Generation Time Research Articles

The Flight Pattern of Navel Orangeworm (Amyelois transitella Walker) 2008–2023 in California Pistachio

The navel orangeworm, Amyelois transitella, is the principal pest of pistachio and almond in California. The timing of the insecticide application is challenging because there is no model that predicts when pistachio is vulnerable to infestation. Sixteen years of pistachio flight data from Madera and Fresno counties (541,892 adults) were analyzed to determine if there was a consistent starting point each year for flights that overlap pistachio vulnerability. This effort was complicated by changes in trap lures over this period, as unmated females were replaced by a combination lure consisting of the synthetic pheromone and phenyl propionate, which is needed because mating disruption suppresses pheromone lure trap capture. There were two additional complications: the increased degree day accumulation during the growing season and the three-fold hectarage expansion of pistachio. A biofix at 944.4 degree days °C from the beginning of the year was identified from the dataset, which was consistent across all years in both counties. Using the biofix, subsequent flight peaks occurred at 277.78 degree day °C intervals (generation time on new crop pistachios), corresponding to three weeks in the field. This biofix can be used to improve the timing of field scouting, which in turn will improve the timing of insecticide application.

Developing a method to generate an adaptive real-time camouflage pattern based on electro-chromic active devices

Traditional camouflage faces limitations in modern combat, especially with moving targets or rapidly changing backgrounds. Adaptive camouflage, which adjusts colors and patterns in real time, provides a more flexible and effective solution. This paper presents a comprehensive study of popular adaptive camouflage principles worldwide and proposes a camouflage model for the visible light spectrum based on active electro-chromic principles. Evaluation results indicate that adaptive patterns achieve the lowest Camouflage Similarity Index (CSI) and the highest Universal Image Quality Index (UIQI) across various backgrounds, demonstrating the clear effectiveness of the proposed model. With 3 to 5 dominant colors, pattern generation time is under 1 second, and adaptive patterns exhibit the highest similarity to the background compared to fixed patterns.

An innovative natural speed breeding technique for accelerated chickpea (Cicer arietinum L.) generation turnover

BackgroundThe slow breeding cycle presents a significant challenge in legume research and breeding. While current speed breeding (SB) methods promise faster plant turnover, they encounter space limitations and high costs. Enclosed environments risk pest and disease outbreaks, and supplying water and electricity remains challenging in many developing nations. Here, we propose an innovative natural speed breeding (nSB) approach to achieve two generation cycles per rabi season under natural open field conditions in chickpea. This cost-effective, environmentally friendly method offers a location-specific alternative to prevalent SB techniques.ResultsTwo field experiments were conducted. First, 11-day-old fresh immature green (FIG) seeds exhibited an 80% germination rate, reducing the duration of the breeding cycle by 14%. In second, abiotic stresses such as atmospheric, nutrient, soil, and water stresses reduced the duration of the breeding cycle by 40%, 18%, 15%, and 18%, respectively. Despite the shortened generation time, we consistently obtained a minimum of 4–6 pods plant-1, ensuring continuity in the subsequent breeding cycle without compromising the nSB process.ConclusionOur investigation revealed that the combination of this location advantage (40%) with the sowing of FIG seeds (14%) enables Baramati to achieve progress from F2 to F5 in 1.5 years, with two generation cycles per rabi (cool) season. Using the nSB method can save 3 years, marking a notable reduction from the conventional six-year timeline. Moreover, incorporating the additional abiotic stresses mentioned above will further reduce the generation advancement time. Therefore, nSB accelerates generation turnover and reduces varietal improvement time at a low cost.

