Long-term ecological monitoring has contributed substantially towards advancements in theoretical and applied ecology. However, the costs to maintain a long-term monitoring site are enormous. ...Lightweight unmanned aerial vehicles (UAVs or drones) have been rapidly emerging as a new tool for local-scale monitoring. To evaluate the value of drone applications in long-term ecological studies, we combined drone-derived canopy variables, detailed ground-based stem-mapping data and topographic and edaphic variables from a 20-ha forest dynamics plot in a species-rich subtropical forest. Specifically, we evaluated the relative importance of these variables in explaining local-scale variation in forest stand and species measures. We found that drone-derived canopy variables contributed substantially towards explaining local patterns of biodiversity and more specifically in supporting a gap dynamics hypothesis in structuring observed forest biodiversity. Stand basal area was positively related with canopy closure, indicating the importance of protecting old-growth forests as carbon sinks. The importance of topographic and edaphic variables was also demonstrated, supporting a niche differentiation hypothesis in structuring patterns in biodiversity. Species-level analyses illustrated that light-demanding species were more strongly correlated with canopy variables than shade-tolerant species. We provide convincing evidence that drones can add substantial value to long-term ecological monitoring by providing low cost, high resolution data. Drones should be included in the ecologist's toolbox to complement traditional field surveys.
•We used a lightweight drone to map in detail forest canopy structure across a 20-ha subtropical forest dynamics plot.•We examined the added benefit of incorporating drone-derived variables in explaining local variation in both stand and species measures.•Drone-derived canopy variables contributed substantially towards explaining spatial patterns in biodiversity.•Species with different light requirements responded to canopy variables supporting gap dynamics successional theories.•Lightweight drone technologies offer great potential for long-term ecological studies.
The water vapor and trace gas impurities play important roles on CO2 capture performance using porous materials. We investigated the effects of H2O, SO2, and O2 on CO2 capture in a series of ZIFs ...with same SOD topology but different functional groups, such as ZIF-8, ZIF-90, ZIF-Cl, ZIF-NO2, and SALEM-2 by grand canonical Monte Carlo simulations. The results show that H2O and SO2 show a cooperative effect on CO2 adsorption in ZIF-NO2 and ZIF-90 containing polar functional groups, which results in enhanced CO2/N2 selectivity in presence of H2O or SO2. Especially, the presence of H2O or SO2 can enhance the CO2 uptake amounts and the CO2/N2 selectivity in ZIF-NO2 at all H2O or SO2 concentration. On the other hand, the presence of H2O, SO2 has negligible effect on CO2 adsorption and CO2/N2 separation in ZIF-8, ZIF-Cl, and SALEM-2. The presence of O2 has no effect on CO2 capture in all of the materials investigated. Our results indicate that, by changing the functionalities of ZIF materials, H2O and SO2 may play a positive role during CO2 adsorption and separation process.
•Green finance has the direct and indirect effects on the reduction of carbon dioxide emissions.•Technological innovation plays the mediating role in the mechanism.•Green fiscal policy has a ...significant moderating effect in the mediation path.•The empirical results of green tax remind a possibility of “green paradox.”•The effects of green finance and technological innovation on carbon dioxide emissions increase when the environmental quality exceeds the threshold value.
Compared to advanced economies, China is facing challenges in reducing CO2 emissions due to its lower income-level and unbalanced energy structure. It is important to build a long-term mechanism for financing sustainable industries and reducing CO2 emissions. Green finance and green fiscal policy are essential instruments for financing the long-term mechanism of a green economy. They are tightly related with technological innovation, which contributes to the reduction of CO2 emissions. Clarifying the nexus among green finance, green fiscal policy, technological innovation, and carbon dioxide emissions (CO2) is paramount for new policy design and climate change mitigation. As a result, we collect panel data from 30 provinces and municipalities in mainland China (excluding Tibet) from 2007 to 2020 to investigate the effects of green finance on CO2 emissions using mediation and conditional process models to determine further the roles of technological innovation and green fiscal policy. The study results indicated that CO2 emissions can be suppressed directly by green finance and indirectly through technological innovation. Moreover, when green fiscal policy rises to a higher level, the indirect effect of green finance increases significantly. The green tax, a crucial element of green fiscal policy, presents the possibility of a “green paradox.” Therefore, we further test the effects of green finance and technological innovation in terms of environmental quality through threshold effect models. Green finance can better facilitate technological innovation and then inhibit CO2 emissions when environmental quality is high. Based on the empirical findings, developing green finance and green fiscal policies could be continued by expanding pilots, adjusting tax rates, and broadening taxation scope.
