scholarly journals Aspects of the methodology of plant populations research (by means of the example of rare species)

2020 ◽  
pp. 115-128
Author(s):  
Volodymyr Kyyak ◽  
Andriy Malynovskyі
Keyword(s):  
Research Methodology ◽  
Rare Species ◽  
Vegetative Reproduction ◽  
Integral Characteristic ◽  
Life Forms ◽  
Population Based ◽  
Population Diversity ◽  
Isolated Populations ◽  
Long Time ◽  
Dynamic Endurance

In this work basic concepts and problematic issues of modern population ecology of plants are considered. Quite different views on many aspects of terminology and research methodology one can observed in the scientific literature. Basic terms such as: «vitality», «age structure», «ontogenetic structure», «self-renewal», «strategy», «regeneration niche», «buffering», population size establishment, etc can be interpreted differently, which causes significant discrepancies in research methodology, and thus are reflected in the interpretation of results. The population is considered as an indivisible and unique set of individuals of one species, which is characterized by self-reproduction while maintaining its main properties. The statemen concerning the population as a unit of biodiversity accountability is justified. The study of strategy, intra-population diversity, viability and mechanisms of self-recovery has shown that the existence of populations for a long time is ensured by a certain structure. The structure of the population is a set of quantitative and qualitative components of its organization at the individual and group level, which characterize the structure and ensure the functioning of the population as a whole system. At the same time, establishing which structural elements play a leading role in the changed environmental conditions continues to be an urgent task for species of different life forms in the variety of conditions of their habitats. The example of isolated populations of rare species shows the most typical stages of structure change due to pessimization of living conditions: simplification of spatial structure, aging or pseudo-rejuvenation, reduction of vitality of individuals and population loci, reduction of self-sufficiency and reproduction, simplification and reduction of ontogenesis of individuals, predominance of death rate over birth rate, reduction of area, number and density, cessation of formation of generative individuals, cessation of undergrowth replenishment, reduction of vegetative reproduction, loss of population viability. An integral characteristic that reflects the current state of the population based on the most important individual and group parameters of structure, growth, development and reproduction is the vitality of the population. Intrapopulation structural components - population loci of reproduction - are of the greatest importance in preserving the viability of populations and ensuring the prospects of their existence in the event of adverse changes in the environment. Among population structures, the highest dynamic endurance and stability of functioning for a long time under different conditions of natural and anthropogenically altered environment were found in metapopulations. Understanding of the processes taking place on the verge of existence of the population during its emergence, and especially during the period of its loss of viability and extinction, is extremely important. However, there are still not so many researches aimed at revealing the patterns of behavior of populations during these most vulnerable periods of their long life cycle.

The role of seed reproduction in the dynamics of established populations of Hieracium floribundum and a comparison with that of vegetative reproduction

1975 ◽  
Vol 53 (24) ◽  
pp. 3022-3031 ◽  
Author(s):  
A. G. Thomas ◽  
H. M. Dale
Keyword(s):  
Population Dynamics ◽  
Seedling Establishment ◽  
Vegetative Reproduction ◽  
Soil Surface ◽  
Growing Season ◽  
Population Based ◽  
Early Spring ◽  
Viable Seed ◽  
Density Patch

In the crowded parts of patches of Hieracium floribundum Wimm. and Grab., which were established for at least a decade in an ungrazed pasture, 7–10% of the population (3700 individuals/m2) flowered. Of the plants that flowered, 94% were alive a year later, but only 5% of these flowered. Abortion of flower heads was common; one half of all those which were initiated in early June had aborted by flowering time in early July. Freshly dispersed seed had a viability of 57%, which was reduced to 17% a year later, after its storage close to the soil surface. Less than 6% of the viable seed was innately dormant. Dry, laboratory-stored seed retained its viability for the year but was slower to germinate than soil-stored seed. In field conditions, germination was temperature inhibited during most of the growing season. Maximum daytime microsite temperatures of less than 32 °C, which is necessary for germination, were found to occur only in early spring and late fall. Successful seedling establishment accounts for 1% of the individuals in a crowded population. Based on the maximum sexual reproduction from plants in crowded populations, a seed has a probability of 1 in 20 000 of becoming an established seedling. A model of population dynamics in a high-density patch traces the fate of seedling establishment, surviving adults, and stolon-derived rosettes for a single year.

scholarly journals Skeletal polymorphism and genetic drift in a Delhi frog, Rana cyanophlictis – a follow-up study

1978 ◽  
Vol 31 (2) ◽  
pp. 103-106 ◽  
Author(s):  
Manjit Singh Grewal
Keyword(s):  
Genetic Drift ◽  
Environmental Conditions ◽  
Population Diversity ◽  
Isolated Populations ◽  
Follow Up Study

