Spatial vision within egocentric and exocentric frames of reference

The extent to which perceptual judgements within egocentric and exocentric frames of reference are subject to illusory disturbances and long term modifications is discussed. It is argued that well known spatial illusions, such as the oculogyral illusion and induced visual motion have usually been discussed without proper attention being paid to the frame of reference within which they occur, and that this has led to the construction of inadequate theories and inappropriate procedures for testing them

Daily to Seasonal Moisture Signals Present in Sub-Annual Tree-Ring Data

In recent decades, there has been an increase in the development of sub-annual earlywood (EW) and latewood (LW) width tree-ring chronologies that have been used to make long-term inferences about discrete seasonal moisture variability for different regions of North America. This doctoral research developed a new network of EW, LW, and adjusted latewood (LWa) tree-ring chronologies from the western Great Plains. These chronologies were used to reconstruct 300+ years of spring and summer moisture variability over the northern and southern Plains. The reconstructions document new information about the long-term seasonal climate history of the Great Plains, including the unusual nature of persistent spring dryness in the mid- to late-19th century and the unprecedented summer drought conditions of the 1930s. Using daily precipitation data, a regional average of four LWa chronologies from eastern Colorado was shown to be significantly correlated (r = 0.83) with the heaviest rainfall day that occurs during the wettest two weeks of year in late-July. A 238-year reconstruction estimates there has been an increase in the frequency of the most extreme events (\u3e90th percentile), especially during the late-20th century. The heaviest midsummer rainfall days are associated with strong Canadian cold fronts and a negatively tilted upper-level ridge over the western United States that increases atmospheric moisture advection from the Gulf of Mexico and Pacific. Sixty-nine Douglas-fir and ponderosa pine LWa chronologies from the Southwest were compared with gridded daily rainfall data to objectively define the length and timing of the precipitation intervals best correlated with independent LW growth during the warm season. The majority of LWa chronologies are significantly correlated with early-season monsoon precipitation and are related to the start of the local monsoon season. Ponderosa pine is largely correlated with sub-monthly precipitation totals during the early-monsoon season across the Southwest. Douglas-fir tends to be correlated with precipitation summed over longer intervals, and there is substantial geographic variability in terms of the timing of the best warm season precipitation signals. The intensity of the monsoon during the month of July appears to be the primary factor in determining geographically which sites contain a monsoon precipitation signal

Clinical quality and performance measurement in the prehospital emergency medical services in the low-to-middle-income setting : developing clinical quality and performance indicators as a measure of care in South Africa

BACKGROUND: Measuring quality and safety in any healthcare setting however is highly contextual, and depends on the manner in which quality is defined or viewed within that setting. It is this contextual nature that has provoked significant debate and hindered efforts at developing formal standards or criteria for measuring quality and safety in healthcare, regardless of setting. Historically, performance within the Emergency Medical Services (EMS) delivering prehospital emergency care has been assessed primarily based on response times. While easy to measure and valued by the public, overall, response time targets are a poor predictor of quality of care and clinical outcomes. AIM: The overall aim of the research was to develop a framework for clinical quality and performance-based assessment of prehospital emergency care for use in the South African EMS. METHOD: The research was divided amongst four studies, with each study constituting one of the overall research objectives. Study I was a sequential explanatory mixed methods study with the aim of understanding the knowledge, attitudes and practices of clinical quality and performance assessment amongst South African EMS personnel. Part 1 consisted of a web- based cross-sectional survey, and Part 2 consisted of semi-structured telephonic interviews of select participants from Part 1 to explore the results of the survey. Descriptive statistics were carried out to summarise and present all survey items, and conventional content analysis employed to analyse the interview data. Study II utilised a three round modified Delphi study to identify, refine and review a list of appropriate quality indicators for potential use in the South African EMS setting. For Study III a novel quality indicator appraisal protocol was developed consisting of two categorical-based appraisal methods, combined with the qualitative analysis of their consensus application, and tested against the outcomes of Study II. Descriptive statistics were utilised to describe and summarize the categorical based appraisal data. Inter-rater reliability was calculated using percentage agreement and Gwet’s AC1. Correlation between the individual methods and the protocol was calculated using Spearman’s rank Correlation and z-test. Conventional content analysis was utilised to analyse the group discussions. Study IV utilised a multiple exploratory case study design to evaluate the current state of quality systems in the South African EMS. A formative assessment was conducted on the quality systems of four provincial EMS and one national private EMS, following which semi-structured interviews were conducted to further explore the results obtained from the formative assessment, supported by multiple secondary data sources. Descriptive statistics were utilised to describe and summarize the formative assessment. Conventional content analysis was utilised to analyse the interview data and document analysis utilised to sort and analyse the supporting data. RESULTS: Despite relatively poor knowledge of organisational-specific quality systems, understanding of the core components and importance of quality systems was demonstrated. The role of these systems in the Low to Middle Income Country setting (LMICs) was supported by participants, where the importance of context, system transparency, reliability and validity were essential towards achieving ongoing success and utilisation. The role of leadership and communication towards the effective facilitation of such a system was equally identified. Participating services generally scored higher for structure and planning. Measurement and improvement were found to be more dependent on utilisation and perceived mandate. There was a relatively strong focus on clinical quality assessment within the private service, whereas in the provincial systems, measures were exclusively restricted to call times with little focus on clinical care. Staff engagement and programme evaluation were generally among the lowest scores. A multitude of contextual factors were identified that affected the effectiveness of quality systems, centred around leadership, vision and mission, and quality system infrastructure and capacity, guided by the need for comprehensive yet pragmatic strategic policies and standards. A total, 104 quality indicators reached consensus agreement including, 90 clinical QIs, across 15 subcategories, and 14 non-clinical QIs across two subcategories. Amongst the clinical category, airway management (n=13 QIs; 14%); out-of-hospital cardiac arrest (n=13 QIs; 14%); and acute coronary syndromes (n=11 QIs; 12%) made up the majority. Within the non-clinical category, adverse events made up the significant majority with nine QIs (64%). There was mixed inter-rater reliability of the individual methods. There was similarly poor to moderate correlation of the results obtained between the individual methods (Spearman’s rank correlation=0.42,p<0.001). From a series of 104 QIs, 11 were identified that were shared between the individual methods. A further 19 QIs were identified and not shared by each method, highlighting the benefits of a multimethod approach. CONCLUSION: For the purposes of this study we focused on the technical competence aspect of quality, in developing our measurement framework. Towards this, we identified a significant number of QIs assessed to be valid and feasible for the South African prehospital emergency care setting. The majority of which are centred around clinically focused processes of care, measures that are lacking in current performance assessment in EMS in South Africa. However, we also discovered the importance and influencing role of the individual practitioners and quality system in which the QIs will be implemented, a point highlighted across all the methodologies and studies. Given the potential magnitude of this influence, it is of the utmost importance that any measurement framework examining technical quality, have equal in-depth understanding of these factors in order to be successful

