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•Molecular dynamics of tight oil movability was studied via computational modeling.•The effects of geological heterogeneity on tight oil movability were investigated.•The molecular ...mechanism of tight oil migration behaviors was clarified.•Molecular insight on tight oil accumulation was proposed.•The tight oil accumulation threshold was evaluated by MD simulations.
Understanding the movability mechanism of tight oil in nano-pore throat systems is vital for evaluating the oil accumulation and enhancing oil recovery. In this study, molecular dynamics simulations have been employed to generate insights into the tight oil movability in quartz, calcite, and two kaolinite nano-pore throats. Simulation results demonstrate that the migration behavior and migration resistance of tight oil are closely related with mineral types. Specifically, the migration resistance is in the order of Fkaolinite (001) > Fkaolinite (00−1) > Fcalcite > Fquartz. Herein, the highest resistance of hydrophilic kaolinite is contributed by its extremely strong Jamin effect, while the higher resistance of calcite and moderate lipophilic kaolinite than quartz can be ascribed as stronger oil-pore interactions. Combining the reservoir characteristics and molecular simulation results, it can be concluded that sandstone tight oil is the easiest to accumulate, hydrophilic clay lacks accumulation potential, while carbonate and moderate lipophilic clay are expected to become key areas of tight oil exploration and development in the future. Furthermore, the threshold pore size of tight oil accumulation is proposed based on the migration resistance and basin overpressure characteristics, which can provide theoretical support for tight oil exploration. Overall, this study highlights the effect of complex geological heterogeneity on tight oil movability, which could facilitate future studies on the evaluation of tight oil accumulations.
Sleep is thought to be restorative to brain energy homeostasis, but it is not clear how this is achieved. We show here that Drosophila glia exhibit a daily cycle of glial mitochondrial oxidation and ...lipid accumulation that is dependent on prior wake and requires the Drosophila APOE orthologs NLaz and GLaz, which mediate neuron-glia lipid transfer. In turn, a full night of sleep is required for glial lipid clearance, mitochondrial oxidative recovery and maximal neuronal mitophagy. Knockdown of neuronal NLaz causes oxidative stress to accumulate in neurons, and the neuronal mitochondrial integrity protein, Drp1, is required for daily glial lipid accumulation. These data suggest that neurons avoid accumulation of oxidative mitochondrial damage during wake by using mitophagy and passing damage to glia in the form of lipids. We propose that a mitochondrial lipid metabolic cycle between neurons and glia reflects a fundamental function of sleep relevant for brain energy homeostasis.
The Beaufort Gyre is a key circulation system of the Arctic Ocean and its main reservoir of freshwater. Freshwater storage and release affects Arctic sea ice cover, as well as North Atlantic and ...global climate. We describe a mechanism that is fundamental to the dynamics of the gyre, namely, the ice‐ocean stress governor. Wind blows over the ice, and the ice drags the ocean. But as the gyre spins up, currents catch the ice up and turn off the surface stress. This governor sets the basic properties of the gyre, such as its depth, freshwater content, and strength. Analytical and numerical modeling is employed to contrast the equilibration processes in an ice‐covered versus ice‐free gyre. We argue that as the Arctic warms, reduced sea ice extent and more mobile ice will result in a deeper and faster Beaufort Gyre, accumulating more freshwater that will be released by Ekman upwelling or baroclinic instability.
Plain Language Summary
The Beaufort Gyre, located north of Alaska and Canada, is a key circulation system of the Arctic Ocean. Changes in its depth and circulation influence the evolution of the Arctic sea ice cover, the North Atlantic circulation, and the global climate. The gyre is driven by persistent, ice‐mediated winds, accumulating surface freshwater toward the center, deepening the gyre, and spinning up its currents. We describe a mechanism, dubbed here the ice‐ocean governor, in which the interaction of surface currents with the ice regulates the depth of the Beaufort Gyre: The spinning up of the gyre reduces the relative speed between the ocean and the ice, and hence the freshwater accumulation. This competes with, and we argue is more important than, the release of freshwater by flow instability, which moves water from the center toward the periphery. In the current climate the depth and speed of the Beaufort Gyre are mainly set by the governor, but this may change in a warming world where reduced ice cover will render the ice‐ocean governor less effective. The resulting deeper, swifter gyre will likely exhibit more variability in its freshwater storage and flow speeds.
