Naturally occurring potentially harmful elements in groundwater in makueni county, south‐eastern kenya : effects on drinking water quality and agriculture
- Gevera, Patrick, Cave, Mark, Dowling, Kim, Gikuma‐njuru, Peter, Mouri, Hassina
- Authors: Gevera, Patrick , Cave, Mark , Dowling, Kim , Gikuma‐njuru, Peter , Mouri, Hassina
- Date: 2020
- Type: Text , Journal article
- Relation: Geosciences (Switzerland) Vol. 10, no. 2 (2020), p.
- Full Text:
- Reviewed:
- Description: Makueni County is located in the semi‐arid south‐eastern Kenya region characterized by unreliable rainfall and limited surface water resources. This necessitates a high reliance on groundwater for domestic and agricultural use. In this paper, we report on the physico‐chemical characteristics of 20 drinking water sources (boreholes, shallow wells, streams, and tap water) collected during the dry season (November 2018), the geochemical processes controlling their composition, and their suitability for drinking water and irrigation. Of all the physico‐chemical parameters analysed, the concentrations of total dissolved solids, hardness, electrical conductivity, magnesium, calcium, chloride, and fluoride exceeded the permissible drinking water limits set by both the World Health Organization (WHO) and Kenya Bureau of Standards (KEBS) in up to 55% of the samples. The dominant ions reflect the high salinity in the water that ranged from very high to extreme in up to 50% of samples. The northern region shows the highest concentrations of the dominant parameters. The water type is predominantly Ca‐Mg‐HCO3 with a trend to Ca‐Mg‐Cl‐ SO4. Rock weathering and evaporation are suggested to be the primary controls of groundwater geochemical characteristics. High salinity and fluoride, which are associated with reported undesirable taste and gastrointestinal upsets, as well as cases of dental fluorosis are some of the effects of consuming groundwater in the region. These two parameters can be attributed to the weathering of biotite gneisses, granitoid gneisses, migmatites, and basaltic rocks that occur in the area. The high salinity and alkalinity of most of the samples analysed, renders the water unsuitable for irrigation in the study area. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- Authors: Gevera, Patrick , Cave, Mark , Dowling, Kim , Gikuma‐njuru, Peter , Mouri, Hassina
- Date: 2020
- Type: Text , Journal article
- Relation: Geosciences (Switzerland) Vol. 10, no. 2 (2020), p.
- Full Text:
- Reviewed:
- Description: Makueni County is located in the semi‐arid south‐eastern Kenya region characterized by unreliable rainfall and limited surface water resources. This necessitates a high reliance on groundwater for domestic and agricultural use. In this paper, we report on the physico‐chemical characteristics of 20 drinking water sources (boreholes, shallow wells, streams, and tap water) collected during the dry season (November 2018), the geochemical processes controlling their composition, and their suitability for drinking water and irrigation. Of all the physico‐chemical parameters analysed, the concentrations of total dissolved solids, hardness, electrical conductivity, magnesium, calcium, chloride, and fluoride exceeded the permissible drinking water limits set by both the World Health Organization (WHO) and Kenya Bureau of Standards (KEBS) in up to 55% of the samples. The dominant ions reflect the high salinity in the water that ranged from very high to extreme in up to 50% of samples. The northern region shows the highest concentrations of the dominant parameters. The water type is predominantly Ca‐Mg‐HCO3 with a trend to Ca‐Mg‐Cl‐ SO4. Rock weathering and evaporation are suggested to be the primary controls of groundwater geochemical characteristics. High salinity and fluoride, which are associated with reported undesirable taste and gastrointestinal upsets, as well as cases of dental fluorosis are some of the effects of consuming groundwater in the region. These two parameters can be attributed to the weathering of biotite gneisses, granitoid gneisses, migmatites, and basaltic rocks that occur in the area. The high salinity and alkalinity of most of the samples analysed, renders the water unsuitable for irrigation in the study area. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Extremality and stationarity of collections of sets : metric, slope and normal cone characterisations
- Bui, Hoa
- Authors: Bui, Hoa
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Variational analysis, a relatively new area of research in mathematics, has become one of the most powerful tools in nonsmooth optimisation and neighbouring areas. The extremal principle, a tool to substitute the conventional separation theorem in the general nonconvex environment, is a fundamental result in variational analysis. There have seen many attempts to generalise the conventional extremal principle in order to tackle certain optimisation models. Models involving collections of sets, initiated by the extremal principle, have proved their usefulness in analysis and optimisation, with non-intersection properties (or their absence) being at the core of many applications: recall the ubiquitous convex separation theorem, extremal principle, Dubovitskii Milyutin formalism and various transversality/regularity properties. We study elementary nonintersection properties of collections of sets, making the core of the conventional definitions of extremality and stationarity. In the setting of general Banach/Asplund spaces, we establish nonlinear primal (slope) and linear/nonlinear dual (generalised separation) characterisations of these non-intersection properties. We establish a series of consequences of our main results covering all known formulations of extremality/ stationarity and generalised separability properties. This research develops a universal theory, unifying all the current extensions of the extremal principle, providing new results and better understanding for the exquisite theory of variational analysis. This new study also results in direct solutions for many open questions and new future research directions in the fields of variational analysis and optimisation. Some new nonlinear characterisations of the conventional extremality/stationarity properties are obtained. For the first time, the intrinsic transversality property is characterised in primal space without involving normal cones. This characterisation brings a new perspective on intrinsic transversality. In the process, we thoroughly expose and classify all quantitative geometric and metric characterisations of transversality properties of collections of sets and regularity properties of set-valued mappings.
- Description: Doctor of Philosophy
- Authors: Bui, Hoa
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Variational analysis, a relatively new area of research in mathematics, has become one of the most powerful tools in nonsmooth optimisation and neighbouring areas. The extremal principle, a tool to substitute the conventional separation theorem in the general nonconvex environment, is a fundamental result in variational analysis. There have seen many attempts to generalise the conventional extremal principle in order to tackle certain optimisation models. Models involving collections of sets, initiated by the extremal principle, have proved their usefulness in analysis and optimisation, with non-intersection properties (or their absence) being at the core of many applications: recall the ubiquitous convex separation theorem, extremal principle, Dubovitskii Milyutin formalism and various transversality/regularity properties. We study elementary nonintersection properties of collections of sets, making the core of the conventional definitions of extremality and stationarity. In the setting of general Banach/Asplund spaces, we establish nonlinear primal (slope) and linear/nonlinear dual (generalised separation) characterisations of these non-intersection properties. We establish a series of consequences of our main results covering all known formulations of extremality/ stationarity and generalised separability properties. This research develops a universal theory, unifying all the current extensions of the extremal principle, providing new results and better understanding for the exquisite theory of variational analysis. This new study also results in direct solutions for many open questions and new future research directions in the fields of variational analysis and optimisation. Some new nonlinear characterisations of the conventional extremality/stationarity properties are obtained. For the first time, the intrinsic transversality property is characterised in primal space without involving normal cones. This characterisation brings a new perspective on intrinsic transversality. In the process, we thoroughly expose and classify all quantitative geometric and metric characterisations of transversality properties of collections of sets and regularity properties of set-valued mappings.
- Description: Doctor of Philosophy
Phenological studies in Australia: Potential application in historical and future climate analysis
- Keatley, Marie, Fletcher, Tim, Hudson, Irene, Ades, Peter
- Authors: Keatley, Marie , Fletcher, Tim , Hudson, Irene , Ades, Peter
- Date: 2002
- Type: Text , Journal article
- Relation: International Journal of Climatology Vol. 22, no. 14 (Nov 2002), p. 1769-1780
- Full Text:
- Reviewed:
- Description: Phenological observations of eucalypts (Myrtaceae) were undertaken in four Australian states (New South Wales, Queensland, Victoria, and Western Australia) from the late 1920s until the early 1980s, by the respective State Forest Commissions. Unfortunately, few records have survived. For Victoria, surviving records encompass 42 forest districts, covering from less than 2 years to 42 years, and approximately 50 species. This paper concentrates on the flowering of four competing species (Eucalyptus leucoxylon, E. microcarpa, E. polyanthemos, and E. tricarpa) over 23 years (1940-62) from Maryborough, Victoria, recorded on a monthly basis by one observer over the period. This study represents one of the first attempts to utilize Australian phenological data to detect responses to climate change. There were no significant trends (P = 0.05) over time in the mean flowering commencement date. Forward stepwise regression found a significant relationship between temperature and flowering commencement in two species (E. leucoxylon: R-2 = 0.42, P < 0.01; E. polyanthemos: R-2 = 0.47, P = 0.02). Rainfall also had a significant influence on flowering commencement in E. tricarpa (R-2 = 0.60, P < 0.01), E. leucoxylon (R-2 = 0.43, P = 0.02) and E. polyanthemos (R-2 = 0.24, P < 0.01). The combination of temperature and rainfall (with temperature exerting the greatest influence), however, was significant for all species and had the most explanatory power (ranging from R-2 = 0.74 to 0.85, P < 0.01). Overall, in response to predicted increases in temperature and summer rainfall, E. leucoxylon and E. tricarpa would commence flowering later. In E. polyanthemos and E. microcarpa, increased temperature and rainfall will result in an earlier onset of flowering. Copyright (C) 2002 Royal Meteorological Society.
