Late Cambrian acritarchs from the Santa Rosita Formation: implications for the Cambrian-Ordovician boundary in the eastern Cordillera of northwest Argentina

Marine phytoplankton from the Late Cambrian are described for the first time in the Eastern Cordillera of northwest Argentina. The acritarch assemblage was recovered from an offshore lower mudstone unit towards the base of the Casa Colorada Member (Santa Rosita Formation) in the Quebrada de Moya section, Jujuy Province. The presence of Vulcanisphaera africana, Saharidia fragilis, Granomarginata squamacea and Celtiberium sp. 1, together with the absence of Tremadocian acritarch species and the scarcity and low diversity of diacrodian acritarchs suggest an age not younger than Late Cambrian for this acritarch assemblage. This ageassignment is also supported by stratigraphic information and regional correlations.Fil: Rubinstein, Claudia Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Mangano, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Correlación Geológica. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Departamento de Geología. Cátedra Geología Estructural. Instituto Superior de Correlación Geológica; ArgentinaFil: Buatois, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Correlación Geológica. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Departamento de Geología. Cátedra Geología Estructural. Instituto Superior de Correlación Geológica; Argentin

Analysis of North Sea offshore wind power variability

This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms, and this total production is analyzed to identify the largest aggregated hourly power variations. Based on publicly available information, a simplified representation of the coastal power grid is built for the countries bordering the North Sea. Wind farms less than 60 km from shore are connected radially to the mainland, while the rest are connected to a hypothetical offshore HVDC (High-Voltage Direct Current) power grid, designed such that wind curtailment does not exceed 1% of production. Loads and conventional power plants by technology and associated cost curves are computed for the various national power systems, based on 2030 projections. Using the MATLAB-based MATPOWER toolbox, the hourly optimal power flow for this regional hybrid AC/DC grid is computed for high, low and medium years from the meso-scale database. The largest net load variations are evaluated per market area and related to the extra load-following reserves that may be needed from conventional generators.Parts of this work were funded by Agentschap.NL, the Netherlands, now RVO.nl (Rijksdienst voor Ondernemend Nederland [25], under the project North Sea Transnational Grid (NSTG). The NSTG project is a cooperation between Delft University of Technology and the Energy Research Center of the Netherlands

Discussion and reply : the Cambrian System in Northwestern Argentina : stratigraphical and palaeontological framework Discussion

As part of the Special Issue on "Advances in the knowledge of the Cambrian System" edited by himself, Aceñolaza (2003) attempted to summarize present knowledge on the Cambrian of northwest Argentina. Althoughhe is congratulated for tackling such a complex topic, wewould like to take advantage of Geologica Acta as aforum for discussion to address some issues that remain unclear and to advance alternative ideas, providing pertinent additional literature. We will discuss these aspects by referring to the three most important stratigraphic units thatinclude Cambrian rocks in northwest Argentina, the Puncoviscana Formation, the Mesón Group and the Santa Rosita Formation. Aspects addressed are tectonic setting, stratigraphic relations, age and depositional environment. Trace fossil data included in the appendix are briefly reviewed

User-assisted intrinsic images

For many computational photography applications, the lighting and materials in the scene are critical pieces of information. We seek to obtain intrinsic images, which decompose a photo into the product of an illumination component that represents lighting effects and a reflectance component that is the color of the observed material. This is an under-constrained problem and automatic methods are challenged by complex natural images. We describe a new approach that enables users to guide an optimization with simple indications such as regions of constant reflectance or illumination. Based on a simple assumption on local reflectance distributions, we derive a new propagation energy that enables a closed form solution using linear least-squares. We achieve fast performance by introducing a novel downsampling that preserves local color distributions. We demonstrate intrinsic image decomposition on a variety of images and show applications.National Science Foundation (U.S.) (NSF CAREER award 0447561)Institut national de recherche en informatique et en automatique (France) (Associate Research Team “Flexible Rendering”)Microsoft Research (New Faculty Fellowship)Alfred P. Sloan Foundation (Research Fellowship)Quanta Computer, Inc. (MIT-Quanta T Party

