Tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from Minjera deposits, Istria, Croatia

The Minjera bauxites are the first analysed and mined bauxites in the world. They are a group of pyritised bauxites situated in northern Istria, developed during the subaerial exposure phase which marked a major part of the Late Cretaceous and Palaeocene in northern Istria. In this study, the morphology, petrography, mineralogy, geochemistry as well as stable sulphur isotopes of the D-1 and D-15 deposits from Minjera were studied, as well as the evolution of their bedrock and cover. This study found that those two deposits differ in morphology, mineralogy and geochemistry as a consequence of their different palaeotopographical positions, with the D-1 deposit located at a higher position at the time of its formation compared to D-15, which led to the higher degree of leaching and desilicification in the D-1 deposit. The pyritisation in the studied deposits was a multi-phase process, which began with the deposition of framboidal pyrite and micrometre-sized anhedral pyrite, over which colloform pyrite was precipitated. This indicates that the solutions were initially supersaturated with iron sulphide, saturation of which subsequently changed, as finally euhedral, dendritic and acicular pyrite were deposited, indicating undersaturated conditions. The final stage was marked by deposition of pyrite veins. This formational sequence of pyrites is also supported by stable sulphur isotopes, as the δ34S values exhibit a wide range from -40.86 to 2.32 ‰, where lower values indicate an open system with an unrestricted sulphate supply in which supersaturated conditions could have been achieved, while the higher values indicate a change towards a closed system with limited sulphate supply. The organic matter necessary for microbial sulphate reduction was derived from the marshy environment established atop of the bauxite. The initial flooding started in the Palaeocene, with the first part of the sequence being deposited under lacustrine conditions, which changed towards fully marine with the deposition of Foraminiferal limestones

Application of peritoneal dialysis in the therapy of acute exogenous poisonings

Iznesena su vlastita iskustva primjene peritonealne dijalize kao terapijske metode u 24 slučaja teških akutnih trovanja. Potpuni uspjeh je postignut u svih 10 bolesnika otrovanih lijekovima. Međutim, kada su u pitanju bili gljivini otrovi efekat ove terapijske metode je bio znatno slabiji. Od 14 teških trovanja gljivama 6 bolesnika je umrlo. Ovo se ne može pripisati slaboj efikasnosti peritonealne dijalize jer su nam bolesnici došli na odjeljenje sa jasnim znacima teškog oštećenja jetre, bubrega i drugih organa u organizmu.The authors describe own experience with the application of peritoneal dialysis as a therapeutic method in 24 cases of very serious exogenous poisoning by drugs and mushrooms. In 10 cases of drug poisoning a complete recovery took place, but in cases of mushroom poisoning this method was not very successful. Six patients (42.8) out of the 14 seriously poisoned by mushrooms died. This cannot be attributed to the ineffectiveness of peritoneal dialysis, because all patients were admitted to hospital with clear signs of serious damages of the liver, kidneys and other organs

Hysteresis, Avalanches, and Disorder Induced Critical Scaling: A Renormalization Group Approach

We study the zero temperature random field Ising model as a model for noise and avalanches in hysteretic systems. Tuning the amount of disorder in the system, we find an ordinary critical point with avalanches on all length scales. Using a mapping to the pure Ising model, we Borel sum the $6-\epsilon$ expansion to $O(\epsilon^5)$ for the correlation length exponent. We sketch a new method for directly calculating avalanche exponents, which we perform to $O(\epsilon)$. Numerical exponents in 3, 4, and 5 dimensions are in good agreement with the analytical predictions.Comment: 134 pages in REVTEX, plus 21 figures. The first two figures can be obtained from the references quoted in their respective figure captions, the remaining 19 figures are supplied separately in uuencoded forma

25 Years of Self-organized Criticality: Concepts and Controversies

Introduced by the late Per Bak and his colleagues, self-organized criticality (SOC) has been one of the most stimulating concepts to come out of statistical mechanics and condensed matter theory in the last few decades, and has played a significant role in the development of complexity science. SOC, and more generally fractals and power laws, have attracted much comment, ranging from the very positive to the polemical. The other papers (Aschwanden et al. in Space Sci. Rev., 2014, this issue; McAteer et al. in Space Sci. Rev., 2015, this issue; Sharma et al. in Space Sci. Rev. 2015, in preparation) in this special issue showcase the considerable body of observations in solar, magnetospheric and fusion plasma inspired by the SOC idea, and expose the fertile role the new paradigm has played in approaches to modeling and understanding multiscale plasma instabilities. This very broad impact, and the necessary process of adapting a scientific hypothesis to the conditions of a given physical system, has meant that SOC as studied in these fields has sometimes differed significantly from the definition originally given by its creators. In Bak’s own field of theoretical physics there are significant observational and theoretical open questions, even 25 years on (Pruessner 2012). One aim of the present review is to address the dichotomy between the great reception SOC has received in some areas, and its shortcomings, as they became manifest in the controversies it triggered. Our article tries to clear up what we think are misunderstandings of SOC in fields more remote from its origins in statistical mechanics, condensed matter and dynamical systems by revisiting Bak, Tang and Wiesenfeld’s original papers