123 research outputs found

    Identities involving values of Bernstein, q-Bernoulli and q-Euler polynomials

    Full text link
    In this paper we give some relation involving values of q-Bernoulli, q-Euler and Bernstein polynomials. From these relations, we obtain some interesting identities on the q-Bernoulli, q-Euler and Bernstein polynomials.Comment: 12 page

    Ethnic Differences in Leaving Home: Timing and Pathways

    Get PDF
    The dynamics of leaving home for youth from migrant families in the Netherlands are examined using individual administrative data on the 1977 and 1983 birth cohorts for the period 1999–2004. A competing-risks approach is applied to distinguish leaving home for union formation, to live independently, and to share with others. Migrant youth, and particularly Turkish and Moroccan youth, leave home at a significantly younger age than Dutch youth, given the relevant background variables. This is remarkable, given the older ages at which young people in the origin countries leave the parental home. The result may be seen as evidence of how the potential effects of cultural norms are counter-affected by other factors, such as the facilities of the welfare state and the awkward position of migrant youth between two cultures. Considering the pathways out of home, the analysis largely confirms the expected pattern: Turkish and Moroccan youth leave home more often for union formation and particularly marriage, while this pathway is of minor importance for Dutch youth at early ages

    A novel formulation technology for baculoviruses protects biopesticide from degradation by ultraviolet radiation

    Get PDF
    Biopesticides are biological pest control agents that are viewed as safer alternatives to the synthetic chemicals that dominate the global insecticide market. A major constraint on the wider adoption of biopesticides is their susceptibility to the ultraviolet (UV: 290–400 nm) radiation in sunlight, which limits their persistence and efficacy. Here, we describe a novel formulation technology for biopesticides in which the active ingredient (baculovirus) is micro-encapsulated in an ENTOSTAT wax combined with a UV absorbant (titanium dioxide, TiO2). Importantly, this capsule protects the sensitive viral DNA from degrading in sunlight, but dissolves in the alkaline insect gut to release the virus, which then infects and kills the pest. We show, using simulated sunlight, in both laboratory bioassays and trials on cabbage and tomato plants, that this can extend the efficacy of the biopesticide well beyond the few hours of existing virus formulations, potentially increasing the spray interval and/or reducing the need for high application rates. The new formulation has a shelf-life at 30 °C of at least 6 months, which is comparable to standard commercial biopesticides and has no phytotoxic effect on the host plants. Taken together, these findings suggest that the new formulation technology could reduce the costs and increase the efficacy of baculovirus biopesticides, with the potential to make them commercially competitive alternatives to synthetic chemicals

    Linking Oviposition Site Choice to Offspring Fitness in Aedes aegypti: Consequences for Targeted Larval Control of Dengue Vectors

    Get PDF
    Controlling the mosquito Aedes aegypti, the predominant dengue vector, requires understanding the ecological and behavioral factors that influence population abundance. Females of several mosquito species are able to identify high-quality egg-laying sites, resulting in enhanced offspring development and survival, and ultimately promoting population growth. Here, the authors investigated egg-laying decisions of Ae. aegypti. Paradoxically, they found that larval survival and development were poorest in the containers females most often selected for egg deposition. Thus, egg-laying decisions may contribute to crowding of larvae and play a role in regulating mosquito populations. The authors also tested whether removal of the containers producing the most adult mosquitoes, a World Health Organization-recommended dengue prevention strategy, changes the pattern of how females allocate their eggs. Elimination of the most productive containers led to a more even distribution of eggs in one trial, but not another. These results suggest that behavioral adjustments by egg-laying females may lessen the effectiveness of a common mosquito control tactic. The authors advocate incorporating control strategies that take advantage of the natural egg-laying preferences of this vector species, such as luring egg-laying females to traps or places where their eggs will accumulate, but not develop
    • …
    corecore