1,259 research outputs found
Eye movements in mild traumatic brain injury: Ocular biomarkers
Mild traumatic brain injury (mTBI, or concussion), results from direct and indirect trauma to the head (i.e. a closed injury of transmitted forces), with or without loss of consciousness. The current method of diagnosis is largely based on symptom assessment and clinical history. There is an urgent need to identify an objective biomarker which can not only detect injury, but inform prognosis and recovery. Ocular motor impairment is argued to be ubiquitous across mTBI subtypes and may serve as a valuable clinical biomarker with the recent advent of more affordable and portable eye tracking technology. Many groups have positively correlated the degree of ocular motor impairment to symptom severity with a minority attempting to validate these findings with diffusion tract imaging and functional MRI. However, numerous methodological issues limit the interpretation of results, preventing any singular ocular biomarker from prevailing. This review will comprehensively describe the anatomical susceptibility, clinical measurement, and current eye tracking literature surrounding saccades, smooth pursuit, vestibulo-ocular reflex, vergence, pupillary light reflex, and accommodation in mTBI
Eye movements in mild traumatic brain injury: Clinical challenges
Mild traumatic brain injury (mTBI), also known as concussion, is a common injury which affects patients of all demographics. There is a global effort to accurately diagnose and identify patients at highest risk of prolonged symptom burden to facilitate appropriate rehabilitation efforts. Underreporting is common with large numbers not engaging with services, in addition to differences in treatment outcomes according to ethnicity, age, and gender. As patients recover, symptomology evolves which challenges rehabilitative efforts with no clear definition of ârecoveredâ. This review describes key areas in mTBI such as diagnostic challenges, epidemiology, prognosis, and pathophysiology which serves as an introduction to âEye Movements in Mild Traumatic Brain Injury: Ocular Biomarkers.
Post Operative Fungal Endopthalmitis Due to \u3cem\u3eGeotrichum candidum\u3c/em\u3e
Geotrichum species have been rarely reported as the cause of sepsis, disseminated infection in immunosuppressed patients. The patient we describe developed indolent endophthalmitis four months after her routine right eye cataract surgery. The intraoperative sample from right vitreous fluid grew Geotrichum candidum. The patient underwent vitrectomy, artificial lens explantation and intravitreal injection of amphotericin B followed by oral voriconazole. Despite these interventions, she underwent enucleation. This is the first published case of Geotrichum candidum endophthalmitis
Colony-stimulating factor-1 suppresses responses to CpG DNA and expression of toll-like receptor 9 but enhances responses to lipopolysaccharide in murine macrophages
Biochemical and genetic analysis of Ecm14, a conserved fungal pseudopeptidase
© 2020, The Author(s). Background: Like most major enzyme families, the M14 family of metallocarboxypeptidases (MCPs) contains a number of pseudoenzymes predicted to lack enzyme activity and with poorly characterized molecular function. The genome of the yeast Saccharomyces cerevisiae encodes one member of the M14 MCP family, a pseudoenzyme named Ecm14 proposed to function in the extracellular matrix. In order to better understand the function of such pseudoenzymes, we studied the structure and function of Ecm14 in S. cerevisiae. Results: A phylogenetic analysis of Ecm14 in fungi found it to be conserved throughout the ascomycete phylum, with a group of related pseudoenzymes found in basidiomycetes. To investigate the structure and function of this conserved protein, His6-tagged Ecm14 was overexpressed in Sf9 cells and purified. The prodomain of Ecm14 was cleaved in vivo and in vitro by endopeptidases, suggesting an activation mechanism; however, no activity was detectable using standard carboxypeptidase substrates. In order to determine the function of Ecm14 using an unbiased screen, we undertook a synthetic lethal assay. Upon screening approximately 27,000 yeast colonies, twenty-two putative synthetic lethal clones were identified. Further analysis showed many to be synthetic lethal with auxotrophic marker genes and requiring multiple mutations, suggesting that there are few, if any, single S. cerevisiae genes that present synthetic lethal interactions with ecm14Î. Conclusions: We show in this study that Ecm14, although lacking detectable enzyme activity, is a conserved carboxypeptidase-like protein that is secreted from cells and is processed to a mature form by the action of an endopeptidase. Our study and datasets from other recent large-scale screens suggest a role for Ecm14 in processes such as vesicle-mediated transport and aggregate invasion, a fungal process that has been selected against in modern laboratory strains of S. cerevisiae
Allocating conservation resources between areas where persistence of a species is uncertain