A polynomial proxy model approach to verifiable decentralized federated learning

Decentralized Federated Learning improves data privacy and eliminates single points of failure by removing reliance on centralized storage and model aggregation in distributed computing systems. Ensuring the integrity of computations during local model training is a significant challenge, especially before sharing gradient updates from each local client. Current methods for ensuring computation integrity often involve patching local models to implement cryptographic techniques, such as Zero-Knowledge Proofs. However, this approach becomes highly complex and sometimes impractical for large-scale models that use techniques such as random dropouts to improve training convergence. These random dropouts create non-deterministic behavior, making it challenging to verify model updates under deterministic protocols. We propose ProxyZKP, a novel framework combining Zero-Knowledge Proofs with polynomial proxy models to provide computation integrity in local training to address this issue. Each local node combines a private model for online deep learning applications and a proxy model that mediates decentralized model training by exchanging gradient updates. The multivariate polynomial nature of proxy models facilitates the application of Zero-Knowledge Proofs. These proofs verify the computation integrity of updates from each node without disclosing private data. Experimental results indicate that ProxyZKP significantly reduces computational load. Specifically, ProxyZKP achieves proof generation times that are 30–50% faster compared to established methods like zk-SNARKs and Bulletproofs. This improvement is largely due to the high parallelization potential of the univariate polynomial decomposition approach. Additionally, integrating Differential Privacy into the ProxyZKP framework reduces the risk of Gradient Inversion attacks by adding calibrated noise to the gradients, while maintaining competitive model accuracy. The results demonstrate that ProxyZKP is a scalable and efficient solution for ensuring training integrity in decentralized federated learning environments, particularly in scenarios with frequent model updates and the need for strong model scalability.

Novel Energy-Aware 3D UAV Path Planning and Collision Avoidance Using Receding Horizon and Optimization-Based Control

Unmanned Aerial Vehicles (UAVs) have gained significant popularity in recent years thanks to their agility, mobility, and cost-effectiveness. However, UAV navigation presents several challenges, particularly in path planning, which requires determining an optimal route while avoiding obstacles and adhering to various constraints. Another critical challenge is the limited flight time imposed by the onboard battery. This paper introduces a novel approach for energy-efficient three-dimensional online path planning for UAV formations operating in complex environments. We formulate the path planning problem as a minimization optimization problem, and employ Mixed-Integer Linear Programming (MILP) to achieve optimal solutions. The cost function is designed to minimize energy consumption while considering the inter-collision and intra-collision avoidance constraints within a limited detection range. To achieve this, an optimization approach incorporating Receding Horizon Control (RHC) is applied. The entire path is divided into segments or sub-paths, with constraints used to avoid collisions with obstacles and other members of the fleet. The proposed optimization approach enables fast navigation through dense environments and ensures a collision-free path for all UAVs. A path-smoothing strategy is proposed to further reduce energy consumption caused by sharp turns. The results demonstrate the effectiveness and accuracy of the proposed approach in dense environments with high risk of collision. We compared our proposed approach against recent works, and the results illustrate that the proposed approach outperforms others in terms of UAV formation, number of collisions, and partial path generation time.

Isolation and characterization of DNA aptamers against the HlyE antigen of Salmonella Typhi

Aptamers have emerged as prominent ligands in clinical diagnostics because they provide various advantages over antibodies, such as quicker generation time, reduced manufacturing costs, minimal batch-to-batch variability, greater modifiability, and improved thermal stability. In the present study, we isolated and characterized DNA aptamers that can specifically bind to the hemolysin E (HlyE) antigen of Salmonella Typhi for future development of typhoid diagnostic tests. The DNA aptamers against Salmonella Typhi HlyE were isolated using systematic evolution of ligands by exponential enrichment (SELEX), and their binding affinity and specificity were assessed utilizing enzyme-linked oligonucleotide assay (ELONA). A total of 11 distinct aptamers were identified, and the binding affinities and species selectivities of the three most probable aptamers were determined. Kd values were obtained in the nanomolar range, with the highest affinity of 83.6 nM determined for AptHlyE97. In addition, AptHlyE11, AptHlyE45 and AptHlyE97 clearly distinguished S. Typhi HlyE from other tested bacteria, such as Salmonella Paratyphi A, Salmonella Paratyphi B, Shigella flexneri, Klebsiella pneumonia and Escherichia coli, therefore displaying desirable specificity. These novel aptamers could be used as diagnostic ligands for the future development of inexpensive and effective point-of-care tests for typhoid surveillance, especially in developing countries of the tropics and subtropics.

