790 research outputs found
Uniplanar nystagmus associated with perceptual and cognitive visual dysfunction due to presumed focal ischemic occipital cortical atrophy: a missed diagnosis and new observation
Uniplanar nystagmus has been described in relation to pathology of the brain stem, retina, optic nerve, sensory visual deprivation, periventricular leucomalacia, and drug toxicity. This paper describes a case of uniplanar nystagmus associated with features of higher visual dysfunction and a presumed focal insult to the occipital lobes following an episode of neonatal apnea
Visual Perceptual Difficulties and Under-Achievement at School in a Large Community-Based Sample of Children
Difficulties with visual perception (VP) are often described in children with neurological or developmental problems. However, there are few data regarding the range of visual perceptual abilities in populations of normal children, or on the impact of these abilities on children's day-to-day functioning. Methods Data were obtained for 4512 participants in an ongoing birth cohort study (Avon Longitudinal Study of Parents and Children; ALSPAC). The children's mothers responded to questions designed to elicit indications of visual perceptual difficulties or immaturity, when their children were aged 13 years. We examined associations with standardised school test results in reading and in mathematics at age 1314 years (SATS-KS3), accounting for potential confounders including IQ. Results Three underlying factors explained half the variance in the VP question responses. These correlated best with questions on interpreting cluttered scenes; guidance of movement and face recognition. The adjusted parameter estimates (95% CI) for the cluttered-scenes factor (0.05; 0.02 to 0.08; p<0.001) suggested positive associations with the reading test results whilst that for the guidance-of-movement factor (0.03; 0.00 to 0.06; p = 0.026) suggested positive association with the mathematics results. The raw scores were associated with both test results. Discussion VP abilities were widely distributed in this sample of 13-year old children. Lower levels of VP function were associated with under-achievement in reading and in mathematics. Simple interventions can help children with VP difficulties, so research is needed into practicable, cost-effective strategies for identification and assessment, so that support can be targeted appropriately
Analysis of existing mathematics textbooks for use in secondary schools.
Thesis (Ed.M.)--Boston University
Thesis (M.A.)--Boston Universit
Off-axis digital flash photography: a common cause of artefact leukocoria in children.
Leukocoria, a presenting sign in several significant pediatric ocular conditions, can be artefactually produced by off-axis flash photography in healthy eyes. The authors demonstrate the conditions needed to produce this phenomenon, which is more commonly seen in children due to their larger-sized pupils, photogenicity, and frequent off-axis shots
Characterization of Shewanella oneidensis MtrC: a cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors
MtrC is a decaheme c-type cytochrome associated with the outer cell membrane of Fe(III)-respiring species of the Shewanella genus. It is proposed to play a role in anaerobic respiration by mediating electron transfer to extracellular mineral oxides that can serve as terminal electron acceptors. The present work presents the first spectropotentiometric and voltammetric characterization of MtrC, using protein purified from Shewanella oneidensis MR-1. Potentiometric titrations, monitored by UV–vis absorption and electron paramagnetic resonance (EPR) spectroscopy, reveal that the hemes within MtrC titrate over a broad potential range spanning between approximately +100 and approximately -500 mV (vs. the standard hydrogen electrode). Across this potential window the UV–vis absorption spectra are characteristic of low-spin c-type hemes and the EPR spectra reveal broad, complex features that suggest the presence of magnetically spin-coupled low-spin c-hemes. Non-catalytic protein film voltammetry of MtrC demonstrates reversible electrochemistry over a potential window similar to that disclosed spectroscopically. The voltammetry also allows definition of kinetic properties of MtrC in direct electron exchange with a solid electrode surface and during reduction of a model Fe(III) substrate. Taken together, the data provide quantitative information on the potential domain in which MtrC can operate
Indigenous family violence : an attempt to understand the problems and inform appropriate and effective responses to criminal justice system intervention
Whilst high levels of concern about the prevalence of family violence within Indigenous communities have long been expressed, progress in the development of evidence-based intervention programs for known perpetrators has been slow. This review of the literature aims to provide a resource for practitioners who work in this area, and a framework from within which culturally specific violence prevention programs can be developed and delivered. It is suggested that effective responses to Indigenous family violence need to be informed by culturally informed models of violence, and that significant work is needed to develop interventions that successfully manage the risk of perpetrators of family violence committing further offences.<br /
The Formation and Evolution of Virgo Cluster Galaxies - II. Stellar Populations
We use a combination of deep optical and near-infrared light profiles for a
morphologically diverse sample of Virgo cluster galaxies to study the
radially-resolved stellar populations of cluster galaxies over a wide range of
galaxy structure. We find that, in the median, the age gradients of Virgo
galaxies are either flat (lenticulars and Sa-Sb spirals) or positive
(ellipticals, Sbc+Sc spirals, gas-rich dwarfs, and irregulars), while all
galaxy types have a negative median metallicity gradient. Comparison of the
galaxy stellar population diagnostics (age, metallicity, and gradients thereof)
against structural and environmental parameters also reveals that the ages of
gas-rich systems depend mainly on their atomic gas deficiencies. Conversely,
the metallicities of Virgo gas-poor galaxies depend on their concentrations,
luminosities, and surface brightnesses. The stellar population gradients of all
Virgo galaxies exhibit no dependence on either their structure or environment.
We interpret these stellar population data for Virgo galaxies in the context of
popular formation and evolution scenarios, and suggest that gas-poor giants
grew hierarchically (through dissipative starbursts), gas-poor dwarfs have
descended from at least two different production channels (e.g., environmental
transformation and merging), while spirals formed inside-out, but with star
formation in the outskirts of a significant fraction of the population having
been quenched due to ram pressure stripping. (Abridged)Comment: 54 pages, 16 figures, 3 tables, re-submitted to MNRAS (edited to
reflect the referee's suggestions
Management and Clinical Outcome of Penetrating Keratoplasty for Long-Term Corneal Changes in Sympathetic Ophthalmia
Purpose. To report the visual outcome of penetrating keratoplasty performed on the sympathizing eye in three cases of sympathetic ophthalmitis. Methods. Interventional case series of three patients, diagnosed with sympathetic ophthalmitis, with corneal changes in the form of band keratopathy and decompensation underwent penetrating keratoplasty to the sympathizing eye. They had each sustained penetrating trauma as a child and had undergone previous cataract surgery and superficial keratectomy. Two patients had undergone lamellar keratoplasty prior to this procedure. One patient had undergone trabeculectomy for glaucoma, and she was on antiglaucoma medication. The preoperative visual acuity was 1/60 in the affected eye of each patient. Penetrating keratoplasty was performed in the sympathizing eye and the donor graft size was 7.50 mm, and the host graft size was 7.25 mm. Our patients were immunosuppressed prior to the procedure to help prevent graft rejection. Result. At one year follow-up, a BCVA of 6/36 or better was achieved in all three patients. Postoperative examination of the fundus showed peripheral chorioretinal atrophy with pigmentary changes at the macula, accounting for the limited vision. The grafts remain clear to date, and there has been no recurrence of uveitis or rejection. Conclusion. Penetrating keratoplasty can be considered as a surgical option to restore useful vision in a stable sympathizing eye in sympathetic ophthalmitis, and this depends on the extent of the pathology. However, these cases require treatment with immunosuppressives to prevent graft rejection and to prolong graft survival
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