14 research outputs found

    The potential of highly nutritious frozen stages of Tyrophagus putrescentiae as a supplemental food source for the predatory mite Amblyseius swirskii

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    Astigmatid mites have potential as supplementary prey items to support generalist predator populations in crops. However, applying living prey mites has some disadvantages; if not predated they have the potential to cause crop damage and allergies. In this study, we evaluated various diets based on the astigmatid mite Tyrophagous putrescentiae (Schrank) as a supplemental food source for the predatory mite Amblyseius swirskii Ahias-Henriot. Eggs and larvae of T. putrescentiae were reared on a diet of dog food (rich in proteins and fat) or bran (rich in carbohydrate); they were offered either frozen or alive, and either with or without cattail pollen (Typha angustifolia L.). Oviposition rate of A. swirskii fed with frozen mite larvae reared on dog food was similar to the rate observed when they were fed with cattail pollen or living prey mites, but developmental time of A. swirskii was longer on this frozen diet than on a diet of living prey mites or pollen. Both living and frozen prey mites were, in contrast with cattail pollen, not suitable for oviposition by western flower thrips, Frankliniella occidentalis Pergande. In a greenhouse study, the use of frozen prey mite stages as supplemental food on chrysanthemum plants allowed populations of A. swirskii to establish, but not increase; in contrast, provision of living prey mites and pollen increased A. swirskii populations on plants. Hence, our study shows that living prey mites, but not frozen prey mites, had the greatest potential as a supplemental food source for A. swirskii.</p

    Differential Response of Sunflower Maintainer and Restorer Inbred Lines to Salt Stress

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    In order to identify of salt tolerant sunflower inbred lines a set of 24 inbred lines were evaluated as a randomized block design with three replications in Isfahan and Zabol in 2017. Salt stress was imposed following seedlings establishment 20 days after planting as irrigation with two (fresh water) and 8 ds.m-2 electrical conductivity. According to the results, there were significant differences among locations and also salt treatment for all measured traits except for flowering time and oil content. There were also significant differences among inbred lines for all of the characteristics which could be used a source for improvement of salt tolerance in sunflower. Salt stress had a negative impact on agronomic futures of the inbred lines. Achene and oil yield had suffered more than other traits with 34 and 31%25 reduction respectively. Phenological traits were affected less than agronomic traits. The inbred lines BGK259 and RGK38 had the highest and lowest achene and oil yield respectively. Three lines BGK259, BGK369 and BGK375 with higher STI expressed as more salt tolerant lines. All 12 maintainer lines had a higher STI than all the 12 restorer lines and were more tolerant. Among the restorers RGK22, RGK15 and RGK2 were more salt tolerant than others. In accordance with STI, TOL and GM indices, principal component analysis differentiated BGK259, BGK369 and BGK375 as the most salt tolerant inbred lines

    Simulation of "Pump and Treat" and Air Sparging for In-Situ Remediation of Contaminated Groundwater

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    Industrial contamination leakage into groundwater resources is increasing during recent years. Unlike surface water resources, lots of contaminants are stable in groundwater. Hence, several technologies, like Pump-and-Treat (PAT) and Air Sparging (AS), are being used in order to remedy contaminated aquifers. Despite of suggestions about using these two technologies together, there is no integrated simulation model for these two technologies. Using existing models for PAT simulation and combining them with AS simulation model, an integrated model for simulation of these technologies in field scale has been developed in this study. In addition to model validation, remediation of Bagher-Shahr aquifer (west of Tehran refinery)  from MTBE by using AS and PAT technologies has been evaluated during a case study. Based on the suggested design for local remediation of MTBE plume in Bagher-Shar aquifer (without facility installation inside the city area) and during a five- year simulation period, mass of contaminant inside the city area is decreased to half of the initial mass

    Enhanced oil recovery through synergy of the interfacial mechanisms by low salinity water alternating carbon dioxide injection

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    During this study, a comprehensive investigation of low salinity water alternating CO2 injection was performed for enhanced oil recovery in oil-wet carbonate reservoirs. A synergy of interfacial mechanisms such as IFT, wettability alteration, CO2 solubility, oil swelling, water shielding effect, and rock dissolution was considered in two and three-phase systems. Results showed that the monovalent ions, such as NaCl or KCl, inhibit the dissolution of carbon dioxide in brine in excess of divalent salt solutions, e.g. CaCl2 or MgCl2 due to the salting-out effect. In addition, more water shielding effect was observed in low salinity formation water than it in low salinity seawater. The significant change in the reservoir wettability of oil/brine/CO2 system compared to oil/brine referred to the CO2 solubility in brine which could cause stronger carbonated water in the reservoir. Consequently, the low salinity alternating CO2 injection overpowers the late-production problem that occurred commonly in conventional WAG injection

    Active and frozen host mite Tyrophagus putrescentiae (Acari : Acaridae) influence the mass production of the predatory mite Blattisocius mali (Acari: Blattisociidae): life table analysis

