首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
The European newts have been the subject of several phylogenetic analyses, using a variety of character sets, from biochemical to ethological. As a result, the European newts have probably been subjected to more diverse and intense phylogenetic analysis than any other vertebrate genus in the world. The various techniques used have yielded conflicting results, but recent analyses that combine different kinds of data promise a resolution of the problem.  相似文献   

4.
《CMAJ》1945,52(6):614-615
  相似文献   

5.
6.
The chromosome numbers of the five European seagrasses have been determined in material from several sites along the coasts of the Atlantic Ocean, the North Sea and the Mediterranean:Zostera marina L., 2n = 12;Z. noltii Hornem., 2n = 12;Posidonia oceanica (L.)Delile, 2n = 20;Cymodocea nodosa (Ucria)Aschers., 2n = 14, 2n = 28;Halophila stipulacea (Forsk.)Aschers., 2n = 18. The difference in chromosome morphology betweenZ. marina andZ. noltii supports the division of the genus into two subgenera.  相似文献   

7.
Over the last few years, many European and North American countries have reported a high rate of disorders (mortality, dwindling and disappearance) affecting honeybee colonies (Apis mellifera). Although beekeeping has become an increasingly professional activity in recent years, the beekeeping industry remains poorly documented in Europe. The European Union Reference Laboratory for Honeybee Health sent a detailed questionnaire to each Member State, in addition to Kosovo and Norway, to determine the demographics and state of their beekeeping industries. Based on data supplied by the National Reference Laboratory for honeybee diseases in each European country, a European database was created to describe the beekeeping industry including the number and types of beekeepers, operation size, industry production, and health (notifiable diseases, mortalities). The total number of beekeepers in Europe was estimated at 620 000. European honey production was evaluated at around 220 000 tons in 2010. The price of honey varied from 1.5 to 40 €/kg depending on the country and on the distribution network. The estimated colony winter mortality varied from 7 to 28% depending on the country and the origin of the data (institutional survey or beekeeping associations). This survey documents the high heterogeneity of the apicultural industry within the European Union. The high proportion of non-professional beekeepers and the small mean number of colonies per beekeeper were the only common characteristics at European level. The tremendous variation in European apicultural industries has implication for any comprehensive epidemiological or economic analysis of the industry. This variability needs to be taken into account for such analysis as well as for future policy development. The industry would be served if beekeeping registration was uniformly implemented across member states. Better information on the package bee and queen production would help in understanding the ability of the industry to replace lost honey bee stocks.  相似文献   

8.
9.
10.
11.
The environment does not recognize national boundaries. Nor, increasingly, does trade. There is, therefore, a need to harmonize the regulation of the planned release of organisms containing recombinant DNA. This is particularly important for the geographically and economically interdependent countries in Europe. The various nations within the European Community have responded differently to proposals for planned release. An important step towards harmonization has been made with the OECD report on recombinant DNA. Yet there is still scope for a Community-wide framework of regulation.  相似文献   

12.
13.
14.
15.
A systematic reassessment of megafossil records ofFagaceae in Central Europe has been undertaken on the basis of leaf cuticular characters. The oldest representatives date back to the Eocene:Quercus subhercynica spec. nova,Dryophyllum furcinerve (Rossm.)Schmalh.,Trigonobalanopsis rhamnoides (Rossm.) gen. & comb. nov. In the Oligocene other members of extant genera appear:Quercus rhenana (Weyl. & Kilpp.)Knobloch & Kvaek,Fagus attenuata Goepp.,Lithocarpus saxonicus spec. nova. In the Neogene these ancient taxa (except inFagus lineage), are gradually replaced by deciduous species ofQuercus andCastanea. Trigonobalanus andCastanopsis are recorded by fruits (or wood) only.  相似文献   

16.
17.
Relationships and origins of the European lagomorphs   总被引:1,自引:0,他引:1  
G. B. CORBET 《Mammal Review》1986,16(3-4):105-110
  相似文献   

18.
19.
20.
The paper presents the values of total protein (TP) and protein fractions in the serum of 57 European bisons from the Bia?owieza Primeval Forest, 47 of these animals being free-ranging and 10 living in enclosures. It was found that the amount of TP and amount of alpha 1- and gamma-globulin fractions are significantly lower in adult females than males. The amount of TP and gamma-globulin fraction increase significantly with age in all examined Europeans bisons, whereas the amount of alpha 1- and alpha 2-globulin fractions increase only in free-ranging animals.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号