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  • ENERGY PRODUCTION AND CONVERSION  (3)
  • Tephritidae  (2)
  • 1990-1994  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Temporal snychrony and patterns in an exotic host-parasitoid community (1994)
    Springer
    Oecologia 100 (1994), S. 196-199 
    Details
    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”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317147
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Intra-tree foraging behavior ofDacus dorsalis flies in relation to host fruit quantity, quality and type (1993)
    Springer
    Entomologia experimentalis et applicata 66 (1993), S. 13-20 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02381542
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  • 3
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    Performance, defect behavior and carrier enhancement in low energy, proton irradiated p+nn+ InP solar cells (1994)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The highest AMO efficiency (19.1 percent) InP solar cell consisted of an n+pp+ structure epitaxially grown on a p+ InP substrate. However, the high cost and relative fragility of InP served as motivation for research efforts directed at heteroepitaxial growth of InP on more viable substrates. The highest AMO efficiency (13.7 percent) for this type of cell was achieved using a GaAs substrate. Considering only cost and fracture toughness, Si would be the preferred substrate. The fact that Si is a donor in InP introduces complexities which are necessary in order to avoid the formation of an efficiency limiting counterdiode. One method used to overcome this problem lies in employing an n+p+ tunnel junction in contact with the cell's p region. A simpler method consists of using an n+ substrate and processing the cell in the p+ nn+ configuration. This eliminates the need for a tunnel junction. Unfortunately, the p/n configuration has received relatively little attention the best cell with this geometry having achieved an efficiency of 17 percent. Irradiation of these homoepitaxial cells, with 1 Mev electrons, showed that they were slightly more radiation resistant than diffused junction n/p cells. Additional p/n InP cells have been processed by some activity aimed at diffusion. Currently, there has been some activity aimed at producing heteroepitaxial p+nn+ InP cells using n+ Ge substrates. Since, like Si, Ge is an n-dopant in InP, use of this configuration obviates the need for a tunnel junction. Obviously, before attempting to process heteroepitaxial cells, one must produce a reasonably good homoepitaxial cell. In the present case we focus our attention on homoepitaxially on an n+ Ge substrate.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proceedings of the 13th Space Photovoltaic Research and Technology Conference (SPRAT 13); p 149-158
    Format: application/pdf
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  • 4
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    Electrochemical characterization of InP structures (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: Electrochemical (EC) techniques represent a simple and yet accurate method to characterize InP and related materials structures. With EC techniques, uncertainties in the measurements arising from factors such as surface effects, the composition and thickness of a front dead layer, the contacts, etc., can be significantly reduced when both a suitable electrolyte is used and the measuring conditions are carefully selected. In this work, the use of photoelectrochemical techniques with InP structures is reported. The work focuses on both the characterization and the optimization of structures grown by thermal diffusion and by epitaxial methods. Characterization of the structures is done by studying the variation in the density of surface states, number of defects, and net majority carrier concentration as a function of material removed. A step-by-step optimization process of n(sup +)p and p(sup+)n InP structures is also described. This involves the passivation and subsequent removal of damaged layers in order to extract the performance parameters of solar cells fabricated with these structures.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Twelfth Space Photovoltaic Research and Technology Conference (SPRAT 12); p 8
    Format: text
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  • 5
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    Progress in p(+)n InP solar cells fabricated by thermal diffusion (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: In SPRAT XI, we proposed that p(sup +)n diffused junction InP solar cells should exhibit a higher conversion efficiency than their n(sup +)p counterparts. This was mainly due to the fact that our p(sup +)n (Cd,S) cell structures consistently showed higher V (sub OC) values than our n(sup +)p (S,Cd) structures. The highest V(sub OC) obtained with the p(sup +)n (Cd,S) cell configuration was 860 mV, as compared to the highest V(sub OC) 840 mV obtained with the n(sup +)p (S,Cd) configuration (AMO, 25 C). In this work, we present the performance results of our most recent thermally diffused cells using the p(sup +)n (Cd,S) structure. We have been able to fabricate cells with V(sub OC) values approaching 880 mV. Our best cell with an unoptimized front contact grid design (GS greater than or equal to 10%) showed a conversion efficiency of 13.4% (AMO, 25 C) without an AR coating layer. The emitter surface was passivated by a -50A P rich oxide. Achievement of such high V(sub OC) values was primarily due to the fabrication of emitter surfaces, having EPD densities as low as 2E2 cm(sup -2) and N(sub a)N(sub d) of about 3E18 cm (sup -3). In addition, our preliminary investigation of p(sup +)n structures seem to suggest that Cd-doped emitter cells are more radiation resistant than Zn-doped emitter cells against both high energy electron and proton irradiation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Twelfth Space Photovoltaic Research and Technology Conference (SPRAT 12); p 7
    Format: text
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