Computer, Engineering and Natural Sciences: Recent submissions
Now showing items 1-20 of 940
-
Acceptability and suitability of some Poaceae plants for fall armyworm feeding and ovipositionBackground: The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), has invaded new geographical regions, now spanning Africa, Asia, Oceania and Europe, from its native distribution in the last decade. Little is known about FAW host plants in recently invaded habitats; although more than 300 hosts have been reported in the Americas, its native habitat. In our study, we evaluated the acceptability and suitability of 12 cultivated varieties of plants from Africa, in the family Poaceae, for FAW herbivory and oviposition. Methods: Experiments investigating larval development, no-choice oviposition, and no-choice larval arrestment-feeding were conducted to evaluate the insect´s ability to utilize these plants for survival. Results: We found that Pennisetum ex. Sengerema, Brachiaria brizantha , Brachiaria ex. Mwanza, Panicum maximum ex. Machakos, Melinis minutiflora and S . bicolor cv. Ochuti were unsuitable plants for FAW larvae. In contrast, Zea mays HB WH505, Panicum glaucum Nutrifeed, S . bicolor cv. Serena and P . purpureum were suitable plants and S . bicolor cv. Ochuti was well accepted for egg-laying. However, M . minutiflora was not accepted for egg-laying but retained early instar larvae. S . bicolor cv. Andiwo was not well accepted for egg-laying and S . bicolor cv. Gadam yielded lighter pupae. Conclusions: Our findings provide insights into the performance of FAW larvae on different Poaceae plants and how well they are accepted by FAW female moths for oviposition. We recommend to study further selected plants ( M . minutiflora , S . bicolor cv. Andiwo and S . bicolor cv. Ochuti), as potential trap or repellent plants for different FAW life stages, in choice tests. This knowledge will help to design ecologically based management strategies for FAW in its new habitats in Kenya and beyond.
-
Third-order time stepping methods for superdiffusion using weighted and shifted Grünwald–Letnikov formulae with nonsmooth dataIn this paper, we study a numerical method for the Caputo time fractional wave equation with nonsmooth data. We first introduce a class of third-order approximations, known as weighted and shifted Grünwald-Letnikov approximations, to approximate the Caputo fractional derivative. Based on this, we develop a new time stepping method for solving the time fractional wave equation. After applying corrections to several initial steps, the proposed time stepping method achieves a convergence order of O(k3)$$O(k^3)$$ for nonsmooth data, where k denotes the time step size. We also analyze the stability regions of the proposed time stepping method, which show that the scheme is unconditionally stable for α∈(1,1.94)$$ \alpha \in (1, 1.94) $$, and conditionally stable for α∈[1.94,2)$$ \alpha \in [1.94, 2) $$. Numerical experiments are presented to validate the theoretical findings.
-
Time discretization schemes for stochastic subdiffusion and fractional wave equations with integrated additive noiseIn this paper, we introduce a time discretization scheme for solving the stochastic subdiffusion equation based on the two-fold integral-differential and two step backward differentiation formula (ID2-BDF2). We prove that this scheme attains a convergence rate of O ( τ α + γ − 1 / 2 ) for 1 / 2 < α + γ < 2 with α ∈ (0, 1) and γ ∈ [0, 1]. Our approach regularizes the additive noise through a two-fold integral-differential (ID2) calculus and discretizes the equation using BDF2 convolution quadrature, achieving superlinear convergence in solving the stochastic subdiffusion. Furthermore, we extend the scheme to solve the stochastic fractional wave equation, proving that the scheme achieves a convergence rate of O ( τ min { 2 , α + γ − 1 / 2 } ) for α ∈ (1, 2) and γ ∈ [0, 1]. Numerical examples are presented to validate the theoretical results for the linear problem. The numerical observations further indicate that the same convergence rates also apply to stochastic semilinear time-fractional equations.
-
An efficient reduced-order approximation for the stochastic Allen-Cahn equationIn this paper, we propose and analyze an efficient numerical method for solving the stochastic Allen-Cahn equation with additive noise. The method combines a stabilized semi-implicit time discretization scheme with a reduced-order finite element spatial discretization method. The core idea is to approximate the original high-dimensional solution space via a low-dimensional subspace, constructed by the Proper Orthogonal Decomposition (POD) method based on an ensemble of snapshots from the full-order model at selected time instances. First, we rigorously establish the spatio-temporal strong convergence rates between the mild solution and the reduced-order solution. Second, in large-sample simulations, the reduced-order basis exhibits a certain generalization capability in capturing the average behavior of the numerical solutions. Numerical experiments are provided to verify the theoretical error estimates and to demonstrate the effectiveness of the proposed method.
