Small-scale Field Experiments Research Articles

Teaching in a collaborative mathematic learning activity with and without a social robot

AbstractThere is a growing interest in whether social robots, which are embodied and exhibit human-like behaviour, can be used for teaching and learning. Still, very few studies focus on the teacher’s role. This study focuses on how a teacher acted in a learning-by-teaching activity with 20 children. In this small-scale field experiment, the teacher’s interactions and teaching actions were observed when the teacher scaffolded a learning activity where children played a collaborative digital mathematics game to strengthen their mathematical reasoning and conceptual understanding of arithmetic. When playing, the children were acting as tutors for a tutee, according to the learning-by-teaching principle. In one scenario, the tutee was a younger child; in the other, the tutee was a social robot. Twenty 30-minute game-playing sessions are observed, video-recorded, and transcribed. The study explores the teacher’s interactions and teaching actions in the two scenarios and discusses the results from the perspective of the teacher’s role, social norms, and teacher digital competence. The interaction and thematic analyses show similarities and characteristic differences in the teacher’s interaction patterns in the two scenarios. The teaching actions are similar on a structural level and differ regarding the types and distribution of teaching actions. In the child-child scenario, the teacher directs most teaching actions to both players, and the actions are didactic (mathematical) scaffolding. In contrast, in the child-robot scenario, the teacher only addresses the tutor, and the scaffolding is socially oriented. Implications for a teaching practice involving social robots as learning companions are discussed regarding teachers’ presence and participation, types of social robot knowledge that go beyond digital competence, and new challenges introduced by using social robots as learning companions in the classroom. The study contributes new insights into the teacher’s role and actions when teaching with a social robot in a collaborative learning situation, which is relevant for educational research and teaching practice.

Underwhelming pleasures: Toward a self-regulatory account of hedonic compensation and overconsumption.

Hedonic overconsumption (e.g., overconsumption of gratifying behaviors, e.g., eating, gaming) is common in daily life and often problematic, pointing to the need for adequate behavioral models. In this article, we develop a self-regulatory framework proposing that when an actual consumption experience falls short of hedonic expectations-such as when being distracted-people will want to consume more to compensate for the shortfall. In a preliminary meta-analysis, a small-scale field experiment on distraction during lunch and subsequent afternoon snacking (Study 1), and a preregistered experience sampling study (Study 2) involving more than 6,000 consumption episodes in everyday life across multiple consumption domains, we investigated the predictions from our hedonic compensation model. There was clear and consistent evidence across studies and analyses for the prediction that distraction during consumption compromises the actual enjoyment of a given consumption experience. Both empirical studies yielded consistent evidence for a positive association between actual enjoyment and consumption satisfaction but inconsistent and weaker evidence for the expected role of actual-expected enjoyment discrepancies for this part of the model. There was also consistent evidence for the expected negative association between consumption satisfaction and the need for further gratification. Finally, there was moderate and inconsistent support linking the need for further gratification to subsequent consumption across Study 1 (amount and frequency of snacking in the afternoon) and Study 2 (shorter duration to subsequent consumption). Taken together, the present framework provides initial support for the proposed link among compromising consumption contexts, consumption enjoyment, and subsequent hedonic compensation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Contribution of Antioxidant System Components to the Long-Term Physiological and Protective Effect of Salicylic Acid on Wheat under Salinity Conditions.

Salicylic acid (SA) plays a crucial role in regulating plant growth and development and mitigating the negative effects of various stresses, including salinity. In this study, the effect of 50 μM SA on the physiological and biochemical parameters of wheat plants under normal and stress conditions was investigated. The results showed that on the 28th day of the growing season, SA pretreatment continued to stimulate the growth of wheat plants. This was evident through an increase in shoot length and leaf area, with the regulation of leaf blade width playing a significant role in this effect. Additionally, SA improved photosynthesis by increasing the content of chlorophyll a (Chl a) and carotenoids (Car), resulting in an increased TAP (total amount of pigments) index in the leaves. Furthermore, SA treatment led to a balanced increase in the levels of reduced glutathione (GSH) and oxidized glutathione (GSSG) in the leaves, accompanied by a slight but significant accumulation of ascorbic acid (ASA), hydrogen peroxide (H2O2), proline, and the activation of glutathione reductase (GR) and ascorbate peroxidase (APX). Exposure to salt stress for 28 days resulted in a reduction in length and leaf area, photosynthetic pigments, and GSH and ASA content in wheat leaves. It also led to the accumulation of H2O2 and proline and significant activation of GR and APX. However, SA pretreatment exhibited a long-term growth-stimulating and protective effect under stress conditions. It significantly mitigated the negative impacts of salinity on leaf area, photosynthetic pigments, proline accumulation, lipid peroxidation, and H2O2. Furthermore, SA reduced the salinity-induced depletion of GSH and ASA levels, which was associated with the modulation of GR and APX activities. In small-scale field experiments conducted under natural growing conditions, pre-sowing seed treatment with 50 μM SA improved the main indicators of grain yield and increased the content of essential amino acids in wheat grains. Thus, SA pretreatment can be considered an effective approach for providing prolonged protection to wheat plants under salinity and improving grain yield and quality.

