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This paper analyzes the interaction between science, philosophy and politics (including ideology) in the early work of J. B. S. Haldane (from 1922 to 1937). This period is particularly important, not only because it is the period of Haldane's most significant biological work (both in biochemistry and genetics), but also because it is during this period that his philosophical and political views underwent their most significant transformation. His philosophical stance first changed from a radical organicism to a position far more compatible with mechanical materialism. The primary intellectual influence that was responsible for this shift was that of F. G. Hopkins. Later, Haldane came to accept Marxism and its official metaphysics, dialectical materialism, a move that let him accept the materialist conception of the world while still maintaining a resolute distance from mechanism. Throughout all these changes, what is most obvious is the influence of science on Haldane's philosophical views. An influence in the opposite direction is far less apparent.Parts of this paper are extracted from a longer work which concerns the interactions between philosophy and science throughout Haldane's scientific career (Sarkar forthcoming). The general conclusions reached here, from a consideration of Haldane's work only from 1922 to 1937 (see Section 6), remain the same for the rest of his life, as is detailed in the longer work. Thanks are due to R. S. Cohen, J. F. Crow, A. R. Fersht, J. Maynard Smith, R. C. Olby, D. Paul, M. Ruse, J. Stachel and S. Sturdy for helpful discussions and comments and criticism of the positions outlined in this paper. This is Contribution No. BTBG-92-4 from the Theoretical Biology Group, Boston University.  相似文献   

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-Glucosidase and -xylosidase production by a yeastlike Aureobasidium sp. was carried out during solid-state and submerged fermentation using different carbon sources and crude enzymes were characterized. -Glucosidase and -xylosidase exhibited optimum activities at pH 2.0–2.5 and 3.0, respectively. These enzymes had the maximum activities at 65°C and were stable in a wide pH range and at high temperatures.  相似文献   

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The stoichiometries and stability constants of the proton, cobalt(II), nickel(II), copper(II) and zinc(II) complexes of 1-aminoethanephosphonic acid (α-Ala-P), 2-aminoethanephosphonic acid (β-Ala-P), 1-amino-2-phenylethanephosphonic acid (Phe-P) and 1 -amino-2-(4-hydroxyphenyl)ethanephosphonic acid (Tyr-P) have been determined pH-metrically at 25 °C and at an ionic strength of 0.2 mol dm 3 (KCl).From these data and the spectral parameters of the complexes it has been established that these simple aminophosphonic acids coordinate similarly to aminocarboxylic acids, forming chelate complexes MA and MA2. However an MAH species with only phosphonate group coordination also exist at low pH. The differences between the complex-forming properties of aminophosphonates and aminocarboxylates have been explained by the differences in basicity, charge and size of the −PO32−and −COO groups.  相似文献   

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Responses of caryopsis germination, seedling emergence, and development of Agropyron cristatum (L.) Gaertn. (Gramineae) and Bromus inermis Leyss. (Gramineae), two dominant perennial grasses in the Otindag Sandland of China, to different sand water content (SWC; 1%, 2%, 3%, 4%, 6%, 8%, 12%, 16%, and 20%) were studied comparatively. The results showed that the germination responses of the two grasses to SWC were similar (i.e. caryopses could not germinate when the SWC was below 3%; at SWC ranging from 3% to 12%, the higher the SWC, the higher the germination percentage; and at a SWC of 12%-20%, germination reached similarly high percentages). At a sand burial depth of 0.5 cm, the threshold of SWC for seedling emergence was 6% forA. cristatum and 8% forB. inermis; at 12%-20% SWC, the seedling emergence of both species reached similarly high percentages. The seedling growth responses of these two species to SWC gradients were different. For A. cristatum, the biomass of seedlings increased with SWC from 6% to 12%, and decreased with SWC from 12% to 20%. For B. inermis, the biomass of seedlings always increased with SWC from 8% to 20%. The results also showed that the seedlings of both species allocated more biomass to the roots with decreases in SWC. The SWC changes from April to October in natural microhabitats of both species suggested that the SWC may play an important role in caryopsis germination, seedling emergence, and the growth characteristics of the two grasses. The responses of caryopsis germination, seedling emergence, and the growth characteristics of these two species to SWC may determine their distribution pattems in the Otindag Sandland.  相似文献   

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Townsend’s big-eared bat, Corynorhinus townsendii, is distributed broadly across western North America and in two isolated, endangered populations in central and eastern United States. There are five subspecies of C. townsendii; C. t. pallescens, C. t. australis, C. t. townsendii, C. t. ingens, and C. t. virginianus with varying degrees of concern over the conservation status of each. The aim of this study was to use mitochondrial and microsatellite DNA data to examine genetic diversity, population differentiation, and dispersal of three C. townsendii subspecies. C. t. virginianus is found in isolated populations in the eastern United States and was listed as endangered under the Endangered Species Act in 1979. Concern also exists about declining populations of two western subspecies, C. t. pallescens and C. t. townsendii. Using a comparative approach, estimates of the genetic diversity within populations of the endangered subspecies, C. t. virginianus, were found to be significantly lower than within populations of the two western subspecies. Further, both classes of molecular markers revealed significant differentiation among regional populations of C. t. virginianus with most genetic diversity distributed among populations. Genetic diversity was not significantly different between C. t. townsendii and C. t. pallescens. Some populations of C. t. townsendii are not genetically differentiated from populations of C. t. pallescens in areas of sympatry. For the western subspecies gene flow appears to occur primarily through male dispersal. Finally, geographic regions representing significantly differentiated and genetically unique populations of C. townsendii virginianus are recognized as distinct evolutionary significant units.  相似文献   

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To determine the vitamins A, C, and E and β-carotene content of Vicia species that can be used in animal feed, a high performance liquid chromatography (HPLC) method was used to investigate the vitamin and β-carotene content in mature and immature seeds of seven Vicia species (Vicia anatolica Turrill., V. ervilia (L.) Willd., V. michauxii Sprengel, V. mollis Boiss. et Hausskn. ex Boiss., V. noeana Reuter ex Boiss., V. peregrina L., and V. sericocarpa Fenzl.), which are useful plants in animal feed in the eastern Anatolia region in Turkey. The vitamin content was found to differ between mature and immature seeds. The levels of vitamins A, C, and E and β-carotene were higher in mature seeds than in immature seeds (P < 0.01).  相似文献   

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