Total Output Research Articles

Multimarket firms and product liability: uniform versus variable rules

Abstract When a multimarket firm’s product causes harm to consumers, should the firm bear uniform or variable liability across markets? We analyze a model in which the firm faces the same standard liability in two markets under uniform liability, while its liability rises above and falls below the standard level in markets 1 and 2, respectively, under variable liability. Allowing variation in product liability across markets has broad implications for the firm’s incentive to invest in product safety, total output, and output allocation across markets, as well as for the optimal choice of standard liability in the first place. We show that welfare is higher under variable liability if demand elasticity is lower and demand curvature is weakly higher in market 2 than in market 1, but welfare can be higher under uniform liability otherwise.

Examining the impact of climate change on cereal production in India: Empirical evidence from ARDL modelling approach

Agriculture sector is major sufferer of climate change both at a global level as well as at India level. Cereals account for about 92 % of India's total food grain output and climate change has a significant influence on the production of cereals. This study aimed to evaluate the long-term and short-term effects of climatic and non-climatic variables, specifically temperature, precipitation, cereal area, total cropped area, fertilizer consumption, and pesticide consumption, on cereal production in India. The study included annual time series data that covered the period from 1960 to 2018, covering a period of 58 years. Various econometric techniques were employed to examine these relationships. The validity of a long-term and short-term relationship among the relevant variables included in the study was validated by employing the Autoregressive Distributed Lag (ARDL) technique and the Johansen cointegration test. The ARDL model's estimation outcomes reveals that input factors such as cereal area became a key factor in rising cereal production, as evidenced by its positive coefficient. Similarly, fertilizer consumption and precipitation had positive effects on production in the long run whereas total cropped area and minimum temperature has little influence over the results of production both in short run as well as long run. Furthermore, the long-term findings were also supported using econometric tools like Canonical Cointegrating Regression (CCR) and Fully Modified Least Squares (FMOLS). These methods confirmed that variations in cereal production in India were significantly influenced by both climatic factors and agricultural inputs and factors. The study emphasizes the urgency for policymakers to prioritize proactive measures aimed at reducing the adverse impacts of climate change on cereal production in India. This necessitates a comprehensive strategy integrating sustainable practices, technological innovations, and robust policy frameworks to ensure resilient agricultural sectors and sustainable food production.

Analysis of the Economic Factors Influencing Rural Tourism Based on the Grey Relational Method: A Case Study of Zhejiang Province

The development of rural tourism is a key task for the revitalisation of rural areas and is of great significance for narrowing the gap between urban and rural areas and achieving shared prosperity. Zhejiang Province is one of the first provinces in China to develop rural tourism. Studying the factors influencing the economic impact of rural tourism in recent years is a reference for other provinces and cities to develop rural tourism and achieve rural revitalisation. This paper selects the total number of rural tourism visitors, the total number of farmhouses, the total number of rural tourism employees and the total number of travel agencies as variables to study their relationship with the total output value of rural tourism. Based on the data from 2013 to 2023, the grey correlation method is used to conduct an empirical analysis. The results show that the total number of rural tourists and the total number of travel agencies have a stronger impact on the development of rural tourism economy.

Data-driven interpretation, comparison and optimization of hydrogen production from supercritical water gasification of biomass and polymer waste: Applying ensemble and differential evolution in machine learning algorithms