Long-term data reveal that grazer density mediates climatic stress in salt marshes.

Understanding how climate and local stressors interact is paramount for predicting future ecosystem structure. The effects of multiple stressors are often examined in small-scale and short-term field experiments, limiting understanding of the spatial and temporal generality of the findings. Using a 22-year observational dataset of plant and grazer abundance in a southeastern US salt marsh, we analyzed how changes in drought and grazer density combined to affect plant biomass. We found: (1) increased drought severity and higher snail density both correlated with lower plant biomass; (2) drought and snail effects interacted additively; and, (3) snail effects had a threshold, with additive top-down effects only occurring when snails were present at high densities. These results suggest that the emergence of multiple stressor effects can be density dependent, and they validate short-term experimental evidence that consumers can augment environmental stress. These findings have important implications for predicting future ecosystem structure and managing natural ecosystems.

Действие биопрепаратов на ростовые параметры Sorghum sudanense (Рiper) Stapf

Abstract. The purpose of the study was to study the effectiveness of microbiological preparations on the growth characteristics of Sudan sorghum under the conditions of the Vologda region on the background with and without fertilizers. Methodology and methods. Research work was first carried out in the Vologda region in the experimental field of FSBSI “Vologda Research Center of the Russian Academy of Sciences” in 2022. Biopreparations based on living cells of microorganisms were used, the basis of the drug “Naturost-Aktiv” consists of cell culture Lactobacillus buchneri, “Naturost-M” – Bacillus megaterium. The object of the study was Sudanese sorghum variety Zemlyachka. Small-scale field experiment included the following variants: control (1 var.), control + fertilizer (2 var.), biopreparation (3 var.), biopreparation 1 + fertilizer (4 var.), biopreparation 2 + fertilizer (5 var.). Repetition of the experiment – 3 times, the area of recording plot 5 m2. Indicators are presented by 4 counts per season. Results. The total bushiness in the variant with the “Naturost-Aktiv” increases by 35.3 %, an increase of 29.4 % to the control is noted in the variant “Naturost-Aktiv” + fertilizer. Productive bushiness was fixed in each variant, the maximum increase to the control was 45.5 % in the variant control + fertilizer. The greatest gain to the control of 42.5 % in the average area of the leaf surface was determined in the variant with the use of the drug “Naturost-M” and fertilization. Scientific novelty. For the first time a study on Sudan sorghum variety Zemlyachka in the conditions of the Vologda region using the biopreparation “Naturost-Aktiv” based on the cell culture Lactobacillus buchneri and “Naturost-M” – Bacillus megaterium on the background with and without fertilizers, which then can be recommended to increase the adaptation of plants and increase productivity, in turn Sudan sorghum can be recommended as a basic or auxiliary element of crop rotation.

