332 research outputs found
Problematic and objectively measured smartphone use in relation with personality (Big Five) and impulsivity
Antud töö eesmärgiks oli uurida inimeste objektiivselt mõõdetud ja problemaatilise nutitelefonikasutuse (PNK) seoseid isiksuseomaduste (Suure Viisiku) ja impulsiivsusega. Suure Viisiku omadusi (neurootilisus, ekstravertsus, avatus kogemusele, sotsiaalsus ja meelekindlus) mõõdeti XS-5 küsimustikuga ning impulsiivsust AMIS skaalaga, mis mõõdab eraldi nii adaptiivset (kiire otsustamise stiil, elamustejanu) kui maladaptiivset (mõtlematus, pidurdamatus) impulsiivsust. Problemaatilist nutitelefonikasutust mõõdeti E-SAPS18 testiga. Nutitelefonikasutust mõõdeti objektiivselt App Usage rakendusega, mis mõõdab inimese ööpäevast nutitelefoni kasutusaega ja -kordi (mitu korda telefoni ööpäevas lahti tehakse ja vaadatakse). Valimisse kuulus 114 inimest. Rakendus oli telefoni seadistatud 3 nädalat. Selgus, et PNK skaalal kõrgema skoori saanud uuritavate keskmine nutitelefoni kasutusaeg ning - sagedus olid suuremad, nad said kõrgemaid skoore ka neurootilisuse, ekstravertsuse, mõtlematuse ning pidurdamatuse skaalal. PNK skooriga oli negatiivselt seotud sotsiaalsuse skaala tulemus. Inimese nutitelefoni ööpäevasel keskmisel kasutusajal oli statistiliselt oluline positiivne seos PNK skooriga, keskmiste kasutuskordade, mõtlematuse ja pidurdamatusega. Inimese nutitelefoni ööpäevasel keskmistel kasutuskordadel oli statistiliselt oluline positiivne korrelatsioon PNK-ga, keskmise kasutusaja, ekstravertsuse, mõtlematuse ja pidurdamatusega
Making EU foreign policy via informal groupings: the case of the Minsk agreement and the Iran nuclear deal
Redox fluctuations, trace metal enrichment and phosphogenesis in the ~2.0 Ga Zaonega Formation
The ~2.0 Ga Zaonega Formation (ZF) holds one of the oldest phosphorites in the geologic record, reaching >15% P2O5. Understanding the depositional conditions that enabled sedimentary phosphorus enrichment in this unit will thus help us to interpret the significance of the temporal distribution of phosphorites in Earth’s early history. Here we use an array of major and trace element data to constrain the redox conditions in the water column and extent of basinal restriction during deposition of the ZF. We also present new selenium (Se) abundance and isotopic data to provide firmer constraints on fluctuations across high redox potentials, which might be critical for phosphogenesis. We find that Se isotope ratios shift over a range of ~3‰ in the ZF, with the earliest stratigraphically-resolved negative Se isotope excursion in the geologic record, implying at least temporarily suboxic waters in the basin. Furthermore, we find that redox-sensitive element (RSE) enrichments coincide with episodes of P enrichment, thereby implicating a common set of environmental controls on these processes. Together, our dataset implies deposition under a predominantly anoxic water column with periodic fluctuations to more oxidizing conditions because of connections to a large oxic reservoir containing Se oxyanions (and other RSE’s, as well as sulfate) in the open ocean. This is broadly consistent with the depositional setting of many modern and recent phosphorites, thereby tying these ancient deposits to a common depositional mechanism. In light of these data, we propose that the broader prevalence of phosphogenesis in the Paleoproterozoic Era was driven by growth of the seawater oxidant reservoir (namely sulfate), thus enabling diagenetic apatite precipitation in basins with high rates of export production, particularly by facilitating the activity of sulfide-oxidizing bacteria. This suggests that the muted authigenic P burial observed in marginal, marine siliciclastic sedimentary rocks during other intervals of the Precambrian was not merely a result of low dissolved P levels in the global deep ocean, but also was influenced by sulfate scarcity and strongly reducing bottom-water conditions
Recommended from our members
Stable and Clumped Isotope Characterization of Authigenic Carbonates in Methane Cold Seep Environments
Cold seep environments are characterized by methane-rich fluid migration and discharge at the seafloor. These environments are also intimately linked to microbial communities, which oxidize methane anaerobically, increase alkalinity and promote authigenic carbonate precipitation. We have analyzed a suite of methane-derived authigenic carbonate (MDAC) crusts from the North and Barents Sea using stable and clumped isotopes (δ¹³C, δ¹⁸O, δ⁴⁴Ca, and Δ₄₇) to characterize the sources of fluids as well as the environment of carbonate authigenesis. We additionally assess the potential of MDACs as a Δ₄₇-based paleotemperature archive.