Efficient Zero-Knowledge Proofs for Set Membership in Blockchain-Based Sensor Networks: A Novel OR-Aggregation Approach

Blockchain-based sensor networks offer promising solutions for secure and transparent data management in IoT ecosystems. However, efficient set membership proofs remain a critical challenge, particularly in resource-constrained environments. This paper introduces a novel OR-aggregation approach (where “OR” refers to proving that an element equals at least one member of a set without revealing which one) for zero-knowledge set membership proofs, tailored specifically for blockchain-based sensor networks. We provide a comprehensive theoretical foundation, detailed protocol specification, and rigorous security analysis. Our implementation incorporates optimization techniques for resource-constrained devices and strategies for integration with prominent blockchain platforms. Extensive experimental evaluation demonstrates the superiority of our approach over existing methods, particularly for large-scale deployments. Results show significant improvements in proof size, generation time, and verification efficiency. The proposed OR-aggregation technique offers a scalable and privacy-preserving solution for set membership verification in blockchain-based IoT applications, addressing key limitations of current approaches. Our work contributes to the advancement of efficient and secure data management in large-scale sensor networks, paving the way for wider adoption of blockchain technology in IoT ecosystems.

Geology of Mudstones Atop the Sangonghe Formation, Shuixigou Group, Turpan‐Hami Basin: New Insights and Their Implications for Petroleum Geology

ABSTRACTAs the exploration of deep‐seated oil and gas resources in the Turpan‐Hami Basin intensifies, there is an urgent need to thoroughly depict the geological characteristics of newly uncovered, underexplored strata in sub‐sag centers. This study undertakes the inaugural systematic geochemical analysis of mudstones atop the Sangonghe Formation, including palynological identification, maceral identification, biomarker analysis, total organic carbon (TOC) analysis, and pyrolysis. The findings reveal that the mudstone sequence, as the target layer, was deposited in a warm and moist paleoclimate and a weakly reducing to weakly oxidising saline water environment, fostering the growth of prolific algae and bacteria, thus ensuring substantial foundational materials for source rock formation. The organic matter in the mudstone sequence displays pronounced laminar accumulation. Despite the overall modest abundance, the organic matter features notable hydrocarbon‐generating potential per unit of organic carbon and favourable types. Humic‐sapropelic kerogens (type II1) are found in the mudstones, with organic matter generally reaching a mature to highly mature stage. These characteristics establish the mudstones as effective source rocks, furthermore, the hydrocarbon expulsion in the Xishanyao Formation precedes that of the Sangonghe Formation and that both formations constitute a sequential process in terms of hydrocarbon generation and expulsion timing and hydrocarbon contribution. Reanalyzing this mudstone sequence not only revises prior geological understanding of it as direct cap rocks, but also facilitates the reclassification of deep‐seated strata into three distinct petroleum systems. Centered around this source rock layer, dual modes, namely the “lower‐source rock and upper‐reservoir” and the “ lower‐reservoir and upper‐source rock” modes can be formed. These new insights will offer profound implications for hydrocarbon resource evaluation and future hydrocarbon exploration endeavours in the Shuixigou Group within the Taibei sag.

Rapid colonization of a space‐returned Ryugu sample by terrestrial microorganisms

AbstractThe presence of microorganisms within meteorites has been used as evidence for extraterrestrial life, however, the potential for terrestrial contamination makes their interpretation highly controversial. Here, we report the discovery of rods and filaments of organic matter, which are interpreted as filamentous microorganisms, on a space‐returned sample from 162173 Ryugu recovered by the Hayabusa 2 mission. The observed carbonaceous filaments have sizes and morphologies consistent with microorganisms and are spatially associated with indigenous organic matter. The abundance of filaments changed with time and suggests the growth and decline of a prokaryote population with a generation time of 5.2 days. The population statistics indicate an extant microbial community originating through terrestrial contamination. The discovery emphasizes that terrestrial biota can rapidly colonize extraterrestrial specimens even given contamination control precautions. The colonization of a space‐returned sample emphasizes that extraterrestrial organic matter can provide a suitable source of metabolic energy for heterotrophic organisms on Earth and other planets.