Small-scale field experiment on wave forces on a U-OWC breakwater

A small-scale field experiment is conducted on a U-Oscillating Water Column (U-OWC) incorporated into a model of caisson breakwater at the Natural Ocean Engineering Laboratory (NOEL) laboratory of Reggio Calabria (Italy). The U-OWC or REWEC (REsonant Wave Energy Converter) is a device belonging to the family of Oscillating Water Columns (OWCs), characterized by the introduction of a U-duct. Such a device is innovative, absorbing a high percentage of incoming sea energy and, then, to produce electricity via a Power-Take-Off (PTO). The aim of the present study is the investigation of the wave pressures and forces acting on the U-OWC monolithic coastal defense structure. Moreover, the structural response of the U-OWC structure is also investigated under the occurrence of wave crests, by calculating the hydrodynamic forces realized in the active parts of the U-OWC. It is shown as a global additional force is realized, which contributes to increase the overall stability of the structure. Considering the wave loads acting on the U-OWC caisson, the post-process of the overall dataset recorded during the real field experiment at NOEL laboratory reveals the occurrence of both quasi-static loading (non-breaking), and of impact loading (impulsive) due to wave breaking. Thus, a systematic analysis is pursued in order to identify the loading cases acting on the U-OWC breakwater. When high non-breaking sea waves interact with the breakwater, “Quasi-Standing (QS)” wave pressures and forces occur at modified structure with two peaks of equal intensity. Instead, the impact of extreme breaking waves against the U-OWC structure generates asymmetrical wave pressure records beneath the wave crests, with two peaks with different intensity: the first one greater than the second one. In these cases, “Slightly Breaking (SB)” wave forces and “Impact Loads (IL)” are identified. Wave pressure distributions and forces acting on the U-OWC model are, then, investigated for the three classes of wave loads. Moreover, the probability of occurrence of maximum positive peak forces is determined from the experimental dataset, given a number of parameters. In particular, when QSWs occur, the maxima peak forces are recorded for deeper water depths dn, d’ and a, at given significant wave height HSi. Instead, for SBWs and ILs, the extreme wave loads are realized, when the most severe sea states occur with higher HSi , and for decreasing water depth dn. d’ and a. Then, the influence both of the length of the berm and of the width of the U-duct in the front structure is considered. When the dimensions of both structural elements is reduced, the maxima wave forces occur in a fixed recorded sea state. Then, the Quasi-Determinism (QD) nonlinear model at the U-OWC breakwater is introduced for evaluation of Quasi-Standing wave loads, showing a good agreement among analytical and experimental results. Finally, the Goda's model is applied to calculate the wave pressure distributions acting on the external walls of the U-OWC model. The theoretical results given by the Goda's formulae are compared with experimental data, overestimating experimental results for both QSWs and SBWs and, significantly, underestimating IL conditions.

The effect of online versus offline interventions on food safety and handling knowledge of household food handlers: A continuous experimental design

In China, 30–40% of foodborne diseases occur in households. Furthermore, compared with those in urban households, foodborne diseases are more prevalent in rural Chinese households, as evidenced by epidemiological data. The mastery of food safety and handling knowledge is considered crucial to ensure food safety, and this study represents the first exploration of food safety educational interventions for food handlers in the Chinese context. Knowledge-based interventions on food safety and handling were conducted among food handlers from 139 rural households. Over a two-month period, each participant received ten consecutive knowledge-based interventions, resulting in a total of 1390 interventions. Among them, 74 participants underwent online interventions, while 65 participants received offline interventions. Throughout the two-month intervention period, a questionnaire was administered to assess participants' food safety and handling knowledge four times: before the intervention, after the fourth intervention, after the eighth intervention, and after the tenth intervention. A total of 556 valid questionnaires were collected. The results indicated that both the online and offline interventions significantly improved participants’ knowledge levels. Knowledge scores increased from 13.54 to 20.93 points (out of 36 points) after 10 consecutive online interventions and from 13.89 to 22.00 points after 10 consecutive offline interventions. Furthermore, no significant difference in knowledge growth was observed between the online and offline intervention groups, although the growth rate decreased with increasing intervention time. These findings suggest that in the Chinese context, stakeholders can use the WeChat platform to design high-efficiency and comprehensive food safety knowledge-based interventions. Additionally, optimal intervention frequency and intensity can be determined through small-scale field experiments before launching large-scale campaigns.

Characteristics of carbon dioxide fracturing in comparison to conventional water hydraulic fracturing: Evidence from acoustic emission monitoring of small-scale field experiments

We conducted small-scale field hydraulic fracturing (HF) experiments using carbon dioxide (CO2) and water as fracturing fluids. A hole was drilled 10–14 m below the tunnel floor into hot granitic rock whose temperature can form CO2 supercritical state at HF pressure. Under the same injection rate of 10 mL/min, the volume of the acoustic emission (AE) hypocenter distribution induced by CO2 HF was approximately 27 times larger than that induced by water HF. In addition, when evaluating injectivity improvement through Injecting/Fall-Off Tests (IFOTs) using gaseous CO2 and water before and after CO2 HF and water HF, respectively, the injectivity of rock around the HF hole was improved by around 400 times larger by CO2 HF in comparison to a few times larger by water HF. The results suggest that CO2 HF can stimulate a much larger region and improve injectivity much more than water HF. In contrast, it has more possibility of leaking injected fluid through the stimulated region. On the other hand, when comparing the focal mechanisms of AE events in both CO2 HF and water HF with their occurrence times and locations, we found a tendency for tensile-dominant events to occur in intact rock, in contrast, shear-dominant events occur with a linkage between cracks, that is, the interaction of cracks. This finding suggests a solution for the paradox of the mechanism of HF in which shear events dominate in AE monitoring in actual production fields where there are various discontinuities and cracks, although the elastic theory expects tensile fractures.

