Rotation Experiments Research Articles

Comparison of Learner Self-Evaluations to Preceptor Evaluations for Scored Activities on Introductory and Advanced Pharmacy Practice Experiences

Background: Development of successful, practice-ready pharmacists includes ensuring learners are self-aware and able to reflect on knowledge, skills, and abilities. Single-point rubrics allow for evaluators to provide specific, formative, and actionable feedback to learners while encouraging learner self-reflection. Though evidence indicates reflective practices are important in pharmacy education, there is a general lack of structure for implementation of reflective practices. The primary objective of this study was to compare learner self-evaluations to preceptor and pharmacy resident evaluations for scored learning activities completed on experiential rotations. Methods: This study compared learner self-evaluations to preceptor and pharmacy resident evaluations for three types of assignments completed during experiential rotations at a community teaching hospital. These assignments included clinical presentations, patient counseling, and written drug information responses. The primary endpoint was differences in overall scores between evaluators. Findings: A total of 68 learner evaluations were reviewed, with a majority (89.7%) completed by students on Advanced Pharmacy Practice Experiences. Overall, no significant difference emerged between student and preceptor evaluator scores, indicating that students are able to accurately self-reflect. Conclusion: Pharmacy students on experiential rotations demonstrated consistency in self-scoring and evaluation with preceptors on assignments related to presentations, drug information responses, and patient counseling.

Design and Experimental Research on Staggered Straw Cleaning Device for No-Till Seeding in Drip Irrigation Area

To solve the problem of straw cleaning and drip irrigation belt restoration for no-till seeding in drip irrigation areas, a staggered straw cleaning device was developed for no-till seeding, which is mainly composed of a front two-sided tine discs group, a drip irrigation belt laying mechanism, a middle single inner tine discs group, a rear single outer tine discs group. Different tine disc groups are set in longitudinal, transverse, and radial directions to move and throw the straw on the surface of the seeding strip. The critical parameters of the tine disc were designed and calculated, and the radius was determined to be 160 mm, the number of teeth was 12, and the theoretical working width was obtained. The movement and straw scattering process were analyzed, and the main influencing factors and the maximum straw scattering distances in the horizontal and vertical directions were determined. The interaction model of staggered tine discs group–straw–soil is established using the discrete element method (DEM). The forwarding speed, rotating speed, disc rake angle, and lateral distance of the middle tine discs were used as influencing factors, and the straw cleaning rate and the mass of straw returned in the drip irrigation coverage area were selected as the text indexes to carry out quadratic orthogonal rotation experiments. The quadratic regression model of the three sensitive parameters on the cleaning rate and the mass of straw returned in the drip irrigation coverage area was constructed and optimized. The optimal solutions were obtained: the forwarding speed was 9 km/h, the disc rake angle was 33.7°, and the lateral distance of the middle tine discs was 529 mm. The field validation test was carried out, and the results showed that the straw cleaning was 89.13%, the straw cleaning width of the seed strip was 527.2 mm, and the straw coverage rate of the drip irrigation area was 80.74%. This achievement can provide a reference for straw cleaning of no-till seeding under drip irrigation.

The effect of mycorrhiza-inoculated succession-planted main crop (maize-wheat) and cover crop rotation on soil organic carbon