TMOD-20. RAPID PROCESSING AND BIOBANKING OF RESECTED BRAIN TUMOR TISSUE TO GENERATE PATIENT-DERIVED BRAIN TUMOR EXPLANT ORGANOIDS (GBOS) FOR PRECLINICAL STUDIES

Abstract Improved preclinical tools are urgently needed to translate new brain cancer treatments. Patient-derived brain tumor explant organoids (GBOs) offer promise for studying tumor cells in a relevant human tumor microenvironment and predicting patient responses to therapy. However, generating GBOs is time-consuming, costly, and technically challenging, hindering the creation of comprehensive biobanks covering the spectrum of brain tumor heterogeneity. This work presents a semi-automated method for producing GBOs, involving tumor tissue processing, size selection, and same-day cryopreservation, reducing generation time to less than 1 hour. We established a biobank of 24 GBOs from 33 samples (11 males and 13 females) with primary (n=13, GBO Yield (GY)>90%) and recurrent (n=5, GY>90%) glioblastomas, high-grade gliomas (HGG, n=2, GY≤50%), and low-grade gliomas (LGG, n=2 with GY>90%, n=2 with GY≤50%). Using GBO size and propidium iodide as readouts, we used this biobank to compare anticancer activities of novel idronoxil-conjugated benzopyran compounds (NX786, NX904/904E1) against Bortezomib (100% cell death reference). NX786 and NX904/904E1 reduced GBO growth (≥50%) in all primary glioblastoma and one (of two) recurrent glioblastoma GBOs with milder effects in LGG GBOs. Two (of four) primary glioblastoma, one (of two) recurrent glioblastoma, and one LGG GBOs exhibited significant cell death (>60%) in response to NX904/904E1. In contrast, NX786 induced cell death in one (of three) primary glioblastoma (34% cell death) and one (of two) recurrent glioblastoma (71% cell death) GBOs but not in LGG GBOs, together showcasing varied responses across different brain tumors. Highly-passaged GBOs lacking the non-malignant tumor microenvironment were more susceptible to these treatments, underlining the tumor microenvironment’s critical role in responses to anticancer agents. We provide a new method for efficient processing and cryopreserving GBOs, enabling the establishment of large biobanks for patient-specific preclinical drug testing across brain tumor subgroups in a clinically relevant human 3D model.

A biomimetic approach towards a universal slippery liquid infused surface coating.

One biomimetic approach to surface passivation involves a series of surface coatings based on the slick surfaces of carnivorous pitcher plants (Nepenthes), termed slippery liquid-infused porous surfaces (SLIPS). This study introduces a simplified method to produce SLIPS using a polydopamine (PDA) anchor layer, inspired by mussel adhesion. SLIPS layers were formed on cyclic olefin copolymer, silicon, and stainless steel substrates, by first growing a PDA film on each substrate. This was followed by a hydrophobic liquid anchor layer created by functionalizing the PDA film with a fluorinated thiol. Finally, perfluorodecalin was applied to the surface immediately prior to use. These biomimetic surface functionalization steps were confirmed by several complimentary surface analysis techniques. The wettability of each surface was probed with water contact angle measurements, while the chemical composition of the layer was determined by X-ray photoelectron spectroscopy. Finally, ordering of specific chemical groups within our PDA SLIPS layer was determined via sum frequency generation spectroscopy. The hemocompatibility of our new PDA-based SLIPS coating was then evaluated by tracking FXII activation, fibrin generation time, clot morphology, and platelet adhesion to the surface. This hemocompatibility work suggests that PDA SLIPS coatings slow or prevent clotting, but the observation of both FXII activation and the presence of adherent and activated platelets at the PDA SLIPS samples imply that this formulation of a SLIPS coating is not completely omniphobic.