Trait-based cropping of brassicaceous plants: Effects on ecosystem services and crop yield

Diversification of agroecosystems through mixed cropping can facilitate multiple ecosystem services that may improve yields. Intercrops may repel pests and nourish natural enemies while trap crops lure pests away from target crops. A small-scale agricultural field experiment was conducted in 2018 and 2020 in Finland to study how intercropping of brassicaceous plants and faba bean (Vicia faba) affects yield and quality of a target crop (white cabbage (Brassica oleracea var. capitata)), herbivory on the target crop, and effects of the insect communities linked to the observations. The study was conducted with five different plot arrangements in each year. Broccoli (Brassica oleracea var. italica) or turnip (Brassica rapa var. rapa) were located at the perimeters of 6 × 6 m plots as trap crops. They were planted either alone or with yellow rocket (Barbarea sp). Faba bean was planted as an intercrop in the most complex designs. Cabbage head fresh weight was greatest in the most complex plot type, which included cabbage, broccoli, yellow rocket and faba bean and the head weight was significantly greater than in the cabbage monocrop or the plots with a broccoli-only trap crop. Turnip was included in the experiment in 2020 and efficiently attracted flea beetles and pollen beetles. In 2020, the turnip trap crop alone and the most complicated designs with broccoli or turnip combined with yellow rocket and faba bean significantly reduced P. xylostella abundance in the middle of the plot. Possibilities to use trait-based cropping systems in white cabbage production are discussed.

Small-scale underwater explosion in shallow-water tank

The number of research studies on blast loads in the air is much larger than those under the water surface. Filling these deficiencies may increase the safety of marine structures, military divers and personnel working underwater. Studies on shallow-water tanks are especially omitted, while many large area seas can be classified in this category, for instance, the Baltic Sea.In the presented study, a military-grade blasting cap was placed in a shallow-water tank during small-scale field experiments. The pressure parameters and gas bubble formation were recorded. The pressure values were compared with high-speed images. The behavior of the blast wave due to the aquarium's bottom, surface, and vertical wall reflection was analyzed. The novel cavitation formation and its influence on pressure propagation in a limited water medium were described. Finally, a TNT equivalent based on the maximum gas sphere radius was calculated for further numerical research.

Combining two non-lethal methods in crossover design randomized experiments.

Abstract Wildlife control is the subfield pertaining to preventing threats to human property or safety from wild animals. Various research fields interact within wildlife control from animal behavior to agricultural management and other social sciences. We review understanding of the effectiveness of interventions using nighttime lights and fladry, both visual deterrents, to prevent carnivores from approaching livestock on working farms. We describe successes and failures in randomized. Controlled trials (RCT) with crossover design and the limits to inference and generalizability of their results. We present quantitative and qualitative evidence -- from two unpublished RCTs with crossover designs -- as a heuristic device to organize knowledge and highlight associated gaps. We focus on the sustainability of scientific wildlife control and collaborative research with farmers, material interventions, wildlife coexistence with livestock and people, and science communication. We conclude that small-scale field experiments will rarely achieve the statistical power to confidently generalize recommendations to use or avoid tested methods. Therefore, cautious experimental scientists who wish to avoid false discoveries or exaggerated claims may routinely experience constraints on promoting methods for wildlife control. The same constraints may not be felt by farmers or their allies, creating a tension in the science-policy interface between personal testimonials and scientific generalizations. We recommend steps that may fortify the science and enhance the sustainability of robust experimental designs under field conditions.

