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71.
A neutral growth inhibitor, isolated from methanolic extracts of sunflower seedlings, was characterized by spectral data as caprolactam. Light-grown se 相似文献
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Summary Brink (1982) characterizes the distribution of standing crop of nectar for Delphinium nelsonii as bonanzablank, based on comparison with a Poisson. He then discusses possible effects of standing crop variability on pollinator foraging behavior. We disagree with the use of the Poisson and the resulting conclusions. The expected distribution should not be based on doling out random amounts of nectar to flowers, but based on random return times to flowers by pollinators (elapsed time=nectar accumulated). When this model is used, standing crop variance does not differ markedly from expectation. What differences do exist can be accounted for by variability in nectar production rates of individual plants. We also take issue with the use of the bonanza-blank terminology. As originally formulated this refers to nectar production differences within a plant rather than standing crop differences among plants. 相似文献
74.
Meylin partially purified from spinal cords of dysmyelinating mutant (shiverer) mice had almost three-fold the specific activity of 5′-nucleotidase found in the respective myelin fraction from normal mice. The specific activities of two other normally myelin-associated enzymes, 2′,3′-cyclic nucleotide-3′-phosphohydrolase and carbonic anhydrase, were only slightly higher in the myelin membranes from shiveres, compared to those from controls. In the mutants, the three enzymes probably occur in oligodendrocyte processes. Hhypothetically, the 5′-nucleotidase in the myelin sheath in shiverer and normal mice may be localized in specialized structures. 相似文献
75.
From the Silberberg Quarry, type locality of the Silberberg Formation (Martini &Ritzkowski 1968), some planktonic foraminifera are described:Globigerina officinalis Subbotina, Globigerina ouachitaensisHowe &Wallace,G. praebulloides leroyi Blow &Banner, G.praebulloides occlusa Blow &Banner which taxa are here suggested to form intergrading morphotypes within the range of variation of a population dominated byG. officinalis. In addition,G. cf.danvillensis Howe &Wallace is found. The planktonic fauna, together with some elements in the benthonic fauna, suggests a possible correlation with the Danville Landing Member of the Jackson Formation, Louisiana, traditionally ascribed to the Upper Eocene. There is some similarity with European Uppermost Eocene — Lower Oligocene faunas described by various authors. The Silberberg Formation was suggested to be a Neostratotype for the Latdorfian Stage of the Lower Oligocene byMartini &Ritzkowski (1968). It is suggested that the Silberberg Formation may well be coeval with the Upper Priabonian as proposed byCita 1969. 相似文献
76.
R Parrilla K Okawa K O Lindros U J Zimmerman K Kobayashi J R Williamson 《The Journal of biological chemistry》1974,249(15):4926-4933
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79.
Erik Peper 《Biological cybernetics》1970,7(3):107-112
Summary Experiments with feedback stimulation triggered from the subject's electroencephalogram result in changing the sequential time series of intervals of occipital alpha and intervals of little or no alpha EEG activity. The rate of recurrence of alpha and no-alpha EEG can be changed by regulating the external feedback stimuli or by asking the subject to change his internal state. Four different paradigms were investigated and the results interpreted in terms of the hypothesis that oculomotor functions regulate the occurrence and nonoccurrence of alpha.This work was supported by NIGMS Grants 5 PO1 GM 14940-04 and GM 15006-03.Most of this research was conducted at the Perception Laboratory, Veterans' Administration Hospital, Bedford, Massachusetts, with the cooperation of Dr. Thomas B. Mulholland. 相似文献
80.
Erik Schwarzbach 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1968,38(7):301-303
Zusammenfassung Die Schätzung der Varianzkomponenten bei Versuchen mit festen Variabilitätsursachen, z. B. bei der Prüfung von Sorten, Behandlungen usw., ist nur dann sinnvoll, wenn die Varianzkomponenten so definiert sind, daß ihre Summe der Gesamtvarianz gleich ist, d. h. daß sie sich additiv verhalten. Will man die so definierten Varianzkomponenten erwartungstreu schätzen, muß man die Überhöhung der mittleren Quadrate, die durch Division mit Freiheitsgraden statt mit der Gruppenzahl entstanden ist, wieder korrigieren. Diese Korrektion entfällt bei der Schätzung der Varianz von Zufallswirkungen.Die Erwartungswerte der mittleren Quadrate der üblichen varianzanalytischen Zerlegung und die erwartungstreuen Schätzungen der additiv definierten Varianzkomponenten werden am Beispiel eines Versuches mit zwei konstanten Variabilitätsursachen und einer Zufallseinwirkung dargelegt.
Estimating variance components in a fixed model of variance analysis
Summary The partition of a variance into components in experiments with fixed effects, i.e. experiments with varieties, treatment etc., is meaningful only if components are defined as additive parts of a whole. This also demands that the sum of the components of variance be equal to the total variance. Such additivity of the components of variance is achieved by appropriate definitions of the components of variance. Unbiassed estimates of the additively defined components of variance are obtained by a simple correction which eliminates the influence of degrees of freedom on the calculation of mean squares. This correction is not needed for the estimation of variances of random effects.The expected values of mean squares for the partition of variance and formulas for unbiassed estimates of additively defined components of variance are demonstrated in an experiment with two fixed effects and one random effect.相似文献