There has long been intense pressure on input-based traditional agriculture due to the rising need for food. These kinds of agricultural techniques result in poorly managed soil-plant interactions that ultimately affect all living activities and human health by altering and destroying the soil's natural structure, rendering it infertile, and degrading soil quality. Research was carried out a study to find out how mycorrhizae-inoculated cover crops affected soil quality and growth metrics. The study to pot experiment was carried out under greenhouse conditions. Five different plant combinations (cover crop) patterns were inoculated with selected and indigenous mycorrhizae spores that were isolated from the rhizosphere soils of plants grown in three degraded soils. Five different cover plant combinations, such as A: Clover, Grass, Onion; B: Faba Bean, Grass, Safflower; C: Clover, Grass, Safflower, Faba Bean, Onion; D: Maize; and E: Wheat, were planted in 7 kg soil-containing pots with three replications. The seeds of different plants were planted per m2 surface of each pot, with the number of seeds per pot calculated depending on their sowing amount per hectare. Sixty days after planting, the plants were harvested by cutting 0.5 cm above the soil surface with scissors. In the second rotation experiment, after the harvest of the first rotation experiment, maize (Zea mays L.) was planted on the A, B, C, and D patterns, and wheat was planted on the E pattern. In the third rotation, wheat was sown on all pots after the second maize harvest. As a result of successive three-pot experiments on the same soils, were analyzed for the soil organic carbon (SOC) concentrations. In general, treatments with Funneliformis mosseae followed by indigenous mycorrhiza spores led to an increase in soil OC concentration compared to control treatments. SOC concentrations in Havutlu and Arık soils were higher than those in Avadan soil. Avadan is a highly eroded soil and has high lime content, high pH, and low soil fertility. When consecutively planted trials are examined, the soil SOC concentration increased from the first trial to the last trial for all soils. The obtained SOC results seem to partially support the research hypothesis. The results revealed that poorly managed soil requires rehabilitations with various combinations of cover crops.

Safe Utilization Effect of Passivator, Foliar Inhibitor, and Their Combined Application on Cadmium-contaminated Farmland

This study sought to explore the effects of passivator, leaf inhibitor, and their combination on cadmium （Cd）-contaminated farmland and to realize the safe utilization of cultivated land. Coconut shell biochar and calcium magnesium phosphate fertilizer were selected as soil passivators and foliar selenium fertilizer was used as a foliar inhibitor. The best combination was selected through a wheat-maize rotation experiment. The results showed that： ① The soil pH, organic matter content, and CEC could be improved to varying degrees by the application of passivators. ② The grain yield of wheat and maize increased to different degrees after the application of the passivator and foliar inhibitor. ③ The BFL treatment （biochar 1 800 kg·hm-2 +calcium magnesium phosphate 600 kg hm-2 + foliar inhibitor 3 L·hm-2） during the maize season had the best effect, which was significantly lower than that in CK by 13.85%. The effect of the BF treatment （biochar 1 800 kg·hm-2 + calcium magnesium phosphate 600 kg·hm-2） in wheat season was the best, which was significantly reduced by 11.21% compared with that in CK. ④ The BF treatment （biochar 1 800 kg·hm-2 + calcium magnesium phosphate 600 kg·hm-2） had the best effect on reducing Cd content in roots, straws, and grains of maize and wheat, reducing Cd content in roots of wheat and maize by 20.55% and 27.81%, Cd content in straws by 11.39% and 13.70%, and Cd content in grains by 48.97% and 50.44%, respectively. Therefore, considering all the indexes, the combination of passivators and foliar inhibitor, especially biochar combined with calcium magnesium phosphate fertilizer and biochar and calcium magnesium phosphate fertilizer combined with foliar inhibitor, could more effectively reduce the absorption, transport, and enrichment of Cd in maize and wheat and could be popularized and applied in safe use cultivated land.

Road Performance of Cold Repaired Asphalt Mixture with New Green Maintenance Materials

Cold patched asphalt mixture plays a crucial role in road maintenance, providing flexibility and the ability to quickly recover from harsh weather conditions. This article conducts in-depth research on the performance of cold patched asphalt mixture through multiple experiments, with special attention paid to the influence of diluent content and curing conditions on its performance. The experimental results show that using a mixture of green curing agents is feasible, and the diluent content is one of the main factors affecting the physical properties of cold patched asphalt. The optimal content of asphalt diluent was determined to be 25% through mass evaporation experiments and rotational viscosity experiments. Meanwhile, it was found that single component polyurethane prepolymers and SBS curing agents have a negative impact on the adhesion of cold patched asphalt, but have an improving effect on its strength, high-temperature resistance, and water stability. After comparing the performance of cold patched asphalt mixtures under different curing conditions, it was found that the performance of cold patched materials with long-term curing was better. Finally, this study determined the optimal dosage ratio of base asphalt, bio oil diluent, and single component polyurethane prepolymer as 100:25:12, providing technical support for the design and application of cold patched asphalt concrete pavement under high adverse weather conditions.

