Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed $Q^2$-dependence is smooth. The measured ratio of H$(e,e'p)\gamma$ to H$(e,e'p)\pi^0$ cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest $W$ (1.8-1.9 GeV) show a striking $Q^2$- independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.

Emergence of phlebotomine sandflies (Diptera: Psychodidade) in non-flooded forest floor in Central Amazon, Brazil: a modified emergence trap model

Information concerning the potential natural breeding sites of phlebotomine sandflies are of high epidemiological importance. However, few studies have been conducted on the subject. This is due especially to the difficulties in finding as well as extracting immature sandflies that develop in the soil and organic matter of the forest floor. In the present study, a modified emergence trap model was tested in order to find potential breeding sites. This model was tested in the Pitinga Village, situated in the Presidente Figueredo municipality, in the State of Amazonas. Twenty-seven individuals belonging to nine species (Lutzomyia umbratilis,L. monstruosa,L. ayrozai,L. anduzei,L. trichopyga,L. davisi,L. geniculata,L. georgii e L. saulensis.) were collected. Lutzomyia umbratilis showed the highest number of individuals (37.1%) of all species captured in the area. The phlebotomine productivity was estimated as 2.2 sandflies per 100 m²/day. September showed the highest density of individuals, with a productivity of 5.8.Informações acerca de potenciais criadouros naturais de flebotomíneos sempre foram de fundamental interesse epidemiológico. Contudo, são poucas as informações advindas dos diversos estudos realizados até o momento. Isto se deve principalmente às dificuldades de localização e extração dos imaturos que se desenvolvem no solo e matéria orgânica do chão de florestas. No presente estudo o modelo modificado de armadilha de emergência foi testado na Vila do Pitinga, município de Presidente Figueiredo, Estado do Amazonas, a fim de localizar potenciais criadouros naturais. Vinte e sete indivíduos de nove espécies (Lutzomyia umbratilis,L. monstruosa,L. ayrozai,L. anduzei,L. trichopyga,L. davisi,L. geniculata,L. georgii e L. saulensis) foram coletados. Lutzomyia umbratilis foi a espécie com maior número de indivíduos, 10, representando 37,1% do total. A produção de flebotomíneos foi estimada em 2,2 flebotomíneos por 100 m² por dia. Em setembro, mês com maior número de indivíduos, esta produção foi de 5,8

Horizontal and vertical dispersal of dengue vector mosquitoes, Aedes aegypti and Aedes albopictus, in Singapore.

To study the dispersal of dengue vector mosquitoes in Singapore, females of Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae) were fed blood containing rubidium (Rb), which was detectable in their eggs by means of Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS). Laboratory calibration of the Rb reading, for a range of egg numbers from Rb-fed females, indicated a reasonably linear relationship and an unequivocal distinction between results with zero and one marked egg. Rb-marked female Aedes mosquitoes aged 3-5 days were released in semi-rural and urbanized parts of Singapore, with an array of ovitraps extending to a radius of 320 m from the release point. Subsequently, Rb-marked Aedes eggs were detected throughout the array, with similar distributions on each of the 4 days after release. More Rb was detected nearer the release point. However, when correction was made for the greater areas of zones further from the release point (and therefore presumably existence of more alternative oviposition sites), there were no significant differences in the numbers of marked eggs per ovitrap in the zones nearer or further from the release points. It is concluded that females of both these Aedes (Stegomyia) species could disperse easily and quickly throughout areas of radius 320 m in search of oviposition sites. This contrasts with the general belief that Ae. aegypti seldom flies more than 50 m and that control operations can safely be based on such an assumption. Releases on level 12 of a 21-storey apartment block, with ovitraps on each storey, showed similar easy and rapid dispersal to the top and bottom of the block