Field Conditions Research Articles

Development and Evaluation of a Variable-Rate Fertilizer Distribution System for Coffee Plants

Currently, Brazilian coffee farming seeks the rational use of resources through sustainable practices. As a result, the development of machinery with more efficient input application systems and the adoption of precision agriculture techniques have been yielding excellent results. This study was divided into two stages, with the first involving the adaptation of a solid fertilizer application machine with fixed doses, allowing dose variation using an electronic controller. The second stage consisted of conducting trials and their applications under operational conditions. The results confirmed that the developed system remained stable in terms of variable-rate fertilizer distribution for coffee cultivation. The machine’s lateral fertilizer distribution range met the demands of coffee farming satisfactorily. In field conditions, the developed system exhibited an average error of −2.9%, compared to the programmed doses, validating the accuracy of the machine and its suitability for use in coffee plantations.

Efficacy of a New Multivalent Vaccine for the Control of Bovine Respiratory Disease (BRD) in a Randomized Clinical Trial in Commercial Fattening Units

A new multivalent vaccine (DIVENCE®), containing live gE/tk double-gene-deleted BoHV-1, live-attenuated BRSV, inactivated PI3, and BVDV-1, and BVDV-2 recombinant proteins, has been designed to protect cattle against the main viral pathogens associated with bovine respiratory disease (BRD). The aim of this study was to demonstrate the efficacy of DIVENCE® against BRD in field conditions. A total of 360 animals from three different farms were included in this study. Calves were randomly distributed to the vaccinated (n = 183; DIVENCE®) or control (n = 177; phosphate-buffered saline solution) group. All animals received two intramuscular doses (2 mL/dose) three weeks apart of the corresponding product. The entire fattening period (approximately 9 months) was monitored to assess the incidence, severity, and morbidity of BRD as well as administered treatments and growth performance. During this study, a BRSV outbreak was reported in one farm, where vaccinated animals had significantly (p < 0.02) lower morbidity (20.4%) and severity (score of 1.70) compared to the control group (53.70% and score of 2.11). Overall, vaccinated animals had a significantly lower number of cases (p < 0.001; 0.36 vs. 0.64 cases/calf), lower morbidity (p < 0.004; 26.78% vs. 41.24%), and lower antimicrobial treatments (p = 0.01; 33.3% vs. 57.4%) than control animals. Vaccinated animals presented significantly (p = 0.01) higher carcass weight than controls (6.58 kg). Vaccination with DIVENCE® at the beginning of the fattening period decreased the incidence and morbidity of BRD following a BRSV outbreak. Additionally, the overall incidence and morbidity of BRD throughout the entire fattening period were reduced across farms. Thus, DIVENCE® can improve economic outcomes in fattening units by reducing antibiotic treatments and enhancing performance.

Subterranean termites (Coptotermes formosanus [Blattodea: Rhinotermitidae]) colonies can readily intercept commercial inground bait stations placed at label-prescribed distance

Abstract The Formosan subterranean termite, Coptotermes formosanus Shiraki, is both an economically impactful pest and a successful invader. One method of subterranean termite control is baiting. According to the label, baits are installed surrounding the structure at a uniform interval distance of ≈3 m. However, homeowners and pest control professionals are often concerned that termites may bypass bait stations and have access to the structure. To address this concern, we experimentally duplicated field conditions using a large planar arena (3.6 m × 1.1 m) to study the optimal distribution of bait stations based on colony-wide foraging activity. We installed 2 bait stations 3 m apart as per label instructions and introduced C. formosanus colonies to allow them to explore the arena by tunneling through the sand. In this real-scale arena, all termite colonies intercepted a bait station in an average of 21 (± 8 SD) days. We assumed that termites could find bait faster if there were more bait stations by overlaying additional hypothetical baits closer than per label instruction, but the improvement was incremental, requiring 4 times more stations (0.45 m interval) to obtain a significant difference. We also revealed the characteristic behavior after intercepting bait stations, termites created a burst of tunnels that radiated from the bait station. These branching tunnels averaged 16 cm in length, suggesting immediate interceptions of additional auxiliary stations placed within 16 cm of an active station. These findings contribute to our understanding on how subterranean termites intercept inground bait stations.

