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71.
Y. YOM-TOV  R. WILSON  AMOS AR 《Ibis》1986,128(1):1-8
The water budget of incubating Jackass Penguin eggs was studied on Marcus Island, South Africa, and complementary measurements were made in the laboratory. The mean ambient temperature was 16-5 "C and the mean humidity was 12-4 Torr (89% relative humidity). The temperature of incubated live and water-filled eggs ranged between 14oCand 37 oC. The mean calculated egg temperature was 34-9' C. The mean brood patch temperature was 37-1 oC, slightly lower than the cloacal temperature (37.8 oC). The mean brood patch area was about 38 cm2. The rate of water loss was 411 mg day-1. The total diffusive water loss during 37 days of incubation was, as predicted, 15-2% of the initial 100-3 g egg mass. The total pore number was 6245 per egg and the shell thickness was 577 fira. It is suggested that the eggshell parameters, incubation length and nesting behaviour are compensated in such a way that an egg-to-nest water vapour pressure difference lower than commonly found is sufficient to bring about the normal total water loss.  相似文献   
72.
Fatty acid components, in both the free and combined form of the intact tropical lichen Teloschistes flavicans, and its isolated photobiont and mycobiont, were analyzed by GC-MS of derived methyl esters. Its rDNA analysis confirmed that the isolated cultured symbionts belong to the genera Trebouxia and Teloschistes, respectively. The fatty acid composition of the lichen did not correspond to those found in the isolated symbionts, suggesting that the fatty acid metabolism is markedly influenced by the symbiosis. Differences in the fatty acid composition in the lichen were observed during the summer (27 degrees C), when the main fatty acids were saturated and in the winter (22 degrees C) when an increase of unsaturated fatty acids occurred. Similar differences of composition were also observed for the cultured mycobiont at different temperatures. The increase in the unsaturation level at low temperatures would maintain the membrane fluidity. Our results are the first on the fatty acids of a tropical lichen and suggest that it is sensitive to small temperature variations, which influences its saturated and unsaturated fatty acid composition.  相似文献   
73.
This study focused on the use of sound playbacks as acoustic deterrents to direct native potamodromous migratory species away from all kind of traps. The effects of two acoustic treatments, a repeated sine sweep up to 2 kHz (sweep-up stimulus) and an intermittent 140 Hz tone, were tested in three fish species native to Iberia: Salmo trutta, Pseudochondrostoma duriense and Luciobarbus bocagei. In contrast with S. trutta, the endemic cyprinids P. duriense and L. bocagei exhibited a strong repulse reaction to the frequency sweep-up sound. The 140 Hz stimulus did not seem to alter significantly the behaviour of any of the studied species. These results highlight the potential of acoustic stimuli as fish behavioural barriers and their application to in situ conservation measures of native Iberian fish populations, to protect them from hydropower dams. In addition, this study shows that acoustic deterrents can be used selectively on target species.  相似文献   
74.
The purpose of this study was to compare the acute effects of general, specific and combined warm-up (WU) on explosive performance. Healthy male (n = 10) subjects participated in six WU protocols in a crossover randomized study design. Protocols were: passive rest (PR; 15 min of passive rest), running (Run; 5 min of running at 70% of maximum heart rate), stretching (STR; 5 min of static stretching exercise), jumping [Jump; 5 min of jumping exercises – 3x8 countermovement jumps (CMJ) and 3x8 drop jumps from 60 cm (DJ60)], and combined (COM; protocols Run+STR+Jump combined). Immediately before and after each WU, subjects were assessed for explosive concentric-only (i.e. squat jump – SJ), slow stretch-shortening cycle (i.e. CMJ), fast stretch-shortening cycle (i.e. DJ60) and contact time (CT) muscle performance. PR significantly reduced SJ performance (p =0.007). Run increased SJ (p =0.0001) and CMJ (p =0.002). STR increased CMJ (p =0.048). Specific WU (i.e. Jump) increased SJ (p =0.001), CMJ (p =0.028) and DJ60 (p =0.006) performance. COM increased CMJ performance (p =0.006). Jump was superior in SJ performance vs. PR (p =0.001). Jump reduced (p =0.03) CT in DJ60. In conclusion, general, specific and combined WU increase slow stretch-shortening cycle (SSC) muscle performance, but only specific WU increases fast SSC muscle performance. Therefore, to increase fast SSC performance, specific fast SSC muscle actions must be included during the WU.  相似文献   
75.
Interactions with humans impact many aspects of behavior and ecology in nonhuman primates. Because of the complexities of the human–nonhuman primate interface, methods are needed to quantify the effects of anthropogenic interactions, including their intensity and differential impacts between nonhuman primate groups. Stable isotopes can be used to quickly and economically assess intergroup dietary variation, and provide a framework for the development of specific hypotheses about anthropogenic impact. This study uses stable carbon and nitrogen isotope analysis to examine intraspecific variation in diet between five groups of Barbary macaques, Macaca sylvanus, in the Upper Rock Nature Reserve, Gibraltar. Analysis of hair from 135 macaques showed significant differences in δ13C and δ15N values between a group with minimal tourist contact and groups that were main tourist attractions. Because we observed no overt physiological or substantial behavioral differences between the groups, feeding ecology is the most likely cause of any differences in stable isotope ratios. Haphazard provisioning by tourists and Gibraltarians is a likely source of dietary variation between groups. Stable isotope analysis and observational data facilitate a deeper understanding of the feeding ecology of the Barbary macaques relevant to the role of an anthropogenic ecology for the species.  相似文献   
76.
