Payments for environmental services (PES) programmes have been widely promoted over the last few decades in many developing countries. Improving the livelihoods of environmental services (ES) ...suppliers is not only seen as a side benefit but is often considered a prerequisite for the viability of PES. Yet, the ability to draw ‘overview lessons’ over the impacts of PES on livelihoods from literature review studies remains limited. To overcome these shortcomings, we undertake a meta-analysis of causal statistical studies on the effects of PES on the livelihoods of ES suppliers in the developing world. The set-up of our meta-analysis allows us to draw more conservative but more reliable and generalisable overview lessons. Our findings suggest that PES programmes are likely to have positive but modest livelihood impacts on ES suppliers. Further, several institutional characteristics of PES are found to be correlated with more favourable livelihood impacts, such as high payments, high degree of voluntary participation, low transaction costs and better access to alternative income sources. Lastly, our results highlight the importance of controlling for unobservable confounders when undertaking original evaluation studies on the impacts of PES. These factors should be incorporated in the design, implementation and evaluation of PES.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Background
Cell-cell interactions are important for information exchange between different cells, which are the fundamental basis of many biological processes. Recent advances in single-cell ...RNA sequencing (scRNA-seq) enable the characterization of cell-cell interactions using computational methods. However, it is hard to evaluate these methods since no ground truth is provided. Spatial transcriptomics (ST) data profiles the relative position of different cells. We propose that the spatial distance suggests the interaction tendency of different cell types, thus could be used for evaluating cell-cell interaction tools.
Results
We benchmark 16 cell-cell interaction methods by integrating scRNA-seq with ST data. We characterize cell-cell interactions into short-range and long-range interactions using spatial distance distributions between ligands and receptors. Based on this classification, we define the distance enrichment score and apply an evaluation workflow to 16 cell-cell interaction tools using 15 simulated and 5 real scRNA-seq and ST datasets. We also compare the consistency of the results from single tools with the commonly identified interactions. Our results suggest that the interactions predicted by different tools are highly dynamic, and the statistical-based methods show overall better performance than network-based methods and ST-based methods.
Conclusions
Our study presents a comprehensive evaluation of cell-cell interaction tools for scRNA-seq. CellChat, CellPhoneDB, NicheNet, and ICELLNET show overall better performance than other tools in terms of consistency with spatial tendency and software scalability. We recommend using results from at least two methods to ensure the accuracy of identified interactions. We have packaged the benchmark workflow with detailed documentation at GitHub (
https://github.com/wanglabtongji/CCI
).
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•A mechanical vibration assisted laser direct energy deposition process is designed to manufacture SS316L/IN718 FGM.•Cracking is eliminated by mechanical vibration through refining ...microstructure and restraining brittle precipitations.•The deterioration of hardness and tensile properties are significantly improved by mechanical vibration.•A crack-free and reasonable-performance SS316L/IN718 FGM is successfully achieved with the mechanical vibration assistance.
In this study, a mechanical vibration assisted laser direct energy deposition was used to fabricate a functionally graded material composed of stainless steel 316L and Inconel 718. The effect of mechanical vibration on the microstructure, defects and mechanical properties of the prepared functionally graded material was studied. The results indicate that in the sample without the assistance of mechanical vibration, plenty of brittle Laves phase and NbC carbides form and induce the cracking in the specific compositional gradient range from 60 % stainless steel 316L/40 % Inconel 718 to 40 % stainless steel 316L/60 % Inconel 718. The Vickers hardness obtains a minimal value near the compositional region of 50 % stainless steel 316L/50 % Inconel 718. The tensile properties are terrible with an ultimate tensile strength of 309.7 MPa and an elongation of 7.8 %. In the sample with the assistance of mechanical vibration, the synchronous mechanical vibration could effectively restrain the cracks formation in the compositional gradient region by suppressing the brittle phases precipitation, weakening the dislocation aggregation and refining the grain size, and resultantly achieve decent tensile properties with an ultimate tensile strength of 642.6 MPa and an elongation of 22.4 % and significantly improve the deterioration of hardness in the compositional gradient region.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this communication, we demonstrate that the electrospinning process with a side-by-side dual spinneret can be a simple approach for fabricating bicomponent TiO2/SnO2 nanofibers with controllable ...heterojunctions. Specifically, both of the TiO2 and SnO2 components in the nanofibers are fully exposed to the surface. This morphology fully utilized the photogenerated holes and electrons during the photocatalytic process, thus leading to a high photocatalytic activity. We believe that this versatile approach can be extended to fabricate other novel high-efficiency bicomponent photocatalysts.