- Description: 2003000171
- Authors: Keatley, Marie , Fletcher, Tim , Hudson, Irene , Ades, Peter
- Date: 2002
- Type: Text , Journal article
- Relation: International Journal of Climatology Vol. 22, no. 14 (Nov 2002), p. 1769-1780
- Full Text:
- Reviewed:
- Description: Phenological observations of eucalypts (Myrtaceae) were undertaken in four Australian states (New South Wales, Queensland, Victoria, and Western Australia) from the late 1920s until the early 1980s, by the respective State Forest Commissions. Unfortunately, few records have survived. For Victoria, surviving records encompass 42 forest districts, covering from less than 2 years to 42 years, and approximately 50 species. This paper concentrates on the flowering of four competing species (Eucalyptus leucoxylon, E. microcarpa, E. polyanthemos, and E. tricarpa) over 23 years (1940-62) from Maryborough, Victoria, recorded on a monthly basis by one observer over the period. This study represents one of the first attempts to utilize Australian phenological data to detect responses to climate change. There were no significant trends (P = 0.05) over time in the mean flowering commencement date. Forward stepwise regression found a significant relationship between temperature and flowering commencement in two species (E. leucoxylon: R-2 = 0.42, P < 0.01; E. polyanthemos: R-2 = 0.47, P = 0.02). Rainfall also had a significant influence on flowering commencement in E. tricarpa (R-2 = 0.60, P < 0.01), E. leucoxylon (R-2 = 0.43, P = 0.02) and E. polyanthemos (R-2 = 0.24, P < 0.01). The combination of temperature and rainfall (with temperature exerting the greatest influence), however, was significant for all species and had the most explanatory power (ranging from R-2 = 0.74 to 0.85, P < 0.01). Overall, in response to predicted increases in temperature and summer rainfall, E. leucoxylon and E. tricarpa would commence flowering later. In E. polyanthemos and E. microcarpa, increased temperature and rainfall will result in an earlier onset of flowering. Copyright (C) 2002 Royal Meteorological Society.
- Description: 2003000171
Interactions between a gall–inducing wasp Trichilogaster acaciaelongifoliae (Hymenoptera: Pteromalidae) and its host plant Acacia longifolia (Fabaceae)
- Authors: Islam, Md Rashedul
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sallow Wattle (Acacia longifolia subsp. longifolia) is a native Australian shrub which is an invasive weed in some parts of Australia, and internationally. A gall-forming wasp (Trichilogaster acaciaelongifoliae), also native to Australia, causes abnormal growth of tissues (galls) in Sallow Wattle. This wasp is used outside of Australia to control invasive populations of this plant species. However, in Australia, the wasp is not effective in managing the spread of Sallow Wattle. This study investigates various aspects of the relationship between the wasp and its host plant in Australian ecosystems to better understand the physiological and ecological processes involved. The study shows that this wasp is host-specific on Sallow Wattle. The feeding action of the larval wasps increase secondary plant compounds in gall tissue, which may assist the plant to defend itself chemically against other insects and microorganisms. The growth of the galls redirects resources which are otherwise used by the plant for growth and reproduction. A second insect species was found within the galls and was identified as Megastigmus sp. This second species is likely to be a parasitoid, killing the larvae of the gall-former and occupying the gall. The presence of Megastigmus sp. in Australian ecosystems may be a key factor affecting the ability of T. acaciaelongifoliae to control Sallow Wattle in its native range. The structure of galls formed by each type of gall-inducing insects is unique and the process of gall induction also varies across species. The present study has specifically examined the initiation and development of galls formed by T. acaciaelongifoliae on A. l. longifolia. Unlike other hymenopteran groups, which induce galls during oviposition, T. acaciaelongifoliae appears to form galls on A. l. longifolia via the larval feeding process. Three major stages of gall development were identified and described: induction of gall, growth and maturation of gall, and shrinking and desiccation of gall. These findings have significantly extended our current knowledge of gall induction and development by the hymenopteran group of insects. Total antioxidant capacity (TAC), total phenol (TP), and total anthocyanin (TA) were measured in galls formed by T. acaciaelongifoliae at different growth stages of galls and in other plant tissue samples of A. l. longifolia to understand the effect of gall formation on plant phytochemistry. The results indicated differences in the amounts of phytochemicals in tissue samples from galls of different growth stages of galls and between gall tissue samples and other plant samples of A. l. longifolia. The highest amount of total antioxidant capacity, total phenols and total anthocyanin were recorded in samples of early stages galls, whereas the minimum amounts of phytochemicals were in stems of A. l. longifolia. Amounts of antioxidant capacity, phenols and anthocyanin gradually declined as galls developed and larvae became less active in their feeding activity prior to pupation. It is assumed that the active feeding action of the larvae results in increased amounts of these chemicals in the early growth stages of the galls. The effect of galls formed by the wasp, T. acaciaelongifoliae on the growth and reproduction of A. l. longifolia was investigated in the native home range of both species, where the plant is invasive. Differences in the average number of phyllodes per sub-branch were found between galled and ungalled plants. Galls were also shown to affect the growth rate of branches. The number of galls correlated positively with twig mortality; and negatively with the number of seedpods per sub-branch. While galls formed by T. acaciaelongifoliae have impacts on the growth and reproduction of A. l. longifolia plants, the plant continues to invade Australian ecosystems. An experiment was conducted to investigate the host plant preference of T. acaciaelongifoliae. Ten different native host plant species (co-occurring with A. l. longifolia in the study locations) were tested in two set of experiments; a ‘free choice test’ and ‘no choice test’. The results showed that T. acaciaelongifoliae is highly host-specific on A. l. longifolia plants. Thus, it was concluded that the presence of other plant species does not explain the continued invasiveness of A. l. longifolia in Australia. A second insect species was found in the galls developed by T. acaciaelongifoliae on A. l. longifolia. The insect species has been identified as another hymenopteran from the genus Megastigmus. Since no T. acaciaelongifoliae emerged from the galls occupied by Megastigmus sp, it is proposed that Megastigmus sp. may feed upon T. acaciaelongifoliae larvae and kill them inside the galls. This might be a key factor affecting the performance of the wasp, T. acaciaelongifoliae in controlling A. l. longifolia in its native distribution. Parasitism rates of Megastigmus sp. should be investigated in future experiments.
- Description: Doctor of Philosophy
- Authors: Islam, Md Rashedul
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sallow Wattle (Acacia longifolia subsp. longifolia) is a native Australian shrub which is an invasive weed in some parts of Australia, and internationally. A gall-forming wasp (Trichilogaster acaciaelongifoliae), also native to Australia, causes abnormal growth of tissues (galls) in Sallow Wattle. This wasp is used outside of Australia to control invasive populations of this plant species. However, in Australia, the wasp is not effective in managing the spread of Sallow Wattle. This study investigates various aspects of the relationship between the wasp and its host plant in Australian ecosystems to better understand the physiological and ecological processes involved. The study shows that this wasp is host-specific on Sallow Wattle. The feeding action of the larval wasps increase secondary plant compounds in gall tissue, which may assist the plant to defend itself chemically against other insects and microorganisms. The growth of the galls redirects resources which are otherwise used by the plant for growth and reproduction. A second insect species was found within the galls and was identified as Megastigmus sp. This second species is likely to be a parasitoid, killing the larvae of the gall-former and occupying the gall. The presence of Megastigmus sp. in Australian ecosystems may be a key factor affecting the ability of T. acaciaelongifoliae to control Sallow Wattle in its native range. The structure of galls formed by each type of gall-inducing insects is unique and the process of gall induction also varies across species. The present study has specifically examined the initiation and development of galls formed by T. acaciaelongifoliae on A. l. longifolia. Unlike other hymenopteran groups, which induce galls during oviposition, T. acaciaelongifoliae appears to form galls on A. l. longifolia via the larval feeding process. Three major stages of gall development were identified and described: induction of gall, growth and maturation of gall, and shrinking and desiccation of gall. These findings have significantly extended our current knowledge of gall induction and development by the hymenopteran group of insects. Total antioxidant capacity (TAC), total phenol (TP), and total anthocyanin (TA) were measured in galls formed by T. acaciaelongifoliae at different growth stages of galls and in other plant tissue samples of A. l. longifolia to understand the effect of gall formation on plant phytochemistry. The results indicated differences in the amounts of phytochemicals in tissue samples from galls of different growth stages of galls and between gall tissue samples and other plant samples of A. l. longifolia. The highest amount of total antioxidant capacity, total phenols and total anthocyanin were recorded in samples of early stages galls, whereas the minimum amounts of phytochemicals were in stems of A. l. longifolia. Amounts of antioxidant capacity, phenols and anthocyanin gradually declined as galls developed and larvae became less active in their feeding activity prior to pupation. It is assumed that the active feeding action of the larvae results in increased amounts of these chemicals in the early growth stages of the galls. The effect of galls formed by the wasp, T. acaciaelongifoliae on the growth and reproduction of A. l. longifolia was investigated in the native home range of both species, where the plant is invasive. Differences in the average number of phyllodes per sub-branch were found between galled and ungalled plants. Galls were also shown to affect the growth rate of branches. The number of galls correlated positively with twig mortality; and negatively with the number of seedpods per sub-branch. While galls formed by T. acaciaelongifoliae have impacts on the growth and reproduction of A. l. longifolia plants, the plant continues to invade Australian ecosystems. An experiment was conducted to investigate the host plant preference of T. acaciaelongifoliae. Ten different native host plant species (co-occurring with A. l. longifolia in the study locations) were tested in two set of experiments; a ‘free choice test’ and ‘no choice test’. The results showed that T. acaciaelongifoliae is highly host-specific on A. l. longifolia plants. Thus, it was concluded that the presence of other plant species does not explain the continued invasiveness of A. l. longifolia in Australia. A second insect species was found in the galls developed by T. acaciaelongifoliae on A. l. longifolia. The insect species has been identified as another hymenopteran from the genus Megastigmus. Since no T. acaciaelongifoliae emerged from the galls occupied by Megastigmus sp, it is proposed that Megastigmus sp. may feed upon T. acaciaelongifoliae larvae and kill them inside the galls. This might be a key factor affecting the performance of the wasp, T. acaciaelongifoliae in controlling A. l. longifolia in its native distribution. Parasitism rates of Megastigmus sp. should be investigated in future experiments.