Biofilm Harvesters in Coastal Settings of the Early Palaeozoic

The ichnogenera Syringomorpha and Daedalus are here interpreted as products of infaunal biofilm harvesters. This study investigated: (1) Syringomorpha nilssoni and Syringomorpha isp. from the Cambrian Series 2‐Miaolingian Campanario Formation, northwest Argentina; and (2) Daedalus halli from the Floian Grès et Schistes de la Cluse de l’Orb Formation, Montagne Noire, France. Syringomorpha nilssoni occurs in sandy to mixed intertidal to lower shoreface deposits, whereas Syringomorpha isp. in the lower intertidal zone. Daedalus halli occurs in a lagoon and intertidal to lower shoreface sands of a barrier island. Syringomorpha and Daedalus comprise a vertical J‐shaped causative burrow and deep spreite. These ichnotaxa form monospecific assemblages (bioturbation index BI = 3–5) in quartzose medium‐ to fine‐grained sandstone, recording colonization in high‐energy tide‐and wave‐dominated settings. Lower abundances (BI = 1–2) are observed in silty sandstone. The abundance of both ichnogenera in mature sandstone is inconsistent with a classic deposit‐feeding strategy because ‘clean’ sediments are commonly impoverished of organic detritus, this being particularly true in Cambro‐Ordovician littoral settings lacking terrestrial plant detritus. Based on morphology, host sediment properties and comparison with modern structures, such those produced on intertidal and shallow subtidal setting by Arenicola marina and Paraonis fulgens, it is suggested that the diet of Syringomorpha and Daedalus producers may have consisted of biofilms colonising sand grains, associated eukaryotic microbes, and possibly meiofauna. Whereas Syringomorpha is a product of the Cambrian explosion, Daedalus is associated with the Ordovician Radiation. In contrast to most ichnotaxa, which display long temporal ranges, these two ichnogenera are restricted to the Cambrian and Ordovician‐Silurian, respectively. The underlying reasons for the relatively restricted stratigraphic ranges of these ichnotaxa are unclear, but space competition, and increased predation pressure may have played a role. The feeding strategy of the Daedalus and Syringomorpha producers was less efficient than suspension feeding and passive predation, trophic types epitomized by the dominant macroinfauna that persisted in water‐agitated nearshore sands during the rest of the Phanerozoic

Etudes comportementales et neurobiologiques de l'apprentissage visuel chez l'abeille (Apis mellifera) en réalité virtuelle

Les abeilles en libre vol montrent des capacités cognitives visuelles remarquables mais les bases neurales sous-jacentes ne peuvent pas être étudiées chez des insectes en vol. À l'inverse, le cerveau des abeilles immobilisées est accessible mais ne permet pas d'explorer l'apprentissage visuel. Pour dépasser cette limite, notre objectif a été d'établir un dispositif de réalité virtuelle pour pouvoir tester l'apprentissage visuel sur des abeilles attachées. Dans un premier temps, les abeilles ont été testées sur leur capacité à discriminer des couleurs en s'appuyant sur les renforcements positifs ou négatifs qui leur étaient associés. Ces expériences ont permis de mettre en évidence le rôle de la vision active dans la réalité virtuelle et l'importance de la phototaxie dans ce type de système. Grâce à ce dispositif, un apprentissage non élémentaire en réalité virtuelle, le patterning négatif, a été mis en place. Ainsi il a été montré que les abeilles étaient capables de résoudre cette tache en réalité virtuelle malgré sa complexité. Enfin, en s'appuyant sur le protocole de discrimination de couleurs, l'activation du cerveau a été étudiée au cours d'un test de mémoire des couleurs en analysant l'expression de gènes considérés comme des marqueurs de l'activité neurale. Les résultats de cette thèse, fournissant deux protocoles de réalité virtuelle solides pour étudier les apprentissages visuels élémentaires et non élémentaires, constituent une avancée considérable vers la possibilité de comprendre les bases neurales sous-jacentes à ces apprentissages chez l'abeille qu'ils soient simples ou complexes.Free flying bees are known for their impressive visual cognition abilities, but the neural bases underlying those are poorly studied because of the difficulty to explore the brain in a flying insect. Conversely, it is possible to have access to the brain with tethered bees but, until now, no studies explored visual learning. To bypass this limitation, our aim was to establish a virtual reality device to test visual learning in tethered bees. First, bees were tested for their abilities to learn to discriminate colors according to the reinforcement associated to each of them. These experiments allowed to highlight the role of the active vision in virtual reality and the importance of phototaxis in this kind of device. Driven by these good results, we explored the non- elementary visual learning in bees and, more specifically, the negative patterning. The results suggest that bees were able to resolve this task in virtual reality despite its complexity. Finally, using the protocol of color discrimination, the brain activation has been explored during a color memory recall thanks to a quantification of immediate early genes considered as neural markers. This thesis provides two solid virtual reality protocols to study elementary and non-elementary visual learning in honey bees. This constitutes a huge advance and will allow to go further towards the understanding of the neural bases of simple and complex visual learning