-
A corrected Crank–Nicolson scheme for the time fractional parabolic integro-differential equation with nonsmooth dataThis paper proposes a corrected Crank–Nicolson (CN) scheme for solving time fractional parabolic integro-differential equations which involve Caputo time fractional derivative and fractional Riemann–Liouville (R-L) integral. The weighted and shifted Grünwald–Letnikov (WSGL) formulae is adopted to approximate the time fractional Riemann–Liouville integral. The Crank–Nicolson scheme is applied to approximate the Caputo time fractional derivative. After appropriating corrections, the proposed scheme attains the optimal convergence order of O(\tau^2) with respect to the time step size \tau for both smooth and nonsmooth data at any fixed time $t$. When combined with the Galerkin finite element method for spatial discretization, it forms a fully discrete scheme. The second-order error estimate for this scheme is rigorously established using the Laplace transform technique and verified by some numerical examples.
-
Dynamic pricing-driven load optimization in islanded microgrid for home energy management systemsIn order to maximize residential energy use and reduce electricity costs, home energy management systems (HEMS), are crucial. A distinct dynamic pricing-driven load optimization technique for HEMS running in islanded mode where grid access is either limited or nonexistent is presented in this paper. Incorporating important distributed energy resources like photovoltaic (PV) systems, electric vehicles (EVs), battery energy storage systems (BESS), and limited grid access, the optimal schedule is also used for real-time dynamic pricing analysis. A planned short-duration outage and a full 24-hour islanding scenario are the two different outage scenarios that are assessed. In short-duration outages, grid dependency decreases to roughly 10% in the spring and approximately 50% in the summer and winter, according to a thorough seasonal analysis conducted in the spring, summer, and winter. The suggested approach guarantees total self-sufficiency in the 24-hour outage scenario, with local resources satisfying load demands in full.
-
Banal deception and human-AI ecosystems: A study of people’s perceptions of LLM-generated deceptive behaviourLarge language models (LLMs) can provide users with false, inaccurate, or misleading information, and we consider the output of this type of information as what Natale calls ‘banal’ deceptive behaviour [53]. Here, we investigate peoples’ perceptions of ChatGPT-generated deceptive behaviour and how this affects people’s behaviour and trust. To do this, we use a mixed-methods approach comprising of (i) an online survey with 220 participants and (ii) semi-structured interviews with 12 participants. Our results show that (i) the most common types of deceptive information encountered were over-simplifications and outdated information; (ii) humans’ perceptions of trust and chat-worthiness of ChatGPT are impacted by ‘banal’ deceptive behaviour; (iii) the perceived responsibility for deception is influenced by education level and the perceived frequency of deceptive information; and (iv) users become more cautious after encountering deceptive information, but they come to trust the technology more when they identify advantages of using it. Our findings contribute to understanding human-AI interaction dynamics in the context of Deceptive AI Ecosystems and highlight the importance of user-centric approaches to mitigating the potential harms of deceptive AI technologies.
-
Numerical algorithms for nonlinear fractional stochastic Volterra-type equationIn this work, we investigate a class of nonlinear stochastic Volterra-type evolution equations, which can be regarded as an extension of the results reported in Qiao et al. (Fract Calc Appl Anal 27:1136–1161, 2024). For such equations, we propose an Euler scheme and rigorously establish the existence, uniqueness, and regularity of the solution. Moreover, we present the detailed numerical implementation of the scheme and derive the corresponding error estimates.
-
Carbon fiber-reinforced piezoelectric nanocomposites: Design, fabrication and evaluation for damage detection and energy harvestingCarbon fiber-reinforced polymers (CFRPs) can be used in aging infrastructures as a reinforcement because of their excellent mechanical properties, and they can also be used in the support maintenance and repair work of these structures. However, the development of CFRPs as reinforcement while achieving self-powered damage detection is still challenging. Herein, a sodium potassium niobate (KNN) nanoparticle-filled epoxy (KNN–EP) plate was fabricated and combined with advanced CFRP electrodes. The obtained composites exhibited dramatically enhanced mechanical properties. In addition, CFRP contributed to the energy harvesting output (peak-to-peak output voltage V p p = 7.25 mV), which was over 600 % higher than that of the KNN–EP plate. Thus, this composite could work as a force sensor for damage detection. In the end-notch bending test, the voltage signals generated by CFRP/KNN–EP composite accurately corresponded to the crack growth, which could provide the real-time crack state and prediction of fracture occurrence. Therefore, this work provided a new strategy for structural enhancement and kinetic energy harvesting, which can be used to detect damage behavior in infrastructures.
