11,600 research outputs found
Fabrication and characterisation of Er<sup>3+</sup>:Yb<sup>3+</sup> codoped phosphosilicate optical fibres for amplifiers and lasers
No full textSensitising erbium doped fibres with ytterbium significantly relaxes constraints in pump wavelength and device length. This makes versatile compact lasers and optical amplifiers operating at the important telecommunications window of 1.5µm a reality
Effects of Emitter Scaling and Device Biasing on Millimeter-Wave VCO Performance in 200 GHz SiGe HBT Technology
No full textPlatygaster hiemalis Forbes在抗性小麥品種對瘦蚊之寄生
No full textLaboratory studies were conducted to determine the effects of three wheat cultivars, “Knox 62” “CaldwelI” and “Monon”, on the Hessian fly Mayetiola destructor (Say) and its parasitoid Platygaster hiemalis Forbes. The number of Hessian flies that survived from egg to flaxseed stage, the number of Hessian flies parasitized by P. hiemalis, and the average number of parasitoids produced within each parasitized pupa were used to determine the cultivar and the interaction effects on the Hessian fly as well as on the parasitoid. The fewest Hessian fly survived, and the smallest parasitism was found on Knox 62 and were significantly different from those on other cultivars. Results showed that a cultivar with highly antibiosis against the Hessian fly could also reduce the effectiveness of this parasitoid. However, resistant cultivars and parasitoid complemented each other in reducing the numbers of the Hessian fly.
室內測定Knox 62、Caldwell及Monon三種小麥品種與寄生蜂Platyaster hiemalis Forbes及二者之交感作用對小麥癭蚊存活數、被寄生數及自被寄生癭蚊蛹羽化之P. hiemaIis蜂數等之影響，結果顯示Knox 62品種上，癭蚊之存活率與被寄生率均最低且與其他品種者差異顯著，此說明具高度抗生作用之小麥品種可減低瘦蚊密度但亦能影響該種蜂之寄生效果，雖然如此，一般而言，抗蟲小麥品種與P. hiemalis寄生蜂二者可相輔相成，合力降低小麥癭蚊之族群密度
Determination of Frequency and Distribution of Hessian Fly (Diptera: Cecidomyiidae) Biotypes in the Northeastern Soft Wheat Region
No full textFifteen collections of Hessian flies from the northern soft winter wheat region of the United States were used to determine the composition and frequency of biotypes. The wheat cultivars 'Seneca' (H7H8), 'Monon' (H-3), 'Knox 62' (H-6, H7H8), and 'Abe' (H-5) were used as differentials. Biotypes J and L replaced biotype B as the prevalent biotype in Indiana, since wheat cultivars having the H-5 and the H-6 genes have been grown. Biotype GP, the least virulent of any Hessian fly biotypes, was still present in New York indicating that wheat cultivars with no genes for resistance are still being grown there. The genetic variability of Hessian fly biotypes that enables them to overcome the resistance in wheat cultivars is discussed
Synaptic release rather than failure in the conditioning pulse results in paired-pulse facilitation during minimal synaptic stimulation in the rat hippocampal CA1 neurones
No full textIn this paper we report our observations of the relationship of paired-pulse facilitation (PPF) with synaptic release or release failure at small numbers of synaptic sites. Minimal stimulation protocols were employed to enable the activation of only one or a few axons which synapse onto CAI pyramidal cells in the hippocampus. Excitatory postsynaptic currents (EPSCs) in response to paired stimulation were measured. On the analysis of the data, we examined the effects of failure and synaptic release on PPF, and found that PPF was observed as a decrease in failures of synaptic release in response to test stimuli which were preceded by conditioning stimuli that evoked synaptic release. The test-pulse failure rate following conditioning pulse failures was indistinguishable from the overall conditioning pulse failure rate. It is postulated that the mechanism of paired-pulse facilitation is presynaptic and associated with successful synaptic release in response to the conditioning stimulus.<br/
Efficient cladding pumping of an Er<sup>3+ </sup>fibre
No full textWe report for the first time efficient operation of a cladding pumped Er3+ fibre configured in both fibre laser and fibre amplifier form. The fibre was of a double clad design compatible with beamshaped 980nm broadstripe pump lasers An efficiency in excess of 40% has been achieved
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