Life Cycle Parameters Research Articles

Elucidating the life history parameters of Culicoides oxystoma (Diptera: Ceratopogonidae) under varied substrate compositions and temperatures.

A comprehensive study was conducted on the life history parameters of an important vector Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae), to standardize potential rearing procedures. Data on life history traits and rearing conditions are crucial for establishing laboratory colony and conducting vector competence-based studies utilizing specimens with a known rearing history. Six different substrate compositions were used to rear the larvae: S1: habitat mud containing cattle manure + nutrient broth + yeast, S2: yeast, S3: habitat mud containing cattle manure + nutrient broth, S4: nutrient broth, S5: sterile (habitat mud consisting cattle manure + nutrient broth + yeast) and S6: tap water. Gravid females preferred ovipositing on beds moistened with tap water compared to distilled water. Egg hatching recorded minimal (3%) in the sterile substrate (S5), hinting at the role of live microbial load. Progression of larval instars got disrupted at 1st instars in S5 and S6. Larval survival and adult emergence were the highest in S1 and the lowest in S4, indicating that S1 is highly effective in the rearing of this species. The life cycle parameters and duration between transitional stages were evaluated at 15 °C, 20 °C, 26 °C, 30 °C, and 35 °C using rearing substrate S1. The highest larval survival (>70%) and adult emergence (69%) were achieved at 26 °C. The duration from egg to adult was 16 to 20 d at 35 °C, 18 to 24 d at 26 °C, but up to 36 d at 15 °C. Elucidating the effective rearing conditionalities of this important vector species will be helpful to study the transmission cycles of pathogens.

Biology and Management of Spodoptera litura on Cabbage in Laboratory Conditions

Spodoptera litura, commonly known as the tobacco cutworm, is a significant polyphagous pest of cabbage and other cruciferous crops. This study investigated the biology and evaluated the efficacy of different management strategies against Spodoptera litura on cabbage under laboratory conditions. Observations on the life cycle parameters, including incubation period (3.0±0.0 days), larval duration (29.60 days), pupal duration (8.80±1.48 days), and adult longevity (8.20±0.92 days, female, and 5.90±1.10 days, male), were recorded. Different management strategies, such as neem kernel extract (NSKE) containing 0.15% azadirachtin, Beauveria bassiana (Green Beauveria @ 1 × CFU/ml and Multiplex Baba 2 × CFU/ml), and newer insecticides (Novaluron, 10% EC, and Spinosad, 2.5% SC), were evaluated for their efficacy in controlling larval populations. Spinosad (0.025 %) and novaluron (0.01 %) when treated on I, II, III and IV instar larva resulted in 100% mortality in only 3 DAT while Green Beauveria (2% and 4%) was able to kill only 43.33% of I and II instar larvae in 3 DAT and Multiplex Baba (4%) 10% and 16.67% on III and IV instar larvae, respectively. The application of NSKE (0.2%) was only effective on I and III instar larvae with a mortality rate of 33.33 and 11.11% respectively. Thus, the results revealed that chemical insecticides were highly effective than Beauveria bassiana and NSKE. This information can be utilized to develop sustainable and eco-friendly pest management programs for Spodoptera litura on cabbage in field conditions.

Application of a Generalized Utility Function to Determine the Optimal Composition of Geopolymer Mortar.

The aim of the presented research was to evaluate the impacts of modifications to the technical properties of fly ash-based geopolymer composites, particularly focusing on enhancing the thermal insulation. Through the utilization of a generalized utility function, optimal dosages of additives such as perlite sand, waste perlite powder, and cenospheres were determined. The study aimed to increase the thermal insulation of the composites while maintaining satisfactory compressive and flexural strength. The results indicated that dosages of perlite dust and cenospheres significantly influenced the technical characteristics of the composites; an exception was the flexural strength, for which these modifications did not show a statistically significant effect. The average compressive strength values, except for the mixes with poor workability, were at least 3.5 MPa (RILEM class II). Notably, a balanced dosage of additives, around 75 kg per cubic meter of the mixture in the total mixture, yielded the most favorable outcomes in terms of thermal isolation (0.18-0.24 W/(m·K) and workability (cone immersion 40-70 mm). Additionally, perlite dust emerged as a potentially superior modifier due to its waste origin. However, further analysis considering life cycle parameters including the carbon footprint and water footprint would be necessary to validate this claim. Overall, the study highlights the potential of utilizing perlite-based modifiers to enhance the thermal insulation of geopolymers while addressing environmental concerns.

