Sökning: "Per Arnqvist"

Hittade 4 avhandlingar innehållade orden Per Arnqvist.

  1. 1. Functional clustering methods and marital fertility modelling

    Författare :Per Arnqvist; Sara Sjöstedt de Luna; Leif Nilsson; Helle Sørensen; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; censoring; Coale-Trussell model; EM-algorithm; functional data analysis; functional clustering; marital fertility; normal approximation; Poisson process; varved lake sediments; warping; Mathematical Statistics; matematisk statistik;

    Sammanfattning : This thesis consists of two parts.The first part considers further development of a model used for marital fertility, the Coale-Trussell's fertility model, which is based on age-specific fertility rates. A new model is suggested using individual fertility data and a waiting time after pregnancies. LÄS MER

  3. 2. Expression and function of IGF-I and insulin receptors in human micro- and macrovascular cells

    Författare :Simona I. Chisalita; Hans J. Arnqvist; Torbjorn Lindström; Per-Anders Jansson; Linköpings universitet; []
    Nyckelord :MEDICINE; MEDICIN;

    Sammanfattning : Insulin-like growth factor and insulin are phylogenetically closely related polypeptides and have large structural and biological similarities. Low circulating insulin-like growth factor-I (IGF-I), diabetes as well as insulin resistance have been implicated in the pathogenesis of cardiovascular disease, but the mechanisms involved are still not clear. LÄS MER

  4. 3. The role of Assortative Mating in the Initial Stages of Sympatric and Parapatric Speciation

    Författare :Emma Rova; Mats Björklund; Göran Arnqvist; James Mallet; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Callosobruchus maculatus; host fidelity; assortative mating; inbreeding; experimental evidence; sympatric speciation; parapatric speciation; Biology; Biologi; Biologi med inriktning mot zooekologi; Biology with specialization in Animal Ecology;

    Sammanfattning : Divergence in the face of gene flow is perhaps the most wildly disputed subject among researchers through time. The debate is an old one and we find its origin as far back as the era of Darwin. LÄS MER

  5. 4. Postmating Sexual Selection and its Role in Population Divergence in Beetles

    Författare :Claudia Fricke; Göran Arnqvist; David Hosken; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Callosobruchus maculatus; postmating sexual selection; speciation; laboratory selection experiment; divergence; Biologi; Biology; Biologi;

    Sammanfattning : Speciation is the process describing the formation of new species and is at the heart of evolutionary biology. According to the biological species concept only reproductively isolated forms are regarded good species. This thesis aims at identifying evolutionary processes that cause population divergence and, ultimately, speciation. LÄS MER