Search results for "Population"

A Primer on Memetic Algorithms

2012

Memetic Algorithms (MAs) are population-based metaheuristics composed of an evolutionary framework and a set of local search algorithms which are activated within the generation cycle of the external framework, see [376]. The earliest MA implementation has been given in [621] in the context of the Travelling Salesman Problem (TSP) while an early systematic definition has been presented in [615]. The concept of meme is borrowed from philosophy and is intended as the unit of cultural transmission. In other words, complex ideas can be decomposed into memes which propagate andmutate within a population.Culture, in this way, constantly undergoes evolution and tends towards progressive improvemen…

Identification of Replicator Mutator models

2006

The complexity of biology literally calls for quantitative tools in order to support and validate biologists intuition and traditional qualitative descriptions. In this paper, the Replicator-Mutator models for Evolutionary Dynamics are validated/invalidated in a worst-case deterministic setting. These models analyze the DNA and RNA evolution or describe the population dynamics of viruses and bacteria. We identify the Fitness and the Replication Probability parameters of a genetic sequences, subject to a set of stringent constraints to have physical meaning and to guarantee positiveness. The conditional central estimate is determined in order to validate/invalidate the model. The effectivene…

Large Networks of Dynamic Agents: Consensus under Adversarial Disturbances

2012

This paper studies interactions among homogeneous social groups within the framework of large population games. Each group is represented by a network and the behavior described by a two-player repeated game. The contribution is three-fold. Beyond the idea of providing a novel two-level model with repeated games at a lower level and population games at a higher level, we also establish a mean field equilibrium and study state feedback best-response strategies as well as worst-case adversarial disturbances in that context.

Theoretical study of selective H3 receptor antagonists of histamine

1993

Abstract The conformations and charge distributions of three selective H3 receptor antagonists of histamine were determined using the MNDO approach. The results suggest that the conformational flexibilities of betahistine, N α-(2-phenylacetyl)histamine and thioperamide are different; however, the low-energy conformations of these compounds show closely related spatial orderings. The MNDO calculations predict a significant population of the N1H form in the imidazole systems of N α-(2-phenylacetyl)histamine and thioperamide. Our results indicate that the conformational behaviour of H3 antagonists is closely similar to that reported for H2 antagonists of histamine. These results emphasize the …

Thiopurine

2020

Background: Thiopurine methyltransferase (TPMT) plays a significant role in the metabolism of thiopurines, and, for patients with inflammatory bowel disease (IBD), it is useful to perform TPMT genotyping prior to azathioprine (AZA) treatment. In this study, we determined TPMT gene polymorphisms in a cohort of IBD patients in Latvia. Methods: DNA samples were obtained from 244 IBD patients, and qPCR was performed for detection of rs1800462, rs1800460, and rs1142345 single-nucleotide polymorphisms (SNPs). Three common, non-functional TPMT alleles ( TPMT*2, *3B, and *3C) were identified (women, 51%; men, 49%). TPMT*2, *3A, *3B, and *3C allelic variants detected using qPCR were consistent with …

Seasonal population dynamics of Zeuxapta seriolae (Monogenea: Heteraxinidae) parasitising Seriola dumerili (Carangidae) in the Western Mediterranean.

2013

We examined the seasonal and yearly population dynamics of the monogenean pathogen Zeuxapta seriolae on juvenile fish from wild populations of Seriola dumerili. The study is based on bimonthly monitoring between April, 2005 and April, 2007 off Majorca, and newly obtained monogenean population data for juvenile fish from three additional localities in the Western Mediterranean (off Alicante, Corsica and Sardinia). We documented the highest intensities and abundances of Z. seriolae, with mean abundance values similar to or higher than those reported in the single case of wild fish mortalities reported to date. There was a recurrent pattern of seasonal change in infection with Z. seriolae in t…

ON THE EXISTENCE OF LIMIT CYCLES IN OPINION FORMATION PROCESSES UNDER TIME PERIODIC INFLUENCE OF PERSUADERS

2008

This paper concerns a model of opinion formation in a population of interacting individuals under the influence of external leaders or persuaders, which act in a time periodic fashion. The model is formulated within a general framework inspired to a discrete generalized kinetic approach, which has been developed in Ref. 6. It is expressed by a system of non-autonomous nonlinear ordinary differential equations. The dynamics of such a system is investigated and the existence of a globally asymptotically stable periodic solution is analytically proved in three example cases, each one corresponding to a different quantitative choice of the actions of the persuaders. Equivalently, in three part…

2018

Summary Background Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based t…

MARKET ASSESSMENT OF HERBAL SUPPLEMENTS IN ROMANIA FOR A PERIOD OF 10 YEARS USING A HOLISTIC APPROACH

2012

s. PHYTOPHARM 2012 M 102 Obzory po kliniceskoj farmacologii i lekarstvennoj terapii [Reviews of clinical pharmacology and drug therapy] ТОМ 10/2012/2 MARKET ASSESSMENT OF HERBAL SUPPLEMENTS IN ROMANIA FOR A PERIOD OF 10 YEARS USING A HOLISTIC APPROACH © Stoia Mihaela , Oancea Simona , Coman Diana 3 Faculty of Medicine, Lucian Blaga University of Sibiu, Romania Department of Agricultural Sciences, Food Industry and Environmental Protection, Lucian Blaga University of Sibiu, Romania Faculty of Engineering, Lucian Blaga University of Sibiu, Romania Almost nonexistent in the early ‘90s, herbal supplements market gained an important dimension to Romanians, with the growing awareness and the amou…

Differential Translational Efficiency of the mRNAs Isolated from Derepressed and Glucose Repressed Saccharomyces cerevisiae

1987

Summary: Carbon catabolite derepression induced changes in the pool of yeast mRNAs translatable in a protein-synthesizing reticulocyte system. Competition experiments with globin mRNA showed that the mRNA population obtained from derepressed cells possessed a higher translational efficiency than mRNA from repressed cells. The mRNAs that could account for the high translational efficiency of the derepressed mRNA were not detected in cells growing in glucose-rich medium. Analysis of protein synthesis in the presence of 7-methylguanosine 5′-phosphate indicated that the initiation factors recognizing the 5′-terminal structure of capped messengers interacted with lower affinity with the represse…