A trend test for the analysis of multiple paternity     

Markus?Neuh?userEmail author  Bernd?Leisler  Ludwig?A.?Hothorn 《Journal of Agricultural, Biological & Environmental Statistics》2003,8(1):29-35

The aquatic warbler, Acrocephalus paludicola, is one of a few species in which nestlings from a single nest can be sired by up to four different fathers. Data from a DNA fingerprinting study suggest that there is a trend: the larger the number of fathers in a brood the larger is the number of nestlings. However, the number of young within a single nest cannot be smaller than the number of fathers. This restriction causes an inherent trend and, consequently, can lead to a false-positive trend test result. For this nonstandard situation, we propose a trend test that differentiates between the inherent trend and a “real” trend, that is, a larger brood size through multiple paternity. Using DNA fingerprinting data, we performed a randomization test using the proposed new trend test statistic and obtained a significant result (P=0.047). This indicates that a larger number of fathers per brood is associated with a larger brood size. In addition, we consider an umbrella alternative, that is, a downturn in effect may occur after the optimal number of fathers per brood is exceeded. An appropriate test for this alternative also leads to a significance (P=0.011).  相似文献   

Selection for <Emphasis Type="Italic">Phytophthora</Emphasis> field resistance in the F<Subscript>2</Subscript> generation of organic outdoor tomatoes     

Bernd Horneburg  Heiko C. Becker 《Euphytica》2011,180(3):357-367

Tomatoes are the most important vegetable, globally as well as in Germany. Outdoor tomato production is seriously impaired due to increasing infections with evolving late blight (Phytophthora infestans) populations. Within organic agriculture, research is being conducted to develop regionally adapted and open pollinated cultivars of outdoor tomatoes with late blight field resistance. In the present experiment, three crosses, including wild, cocktail, and beefsteak tomatoes, were selected for field resistance against late blight in F₂ at one location per cross. The comparison of positive and negative selection in F₃ revealed the selection of single F₂ plants to be efficient in all three crosses. F₂ selection has proved to be a robust and efficient tool for breeding programs. The correlated response to selection in other traits, including yield, fruit weight, days to maturity, harvest period, and plant height, depended on the cross. It was evident that selection for desired traits combined with field resistance against late blight is promising, even in wide crosses. The most undesired attribute of wild tomatoes is the formation of shoots on leaves and in inflorescences. No correlation was observed between field resistance and shoot formation, allowing the selection of genotypes with improved field resistance and yield, but without morphological disadvantages.  相似文献   

Coarse particulate organic matter is the primary source of mineral N in the topsoil of three beech forests     

Bernd Zeller  Etienne Dambrine 《Soil biology & biochemistry》2011,43(3):542-550

Forest soils contain a variable amount of organic N roughly repartitioned among particles of different size, microbial biomass and associated with mineral compounds. All pools are alimented by annual litter fall as main input of organic N to the forest floor. Litter N is further subject to mineralization/stabilization recognized as the crucial process for the turnover of litter N. Although it is well documented that different soil types have different soil N stocks, it is presently unknown how different soil types affect the turnover of recent litter N. Here, we compared the potential mineralization of the total soil organic N with that of recent litter-released N in three beech forests varying in their soil properties. Highly ¹⁵N-labelled beech litter was applied to stands located at Aubure, Ebrach, Collelongo, which differ in humus type, soil type and soil chemistry. After 4-5 years of litter decomposition, the upper 3 cm of the organo-mineral A horizon was sampled and the net N mineralization was measured over 112 days under controlled conditions. The origin of mineralized N (litter N versus soil organic N) was calculated using ¹⁵N labeling. In addition, soils were fractionated according to their particle size (>2000 μm, 200-2000 μm, 50-200 μm, <50 μm) and particulate organic matter (POM) was separated from the mineral fraction in size classes, except the <50 μm fraction. Between 41 and 69% of soil organic N was recovered as POM. Litter-released ¹⁵N was mainly to be found in the coarse POM fractions >200 μm. On a soil mass basis, N mineralization was two-fold higher at Aubure and Collelongo than at Ebrach, but, on a soil N basis, N mineralization was the lowest at Collelongo and the highest at Ebrach. On a soil N (or ¹⁵N) basis, mineralization of litter ¹⁵N was two to four-fold higher than mineralization of the average soil N. Furthermore, the δ¹⁵N of the mineral N produced was closer to that of POM than to that of the mineral-bound fraction (<50 μm). Highest rates of ¹⁵N mineralization happened in the soil with the lowest N content, and we found a negative relationship between accumulations of N in the upper A horizon and the mineralization of ¹⁵N from the litter. Our results show that mineral N is preferentially mineralized from POM in the upper organo-mineral soil irrespective of the soil chemistry and that the turnover rate of litter N is faster in soils with a low N content.  相似文献   

