1,720,956 research outputs found
Breeding for a reduced glucosinolate content in the green mass of rapeseed to improve its suitability for biogas production
No full textGenetic variation in leaf and stem glucosinolates in resynthesized lines of winter rapeseed (Brassica napus L.)
Full text linkGlucosinolates are secondary components characteristic for the Brassicaceae with complex biological functions. Glucosinolates in the seeds are anti-nutritive when feeding animals and their inheritance have been extensively investigated. Much less is known about the genetics of glucosinolates in leaves and stems, which may attract some insects, while repelling others. They may also inhibit bacterial processes of importance when using green biomass for the production of biogas. The objective of this study was to analyse the genetic variation of total and individual glucosinolates in the green material of rapeseed. For this 28 resynthesized winter rapeseed lines were tested at two locations. There was a large variation in leaf glucosinolate content between 0.10 and 4.75 mu mol/g dry matter. The predominant leaf glucosinolates are the alkenyle glucosinolates progoitrin, gluconapin and glucobrassicanapin. The line R53 is exceptional, while combining a relative high content of the indole glucosinolate glucobrassicin with low alkenyle glucosinolates in the leaves. The total glucosinolate concentration in the stems and leaves is not correlated with the seed glucosinolate concentrations. Heritabilities are above hA(2)A = 0.60 for progoitrin, hA(2)A = 0.65 for gluconapin, hA(2)A = 0.30 for glucobrassicanapin and hA(2)A = 0.52 for total glucosinolate content in the leaves. In conclusion, resynthesized rapeseed is an important genetic resource to modify the leaf glucosinolate content and composition of rapeseed.Deutsche Bundesstiftung Umwelt (DBU
Tracing shifting cultivation in the Nam Ton watershed (Lao PDR) by multispectral image-to-image change detection techniques with statistical verification
No full textWhen looking for critical areas in the context of erosion and degradation in Laos, the regions that are affected by shifting cultivation are prior and most distinct visual. Up to now the distribution and extent of these areas is still unknown. This makes it unclear whether the extent and distribution of this practice has a cause in the further depletion of Laos natural forest resources. In order to find more accurate figures, the following study compares different satellite remote sensing techniques that monitor shifting cultivation. An unsupervised classification method of a tasseled cap transformation has a best overall accuracy of 84.5% in comparison with unsupervised classification according to principal components analysis (81.9%) and vegetation indexing (71.4%). It is concluded that the applied techniques are very useful applications in the monitoring of shifting cultivation in the catchments in Laos. This is due to their fast delivery of timely and accurate relevant information
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Züchtung auf einen niedrigen Glucosinolatgehalt in Rapsblättern zur Verbesserung der Eignung zur Biogasgewinnung
Full text linkIn den letzten Jahren hat die Erzeugung von Biogas aus Energiepflanzen kontinuierlich zugenommen. Die Biogasgewinnung ist ein wichtiger Beitrag zur nachhaltigen Erzeugung von erneuerbarer Energie. Ein Vorteil der Biogaserzeugung ist auch dass die gesamte Wertschöpfungskette allein in der Hand des Landwirts liegt, während z.B. bei der Erzeugung von Biodiesel die Landwirtschaft nur als Rohstofflieferant fungiert. Biogas wird heute überwiegend aus Maissilage gewonnen, Mais produziert zwar eine hohe Biomasse, nutzt aber für sein Wachstum nur die wärmere Jahreszeit ab Mai. Daher sollte der Maisanbau kombiniert werden mit dem Anbau einer Vorfrucht, die bei niedrigen Temperaturen bereits hohe Biomasse produziert. Eine solche Fruchtart ist der Raps, der bei der Blüte Anfang Mai bereits fast seine maximale Biomasse erreicht hat. Raps bietet die Möglichkeit in einen Zweikultur-Nutzungssystem angebaut zu werden, wobei Raps zur Vollblüte geerntet wird um anschließend eine andere zweite Kultur auszusäen. In diesem Fall ist bei Raps eine hohe vegetative Masse zur Blüte das Hauptziel, während die Samenqualität und auch viele Krankheiten keine Rolle mehr spielen. Für eine verbesserte Biogasnutzung steht eine optimale Zusammensetzung der Pflanzenmasse leider noch ganz am Anfang. Durch Änderungen in den pflanzlichen Inhaltstoffen kann ein effizienter nachwachsender Rohstoff erzogen werden. Die heutigen 00-Rapsgenotypen