Optimal nitrogen management increased topsoil organic carbon stock and maintained whole soil inorganic carbon stock to increase soil carbon stock—A 15-year field evidence

Nitrogen application significantly impacts soil organic carbon (SOC) and soil inorganic carbon (SIC) stocks, both of which are crucial for soil carbon sequestration. However, the effects of nitrogen fertilizer on the dynamics of SOC and SIC stocks remain poorly understood. Over a 15-year wheat-maize rotation experiment conducted on calcareous alluvial soil in temperate continental monsoon climate, we quantitatively analyzed crop carbon return and dynamics of SOC and SIC stocks among soil layers. Compared to conventional nitrogen management (Con.N), optimal nitrogen management (Opt.N) increased crop carbon return by 130 kg C ha−1 yr−1. There was no significant difference in SOC stock between Opt.N and Con.N, despite Opt.N used 39.4 % less nitrogen input compared to Con.N. In the topsoil, Opt.N maintained SIC levels similar to those of the Control and significantly increased by 7.22 % compared to Con.N. The Con.N treatment reduced SIC stock by 10.1 % compared to the Control. Furthermore, Opt.N had no significant negative effect on SIC stock in subsoil, thereby maintaining the whole SIC stock. After 15 years, Opt.N achieved a soil carbon stock of 52.7 Mg C ha−1, outperforming Con.N. SOC dominated the topsoil carbon stock, while SIC played a more crucial role in the subsoil. Overall, Opt.N outperformed Con.N in terms of the combined SOC and SIC stocks. Our findings suggest that Opt.N can enhance soil carbon stock with lower resource consumption, thereby contributing to global warming mitigation and promoting sustainable low-carbon agriculture.

Ti4Ir2O : A time reversal invariant fully gapped unconventional superconductor

Here we report muon spin rotation (μSR) experiments on the temperature and field dependence of the effective magnetic penetration depth λ(T) in the η-carbide-type suboxide Ti4Ir2O, a superconductor with a considerably high upper critical field. The temperature dependence of λ(T), obtained from transverse-field (TF)-μSR measurements, is in perfect agreement with an isotropic fully gaped superconducting state. Furthermore, our ZF μSR results confirm that the time-reversal symmetry is preserved in the superconducting state. We find, however, a remarkably small ratio of Tc/λ0−2∼1.22. This value is close to most unconventional superconductors, showing that a very small superfluid density is present in the superconducting state of Ti4Ir2O. The presented results will pave the way for further theoretical and experimental investigations to obtain a microscopic understanding of the origin of such a high upper critical field in an isotropic single-gap superconducting system. Published by the American Physical Society 2024

Unveiling nodeless unconventional superconductivity proximate to honeycomb-vacancy ordering in the Ir-Sb binary system

Vacancies in solid-state physics are underexplored in materials with strong electron-electron correlations. Recent research on the Ir-Sb binary system revealed an extended buckled-honeycomb vacancy (BHV) order. Superconductivity arises by suppressing BHV ordering through high-pressure growth with excess Ir atoms or Rh substitution, yet the superconducting pairing nature remains unknown. To explore this, we conducted muon spin rotation experiments on Ir1−δSb (synthesized at 5.5 GPa, Tc = 4.2 K) and ambient pressure synthesized optimally Rh-doped Ir1−xRhxSb (x=0.3, Tc = 2.7 K). The exponential temperature dependence of the superfluid density suggests a fully gapped superconducting state exists in both samples. The ratio of Tc to the superfluid density resembles that of unconventional superconductors. A significant increase in the superfluid density in the high-pressure synthesized sample correlates with Tc, indicating that unconventional superconductivity is intrinsic to the Ir-Sb binary system. These findings, along with the dome-shaped phase diagram, highlight IrSb as the first unconventional superconducting parent phase with ordered vacancies, requiring further theoretical investigations.

