55 research outputs found
A step towards non-invasive characterization of the human frontal eye fields of individual subjects
No full textBackground: Identifying eye movement related areas in the frontal lobe has a long history, with microstimulation in monkeys producing the most clear-cut results. For humans, however, there is still no consensus about the location and the extent of the frontal eye field (FEF). There is also no simple non-invasive method for unambiguously defining the FEF in individual subjects, a prerequisite for clinical applications. Here we explore the use of magnetoencephalography (MEG) for the non-invasive identification and characterization of FEF activity in an individual subject.Methods: We mapped human brain activity before, during and after saccades by applying tomographic analysis to MEG data. Statistical parametric maps and circular statistics produced plausible FEF loci, but no unambiguous definition for individual subjects. Here we first computed the spectral decomposition and correlation with electrooculogram (EOG) of the tomographic brain activations. For each of these two measures statistical comparisons were made between different saccades.Results: In this paper, we first review the frontal cortex activations identified in earlier animal and human studies and place the putative human FEFs in a well-defined anatomical framework. This framework is then used as reference for describing the results of new Fourier analysis of the tomographic solutions comparing active saccade tasks and their controls. The most consistent change in the dorsal frontal cortex was at the putative left FEF, for both saccades to the left and right. The asymmetric result is consistent with the 1-way callosal traffic theory. We also showed that the new correlation analysis had its most consistent change in the contralateral putative FEF. This result was obtained for EOG latencies before saccade onset with delays of a few hundreds of milliseconds (FEF activity leading the EOG) and only for visual cues signaling the execution of a saccade in a previously defined saccade direction.Conclusions: The FEF definition derived from microstimulation describes only one of the areas in the dorsal lateral frontal lobe that act together to plan, prepare and execute a saccade. The definition and characterization of these areas in an individual subject can be obtained from non-invasive MEG measurements.<br/
Falcated Teal:
No full text1994Purchased for the Camosun College Art Collection by the Camosun College Cultural Enhancement Committee from the Art Gallery of Greater Victoria (Art Rental and Sales Gallery).James Fenwick Lansdowne (Order of Canada, Order of BC, Royal Canadian Academy of the Arts), was an internationally renowned wildlife artist and author. Born to British parent in Hong Kong in 1937, Lansdowne grew up in Victoria, BC and was taught to paint by his mother, an accomplished artist trained in Chinese watercolour painting. He began his artistic career at a young age presenting his first exhibition at the Royal Ontario Museum at the age of nineteen. His work has been closely compared to the paintings of John James Audubon, as it often portrayed a specific bird species over a neutral coloured background. Lansdowne’s work however has been lauded for its life-like realism and ability to present birds in naturalistic poses. He studies his subjects in their natural habitat and paints them in gouache. In 1977, Lansdowne was made an Officer of the Order of Canada, and in 1979, received an honourary Doctor of Laws from the University of Victoria. Lansdowne’s works have exhibited internationally at museums and galleries including Audubon House in New York, London’s Truon Galleries, and the Smithsonian Institute in Washington DC.
ARTIST INFO: Times Colonist Obituary: http://www.legacy.com/obituaries/timescolonist/obituary.aspx?n=james-fenwick-lansdowne&pid=114495190 (Accessed January 9, 2017); CBC Obituary: http://www.cbc.ca/news/entertainment/renowned-b-c-bird-artist-and-author-james-fenwick-lansdowne-dies-at-71-1.694563 (Accessed January 9, 2017); University of Victoria Collection Search Results: http://collection.legacy.uvic.ca/index.php?artist_id=2123&artist_action=get_art_w_bio (Accessed February 26, 2017)Robbyn LanningGouache is an watermedia which possesses qualities of both watercolour and acrylic/oil paints. Similar to watercolour paint, gouache has a matte finish, can be rewet, and can permeate its paper support. Like acrylic or oil paints, gouache is opaque and can also be used to form a superficial layer on top of its support.