Research on the allocation of resources to manage threatened species typically assumes that the state of the system is completely observable; for example whether a species is present or not. The majority of this research has converged on modeling problems as Markov decision processes (MDP), which give an optimal strategy driven by the current state of the system being managed. However, the presence of threatened species in an area can be uncertain. Typically, resource allocation among multiple conservation areas has been based on the biggest expected benefit (return on investment) but fails to incorporate the risk of imperfect detection. We provide the first decision-making framework for confronting the trade-off between information and return on investment, and we illustrate the approach for populations of the Sumatran tiger (Panthera tigris sumatrae) in Kerinci Seblat National Park. The problem is posed as a partially observable Markov decision process (POMDP), which extends MDP to incorporate incomplete detection and allows decisions based on our confidence in particular states. POMDP has previously been used for making optimal management decisions for a single population of a threatened species. We extend this work by investigating two populations, enabling us to explore the importance of variation in expected return on investment between populations on how we should act. We compare the performance of optimal strategies derived assuming complete (MDP) and incomplete (POMDP) observability. We find that uncertainty about the presence of a species affects how we should act. Further, we show that assuming full knowledge of a species presence will deliver poorer strategic outcomes than if uncertainty about a species status is explicitly considered. MDP solutions perform up to 90% worse than the POMDP for highly cryptic species, and they only converge in performance when we are certain of observing the species during management: an unlikely scenario for many threatened species. This study illustrates an approach to allocating limited resources to threatened species where the conservation status of the species in different areas is uncertain. The results highlight the importance of including partial observability in future models of optimal species management when the species of concern is cryptic in nature
High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: Part 1, data analysis and results
High-resolution broadband spectroscopy at near-infrared wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar. Observations of stars were performed with the âTEDIâ interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec near-infrared echelle spectrograph. These are the first multidelay EDI demonstrations on starlight, as earlier measurements used a single delay or laboratory sources. We demonstrate very high (10Ă) resolution boost, from original 2700 to 27,000 with current set of delays (up to 3 cm), well beyond the classical limits enforced by the slit width and detector pixel Nyquist limit. Significantly, the EDI used with multiple delays rather than a single delay as used previously yields an order of magnitude or more improvement in the stability against native spectrograph point spread function (PSF) drifts along the dispersion direction. We observe a dramatic (20Ă) reduction in sensitivity to PSF shift using our standard processing. A recently realized method of further reducing the PSF shift sensitivity to zero is described theoretically and demonstrated in a simple simulation which produces a 350Ă times reduction. We demonstrate superb rejection of fixed pattern noise due to bad detector pixelsâEDI only responds to changes in pixel intensity synchronous to applied dithering. This part 1 describes data analysis, results, and instrument noise. A section on theoretical photon limited sensitivity is in a companion paper, part 2
Characterization of potential superspreader farms for bovine tuberculosis:A review
Background: Variation in host attributes that influence their contact rates and infectiousness can lead some individuals to make disproportionate contributions to the spread of infections. Understanding the roles of such âsuperspreadersâ can be crucial in deciding where to direct disease surveillance and controls to greatest effect. In the epidemiology of bovine tuberculosis (bTB) in Great Britain, it has been suggested that a minority of cattle farms or herds might make disproportionate contributions to the spread of Mycobacterium bovis, and hence might be considered âsuperspreader farmsâ.Objectives and Methods: We review the literature to identify the characteristics of farms that have the potential to contribute to exceptional values in the three main components of the farm reproductive number - Rf: contact rate, infectiousness and duration of infectiousness, and therefore might characterize potential superspreader farms for bovine tuberculosis in Great Britain.Results: Farms exhibit marked heterogeneity in contact rates arising from between-farm trading of cattle. A minority of farms act as trading hubs that greatly augment connections within cattle trading networks. Herd infectiousness might be increased by high within-herd transmission or the presence of supershedding individuals, or infectiousness might be prolonged due to undetected infections or by repeated local transmission, via wildlife or fomites.Conclusions: Targeting control methods on putative superspreader farms might yield disproportionate benefits in controlling endemic bovine tuberculosis in Great Britain. However, real-time identification of any such farms, and integration of controls with industry practices, present analytical, operational and policy challenges.<br/