Investigating the Effects of the Height-to-Diameter Ratio and Loading Rate on the Mechanical Properties and Crack Extension Mechanism of Sandstone-Like Materials

The causes of the size effect (SE) and loading rate effect (LR) for rocks remain unclear. Based on this, a gypsum-mixed material was used to simulate sandstone, where the dosing ratio was 7.5% river sand, 17.5% quartz, 58.3% α-high-strength gypsum, and 16.7% water. The specimens were designed to have a height-to-diameter ratio (HDR) of 0.6~2, and three strain rates (SRs)—static, quasi-dynamic, and dynamic—were used to perform single-factor rotational uniaxial compression experiments. PFC2D was used to numerically simulate the damage pattern of a sandstone-like specimen. The results showed that the physical parameters did not change monotonically, as was previously found. The main reason for this is that the end-face friction effect (EFE) is generated when the dynamic SR or the HDR is 0.6~1, with a damage pattern of “X”. Under mechanical analysis, the power consumed by the EFE was inversely proportional to the HDR and directly proportional to the LR, and it can reduce the actual amount of energy transferred inside the specimen. This paper may provide a foundation for the study of non-linear hazards in coal and rock.

Analysis of the phytoremediation potential, rice safety, and economic benefits of light to moderate Cd-contaminated farmland in oilseed rape-rice rotation with straw removal: A three-year field trial

Under the dual pressures of food security and soil cadmium (Cd) pollution in China, the use of an oilseed rape-rice rotation system and phytoremediation has been proposed as an effective measure to extract heavy metals from soil, achieve safe rice production, and alleviate soil heavy metal stress. A three-year field rotation experiment by straw removal was conducted in light to moderate Cd-contaminated soil in Hunan, China. The experiment involved rotating two oilseed rape varieties, LSYH and ZYZ, with two rice varieties, the low-accumulation variety XWX and the high-accumulation variety TYHZ. The structural equation model (SEM) indicated that the correlation coefficients of total nitrogen (N) and available phosphorus (P) with CaCl2-Cd in the soil under oilseed rape-rice rotation were higher than those in rice monoculture, indicating that changes in soil nutrients have a significant impact on CaCl2-Cd during rotation. During continuous rice monoculture, the Cd content in brown rice exceeded safety standards in all three years. Crop rotation effectively reduced the Cd content in the aboveground parts of rice, particularly inhibiting its transfer to brown rice. By the second year of rotation, the minimum Cd content in brown rice from XWX and TYHZ was only 0.10 and 0.11 mg kg⁻1, respectively. Cd levels in rice met the safety standard (<0.2 mg kg⁻1). Although the Cd content in the third-year rice was higher than in the second year, it remained significantly lower than in the first year. The TPE in the aerial portion for the ZYZ-XWX rotation was 4.88%, while for the rotation of ZYZ-TYHZ rotation, it was 6.37%. Economic benefits were enhanced by this rotation mode, with profit-to-cost ratios exceeded 1. Overall, oilseed rape-rice rotation is an economical and environmentally friendly method for remediating soil Cd contamination, but it requires selecting the appropriate varieties.

A robust adaptive error state Kalman filter for MEMS IMU attitude estimation under dynamic acceleration

Accurate estimation of attitude (pitch, roll) is a prerequisite for ensuring safe navigation during vehicle control execution. In dynamic environments, the presence of acceleration often degrades the accuracy and robustness of attitude estimation using traditional algorithms with Micro-Electro-Mechanical Systems (MEMS) Inertial Measurement Unit (IMU). This paper proposes a robust adaptive error state Kalman filter (RAESKF) algorithm for attitude estimation of MEMS IMU under dynamic acceleration conditions. The RAESKF algorithm decomposes the true attitude Direction Cosine Matrix (DCM) into nominal and error components. An error state Kalman filter is utilized to fuse real-time measurements from MEMS gyroscope and accelerometer, estimating the error component, which is then used to correct the nominal attitude DCM. Furthermore, within the error state Kalman filtering framework, a dynamic acceleration robust adaptive adjustment strategy is implemented. This strategy relies on real-time data monitoring, threshold-based decision-making, and switching mechanisms. It adaptively selects between dynamic acceleration model compensation and online adjustment of the measurement noise covariance matrix. The primary objective of this strategy is to mitigate the impact of disturbance induced by dynamic acceleration on attitude estimation, thereby enhancing the accuracy and robustness. Laboratory rotation experiments have demonstrated that the algorithm improved pitch and roll measurement accuracy by at least 8.81% and 11.69%, respectively, under rotational conditions. In dynamic acceleration conditions, pitch and roll measurement accuracy improved by at least 42.76% and 67.21%, respectively.

