Factors Affecting Mosaic Distribution of Galls of an Eriophyid Mite, Eriophyes laevis, in Alder, Alnus glutinosa

Oikos ◽  
1989 ◽  
Vol 55 (3) ◽  
pp. 370 ◽  
Author(s):  
Timo Vuorisalo ◽  
Mari Walls ◽  
Pekka Niemelä ◽  
Heikki Kuitunen ◽  
Pekka Niemela
Keyword(s):  
Alnus Glutinosa ◽  
Factors Affecting ◽  
Eriophyid Mite ◽  
Mosaic Distribution

scholarly journals  Factors affecting the development of Phytophthora alni ssp. alni infections in Alnus glutinosa L.

2012 ◽  
Vol 58 (No. 3) ◽  
pp. 123-130 ◽  
Author(s):  
P. Štochlová ◽  
K. Novotná ◽  
K. Černý
Keyword(s):  
Resistance Breeding ◽  
Alnus Glutinosa ◽  
Potential Effect ◽  
Natural Resistance ◽  
Artificial Inoculation ◽  
Factors Affecting ◽  
Naturally Occurring ◽  
The Social ◽  
Resistant Genotypes ◽  
Active Disease

 Phytophthora alni is responsible for a devastating disease in alder and changes in the environment of riparian and alder carr ecosystems. One of the main approaches to solve this problem is to find naturally resistant genotypes using a series of artificial inoculation experiments, to preserve and use them in programmes for resistance breeding. However, the results of artificial inoculation experiments (screening for natural resistance) can be affected by several factors. The potential effect of the social status of the host, the presence of naturally occurring P. alni infections, the season and the size of the sections of branches used were studied in a series of infection experiments. It was found out that the development of lesions was significantly affected by the year season (the largest lesions were found in summer) and by the presence of naturally occurring P. alni infections in the sampled trees (the lesions were five times larger in healthy trees and trees recovered from natural P. alni infections compared to trees with active disease development).  

scholarly journals The second outbreak of the poplar leafminer Phyllonorycter populifoliella in St. Petersburg

2020 ◽  
pp. 81-94
Author(s):  
Н.А. Мамаев ◽  
Д.Д. Буй ◽  
А.В. Селиховкин
Keyword(s):  
Larval Mortality ◽  
Food Preferences ◽  
Population Characteristics ◽  
Mortality Factors ◽  
Factors Affecting ◽  
Leading Role ◽  
Role Of The State ◽  
Test Tree ◽  
History Of ◽  
Mosaic Distribution

Исследовались популяционные характеристики, факторы смертности и пищевые предпочтения минирующей листья тополя тополёвой нижнесторонней моли-пестрянки Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) в Санкт-Петербурге в связи с развитием второй в истории насаждений города вспышки массового размножения этого вредителя. В разных районах Санкт-Петербурга были заложены пробные площади с разной интенсивностью повреждения, варьирующей в среднем от 5,2 до 21,7 мин/лист. На каждой пробной площади в первые дни после начала лёта первого поколения (первая декада августа) срезались по две ветви в нижней части кроны с каждого дерева на которых анализировались мины 50 листьев для установления причин гибели и доли выживших особей. На всех пробных участках (за одним исключением) был один вид тополя - тополь берлинский Populus × berolinensis. Именно этот вид наиболее интенсивно повреждался Ph. populifoliella. Вспышка размножения в 2017-2019 гг., локализованная в Невском районе, постепенно распространяется по территории города, имея выраженный мозаичный характер,однако причины этой мозаичности распространения не ясны. Плотность популяции вредителя в Невском районе за последние годы существенно увеличилась. Наиболее успешно проходит развитие на деревьях с высокой плотностью популяции вредителя. С одного листа на таких участках вылетает 7 и более бабочек (36-52%) от начавших развиваться личинок), тогда как при меньшей плотности (в среднем 5 и 11 мин/лист) вылет составляет 8 и 19% соответственно. Это позволяет сделать предположение о ведущей роли состояния кормовых деревьев в развитии тополёвой моли. В отношении остальных факторов, влияющих на смертность, не удалось выявить их выраженного воздействия на плотность популяции. Population characteristics, mortality factors, and food preferences of the moth Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) mining leaves of poplar in St. Petersburg were studied under conditions of the second outbreak of this pest in the history of the urban plantings in St. Petersburg. In different districts of St. Petersburg, sample plots were established with different intensity of damage by the poplar leafminer, varying from 5.2 to 21.7 mines per leaf. On each sample plot, in the first days after the beginning of the flight of the first generation adults (the first ten days of August), two branches were cut in the lower part of the crown from each test tree, on which mines of at least 50 leaves were collected and analyzed to establish the causes of death and the proportion of the surviving individuals. With one exception, all sample plots were represented by one poplar species - the Berlin poplar Populus × berolinensis. This species was most intensively damaged by Ph. populifoliella . Outbreak in 2017- 2019 was initially localized in the Nevsky District and then gradually spread throughout the city, having the pronounced mosaic character, however, the reasons for the mosaic distribution of the outbreak are unclear. The density of the pest population has increased significantly in the Nevsky District over the past years. Development of the moth is most successful on trees with a high population density of the pest. Seven or more adult moths emerge from one leaf in such areas (36-52% of the larvae that begun to develop), while at a lower density (on average, 5-11 mines per leaf), the emergence was 8 and 19%, respectively. This finding allows us to assume the leading role of the state of forage trees in the development of the poplar leafminer. Contribution of the other factors affecting larval mortality was not possible to evaluate.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting

Speech Therapy Services in a Large School System: A Six-Year Overview

1976 ◽  
Vol 7 (4) ◽  
pp. 207-219 ◽  
Author(s):  
Constance P. DesRoches
Keyword(s):  
School System ◽  
Speech Therapy ◽  
Factors Affecting ◽  
Case Load ◽  
Number Of Children ◽  
School Population ◽  
System A ◽  
Therapy Services ◽  
And Shifts ◽  
Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

Assessing the Link Between Perception and Production in Cantonese Tone Acquisition

2019 ◽  
Vol 62 (5) ◽  
pp. 1243-1257 ◽  
Author(s):  
Peggy Pik Ki Mok ◽  
Holly Sze Ho Fung ◽  
Vivian Guo Li
Keyword(s):  
Language Acquisition ◽  
General Principle ◽  
Choice Task ◽  
Factors Affecting ◽  
Tone Pair ◽  
Tone Production ◽  
Monosyllabic Words ◽  
Early Production ◽  
Forced Choice Task ◽  
Production Accuracy

Purpose Previous studies showed early production precedes late perception in Cantonese tone acquisition, contrary to the general principle that perception precedes production in child language. How tone production and perception are linked in 1st language acquisition remains largely unknown. Our study revisited the acquisition of tone in Cantonese-speaking children, exploring the possible link between production and perception in 1st language acquisition. Method One hundred eleven Cantonese-speaking children aged between 2;0 and 6;0 (years;months) and 10 adolescent reference speakers participated in tone production and perception experiments. Production materials with 30 monosyllabic words were transcribed in filtered and unfiltered conditions by 2 native judges. Perception accuracy was based on a 2-alternative forced-choice task with pictures covering all possible tone pair contrasts. Results Children's accuracy of production and perception of all the 6 Cantonese tones was still not adultlike by age 6;0. Both production and perception accuracies matured with age. A weak positive link was found between the 2 accuracies. Mother's native language contributed to children's production accuracy. Conclusions Our findings show that production and perception abilities are associated in tone acquisition. Further study is needed to explore factors affecting production accuracy in children. Supplemental Material https://doi.org/10.23641/asha.7960826

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