Environmental selection and dispersal limitation are two of the primary processes structuring biotic communities in ecosystems, but little is known about these processes in shaping soil microbial ...communities during secondary forest succession. We examined the communities of ectomycorrhizal (EM) fungi in young, intermediate and old forests in a Chinese subtropical ecosystem, using 454 pyrosequencing. The EM fungal community consisted of 393 operational taxonomic units (OTUs), belonging to 21 EM fungal lineages, in which three EM fungal lineages and 11 EM fungal OTUs showed significantly biased occurrence among the young, intermediate and old forests. The EM fungal community was structured by environmental selection and dispersal limitation in old forest, but only by environmental selection in young, intermediate, and whole forests. Furthermore, the EM fungal community was affected by different factors in the different forest successional stages, and the importance of these factors in structuring EM fungal community dramatically decreased along the secondary forest succession series. This study suggests that different assembly mechanisms operate on the EM fungal community at different stages in secondary subtropical forest succession.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Production of ammonia is currently realized by the Haber-Bosch process, while electrochemical N
fixation under ambient conditions is recognized as a promising green substitution in the near future. A ...lack of efficient electrocatalysts remains the primary hurdle for the initiation of potential electrocatalytic synthesis of ammonia. For cheaper metals, such as copper, limited progress has been made to date. In this work, we boost the N
reduction reaction catalytic activity of Cu nanoparticles, which originally exhibited negligible N
reduction reaction activity, via a local electron depletion effect. The electron-deficient Cu nanoparticles are brought in a Schottky rectifying contact with a polyimide support which retards the hydrogen evolution reaction process in basic electrolytes and facilitates the electrochemical N
reduction reaction process under ambient aqueous conditions. This strategy of inducing electron deficiency provides new insight into the rational design of inexpensive N
reduction reaction catalysts with high selectivity and activity.
NOx− reduction acts a pivotal part in sustaining globally balanced nitrogen cycle and restoring ecological environment, ammonia (NH3) is an excellent energy carrier and the most valuable product ...among all the products of NOx− reduction reaction, the selectivity of which is far from satisfaction due to the intrinsic complexity of multiple‐electron NOx−‐to‐NH3 process. Here, we utilize the Schottky barrier‐induced surface electric field, by the construction of high density of electron‐deficient Ni nanoparticles inside nitrogen‐rich carbons, to facilitate the enrichment and fixation of all NOx− anions on the electrode surface, including NO3− and NO2−, and thus ensure the final selectivity to NH3. Both theoretical and experimental results demonstrate that NOx− anions were continuously captured by the electrode with largely enhanced surface electric field, providing excellent Faradaic efficiency of 99 % from both electrocatalytic NO3− and NO2− reduction. Remarkably, the NH3 yield rate could reach the maximum of 25.1 mg h−1 cm−2 in electrocatalytic NO2− reduction reaction, outperforming the maximum in the literature by a factor of 6.3 in neutral solution. With the universality of our electrocatalyst, all sorts of available electrolytes containing NOx− pollutants, including seawater or wastewater, could be directly used for ammonia production in potential through sustainable electrochemical technology.
The tunable surface electric field induced by Schottky barrier boosts the reduction of NOx− in water for ammonia production. The tunable amounts of Ni nanoparticles inside a nitrogen‐rich carbon support could gradually enhance the surface electric field for enriching and fixation of NOx− anions, achieving a high Faradaic efficiency of 99 % for ammonia production from both electrocatalytic NO3− and NO2− reduction.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Delamination of the lower lithosphere has occurred under different tectonic settings, thereby inducing strong lateral lithospheric strength heterogeneities. Here, we examine a recent case of ...plume‐induced lithosphere delamination associated with the Yellowstone plume. We propose that interaction between the Yellowstone plume and western North American lithosphere is what led to delamination of the lower lithosphere beneath the Columbia River Basalt (CRB) roughly ∼17 Myr ago. The excess melting that occurred when this “hole” was being filled by Yellowstone plume material was the primary trigger for the CRB excess melting event. The delaminated lower lithosphere currently lies to the northeast of the CRB; it can be clearly identified in recent seismic tomographic models. We suggest that both weak zones, for example, lithosphere‐crossing faults or suture zones, or vertical weaknesses associated with hotspot tracks, and strong zones (regions not underlain by weak mid‐lithosphere discontinuity material) can become the lateral boundaries of lithosphere delamination.
