The versatility of the one‐dimensional discrete wavelet analysis combined with wavelet and Burg extensions for forecasting financial times series with distinctive properties is illustrated with market data. Any time series of financial assets may be decomposed into simpler signals called approximations and details in the framework of the one‐dimensional discrete wavelet analysis. The simplified signals are recomposed after extension. The final output is the forecasted time series which is compared to observed data. Results show the pertinence of adding spectrum analysis to the battery of tools used by econometricians and quantitative analysts for the forecast of economic or financial time series.
In response to predation pressure, some insects have developed spectacular plant mimicry strategies (homomorphy), involving important changes in their morphology. The fossil record of plant mimicry provides clues to the importance of predation pressure in the deep past. Surprisingly, to date, the oldest confirmed records of insect leaf mimicry are Mesozoic. Here we document a crucial step in the story of adaptive responses to predation by describing a leaf-mimicking katydid from the Middle Permian. Our morphometric analysis demonstrates that leaf-mimicking wings of katydids can be morphologically characterized in a non-arbitrary manner and shows that the new genus and species Permotettigonia gallica developed a mimicking pattern of forewings very similar to those of the modern leaf-like katydids. Our finding suggests that predation pressure was already high enough during the Permian to favour investment in leaf mimicry.
RÉSUMÉA l'âge du Bronze ancien en Europe occidentale, l'augmentation drastique de la production de cuivre est très peu documentée au niveau des activités minières et métallurgiques de transformation. Dans ce contexte, le gisement minier et métallurgique de Saint-Véran, Hautes-Alpes constitue un témoin privilégié de la production de masse à la fin du 3 e millénaire, puisqu'aux travaux miniers rendant compte d'une exploitation à grande échelle, avec une production de près de sept tonnes de cuivre par an, plusieurs sites de métallurgie extractive ont pu être associés. Depuis près de vingt ans, plusieurs équipes dont celle rassemblant les présents auteurs ont mené ou mènent des recherches pour tenter de documenter le site et son activité. L'objectif de cet article est de présenter l'état de nos connaissances du gisement au jour d'aujourd'hui. Les résultats principaux sont la mise en évidence et la quantification de l'activité de production de masse. De plus, une première description de l'organisation de la production a pu être donnée, où sont mis en lumière les phasages entre activité minière et mé-tallurgiques, ainsi que les techniques métallurgiques innovantes mises en place. Le gisement révèle un éclate-ment très marqué de l'activité métallurgique dans l'espace qui ne laisse pas d'interroger. De même, la question de la destination de la production reste entièrement posée. Par ailleurs, les moteurs d'une telle implantation en territoire de haute montagne ont commencé d'être identifiés. Ainsi sont évoqués, pour les seuls déterminis-mes naturels, aussi bien la minéralisation particulière du gisement que l'évolution du climat.
RESUMEN
Purpose
The purpose of this paper is to present forecasts of fossil fuels prices until 2030 with spectral analysis to provide a clearer picture of this energy sector.
Design/methodology/approach
Fossil fuels prices time series are decomposed in simpler signals called approximations and details in the framework of the one-dimensional discrete wavelet analysis. The simplified signals are recomposed after Burg extension.
Findings
In 2019-2030 average price forecasts of: West Texas intermediate (WTI) oil ($58.67) is above its 1986-2030 long-term mean of $47.83; and coal ($81.01) is above its 1980-2030 long-term mean of $60.98. On the contrary, 2019-2030 average of price forecasts of: Henry Hub natural gas ($3.66) is below its 1997-2030 long-term mean of $4; heating oil ($0.64) is below its 1986-2030 long-term mean of $1.16; propane ($0.26) is below its 1992-2030 long-term mean of $0.66; and regular gasoline ($1.45) is below its 2003-2030 long-term mean of $1.87.
Originality/value
Fossil fuels prices projections may relieve participants of WTI oil and coal markets but worry participants of Henry Hub, heating oil, propane and regular gasoline markets including countries whose economy is tied to energy prices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.