- Description: Doctor of Philosophy
Injury epidemiology among Australian female cricketers
- Authors: Perera, Nirmala
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cricket is a male-dominated sport; however, its popularity among females is increasing. Like other sports, participation in cricket poses the risk of injury to players. Injury problems for female cricketers are virtually unknown, as studies examining cricket injuries include almost exclusively male participants. In other sports, the types of injuries experienced by men and women are known to be different. Therefore, a clear understanding of the extent and types of injuries sustained by female cricket players is required, to underpin appropriately targeted injury prevention strategies. This thesis provides the first detailed epidemiological profile of cricket injuries sustained by women, by: 1. conducting a systematic review describing injuries in competitive team bat or stick sports in women, to enable cricket injuries to be viewed within the perspective of wider, but relevant, injury data, 2. evaluating existing data sources relating to hospital admissions from Victoria and Queensland and successful insurance claims across Australia, 3. examining the nature and incidence of cricket injuries in elite female players using Cricket Australia’s Athlete Management System, and 4. conducting a nationwide self-report survey of injuries during the 2014–15 season. This PhD research represents participants from different levels of play, across age groups and across Australia. The findings indicate that incidence of injuries for female cricketers were higher than expected based on previous findings in comparable sports, except when considered in relation to insurance claims. The cricket injury rate across hospital presentations, insurance claims, the AMS (Fair Play AMS 2016) and self-reported survey data, each of which represents different level of the sports injury pyramid, identified all-rounders and pace bowlers as having a higher incidence of injury than players in other positions. The highest frequency of reported injuries were in the head, hands, knees and ankles. The nature of the most common injuries were dislocations/sprains/strains, fractures, muscle injury, joint injury and gradual onset injuries. At the elite-level, lumber spine stress fractures accounted for a significant amount of time-loss from the sport. In this thesis, findings from the insurance claims, self-reported survey and AMS (Fair Play AMS 2016) data indicated that most injuries were of a low severity and were more likely to be treated outside of healthcare facilities such as hospitals. In summary, patterns of the most common injuries, in terms of anatomical location and nature of the injuries, were consistent throughout community-level players with some similarities to elite-level players. However, the injury mechanisms and risk factors may differ depending on the level of competition and player’s skill. Recommendations are that ongoing injury surveillance should be conducted at all levels of the sport, and surveillance methodology should be tailored to the specific setting, personnel and available resources. Therefore, before implementing an injury surveillance system at the community-level of the sport, more research is needed to fully understand what type of injury surveillance system might be feasible and suitable in this context.
- Description: Doctor of Philosophy
- Authors: Perera, Nirmala
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cricket is a male-dominated sport; however, its popularity among females is increasing. Like other sports, participation in cricket poses the risk of injury to players. Injury problems for female cricketers are virtually unknown, as studies examining cricket injuries include almost exclusively male participants. In other sports, the types of injuries experienced by men and women are known to be different. Therefore, a clear understanding of the extent and types of injuries sustained by female cricket players is required, to underpin appropriately targeted injury prevention strategies. This thesis provides the first detailed epidemiological profile of cricket injuries sustained by women, by: 1. conducting a systematic review describing injuries in competitive team bat or stick sports in women, to enable cricket injuries to be viewed within the perspective of wider, but relevant, injury data, 2. evaluating existing data sources relating to hospital admissions from Victoria and Queensland and successful insurance claims across Australia, 3. examining the nature and incidence of cricket injuries in elite female players using Cricket Australia’s Athlete Management System, and 4. conducting a nationwide self-report survey of injuries during the 2014–15 season. This PhD research represents participants from different levels of play, across age groups and across Australia. The findings indicate that incidence of injuries for female cricketers were higher than expected based on previous findings in comparable sports, except when considered in relation to insurance claims. The cricket injury rate across hospital presentations, insurance claims, the AMS (Fair Play AMS 2016) and self-reported survey data, each of which represents different level of the sports injury pyramid, identified all-rounders and pace bowlers as having a higher incidence of injury than players in other positions. The highest frequency of reported injuries were in the head, hands, knees and ankles. The nature of the most common injuries were dislocations/sprains/strains, fractures, muscle injury, joint injury and gradual onset injuries. At the elite-level, lumber spine stress fractures accounted for a significant amount of time-loss from the sport. In this thesis, findings from the insurance claims, self-reported survey and AMS (Fair Play AMS 2016) data indicated that most injuries were of a low severity and were more likely to be treated outside of healthcare facilities such as hospitals. In summary, patterns of the most common injuries, in terms of anatomical location and nature of the injuries, were consistent throughout community-level players with some similarities to elite-level players. However, the injury mechanisms and risk factors may differ depending on the level of competition and player’s skill. Recommendations are that ongoing injury surveillance should be conducted at all levels of the sport, and surveillance methodology should be tailored to the specific setting, personnel and available resources. Therefore, before implementing an injury surveillance system at the community-level of the sport, more research is needed to fully understand what type of injury surveillance system might be feasible and suitable in this context.
- Description: Doctor of Philosophy
Enhancing service quality and reliability in intelligent traffic system
- Authors: Chowdhury, Abdullahi
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Intelligent Traffic Systems (ITS) can manage on-road traffic efficiently based on real-time traffic conditions, reduce delay at the intersections, and maintain the safety of the road users. However, emergency vehicles still struggle to meet their targeted response time, and an ITS is vulnerable to various types of attacks, including cyberattacks. To address these issues, in this dissertation, we introduce three techniques that enhance the service quality and reliability of an ITS. First, an innovative Emergency Vehicle Priority System (EVPS) is presented to assist an Emergency Vehicle (EV) in attending the incident place faster. Our proposed EVPS determines the proper priority codes of EV based on the type of incidents. After priority code generation, EVPS selects the number of traffic signals needed to be turned green considering the impact on other vehicles gathered in the relevant adjacent cells. Second, for improving reliability, an Intrusion Detection System for traffic signals is proposed for the first time, which leverages traffic and signal characteristics such as the flow rate, vehicle speed, and signal phase time. Shannon’s entropy is used to calculate the uncertainty associated with the likelihood of particular evidence and Dempster-Shafer (DS) decision theory is used to fuse the evidential information. Finally, to improve the reliability of a future ITS, we introduce a model that assesses the trust level of four major On-Board Units (OBU) of a self-driving car along with Global Positioning System (GPS) data and safety messages. Both subjective logic (DS theory) and CertainLogic are used to develop the theoretical underpinning for estimating the trust value of a self-driving car by fusing the trust value of four OBU components, GPS data and safety messages. For evaluation and validation purposes, a popular and widely used traffic simulation package, namely Simulation of Urban Mobility (SUMO), is used to develop the simulation platform using a real map of Melbourne CBD. The relevant historical real data taken from the VicRoads website were used to inject the traffic flow and density in the simulation model. We evaluated the performance of our proposed techniques considering different traffic and signal characteristics such as occupancy rate, flow rate, phase time, and vehicle speed under many realistic scenarios. The simulation result shows the potential efficacy of our proposed techniques for all selected scenarios.
- Description: Doctor of Philosophy
- Authors: Chowdhury, Abdullahi
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Intelligent Traffic Systems (ITS) can manage on-road traffic efficiently based on real-time traffic conditions, reduce delay at the intersections, and maintain the safety of the road users. However, emergency vehicles still struggle to meet their targeted response time, and an ITS is vulnerable to various types of attacks, including cyberattacks. To address these issues, in this dissertation, we introduce three techniques that enhance the service quality and reliability of an ITS. First, an innovative Emergency Vehicle Priority System (EVPS) is presented to assist an Emergency Vehicle (EV) in attending the incident place faster. Our proposed EVPS determines the proper priority codes of EV based on the type of incidents. After priority code generation, EVPS selects the number of traffic signals needed to be turned green considering the impact on other vehicles gathered in the relevant adjacent cells. Second, for improving reliability, an Intrusion Detection System for traffic signals is proposed for the first time, which leverages traffic and signal characteristics such as the flow rate, vehicle speed, and signal phase time. Shannon’s entropy is used to calculate the uncertainty associated with the likelihood of particular evidence and Dempster-Shafer (DS) decision theory is used to fuse the evidential information. Finally, to improve the reliability of a future ITS, we introduce a model that assesses the trust level of four major On-Board Units (OBU) of a self-driving car along with Global Positioning System (GPS) data and safety messages. Both subjective logic (DS theory) and CertainLogic are used to develop the theoretical underpinning for estimating the trust value of a self-driving car by fusing the trust value of four OBU components, GPS data and safety messages. For evaluation and validation purposes, a popular and widely used traffic simulation package, namely Simulation of Urban Mobility (SUMO), is used to develop the simulation platform using a real map of Melbourne CBD. The relevant historical real data taken from the VicRoads website were used to inject the traffic flow and density in the simulation model. We evaluated the performance of our proposed techniques considering different traffic and signal characteristics such as occupancy rate, flow rate, phase time, and vehicle speed under many realistic scenarios. The simulation result shows the potential efficacy of our proposed techniques for all selected scenarios.
