scholarly journals Assessing the Toxic Effects of Insecticides on Honey Bees in the West Gonja District of the Savannah Region of Ghana

2021 ◽  
pp. 226-245
Author(s):  
Joseph Lambon ◽  
Abdul-Rahaman Issahaku
Keyword(s):  
Environmental Protection Agency ◽  
Honey Bees ◽  
Room Temperature ◽  
Toxic Effects ◽  
Experimental Site ◽  
The West ◽  
Experimental Conditions ◽  
Plastic Container ◽  
Farming Communities ◽  
Different Doses

Aims: To examine the toxic effects of insecticides on bees in farming communities in the Savannah Region of Ghana. Study Design:  The study employed five different doses of insecticides to 3 groups of 10 honey bees in each group using 3 types of insecticides. The number of dead bees were registered and used for the estimation of LC50 of each insecticide. Place and Duration of Study: The experiment was conducted at Damongo Agricultural Training College, Ghana, between August 2019 and September 2019. Methodology: We collected bees from farms in the West Gonja District of the Savannah Region of Ghana. Controller Super 2.5 EC, Pyrinex 48 EC and Golan SL were insecticides used for the experiment. Live adult bees were randomly obtained from beehives at 2:00 am from the farms when the bees were not aggressive. The bees were collected by hand and placed into a perforated plastic container and transported from the site of collection to the experimental site. They were allowed to acclimatize to the experimental conditions for a period of three hours under room temperature of 24 °C  and a relative humidity of 49 percent throughout the study. Results: Mortalities were recorded 10 minutes after administering the concentrations and thereafter at every 10 minutes continuously till 60 minutes. The LC50 was calculated using Where N is the number of honey bees in each group Controller Supper 2.5 EC at a concentration of 6.7 ml/L gave the highest mean mortality (10 bees) at the 50th minute while the concentration of 1.0 ml/L gave the lowest mean mortality (0.0 bees) in the same 50th minute. Conclusion: The LC50 for the three insecticides used were within the recommended concentrations provided by the Environmental Protection Agency of Ghana. The overall mortalities occurred when honey bees were exposed to different concentrations of all the three insecticides.

A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Marc E. Segovia ◽  
Martina Kieninger ◽  
Oscar Ventura ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
Reaction Rates ◽  
Composite Model ◽  
Alternative Mechanism ◽  
Radical Intermediate ◽  
Experimental Conditions ◽  
Methyl Group ◽  
Benzyl Radical

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.

A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Marc E. Segovia ◽  
Martina Kieninger ◽  
Oscar Ventura ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
Reaction Rates ◽  
Composite Model ◽  
Alternative Mechanism ◽  
Radical Intermediate ◽  
Experimental Conditions ◽  
Methyl Group ◽  
Benzyl Radical

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.

scholarly journals Pupal cannibalism by worker honey bees contributes to the spread of deformed wing virus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francisco Posada-Florez ◽  
Zachary S. Lamas ◽  
David J. Hawthorne ◽  
Yanping Chen ◽  
Jay D. Evans ◽  
...  
Keyword(s):  
Honey Bees ◽  
Control Strategies ◽  
Virus Transmission ◽  
Experimental Conditions ◽  
Colony Losses ◽  
Viral Pathogen ◽  
Deformed Wing Virus ◽  
Hygienic Behaviour ◽  
Pathogen Virulence ◽  
Comprehensive Knowledge

AbstractTransmission routes impact pathogen virulence and genetics, therefore comprehensive knowledge of these routes and their contribution to pathogen circulation is essential for understanding host–pathogen interactions and designing control strategies. Deformed wing virus (DWV), a principal viral pathogen of honey bees associated with increased honey bee mortality and colony losses, became highly virulent with the spread of its vector, the ectoparasitic mite Varroa destructor. Reproduction of Varroa mites occurs in capped brood cells and mite-infested pupae from these cells usually have high levels of DWV. The removal of mite-infested pupae by worker bees, Varroa Sensitive Hygiene (VSH), leads to cannibalization of pupae with high DWV loads, thereby offering an alternative route for virus transmission. We used genetically tagged DWV to investigate virus transmission to and between worker bees following pupal cannibalisation under experimental conditions. We demonstrated that cannibalization of DWV-infected pupae resulted in high levels of this virus in worker bees and that the acquired virus was then transmitted between bees via trophallaxis, allowing circulation of Varroa-vectored DWV variants without the mites. Despite the known benefits of hygienic behaviour, it is possible that higher levels of VSH activity may result in increased transmission of DWV via cannibalism and trophallaxis.

