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41.
Johannes B Salnitzki VP Haller H Wilke D Fischer F Schlykova L 《Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology》1995,2(1):P107-P108
The relation between the results of laboratory tests and results of the interesting professional work is a very difficult one. The same is true for the relation between training and real performance. The pilot controlled MIR-docking manoeuvre is in reality a very seldom but very important one. The training of this manoeuvre is a very special professional work and only for cosmonauts available. But the objective estimation of the performance and the used objective and subjective needs is nevertheless necessary. Even for the subjective "stress"-feelings during task solving it is often impossible to get reliable data without any physiological measurements. The use of electrodes, cables and equipments is hardly limited during real work. Sometimes only the voice is available over more or less quality communication channels. So it is the case during the training and the real pilot controlled MIR-docking manoeuvre. Based on findings in the literature and own experiments analyzing the relation between fundamental voice frequency (F0) and subjective stress feelings we tested the hypothesis that a on-line measurement of F0 can be used for stress evaluation during standardised training sessions of MIR-docking manoeuvres. 相似文献
42.
Gerard Berger Guy Girault Jean-Michel Galmiche Stephane Pezennec 《Journal of bioenergetics and biomembranes》1994,26(3):335-346
The influences of total magnesium ion concentration at different total ATP concentrations, and of total ATP concentration, for different total magnesium ion concentrations, on the enzymatic rate of the isolated chloroplast F1 ATPase, have been followed by a chromatographic method consisting in the separation and determination of ADP. From the various series of curves, it is concluded that the experimental results (position of the maxima,K
m
values) are better fitted by a mechanism involving the activation of the enzyme by magnesium ion and hydrolysis of free ATP, rather than by the classical mechanism, for which the enzyme hydrolyzes the MgATP complex and is inhibited by Mg2+. Although the equations giving the reaction rate are similar in the two cases, the calculated values ofK
m
are widely different. The value obtained from the classical mechanism does not agree withK
D
, the dissociation constant of the enzyme-substrate complex, measured by the Hummel and Dreyer method. Moreover, when the total ATP concentration tends toward the total magnesium ion concentration, the nucleotide binding to the enzyme tends toward zero, although it should be maximum if MgATP were the true substrate. Finally, the inhibitory effect of Na+ is more easily explained as a competition between this ion and the activating Mg2+, than by the classical mechanism. 相似文献
43.
Evaluation of the role of State transitions in determining the efficiency of light utilisation for CO2 assimilation in leaves 总被引:2,自引:0,他引:2
Wheat leaves were exposed to light treatments that excite preferentially Photosystem I (PS I) or Photosystem II (PS II) and induce State 1 or State 2, respectively. Simultaneous measurements of CO2 assimilation, chlorophyll fluorescence and absorbance at 820 nm were used to estimate the quantum efficiencies of CO2 assimilation and PS II and PS I photochemistry during State transitions. State transitions were found to be associated with changes in the efficiency with which an absorbed photon is transferred to an open PS II reaction centre, but did not correlate with changes in the quantum efficiencies of PS II photochemistry or CO2 assimilation. Studies of the phosphorylation status of the light harvesting chlorophyll protein complex associated with PS II (LHC II) in wheat leaves and using chlorina mutants of barley which are deficient in this complex demonstrate that the changes in the effective antennae size of Photosystem II occurring during State transitions require LHC II and correlate with the phosphorylation status of LHC II. However, such correlations were not found in maize leaves. It is concluded that State transitions in C3 leaves are associated with phosphorylation-induced modifications of the PS II antennae, but these changes do not serve to optimise the use of light absorbed by the leaf for CO2 assimilation.Abbreviations Fm, Fo, Fv
maximal, minimal and variable fluorescence yields
- Fm, Fv
maximal and variable fluorescence yields in a light adapted state
- LHC II
light harvesting chlorophyll a/b protein complex associated with PS II
- qP
photochemical quenching
- A820
light-induced absorbance change at 820 nm
- PS I, PS II
relative quantum efficiencies of PS I and PS II photochemistry
- CO
2
quantum yield of CO2 assimilation 相似文献
44.
45.