The high-quality development of green economy is an important way for the future development of China’s economy, but the academic research is relatively few. Based on the panel data of 30 provinces ...(cities and districts) in China from 2003 to 2019, using Moran index, Spatial Dobbin Model (SDM), intermediary effect and so forth, this paper constructs an evaluation index for the high-quality development of green economy. This paper tries to answer the impact of green credit, carbon emissions and the high-quality development of the green economy and some other important questions. Answering the above questions can effectively help government departments to better formulate policies to achieve long-term development goalsThe results are as follows: the improvement of the level of green credit is conducive to promoting the high-quality development of green economy, and the rise of high-quality development level of green economy in a certain region will obviously drive the high-quality development level of green economy in adjacent regions. Meanwhile, carbon dioxide emission plays an intermediary role between green credit and high-quality development of green economy. The impact of green credit on the high-quality development of green economy is more obvious in areas with high economic development level. Moreover, with the improvement of high-quality development of green economy, the promotion effect of green credit is increasing. This research fills the gap in this field at home and abroad and provides ideas and suggestions for the future development of China’s economy.
China has become the world’s largest energy consumer with its energy consumption growth accounts for three-quarters of the global growth. It is necessary to measure its energy efficiency reasonably. ...Previous studies mainly investigated energy use efficiency from the perspective of direct energy consumption without considering the energy consumption related to intermediate production, and did not eliminate the influence of random errors and environmental variables, resulting in deviations in energy efficiency measurement results. Combining a non-competitive input–output model and a three-stage data envelopment analysis, and based on the perspective of synergistic CO2 and SO2 emission reduction, this study constructs a new environmentally extended energy efficiency model to elucidate the true energy efficiency of China’s export trade. The results are as follows. (1) The implied energy efficiency of China’s export trade is generally on the rise under environmental constraints. Although its real efficiency in excluding external environmental factors has declined, its potential for improvement is still great. (2) Technological innovation and the expansion of export trade scale are conducive to the improvement of energy efficiency. Due to overcapacity, increasing industry capital investment will not greatly improve energy efficiency, but will increase the energy consumption and pollution emissions. (3) The average energy saving potential of China’s export trade is 8.91%, and the average emission reduction potential is 11.77%. (4) From 2002 to 2017, the average annual growth rate of implied energy efficiency in export trade was 8.9%, and technological progress was the main source of growth.
Abstract
The separation of xylene isomers (
para
-,
meta
-,
orth
-) remains a great challenge in the petrochemical industry due to their similar molecular structure and physical properties. Porous ...materials with sensitive nanospace and selective binding sites for discriminating the subtle structural difference of isomers are urgently needed. Here, we demonstrate the adaptively molecular discrimination of xylene isomers by employing a NbOF
5
2−
-pillared metal–organic framework (NbOFFIVE-bpy-Ni, also referred to as ZU-61) with rotational anionic sites. Single crystal X-ray diffraction studies indicate that ZU-61 with guest-responsive nanospace/sites can adapt the shape of specific isomers through geometric deformation and/or the rotation of fluorine atoms in anionic sites, thereby enabling ZU-61 to effectively differentiate xylene isomers through multiple C–H···F interactions. ZU-61 exhibited both high
meta
-xylene uptake capacity (3.4 mmol g
−1
) and
meta
-xylene/
para
-xylene separation selectivity (2.9, obtained from breakthrough curves), as well as a favorable separation sequence as confirmed by breakthrough experiments:
para
-xylene elute first with high-purity (≥99.9%), then
meta
-xylene, and
orth
-xylene. Such a remarkable performance of ZU-61 can be attributed to the type anionic binding sites together with its guest-response properties.
