The length and diameter of the coat fibres of the Musk ox

The length and diameter of underwool and outer hairs from captive and selectively-bred Musk oxen were measured. Considerable variation was found between animals and some of its sources were isolated and discussed. Finally, the underwool was compared briefly with other wool fibres, and some implications of the data for studies of prehistoric animal domestication were discussed.     

Problems in meiofauna energy-flow studies

The direct estimation of energy flow through marine meiobenthic populations poses several difficulties, mainly relating to sampling problems. The usefulness of some indirect estimation methods is discussed.Direct production estimates and respiration measurements for three brackish water crustacean populations are given, indicating a relative constant proportion between population production and respiration. The production: assimilation ratio for these populations fluctuates between 0.3 and 0.4. This is contrasted to literature data revealing much higher production: assimilation ratios as determined in the laboratory for nematode populations. Using data on laboratory cultures of the nematode Monhystera disjuncta some factors that can possibly generate this discrepancy are discussed. An analysis of P:B in different life stages of this population justifies the use of a life-cycle turnover of about 3 for meiobenthic populations, provided some conditions are met. Among these is that no drastic change in productivity occurs between juveniles and adults, and that the biomass of hatchlings, not of freshly laid eggs, is considered as generative production.     

Distribution of chromosome breakage point induced by arabinosylcytosine on in-vitro human lymphocytes]

The cytogenetic effects of arabinosyl cytosine on human leukocytes in vitro has been studied using continuous and discontinuous treatments. Optimum activity occurs at the end of the S period. Interchromosomal distribution of breaks is non-random. The hypothesis of a very late replication for some chromatid segments is discussed. The relations between banding and the position of breaks are discussed.     

Taxonomy and phylogenetics: Some considerations

The relationships between taxonomy and phylogenetics are discussed. It is suggested that they are distinct biological subdisciplines and some consequences of this position are set out.     

Fruit body production of macrofungi in some North Norwegian forest types

In 19 forest stands, representing common forest types in N Norway, fixed plots of equal areas have been studied with regard to fruit body production of macrofungi. The fruit bodies were harvested, counted and weighted every second week during the mushroom seasons (late summer and autumn) of 1980, 81, and 82. A number of additional localities have been more superficially investigated with regard to the commercially most interesting species. The production in different forest types is discussed, with special emphasis on mushroom picking for commercial purposes. Phenology of some species is briefly discussed. The different production patterns are discussed, both in relation to climate and to more general conditions for fruit body production. The relationships between forest types and mushroom flora are also discussed. Dominating tree species seems to be of higher importance in terms of similarity in macrofungus species content, than the overall vegetational relationship. Different patterns of fruit body occurrence have led to the establishment of some tentative hypotheses: 1: An unproductive season in terms of mass or fresh weight, is also poor in terms of species number. 2: A locality with a high number of species in a good season, have a relative high number of species also in poor seasons. 3: In good seasons, there is a higher similarity in species content between different localities than in poor seasons. The ecology of some commonly found species are commented upon. There seems to be a tendency that some species which at low altitidues in S Scandinavia are regarded as confined to coniferous forests, are occurring in birch forests in N Norway.     

Recent advances in phytochemistry of bryophytes-acetogenins, terpenoids and bis(bibenzyl)s from selected Japanese, Taiwanese, New Zealand, Argentinean and European liverworts

Bryophytes contain a large number of terpenoids and phenolic compounds. Recent topics relating to the chemical constituents found in 36 Japanese, 3 New Zealand, 2 European, 1 Argentinean and 1 Taiwanese liverworts and 2 Japanese mosses and their biological activity are discussed. The chemosystematics of some liverworts as well as the chemical relationship between liverworts and mosses, and bryophytes and ferns are also discussed.     

Some remarks on the boolean algebra of nervous nets in mathematical biophysics

Recent demonstration by the author has shown that the fundamental equations of the mathematical biophysics of the central nervous system can be considered as describing the behavior of very large numbers of neurons, of which each one follows discontinuous laws, such as discussed by W. S. McCulloch and W. Pitts. In that light some of the old problems are discussed. The comparative merits of the “microscopic” and “macroscopic” approaches are discussed for the problem of the point to point correspondence between the retina and the cortex, with the number of connecting fibers much less than the number of cells. Some aspects of discrimination of intensities are also discussed. Finally, a few generalizations of the McCulloch-Pitts treatment are suggested, and a nervous network is constructed which illustrates some aspects of the perception of numbers.     

黄羽肉鸡微卫星多态性与体重的相关分析

利用选自家禽基因组中的13个微卫星标记,对黄羽肉鸡A系、B系回交F2代群体100个个体的基因组DNA进行PCR扩增,经分析后,计算出各标记的基因频率、多态信息含量、杂合度,通过与性状初生重、8周龄体重的相关分析,得出与体重相关的标记,并进行了同一标记不同基因型间的多重比较。     

The relation between philosophy of science and biology exemplified by the problem of explanation

Summary This paper contains some considerations on the relation between philosophy of science and science, in particular biology. There is a contrast between formalistic and pragmatic approaches to the structure of scientific thought, which is illustrated by the different viewpoints on the nature of explanation. In an appendix some aspects of the logical structure of teleological explanation are discussed.     

激光诱变微生物技术的研究进展

简要概括了国内外在激光诱变微生物领域内的研究新进展,对激光辐照微生物产生生长刺激作用的实验规律、作用机理进行了总结和讨论,在此基础上探讨了激光辐照微生物进行诱变育种的应用性研究。最后,对本领域的发展进行了展望并提出建议。     

Clinical and physiological aspects of the arousal reaction in young children

This review article addresses current knowledge on the arousal reaction during sleep. Diagnostic criteria of the arousal scoring in young children are provided. The possible protective role of the arousal reaction is discussed, and certain abnormalities of the arousal mechanisms in some patients with different types of sleep apneas are considered. Potential links between an abnormal arousal reaction and the origin of the sudden infant death syndrome are discussed.     

