A Comparative Study of the Spatial Distribution of Schistosomiasis in Mali in 1984–1989 and 2004–2006

Geostatistical maps are increasingly being used to plan neglected tropical disease control programmes. We investigated the spatial distribution of schistosomiasis in Mali prior to implementation of national donor-funded mass chemotherapy programmes using data from 1984–1989 and 2004–2006. The 2004–2006 dataset was collected after 10 years of schistosomiasis control followed by 12 years of no control. We found that national prevalence of Schistosoma haematobium and S. mansoni was not significantly different in 2004–2006 compared to 1984–1989 and that the spatial distribution of both infections was similar in both time periods, to the extent that models built on data from one time period could accurately predict the spatial distribution of prevalence of infection in the other time period. This has two main implications: that historic data can be used, in the first instance, to plan contemporary control programmes due to the stability of the spatial distribution of schistosomiasis; and that a decade of donor-funded mass distribution of praziquantel has had no discernable impact on the burden of schistosomiasis in subsequent generations of Malians, probably due to rapid reinfection

Triple Co-Administration of Ivermectin, Albendazole and Praziquantel in Zanzibar: A Safety Study

This paper describes how the use of three drugs which are used separately in mass drug distribution programmes when given together appear safe for use in large populations which have been previously treated with the same drugs separately (Mectizan [ivermectin], albendazole and praziquantel). The target diseases—lymphatic filariasis, soil-transmitted worms and schistosomiasis—were prevalent in Zanzibar up to 2000 but have been largely controlled by mass drug administration. The Ministry of Health and Social Welfare, with the support of WHO, initiated a small scale trial in a population of triple therapy in over 5,000 people initially in two sites, and having found there were no severe adverse events associated with the combined treatment then upscaled to treat the whole of the eligible population of over 700,000. Similarly, there were no severe adverse events. This is the first time the three drugs have been used together at the same time at scale in Africa and provide a basis for expansion of integrated preventive chemotherapy of helminths (worms). The next steps need to be initiated in populations which have heavier worm loads and such interventions need to be subject to close monitoring and ethical review

Iguasa's locl zeta functions of hypersurfaces with isolated singularities

IP 1241-05-111-97ARTICULOS EN REVISTA: Una introduccion elemental a la teoria de las funciones zeta locales de igusa / Victor;Albis, Wilson Zuñiga. -- En: lecturas Matematicas -- vol.20(1999); p. 5-3

Comparison of standard horizontal geophones and newly designed horizontal detectors

To increase the speed and efficiency of shallow seismic SH-wave data recording and to decrease acquisition costs, we have designed, constructed, and tested a new velocity tool that detects horizontal movements better than standard horizontal geophones. A comparative evaluation of significant characteristics and field performances of this new detector was conducted through laboratory and field tests on two sets of receivers: one consisting of 24 prototypes of the new detector and the other consisting of 24 standard horizontal geophones. Laboratory measurements revealed similar behaviors of impedance curves and geophone responses for the two types of detectors, but the impedance amplitudes and the frequency-response amplitudes of the new detector were twice those of the standard geophones. However, comparison of the horizontal-to-vertical (response) ratios, proved that the new detector better discriminates (6 dB on average) between the horizontal and vertical excitements. Field data proved that the energy, the maximum amplitude in the trace, and the maximum reflected amplitude were always higher in the data recorded with the new detector, although only half the source energy was used. The extra cost and weight of the new detector should be outweighed by its advantages, such as higher sensitivity to horizontal motions, better energy efficiency, and greater cost effectiveness. When a wavefield can be interpreted as SH-waves, SH-wave records can be acquired without the traditional drawbacks such as acquiring two records in each shot position, preprocessing of each record, and the final trace-to-trace subtraction needed to produce a pure SH-wave record