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Description des differentes possibilites de substitution du petrole par le charbon ou la biomasse. Conclusions pour les developpements a long terme

There is a growing interest in mathematical mechanistic modelling as a promising strategy for understanding tumour progression. This approach is accompanied by a methodological change of making research, in which models help to actively generate hypotheses instead of waiting for general principles to become apparent once sufficient data are accumulated. This paper applies recent research from philosophy of science to uncover three important problems of mechanistic modelling which may compromise its mainstream application, namely: the dilemma of formal and informal descriptions, the need to express degrees of confidence and the need of an argumentation framework. We report experience and research on similar problems from software engineering and provide evidence that the solutions adopted there can be transferred to the biological domain. We hope this paper can provoke new opportunities for further and profitable interdisciplinary research in the field.

N-alkanes are ubiquitous in sedimentary samples, often exhibiting distributions with odd carbon-number predominances which are lost during the maturation of the organic matter. Distributions with even carbon-number preferences are also found although less frequently. In this paper the occurrence of striking predominance of even carbon numbered n-alkanes in the C/sub 14/-C/sub 20/ range is extended to some coal samples from seams of Nograd Basin (Northern Hungary), representing the oldest geologic samples in which this type of distribution has been described. Three coal seams of the basin were selected for the study and they had different properties and compositions. The paper describes the study and results and concludes that distribution of n-alkanes in the n-C/sub 15/ - nC/sub 22/ range with strong predominance of the even numbered homologs have been identified in coal, rocky coals and adjacent sediments of two seams formed in a paralic environment (Nograd Basin, lower Miocene). This is consistent with the previous findings in a recent estuarine system and a sound where direct bacterial inputs have been suggested. The preservation of this signature over geological time deserves particular interest from the geochemical standpoint for defining the development of bacterial sources in certain favourable, depositional environments. 17 references.

This year, Naturwissenschaften celebrates its 100th anniversary. Springer’s flagship multidisciplinary science journal was founded in 1913, and the first print issue of Naturwissenschaften (NAWI) was published on January 3 of that year (Autrum 1988). Since 2009, the sub-title The Science of Nature has been published alongside the journal title; however, the original title in German remains the official name of the journal, recognizing its origins and strong connection to European history of the twentieth century. NAWI covers all aspects of the natural sciences, focusing on articles in biology, chemistry, geology, and physics. Published monthly, the journal is dedicated to the fast publication of high-quality, peer-reviewed research. Reviews, Original Articles, Concepts and Synthesis, Short Communications, and Comments and Replies are published as onlinefirst articles before appearing in print. From 2013, the print of color is for free. The journal was a reflection of the physical and chemical sciences of its time in its first decades; it then gradually developed to include topics of interest to the broader community in the biological sciences. Today, publications contribute mainly to questions of general biological significance and come from the chemical, biological, geological, and physical sciences. The goal for our second century is to promote the exchange of ideas in all topics related to the biological sciences and beyond. Some changes to the structure of the journal including article types have been implemented in support of this strategy (Thatje 2012a). We look forward to publishing papers in fields especially relevant to the science and society of the Twenty-first century, including areas such as global change, genomics, biorobotics, and neurobiology. In order to support this development, a “Special Article Theme” section will be launched later this year. For the 100th anniversary, the Arnold Berliner Award (Thatje 2012b) will be established in recognition of its founder who guided the development of the journal over the exceptionally long period of 22 years. The award will be given annually for the best research article published in Naturwissenschaften during the previous calendar year, and it is my special honor to announce the first awardee later this year. Honoring the efforts of the journal’s founding editor, Dr. Arnold Berliner, on the occasion of his 70th birthday, Albert Einstein wrote, “His journal cannot be thought away from the life of our time.” (Einstein 1932). Eightyyears on, Naturwissenschaften remains one of the primary multidisciplinary science journals. I invite you to celebrate the journal and science, following our birthday activities throughout the year and into the journal’s second century of existence. Happy birthday, Naturwissenschaften!

The paper reviews current concepts of toxicological evaluation of new drugs and other chemicals. Instead of completing a predetermined check-list toxicologists now consider the potential adverse effects of the substances under actual conditions of use. They then design experimental models which have a high probability to predict the toxic effects. Moreover, the enhanced susceptibilities of special risk populations is more and more taken into consideration.

The direct conversion of solar energy to electrical energy (photovoltaic effect) by solar cells is receiving increasing attention on a world-wide scale. Photovoltaic energy conversion offers itself to a practical and meaningful implementation in regions without a conventional energy grid. This paper deals with the principles of silicon solar cells for terrestrial applications and new methods for the production of the necessary silicon.

G.A. Wagner and E. Pernicka Max-Planck-Institut ftir Kernphysik, D-6900 Heidelberg G. Gialoglou Institute of Geology and Mineral Exploration, Limenaria, Thasos, Greece M. Vavelidis Mineralogisch-Petrographisches Institut der Universit/it, D-6900 Heidelberg In a previous contribution [1] we have re- ported for the first time on the re-discovery of one of the ancient gold mines on Thasos mentioned by Herodotus [2]: a gallery (TG 80A) situated on the southern slope of the Klisidi ridge above Palaiochori near Kinyra. However, the existence of one sin- gle gallery only did not fully comply with Herodotus' text that "a whole mountain has been turned upside-down in the search for gold" [2]. Stimulated by this historical source we re-visited the Kinyra area during our 1980 campaign in order to check on the possibility of a more extended mining operation in antiquity. Just below the Phanos-Klisidi ridge in 520 m altitude we found a narrow, overgrown shaft entrance, which might be identical with one of the ancient shafts mentioned for this area about fifty years ago [3]. The sloped shaft of approximately 40 m length leads into a big collapsed cavern of about 40 m across and 8 to 10 m high. From this cav- ern several addits extend into various di- rections. The shape of the galleries, the piles of rock waste produced by hammer- and-sledge work, tool marks on the walls and remnants of charcoal leave no doubt that this gallery system (TG 80E) is part of an ancient mining activity. Also the dump of rock waste extending down-hill from the shaft entrance provides evidence for ancient working. The mine will be stud- ied in more detail jointly with the archae- ologists from the Ecole Franqaise d'Athdnes. The purpose of the present paper is to re- port on chemical and mineralogical inves- tigations of the collected ore samples and on mining aspects. The samples were taken from red argillaceous fillings within marble (din) fissures. From the appearance of the galleries it is obvious that these fillings were searched by the ancient miners. For chemical analysis the samples were ground to less than 200 lam grain size and homoge- nized. An aliquot of 10 g was leached cen- trifuged and the supernatant solution sepa- rated by decanting. Gold was determined by neutron activiation, and silver and cop- per by atomic absorption (Table l). Miner- alogically the samples consist of magnetite, limonite, hematite, manganese oxides, py- rite, and chalcopyrite. To a minor degree also quartz, epidote, hornblende, sphene, and zircon occur. Ore-microscopic studies revealed gold grains (