Сезонная активность и сроки появления сеголеток настоящих ящериц (Sauria, Lacertidae) Карадагского заповедника в Крыму и их связь с климатическими параметрами

In the course of multi-year field research (2002–2022, and partially 2023) in the Karadag Nature Reserve (southeastern Crimea; 44.9º N, 35.2º E) the seasonal activity frame and terms of the emergence of juveniles were studied in two common species of lacertids: the Balkan wall lizard (Podarcis tauricus) and the Crimean rock lizard (Darevskia lindholmi). Activity during the winter period is characteristic for both species: over 22 years of observations, P. tauricus and D. lindholmi were observed in the winter months during 20 and 16 seasons, respectively. In P. tauricus the average for all years dates of the first and last observations of active individuals are February 13 and December 4; those in D. lindholmi are February 18 and November 26. The length of the activity period, determined by the dates of the first and last records, in P. tauricus is 65–91% of the total duration of the year, and in D. lindholmi is 62–89% of the year. The duration of the period of full activity (from the beginning of the species’ regular activity to the hibernation) is 236–321 days (273 days on average) in P. tauricus, and 227–302 days (260 days on average) in D. lindholmi. Egg-laying in P. tauricus occurs mainly in May–July (two clutches per season), while in D. lindholmi it occurs in July, but may continue into August (usually the only clutch per year). Therefore, the average for all years dates of the first registration of hatchlings differ by approximately seven weeks: July 12 in P. tauricus, August 29 in D. lindholmi. The timing of the emergence of yearlings of both species is positively correlated at a statistically significant level. In both species, a statistically significant correlation with the climatic characteristics of the area of study was found for a number of phenological phenomena. In many cases, the relationship between the phases of the lizards' life cycle and climatic parameters at the trend level was confirmed.

Multi-Omics and Physiological Analysis Reveal Crosstalk Between Aphid Resistance and Nitrogen Fertilization in Wheat.

The availability of nitrogen (N) can dramatically influence crops resistance to herbivorous insects. However, the interaction between N fertilization and crop resistance to insects is not well understood. In this study, the effects of N fertilization on the grain aphid (Sitobion miscanthi) were investigated using three wheat (Triticum aestivum) cultivars with different aphid resistances. We measured aphid life cycle parameters, fecundity, survival rate, weight and feeding behavior, in conjunction with wheat metabolomics, transcriptomics and alien introgression analysis. Our results demonstrated that higher N application benefits aphid feeding across all three wheat cultivars. We also reveal that the highly resistant cultivar (ZM9) can only exert its resistance-advantage under low N fertilization, losing its advantage compared to moderately resistant cultivar YN19 and susceptible cultivar YN23 under higher N fertilization. The effects of N fertilization on wheat-aphid interactions were due to changes in the regulation of carbon and nitrogen metabolism. Integration of multi-omics highlighted specific aphid-induced differentially expressed genes (DEGs, e.g., TUB6, Tubulin 6; ENODL20, Early nodulin-like protein 20; ACT7 Actin 7; Prx47, Peroxidase 47) and significantly different metabolites (SDMs, e.g., crotonoside, guanine, 2'-O-methyladenosine, ferulic acid) in ZM9. Additionally, we report the unique SDMs-DEGs interactions, associated with introgression during wheat domestication, may help infer aphid resistance. In summary, this study provides new insights into the relationships between N fertilization practices, defense responses and integrated pest management for sustainable wheat production.

