title: Human visual-vestibular interaction during curvilinear motion in VR

authors: Garnett, Aden C.

abstract: When people move through the world they use retinal image motion to form an estimate of self-motion, although how this is achieved is not yet fully understood. Furthermore, the process is not fool-proof and many conditions create incorrect percepts of self-motion. In particular, experiencing rotation makes it difficult for humans to correctly perceive heading during movement from visual input alone. 

Here we re-examined human perception of rotation during true and simulated curvilinear motion. Broadly, this was done by simulating movement along various paths using currently available head-mounted stereoscopic virtual reality displays. These displays overcome many of the shortcomings of historical equipment but also represent a significant departure from established setups. As such, the first two experiments, presented together in Chapter 2, replicated experiments from Banks, Ehrlich, Backus, and Crowell (1996) and Crowell, Banks, Shenoy, and Andersen (1998). This was to aid in determining the suitability of consumer-grade virtual reality headsets for self-motion perception research and to provide a point of comparison between this thesis and historical works. 

Following confirmation that the VR devices were suitable for research we developed a virtual line-based bendable response tool. This tool made use of tracked hand controllers to facilitate fast and intuitive reporting of self-motion perception without confounding heading and rotation perception errors. Using this tool we confirmed reports of curvilinear motion perception during linear travel with rotation. We then measured perception of heading and curvature during travel on linear paths of increasingly eccentric heading, finding that eccentric headings elicited perceptions of curvature. We also measured perceptions of travel along curvilinear paths so that a model of human visual-vestibular interaction \cite{perrone2018visual} as it applies to heading perception could be tested against participant performance. Finally, predictions from this model prompted us to measure curvilinear path perception while using a rotating chair that allowed us to provide a rough congruent vestibular signal.

Overall, we found consistent large individual differences in perception across all motion types, although each individual's perceptions were internally consistent. Furthermore, we found that participants perceived curvature while travelling on not only curvilinear paths, but also on linear paths with rotation and linear paths with eccentric headings. The tested model, as implemented, matched participant results well, proving able to explain the majority of the individual differences. Finally, we found that providing a rough congruent vestibular signal resulted in participants perceiving less curved paths compared to when the vestibular signal indicated no rotation.

text: Human visual-vestibular interaction during curvilinear motion in VR When people move through the world they use retinal image motion to form an estimate of self-motion, although how this is achieved is not yet fully understood. Furthermore, the process is not fool-proof and many conditions create incorrect percepts of self-motion. In particular, experiencing rotation makes it difficult for humans to correctly perceive heading during movement from visual input alone. 

Here we re-examined human perception of rotation during true and simulated curvilinear motion. Broadly, this was done by simulating movement along various paths using currently available head-mounted stereoscopic virtual reality displays. These displays overcome many of the shortcomings of historical equipment but also represent a significant departure from established setups. As such, the first two experiments, presented together in Chapter 2, replicated experiments from Banks, Ehrlich, Backus, and Crowell (1996) and Crowell, Banks, Shenoy, and Andersen (1998). This was to aid in determining the suitability of consumer-grade virtual reality headsets for self-motion perception research and to provide a point of comparison between this thesis and historical works. 

Following confirmation that the VR devices were suitable for research we developed a virtual line-based bendable response tool. This tool made use of tracked hand controllers to facilitate fast and intuitive reporting of self-motion perception without confounding heading and rotation perception errors. Using this tool we confirmed reports of curvilinear motion perception during linear travel with rotation. We then measured perception of heading and curvature during travel on linear paths of increasingly eccentric heading, finding that eccentric headings elicited perceptions of curvature. We also measured perceptions of travel along curvilinear paths so that a model of human visual-vestibular interaction \cite{perrone2018visual} as it applies to heading perception could be tested against participant performance. Finally, predictions from this model prompted us to measure curvilinear path perception while using a rotating chair that allowed us to provide a rough congruent vestibular signal.