- Description: Doctor of Philosophy
Optimization based clustering and classification algorithms in analysis of microarray gene expression data sets
- Authors: Mardaneh, Karim
- Date: 2007
- Type: Text , Thesis , PhD
- Full Text:
- Description: Doctor of Philosophy
- Description: Bioinformatics and computational biology are relatively new areas that involve the use of different techniques including computer science, informatics, biochemistry, applied math and etc., to solve biological problems. In recent years the development of new molecular genetics technologies, such as DNA microarrays led to the simultaneous measurement of expression levels of thousands and even tens of thousands of genes. Microarray gene expression technology has facilitated the study of genomic structure and investigation of biological systems. Numerical output of this technology is shown as microarray gene expression data sets. These data sets contain a very large number of genes and a relatively small number of samples and their precise analysis requires a robust and suitable computer software. Due to this, only a few existing algorithms are applicable to them, so more efficient methods for solving clustering, gene selection and classification problems of gene expression data sets are required and those methods need to be computationally applicable and less expensive. The aim of this thesis is to develop new algorithms for solving clustering, gene selection and data classification problems on gene expression data sets. Clustering in gene expression data sets is a challenging problem. The increasing use of DNA microarray-based tumour gene expression profiles for cancer diagnosis requires more efficient methods to solve clustering problems of these profiles. Different algorithms for clustering of genes have been proposed, however few algorithms can be applied to the clustering of samples. k-means algorithm, among very few clustering algorithms is applicable to microarray gene expression data sets, however these are not efficient for solving clustering problems when the number of genes is thousands and this algorithm is very sensitive to the choice of a starting point. Additionally, when the number of clusters is relatively large, this algorithm gives local minima which can differ significantly from the global solution. Over the last several years different approaches have been proposed to improve global ii Abstract Abstract search properties of k-means algorithm. One of them is the global k-means algorithm, however this algorithm is not efficient when data are sparse. In this thesis we developed a new version of the global k-means algorithm, the modified global k-means algorithm which is effective for solving clustering problems in gene expression data sets. In a microarray gene expression data set, in many cases only a small fraction of genes are informative whereas most of them are non-informative and make noise. Therefore the development of gene selection algorithms that allow us to remove as many non-informative genes as possible is very important. In this thesis we developed a new overlapping gene selection algorithm. This algorithm is based on calculating overlaps of different genes. It considerably reduces the number of genes and is efficient in finding a subset of informative genes. Over the last decade different approaches have been proposed to solve supervised data classification problems in gene expression data sets. In this thesis we developed a new approach which is based on the so-called max-min separability and is compared with the other approaches. The max-min separability algorithm is an equivalent of piecewise linear separability. An incremental algorithm is presented to compute piecewise linear functions separating two sets. This algorithm is applied along with a special gene selection algorithm. In this thesis, all new algorithms have been tested on 10 publicly available gene expression data sets and our numerical results demonstrate the efficiency of the new algorithms that were developed in the framework of this research
- Authors: Mardaneh, Karim
- Date: 2007
- Type: Text , Thesis , PhD
- Full Text:
- Description: Doctor of Philosophy
- Description: Bioinformatics and computational biology are relatively new areas that involve the use of different techniques including computer science, informatics, biochemistry, applied math and etc., to solve biological problems. In recent years the development of new molecular genetics technologies, such as DNA microarrays led to the simultaneous measurement of expression levels of thousands and even tens of thousands of genes. Microarray gene expression technology has facilitated the study of genomic structure and investigation of biological systems. Numerical output of this technology is shown as microarray gene expression data sets. These data sets contain a very large number of genes and a relatively small number of samples and their precise analysis requires a robust and suitable computer software. Due to this, only a few existing algorithms are applicable to them, so more efficient methods for solving clustering, gene selection and classification problems of gene expression data sets are required and those methods need to be computationally applicable and less expensive. The aim of this thesis is to develop new algorithms for solving clustering, gene selection and data classification problems on gene expression data sets. Clustering in gene expression data sets is a challenging problem. The increasing use of DNA microarray-based tumour gene expression profiles for cancer diagnosis requires more efficient methods to solve clustering problems of these profiles. Different algorithms for clustering of genes have been proposed, however few algorithms can be applied to the clustering of samples. k-means algorithm, among very few clustering algorithms is applicable to microarray gene expression data sets, however these are not efficient for solving clustering problems when the number of genes is thousands and this algorithm is very sensitive to the choice of a starting point. Additionally, when the number of clusters is relatively large, this algorithm gives local minima which can differ significantly from the global solution. Over the last several years different approaches have been proposed to improve global ii Abstract Abstract search properties of k-means algorithm. One of them is the global k-means algorithm, however this algorithm is not efficient when data are sparse. In this thesis we developed a new version of the global k-means algorithm, the modified global k-means algorithm which is effective for solving clustering problems in gene expression data sets. In a microarray gene expression data set, in many cases only a small fraction of genes are informative whereas most of them are non-informative and make noise. Therefore the development of gene selection algorithms that allow us to remove as many non-informative genes as possible is very important. In this thesis we developed a new overlapping gene selection algorithm. This algorithm is based on calculating overlaps of different genes. It considerably reduces the number of genes and is efficient in finding a subset of informative genes. Over the last decade different approaches have been proposed to solve supervised data classification problems in gene expression data sets. In this thesis we developed a new approach which is based on the so-called max-min separability and is compared with the other approaches. The max-min separability algorithm is an equivalent of piecewise linear separability. An incremental algorithm is presented to compute piecewise linear functions separating two sets. This algorithm is applied along with a special gene selection algorithm. In this thesis, all new algorithms have been tested on 10 publicly available gene expression data sets and our numerical results demonstrate the efficiency of the new algorithms that were developed in the framework of this research
Self-reported worst injuries in women's Australian football identify lower limb injuries as a prevention priority
- Fortington, Lauren, Donaldson, Alex, Finch, Caroline
- Authors: Fortington, Lauren , Donaldson, Alex , Finch, Caroline
- Date: 2016
- Type: Text , Journal article
- Relation: BMJ Open Sport and Exercise Medicine Vol. 2, no. 1 (2016), p. e000112
- Relation: http://purl.org/au-research/grants/nhmrc/1058737
- Full Text:
- Reviewed:
- Description: BACKGROUND: Increasing participation by women in Australian football (AF) has made understanding their specific injury prevention needs a priority. In other sports, men and women have different injury profiles. This study aims to provide the first overview of self-reported injuries in women's AF. METHODS: Nationwide survey of women aged 17+ years who played in an AF competition was conducted following the 2014 playing season. The players' self-reported worst injury from the 2014 season is presented according to injury type, body part injured, treatment sought and games/training missed. RESULTS: Three-quarters of 553 respondents (n=431, 78%) reported at least 1 injury. Over half (n=235, 55%) of injuries were to the lower limb. Ankle ligament tears/sprains (n=50, 12% of all injuries) and knee ligament tears/sprains (n=45, 10%) were most frequent lower limb injuries reported. Two-thirds (65%) of all lower limb injuries led to at least 1 missed game. Of 111 (26% of all injuries) upper limb injuries reported, over half (n=57, 62%) were to the hand/fingers/thumb, including fractures (n=28, 6% of all injuries), ligament tears/sprains (n=18, 4%) and dislocations (n=11, 3%). Half of the upper limb injuries (51%) resulted in players missing matches/training. CONCLUSIONS: The most frequent self-reported worst injuries for women playing AF were joint damage to the ankle and knee. A prospective injury study is needed to confirm the causes and rate of these lower limb injuries to identify the most suitable prevention interventions.
- Authors: Fortington, Lauren , Donaldson, Alex , Finch, Caroline
- Date: 2016
- Type: Text , Journal article
- Relation: BMJ Open Sport and Exercise Medicine Vol. 2, no. 1 (2016), p. e000112
- Relation: http://purl.org/au-research/grants/nhmrc/1058737
- Full Text:
- Reviewed:
- Description: BACKGROUND: Increasing participation by women in Australian football (AF) has made understanding their specific injury prevention needs a priority. In other sports, men and women have different injury profiles. This study aims to provide the first overview of self-reported injuries in women's AF. METHODS: Nationwide survey of women aged 17+ years who played in an AF competition was conducted following the 2014 playing season. The players' self-reported worst injury from the 2014 season is presented according to injury type, body part injured, treatment sought and games/training missed. RESULTS: Three-quarters of 553 respondents (n=431, 78%) reported at least 1 injury. Over half (n=235, 55%) of injuries were to the lower limb. Ankle ligament tears/sprains (n=50, 12% of all injuries) and knee ligament tears/sprains (n=45, 10%) were most frequent lower limb injuries reported. Two-thirds (65%) of all lower limb injuries led to at least 1 missed game. Of 111 (26% of all injuries) upper limb injuries reported, over half (n=57, 62%) were to the hand/fingers/thumb, including fractures (n=28, 6% of all injuries), ligament tears/sprains (n=18, 4%) and dislocations (n=11, 3%). Half of the upper limb injuries (51%) resulted in players missing matches/training. CONCLUSIONS: The most frequent self-reported worst injuries for women playing AF were joint damage to the ankle and knee. A prospective injury study is needed to confirm the causes and rate of these lower limb injuries to identify the most suitable prevention interventions.
Static code analysis of data-driven applications through common lingua and the Semantic Web technologies
- Authors: Ureche, Oana
- Date: 2015
- Type: Text , Thesis , PhD
- Full Text:
- Description: Web applications have become increasingly popular due to their potential for businesses' high revenue gain through global reach. Along with these opportunities, also come challenges in terms of Web application security. The increased rise in the number of datadriven applications has also seen an increased rise in their systematic attacks. Cyberattacks exploit Web application vulnerabilities. Attack trends show a major increase in Web application vulnerabilities caused by improper implementation of information-flow control methods and they account for more than 50% of all Web application vulnerabilities found in the year 2013. Static code analysis using methods of information-flow control is a widely acknowledged technique to secure Web applications. Whilst this technique has been found to be both very effective and efficient in finding Web application vulnerabilities, specific tools are highly dependent on the programming language. This thesis leverages Semantic Web technologies in order to offer a common language through source code represented using the Resource Description Framework format, whereby reasoning can be applied to securely test Web applications. In this thesis, we present a framework that extracts source code facts from various programming languages at a variable-level of granularity using Abstract Syntax Trees (ASTs) generated using language grammars and the ANTLR parser generator. The methodology for detecting Web application vulnerabilities implements three phases: entry points identification, tracing information-flow and vulnerability detection using the Jena framework inference mechanism and rules describing patterns of source code. The approach discussed in this thesis is found to be effective and practical in finding Web application vulnerabilities with the limitation that it can only detect patterns that are used as training data or very similar patterns. False positives are caused by limitations of the language grammar, but they do not affect the accuracy of the security vulnerability detection method in identifying the correct Web application vulnerability.
- Description: Doctor of Philosophy
- Authors: Ureche, Oana
- Date: 2015
- Type: Text , Thesis , PhD
- Full Text:
- Description: Web applications have become increasingly popular due to their potential for businesses' high revenue gain through global reach. Along with these opportunities, also come challenges in terms of Web application security. The increased rise in the number of datadriven applications has also seen an increased rise in their systematic attacks. Cyberattacks exploit Web application vulnerabilities. Attack trends show a major increase in Web application vulnerabilities caused by improper implementation of information-flow control methods and they account for more than 50% of all Web application vulnerabilities found in the year 2013. Static code analysis using methods of information-flow control is a widely acknowledged technique to secure Web applications. Whilst this technique has been found to be both very effective and efficient in finding Web application vulnerabilities, specific tools are highly dependent on the programming language. This thesis leverages Semantic Web technologies in order to offer a common language through source code represented using the Resource Description Framework format, whereby reasoning can be applied to securely test Web applications. In this thesis, we present a framework that extracts source code facts from various programming languages at a variable-level of granularity using Abstract Syntax Trees (ASTs) generated using language grammars and the ANTLR parser generator. The methodology for detecting Web application vulnerabilities implements three phases: entry points identification, tracing information-flow and vulnerability detection using the Jena framework inference mechanism and rules describing patterns of source code. The approach discussed in this thesis is found to be effective and practical in finding Web application vulnerabilities with the limitation that it can only detect patterns that are used as training data or very similar patterns. False positives are caused by limitations of the language grammar, but they do not affect the accuracy of the security vulnerability detection method in identifying the correct Web application vulnerability.