-
Numerical approximation for a stochastic time-fractional cable equationAn efficient numerical method is proposed to address a stochastic time-fractional cable equation driven by fractionally integrated additive noise. Under the reasonable assumptions, we rigorously establish for the first time, the existence, uniqueness, and regularity of the mild solution for this equation. For spatial discretization, a semi-discrete scheme is constructed employing the Galerkin FEM, and the optimal spatial error estimate is derived based on the semigroup approach. In temporal discretization, a piecewise constant function is introduced to approximate the noise, leading to the formulation of a regularized stochastic time-fractional cable equation. A detailed proof of the temporal error estimates is provided via the semigroup approach. Numerical experiments demonstrate that the temporal convergence order attains O ( τ 1 / 2 ) for initial data of either smooth or non-smooth type. The order is independent of the parameters α 1 ∈ ( 0 , 1 ) , α 2 ∈ ( 0 , 1 ) , and β ∈ ( 0 , 1 ) in the equation. These results perfectly align with the theoretical predictions.
-
Correction to: Visualization for epidemiological modelling: challenges, solutions, reflections and recommendations (2022) by Dykes et al.In the original version of this article, references 113–120, 123–140 and 143 were incorrectly numbered. This has been corrected on the publisher’s website.
-
Erratum to “Combined heat and power from the intermediate pyrolysis of biomass materials: Performance, economics and environmental impact” [Appl. Energy 191 (2017) 639–652]The publisher regrets that Fig. 3 in Page 643 contains errors in data labels.
-
Correction: Existence, uniqueness and regularity for a semilinear stochastic subdiffusion with integrated multiplicative noiseThe original online version of this article was revised: The co-author’s name was misspelled. The co-author's name was spelled Ziqiang Li but should have been Zhiqiang Li. The original version is corrected.
-
Same structures, different settings: exploring computing capital and participation across cultural contextsThe number of people choosing to study computing in higher education remains low. Previous research has developed a research instrument to identify factors underlying student participation grounded in Bourdieu’s sociocultural theory. This study replicates and extends the original study, which identified key social, cultural, and psychological factors linked to computing education participation in Sweden. Using the validated research instrument, we distributed a survey across 11 UK universities, gathering responses from 131 students. Through Confirmatory Factor Analysis, we assessed the robustness of the original study’s constructs — career interest, subject-specific interest, influence from family and friends, confidence, and sense of belonging — and their relationship to subject choice in computing. After model refinements, the replication confirmed and validated the factor structure, supporting the stability of these constructs and their relationship to computing subject choice across cultural contexts. In addition, the current study adds additional open-ended questions to the research instrument to help explain the quantitative results. A thematic analysis further explains the correlation between previous experience, social influence, confidence, and gender, and how that relates to participation in the field. By replicating and extending the original study’s methodology, this research evaluates the reliability and generalisability of its conclusions, contributing to the evidence base needed to design interventions that broaden participation in computing education.
-
Tomato treatment with chemical inducers reduces the performance of Spodoptera littoralis (Lepidoptera: Noctuidae)The evolving understanding of plant signaling pathways has promoted the possibility of using chemical inducers as an effective tactic for crop protection. In this study, under greenhouse conditions, we conducted a growth assay of Spodoptera littoralis (Boisduval) larvae on tomato plants treated with BTH (S-methyl benzo [1, 2, 3] thiadiazole 7 carbothioate) as a salicylic acid mimic, PDJ (propyl [1RS, 2RS]-[3-oxo-2-pentylcyclopentyl] acetate) as a jasmonic acid-mimic or both chemicals as a combined treatment. The larval body weight of S. littoralis was drastically reduced with each chemical compared to control plants, and there was a significant synergistic interaction. Overall, the total weight gain of surviving larvae fed on treated plants was distinctly tenfold less than for those fed on control plants. Moreover, incorporating the chemical inducers in artificial diets had no direct or toxic impact on the larval body weight of S. littoralis under laboratory conditions. Larval survival rates were significantly lower (35–40 %) on treated plants with either combined or independent inducers’ treatments compared with control plants after 15-day feeding. In contrast, incorporating the chemical inducers in artificial diets had no direct effect on larval survival rates under laboratory conditions. The applied concentrations of BTH and PDJ had no detectable phytotoxicity to tomato plants. Our results demonstrate that BTH and PDJ can act synergistically when applied to tomato to reduce the performance of S. littoralis. These findings stress that the application of chemical inducers could provide an environment-friendly tactic to help manage insect pests and thereby play multiple roles in improving the overall plant resistance to herbivore pests.