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Interocular yoking in human saccades examined by mutual information analysis
No full textBackground: Saccadic eye movements align the two eyes precisely to foveate a target. Trial-by-trial variance of eye movement is always observed within an identical experimental condition. This has often been treated as experimental error without addressing its significance. The present study examined statistical linkages between the two eyes’ movements, namely interocular yoking, for the variance of eye position and velocity.Methods: Horizontal saccadic movements were recorded from twelve right-eye-dominant subjects while they decided on saccade direction in Go-Only sessions and on both saccade execution and direction in Go/NoGo sessions. We used infrared corneal reflection to record simultaneously and independently the movement of each eye. Quantitative measures of yoking were provided by mutual information analysis of eye position or velocity, which is sensitive to both linear and non-linear relationships between the eyes’ movements. Our mutual information analysis relied on the variance of the eyes movements in each experimental condition. The range of movements for each eye varies for different conditions so yoking was further studied by comparing GO-Only vs. Go/NoGo sessions, leftward vs. rightward saccades.Results: Mutual information analysis showed that velocity yoking preceded positional yoking. Cognitive load increased trial variances of velocity with no increase in velocity yoking, suggesting that cognitive load may alter neural processes in areas to which oculomotor control is not tightly linked. The comparison between experimental conditions showed that interocular linkage in velocity variance of the right eye lagged that of the left eye during saccades.Conclusions: We conclude quantitative measure of interocular yoking based on trial-to-trial variance within a condition, as well as variance between conditions, provides a powerful tool for studying the binocular movement mechanism<br/
Rickettsiales and rickettsial diseases in Australia
No full textCurrently, there are 12 known Rickettsiales species in Australia. However research into the diversity and range of these agents in Australia is still far from complete.
A sero-epidemiological study was undertaken around the city of Launceston in Tasmania, Australia to determine the level of exposure to spotted fever group (SFG) rickettsia among the local cat and dog population. The study showed that over 50% of the dogs and cats tested were positive for SFG rickettsiae antibodies. However, no correlation was observed between the animals’ health and seropositivity at the time of testing.
Ixodes tasmani ticks collected from Tasmanian devils in Tasmania were tested for the presence of SFG and typhus group (TG) rickettsiae using a specific real time PCR (qPCR), and 55% were found to be positive. The gltA, rompA, rompB and sca4 genes were then sequenced. Using the current criteria this new rickettsia qualified as a Candidatus species, and was named Candidatus Rickettsia tasmanensis, after the location from which it was first detected.
Soft ticks of the species Argas dewae were collected from bat roosting boxes north of Melbourne. Of the ten ticks collected, seven (70%) were positive for SFG rickettsiae using the qPCR mentioned above. An isolate was obtained using cell culture isolation methods and the rrs, gltA, rompA, rompB and sca4 genes were sequenced. Using the current criteria this new rickettsia qualified as a novel species, and was tentatively named Rickettsia argasii sp. nov. after the tick genus from which it was isolated.
Four family members and their neighbour living in metropolitan Victoria became ill after exposure to a flea-infested kitten. Initial serological analysis indicated a typhus group (TG) rickettsial infection. However, testing of fleas from the group of cats in Lara, Victoria, where the kitten originated, revealed the presence of R. felis, the agent of cat flea typhus. This was the first case of human infection with R. felis in Australia and the first detection of R. felis in fleas in Victoria.
A tourist returning to Australia from the United Arab Emirates was diagnosed with a scrub typhus group (STG) rickettsial infection and the agent was isolated from their blood. Analysis of the rrs and 47kDa genes showed significant divergence compared to all available strains of Orientia tsutsugamushi. Due to the degree of genetic divergence and the geographically unique origin of this isolate it was considered to be a new species, which has been tentatively named Orientia chuto, with ‘chuto’ being Japanese for ‘Middle East’.
Dogs in central and northern Australia were tested for Anaplasma platys using a specifically designed real-time PCR (qPCR) assay. Of the 68 dogs tested, 27 (40%) were positive for A. platys DNA, including six dogs from Western Australia. This was the first report of A. platys in Western Australia.
These studies offer an insight into the range and diversity of Rickettsiales and rickettsial diseases previously unrecognised in Australia
Employee worktime control moderates the effects of job strain and effort-reward imbalance on sickness absence: the 10-town study
No full textDevelopment of a cost-effectiveness model for optimisation of the screening interval in diabetic retinopathy screening
No full textBACKGROUND:
The English NHS Diabetic Eye Screening Programme was established in 2003. Eligible people are invited annually for digital retinal photography screening. Those found to have potentially sight-threatening diabetic retinopathy (STDR) are referred to surveillance clinics or to Hospital Eye Services.
OBJECTIVES:
To determine whether personalised screening intervals are cost-effective.
DESIGN:
Risk factors were identified in Gloucestershire, UK using survival modelling. A probabilistic decision hidden (unobserved) Markov model with a misgrading matrix was developed. This informed estimation of lifetime costs and quality-adjusted life-years (QALYs) in patients without STDR. Two personalised risk stratification models were employed: two screening episodes (SEs) (low, medium or high risk) or one SE with clinical information (low, medium-low, medium-high or high risk). The risk factor models were validated in other populations.