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    Blattisocius mali (Oudemans) is a candidate predatory mite on some astigmatid mite pests like Tyrophagus putrescentiae (Schrank). In current study, life table parameters of B. mali were comparatively evaluated when fed on mixed life stages, frozen (one day at-20°C) and cold stored (90 days at-20°C and 4°C) eggs of T. putrescentiae. The highest and lowest values of fecundity, total longevity, oviposition period, life span and adult longevity of B. mali were observed when the predator provided with one-day and 90-days frozen eggs (stored at 4°C) of T. putrescentiae, respectively. Moreover, the highest values of net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) of B. mali were obtained by feeding on one-day frozen eggs (23.94 offspring/individual, 0.332 day-1, 1.39 day-1, respectively), without significant differences from the predators reared on alive mixed stages of T. putrescentiae. However, the lowest values of R0 (1.54 offspring/individual), r (0.058 day-1) and λ (1.06 day-1) were recorded when B. mali was reared on 90-days frozen eggs (stored at 4°C). The results, as first evidence of life-history of B. mali, represent not only the potential of the predator as suitable biological control agent against T. putrescentiae, but also the possibility of its mass production by frozen host stages. Provision of one-day frozen eggs of T. putrescentiae were the best choice for B. mali survival and reproduction with no harmful effects of living stages (direct damage, frass and exuviae) on crop

    Association Study Between APOE and TNF- α Gene Variations and Sporadic Alzheimer’s Disease in Iranian Population

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    Objectives: Several studies indicate that amyloid &szlig; (A&szlig;) peptide deposits and neurofibrillary tangles have key roles in pathogenesis and progression of the late-onset Alzhimer&rsquo;s disease. Likewise it has been shown that inflammatory reactions play a significant role as well. Inflammatory mediators such as complement, chemokines and cytokines activators and inhibitors can release from activated microglia and astrocytes, causing neuronal dysfunction and death. One of the most important cytokines is tumor necrosis factor&ndash;&alpha; (TNF-&alpha;). This study was designed and carried out to determine the association between sporadic Alzheimer&rsquo;s disease and the human TNF-&alpha; and APOE gene variations in Iranian population. Methods & Materials: In this case-control study, the role of TNF-&alpha; gene polymorphism was determined in 167 sporadic AD patients and 163 healthy controls. Genomic DNA was extracted using standard salting out method from peripheral lymphocytes and TNF-&alpha;- 850C/T promoter polymorphism was genotyped using PCR/RFLP technique. Comparing the genotype and allelic frequencies were analyzed using chi-square and logistic regression tests by SPSS 11.5. Results: The obtained results indicated that the frequency of TNF-&alpha; -850 heterozygote genotype (CT) was significantly higher in AD patients comparing healthy controls (P=0.038). Although no significant difference were observed in TNF-&alpha; -850 homozygote genotype (TT) and T allele between the studied groups. No interaction was shown between TNF-&alpha; -850 and APOE gene polymorphisms as well. Conclusion: These data suggests the role of TNF-&alpha; -850 TC genotype as a risk factor for AD in Iranian population. Although to show the effects of homozygote genotype (TT) and T allele, a study with a larger sample size maybe indicated

    An Enhanced Grey Wolf Optimizer with a Velocity-Aided Global Search Mechanism

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    This paper proposes a novel variant of the Grey Wolf Optimization (GWO) algorithm, named Velocity-Aided Grey Wolf Optimizer (VAGWO). The original GWO lacks a velocity term in its position-updating procedure, and this is the main factor weakening the exploration capability of this algorithm. In VAGWO, this term is carefully set and incorporated into the updating formula of the GWO. Furthermore, both the exploration and exploitation capabilities of the GWO are enhanced in VAGWO via stressing the enlargement of steps that each leading wolf takes towards the others in the early iterations while stressing the reduction in these steps when approaching the later iterations. The VAGWO is compared with a set of popular and newly proposed meta-heuristic optimization algorithms through its implementation on a set of 13 high-dimensional shifted standard benchmark functions as well as 10 complex composition functions derived from the CEC2017 test suite and three engineering problems. The complexity of the proposed algorithm is also evaluated against the original GWO. The results indicate that the VAGWO is a computationally efficient algorithm, generating highly accurate results when employed to optimize high-dimensional and complex problems

    An Enhanced Grey Wolf Optimizer with a Velocity-Aided Global Search Mechanism

    No full text
    This paper proposes a novel variant of the Grey Wolf Optimization (GWO) algorithm, named Velocity-Aided Grey Wolf Optimizer (VAGWO). The original GWO lacks a velocity term in its position-updating procedure, and this is the main factor weakening the exploration capability of this algorithm. In VAGWO, this term is carefully set and incorporated into the updating formula of the GWO. Furthermore, both the exploration and exploitation capabilities of the GWO are enhanced in VAGWO via stressing the enlargement of steps that each leading wolf takes towards the others in the early iterations while stressing the reduction in these steps when approaching the later iterations. The VAGWO is compared with a set of popular and newly proposed meta-heuristic optimization algorithms through its implementation on a set of 13 high-dimensional shifted standard benchmark functions as well as 10 complex composition functions derived from the CEC2017 test suite and three engineering problems. The complexity of the proposed algorithm is also evaluated against the original GWO. The results indicate that the VAGWO is a computationally efficient algorithm, generating highly accurate results when employed to optimize high-dimensional and complex problems
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