塔里木河下游阿拉干断面胡杨林空间分布特征及其影响因素     

塔依尔江·艾山  玉米提·哈力克  艾尔肯·艾白不拉  Bernd Cyffka  Christian Opp 《干旱区资源与环境》2011,(12):156-160

通过小尺度生态监测与遥感数据分析获取塔里木河下游荒漠河岸林现状信息,集中对阿拉干断面设立的100hm2长期监测样方内的胡杨树进行了详细的调查,对该断面胡杨林空间分布特征及其影响因素进行了分析。研究结果表明：塔里木河下游的胡杨具有伴河生长的特性;随着离河距离的增加,胡杨株数呈递减趋势;大部分胡杨主要分布在离河道200m范...  相似文献   

Bodensystematik und Bodenklassifikation Teil I: Grundbegriffe     

Christoph Albrecht  Reinhold Jahn  Bernd Huwe 《植物养料与土壤学杂志》2005,168(1):7-20

Soil systematics and classification systems Part I: Fundamentals Soil‐ordering systems are primarily based and developed on one of two underlying principles: They are either categorized according to soil‐forming processes, or the formation of categories develops by chosen parameters. This perspective has already been established in the literature, though it is often confusing as many terms are defined and applied differently. In this contribution, the various definitions of systematics, classification, taxonomy, and identification will be clearly differentiated and summarized. The core of our work is to clearly define and contrast three terms: systematics, classification, and identification. Systematics is the fundamental scientific and deductive ordering of objects into systematic units. The purpose of this approach is to organize the entire spectrum of knowledge within a discipline into a transparent and manageable form. Classification, in direct contrast to systematics, is goal‐oriented and an inductive ordering of objects. Thus, the ordering scheme consists of classes which are clearly parameterized. Identification is the ordering of new objects into an already existing systematics or classification system. Close attention is paid to both the differences and the similarities between a systematics and a classification system, especially pertaining to their practical applications. The identification requires that the category‐forming characteristics can be measured (e.g., for soil systematics, these are the soil‐forming processes and factors). Currently, it is unfortunately not feasible to objectively quantify most soil‐forming processes. Thus, most attempts at categorizing soils by systematics are hypothetical and highly subjective in nature. The resulting identification derived from the soil systematics approach is open to questions and contestable, since a graded measuring system does not yet exist to verify these determinations. In contrast, a soil‐classification system does allow an objective soil‐profile identification, although such systems are conceived pragmatically and designed for a practical purpose (e.g., not scientifically based on process intensities). Unfortunately, such a classification system cannot be applied as a universal scientific categorization system due to this method of conception. Both categorization approaches are required in soil science in order to satisfy both the practical and the scientific aspects of the field. However, substantial research must be done to complete and verify systematics. The only viable short‐term solution is through the development of a graded classification system where the categories of the system are directly derived from the current systematics approach. In the long run both the exact investigation and the detailed modeling of the soil‐forming processes are inevitable.  相似文献   

Multi-element analysis of an english peat bog soil     

Bernd Markert  Iain Thornton 《Water, air, and soil pollution》1990,49(1-2):113-123

