Search results for "PET"

Lielvaru (ASV un Ķīnas) sāncensība 21. gadsimtā

2022

Maģistra darba “Lielvaru (ASV un Ķīnas) sāncensība 21. gadsimtā” mērķis ir vairāku lielvaru augšupejas un lejupslīdes teoriju aplūkošana un analīze, saistot tās ar empīriskajiem novērojumiem par šādu sāncensību. Maģistra darbā apskatītās teorijas tiks pretnostatītas ASV un Ķīnas kā lielvaru sāncensībai mūsdienās, tādējādi veicinot izpratni par iespējamo šādas sāncensības izcelsmi un norisi, izrietot no vēsturiskiem gadījumiem, kas saistīti ar lielvaru sāncensību. Darba teorētiskā bāze ietver izklāstu par lielvaru raksturojumu un vairāku citu jēdzienu apskatīšanu, kā arī apskata četras lielvaru sāncensības teorijas. Maģistra darba empīrisko daļu veido lielvaru sāncensības vēsturiskā ietvara …

Binding mode analysis of ABCA7 for the prediction of novel Alzheimer's disease therapeutics

2021

Graphical abstract

Efficacité interne de l'enseignement primaire aux pays de la Communauté Economique des Pays des Grands Lacs (CEPGL) : question approfondie sur le Rwa…

2011

This PhD study has been achieved with objective to carry out the level of internal efficiency of the primary education in the CEPGL countries and the progress reaches toward the education for all after the period of ethnic and armed conflicts. In addition, specifically for Rwanda, to underline the individual, families and school factors explanatory of the repetition and drop-out in the primary schools. The data of our analysis come from different reports of ministries, international organizations and publications of researchers. The analysis of the primary education inside CEPGL countries, by the indicators that document education supply and demand, show that, after the period of conflicts,…

Quasi-linear time computation of the abelian periods of a word

2012

Computing abelian periods in words

2011

International audience

Carbon and nitrogen stable isotope ratios of soils and grasses as indicators of soil characteristics and biological taxa

2019

Abstract The use of stable isotope techniques can assist in understanding interactions of plants with various abiotic and biotic processes. In the research, we focused on carbon (C) and nitrogen (N) isotopes because they are the most important resources influencing plant function and the biogeochemical cycles. The 13C/12C and 15N/14N ratios in plants and in soils and the relationships between these ratios and biological and environmental factors of widely distributed native C3 plants (couch grass, plantain and yarrow) collected from two sites in St. Petersburg, Russia were studied. The soil characteristics of the sites were rather different. This had a significant effect on the isotope rati…

Review paper: Seasonal variation as a determinant of population structure in rotifers reproducing by cyclical parthenogenesis

1998

Monogonont rotifers live in habitats that display extensively variation in both biotic and abiotic components. Much of this variation is seasonal and therefore predictable for a given pond or lake. In 1972, King proposed one physiological and two genetic models presenting alternative modes of adaptation to this temporal variation. Our purpose in the present paper is to review and evaluate how our knowledge of the seasonal structure of rotifer populations has changed in the past 25 years. Seasonal changes in clone frequencies have been reported from three studies of natural populations using electrophoretic analysis of isozymes. In one of these studies there was evidence for substantial temp…

2011

Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in these forest ecosyst…

Environmental drivers of breeding sites in blackfly species of medical and veterinary importance in eastern Spain

2021

Geographical distribution and abundance of the pupae of six blackfly species of medical and veterinary concern were studied in eastern Spain according to three different sets of explanatory variables including in-stream variables, both (i) abiotic (i.e., physicochemical) and (ii) biotic (i.e., richness and abundance of either taxonomically or ecologically close related taxa), as well as (iii) meteorological and landscape variables. The results showed specific habitat requirements for pupation in Simulium (Boophthora) erythrocephalum (De Geer, 1776) and Simulium (Wilhelmia) equinum (Linnaeus, 1758), two of the six species studied regarding elevation and temperature. While the rest of the spe…

Modelling temperature-dependent dynamics of single and mixed infections in a plant virus

2022

Multiple viral infection is an important issue in health and agriculture with strong impacts on society and the economy. Several investigations have dealt with the population dynamics of viruses with different dynamic properties, focusing on strain competition during multiple infections and the effects on viruses’ hosts. Recent interest has been on how multiple infections respond to abiotic factors such as temperature (T). This is especially important in the case of plant pathogens, whose dynamics could be affected significantly by global warming. However, few mathematical models incorporate the effect of T on parasite fitness, especially in mixed infections. Here, we investigate simple mat…