Affiner les résultats

Type de document

Institution

Collection spécifique

Langue

Université de Fribourg

6S1/2-6P1/2 transition of Cs atoms in cubic and hexagonal solid ⁴He

Hofer, Adrian ; Moroshkin, Peter ; Ulzega, Simone ; Nettels, Daniel ; Müller-Siebert, Reinhard ; Weis, Antoine

In: Physical Review A, 2007, vol. 76, no. 2, p. 022502

We present a systematic experimental study of the absorption and fluorescence spectra of the 6S1/2-6P1/2 transition in Cs atoms isolated in solid ⁴He matrices. The bubble model developed earlier for alkali-metal atoms in liquid He is revised and applied to the present system. The analysis of the dependencies of absorption and fluorescence wavelengths on He...

Université de Fribourg

Alien species in a warmer world: risks and opportunities

Walther, Gian-Reto ; Roques, Alain ; Hulme, Philip E. ; Sykes, Martin T. ; Pyšek, Petr ; Kühn, Ingolf ; Zobel, Martin ; Bacher, Sven ; Botta-Dukát, Zoltán ; Bugmann, Harald ; Czúcz, Bálint ; Dauber, Jens ; Hickler, Thomas ; Jarošík, Vojtěch ; Kenis, Marc ; Klotz, Stefan ; Minchin, Dan ; Moora, Mari ; Nentwig, Wolfgang ; Ott, Jürgen ; Panov, Vadim E. ; Reineking, Björn ; Robinet, Christelle ; Semenchenko, Vitaliy ; Solarz, Wojciech ; Thuiller, Wilfried ; Vilà, Montserrat ; Vohland, Katrin ; Settele, Josef

In: Trends in Ecology & Evolution, 2009, vol. 24, no. 12, p. 686-693

Climate change and biological invasions are key processes affecting global biodiversity, yet their effects have usually been considered separately. Here, we emphasise that global warming has enabled alien species to expand into regions in which they previously could not survive and reproduce. Based on a review of climate-mediated biological invasions of plants, invertebrates, fishes and birds, we...

Université de Fribourg

Bax function in the absence of mitochondria in the primitive protozoan Giardia lamblia

Hehl, Adrian B. ; Regos, Attila ; Schraner, Elisabeth ; Schneider, André

In: PLoS ONE, 2007, vol. 2, no. 5, p. e488

Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia...

Université de Fribourg

Body size–climate relationships of European spiders

Entling, Wiebke ; Schmidt-Entling, Martin H. ; Bacher, Sven ; Brandl, Roland ; Nentwig, Wolfgang

In: Journal of Biogeography, 2009///doi: 10.1111/j.1365-2699.2009.02216.x

Aim: Geographic body size patterns of mammals and birds can be partly understood under the framework of Bergmann's rule. Climatic influences on body size of invertebrates, however, appear highly variable and lack a comparable, generally applicable theoretical framework. We derived predictions for body size–climate relationships for spiders from the literature and tested them using three...

Université de Fribourg

The brain-specific Neural Zinc Finger transcription factor 2b (NZF-2b/7ZFMyt1) causes suppression of cocaine-induced locomotor activity

Chandrasekar, Vijay ; Dreyer, Jean-Luc

In: Neurobiology of Disease, 2009, vol. 37, no. 1, p. 86-98

Chronic cocaine induces high expression of the brain-specific Neural-Zinc-Finger transcription factor-2b (NZF-2b/7ZFMyt1), particularly in the mesolimbic dopaminergic pathway, resulting in a 11-fold increase in NZF-2b/7ZFMyt1 expression in the Nucleus Accumbens (NAc). Overexpression of this gene in the NAc with a NZF-2b/7ZFMyt1-expressing lentivirus resulted in >55% decrease in locomotor activity...

Université de Fribourg

The brain under self-control: modulation of inhibitory and monitoring cortical networks during hypnotic paralysis

Cojan, Yann ; Waber, Lakshmi ; Schwartz, Sophie ; Rossier, Laurent ; Forster, Alain ; Vuilleumier, Patrik

In: Neuron, 2009, vol. 62, no. 6, p. 862-875

Brain mechanisms of hypnosis are poorly known. Cognitive accounts proposed that executive attentional systems may cause selective inhibition or disconnection of some mental operations. To assess motor and inhibitory brain circuits during hypnotic paralysis, we designed a go-nogo task while volunteers underwent functional magnetic resonance imaging (fMRI) in three conditions: normal state,...

Université de Fribourg

The Cdc42 effectors ste20, Cla4, and Skm1 down-regulate the expression of genes involved in sterol uptake by a mitogen-activated protein kinase-independent pathway

Lin, Meng ; Unden, Heike ; Jacquier, Nicolas ; Schneiter, Roger ; Just, Ursula ; Höfken, Thomas

In: Molecular Biology of the Cell, 2009, vol. 20, no. 22, p. 4826-4837

In Saccharomyces cerevisiae, the Rho-type GTPase Cdc42 regulates polarized growth through its effectors, including the p21-activated kinases (PAKs) Ste20, Cla4, and Skm1. Previously, we demonstrated that Ste20 interacts with several proteins involved in sterol synthesis that are crucial for cell polarization. Under anaerobic conditions, sterols cannot be synthesized and need to be imported into...