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Is fertility relevant to evolutionary analyses conducted in modern industrial societies? This question has been the subject of a highly contentious debate, beginning in the late 1980s and continuing to this day. Researchers in both evolutionary and social sciences have argued that the measurement of fitness-related traits (e.g., fertility) offers little insight into evolutionary processes, on the grounds that modern industrial environments differ so greatly from those of our ancestral past that our behavior can no longer be expected to be adaptive. In contrast, we argue that fertility measurements in industrial society are essential for a complete evolutionary analysis: in particular, such data can provide evidence for any putative adaptive mismatch between ancestral environments and those of the present day, and they can provide insight into the selection pressures currently operating on contemporary populations. Having made this positive case, we then go on to discuss some challenges of fertility-related analyses among industrialized populations, particularly those that involve large-scale databases. These include “researcher degrees of freedom” (i.e., the choices made about which variables to analyze and how) and the different biases that may exist in such data. Despite these concerns, large datasets from multiple populations represent an excellent opportunity to test evolutionary hypotheses in great detail, enriching the evolutionary understanding of human behavior. 相似文献
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Properties of several products of cyclo-oxygenation of polyunsaturated fatty acids: prostacyclin, prostaglandins 6-keto E1, E2, D2, D3 are reviewed in relation to their antiplatelet activity. 相似文献
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Angelo F. Benedetto Philip J. Squattrito Fabrizio Adani Enzo Montoneri 《Inorganica chimica acta》1997,260(2):1145-216
A study of the salts of 4-fluoro-3-sulfobenzylphosphonic acid has resulted in the synthesis of two new compounds with unusual layered structures. The crystal structures of these salts and the parent acid have been determined by single crystal X-ray methods. Crystal data: 4-F-3-SO3H-C6H3CH2PO3H2·H2O: triclinic, space group
for 1519 observations (l>3σ(l)) and 182 variables; [Ni(NH3)2(H2O)4]3(4-F-3-SO3-C6H3-CH2PO3)2·4H2O: triclinic, space group
for 2689 observations (l>3σ(I)) and 511 variables: Na3(4-F-3-SO3-C6H3CH2PO3)- 8.5H2O: monoclinic, C2/c, Z = 8, A = 25.636(4), B = 6.218(4), C = 24.136(2) Å, β = 98.33(1)°, V = 3807(3) Å3, R(F) = 0.047 for 2262 observations (I>2;3σ(I)) and 254 variables. The parent acid monohydrate crystallizes in layers with the acidic groups directed to the faces of the layer. The water molecules are in between the layers hydrogen-bonded to the sulfonate oxygen atoms. The nickel salt contains three independent cations, each of which is hexacoordinated to a mixture of water and ammonia molecules. Thus, there is no direct coordination of the nickel by either the sulfonate or phosphonate oxygen atoms. The structure has alternating layers, the first formed by the anions and one of the nickel complexes, and the second by the other two complexes and the free water molecules. The sodium salt also has the anions arranged in layers but with an interpenetrating three-dimensional network of ionic and hydrogen bonds involving the cations and water molecules. The sodium ions are coordinated to a mixture of sulfonate oxygen atoms and bridging water molecules in irregular six-fold environments. These structures are discussed in terms of the coordination behavior of the difunctional anions in the context of known monofunctional phosphonate and sulfonate compounds. 相似文献
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The chromosome number ofCitrus penvisculata, Mayer lemon, Italian lemons. Kagzi Kalan lemon, Hill lemon and Nepale oblong lemon has been found to be 2n=18. Bridge-fragment configurations were observed inC. penvisculata, Mayer lemon, Italian round and Kagzi Kalan lemon. Univalents and pollen sterility have been observed in varying proportions in all of the seven species and varieties. Pollen sterility is probably due to presence of univalents and inversion heterozygosity 相似文献
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Over 300 bacterial strains were isolated from seven samples of activated sludge by plating on sewage agar. Gram-negative bacteria of the genera Zoogloea and Comamonas predominated. Many isolates (51%) showed sudanophilic inclusions of poly-β-hydroxybutyric acid, whereas 34% accumulated iodophilic material on media containing starch. A large number required either vitamins or amino acids, or both, for growth. None of the isolates tested for their ability to bring about changes in autoclaved sewage produced an effluent comparable in quality to the activated sludge control, although the Zoogloea did produce activated sludgelike flocs. A study of 150 bacterial strains isolated from raw sewage revealed that they differed from the sludge isolates in several respects. Coliforms, which constitute nearly a quarter of the sewage isolates, were rarely encountered in sludge. 相似文献
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《Inorganica chimica acta》1988,146(1):33-35
The preparation of various phosphonium hexachlorozirconates from zirconium tetrachloride and zirconium oxide chloride octahydrate is described. In one case a product [(C6H5)3PH]2ZrCl6 was found to be unusually resistant to hydrolysis. 相似文献