- Description: Doctor of Philosophy
Enhancing the implementation of injury prevention exercise programs in professional soccer
- Authors: O’Brien, James
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: Recently, injury prevention exercise programs (IPEPs) for soccer have received considerable attention and their efficacy has been demonstrated in large-scale trials. However, the ultimate impact of IPEPs will depend not only on their efficacy under controlled conditions, but also on the extent to which they are successfully implemented under real-world conditions. Despite increasing recognition of the challenges involved in successfully implementing IPEPs, there is a paucity of research addressing these challenges. The first aim of this thesis was to systematically review published IPEP trial reports, from an implementation perspective, in both soccer and other team ball sports. To achieve this, an established health-promotion framework, called the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) framework, was employed. The subsequent phases of the thesis aimed to identify IPEP implementation barriers and facilitators in the specific context of professional soccer. Two cross-sectional surveys explored the perceptions of IPEP users in professional teams and a prospective observational study assessed IPEP use, over one playing season, in a professional youth soccer academy. Evaluation of the published literature against the RE-AIM framework revealed major gaps in the reporting of specific IPEP implementation aspects, particularly relating to program adoption and maintenance. In professional soccer teams, multiple IPEP implementation barriers and facilitators were identified. These factors related either to the content and nature of the IPEPs themselves (e.g. variation, progression and soccer-specificity), or the delivery and support of programs (e.g. communication and team work) at different levels of the professional soccer ecology. In summary, there are major gaps in the reporting of implementation aspects in team ball sport trials. To enhance the implementation of IPEPs in professional soccer settings, the content and delivery of programs require significant tailoring to the specific implementation context.
- Description: Doctor of Philosophy
- Authors: O’Brien, James
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: Recently, injury prevention exercise programs (IPEPs) for soccer have received considerable attention and their efficacy has been demonstrated in large-scale trials. However, the ultimate impact of IPEPs will depend not only on their efficacy under controlled conditions, but also on the extent to which they are successfully implemented under real-world conditions. Despite increasing recognition of the challenges involved in successfully implementing IPEPs, there is a paucity of research addressing these challenges. The first aim of this thesis was to systematically review published IPEP trial reports, from an implementation perspective, in both soccer and other team ball sports. To achieve this, an established health-promotion framework, called the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) framework, was employed. The subsequent phases of the thesis aimed to identify IPEP implementation barriers and facilitators in the specific context of professional soccer. Two cross-sectional surveys explored the perceptions of IPEP users in professional teams and a prospective observational study assessed IPEP use, over one playing season, in a professional youth soccer academy. Evaluation of the published literature against the RE-AIM framework revealed major gaps in the reporting of specific IPEP implementation aspects, particularly relating to program adoption and maintenance. In professional soccer teams, multiple IPEP implementation barriers and facilitators were identified. These factors related either to the content and nature of the IPEPs themselves (e.g. variation, progression and soccer-specificity), or the delivery and support of programs (e.g. communication and team work) at different levels of the professional soccer ecology. In summary, there are major gaps in the reporting of implementation aspects in team ball sport trials. To enhance the implementation of IPEPs in professional soccer settings, the content and delivery of programs require significant tailoring to the specific implementation context.
- Description: Doctor of Philosophy
The association of circular RNAs with hypertension
- Authors: Woods, Bradley
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis contains six chapters in total with chapter 1 being a literature overview and chapter 2 being a summary of material and methods. The three results chapters contain all my own work unless stated otherwise and lastly chapter 6 is discussion and conclusions linking together the work undertaken in this thesis.
- Description: Doctor of Philosophy
- Authors: Woods, Bradley
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis contains six chapters in total with chapter 1 being a literature overview and chapter 2 being a summary of material and methods. The three results chapters contain all my own work unless stated otherwise and lastly chapter 6 is discussion and conclusions linking together the work undertaken in this thesis.
- Description: Doctor of Philosophy
Changes in muscle activation following balance and technique training and a season of Australian football
- Donnelly, Cyril, Elliott, Bruce, Doyle, Tim, Finch, Caroline, Dempsey, Alasdair, Lloyd, David
- Authors: Donnelly, Cyril , Elliott, Bruce , Doyle, Tim , Finch, Caroline , Dempsey, Alasdair , Lloyd, David
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 18, no. 3 (2014), p.348-352
- Relation: http://purl.org/au-research/grants/nhmrc/565900
- Full Text:
- Reviewed:
- Description: Objectives: Determine if balance and technique training implemented adjunct to 1001 male Australian football players' training influenced the activation/strength of the muscles crossing the knee during pre-planned and unplanned sidestepping. Design: Randomized Control Trial. Methods: Each Australian football player participated in either 28 weeks of balance and technique training or 'sham' training. Twenty-eight Australian football players (balance and technique training, n = 12; 'sham' training, n = 16) completed biomechanical testing pre-to-post training. Peak knee moments and directed co-contraction ratios in three degrees of freedom, as well as total muscle activation were calculated during pre-planned and unplanned sidestepping. Results: No significant differences in muscle activation/strength were observed between the 'sham' training and balance and technique training groups. Following a season of Australian football, knee extensor (p = 0.023) and semimembranosus (p = 0.006) muscle activation increased during both pre-planned sidestepping and unplanned sidestepping. Following a season of Australian football, total muscle activation was 30% lower and peak valgus knee moments 80% greater (p = 0.022) during unplanned sidestepping when compared with pre-planned sidestepping. Conclusions: When implemented in a community level training environment, balance and technique training was not effective in changing the activation of the muscles crossing the knee during sidestepping. Following a season of Australian football, players are better able to support both frontal and sagittal plane knee moments. When compared to pre-planned sidestepping, Australian football players may be at increased risk of anterior cruciate ligament injury during unplanned sidestepping in the latter half of an Australian football season.
- Authors: Donnelly, Cyril , Elliott, Bruce , Doyle, Tim , Finch, Caroline , Dempsey, Alasdair , Lloyd, David
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 18, no. 3 (2014), p.348-352
- Relation: http://purl.org/au-research/grants/nhmrc/565900
- Full Text:
- Reviewed:
- Description: Objectives: Determine if balance and technique training implemented adjunct to 1001 male Australian football players' training influenced the activation/strength of the muscles crossing the knee during pre-planned and unplanned sidestepping. Design: Randomized Control Trial. Methods: Each Australian football player participated in either 28 weeks of balance and technique training or 'sham' training. Twenty-eight Australian football players (balance and technique training, n = 12; 'sham' training, n = 16) completed biomechanical testing pre-to-post training. Peak knee moments and directed co-contraction ratios in three degrees of freedom, as well as total muscle activation were calculated during pre-planned and unplanned sidestepping. Results: No significant differences in muscle activation/strength were observed between the 'sham' training and balance and technique training groups. Following a season of Australian football, knee extensor (p = 0.023) and semimembranosus (p = 0.006) muscle activation increased during both pre-planned sidestepping and unplanned sidestepping. Following a season of Australian football, total muscle activation was 30% lower and peak valgus knee moments 80% greater (p = 0.022) during unplanned sidestepping when compared with pre-planned sidestepping. Conclusions: When implemented in a community level training environment, balance and technique training was not effective in changing the activation of the muscles crossing the knee during sidestepping. Following a season of Australian football, players are better able to support both frontal and sagittal plane knee moments. When compared to pre-planned sidestepping, Australian football players may be at increased risk of anterior cruciate ligament injury during unplanned sidestepping in the latter half of an Australian football season.
Optimality conditions for nonsmooth optimization problems via generalised derivatives
- Authors: Hassani, Sara
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: Aquatic plants are integral components of freshwater ecosystems and provide essential ecosystem services. However, when invasive species establish in new aquatic environments, there are few natural checks and balances to inhibit their growth and spread. Overabundant aquatic vegetation can harm aquatic systems if left unchecked and negatively impact on agricultural productivity, social amenity and biodiversity values. Prevention and early intervention are recognised as the most cost effective means to manage invasive species that pose a biosecurity risk. This thesis contributes to the development of effective management strategies for one of the world’s most invasive aquatic plant species, known as alligator weed (Alternanthera philoxeroides (Mart.) Griseb.). It focusses on developing management strategies in an early stage of invasion, in order to achieve extirpation of this species from catchments and waterways. Developing effective detection and surveillance strategies are required for invasive aquatic plants, as a key impediment to achieving extirpation is the ability to detect infestations, so that control strategies can be enacted. This thesis investigates the effectiveness of aerial surveillance for detection of alligator weed at different spatial scales, using high altitude aerial imagery (orthophotos) and unmanned aerial vehicle (UAV) technology. An examination of the growth rate of alligator weed in Victoria, Australia, over a five year period, demonstrates the effective use of orthophotos to detect and monitor large infestations of aquatic alligator weed. The efficacy of unmanned aerial vehicle technology, including the use of automated algorithms, to detect patches of alligator weed growing in waterways is evaluated against current detection techniques. Effective management of invasive aquatic plants targeted for extirpation requires the coupling of effective detection and control efforts to prevent reproduction. To date, development of control strategies for aquatic alligator weed has been limited to evaluating the efficacy of short-term control at a local scale without regard to the effects of management strategies on dispersal of propagules throughout catchments. This thesis determines that viable alligator weed stem fragments are produced following herbicide application, which comprises extirpation efforts. This thesis has gone further than current practice in that it has evaluated the efficacy of current and novel control techniques, in both laboratory and field trials and has developed methods to manage viable fragment production post-herbicide application, to limit dispersal throughout catchments. In this respect, the application of the herbicides glyphosate, metsulfuron-methyl and imazapyr, and their effectiveness when incorporating surfactant systems and plant growth regulators, have been evaluated in field and laboratory studies to optimise control techniques for aquatic alligator weed. Results have shown that our approaches, when used in an early stage of invasion, are capable of eliminating patches of alligator weed in two to three years. Integral to the research is an experiment to determine the effect of herbicide treatments on the production of alligator weed stem fragments and their subsequent viability. Further investigation to determine the usefulness of commercially available plant growth regulators (PGRs) to reduce the number of viable propagules produced by alligator weed post-herbicide application was found to be ineffective. This thesis also evaluates the impact of herbicides and surfactant systems, on all key alligator weed response metrics in aquatic environments including; above ground biomass, below ground biomass and viable stem fragmentation. No previous studies have looked simultaneously at these three important measures for determining the efficacy of a particular control regime, and we have determined that this is essential for effective management of aquatic alligator weed in an early stage of invasion. The thesis has underscored the notion that development of more effective management strategies, based upon experimental trials, will result in an increased likelihood of eradicating invasive aquatic plants that pose a biosecurity risk, and thus move toward the mitigation of the threat that high-risk species pose to aquatic ecosystems. PLEASE NOTE: Portions of the full text have been removed due to copyright restrictions.
