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1.
广西金钟山鸟类保护区鸟类多样性初步研究 总被引:7,自引:0,他引:7
本文共记录到金钟山鸟类274种,分别隶属于18目57科,其中陆生鸟类251种,水鸟23种;以留鸟为主,共157种;候鸟、旅鸟分别为104种、13种;东洋种为优势类群,共有171种,古北种和广布种分别为4种、27种。这些鸟类中有国家重点保护鸟类39种,中国特有种鸟类3种,列入世界自然保护联盟红皮书名录中的鸟类5种,列入中国濒危动物红皮书名录中的鸟类20种,列入CITES附录中的鸟类34种。本文还对金钟山鸟类保护区的5种不同生境类型的鸟类种类组成作了比较,结果表明灌丛+农田的鸟种多样性指数最高,为3.04;水域的鸟种多样性指数最低,为2.14。 相似文献
2.
Permanent Stained Agar Preparation of Mycoplasma and of L Forms of Bacteria 总被引:7,自引:3,他引:4
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Louis Dienes 《Journal of bacteriology》1967,93(2):689-692
A procedure is described that permits the preparation of permanent stained mounts of Mycoplasma and of bacterial L forms grown on the surface of and within agar media. These preparations are especially useful for making representative photographs. The cultures are fixed with Formalin vapor. Thin slices of agar are stained at elevated temperature between 50 and 60 C and at a low pH, are dried rapidly, and are mounted in Canada balsam. The results with this staining procedure are illustrated by photographs of various strains of Mycoplasma and of bacterial L forms. 相似文献
3.
Sources of modern vestibulology's crisis status are determined. New methodological questions of object exploration of vestibular function and vestibular reactions are marked. New theoretical views are developed, some results of these theoretical views's practical realization are presented, perspective possibilities of new approach are defined. 相似文献
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Ampullae of Lorenzini are sensitive electroreceptors. Applied potentials affect receptor cells which transmit synaptically to afferent fibers. Cathodal stimuli in the ampullary lumen sometimes evoke all-or-none "receptor spikes," which are negative-going recorded in the lumen, but more frequently they evoke graded damped oscillations. Cathodal stimuli evoke nerve discharge, usually at stimulus strengths subthreshold for obvious receptor oscillations or spikes. Anodal stimuli decrease any ongoing spontaneous nerve activity. Cathodal stimuli evoke long-lasting depolarizations (generator or postsynaptic potentials) in afferent fibers. Superimposed antidromic spikes are reduced in amplitude, suggesting that the postsynaptic potentials are generated similarly to other excitatory postsynaptic potentials. Anodal stimuli evoke hyperpolarizations of nerves in preparations with tonic activity and in occasional silent preparations; presumably tonic release of excitatory transmitter is decreased. These data are explicable as follows: lumenal faces of receptor cells are tonically (but asynchronously) active generating depolarizing responses. Cathodal stimuli increase this activity, thereby leading to increased depolarization of and increased release of transmitter from serosal faces, which are inexcitable. Anodal stimuli act oppositely. Receptor spikes result from synchronized receptor cell activity. Since cathodal stimuli act directly to hyperpolarize serosal faces, strong cathodal stimuli overcome depolarizing effects of lumenal face activity and are inhibitory. Conversely, strong anodal stimuli depolarize serosal faces, thereby causing release of transmitter, and are excitatory. These properties explain several anomalous features of responses of ampullae of Lorenzini. 相似文献
6.
Populations oscillations in isolated populations of flies are considered. Qualitative methods of analysis are applied to the functional differential equation representing the system and conditions for the occurrence of oscillations are derived. These conditions are readily visualized in terms of parameters which are easily measured and have a straightforward biological interpretation. 相似文献
7.
Insights about scaling of folding properties of proteins are obtained bystudying folding in heteropolymers described by Go-like Hamiltonians. Bothlattice and continuum space models are considered. In the latter case, themonomer-monomer interactions correspond to the Lennard-Jones potential.Several statistical ensembles of the two- and three-dimensional targetnative conformations are considered. Among them are maximally compactconformations which are confined to a lattice and those which are obtainedeither through quenching or annealing of homopolymers to their compactlocal energy minima. Characteristic folding times are found to grow aspower laws with the system size. The corresponding exponents are notuniversal. The size related deterioration of foldability is found to beconsistent with the scaling behavior of the characteristic temperatures:asymptotically, the folding temperature becomes much lower than thetemperature at which glassy kinetics become important. The helicalconformations are found to have the lowest overall scaling exponent andthe best foldability among the classes of conformations studied. Thescaling properties of the Go-like models of the protein conformationsstored in the Protein Data Bank suggest that proteins are not optimizedkinetically. 相似文献
8.
