Near the boundary between ordered and disordered quantum phases, several experiments have demonstrated metallic behaviour that defies the Landau Fermi paradigm.sup.1-5. In moiré heterostructures, ...gate-tuneable insulating phases driven by electronic correlations have been recently discovered.sup.6-23. Here, we use transport measurements to characterize metal-insulator transitions (MITs) in twisted WSe.sub.2 near half filling of the first moiré subband. We find that the MIT as a function of both density and displacement field is continuous. At the metal-insulator boundary, the resistivity displays strange metal behaviour at low temperatures, with dissipation comparable to that at the Planckian limit. Further into the metallic phase, Fermi liquid behaviour is recovered at low temperature, and this evolves into a quantum critical fan at intermediate temperatures, before eventually reaching an anomalous saturated regime near room temperature. An analysis of the residual resistivity indicates the presence of strong quantum fluctuations in the insulating phase. These results establish twisted WSe.sub.2 as a new platform to study doping and bandwidth-controlled metal-insulator quantum phase transitions on the triangular lattice.
Mediterranean cork oak savannas, which are found only in southwestern Europe and northwestern Africa, are ecosystems of high socioeconomic and conservation value. Characterized by sparse tree cover ...and a diversity of understory vegetation -– ranging from shrub formations to grasslands -– that support high levels of biodiversity, these ecosystems require active management and use by humans to ensure their continued existence. The most important product of these savannas is cork, a non-timber forest product that is periodically harvested without requiring tree felling. Market devaluation of, and lower demand for, cork are causing a decline in management, or even abandonment, of southwestern Europe's cork oak savannas. Subsequent shrub encroachment into the savanna's grassland components reduces biodiversity and degrades the services provided by these ecosystems. In contrast, poverty-driven overuse is degrading cork oak savannas in northwestern Africa. "“Payment for ecosystem services"” schemes, such as Forest Stewardship Council (FSC) certification or Reducing Emissions from Deforestation and Degradation and enhancement of carbon stocks (REDD++) programs, could produce novel economic incentives to promote sustainable use and conservation of Mediterranean cork oak savanna ecosystems in both Europe and Africa.
Future changes in the mean, maximum, and minimum surface temperature over Europe are investigated according to CMIP6 future climate projections. All the temperature variables are projected to ...increase across Europe particularly in northern and southernmost latitudes, where according to SSP5-8.5 the warming can reach 2–3 (5–6) °C at the middle (end) of the current century. The warming is particularly strong in Northern (Mediterranean) areas in winter (summer) seasons. The occurrence of hot days (mean temperature > 30 °C) is projected to increase in all southern Europe by the end of the century (> 40–60 days/year), particularly in the southern parts of the Iberian Peninsula and Turkey. Increases in the occurrence of very hot days (maximum temperature > 40 °C) are projected in the central-southern areas of the Iberian Peninsula (30–40 days/year) and southern Turkey (> 50 days/year) in the end of the century. Tropical nights are expected to increase throughout the century in all Europe (except the northernmost latitudes), particularly at southern Europe for the 2081–2100 period (50–80 nights/year). Frost days (minimum temperature < 0 °C) are expected to occur less in all Europe towards the end of the century, with less than 50–70 days/year in central Europe and even less in Scandinavia and north-eastern Russia.
A method for digestion of soils with high inorganic matter content (ranging from 50 to 92%) by microwave-induced combustion (MIC) is proposed for the first time for further halogens (F, Cl, Br, and ...I) determination by ion chromatography (IC) and also by inductively coupled plasma mass spectrometry (ICP-MS). Microcrystalline cellulose (100–500 mg), used as a combustion aid, was mixed with sample and water or NH4OH solutions (10–100 mmol L–1) were investigated for analytes absorption. The use of cellulose (400 mg) was mandatory to volatilize the halogens from soils with high inorganic matter. It was possible to use diluted absorbing solutions (up to 100 mmol L–1 NH4OH) for halogens retention, providing limits of quantification in the range of 0.06 (I) to 60 (Cl) μg g–1. Accuracy was evaluated using certified reference materials (CRMs), spiked samples, and pyrohydrolysis method. Recoveries for halogens after spiked samples were in the range of 94 to 103% and the results after digestion of CRMs by MIC were in agreement better than 95% to certified values. Blanks were low, relative standard deviation was below 8% for all soils and no statistical difference was observed for results by pyrohydrolysis and MIC methods showing the feasibility of the proposed method for further halogens determination in soil samples.
