Investigating pathways of diagenetic organic matter sulfurization using compound-specific sulfur isotope analysis

We present the results of compound-specific sulfur isotope analyses performed on organic sulfur compounds (OSCs) isolated from sediments deposited in the euxinic Cariaco Basin, Venezuela. Individual OSCs (sulfurized highly branched isoprenoids and malabaricatriene) have sulfur isotope compositions of ca. −15‰, which is ³⁴S enriched by 5-15‰ relative to coeval bulk organic and inorganic sulfur pools. These observed differences in the sulfur isotope composition of bulk organic sulfur in the kerogen and bitumen pools and individual OSCs demonstrate that there are multiple pathways of organic sulfur formation operating simultaneously in marine sediments. Comparison of our measured compound-specific sulfur isotope data with values predicted using simple isotopic mass balance assumptions suggests that the sulfurization process likely involves multiple sources of inorganic sulfur. Further, the isotopic composition of these various precursor inorganic sulfur species and the specific pathway of sulfur incorporation into organic matter (OM) impart distinct isotopic compositions to the resulting organic sulfur compounds. These data represent the first compound-specific sulfur isotope measurements made in marine sediments, and demonstrate the utility of compound-specific sulfur isotope analysis in identification of inorganic sulfur sources for OM sulfurization and tracking pathways of sulfur incorporation, which will lead to a more complete understanding of diagenetic sulfurization of OM.     

Large-Scale Errors in ERS Altimeter Data

A method is described for mapping time-uncorrelated large-scale errors in satellite altimeter sea surface heights. Standard deviations of differences between pairs of successive measurements at track crossovers are computed, and the functional dependence of these deviations on absolute time difference is used to estimate the errors of individual measurements. This is first applied to all of ERS-1,2 altimeter data in the Pacific Ocean, yielding average errors of 3.2 cm in the deep ocean (>1 km) and 4.7 cm in the shallow seas (<1 km). The procedure is repeated for variable latitude bands, each with a full range of possible time differences, yielding a meridional profile of computed errors, ranging from 2.6 cm near the Antarctic continent (67–60S) and South Subtropical regions (25–5S) to 3.5 cm in the Antarctic Circumpolar Current (60–45S) and the Northern Hemisphere Subtropical and Subpolar Gyres. Finally, coarse-resolution maps of these errors are produced by subdividing the Pacific Ocean into latitude-longitude bins, each large enough to contain a sufficient number of samples for the functional fits. The larger errors are in Northwest and Subtropical Pacific, especially in South China Sea (4.3 to 4.5 cm) and off northern Australia (5.4 cm), while the smaller errors (2.5 to 3 cm) are in Northeast Pacific, central Tropical Pacific and near Antarctica in Southeast Pacific Ocean. These are lower bounds on altimeter errors, as they do not include contributions from time-correlated errors. We find that the computed error fields are not correlated with sea level standard deviations, thus disproving the notion that altimeter error variance can be scaled with the variance of sea surface height data.     

Contribution to Evaluation of Analytical Data On Reference Samples

For evaluating the analytical data on reference samples, the following approach is proposed: 1. Analytical methods used are critically reviewed. 2. Outliers are eliminated. 3. Normality of the results is tested. 4. If normality of the results can be accepted, arithmetic mean, its confidence interval and coefficient of the precision are computed. 5. If the results are not normally distributed, median and its statistical characteristics are given. 6. For sets of data with anomalous skewness, logarithmic and lambda transformations are useful approaches.     

Instability of interaction of interplanetary events with the earth's magnetosphere over long periods of time

Summary The position and size of the maximum of a model curve with one maximum during a half year were sought to provide the best linear relation between selected parameters, describing the geoactive event in the interplanetary medium, and the geomagnetic activity indices used and modulated additively by a model curve. The maxima for the separate half-years do not tend to cumulate and thus indicate that the sensitivity of the magnetosphere's reaction to an external stimulus may depend on parameters others than the angle of incidence at the magnetosphere.

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Резюме Искaлось месmоnоложенuе u знaченuе мaксuмумa мо?rt;ельноŭ крuвоŭ с о?rt;нuм мaкрuмумом в mеченuе nолу о?rt;a с целью nолучumь нauлучщее лuнеŭное оmнощенuе меж?rt;у выбрaннымu naрaмеmрaмu, оnuсывaющuмu еоaкmuвное собыmuе в межnлaнеmaрноŭ сре?rt;е, u меж?rt;у uн?rt;ексaмu еомa нumноŭ aкmuвносmu, uсnользовaннымu u мо?rt;улuровaннымu a?rt;?rt;umuвно nрu nомощu мо?rt;ельноŭ крuвоŭ. Мaксuмумы ?rt;ля оm?rt;ельных nолу о?rt;uŭ не nроявляюm mен?rt;енцuю к кумуляцuu u, maкuм обрaзом, свu?rt;еmельсmвуюm о mом, чmо чувсmрвumельносmь реaкцuu мa нumосферы к внещнему сmuмулу можеm зaвuсеmь оm ?rt;ру uх naрaмеmров, a не оm у лa na?rt;енuя нa мa нumосферу.

     

Industrial specialization and economic performance: A case of Czech microregions

An influential body of literature suggests that economic diversity rather than specialization fuels the economic performance of regions and nations. The authors argue that this hypothesis has no universal applicability and that a more differentiated view is needed. In particular, historical specificity of the local environment and structural characteristics of regional economies should be taken into account. They focus on the effects of industrial specialization on economic performance and the vulnerability of Central European post-communist regions, namely Czech microregions with less than 200,000 inhabitants. They examine whether the economic performance and vulnerability of these regions is fuelled rather by industrial specialization or diversity when controlling for other potential determinants of regional economic performance. Their findings show that the dependence of Czech regions on manufacturing correlates with higher economic performance but also with higher regional vulnerability. In addition, industrial specialization within manufacturing was found to be instrumental for the economic performance of regions with high dependence on manufacturing. With a decreasing share of employment in manufacturing, industrial diversity rather than specialization becomes more valuable for the economic performance of Czech regions.     

A Comparative Analysis of Favorability Mappings by Weights of Evidence,Probabilistic Neural Networks,Discriminant Analysis,and Logistic Regression

This study compares the performance of favorability mappings by weights of evidence (WOE), probabilistic neural networks (PNN), logistic regression (LR), and discriminant analysis (DA). Comparisons are made by an objective measure of performance that is based on statistical decision theory. The study further emphasizes out-of-sample inference, and quantifies the extent to which outcome is influenced by optimum variable discretization with classification and regression trees (CARTS).Favorability mapping methodologies are evaluated systematically across three case studies with contrasting scale and geologic information:

Gypsum: a review of its role in the deterioration of building materials

The deterioration of buildings and monuments by gypsum is the result of crystallization cycles of this salt. Although gypsum can dehydrate to a hemihydrate, the mineral bassanite, and to an anhydrate, the mineral anhydrite, this reaction occurs in nature on a geological time scale and therefore it is unlikely to occur when gypsum is found on and in building materials. The CaSO₄–H₂O system appears deceptively simple, however there are still discrepancies between the experimental and thermodynamically calculated data. The reason for the latter can be attributed to the slow crystallization kinetics of anhydrite. Apart from this, the large numbers of studies carried out on this system have focused on industrially important metastable phases, such as the hemihydrate and soluble anhydrite. The paper presents a review of the studies dealing with the phase equilibria of the CaSO₄–H₂O system as well as the influence of other salts on the solubility of gypsum. It tries to glean out the relevant information that will serve to explain the deterioration observed on building materials by the crystallization of gypsum and thus allows developing improved conservation methods.