421 research outputs found

    Human Probing Behavior of Aedes aegypti when Infected with a Life-Shortening Strain of Wolbachia

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    Mosquitoes transmit diseases when they are actively searching for a source of blood. This so called probing behavior comprises the “searching” time, the beginning of the feeding process until the first sign of blood can be seen within the insect body. The manipulation of this behavior can have important consequences for the mosquito's ability to transmit pathogens, such as dengue virus or Plasmodium. In this study we examined the probing behavior of the main vector of dengue viruses, Aedes aegypti, when infected with an intracellular bacterium, Wolbachia pipientis. This bacterium alters the probing behavior of older mosquitoes such that they take longer to find a feeding site and longer to imbibe blood, which may make them more susceptible to human defense responses. The bacterium appears to reduce mosquito feeding success by preventing the mosquito from successfully inserting its stylet into human skin. The old age onset of reduced mosquito feeding success due to Wolbachia could selectively promote a reduction in dengue transmission

    Analysis of the Websites of Public Secondary Schools of Cantabria (Spain)

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    Resumen: Con la profunda transformación social que ha provocado la integración de las TIC en nuestro día a día, los modos de comunicación en el mundo educativo han evolucionado hacia internet y hacia un universo en red. Este hecho ha convertido a las páginas web de los centros educativos, entre otros elementos, en herramientas catalizadoras del panorama escolar. Con la finalidad de conocer la presentación de los contenidos de dichas páginas ante sus diferentes públicos se ha llevado a cabo en el presente trabajo una investigación para analizar las sedes web de los cuarenta y ocho centros públicos de Educación Secundaria de la Comunidad Autónoma de Cantabria. El análisis se ha llevado a cabo en relación a su contenido, organización, navegación, apariencia, diferenciación, velocidad, utilidad y accesibilidad. Los resultados obtenidos revelan cifras realmente alentadoras, como que sólo un 27?08% y 14?58% muestran deficiencias en su organización y claridad. Cabe destacar por otro lado, que la nota media de los sitios web en utilidad para las partes interesadas es de un 8?19 de valoración en su conjunto. Nos encontramos en líneas generales ante sitios webs con un claro carácter progresivo, activo e interactivo, aunque es posible concluir sugiriendo algunas mejoras como facilitar una difusión más rica de recursos útiles, así como suministrar una mayor exposición de los planes y proyectos más importantes del centro en algún apartado de las páginas web de los centros educativos.Abstract: With the profound social transformation that has led to the integration of ICT in our day to day, modes of communication in the educational world have evolved towards the Internet and towards a networked universe. This fact has turned the web pages of educational centers, among other elements, into catalytic tools for the school panorama. In order to know the presentation of the contents of these pages to their different audiences a research has been carried out in the present work to analyze the web sites of the forty-eight public secondary education centers of the Autonomous Community of Cantabria. The analysis has been carried out in relation to its content, organization, navigation, appearance, differentiation, speed, utility and accessibility. The results obtained reveal really encouraging figures, such as that only 27'08% and 14'58% show deficiencies in their organization and clarity. It should be noted on the other hand, that the average score of the websites in utility for the interested parties is of an 8'19 valuation as a whole. We are generally in front of websites with a clear progressive, active and interactive character, although it is possible to conclude by suggesting some improvements such as facilitating a richer dissemination of useful resources, as well as providing a greater exposure of the most important plans and projects of the center in some section of the web pages of educational centers

    A Virulent Wolbachia Infection Decreases the Viability of the Dengue Vector Aedes aegypti during Periods of Embryonic Quiescence

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    A new approach for dengue control has been proposed that relies on life-shortening strains of the obligate intracellular bacterium Wolbachia pipientis to modify mosquito population age structure and reduce pathogen transmission. Previously we reported the stable transinfection of the major dengue vector Aedes aegypti with a life-shortening Wolbachia strain (wMelPop-CLA) from the vinegar fly Drosophila melanogaster. Here, we report a further characterization of the phenotypic effects of this virulent Wolbachia infection on several life-history traits of Ae. aegypti. Minor costs of wMelPop-CLA infection for pre-imaginal survivorship, development and adult size were found. However, we discovered that the wMelPop-CLA infection dramatically decreased the viability of desiccated Ae. aegypti eggs over time. Similarly, the reproductive fitness of wMelPop-CLA infected Ae. aegypti females declined with age. These results reveal a general pattern associated with wMelPop-CLA induced pathogenesis in this mosquito species, where host fitness costs increase during aging of both immature and adult life-history stages. In addition to influencing the invasion dynamics of this particular Wolbachia strain, we suggest that the negative impact of wMelPop-CLA on embryonic quiescence may have applied utility as a tool to reduce mosquito population size in regions with pronounced dry seasons or in regions that experience cool winters

