46 research outputs found
Dark States and Interferences in Cascade Transitions of Ultra-Cold Atoms in a Cavity
We examine the competition among one- and two-photon processes in an
ultra-cold, three-level atom undergoing cascade transitions as a result of its
interaction with a bimodal cavity. We show parameter domains where two-photon
transitions are dominant and also study the effect of two-photon emission on
the mazer action in the cavity. The two-photon emission leads to the loss of
detailed balance and therefore we obtain the photon statistics of the cavity
field by the numerical integration of the master equation. The photon
distribution in each cavity mode exhibits sub- and super- Poissonian behaviors
depending on the strength of atom-field coupling. The photon distribution
becomes identical to a Poisson distribution when the atom-field coupling
strengths of the modes are equal.Comment: 15 pages including 7 figures in Revtex, submitted to PR
Standard operating procedures for standardized mass rearing of the dengue and chikungunya vectors Aedes aegypti and Aedes albopictus (Diptera: Culicidae) - II - Egg storage and hatching
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Distribution of mosquitoes in the South East of Argentina and first report on the analysis based on 18S rDNA and COI sequences
Although Mar del Plata is the most important city on the Atlantic coast of Argentina, mosquitoes inhabiting such area are almost uncharacterized. To increase our knowledge in their distribution, we sampled specimens of natural populations. After the morphological identification based on taxonomic keys, sequences of DNA from small ribosomal subunit (18S rDNA) and cytochrome c oxidase I (COI) genes were obtained from native species and the phylogenetic analysis of these sequences were done. Fourteen species from the genera Uranotaenia, Culex, Ochlerotatus and Psorophora were found and identified. Our 18S rDNA and COI-based analysis indicates the relationships among groups at the supra-species level in concordance with mosquito taxonomy. The introduction and spread of vectors and diseases carried by them are not known in Mar del Plata, but some of the species found in this study were reported as pathogen vectors
Molecular and Behavioral Differentiation among Brazilian Populations of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae)
Lutzomyia longipalpis is the main vector of visceral leishmaniasis in the Americas. There is strong evidence that L. longipalpis is a species complex, but there is still no consensus regarding the number of species occurring in Brazil. We combined molecular and behavioral analyses of a number of L. longipalpis populations in order to help clarify this question. This approach has allowed us to identify two main groups of populations in Brazil. One group probably represents a single species distributed mainly throughout the coastal regions of North and Northeast Brazil and whose males produce the same type of copulation song and pheromone. The second group is more heterogeneous, probably represented by a number of incipient species with different levels of genetic divergence among the siblings that produce different combinations of copulation songs and pheromones. The high level of complexity observed raises important questions concerning the epidemiological consequences of this incipient speciation process
Accurate identification of Culicidae at aquatic developmental stages by MALDI-TOF MS profiling
Studies on populations of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in Brazil
Epidemiology of endemic Oropouche virus transmission in upper Amazonian Peru.
A cross-sectional serosurvey of a rural community near Iquitos, Peru was conducted to determine Oropouche (ORO) virus antibody prevalence and risk factors for human infection. Venous blood samples, and demographic, social, and risk factor data were obtained from people age five years of age and older who lived in the village of Santa Clara on the Nanay River, a tributary of the Amazon River. Sera were tested for ORO viral antibody by an ELISA. The specificity of viral antibody reactivity was determined by a standard plaque-reduction neutralization test. Interview data were analyzed by univariate and multiple logistic regression to determine which variables were statistically associated with previous ORO viral infection, as indicated by the presence of IgG antibody. Final models were evaluated based on log-likelihood and Wald chi-square. Clustering of seropositive residents within houses was analyzed by the method of Walter. Among 1,227 persons sampled, 33.7% (n=414) were positive for ORO viral IgG antibody. Overall, antibody prevalence was similar for males (33.9%) and females (33.6%), and increased significantly with age for both sexes to include more than half of persons more than 25 years of age. The length of residence in the village was positively associated with serologic status; persons who had moved to the village within the past 15 years were less likely to be seropositive than life-long residents of the same age. Antibody prevalence among immigrants who had lived in Santa Clara more than 15 years was similar to that in life-long residents. The activity most predictive of previous ORO viral infection was travel to forest communities and travel to Iquitos. No evidence of spatial heterogeneity in ORO virus antibody distribution was observed. Results suggested that endemic transmission of ORO virus in this region has been ongoing during many decades, and that people are at considerable risk of infection