SUMMARYFour isolated populations of the skipper frog, Rana cyanophlictis were first studied in 1965 and then again in 1975. The genetical changes were measured by the incidence of 19 non-metrical skeletal variants. It was found that these populations have changed very little in 10 years, although the inter-population diversity, as judged by the estimates of divergence, is less now than previously. This could be due to the similar environmental conditions prevailing in Delhi and its neighbourhood from where these frog populations were collected.

scholarly journals An Improved Harmony Search Based on Teaching-Learning Strategy for Unconstrained Optimization Problems

2013 ◽  
Vol 2013 ◽  
pp. 1-29 ◽  
Author(s):  
Shouheng Tuo ◽  
Longquan Yong ◽  
Tao Zhou
Keyword(s):  
High Dimension ◽  
Learning Strategy ◽  
Optimization Problems ◽  
Search Algorithm ◽  
Harmony Search ◽  
Population Based ◽  
Population Diversity ◽  
Random Mutation ◽  
Complex Optimization ◽  
Teaching Learning

Harmony search (HS) algorithm is an emerging population-based metaheuristic algorithm, which is inspired by the music improvisation process. The HS method has been developed rapidly and applied widely during the past decade. In this paper, an improved global harmony search algorithm, named harmony search based on teaching-learning (HSTL), is presented for high dimension complex optimization problems. In HSTL algorithm, four strategies (harmony memory consideration, teaching-learning strategy, local pitch adjusting, and random mutation) are employed to maintain the proper balance between convergence and population diversity, and dynamic strategy is adopted to change the parameters. The proposed HSTL algorithm is investigated and compared with three other state-of-the-art HS optimization algorithms. Furthermore, to demonstrate the robustness and convergence, the success rate and convergence analysis is also studied. The experimental results of 31 complex benchmark functions demonstrate that the HSTL method has strong convergence and robustness and has better balance capacity of space exploration and local exploitation on high dimension complex optimization problems.

scholarly journals The Principles of Life

2020 ◽  
Author(s):  
Diogo Gonçalves
Keyword(s):  
Metabolic Flux ◽  
Life Forms ◽  
Theoretical Framework ◽  
Living Systems ◽  
Complete Understanding ◽  
Chemical Systems ◽  
Terrestrial Life ◽  
Long Time ◽  
Definition Of ◽  
The Doors

The questions of what life is and how it first started have for a long-time daunted science. Our rather small understanding of what living systems are is demonstrated by the inexistence of a widely accepted chemical definition of them. This work intends to solve this long-lasting problem by laying such a definition as well as the principles that have governed living systems since their inception up to their extant forms. Here I show that living entities are productive chemical systems that bias their own formation. It will be shown that these two aspects inevitably lead to a selection by the highest replicative metabolic flux, explaining all the characteristics of extant living systems, where the strength of the biasing effect can be considered the main difference between life now, and at its origin. By building a narrative on how such a journey may have taken place, this work intends to provide the theoretical framework and experimental inspiration for a complete understanding of evolution, simultaneously creating new avenues to the search for extra-terrestrial life forms and opening the doors to the development of living technologies.

scholarly journals New locations of rare species in the flora of the Kabardino-Balkar Republic

2020 ◽  
Vol 19 (2) ◽  
pp. 394-399
Author(s):  
V. A. Chadaeva ◽  
N. L. Tsepkova ◽  
R. Kh. Pshegusov ◽  
A. V. Kolchenko ◽  
A. Zh. Zhashuev ◽  
...  
Keyword(s):  
Rare Species ◽  
Vascular Plant ◽  
Habitat Preferences ◽  
Taxus Baccata ◽  
Isolated Populations ◽  
Native Flora ◽  
Eriophorum Angustifolium ◽  
Red Data Book ◽  
New Locations ◽  
Data Book