Extensive efforts have been made to improve the separation selectivity of hydrocarbon isomers with nearly distinguishable boiling points; however, how to balance the high regeneration energy ...consumption remains a daunting challenge. Here we describe the efficient separation of hexane isomers by constructing and exploiting the rotational freedom of organic linkers and inorganic SnF
anions within adaptive frameworks, and reveal the nature of flexible host-guest interactions to maximize the gas-framework interactions while achieving potential energy storage. This approach enables the discrimination of hexane isomers according to the degree of branching along with high capacity and record mono-/di-branched selectivity (6.97), di-branched isomers selectivity (22.16), and upgrades the gasoline to a maximum RON (Research Octane Number) of 105. Benefitting from the energy regulation of the flexible pore space, the material can be easily regenerated only through a simple vacuum treatment for 15 minutes at 25 °C with no temperature fluctuation, saving almost 45% energy compared to the commercialized zeolite 5 A. This approach could potentially revolutionize the whole scenario of alkane isomer separation processes.
Abstract
As a quantum material, Weyl semimetal has a series of electronic-band-structure features, including Weyl points with left and right chirality and corresponding Berry curvature, which have ...been observed in experiments. These band-structure features also lead to some unique nonlinear properties, especially high-order harmonic generation (HHG) due to the dynamic process of electrons under strong laser excitation, which has remained unexplored previously. Herein, we obtain effective HHG in type-II Weyl semimetal β-WP
2
crystals, where both odd and even orders are observed, with spectra extending into the vacuum ultraviolet region (190 nm, 10th order), even under fairly low femtosecond laser intensity. In-depth studies have interpreted that odd-order harmonics come from the Bloch electron oscillation, while even orders are attributed to Bloch oscillations under the “spike-like” Berry curvature at Weyl points. With crystallographic orientation-dependent HHG spectra, we further quantitatively retrieved the electronic band structure and Berry curvature of β-WP
2
. These findings may open the door for exploiting metallic/semimetallic states as solid platforms for deep ultraviolet radiation and offer an all-optical and pragmatic solution to characterize the complicated multiband electronic structure and Berry curvature of quantum topological materials.
This study aims to characterize the gut microbiota in depressed patients with bipolar disorder (BD) compared with healthy controls (HCs), to examine the effects of quetiapine treatment on the ...microbiota, and to explore the potential of microbiota as a biomarker for BD diagnosis and treatment outcome. Analysis of 16S‐ribosomal RNA gene sequences reveals that gut microbial composition and diversity are significantly different between BD patients and HCs. Phylum Bacteroidetes and Firmicutes are the predominant bacterial communities in BD patients and HCs, respectively. Lower levels of butyrate‐producing bacteria are observed in untreated patients. Microbial composition changes following quetiapine treatment in BD patients. Notably, 30 microbial markers are identified on a random forest model and achieve an area under the curve (AUC) of 0.81 between untreated patients and HCs. Ten microbial markers are identified with the AUC of 0.93 between responder and nonresponder patients. This study characterizes the gut microbiota in BD and is the first to evaluate microbial changes following quetiapine monotherapy. Gut microbiota‐based biomarkers may be helpful in BD diagnosis and predicting treatment outcome, which need further validations.
The gut microbiota in depressed patients with bipolar disorder is characterized, as well as its associations with queitapine monotherapy. Short‐term quetiapine treatment fails to draw the microbial ecosystem of bipolar disorder (BD) patients close to that of healthy individuals. Notably, microbial markers show powerful efficacy in distinguishing patients from healthy controls and predicting treatment outcome.
The ship exhaust sniffing unmanned aerial vehicle (UAV) system can be applied to monitor vessel emissions in emission control areas (ECAs) to improve the efficiency of maritime law enforcement and ...reduce ship pollution. To solve the problems of large size, heavy weight and high cost of ship exhaust sniffing sensors, in this paper, a unique diffused mini-sniffing sensor was designed, which provides a low-cost, lightweight, and highly adaptable solution for ship exhaust sniffing UAV. To verify the measurement accuracy of the system, a large number of on-site tests were performed based in the mouth of the Yangtze River, and some cases of violation of the fuel sulfur content (FSC) were verified and punished. Maritime law enforcement officers boarded the ship to take oil samples from eight suspected ships and sent them to the laboratory for testing. The results showed that the FSCs of the eight ships in chemical inspection were all greater than the regulatory limit 0.5% (m/m) of the International Maritime Organization (IMO). The system enables authorities to monitor emissions using rotary UAVs equipped with diffused mini-sniffing sensors to measure the FSC of navigating ships, which couple hardware and operational software with a dedicated lab service to produce highly reliable measurement results. The system offers an effective tool for screening vessel compliance.
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