Dynamic Responses of Calving Caribou to Oilfields in Northern Alaska
Past research has suggested that during the calving period, caribou (Rangifer tarandus) in Arctic Alaska generally avoid areas within 1 km of oilfield roads with traffic. However, avoidance is not absolute, and caribou may habituate to infrastructure (e.g., buildings, roads, well pads) and human activity. We conducted road-based surveys of caribou in oilfields on Alaskaâs Arctic Coastal Plain during the late calving and post-calving periods of June in 2000â02. We recorded location, composition, and behavior of caribou groups located less than 1 km from active gravel roads and production pads. Caribou groups with calves were on average distributed farther from oilfield infrastructure than were groups without calves, but habituation to oilfield activities, indicated by decreased avoidance, occurred at similar rates for groups with and without calves. During the calving period, sighting rates were greater in areas of low human activity, and calf percentages tended to be greater at night when oilfield activity was reduced. Caribou groups were on average closer to infrastructure during the post-calving periods than during the calving periods in 2000 and 2001, but not in 2002. In 2002, when snow melted early, caribou groups were closer to infrastructure during the calving period than in 2000 and 2001, when snow melted later, emphasizing the importance of examining environmental variables when investigating the dynamic interactions of caribou and oilfields. Overall, caribou appeared to habituate to active oilfield infrastructure after the calving period in 2000, late in the calving period in 2001, and likely before our sampling period in 2002. The timing of annual rehabituation was positively correlated with timing of spring snowmelt. Land and wildlife managers can use information from this study to develop calving period-specific mitigation measures that are more effective and flexible.Selon des recherches antĂ©rieures, pendant sa pĂ©riode de vĂȘlage, le caribou (Rangifer tarandus) de lâAlaska arctique Ă©vite gĂ©nĂ©ralement les rĂ©gions se trouvant Ă lâintĂ©rieur dâun kilomĂštre des routes oĂč circulent des vĂ©hicules menant aux chantiers pĂ©troliers. Cependant, cet Ă©vitement nâest pas absolu, et le caribou peut sâaccoutumer aux infrastructures (comme les bĂątiments, les routes et les chantiers) et Ă lâactivitĂ© humaine. Nous avons effectuĂ© le dĂ©nombrement des caribous prĂšs des routes des champs de pĂ©trole de la plaine cĂŽtiĂšre arctique de lâAlaska vers la fin de la pĂ©riode de vĂȘlage et aprĂšs la pĂ©riode de vĂȘlage de juin 2000 Ă 2002. Nous avons consignĂ© lâemplacement, la composition et le comportement des groupes de caribous se trouvant Ă moins dâun kilomĂštre des routes de gravier et des chantiers de production en activitĂ©. En moyenne, les caribous qui avaient des petits se tenaient plus loin des infrastructures pĂ©troliĂšres que les groupes de caribous qui nâavaient pas de petits. Cela dit, lâaccoutumance aux activitĂ©s pĂ©troliĂšres, dĂ©notĂ©e par un moins grand Ă©vitement, survenait Ă des taux semblables pour les groupes qui avaient des petits et les groupes qui nâen avaient pas. Pendant la pĂ©riode de vĂȘlage, les taux dâobservation de caribous Ă©taient plus Ă©levĂ©s dans les rĂ©gions oĂč il y avait peu dâactivitĂ© humaine, et les pourcentages de petits avaient tendance Ă ĂȘtre plus Ă©levĂ©s la nuit, lorsquâil y avait peu de va-et-vient aux chantiers. En moyenne, les groupes de caribous sâapprochaient plus des infrastructures pendant les pĂ©riodes suivant le vĂȘlage des annĂ©es 2000 et 2001, mais pas en 2002. En 2002, quand la neige a fondu plus tĂŽt que dâhabitude, les groupes de caribous sâapprochaient plus des infrastructures pendant la pĂ©riode de vĂȘlage quâen 2000 et 2001, lorsque la neige a fondu plus tard. Cela fait ressortir lâimportance de tenir compte des variables environnementales lorsque nous faisons des enquĂȘtes sur les interactions dynamiques entre les caribous et les champs de pĂ©trole. Dans lâensemble, les caribous semblaient sâaccoutumer aux infrastructures pĂ©troliĂšres en activitĂ© aprĂšs la pĂ©riode de vĂȘlage en 2000, puis vers la fin de la pĂ©riode de vĂȘlage en 2001, et vraisemblablement avant notre pĂ©riode dâĂ©chantillonnage en 2002. Le moment de lâaccoutumance annuelle coĂŻncidait positivement avec le moment de la fonte des neiges au printemps. Les gestionnaires des terres et de la faune peuvent se servir de lâinformation Ă©manant de cette Ă©tude pour Ă©laborer des mesures dâattĂ©nuation tenant compte de la pĂ©riode de vĂȘlage, mesures qui sont plus efficaces et qui prĂ©sentent plus de souplesse
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