Supercritical water gasification (SCWG) has been utilized for producing hydrogen from organic wastes, which is associated with sustainable development. Nevertheless, identifying the optimal SCWG conditions and appropriate catalysts for diverse waste materials to yield hydrogen-rich syngas is consistently a laborious and costly endeavor. The current research presents a comprehensive framework that combines machine learning models (Decision Tree, Ensembled Learning Tree, Support Vector Machine, and Gradient Boost Regression) with Differential Evolution Optimization (DEO) to predict and optimize hydrogen production from Supercritical Water Gasification (SCWG) using 24 different biomass characteristics and process parameters.The findings indicate that ELA-DEO emerges as the preferred method for forecasting hydrogen yield (R2test = 0.95, RMSETest = 0.091), demonstrating its effectiveness in handling intricate variable-target relationships. Conversely, Support Vector Machine (SVM) displayed weaker performance with an R2Test of 0.73 and RMSETest of 0.116. In the SHAP feature importance analysis, temperature, catalyst amount, catalyst type, hydrogen and oxygen were highlighted as important parameters affecting the process. In addition, by fine-tuning the machine learning hyperparameters, the DEO optimization method was used to maximize the production of H2. The optimized ELA-DEO model was used to identify the ideal features and conditions applicable to our experimental setup. Based on these findings, a recommended biomass table was finally formulated, which was validated by the ELA-DEO model. According to our laboratory results, Dunaliella salina produced 12 mmol of hydrogen with a 35% selectivity. Black liquor with 3% (wt) wood has the capacity to produce 17.21 mmol of hydrogen. Also, when crude glycerol was reacted with RuCl3, 18.7 mmol of hydrogen were generated. However, Dunaliella salina produced a 64% mole fraction of total gas output, which matched the maximum value predicted by our ELA-DEO models.

A benthic source of isotopically heavy Ni from continental margins and implications for global ocean Ni isotope mass balance

Nickel (Ni) is a bio-essential element for phytoplankton in the modern oceans, and yet, the global ocean mass balance of Ni has puzzled scientists for decades. Many estimates of total Ni output flux are larger than the total Ni input flux to the ocean. The measurement of Ni stable isotopes (δ60Ni) in earth materials may inform our understanding of ocean biogeochemistry and redox conditions in both the modern ocean and the geological past. An ocean Ni stable isotope imbalance has also concerned scientists, with a global ocean δ60Ni of +1.4 ‰ which is notably heavier than the major source of Ni to the oceans from rivers. Recent efforts to resolve Ni and δ60Ni imbalances have focused on the role which manganese (Mn) oxides play in marine Ni cycling, both in the water column and in marine sediments. Manganese oxide rich marine sediments can supply isotopically heavy dissolved Ni to porewater fluids and seawater, but the source of the isotopically heavy porewater Ni remains unclear. Here we present porewater trace metal concentrations and δ60Ni from two sites from the continental margin off southern California. Porewater Ni concentrations are up to roughly 100-fold higher than deep seawater concentrations (∼1 μM compared to 10 nM, respectively). Porewater δ60Ni is near 0 ‰ in the subsurface region where Ni concentrations are highest, suggesting dissolution of lithogenic material from sediments. Porewater δ60Ni increases dramatically towards the sediment-water interface with values of up to +2.66 ‰, which to our knowledge are the heaviest Ni isotope compositions ever reported for natural materials. Measurements of porewater and sediment Ni and Mn concentrations suggest that Ni is released to porewaters in the Mn-reducing zone, and then removed by newly precipitated Mn oxides as Mn and Ni move towards the oxygenated zone of sediments. A simple Rayleigh model suggests a Ni isotope fractionation of factor of -0.61 ‰ for Ni sorption onto Mn oxides, while a diffusion-reaction model suggests a Ni isotope fractionation of -1.80 to -0.96 ‰, always with preferential adsorption of lighter Ni isotopes. This flux of Ni toward the sediment-water interface, coupled with preferential removal of lighter Ni isotopes in marine sediments, provides evidence supporting an isotopically heavy benthic source of new Ni to the oceans, which we estimate has a magnitude of 0.65 × 108 to 1.66 × 108 moles/year. We find that a benthic flux such as measured here over just 0.27-2.70 % of the ocean seafloor could mix with the river δ60Ni of +0.8 ‰ to achieve the observed deep ocean δ60Ni of +1.4 ‰. This study reveals the similarities in how rivers and continental margin sediments supply heavy Ni isotopes to the ocean. In both continental rivers and margin sediments, terrigenous Ni is released with an δ60Ni near 0.1 ‰, but lighter isotopes are captured by precipitation onto oxides so that the dissolved flux to the ocean is isotopically heavier than the terrigenous material from which Ni was released, and in the case of margin sediments may be heavier than even bulk seawater δ60Ni. We thus recognize continental margin sediments with active Mn cycling as a ‘new’ source of isotopically heavy dissolved Ni to the ocean.