Structure-based virtual screening (VS) is a widely used approach that employs the knowledge of the three-dimensional structure of the target of interest in the design of new lead compounds from ...large-scale molecular docking experiments. Through the prediction of the binding mode and affinity of a small molecule within the binding site of the target of interest, it is possible to understand important properties related to the binding process. Empirical scoring functions are widely used for pose and affinity prediction. Although pose prediction is performed with satisfactory accuracy, the correct prediction of binding affinity is still a challenging task and crucial for the success of structure-based VS experiments. There are several efforts in distinct fronts to develop even more sophisticated and accurate models for filtering and ranking large libraries of compounds. This paper will cover some recent successful applications and methodological advances, including strategies to explore the ligand entropy and solvent effects, training with sophisticated machine-learning techniques, and the use of quantum mechanics. Particular emphasis will be given to the discussion of critical aspects and further directions for the development of more accurate empirical scoring functions.
Mine tailings pose a huge hazard for environmental and human health, and the establishment of vegetation cover is crucial to reduce pollutant dispersion for the surroundings. However, their hostile ...physicochemical conditions hamper plant growth, compromising phytoremediation strategies. This study aims to investigate the role of organo-mineral amendments and plant growth-promoting rhizobacteria (PGPR) on the improvement of mine tailings properties and Lolium perenne L. (ryegrass) growth. Plants were grown in mine tailings mixed with an agricultural soil (1:1), 10% compost, and supplied with two different inorganic amendments – rock phosphate (6%) or lime (3%), and inoculated with the rhizobacterial strains Advenellakashmirensis BKM20 (B1) and Mesorhizobium tamadayense BKM04 (B2). The application of organo-mineral amendments ameliorated tailings characteristics, which fostered plant growth and further enhanced soil fertility and microbial activity. These findings were consistent with the increase of total organic carbon levels, with the higher numbers of heterotrophic and phosphate solubilizing bacteria, and higher dehydrogenase and urease activities, found in these substrates after plant establishment. Plant growth was further boosted by PGPR inoculation, most noticeable by co-inoculation of both strains. Moreover, inoculated plants showed increased activities for several antioxidant enzymes (catalase, peroxidase, polyphenoloxidase, and glutathione reductase) which indicate a reinforced antioxidant system.
The application of agricultural soil, compost and lime associated with the inoculation of a mixture of PGPR proved to enhance the establishment of vegetation cover, thus promoting the stabilization of Kettara mine tailings. Nonetheless, further studies are needed in order to confirm its effectiveness under field conditions.
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•Organo-mineral amendments play a key role in plant establishment in mine tailings.•Combined use of organo-mineral amendments and PGPR enhanced ryegrass growth.•Co-inoculation with metal resistant PGPR further improved plant growth.•Bacterial inoculation improved plant resistance to metals.•Bioinoculation stimulated ryegrass antioxidant defense system.
Abstract Objectives To investigate the effect of 2 standardized exercise programs, muscle strength exercises (SE) and aerobic exercises (AE), on the plasma levels of brain-derived neurotrophic factor ...(BDNF) and depressive symptoms in 451 elderly women. Design A randomized controlled trial. Setting Belo Horizonte/MG–Brazil. Participants Community-dwelling older women (N=451; age, 65–89y). Intervention The participants were divided into 2 groups: SE and AE. Both protocols lasted 10 weeks, and 30 sessions (1-h sessions) in total were performed 3 times a week under the direct supervision of physical therapists. Main Outcome Measures Plasma levels of BDNF (enzyme-linked immunosorbent assay) and depressive symptoms (Geriatric Depression Scale). Results There was a significant difference for BDNF plasma levels between the SE and AE groups ( P =.009). Post hoc analysis revealed a pre-post intervention difference in BDNF levels only for the SE group ( P =.008). A statistically significant difference was found for the pre- and postintervention Geriatric Depression Scale scores in both groups ( P =.001), showing that the effects of both exercise protocols were comparable regarding depressive symptoms ( P =.185). Conclusions The present findings have demonstrated the positive effect of muscle strengthening and aerobic intervention on depressive symptoms in community-dwelling elderly women. Interestingly, only SE significantly increased the plasma levels of BDNF in our sample. The positive effects of physical exercise on depressive symptoms in the elderly were not mediated by BDNF.