Design and Prototyping of a 3DOF Worm-drive Robot Arm

PEARLDOI for this publication Labels There are no labels on this output. Add labels Many designs for robot arms exist. Here we present an affordable revolute arm, capable of executing simple pick-and-place tasks. The arm employs a double parallelogram structure, which ensures its endpoint angle in the plane of the upper arm remains fixed without the need for additional actuation. Its limbs are fabricated from circular tubes made from bonded carbon fiber, to ensure low moving mass while maintaining high rigidity. All custom structural elements of the arm are produced via 3D printing. We employ worm-drive DC motor actuation to ensure that stationary configurations are maintained without the necessity of continuous motor power. Our discussion encompasses an analysis of the arm’s kinematics. A simulation of the arm’s operation was carried out in MATLAB, revealing key operational metrics. In conclusion, we achieved extrinsic endpoint position tracking by implementing its inverse kinematics and PID control using a microcontroller. We also demonstrate the arm’s functionality through simple movement tracking and object manipulation tasks

Rapid presentation rate negatively impacts the contiguity effect in free recall

It is well-known that in free recall participants tend to recall words presented close together in time in sequence, reflecting a form of temporal binding in memory. This contiguity effect is robust, having been observed across many different experimental manipulations. In order to explore a potential boundary on the contiguity effect, participants performed a free recall task in which items were presented at rates ranging from 2 Hz to 8 Hz. Participants were still able to recall items even at the fastest presentation rate, though accuracy decreased. Importantly, the contiguity effect flattened as presentation rates increased. These findings illuminate possible constraints on the temporal encoding of episodic memories.http://sites.bu.edu/tcn/files/2019/05/RSVP_FR.pdfAccepted manuscrip

New Zealand regions, 1986 – 2001: Hospitalisation and some related health facts

Once age and gender composition is controlled for, regional health differentials are a function of problems of health service delivery, of socio-economic variance, and overall Māori Pakeha health differences. They indicate relative levels of exclusion and of inequality. This paper shows that these differentials follow in general the patterns seen in other papers in this series

The Economics of Fuel Economy Standards

This paper discusses several rationales for the Corporate Average Fuel Economy (CAFE) program, including reduced oil dependence, reduced greenhouse gas emissions, and the possibility that fuel saving benefits from higher standards might exceed added vehicle costs. We then summarize what can be said about the welfare effects of tightening standards, accounting for prior fuel taxes, and perverse effects on congestion and traffic accidents through the impact of improved fuel economy on the incentive to drive. Implications of CAFE on local air pollution, and the controversy over CAFE, vehicle weight, and road safety, are also discussed. Finally, we describe ways in which the existing CAFE program could be substantially improved and identify a variety of alternative, and much superior, policy approaches.

A theoretical and experimental analysis of adaption to asymmetrical and distorted visual stimulation

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Learning to Pronounce First Words in Three Languages: An Investigation of Caregiver and Infant Behavior Using a Computational Model of an Infant

Words are made up of speech sounds. Almost all accounts of child speech development assume that children learn the pronunciation of first language (L1) speech sounds by imitation, most claiming that the child performs some kind of auditory matching to the elements of ambient speech. However, there is evidence to support an alternative account and we investigate the non-imitative child behavior and well-attested caregiver behavior that this account posits using Elija, a computational model of an infant. Through unsupervised active learning, Elija began by discovering motor patterns, which produced sounds. In separate interaction experiments, native speakers of English, French and German then played the role of his caregiver. In their first interactions with Elija, they were allowed to respond to his sounds if they felt this was natural. We analyzed the interactions through phonemic transcriptions of the caregivers' utterances and found that they interpreted his output within the framework of their native languages. Their form of response was almost always a reformulation of Elija's utterance into well-formed sounds of L1. Elija retained those motor patterns to which a caregiver responded and formed associations between his motor pattern and the response it provoked. Thus in a second phase of interaction, he was able to parse input utterances in terms of the caregiver responses he had heard previously, and respond using his associated motor patterns. This capacity enabled the caregivers to teach Elija to pronounce some simple words in their native languages, by his serial imitation of the words' component speech sounds. Overall, our results demonstrate that the natural responses and behaviors of human subjects to infant-like vocalizations can take a computational model from a biologically plausible initial state through to word pronunciation. This provides support for an alternative to current auditory matching hypotheses for how children learn to pronounce