Methodology to measure the energy flux captured by a submerged U-OWC by using temperature sensors

The estimation of the power captured by a wave energy converters (WEC) device, needs to calculate the plant efficiency. In general, it is necessary to measure both the pressure and the discharge fluctuations of the fluid motion inside the plant. Unfortunately, gauges for the direct measurement of the velocity are bulky and provide punctual measures and, especially on converters having a U-duct, the presence of the velocity sensor produces a relevant disturbance on the motion field. To overcome this issue, an alternative method to evaluate the captured energy flux, using the pressure fluctuation and the air temperature inside the plenum, was proposed by [1] and [2]. However, no information about the accuracy of the temperature sensors and consequently about the errors in estimation of the energy flux were provided.
 In this work, following the procedure described by [1] and [2], we have analysed the influence of the time response of the temperature sensor in evaluating the variation of the air volume inside the chamber and, consequently the energy captured by the plant. To this aim, the submerged U-OWC, tested directly at sea in [1], has been simulated numerically. The aim of the numerical experiment is having the actual estimation of the air temperature inside the plenum and trough it, the captured energy flux. The computational domain is constituted by a wave-flume, with a piston-type wavemaker, placed at the left extremity and a submerged breakwater embedded a U-OWC plant, in the middle. The numerical 2D unsteady simulation is based on the Eulerian approach, using the commercial code Ansys Fluent v17.0, Academic Version.
 Starting from the knowledge of the pressure fluctuation at the upper opening of the vertical duct and, of both pressure and temperature variations of the air in the plenum, we have evaluated the energy flux absorbed by the plant and we have calibrated the mathematical model used in [1] and [2], using as input the time series of the pressure fluctuations at the upper opening of the vertical duct, and the variation of both temperature and pressure of the air inside the chamber. Then, using the time series of the actual air temperature, we have simulated the input of several first order temperature sensors characterized by different time constant t, and we have analysed the percentage differences in term of energy flux as a function of t.
 We have observed that the measurements of the temperature inside the plenum are strongly affected by time constant of the sensor, which produce large errors in the evaluation of the captured energy flux.
 Finally, we have proposed a method for conditioning the measure of the air temperature, obtaining an excellent estimation of the energy flux.
 
 Boccotti, P. (2003) "On a new wave energy absorber"Ocean Engineering 30(9), pp. 1191-1200.
 Arena, F., Filianoti, P. (2007),"Small-scale field experiment on a submerged breakwater for absorbing wave energy", Journal of Waterway, Port, Coastal and Ocean Engineering, 2007, 133(2), pp. 161–167.

Experimental field study on smoke characteristics and CO concentration of high-altitude tunnel fires induced using gasoline and diesel

High-altitude environments exhibit reduced atmospheric pressure, low oxygen density, and low air temperature conditions, which considerably affect tunnel fire characteristics. In this study, small-scale tunnel fire field experiments were performed at high altitudes to investigate the heat release rate (HRR), smoke temperature, and CO concentration of gasoline and diesel pool fires. The results revealed that with the increase in altitude, the HRR declined but the combustion duration increased. Furthermore, the maximum ceiling temperature decreased with the increase in altitude. The longitudinal ceiling temperature declined slowly in the high-altitude tunnel. By contrast, the smoke temperature spread rapidly among the cross-section in the high-altitude tunnel. The ceiling CO concentration behaviors for gasoline and diesel pool fires were categorized into four and three stages, respectively. Furthermore, the steady ceiling CO concentration and the maximum ceiling CO concentration decreased slightly with the increase in the altitude for gasoline pool fires, whereas the differences were greater for diesel pool fires. However, the steady ceiling CO concentration per unit mass burning rate increased linearly with the altitude for both fuels. The results revealed that the steady CO concentration at the height of 110 mm in the cross-section was nearly identical for various altitudes in the case of gasoline pool fires. However, for diesel pool fires, the CO concentration was higher at higher altitudes.

Discriminating the effects of bioturbation and herbivory by the intertidal burrowing crab Neohelice granulata on microphytobenthic assemblages of SW Atlantic mudflats

In shallow soft-bottom intertidal systems, microphytobenthic assemblages (MPB) and macrofauna interact and play important roles in ecosystem functioning. Macrofauna can affect MPB through bioturbation or/and herbivory. Most bioturbators also exert herbivory pressure on MPB, hence the results of the interaction between benthic macrofauna and MPB is not easy to predict. In this study we performed a small scale field experiment in order to discriminate the effect of bioturbation and herbivory by the intertidal burrowing crab Neohelice granulata on MPB structure, and primary production in SW Atlantic mudflats. The implemented treatments allowed us to separate the effects of bioturbation from those of herbivory on MPB. Results showed that N. granulata, through bioturbation + herbivory did not affect MPB structure (i.e., biomass, abundance and composition); and crab bioturbation without herbivory also did not modify MPB structure. Nevertheless, crab bioturbation without herbivory almost doubled MPB primary production, compared to the values registered in the treatment without bioturbation and herbivory and the treatment with bioturbation + herbivory. Sediment properties were equally affected by bioturbation in the four treatments. Thus, our results shows that the only significant effect on MPB structure is due to crab bioturbation.

