Core-top calibration of δ18O and δ13C of G. ruber (white) and U. mediterranea along the southern Adriatic coast of Italy

We carried out an extensive survey of the oxygen and carbon isotope composition of the planktic species G. ruber (white) and of the benthic species U. mediterranea along the southern Italian coast of the Adriatic Sea and in the Gulf of Taranto. Comparison with seasonal satellite-based sea surface temperature maps and water column profiles as well as with several sets of water samples allows estimation of the effect of salinity and different nutrient supply on the δ18O and δ13C of foraminifera. The results indicate that G. ruber (white), while being highly affected by different salinity and nutrient distributions related to circulation patterns of major water masses, dominantly record summer temperature conditions. U. mediterranea reflect the recent environmental conditions, such as nutrient supply and bottom water temperature characteristics, along the southern Italian coast and clearly show the transition from a near-coastal eutrophic system to an offshore oligotrophic system

Опыт использования интерактивного элемента «лекция» в электронном учебном курсе «Основы САПР»

Many arctic landscapes are rich in lakes that store large quantities of organic carbon in their sediments. While there are indications of highly efficient carbon burial in high-latitude lakes, the magnitude and efficiency of carbon burial in arctic lake sediments, and thus their potential as carbon sinks, has not been studied systematically. We therefore investigated the burial efficiency of organic carbon (OC), defined as the ratio between OC burial and OC deposition onto the sediment, in seven contrasting lakes in western Greenland representing different arctic lake types. We found that the OC burial efficiency was generally low in spite of the differences between lake types (mean 22%, range 11–32%), and comparable to lakes in other climates with similar organic matter source and oxygen exposure time. Accordingly, post-depositional degradation of sediment organic matter was evident in the organic matter C:N ratio, δ13C and δ15N values during the initial ~50 years after deposition, and proceeds simultaneously with long-term changes in, e.g., productivity and climate. Pore water profiles of dissolved methane suggest that post-depositional degradation may continue for several centuries in these lakes, at very low rates. Our results demonstrate that the regulation of the sediment OC burial efficiency is no different in arctic lakes than in other lakes, implying that the efficiency of the carbon sink in lake sediments depends similarly on environmental conditions irrespective of latitude

A set of exactly solvable Ising models with half-odd-integer spin

We present a set of exactly solvable Ising models, with half-odd-integer spin-S on a square-type lattice including a quartic interaction term in the Hamiltonian. The particular properties of the mixed lattice, associated with mixed half-odd-integer spin-(S,1/2) and only nearest-neighbour interaction, allow us to map this system either onto a purely spin-1/2 lattice or onto a purely spin-S lattice. By imposing the condition that the mixed half-odd-integer spin-(S,1/2) lattice must have an exact solution, we found a set of exact solutions that satisfy the {\it free fermion} condition of the eight vertex model. The number of solutions for a general half-odd-integer spin-S is given by $S+1/2$. Therefore we conclude that this transformation is equivalent to a simple spin transformation which is independent of the coordination number

Generalized Transformation for Decorated Spin Models

The paper discusses the transformation of decorated Ising models into an effective \textit{undecorated} spin models, using the most general Hamiltonian for interacting Ising models including a long range and high order interactions. The inverse of a Vandermonde matrix with equidistant nodes $[-s,s]$ is used to obtain an analytical expression of the transformation. This kind of transformation is very useful to obtain the partition function of decorated systems. The method presented by Fisher is also extended, in order to obtain the correlation functions of the decorated Ising models transforming into an effective undecorated Ising models. We apply this transformation to a particular mixed spin-(1/2,1) and (1/2,2) square lattice with only nearest site interaction. This model could be transformed into an effective uniform spin-$S$ square lattice with nearest and next-nearest interaction, furthermore the effective Hamiltonian also include combinations of three-body and four-body interactions, particularly we considered spin 1 and 2.Comment: 16 pages, 4 figure

Soil Water Characteristics of European SoilTrEC Critical Zone Observatories

Most of soil functions depend directly or indirectly on soil water retention and transmission, which explains their importance for many environmental processes within Earth's Critical Zones. Soil hydraulic properties are essential in irrigation and drainage studies for closing water balance equation, for predicting leaching of nutrients, for water supply to plants, and for other agronomical and environmental applications. Soil hydraulic properties reflect the structure of the soil porous system comprising pores of different geometry and sizes. This investigation comprises a detailed analytical study of soil hydraulic properties and climate conditions at 18 methodologically selected sites in Damma Glacier, Slavkov Forest, Marchfeld, and Koiliaris Critical Zone Observatories of SoilTrEC project. The local moisture regimes were assessed on a long-term basis by the Newhall model. The experimental data for soil water content at different potentials were used for assessing water storage capacity, pore size distribution, parameters of fitted retention curve equation, curve slope at the inflection point, and water permeability characteristics of each soil horizon. The differences of soil water retention and transmission characteristics-as fundamental properties describing soil structure-were explained by the different stages of soil profile development, parent materials, organic matter content, and land use histories

Interactions between temperature and energy supply drive microbial communities in hydrothermal sediment

Temperature and bioavailable energy control the distribution of life on Earth, and interact with each other due to the dependency of biological energy requirements on temperature. Here we analyze how temperature-energy interactions structure sediment microbial communities in two hydrothermally active areas of Guaymas Basin. Sites from one area experience advective input of thermogenically produced electron donors by seepage from deeper layers, whereas sites from the other area are diffusion-dominated and electron donor-depleted. In both locations, Archaea dominate at temperatures >45 °C and Bacteria at temperatures <10 °C. Yet, at the phylum level and below, there are clear differences. Hot seep sites have high proportions of typical hydrothermal vent and hot spring taxa. By contrast, high-temperature sites without seepage harbor mainly novel taxa belonging to phyla that are widespread in cold subseafloor sediment. Our results suggest that in hydrothermal sediments temperature determines domain-level dominance, whereas temperature-energy interactions structure microbial communities at the phylum-level and below

An interlaboratory study of TEX86 and BIT analysis of sediments, extracts and standard mixtures.

