4,012 research outputs found
Fungal phytopathogens encode functional homologues of plant rapid alkalinisation factor (RALF) peptides
No full textIn this paper we describe the presence of genes encoding close homologues of an endogenous plant peptide, rapid alkalinisation factor (RALF), within the genomes of 26 species of phytopathogenic fungi. Members of the RALF family are key growth factors in plants, and the sequence of the RALF active region is well conserved between the plant and fungal proteins. RALF1-like sequences were observed in most cases; however, RALF27-like sequences were present in the Sphaerulina musiva and Septoria populicola genomes. These two species are pathogens of poplar and interestingly, the closest relative to their respective RALF genes is a poplar RALF27-like sequence. RALF peptides control cellular expansion during plant development, but were originally defined based on their ability to induce rapid alkalinisation in tobacco cell cultures. To test whether the fungal RALF peptides were biologically active in plants, we synthesized RALF peptides corresponding to those encoded by two sequenced genomes of the tomato pathogen Fusarium oxysporum f. sp. lycopersici. One of these peptides inhibited the growth of tomato seedlings and elicited responses in tomato and Nicotiana benthamiana typical of endogenous plant RALF peptides (ROS burst, induced alkalinisation and MAP kinas activation). Gene expression analysis confirmed that a RALF-encoding gene in Fusarium oxysporum f. sp. lycopersici was expressed during infection on tomato. However a subsequent reverse genetics approach revealed that the RALF peptide was not required by Fusarium oxysporum f. sp. lycopersici for infection on tomato roots. This study has demonstrated the presence of functionally active RALF peptides encoded within phytopathogens that harbour an as yet undetermined role in the plant-pathogen interactions. This article is protected by copyright. All rights reserved.The authors would like to thank Dr Markus Albert for technical advice on
the alkalinization assay. PSS is an Australian Research Council Future
Fellow (FT110100698). BS is supported by an Australian Research
Council Discovery Early Career Award (DE150101897). ET is supported
by an Australian Postgraduate Award and a Grains Research and
Development Corporation Scholarship
Gulf Stream intensification after the early Pliocene shoaling of the Central American Seaway
No full textThe shoaling of the Central American Seaway (CAS) around 4.6 Ma (million years ago) is thought to have enhanced the Gulf Stream, strengthening the Atlantic Meridional Overturning Circulation and potentially influencing the evolution of Pliocene climate. Paleoclimate records indicate a buildup of heat and salt in the Caribbean and changes in the formation of North Atlantic Deep Water (NADW) associated with a major step in the shoaling of the CAS at 4.6 Ma. However, so far, direct evidence supporting an intensification of the Gulf Stream is scarce. Here we report new North Atlantic early Pliocene (5.3–3.9 Ma) records of sea surface temperature (SST) reconstructed using the UK37’ and TEX86 paleotemperature indices. Based on new sediment trap measurements near the study site, we suggest that in this particular region, the two paleothermometers record SST during different seasons: spring for UK37’ and summer for TEX86. At 4.6 and 4.2 Ma, our results indicate substantial increases in SST and salinity during summer but not spring, pointing to a significant intensification of the Gulf Stream and its extension, the North Atlantic Current, after the shoaling of the CAS. The divergence of the UK37’ and TEX86 temperature trends in those intervals suggests that the Gulf Stream intensification contributed to the strong North Atlantic seasonality that is observed toda
Prototyp(2008), Archetyp(2009) y Antityp(2010): historieta y disidencia sexual en el ciclo bíblico de Ralf König
No full textThis paper analyzes from a sex-dissident perspective the so-called biblical series of the german comic writer and cartoonist Ralf König. From a work with comic and parodic devices in three texts, this author constructs queer interpretations of canonical bible episodes. In Prototyp(2008) the episode of Adam, Eve, God and the serpent in Eden is rewritten. In Archetyp(2009) Noah's episode and the flood. Finallyin the last volume, Antityp(2010) works with the biblical figure of Paulus (Paul) of Tarsus. This article analyze these comics to think how what may see new themes in König have a specific root in his early works.Este artículo analiza desde una perspectiva sexo-disidente lo que se puede denominar como el «ciclo bíblico»del historietista alemán Ralf König. A partir de un trabajo con dispositivos cómicos y paródicos en tres textos este autor construye (re)interpretaciones «torcidas»de episodios canónicos de la Biblia. En Prototyp(2008) se reescribe el episodio de Adán, Eva, Dios y la serpiente en el Edén. En Archetyp(2009) se retoma el episodio de Noé y el diluvio. Finalmente en el último volumen, Antityp(2010) se trabaja con la figura bíblica de Paulus (Pablo) de Tarso. Este artículo pretende analizar esas obras para pensar cómo lo que puede parecer la «aparición»de nuevos temas en König tiene una raíz específica ya en obras de sus primeras etapas
Text Mining and Gene Expression Analysis Towards Combined Interpretation of High Throughput Data
No full textMicroarrays can capture gene expression activity for thousands of genes simultaneously and thus make it possible to analyze cell physiology and disease processes on molecular level. The interpretation of microarray gene expression experiments profits from knowledge on the analyzed genes and proteins and the biochemical networks in which they play a role. The trend is towards the development of data analysis methods that integrate diverse data types. Currently, the most comprehensive biomedical knowledge source is a large repository of free text articles. Text mining makes it possible to automatically extract and use information from texts.