scholarly journals Responses of quinoa (Chenopodium quinoa Willd.) seeds stored under different germination temperatures

2017 ◽  
Vol 39 (1) ◽  
pp. 83 ◽  
Author(s):  
Andressa Strenske ◽  
Edmar Soares de Vasconcelos ◽  
Vanessa Aline Egewarth ◽  
Neusa Francisca Michelon Herzog ◽  
Marlene De Matos Malavasi
Keyword(s):  
Room Temperature ◽  
Storage Time ◽  
Chenopodium Quinoa ◽  
Seed Vigor ◽  
Continuous Darkness ◽  
Experimental Conditions ◽  
Growing Seasons ◽  
Germinating Seeds ◽  
Germinated Seeds ◽  
Plot Design

In this experiment, we assessed the germination and vigor of quinoa seeds packed in paper bags and stored at room temperature for 36, 85, 119, 146, 177 and 270 days. The seeds were harvested under experimental conditions in Marechal Candido Rondon, Paraná, during the 2012/13 growing seasons. Four replicates of 100 seeds each were established for each storage time, and the seeds were evaluated, on paper, based on the BOD under the following experimental temperature conditions: alternating temperatures of 20 and 30°C and a constant temperature of 25°C. The seeds from both treatments were subject to seven-hour photoperiods and 25°C under continuous darkness. The germinated seeds were counted daily for eight days after sowing, and we evaluated the percentages of normal and abnormal seedlings and the germination index. The experimental design was completely randomized using a split-plot design. Increasing the storage time decreased the percentage of germinated seeds and seed vigor due to the increased number of abnormal seedlings. Over the 430-day study period, quinoa seed germination completely declined under the experimental conditions. The final number of germinating seeds should be evaluated 7 days after the beginning of the germination test. 

Rainwater effect on bearing strength of glass–epoxy laminated composite pinned joints

2016 ◽  
Vol 50 (30) ◽  
pp. 4269-4278 ◽  
Author(s):  
Onur Sayman ◽  
Ümran Esendemir
Keyword(s):  
Room Temperature ◽  
Failure Modes ◽  
Failure Load ◽  
Weight Ratio ◽  
Laminated Composite ◽  
Hole Diameter ◽  
Plastic Container ◽  
Specimen Width ◽  
Bearing Load ◽  
Pinned Joints

Composite materials are used in areas that have varying environmental conditions due to their advantages such as generally higher stiffness- and strength-to-weight ratio, and corrosion resistance compared to metallic alloys. This experimental study is carried out to investigate the bearing strengths and failure modes of woven glass–epoxy composite pinned joints subjected to rainwater. The specimens were immersed in rainwater in a closed plastic container indoors for 20 month periods at room temperature. The ratio of edge-distance-to-hole diameter (E/D) and the ratio of the specimen width-to-hole-diameter (W/D) were selected as parameters. Failure modes were determined by observing the failure regions on the specimens. Damage of immersed and unimmersed specimens was examined using scanning electron misroscopy for the same failure load. Experimental results showed that the bearing load values obtained from the specimens immersed in rainwater decreased in comparison to unimmersed specimens.

scholarly journals Electroless and Electrodeposition of Silver from a Choline Chloride-Based Ionic Liquid

2015 ◽  
Vol 58 (2) ◽  
pp. 66-73
Author(s):  
Muhammad Rostom Ali ◽  
Muhammad Ziaur Rahman ◽  
Siddhartha Sankar Saha
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Choline Chloride ◽  
Dip Coating ◽  
Constant Current ◽  
Electrolytic Deposition ◽  
Cathodic Current ◽  
Experimental Conditions ◽  
Constant Potential ◽  
Potential Methods

The electroless and electrolytic deposition of silver from a solution containing silver nitrate in either an ethylene glycol (EG)-choline chloride based or a urea-choline chloride based ionic liquids has been carried out onto steel and copper cathodes by simple immersion, constant current and constant potential methods at room temperature. It has been found that electroless silver deposits of up to several micronshave been obtained by dip coating from both urea and EG based ionic liquids without the use of catalysts. The influences of various experimental conditions on electrodeposition and morphology of the deposited layers have been investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It has been observed that crack free bright metallic coloured silver coatings can be obtained from both EG and urea based ionic liquids at the applied deposition potentials up to -0.40 V and applied deposition current densities up to -5.0 A m-2 at room temperature. The cathodic current efficiency for the deposition of Ag is about 99%.