Seed Treatment with Sodium Nitroprusside Ensures a Long-Term Physiological and Protective Effect on Wheat under Salinity.

Although salinity inhibits plant growth, the use of a nitric oxide (NO) gasotransmitter can reduce its negative effects. In this study, the influence of 200 μM sodium nitroprusside (SNP) (donor of NO) on wheat plants (Triticum aestivum L., cv. Salavat Yulaev) in conditions of salinization (100 mM NaCl) was analyzed in pot experiments. Seed priming regulated the level of endogenous NO in normal and salinity conditions throughout the entire experiment (30 and 60 days). Salinity led to the strong accumulation of NO and H2O2, which is negative for plants, and significantly reduced leaf area and photosynthetic pigments (chlorophyll a and b and carotenoids). In addition, stress caused a drop in the content of reduced glutathione (GSH) and ascorbic acid (ASA), an accumulation of oxidized glutathione (GSSG), and significantly activated glutathione reductase (GR), ascorbate peroxidase (APX), and lipid peroxidation (LPO) in wheat leaves. SNP treatment significantly attenuated the negative effects of salinity on leaf area and photosynthetic pigments. An important indicator of reducing the damaging effect of salinity on treated plants is the stabilization of the content of GSH and ASA throughout the experiment (60 days). This condition has been associated with long-term modulation of GR and APX activity. Such an effect of 200 μM SNP may be related to its ability to reduce stress-induced accumulation of NO. Additional accumulation of proline also mitigated the negative effect of salinity on plants, and this also evidenced decreased LPO and H2O2 in them. For the first time, in natural growing conditions (small-scale field experiments), it was found that pre-sowing seed treatment with 200 μM SNP led to an improvement in the main yield indicators and an increase in the content of essential amino acids in wheat grains. Thus, SNP treatment can be used as an effective approach for prolonged protection of wheat plants under salinity and to improve grain yield and its quality.

Пример алгоритма для расчёта специального лекарственного севооборота

The article presents a description of the algorithm in Word Excel format for calculating the structure of the small-scale field experiments areas as part of special medicinal crop rotation on the example of the VILAR experimental field (Moscow region) according to data for the period 2011-2021. The programming of the algorithm is implemented on the basis of conditional and logical operators. In the comments to the algorithm is given: a description of the hierarchical structure, criteria, types and relationships of data, the scheme of the algorithm, data features. The illustrations show the screen view of the algorithm, input and output data, the structure and location of data in the calculation table at different stages of using the algorithm. This algorithm is applicable for a system most similar to a crop rotation system with separate working areas within a crop rotation field of variable size. The results are relevant in the field of applied information technologies and scientific applied research for use in agricultural production in order to improve the efficiency of land use. Keywords: APPLIED INFORMATION TECHNOLOGIES, BRANCHING ALGORITHM, STRUCTURE OF CROP ROTATION AREAS, FIELD EXPERIENCE

Utilization of UAV Remote Sensing in Plant-Based Field Experiments: A Case Study of the Evaluation of LAI in a Small-Scale Sweetcorn Experiment

In crop production, which is largely dependent on environmental conditions, various attempts at environmental or social changes have been highlighted, and many field experiments are needed for them. However, since field experiments in agricultural production are constrained by high labor and time consumption, alternative methods to respond to these constraints are required. In this study, to establish a new method for application to field experiments, we proposed the evaluation of the leaf area index (LAI) of all individual plants in an experimental sweetcorn field using an unmanned aerial vehicle (UAV). Small-scale field experiments were conducted over two years. In the first year, the nitrogen fertilizer level was changed, and the plant density and additional nitrogen fertilizer application time were changed in the next year. Three vegetation indices (VIs), namely, the normalized difference vegetation index (NDVI), enhanced vegetation index 2 (EVI2), and simple ratio (SR), were validated to quantify the LAI estimation using a UAV for individual plants. For the evaluation of the individual plants, we used a plant-based method, which created all of the plant buffers based on the points of existing plants and the plant distance. To confirm the impact of the method, we additionally demonstrated the relationship between the LAI and yield, the results of statical analyses, and the difference of the center and the border of the field. Among the three VIs, index SR was found the most promising in the estimation of the LAI of the individual sweetcorn plants, providing the strongest correlation of yield with SR. Because a lot of data were obtained using the plant-based method, the statical differences in the LAI and yield were more easily detected for the plant density and fertilizer treatments. Furthermore, interesting differences between the center and the border of the field were found. These results indicate the availability and impact of plant-based evaluations using UAVs in near future field experiments.