This thesis addresses two key aspects, biomedical text mining and gene expression data analysis, with the focus on providing high-quality methods and data that contribute to the development of integrated analysis approaches. The work is structured in three parts. Each part begins by providing the relevant background, and each chapter describes the developed methods as well as applications and results.
Part I deals with biomedical text mining:
Chapter 2 summarizes the relevant background of text mining; it describes text mining fundamentals, important text mining tasks, applications and particularities of text mining in the biomedical domain, and evaluation issues.
In Chapter 3, a method for generating high-quality gene and protein name dictionaries is described. The analysis of the generated dictionaries revealed important properties of individual nomenclatures and the used databases (Fundel and Zimmer, 2006). The dictionaries are publicly available via a Wiki, a web service, and several client applications (Szugat et al., 2005).
In Chapter 4, methods for the dictionary-based recognition of gene and protein names in texts and their mapping onto unique database identifiers are described. These methods make it possible to extract information from texts and to integrate text-derived information with data from other sources. Three named entity identification systems have been set up, two of them building upon the previously existing tool ProMiner (Hanisch et al., 2003). All of them have shown very good performance in the BioCreAtIvE challenges (Fundel et al., 2005a; Hanisch et al., 2005; Fundel and Zimmer, 2007).
In Chapter 5, a new method for relation extraction (Fundel et al., 2007) is presented. It was applied on the largest collection of biomedical literature abstracts, and thus a comprehensive network of human gene and protein relations has been generated. A classification approach (Küffner et al., 2006) can be used to specify relation types further; e. g., as activating, direct physical, or gene regulatory relation.
Part II deals with gene expression data analysis:
Gene expression data needs to be processed so that differentially expressed genes can be identified. Gene expression data processing consists of several sequential steps. Two important steps are normalization, which aims at removing systematic variances between measurements, and quantification of differential expression by p-value and fold change determination. Numerous methods exist for these tasks.
Chapter 6 describes the relevant background of gene expression data analysis; it presents the biological and technical principles of microarrays and gives an overview of the most relevant data processing steps. Finally, it provides a short introduction to osteoarthritis, which is in the focus of the analyzed gene expression data sets.
In Chapter 7, quality criteria for the selection of normalization methods are described, and a method for the identification of differentially expressed genes is proposed, which is appropriate for data with large intensity variances between spots representing the same gene (Fundel et al., 2005b). Furthermore, a system is described that selects an appropriate combination of feature selection method and classifier, and thus identifies genes which lead to good classification results and show consistent behavior in different sample subgroups (Davis et al., 2006).
The analysis of several gene expression data sets dealing with osteoarthritis is described in Chapter 8. This chapter contains the biomedical analysis of relevant disease processes and distinct disease stages (Aigner et al., 2006a), and a comparison of various microarray platforms and osteoarthritis models.
Part III deals with integrated approaches and thus provides the connection between parts I and II:
Chapter 9 gives an overview of different types of integrated data analysis approaches, with a focus on approaches that integrate gene expression data with manually compiled data, large-scale networks, or text mining.
In Chapter 10, a method for the identification of genes which are consistently regulated and have a coherent literature background (Küffner et al., 2005) is described. This method indicates how gene and protein name identification and gene expression data can be integrated to return clusters which contain genes that are relevant for the respective experiment together with literature information that supports interpretation.
Finally, in Chapter 11 ideas on how the described methods can contribute to current research and possible future directions are presented
Evaluation of Intelligent Quantitative Hedge Fund Management
No full textThis paper examines an intelligent recommendation strategy implementation for managing a long short hedge fund and reports on performance during market conditions at the onset of the liquidity crisis. A hedge fund utilizes long and short trading to manage an investment portfolio consisting of allocations to cash and share equity positions. This results in a combined long short portfolio that is leveraged to obtain a potentially greater market exposure with borrowed cash from short selling and is also hedged to protect against market downturns. The paper also examines effects of parameters for fuzzy rule base specification on trading performance.Muneer Buckley, Adam Ghandar, Zbigniew Michalewicz, Ralf Zurbrueg
Are combination forecasts of S&P 500 volatility statistically superior?