EFFECT OF SIDA CORDIFOLIA LINN. LEAF AND ROOT ETHYL ACETATE EXTRACTS ON THE GROWTH AND PHYSIOLOGICAL RESPONSE OF PANICUM REPENS AND PANICUM MAXIMUM

Due to the incessant application of synthetic herbicides in the agricultural system coupled with a rapid increase in herbicide-resistant weed species across the globe, much attention has been focused on alternative weed management, including allelopathy, which is eco-friendly and reduces reliance on synthetic herbicides. The effect of Sida cordifolia root and leaf ethyl acetate extract was evaluated under field conditions to determine its effects on growth, physiological response, stomatal index and density, and biochemical activity on weed species (Panicum maximum, Panicum repens, and Andropogon gayanus), as well as its effects on soil micronutrients. S. cordifolia root and leaf were collected from the wild in Nigeria and prepared into powder, which was dissolved to obtain the following concentrations 10, 20, 40, 60, and 80%, and distilled water served as the control. The percentage inhibition seems to be correlated with different growth indices as proven by an increase in malondialdehyde (MDA) content, reactive oxygen species (ROS), glutathione transferase (GST), and peroxidase (POD). Physiological growth indices such as plant height, leaf area, number of leaves, dry weight, stomatal density, and stomatal index were inhibited in both weed species while biochemical parameters such as Chlorophyll a, b, total chlorophyll and chlorophyll stability index were slightly reduced, increase in MDA, GST, ROS and POD were also noticed. In general, Andropogon gayanus showed a high inhibition rate compared to tomato. It is therefore recommended that concentrations of the Sida cordifolia extracts be increased to have a robust effect on the physiological processes of the weed species.

Influence of initial state and residual stresses on the modulus-density relationship of geomaterials: insights from multiple experimental setups

ABSTRACT Quality control in pavement construction traditionally relies on density measurements of geomaterials. With the introduction of modulus measurement methods, a shift has occurred due to the operational advantages of modulus-estimating devices over conventional density measurement techniques. Modulus-based methods also provide valuable information for the mechanistic-empirical (ME) design of pavement layers. However, a challenge emerges as a single modulus measurement does not directly correspond to a specific density measurement, leading to concerns about replacing density measurements in quality control processes. While it is generally accepted that a geomaterial's modulus primarily depends on its moisture content and density or void ratio, this study explores the complex relationship between modulus and density, particularly in field scenarios with consistent moisture content. Using three different laboratory-scale test set-ups, characterised by unique loading and boundary conditions, the research highlights the significant role of a geomaterial's initial state in obtaining accurate modulus estimates. The results reveal that identical densities can exhibit variations in modulus due to differences in initial densities and the development of residual lateral stresses. These variations in field conditions often stem from different paving or spreading techniques, emphasising the need for a comprehensive approach when establishing density-modulus correlations..

Efficacy of using grape cane extracts against <i>Plasmopara viticola</i> under field conditions and their impact on the composition of berries and musts of <i>Vitis vinifera</i> L. cv. Riesling

Grapevine downy mildew caused by Plasmopara viticola is a deleterious vine disease currently controlled using synthetic and copper-based fungicides. Environmental concerns surrounding such fungicides necessitate sustainable alternatives like grape cane extracts. However, studies into their efficacy and effects on the product remain limited. This study aimed to assess the open-field efficacy of a novel grape cane extract formulation, alone and combined with a copper agent, against downy mildew, and to examine its impact on berry and must composition. The results were compared to standard fungicides frequently used in integrated and organic viticulture. In 2022, the grape cane extract formulation reduced downy mildew severity by 78 % on berry clusters, comparable to the maximum acceptable dose of copper for organic farming in Germany (3 kg/ha/a). Combining the grape cane extract with the copper agent was more effective than the copper agent alone, but not more effective than the grape cane extract alone. In 2023, disease development was marginal, despite artificial inoculation. Compositional differences detectable by FTIR were insignificant between musts derived from all treatments, increased copper levels were observed whenever copper had been applied. The phenolic content in freeze-dried, de-seeded berries of 2022 was significantly lower after copper (14.6 mg/g dry weight DW) and grape cane extract treatments (6.6 mg/g DW) when compared to the control (36.1 mg/g DW), with discrepancies in stilbenoid and flavan-3-ol levels in particular, as analysed by HPLC-DAD. However, these differences were not confirmed in 2023, with results showing no correlations between different treatments and phenolic contents. These findings suggest that applications of the phenolic grape cane extract do not lead to artificially altered levels or relevant residues of the active constituents; i.e., the phenolic compounds in the product. In brief, grape cane extracts might represent a promising natural alternative to controlling grapevine downy mildew, particularly in organic viticulture, which, to date, heavily relies on (eco-)toxic copper-pesticides. Further multi-year studies including wine analyses are warranted to follow the entire flow towards the final product.

