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Scott A. Kleiner 《Biology & philosophy》1999,14(1):55-63
Thomas Nickles challenges my thesis that innovative discoveries can be based on deliberately chosen problems and research strategies. He suggests that all significant innovation can be seen as such only in retrospect and that its generation must be serendipitous. Here I argue in response that significant innovations can and do often arise from self conscious critical appraisal of orthodox practice combined with regulated though speculative abductive argumentation to alternative explanatory schemata. Orthodox practice is not based upon monolithic systems of belief about the subject of inquiry. Rather major domains of scientific practice often are approached from different conceptualizations that provide grounds for critical dialectic and consilient empirical information. Abductive arguments that meet appropriate conditions of likelihood, probability and analogy are an important means of justifying allocating resources to innovative practices that have yet to produce products that can rival those of established orthodoxy. 相似文献
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Francisco Gutirrez‐Corchero M. Victoria Arruga Lourdes Sanz Cristina García M. Angeles Hernndez Francisco Campos 《Molecular ecology resources》2002,2(1):75-77
FTA® cards were used for long‐term storage of avian blood samples. Blood DNA was extracted by a simple method and used in PCR for sex identification of adult and nestling Great Grey Shrikes Lanius excubitor. 相似文献
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QIAN‐WAN MENG YI‐BO LUO 《Botanical journal of the Linnean Society. Linnean Society of London》2008,158(4):689-695
A new species, Galearis huanglongensis Q.W.Meng & Y.B.Luo, is described and illustrated. It is similar to Galearis cyclochila (Franch. & Sav.) Soó and Galearis diantha (Schltr.) P.F.Hunt, but differs in having a short spur, two elliptical lateral stigma lobes and distinctly separated bursicles. This new species is known only from the type locality, the Huanglong Valley, Songpan County, western Sichuan, China, growing amongst mosses under alpine shrubs at an elevation of about 3000 m. Based on two years of observations of its population size, the species was categorized as critically endangered CR (B1a, B2a) according to the World Conservation Union (IUCN) Red List Categories and Criteria, Version 3.1. The micromorphology of pollinia and seeds was observed by scanning electron microscopy and compared with that of G. cyclochila and G. diantha. The results supported G. huanglongensis Q.W.Meng & Y.B.Luo as a new species. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 689–695. 相似文献
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Dependence of cytoplasmic calcium transients on the membrane potential in isolated nerve endings of the guinea pig 总被引:5,自引:0,他引:5
The relation of changes in internal, free Ca2+, measured with arsenazo III, to the membrane potential, measured with the cyanine dye di-S-C2(5) or 86Rb+ distribution ratio, was studied in isolated guinea pig cortical nerve endings. Depolarization of the plasma membrane with veratridine or gramicidin as well as addition of ionophore A23187 led to an increase in cytosolic Ca2+. Only the response to veratridine was inhibited by tetrodotoxin. The dependence of the depolarization-induced increase in intraterminal, free Ca2+ on the membrane potential between about -50 to 0 mV was sigmoidal. A maximal increase in cytosolic Ca2+ was reached when the membrane potential was depolarized from the resting level, about -64 mV, to about -40 mV. These results show that in isolated nerve endings the activation of voltage-sensitive Ca2+ channels concomitantly leads to an increase in cytosolic, free Ca2+. Comparison of the results of the present study with the previous electrophysiological observations indicate that Ca2+ channels in synaptosomes, presynaptic nerve terminals of the squid giant synapse and cardiac cells have essentially similar voltage dependency. 相似文献
38.
Three acetotrophicMethanosarcina species, which included marine, nonmarine, and thermophilic strains, were grown on acetate in a 10-liter pH auxostat. Specific growth rates and molar growth yields were constant throughout growth. Cell yields were up to 18-fold greater than previously reported. These properties of the pH auxostat indicate that it is a preferred culture method for the biochemical study of methanogenesis from acetate. 相似文献
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Benjamin Dickerman James Metzger W. Theodore Lee 《World journal of microbiology & biotechnology》2006,22(1):29-33
Summary Bacteria from recreational waters collected from two Lake Erie beaches in Dunkirk, New York were plated onto m Endo LES media.
The 16S rRNA gene was then amplified from coliform and non-coliform bacteria using the polymerase chain reaction. The PCR
products were characterized by restriction fragment length polymorphism (RFLP) analysis. A total of 8 RFLP groups were identified
from the analysis of 920 samples and selected PCR products from each group were sequenced. The DNA sequence analysis indicated
that more than half of the bacteria identified as coliforms on the m Endo plates belonged to the genus Aeromonas from the family Aeromonadaceae. Most of the remaining coliforms were from the Enterobacteriaceae. The data indicate that m Endo agar plates allow the growth of non-coliform bacteria, especially Aeromonas species. 相似文献
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