Dinesh S. Bhoj Mohammad Ahsanullah 《Biometrical journal. Biometrische Zeitschrift》1993,35(3):355-359
The test statistics are proposed for testing the equality of the coefficients of variation of two normal populations based on independent samples. The asymptotic distributions of the statistics are approximated by well-known distributions. The empirical sizes and powers of these statistics are computed and compared. 相似文献
9.
《Plant and Soil》1971,35(1):39-45
Summary 1. Auxotrophic mutants of 2 strains ofRhizobium meliloti have been isolated: among them 4 are purine or pyrimidine-dependent (adenine, cytosine), 4 are sulfur amino acid-dependent
(methionine, cysteine) and 3 glycine-dependent.
2. All of these mutants induce nodule formation on lucerne (variety ‘Du Puits’).
3. There are associations between nutritional requirements and effectiveness in nitrogen fixation on this host. All the amino
acid-dependent mutants are effective. Glycine-dependent mutants are more effective than the wild-type strain, whereas cyste?ne
and methionine-dependent mutants are as effective as the wild-type strain. On the other hand, purine and pyrimidine-dependent
mutants are ineffective.
4. All the prototrophic revertants of ineffective auxotrophic strains are effective. Some of them are more effective than
wild-type strain. 相似文献
10.
H T Wright 《Journal of molecular biology》1973,79(1):1-11
The crystal structures of chymotrypsinogen-A and α-chymotrypsin are compared and the parts of the main chain which differ in the two structures are identified. Changes in main-chain torsion angles and hydrogen bonds are tabulated. The residues Asp(102), His(57) and Ser(195) are compared in detail. Possible relationships among those parts of the molecules which change upon activation are discussed. 相似文献
11.
银杏种子的生物学特性及贮藏 总被引:1,自引:0,他引:1
银杏种子是典型的生理后熟种子,种子含水量高,种皮通透性大,具有不耐脱水的特性,是非典型性顽拗性种子。银杏种子贮藏的关键是在保持种子活力的前提下,降低种子的呼吸强度,因此贮藏过程中温度、湿度和气体的调节是关键。涂膜处理、化学试剂处理、辐射处理和逆境处理等技术可有效提高银杏种子的贮藏品质。 相似文献
12.
甘肃崆峒山种子植物区系科的分析 总被引:7,自引:0,他引:7
崆峒山位于甘肃省平凉市境内 ,面积约 1 82 .5 2km2 。有野生种子植物 662种 ,隶属于 3 43属 ,88科。其中世界广布科 2 3个 ,占总科数的 2 6.1 4 %;热带科 3 5个 ,占 3 9.77%;温带科 3 0个 ,占 3 4.0 9%,并且单属科和少属科较丰富。虽然热带科的比例较高 ,但分布至该区的属和种大多是温带性质的。崆峒山的优势科是菊科、禾本科、蔷薇科、豆科、唇形科等 ,而表征科则是桦木科、麻黄科、胡颓子科、忍冬科、罂粟科、榆科、金粟兰科、虎耳草科等。该区系的起源有明显的古老性。 相似文献
13.
L. A. Nevesskaja 《Paleontological Journal》2009,43(1):1-11
The systems of the class Bivalvia accepted in recent manuals are discussed. The system proposed by L.A. Nevesskaja, O.A. Skarlato, Ya.I. Starobogatov, and A.G. Eberzin (1971) is substantiated and updated. Morphological characters important for the establishment of taxa of different ranks are listed. Three superorders and 17 orders are established; two orders, which are restricted to the Cambrian and the beginning of the Ordovician, are placed outside the accepted superorders. 相似文献
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General problems of classification and nomenclature of human diseases caused by agents of biological nature are reviewed. From biological and epidemiological position, prion diseases that belong to non-infectious human pathology are analyzed. Directions of improvement of ecologic-etiologic and ecologic-epidemiologic classifications and nomenclature of human diseases caused by infectious, invasive and prion agents are determined. 相似文献
16.