- Description: Doctor of Philosophy
- Authors: Hassani, Sara
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: Aquatic plants are integral components of freshwater ecosystems and provide essential ecosystem services. However, when invasive species establish in new aquatic environments, there are few natural checks and balances to inhibit their growth and spread. Overabundant aquatic vegetation can harm aquatic systems if left unchecked and negatively impact on agricultural productivity, social amenity and biodiversity values. Prevention and early intervention are recognised as the most cost effective means to manage invasive species that pose a biosecurity risk. This thesis contributes to the development of effective management strategies for one of the world’s most invasive aquatic plant species, known as alligator weed (Alternanthera philoxeroides (Mart.) Griseb.). It focusses on developing management strategies in an early stage of invasion, in order to achieve extirpation of this species from catchments and waterways. Developing effective detection and surveillance strategies are required for invasive aquatic plants, as a key impediment to achieving extirpation is the ability to detect infestations, so that control strategies can be enacted. This thesis investigates the effectiveness of aerial surveillance for detection of alligator weed at different spatial scales, using high altitude aerial imagery (orthophotos) and unmanned aerial vehicle (UAV) technology. An examination of the growth rate of alligator weed in Victoria, Australia, over a five year period, demonstrates the effective use of orthophotos to detect and monitor large infestations of aquatic alligator weed. The efficacy of unmanned aerial vehicle technology, including the use of automated algorithms, to detect patches of alligator weed growing in waterways is evaluated against current detection techniques. Effective management of invasive aquatic plants targeted for extirpation requires the coupling of effective detection and control efforts to prevent reproduction. To date, development of control strategies for aquatic alligator weed has been limited to evaluating the efficacy of short-term control at a local scale without regard to the effects of management strategies on dispersal of propagules throughout catchments. This thesis determines that viable alligator weed stem fragments are produced following herbicide application, which comprises extirpation efforts. This thesis has gone further than current practice in that it has evaluated the efficacy of current and novel control techniques, in both laboratory and field trials and has developed methods to manage viable fragment production post-herbicide application, to limit dispersal throughout catchments. In this respect, the application of the herbicides glyphosate, metsulfuron-methyl and imazapyr, and their effectiveness when incorporating surfactant systems and plant growth regulators, have been evaluated in field and laboratory studies to optimise control techniques for aquatic alligator weed. Results have shown that our approaches, when used in an early stage of invasion, are capable of eliminating patches of alligator weed in two to three years. Integral to the research is an experiment to determine the effect of herbicide treatments on the production of alligator weed stem fragments and their subsequent viability. Further investigation to determine the usefulness of commercially available plant growth regulators (PGRs) to reduce the number of viable propagules produced by alligator weed post-herbicide application was found to be ineffective. This thesis also evaluates the impact of herbicides and surfactant systems, on all key alligator weed response metrics in aquatic environments including; above ground biomass, below ground biomass and viable stem fragmentation. No previous studies have looked simultaneously at these three important measures for determining the efficacy of a particular control regime, and we have determined that this is essential for effective management of aquatic alligator weed in an early stage of invasion. The thesis has underscored the notion that development of more effective management strategies, based upon experimental trials, will result in an increased likelihood of eradicating invasive aquatic plants that pose a biosecurity risk, and thus move toward the mitigation of the threat that high-risk species pose to aquatic ecosystems. PLEASE NOTE: Portions of the full text have been removed due to copyright restrictions.
- Description: Doctor of Philosophy
Progressive rebels of Boy's Own Adventure? The 1935 Australian Cricket tour of India; breaking down social and racial barriers
- Authors: Ponsford, Megan
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: In October 1935, a touring party embarked on the inaugural tour of India by an Australian cricket team. To a great, and somewhat stereotypical, extent popular representations of IndianeAustralian relations are viewed through the lens of cricket – the national game in both countries. This dissertation about a significant, yet overlooked, chapter in sporting history examines the Australian cricketers’ response to the social, racial and political hierarchies of lateecolonial India. The experience of the touring party encouraged a reeimagining of ideological perspectives and this thesis identifies a uniquely Australian subjectivity to the British colonisation of India. The tour between the colony (India) and the dominion (Australia) can be interpreted as an antie imperial gesture. Both countries were attempting to forge relationships that would be independent from Britain. The role of cricket, itself experiencing a renaissance during the 1930s as it transformed from a largely amateur pursuit to an increasingly professional occupation is interrogated. As part of this transformation international cricket positioned itself as an increasingly politicised global entity within the broader turbulence of the firstehalf of the twentieth century. All those involved in the tour are now dead. However a close historical analysis of previously lost, highly personalised, primary material (letters, manuscripts, photographs and cricket ephemera) enables an interpretation of the players’ experience. This thesis argues that sporting events can be interpreted as cultural ciphers yet scholars and the wider sportsewriting community have neglected the historical significance of the 1935/36 tour. The unofficial status of the tour and its highly professional emphasis alienated it from the amateur ideals of Australian cricket. This transnational, multiedisciplinary approach addresses a lacunae in the professional trajectory of cricket. It also provides a new understanding and historical counter narrative of idetwentieth century IndianeAustralian sporting history and cultural exchange.
- Description: Doctor of Philosophy
- Authors: Ponsford, Megan
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: In October 1935, a touring party embarked on the inaugural tour of India by an Australian cricket team. To a great, and somewhat stereotypical, extent popular representations of IndianeAustralian relations are viewed through the lens of cricket – the national game in both countries. This dissertation about a significant, yet overlooked, chapter in sporting history examines the Australian cricketers’ response to the social, racial and political hierarchies of lateecolonial India. The experience of the touring party encouraged a reeimagining of ideological perspectives and this thesis identifies a uniquely Australian subjectivity to the British colonisation of India. The tour between the colony (India) and the dominion (Australia) can be interpreted as an antie imperial gesture. Both countries were attempting to forge relationships that would be independent from Britain. The role of cricket, itself experiencing a renaissance during the 1930s as it transformed from a largely amateur pursuit to an increasingly professional occupation is interrogated. As part of this transformation international cricket positioned itself as an increasingly politicised global entity within the broader turbulence of the firstehalf of the twentieth century. All those involved in the tour are now dead. However a close historical analysis of previously lost, highly personalised, primary material (letters, manuscripts, photographs and cricket ephemera) enables an interpretation of the players’ experience. This thesis argues that sporting events can be interpreted as cultural ciphers yet scholars and the wider sportsewriting community have neglected the historical significance of the 1935/36 tour. The unofficial status of the tour and its highly professional emphasis alienated it from the amateur ideals of Australian cricket. This transnational, multiedisciplinary approach addresses a lacunae in the professional trajectory of cricket. It also provides a new understanding and historical counter narrative of idetwentieth century IndianeAustralian sporting history and cultural exchange.
- Description: Doctor of Philosophy
Performance evaluation of rockburst prediction based on PSO-SVM, HHO-SVM, and MFO-SVM hybrid models
- Zhou, Jian, Yang, Peixi, Peng, Pingan, Khandelwal, Manoj, Qiu, Yingui
- Authors: Zhou, Jian , Yang, Peixi , Peng, Pingan , Khandelwal, Manoj , Qiu, Yingui
- Date: 2023
- Type: Text , Journal article
- Relation: Mining, Metallurgy and Exploration Vol. 40, no. 2 (2023), p. 617-635
- Full Text:
- Reviewed:
- Description: Rockburst prediction is crucial in deep hard rock mines and tunnels to make safer working conditions. Due to the complex interaction of many factors involved in rockburst prediction, such as multi-variable and multi-interference factors, three hybrid support vector machine (SVM) models optimized by particle swarm optimization (PSO), Harris hawk optimization (HHO), and moth flame optimization (MFO) are proposed to predict rockburst hazard level (RHL). The RHL is determined according to four kinds of microseismic characteristic parameters including angular frequency ratio, total energy, apparent stress, and convexity radius. Then, six types of microseismic characteristic parameters are taken as input variables in 343 sets of data, including angular frequency ratio and total energy, etc. And the RHL is taken as the output target of rockburst prediction. The classification performance of PSO-SVM, HHO-SVM, and MFO-SVM hybrid models is evaluated by accuracy (ACC), precision (PRE), and kappa coefficient. Findings reveal that the MFO-SVM model performs best in terms of accuracy, with ACC, PRE, and kappa coefficients reaching 0.9559, 0.9063, and 0.9094 respectively, while PSO-SVM and HHO-SVM have similar performances. However, the PSO-SVM, HHO-SVM, and MFO-SVM all perform better than the unoptimized SVM model. This confirms that the three optimization algorithms significantly enhance the rockburst prediction capacity of the SVM model to help mine practitioners apply machine learning methods to rockburst prediction problems appropriately. © 2023, Society for Mining, Metallurgy & Exploration Inc.
- Authors: Zhou, Jian , Yang, Peixi , Peng, Pingan , Khandelwal, Manoj , Qiu, Yingui
- Date: 2023
- Type: Text , Journal article
- Relation: Mining, Metallurgy and Exploration Vol. 40, no. 2 (2023), p. 617-635
- Full Text:
- Reviewed:
- Description: Rockburst prediction is crucial in deep hard rock mines and tunnels to make safer working conditions. Due to the complex interaction of many factors involved in rockburst prediction, such as multi-variable and multi-interference factors, three hybrid support vector machine (SVM) models optimized by particle swarm optimization (PSO), Harris hawk optimization (HHO), and moth flame optimization (MFO) are proposed to predict rockburst hazard level (RHL). The RHL is determined according to four kinds of microseismic characteristic parameters including angular frequency ratio, total energy, apparent stress, and convexity radius. Then, six types of microseismic characteristic parameters are taken as input variables in 343 sets of data, including angular frequency ratio and total energy, etc. And the RHL is taken as the output target of rockburst prediction. The classification performance of PSO-SVM, HHO-SVM, and MFO-SVM hybrid models is evaluated by accuracy (ACC), precision (PRE), and kappa coefficient. Findings reveal that the MFO-SVM model performs best in terms of accuracy, with ACC, PRE, and kappa coefficients reaching 0.9559, 0.9063, and 0.9094 respectively, while PSO-SVM and HHO-SVM have similar performances. However, the PSO-SVM, HHO-SVM, and MFO-SVM all perform better than the unoptimized SVM model. This confirms that the three optimization algorithms significantly enhance the rockburst prediction capacity of the SVM model to help mine practitioners apply machine learning methods to rockburst prediction problems appropriately. © 2023, Society for Mining, Metallurgy & Exploration Inc.