SETTING:
Gloucestershire, Nottinghamshire, South London and East Anglia (all UK).
PARTICIPANTS:
People with diabetes in Gloucestershire with risk stratification model validation using data from Nottinghamshire, South London and East Anglia.
MAIN OUTCOME MEASURES:
Personalised risk-based algorithm for screening interval; cost-effectiveness of different screening intervals.
RESULTS:
Data were obtained in Gloucestershire from 12,790 people with diabetes with known risk factors to derive the risk estimation models, from 15,877 people to inform the uptake of screening and from 17,043 people to inform the health-care resource-usage costs. Two stratification models were developed: one using only results from previous screening events and one using previous screening and some commonly available GP data. Both models were capable of differentiating groups at low and high risk of development of STDR. The rate of progression to STDR was 5 per 1000 person-years (PYs) in the lowest decile of risk and 75 per 1000 PYs in the highest decile. In the absence of personalised risk stratification, the most cost-effective screening interval was to screen all patients every 3 years, with a 46% probability of this being cost-effective at a £30,000 per QALY threshold. Using either risk stratification models, screening patients at low risk every 5 years was the most cost-effective option, with a probability of 99-100% at a £30,000 per QALY threshold. For the medium-risk groups screening every 3 years had a probability of 43-48% while screening high-risk groups every 2 years was cost-effective with a probability of 55-59%.
CONCLUSIONS:
The study found that annual screening of all patients for STDR was not cost-effective. Screening this entire cohort every 3 years was most likely to be cost-effective. When personalised intervals are applied, screening those in our low-risk groups every 5 years was found to be cost-effective. Screening high-risk groups every 2 years further improved the cost-effectiveness of the programme. There was considerable uncertainty in the estimated incremental costs and in the incremental QALYs, particularly with regard to implications of an increasing proportion of maculopathy cases receiving intravitreal injection rather than laser treatment. Future work should focus on improving the understanding of risk, validating in further populations and investigating quality issues in imaging and assessment including the potential for automated image grading
Evaluating an extended rehabilitation service for stroke patients (EXTRAS): Study protocol for a randomised controlled trial
No full textBackground: Development of longer term stroke rehabilitation services is limited by lack of evidence of effectiveness for specific interventions and service models. We describe the protocol for a multicentre randomised controlled trial which is evaluating an extended stroke rehabilitation service. The extended service commences when routine 'organised stroke care' (stroke unit and early supported discharge (ESD)) ends. Methods/design: This study is a multicentre randomised controlled trial with health economic and process evaluations. It is set within NHS stroke services which provide ESD. Participants are adults who have experienced a new stroke (and carer if appropriate), discharged from hospital under the care of an ESD team. Discussion: The provision of longer term support for stroke survivors is currently limited. The results from this trial will inform future stroke service planning and configuration. Trial registration: This trial was registered with ISRCTN (identifier: ISRCTN45203373) on 9 August 2012
Novel approaches to evaluate the impact of the SAFE strategy on trachoma and other neglected tropical diseases in Amhara National Regional State, Ethiopia
No full textBackground: Trachoma, a blinding bacterial disease of the ocular surface, is the leading
cause of infectious blindness, responsible for the visual impairment of 2.2 million people
worldwide and an estimated economic loss of US$ 5.3 billion annually. Blinding trachoma,
considered a neglected tropical disease, is targeted for global elimination as a public health
problem by the year 2020. To achieve elimination, the World Health Organization (WHO)
recommends implementing an integrated intervention package of surgery, antibiotics, facial
cleanliness, and environmental improvement, known as the SAFE strategy. Surgery aims to
correct trichiasis, the blinding anatomical condition of inward turning lashes touching the eye.
Antibiotics are distributed annually to endemic communities to treat relatively asymptomatic
ocular Chlamydia trachomatis infections to reduce the infectious reservoir. The promotion of
facial cleanliness and environmental improvements, use of water and latrines for hygiene
and sanitation, both target interrupting transmission of the infection. Of the 325 million
persons estimated living in trachoma endemic communities, over 70% reside in sub-Saharan
Africa. Within the region, Ethiopia, Nigeria, and South Sudan are estimated to have the
highest burden of disease. The SAFE strategy in Ethiopia has been implemented since 2007
targeting all 17 million residents of the Amhara National Regional State.