Sudden pulse-like events of rapidly increasing CO
2-efflux occur in soils under seasonally dry climates in response to rewetting after drought. These occurrences, termed “Birch effect”, can have a ...marked influence on the ecosystem carbon balance. Current hypotheses indicate that the “Birch” pulse is caused by rapidly increased respiration and mineralization rates in response to changing moisture conditions but the underlying mechanisms are still unclear. Here, we present data from an experimental field study using straight-forward stable isotope methodology to gather new insights into the processes induced by rewetting of dried soils and evaluate current hypotheses for the “Birch“-CO
2-pulse. Two irrigation experiments were conducted on bare soil, root-free soil and intact vegetation during May and August 2005 in a semi-arid Mediterranean holm oak forest in southern Portugal. We continuously monitored CO
2-fluxes along with their isotopic compositions before, during and after the irrigation. δ
13C signatures of the first CO
2-efflux burst, occurring immediately after rewetting, fit the hypothesis that the “Birch” pulse is caused by the rapid mineralization of either dead microbial biomass or osmoregulatory substances released by soil microorganisms in response to hypo-osmotic stress in order to avoid cell lyses. The response of soil CO
2-efflux to rewetting was smaller under mild (May) than under severe drought (August) and isotopic compositions indicated a larger contribution of anaplerotic carbon uptake with increasing soil desiccation. Both length and severity of drought periods probably play a key role for the microbial response to the rewetting of soils and thus for ecosystem carbon sequestration.
Patients with pancreatic cancer have a poor prognosis apart from the few suitable for surgery. Photodynamic therapy (PDT) produces localised tissue necrosis but previous studies using the ...photosensitiser meso-tetrahydroxyphenylchlorin (mTHPC) caused prolonged skin photosensitivity. This study assessed a shorter acting photosensitiser, verteporfin.
Fifteen inoperable patients with locally advanced cancers were sensitised with 0.4 mg kg(-1) verteporfin. After 60-90 min, laser light (690 nm) was delivered via single (13 patients) or multiple (2 patients) fibres positioned percutaneously under computed tomography (CT) guidance, the light dose escalating (initially 5 J, doubling after each three patients) until 12 mm of necrosis was achieved consistently.
In all, 12 mm lesions were seen consistently at 40 J, but with considerable variation in necrosis volume (mean volume 3.5 cm(3) at 40 J). Minor, self-limiting extrapancreatic effects were seen in multifibre patients. No adverse interactions were seen in patients given chemotherapy or radiotherapy before or after PDT. After PDT, one patient underwent an R0 Whipple's pancreaticoduodenectomy.
Verteporfin PDT-induced tumour necrosis in locally advanced pancreatic cancer is feasible and safe. It can be delivered with a much shorter drug light interval and with less photosensitivity than with older compounds.
Future changes in the mean, maximum and minimum temperature in the Iberian Peninsula were investigated using bias-corrected EURO-CORDEX climate projections. The results show that the future ...temperatures are projected to substantially increase in all the Iberian Peninsula, particularly towards the end of the century at the south-central region. Mean and maximum temperatures are projected to increase around 2 °C (4 °C) for the 2046–2065 (2081–2100) period, with much higher frequencies of days above 20 (mean temperature) and 30 °C (maximum temperature). However, much higher increases are projected in the south of Spain, Cantabrian and Pyrinees mountain ranges, while lower ones are projected for the Atlantic coastal areas. In the south-central part of the Iberian Peninsula, hot days (mean temperature > 30 °C) are projected to increase 20–35 days/year (40–80 days/year) for the period 2046–2065 (2081–2100), while very hot days (maximum temperature > 40 °C) are projected to increase 10–25 days/year (10–50 days/year) for the period 2046–2065 (2081–2100). These results show a clear tendency, associated with a high confidence, in a significant increase of the surface temperatures and in the frequency of high temperature episodes in the southern part of the Iberian Peninsula, which can have severe impacts on the population, environment and economy. The currently hottest areas located in south-central Iberian Peninsula are also the ones with the highest projected temperature increases, which will significantly exacerbate the temperature stress in these areas.
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