Large loss of reactive nitrogen and the associated environmental damages from tea production in China

Tea (Camellia sinensis L.), the most popular beverage worldwide and an important cash crop in China, plays a crucial role in the socio-economic landscape. Reactive nitrogen (Nr) loss from tea cultivation in China has become a major environmental problem due to the high input of N fertilizers. However, the scale of the Nr loss and its environmental impact on tea production in China remains unknown. Hence, we conducted a comprehensive meta-analysis of ammonia volatilization (NH3), nitrogen oxide (NOx), nitrous oxide (N2O) emissions, N leaching (total nitrogen, TN), and N runoff (TN) losses in tea plantations in China. The total Nr loss in Chinese tea plantations was 376 Gg yr−1 (149 kg N ha−1 yr−1) in 2014, with N leaching, NH3 volatilization, N2O emissions, NOx emissions, and N runoff losses accounting for 52.2 %, 33.2 %, 7.5 %, 5.4 %, and 1.7 %, respectively. The total Nr loss-related environmental damage cost of tea cultivation reached 9.53 billion CNY yr−1 in 2014, which was 7.7 % of the total tea production output value. The bulk of the environmental damage cost was attributed to NH3 volatilization (49.1 %), N2O emissions (24.9 %), and N leaching (19.2 %). Large Nr losses occurred during tea production in Sichuan, Hubei, Guizhou, Yunnan, Zhejiang, and Hunan provinces, accounting for 17.7 %, 17.0 %, 13.4 %, 10.7 %, 7.6 %, and 7.0 % of the total Nr losses in China, respectively. Our analysis showed that the adoption of integrated nutrient management reduced N fertilizer inputs to 300 kg N ha−1, lowered Nr loss from 376 Gg to 172 Gg yr−1, and reduced the environmental damage cost of N loss by 45.4 %. These findings, along with detailed data on the N balance of tea cultivation, provides critical information needed to develop effective region-specific N nutrient management practices and policies for sustainable and profitable tea crop production in China, and possibly in other similar geographies.

Low-Cost, Scalable Fabrication of Multi-Dimensional Perovskite Solar Cells and Modules Assisted by Mechanical Scribing.

The performance and scalability of perovskite solar cells (PSCs) based on 3D formamidinium lead triiodide (FAPbI3) absorber are often hindered by defects at the surface and grain boundaries of the perovskite. To address this, the study demonstrates the use of pyrrolidinium iodide for the in situ formation of an energetically aligned 1D pyrrolidinium lead triiodide (PyPbI3) capping layer over the 3D FAbI3 perovskite. The thermodynamically stable PyPbI3 perovskitoids, formed through cation exchange reactions, effectively reduce surface and grain boundary defects in the FAPbI3 perovskite. In addition to improved phase stability, the resulting 1D/3D perovskite film forms a cascade energy band alignment with the other functional layers in PSCs, enabling a barrier-free interfacial charge transport. With a maximum power conversion efficiency (PCE) of ≈23.1% and ≈20.7% at active areas of 0.09 and 1.05 cm2, respectively, the 1D/3D PSCs demonstrate excellent performance and scalability. Leveraging this improved scalability, the study has successfully developed a mechanically-scribed 1D/3D perovskite mini-module with an unprecedentedly high PCE of ≈20.6% and a total power output of ≈270mW at an active area of ≈13.0 cm2. The 1D/3D multi-dimensional perovskite film developed herein holds great promise for producing low-cost, high-performance perovskite photovoltaics at both the cell and module levels.