The MDACs occur as three main textural-mineralogic types: micritic Mg-calcite cements, micritic aragonite cements and cavity filling aragonite cements. We find that micritic Mg-calcite cements have low δ¹³C_(VPDB) values (−30 to −47‰), high δ⁴⁴Ca_(SW) values (−0.4 to −0.8‰), and Δ₄₇-temperatures (0–6 °C) consistent with shallow sub-seafloor precipitation in isotopic equilibrium. Micritic aragonite cements and cavity filling aragonite cements both have a wider range in δ¹³C_(VPDB) values (−18 to −58‰), lower δ⁴⁴Ca_(SW) values (−0.8 to −1.6‰) and a larger range in Δ₄₇-based apparent temperatures (–2 – 25 °C) with samples displaying equilibrium and disequilibrium clumped isotope values.
The range in apparent temperatures as well as δ⁴⁴Ca_(SW) values seen in the aragonite MDACs suggest two kinetic processes: a kinetic isotope effect (KIE) due to the incomplete equilibration of carbon and oxygen isotopes among DIC species from the different sources of DIC (i.e., seawater, methane-sourced DIC and DIC residual to CO₂ degassing or diffusion) and a KIE due to a fast, irreversible precipitation affecting the cations, particularly Ca, bound to carbonate mineral. Our results improve the understanding of kinetic effects on clumped isotope temperatures in MDACs and demonstrate how the multi-isotopic approach combined with textural-mineralogic criteria can be used to identify MDACs for accurate paleotemperature reconstructions
Hydrothermal circulation and oil migration at the root of the heterogeneous micro-structure of carbonaceous material in the 2.0 Ga Zaonega Formation, Onega Basin, Russia
Organic-rich rocks of the 2.0 Ga Zaonega Formation, Karelia, Russia, have been studied extensively to gain understanding of the global carbon cycle and reconstruction of paleo-environments, directly after the Great Oxidation Event (GOE). This formation has a complex history of alteration, involving pervasive hydrothermal circulation, hydrocarbon generation/migration, and mineral authigenesis. Several previous studies have focused on the description of these secondary effects, and the identification of primary geochemical signals in the carbonaceous phases. Migration and infiltration of organic-rich fluids appear to have had only limited effect on the primary carbon isotope record (δ13Corg). However, the structural variability of carbonaceous material (CM) appears to have been strongly affected, with a range of reported structures including carbon onion-shaped nanostructures and mineral-templated graphite films. Here we present a systematic Raman spectroscopy-based study of the structural variability of CM in a drill core representing the middle and upper strata of the Zaonega Formation. The Raman spectra of CM show a systematic difference in structural order between the bulk carbonaceous matrix (Matrix-CM) and the CM occurring near mineral contacts (Contact-CM), indicating that mineral templating was an important process affecting structural order in the formation. The templating effect was observed on the surface of a wide range of minerals. The difference in structural order between Matrix-CM and Contact-CM can be traced throughout the ca. 400 m stratigraphy. The structural order varied with the degree of alteration and hydrothermal circulation, from highly ordered structures directly above a large gabbro intrusion at the bottom of the stratigraphy to less ordered structures higher up in the sequence. This trend directly correlates with the δ18O trend of secondary calcite, and can be attributed to the decreasing influence and temperature regime of hydrothermal circulation upward in the stratigraphy. The results presented here suggest that organic-rich hydrothermal fluids can locally strongly enhance graphitization of carbonaceous materials, and cause sample-scale heterogeneities in the structural order of organic materials. This has implications for the interpretation of carbonaceous materials in other ancient rocks experiencing circulation of organic-rich hydrothermal fluids.publishedVersio
Petrography and geochemistry of carbonate rocks of the Paleoproterozoic Zaonega Formation, Russia : Documentation of C-13-depleted non-primary calcite
The Norwegian Research Council grant 191530/V30 to V.A. Melezhik fully funded the work of AEC, VAM and AL. ATB was supported by NERC grant NE/G00398X/1 to AEF and ARP. We are grateful for sample preparation and analyses to all the personnel at NGU lab. We appreciate the work on carbon and oxygen isotope analyses by Julie Dougans and Chris Taylor. Bojan Otoničar organized and helped with the CL work at the Karst Research Institute at Postojna. Arrangement of TOC, IC, and TC analyses at University of Münster is acknowledged to Harald Strauss.Peer reviewedPostprin