Implications of temperature-dependent development and survival of Hemipteroseius adleri Costa, 1968 on its distribution in central Europe

Otopheidomenidae include 30 species of parasites of insects. These mites occur in areas with warm and hot climates. The only exception is Hemipteroseius adleri, the distribution of which reaches the central European region, which is characterised by a moderate climate with below-zero temperatures in winter. In Europe, H. adleri only parasitises the red firebug (Pyrrhocoris apterus). Field observations indicate that only fertilised females of H. adleri survive winter conditions. The aim of the study therefore was to evaluate the impact of air temperature on the development and survival of H. adleri. A research model was established involving mites parasitising red firebugs in laboratory conditions at 15, 20, 25 and 30 °C. After oviposition, no egg development was possible at 15 °C. Egg development began at 20 °C, however the egg-to-adult period lasted for 13 days and larval mortality was significantly higher at this temperature than at 25 and 30 °C. At the latter tem temperatures, mites matured fastest (five and four days, respectively). The net reproductive rate (R0) was 10.8, the mean generation time was (T) 14.4 (SD = 0.273), the intrinsic rate of population increase (rm) was 0.165 (SD = 0.003), and the finite rate of population increase (λ) was 1.12. At 25 °C, H. adleri required 4.2 days to double its population. The results indicate that the thermal conditions prevailing in early spring in central Europe are highly unfavourable for the effective reproduction of H. adleri. The presence of northern populations of this mite is discussed in the context of behavioural thermoregulation mechanisms adapted by its host, P. apterus.

Understanding energy fluctuation during the transition state: The role of AbrB in Bacillus licheniformis

BackgroundLimited research has been conducted on energy fluctuation during the transition state, despite the critical role of energy supply in microbial physiological metabolism.ResultsThis study aimed to investigate the regulatory function of transition state transcription factor AbrB on energy metabolism in Bacillus licheniformis WX-02. Firstly, the deletion of abrB was found to prolong the cell generation time, significantly reducing the intercellular ATP concentration and NADH/NAD+ ratio at the early stage. Subsequently, various target genes and transcription factors regulated by AbrB were identified through in vitro verification assays. Specifically, AbrB was shown to modulate energy metabolism by directly regulating the expression of genes pyk and pgk in substrate-level phosphorylation, as well as genes narK and narGHIJ associated with nitrate respiration. In terms of oxidative phosphorylation, AbrB not only directly regulated ATP generation genes, including cyd, atpB, hmp, ndh, qoxA and sdhC, but also influenced the expression of NAD-dependent enzymes and intracellular NADH/NAD+ ratio. Additionally, AbrB positively affected the expression of transcription factors CcpN, Fnr, Rex, and ResD involved in energy supply, while negatively affected the regulator CcpA. Overall, this study found that AbrB positively regulates both substrate-level phosphorylation and oxidative phosphorylation, while negatively regulating nitrate respiration.ConclusionsThis study proposes a comprehensive regulatory network of AbrB on energy metabolism in Bacillus, expanding the understanding of regulatory mechanisms of AbrB and elucidating energy fluctuations during the transition state.

Comparative demography of two wild cladoceran species, Alona quadrangularis and Scapholeberis mucronata, collected in western Washington state and reared under laboratory conditions

AbstractPopulations of two cladoceran species, Alona quadrangularis and Scapholeberis mucronata, were collected from a pond in Puyallup, Washington, and reared under controlled laboratory conditions. Life tables were developed for each species under the same environmental conditions and feeding regimen to develop basic demographic data. We also compared the major demographic parameters of these two wild species with those of several cladoceran species that are commonly used in laboratory research, Daphnia pulex, D. magna, and Ceriodaphnia dubia. Compared to A. quadrangularis, S. mucronata had a much higher net reproductive rate (R0), a longer generation time (T), but a similar intrinsic rate of increase (rm), similar finite rate of increase, similar doubling time (DT), and a lower birth rate (b). Both wild species had lower R0, shorter T, and higher b than in D. pulex, D. magna, and C. dubia. Results of this study showed that demographic rates differed between A. quadrangularis and S. mucronata, and differed from those reported for the other three laboratory species. These results suggest that data developed for commonly used cladoceran species in the laboratory should not be used to make generalizations about effects on wild species.

Applications of CRISPR Technologies in Forestry and Molecular Wood Biotechnology.