Optimal array layout design of wave energy converter via honey badger algorithm

Oceans cover approximately 71 % of the Earth's surface, wave energy presents a promising avenue for development. Hence, wave energy has garnered significant attention. Wave energy converters (WECs) are crucial technologies that transform wave energy into electrical power. The power output of wave farms largely depends on the complex hydrodynamic interactions among WECs, which are influenced by buoy positions and wave environment. Therefore, optimizing the buoy positions is a key strategy for enhancing the overall power output of WEC arrays. This paper adopts a novel meta-heuristic algorithm (MhA) named honey badger algorithm (HBA), designed to fully explore and exploit the constructive interactions among three-tether fully submerged WECs. To validate the effectiveness of HBA in optimizing WEC layouts, four different wave farm configurations with 2, 4, 10, and 20 buoys are analyzed. A comprehensive comparison is conducted using five typical MhAs against HBA. Experimental results demonstrate that HBA achieves the highest total power output with remarkable stability compared to alternative methods. Specifically, the q-factor values for the four wave farms are improved to 1.039, 1.027, 1.056, and 0.969, respectively. Additionally, the total power output of the 10-buoy and 20-buoy wave farms can be increased by up to 7.19 % and 4.4 %, respectively.

Carbon emission drivers of China's power sector and its transformation for global decarbonization contribution

To explore the contribution of China's power sector transformation to global CO2 emission reduction and the potential for this sector to achieve peak carbon, we used a hybrid input–output model to explore the direct CO2 emissions of six power sectors classified by generation methods and their impact on CO2 emission by the non-power sector based on the total power sector output (electricity generation). We then used structural decomposition analysis to explore the drivers. From 2012 to 2021, the total indirect CO2 emissions of China's power sector grew from 138.59 Mt to 158.79 Mt (the share in the carbon footprint increased from 3.7% to 3.9%), an increase of 14.6%. Over the period from 2012 to 2021, the power structure effect consistently reduced direct and indirect CO2 emissions. Policy scenario simulations showed that 12 scenarios for 2035 are expected to achieve peak carbon in China's power sector. The transition of China's power sector to cleaner energy will contribute greatly to global CO2 reduction in all sectors. In scenarios APS-DER-LD and APS-DER-HD, where the power structure effect was strongest, China and other countries will simultaneously experience large decreases in carbon emission, with decreases of 43.5 and 36.6%, respectively.

Noncontact magnetically coupled piezo-electromagnetic rotary energy harvester

Aiming at the problems of high environmental vibration frequency, low output power and short life of the energy harvesters, a noncontact magnetically coupled piezo-electromagnetic rotary energy harvester is proposed in this paper. It consists of a base, a top cover, a rotating body, a cantilever beam, a permanent magnet, a coil, a hollow tube and a clamp. The novel hybrid harvester can produce both piezoelectric and electromagnetic energy at the same time, and in addition, it can efficiently generate electricity at low ambient vibration. Moreover, the piezoelectric material is protected from direct collision by noncontact magnetic coupling excitation. In order to conduct a comprehensive study on the performance of the piezoelectric-electromagnetic rotary energy harvester, we set up a rotating test platform to carry out systematic test verification, and to determine the distance between the permanent magnet and the rotating body and the number of permanent magnets on the rotating body. The test results show that when four permanent magnets are uniformly pasted on the rotating body and the rotating speed is 775 r/min, the piezoelectric and electromagnetic output power are 3.4 mW and 2.69 mW, respectively, and the total hybrid output power is 6.09 mW.

Intercalation of V2O5 and Polypyrrole into a Graphene Oxide Layer: A Hybrid Multifunctional Photothermal Structure for Efficient Solar Evaporation, Water Purification, Disinfection, and Power Production.