A 1,6-naphthyridine inhibitor of HIV-1 integrase has been discovered with excellent inhibitory activity in cells, good pharmacokinetics, and an excellent ability to inhibit virus with mutant enzyme.  相似文献   
77.
Araucaria araucana (Monkey Puzzle), a southern South American tree species of exceptional cultural and economic importance, is of conservation concern owing to extensive historical clearance and current human pressures. Random amplified polymorphic DNA (RAPD) markers were used to characterise genetic heterogeneity within and among 13 populations of this species from throughout its natural range. Extensive genetic variability was detected and partitioned by analysis of molecular variance, with the majority of variation existing within populations (87.2%), but significant differentiation was recorded among populations (12.8%). Estimates of Shannon's genetic diversity and percent polymorphism were relatively high for all populations and provide no evidence for a major reduction in genetic diversity from historical events, such as glaciation. All pairwise genetic distance values derived from analysis of molecular variance (Phi(ST)) were significant when individual pairs of populations were compared. Although populations are geographically divided into Chilean Coastal, Chilean Andes and Argentinean regions, this grouping explained only 1.77% of the total variation. Within Andean groups there was evidence of a trend of genetic distance with increasing latitude, and clustering of populations across the Andes, suggesting postglacial migration routes from multiple refugia. Implications of these results for the conservation and use of the genetic resource of this species are discussed.  相似文献   
78.
Psathyrostachys juncea (2n = 2x = 14, NN), a source of barley yellow dwarf (BYDV) virus resistance with tolerance to drought and salinity, has been successfully hybridized in its autotetraploid form (2n = 4x = 28, NNNN) as the pollen parent to durum wheat (Triticum turgidum L.). The 2n = 4x = 28 (ABNN) F1 hybrid has a mean meiotic metaphase-I configuration of 20.29 univalents + 0.29 ring bivalents + 3.36 rod bivalents + 0.14 trivalents. Spike length, internode length, glume awn length and lemma awn length, as well as the general spike morphology of the F1 hybrid, are intermediate with those of the two parents. Pollinating the ABNN F1 hybrid has given backcross (BC)-I derivatives of an amphiploid (AABBNN) that expresses limited self-fertility. BC-2 derivatives have been obtained from these plants. Direct transfers of useful genes from Ps. juncea to wheat would require substantial genetic manipulation strategies. Both conventional and novel methodologies, which may complement each other, and so facilitate reaching an agricultural objective end point, are addressed.  相似文献   
79.
Human tourists share space with, touch, feed, and otherwise interact with Macaca at multiple locations. Across Asia and stretching to Gibraltar and Northern Africa, macaques form a substantial tourist attraction as their ranges become increasingly coincident with human use zones. Residing in or as tourist attractions, macaques frequently generate economic benefits to local humans and compete with them for habitat and specific resources. In addition, health conflicts may emerge from increased overlap and interactions between humans and macaques. There is only a handful of studies on the impact, structure, context, and cultural ecology of macaque tourist sites. We provide a general overview of 2 macaque tourist sites, one in Padangtegal, Bali, Indonesia and one in Gibraltar. Qualitative assessment reveals variability in behavioral, ecological, economic, and politically relevant facets of macaque tourism. Specifically, differences in aggression during interactions, potential health dangers, economic factors, and local human perceptions between Padangtegal and Gibraltar suggest that qualitative assessments can assist in our construction of broader models and conceptualizations of the interaction context.  相似文献   
80.
A molecular graphics analysis of the features which prevent cytosolic malate dehydrogenase dimers from forming tetramers was evaluated by its success in predicting the synthesis of a version of the LDH framework which is a stable dimer. Surface residues responsible for malate dehydrogenases being dimers were revealed by superimposing the structures of two dimers of pig cytosolic malate dehydrogenase on one homologous tetramer of L-lactate dehydrogenase from Bacillus stearothermophilus. Four regions were identified as composing the P-axis dimer-dimer interface. Two regions of the dimer were surface loops that collided when built as a tetramer: a large loop (residues 203-207, KNOBI) and a small loop (residues 264-269, KNOBII), and these were candidates to explain the dimeric character of malate dehydrogenase. The analysis was tested by constructing a synthetic B. stearothermophilus lactate dehydrogenase (KNOBI) containing the large malate dehydrogenase loop (residues 203-207 being AYIKLQAKE, and extra four amino acids). The new construct was thermotolerant (90 degrees C) and enzymically active with kcat and KM (pyruvate) values similar to those of the wild-type enzyme. However, whereas the allosteric activator fructose 1,6-bisphosphate decreased KM 100 times for wild type, it had no influence on KNOBI. The molecular volumes of 1-120 microM concentrations of the construct were measured by time-resolved decay of tryptophan fluorescence anisotropy and by gel filtration. Both methods showed the molecular weight of wild type increased from dimer to tetramer with Kd about 20 microM dimer. KNOBI remained a dimer under these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
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