Use of "fermosine"--fodder yeast in a multi-generation trial with chickens. 3. Evaluation of health safety in a long-term toxicologic test     

H Bentz  G Richter  H Richter  J Schleicher 《Archives of Animal Nutrition》1985,35(10):715-722

In a 3-generation experiment with a total of 2520 hens and 210 cocks of the species 'White Leghorn' kept in cages, the compatibility of 5.0%, 7.5% and 15% 'fermosin' torula yeast in the mixed feed ration was tested under long-term toxicologic aspects. The parameters investigated and relevant for the toxicological statement, with high probability, did not show a negative influence of the test ration. Thus, a good compatibility of the tested yeast product 'fermosin' for laying hens can be stated.  相似文献   

Plant species richness and composition in managed grasslands: The relative importance of field management and environmental factors     

Sebastian Klimek  Anne Richter gen. Kemmermann  Johannes Isselstein 《Biological conservation》2007,134(4):559-570

Decline of grassland diversity throughout Europe within the last decades is threatening biological diversity and is a major conservation problem. There is an urgent need to determine the underlying factors that control vascular plant species richness and composition in managed grasslands. In this study, 117 grasslands were sampled using standardised methods. Explanatory variables were recorded for each grassland site, reflecting the local field management, site-specific environmental conditions and large-scale spatial trends. Using variation partitioning methods, we determined the pure and shared effects of these three sets of explanatory variables on the plant species richness and composition in grasslands. Most of the explained variation in plant species richness was related to the joint effect of local field management and environmental variables. However, the applied variation partitioning approach revealed that the pure effect of spatial variables contributed relatively little to explaining variation in both the plant species richness and species composition. The largest fractions of explained variation in plant species composition were accounted for by the pure effects of environmental and local field management variables. Moreover, the results revealed that the main mechanisms by which these sets of explanatory variables affect plant species vary according to the type of management regime under study. From our findings we could conclude that particularly a reduction of nitrogen fertilisation on meadows and grazing at a low stocking rate on pastures can help to conserve biodiversity.  相似文献   

Nitrogen mineralization in loamy arable soils after increasing the ploughing depth and ploughing grasslands   总被引：2，自引：0，他引：2  

G.M. Richter  A. Hoffmann  R. Nieder  J. Richter 《Soil Use and Management》1989,5(4):169-173

Abstract. Increasing the ploughing depth and ploughing in grassland has been common in Germany during the past 20 years. Incubation studies were conducted with topsoils from luvisols and gleysols at different times after change of management in order to assess its influence on nitrogen mineralization and its kinetic parameters.
The results show that deep ploughing slows the mineralization of nitrogen. The difference between earlier (1967–72) and more recently (1980–82) deepened topsoil has become smaller after a further three years of cultivation, however. The preceding crops (wheat or sugar beet), the amount of N fertilizer as well as clay and nitrogen contents cause a variation in N mineralization. The results indicate a continuing approach of an'equilibrium'organic matter and nitrogen content. The enrichment capacity of intensively managed soils may be replenished within 10 years.
Gleysols formerly under grass mineralize more nitrogen than'traditionally'ploughed soils, even 27 years after the ploughing-in. While nitrogen from easily decomposable materials decreases within the first 10 years, the resistant fraction is a long-lasting determinant for N mineralization. Both processes need to be considered when applying fertilizer to minimize nitrate leaching.  相似文献   

Ein Vergleich deutscher und schweizerischer Regensimulatoren nach Regenstruktur und kinetischer Energie     

Josef M. Hassel  Gerold Richter 《植物养料与土壤学杂志》1992,155(3):185-190

Comparison of German and Swiss Rainfall Simulators - Rain Structure and Kinetic Energy The drop size distributions of the investigated rain are significantly different. The rainfall simulators Swanson, Bonn, Basel and Trier culminate in the 2 - 3 mm drop diameter class (～40%) and thus simulate best the drop size distribution of natural heavy rainfall. The structure and the kinetic energy of the rains of eight rainfall simulators have been investigated. The data are compared to those registered during a thunder-shower at the research station of Mertesdorf near Trier/FRG. The results are summarized as follows:

