle in order to estimate MFT. The carnosine concentration was compared to that of a control population of active, non-athlete males (n=40), whereby an individual carnosine Z-score was derived for the RL athletes. Carnosine Z-score MFT groups were formed using the known group difference technique, whereby all carnosine Z-scores above zero formed the positive carnosine MFT group (n=9), and below zero formed the negative carnosine MFT group (n=10). SPSS (v26) was used to perform t-tests and spearman’s correlations to determine significant differences and relationships between carnosine Z-score MFT groups and the mechanical variables, while Microsoft Office Excel (2016) was used to analyse group variables data (sample size, mean, and standard deviation) acquired by the t-tests, to calculate Cohen’s d effects size.
Results: MFT was not found to influence the SFv during jumping or sprinting, however, MFT was found to influence the FVPr, with differences for force, velocity, and power between MFT. Moderate associations were also found between carnosine Z-score and the mechanical variables (force-velocity-power). Maximal power output (PMAX) was significantly different between carnosine Z-score MFT groups during jumping (p= 0.041, d=1.01), and was moderately associated with MFT (r=0.598**). PMAX (W/kg) was thought to be most influenced by VO (m/s) (p=0.073, d=0.88) but not FO (N/kg) during the squat jump. FO (N/kg) was not significantly different between groups (p=0.920, d=0.05) and had a negligible association with MFT (r= -0.032). During sprinting the SFv was not significantly different between groups (p=0.224, d=0.58) and was not considered to be influenced by MFT (r= -0.053). PMAX (W/kg) during sprinting was found to have a significant difference between MFT groups (p=<0.001, d=2.12), and seemed to be most influenced by FO (N/kg) (r=0.858**). FO (N/kg) was also significantly different between groups (p=0.019, d=1.19), while VO was not (p=0.216, d=0.59), and VO had a low association to PMAX (r=0.030). PMAX was found to influence RFMAX with a very high correlation (r=0.993**) and RFMAX was found to be significantly different between MFT groups (p=0.001, d=1.97). Exercise performance was most associated with PMAX in both jump height (m) (r=0.801**) and 30-m sprint time (s) (r=-0.893**), and resulted in significant and highly significant differences between groups for the squat jump (p=0.038, d=1.03) and the 30-m sprint time (s) (p=<0.001, d=2.54).
Conclusion: Variation in MFT was not associated with variation in the SFv during the squat jump or sprinting, despite being associated with various mechanical variables derived from the FVPr. MFT was found to influence PMAX differently during the squat jump when compared to sprinting. This is thought to be due to the low velocity constraints of the Squat jump, compared to the high velocity motion of sprinting, which highlights the difference in force production capabilities at high velocities for type IIa/ IIx MFT (Aagaard & Andersen, 1998; Tihanyi, Apor, & Fekete, 1982). The magnitude of difference between PMAX (W/kg) in sprinting when compared to the squat jump supports this inference, and is thought (Aagaard & Andersen, 1998; Tihanyi et al., 1982) to have occurred due to the low velocity constraints during the squat jump. To confirm this finding, future studies investigating associations between MFT and the FVPr, should compare FVP mechanical variables between the squat jump and high velocity jumps, such as a counter movement jump or drop jump. Future research should also aim to determine PMAX (W/kg) thresholds as associated to carnosine Z-score to better advise practitioners in the field; during baseline testing, with exercise prescription, during athlete performance monitoring, and determining athlete suitability for elite sport. While this study has determined an association between MFT, the FVPr, and has demonstrated that MFT has likely influenced the associated exercise performance. It is possible other muscle morphology differences within these groups (pennation angle and cross-sectional area), may also contribute to performance differences found, and is a recommendation for future investigation.Thesis (Masters)Master of Medical Research (MMedRes)School of Medical ScienceGriffith HealthFull Tex
The association between skeletal muscle fibre typology external load during elite Australian Football match-play
No full textIntroduction: Skeletal muscle fibre typology (MFT) directly influences a muscle's contraction speed and fatigue profile both during and following exercise. MFT of a given muscle can vary dramatically between individuals and is largely determined hereditarily. Furthermore, MFT is associated with an athlete's suitability to a sport/event and is suggested as a determining factor for separating elite athletes, from their sub-elite counterparts in sprint and endurance sporting disciplines. Despite these important characteristics, there is limited research on the MFT of team-sport athletes and the impact this may have on performance. The invasive nature of the muscle biopsy, the gold standard of MFT determination, has shielded research investigating the MFT of professional team-sport athletes. Recently validated, non-invasive measures to estimate MFT, through the use of magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS), may renew the interest of MFT in team-sport athletes. Australian football (AF) is a team sport that requires athletes to cover large distances at varying speeds and intensities. External load is a quantification of the work performed by an athlete (i.e. distance travelled, distance travelled at high speeds, etc.). It is important to quantify external loads achieved during match-play as this will provide relevant data on the specific movement profiles of competition and may assist in the development of AFL-specific conditioning programs, testing protocols as well as team recruitment and selection. Numerous contextual factors have an influence on the external loads a professional AF athlete achieves during match-paly; position, physical characteristics, and conceivably, their MFT. Preliminary findings in elite soccer athletes have suggested that athletes with a higher proportion of type II fibres will achieve reduced distance sprinting (> 6.67 m×s-1), have a reduced peak 1-min sprint period, and display a larger decrement in high-speed running (HSR) (> 4.17 m×s-1) from the first to the second half of match-play. Despite these findings stemming from an elite team-sport cohort, more research is required on a larger cohort, across an entire season, and in the sport of AF, due to the difference in the external loads of match-play. Further investigation may determine whether such findings are true across different team sports, such that a particular MFT may achieve higher external loads during match-play of some variable and therefore may be predictive of success in a sport, be better suited to a position, or require a higher degree of fatigue management during match-play. As such, further investigation is required to determine if similar findings can be made in AF, which can provide novel and impactful information to practitioners and researchers alike.