Exploring the effects of perioperative and preoperative exercise therapy for prostate, colorectal and breast cancer patients
- Authors: Hennessy, Declan
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cancer is a prevalent disease with significant morbidity and mortality rates. Exercise interventions implemented before, during, or after cancer-based surgeries have shown promising benefits in improving fitness, postoperative complications, and quality of life. This thesis comprises three original research chapters aimed at investigating the effect of perioperative and preoperative 'prehabilitation' exercise in breast, colorectal, and prostate cancer patients. The first study focused on exploring exercise therapy interventions and their impact on cardio-respiratory fitness and 30-day postoperative outcomes in colorectal cancer patients. The systematic review and meta-analysis (N= 411 intervention and N= 368 control) revealed a small but significant improvement in cardio-respiratory fitness (SMD = 0.18; 95% CI = 0.03, 0.32; p < 0.05) with exercise interventions, although no significant impact on 30-day postoperative outcomes was observed. In the second study, various exercise types, including aerobic, resistance, flexibility, and mind-body exercises (alone or in combination), were compared in terms of their effect on cardio-respiratory fitness and 30-day postoperative outcomes in colorectal cancer patients (N= 411 intervention and N= 368 control). The network meta-analysis findings indicated that engaging in aerobic exercise alone (SMD = 0.30) or a combination of aerobic, resistance, and flexibility exercises (SMD = 0.57) yielded the most significant improvements in cardio-respiratory fitness. The final study examined the efficacy of pre-surgical aerobic exercise (prehabilitation) therapy in relation to post-operative cardio-respiratory fitness, quality of life, and 30-day postoperative outcomes in the Grampians Region of Victoria. The prehabilitation (PREHAB) group included a supervised aerobic based program which would see patients exercise every two/three days for a minimum of 2 weeks. A total of 11 PREHAB and 9 usual care (UCARE) patients were enrolled and analysed. The study showed that a prehabilitation exercise program resulted in small clinical improvements in some markers of cardio-respiratory fitness (+1.5% and +1.2% for absolute and relative V̇O2peak, respectively) and is safe and feasible. However, no significant improvements were observed in quality of life and 30-day postoperative outcomes. While the overall findings demonstrate some positive effects of perioperative and specifically prehabilitation exercise, it is important to consider the magnitude of these effects and any specific factors contributing to their success, if applicable. Further research is needed to fully understand the potential benefits and limitations of exercise before, during and after surgery in this patient population.
- Description: Doctor of Philosophy
- Authors: Hennessy, Declan
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cancer is a prevalent disease with significant morbidity and mortality rates. Exercise interventions implemented before, during, or after cancer-based surgeries have shown promising benefits in improving fitness, postoperative complications, and quality of life. This thesis comprises three original research chapters aimed at investigating the effect of perioperative and preoperative 'prehabilitation' exercise in breast, colorectal, and prostate cancer patients. The first study focused on exploring exercise therapy interventions and their impact on cardio-respiratory fitness and 30-day postoperative outcomes in colorectal cancer patients. The systematic review and meta-analysis (N= 411 intervention and N= 368 control) revealed a small but significant improvement in cardio-respiratory fitness (SMD = 0.18; 95% CI = 0.03, 0.32; p < 0.05) with exercise interventions, although no significant impact on 30-day postoperative outcomes was observed. In the second study, various exercise types, including aerobic, resistance, flexibility, and mind-body exercises (alone or in combination), were compared in terms of their effect on cardio-respiratory fitness and 30-day postoperative outcomes in colorectal cancer patients (N= 411 intervention and N= 368 control). The network meta-analysis findings indicated that engaging in aerobic exercise alone (SMD = 0.30) or a combination of aerobic, resistance, and flexibility exercises (SMD = 0.57) yielded the most significant improvements in cardio-respiratory fitness. The final study examined the efficacy of pre-surgical aerobic exercise (prehabilitation) therapy in relation to post-operative cardio-respiratory fitness, quality of life, and 30-day postoperative outcomes in the Grampians Region of Victoria. The prehabilitation (PREHAB) group included a supervised aerobic based program which would see patients exercise every two/three days for a minimum of 2 weeks. A total of 11 PREHAB and 9 usual care (UCARE) patients were enrolled and analysed. The study showed that a prehabilitation exercise program resulted in small clinical improvements in some markers of cardio-respiratory fitness (+1.5% and +1.2% for absolute and relative V̇O2peak, respectively) and is safe and feasible. However, no significant improvements were observed in quality of life and 30-day postoperative outcomes. While the overall findings demonstrate some positive effects of perioperative and specifically prehabilitation exercise, it is important to consider the magnitude of these effects and any specific factors contributing to their success, if applicable. Further research is needed to fully understand the potential benefits and limitations of exercise before, during and after surgery in this patient population.
- Description: Doctor of Philosophy
Breaking the safety barrier : engineering new paradigms in safety design
- Authors: Culvenor, John
- Date: 1997
- Type: Text , Thesis , PhD
- Full Text:
- Description: Occupational health and safety legislation in Australia and internationally is based on the safe place concept and the hierarchy of control. A safe place is best achieved at the design stage and consequently the education of engineers in safety has been a priority. There have been notable efforts at the integration of safety with engineering studies, and this should be an ongoing objective, however extensive integration is likely to be difficult at least in the short term. The challenge was to develop a supplemental, innovative way to improve the ability of engineers to develop safe place solutions. The hypothesis was that training in creative thinking would achieve this aim. The hierarchy of control methodology shares a strong relationship with creative thinking. Safe place thinking challenges assumptions in the same way that creative thinking seeks to escape dominant paradigms. For this reason creative thinking seems a natural aid to the safe place approach. This study tested the effect on safety design of a creative thinking program; de Bono’s six thinking hats method. Given a recognition that groups other than engineers impact on workplace design, a range of subjects were included; engineering students, technology students, industry safety advisers, and government safety advisers. In response to safety case studies, subjects were required to generate solutions and to prioritize potential solutions. Subjects worked on a range of problems, some individually and some in teams of three. Results show that training in creative thinking improved the generation of solutions to safety problems. As the number of solutions increased, the average quality of ideas was maintained, therefore the increased number of solutions was accompanied by a similar increase in good quality safe place solutions. The results also showed in some instances the training improved the prioritization of solutions according to the safe place methodology. The effects were of a similar magnitude for individuals and teams. Creative thinking training was shown to be a useful way to enhance the generation of safe place solutions to safety problems. Given that creative thinking skills can theoretically be applied to any area of problem solving, the enhancement of these skills are likely to yield wider benefits. Furthermore the enhancement of creative thinking accords well with the current industrial mandates for improved innovation.
- Description: Doctor of Philosophy
- Authors: Culvenor, John
- Date: 1997
- Type: Text , Thesis , PhD
- Full Text:
- Description: Occupational health and safety legislation in Australia and internationally is based on the safe place concept and the hierarchy of control. A safe place is best achieved at the design stage and consequently the education of engineers in safety has been a priority. There have been notable efforts at the integration of safety with engineering studies, and this should be an ongoing objective, however extensive integration is likely to be difficult at least in the short term. The challenge was to develop a supplemental, innovative way to improve the ability of engineers to develop safe place solutions. The hypothesis was that training in creative thinking would achieve this aim. The hierarchy of control methodology shares a strong relationship with creative thinking. Safe place thinking challenges assumptions in the same way that creative thinking seeks to escape dominant paradigms. For this reason creative thinking seems a natural aid to the safe place approach. This study tested the effect on safety design of a creative thinking program; de Bono’s six thinking hats method. Given a recognition that groups other than engineers impact on workplace design, a range of subjects were included; engineering students, technology students, industry safety advisers, and government safety advisers. In response to safety case studies, subjects were required to generate solutions and to prioritize potential solutions. Subjects worked on a range of problems, some individually and some in teams of three. Results show that training in creative thinking improved the generation of solutions to safety problems. As the number of solutions increased, the average quality of ideas was maintained, therefore the increased number of solutions was accompanied by a similar increase in good quality safe place solutions. The results also showed in some instances the training improved the prioritization of solutions according to the safe place methodology. The effects were of a similar magnitude for individuals and teams. Creative thinking training was shown to be a useful way to enhance the generation of safe place solutions to safety problems. Given that creative thinking skills can theoretically be applied to any area of problem solving, the enhancement of these skills are likely to yield wider benefits. Furthermore the enhancement of creative thinking accords well with the current industrial mandates for improved innovation.