Two commonly used proxies based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) are the TEX86 (TetraEther indeX of 86 carbon atoms) paleothermometer for sea surface temperature reconstructions and the BIT (Branched Isoprenoid Tetraether) index for reconstructing soil organic matter input to the ocean. An initial round-robin study of two sediment extracts, in which 15 laboratories participated, showed relatively consistent TEX86 values (reproducibility ±3-4°C when translated to temperature) but a large spread in BIT measurements (reproducibility ±0.41 on a scale of 0-1). Here we report results of a second round-robin study with 35 laboratories in which three sediments, one sediment extract, and two mixtures of pure, isolated GDGTs were analyzed. The results for TEX86 and BIT index showed improvement compared to the previous round-robin study. The reproducibility, indicating interlaboratory variation, of TEX86 values ranged from 1.3 to 3.0°C when translated to temperature. These results are similar to those of other temperature proxies used in paleoceanography. Comparison of the results obtained from one of the three sediments showed that TEX86 and BIT indices are not significantly affected by interlaboratory differences in sediment extraction techniques. BIT values of the sediments and extracts were at the extremes of the index with values close to 0 or 1, and showed good reproducibility (ranging from 0.013 to 0.042). However, the measured BIT values for the two GDGT mixtures, with known molar ratios of crenarchaeol and branched GDGTs, had intermediate BIT values and showed poor reproducibility and a large overestimation of the "true" (i.e., molar-based) BIT index. The latter is likely due to, among other factors, the higher mass spectrometric response of branched GDGTs compared to crenarchaeol, which also varies among mass spectrometers. Correction for this different mass spectrometric response showed a considerable improvement in the reproducibility of BIT index measurements among laboratories, as well as a substantially improved estimation of molar-based BIT values. This suggests that standard mixtures should be used in order to obtain consistent, and molar-based, BIT values

Non-AIDS defining cancers in the D:A:D Study-time trends and predictors of survival : a cohort study

BACKGROUND:Non-AIDS defining cancers (NADC) are an important cause of morbidity and mortality in HIV-positive individuals. Using data from a large international cohort of HIV-positive individuals, we described the incidence of NADC from 2004-2010, and described subsequent mortality and predictors of these.METHODS:Individuals were followed from 1st January 2004/enrolment in study, until the earliest of a new NADC, 1st February 2010, death or six months after the patient's last visit. Incidence rates were estimated for each year of follow-up, overall and stratified by gender, age and mode of HIV acquisition. Cumulative risk of mortality following NADC diagnosis was summarised using Kaplan-Meier methods, with follow-up for these analyses from the date of NADC diagnosis until the patient's death, 1st February 2010 or 6 months after the patient's last visit. Factors associated with mortality following NADC diagnosis were identified using multivariable Cox proportional hazards regression.RESULTS:Over 176,775 person-years (PY), 880 (2.1%) patients developed a new NADC (incidence: 4.98/1000PY [95% confidence interval 4.65, 5.31]). Over a third of these patients (327, 37.2%) had died by 1st February 2010. Time trends for lung cancer, anal cancer and Hodgkin's lymphoma were broadly consistent. Kaplan-Meier cumulative mortality estimates at 1, 3 and 5 years after NADC diagnosis were 28.2% [95% CI 25.1-31.2], 42.0% [38.2-45.8] and 47.3% [42.4-52.2], respectively. Significant predictors of poorer survival after diagnosis of NADC were lung cancer (compared to other cancer types), male gender, non-white ethnicity, and smoking status. Later year of diagnosis and higher CD4 count at NADC diagnosis were associated with improved survival. The incidence of NADC remained stable over the period 2004-2010 in this large observational cohort.CONCLUSIONS:The prognosis after diagnosis of NADC, in particular lung cancer and disseminated cancer, is poor but has improved somewhat over time. Modifiable risk factors, such as smoking and low CD4 counts, were associated with mortality following a diagnosis of NADC

Core-top calibration of δ18O and δ13C of G. ruber (white) and U. mediterranea along the southern Adriatic coast of Italy

We carried out an extensive survey of the oxygen and carbon isotope composition of the planktic species G. ruber (white) and of the benthic species U. mediterranea along the southern Italian coast of the Adriatic Sea and in the Gulf of Taranto. Comparison with seasonal satellite-based sea surface temperature maps and water column profiles as well as with several sets of water samples allows estimation of the effect of salinity and different nutrient supply on the δ18O and δ13C of foraminifera. The results indicate that G. ruber (white), while being highly affected by different salinity and nutrient distributions related to circulation patterns of major water masses, dominantly record summer temperature conditions. U. mediterranea reflect the recent environmental conditions, such as nutrient supply and bottom water temperature characteristics, along the southern Italian coast and clearly show the transition from a near-coastal eutrophic system to an offshore oligotrophic system