Development of a hybrid multifunctional photothermal structure with multifunctional capabilities is deliberated as an effective approach for harvesting abundant solar energy for sustainable environmental applications. Achieving enhanced solar to thermal conversion efficiency utilizing a suitably designed, environmentally compatible thermal management structure however remains a significant challenge. Herein, we report the intercalation of V2O5 and polypyrrole into a graphene oxide layer to design a hybrid photothermal assembly (PPy-V2O5-GO) and its multifunctional proficiencies. The hybrid photothermal structure demonstrated synergistic photothermal conversion, buoyant porous structure sustaining water transmission, and efficient steam release. V2O5 and polypyrrole-intercalated optimized graphene oxide structure attained an evaporation rate of 1.9 kg m-2 h-1 with a conversion efficiency of 92% under 1 sun solar radiation. At maximum, the assembly's surface temperature hit 64 ± 2 °C, suggesting its suitability as a solar water purifier. Outdoor experiments suggest the evaporator assembly's capability to accumulate a total output of 15 kg m-2 over a single day. Cell viability investigations revealed strong antimicrobial properties of PPy-V2O5-GO against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria, eliminating nearly all under 1 sun, making it a potential candidate for photothermal therapy. Furthermore, when combined with a commercial thermoelectric module, the framework displayed exceptional photothermal conversion efficiency, hinting at its potential for electrical power generation. The integration of PPy-V2O5-GO with a Bi2Te3-based thermoelectric module significantly boosted the thermoelectric generator's performance, offering an enhanced power output of 2.8 mW and a high power density of 1.24 mW/cm2, making them suitable for off-grid or remote-area application. Overall, the PPy-V2O5-GO photothermal assembly's stability, lack of leaching, effectiveness in producing pure water from seawater, antimicrobial efficacies, and recyclability make it an excellent choice for sustainable water treatment and power generation.

Conformable fractional accumulation in triangular fuzzy sequences grey nonlinear model for tertiary industry gross output forecast

The prediction of the tertiary industry's output value is essential for enhancing the market economic system and providing guidance for the government in formulating relevant economic policies. The tertiary industry encompasses various sectors such as finance and transportation, and its total output value exhibits uncertain and nonlinear trends. Triangular fuzzy number sequences contain more comprehensive information than exact number sequences. Therefore, a nonlinear grey Bernoulli model with conformable fractional accumulation for triangular fuzzy sequences is proposed. Firstly, the conformable fractional accumulation generating operation is utilized to mitigate the volatility tendency of the original sequences. Additionally, a time power function term is introduced to capture the power exponential trend. Furthermore, an improved whale optimization algorithm incorporating opposition-based learning strategy and adaptive control parameters is employed to optimize the model parameters, which has been verified through algorithm comparison experiments. Three existing grey models are used as competing models to validate the prediction accuracy of our proposed model. Finally, we utilize this proposed model to predict the tertiary industry's output values in both Yangtze and Pearl River Deltas for 2024–2026.

Orthogonally polarized dual-wavelength Pr:LiYF4 lasers in 1.3 μm region

We report a continuous-wave (CW) orthogonally polarized dual-wavelength Pr:LiYF4 laser in 1.3 μm region pumped by a Yb-doped fiber laser. The gain and loss of the wavelengths in the orthogonally polarized directions were balanced by an inclined etalon inserted into the cavity. At an absorbed pump power of 9.2 W, a dual-wavelength laser operating at 1310 nm in π-polarization and 1326 nm in σ-polarization with 2.26 W of total output power was achieved. Moreover, by continuing to adjust the tilt angle of the etalon, the three other pairs of dual-wavelengths (1289 and 1306 nm, 1289 and 1306 nm, and 1306 and 1310 nm) were also obtained. The output power ratio of each pair of dual wavelengths was nearly 1:1. To the best of our knowledge, this is the first work realizing the Pr:LiYF4 laser operating in 1.3 μm region.

Efficacy of cardiopulmonary bypass method with blood delivery via femoral artery cannulation for paediatric aortic arch repair