Goals and specific objectives: The goal of this PhD thesis was to investigate novel
approaches of measuring the impact of SAFE interventions on trachoma and other
neglected tropical diseases within the context of a national elimination programme as
implemented in the Amhara National Regional State of Ethiopia. The specific operational
research objectives were to determine whether areas receiving 3-5 years of interventions
had achieved elimination by applying new evaluation guidelines; whether new electronic
data collection technology could facilitate impact evaluation; whether SAFE interventions
had any impact on trachomatous scarring (TS) among children; whether school-based
surveys might serve as an alternative method to assess trachoma; and whether SAFE
interventions have had any impact on intestinal parasitic infections.
Methods: Data collection for the thesis project occurred in three phases. The first phase
involved the implementation of a population-based, cross-sectional study utilising a cluster
random sampling design to survey 360 communities in South Wollo zone to estimate
prevalence of trachoma after three years of SAFE interventions. Data was collected using
standard paper-based questionnaires. The second phase involved the development and
field-testing of a new electronic data collection system in a pilot study utilising a mixed,
quantitative and qualitative, study design. The last phase involved the implementation of
another population-based cross-sectional study in South Gondar zone after receiving five
years of SAFE interventions. The same sampling methodology was used to survey another
360 communities, yet integrating both assessment of trachoma and intestinal parasitic
infections. Additionally, data was collected strictly by the newly developed electronic system.
Clinical signs of trachoma were individually assessed using the WHO simplified trachoma
grading system. Intestinal parasitic infections among children aged 2-15 years were
determined by concentrating preserved stool specimens with ether for microscopic
examination.
Results: From 714 communities in the two zones, 72,452 persons were examined for
trachoma. The prevalence of trachomatous inflammation follicular (TF) among children aged
1-9 years was 26.4% in South Wollo and 25.9% in South Gondar zone. Trachomatous
inflammation intense (TI) was less prevalent than TF; 4.3% and 7.0% in South Wollo and
South Gondar respectively. TT prevalence in the two zones suggest that over 59,000
persons are estimated to have trichiasis and in need of surgery. In South Gondar the
prevalence of TS among children under the age of 11 years has declined from 24.9% in
2000 to 2.2% in 2011. While declines in intense inflammation and scarring were observed
among children since intervention, the WHO targets for elimination have not been achieved.
The android-based tablet computer and the standard paper questionnaire were
comparable in regards to time required to collect data during the pilot study, proportion of
mistakes made while recording data and costs when considering data entry of paper
questionnaires. Data recorders preferred to collect data electronically even though initially
they felt the tablet interrupted their connection with the interview respondents. Electronic
data collection resulted in completion of the large-scale surveys from preparation to
presentation of results in 35% less time (one month earlier) than the standard paper-based
surveys.
An analysis of 75,864 children examined in community-based surveys in Ethiopia
(from field work described in this thesis), Mali, Niger, and Nigeria found that differences
between children who attend and do not attend school varies across survey settings in
regards to age, gender, having a clean face, and participation in antibiotic distribution for
trachoma control. Meta-analysis of the data found that TF was less likely (odds ratio=0.71)
among school-attendees than non-attendees when controlling for age, sex, and clustering at
the household and community levels. Children attending school did not represent the target
age group recommended for assessment of trachoma prevalence.
Stool specimens from 2,338 children aged 2-15 years from 99 communities in South
Gondar were assessed for intestinal parasites. The prevalence of any helminth infection was
24.2%, which represented a 50% reduction from a previously published study prior to the
SAFE interventions. Over 70% of children had at least one type of intestinal protozoan
infection. Significant increases were observed in household latrine ownership, access to
water, use of an improved water source for drinking, and face washing behaviour since the
start of the interventions.
Conclusions: Trachoma remains a public health problem in South Wollo and South Gondar
zones of the Amhara National Regional State of Ethiopia and ongoing interventions are
warranted to control transmission to prevent incident blinding disease and provide surgery
for prevalent and incident cases of trichiasis. The application of new WHO guidelines to
evaluate trachoma at the sub-district level was feasible, but required significant resources.
