2,828 research outputs found
Creating short-term stockmarket trading strategies using artificial neural networks:A case study
Abstract â Developing short-term stockmarket trading systems is a complex process, as there is a great deal of random noise present in the time series data of individual securities. The primary difficulty in training neural networks to identify return expectations is to find variables to help identify the signal present in the data. In this paper, the authors follow the previously published Vanstone and Finnie methodology. They develop a successful neural network, and demonstrate its effectiveness as the core element of a financially viable trading system. Index Termsâstockmarket trading, neural networks, trading system
Modelling momentum winner/loser asymmetry: the sources of winner and loser returns in the ASX200 and S&P500
Applying and Extending the Sustainable Value Method related to Agriculture â an Overview
Sustainable Value is a method to measure the contribution of an economic entity, such as a farm or the entire agricultural sector, towards the sustainability (sustainable development) of a region, a country or on a global scale. A positive sustainable value is created once resources are used more efficiently than by a benchmark. It shows the excess return that is created or lost by the use of economic, environmental and social resources by an economic entity relative to a benchmark. The purpose of this paper is to give an overview on the characteristics and requirements of the SV and to provide information on (a) possible applications and (b) extensions of the SV method related to the agricultural sector. A particular emphasis is put on the choice of sustainability indicators (resource figures, welfare figure) to be included, the generic steps of SV calculation, the meaning of weighting and aggregation in the SV, the role of the Return-to-Cost Ratio in taking farm size into consideration, and the interpretation and communication of the results of an agriculture-related SV assessment. After sketching out possible extensions and variations of the SV method, the paper closes with a summary of those aspects to keep in mind when applying the SV to agriculture.sustainability contributions, value, measurement, Environmental Economics and Policy,
Environmental Shareholder Value Matrix. Konzeption, Anwendung und Berechnung
Der Zusammenhang zwischen Umweltmanagement und Shareholder Value ist in den letzten Jahren Thema einer Vielzahl von Publikationen gewesen. Dass gutes Umweltmanagement grundsĂ€tzlich auch Shareholder Value schaffen kann, ist heute weitgehend unbestritten. Es wird allerdings auch deutlich, dass dies unter Praxisbedingungen hĂ€ufig nicht gelingt. Hier setzt diese Studie an. Sie stellt mit der Environmental Shareholder Value Matrix ein neues Analysetool vor. Die Environmental Shareholder Value Matrix untersucht systematisch den Einfluss, den UmweltmanagementmaĂnahmen auf die Werttreiber des Shareholder Value haben. Hierdurch wird deutlich, ob und wie das Umweltmanagement Shareholder Value schafft. Die Studie zeigt auĂerdem, wie der Beitrag des Umweltmanagements zum Shareholder Value berechnet werden kann. Hierbei wird eine neuartige Berechnungsweise vorgestellt. Diese neue Berechnungsweise erhöht die Transparenz der Berechnungund zeigt beispielsweise das maximal erzielbare Potenzial eines Umweltrisikomanagements auf.Shareholder Value, Environmental Management, Environmental Shareholder Value
Conservation of functional domains and limited heterogeneity of HIV-1 reverse transcriptase gene following vertical transmission
BACKGROUND: The reverse transcriptase (RT) enzyme of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in the life cycle of the virus by converting the single stranded RNA genome into double stranded DNA that integrates into the host chromosome. In addition, RT is also responsible for the generation of mutations throughout the viral genome, including in its own sequences and is thus responsible for the generation of quasi-species in HIV-1-infected individuals. We therefore characterized the molecular properties of RT, including the conservation of functional motifs, degree of genetic diversity, and evolutionary dynamics from five mother-infant pairs following vertical transmission. RESULTS: The RT open reading frame was maintained with a frequency of 87.2% in five mother-infant pairs' sequences following vertical transmission. There was a low degree of viral heterogeneity and estimates of genetic diversity in mother-infant pairs' sequences. Both mothers and infants RT sequences were under positive selection pressure, as determined by the ratios of non-synonymous to synonymous substitutions. Phylogenetic analysis of 132 mother-infant RT sequences revealed distinct clusters for each mother-infant pair, suggesting that the epidemiologically linked mother-infant pairs were evolutionarily closer to each other as compared with epidemiologically unlinked mother-infant pairs. The functional domains of RT which are responsible for reverse transcription, DNA polymerization and RNase H activity were mostly conserved in the RT sequences analyzed in this study. Specifically, the active sites and domains required for primer binding, template binding, primer and template positioning and nucleotide recruitment were conserved in all mother-infant pairs' sequences. CONCLUSION: The maintenance of an intact RT open reading frame, conservation of functional domains for RT activity, preservation of several amino acid motifs in epidemiologically linked mother-infant pairs, and a low degree of genetic variability following vertical transmission is consistent with an indispensable role of RT in HIV-1 replication in infected mother-infant pairs
Global Constructive Optimization of Vascular Systems
We present a framework for the construction of vascular systems based on optimality principles of theoretical physiology. Given the position and flow distribution of end points of a vascular system, we construct the topology and positions of internal nodes to complete the vascular system in a realistic manner. Optimization is driven by intravascular volume minimization with constraints derived from physiological principles. Direct optimization of a vascular system, including topological changes, is used instead of simulating vessel growth. A good initial topology is found by extracting key information from a previously optimized model with less detail. This technique is used iteratively in a multi-level approach to create a globally optimized vascular system. Most of this work was completed at Fraunhofer MeVis during the summer of 2004
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