scholarly journals Phyto-toxic Influence of an Atrazine-based Selective Herbicide – Arda-force® on Onions (Allium cepa L)

2020 ◽  
pp. 40-46
Author(s):  
Doris Fovwe Ogeleka ◽  
Esther Obasi
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Allium Cepa ◽  
Environmental Protection Agency ◽  
Toxic Effects ◽  
Root Growth Inhibition ◽  
Allium Cepa L ◽  
Test Concentration ◽  
Maximum Root ◽  
Selective Herbicide

Introduction: The constant impact on the environment occasioned by pollution, indiscriminate application of agricultural chemicals, security challenges and crisis in the Niger Delta ecological area of Nigeria has caused severe damage to plants, soil organisms and humans. Aim and Methodology: In this research, onions (Allium cepa L) was exposed to varying concentrations of an atrazine-based selective herbicide Arda-force® to estimate the phyto-toxic effects on the plant species using the Organization for Economic Co-operation and Development, (OECD) protocol #208. Results: The mean effective concentration (EC50) using root growth inhibition produced indications of phyto-toxicity to the exposed species at a concentration of 0.55 ± 0.06 mg/L. Similarly, the maximum root growth inhibition efficiency relative to the control was 65% as recorded in the highest test concentration of 1.25 mg/L. Discussion: The study indicated that constant application / indiscriminate use of the herbicide Arda-force® could cause deleterious influence on these plant and vegetable species, daily consumed by humans as a rich source of anti-oxidants. Conclusion: This study concluded that atrazine-based herbicide Arda-force® used in this assessment resulted in phyto-toxic effects to Allium cepa L. At the exposed concentrations of the herbicide to non-target specie – Allium cepa L. that are integral parts of the ecosystems, the ‘‘harmless’’ status of atrazine acclaimed by the United State Environmental Protection Agency (USEPA) is still very much in doubt.

scholarly journals Study of the Cryopreservation Conditions for seed Materials of Chartolepis intermedia Boiss.

2021 ◽  
Vol 38 ◽  
pp. 00046
Author(s):  
Margarita Ishmuratova ◽  
Saltanat Tleukenova ◽  
Alibek Ramasanov ◽  
Elena Gavrilkova ◽  
Dmitrii Ageev
Keyword(s):  
Seed Germination ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Germination Rate ◽  
Plastic Container ◽  
In The Wild ◽  
First Time ◽  
Karaganda Region

For the first time, the depending of germination rate and energy of germination of Chartolepis intermedia seeds, collected in the wild of Karaganda region, from morphology of seeds and conditions of cryopreservation is investigated. The maximum results for viability are fixed for dark-colored average or large seeds. The best results are determined for variant of cryopreservation in plastic container with future defrosting at the room temperature. For the increasing parameters of seed germination we recommended to freeze Chartolepis intermedia seeds with using cryoprotector sucrose in concentration 20%. As the results of the study, we developed algorithm of cryopreservation of Chartolepis intermedia seeds in liquid nitrogen.

scholarly journals Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion

2018 ◽  
Vol 14 ◽  
pp. 3018-3024
Author(s):  
Rudolf Knorr ◽  
Barbara Schmidt
Keyword(s):  
Michael Addition ◽  
Carbonyl Compounds ◽  
Room Temperature ◽  
Experimental Conditions ◽  
Metal Free ◽  
Metal Derivatives ◽  
Carbonyl Addition ◽  
Derivatives Of

Sterically well-shielded against unsolicited Michael addition and polymerization reactions, α-metalated α-(1,1,3,3-tetramethylindan-2-ylidene)acetonitriles added reversibly to three small aldehydes and two bulky ketones at room temperature. Experimental conditions were determined for transfer of the nucleofugal title carbanion unit between different carbonyl compounds. These readily occurring retro-additions via C–C(O) bond fission may also be used to generate different metal derivatives of the nucleofugal anions as equilibrium components. Fluoride-catalyzed, metal-free desilylation admitted carbonyl addition but blocked the retro-addition.

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