• The impact velocity of artificial raindrops depends on the water pressure within the rainfall simulator, the initial velocity of the raindrops and the fall height. A correction factor to match the kinetic energy of natural rainfall, which is based on the percentage of deviation from the terminal velocity, can be applied only to some extend.
• With respect to various fall velocities of the artificial raindrops all tested rainfall simulators except one yield a rainfall energy between 19 and 27 J/m² per mm of rainfall.
• The actual amount of precipitation measured at the end of the rainfall experiments sometimes differs significantly from the aimed value of 60 mm/h. Due to this variation, the total rainfall energy during the experiments accumulated to 9 - 15 MJ/ha.
• This high variability depends on the used rainfall simulator. But it also demonstrates the importance of precipitation measurements on the plot during simulations in order to exactly calculate the rainfall energy.

  相似文献   

An Improved Moist Chamber Slide for Use in Micromanipulation     

Richter KM 《Science (New York, N.Y.)》1948,108(2799):192

  相似文献   

MAGNITUDE AND ENERGY OF EARTHQUAKES     

Gutenberg B  Richter CF 《Science (New York, N.Y.)》1936,83(2147):183-185

  相似文献   

5-HT4(a) receptors avert opioid-induced breathing depression without loss of analgesia     

Manzke T  Guenther U  Ponimaskin EG  Haller M  Dutschmann M  Schwarzacher S  Richter DW 《Science (New York, N.Y.)》2003,301(5630):226-229

Opiates are widely used analgesics in anesthesiology, but they have serious adverse effects such as depression of breathing. This is caused by direct inhibition of rhythm-generating respiratory neurons in the Pre-Boetzinger complex (PBC) of the brainstem. We report that serotonin 4(a) [5-HT4(a)] receptors are strongly expressed in respiratory PBC neurons and that their selective activation protects spontaneous respiratory activity. Treatment of rats with a 5-HT4 receptor-specific agonist overcame fentanyl-induced respiratory depression and reestablished stable respiratory rhythm without loss of fentanyl's analgesic effect. These findings imply the prospect of a fine-tuned recovery from opioid-induced respiratory depression, through adjustment of intracellular adenosine 3',5'-monophosphate levels through the convergent signaling pathways in neurons.  相似文献   

饲养水平和遗传特性对XX;mas-1/mas-+鲤鱼(Cyprinus carpio L.)性别决定的影响     

张东鸣  J.Komen  C.J.J.Richter  陈颖 《吉林农业大学学报》2002,24(3):96-101

饲养水平对E4×E5 (XX ;mas- +/mas- +×XX ;mas- 1/mas - 1)鲤鱼 (CyprinuscarpioL )F1代的性别决定有显著影响 ,高饲养水平和低饲养水平处理组中雌性比率分别为 5 1 5 %和 4 1%。遗传特性对E4 5×E5 (XX ;mas- 1/mas - +×XX ;mas- 1/mas- 1)F1代的影响比饲养水平的影响显著 ,在 2个处理组中只发现 1～ 2尾雌性。 2个饲养水平对E4×E4 5 (XX ;mas- +/mas- +×XX ;mas- 1/mas - +)F1代的影响差异显著 ,高饲养水平 2个处理组中雌性比率分别为 86 2 %和 76 8% ,而低饲养水平 2个处理组中雌性比率分别为 76 8%和 5 7 9% ,高饲养水平处理组的雌性比率与低饲养水平处理 1组 (雌性比率 5 7 9% )相比差异显著。 2个饲养水平条件下E4×E5和E4×E4 5后代的XX ;mas - 1/mas - +鲤鱼性别转化率之间没有显著差异。  相似文献   

From the psi to charm: the experiments of 1975 and 1976     

Richter B 《Science (New York, N.Y.)》1977,196(4296):1286-1297

  相似文献   

Macroeconomics of disease prevention in the United States   总被引：2，自引：0，他引：2  

G B Gori  B J Richter 《Science (New York, N.Y.)》1978,200(4346):1124-1130

  相似文献