Belief in alternative theories in relation with subjective well-being, political views and socioeconomic status
Antud töö eesmärgiks oli kaardistada alternatiivsetesse teooriatesse uskumise üldist levimust Eestis ning uurida selle võimalikke indiviiditasandi psühholoogilisi ja sotsiaalseid korrelaate. Vandenõu- ja pseudoteaduslikesse teooriatesse uskumist mõõdeti Alternatiivsetesse Teooriatesse Uskumise Skaalaga (ATUS). Subjektiivset heaolu (eluga rahulolu ja emotsionaalset kogemust) mõõdeti Eluga Rahulolu Skaalaga ning Positiivse ja Negatiivse Afektiivsuse Skaalaga (PANAS; negatiivne ja positiivne afektiivsus eraldi). Isiksuseseadumusi (neurootilisus, ekstravertsus, avatus kogemusele, sotsiaalsus, meelekindlus) mõõdeti Kümneväitelise Isiksuseküsimustikuga. Poliitilisi vaateid mõõdeti vasak-parem skaala ja 12 väitega, mis kirjeldasid erinevaid poliitilisi seisukohti. Sotsiaalmajanduslike ja demograafiliste näitajate puhul võeti arvesse inimese haridustaset, sissetulekut ja vanust. Valimisse kuulus 326 inimest (48.2% naised, keskmine vanus 32.2 aastat, SD = 11.3). Töö tulemustest selgus, et alternatiivsetesse teooriatesse uskumine on seotud madalama sotsiaalmajandusliku staatuse (haridustase, sissetulek), madalama subjektiivse heaoluga, kõrgema vanusega ning parempoolsete vaadetega. Käesolev töö annab kinnitust teooriale, et eksisteerib uskumuslik mõtteviis, mille järgi nii vandenõuteooriatesse uskumine kui ka pseudoteaduslikesse teooriatesse (sh üleloomulikesse jõududesse) uskumine on sarnased nähtused, mis on omavahel seotud
Increased barium levels in recent marine sediments from the Norwegian and Barents Seas suggest impact of hydrocarbon drilling and production
Barium (Ba) in recent marine sediments can originate from natural and anthropogenic sources including discharges from the oil and gas industry. In this study, we use data from the Norwegian and Barents Seas to assess whether Ba in recent marine sediments has increased due to these discharges. To account for Ba in detrital material, we normalise all samples with respect to aluminosilicate by calculating an enrichment factor. We use statistical modelling to control for parameters related to sedimentation. We present results that suggest increased Ba levels in recent sediments that coincide with the timing of hydrocarbon drilling and production. This is supported by geographical differences on a large scale that relate to proximity to hydrocarbon drilling and production. Among 243 sampling stations, we identify 73 locations exhibiting enrichment of Ba in the upper 6 of sediment. At these locations, Ba is 1.55 to 3.55 times higher than the levels that can be expected from the shale average when Ba in detrital matter is accounted for. Excess Ba is reported in sediment surface samples in areas important to fisheries like the Lofoten area and the western Barents Sea.publishedVersio
Hydrothermal regeneration of ammonium as a basin-scale driver of primary productivity
Funding: This study was financially supported by a NERC research grant (NE/V010824/1), and Estonian Science Agency project PRG447 to K.KHydrothermal vents are important targets in the search for life on other planets due to their potential to generate key catalytic surfaces and organic compounds for biogenesis. Less well studied, however, is the role of hydrothermal circulation in maintaining a biosphere beyond its origin. Here we explored this question with analyses of organic carbon, nitrogen abundances, and isotopic ratios from the Paleoproterozoic Zaonega Formation (2.0 Ga), NW Russia, which is composed of interbedded sedimentary and mafic igneous rocks. Previous studies have documented mobilization of hydrocarbons, likely associated with magmatic intrusions into unconsolidated sediments. The igneous bodies are extensively hydrothermally altered. Our data reveal strong nitrogen enrichments of up to 0.6 wt.% in these altered igneous rocks, suggesting that the hydrothermal fluids carried ammonium concentrations in the millimolar range, which is consistent with some modern hydrothermal vents. Further, large isotopic offsets of approximately 10 ‰ between organic-bound and silicate-bound nitrogen are most parsimoniously explained by partial biological uptake of ammonium from the vent fluid. Our results, therefore, show that hydrothermal activity in ancient marine basins can provide a locally high flux of recycled nitrogen. Hydrothermal nutrient recycling may thus be an important mechanism for maintaining a large biosphere on anoxic worlds.PostprintPeer reviewe
- …