scholarly journals Leucotelium cerasi (Bérenger) Tranzschel 1935, novel pathogen for mycobiota in Serbia

2020 ◽  
pp. 29-38
Author(s):  
Stefan Bogosavljevic ◽  
Milos Stupar ◽  
Milica Ljaljevic-Grbic ◽  
Jelena Vukojevic
Keyword(s):  
Host Species ◽  
Natural Populations ◽  
Field Studies ◽  
Parasitic Fungus ◽  
Prunus Species ◽  
Protection Measures ◽  
Foliar Tissue ◽  
High Degree ◽  
Number Of Individuals ◽  
Very High

During the field studies on a strictly protected plant species Eranthis hyemalis (winter aconite) in Serbia, it was noticed that certain individuals were infected by some species of parasitic fungus. According to the structure of spermogonia and aecia, as well as distinctive types of spores recorded in infected leaves of winter aconite, the fungus was determined as Leucotelium cerasi, known as a causative agent of rust in E. hyemalis and Prunus species. Although it was first recorded in Serbia in Prunus spinosa as a host (area of Valjevo in 1935), the appearance of this phytopathogen was recorded in foliar tissue of E. hyemalis at four localities in Eastern Serbia, near Knjazevac (Podvis, Golemi Kamen, and Ploca) and Zajecar (Zmijanac). It was concluded that plants in natural populations of host species were infected to a very high degree, as the number of infected plants reached half of the total number of individuals in all studied populations. Further research is neces?sary to determine to what extent this fungus is threatening the survival of host populations and then implement appropriate protection measures.

Impact de la sélection sur la variabilité génétique de l'épinette blanche au Québec

1993 ◽  
Vol 23 (6) ◽  
pp. 1196-1202 ◽  
Author(s):  
Mireille Desponts ◽  
Ariane Plourde ◽  
Jean Beaulieu ◽  
Gaétan Daoust
Keyword(s):  
Genetic Structure ◽  
Natural Populations ◽  
Diallel Cross ◽  
Significant Loss ◽  
Enzymatic Systems ◽  
Old Trees ◽  
Number Of Individuals ◽  
Very High ◽  
Sizeable Reduction ◽  
Selection Of

The genetic structure and variability of two natural white spruce (Piceaglauca (Moench) Voss.) populations from southern Quebec were compared by isoenzymatic analysis with those observed from three superior provenances of the Great Lakes and St. Lawrence regions. Twenty 15- to 20-year-old trees, selected within the provenances and integrated into a diallel cross plan, were also studied. The analysis of seven enzymatic systems demonstrates, in an overall fashion, the consistency of variability within provenances when these are compared with natural populations. It indicates that the selection of a restricted number of individuals in these populations does not cause a significant loss of variability. The level of heterozygosity for the selected individuals integrated into the diallel cross plan appears very high and no loss of alleles is recorded when compared with the original provenances, despite the sizeable reduction in numbers. This result suggests that the second selection, in favour of individuals demonstrating a strengthened vigour, favored the most polymorph genotypes.

Electron Microscopy in Molecular Biology

1967 ◽  
Vol 25 ◽  
pp. 2-3
Author(s):  
Cecil E. Hall
Keyword(s):  
Electron Microscopy ◽  
Molecular Biology ◽  
Noise Level ◽  
Molecular Structures ◽  
Material Structure ◽  
The Arts ◽  
Shadow Casting ◽  
Electron Image ◽  
High Degree ◽  
Very High

The visualization of organic macromolecules such as proteins, nucleic acids, viruses and virus components has reached its high degree of effectiveness owing to refinements and reliability of instruments and to the invention of methods for enhancing the structure of these materials within the electron image. The latter techniques have been most important because what can be seen depends upon the molecular and atomic character of the object as modified which is rarely evident in the pristine material. Structure may thus be displayed by the arts of positive and negative staining, shadow casting, replication and other techniques. Enhancement of contrast, which delineates bounds of isolated macromolecules has been effected progressively over the years as illustrated in Figs. 1, 2, 3 and 4 by these methods. We now look to the future wondering what other visions are waiting to be seen. The instrument designers will need to exact from the arts of fabrication the performance that theory has prescribed as well as methods for phase and interference contrast with explorations of the potentialities of very high and very low voltages. Chemistry must play an increasingly important part in future progress by providing specific stain molecules of high visibility, substrates of vanishing “noise” level and means for preservation of molecular structures that usually exist in a solvated condition.