Simulation analysis and experimental research on static performance of water-hydraulic pressure difference control valve

Many hydraulic tools, like hydraulic cylinders and hydraulic artificial muscle joints are operated by adjusting pressure differences between different zones. Typically, the method employed to change the pressure difference is establishing hydraulic bridges and adjusting liquid resistance. While effective, this method's drawback is complex structures. To address this issue, a water-hydraulic pressure difference control valve, integrating two hydraulic bridges, was designed. The static performances including the output pressure difference, the flow rate and the force acting on the valve core were analyzed using AMESim and computational fluid dynamics simulations. Based on the simulation results, a prototype of voice coil motor direct drive pressure difference control valve was manufactured and the corresponding experiments were carried out. The computational fluid dynamics simulation results show that the internal leakage and the through-flow capacity difference between throttling grooves affect the flow field characteristics of the valve. When the pump pressure is 3 MPa and the valve opening is at the middle position, the internal leakage increases the flow rate from 2.25 L/min to 2.38 L/min, and the through-flow capacity difference reduces the control port pressure from the theoretical analysis of 1.5 MPa–1.41 MPa. Furthermore, combined with the analysis of the external liquid resistance, the AMESim model of the pressure difference control valve is modified. When the pump pressure is 3 MPa, the pressure difference and flow rate average deviations between the modified AMESim model and the experiment are 0.021 MPa and 0.048 L/min. Finally, a rotational angle experiment for a water hydraulic artificial muscle joints showed satisfactory control effects, suggesting the valve's application in controlling hydraulic tools and actuators.

Pharmacy Students’ Self-Reported Cultural Competence in a Pharmacy Curriculum by Academic Year

ObjectiveThis study aims to explore the results of a Cultural Competency Assessment of Pharmacy Students (CCAPS) survey to identify areas where cultural competence content in one college of pharmacy curriculum can be improved. MethodsThe 39-item CCAPS survey was developed and administered to Doctor of Pharmacy (PharmD) students from July 2022 (after the end of the didactic curriculum and at the beginning of experiential rotations for fourth-year students) to October 2022 (at the beginning of the fall semester for first-year, second-year, and third-year students). Self-perception of cultural competency items were selected from the Cultural Competence Assessment Instrument and the Clinical Cultural Competency Questionnaire items. Responses were collected anonymously and analyzed in the aggregate by academic year using SPSS. ResultsA total of 541 students participated, with ethnicities including White/European American (26.6%), East/South/Southeast Asian (17%, 18.5%, 5.4%), Arab/Middle Eastern (17.9%), African American/Black (6.7%), and Hispanic (6.1%). Two-thirds of respondents identified as “very or extremely” culturally competent, and 78% reported comfort interacting with culturally diverse patients. Students scored lower on questions that assessed their comfort interacting with patients who have limited English proficiency or who refuse medications due to cultural reasons. Students in the fourth year reported more difficulty practicing skills related to cultural competency in their daily lives compared with students in other years. ConclusionUsing the CCAPS survey annually could help evaluate the cultural competency of pharmacy students across different academic years and identify gaps in the curriculum related to cultural competency.