Detection device of the nuclear power plant electric actuator development and application

Abstract In order to realize the parameters of the full life cycle of the nuclear power plant (new purchase, operation, use, maintenance, and scrap) parameter, we improve the multi-parameter of the entire working conditions (air rotation, plugging, opening/closing, different load rates) under different conditions of the source traceability. For the construction of the chain and mastering of the offline detection technology of electric actuators, this article introduces an electric actuator detection device and detection method designed based on the principle of hydraulic dynamics. Device and computer, data analysis processing software form a complete set of equipment to detect the torque, speed, and power output of the electric actuator.

Evolution of virulence in emerging epidemics: from theory to experimental evolution and back.

The experimental validation of theoretical predictions is a crucial step in demonstrating the predictive power of a model. While quantitative validations are common in infectious diseases epidemiology, experimental microbiology primarily focuses on the evaluation of a qualitative match between model predictions and experiments. In this study, we develop a method to deepen the quantitative validation process with a polymorphic viral population. We analyse the data from an experiment carried out to monitor the evolution of the temperate bacteriophage λ spreading in continuous cultures of Escherichia coli. This experimental work confirmed the influence of the epidemiological dynamics on the evolution of transmission and virulence of the virus. A variant with larger propensity to lyse bacterial cells was favoured in emerging epidemics (when the density of susceptible cells was large), but counter-selected when most cells were infected. Although this approach qualitatively validated an important theoretical prediction, no attempt was made to fit the model to the data nor to further develop the model to improve the goodness of fit. Here, we show how theoretical analysis-including calculations of the selection gradients-and model fitting can be used to estimate key parameters of the phage life cycle and yield new insights on the evolutionary epidemiology of the phage λ. First, we show that modelling explicitly the infected bacterial cells which will eventually be lysed improves the fit of the transient dynamics of the model to the data. Second, we carry out a theoretical analysis that yields useful approximations that capture at the onset and at the end of an epidemic the effects of epidemiological dynamics on selection and differentiation across distinct life stages of the virus. Finally, we estimate key phenotypic traits characterizing the two strains of the virus used in our experiment such as the rates of prophage reactivation or the probabilities of lysogenization. This study illustrates the synergy between experimental, theoretical, and statistical approaches; and especially how interpreting the temporal variation in the selection gradient and the differentiation across distinct life stages of a novel variant is a powerful tool to elucidate the evolutionary epidemiology of emerging infectious diseases.

The Effect of Soil Type and Moisture on the Development of Forensically Important Megaselia scalaris and Dohrniphora cornuta (Diptera: Phoridae).

Necrophagous phorid flies are common insects found on buried corpses, and their developmental data play a crucial role in estimating the post-burial interval (PBI). This study aimed to investigate the effects of soil type and moisture content on some life cycle parameters of two forensically important insects, Megaselia scalaris (Loew, 1866) and Dohrniphora cornuta (Bigot, 1857) (Diptera: Phoridae). Larval and pupal survival, development time, and larval body length of M. scalaris and D. cornuta were observed in three different soil types (loamy sand, sandy loam A, and sandy loam B) with six moisture contents (0%, 20%, 40%, 60%, 80%, and 100%). The results indicated that soil types, soil moisture, and their interaction significantly influenced the growth and development of both species, with moisture being the most influential factor. In each soil, 20% and 40% moisture contents were more suitable for their growth and development. Both the development time and maximum larval body length were significantly different among soil types and moisture contents. The larval period of both species lasted the longest in all soils with 0% moisture content. Additionally, a regression analysis of the relationship between larval body length and development time was performed at different moisture contents in three soils. This study expanded our knowledge of the factors that influence the development of necrophagous insects and provided some reference data for applications of M. scalaris and D. cornuta in PBI estimation.

Research on the strategy for average consensus control of flywheel energy storage array system based on lifecycle