Key Points
Spin‐up of the Beaufort Gyre is regulated by a negative feedback between ice‐ocean stress and surface currents: an ice‐ocean stress governor
In the present Arctic system, the governor is likely a key process controlling the equilibration of the gyre
Continued sea ice loss will likely lead to reduced effectiveness of the governor and change the fundamental internal dynamics of the gyre
Gurgaon, India's “millennium city”, is today synonymous with India's embrace of global real estate capital and private sector‐led urban development. This paper asserts that Gurgaon's spectacular ...urbanisation has been fundamentally underpinned by an uneven process of land acquisition, exemption and agrarian transformation. Shifting away from dispossession‐centred analyses of contemporary urbanisation in India, this paper explores Gurgaon's “urban villages” to consider the uneven integration of agrarian classes into emerging urban real estate markets. Through an examination of differential experiences of land acquisition and agrarian social change among Gurgaon's landowning classes, the paper seeks to trace complex and nonlinear processes of agrarian transformation which make possible landscapes of global accumulation.
High temperature (HT) has an adverse effect on rice grain filling by inhibiting the accumulation of storage materials. However, the regulatory mechanism of this inhibition remains unknown. Here, we ...report that Opaque2 like transcription factor OsbZIP58 is a key factor regulating storage material accumulation under HT. The OsbZIP58 gene promotes expression of many seed storage protein genes and starch synthesis genes while inhibits expression of some starch hydrolyzing α‐amylase genes under HT. The loss of OsbZIP58 function leads to floury and shrunken endosperms and dramatically reduced storage materials in the seeds under HT. HT is found to affect alternative splicing of OsbZIP58, promoting the formation of the truncated OsbZIP58β protein form over the full‐length OsbZIP58α protein form. The OsbZIP58β form has a lower transcriptional activity than the OsbZIP58α form, especially under HT condition. Interestingly, rice varieties with less heat sensitivity have reduced alternative splicing of OsbZIP58. Therefore, OsbZIP58 is a crucial gene in regulating storage material accumulation under HT and lower alternative splicing of OsbZIP58 may contribute to heat tolerance during grain filling.
High temperature (HT) can harm rice grain quality by significantly reducing the storage materials accumulation. Here we found the alternative splicing of OsbZIP58 can be induced by HT and the lower activity of OsbZIP58β encoded by alternative spliced transcript might account for the decrease of storage materials accumulation and seed quality control in rice under HT.
Maximizing initial aboveground woody biomass (AGB) accumulation in order to obtain early payments for carbon stocking is essential for the financial viability of reforestation programs fostered by ...climate mitigation efforts. Intensive silviculture, i.e., silviculture traditionally used in commercial forestry to maximize productivity and gains, has recently been advocated as a promising approach to enhance AGB accumulation in restoration plantations. However, this approach may hamper natural forest regeneration and ecological succession due to high competition between colonizing plants and planted trees. We investigated the impacts of different silvicultural treatments applied to restoration plantations with 20 native tree species on AGB accumulation and spontaneous regeneration of native woody species in an experiment set up in the Atlantic Forest of Brazil. Intensive silviculture demonstrated a remarkable potential to enhance AGB accumulation in restoration plantations by increasing up to three times the AGB of tree stands (from ∼25 to 75 Mg/ha in the 12th year). Intensive fertilization/weed control enhanced AGB accumulation, while higher tree density and the proportion of pioneers did not have a significant effect on AGB over the time. In spite of higher costs (cost increase of 13–19%), the cost-effectiveness for AGB accumulation of intensive silviculture was comparable to that of traditional silviculture applied to restoration (US$50–100/Mg AGB for 3 × 2 m spacing). Contrary to our expectations, we did not find a trade-off between AGB accumulation by planted trees and the spontaneous regeneration of tree species, since intensive silviculture enhanced the regeneration of both planted (total of 12 species) and colonizing woody species (total of 30 species) in the plantation understory. Specifically, a strong association was found between AGB stocks and the abundance and richness of colonizing species, a vast majority of which (90% of species and 95% of individuals) were dispersed by animals. We report a case of positive correlation between AGB stocking and woody species regeneration in the restoration of the Atlantic Forest. Fostering the establishment and maintenance of restoration tree plantations can, in some cases, be a win-win strategy for climate mitigation and biodiversity conservation in human-modified tropical landscapes.