枸杞振采收集过程中果实碰撞损伤分析与试验

Lycium barbarum L. (L. barbarum) is an economic crop with high added value and profit. Vibration harvesting is a suitable mechanized harvesting method for L. barbarum. It bruises easily during harvesting due to the softness and vulnerability of fresh ripe fruit, resulting in economic losses. This study analyzed the fruit drop and collision during vibration harvesting. High-speed photography was used to obtain the impact speed and angle of the falling fruit, and a kinematic analysis of the collision with the collection surface was conducted. The majority of the fruit had an impact speed of 2-6 m/s and an impact angle of 30-90° with the collection surface. A drop test was conducted to assess fruit bruising, and the impact speed was converted to the drop height. A orthogonal rotation experiment was conducted, and mathematical model was established between the drop height, impact angle, and impact material, and the fruit bruise rate, maximum impact force, recovery coefficient, and impact time. The effects of the factors on the fruit bruise rate, maximum impact force, recovery coefficient, and impact time were analyzed. The test results show that a vibration harvesting device for L. barbarum should be designed to reduce the height between the fruit and the collection surface and utilize a tilted collection surface and high cushioning materials to reduce the fruit bruising. This study provides guidance for subsequent research on the bruising of L. barbarum during vibration harvesting and harvester design.

Greenhouse gas emissions and crop-specific emission factors of eight upland crops based on a six-year field experiment in the North China Plain

Nitrous oxide is a significant greenhouse gas (GHG) contributor in crop production, yet detailed documentation, including crop yields and specific emission factors (EFd of N2O), are lacking for the North China Plain. A six-year (2016–2022) diversified crop rotation experiment in this region examined GHG emissions from eight crops (sweet potato, peanut, soybean, spring maize, sweet sorghum, ryegrass, summer maize, and winter wheat) and fallow seasons. The results revealed that summer maize had the highest cumulative soil N2O emissions (5.07 kg N ha−1), with an average flux value of 225.3 μg N2O-N m−2 h−1 during the growing season. Summer maize emitted 16–75 % more N2O than spring crops and winter wheat and 85–86 % more than ryegrass (cover crop) and the winter fallow season. All eight crops acted as weak net CH4 sinks. Annual average CO2-equivalents of N2O and CH4 emissions reflected N2O emissions from all crops and fallow seasons. In addition, GHG footprint metrics (GFa, per unit area; GFy, per kg equivalent yield; GFb, per kg biomass; GFe, per unit economic benefit) based on life cycle assessment thinking showed that intensive cereal crops (winter wheat and summer maize) had the highest GHG footprints, while sweet potato had the lowest due to its greater biomass and lower N input. Other crops had 19–90 % lower GHG footprints than wheat and maize. Furthermore, we also quantified specific-crop EFd of N2O, with ryegrass having the lowest EFd (0.48 ± 0.02 %), followed by winter wheat (0.81 ± 0.43 %), and other crops ranging from 1.00 ± 0.13 % to 2.36 ± 0.85 %. This study provides important emissions data for different crops and winter fallow periods, enhancing our understanding of GHG footprints and emission factors, which are essential for the advancement of sustainable agriculture practices.

Effects of leguminous green manure-crop rotation on soil enzyme activities and stoichiometry

Abstract As a crucial strategy for sustainable agricultural production, green manure-crop rotation can regulate soil nutrient cycling and decrease the reliance on nitrogen fertilizers. However, we still lack a comprehensive understanding of the changes in soil eco-enzyme activities, microbial metabolism, and nutrient limitations caused by leguminous green manure crop rotation. Here, we conducted field experiments of leguminous green manure-crop rotation across China to analyze soil extracellular enzyme activities, specifically β-glucosidase (BG), N-acetyl-β-D-glucosaminidase (NAG), leucine aminopeptidase (LAP), and acid phosphatase (AP). The study revealed that long-term green manure-crop rotation increased carbon and nitrogen accumulation in farmland, with a significant average increase of 20.1% and 36.4% in BG, AP enzyme activities in topsoil, while showing a decrease in ln(NAG+LAP):ln(AP) ratios. The ratios of ln(BG):ln(NAG+LAP) and ln(NAG+LAP):ln(AP) in soil across various regions were typically below 1:1, indicating that soil microbial activity is more constrained by nitrogen and phosphorus nutrients rather than by carbon. Precipitation, temperature, soil total carbon, and total nitrogen were identified as key environmental factors for extracellular enzyme activities and stoichiometric ratios. Our study highlights that the green manure-crop rotation alleviates nitrogen limitation while enhancing phosphorus limitation, and is closely related to the accumulation of total carbon and nitrogen in the soil.