In the domain of clean energy, the flywheel energy storage array system (FESAS) is widely employed for efficient and renewable energy storage to stabilize power grids and smooth power variations. However, managing the lifecycle of FESAS and achieving coordinated control presents a considerable challenge. This study integrates a lifecycle parameter based on the average consensus algorithm, enabling flywheels with longer lifecycles to handle additional charging and discharging tasks, while those with shorter lifecycles participate less. This approach effectively balances flywheel lifecycles and extends the overall lifespan of FESAS. Experimental findings reveal that when the P matrix satisfies the condition of equal row sums or column sums, the power distribution parameters tend toward average consensus, enabling FESAS to efficiently smooth unbalanced power. In undirected graphs, the symmetry of the P matrix causes the auxiliary variables to tend toward average consensus, effectively suppressing unbalanced power. For directed unbalanced graphs, this study proposes Error Balancing Iterative Algorithm (EBTA) to construct a doubly stochastic matrix P, facilitating the convergence of auxiliary variables to average consensus and effectively suppressing unbalanced power. The experimental results validate the efficacy of our proposed approach. This research establishes a theoretical foundation for the intelligent coordinated control of FESAS, highlighting the pivotal role of lifecycle parameters, and offers valuable insights for enhancing the performance and lifespan of FESAS.

Electrification of Agricultural Machinery: One Design Case of a 4 kW Air Compressor

In response to the global pursuit of net-zero carbon emissions, the electrification of agricultural machinery is becoming a significant research and development trend. This study introduces the overall design of a 4 kW air compressor aimed at achieving a green vision for agricultural machinery. The design focuses on providing continuous and stable power and air output using a lithium-ion battery. Durability and cost-effectiveness are prioritized, with a particular emphasis on the Arduino system for integrating battery and motor systems to withstand harsh conditions and ensure ease of maintenance. A permanent magnet brushless motor was selected as the power source, paired with an optimized pulley to supply the proper torque to the air compressor. The system employs an Arduino-based feedback control sensor for air pressure regulation, ensuring energy efficiency. The primary energy source is a 48 V lithium iron phosphate battery, known for its high energy density and safety. The battery design focuses on system integration, addressing specific environmental discharge requirements. The embedded battery management system provides thermal and lifecycle parameter estimation, guaranteeing long-duration power supply and safe operation under various conditions. Unlike traditional fuel-driven systems, lithium iron phosphate batteries do not emit harmful gases, aligning with environmental standards. System integration testing demonstrated that the air pressure feedback control effectively meets the energy-saving requirements by digitally reducing power output as air accumulates in the chamber. Bench testing confirmed that the system performs as designed, achieving the desired results and advancing the goal of sustainable agricultural machinery.

Performance of Hermetia illucens reared on pure, mixed, and sequentially mixed organic wastes regionally available in central Argentina

Abstract Black soldier fly larvae (Hermetia illucens L.) are proficient decomposers of organic matter. We compared experiments with local substrates containing: domestic residues (DR), and brewery wastes (BW) in pure form, or mixed with in two different proportions (BW70 or BW30), and two sequential diets in which larvae were fed first DR and then BW (DR/BW) or vice versa (BW/DR). The effects of the diets on life cycle parameters for mass production of H. illucens larvae were evaluated using general linear mixed models, ANOVA and Kruskal-Wallis. The pure DR diet significantly prolonged the developmental period (47.8 days), although the pupal stage was shorter in larvae fed on this diet (13.8 days). Larval survival was similar between treatments (over 85%), but pupal survival tended to be higher in the mixed diets (over 96%). Larval weights differed significantly between treatments, with mixed diets promoting greater weight gains than pure and sequential diets. Larvae fed a DR/BW diet gained more weight than those fed a BW/DR diet. The highest mean larval weights (0.23 g) were observed in the mixed diet BW70, followed by the sequential diet DR/BW (0.22 g). Mixed diet BW70 also resulted in larger wings and bodies in both sexes. Sequential diet BW/DR and pure diet DR resulted in the smallest adult sizes. Sex ratios varied, favouring male emergence (1.8 M:0.2 F) in pure diet DR and in both sequential mixed diets (1.7 M:0.3 F and 1.3 M:0.7 F, respectively). This study highlights the importance of higher total protein plus carbohydrate concentrations in diets for optimal larval rearing, favouring mixed diets BW70. Carbohydrate-rich substrates should be provided earlier in the cycle to benefit larval and adult performance. Locally available waste vegetable or fruit peels, brewery waste, and spent yerba mate proved to be viable substrates for larval rearing, providing economic and environmental benefits for H. illucens rearing.