Traduire He-Yin Zhen, perspectives sur la circulation des idées féministes

Cet article propose la traduction inédite d’extraits de textes et articles de la théoricienne anarchiste et féministe chinoise He-Yin Zhen (1884-v.1920), ainsi que la reconstitution d’une liste complète de ses travaux. La redécouverte, la traduction et la confrontation avec ces textes posent de nombreuses questions. La traduction est-elle déjà une interprétation ? Comment rendre compte de l’histoire des termes et de leurs transformations ? Qu’ont ces textes à dire sur l’histoire du féminisme, ses théories et leurs circulations ? Que nous enseignent-ils sur la production du savoir sur l’histoire chinoise et les « études chinoises » ? La traduction peut-elle être un outil pour les luttes féministes actuelles, ou renforce-t-elle les structures coloniales du savoir ?This article proposes the unpublished translation of excerpts from texts and articles written by the Chinese anarchist and feminist theorist He-Yin Zhen (1884-v.1920), as well as an attempt to rebuild a complete list of her works. Re-discovering and translating these texts does raise many questions. Is translation already interpretation? How can we account for the history of the concepts and words she uses and their transformations throughout time? What do these texts have to say about the history of feminism ? What do they teach us about knowledge production on Chinese history or in the area of « Chinese Studies » ? Can translation be a tool for the ongoing feminist struggles, or does it reinforce the colonial structures of knowledge

Sedimentology and Ichnology of Paleozoic Estuarine and Shoreface Reservoirs, Morrow Sandstone, Lower Pennsylvanian of Southwest Kansas, USA

Integration of facies and trace-fossil evidence tests and refines depositional models constructed solely on the basis of physical sedimentology. In recent years, the petroleum industry has increasingly used trace-fossil analysis of cores as an aid in reservoir characterization. In particular, ichnologic data have been instrumental in the recognition of estuarine deposits and their distinction from open-marine facies (e.g., MacEachern and Pemberton, 1994). Previous ichnologic analyses of cores, however, have concentrated on post-Paleozoic reservoirs (e.g., Bockelie, 1991; Pemberton, 1992; Taylor and Gawthorpe, 1993; Howell et al., 1996; Martin and Pollard, 1996; MacEachern and Pemberton, 1997). The present study represents one of the first attempts to apply trace-fossil analysis to cores from Paleozoic reservoirs. The Lower Pennsylvanian Morrow Sandstone contains oil and gas reservoirs in a wide variety of shallow and marginal-marine depositional environments. Delta-front, shoreface, and estuarine valley-fill reservoir sandstones are encased in offshore and estuarine mudstones (Sonnenberg, 1985; Krystinik and Blakeney, 1990; Sonnenberg et al., 1990; Wheeler et al., 1990). An integrated stratigraphic, sedimentologic, and ichnologic study provides a more accurate characterization of reservoir facies and geometry. This study allows distinction between marine-shoreface and estuarine valley-fill sandstones from four cores of the lower Morrow in southwestern Kansas. Core analysis subsequently was integrated with well-log information. Previous studies have emphasized the presence of estuarine valley-fills in the upper Morrow (Wheeler et al., 1990). Our integrated approach extends the estuarine valley interpretation into the lower Morrow. Within the midcontinent, trace fossils are useful in distinguishing different facies in estuarine incised valleys and marine shorefaces. Detailed study of biogenic structures provides high-resolution information to solve problems in facies, stratigraphic, and reservoir modeling. In some cases, they represent the only evidence available to develop a reasonable picture of depositional conditions and to estimate reservoir heterogeneity. The present study provides a detailed analysis of the sedimentary facies, documents the associated trace fossils, and illustrates how trace fossils are used to refine environmental interpretations of the lower Morrow sandstone reservoirs