Nineteen elements were quantitatively determined by atomic emission spectroscopy with inductively coupled plasma in peat profiles in Ringinglow Bog, Derbyshire, England. For the elements Ba, Ca, Cd, Co, Cr, Fe, La, Mn, Ni, Ti, and Zn an enrichment in the upper 5 cm of the peat bogs was found probably caused by anthropogenic influences. The elements Al, Be, Cu, and Pb showed a different distribution pattern with maximum concentration in the 5 to 15 cm layer. The elements Mg, Na, and Sr showed no enrichment in the upper 55 cm of the peat reflecting the constant input of these elements from the sea during the last few centuries. Upper parts (leaves and stems) of the plants investigated (Calluna vulgaris and Eriophorum vaginatum) only represent higher values of Pb compared with the normal element content in other plants. Compared with the results of peat profiles in a Norwegian bog, the concentrations of the comparable elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) are much higher in the English peat. Ringinglow Bog seem to be very suitable for further investigations within the scope of a global monitoring programme.  相似文献   

A conceptual framework for damage compensation schemes     

Kathleen Schwerdtner  Bernd Gruber 《Biological conservation》2007,134(3):354-360

Damage compensation schemes are widely used to mitigate human-wildlife conflicts. Despite the growing relevance of such conflicts, a theoretical framework to analyze the cost-effectiveness of damage compensation schemes is still missing. The article aims to fill this gap by proposing a conceptual framework by categorizing cost categories, which can be used to compare different types of compensation schemes. To demonstrate the value of the framework, we present an example that compares ex-post compensation and compensation in advance in the European otter (Lutra lutra) in the Upper Lusatia, Germany. We find that the two types of schemes differ widely in their transaction costs. Transaction costs themselves are closely related to the temporal and spatial distribution of damages. Therefore, the choice between the two types of compensation schemes depends on the distribution of damages, which itself depends on the species under concern. Based on this, we recommend a compensation-in-advance type of damage compensation scheme for the otter in the Upper Lusatia, Germany.  相似文献   

欧洲农机市场的开发     

BerndSeherer 《农机质量与监督》2004,(5):43-45

德国机械及制造商协会(简称VDMA)是欧洲最大的行业协会之一。VDMA成立于1892年，至今已有110多年的历史。协会的支撑是三个：网络、服务和代表会员利益，它在机械及制造行业非常活跃。VDMA是一个非赢利性的协会，拥有公司会员单位3000个，协会的工作人员达460名。VDMA作为连接会员公司与政府机构之间的桥梁，是一个自愿参加的组织，并且不接受政府  相似文献   

Santorini eruption radiocarbon dated to 1627-1600 B.C     

Friedrich WL  Kromer B  Friedrich M  Heinemeier J  Pfeiffer T  Talamo S 《Science (New York, N.Y.)》2006,312(5773):548

Precise and direct dating of the Minoan eruption of Santorini (Thera) in Greece, a global Bronze Age time marker, has been made possible by the unique find of an olive tree, buried alive in life position by the tephra (pumice and ashes) on Santorini. We applied so-called radiocarbon wiggle-matching to a carbon-14 sequence of tree-ring segments to constrain the eruption date to the range 1627-1600 B.C. with 95.4% probability. Our result is in the range of previous, less precise, and less direct results of several scientific dating methods, but it is a century earlier than the date derived from traditional Egyptian chronologies.  相似文献   

BKCa-Cav channel complexes mediate rapid and localized Ca2+-activated K+ signaling     

Berkefeld H  Sailer CA  Bildl W  Rohde V  Thumfart JO  Eble S  Klugbauer N  Reisinger E  Bischofberger J  Oliver D  Knaus HG  Schulte U  Fakler B 《Science (New York, N.Y.)》2006,314(5799):615-620

Large-conductance calcium- and voltage-activated potassium channels (BKCa) are dually activated by membrane depolarization and elevation of cytosolic calcium ions (Ca2+). Under normal cellular conditions, BKCa channel activation requires Ca2+ concentrations that typically occur in close proximity to Ca2+ sources. We show that BKCa channels affinity-purified from rat brain are assembled into macromolecular complexes with the voltage-gated calcium channels Cav1.2 (L-type), Cav2.1 (P/Q-type), and Cav2.2 (N-type). Heterologously expressed BKCa-Cav complexes reconstitute a functional "Ca2+ nanodomain" where Ca2+ influx through the Cav channel activates BKCa in the physiological voltage range with submillisecond kinetics. Complex formation with distinct Cav channels enables BKCa-mediated membrane hyperpolarization that controls neuronal firing pattern and release of hormones and transmitters in the central nervous system.  相似文献