Reduction of Cd Uptake in Rice (Oryza sativa) Grain Using Different Field Management Practices in Alkaline Soils.

Cadmium contamination and toxicity on plants and human health is a major problem in China. Safe rice production in Cd-contaminated alkaline soils, with acceptably low Cd levels and high yields, remains an important research challenge. To achieve this, a small-scale field experiment with seven different soil amendment materials was conducted to test their effects performance. Two best-performing materials were selected for the large-scale field experiment. Combinations of humic acid, foliar, and/or soil silicon fertilization and deep or shallow plowing were designed. It was found that the combination, including humic acid, soil and foliar silicate fertilization, and shallow plowing (5-10 cm), produced the most desirable results (the lowest soil bioavailable Cd, the lowest grain Cd concentrations, and the highest grain yield). Rice farmers are therefore recommended to implement this combination to attain high grain yield with low Cd concentrations in alkaline soils.

Experimental Investigation of Wave Loads on U-OWC Breakwater

A small-scale field experiment was conducted on a U-OWC incorporated into a caisson breakwater at the NOEL laboratory of Reggio Calabria (Italy). The U-Oscillating Water Column (U-OWC) or REWEC (REsonant Wave Energy Converter) is a device belonging to the family of OWCs. Such a device is very innovative, being able to absorb a very high percentage of incoming sea waves energy and to produce electrical power via proper PTO. The focus of the paper has been the analysis of the impact wave loads acting on the modified U-OWC structure during extreme wave events. A total of 250 records of pure wind waves were analyzed to verify the behaviors of wave loads acting on a U-OWC breakwater during operating conditions. The occurrence of both “quasi-standing wave” loads due to non-breaking waves and “impulsive wave loads”, exerted by a wave breaking against the U-OWC model, were observed. Then, Goda’s model was applied to predict the wave pressure distribution on the external wall of the U-OWC pneumatic chamber, and the theoretical results were compared to those obtained via small-scale field experiment.

Children's learning-by-teaching with a social robot versus a younger child: Comparing interactions and tutoring styles.

Human peer tutoring is known to be effective for learning, and social robots are currently being explored for robot-assisted peer tutoring. In peer tutoring, not only the tutee but also the tutor benefit from the activity. Exploiting the learning-by-teaching mechanism, robots as tutees can be a promising approach for tutor learning. This study compares robots and humans by examining children's learning-by-teaching with a social robot and younger children, respectively. The study comprised a small-scale field experiment in a Swedish primary school, following a within-subject design. Ten sixth-grade students (age 12-13) assigned as tutors conducted two 30min peer tutoring sessions each, one with a robot tutee and one with a third-grade student (age 9-10) as the tutee. The tutoring task consisted of teaching the tutee to play a two-player educational game designed to promote conceptual understanding and mathematical thinking. The tutoring sessions were video recorded, and verbal actions were transcribed and extended with crucial game actions and user gestures, to explore differences in interaction patterns between the two conditions. An extension to the classical initiation-response-feedback framework for classroom interactions, the IRFCE tutoring framework, was modified and used as an analytic lens. Actors, tutoring actions, and teaching interactions were examined and coded as they unfolded in the respective child-robot and child-child interactions during the sessions. Significant differences between the robot tutee and child tutee conditions regarding action frequencies and characteristics were found, concerning tutee initiatives, tutee questions, tutor explanations, tutee involvement, and evaluation feedback. We have identified ample opportunities for the tutor to learn from teaching in both conditions, for different reasons. The child tutee condition provided opportunities to engage in explanations to the tutee, experience smooth collaboration, and gain motivation through social responsibility for the younger child. The robot tutee condition provided opportunities to answer challenging questions from the tutee, receive plenty of feedback, and communicate using mathematical language. Hence, both conditions provide good learning opportunities for a tutor, but in different ways.