Le sacré et la représentation de la femme dans le théâtre et la peinture symbolistes

L’art symboliste pictural ou théâtral qui s’est développé à la fin du dix-neuvième siècle est habité par le sacré, que celui-ci se manifeste sous la forme du spirituel, du religieux ou sous toute autre forme (spiritisme, occultisme, mysticisme). Quelle que soit sa forme, le sacré est pour tous les symbolistes lié à l’art. Leurs recherches formelles, multiples et variées, tendent toutes à faire surgir l’invisible du visible. Or toutes voient l’émergence, dans les œuvres, de la représentation de la femme, qui dès lors devient intimement liée au «symbolisme». En véhiculant le sacré, la femme devient le symbole des idées des artistes sur leur art, voire le symbole du rapport de l’artiste à son art. Ainsi la thèse étudie la femme dans son rapport aux idées et à l’esthétique propres à chaque artiste, dans son interrelation avec l’art et le sacré et les études détaillées des œuvres dramatiques et picturales visent à montrer la variété et la complexité de ses représentations. En même temps, cette recherche est une étude d’ensemble concernant les relations entre le théâtre et la peinture dans la période fin-de-siècle, abordées non pas de l’extérieur, mais de l’intérieur (c’est-à-dire par les caractéristiques propres des œuvres), dans le cadre de la théorie de l’image ouverte, telle qu’elle a été développée par Georges Didi-Huberman. Finalement, que la forme d’expression artistique soit celle de l’art dramatique ou celle de l’art pictural, la femme n’est dans les œuvres que la manifestation d’une réflexion esthétique qui est aussi une réflexion philosophique, elle est le lieu de rencontre entre le Moi et l’Autre à partir duquel s’origine l’œuvre.Symbolist art, be it pictorial or theatrical, which developed in the late nineteenth century was filled with sacredness, whatever its form: spiritual, religious or any other (spiritualism, occultism, mysticism). However in all its forms, sacredness is for all symbolists linked to Art. Formal research by symbolists, which is numerous and diverse, all tends to make the invisible visible. However all symbolists formal research saw in the works the emergence of the representation of women, which therefore becomes intimately linked to the "symbolism". By conveying sacredness, woman becomes the symbol of the ideas of the artists on their Art; even the symbol of the relationship of the artist to his Art. Thus this thesis studies woman in its relationship to the ideas and aesthetics of each artist, in its interrelationship with Art and the sacredness. The detailed studies of drama and paintings aim to show the variety and complexity of its representations. At the same time, this research is a global study on the relationship between theatre and painting in the end-of-century period, approached not from outside but from within (i.e. by the characteristics of works), as part of the theory of the open image developed by Georges Didi-Huberman. Finally, whatever the form of artistic expression – drama or painting – woman is only in the works, the manifestation of aesthetic reflection that is also a philosophical reflection, situated at the crossroads between the Ego and the Other, from which the work originates