Characterization of four Acidovorax phages and their potential in phage biocontrol for lamb's lettuce seed decontamination.

Bacterial black spot, caused by Acidovorax valerianellae, is responsible for significant yield losses in lamb's lettuce (Valerianella locusta) in many producing countries, especially Europe. Currently, no resistant varieties of V. locusta are available that effectively control the disease under field conditions. Bacteriophage-based biocontrol has been suggested as a sustainable and natural alternative strategy to combat bacterial pathogens. In this study, novel phages infecting A. valerianellae and Acidovorax cattleyae, Alfacinha1, Alfacinha3, Acica, and Aval, were isolated and characterized. Based on comparative genomics, these phages represent three new phage genera. Aval and Acica phages revealed genomic features characteristic of temperate lifestyle, encoding toxins likely associated with lysogenic conversion, which contrasts with Alfacinha1 and Alfacinha3. The latter was selected for application as a biocontrol agent during seed steeping. This phage reaches an 87% reduction in the A. valerianellae concentration on artificially infested seeds. Importantly, this reduction results in an increased germination rate from 58.9% to 93.3%. Moreover, the infected seedlings had a dramatic reduction in vigor index after 22 days of growth, whereas the phage-treated ones had a vigor index similar to the negative control, reinforcing the ability of bacteriophages to effectively reduce disease progression. We further evaluated the impact of lipopolysaccharides in phage suspensions on the development of seedlings. Here, we demonstrated that the presence of lipopolysaccharides do have an impact on seedling development, significantly reducing the number of roots developed. This study shows how genomic analyses and tailored bioassays represent an essential route to ensure safe phage application and demonstrates the potential of a phage-based biocontrol strategy against A. valerianellae.IMPORTANCEBacteria continue to globally cause serious damage to a variety of crops. One example is a bacterial black spot of lamb's lettuce caused by Acidovorax valerianellae. It has spread across Europe, resulting in economic losses of at least 10% in tonnage annually. Faced with the inefficiency of conventional control methods, an alternative and sustainable strategy based on the use of bacteriophages was pursued in this study. We present for the first time the isolation and characterization of A. valerianellae-specific phages. Moreover, we assessed their biocontrol potential in seed decontamination since the disease primarily spreads from seeds to seedlings. Interestingly, seed treatment with one of our phages reaches an 87% reduction in bacterial concentration. More importantly, this reduction results in an increased germination rate from 58.9% to 93.3%. Finally, our study demonstrated for the first time the need for removing endotoxins from phage suspensions as they impact plant development when used as a biocontrol agent.

Effect of Herbal Liver-tonic Supplements on Production Performance in HF Dairy Cattle

A study was conducted to observe the influence of herbal liver-tonic supplementation on milk production, liver function and feed intake in HF crossbred dairy cattle at field level. This study was carried out in 24 HF cattle and these were randomly grouped into three groups viz. Group 1 served as control group, Group II served as Treatment -I (supplemented with polyherbal liver tonic @ 30ml/day) and Group III as Treatment-2 (supplemented with polyherbal liver tonic @ 45ml/day). Day 1 to 7 is considered as before treatment, Day 8 to 17 as treatment period and day 18 to 32 as after treatment. The blood collected during study period and stored at -20 °C until further analysis. The data were also regularly recorded for milk production, SNF Content of milk, feed intake. Statistical analysis of result revealed that herbal liver-tonic supplementation showed non-significant (P>0.05) difference on liver enzymes profile. Statistically no significant difference is also noted on milk production, milk fat and SNF Content in HF Cattle at field conditions.