Aim: The primary aim of this research study was to investigate the association between MFT and different variables pertaining to the external loads achieved during professional AF match-play. Secondary aims include; quantifying the MFT of professional AF athletes and quantify the external-loads of match-play during professional AF.
Methods: Twenty-four professional AF athletes were characterised by position (smalls, talls, and hybrids), differences in anthropometrics (height, body mass, and body composition), and physical (muscular strength, power, and endurance) and physiological characteristics (MFT) were determined. 1H-MRS was used to quantify intramuscular carnosine content in the soleus and gastrocnemius muscles and expressed as a Z-score relative to an age and gender-matched non-athlete population to estimate MFT. A more negative Z-score is predictive of a higher proportion of type I fibres, while a more positive Z-score is predictive of a higher proportion of type II fibres. External load during matchplay was collected using portable global navigational satellite system (GNSS) units (n = 224 matches). Data were extracted following each session from proprietary software, onto a customised statistical software. External load was expressed as a peak period of matchplay, determined using the maximal mean method. Power law was used to calculate the decrement in intensity with time, expressed as intercept (peak value) and slope (decrement over time). R software was used to perform ANOVA and linear mixed model analyses to determine; i) differences in MFT between playing position groups ii) differences in external loads in match-play between positions, and iii) the association between match-play external load and MFT. Microsoft excel was used to collate data and calculate group means, as well as calculate 95 % confidence intervals from linear mixed models results.
Results: MFT of the gastrocnemius and soleus was significantly associated with HSR (>4.17 m×s-1) distance (soleus; p = 0.013, gastrocnemius; p < 0.001), and HSR slope (soleus; p = 0.021, gastrocnemius; p < 0.001). The cohort presented with a large range of Z-scores across both gastrocnemius (min -1.83, max 0.81) and soleus (min -2.06, max 1.88), with a greater affinity for negative Z-scores (gastrocnemius; 17/24, 70.1 %, soleus; 19/24, 79.2 %). Talls spent a greater duration on the ground than both smalls and hybrids (p = 0.027), while hybrids averaged 16 m×min-1 greater speed than talls (p = 0.001) as well as ~800 m more distance covered in HSR (p < 0.001). Hybrids had the largest intercept for speed, HSR, and acceleration, however only significantly greater than talls for speed intercept (p = 0.006).
Conclusion: MFT appears to influence a professional AF athlete's HSR distance achieved within a match, as well as their HSR slope across peak periods of play. A high proportion of negative Z-scores were found within the cohort. These findings are similar to previous research investigating the influence of MFT on variables describing high intensity running in elite soccer athletes. These cross-sport similarities strengthen the rationale to continue investigations on the effect of MFT on team sport athletes. The high proportion of negative Z-scores reflects the high endurance capacity and load tolerance that the sport of AF demands, conceivably suggesting that athletes with high proportions of type II fibres may not fit the ideal phenotype for the sport. As has been established previously, external loads of match-play exhibited positional differences, with hybrids typically achieving the greatest loads. This information highlights the need for practitioners to individualise training prescription on a positional basis for both load and intensity. Future research should investigate the association between MFT and team sport athlete's ability to recover from exercise, which seems to be the likely cause of the difference observed in MFT for HSR. This information will empower practitioners to better manage athletes' recovery within a match and throughout a pre-season period.Thesis (Masters)Master of Medical Research (MMedRes)School of Pharmacy & Med SciGriffith HealthFull Tex
Corporate Social Responsibility: Understanding The Impact on Gen Z Communication and Purchasing Decision in India
No full textCorporate Social Responsibility is an idea that a business adopts to act socially and environmentally positively towards the consumers. It is also seen as a strategic indicator that contributes to brand reputation. This qualitative study investigates the influence of Corporate Social Responsibility on Gen Z in India. Generation Z one of the most technologically advanced generations now. These digital humans have access to extensive information with just a click. However, it has been showcased that Generation Z whilst relying on worth-of-mouth, prefer to check ratings and reviews online rather than understanding companies’ values. This cuts off the relationship between humans and the companies and becomes a threat for firms that want to connect with the younger generation with their ideas and initiatives towards the environment. CSR not only creates a brand image but promotes consumer satisfaction.
The research takes a phenomenological approach, gathering primary data from six semi-structured interviews. The thematic analysis uncovered seven themes underpinning the findings of this study.
Broadly speaking, this study finds that Gen Z buying behavior is multifaceted and that whilst Gen Z desire to purchase products and services from companies that have high CSR standards, the actual buying decision is a factor of 1) Access to information and 2) Income levels and 3) Education levels
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