haben einen niedrigen Gehalt an Glucosinolaten in den Rapskörnern, aber nicht notwendigerweise auch in den Blättern und Stängeln. Wenn Raps als Rohstofff für die Biogasproduktion verwendet wird, könnte ein hoher GSL-Gehalt in den Blättern von Nachteil sein. Glucosinolate bilden nämlich Abbauprodukte, die toxisch für Mikroorganismen wie Bakterien sein können. Derzeit gibt es keine Untersuchungen zum Zusammenhang zwischen GSL Gehalt in Blättern und Stängeln und der Ausbeute an Biogas. Im Rahmen der Dissertation soll der Zusammenhang zwischen GSL-Gehalt in der Rapsbiomasse und der Eignung zur Biogaserzeugung untersucht werden.Brassica napus L., a plant that belongs to the Brassicaceae family is one of the main oil crops. Inside its seeds glucosinolates appear to be the main secondary glycoside, sugar containing component with sulfur containing bindings. Plant breeders have tried to lower the glucosinolate levels of seeds of rapeseed so that the high-protein seed meal remaining after oil extraction can be used as animal food. Products such as the nitriles and isothiocyanates are toxic components. Some of the glucosinolate types or alkenyles have negative effects in animal nutrition such as progoitrin. Very little is known about the function and roles of glucosinolates in the vegetative tissue of flowering winter rapeseed. The decomposition products are possibly inhibiting for bacteria in fermentation processes, caused by the very reactive side chains, released after cleavage with the myrosinase enzyme. The main objectives were to explore and define the genetic basis of the synthesis of glucosinolates in the green matter of oilseed rape and their effect on biogas production, to investigate the genetic variation of the glucosinolate contents and pattern in the vegetative tissue in classical breeding material and resynthesized rapeseed lines, to acquire information that determines the influence of the glucosinolate content and pattern in the green matter on the biogas production and finally to develop and characterize a quantitative trait loci map based on a mapping population from a cross. Causes of genetic variation are diverse, from so called mutations towards differences in chromosome number, whether this genetic variation is potentially available for certain secondary components such as the glucosinolates. More recently developed varieties with low glucosinolate levels in seeds but high glucosinolate levels in leaves are more resistant to pests and still provide a protein-rich seed residue for animal feeding. Winter rapeseed resynthesized parents and testcrosses with high biomass yielding lines were tested under different environments. Besides this a double haploid population from a cross between an exotic line (Gaoyou) and a cultivar were grown and analyzed for their glucosinolate content. These alternative crosses are made to find out more about differences in essential acting key genes that reveal the sequences behind exotic lines competing and interfering with local breeding forms. The glucosinolate content within the leaves does not correlate with the seed glucosinolates; also there is no correlation between methane, leaf and stem glucosinolates. Attention is focused on the leaf glucosinolates to identify those quantitative trait loci, which are situated in the genome and which are responsible for the glucosinolate content within the leaves. The determination of genetic variation of leaf, stem and seed glucosinolates in resynthesized winter rapeseed lines is a rather exceptional step in plant genomics. Although this study does not go into detail in the molecular level, a small jumping-leap is taken when the location of the traits is estimated. Further genetic studies are necessary to develop appropriate breeding strategies to reduce or increase leaf, stem and seed glucosinolates in winter rapeseed lines. Segregating populations of winter rapeseed lines should be tested in the future for their glucosinolate content in the leaves, stems and seeds. The polymorphisms for the occurrence of leaf stem and seed glucosinolates might be explained by their phenotypical differences, but also by the different functioning of these specific plant parts. Whether the number of genes involved in leaf glucosinolates is different from those involved in the functioning of the seed glucosinolates is not known. The higher the genetic variation for the resulting winter rapeseed breeding lines however, the better their persistence in different environments, where for example insect resistance is required
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