Plain Language Summary
In a few regions the continental lithosphere is not stable and its lower part has been thinned and destroyed. However, the controls on the geometry and boundary of this modification process remain largely unknown. Here, we use the continental lithosphere around the Yellowstone hotspot track as an example to show how hot material rising from the deep mantle can lead to the modification of overriding lithosphere. We propose that interaction between the hot Yellowstone plume and western North American lithosphere led to thinning of the lower lithosphere beneath the Columbia River Basalt (CRB) roughly ∼17 Myr ago. The excess melting that occurred when this “hole” was being filled by upwelling hot material was the primary trigger for the CRB melting event. The lower lithosphere that was delaminated currently lies to the northeast of the CRB; it can be clearly identified in recent seismic tomographic models. We suggest that both weak zones, either lithosphere‐crossing faults or suture zones, or vertical weaknesses associated with hotspot tracks, and strong zones which lack a weak internal layer in the middle of the lithosphere will form natural lateral boundaries to the delamination of the lower lithosphere.
Key Points
The lower lithosphere beneath the Columbia River Basalt has been delaminated and currently lies in mantle transition zone to the northeast
This location is consistent with absolute plate motions over the past 16 Myr
The geometry of “vertical” pre‐existing weak zones and a weak mid‐lithosphere layer controls the pattern of lithospheric delamination
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The wings of Lepidoptera contain a matrix of living cells whose function requires appropriate temperatures. However, given their small thermal capacity, wings can overheat rapidly in the sun. Here we ...analyze butterfly wings across a wide range of simulated environmental conditions, and find that regions containing living cells are maintained at cooler temperatures. Diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling that selectively reduces the temperature of structures such as wing veins and androconial organs. These tissues are supplied by circulatory, neural and tracheal systems throughout the adult lifetime, indicating that the insect wing is a dynamic, living structure. Behavioral assays show that butterflies use wings to sense visible and infrared radiation, responding with specialized behaviors to prevent overheating of their wings. Our work highlights the physiological importance of wing temperature and how it is exquisitely regulated by structural and behavioral adaptations.
Platinum (Pt) is the most effective bench‐marked catalyst for producing renewable and clean hydrogen energy by electrochemical water splitting. There is demand for high HER catalytic activity to ...achieve efficient utilization and minimize the loading of Pt in catalysts. In this work, we significantly boost the HER mass activity of Pt nanoparticles in Ptx/Co to 8.3 times higher than that of commercial Pt/C by using Co/NC heterojunctions as a heterogeneous version of electron donors. The highly coupled interfaces between Co/NC and Pt metal enrich the electron density of Pt nanoparticles to facilitate the adsorption of H+, the dissociation of Pt−H bonds and H2 release, giving the lowest HER overpotential of 6.9 mV vs. RHE at 10 mA cm−2 in acid among reported HER electrocatalysts. Given the easy scale‐up synthesis due to the stabilization of ultrafine Pt nanoparticles by Co/NC solid ligands, Ptx/Co can even be a promising substitute for commercial Pt/C for practical applications.