Various types of forest and meadow plant communities of the Kabardino-Balkar Republic (CentralCaucasus) from the steppes to the alpine were examined by the route method during floristic investigations in 2018–2019. New locations of five rare species of vascular plants of the region natural flora were found (Picea orientalis (L.)Peterm., Taxus baccata L., Betula raddeana Trautv., Acer trautvetteri Medw., Eriophorum angustifolium Honck.). Exactlocations for another five rare species within the previously designated areas were also identified (Pojarkovia pojarkovae(Schischk.) Greuter., Scopolia carniolica Jacq., Hypericum nummularioides Trautv., Securigera orientalis(Mill.) Lassen,Galanthus alpinus Sosn.). The article presents the data on the floristic finds, indicating the coordinates of specific locations,species habitat preferences in region, the number of populations, the species distribution in the Caucasus, and informationof inclusion in the Red Books of adjacent regions. The rarest vascular plant species for the native flora of the KabardinoBalkar Republic are Galanthus alpinus, Scopolia carniolica, Pojarkovia pojarkovae. All three species were revealed inmountain territories subject to high recreational (trampling by tourists, picking up flowers) and economic (grazing) loads.All three species were revealed in mountain territories. The findings of isolated populations of Picea orientalis, Taxus baccata, Betula raddeana, Acer trautvetteri provided new information about the distribution and ecology of these rarespecies listed in the latest edition of regional Red Data Book. For these species, the categories of rarity status acceptedin the Red Book of the Kabardino-Balkar Republic are confirmed. Galanthus alpinus, Scopolia carniolica, Pojarkoviapojarkovae, Hypericum nummularioides, Securigera orientalis, Eriophorum angustifolium are proposed for inclusion inthe next edition of the Kabardino-Balkar Red Data Book. The most endangered state was identified for Picea orientalis,for which only two habitats in the region are reliably known and those are subject to intense anthropogenic impact.

scholarly journals Current State of Populations of Rhodiola Rosea L. (Crassulaceae) in East Kazakhstan

2021 ◽  
Author(s):  
Serik Kubentayev ◽  
Moldir Zhumagul ◽  
Meruyert Kurmanbayeva ◽  
Daniar Alibekov ◽  
Juri Kotuhov Kotuhov ◽  
...  
Keyword(s):  
Plant Community ◽  
Vegetative Reproduction ◽  
Analysis Data ◽  
Life Forms ◽  
Extreme Conditions ◽  
Ecological Groups ◽  
Systematic Analysis ◽  
Current State ◽  
Age Related ◽  
Rare And Endangered

Abstract Background: Based on world experience, first, a modern assessment of the flora is needed to develop strategies and tactics for the conservation of ecosystems of rare and endangered plant species. A regional and global biodiversity strategy should focus on assessing the current state of bioresources. In this regard, to preserve the biodiversity, the botanical features, the ontogenetic state, the ecological and phytocenotic structure of the rare endangered species Rh. rosea in the highlands of Eastern Kazakhstan were studied.Results: Ten populations of Rh. rosea were identified under various ecological and geomorphological conditions with a detailed description of the structure of the plant community. Systematic analysis of the plant community with Rh. rosea shows that the families Poaceae Barnhart, Ranunculaceae Juss., Asteraceae Bercht, J. Presl, Rosaceae Juss. and the leaders in the number of species are Caryophyllaceae Juss., Apiaceae Lindl., Fabaceae Lindl., Polygonaceae Juss. They make up 97 (69%) of the species in the plant community. Ecological analysis data show that the plant community is dominated by psychrophytes (32%), mesophytes (28%), mesopsychrophytes (11%) and mesoxerophytes (7%). Chorological analysis of plant populations with rh factor. rosea indicates that the Asian group (39%), the Eurasian group (30%), and the Holarctic group (20%) are the most widely represented. In Rh. rosea populations, it is most often found with Schulzia crinita, Achillea ledebourii, Doronicum altaicum, Macropodium nivale, Hylotelephium telephium, Rhodiola algida, Carex capillaris, C. aterrima, C. stenocarpa, Euphorbia pilosa, Trifolium lupinast. In the ontogenesis of Rh. rosea, all age-related conditions were identified, with the exception of the prussic condition, and the life expectancy is 50-55 years.Conclusions: The state of Rh. rosea populations is assessed as satisfactory, capable of self-sufficiency mainly due to vegetative reproduction. Seed renewal is low as a result of seedling death in the early stages of development due to extreme habitat conditions. In communities with Rh. rosea, one - and two-species families predominate, which indicates the complexity of the process of florogenesis in extreme conditions of existence. In general, the distribution of life forms, ecological groups, and species composition of communities with Rh. the participation of the rose is natural for extreme conditions of existence.

scholarly journals The dynamics of Listera ovata populations on mineral islands in the Biebrza National Park

2014 ◽  
Vol 71 (3) ◽  
pp. 243-251 ◽  
Author(s):  
Emilia Brzosko
Keyword(s):  
Population Dynamics ◽  
National Park ◽  
Vegetative Reproduction ◽  
Leaf Size ◽  
The Other ◽  
Costs Of Reproduction ◽  
Isolated Populations ◽  
Other Hand ◽  
Population Sizes

Observations of two isolated populations of <em>Listera ovata</em> (Oparzelisko and Zabudnik) were conducted for 7 years in the Biebrza National Park. The studied populations differed in size, proportion of flowering individuals and effectiveness of reproduction. High number of juvenile individuals in OPA population was noted under conditions more favourable for germination (gaps in vegetation and higher moisture of soil). On the other hand, vegetative reproduction is important in the dynamics of ZAB population. The natural fruiting rate of <em>L. ovata</em> is relatively high (up to 90%) and does not seem to be pollinator limited. Some costs of reproduction especially in terms of leaf size were observed. The dormancy is important in the population dynamics. In some years even one third of the population may be dormant. <em>L. ovata</em> produces enough seeds and offspring to maintain or even increase population sizes. These facts, connected with the longevity of individuals,indicate that populations of <em>L. ovata</em> in the Biebrza National Park are not threatened with extinction in the nearest future.