Electronic data capture facilitates the implementation of such large-scale impact evaluation
surveys for neglected tropical diseases allowing the results to be generated immediately with
as few mistakes as were made with paper-based data collection. Measuring prevalence of
TS among children over time offers an additional way to monitor impact of the SAFE
strategy. Children under the age of 11 years have substantially benefited from having lived in
an environment where the SAFE strategy has been implemented for five years. The use of
school-based sampling approaches for assessing trachoma prevalence risks
underestimating true prevalence in the community. The prevalence of intestinal helminths
among school-aged children has declined alongside significant increases in household-level
indicators of water, sanitation, and hygiene since the implementation of the SAFE strategy in
South Gondar. Yet, there is ongoing transmission of intestinal parasitic infections warranting
improved control interventions. Integrating both the assessment of trachoma and intestinal
parasitic infections in community-based surveys was a feasible approach to evaluate a
broader impact of the SAFE strategy in a programmatic setting. Overall, the operational
research presented in this thesis successfully generated evidence for health system
decisions, contributed new information to the respective scientific fields, and identified areas
warranting additional research
PACE-UP (Pedometer and consultation evaluation - UP) – a pedometer-based walking intervention with and without practice nurse support in primary care patients aged 45–75 years: study protocol for a randomised controlled trial
No full text© 2013 Harris et al.; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background - Most adults do not achieve the 150 minutes weekly of at least moderate intensity activity recommended for health. Adults’ most common physical activity (PA) is walking, light intensity if strolling, moderate if brisker. Pedometers can increase walking; however, most trials have been short-term, have combined pedometer and support effects, and have not reported PA intensity. This trial will investigate whether pedometers, with or without nurse support, can help less active 45–75 year olds to increase their PA over 12 months. Methods/design: Design: Primary care-based 3-arm randomized controlled trial with 12-month follow-up and health economic and qualitative evaluations. Participants: Less active 45–75 year olds (n = 993) will be recruited by post from six South West London general practices, maximum of two per household and households randomised into three groups. Step-count and time spent at different PA intensities will be assessed for 7 days at baseline, 3 and 12 months by accelerometer. Questionnaires and anthropometric assessments will be completed. Intervention: The pedometer-alone group will be posted a pedometer (Yamax Digi-Walker SW-200), handbook and diary detailing a 12-week pedometer-based walking programme, using targets from their baseline assessment. The pedometer-plus-support group will additionally receive three practice nurse PA consultations. The handbook, diary and consultations include behaviour change techniques (e.g., self-monitoring, goal-setting, relapse prevention planning). The control group will receive usual care.
Outcomes: Changes in average daily step-count (primary outcome), time spent sedentary and in at least moderate intensity PA weekly at 12 months, measured by accelerometry. Other outcomes include change in body mass index, body fat, self-reported PA, quality of life, mood and adverse events. Cost-effectiveness will be assessed by the incremental cost of the intervention to the National Health Service and incremental cost per change in step-count and per quality adjusted life year. Qualitative evaluations will explore reasons for trial non-participation and the interventions’ acceptability. Discussion- The PACE-UP trial will determine the effectiveness and cost-effectiveness of a pedometer-based walking intervention delivered by post or practice nurse to less active primary care patients aged 45–75 years old. Approaches to minimise bias and challenges anticipated in delivery will be discussed.This project was funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme (project number HTA 10/32/02) and will be published in full in Health Technology Assessment
Images out of water : aspects of the interpretation of Ancient maritime grafitti
No full textPictorial graffiti representing ships from prehistory, protohistory and the early medieval period are frequently examined by nautical historians and archaeologists seeking information about ancient ship technology. Examples of the academic discussion and interpretation of these images may be found from the nineteenth century to the present day, in a wide range of studies. Many of these works reflect their writers' casual, even disdainful attitudes to ancient graffiti. This may be seen in their approach to the information which these images appear to contain, which may concentrate, for example, on the certain aspects of particular subjects without reference to details in their immediate or wider contexts, which may have a bearing on the images' form and meaning. In a similar vein, other writers have interpreted ancient ship graffiti using concepts of art, such as the assumption of realism of depiction, which may be inappropriate to some early visual imagery. This thesis argues that ancient ship graffiti need a more detailed and systematic interpretation as both art and artefact before their contribution to nautical history may be more reliably evaluated. In order to explore the many challenges which these graffiti offer, a multi-disciplinary approach is used, to consider aspects of the relationship between formal art and graffiti, the psychology of image making, symbolism, the philosophy of interpretation, archaeology, and the social meaning of physical context. Following these theoretical discussions, five case studies from a number of different regional and chronological groups have been chosen to provide some examples of many of the issues which were considered. It is hoped that this study demonstrates that an approach to the interpretation of ancient ship graffiti which avoids a narrow concentration on nautical technology may reveal more of their potential as evidence, not only for the form and use of early ships, but also for other aspects of life in the past
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