IntroductionThe efficacy of cardiopulmonary bypass (CPB) management with blood delivery via femoral artery cannulation for paediatric aortic arch repair has yet to be reported. This study aimed to verify the hypothesis that this CPB method would reduce lactate elevation compared to CPB management using circulatory arrest of the lower body under deep hypothermia.MethodsThis study included patients who underwent paediatric aortic arch repairs between March 2012 and March 2018 at the German Paediatric Heart Centre, Sankt Augustin. Patients who were repumped intraoperatively were excluded. Group A (lower body circulatory arrest), Group F (retrograde aortic perfusion via femoral artery cannulation), and Group D (antegrade descending aortic perfusion) included 41, 18, and 15 patients, respectively. The CPB records were retrospectively reviewed for the minimum body temperature during CPB (℃), lactate levels before CPB (mmol/L), CPB duration (min), aortic clamp time duration (min), total urine output (mL) and changes in lactate levels during CPB (mmol/L).ResultsThe minimum body temperatures during CPB were 16.79 ± 1.48℃, 23.73 ± 4.67℃, and 30.59 ± 2.35 ℃ in Groups A, F, and D, respectively. The increases in lactate levels during CPB in Group F (1.06 ± 0.94) were significantly lower than in Group A (1.66 ± 0.90, p = 0.033); however, no different from Group D (0.92 ± 1.13, p = 0.807).ConclusionThis CPB method is a promising alternative to the CPB method using antegrade descending aortic perfusion for paediatric aortic arch repair.Trial registrationUMIN000052933.

Effects of using a finned cylindrical cooler in the nano-enhanced cooling channel on the exergetic performance of a PV/TEG-coupled system

ABSTRACT In this study, three different nano-enhanced channel models were integrated into the 3D photovoltaic (PV)/thermoelectric generator (TEG) system and the effect of the channel models on the PV/TEG system performance was examined. The flat rectangular channel, Model 1 while the cylindrical and fin-reinforced cylindrical object accommodated in the flat rectangular channel are defined as Model 2 and Model 3, respectively. A comparison of water and ternary nanofluid with various nanoparticle (solid particle volume fraction between 0.01 and 0.03) loading was performed in each channel model. In addition, impacts of cooling fluids at different inlet temperatures (Tg between 25°C and 12.5°C) were considered in the simulations. Among different cooling channels, lowest PV cell temperature and the highest PV output power were obtained in Model 3. The highest PV power (0.51 W) was obtained with Model 3 with ternary nanofluid (%3 volume fraction) at Tg = 12.5°C. This value is is 3.66% and 4.03% higher than Model 2 and Model 1, respectively. Under the same conditions, TEG output power reached its highest value with Model 2 and it was followed by Model 1 and Model 3, respectively. With the reinforcement of fins to the cylindrical object, an improvement in thermal performance was achieved, but a decrease in total output power was observed.

Determining the equilibrium efficient frontier by proportional frontier shifting for data envelopment analysis with fixed-sum outputs

The equilibrium efficient frontier data envelopment analysis (EEFDEA) has been extensively used to evaluate efficiencies of the decision-making units (DMUs) with fixed-sum outputs. This study develops a new EEFDEA approach based on a proportional frontier-shifting strategy. Our approach applies an iterative procedure to find the equilibrium efficient frontier (EEF). Each iteration uses a proportional frontier-shifting model to improve an inefficient DMU to the efficient frontier by increasing its fixed-sum outputs. Meanwhile, the DMUs on the efficient frontier decrease fixed-sum outputs proportionally to ensure the total fixed-sum outputs are unchanged. Our theoretical developments show that the proportional frontier-shifting strategy is feasible and can finally obtain a unique EEF. The new approach allows DMUs to use their preferred input and output weights when determining the EEF. This generates an EEF that better aligns with real-world practices and avoids the need to construct it as a single hyperplane, as required by conventional EEFDEA methods. It also avoids unfair adjustments in fixed-sum outputs among the DMUs and eliminates the problem of peculiar efficiency evaluation results (i.e., some DMUs obtain extremely high, or infinity, efficiencies). Finally, we apply our approach to a case study of Chinese vehicle industry companies to demonstrate its usefulness and compare it with the previous representative approach.