Forests worldwide are under increasing pressure from climate change and emerging diseases, threatening their vital ecological and economic roles. Traditional breeding approaches, while valuable, are inherently slow and limited by the long generation times and existing genetic variation of trees. CRISPR technologies offer a transformative solution, enabling precise and efficient genome editing to accelerate the development of climate-resilient and productive forests. This review provides a comprehensive overview of CRISPR applications in forestry, exploring its potential for enhancing disease resistance, improving abiotic stress tolerance, modifying wood properties, and accelerating growth. We discuss the mechanisms and applications of various CRISPR systems, including base editing, prime editing, and multiplexing strategies. Additionally, we highlight recent advances in overcoming key challenges such as reagent delivery and plant regeneration, which are crucial for successful implementation of CRISPR in trees. We also delve into the potential and ethical considerations of using CRISPR gene drive for population-level genetic alterations, as well as the importance of genetic containment strategies for mitigating risks. This review emphasizes the need for continued research, technological advancements, extensive long-term field trials, public engagement, and responsible innovation to fully harness the power of CRISPR for shaping a sustainable future for forests.

Biological performance of Bollgard II® Bt-resistant vs susceptible population of pink bollworm, Pectinophora gossypiella (Saunders) on non-toxic diet

BackgroundThe pink bollworm, Pectinophora gossypiella (Saunders), is a devastating global pest of cotton that has caused substantial economic damage to Bt Bollgard-II® cotton plants in recent years due to the evolution of Bt resistance. The associated fitness cost is assumed to be one of the factors delaying the development of resistance against Bt transgenic crops. Hence, the present study was undertaken to assess the biological performance of pink bollworms by comparing the life history and demographic parameters of a resistant (Field-R) and susceptible (Lab-S) population.ResultsProlonged larval duration (23.40 days in Field-R vs 18.80 days in Lab-S population), total life cycle (male = 50.00 vs 42.80 days; female = 53.60 vs 46.20 days), reduced fecundity (100.60 vs 154.20 eggs/female) and fertility (88.00 vs 138.00 fertile eggs/female) was observed. The demographic parameters indicated a significant reduction in the net reproductive rate (184.27 vs 276.72), innate capacity for increase in number (0.11 vs 0.15), finite rate of increase in number (1.12 vs 1.16 female progenies produced/female/day), weekly multiplication rate (2.16 vs 2.86), potential fecundity (545.06 vs 634.11 eggs), number of hypothetical F2 females (33 955.65 vs 76 572.41), but longer mean length of generation (47.54 vs 37.74 days) and population doubling time (6.30 vs 4.62 days) in Field-R compared with Lab-S population. A stage-specific life table demonstrated the differences in survival rates between susceptible and resistant populations at various life stages, with the resistant population having higher generation mortality (0.22 vs 0.19).ConclusionsThe study confirms the involvement of fitness costs associated with Bt resistance in P. gossypiella. Despite reduced reproductive fitness, the resistant population tried prolonging the larval stage as a compensatory mechanism to repair the damaged host tissues due to Bt intoxication and for accumulation of enough nutrient reserves for normal pupation and adult emergence. Presence of a high proportion of double Bt-resistant larvae in the field coupled with continued noncompliance with refug planting certainly favours the flaring up of this monophagous pest despite the observed fitness costs. The resistance cannot be effectively reversed unless suitable alternative management strategies are deployed.

Fitness Costs in Diamondback Moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) Resistant to Lufenuron, A Chitin-Synthesis Inhibitor Insecticide.

The diamondback moth (DBM), Plutella xylostella, is the main pest of Brassicas crops worldwide, and its recorded resistance to 101 active ingredients indicates it is difficult to control. The purpose of this study was to investigate the hypothesis that P. xylostella has fitness costs associated with its resistance to lufenuron, a chitin-synthesis inhibitor insecticide. Thus, concentration-mortality bioassays were performed for susceptible (REC-S), resistant (BZR-R) populations, their progenies F1 and F1', and one established population without selection pressure (BZR-Rns) after four generations. A fertility life table was used to assess the biological performance of the REC-S and BZR-R. BZR-Rns of P. xylostella. The larval stage, longevity, and survival differed between populations. The reproductive rate (R0) was significantly lower in the F1 (♀R × ♂S) (28.19) and F1' (♀S × ♂R) (34.06) progenies compared with their parents, but not with the relaxed BZR-Rns (39.39). The mean generation time (T), intrinsic rate of population growth (rm), and doubling time (DT) differed between REC-S and progenies, with fitness of 0.52 and 0.64 for F1 and F1', respectively. Overall, the results suggest that the resistance of P. xylostella to lufenuron is stable and that low fitness costs appear to be associated with resistance to lufenuron, although heterozygotes showed lower fitness than their parents. Strategies such as preserving refuge areas, rotation of modes of action, etc., are essential for resistance management and prolonging the efficacy of control agents; this highlights the importance of integrated insecticide resistance management.