Overall, we found consistent large individual differences in perception across all motion types, although each individual's perceptions were internally consistent. Furthermore, we found that participants perceived curvature while travelling on not only curvilinear paths, but also on linear paths with rotation and linear paths with eccentric headings. The tested model, as implemented, matched participant results well, proving able to explain the majority of the individual differences. Finally, we found that providing a rough congruent vestibular signal resulted in participants perceiving less curved paths compared to when the vestibular signal indicated no rotation.

year: 2020

title: Patient and carer perceived barriers to early presentation and diagnosis of lung cancer: a systematic review.

authors: Cassim, Shemana

subjects: Barrier to diagnosis

abstract: BACKGROUND: Lung cancer is typically diagnosed at a late stage. Early presentation and detection of lung cancer symptoms is critical to improving survival but can be clinically complicated and as yet a robust screening method for diagnosis is not available in routine practice. Accordingly, the barriers to help-seeking behaviour and diagnosis need to be considered. This review aimed to document the barriers to early presentation and diagnosis of lung cancer, based on patient and carer perspectives. 
METHODS: A systematic review of databases was performed for original, English language articles discussing qualitative research on patient perceived barriers to early presentation and diagnosis of lung cancer. Three major databases were searched: Scopus, PubMed and EBSCOhost. References cited in the selected studies were searched for further relevant articles. 
RESULTS: Fourteen studies met inclusion criteria for review. Barriers were grouped into three categories: healthcare provider and system factors, patient factors and disease factors. 
CONCLUSIONS: Studies showed that the most frequently reported barriers to early presentation and diagnosis of lung cancer reported by patients and carers related to poor relationships between GPs and patients, a lack of access to services and care for patients, and a lack of awareness of lung cancer symptoms and treatment. Addressing these barriers offers opportunities by which rates of early diagnosis of lung cancer may be improved.

text: Patient and carer perceived barriers to early presentation and diagnosis of lung cancer: a systematic review. BACKGROUND: Lung cancer is typically diagnosed at a late stage. Early presentation and detection of lung cancer symptoms is critical to improving survival but can be clinically complicated and as yet a robust screening method for diagnosis is not available in routine practice. Accordingly, the barriers to help-seeking behaviour and diagnosis need to be considered. This review aimed to document the barriers to early presentation and diagnosis of lung cancer, based on patient and carer perspectives. 
METHODS: A systematic review of databases was performed for original, English language articles discussing qualitative research on patient perceived barriers to early presentation and diagnosis of lung cancer. Three major databases were searched: Scopus, PubMed and EBSCOhost. References cited in the selected studies were searched for further relevant articles. 
RESULTS: Fourteen studies met inclusion criteria for review. Barriers were grouped into three categories: healthcare provider and system factors, patient factors and disease factors. 
CONCLUSIONS: Studies showed that the most frequently reported barriers to early presentation and diagnosis of lung cancer reported by patients and carers related to poor relationships between GPs and patients, a lack of access to services and care for patients, and a lack of awareness of lung cancer symptoms and treatment. Addressing these barriers offers opportunities by which rates of early diagnosis of lung cancer may be improved.

year: 2019-01-08

title: A late-Holocene and prehistoric record of environmental change from Lake Waikaremoana, New Zealand

authors: Newnham, Rewi M.

subjects: Palynology

abstract: Further evidence in support of a late pre-European (Polynesian) settlement of New Zealand is provided by an 1850-year-long tephropalynological record from a remote region in New Zealand's North Island. The earliest unequivocally anthropogenic forest clearance is estimated from sedimentation rates to have occurred c. 375 14C years BP (c. ad 1523–1631), although the radiocarbon chronology, shown by tephrochron ology to be erroneous due to hard-water effects, suggested this occurred c. 900 years earlier. Delineation of the anthropogenic era, and the distinction between human activity and other agents of environmental change in the pollen/spore diagram, are supported by cluster analysis and detrended correspondence analysis. Two distinct phases of forest clearance are evident during the pre-European era, reflecting local changes either in population pressure or settlement patterns. We note that the lull between the two phases of forest clearance coincides with the maximum of the ‘Little Ice Age’ within the period c. late ad 1600s to early 1800s.

text: A late-Holocene and prehistoric record of environmental change from Lake Waikaremoana, New Zealand Further evidence in support of a late pre-European (Polynesian) settlement of New Zealand is provided by an 1850-year-long tephropalynological record from a remote region in New Zealand's North Island. The earliest unequivocally anthropogenic forest clearance is estimated from sedimentation rates to have occurred c. 375 14C years BP (c. ad 1523–1631), although the radiocarbon chronology, shown by tephrochron ology to be erroneous due to hard-water effects, suggested this occurred c. 900 years earlier. Delineation of the anthropogenic era, and the distinction between human activity and other agents of environmental change in the pollen/spore diagram, are supported by cluster analysis and detrended correspondence analysis. Two distinct phases of forest clearance are evident during the pre-European era, reflecting local changes either in population pressure or settlement patterns. We note that the lull between the two phases of forest clearance coincides with the maximum of the ‘Little Ice Age’ within the period c. late ad 1600s to early 1800s.

year: 1998