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991.
Peter Schneider Manfred Hermes 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1976,106(1):39-49
The function of the flapping elytra was investigated in garden shafers (Melolontha melolontha L.) and rhinoceros beetles (Oryctes boas Fabr.).
相似文献
1. | The movements of alae and elytra are determined. Both move with the same frequency and in the same phase, but the range of the elytral stroke never reaches below the frontal plane. In downstroke the elytra are at an angle positive to the airstream (horizontal flight). |
2. | After exact investigation of the construction of the elytra (depth, width, length, surface, torsion and velocity of each point of the elytra) the most effective point in the production of lift during the downstroke was determined. |
3. | After loss of one third of the surface of the elytra the beetles cannot fly horizontally. In tethered flight the wing stroke frequency of the alae does not increase when the elytra are shortened. Shortening of the elytra does not interfere with the resonance system of the pterothorax. |
4. | The lift of the elytra results from active and passive components (more than 17% of the body weight). In the airstream (front 2.00 m/s, average body weight 944 mp) the passive lift is 14.3% for elytra in the down position; 3.1% of the lift is caused by the active downstroke. |
5. | The elytra of these beetles are indispensible for horizontal flight. Primarily they produce lift passively with added help from the downstroke, and have no function for the drag. The effect of upstroke is discussed. |
992.
993.
Results are presented which demonstrate that the molar flame-responses of partially methylated partially ethylated alditol acetates should be calculated on an effective carbon response (e.c.r.) basis. The relative responses of 2,3,4,6-tetra-O-ethyl-D-glucitol 1,5-diacetate, 2,3,6-tri-O-ethyl-D-glucitol 1,4,5-triacetate, hexa-O-ethyl-D-glucitol, hexa-O-methyl-D-glucitol, α-D-galactopyranose pentaacetate were measured and compared to the predicted values from three theories: equal molar response, equal weight response, effective carbon response. The observed values agree very well (±0?6%) with the e.c.r.-calculated values. The other theories of relative response can result in as much as 100% error in quantitation. The e.c.r-calculated relative response-factors for all commonly found partially methylated partially ethylated alditol acetates are presented, and their use is suggested for accurate quantitation. 相似文献
994.
Methyl 4,6-O-benzylidene-2,3-dideoxy-2-phenylazo-β-d-erythro-hex-2-enopyranoside has been synthesised, and its addition reactions with methoxide, azide, hydride, and deuteride ions have been studied. Comment is made on the stereochemistry of addition reactions of 2- and 3-phenylazo derivatives of methyl 4,6-O-benzylidene-2,3-dideoxy-d-hex-2-enopyranosides. 相似文献
995.
New data are presented on chromosome numbers for 36 species, two varieties, and two hybrids ofCirsium (Compositae). These include first reports forC. rhothophilum (2n = 34),C. andrewsii (2n = 32),C. crassicaule (2n = 32),C. quercetorum (2n= 32, 112),C. pascuarense (2n= 32),C. douglasii var.canescens (2n = 30, 34),C. hydrophilum (2n = 32),C. neomexicanum (2n = 30),C. cymosum (2n = 30, 34),C. acantholepis (2n= 34),C. radians (2n = 34), C.grahami (2n = 32),C. nigriceps (2n = 36),C. andersonii (2n= 32, 64),C. anartiolepis (2n = 34), andC. subcoriaceum (2n= 34). The published data on chromosome numbers of Eurasian and AmericanCirsium are summarized. In Eurasia, speciation has taken place primarily at the diploid level but is occasionally reinforced by polyploidy. The ancestral base number of 17 has been preserved in almost all species, and there is little evidence that reduction in chromosome number has played a significant role in speciation. In America speciation has proceeded exclusively at the diploid level, but the ancestral genome of 17 chromosomes has been retained in only about half of the species examined. In the remaining species, restructuring of the genome has occurred resulting in a reduction in number from 17 to 9 in extreme cases. Polyploidy, when seen, is of no significance. It is suggested that all species with greatly reduced numbers may represent products of a single reduction series. 相似文献
996.
Peter Goldblatt 《Brittonia》1975,27(4):373-385
The native bulbous Iridaceae of North America excluding Mexico comprise seven species in four genera. The type species ofAlophia Herb. (1836) is shown to belong toEustylis Engelm. & Gray (1836), hence the latter genus is reduced to synonymy. The well known genusAlophia (sensu auct. non Herb.) (Herbertia Sweet) now takes the nameTrifurcia. As a result of the new interpretation ofAlophia, new combinations are made for the North American and Latin American species ofTrifurcia andAlophia. New chromosome counts are given forNemastylis floridana (2n = 56) andTrifurcia lahue (2n = 56). 相似文献
997.
The temperature dependence of the binding of PhNapNH2 () to vesicles of egg phosphatidylcholine has been determined. The Arrhenius plot of the association constant exhibits a discontinuity at 20.9 °C, some 30 °C above the broad phase transition region of the phospholipid. In the temperature range above 20 °C, and ; in the temperature range below 20 °C, and These values are consistent with the view that there are well ordered lipid-lipid bonds below 20 °C which are significantly less important above this temperature. The order in the temperature range of 5 to 20 °C, though significantly greater than that above 20 °C, is still significantly less than that in the crystalline state. 相似文献
998.
When observed over a temperature range, erythrocyte membrane lipids undergo a transition at 18–20 °C (Zimmer, G. and Shirmer, H. (1974) Biochim. Biophys. Acta 345, 314–320). This observation has prompted an investigation of the effects that substrate binding has on the transition of the red cell membrane. Glucose and sorbose were compared, since transport kinetics of these sugars still pose unresolved questions.In membranes, preloaded with glucose, the break at the transition temperature was intensified, while it was abolished or reversed in membranes preloaded with sorbose.These results were corroborated using different solubilization procedures (sonication, sodium dodecyl sulfate treatment) of the membranes, and also different techniques (viscosimetry, 90° light scattering, 1-anilino-naphthalene-8-sulfonate fluorescence).In extracted membrane lipids, viscosimetry indicated a break at transition temperature after preloading with either glucose or sorbose.Disc electrophoresis revealed a different binding pattern of the two sugars.It is suggested, that the amplification of the discontinuity in red cell membranes by glucose and the abolition or reversal of the break by sorbose are mediated by membrane protein- and/or membrane lipid-protein interaction. 相似文献
999.
1000.