2,946 research outputs found
Toward Improving Interventions Against Toxoplasmosis by Identifying Routes of Transmission Using Sporozoite- specific Serological Tools
Background. Horizontal transmission of Toxoplasma gondii occurs primarily via ingestion of environmental oocysts or con- sumption of undercooked/raw meat containing cyst-stage bradyzoites. The relative importance of these 2 transmission routes remains unclear. Oocyst infection can be distinguished from bradyzoite infection by identification of immunoglobulin G (IgG) antibodies against T. gondii embryogenesis-related protein (TgERP). These antibodies are, however, thought to persist for only 6–8 months in human sera, limiting the use of TgERP serology to only those patients recently exposed to T. gondii. Yet recent sero- logical survey data indicate a more sustained persistence of anti-TgERP antibodies. Elucidating the duration of anti-TgERP IgG will help to determine whether TgERP serology has epidemiological utility for quantifying the relative importance of different routes of T. gondii transmission.
Methods. We developed a serocatalytic mathematical model to capture the change in seroprevalence of non-stage-specific IgG and anti-TgERP IgG antibodies with human age. The model was fitted to published datasets collected in an endemic region of Brazil to estimate the duration of anti-TgERP IgG antibodies, accounting for variable age–force of infection profiles and uncertainty in the diagnostic performance of TgERP serology.
Results. We found that anti-TgERP IgG persists for substantially longer than previously recognized, with estimates ranging from 8.3 to 41.1 years. The Brazilian datasets were consistent with oocysts being the predominant transmission route in these settings.
Conclusions. The longer than previously recognized duration of anti-TgERP antibodies indicates that anti-TgERP serology could be a useful tool for delineating T. gondii transmission routes in human populations. TgERP serology may therefore be an important epidemiological tool for informing the design of tailored, setting-specific public health information campaigns and interventions
Thirty Meter Telescope Site Testing I: Overview
As part of the conceptual and preliminary design processes of the Thirty
Meter Telescope (TMT), the TMT site testing team has spent the last five years
measuring the atmospheric properties of five candidate mountains in North and
South America with an unprecedented array of instrumentation. The site testing
period was preceded by several years of analyses selecting the five candidates,
Cerros Tolar, Armazones and Tolonchar in northern Chile; San Pedro Martir in
Baja California, Mexico and the 13 North (13N) site on Mauna Kea, Hawaii. Site
testing was concluded by the selection of two remaining sites for further
consideration, Armazones and Mauna Kea 13N. It showed that all five candidates
are excellent sites for an extremely large astronomical observatory and that
none of the sites stands out as the obvious and only logical choice based on
its combined properties. This is the first article in a series discussing the
TMT site testing project.Comment: Accepted for publication in PASP, April 2009 issu
Development of the Orion Crew Module Static Aerodynamic Database
This work describes the process of developing the nominal static aerodynamic coefficients and associated uncertainties for the Orion Crew Module for Mach 8 and below. The database was developed from wind tunnel test data and computational simulations of the smooth Crew Module geometry, with no asymmetries or protuberances. The database covers the full range of Reynolds numbers seen in both entry and ascent abort scenarios. The basic uncertainties were developed as functions of Mach number and total angle of attack from variations in the primary data as well as computations at lower Reynolds numbers, on the baseline geometry, and using different flow solvers. The resulting aerodynamic database represents the Crew Exploration Vehicle Aerosciences Project's best estimate of the nominal aerodynamics for the current Crew Module vehicle
Assessing capacity to engage in healthcare to improve the patient experience through health information technology
Patient engagement is viewed as a means to improve patient care, increase population health, and decrease health care costs. Efforts to improve engagement are prevalent across healthcare, particularly through health information technology (HIT) tools such as patient portals. However, we know that not all patients have the same ability to engage, leading to potential disparities. We present the Engagement Capacity Framework and suggest that examining capacity for engagement would improve our ability to address currently unmeasured factors that facilitate engagement. The objective was to examine factors that influence an individual’s capacity for engagement through HIT. We administered a paper survey to patients seen for care in a Family Medicine Clinic at a large Academic Medical Center, measuring potential components of the Engagement Capacity Framework. 142 patients completed the survey. Respondents reported high self-efficacy, high resilience, and good or better quality of life. Most were willing to use the Internet. Almost 30% of respondents did not use a patient portal and 37% of these respondents were very or somewhat unwilling to use a portal. We observed significant positive correlations (p \u3e 0.05) between portal use and searching for health information online, using email and owning technology. For those who did not use a portal we asked about willingness to use a portal; portal willingness was positively correlated with willingness to use the Internet (p \u3c 0.01). Our findings emphasize the importance of assessing capacity for engagement in order to target interventions to those most in need, connecting them to necessary resources to allow more full participation in their care.