Expression of Immunodominant gI Protein of Duck Enteritis Virus and its Evaluation for ELISA

Background: Duck plague (DP), also known as duck viral enteritis (DVE) caused by Anatid alpha herpesvirus-1, is the major infectious viral disease reported in India very often with significant economic losses due to high morbidity and mortality. The genome is approximately 158,091 bp with a genomic arrangement pattern (UL-IRS-US-TRS) that corresponds to type-D herpesvirus. The incubation period of the disease in domestic ducks ranges from 3 to 7 days and the mortality varies from 5-100%. It has been reported that the strategies to monitor and control DVE were often frustrating because the disease tends to establish a latent infection in waterfowl and vaccination failure. The present study was taken as an attempt to develop indirect ELISA using developed recombinant gI protein to diagnose DEV in field condition. Methods: In this study, we selected a membrane glycoprotein protein I (US7) gene, that plays an important role in virion sorting, cell-cell spread and binding of IgG Fc receptor. The gI protein was cloned with pET-32a (+) and expressed in a prokaryotic (E. coli) expression system. Further, recombinant protein was purified by nickel column affinity chromatography and refolded by dialysis. The obtained concentrated protein was then evaluated for its antigenicity and reliability in an Indirect-Enzyme-linked immunosorbent assay (ELISA) for DEV antibody detection in duck sera. Result: A panel of positive, negative and vaccinal serum was evaluated which indicated the potential use of the protein in the development of a serological assay for sero- surveillance of duck plague infection.

Nanoplatforms for Magnetic-Photo-Heating of Thermo-Resistant Tumor Cells: Singular Synergic Therapeutic Effects at Mild Temperature.

A self-assemble amphiphilic diblock copolymer that can incorporate iron oxide nanocubes (IONCs) in chain-like assemblies as heat mediators for magnetic hyperthermia (MHT) and tuneable amounts of IR780 dye as agent for photothermal therapy (PTT) is developed. MHT-heating performance of photobeads in viscous media have the same heat performances in water at magnetic field conditions of clinical use. Thanks to IR780, the photobeads are activated by infrared laser light within the first biological window (808nm) with a significant enhancement of photo-stability of IR780 enabling the raise of the temperature at therapeutic values during multiple PTT cycles and showing unchanged optical features up to 8 days. Moreover, the photobeads fluorescent signal is preserved once internalized by glioblastoma multiforme (GBM) cells. Peculiarly, the photobeads are used as toxic agents to eradicate thermo-resistant GBM cells at mild heat, as low as 41°C, with MHT and PTT both of clinical use. Indeed, a high U87 GBM cell mortality percentage is obtained only with dual MHT/PTT while each single treatment dose not provide the same cytotoxic effects. Only for the combined treatment, the cell death mechanism is assigned to clear sign of apoptosis as observed by structural/morphological cell studies and enhanced lysosome permeability.

Effect of plastic-free diet, education and Bisphenol A exposure feedback on urine BPA in adolescent

Abstract Background BPA is an endocrine disrupting chemical and is mostly taken orally. Adolescence is the critical sensitivity to these chemicals is maximum. This study was conducted to compare the effects of a plastic-free diet program, plastic-free diet education program and BPA exposure feedback on urine BPA levels in adolescents with high use of packaged products. Methods The first phase of the two-phase study is descriptive, the second phase is a single-centre, single-blind, three-arm non-randomized experimental design. The study was conducted at Antalya/Türkiye in the 2022-2023 academic year, and in the first stage, adolescents with high use of plastic packaged products and low attitudes towards healthy nutrition were identified. In the second stage, participants were assigned to the group-1 (n = 36), group-2 (n = 36) and group-3 (n = 36) by simple random sampling method. An eight-week plastic-free diet program was applied to the group 1, plastic-free diet education program and BPA exposure feedback was given to the group-2, and only BPA exposure feedback was given to the group-3. Plastic Packaged Product Usage Survey, Attitude Scale towards Healthy Nutrition, and spot urine samples were used to collect data. Results It was found that 2% of adolescents used low plastic packaging, 34% medium, 57% high, and 7% very high. Pre-posttest urine BPA levels ng/ml (µg/g creatinine) were 1.98 (2.54), 1.43 (1.51) in the intervention1 group, respectively; 1.91 (2.35), 1.43 (1.47) in the intervention2 group; It was found to be 1.97 (2.49) and 1.49 (1.66) in the intervention3 group. The effect sizes of pre-posttest BPA/creatinine values were calculated as 1.38, 1.13 and 1.09 in intervention1-2-3 groups, respectively. Conclusions All three interventions (plastic-free diet program, plastic-free diet education program and BPA exposure feedback) were effective in reducing urinary BPA levels, reducing plastic-packaged product use levels, and increasing attitudes towards healthy eating. Key messages • Since all three interventions are effective in reducing adolescents’ urinary BPA levels, it may be recommended to use the intervention appropriate to the field conditions. • In the post-tests, the use of plastic packaged products by adolescents in all three groups decreased and their attitudes towards healthy nutrition increased.