Ewa Majchrzak 《Molecular & cellular biomechanics : MCB》2013,10(3):201-232
Heat transfer processes proceeding in the living organisms are described by the different mathematical models. In particular, the typical continuous model of bioheat transfer bases on the most popular Pennes equation, but the Cattaneo-Vernotte equation and the dual phase lag equation are also used. It should be pointed out that in parallel are also examined the vascular models, and then for the large blood vessels and tissue domain the energy equations are formulated separately.
In the paper the different variants of the boundary element method as a tool of numerical solution of bioheat transfer problems are discussed. For the steady state problems and the vascular models the classical BEM algorithm and also the multiple reciprocity BEM are presented. For the transient problems connected with the heating of tissue, the various tissue models are considered for which the 1st scheme of the BEM, the BEM using discretization in time and the general BEM are applied.
Examples of computations illustrate the possibilities of practical applications of boundary element method in the scope of bioheat transfer problems. 相似文献
17.
S. N. Moralev E. V. Rozengart 《Journal of Evolutionary Biochemistry and Physiology》2008,44(4):414-429
Analytical review of the literature data on interaction constant of cholinesterases from different animal (vertebrates and squids) with 45 bis-onium reversible inhibitors forming homologous series with regularly varied structure has been carried out. Values of the competitive, uncompetitive and generalized inhibitor constants are compared. Interspecies and intraspecies differences in sensitivity of ChE are revealed. Results of conformational analysis of the investigated ligand molecules are presented. The data on population of individual conformations are compared with the data on anticholinesterase potency. Conclusions are made on the action mechanism of the investigated compounds and predominant place of their sorption. The presented data are considered from the point of view of comparative biochemistry and in the light of current information about the active center structure of cholinesterases. 相似文献
18.
Patnaik PR 《Biotechnology advances》1999,17(6):477-488
Artificial neural networks (ANN) are being applied to recovery of products from fermentation broths. Recovery methods for which mathematical models are complex or non-existent are particularly suitable for control and analysis by ANNs. Use and potential of artificial neural networks for product recovery applications are reviewed. 相似文献
19.
L. R. Cleveland 《The Journal of eukaryotic microbiology》1957,4(4):230-241
SUMMARY. Two centrioles, an old one and a new one, are always present in the resting cell. From prophase onward two new ones and two old ones are present. Beginning with the resting stage, five types of centriole life cycles are described and compared with one another: In type 1, both centrioles are elongate; in type 2, the old one is long and the new one, which is short, elongates in prophase; in type 3, both are short, both elongate in prophase, and both, except for their anterior tips, degenerate in late telophase; in type 4, both are long but in prophase their distal ends become free of the rest of the centrioles, these ends migrate to center or posterior end of cell, where, after they produce the achromatic figure and it completes its function in nuclear division, they degenerate; in type 5, both are short and neither elongates at any stage of its life cycle.
New centrioles are produced by the anterior ends of old ones. In their first generation, centrioles produce only extranuclear organelles (flagella, parabasals, axostyles, etc.); in their second and later generations, they produce only the achromatic figure (gametogenesis in Trichonympha and reorganization in Barbulanympha and Rhynchonympha are exceptions to this rule).
The distal ends of centrioles in some types of cycles are surrounded by centrosomes; in others they are not. In one type of centriole life cycle a small central spindle is present in the resting cell in two genera; in the other types this is not the case. 相似文献
New centrioles are produced by the anterior ends of old ones. In their first generation, centrioles produce only extranuclear organelles (flagella, parabasals, axostyles, etc.); in their second and later generations, they produce only the achromatic figure (gametogenesis in Trichonympha and reorganization in Barbulanympha and Rhynchonympha are exceptions to this rule).
The distal ends of centrioles in some types of cycles are surrounded by centrosomes; in others they are not. In one type of centriole life cycle a small central spindle is present in the resting cell in two genera; in the other types this is not the case. 相似文献
20.
I. B. Onukogu 《Biometrical journal. Biometrische Zeitschrift》1985,27(4):375-383
This paper considers a common problem in analysis of variance where the responses to a set of treatments are nominal (i.e. are recorded in frequencies) with no underlying metric. Reasoning by analogy from standard analysis of variance of a two-way classification we develop chi-square tests for significance of treatments and interactions. Two tests are proposed for interaction and their asymptotic properties are studied. 相似文献