The unprincipled principal: how Romania’s inconsistent research reform impacted scientific output

This study employs the synthetic control method to assess the effects of Romania’s 2016 research reforms on the nation’s research output. Prior reforms were unstable and led to persistent deviations from international publication practices, where a disproportionate share of national research was published in national journals and subsequently in conference proceedings. The 2016 reforms, which introduced rigorous publication quotas and criteria, including reduced emphasis on conference proceedings, were notably stable. However, these reforms coincided with a consistent reduction in research funding. To understand the impact of the tension between increased publication demands and reduced research funding, the study analysed changes in research output distribution before and after the reform, focusing on total scientific output, conference proceedings, and articles published in MDPI and non-MDPI journals. The results revealed a significant decline in overall scientific production following the intervention. This decrease can be attributed to two key factors. First, the shift away from conference proceedings was not fully compensated for by the increase in articles published in MDPI journals. Second, there was also a decline in the articles published in non-MDPI journals.

Enhancing bioethanol conversion from straw by a novel circulation promotion method

Crop straw, an inedible and abundant agricultural by-product, can be used for bioethanol production. However, ethanol conversion from straw is a series of complex processes and has encountered issues, which cause considerable restriction to the production of straw ethanol. Herein, the bioethanol conversion process was innovated. Ethanol as a reverse osmosis membrane accelerant was investigated to enhance the removal of inhibitors to increase ethanol production during conversion process. The results indicated that membrane accelerant used here could reduce the inhibitor retentions by 39.3 %–69.2 %. Then, an original innovation integrated method for the whole process of straw ethanol conversion was developed. The integrated method could increase 26.8 % the production of straw ethanol compared to the membrane process without an accelerant. A preliminary cost accounting indicated that the integrated method was economically feasible when total ethanol output exceeded 14000 kg. This study represents for the first time a circulation promotion method based on the whole process of straw ethanol conversion. The results showed that the integrated method was capable of effective conversion of straw ethanol.

Unlocking superior performance of broadband powerful mid-IR optical parametric amplifiers with a BaGa2GeS6 crystal pumped at 1.24 µm.

We report on the development of a tunable (1.5-6.5 µm) femtosecond optical parametric amplifier (OPA) based on a novel, to the best of our knowledge, BaGa2GeS6 (BGGS) crystal with a Cr:Forsterite pumping laser. Total conversion efficiency as high as 28% is achieved in a robust two-stage setup resulting in the generation of a 340-µJ 1.67-µm signal and 100-µJ 4.65-µm idler pulses. A 5-optical-cycles 94-fs 6-µm idler pulses are demonstrated with a propriate dispersion compensation by Ge and GaAs plates. An experimental estimate is given for the effective nonlinearity of a BGGS material, which for our nonlinear process reaches 19.5 pm/V for Type II phase matching. The crystal is additionally tested as a final amplifier in a high-energy OPA, where total output reaches 1.2 mJ with more than 40% conversion efficiency. The demonstrated high nonlinearity, high damage threshold, and chemical stability of the polished surface make BGGS crystal an ideal candidate for the development of high-energy OPAs with multi-millijoule pumping lasers.

Effects and mechanisms of armed conflict on agricultural production: Spatial evidence from terrorist violence in Burkina Faso

AbstractExtensive studies have been conducted on the link between armed conflict and agricultural production. However, the underlying mechanisms remain underexplored. A better understanding of these mechanisms could unpack the subsequent effects of conflict‐induced food and welfare shortages, as well as identify promising policy interventions. We study the effects of terrorist violence on household agricultural production in Burkina Faso and explore the underlying mechanisms. To achieve this, we combine nationally representative five‐year panel data on plots and households with spatial conflict data. Our analysis reveals negative and significant effects of terrorist violence on agricultural productivity and total output. Despite reducing cereal crop output, increased intensity of terrorist violence is significantly associated with higher production of cash crops, which require fewer inputs in Burkina Faso. Further investigations uncover that the decline in household agricultural productivity results from a significant decrease in the number of farming plots, land size, and short‐term production investments, including chemical fertilisers and pesticides. These findings remain robust across various alternative empirical specifications and measures of violence, offering insights that can help policymakers faced with similarly scaled armed conflict. For instance, ensuring a secure environment and providing reliable access to essential production inputs, such as chemical fertilisers and pesticides, can help support conflict‐affected household agricultural production during and after the violence periods.