Drought field experiments: how to adapt rainout shelters to agroforestry?

AbstractAgroforestry could be a major strategy to adapt agriculture to climate change, thanks to the microclimate effects of trees and improved infiltration. However, the experimental validation of these claims is scarce. In this methodological review, we discuss options for the experimental simulation of drought conditions in agroforestry field experiments, comparing it with strategies adopted in natural, agricultural, or forestry ecosystems. We classify rainout shelters used in field experiments according to mobility, completeness of rain interception and height of rainout shelter. We show that specificities of agroforestry systems create constraints and require compromises in the design and operation of rainout shelters. We conclude that large rainout shelters, which induce drought for both the trees and the crops while limiting artifacts and biases, would be most relevant for studying the resistance of agroforestry systems to drought. Unfortunately, the review of rainout shelters already used in agroforestry systems reveals a lack of rainout shelters capable of intercepting rain on both trees and crops, achieving total rain interception, while being relatively low-cost and manageable by a small team. Therefore, we benchmark three novel rainout shelter designs that we tested in a mature agroforestry system under Mediterranean climatic conditions. We discuss their advantages and disadvantages in terms of both scientific and operational aspects. While compromises had to be done between experimental design, risks of artifact/bias, effectiveness, ease of installation, operation and maintenance, and agricultural management, these prototypes are starting points for achieving well-performing rainout shelters and testing the effects of drought in agroforestry experiments.

A self‐cooling self‐humidifying mosquito carrier backpack for transporting live adult mosquitoes on foot over long distances under challenging field conditions

AbstractIt is often necessary to use motorised transport to move live mosquitoes from distant field collection points into a central insectary, so that their behavioural and/or physiological phenotypes can be assessed under carefully controlled conditions. However, a survey of heritable insecticide susceptibility traits among wild‐caught Anopheles arabiensis mosquitoes, collected across an extensive study area composed largely of wilderness in southern Tanzania, necessitated that live mosquitoes were carried on foot over distances up to 25 km per day because most of the area was impassable by car, motorcycle or even bicycle during the rains. A self‐cooling, self‐humidifying carrier backpack was therefore developed that allows live adult mosquito specimens to be transported across rugged miombo woodland and floodplain terrain throughout the year. This wettable backpack was fabricated from stitched Tanzanian kitenge cotton fabric and polyvinyl chloride–coated fibreglass netting that allows easy circulation of air in and out. An outer cover flap made of cotton towelling embedded inside a kitenge envelope overhangs the fibreglass netting upper body of the bag, to protect mosquitoes from direct sunlight, and can be soaked with water to maintain low temperature and high humidity inside. Mean survival of insectary‐reared female An. arabiensis transported through nine different mobile camps inside the 509 km2 Ifakara‐Lupiro‐Mang'ula wildlife management area (ILUMA WMA), over up to 143 km and 25 days, was statistically indistinguishable from those left in the field insectary over the same period. Although considerable variance of survival was observed between different batches of mosquitoes from the insectary and between individual cups of mosquitoes, the different levels and positions inside the backpack had no influence on this outcome. Temperature and humidity inside the backpack were maintained at standard insectary conditions throughout, despite much more extreme conditions immediately outside. When the backpack was used to transport wild An. arabiensis and Anopheles quadriannulatus across a much larger study area of >4000 km2, encompassing the ILUMA WMA, some nearby villages and adjacent parts of Nyerere National Park (NNP), it achieved a mean survival rate of 58.2% (95% confidence interval 47.5–68.2). Encouragingly, no difference in survival was observed between ILUMA WMA and NNP even though transport back from NNP involves much longer distances, sometimes involving lengthy journeys by car or boat. Overall, this mosquito carrier backpack prototype appears to represent a viable and effective method for transporting live wild‐caught mosquitoes on foot across otherwise impassable terrain under challenging weather conditions with minimal detrimental impact on their survival.

