4,173 research outputs found
Molecular epidemiology of African sleeping sickness
Human sleeping sickness in Africa, caused by Trypanosoma brucei spp. raises a number of questions. Despite the widespread distribution of the tsetse vectors and animal trypanosomiasis, human disease is only found in discrete foci which periodically give rise to epidemics followed by periods of endemicity A key to unravelling this puzzle is a detailed knowledge of the aetiological agents responsible for different patterns of disease--knowledge that is difficult to achieve using traditional microscopy. The science of molecular epidemiology has developed a range of tools which have enabled us to accurately identify taxonomic groups at all levels (species, subspecies, populations, strains and isolates). Using these tools, we can now investigate the genetic interactions within and between populations of Trypanosoma brucei and gain an understanding of the distinction between human- and nonhuman-infective subspecies. In this review, we discuss the development of these tools, their advantages and disadvantages and describe how they have been used to understand parasite genetic diversity, the origin of epidemics, the role of reservoir hosts and the population structure. Using the specific case of T.b. rhodesiense in Uganda, we illustrate how molecular epidemiology has enabled us to construct a more detailed understanding of the origins, generation and dynamics of sleeping sickness epidemics
Convection in the Earth's core driven by lateral variations in the core-mantle boundary heat flux
Moving core fluid maintains an isothermal core-mantle boundary (CMB), so lateral variations in the CMB heat flow result from mantle convection. Such variations will
drive thermal winds, even if the top of the core is stably stratified. These flows may contribute to the magnetic secular variation and are investigated here using a simple,
non-magnetic numerical model of the core. The results depend on the equatorial symmetry of the boundary heat flux variation. Large-scale equatorially symmetric
(ES) heat flux variations at the outer surface of a rapidly rotating spherical shell drive
deeply penetrating flows that are strongly suppressed in stratified fluid. Smaller-scale
ES heat flux variations drive flows less dominated by rotation and so less inhibited
by stratification. Equatorially anti-symmetric flux variations drive flows an order of
magnitude less energetic than those driven by ES patterns but, due to the nature of the Coriolis force, are less suppressed by stratification. The response of the rotating core fluid to a general CMB heat flow pattern will then depend strongly on the subadiabatic temperature profile. Imposing a lateral heat flux variation linearly related to a model of seismic tomography in the lowermost mantle drives flow in a density stratified fluid that
reproduces some features found in flows inverted from geomagnetic data
Insights from the revelations of divine love and the contemplation to attain love
Religious conversion, following Bernard Lonergan, is deeply mystical: "other worldly falling in love," "total, [unconditional] and permanent self-surrender." Julian of Norwich and Ignatius of Loyola both give, albeit in quite different language, an experiential and imagination rich accounts of religious conversion. For Julian, this is the "oneing" of the soul to God; for Ignatius, the contemplation which makes "beings in love.
Search for Antineutrino Charged Current Coherent Pion Production at SciBooNE
The SciBooNE experiment (Fermilab) recently published results of a search for
charged current coherent pion production in neutrino mode: muon neutrinos
scattering on carbon. The results of this study are that no evidence for
coherent pion production is observed, and SciBooNE set 90% confidence level
upper limits on the cross section ratio of charged current coherent pion
production to the total charged current cross section. Recently proposed new
coherent pion models predict a production of charged current coherent pion
events just below the SciBooNE's upper limit. Motivated by this, we performed a
search for charged current coherent pion production using SciBooNE's collected
antineutrino data since antineutrino data are expected to be more sensitive to
look at coherent pion production than neutrino data. This paper describes
preliminary results of a search for antineutrino charged current coherent pion
production at the SciBooNE experiment.Comment: 6 pages to be appeared in the proceedings for NuInt09 proceeding
Effects of wearing a mouth guard and movement complexity on simple reaction time
The purpose of the study was to determine how use of a mouth guard and movement complexity affect simple reaction time. The experiment consisted of three prescribed whole body movements of varying complexity. Participants were 12 college aged males who were free from injury and had some experience playing sports. Reaction time was determined using ground reaction force data and video data. A two-way analysis of variance with repeated measures on both factors revealed no significant mouth guard effect. A significant movement complexity effect resulted in longer reaction times for a high complexity movement than for low and moderate complexity movements. A significant interaction effect resulted in shorter reaction times on the low and moderate complexity movements when wearing a self-adapted mouth guard than when not wearing a mouth guard. Further research will be required to replicate the results of the current study and to apply them to practice
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