Device-independent cryptography goes beyond conventional quantum cryptography by providing security that holds independently of the quality of the underlying physical devices. Device-independent ...protocols are based on the quantum phenomena of non-locality and the violation of Bell inequalities. This high level of security could so far only be established under conditions which are not achievable experimentally. Here we present a property of entropy, termed "entropy accumulation", which asserts that the total amount of entropy of a large system is the sum of its parts. We use this property to prove the security of cryptographic protocols, including device-independent quantum key distribution, while achieving essentially optimal parameters. Recent experimental progress, which enabled loophole-free Bell tests, suggests that the achieved parameters are technologically accessible. Our work hence provides the theoretical groundwork for experimental demonstrations of device-independent cryptography.
Jasmonic acid (JA) has been mostly studied in responses to biotic stresses, such as herbivore attack and pathogenic infection. More recently, the involvement of JA in abiotic stresses including ...salinity was highlighted; yet, its role in salt stress remained unclear. In the current study, we compared the physiological and biochemical responses of wild-type (WT) tomato (Solanum lycopersicum) cv Castlemart and its JA-deficient mutant defenseless-1 (def-1) under salt stress to investigate the role of JA. Plant growth, photosynthetic pigment content, ion accumulation, oxidative stress-related parameters, proline accumulation and total phenolic compounds, in addition to both enzymatic and non-enzymatic antioxidant activities, were measured in both genotypes after 14 days of 100 mM NaCl treatment. Although we observed in both genotypes similar growth pattern and sodium, calcium and potassium levels in leaves under salt stress, def-1 plants exhibited a more pronounced decrease of nitrogen content in both leaves and roots and a slightly higher level of sodium in roots compared to WT plants. In addition, def-1 plants exposed to salt stress showed reactive oxygen species (ROS)-associated injury phenotypes. These oxidative stress symptoms in def-1 were associated with lower activity of both enzymatic antioxidants and non-enzymatic antioxidants. Furthermore, the levels of the non-enzymatic ROS scavengers proline and total phenolic compounds increased in both genotypes exposed to salt stress, with a higher amount of proline in the WT plants. Overall the results of this study suggest that endogenous JA mainly enhanced tomato salt tolerance by maintaining ROS homeostasis.
Rural land dispossession has become a dominant mechanism of capital accumulation in the Chinese economy. However, the Chinese economy continues to rely on a migrant labor system that enables ...enterprises to accumulate capital precisely by not dispossessing laborers, but instead enlisting rural communities in absorbing costs of workforce maintenance. These dual and contradictory mechanisms are particularly visible in China's urban construction sector, where enterprises require both low-cost labor and low-cost land for profitability. This contribution draws on long-term ethnographic research in Lan-ding Village, a labor-sending community undergoing land expropriations in Sichuan Province, to document a new system of class stratification resulting from these dual accumulation mechanisms.
Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases which lacks ideal treatment options. Kaempferol and kaempferide, two natural flavonol compounds isolated from ...Hippophae rhamnoides L., were reported to exhibit a strong regulatory effect on lipid metabolism, for which the mechanism is largely unknown. In the present study, we investigated the effects of kaempferol and kaempferide on oleic acid (OA)-treated HepG2 cells, a widely used in vitro model of NAFLD. The results indicated an increased accumulation of lipid droplets and triacylglycerol (TG) by OA, which was attenuated by kaempferol and kaempferide (5, 10 and 20 μM). Western blot analysis demonstrated that kaempferol and kaempferide reduced expression of lipogenesis-related proteins, including sterol regulatory element-binding protein 1 (SREBP1), fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD-1). Expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT enhancer binding proteins β (C/EBPβ), two adipogenic transcription factors, was also decreased by kaempferol and kaempferide treatment. In addition, western blot analysis also demonstrated that kaempferol and kaempferide reduced expression of heme oxygenase-1 (HO-1) and nuclear transcription factor-erythroid 2-related factor 2 (Nrf2). Molecular docking was performed to identify the direct molecular targets of kaempferol and kaempferide, and their binding to SCD-1, a critical regulator in lipid metabolism, was revealed. Taken together, our findings demonstrate that kaempferol and kaempferide could attenuate OA-induced lipid accumulation and oxidative stress in HepG2 cells, which might benefit the treatment of NAFLD.
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