Study on Rapid Simulation of the Pre-Cooling Process of a Large LNG Storage Tank with the Consideration of Digital Twin Requirements

The pre-cooling of a large LNG storage tank involves complex phenomena such as heat transfer, low-temperature flow, gas displacement, and vaporization. The whole pre-cooling process could take up to 50 h. For large-scale, full-capacity storage tanks, it is particularly important to accurately control the pre-cooling temperature. Digital twin technology can characterize and predict the full life cycle parameters from the beginning of pre-cooling development to the end and even the appearance of damage in real time. The construction of a digital twin platform requires a large number of data samples in order to predict the operating state of the device. Therefore, a simulation method with high computational efficiency for the pre-cooling process of LNG tanks is of great importance. In this paper, the mixture model and discrete phase model (DPM) are applied to simulate the pre-cooling process of a large LNG full-capacity tank. Following Euler–Lagrange, the DPM greatly simplifies the solution process. Compared with the experimental results, the maximum error of the DPM simulation results is less than 11%. Such a highly efficient simulation method for the large LNG full-capacity storage tank can make it possible to build the digital twin platform that needs hundreds of data model samples.

Insights into the novel Enterococcus faecalis phage: A comprehensive genome analysis.

Enterococcus faecalis, a Gram-positive bacterium, poses a significant clinical challenge owing to its intrinsic resistance to a broad spectrum of antibiotics, warranting urgent exploration of innovative therapeutic strategies. This study investigated the viability of phage therapy as an alternative intervention for antibiotic-resistant E. faecalis, with a specific emphasis on the comprehensive genomic analysis of bacteriophage SAM-E.f 12. The investigation involved whole-genome sequencing of SAM-E.f 12 using Illumina technology, resulting in a robust dataset for detailed genomic characterization. Bioinformatics analyses were employed to predict genes and assign functional annotations. The bacteriophage SAM-E.f 12, which belongs to the Siphoviridae family, exhibited substantial potential, with a burst size of 5.7 PFU/infected cells and a latent period of 20 min. Host range determination experiments demonstrated its effectiveness against clinical E. faecalis strains, positioning SAM-E.f 12 as a precise therapeutic agent. Stability assays underscore resilience across diverse environmental conditions. This study provides a comprehensive understanding of SAM-E.f 12 genomic composition, lytic lifecycle parameters, and practical applications, particularly its efficacy in murine wound models. These results emphasize the promising role of phage therapy, specifically its targeted approach against antibiotic-resistant E. faecalis strains. The nuanced insights derived from this research will contribute to the ongoing pursuit of efficacious phage therapies and offer valuable implications for addressing the clinical challenges associated with E. faecalis infections.

Climate change impacts assessment on railway infrastructure in urban environments

Climate change impacts can escalate the deteriorating rate of infrastructures and impact the infrastructure's functionality, safety, operation and maintenance (O&M). This research explores climate change's influence on urban railway infrastructure. Given the geographical diversity of Sweden, the railway network is divided into different climate zones utilizing the K-means algorithm. Reliability analysis using the Cox Proportional Hazard Model is proposed to integrate meteorological parameters and operational factors to predict the degree of impacts of different climatic parameters on railway infrastructure assets. The proposed methodology is validated by selecting a number of switches and crossings (S&Cs), which are critical components in railways for changing the route, located in different urban railway stations across various climate zones in Sweden. The study explores various databases and proposes a climatic feature to identify climate-related risks of S&C assets. Furthermore, different meteorological covariates are analyzed to understand better the dependency between asset health and meteorological parameters. Infrastructure asset managers can tailor suitable climate adaptation measures based on geographical location, asset age, and other life cycle parameters by identifying vulnerable assets and determining significant covariates. Sensitivity analysis of significant covariates at one of the urban railway stations shows precipitation increment reveal considerable variation in the asset reliability.

