Sökning: "biological cost"

Visar resultat 1 - 5 av 337 avhandlingar innehållade orden biological cost.

  1. 1. Population Differentiation in Solidago virgaurea along Altitudinal Gradients

    Författare :Anna Bergsten; Jon Ågren; Staffan Karlsson; Kari Lehtilä; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; population differentiation; altitudinal gradient; plant nutrient status; resorption efficiency; resorption proficiency; flowering phenology; countergradient variation; reproductive effort; flower production; cost of reproduction; Biology; Biologi; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : Altitudinal gradients offer attractive opportunities for studies of population differentiation in response to environmental heterogeneity. In this thesis, I examined population differentiation along altitudinal gradients by combining common-garden experiments with field studies and experiments in alpine, subalpine and boreal populations of the perennial herb Solidago virgaurea. LÄS MER

  3. 2. Evolutionary Dynamics of Mutation and Gene Transfer in Bacteria

    Författare :Peter A Lind; Dan I Andersson; J. Arjan G. M. de Visser; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; fitness cost; bacterial evolution; gene amplification; mutational biases; GC content; synonymous substitutions; horizontal gene transfer; experimental evolution; Bacteriology; Bakteriologi; Microbiology; Mikrobiologi; Genetics; Genetik; Biology; Biologi; Mikrobiologi; Microbiology;

    Sammanfattning : The study of bacterial evolution is fundamental for addressing current problems of antibiotic resistance and emerging infectious diseases and lays a solid foundation for successful and rational design in biotechnology and synthetic biology. The main aim of this thesis is to test evolutionary hypotheses, largely based on theoretical considerations and sequence analysis, by designing scenarios in a laboratory setting to obtain experimental data. LÄS MER

  4. 3. The biological cost of resistance to antibiotics

    Författare :Johanna Björkman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cell and molecular biology; Cell- och molekylärbiologi; Cell and molecular biology; Cell- och molekylärbiologi; mikrobiologi; Microbiology;

    Sammanfattning : The rate of development and stability of antibiotic resistance are determined by several factors including (i) the mutation rate, (ii) the fitness costs of resistance, and (iii) the ability of bacteria to genetically compensate for such costs.. This study has focused on the experimental measurement of these parameters in antibiotic-resistant S. LÄS MER

  5. 4. Optimal strategies and information in foraging theory

    Författare :Emma Sernland; Högskolan i Skövde; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Bayesian foraging; information use; public information; prior information; negative binomial distribution; group foraging; decision-making; information updating; leaving strategy; Ecology; Ekologi; NATURAL SCIENCES; NATURVETENSKAP; Other biology; Övrig biologi; Naturvetenskap; Natural sciences; information use; Bayesian foraging; public information; prior information; negative binomial distribution; group foraging; decision-making; information updating; leaving strategy; Ecology; Ekologi;

    Sammanfattning : In this thesis, I present both theoretical and empirical work where we have studied how humans and animals use information in situations where they need to continually update their information on the density of a resource. We have found that the amount of information, and the way the information is presented, are important factors for how well decisions are adapted to current circumstances. LÄS MER

  7. 5. Sensitivity, Variation, and Application of Least-Cost Path Models in Landscape Connectivity Analysis and Corridor Planning

    Författare :Rachel Mundeli Murekatete; Takeshi Shirabe; Gyözö Gidofalvi; Jean Pierre Bizimana; Gerhard Navratil; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Landscape connectivity; Conservation corridor; Stepping stones; Effective distance; Geographic Information Systems; Raster data; Land evaluation; Suitability analysis; Cost surface; Suitability surface; Ordinal scale; Least-cost path; Spatial resolution; Landskapsanslutning; Bevarandekorridor; Stegbräda; Effektivt avstånd; Geografiska informationssystem; Rasterdata; Markutvärdering; Lämplighetsanalys; Kostnadsyta; Lämplighetsyta; Ordinal skala; Lägsta kostnadsväg; Rumslig upplösning; Geoinformatik; Geoinformatics;

    Sammanfattning : In recent decades, Rwanda has been affected by the loss and fragmentation of natural habitats for native species of animals and plants. As a consequence, landscape connectivity—i.e. LÄS MER