Experience Framework
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Hydroclimatic Controls on the Means and Variability of Vegetation Phenology and Carbon Uptake
Long-term, global offline (land-only) simulations with a dynamic vegetation phenology model are used to examine the control of hydroclimate over vegetation-related quantities. First, with a control simulation, the model is shown to capture successfully (though with some bias) key observed relationships between hydroclimate and the spatial and temporal variations of phenological expression. In subsequent simulations, the model shows that: (i) the global spatial variation of seasonal phenological maxima is controlled mostly by hydroclimate, irrespective of distributions in vegetation type, (ii) the occurrence of high interannual moisture-related phenological variability in grassland areas is determined by hydroclimate rather than by the specific properties of grassland, and (iii) hydroclimatic means and variability have a corresponding impact on the spatial and temporal distributions of gross primary productivity (GPP)
Method for remotely powering a device such as a lunar rover
A method of supplying power to a device such as a lunar rover located on a planetary surface is provided. At least one, and preferably three, laser satellites are set in orbit around the planet. Each satellite contains a nuclear reactor for generating electrical power. This electrical power is converted into a laser beam which is passed through an amplifying array and directed toward the device such as a lunar rover. The received laser beam is then converted into electrical power for use by the device
Diversity and Keratin Degrading Ability of Fungi Isolated from Canadian Arctic Marine Bird Feathers
We present the first records of fungi associated with feathers from seabirds and sea ducks in the Canadian Arctic and sub-Arctic. Birds sampled in Nunavut and Newfoundland (Canada) included the Common Eider (Somateria mollissima), King Eider (S. spectabilis), Black-legged Kittiwake (Rissa tridactyla), Northern Fulmar (Fulmarus glacialis), Glaucous Gull (Larus hyperboreus), Black Guillemot (Cepphus grylle), and Thick-billed Murre (Uria lomvia). In total 19 fungal species were cultured from feathers, identified using ITS rDNA barcoding, and screened for their ability to degrade keratin using a keratin azure assay. Our results indicate that 1) of the 19 isolates, 74% were ascomycetes, while the remaining 26% were basidiomycetes (yeasts); 2) 21% of the ascomycete isolates demonstrated keratinolytic activity (a known pathogenicity factor for fungi that may potentially be harmful to birds); 3) the largest number of fungi were cultured from the sampled Thick-billed Murre; and 4) based on a multiple correspondence analysis, there is some indication that both the King Eider and the Thick-billed Murre collected in the low Arctic had distinct fungal communities that were different from each other and from the other birds sampled. Although our sample sizes were small, initial trends in point (4) do demonstrate that additional study is merited to assess whether the fungal community differences are influenced by variation in the known ecologies of the avian hosts and fungi identified.Nous présentons les premiers enregistrements de champignons se rapportant aux plumes d’oiseaux et de canards de mer dans l’Arctique et la région subarctique du Canada. Parmi les oiseaux échantillonnés au Nunavut et à Terre-Neuve (Canada), notons l’eider à duvet (Somateria mollissima), l’eider à tête grise (S. spectabilis), la mouette tridactyle (Rissa tridactyla), le fulmar boréal (Fulmarus glacialis), le goéland bourgmestre (Larus hyperboreus), le guillemot à miroir (Cepphus grylle) et le guillemot de Brünnich (Uria lomvia). En tout, 19 espèces de champignons ont été prélevées à partir de plumes. Elles ont été identifiées au moyen de codes à barres ITS ADNr et examinées afin de déterminer si elles sont capables de dégrader la kératine, et ce, à l’aide d’une épreuve de dégradation de la kératine au bleu azur. Nos résultats indiquent : 1) que parmi les 19 isolats, 74 % étaient des ascomycètes et que les 26 % restants étaient des basidiomycètes (levures); 2) que 21 % des isolats d’ascomycètes ont affiché une activité kératinolytique (un facteur de pathogénicité pour les champignons, facteur susceptible de nuire aux oiseaux); 3) que le plus grand nombre de cultures de champignons a été prélevé chez le guillemot de Brünnich; et 4) que d’après une analyse de correspondance multiple, il y a une certaine indication que les échantillons de l’eider à tête grise et du guillemot de Brünnich recueillis dans le Bas-Arctique comprenaient des communautés fongiques distinctes qui différaient les unes des autres ainsi que des autres oiseaux échantillonnés. Même si la taille de nos échantillons était petite, les premières tendances ressortant du point (4) démontrent qu’il y a lieu de faire des études plus poussées afin de déterminer si les différences entre les communautés fongiques sont influencées par la variation des écologies connues des hôtes aviaires et des champignons identifiés
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