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Université de Fribourg

The effect of learning on experimental evolution of resource preference in Drosophila melanogaster

Kawecki, Tadeusz J. ; Mery, Frederic

In: Evolution, 2004, vol. 58, no. 4, p. 757-767

Learning is thought to be adaptive in variable environments, whereas constant, predictable environments are supposed to favor unconditional, genetically fixed responses. A dichotomous view of behavior as either learned or innate ignores a potential evolutionary interaction between the learned and innate components of a behavioral response. We addressed this interaction in the context of...

Université de Fribourg

Conceptual issues in local adaptation

Kawecki, Tadeusz J. ; Ebert, Dieter

In: Ecology Letters, 2004, vol. 7, p. 1225-1241

Studies of local adaptation provide important insights into the power of natural selection relative to gene flow and other evolutionary forces. They are a paradigm for testing evolutionary hypotheses about traits favoured by particular environmental factors. This paper is an attempt to summarize the conceptual framework for local adaptation studies. We first review theoretical work relevant for...

Université de Fribourg

The dynamic localization and novel functions of the Ipl1/Aurora protein kinase

Buvelot, Stéphanie ; Conzelmann, Andreas (Dir.)

Thèse de doctorat : Université de Fribourg : 2003 ; no 1400.

Proper chromosome segregation is a crucial event for accurate cell division. Defects in chromosome segregation lead to genetic instability and aneuploidy and are correlated with cancer. The laboratory studies chromosome segregation in the budding yeast Saccharomyces cerevisiae. Since this process is highly conserved among eukaryotes, studies in yeast will provide fundamental understanding of this...

Université de Fribourg

Proteine and cell adsorption : topographical dependency and adlayer viscoelastic properties determined with oscillation amplitude of quartz resonator

Galli Marxer, Carine ; Schlapbach, Louis (Dir.) ; Collaud Coen, Martine (Codir.)

Thèse de doctorat : Université de Fribourg : 2002 ; no 1388.

The biocompatibility of materials in implant or biosensor fields strongly depends on first interactions occurring between a given surface and a biological environment. It is well-known that a living body brought into contact with a surface will induce protein adsorption, which creates the interface, on which proteins or cells will adsorb. The interactions can be influenced by modifying the...

Université de Fribourg

Developments and applications of four wave mixing spectroscopies in the picosecond and femtosecond time regimes

Gumy, Jean-Claude ; Vauthey, Eric (Dir.) ; Haselbach, Edwin (Codir.)

Thèse de doctorat : Université de Fribourg : 2000 ; no 1302.

This thesis describes the development and the applications of four wave mixing techniques (Transient Grating (TG), Coherent Anti-Stokes Raman Scattering (CARS) and Transient Dichroism (TD)), to investigate processes taking place in the pico- and femtosecond time scales. In the first part of the work, the TG technique is described using both the holography and the nonlinear optics formalisms. The...

Université de Fribourg

Nuclear receptors as vehicles for gene transfer

Ceppi, Maurizio ; Rusconi, Sandro (Dir.)

Thèse de doctorat : Université de Fribourg : 2000 ; Nr. 1328.

Human gene therapy can be defined as the directed transfer of exogenous genes or other nucleotide sequences into somatic cells, for the purpose of preventing, correcting or healing various diseases. This novel approach to the therapy of human disorders is based on the realization that many previous medical treatments have usually been directed at the consequences of causative defects or at...

Université de Fribourg

Modelling markets dynamics : minority games and beyond

Challet, Damien ; Zhang, Yi-Cheng (Dir.) ; Dacorogna, Michel (Codir.)

Thèse de doctorat : Université de Fribourg : 2000 ; no 1303.

Starting from the El Farol's bar problem, we introduce the minority game, an extremely simple model of competition between adaptive agents. We study its properties, and find that it displays a phase transition with symmetry breaking. An adequate mathematical formalism is introduced and reveals the spin glass nature of the model. We prove that available information is a Lyapunov function for this...

Université de Fribourg

Study of 110Cd using the (n, n'γ) reaction and 114Te using the (α, 2n) reaction

Corminboeuf, Frédéric ; Jolie, Jan (Dir.)

Thèse de doctorat : Université de Fribourg : 2000 ; Nr. 1326.

The study of nuclear structure is one of the research domains in nuclear physics which have known an important development. It has asked a great effort for the experimenters as well as the theoreticians to study in detail the nuclear many-body problem. In the framework of this thesis, we have tested several nuclear models for two nuclei: 110Cd and 114Te. This choice has not been made at random....

Université de Fribourg

Experimental Evolutionary Biology of Learning in “drosophila melanogaster”

Mery, Frederic ; Kawecki, Tadeusz (Dir.)

Thèse de doctorat : Université de Fribourg : 2003 ; 1403.

Many animals, including small invertebrates, have the capacity to modify their behaviour based on experience - they can learn. The ability to learn is itself a product of evolution, and the degree to which a given behaviour is modified by learning varies among species and among different types of behaviour. For an evolutionary biologist this raises the question of the conditions under which...

Université de Fribourg

Weak-coupling instabilities of two-dimensional lattice electrons

Binz, Benedikt ; Baeriswyl, Dionys (Dir.) ; Douçot, Benoit (Codir.)

Thèse de doctorat : Université de Fribourg : 2002 ; 1374.

Interacting e1ectrons in two dimensions are of particular interest in relation to high-temperature superconductivity. In this thesis, I study a two-dimensional extended Hubbard model in the weak coupling limit. Quite generally, the electron gas is unstable towards a superconducting state even in the absence of phonons. However in the special case of a half-filled band, the Fermi surface is nested...