850 research outputs found
A Study Of The Effects Of Weekly Doses Of Niridazole On Schistosome Egg Output And Miricidial Hatching In A Patient Suffering From Bilharziasis
A CAJM article on "suppressive management" of bilharziasis.The concept of “suppressive management” in the control of bilharziasis has long been an attractive idea. If it were possible to administer a dose of a schistosomicidal drug once a week, particularly to children attending school, a significant reduction in egg output and an improvement in health would make the method worthy of careful consideration in bilharziasis control programmes
A Long-Term Study Of A Case Of Schistosoma Mansoni Subjected To Repeated Courses Of Treatment
A CAJM article on clinical testing and treatment for bilharziasis.The studies of the effects of treatment on individual patients suffering from bilharziasis has been a feature of the work of this Laboratory for some years (Blair et al. 1969b). From this work has emerged some interesting information on the disappearance and re-appearance of eggs and miracidia when treatment has failed. The earlier work was based on specimens of urine and stool passed by the patients from Monday to Friday only
Suppressive Therapy In The Control Of Bilharziasis: A Comparative Trial In African School Children
A CAJM article on the control of bilharzia-sis in Zimbabwean (Rhodesian) African children.One of the major problems facing the health service in any country which has a high prevalence of bilharziasis is the shortage of medical personnel required for the successful treatment of the large numbers of people who show infection. However, if a totally safe regime involving the administration of relatively innocuous drug at low dosages over long periods of time to control or suppress the level of infection in the person, the administration of the drug could then be left to the teachers or to other responsible members of the community. It is in this context that the policy of suppressive therapy or management of schistosome infections shows its greatest attraction
Confined granular packings: structure, stress, and forces
The structure and stresses of static granular packs in cylindrical containers
are studied using large-scale discrete element molecular dynamics simulations
in three dimensions. We generate packings by both pouring and sedimentation and
examine how the final state depends on the method of construction. The vertical
stress becomes depth-independent for deep piles and we compare these stress
depth-profiles to the classical Janssen theory. The majority of the tangential
forces for particle-wall contacts are found to be close to the Coulomb failure
criterion, in agreement with the theory of Janssen, while particle-particle
contacts in the bulk are far from the Coulomb criterion. In addition, we show
that a linear hydrostatic-like region at the top of the packings unexplained by
the Janssen theory arises because most of the particle-wall tangential forces
in this region are far from the Coulomb yield criterion. The distributions of
particle-particle and particle-wall contact forces exhibit
exponential-like decay at large forces in agreement with previous studies.Comment: 11 pages, 11 figures, submitted to PRE (v2) added new references,
fixed typo
Stress Transmission through Three-Dimensional Ordered Granular Arrays
We measure the local contact forces at both the top and bottom boundaries of
three-dimensional face-centered-cubic and hexagonal-close-packed granular
crystals in response to an external force applied to a small area at the top
surface. Depending on the crystal structure, we find markedly different results
which can be understood in terms of force balance considerations in the
specific geometry of the crystal. Small amounts of disorder are found to create
additional structure at both the top and bottom surfaces.Comment: 9 pages including 9 figures (many in color) submitted to PR
Detection methods for non-Gaussian gravitational wave stochastic backgrounds
We address the issue of finding an optimal detection method for a
discontinuous or intermittent gravitational wave stochastic background. Such a
signal might sound something like popcorn popping. We derive an appropriate
version of the maximum likelihood detection statistic, and compare its
performance to that of the standard cross-correlation statistic both
analytically and with Monte Carlo simulations. The maximum likelihood statistic
performs better than the cross-correlation statistic when the background is
sufficiently non-Gaussian. For both ground and space based detectors, this
results in a gain factor, ranging roughly from 1 to 3, in the minimum
gravitational-wave energy density necessary for detection, depending on the
duty cycle of the background. Our analysis is exploratory, as we assume that
the time structure of the events cannot be resolved, and we assume white,
Gaussian noise in two collocated, aligned detectors. Before this detection
method can be used in practice with real detector data, further work is
required to generalize our analysis to accommodate separated, misaligned
detectors with realistic, colored, non-Gaussian noise.Comment: 25 pages, 12 figures, submitted to physical review D, added revisions
in response to reviewers comment
Effect of boundaries on the force distributions in granular media
The effect of boundaries on the force distributions in granular media is
illustrated by simulations of 2D packings of frictionless, Hertzian spheres. To
elucidate discrepancies between experimental observations and theoretical
predictions, we distinguish between the weight distribution {\cal P} (w)
measured in experiments and analyzed in the q-model, and the distribution of
interparticle forces P(f). The latter one is robust, while {\cal P}(w) can be
obtained once the local packing geometry and P(f) are known. By manipulating
the (boundary) geometry, we show that {\cal P}(w) can be varied drastically.Comment: 4 pages, 4 figure
Automated mediator synthesis: combining behavioural and ontological reasoning
Software systems are increasingly composed of independently developed heterogeneous components. To ensure interoperability, mediators are needed that coordinate actions and translate exchanged messages between the components. We present a technique for automated synthesis of mediators, by means of a quotient operator, that is based on behavioural models of the components and an ontological model of the data domain. By not requiring a specification of the composed system, the method supports both off-line and run-time synthesis. The obtained mediator is the most general component that ensures freedom of both communication mismatches and deadlock in the composition. Validation of the approach is given by implementation of a prototype tool, while applicability is illustrated on heterogeneous holiday booking components
Statistics of the contact network in frictional and frictionless granular packings
Simulated granular packings with different particle friction coefficient mu
are examined. The distribution of the particle-particle and particle-wall
normal and tangential contact forces P(f) are computed and compared with
existing experimental data. Here f equivalent to F/F-bar is the contact force F
normalized by the average value F-bar. P(f) exhibits exponential-like decay at
large forces, a plateau/peak near f = 1, with additional features at forces
smaller than the average that depend on mu. Computations of the force-force
spatial distribution function and the contact point radial distribution
function indicate that correlations between forces are only weakly dependent on
friction and decay rapidly beyond approximately three particle diameters.
Distributions of the particle-particle contact angles show that the contact
network is not isotropic and only weakly dependent on friction. High
force-bearing structures, or force chains, do not play a dominant role in these
three dimensional, unloaded packings.Comment: 11 pages, 13 figures, submitted to PR
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