Thiophene‐Based Multi‐layered 3D Chiral Polymer and Oligomer Containing Aggregate‐Induced Emission and Polarization

AbstractThiophene‐based conjugated polymers show a unique position in the constantly expanding variety of conjugated polymers because of their outstanding optical and conductive characteristics. during the past few decades, many researchers have made significant contributions by developing new methods to create more effective materials for electronic applications. Employing one‐pot Suzuki polycondensation, a unique series of structurally condensed multicolumn/multilayer 3D polymers and oligomers have been developed and synthesized in this research. Polymers were produced with moderate to excellent yields in all instances, as examined by GPC and 1H‐NMR. The results from experiments of optical rotation and AIE investigation, show that the current work will benefit materials research and applications.

α-pyrone derivatives from the endophytic Fusarium sp. L33 isolated from Dioscorea opposita

Two new α-pyrone derivatives, fusaripyrones C and D (1 and 2), along with six known compounds, namely phomapyrone C (3), fusarilactone A (4), pleospyrone D (5), 5-hydroxy-7-(2′-hydroxypropyl)-2-methyl-chromone (6), phenylacetic acid (7), and p-hydroxyphenylacetic acid (8) were isolated from Fusarium sp. L33, an endophytic fungus isolated from the leaves of Dioscorea opposita. Their structures were elucidated by NMR spectra, HRESIMS, optical rotation experiments and single-crystal X-ray diffraction analysis. Compounds 2, 3, and 6 were evaluated for their cytotoxic activity against five selected human tumor cell lines.

The impact of climate and potassium nutrition on crop yields: Insights from a 30-year Swiss long-term fertilization experiment

Climate change will strongly influence agricultural practices in the future. In order to promote resource-efficient agriculture, it is important to analyse the impact of climate variation on crop yields. In this study, we report yields of spring wheat, winter barley, maize, potato and sugar beet from the long-term crop rotation and fertilization experiment Demo in Switzerland and analyze their response to different climate variables (e.g., annual and seasonal temperature, precipitation, evapotranspiration, number of heat days and days of heavy rainfall). In addition, we investigate the impact of readily plant-available soil potassium (K) on the relationship of crop yields and precipitation. Annual and summer temperatures increased by 1 °C and 1.5 °C, respectively, over the observation period, and both the number of heat days and days of heavy rainfall increased in summer. Rising summer temperatures have a negative impact on all crop yields, which was most prominent for spring wheat, potato and maize. Annual, spring and summer precipitation show varying effects on different crops. For maize, soil K has a mediating effect on yield reductions under low spring precipitation. Yields are significantly reduced by 1 t ha−1 per 100 mm reduction of precipitation below a soil K threshold of 7 mg K kg−1 soil. Based on these results and the future climate scenarios for Switzerland, crop rotations with less heat-sensitive species and early-maturing varieties should be considered. In order to keep future irrigation demands and costs as low as possible, the soil K fertility classes in the Swiss K fertilization guidelines might need to be revisited. Our study is one of a few long-term observations that show the impact of climate variation on crop yields and highlights the potential of K management as a climate change adaptation measure.

Improving the beam quality of the low-energy muon beamline at Paul Scherrer Institute: Characterization of ultrathin carbon foils

The low-energy muon (LEM) beamline at the Paul Scherrer Institute currently stands as the world’s only facility providing a continuous beam of low-energy muons with keV energies for conducting muon spin rotation experiments on a nanometer depth scale in heterostructures and near a sample’s surface. As such, optimizing the beam quality to reach its full potential is of paramount importance. One of the ongoing efforts is dedicated to improving the already applied technique of single muon tagging through the detection of secondary electrons emerging from an ultrathin carbon foil. In this work, we present the results from installing a thinner foil with a nominal thickness of 0.5 μg cm−2 and compare its performance to that of the previously installed foil with a nominal thickness of 2.0 μg cm−2. Our findings indicate improved beam quality, characterized by smaller beam spots, reduced energy loss and straggling of the muons, and enhanced tagging efficiency. Additionally, we introduce a method utilizing blue laser irradiation for cleaning the carbon foil, further improving and maintaining its characteristics. Published by the American Physical Society 2024