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  • SPACECRAFT PROPULSION AND POWER  (2)
  • Tephritidae  (2)
  • 1990-1994  (4)
  • 1
    ISSN: 1570-7458
    Keywords: Insecta ; foraging behavior ; host selection ; Tephritidae ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We observed the fruit foraging behavior of mature female oriental fruit flies,Dacus dorsalis Hendel (Diptera, Tephritidae), released individually onto potted field-caged host trees containing fruit of different quality, quantity, or type (no fruit, 3 or 12 uninfested kumquats, 12 infested kumquats, or 3 uninfested sweet oranges). Our findings were largely consistent with foraging-behavior theory, and with previous results for Mediterranean fruit fly,Ceratitis capitata (Wiedemann), and the apple maggot fly,Rhagoletis pomonella (Walsh): (1) flies left fruitless trees soon after release, (2) more flies visited fruit, and flies visited more fruit and spent more time on trees with increasing fruit density, and (3) Giving Up Time (time between last oviposition and leaving the tree) was significantly greater for flies visiting infested fruit than for those visiting uninfested fruit. Oriental fruit flies declined to oviposit in fruit containing conspecific larvae.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 100 (1994), S. 196-199 
    ISSN: 1432-1939
    Keywords: Braconidae ; Tephritidae ; Temporal ; Synchrony
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied an imported host-parasitoid community in Hawaii, asking to what extent the species covaried in a systematic fashion even though all species were exotic to Hawaii, and occurred in an artificial agroecosystem (a commercial guava, Psidium guajava L., orchard). Using knock-down pyrethrin sprays we were able to accurately quantify numbers of the host, [oriental fruit fly, Bactrocera dorsalis (Hendel)] and its four major parasitoid species [Biosteres arisanus (Sonan), Diachasmimorpha longicaudata (Ashmead), Psyttalia incisi (Silvestri), and Bi. vandenboschi (Fullaway)] at hourly intervals. We found that the parasitoids' activity and abundance was well correlated with the activity and abundance of their host, and that all four parasitoid species covaried in concert with one another. In fact, the magnitude of correlation between the different species in this system was greater than the correlation with temperature. This show clearly that an entirely exotic community, reassembled piecemeal as a result of biocontrol efforts, can end up with patterns of temporal covariation that are highly coincident. One other interesting result concerns the speed with which sprayed trees were recolonized by the fruit fly and its parasitoids. The time that it took each species to reach its mean density prior to removal by the first pyrethrin spray at 0600 hours varied. It took 2 h for female B. dorsalis to recolonize guava trees to pre-spray levels. It took 3 h for Bi. arisanus, 4 h for D. longicaudata, 7 h for Bi. vandenboschi and 14 h for P. incisi to reach pre-spray levels. The fact that Bi. arisanus recolonized vacant trees almost as rapidly as did the fruit fly pest suggest that there is little opportunity for the fruit fly to escape in space and time by “staying one step ahead of its enemies”.
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  • 3
    Publication Date: 2013-08-31
    Description: Heteroepitaxial InP solar cells, with GaAs substrates, were irradiated by 0.5 and 3 MeV protons and their performance, temperature dependency, and carrier removal rates determined as a function of fluence. The radiation resistance of the present cells was significantly greater than that of non-heteroepitaxial InP cells at both proton energies. A clear difference in the temperature dependency of V(sub oc), was observed between heteroepitaxial and homoepitaxial InP cells. The analytically predicted dependence of dV(sub oc)/dT on Voc was confirmed by the fluence dependence of these quantities. Carrier removal was observed to increase with decreasing proton energy. The results obtained for performance and temperature dependency were attributed to the high dislocation densities present in the heteroepitaxial cells while the energy dependence of carrier removal was attributed to the energy dependence of proton range.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Proceedings of the 12th Space Photovoltaic Research and Technology Conference (SPRAT 12); p 16-22
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  • 4
    Publication Date: 2013-08-31
    Description: The performance results of our most recently thermally diffused InP solar cells using the p(+)n (Cd,S) structures are presented. We have succeeded in fabricating cells with measured AMO, 25 C V(sub oc) exceeding 880 mV (bare cells) which to the best of our knowledge is higher than previously reported V(sub oc) values for any InP homojunction solar cells. The cells were fabricated by thinning the emitter, after Au-Zn front contacting, from its initial thickness of about 4.5 microns to about 0.6 microns. After thinning, the exposed surface of the emitter was passivated by a thin (approximately 50A) P-rich oxide. Based on the measured EQY and J(sub sc)-V(sub oc) characteristics of our experimental high V(sub oc) p(+)n InP solar cells, we project that reducing the emitter thickness to 0.3 microns, using an optimized AR coating, maintaining the surface hole concentration of 3 x 10(exp 18)cm(sup -3), reducing the grid shadowing from actual 10.55 percent to 6 percent and reducing the contact resistance will increase the actual measured 12.57 percent AMO 25 C efficiency to about 20.1 percent. By using our state-of-the-art p(+)n structures which have a surface hole concentration of 4 x 10(exp 18)cm(sup -3) and slightly improving the front surface passivation, an even higher practically achievable AMO, 25 C efficiency of 21.3 percent is projected.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Proceedings of the 12th Space Photovoltaic Research and Technology Conference (SPRAT 12); p 23-32
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