Antifungal activity of citral against Fusarium wilt in tomatoes and induction of the upregulation of glucanase, chitinase, and thaumatin-like protein plant defense genes

Fusarium wilt of tomatoes, caused by the soil-borne fungus Fusarium oxysporum f. sp lycopersici (FOL), is one of the devastating diseases of tomatoes, causing substantial economic losses worldwide. It is primarily controlled with chemical fungicides. The present study assessed the antifungal activity of citral against FOL under greenhouse conditions and investigated its effects on three plant defense genes: glucanase, chitinase, and thaumatin-like protein (TLP) using Real-time- quantitative PCR (RT-qPCR). Greenhouse experiments demonstrated that citral oil at 1024 and 512 µg/mL significantly reduced wilt severity from 61.7 % to 28.3 and 33.3 %, respectively. RT-qPCR results revealed that citral upregulates the expression of the three defense genes to varying extents, highlighting their role in resistance induction in tomatoes against FOL. Chitinase showed the highest differential expression with a 9.54-fold increase at 12 hours post-treatment (hpt), followed by TLP with a 6.96-fold increase at 12hpt, and glucanase with a 3.68-fold increase at 24hpt. These findings suggest citral is a promising biocontrol agent against fusarium wilt in tomatoes. However, field trials are recommended to validate these results under open field conditions.

Short-term effects of co-applied biochar and paper mill biosolids on soil microbial communities under field conditions

Biochar and paper mill biosolids (PB) are reported to improve soil fertility, crop growth and indirectly conditions for soil microbial communities. However, it is unclear how the co-application of these materials impacts soil microbial communities under field conditions. A study was initiated in 2018 in Québec, QC, Canada and fine roots and rhizosphere soil were sampled to determine the effects of co-application of wood biochar (0, 10, and 20 Mg dry wt. ha−1) and PB (0 and 30 Mg wet wt. ha−1) on the percentage of corn (Zea mays L.) and soybean (Glycine max L. Merr.) root colonization by arbuscular mycorrhizal fungi (AMF), soil microbial biomass phosphorus (MBP) and microbial (Bacteria, Fungi and AMF) diversity and community structure in a temperate loamy soil. Co-applying PB and biochar increased soil MBP compared with the control and biochar-only application. Applying PB alone or with biochar increased the level of root colonization by AMF compared with the control and biochar-only application in soybean but not in corn. Overall, biochar and PB application had no significant effect on bacterial and AMF diversity and community structure compared with the control. However, applying PB alone or with biochar decreased the fungal alpha diversity (Shannon and Simpson indices), affected several fungal taxa abundances and shifted the fungal community structure as indicated by the principal coordination analysis (PCoA). Our results provided an understanding on the short-term effects of co-applied wood biochar and PB on microbial communities of a temperate loamy soil under field conditions, as well as scientific bases for further investigation.

Wearable Light Loggers in Field Conditions: Corneal Light Characteristics, User Compliance, and Acceptance

Understanding user challenges with light dosimeters is crucial for designing more acceptable devices and advancing light exposure research. We systematically evaluated the usability and acceptability of a light dosimeter (lido) with 29 participants who wore the dosimeter near the corneal plane of the eye for 5 days. Common reasons for not wearing the dosimeter included exercise, recharging, wet environments, public places, and discomfort. Despite these issues, participants adhered to using the dosimeter with high compliance (89% of recording time). Our findings revealed a significant discrepancy between mean (300 lxmEDI) and median (51 lxmEDI) melanopic equivalent daylight illuminance. This discrepancy indicates that the participants were exposed to significantly lower light levels most of the time. Specifically, participants were exposed to light levels above 250 lxmEDI for only 14% of their wearing time. This highlights the need for increased exposure to recommended light levels. In the evening, participants were exposed to less than the recommended 10 lxmEDI for 58% of their wearing time, which is in line with the guidelines for reducing light exposure before sleep. This study highlights the urgent need for strategies to increase daily light exposure that are more in line with circadian health recommendations.

Generation of Circularly Polarized Strong-Field Terahertz Waves

Abstract Terahertz (THz) circular dichroism (TCD) spectroscopy has been widely used to study the chiral characteristics of biological macromolecules and various other materials. With the rapid development of strong-field THz generation and field-modulated techniques, the advancement of tunable strong-field TCD spectroscopy technology is of great significance. In this work, we built an integrated strong-field TCD spectroscopy system. We employed the tilted-pulse-front technique to generate linearly polarized strong-field THz radiation and a reflective metasurface for linear-to-circular conversion of the strong-field THz radiation. We obtained circularly polarized THz radiation with an ellipticity of over 0.9 in the frequency range from 0.38 THz to 0.61 THz, with a LTC conversion efficiency of over 90%. The peak electric field strength of the obtained strong-field circularly polarized THz radiation exceeded 100 kV/cm. This system is expected to be used to study the chiral characteristics of materials under strong-field conditions, as well as changes in the chiral characteristics under different field conditions.

