Bioenergy,food security and poverty reduction: trade-offs and synergies along the water–energy–food security nexus

This article provides a review of trade-offs and synergies of bioenergy within the water–energy–food security nexus, with emphasis on developing countries. It explores the links of bioenergy with food security, poverty reduction, environmental sustainability, health, and gender equity. It concludes that applying the nexus perspective to analyses of bioenergy widens the scope for achieving multiple-win outcomes along the above aspects.     

Hysteresis‐Free 1D Network Mixed Halide‐Perovskite Semitransparent Solar Cells

The morphology of hybrid organic–inorganic perovskite films is known to strongly affect the performance of perovskite‐based solar cells. CH₃NH₃PbI_3‐xCl_x (MAPbI_3‐xCl_x) films have been previously fabricated with 100% surface coverage in glove boxes. In ambient air, fabrication generally relies on solvent engineering to obtain compact films. In contrast, this work explores the potential of altering the perovskites microstructure for solar cell engineering. This work starts with CH₃NH₃PbI_3‐xCl_x, films with grain morphology carefully controlled by varying the deposition speed during the spin‐coating process to fabricate efficient and partially transparent solar cells. Devices produced with a CH₃NH₃PbI_3‐xCl_x film and a compact thick top gold electrode reach a maximum efficiency of 10.2% but display a large photocurrent hysteresis. As it is demonstrated, the introduction of different concentrations of bromide in the precursor solution addresses the hysteresis issues and turns the film morphology into a partially transparent interconnected network of 1D microstructures. This approach leads to semitransparent solar cells with negligible hysteresis and efficiencies up to 7.2%, while allowing average transmission of 17% across the visible spectrum. This work demonstrates that the optimization of the perovskites composition can mitigate the hysteresis effects commonly attributed to the charge trapping within the perovskite film.     

Firms’ willingness to invest in a water fund to improve water-related ecosystem services in the Lake Naivasha basin,Kenya

A valuation scenario was designed using a contingent-valuation approach and presented to decision makers in business firms in Kenya’s Lake Naivasha basin to test how applicable a water fund might be as a potential financing mechanism for a payment for water-related ecosystem services scheme. The findings indicate that measuring a firm’s willingness to invest in ecosystem services could help determine whether a firm would invest and engage with other stakeholders to pool their investments in ecosystem services. Linking the institutional decision-making behaviour of a firm and its willingness to invest in a water fund is the novelty of this article.     

Rapid Parallel Synthesis of Bioactive Folded Cyclotides by Using a Tea‐Bag Approach

We report here the first rapid parallel production of bioactive folded cyclotides by using Fmoc‐based solid‐phase peptide synthesis in combination with a “tea‐bag” approach. Using this approach, we efficiently synthesized 15 analogues of the CXCR4 antagonist cyclotide MCo‐CVX‐5c. Cyclotides were synthesized in a single‐pot, cyclization/folding reaction in the presence of reduced glutathione. Natively folded cyclotides were quickly purified from the cyclization/folding crude mixture by activated thiol Sepharose‐based chromatography. The different folded cyclotide analogues were then tested for their ability to inhibit the CXCR4 receptor in a cell‐based assay. The results indicated that this approach can be used for the efficient chemical synthesis of libraries of cyclotides with improved biological properties that can be easily interfaced with solution or cell‐based assays for rapid screening.     

Phosphorus speciation in manure and manure-amended soils using XANES spectroscopy

Previous studies suggested an increase in the proportion of calcium phosphates (CaP) of the total phosphorus (P) pool in soils with a long-term poultry manure application history versus those with no or limited application histories. To understand and predict long-term P accumulation and release dynamics in these highly amended soils, it is important to understand what specific P species are being formed. We assessed forms of CaP formed in poultry manure and originally acidic soil in response to different lengths of mostly poultry manure applications using P K-edge X-ray absorption near-edge structure (XANES) spectroscopy. Phosphorus K-edge XANES spectra of poultry manure showed no evidences of crystalline P minerals but dominance of soluble CaP species and free and weakly bound phosphates (aqueous phosphate and phosphate adsorbed on soil minerals). Phosphate in an unamended neighboring forest soil (pH 4.3) was mainly associated with iron (Fe) compounds such as strengite and Fe-oxides. Soils with a short-term manure history contained both Fe-associated phosphates and soluble CaP species such as dibasic calcium phosphate (DCP) and amorphous calcium phosphate (ACP). Long-term manure application resulted in a dominance of CaP forms confirming our earlier results obtained with sequential extractions, and a transformation from soluble to more stable CaP species such as beta-tricalcium calcium phosphate (TCP). Even after long-term manure application (> 25 yr and total P in soil up to 13,307 mg kg(-1)), however, none of the manure-amended soils showed the presence of crystalline CaP. With a reduction or elimination of poultry manure application to naturally acidic soils, the pH of the soil is likely to decrease, thereby increasing the solubility of Ca-bonded inorganic P minerals. Maintaining a high pH is therefore an important strategy to minimize P leaching in these soils.     

From triadic closure to conference closure: the role of academic conferences in promoting scientific collaborations

An academic conference is not only a venue for publishing papers but also a nursery room for new scientific encounters. While previous research has investigated scientific collaboration mechanisms based on the triadic closure and focal closure, in this paper, we propose a new collaboration mechanism named conference closure. Conference closure means that scholars involved in a common conference may collaborate with each other in the future. We analyze the extent to which scholars will meet new collaborators from both the individual and community levels by using 22 conferences in the field of data mining extracted from DBLP digital library. Our results demonstrate the existence of conference closure and this phenomenon is more remarkable in conferences with high field rating and large scale attendees. Scholars involved in multiple conferences will encounter more collaborators from the conferences. Another interesting finding is that although most conference attendees are junior scholars with few publications, senior scholars with fruitful publications may gain more collaborations during the conference. Meanwhile, the conference closure still holds if we control the productivity homophily. Our study will shed light on evaluating the impact of a conference from the social function perspective based on the index of conference closure.     

Enhancing radiative cooling performance using metal-dielectric-metal metamaterials

Thermal energy management, especially cooling, is becoming increasingly important in today’s high energy consumption world. Passive cooling, which does not require additional energy consumption, could be an effective approach to thermal energy management. We analyzed spectral selective thermal emitters by investigating the performance of a type of passive cooling known as radiative cooling. Our results can be used to improve radiative cooling. As we can control the radiation characteristics of Metal-dielectric-metal (MDM) structures, we developed an MDM-based spectral selective emitter. We measured the spectral emissivity of the fabricated MDM structure in the direction of the zenith and at an incline. We also simulated structures of different sizes to determine the effect of varying the size of the structure on the emissivity. Finally, we calculated the radiative cooling performance of the selectively emissive surface. In these calculations, we considered temperature changes caused by atmospheric and surface radiation. The radiative cooling performance of our MDM-based spectral selective emitter was better than the cooling performance of a non-selective emitter. The surface temperature of the best MDM spectral selective emitter was 38 °C below the ambient temperature.