High-Order Entropy-Based Population Diversity Measures in the Traveling Salesman Problem

2020 ◽  
Vol 28 (4) ◽  
pp. 595-619
Author(s):  
Yuichi Nagata
Keyword(s):  
Markov Model ◽  
Traveling Salesman Problem ◽  
Population Based ◽  
Population Diversity ◽  
High Order ◽  
Traveling Salesman ◽  
Variable Order ◽  
Diversity Measures ◽  
The Traveling Salesman Problem ◽  
Permutation Problems

To maintain the population diversity of genetic algorithms (GAs), we are required to employ an appropriate population diversity measure. However, commonly used population diversity measures designed for permutation problems do not consider the dependencies between the variables of the individuals in the population. We propose three types of population diversity measures that address high-order dependencies between the variables to investigate the effectiveness of considering high-order dependencies. The first is formulated as the entropy of the probability distribution of individuals estimated from the population based on an [Formula: see text]-th--order Markov model. The second is an extension of the first. The third is similar to the first, but it is based on a variable order Markov model. The proposed population diversity measures are incorporated into the evaluation function of a GA for the traveling salesman problem to maintain population diversity. Experimental results demonstrate the effectiveness of the three types of high-order entropy-based population diversity measures against the commonly used population diversity measures.

Cross-sectional surveys

2003 ◽  
pp. 111-130 ◽  
Author(s):  
Martin Prince
Keyword(s):  
Research Methodology ◽  
Psychiatric Morbidity ◽  
Historical Context ◽  
Population Based ◽  
Psychiatric Epidemiology ◽  
Sampling Strategies ◽  
Base Population ◽  
Cross Sectional ◽  
Population Sampling ◽  
Study Designs

This chapter considers the strengths and limitations, and the uses and abuses of cross-sectional surveys in psychiatric epidemiology. Certain basic aspects of research methodology; the concept of the base population, sampling strategies, representativeness, the problem of non-response and the practical logistics of population-based research are introduced here, although they are in practice equally relevant to other study designs. The chapter also introduces the problem of bias, arising both from non-response and misclassification. In conclusion, we review major surveys of psychiatric morbidity in a historical context, highlighting methodological developments and discussing the yield of information to be gleaned from them.

scholarly journals Genetics of PlGF plasma levels highlights a role of its receptors and supports the link between angiogenesis and immunity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Ruggiero ◽  
Teresa Nutile ◽  
Stefania Nappo ◽  
Alfonsina Tirozzi ◽  
Celine Bellenguez ◽  
...  
Keyword(s):  
Growth Factor ◽  
Plasma Levels ◽  
Cell Activation ◽  
De Novo ◽  
Inflammatory Diseases ◽  
Meta Analysis ◽  
Population Based ◽  
Isolated Populations ◽  
South Italy ◽  
A Genome

AbstractPlacental growth factor (PlGF) is a member of the vascular endothelial growth factor family and is involved in bone marrow-derived cell activation, endothelial stimulation and pathological angiogenesis. High levels of PlGF have been observed in several pathological conditions especially in cancer, cardiovascular, autoimmune and inflammatory diseases. Little is known about the genetics of circulating PlGF levels. Indeed, although the heritability of circulating PlGF levels is around 40%, no studies have assessed the relation between PlGF plasma levels and genetic variants at a genome-wide level. In the current study, PlGF plasma levels were measured in a population-based sample of 2085 adult individuals from three isolated populations of South Italy. A GWAS was performed in a discovery cohort (N = 1600), followed by a de novo replication (N = 468) from the same populations. The meta-analysis of the discovery and replication samples revealed one signal significantly associated with PlGF circulating levels. This signal was mapped to the PlGF co-receptor coding gene NRP1, indicating its important role in modulating the PlGF plasma levels. Two additional signals, at the PlGF receptor coding gene FLT1 and RAPGEF5 gene, were identified at a suggestive level. Pathway and TWAS analyses highlighted genes known to be involved in angiogenesis and immune response, supporting the link between these processes and PlGF regulation. Overall, these data improve our understanding of the genetic variation underlying circulating PlGF levels. This in turn could lead to new preventive and therapeutic strategies for a wide variety of PlGF-related pathologies.

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