No full textForecasting volatility has received a great deal of research attention, with the relative performances of econometric model based and option implied volatility forecasts often being considered. While many studies find that implied volatility is the pre-ferred approach, a number of issues remain unresolved, including the relative merit of combining forecasts and whether the relative performances of various forecasts are statistically different. By utilising recent econometric advances, this paper considers whether combination forecasts of S&P 500 volatility are statistically superior to a wide range of model based forecasts and implied volatility. It is found that a combination of model based forecasts is the dominant approach, indicating that the implied volatility cannot simply be viewed as a combination of various model based forecasts. Therefore, while often viewed as a superior volatility forecast, the implied volatility is in fact an inferior forecast of S&P 500 volatility relative to model-based forecasts. © 2007 International Institute of Forecasters
Cultural representation of sexual dissent in comics: the "desired men" of Ralf König in Der bewegte Mann
No full textEn este artículo se abordará la representación de la sexualidad disidente en una de las obras inaugurales de Ralf König, el ciclo Der bewegte Mann, constituido por dos partes publicadas en los años ochenta y que nos permiten apreciar la emergencia del autor en el mercado editorial alemán, así como sus operaciones de resistencia ante los intentos de normalización y represión por parte de la heteronormatividad.In this article, the representation of sexual dissent in German author Ralf König will be adressed. The work analize the cycle Der bewegte Mann, consisting of two parts published in the eighties and that allows us to appreciate the emergence of the author in the german publishing, as well as its operations of resistance to the attempts of normalization and repression by heteronormativity.Fil: Saxe, Facundo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales (UNLP-CONICET); Argentina
Representación cultural de la disidencia sexual en el cómic: los «hombres deseados» de Ralf König en Der bewegte Mann
No full textEn este artículo se abordará la representación de la sexualidad disidente en una de las obras inaugurales de Ralf König, el ciclo Der bewegte Mann, constituido por dos partes publicadas en los años ochenta y que nos permiten apreciar la emergencia del autor en el mercado editorial alemán, así como sus operaciones de resistencia ante los intentos de normalización y represión por parte de la heteronormatividad.In this article, the representation of sexual dissent in German author Ralf König will be adressed. The work analize the cycle Der bewegte Mann, consisting of two parts published in the eighties and that allows us to appreciate the emergence of the author in the german publishing, as well as its operations of resistance to the attempts of normalization and repression by heteronormativity.Facultad de Humanidades y Ciencias de la Educació
Learning multi-criteria fuzzy rule based decision models for hedge fund management
No full textAdam Ghandar, Zbigniew Michalewicz and Ralf Zurbruegghttp://www.smartframe.de/mic09/Home.htm
Sexuellen Dissidenz and Comic im Werk von Ralf König
No full textRalf König es un autor de importancia innegable para la historieta alemana desde los años ochenta al presente. El abordaje programático y sistemático de la sexualidad disidente en sus vertientes más subversivas convierten la obra de König en un conjunto de textos culturales que constituyen una suerte de "historias culturales" de los devenires de la disidencia sexual en las últimas tres décadas en el contexto europeo. Este artículo analiza dos obras de Ralf König (Kondom des Grauens, 1987; Bis auf die Knochen, 1990) que constituyen un ciclo que permiten pensar el diálogo que establece la obra de König con la crisis del VIH-Sida, la pornografía gay, la violencia y discriminación sobre las sexualidades disidentes, la influencia del movimiento queer y el colectivo LGBTIQ norteamericano en Alemania, entre otras cuestiones.Ralf König has been an author of an undeniable importance for the German comic since the 1980s. The programmatic and systematic approach to dissident sexuality in its most subversive aspects makes König's work a set of cultural texts that stand as some sort of "cultural histories" of the progressions of sexual dissidence in the last three decades in the European context. This article analyzes two works by Ralf König (Kondom des Grauens, 1987; Bis auf die Knochen, 1990) which constitute a cycle that allows us to ponder on the dialogue established by König's works with the HIV-AIDS crisis, gay pornography, violence and discrimination towards dissident sexualities, the influence of the queer movement and the American LGBTIQ collective in Germany, among other issues.Facultad de Humanidades y Ciencias de la Educació
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