Development and Validation of Asphalt Pavement Rutting Prediction Model with Transient Temperature Field Considered

This study developed a transient rutting analysis program based on the principles of heat transfer and the viscoelastic–viscoplastic theory of asphalt mixtures. Using the finite element model (FEM) model corresponding to the multi-layer pavement structure and the subprogram interface of ABAQUS software, along with Python programming, the program was designed to estimate rutting under transient temperature field conditions with climate conditions, traffic flow, and structure layer constitutive parameters of pavement considered. Subsequently, the program was used to validate the efficiency of the solution and analyze the influencing factors of internal temperature field and rutting depth within the asphalt pavement structure. Results showed that, based on meteorological data and recommended values of material thermal properties, the FEM of transient temperature field can accurately simulate the temperature field distribution of pavement structure. Based on loading information and dynamic modulus test, the transient temperature variable rutting with FEM proposed in this paper can simulate and calculate the rutting of pavement structure layer with some errors for different pavement conditions from 5% to 40%. Through parametric analysis of the influence factors of temperature field and rutting, the modified transient temperature field rutting prediction program can effectively simulate rutting of pavement structure, and the minor errors were less than 20%.

Study on wind load characteristics of gable roof under tornado

This research simulates the behavior of a tornado on a double-slope roof using the Ward tornado generator and the \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SS{T_{k - \\omega }}$$\\end{document} turbulence model. The effects of different ground roughness, slope angle, and wind field position on the tornado load characteristics of gable roofs were studied. The tornado-generating device established the tornado field under various working conditions, and the simulation results were compared with the experimental data to verify the reliability of the simulation results. The wind pressure distribution of gable roofs with four different slope angles was analyzed to find the most unfavorable roof condition of the tornado field. The gable roof’s aerodynamic and wind pressure characteristics at various places in the tornado field were explored by comparing the wind pressure coefficients at five distinct positions on smooth and rough ground. The lift-drag and wind pressure coefficients of five kinds of ground roughness were calculated to determine the influence of different ground roughness on the aerodynamic force and partial pressure distribution of the gable roof. The ground roughness reduces the vortex ratio because the ground roughness reduces the maximum tangential wind speed and the radius of the vortex core. Therefore, the gable roof’s suction increases as the updraft increases.

Isolation and identification of native Chilean entomopathogenic fungi and their potential for the control of Drosophila suzukii

Drosophila suzukii is an invasive pest of berries and other soft-skinned fruits, was first detected in Chile in 2017, and has since spread over 2,800 km from north to south. Sustainable control of the spotted-wing drosophila (SWD) is essential due the negative attitude of the consumers toward the excessive use of insecticides. During a survey in Chile for biological control agents, thirty-two isolates of entomopathogenic fungi (EPF) were isolated from mycotized insects and soil samples, identified through sequence analysis, and tested against D. suzukii adults under laboratory conditions. The EPF identified are Akanthomyces muscarius, Beauveria bassiana, Beauveria pseudobassiana, Clonostachys rosea, Metarhizium alvesii, Metarhizium brunneum and Metarhizium robertsii. Six isolates caused 100 % of mortality of D. suzukii adults within ten days after the initial exposition to conidia; these included four B. bassiana isolates (LSB 110, LSB 114, LSB 122 and LSB 125), one M. robertsii isolate (LSB 115) and one M. brunneum isolate (LSB 127). LSB 122 and LSB 125 induced the shortest lethal time (LT50 4 and 4.2 days, respectively), while Akanthomyces and Clonostachys caused ≤36 % cumulative mortality of the adults at 10 days of exposure. These results indicate that isolates of B. bassiana, M. robertsii and M. brunneum have significant potential as microbial control agents against D. suzukii adults. This study marks a critical step forward in identifying and validating native entomopathogenic fungi in Chile for sustainable pest management. Future work will focus on further testing these isolates under laboratory, semi-field and field conditions to optimize their application in real-world agricultural settings.