Factors affecting the production of resting spores by Zoophthora radicans in the spotted alfalfa aphid, Therioaphis trifolii f. maculata

1989 ◽  
Vol 67 (3) ◽  
pp. 848-855 ◽  
Author(s):  
Travis R. Glare ◽  
Richard J. Milner ◽  
Graham A. Chilvers
Keyword(s):  
Indirect Evidence ◽  
Spore Production ◽  
Factors Affecting ◽  
Resting Spore ◽  
Solid Media ◽  
Number Of Factors ◽  
Resting Spores ◽  
Saturated Atmosphere ◽  
Zoophthora Radicans ◽  
Genetic Combination

Resting spore production by Zoophthora radicans (Brefeld) Batko in infected cadavers of the spotted alfalfa aphid, Therioaphis trifolii (Monell) f. maculata, varied according to a number of factors. For four isolates of the fungus tested, the proportion of cadavers containing resting spores was consistently greater at 10 °C than at higher temperatures. At 20 °C, a saturated atmosphere (100% RH) favoured resting spore production, and the proportion of infected cadavers that contained resting spores was nearly twice the amount of that at 95% RH. Individual isolates of the fungus were found to differ in their ability to form resting spores in infected cadavers; some formed resting spores in few or no cadavers, whereas others formed resting spores in many, under similar conditions. The ability to produce resting spores sometimes varied following serial culturing on solid media. Interestingly, resting spore production was found to correlate with inoculum density. Also, inoculation of aphids with two fungal isolates resulted in a marked increase in resting spore production compared with that of either isolate alone. It is presumed that some form of genetic combination is involved. Indirect evidence suggests that this is more likely to be cytoplasmic than nuclear in origin.

Formation and germination of resting spores from different strains from the Entomophthora muscae complex produced in Musca domestica

2001 ◽  
Vol 79 (9) ◽  
pp. 1076-1082 ◽  
Author(s):  
Lene Thomsen ◽  
José Bresciani ◽  
Jørgen Eilenberg
Keyword(s):  
Musca Domestica ◽  
House Fly ◽  
Spore Production ◽  
Spore Formation ◽  
Entomophthora Muscae ◽  
Resting Spore ◽  
Resting Spores ◽  
Group B ◽  
Different Strains

Three species within the Entomophthora muscae (Cohn) Fresenius complex (Entomophthora schizophorae Keller & Wilding, E. muscae s.str., and E. muscae "group B") were investigated for resting spore formation in vivo in the house fly (Musca domestica L.). Resting spores of E. muscae group B were experimentally induced from August to the beginning of February, while no resting spores were ever observed in E. schizophorae infected M. domestica or in flies infected by E. muscae s.str. originating from M. domestica. When newly dead fly cadavers containing E. muscae group B resting spores were kept moist, cystidia emerged from the abdomen; this is the first report of cystidia in the genus Entomophthora. Resting spore production was significantly affected by both temperature and E. muscae group B strain. More infected flies formed resting spores when kept 1 week at 10°C compared with constant exposure at 22°C, but the tendency of the different E. muscae group B strains to form resting spores persisted with shifting temperatures. After 4 months of incubation under natural winter conditions in Denmark, E. muscae group B resting spores germinated on water agar at 20°C with a 16 h light : 8 h dark photoperiod within 1 week, but no germ conidia were observed.Key words: Entomophthorales, Entomophthora muscae complex, Diptera, Musca domestica, resting spore formation, resting spore germination.

scholarly journals Abiotic and Biotic Factors Affecting Resting Spore Formation in the Mite PathogenNeozygites floridana

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Vanessa da Silveira Duarte ◽  
Karin Westrum ◽  
Ana Elizabete Lopes Ribeiro ◽  
Manoel Guedes Corrêa Gondim Junior ◽  
Ingeborg Klingen ◽  
...  
Keyword(s):  
Pathogenic Fungus ◽  
Field Studies ◽  
Spore Formation ◽  
Biotic Factors ◽  
Tetranychus Evansi ◽  
Tropical Regions ◽  
Factors Affecting ◽  
Resting Spore ◽  
Resting Spores ◽  
Abiotic And Biotic Factors

Neozygites floridanais an obligate mite pathogenic fungus in the Entomophthoromycota. It has been suggested that resting spores of this fungus are produced as a strategy to survive adverse conditions. In the present study, possible mechanisms involved in the regulation of resting spore formation were investigated in the hostsTetranychus urticaeandTetranychus evansi. Abiotic and biotic factors mimicking conditions that we, based on earlier field studies, thought might induce resting spores in temperate and tropical regions were tested with isolates from Norway and Brazil. A total of 42 combinations of conditions were tested, but only one induced the formation of a high number of resting spores in only one isolate. The Brazilian isolate ESALQ1420 produced a large number of resting spores (51.5%) inT. urticaeat a temperature of 11°C, photoperiod of 10L:14D, and light intensity of 42–46 (μmol m−2 s−1) on nonsenescent plants (nondiapausing females). Resting spores of the BrazilianN. floridanaisolate ESALQ1421 were found at very low levels (up to 1.0%). Small percentages ofT. urticaewith resting spores (0–5.0%) were found for the Norwegian isolate NCRI271/04 under the conditions tested. The percentages of resting spores found for the Norwegian isolate in our laboratory studies are similar to the prevalence reported in earlier field studies.