Numerical simulation of jet interaction flow field of complex configuration based on hybrid grid method

Abstract The supersonic/hypersonic jet interaction flow field includes many fluid phenomena such as shock waves, separation and reattachment of the boundary layer, expansion wave, Mach disk, shear layer, and so on. The complexity of the jet interaction flow field makes it difficult to simulate accurately, and the structured grid method is generally used in engineering applications. However, the structured grid has many shortcomings when dealing with complex configurations, and the traditional hybrid grid method has the problem of insufficient accuracy. In the paper, a structured/unstructured grid algorithmic coupling numerical simulation method is developed. Firstly, the feasibility and accuracy of this method are verified by numerical simulation of the jet interference flow field of cone-cylinder-skirt shape, along with a comparison with the results of the experiment and structural method. Then, the jet interference flow fields of the rudders and the grid fins configuration are simulated to show the efficiency of the method, and the accuracy is further verified. The results show that the hybrid numerical simulation method can save grid generation time and grid quantity to a certain extent when compared with the structural, showing higher accuracy, which provides an accurate and efficient solution to jet interaction problems with complex configurations.

Life table and feeding behavior of Myzus persicae (Hemiptera: Aphididae) at sublethal concentrations of Afidopyropen, Spirotetramat and sulfoxaflor

AbstractThe green peach aphid Myzus persicae Sülzer is a major insect pest of cruciferous plants, including vegetables such as Chinese cabbage. The objective of the present study was to determine the effects of sublethal afidopyropen and spirotetramat concentrations on the survival and reproduction of M. persicae. In addition, we used an electrical penetration graph (EPG) to study the feeding behavior of M. persicae on Chinese cabbage leaves treated with various concentrations of afidopyropen, spirotetramat and sulfoxaflor. The results showed that sublethal concentrations (LC10 and LC30) of afidopyropen and spirotetramat significantly decreased adult longevity and fecundity. However, sulfoxaflor had no significant effects. Several population parameters, including the net reproductive rate (R0), intrinsic rate of increase (rm), mean generation time (T), finite rate of increase (λ), and doubling time (DT), were significantly decreased only at the LC30 of spirotetramat. According to the EPG feeding behavior analyses, when all three insecticides were applied at LC30, the nonpenetration (NP) waveform significantly increased. The above results can be used as basic data for the well‐planned use of insecticides.

Reduced canopy cover and development compromises weed suppression by buckwheat in cover crop mixtures

Buckwheat (Fagopyrum esculentum Moench) is a common cover crop typically grown for its rapid establishment and superior weed suppression. One challenge of incorporating buckwheat into crop rotations, however, is its short generation time, which requires in-season management to prevent viable seed production and volunteers in subsequent crops. Mixing buckwheat at reduced seeding rates with other cover crop species is one way for producers to reduce volunteer potential; however, this may compromise weed suppression. To investigate mechanisms behind buckwheat weed suppression and how using buckwheat in mixtures can affect suppression, we collected a series of morphological measurements in buckwheat monocultures and in three, two-way and four, three-way cover crop species mixtures and modeled their response over the growing season. We found that while buckwheat height and relative growth rate were unaffected with increasing species richness, there was a significant reduction in maximum leaf area index (3.75 vs. 2.85 vs. 2.82 cm2 cm-2) in mixture. Buckwheat monocultures provided superior season-long weed suppression compared to mixtures (85% vs. 53% vs. 50%). Principal component analysis showed that increased height and leaf area index values were associated with greater weed suppression. The link between reduced leaf area index and weed suppression in mixtures compared to buckwheat monocultures suggests that the rapid leaf development and canopy cover associated with buckwheat is a key mechanism behind weed suppression. In practice, producers should expect a dilution effect and weed suppression to be compromised when the buckwheat seeding rate is reduced in mixtures.