Sökning: "3-4 year cycles"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden 3-4 year cycles.

  1. 1. Cycles of voles, predators, and alternative prey in boreal Sweden

    Författare :Birger Hörnfeldt; S. Erlinge; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; 3-4 year cycles; Clethrionomys glareolus; Clethrionomys rufocanus; Microtus agrestis; snap-trapping; rate of change; population regulation; delayed density-dependence; time-lag mechanism; seasonality; predation; food; predator avoidance; foraging behaviour; Aegolius funereus; nest boxes; numerical response; nomadism; Vulpes vulpes; Sarcoptes scabiei vulpes; Lepus timidus; Francisella tularensis; Tetraonidae; hunting statistics; zooekologi; Animal Ecology;

    Sammanfattning : Bank voles, grey-sided voles, and field voles had synchronous 3-4 year density cycles with variable amplitudes which averaged about 200-fold in each species. Cycles of vole predators (red fox and Tengmalm's owl), and their (foxes') alternative prey (mountain hare and forest grouse) lagged behind the vole cycles. LÄS MER

  2. 2. Habitat selection and breeding ecology of golden eagles in Sweden

    Författare :Edward Moss; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []

    Sammanfattning : The red-listed Golden Eagle (Aquila chrysaetos) population is estimated between 1200-1400 reproductive individuals in Sweden. This population is unusual as eagles predominantly nest in trees unlike most others that prefer cliffs. LÄS MER

  3. 3. Reading Nature : Developing ecological literacy through teaching

    Författare :Ola Magntorn; Gustav Helldén; Michael Reiss; Linköpings universitet; []

    Sammanfattning : In this study the concept reading nature and its contribution to science education is discussed. Some scientific concepts relevant for reading nature are defined. Reading nature has to do with the ability to recognise organisms and relate them to material cycling and energy flow in the specific habitat which is to be read. LÄS MER

  4. 4. Distribution and activity of pelagic fish - acoustic studies in the Baltic Sea

    Författare :Tomas Didrikas; Sture Hansson; Thomas Mehner; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Pelagic; fish; hydroacoustic; distribution; activity; Baltic; Biology; Biologi;

    Sammanfattning : Fisheries agencies around the Baltic Sea use hydroacoustics to assess stock sizes of herring and sprat. These assessments rely on the assumption that the acoustic properties of Baltic clupeids are the same as North Sea herring. LÄS MER

  5. 5. Health effects in biomedical research laboratory personnel in Sweden : cancer occurrence and reproductive outcomes

    Författare :Helena Wennborg; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; cohort study; laboratory work; organic solvents; brain tumor; breast cancer; melanoma; spontaneous abortion; large-for-gestational age; time-to-pregnancy; fecundability;

    Sammanfattning : The main purposes of this thesis were to study mortality and cancer incidence among individuals working in biological and medical (biomedical) research laboratories as well as to investigate the possible adverse effects on reproduction in female laboratory personnel. This work is based on two cohorts. LÄS MER