    The temporal reliability of serum estrogens, progesterone, gonadotropins, SHBG and urinary estrogen and progesterone metabolites in premenopausal women

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    BACKGROUND: There is little existing research to guide researchers in estimating the minimum number of measurement occasions required to obtain reliable estimates of serum estrogens, progesterone, gonadotropins, sex hormone-binding globulin (SHBG), and urinary estrogen and progesterone metabolites in premenopausal women. METHODS: Using data from a longitudinal study of 34 women with a mean age of 42.3 years (SD = 2.6), we calculated the minimum number of measurement occasions required to obtain reliable estimates of 12 analytes (8 in blood, 4 in urine). Five samples were obtained over 1 year: at baseline, and after 1, 3, 6, and 12 months. We also calculated the percent of true variance accounted for by a single measurement and intraclass correlation coefficients (ICC) between measurement occasions. RESULTS: Only 2 of the 12 analytes we examined, SHBG and estrone sulfate (E(1)S), could be adequately estimated by a single measurement using a minimum reliability standard of having the potential to account for 64% of true variance. Other analytes required from 2 to 12 occasions to account for 81% of the true variance, and 2 to 5 occasions to account for 64% of true variance. ICCs ranged from 0.33 for estradiol (E(2)) to 0.88 for SHBG. Percent of true variance accounted for by single measurements ranged from 29% for luteinizing hormone (LH) to 92% for SHBG. CONCLUSIONS: Experimental designs that take the natural variability of these analytes into account by obtaining measurements on a sufficient number of occasions will be rewarded with increased power and accuracy

    Acute effects of caffeine and cigarette smoking on ventricular long-axis function in healthy subjects

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    <p>Abstract</p> <p>Background</p> <p>Few data exist regarding the direct effects of caffeine and smoking on cardiac function. We sought to explore the acute effects of caffeine assumption, cigarette smoking, or both on left ventricular (LV) and right ventricular (RV) function in a population of young normal subjects.</p> <p>Methods</p> <p>Forty-five healthy subjects aged 25 ± 2 years underwent echocardiography. Fifteen of them were non-smokers and habitual coffee consumers (group 1), 15 were smokers and not habitual coffee consumers (group 2), and 15 were smokers and habitual coffee consumers (group 3). Peak systolic (S<sub>a</sub>), early diastolic E<sub>a</sub>, and late diastolic (A<sub>a</sub>) velocity of mitral annulus were measured by pulsed Tissue Doppler, and left atrioventricular plane displacement was determined by M-mode. Tricuspid annular velocities and systolic excursion (TAPSE) were also determined. Measurements were performed at baseline and after oral assumption of caffeine 100 mg in group 1, one cigarette smoking in group 2, and both in group 3.</p> <p>Results</p> <p>No changes in ventricular function were observed in group 1 after caffeine administration. In group 2, cigarette smoking yielded an acute increase in mitral A<sub>a </sub>(+12.1%, p = 0.0026), tricuspid S<sub>a </sub>(+9.8%, p = 0.012) and TAPSE (+7.9%, p = 0.017), and a decrease in the mitral E<sub>a</sub>/A<sub>a </sub>ratio (-8.5%, p = 0.0084). Sequential caffeine assumption and cigarette smoking in group 3 was associated with an acute increase in mitral A<sub>a </sub>(+13.0%, p = 0.015) and tricuspid A<sub>a </sub>(+11.6%, p < 0.0001) and a reduction in mitral E<sub>a</sub>/A<sub>a </sub>ratio (-8.5%, p = 0.0084) tricuspid E<sub>a </sub>(-6.6%, p = 0.048) and tricuspid E<sub>a</sub>/A<sub>a </sub>ratio (-9.6%, p = 0.0003). In a two-way ANOVA model controlling for hemodynamic confounding factors, changes in the overall population remained significant for mitral A<sub>a </sub>and E<sub>a</sub>/A<sub>a </sub>ratio, and for tricuspid A<sub>a </sub>and E<sub>a</sub>/A<sub>a </sub>ratio.</p> <p>Conclusion</p> <p>In young healthy subjects, one cigarette smoking is associated to an acute impairment in LV diastolic function and a hyperdynamic RV systolic response. Caffeine assumption alone does not exert any acute effect on ventricular long-axis function, but potentiates the negative effect of cigarette smoking by abolishing RV supernormal response and leading to a simultaneous impairment in both LV and RV diastolic function.</p
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