Flexible Vis/NIR sensing system for banana chilling injury

The transportation stage of the banana production chain has influence on banana quality and other lifecycle parameters. Certain factors, such as chilling injury (CI), have detrimental effects on bananas, leading to increased losses. The commonly used monitoring and evaluation methods, such as machine vision, face challenges in achieving real-time detection and are susceptible to environmental interference, leading to deviations in the results. Therefore, a flexible visible (Vis)/near-infrared (NIR) real-time sensing system (FVN) was developed for real-time monitoring of the CI status of bananas. The color space of bananas was analyzed and predicted based on the multiple linear regression (MLR) model, and the results showed that the coefficient of determination (R2p) of a* of 0.97, and the residual prediction deviation (RPD) of 4.95, which indicated that the prediction of a* reached a high accuracy. The RPD values for the predictions of L* and b* exceeding 2.5 indicate that the FVN based on the MLR model could be applicable to the majority of market demands. The self-developed classification prediction model (SCP) exhibits evident advantages in predicting the occurrence and elapsed duration of CI, with prediction accuracies of 98.3 % and 95.5 %. In addition, a comprehensive comparative analysis of the FVN is carried out in terms of power consumption and cost, highlighting its great advantages. The application of FVN can effectively reduce the waste of bananas in the market supply chain, greatly alleviate the problem of unpredictable fruit chilling damage, and thus promote more sustainable and cleaner production in the banana industry.

Phytotoxic and Insecticidal Activity of Industrial Hemp (Cannabis sativa L.) Extracts against Plodia interpunctella Hübner—A Potential Sunflower Grain Protectant

The biological activity (contact and contact-digestive toxicity, repellent and fumigant effects, effect on the insect’s development and life cycle parameters) of industrial hemp (Cannabis sativa L.) ethanolic extract was assessed against Plodia interpunctella, the most destructive storage pest of sunflower. Additionally, the study aimed to examine the phytotoxic activity of the extract in order to assess its potential as a sunflower grain protectant. Phytotoxicity assessment was based on the effect on germination energy and seed germination and the activity of antioxidative enzymes, enzymes of the polyphenolic metabolism, and the intensity of lipid peroxidation in sunflower seedlings. The antioxidant capacity and content of phenolic compounds (total phenolics and total tannins) were also measured in seedlings. In the experiments, 70% ethanolic extract of dried flowering buds of industrial hemp (variety Helena) was applied at 0.5%, 1.0% and 2.0% concentrations directly on sunflower seeds. Ethanol solution (70%) was the control. The hemp extract (1% and 2%) revealed medium repellence for P. interpunctella larvae (L3–4) while at 2% concentration it caused 42.5% larval mortality after 72 h. Moreover, the insect’s development was prolonged and fecundity significantly reduced in hemp treatments. The extract did not exhibit fumigant activity. Germination energy and germination of sunflower seeds were stimulated in treatment with 2% hemp extract, while most biochemical parameters of the seedlings were not significantly affected by the hemp extract.

Effects of pesticide formulations containing cypermethrin or tebuconazole, individually and in mixture, on the earthworm Eisenia fetida

The use of pesticides has increased considerably over the past few decades to maximize crop yields. This resulted in the presence of a range of toxic compounds in ecosystems, which may interact with each other, potentially enhancing adverse impacts on wildlife and ecosystem services. The objective of this study was to evaluate potential effects induced by chronic exposure to a mixture of pesticide formulations extensively used in agriculture: one containing cypermethrin (Sherpa 100 EC – SHP) and used as insecticide, the other containing tebuconazole (Spekfree 430 SC – SKF) and used as fungicide. In laboratory experiments, the earthworm Eisenia fetida was exposed for 28 days to the following treatments: control, double recommended field dose (2× FD) and quadruple recommended field dose (4× FD) of SHP or SKF, and mixtures of both formulations in a full factorial design. Effect criteria were mortality, reproduction, growth, respiration rate, and the activity of glutathione S-transferases (GST) and acetylcholinesterase (AChE). No significant effects on the life-cycle parameters of E. fetida, AChE activity or GST activity were observed. Therefore, chronic exposure to levels above the recommended field application doses of SHP and SKF are not expected to cause significant negative effects to the evaluated parameters in Eisenia fetida.

Extended stage duration and diminished fecundity in deltamethrin-resistant Triatoma infestans (Klug, 1834) of the Argentinean Chaco.