- Description: Doctor of Philosophy
Type 2 diabetes mellitus management : a retrospective study in rural general practice
- Wyett, Ruby, Peck, Blake, Terry, Daniel
- Authors: Wyett, Ruby , Peck, Blake , Terry, Daniel
- Type: Text , Journal article
- Relation: Advances in Diabetes and Metabolism Vol. 7, no. 1 (), p. 1-7
- Full Text:
- Reviewed:
- Description: Type 2 Diabetes Mellitus (T2DM) is a chronic, progressive metabolic disease that is an international epidemic. General Practitioners (GPs) are the cornerstones of T2DM management. The aim of this study was to determine the scope of care and management of patients with T2DM within General Practice, while highlighting domains of success and areas where improvement can be made. Demographic and laboratory cross sectional data were collected by examining electronic patient records at one rural General Practice to address the aims of the study. Data included key management parameters of Hemoglobin A1c (HbA1c), estimated Glomerular Filtration Rate (eGFR), microalbuminuria, blood pressure and cholesterol levels, in addition to age, sex, and residential postcode. Further, data regarding the use of insulin, antihypertensive medications and lipid-lowering medications were collected and analyzed. Descriptive and inferential statistics were used and significance was determined at p
- Authors: Wyett, Ruby , Peck, Blake , Terry, Daniel
- Type: Text , Journal article
- Relation: Advances in Diabetes and Metabolism Vol. 7, no. 1 (), p. 1-7
- Full Text:
- Reviewed:
- Description: Type 2 Diabetes Mellitus (T2DM) is a chronic, progressive metabolic disease that is an international epidemic. General Practitioners (GPs) are the cornerstones of T2DM management. The aim of this study was to determine the scope of care and management of patients with T2DM within General Practice, while highlighting domains of success and areas where improvement can be made. Demographic and laboratory cross sectional data were collected by examining electronic patient records at one rural General Practice to address the aims of the study. Data included key management parameters of Hemoglobin A1c (HbA1c), estimated Glomerular Filtration Rate (eGFR), microalbuminuria, blood pressure and cholesterol levels, in addition to age, sex, and residential postcode. Further, data regarding the use of insulin, antihypertensive medications and lipid-lowering medications were collected and analyzed. Descriptive and inferential statistics were used and significance was determined at p
Regulation of the rabbit's once-daily pattern of nursing : A circadian or hourglass-dependent process?
- Apel, Sabine, Hudson, Robyn, Coleman, Grahame, Rodel, Heiko, Kennedy, Gerard
- Authors: Apel, Sabine , Hudson, Robyn , Coleman, Grahame , Rodel, Heiko , Kennedy, Gerard
- Date: 2020
- Type: Text , Journal article
- Relation: Chronobiology International Vol. 37, no. 8 (2020), p. 1151-1162
- Full Text:
- Reviewed:
- Description: The European rabbitOryctolagus cuniculushas an unusual pattern of nursing behavior. After giving birth in a nursery burrow (or laboratory nest box), the mother immediately leaves the young and only returns to nurse for a few minutes once approximately every 24 h. It has been assumed this schedule, like a variety of other functions in the rabbit, is under circadian control. This assumption has been largely based on findings from mothers only permitted restricted access to their young once every 24 h. However, in nature and in the laboratory, mothers with free access to young show nursing visits with a periodicity shorter than 24 h, that does not correspond to other behavioral and physiological rhythms entrained to the prevailing 24 h light/dark (LD) cycle. To investigate how this unusual, apparently non-circadian pattern might be regulated, we conducted two experiments using female Dutch-belted rabbits housed individually in cages designed to automatically register feeding activity and nest box visits. In Experiment 1 we recorded the behavior of 17 mothers with free access to their young under five different LD cycles with long photo and short scotoperiods, spanning the limits of entrainment of the rabbit's circadian system. Whereas feeding rhythms were entrained by LD cycles within the rabbit's circadian range of entrainment, nursing visits showed a consistently shorter periodicity regardless of the LD regimen, largely independent of the circadian system. In Experiment 2 we tested further 12 mothers under more conventional LD 16:8 cycles but "trained" by having access to the nest box restricted to 1 h at the same time each day for the first 7 d of nursing. Mothers were then allowed free access either when their young were left in the box (n= 6), or when the litter had been permanently removed (n= 6). Mothers with pups still present returned to nurse them on the following days according to a similarly advancing pattern to the mothers of Experiment 1 despite the previous 7 d of "training" to an experimentally enforced 24 h nursing schedule as commonly used in previous studies of rabbit maternal behavior. Mothers whose pups had been removed entered the box repeatedly several times on the first day of unrestricted access, but on subsequent days did so only rarely, and at times of day apparently unrelated to the previously scheduled access. We conclude that the pattern of the rabbit's once-daily nursing visits has a periodicity largely independent of the circadian system, and that this is reset at each nursing. When nursing fails to occur nest box visits cease abruptly, with mothers making few or no subsequent visits. Together, these findings suggest that the rabbit's once-daily pattern of nursing is regulated by an hourglass-type process with a period less than 24 h that is reset at each nursing, rather than by a circadian oscillator. Such a mechanism might be particularly adaptive for rhythms of short duration that should end abruptly with a sudden change in context such as death or weaning of the young.
- Description: This work was supported by the Australian Federal Government via a Postgraduate PhD Scholarship for Sabibe Apel [APA SA 1].
- Authors: Apel, Sabine , Hudson, Robyn , Coleman, Grahame , Rodel, Heiko , Kennedy, Gerard
- Date: 2020
- Type: Text , Journal article
- Relation: Chronobiology International Vol. 37, no. 8 (2020), p. 1151-1162
- Full Text:
- Reviewed:
- Description: The European rabbitOryctolagus cuniculushas an unusual pattern of nursing behavior. After giving birth in a nursery burrow (or laboratory nest box), the mother immediately leaves the young and only returns to nurse for a few minutes once approximately every 24 h. It has been assumed this schedule, like a variety of other functions in the rabbit, is under circadian control. This assumption has been largely based on findings from mothers only permitted restricted access to their young once every 24 h. However, in nature and in the laboratory, mothers with free access to young show nursing visits with a periodicity shorter than 24 h, that does not correspond to other behavioral and physiological rhythms entrained to the prevailing 24 h light/dark (LD) cycle. To investigate how this unusual, apparently non-circadian pattern might be regulated, we conducted two experiments using female Dutch-belted rabbits housed individually in cages designed to automatically register feeding activity and nest box visits. In Experiment 1 we recorded the behavior of 17 mothers with free access to their young under five different LD cycles with long photo and short scotoperiods, spanning the limits of entrainment of the rabbit's circadian system. Whereas feeding rhythms were entrained by LD cycles within the rabbit's circadian range of entrainment, nursing visits showed a consistently shorter periodicity regardless of the LD regimen, largely independent of the circadian system. In Experiment 2 we tested further 12 mothers under more conventional LD 16:8 cycles but "trained" by having access to the nest box restricted to 1 h at the same time each day for the first 7 d of nursing. Mothers were then allowed free access either when their young were left in the box (n= 6), or when the litter had been permanently removed (n= 6). Mothers with pups still present returned to nurse them on the following days according to a similarly advancing pattern to the mothers of Experiment 1 despite the previous 7 d of "training" to an experimentally enforced 24 h nursing schedule as commonly used in previous studies of rabbit maternal behavior. Mothers whose pups had been removed entered the box repeatedly several times on the first day of unrestricted access, but on subsequent days did so only rarely, and at times of day apparently unrelated to the previously scheduled access. We conclude that the pattern of the rabbit's once-daily nursing visits has a periodicity largely independent of the circadian system, and that this is reset at each nursing. When nursing fails to occur nest box visits cease abruptly, with mothers making few or no subsequent visits. Together, these findings suggest that the rabbit's once-daily pattern of nursing is regulated by an hourglass-type process with a period less than 24 h that is reset at each nursing, rather than by a circadian oscillator. Such a mechanism might be particularly adaptive for rhythms of short duration that should end abruptly with a sudden change in context such as death or weaning of the young.
- Description: This work was supported by the Australian Federal Government via a Postgraduate PhD Scholarship for Sabibe Apel [APA SA 1].
Assessing healthcare providers' performance with and without risk adjustment
- Authors: Morales-Silva, Daniel
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study focuses on how healthcare data can be used to draw comparisons between healthcare providers (surgeons or hospitals). Depending on the type of access to datasets, these comparisons can be done with or without risk adjustment. For us, risk adjustment refers to the use of patient-level information to explain variation in healthcare spending, resource utilisation and health outcomes. For unadjusted comparisons, we highlight the diagnostic potential that radar plots offer for reporting on outcome indicators. These outcome indicators were obtained from hospital admissions of patients undergoing certain surgical procedures. We address two drawbacks of radar plots: presence of missing information and order of indicators. By introducing a consolidated view at provider level, we define an uncomplicated ranking of providers which can be used to identify potential low and high performers. For risk adjusted comparisons, we introduce a novel and robust methodology that enables comparisons of healthcare providers across multiple hierarchies, namely, surgeons, teams, departments and hospitals, using a consistent approach. Our methodology puts the patient at the centre of the analysis, and thus, can be used for personalised predictions (e.g. expected length of stay, costs and probability of being transferred to intensive care unit). Our findings suggest that the observed variation in selected outcome indicators, such as length of stay and charges of healthcare providers, cannot be explained by patient characteristics alone. Importantly, we have also observed that the perceived performance, on selected outcome indicators, of providers can change substantially following risk adjustment. Healthcare is unique in that clinical expertise is essential in guiding decision making and in informing all statistical models that seek to describe patient outcomes. For future iterations of our models, we will seek greater clinical input.
- Description: Doctor of Philosophy
- Authors: Morales-Silva, Daniel
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study focuses on how healthcare data can be used to draw comparisons between healthcare providers (surgeons or hospitals). Depending on the type of access to datasets, these comparisons can be done with or without risk adjustment. For us, risk adjustment refers to the use of patient-level information to explain variation in healthcare spending, resource utilisation and health outcomes. For unadjusted comparisons, we highlight the diagnostic potential that radar plots offer for reporting on outcome indicators. These outcome indicators were obtained from hospital admissions of patients undergoing certain surgical procedures. We address two drawbacks of radar plots: presence of missing information and order of indicators. By introducing a consolidated view at provider level, we define an uncomplicated ranking of providers which can be used to identify potential low and high performers. For risk adjusted comparisons, we introduce a novel and robust methodology that enables comparisons of healthcare providers across multiple hierarchies, namely, surgeons, teams, departments and hospitals, using a consistent approach. Our methodology puts the patient at the centre of the analysis, and thus, can be used for personalised predictions (e.g. expected length of stay, costs and probability of being transferred to intensive care unit). Our findings suggest that the observed variation in selected outcome indicators, such as length of stay and charges of healthcare providers, cannot be explained by patient characteristics alone. Importantly, we have also observed that the perceived performance, on selected outcome indicators, of providers can change substantially following risk adjustment. Healthcare is unique in that clinical expertise is essential in guiding decision making and in informing all statistical models that seek to describe patient outcomes. For future iterations of our models, we will seek greater clinical input.
- Description: Doctor of Philosophy