315 research outputs found

    A case report of progressive Brown syndrome?

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    Aim: To report an unusual case of progressive Brown syndrome and the successful surgical treatment. Methods: A 42-year-old male with a documented 14-year history of progressive Brown syndrome is presented. To improve diplopia symptoms an ipsilateral superior oblique (SO) 7 mm silicone tendon spacer and a contralateral 3 mm superior rectus (SR) recession were performed. Results: The surgical procedure was successful in reducing the primary position deviation (preoperative 30ΔLHoT 7ΔLXT; one month post surgery 3ΔLHo; one year post surgery 7-8ΔLHo 1-2ΔE) and eliminating the abnormal head posture (AHP). Diplopia was only reported on elevation and depression following surgery. Conclusion: This case of Brown syndrome is unusual as it was progressive and had a documented history over a number of years prior to surgery. Surgical treatment of Brown syndrome is rarely required, but in this case was successful in improving the patient’s diplopia and AHP

    The provision of patient information about nystagmus

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    Aims: The aims of this study were to evaluate the current provision of patient information about nystagmus in orthoptic clinics in the UK and Ireland and to develop a standardised information pack about nystagmus. Methods: A questionnaire was circulated to orthoptists in the UK and Ireland asking whether they had information to provide to patients with nystagmus, what was included in this information and how it could be improved. Orthoptists were also asked what should be included in a standardised information pack about nystagmus. Results: Two hundred and thirty three orthoptists completed the questionnaire. One-third of responding orthoptists did not have information to provide to patients with nystagmus. Most reported the information available to them included details of support services and physical symptoms. Including information about living with nystagmus at different ages and long-term prognosis were the most common suggestions to improve information about nystagmus. More than half of orthoptists selected all the suggested topics to be included in a standardised information pack, with support services and long-term prognosis most frequently selected. Conclusions: Only 67% of responding orthoptists had information about nystagmus to give to patients or their families. Ways to improve the current information and content considered important by orthoptists were taken into account to create a nystagmus information pack, which is now available online

    Simulation of oscillopsia in virtual reality

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    Purpose: Nystagmus is characterised by involuntary eye movement. A proportion of those with nystagmus experience the world constantly in motion as their eyes move: a symptom known as oscillopsia. Individuals with oscillopsia can be incapacitated and often feel neglected due to limited treatment options. Effective communication of the condition is challenging and no tools to aid communication exist. This paper describes a virtual reality (VR) application that recreates the effects of oscillopsia, enabling others to appreciate the condition. Methods: Eye tracking data was incorporated into a VR oscillopsia simulator and released as a smartphone app – “Nystagmus Oscillopsia Sim VR”. When a smartphone is used in conjunction with a Google Cardboard headset, it presents an erratic image consistent with oscillopsia. The oscillopsia simulation was appraised by six participants for its representativeness. These individuals have nystagmus and had previously experienced oscillopsia but were not currently symptomatic; they were therefore uniquely placed to judge the app. The participants filled in a questionnaire to record impressions and the usefulness of the app. Results: The published app has been downloaded ~3700 times (28/02/2018) and received positive feedback from the nystagmus community. The validation study questionnaire scored the accuracy of the simulation an average of 7.8/10 while its ability to aid communication received 9.2/10. Conclusion: The evidence indicates that the simulation can effectively recreate the sensation of oscillopsia and facilitate effective communication of the symptoms associated with the condition. This has implications for communication of other visual conditions

    Evaluating the relationship between interannual variations in the Antarctic ozone hole and Southern Hemisphere surface climate in chemistry-climate models

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    Studies have recently reported statistically significant relationships between observed year-to-year spring Antarctic ozone variability and the Southern Hemisphere Annular Mode and surface temperatures in spring-summer. This study investigates whether current chemistry-climate models (CCMs) can capture these relationships, in particular, the connection between November total column ozone (TCO) and Australian summer surface temperatures, where years with anomalously high TCO over the Antarctic polar cap tend to be followed by warmer summers. The interannual ozone-temperature teleconnection is examined over the historical period in the observations and simulations from the Whole Atmosphere Community Climate Model (WACCM) and nine other models participating in the Chemistry-Climate Model Initiative (CCMI). There is a systematic difference between the WACCM experiments forced with prescribed observed sea surface temperatures (SSTs) and those with an interactive ocean. Strong correlations between TCO and Australian temperatures are only obtained for the uncoupled experiment, suggesting that the SSTs could be important for driving both variations in Australian temperatures and the ozone hole, with no causal link between the two. Other CCMI models also tend to capture this relationship with more fidelity when driven by observed SSTs, though additional research and targeted modelling experiments are required to determine causality and further explore the role of model biases and observational uncertainty. The results indicate that CCMs can reproduce the relationship between spring ozone and summer Australian climate reported in observational studies, suggesting that incorporating ozone variability could improve seasonal predictions, however more work is required to understand the difference between the coupled and uncoupled simulations

    Use of terrestrial field studies in the derivation of bioaccumulation potential of chemicals