蚂蚁群落与栖境关系研究进展及新趋势

生物群落与栖境的关系是生态学研究的核心之一,蚂蚁群落由于在陆地生态系统中的生物量、分布以及具备的生态功能的重要性,是研究这种关系的理想对象。在查阅大量文献的基础上,简述了蚂蚁物种多样性与栖境关系研究现状。介绍了蚂蚁功能群划分以及在不同尺度上与栖境关系的应用研究,评述了功能群应用的限制。阐明了功能特征的定义以及基于形态特征和营养级方面的蚂蚁群落功能特征与栖境的研究,并对功能特征的研究趋势进行了展望。     

Genome size variations in diploid African Coffea species

Flow cytometry was conducted to evaluate genome size diversity among African diploid species of the Coffea genus. The study included 15 species and six new taxa from Congolese and Cameroonian forest regions which have yet to be botanically characterized. Between-population differences were also recorded in some cases. These evaluations using an internal standard were highly correlated with previous results obtained with an external standard, but differences of up to 18 % existed for some species, involving stoichiometric errors. Consequently, genome size variation between species and within species are discussed as true genome size differences or stoichiometric errors. Environmental and phenotypic correlations with genome size are also discussed.     

Phylogeny of the subfamilies of Chironomidae (Diptera)

Summary The phylogeny of the subfamilies of Chironomidae are cladistically analysed using parsimony. A data matrix is presented and some characters discussed. Different outgroup taxa, constraints and options are used, characters unordered or ordered, weighted or unweighted, the results reweighted or not and the results discussed. Telmatogetoninae in all cladograms forms the sister group of the remaining subfamilies. Aphroteniinae in some cladograms forms the sister group of all subfamilies except Telmatogetoninae, whereas in other cladograms, including the preferred cladogram, it is part of Tanypodoinae, which otherwise includes Podonominae, Usumbaromyiinae and Tanypodinae. Chilenomyiinae is basal in Tanypodoinae in some cladograms. In most cladograms, including the preferred cladogram, it is basal in Chironomoinae, which also includes Buchonomyiinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae. The preferred cladogram is compared with the relationships between different subfamilies suggested by previous authors.     

银杏酸单体的合成及构效关系研究进展

银杏酸的研究已经成为继银杏黄酮和内酯后的热点.本文综述了银杏酸同系物的结构及部分单体的合成研究进展,分析了合成路线,讨论了各合成方法的特点及适用性,并总结了银杏酸的结构和部分药理活性的关系.     

Myofascial force transmission and tendon transfer for patients suffering from spastic paresis: A review and some new observations

The current rationale of clinical practice in spastic tendon transfer surgery is based on four assumptions: (1) changes in muscle fiber length (serial number of sarcomeres) determine the available length range and joint excursion, (2) muscle cross-sectional area determines the maximal force output, (3) fiber length and muscle force are invariable functions of muscle length, (4) there is an invariable relation between the elastic force and the active force exerted by the sarcomeres. The validity of these assumptions is discussed. Additionally, some new perspectives in muscle research are discussed and myofascial force transmission is introduced as a co-determinant for the outcome of tendon transfer by presenting some exploratory observations.     

Mechanistic comparisons among base excision repair glycosylases

The mechanisms by which various DNA glycosylases initiate the base excision repair pathways are discussed. Fundamental distinctions are made between "simple glycosylases," that do not form DNA single-strand breaks, and "glycosylases/abasic site lyases," that do form single-strand breaks. Several groupings of BER substrate sites are defined and some interactions between these groupings and glycosylase mechanisms discussed. Two characteristics are proposed to be common among all BER glycosylases: a nucleotide flipping step that serves to expose the scissile glycosyl bond to catalysis, and a glycosylase transition state characterized by substantial tetrahedral character at the base glycosyl atom.     

A serological investigation on the phylogenetic relationship of arthropod classes

Serological kinship of some representative species of arthropods belonging to Crustacea, Arachnida, Myriapoda and Insecta has been studied. There ist weak serological correspondence between the myriapods and insects. The same is the case between Crustacea and Arachnida, and no correspondence was seen between Myriapoda and Insecta on one hand and Crustacea and Arachnida on the other. The results are discussed in relation to the different previous views on the origin and evolution of Arthropoda.     

Signs of fitness and allozyme heterozygosity in an artificial population of sable Martez zibellinna L

Associations between some characteristics of fitness (the age of the first reproduction, life span, fertility, and number of missed pregnancies) and heterozygosity for some allozyme loci have been studied in a population of the sable Martez zibellinna L. kept in cages at a farm. Of all fitness characteristic studied, a weak correlation has only been found between heterozygosity and the age of the first reproduction (maturation rate). The age of the first reproduction is positively associated with the life span and fertility. The results obtained are discussed in terms of the relationship between the genetic variation of longevity and developmental rate and prospects of their application to breeding practice.     

Outline of a mathematical theory of the removal of malarial parasites from the blood stream

By making some plausible assumptions, a set of differential equations is proposed which describes the kinetics of interaction between periodically multiplying parasites and continuously produced phagocytes. These equations establish some general conditions which are necessary in order that the number of parasites should increase or decrease. Some consequences of the equations are discussed, and some experimental procedures for the determination of the parameters entering those equations are suggested.