Impact of climatic conditions on the parameters of failure flow of military vehicles

2021 ◽  
pp. 095440702110202
Author(s):  
Nikolaj Dobrzinskij ◽  
Algimantas Fedaravicius ◽  
Kestutis Pilkauskas ◽  
Egidijus Slizys
Keyword(s):  
Climatic Factors ◽  
Armed Forces ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Technical Equipment ◽  
Factors Affecting ◽  
Military Vehicles ◽  
Equipment Reliability ◽  
Number Of Factors ◽  
The Impact

Relevance of the article is based on participation of armed forces in various operations and exercises, where reliability of machinery is one of the most important factors. Transportation of soldiers as well as completion of variety of tasks is ensured by properly functioning technical equipment. Reliability of military vehicles – armoured SISU E13TP Finnish built and HMMWV M1025 USA built were selected as the object of the article. Impact of climatic conditions on reliability of the vehicles exploited in southwestern part of the Atlantic continental forest area is researched by a case study of the vehicles exploitation under conditions of the climate of Lithuania. Reliability of military vehicles depends on a number of factors such as properties of the vehicles and external conditions of their operation. Their systems and mechanisms are influenced by a number of factors that cause different failures. Climatic conditions represent one of the factors of operating load which is directly dependent on the climate zone. Therefore, assessment of the reliability is started with the analysis of climatic factors affecting operating conditions of the vehicles. Relationship between the impact of climatic factors and failure flow of the vehicles is presented and discussed.

The life history of Plasmodiophora brassicae Woron

1972 ◽  
Vol 180 (1058) ◽  
pp. 103-112 ◽  
Keyword(s):  
Life History ◽  
Root Hair ◽  
Plasmodiophora Brassicae ◽  
Root Hairs ◽  
Secondary Phase ◽  
Tissue Cultures ◽  
Resting Spore ◽  
Resting Spores ◽  
Seedling Roots ◽  
History Of

Resting spore germination and the root hair stages of the life history of Plasmodiophora brassicae were studied in stained preparations of infected Brassica rapa seedling roots. Naked protoplasts, usually possessing two unequal flagella, were released from resting spores through a small circular pore. They penetrated the root hairs of B. rapa and there developed into plasmodia which, after becoming multinucleate, cleaved to form zoosporangia con­taining incipient zoospores. Biflagellate zoospores were released from root hair zoosporangia and fused in pairs, although karyogamy did not occur. The resulting binucleate zoospores infected the cortical dells of B. rapa to form binucleate plasmodia, the earliest stages of the secondary phase of the life history. These findings are discussed in relation to previous studies on the life history of P. brassicae in Brassica plants and in Brassica tissue cultures, and a new complete life history, including nuclear fusion in the secondary plasmodium, is suggested for the organism.

Implementation of Machine Learning Algorithms for Prediction of Fluidelastic Instability in Tube Arrays

2021 ◽  
Vol 143 (2) ◽  
Author(s):  
Joaquin E. Moran ◽  
Yasser Selima
Keyword(s):  
Machine Learning ◽  
Logistic Regression ◽  
Learning Algorithm ◽  
Machine Learning Algorithms ◽  
Two Phase ◽  
Factors Affecting ◽  
Logistic Regression Models ◽  
Number Of Factors ◽  
Tube Arrays ◽  
Fluidelastic Instability

Abstract Fluidelastic instability (FEI) in tube arrays has been studied extensively experimentally and theoretically for the last 50 years, due to its potential to cause significant damage in short periods. Incidents similar to those observed at San Onofre Nuclear Generating Station indicate that the problem is not yet fully understood, probably due to the large number of factors affecting the phenomenon. In this study, a new approach for the analysis and interpretation of FEI data using machine learning (ML) algorithms is explored. FEI data for both single and two-phase flows have been collected from the literature and utilized for training a machine learning algorithm in order to either provide estimates of the reduced velocity (single and two-phase) or indicate if the bundle is stable or unstable under certain conditions (two-phase). The analysis included the use of logistic regression as a classification algorithm for two-phase flow problems to determine if specific conditions produce a stable or unstable response. The results of this study provide some insight into the capability and potential of logistic regression models to analyze FEI if appropriate quantities of experimental data are available.

