Epistemological Perspectives on Simulation. An Introduction

LNAI Book Serie

First discovery of dolomite and magnesite in living coralline algae and its geobiological implications

Dolomite is a magnesium-rich carbonate mineral abundant in fossil carbonate reef platforms but surprisingly rare in modern sedimentary environments, a conundrum known as the "Dolomite Problem". Marine sedimentary dolomite has been interpreted to form by an unconfirmed, post-depositional diagenetic process, despite minimal experimental success at replicating this. Here we show that dolomite, accompanied by magnesite, forms within living crustose coralline alga, Hydrolithon onkodes, a prolific global tropical reef species. Chemical micro-analysis of the coralline skeleton reveals that not only are the cell walls calcitised, but that cell spaces are typically filled with magnesite, rimmed by dolomite, or both. Mineralogy was confirmed by X-ray Diffraction. Thus there are at least three mineral phases present (magnesium calcite, dolomite and magnesite) rather than one or two (magnesium calcite and brucite) as previously thought. Our results are consistent with dolomite occurrences in coralline algae rich environments in fossil reefs of the last 60 million years. We reveal that the standard method of removing organic material prior to Xray Diffraction analysis can result in a decrease in the most obvious dolomite and magnesite diffraction patterns and this may explain why the abundant protodolomite and magnesite discovered in this study has not previously been recognized. This discovery of dolomite in living coralline algae extends the range of palaeo-environments for which biologically initiated dolomite can be considered a possible source of primary dolomite.M. C. Nash, U. Troitzsch, B. N. Opdyke, J. M. Trafford, B. D. Russell and D. I. Klin

Biomineralization of dolomite and magnesite discovered in tropical coralline algae: a biological solution to the geological dolomite problem

Final revised paper can be found at Description (Link) belowDolomite is a magnesium-rich carbonate mineral abundant in fossil carbonate reef platforms but surprisingly rare in modern sedimentary environments, a conundrum known as the ''Dolomite Problem". Marine sedimentary dolomite has been interpreted to form by an unconfirmed, post-depositional diagenetic process, despite minimal experimental success at replicating this. Here we show that dolomite, accompanied by magnesite, forms within living crustose coralline alga, Hydrolithon onkodes, a prolific global tropical reef species. Chemical micro-analysis of the coralline skeleton reveals that not only are the cell walls calcitised, but that cell spaces are typically filled with magnesite, rimmed by dolomite, or both. Mineralogy was confirmed by X-ray diffraction. Thus there are at least three mineral phases present (magnesium calcite, dolomite and magnesite) rather than one or two (magnesium calcite and brucite) as previously thought. Our results are consistent with dolomite occurrences in coralline algae rich environments in fossil reefs. Instead of a theory of post-depositional dolomitisation, we present evidence revealing biomineralization that can account for the massive formations seen in the geologic record. Additionally, our findings imply that previously unrecognized dolomite and magnesite have formed throughout the Holocene. This discovery together with the scale of coralline algae dominance in past shallow carbonate environments raises the possibility that environmental factors driving this biological dolomitisation process have influenced the global marine magnesium/calcium cycle. Perhaps, most importantly, we reveal that what has been considered a geological process can be a biological process, having many implications for both disciplines.M. C. Nash, U. Troitzsch, B. N. Opdyke, J. M. Trafford, B. D. Russell and D. I. Klinehttp://hdl.handle.net/2440/6855

Impact of Systemic Inflammation and Autoimmune Diseases on apoA-I and HDL Plasma Levels and Functions

The cholesterol of high-density lipoproteins (HDLs) and its major proteic component, apoA-I, have been widely investigated as potential predictors of acute cardiovascular (CV) events. In particular, HDL cholesterol levels were shown to be inversely and independently associated with the risk of acute CV diseases in different patient populations, including autoimmune and chronic inflammatory disorders. Some relevant and direct anti-inflammatory activities of HDL have been also recently identified targeting both immune and vascular cell subsets. These studies recently highlighted the improvement of HDL function (instead of circulating levels) as a promising treatment strategy to reduce inflammation and associated CV risk in several diseases, such as systemic lupus erythematosus and rheumatoid arthritis. In these diseases, anti-inflammatory treatments targeting HDL function might improve both disease activity and CV risk. In this narrative review, we will focus on the pathophysiological relevance of HDL and apoA-I levels/functions in different acute and chronic inflammatory pathophysiological conditions

Thuringian State und University Library (ThULB) Jena - Branch Library of Medicine

The article presents the Thuringian State und University Library (ThULB) in Jena as an integrated single-tier library system and shows how its medicine section in particular was turned into a genuine multimedia library. Fully supplied with premium equipment, the medicine library is now host to more than 1000 scientists and about 2000 students of the university's medicine department.Der Artikel gibt einen Überblick zur Thüringer Universitäts- und Landesbibliothek (ThULB) Jena als integriertes einschichtiges Bibliothekssystem und stellt insbesondere die Entwicklung der Teilbibliothek Medizin zur multimedialen Bibliothek mit ihren differenzierten Aufgaben dar. Die moderne, technisch gut ausgestattete Bibliothek versorgt ca. 1000 Wissenschaftler und ca. 2000 Studierende der Medizinischen Fakultät

EPOS-Perspectives on Simulation. An Introduction

There is strong evidence that computer simulation is increasingly recognized as an important analytical tool in many social sciences disciplines and fields. During the last ten years, a number of new journals, which are devoted to this field, have been founded and others have increased their influence (i.e., JASSS, CMOT, Social Science Computer Review, Autonomous Agent and Multi-Agent Systems, Journal of Economic Dynamics and Control, Computational Economics, Computational Management Science). Special issues and extensive reviews of the literature have been published in influential and standard journals. At the same time, new international associations and societies were born, with an increasing number of members (i.e., ESSA in Europe, NAACSOS in North America, The Society for Computational Economics), many research centers and institutes have been successfully launched, many workshops, conferences and congresses are organized every year (with the first world congress on social simulation held in 2006 in Tokyo and the second one in Washington in 2008), and an open market of tools and simulation platforms (i.e., Swarm, Repast, Ascape, NetLogo), based on a vast community of developers and users, is steadily growing