-
Less is more: Treatment with BTH and Laminarin reduces herbivore-induced volatile emissions in maize but increases parasitoid attractionChemical plant strengtheners find increasing use in agriculture to enhance resistance against pathogens. In an earlier study, it was found that treatment with one such resistance elicitor, BTH (benzo-(1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester), increases the attractiveness of maize plants to a parasitic wasp. This surprising additional benefit of treating plants with BTH prompted us to conduct a series of olfactometer tests to find out if BTH and another commercially available plant strengthener, Laminarin, increase the attractiveness of maize to three important parasitic wasps, Cotesia marginventris, Campoletis sonorensis, and Microplitis rufiventris. In each case, plants that were sprayed with the plant strengtheners and subsequently induced to release volatiles by real or mimicked attack by Spodoptera littoralis caterpillars became more attractive to the parasitoids than water treated plants. The elicitors alone or in combination with plants that were not induced by herbivory were not attractive to the wasps. Interestingly, plants treated with the plant strengtheners did not show any consistent increase in volatile emissions. On the contrary, treated plants released less herbivore-induced volatiles, most notably indole, which has been reported to interfere with parasitoid attraction. The emission of the sesquiterpenes (E)-β-caryophyllene, β-bergamotene, and (E)-β-farnesene was similarly reduced by the treatment. Expression profiles of marker genes showed that BTH and Laminarin induced several pathogenesis related (PR) genes. The results support the notion that, as yet undetectable and unidentified compounds, are of major importance for parasitoid attraction, and that these attractants may be masked by some of the major compounds in the volatile blends. This study confirms that elicitors of pathogen resistance are compatible with the biological control of insect pests and may even help to improve it.
-
Oral secretions affect HIPVs induced by generalist (Mythimna loreyi) and specialist (Parnara guttata) herbivores in ricePlants synthesize variable mixtures of herbivore-induced plant volatiles (HIPVs) as part of their evolutionary conserved defense. To elucidate the impact of chewing herbivores with different level of adaptation on HIPV profiles in rice, we measured HIPVs released from rice seedlings challenged by either the generalist herbivore Mythimna loreyi (MYL) or the specialist Parnara guttata (PAG). Both herbivores markedly elicited the emission of HIPVs, mainly on the second and third days after attack compared to control plants. In addition, side-by-side HIPV comparisons using MYL and PAG caterpillars revealed that generalist feeding induced comparably more HIPVs relative to specialist, particularly on day two as highlighted by multivariate analysis (PLS-DA) of emitted HIPVs, and further confirmed in mimicked herbivory experiments. Here, mechanically wounded plants treated with water (WW) released more VOCs than untreated controls, and on top of this, oral secretions (OS) from both herbivores showed differential effects on volatile emissions from the wounded plants. Similar to actual herbivory, MYL OS promoted higher amounts of HIPVs relative to PAG OS, thus supporting disparate induction of rice indirect defenses in response to generalist and specialist herbivores, which could be due to the differential composition of their OS. (196 words).
