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1.
2.
Tom Müller 《Biodiversity and Conservation》1994,3(2):116-125
The need to integratein situ conservation into the planning process is outlined, and the importance of vegetation survey to determine conservation priorities and to identify areas suitable forin situ conservation is stressed. A case is presented, drawing on experience gained in Zimbabwe, of how a botanical institute can become an integral part of biological conservation. The institute should consist of a herbarium, a botanical garden, a gene bank and a vegetation survey unit. The function of each section, how they interlink, and how they can be integrated are discussed. 相似文献
3.
Barry M. Gordon 《Biological trace element research》1987,12(1):153-159
Information concerning the chemical state of trace elements in biological systems generally has not been available. Such information
for toxic elements and metals in metalloproteins could prove extremely valuable in the elucidation of their metabolism and
other biological processes. The shielding of core electrons by binding electrons affect the energy required for creating inner-shell
holes. Furthermore, the molecular binding and symmetry of the local environment of an atom affect the absorption spectrum
in the neighborhood of the absorption edge. X-ray absorption near-edge structure (XANES) using synchrotron radiation excitation
can be used to provide chemical speciation information for trace elements at concentrations as low as 10 ppm. The structure
and position of the absorption curve in the region of an edge can yield vital data about the local structure and oxidation
state of the trace element in question. Data are most easily interpreted by comparing the observed edge structure and position
with those of model compounds of the element covering the entire range of possible oxidation states. Examples of such analyses
will be reviewed. 相似文献
4.
黑龙江省三江平原丹顶鹤的数量分布 总被引:2,自引:0,他引:2
在地面调查的基础上,我们使用Y-11轻型飞机对黑龙江省三江平原地区的丹顶鹤的数量分布近行了调查,调查时飞行高度80米,航速140公里/小时,续航里程共3748公里。调查结果表明,丹顶鹤在三江平原主要分布在8个地区,其中嘟噜河下游、洪河自然保护区、七星河流域和兴凯湖低地是主要繁殖地,总数量共309只。 相似文献
5.
6.
The Castel di Guido site, with an estimated age of approximately 300,000 years, has yielded abundant animal remains, Acheulian stone and bone bifaces, and small tools. On the surface of the original deposit, turned over by agricultural activities, fragments of human remains were discovered between 1980 and 1986, including a temporal bone described here. 相似文献
7.
Phylogenetic Survey of Proteins Related to Synapsin I and Biochemical Analysis of Four Such Proteins from Fish Brain 总被引:1,自引:1,他引:0
A phylogenetic survey of proteins immunologically related to Synapsin I, a major synaptic vesicle-associated phosphoprotein in mammals was carried out. Proteins antigenically related to Synapsin I were found by use of radioimmunoassay and other radioimmunochemical techniques in the nervous systems of several vertebrate and invertebrate species, which included birds, reptiles, amphibians, fish, echinoderms, arthropods, and mollusks. Four proteins present in fish brain, antigenically related to Synapsin I, were further studied and found to resemble mammalian Synapsin I in several respects. Like Synapsin I, the fish proteins were present in high amounts in nervous tissue, were enriched in synaptosomal fractions of brain where they were substrates for endogenous protein kinases, were acid extractable, and were sensitive to digestion by collagenase. In addition, two-dimensional peptide-mapping analysis revealed some homology between major phosphopeptide fragments of Synapsin I and the fish proteins. The results indicate that proteins related to Synapsin I are wide-spread in the animal kingdom. 相似文献
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9.
The incidence of lethal parasites in the larvae of a Tipula paludosa population was monitored for two seasons. The proportions of larvae infected with Tipula iridescent virus (TIV) and a tachinid insect were similar to those in previously studied populations, whereas the proportions of larvae infected with Tipula nuclear polyhedrosis virus (NPV) and a spore-forming bacterium (SFB) were higher. Conservative estimates of mortality due to these four agents were 10.7% in 1977–1978 and 7.7% in 1978–1979. The mean population density and the proportion of SFB-infected larvae were lower in 1978–1979 than in 1977–1978, while the proportion of NPV-infected larvae was higher. In 1979 the proportion of NPV-infected larvae was positively correlated with population density, which was highest in the wettest part of the study area. In both seasons the proportion of SFB-infected larvae was negatively correlated with population density. Larvae infected with the NPV or the SFB became pallid at an advanced stage of infection, but, although infected larvae were found throughout the larval period, pallid larvae were only found in the later part. It is suggested that larvae become infected in an early instar, then the infections slowly develop throughout the remainder of the larval period. Five larvae were found with mixed infections; four were infected with the SFB and NPV, while the fifth was infected with the SFB and TIV. 相似文献
10.
D. Chen 《Human Evolution》1989,4(1):73-86
In approaching the taxonomy of Neolithic Man and its phylogenetic relationship to Later Paleolithic Man and Modern Man in
China, the statistical methods used here are Penrose's shape distance and PCA (Principal Component Analysis). The scattergram
based on principal component scores, combines the dendrogram based on Penrose's shape distance, and takes the male taxonomy
into main consideration, but takes the female taxonomy — as a reference only because the differentiations in physical characteristics
among male populations generally are rather larger than those among the female populations. Thus according to this scattergram,
Neolithic Man in China can be divided into two large groups: the Northern China group, and the Southern China group. The theory
is that in Hengzhen there exist some blood mixtures between the Southern China Group and the Northern China Group (especially
the third subgroup) of Neolithic Man. Later Paleolithic Man of China — Liujiang and Upper-Cave Man — can also clearly distinguished
from the rest of Neolithic Man in China in the scattergram, and can be considered as two different local types of Later Paleolithic
Man. So-called “Negro-Australoid” racial traits can themselves be doubtlessly traced back to Later Paleolithic Man of China
— Liujiang and Upper-cave Man. These traits are the intrinsic characteristics of Neolithic Man in China and only then is there
slight difference in the extent of the manifestation of these traits in the population. 相似文献