A Low-Noise, High-Gain Quasi-Millimeter-Wave Receiver MMIC with a Very High Degree of Integration Using 3D-MMIC Technology

2011 ◽  
Vol E94-C (10) ◽  
pp. 1548-1556 ◽  
Author(s):  
Takana KAHO ◽  
Yo YAMAGUCHI ◽  
Kazuhiro UEHARA ◽  
Kiyomichi ARAKI
Keyword(s):  
Millimeter Wave ◽  
High Gain ◽  
Low Noise ◽  
High Degree ◽  
Very High ◽  
Millimeter Wave Receiver

scholarly journals Vegetation Diversity of Screes and Taluses of The Pamir and South-Western Tian Shan in Middle Asia

2021 ◽  
Author(s):  
Arkadiusz Nowak ◽  
Sebastian Świerszcz ◽  
Sylwia Nowak ◽  
Marcin Nobis
Keyword(s):  
Species Composition ◽  
Arid Zone ◽  
Field Studies ◽  
Vegetation Diversity ◽  
Plant Associations ◽  
Middle Asia ◽  
Recent Developments ◽  
Phytosociological Relevés ◽  
High Degree ◽  
Tian Shan

AbstractThis paper presents the results of phytosociological research on scree vegetation of the Pamir and south-western Tian Shan. We collected 222 phytosociological relevés during field studies conducted in 2015–2019, applying the Braun-Blanquet approach. We identified 21 plant communities on mobile and stabilized screes of colluvial cones, aprons and fans, inhabiting mainly the montane and alpine belts in several ranges (e.g. Peter the First, Alichur, Shugnan, Shachdarian, Darvaz, Rushan, Vanch, Fergana, Kyrgyz and Terskey ranges). As a result we provide the first comprehensive hierarchical syntaxonomic synopsis of scree communities at montane and alpine elevations in the eastern Middle Asia. The collected vegetation relevés represent the majority of the variation among the phytocoenoses of gravel, pebble, cobble and rock block slides and screes in the montane and alpine belts. As a result of field studies and Twinspan analyses, nine associations were identified on screes of the Pamir and western Tian Shan. All these communities were assigned to the Sileno brahuicae-Lactucetalia orientalis Nowak et al. 2021. Additionally, within the nitrophilous compact gravel screes one subassociation of Corydalidetum kashgaricae trigonelletosum gontscharovii was distinguished. In the most arid zone two additional plant associations and one subassociation were identified in gravelly semi-deserts zone. The main factors determining the species composition of the studied associations are scree mobility, rock particle size, elevation above sea level and slope inclination. Our research revealed considerable diversity of scree habitats of montane and alpine belts what might be astonishing regarding harsh environment of this mountainous territory. However, a great number of lineages that evolved here and particularly rich species pool of this habitat in Middle Asia facilitate remarkable diversity among vegetation of taluses and screes. The distinctiveness of species composition is additionally enhanced by high degree of endemism of chasmophytic habitats in the eastern part of Middle Asia. Despite recent developments, the prominent chasmophytic vegetation of Middle Asia still needs thorough studies focused on its relationship to semi-desert, tall-forb and petrophytic communities of high mountains of the Pamir, Hindu-Kush, Kunlun and Central Tian Shan.

scholarly journals Multi-Locus Selection and the Structure of Variation at the white Gene of Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 635-645 ◽  
Author(s):  
David A Kirby ◽  
Wolfgang Stephan
Keyword(s):  
Drosophila Melanogaster ◽  
White Gene ◽  
Transcriptional Unit ◽  
North American Population ◽  
Evolutionary Mechanisms ◽  
Locus Selection ◽  
Neutral Equilibrium ◽  
History Of ◽  
High Degree ◽  
Very High

Abstract We surveyed sequence variation and divergence for the entire 5972-bp transcriptional unit of the white gene in 15 lines of Drosophila melanogaster and one line of D. simulans. We found a very high degree of haplotypic structuring for the polymorphisms in the 3′ half of the gene, as opposed to the polymorphisms in the 5′ half. To determine the evolutionary mechanisms responsible for this pattern, we sequenced a 1612-bp segment of the white gene from an additional 33 lines of D. melanogaster from a European and a North American population. This 1612-bp segment encompasses an 834bp region of the white gene in which the polymorphisms form high frequency haplotypes that cannot be explained by a neutral equilibrium model of molecular evolution. The small number of recombinants in the 834bp region suggests epistatic selection as the cause of the haplotypic structuring, while an investigation of nucleotide diversity supports a directional selection hypothesis. A multi-locus selection model that combines features from both-hypotheses and takes the recent history of D. melanogaster into account may be the best explanation for these data.

Anomalies: The Winner's Curse

1988 ◽  
Vol 2 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Richard H Thaler
Keyword(s):  
Field Studies ◽  
Risk Averse ◽  
Common Phenomenon ◽  
Winner's Curse ◽  
Winner’S Curse ◽  
Empirical Question ◽  
Common Value ◽  
Winning Bidder ◽  
Common Value Auction ◽  
Very High

Next time that you find yourself a little short of cash for lunch, try the following experiment in your class. Take a jar and fill it with coins, noting the total value of the coins. Now auction off the jar to your class (offering to pay the winning bidder in bills to control for penny aversion). Chances are very high that the following results will be obtained: (1) the average bid will be significantly less than the value of the coins (bidders are risk averse); (2) the winning bid will exceed the value of the jar. Therefore, you will have money for lunch, and your students will have learned first-hand about the “winner's curse.” The winner's curse cannot occur if all the bidders are rational, so evidence of a winner's curse in market settings would constitute an anomaly. However, acting rationally in a common value auction can be difficult. Solving for the optimal bid is not trivial. Thus, it is an empirical question whether bidders in various contexts get it right or are cursed. I will present some evidence, both from experimental and field studies, suggesting that the winner's curse may be a common phenomenon.