-
Development, consumption rates and reproductive biology of Orius albidipennis reared on various preyThe predatory bug Orius albidipennis (Reuter) (Hemiptera: Anthocoridae) has tremendous potential as a biological control agent, especially in its native range around the Mediterranean Basin and East Africa. The need to exploit native biological control agents is growing in importance as concerns over the introduction of non-native species continue to increase. However, little is known of the effects of different prey on development and reproduction of O. albidipennis compared with other species of Orius. Therefore, we compared the development, survival, reproductive biology, and prey consumption of O. albidipennis when fed eggs of Ephestia kuehniella Zeller, Tetranychus urticae Koch, and Trialeurodes vaporariorum (Westwood), and larvae of Gynaikothrips ficorum (Marchal), under laboratory of 26 ± 1°C, 60 ± 10% RH and 16L:8D photoperiod. Individuals were reared from the neonate stage until death on one of the four prey types. The type of prey had profound effects on all measured performance traits. The highest survival rate was recorded for nymphs that were fed on E. kuehniella eggs, while the lowest survival rate was observed for those fed on T. vaporariorum eggs. The shortest nymphal period was recorded for nymphs fed on E. kuehniella eggs, while the longest was measured for those fed on T. urticae eggs. During the nymphal period, O. albidipennis consumed significantly more eggs of T. urticae than other prey types, whereas the lowest number of consumed prey were eggs of E. kuehniella. Adult females and males consumed significantly more T. urticae eggs than other types of prey. However, Orius albidipennis females showed the highest fecundity when fed on E. kuehniella eggs, and the lowest when fed on T. vaporariorum eggs. Adult females and males that fed on G. ficorum larvae had significantly longer life spans compared with those fed other prey. Because of their relatively rapid development and high fecundity, O. albidipennis fed E. kuehniella eggs had a significantly higher net reproductive rate (Ro) and intrinsic rate of increase (rm) than O. albidipennis fed other prey types. Overall, eggs of E. kuehniella were the most suitable diet for nymphs and adults of O. albidipennis. Although less suitable, O. albidipennis could survive and reproduce on the other prey types, which is a favourable attribute in biological control agents. These results on the effect of different prey types on development and reproduction of O. albidipennis will also contribute to the development of mass rearing programs for biological control agents in developing countries, such as Egypt.
-
The maize lipoxygenase, ZmLOX10, mediates green leaf volatile, jasmonate and herbivore‐induced plant volatile production for defense against insect attackFatty acid derivatives are of central importance for plant immunity against insect herbivores; however, major regulatory genes and the signals that modulate these defense metabolites are vastly understudied, especially in important agro-economic monocot species. Here we show that products and signals derived from a single Zea mays (maize) lipoxygenase (LOX), ZmLOX10, are critical for both direct and indirect defenses to herbivory. We provide genetic evidence that two 13-LOXs, ZmLOX10 and ZmLOX8, specialize in providing substrate for the green leaf volatile (GLV) and jasmonate (JA) biosynthesis pathways, respectively. Supporting the specialization of these LOX isoforms, LOX8 and LOX10 are localized to two distinct cellular compartments, indicating that the JA and GLV biosynthesis pathways are physically separated in maize. Reduced expression of JA biosynthesis genes and diminished levels of JA in lox10 mutants indicate that LOX10-derived signaling is required for LOX8-mediated JA. The possible role of GLVs in JA signaling is supported by their ability to partially restore wound-induced JA levels in lox10 mutants. The impaired ability of lox10 mutants to produce GLVs and JA led to dramatic reductions in herbivore-induced plant volatiles (HIPVs) and attractiveness to parasitoid wasps. Because LOX10 is under circadian rhythm regulation, this study provides a mechanistic link to the diurnal regulation of GLVs and HIPVs. GLV-, JA- and HIPV-deficient lox10 mutants display compromised resistance to insect feeding, both under laboratory and field conditions, which is strong evidence that LOX10-dependent metabolites confer immunity against insect attack. Hence, this comprehensive gene to agro-ecosystem study reveals the broad implications of a single LOX isoform in herbivore defense.
-
Synergies and trade‐offs between insect and pathogen resistance in maize leaves and rootsDetermining links between plant defence strategies is important to understand plant evolution and to optimize crop breeding strategies. Although several examples of synergies and trade-offs between defence traits are known for plants that are under attack by multiple organisms, few studies have attempted to measure correlations of defensive strategies using specific single attackers. Such links are hard to detect in natural populations because they are inherently confounded by the evolutionary history of different ecotypes. We therefore used a range of 20 maize inbred lines with considerable differences in resistance traits to determine if correlations exist between leaf and root resistance against pathogens and insects. Aboveground resistance against insects was positively correlated with the plant's capacity to produce volatiles in response to insect attack. Resistance to herbivores and resistance to a pathogen, on the other hand, were negatively correlated. Our results also give first insights into the intraspecific variability of root volatiles release in maize and its positive correlation with leaf volatile production. We show that the breeding history of the different genotypes (dent versus flint) has influenced several defensive parameters. Taken together, our study demonstrates the importance of genetically determined synergies and trade-offs for plant resistance against insects and pathogens.