Pyrethroid-resistance is an emergent trait in populations of various insect species. For Triatoma infestans (Klug, 1834) (Heteroptera: Reduviidae), the major vector of Chagas disease in the southern part of South America, hotspot areas of pyrethroid-resistance have recently been found in the Chaco Province of Argentina. Resistant condition can reduce fitness of individuals in the absence of insecticide exposure, that is, fitness costs. We evaluated the existence of developmental and/or reproductive costs in T. infestans collected from two areas of pyrethroid-resistance in Chaco Province, Argentina. Three toxicological groups were defined from field-collected insects: susceptible (survival <20%), moderately resistant (survival between 20% and 80%) and highly resistant (survival >80%). Cohorts of the three toxicological groups were followed-up to study life cycle and reproductive parameters. Additionally, we parameterized matrix population growth models. First and IV nymphal stages of the resistant groups exhibited a longer stage duration than susceptible ones. The reproductive days and hatching success showed significant lower values revealing reproductive costs for the resistant groups. Matrix analysis showed lower population growth rates for the resistant groups. Our results support developmental and reproductive costs for pyrethroid-resistant individuals. This trait could be interpreted as lower population recovery ability for pyrethroid-resistant individuals compared to susceptible insects after alternative vector control actions.

Consumption and time use responses to unemployment: Implications for the lifecycle model

AbstractIn this study, we analyse the effects of unemployment on consumption and time use. To do so, we employ a micro panel dataset for the Netherlands containing a large set of expenditure and time use categories. Our results show a small negative effect of unemployment on expenditures, and large positive effects on time spent on home production and leisure activities. We do not find evidence for complementarity between leisure and consumption or for substitution between home production and expenditures. We use our results to estimate a ratio of relevant lifecycle parameters, and show that the point estimates and their precision depend strongly on the expenditure and time use categories considered.

Dietary deprivation reduces the deleterious effects of carbaryl on the survival and activity of both catalase and acetylcholinesterase in earthworms

Dietary restriction (DR) and dietary deprivation (DD) have been shown to be significantly beneficial in terms of lifespan gains and stress alleviation in invertebrate and vertebrate species. Such beneficial effects, however, have yet to be clearly assessed in the presence of chemical stressors. We conducted a comparative evaluation of the toxicity of carbaryl in Eisenia fetida individuals subjected to a full diet (FD), DR and DD. For 14 days, groups of ten worms subjected to FD received 5 g oatmeal, those subjected to DR received 2.5 g oatmeal, and those subjected to DD received 0 g oatmeal weekly. We evaluated concentrations of 0, 7, 14 and 28 mg carbaryl.kg−1 soil and measured effects on survival, reproduction, biomass and biomarkers (Catalase- CAT and acetylcholine esterase- AChE). Carbaryl caused a total inhibition of reproduction in all the treatments. For each diet level, the 14-day LC50 s were higher than 28 mg.kg−1, but the 14-day LC20 s for the earthworms subjected to FD, DR, and DD were 11.24, 20.51 and > 28 mg.kg−1, respectively. This showed that the toxicity of carbaryl consistently decreased with the reduction in nutrients. Carbaryl caused a significant weight loss in the worms subjected to FD in the 7 mg.kg−1 treatment (P = 0.0065). Such weight loss was not found in any of the other treatments and diets. Both CAT and AChE were significantly inhibited in the two highest treatments (P = 0.0071 and P = 0.0073, respectively). Interestingly, the earthworms subjected to DD showed relatively lower biomarker inhibition, indicating a greater tolerance to oxidative and neurotoxic stresses in these starved earthworms. For all endpoints investigated, aside from reproduction, the starved earthworms fared better under carbaryl toxicity than those given the other diets. Overall, a positive correlation was observed between the amount of food and chemical toxicity as mortality rates, AChE and CAT inhibition increased with the increased amount of nutrients given to the worms. These results show that, in the presence of a chemical stressor, the beneficial effects of DR and DD were variably manifest for select lifecycle parameters and biomarker responses, further suggesting dietary reduction as a non-genetic intervention that could help extend lifespan and alleviate stress even under a chemical insult.