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    Field-based studies are an essential component of research addressing the behavior of organic chemicals, and a unique line of evidence that can be used to assess bioaccumulation potential in chemical registration programs and aid in development of associated laboratory and modeling efforts. To aid scientific and regulatory discourse on the application of terrestrial field data in this manner, this article provides practical recommendations regarding the generation and interpretation of terrestrial field data. Currently, biota-to-soil-accumulation factors (BSAFs), biomagnification factors (BMFs), and bioaccumulation factors (BAFs) are the most suitable bioaccumulation metrics that are applicable to bioaccumulation assessment evaluations and able to be generated from terrestrial field studies with relatively low uncertainty. Biomagnification factors calculated from field-collected samples of terrestrial carnivores and their prey appear to be particularly robust indicators of bioaccumulation potential. The use of stable isotope ratios for quantification of trophic relationships in terrestrial ecosystems needs to be further developed to resolve uncertainties associated with the calculation of terrestrial trophic magnification factors (TMFs). Sampling efforts for terrestrial field studies should strive for efficiency, and advice on optimization of study sample sizes, practical considerations for obtaining samples, selection of tissues for analysis, and data interpretation is provided. Although there is still much to be learned regarding terrestrial bioaccumulation, these recommendations provide some initial guidance to the present application of terrestrial field data as a line of evidence in the assessment of chemical bioaccumulation potential and a resource to inform laboratory and modeling efforts

    Evaluating the relationship between interannual variations in the Antarctic ozone hole and Southern Hemisphere surface climate in chemistry-climate models

    Get PDF
    Studies have recently reported statistically significant relationships between observed year-to-year spring Antarctic ozone variability and the Southern Hemisphere Annular Mode and surface temperatures in spring-summer. This study investigates whether current chemistry-climate models (CCMs) can capture these relationships, in particular, the connection between November total column ozone (TCO) and Australian summer surface temperatures, where years with anomalously high TCO over the Antarctic polar cap tend to be followed by warmer summers. The interannual ozone-temperature teleconnection is examined over the historical period in the observations and simulations from the Whole Atmosphere Community Climate Model (WACCM) and nine other models participating in the Chemistry-Climate Model Initiative (CCMI). There is a systematic difference between the WACCM experiments forced with prescribed observed sea surface temperatures (SSTs) and those with an interactive ocean. Strong correlations between TCO and Australian temperatures are only obtained for the uncoupled experiment, suggesting that the SSTs could be important for driving both variations in Australian temperatures and the ozone hole, with no causal link between the two. Other CCMI models also tend to capture this relationship with more fidelity when driven by observed SSTs, though additional research and targeted modelling experiments are required to determine causality and further explore the role of model biases and observational uncertainty. The results indicate that CCMs can reproduce the relationship between spring ozone and summer Australian climate reported in observational studies, suggesting that incorporating ozone variability could improve seasonal predictions, however more work is required to understand the difference between the coupled and uncoupled simulations

    Academic freedom in Europe: time for a Magna Charta?

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    This paper is a preliminary attempt to establish a working definition of academic freedom for the European Union states. The paper details why such a definition is required for the European Union and then examines some of the difficulties of defining academic freedom. By drawing upon experience of the legal difficulties beset by the concept in the USA and building on previous analyses of constitutional and legislative protection for academic freedom, and of legal regulations concerning institutional governance and academic tenure, a working definition of academic freedom is then derived. The resultant definition which, it is suggested, could form the basis for a European Magna Charta Libertatis Academicae, goes beyond traditional discussions of academic freedom by specifying not only the rights inherent in the concept but also its accompanying duties, necessary limitations and safeguards. The paper concludes with proposals for how the definition might be tested and carried forward

    Climate-informed stochastic hydrological modeling: Incorporating decadal-scale variability using paleo data

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    A hierarchical framework for incorporating modes of climate variability into stochastic simulations of hydrological data is developed, termed the climate-informed multi-time scale stochastic (CIMSS) framework. A case study on two catchments in eastern Australia illustrates this framework. To develop an identifiable model characterizing long-term variability for the first level of the hierarchy, paleoclimate proxies, and instrumental indices describing the Interdecadal Pacific Oscillation (IPO) and the Pacific Decadal Oscillation (PDO) are analyzed. A new paleo IPO-PDO time series dating back 440 yr is produced, combining seven IPO-PDO paleo sources using an objective smoothing procedure to fit low-pass filters to individual records. The paleo data analysis indicates that wet/dry IPO-PDO states have a broad range of run lengths, with 90% between 3 and 33 yr and a mean of 15 yr. The Markov chain model, previously used to simulate oscillating wet/dry climate states, is found to underestimate the probability of wet/dry periods >5 yr, and is rejected in favor of a gamma distribution for simulating the run lengths of the wet/dry IPO-PDO states. For the second level of the hierarchy, a seasonal rainfall model is conditioned on the simulated IPO-PDO state. The model is able to replicate observed statistics such as seasonal and multiyear accumulated rainfall distributions and interannual autocorrelations. Mean seasonal rainfall in the IPO-PDO dry states is found to be 15%-28% lower than the wet state at the case study sites. In comparison, an annual lag-one autoregressive model is unable to adequately capture the observed rainfall distribution within separate IPO-PDO states. Copyright © 2011 by the American Geophysical Union.Benjamin J. Henley, Mark A. Thyer, George Kuczera and Stewart W. Frank

    “Making voices heard…”: Index on Censorship as Advocacy Journalism

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    The magazine Index on Censorship has sought, since its launch in 1972, to provide a space where censorship and abuses against freedom of expression have been identified, highlighted and challenged. Originally set up by a collection of writers and intellectuals who were concerned at the levels of state censorship and repression of artists in and under the influence of the Soviet Union and elsewhere, ‘Index’ has provided those championing the values of freedom of expression with a platform for highlighting human rights abuses, curtailment of civil liberties and formal and informal censorship globally. Charting its inception and development between 1971 and 1974, the paper is the first to situate the journal within the specific academic literature on activist media (Janowitz, 1975; Waisbord, 2009; Fisher, 2016). In doing so the paper advances an argument which draws on the drivers and motivations behind the publication’s launch to signal the development of a particular justification or ‘advocacy’ of a left-libertarian civic model of freedom of speech
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