Claude Bouchard Angelo Tremblay Jean-Pierre Desprs Germain Thriault Andr Nadeauf Paul J. Lupien Sital Moorjani Denis Prudhomme Guy Fournier 《Obesity (Silver Spring, Md.)》1994,2(5):400-410
Seven pairs of young adult male identical twins completed a negative energy balance protocol during which they exercised on cycle ergometers twice a day, 9 out of 10 days, over a period of 93 days while being kept on a constant daily energy and nutrient intake. The total energy deficit caused by exercise above the estimated energy cost of body weight maintenance reached 244 ± 9.8 MJ (Mean ± SEM). Baseline energy intake was estimated over a period of 17 days preceding the negative energy balance protocol. Mean body weight loss was 5.0 kg (SEM = 0.6) (p <0.001) and it was entirely accounted for by the loss of fat mass (p <0.001). Fat-free mass was unchanged. Body energy losses reached 191 MJ (SEM = 24) (p <0.001) which represented about 78% of the estimated energy deficit. Subcutaneous fat loss was slightly more pronounced on the trunk than on the limbs as estimated from skinfolds, circumferences, and computed tomography (CT). The reduction in CT-assessed abdominal visceral fat was quite striking, from 81 cm2 (SEM = 5) to 52 cm2 (SEM = 6) (p <0.001). At the same submaximal power output level, subjects oxidized more lipids than carbohydrates after the program as indicated by the changes in the respiratory exchange ratio (p <0.05). Intrapair resemblance was observed for the changes in body weight (p <0.05), fat mass (P <0.01), percent fat (p <0.01), body energy content (p <0.01), sum of 10 skinfolds (p <0.01), abdominal visceral fat (p <0.01), fasting plasma triglycerides (p <0.05) and cholesterol (p <0.05), maximal oxygen uptake (p <0.05), and respiratory exchange ratio during submaximal work (p <0.01). We conclude that even though there were large individual differences in response to the negative energy balance and exercise protocol, subjects with the same genotype were more alike in responses than subjects with different genotypes particularly for body fat, body energy, and abdominal visceral fat changes. High lipid oxidizers and low lipid oxidizers during sub-maximal exercise were also seen despite the fact that all subjects had experienced the same exercise and nutritional conditions for about three months. 相似文献
46.
47.
Species of Borrelia distinguished by restriction site polymorphisms in 16S rRNA genes 总被引:2,自引:0,他引:2
David Ralph Daniele Postic Guy Baranton Charles Pretzman Michael McClelland 《FEMS microbiology letters》1993,111(2-3):239-243
Abstract Three phyletic groups of Borrelia associated with Lyme disease, B. burgdorferi, B. garinii and group VS461 can be distinguished from each other and other species of Borrelia by Bfa I restriction site polymorphisms in PCR amplified 16S rRNA genes. One strain isolated from an Ixodes pacificus tick in California that was previously unclassifiable was distinguishable from B. burgdorferi by an Mnl I restriction site polymorphism. 相似文献
48.
49.
Colonies of the African stink ant Paltothyreus tarsatuslocated in the forest have nests with shorter horizontal galleries and a smaller total foraging surface than colonies located in open areas. Each solitary worker specializes on the same central or peripheral hunting zone but she does not specialize on a particular sector during group-retrieving. The search for prey is characterized by a wandering walk with spatial parameters varying in two ways. Capture of a termite releases a path characterized by sinuosity and a decrease in speed of movement. In contrast, a failure in the course of an attempted capture releases an increase in both sinuosity and speed of movement corresponding to a socalled reserve behavior. Each worker shortens her retrieving trip in comparison with her search trip and the straightness of the homing paths depends on the size and shape of the prey. Our data show that behavioral flexibility at the individual level in P. tarsatusis important in determining spatial foraging strategy at the colony level. 相似文献
50.
Le Maître Anne Guy Franck Merceron Gildas Kostopoulos Dimitris S. 《International journal of primatology》2023,44(1):209-236
International Journal of Primatology - Discoveries in recent decades indicate that the large papionin monkeys Paradolipopithecus and Procynocephalus are key members of the Late Pliocene –... 相似文献