Implications of phenotypic plasticity for numerical taxonomy of Ornithogalum montanum (Liliaceae)

1991 ◽  
Vol 69 (1) ◽  
pp. 34-38 ◽  
Author(s):  
M. Pigliucci ◽  
M. G. Politi ◽  
D. Bellincampi
Keyword(s):  
Principal Component Analysis ◽  
Phenotypic Plasticity ◽  
Numerical Taxonomy ◽  
Natural Populations ◽  
Principal Component ◽  
Reaction Norm ◽  
Component Analysis ◽  
Morphological Response ◽  
Numerical Taxonomic Study ◽  
High Degree

Implications of phenotypic plasticity in a subspecific numerical taxonomic study of Ornithogalum montanum Cyr. (Liliaceae) are discussed. Clones belonging to six natural populations were grown in a glasshouse, and their morphological response to three water dosages was analyzed by means of principal component analysis. PC-1 ranks the three groups of replicated populations, suggesting a high degree of phenotypic plasticity; on the other hand, PC-3 is almost environmentally independent. Proximities in the phenetic space are shown to be at least partially environmentally dependent, suggesting a reaction norm for the character correlation matrix. The results do not corroborate a previous recognition of six subspecies of O. montanum. Key words: phenotypic plasticity, numerical taxonomy, Ornithogalum, reaction norm, principal component analysis.

Continuous DNA replication in the nucleus of the dinoflagellate Prorocentrum micans (Ehrenberg)

1977 ◽  
Vol 27 (1) ◽  
pp. 81-90
Author(s):  
S.A. Filfilan ◽  
D.C. Sigee
Keyword(s):  
Electron Microscope ◽  
Dna Synthesis ◽  
Nuclear Dna ◽  
Continuous Process ◽  
Prorocentrum Micans ◽  
Interphase Nuclei ◽  
Electron Microscope Autoradiography ◽  
Dividing Cells ◽  
High Degree ◽  
Very High

The uptake of tritiated thymine into cells of a heterogeneous population of Prorocentrum micans was investigated using light-microscope and electron-microscope autoradiography. Specificity of thymine uptake into DNA was demonstrated by the specific removal of label from wax-embedded material using DNase and by the high degree of localization of nuclear label to chromosomes in the electron-microscope autoradiographs. All nuclei, including both dividing and non-dividing cells, showed a substantial uptake of label, indicating that nuclear DNA synthesis in Prorocentrum micans is a continuous process. The level of DNA synthesis does show considerable variation, however, with very high levels in some interphase nuclei. The continuous replication of nuclear DNA provides further evidence of dinoflagellate affinity to the prokaryotes, and indicates that Prorocentrum micans is a very primitive eukaryote cell.

Decision Support System Based on Fuzzy Logic for Assessment of Expected Corporate Income Performance

2021 ◽  
pp. 2150009
Author(s):  
Arthur Yosef ◽  
Eli Shnaider ◽  
Rimona Palas ◽  
Amos Baranes
Keyword(s):  
Fuzzy Logic ◽  
Decision Support ◽  
Operating Income ◽  
Explanatory Variables ◽  
Section Model ◽  
Evaluation Mechanism ◽  
One Year ◽  
High Degree ◽  
Decision Support Method ◽  
Very High

This study presents a decision-support method to estimate the next year performance of corporate Operating Income Margin (OIM). It is based on a unique combination of cross-section model and the rules-based evaluation mechanism. The estimate is done in terms of broad categories, and not precise numerical values. The model is constructed as follows: its dependent variable (OIM) is one year ahead vs. the corresponding explanatory variables. This structure of the model allows us to view explanatory variables as reflecting financial potential of corporations. The evaluation component consists of a set of rules designed to identify the companies whose “potential” clearly points to an opportunity to invest. For the method presented here to succeed, it is necessary to utilize a highly reliable modeling method, even if it is “Fuzzy”. We apply Soft Regression (SR), which is a Soft Computing modeling tool based on Fuzzy Logic, and utilize all available proxy variables by creating intervals of values. Advantages of utilizing SR, and the intervals’-based modeling are extensively discussed. Modeling results for five consecutive years are consistent and stable, thus indicating high degree of reliability. Testing indicates very high success rate for the stock market related domain, the lowest being 87.9%.

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