Co/NC heterojunctions are used as “solid ligands” to control the growth of as‐supported ultrafine Pt nanoparticles via donating electrons. Ultrafine Pt nanoparticles with enhanced electron density promote the proton capture from electrolyte to catalyst surface, the dissociation of Pt−H bonds and successive release of H2 molecules from the Pt surface.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Microbial diversity is generally far higher than plant diversity, but the relationship between microbial diversity and plant diversity remains enigmatic. To shed light on this problem, we examined ...the diversity of a key guild of root‐associated microbes, that is, ectomycorrhizal (EM) fungi along a plant diversity gradient in a Chinese subtropical forest. The results indicated that EM fungal diversity was positively correlated with host plant diversity. Furthermore, this relationship was best predicted by host genus‐level diversity, rather than species‐level diversity or family‐level diversity. The generality of this finding was extended beyond our study system through the analyses of 100 additional studies of EM fungal communities from tropical and temperate forests. Here as well, EM fungal lineage composition was significantly affected by EM plant diversity levels, and some EM fungal lineages were co‐associated with some host plant genera. These results suggest a general diversity maintenance mechanism for host‐specific microbes based on higher order host plant phylogenetic diversity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This paper presents one feature-based detector to find sea-surface floating small targets. In integration time of the order of seconds, target returns exhibit time-frequency (TF) characteristics ...different from sea clutter. The normalized smoothed pseudo-Wigner-Ville distribution (SPWVD) is proposed to enhance TF characteristics of target returns, which is computed from the SPWVDs of time series at the cell under test (CUT) and reference cells around the CUT. The differences between target returns and the TF pattern of sea clutter are congregated on the normalized SPWVD. From that the ridge integration (RI) is computed and significant TF points from each time slice form a binary image. The number of connected regions and the maximum size of connected regions in the binary image are extracted and are combined with the RI into a 3-D feature vector. Due to the unavailability of the feature vector samples of radar returns with target, a one-class classifier with a controllable false alarm rate is constructed from the feature vector samples of sea clutter by the fast convex hull learning algorithm. As a result, a new feature-based detector is designed. It is compared with the tri-feature-based detector using amplitude and Doppler features and the fractal-based detector using the Hurst exponent of amplitude time series on the recognized IPIX radar database for floating small target detection. The results show that a significant improvement in detection performance is attained.
A COOH-terminated nitrogen-doped carbon aerogel exhibited 100% selectivity to two-electron oxygen reduction, exceeding reported carbonaceous and noble metal catalysts. The optimal electrode with the ...synergistic effect of C–N/C–COOH resulted in a minimum ηO2/H2O2 and gave an evolution rate of 60 mg L−1 g−1 h−1 for H2O2 with satisfactory mechanical and electrochemical stability for practical applications.
Background:
Mild cognitive impairment (MCI) is an important stage between the normal cognitive decline of aging and dementia. The aim of this study was to compare and harmonize the recommendations ...for the diagnosis and treatment of MCI based on current clinical practice guidelines.
Methods:
We searched the PubMed, EMBASE, China National Knowledge Infrastructure, Wanfang Database, Chinese Science and Technology Periodical Database, and Chinese Biological Medicine Database from their inception date to April 24, 2021 to identify all published guidelines on MCI. The qualities of the eligible guidelines were appraised by two reviewers using the Appraisal of Guidelines for Research and Evaluation II instrument.
Results:
Thirteen guidance documents (four guidelines and nine consensus statements) with specific recommendations were included. Nine guidelines and consensus statements covered the screening and diagnosis of MCI. The evaluation of the documents showed that neuropsychological testing and biomarker assessments were the most common recommendations for the diagnosis of MCI. Nine of the 13 guidance documents covered the treatment and management of MCI. The recommendations for the treatment and management were classified into four categories, namely: intervention for risk reduction, pharmacologic interventions, non-pharmacologic interventions, and counseling. Regarding pharmacological interventions, three guidelines recommend no pharmacologic intervention. The use of cholinesterase inhibitors for MCI is contraindicated in three guidance documents, whereas one proposes that cholinesterase inhibitors and memantine should be deprescribed. EHb761
®
, Chinese herbal decoctions, and Chinese traditional patent medicine are recommended in two documents. A total of seven guidance documents recommend non-pharmacological interventions, including physical activity interventions, cognitive interventions, dietary and nutritional interventions, and acupuncture.
Conclusion:
An updated search for possible evidence on the diagnosis and treatment of MCI is needed. Potentially effective diagnoses and treatments, either conventional or complementary, and alternative therapies should be highly valued and addressed in correlation with the supporting evidence.
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