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91.
Food consumption was measured in six female and seven male hand-raised marsh harrier (Circus aeruginosus) nestlings. Females consumed on average 4,321 g and males consumed 3,571 g of food during the nestling stage from 0 to 36 d. Total consumption until 56 d was 6,960 g and 5,822 g for females and males, respectively. On the basis of Fisher's sex ratio theory, this food intake ratio of 0.46 (intake male/[intake male + female]) would explain the observed male-biased fledging sex ratio of 55% males in marsh harrier broods. Growth, gross energy intake, and metabolizable energy intake were measured, along with metabolism of the nestlings, enabling us to determine energy allocation. The assimilation quotient (Q = 0.72) did not differ systematically between the sexes. Differences in metabolic rates between males and females at 15 and 30 d of age were fully attributable to the difference in body mass. Sexual size dimorphism in marsh harriers (female body mass around 60 d of age is 1.28 times greater than male mass) did not fully explain the difference in food intake between male and female nestlings: an analysis of energy requirements for growth and body mass in 16 avian species shows that energy intake was less than proportional to the average body mass at release. The data presented in this study are in agreement with Fisher's theory of inverse proportionality between the sex-specific ratios of energy requirements for growth and of offspring numbers in the marsh harrier population. 相似文献
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Gaertner Lowell; Sedikides Constantine; Vevea Jack L.; Iuzzini Jonathan 《Canadian Metallurgical Quarterly》2002,83(3):574
What is the primary motivational basis of self-definition? The authors meta-analytically assessed 3 hypotheses: (a) The individual self is motivationally primary, (b) the collective self is motivationally primary, and (c) neither self is inherently primary; instead, motivational primacy depends on which self becomes accessible through contextual features. Results identified the individual self as the primary motivational basis of self definition. People react more strongly to threat and enhancement of the individual than the collective self. Additionally, people more readily deny threatening information and more readily accept enhancing information when it pertains to the individual rather than the collective self, regardless of contextual influences. The individual self is the psychological home base, a stable system that can react flexibly to contextual influences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Analytical performance of the Tandem-R free PSA immunoassay measuring free prostate-specific antigen
DL Woodrum CM French TM Hill SJ Roman HL Slatore JL Shaffer LG York KL Eure KG Loveland GH Gasior PC Southwick LB Shamel 《Canadian Metallurgical Quarterly》1997,43(7):1203-1208
The analytical performance of the Tandem-R free PSA assay available from Hybritech Inc. was evaluated. Comparison of recoveries of purified free (unbound) prostate-specific antigen (PSA) diluted in female serum in the Tandem-R free PSA assay and the Tandem-R (total) PSA assay demonstrated a link in calibration between the assays and an accurate determination of percent free PSA. The cross-reactivity of the assay to purified PSA-alpha 1-antichymotrypsin was determined to be < 1%. The minimum-detectable concentration was < 0.05 microgram/L. The within-run and between-day CVs were < or = 5% for samples with > 0.3 microgram/L free PSA. Dilution and recovery showed no significant deviations from linearity across the assay range. The assay was insensitive to interference from blood components. The Tandem-R free PSA kit was shown to be an accurate, precise, and reliable assay for the measurement of free PSA. 相似文献
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An analysis of simultaneous variation in protein structures 总被引:5,自引:0,他引:5
Chelvanayagam G; Eggenschwiler A; Knecht L; Gonnet GH; Benner SA 《Protein engineering, design & selection : PEDS》1997,10(4):307-316
The simultaneous substitution of pairs of buried amino acid side chains
during divergent evolution has been examined in a set of protein families
with known crystal structures. A weak signal is found that shows that amino
acid pairs near in space in the folded structure preferentially undergo
substitution in a compensatory way. Three different physicochemical types
of covariation 'signals' were then examined separately, with consideration
given to the evolutionary distance at which different types of compensation
occur. Where the compensatory covariation tends towards retaining the
combined residue volumes, the signal is significant only at very low
evolutionary distances. Where the covariation compensates for changes in
the hydrogen bonding, the signal is strongest at intermediate evolutionary
distances. Covariations that compensate for charge variations appeared with
equal strength at all the evolutionary distances examined. A recipe is
suggested for using the weak covariation signal to assemble the predicted
secondary structural elements, where the evolutionary distance, covariation
type and weighting are considered together with the tertiary structural
context (interior or surface) of the residues being examined.
相似文献