PORTFOLIO ANALYSIS IN THE DEVELOPMENT OF CORPORATE STRATEGY

2021 ◽  
Vol 2 (10) ◽  
pp. 13-20
Author(s):  
Ekaterina A. Egorova ◽  
◽  
Polina V. Syrovatkina ◽  
Tatiana F. Chernova ◽  
Irina S. Brikoshina ◽  
...  
Keyword(s):  
Strategic Management ◽  
Corporate Strategy ◽  
Portfolio Analysis ◽  
Point Of View ◽  
Factors Affecting ◽  
Number Of Factors ◽  
Market Situation

This article reveals the specifics of developing a corporate strategy using portfolio analysis, taking into account the current market situation, which has created a number of factors affecting labor produc-tivity, internal and external policies of organizations, using the example of the work of the "Vishnevii sad" theater. The information about portfolio analysis in the development of corporate strategy is presented from the point of view of strategic management. Both theoretical and practical data are given, including different ways of constructing portfolio analysis, rules and methods that can be implemented. Proposals for modifica-tion and improvement of internal processes taking into account the influence of extraneous factors, possible goals and results are presented.

scholarly journals Motivating factors affecting the individual energy consumption behavior

2021 ◽  
Vol 124 ◽  
pp. 08003
Author(s):  
Jalal ud Din Akbar ◽  
Muhammad Ridhuan Tony Lim Abdullah
Keyword(s):  
Climate Change ◽  
Energy Consumption ◽  
Human Behavior ◽  
Clean Energy ◽  
Daily Routine ◽  
Factors Affecting ◽  
Number Of Factors ◽  
Development Goals ◽  
The Government ◽  
The Individual

Global challenges of climate change and environmental deterioration helped in formulating seventeen sustainable development goals through United Nation. Achieving these sustainable goals, Malaysia initiated and track progress towards affordable and clean energy. The natural environment and climate are mostly influenced by human behavior. Due to the role of human behavior in climate change, a strong tendency towards the pursuit of energy sustainability exists. Attention is paid to strengthen the human behavior from general acts of doing things to carrying specific actions by adopting a responsible behavior into daily routine. A number of factors were identified through literature such as social structure, institution, and education for understanding the individual behavior for sustainability with regard to energy consumption. Many experts related to the field of energy were engaged to sort and prioritize these factors with respect to their importance by using multi-criteria decision making tool of analytical hierarchy process (AHP). The experts were selected from different sectors such as academia, NGOs and industry. With the help of experts, a framework of individual energy consumption behaviour is developed to allow the government and other stakeholders to make policies accordingly to achieve energy sustainable.

Cultural Factors Affecting Integration of Technology in Media Education in Nigeria

2014 ◽  
pp. 63-76
Author(s):  
Ofomegbe Daniel Ekhareafo ◽  
Oroboh Ambrose Uchenunu
Keyword(s):  
Information And Communication Technologies ◽  
Information Age ◽  
Communication Technologies ◽  
Cultural Factors ◽  
Media Education ◽  
Factors Affecting ◽  
Number Of Factors ◽  
Integration Of Technology ◽  
Information And Communication ◽  
Technological World

Today's world is aptly described as an information age, driven primarily by Information and Communication Technologies. This chapter stresses the idea that ICT usage in media education will not only improve the capacity of the students to learn but also improve the capacity of the facilitators. Although there are a number of factors that affect the integration of technology in learning, the chapter advocates that against the benefit of ICT education proactive steps need to be taken to redress the low trend if the graduates must compete with others, particularly those with overseas qualifications and other professionals in today's globalised and evanescent technological world.

scholarly journals The analysis of atmospheric factors affecting the value of vertical refraction angle with the assessment of the importance of introduction of the atmospheric amendment

2018 ◽  
Vol 71 ◽  
pp. 00019
Author(s):  
Paulina Kaczor
Keyword(s):  
Laser Beam ◽  
Atmospheric Correction ◽  
Refraction Angle ◽  
Factors Affecting ◽  
Number Of Factors ◽  
Four Seasons ◽  
Vertical Displacements ◽  
Opencast Mines ◽  
Atmosphere Density ◽  
Atmospheric Factors

The study of vertical displacements of hydrotechnical objects, slender constructions, opencast mines or flotation waste reservoirs often requires continuous geodetic monitoring, which in real time defines potential threats resulting from changes in the geometry of the object. In order to ensure high accuracy in determining vertical displacements, a precise robotic tacheometer is used as one of the monitoring sensors. In the case of trigonometric leveling, the quality of measurements is affected not only by the accuracy of the instrument, but also by the centre through which the laser beam emitted by it passes. The radius emitted by the tacheometer due to the layered structure of the atmosphere is deflected, and the angle that it creates with the theoretical course of rays is called the angle of vertical refraction. In order to eliminate the influence of this type of errors, so-called atmospheric correction is introduced to all tacheometric measurements. Currently, total stations automatically determine and introduce corrections for observation, usually using only air temperature and atmospheric pressure. However, the number of factors responsible for the change in atmosphere density, and thus the deflection of the laser beam is much greater. And its influence is also affected by the length of the target and roughness of the area over which the measurement is made. The paper presents the analysis of the significance of various atmospheric and terrain factors that may affect the value of the vertical refraction angle. By the multiple regression method, with the use of the analyzed factors, equations describing the phenomenon of vertical refraction for four seasons have been designated. The defined equation coefficients were used to determine the refraction angle for the observations recorded on the post-flotation waste tank. To confirm the rightness of introducing an additional atmospheric correction, analyses were performed showing the percentage of corrected results.

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