45,157 research outputs found

    Field Tests of Kairomones to Increase Parasitism of Spruce Budworm (Lepidoptera: Tortricidae) Eggs by \u3ci\u3eTrichogramma\u3c/i\u3e Spp. (Hymenoptera: Trichogrammatidae)

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    Hexane extracts of spruce budworm, Choristoneura fumiferana, moth scales, applied at 0.04 moth-gram equivalents/branch and at 0.06 moth-gram equivalents/tree, failed to increase parasitism rates of Trichogramma spp. in two cutover spruce-fir stands in Maine. Releasing Maine-strain T. minutum apparently increased parasitism rates about 20-fold. However, application of kairomone extracts to whole branches and to upper crowns of small trees may have interfered with host-searching behaviors of Trichogramma parasitoids

    Electrical power system design for the US space station

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    The multipurpose, manned, permanent space station will be our next step toward utilization of space. A multikilowatt electrical power system will be critical to its success. The power systems for the space station manned core and platforms that have been selected in definition studies are described. The system selected for the platforms uses silicon arrays and Ni-H2 batteries. The power system for the manned core is a hybrid employing arrays and batteries identical to those on the platform along with solar dynamic modules using either Brayton or organic Rankine engines. The power system requirements, candidate technologies, and configurations that were considered, and the basis for selection, are discussed

    Perceived Family Life Quality in Junior Secondary School Students in Hong Kong

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The present longitudinal study examined perceived family functioning and related socio-demographic correlates from the perspective of adolescents in Hong Kong. Results showed that adolescent perceptions of family functioning based on different indicators gradually deteriorated over time. Regarding the socio-demographic correlates, (a) boys had more favourable perceived family functioning than did girls; (b) adolescents from non-intact families had poorer perceived family functioning than those from intact families; and (c) economically disadvantaged adolescents had poorer perceived family functioning than non-economically disadvantaged adolescents. Results also revealed that adolescents’ perceived family functioning was positively related to positive youth devel- opment. Analyses further indicated that perceived family functioning and positive youth development were concurrently and longitudinally related

    BEYOND GATEWAY CITIES: ECONOMIC RESTRUCTURING AND POVERTY AMONG MEXICAN IMMIGRANT FAMILIES AND CHILDREN

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    Our main objective is to better understand how new residential patterns have reshaped patterns of poverty among America's growing Mexican-origin population. We use data from the Integrated Public Use Microdata Samples (IPUMS) to document recent changes in poverty rates among native-born and foreign-born Mexicans living in the Southwest and in new regions where many Mexican families have resettled. Our analysis focuses on how changing patterns of employment (e.g., in construction and food processing industries) have altered the risk of poverty among Mexican families and children. We demonstrate that the Mexican population dispersed widely throughout the United States during the 1990s. Perhaps surprisingly, Mexican workers, especially new immigrants, had much lower rates of poverty in the new destination regions and rural areas than their counterparts that remained in traditional areas of population concentration - the Southwest. As we show in this study, the dispersion of America's Mexican native-born and immigrant populations raises questions and hopes about their economic and political incorporation into American society.Food Security and Poverty,

    Predation by Amphibians and Small Mammals on the Spruce Budworm (Lepidoptera: Tortricidae)

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    Stomach-content analyses of pitfall-trapped amphibians and small mammals showed that the eastern American toad, Bujo americanus americanus, and the wood frog, Rana sylvatica, preyed on late instars and moths of the spruce budworm, Choristoneura fumiferana. The spotted salamander, Ambystoma maculatum, and the masked shrew, Sorex cinereus, also preyed on late instars of the spruce budworm

    Competition between Electromagnetically Induced Transparency and Raman Processes

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    We present a theoretical formulation of competition among electromagnetically induced transparency (EIT) and Raman processes. The latter become important when the medium can no longer be considered to be dilute. Unlike the standard formulation of EIT, we consider all fields applied and generated as interacting with both the transitions of the Λ\Lambda scheme. We solve Maxwell equations for the net generated field using a fast-Fourier-transform technique and obtain predictions for the probe, control and Raman fields. We show how the intensity of the probe field is depleted at higher atomic number densities due to the build up of multiple Raman fields.Comment: 3.5 pages, 7 figure
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