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IJS, KILJ, NUK, PNG, UL, UM
A self-consistent three-dimensional (3D) mathematical model was developed to predict the crystal growth and microstructure formation in the laser powder deposition (LPD) of single-crystal (SX) ...superalloy. The effects of the governing processing parameters of LPD, i.e. laser power, scanning speed, powder feeding rate on the crystal growth and microstructure formation were studied systemically through the mathematical modeling and experimental approaches. Experiments with SX nickel-based superalloy Rene N5 were conducted to verify the computational results. The results indicate that the processing parameters have a profound influence on the molten pool shape and in turn the resulted epitaxial crystal growth patterns in the deposited bead. The height ratio (height of epitaxial columnar dendrite to total height of deposit) of the epitaxial columnar dendrite along the 001/〈100〉 crystallographic orientation increases up to 52% with the increase of the scanning speed, but decreases down to 42% with the increase of laser power. The simulation results and experimental results of the epitaxial height ratio agree reasonably well. With the optimized processing parameters, the laser deposited multi-layer SX sample with continuous growth columnar dendrite microstructure is demonstrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A novel direct printing approach for fabrication of in‐plane micro‐supercapacitors (MSCs) is demonstrated. Solution‐processed graphene/conductive‐polymer hybrid inks are utilized. The fabricated MSCs ...on paper substrates offer significant areal capacitance and excellent rate capability. An ultrathin MSC on a poly(ethylene terephthalate) (PET) substrate (2.5 μm thick) exhibits “ultraflexiblity,” making it suitable for next‐generation flexible microelectrochemical energy‐storage devices.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
It is still a challenge to photocatalytically cogenerate clean water and energy from dye wastewater owing to the relatively low photocatalytic efficiency of photocatalysts. In this study, ...novel-structured TiO2/CuO composite nanofibers were successfully fabricated via facile electrospinning. For the first time, the TiO2/CuO composite nanofibers demonstrated multifunctional ability for concurrent photocatalytic organic degradation and H2 generation from dye wastewater. The enhanced photocatalytic activity of TiO2/CuO composite nanofibers was ascribed to its excellent synergy of physicochemical properties: 1) mesoporosity and large specific surface area for efficient substrate adsorption, mass transfer and light harvesting; 2) red-shift of the absorbance spectra for enhanced light utilization; 3) long nanofibrous structure for efficient charge transfer and ease of recovery, 4) TiO2/CuO heterojunctions which enhance the separation of electrons and holes and 5) presence of CuO which serve as co-catalyst for the H2 production. The TiO2/CuO composite nanofibers also exhibited rapid settleability by gravity and uncompromised reusability. Thus, the as-synthesized TiO2/CuO composite nanofibers represent a promising candidate for highly efficient concurrent photocatalytic organic degradation and clean energy production from dye wastewater.
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•Novel-structured TiO2/CuO composite nanofibers were fabricated via electrospinning.•It exhibited high efficiency for photo-cogeneration of clean water and energy from wastewater.•Good mesoporosity; red-shift of UV–vis spectra; long nanofibrous structure.•TiO2/CuO heterojunctions easy for charge separation and CuO as hydrogen generation site.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Environmental pollution and food safety are two of the most important issues of our time. Soil and water pollution, in particular, have historically impacted on food safety which represents an ...important threat to human health. Nowhere has that situation been more complex and challenging than in China, where a combination of pollution and an increasing food safety risk have affected a large part of the population. Water scarcity, pesticide over-application, and chemical pollutants are considered to be the most important factors impacting on food safety in China. Inadequate quantity and quality of surface water resources in China have led to the long-term use of waste-water irrigation to fulfill the water requirements for agricultural production. In some regions this has caused serious agricultural land and food pollution, especially for heavy metals. It is important, therefore, that issues threatening food safety such as combined pesticide residues and heavy metal pollution are addressed to reduce risks to human health. The increasing negative effects on food safety from water and soil pollution have put more people at risk of carcinogenic diseases, potentially contributing to ‘cancer villages’ which appear to correlate strongly with the main food producing areas. Currently in China, food safety policies are not integrated with soil and water pollution management policies. Here, a comprehensive map of both soil and water pollution threats to food safety in China is presented and integrated policies addressing soil and water pollution for achieving food safety are suggested to provide a holistic approach.
•Water scarcity, pesticide over-application, and chemical pollutants are key factors impacting food safety.•Increasing negative effects on food safety from water and soil pollution pose health risk.•Cancer clusters caused by mixed pollution co-located with major food production areas.•Integrated policies addressing soil and water pollution for achieving food safety are suggested.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Multiple optical harmonic generation-the multiplication of photon energy as a result of nonlinear interaction between light and matter-is a key technology in modern electronics and optoelectronics, ...because it allows the conversion of optical or electronic signals into signals with much higher frequency, and the generation of frequency combs. Owing to the unique electronic band structure of graphene, which features massless Dirac fermions
, it has been repeatedly predicted that optical harmonic generation in graphene should be particularly efficient at the technologically important terahertz frequencies
. However, these predictions have yet to be confirmed experimentally under technologically relevant operation conditions. Here we report the generation of terahertz harmonics up to the seventh order in single-layer graphene at room temperature and under ambient conditions, driven by terahertz fields of only tens of kilovolts per centimetre, and with field conversion efficiencies in excess of 10
, 10
and 10
for the third, fifth and seventh terahertz harmonics, respectively. These conversion efficiencies are remarkably high, given that the electromagnetic interaction occurs in a single atomic layer. The key to such extremely efficient generation of terahertz high harmonics in graphene is the collective thermal response of its background Dirac electrons to the driving terahertz fields. The terahertz harmonics, generated via hot Dirac fermion dynamics, were observed directly in the time domain as electromagnetic field oscillations at these newly synthesized higher frequencies. The effective nonlinear optical coefficients of graphene for the third, fifth and seventh harmonics exceed the respective nonlinear coefficients of typical solids by 7-18 orders of magnitude
. Our results provide a direct pathway to highly efficient terahertz frequency synthesis using the present generation of graphene electronics, which operate at much lower fundamental frequencies of only a few hundreds of gigahertz.
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KISLJ, NUK, SBMB, UL, UM, UPUK
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