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Université de Fribourg

Unveiling the Semimetallic Nature of 1$T$-TiSe$_2$ by Doping its Charge Density Wave

Jaouen, Thomas ; Rumo, Maxime ; Hildebrand, Baptiste ; Mottas, Marie-Laure ; Nicholson, Christopher W. ; Kremer, Geoffroy ; Salzmann, Björn ; Vanini, Fabiano ; Barreteau, C. ; Giannini, E. ; Beck, Hans-Peter ; Aebi, Philipp ; Monney, Claude

The semimetallic or semiconducting nature of the transition metal dichalcogenide 1$T$-TiSe$_2$ remains under debate after many decades mainly due to the fluctuating nature of its 2 x 2 x 2 charge-density-wave (CDW) phase at room- temperature. In this letter, using angle-resolved photoemission spectroscopy, we unambiguously demonstrate that the 1$T$-TiSe$_2$ normal state is semimetallic with ...

Université de Fribourg

Dental anomaly in a middle Miocene fossil of the genus Spermophilinus (Rodentia, Sciuridae) from southern Germany

Prieto, Jérôme ; Rummel, Michael ; Peláez-Campomanes, Pablo ; Vasilyan, Davit

In: Fossil Imprint, 2020, vol. 76, no. 1, p. 174-180

The maxillary presented in this work has been excavated in the middle Miocene karst filling Petersbuch 136 (Germany, Bavaria) and shows the oldest evidence of dental anomaly in a sciurid. The aberrant morphology, probably hyperdontia or no replacement of roots of deciduous teeth, affects the area of the P3, a tooth that is generally not well documented in the Spermophilinus record.

Université de Fribourg

First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia

Mörs, Thomas ; Reguero, Marcelo ; Vasilyan, Davit

In: Scientific Reports, 2020, vol. 10, p. 5051

Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documented previously from Antarctica, in contrast to all other continents. Here we report a fossil ilium and an ornamented skull bone that can be attributed to the Recent, South American, anuran family Calyptocephalellidae or helmeted frogs, representing the first modern amphibian found in Antarctica. The two bone...

Université de Fribourg

Role of a higher-dimensional interaction in stabilizing charge density waves in quasi-one-dimensional ${\mathrm{NbSe}}_{3}$ revealed by angle-resolved photoemission spectroscopy

Nicholson, Christopher W. ; Schwier, Eike Fabian ; Shimada, K. ; Berger, Helmuth ; Hoesch, M. ; Berthod, C. ; Monney, Claude

In: Physical Review B, 2020, vol. 101, no. 4, p. 045412

We revisit charge density wave (CDW) behavior in the archetypal quasi-one- dimensional (quasi-1D) material NbSe3 by high-resolution angle-resolved photoemission spectroscopy measurements utilizing a microfocused laser with a photon energy of 6.3 eV. We present a detailed view of the electronic structure of this complex multiband system and unambiguously resolve CDW gaps at the Fermi level ...

Université de Fribourg

The fossil record of the genus Varanus from the Southern Caucasus (Armenia, Georgia)

Vasilyan, Davit ; Bukhsianidze, Maia

In: PeerJ, 2020, p. e8322

The Southern Caucasus, with its special geographic position and complex topography, is a well-known biodiversity hotspot. However, the formation of this hotspot remains largely unstudied. To reveal this, a thorough study of the fossil record of the region is necessary. In the present paper, we describe for the first time fossil monitor lizards (Varanus sp.) from two late Miocene localities from...

Université de Fribourg

The relationship of obesity predicting decline in executive functioning is attenuated with greater leisure activities in old age

Ihle, Andreas ; Gouveia, Élvio R. ; Gouveia, Bruna R. ; Zuber, Sascha ; Mella, Nathalie ; Desrichard, Olivier ; Cullati, Stéphane ; Oris, Michel ; Maurer, Jürgen ; Kliegel, Matthias

In: Aging & Mental Health, 2019, p. 1–8

Objectives: We investigated the longitudinal relationship between obesity and subsequent decline in executive functioning over six years as measured through performance changes in the Trail Making Test (TMT). We also examined whether this longitudinal relationship differed by key markers of cognitive reserve (education, occupation, and leisure activities), taking into account age, sex, and...

Université de Fribourg

Magnetic-field effects on one-dimensional Anderson localization of light

Schertel, Lukas ; Irtenkauf, Oliver ; Aegerter, Christof M. ; Maret, Georg ; Aubry, Geoffroy J.

In: Physical Review A, 2019, vol. 100, no. 4, p. 043818

Transport of coherent waves in multiple-scattering media may exhibit fundamental, nonintuitive phenomena such as halt of diffusion by disorder called Anderson localization. For electromagnetic waves, this phenomenon was observed only in one and two dimensions so far. However, none of these experiments studied the contribution of reciprocal paths nor their manipulation by external fields. In...

Université de Fribourg

A review of the fossil record of nonbaenid turtles of the clade Paracryptodira

Joyce, Walter G. ; Anquetin, Jérémy

In: Bulletin of the Peabody Museum of Natural History, 2019, vol. 60, no. 2, p. 129–155

The fossil record of nonbaenid paracryptodires ranges from the Late Jurassic (Kimmeridgian) to the Paleocene of North America and Europe only. Earlier remains may be present as early as the Middle Jurassic (Bathonian). Only a single dispersal event is documented between the two continents after their breakup during the Cretaceous in the form of the appearance of the Compsemys lineage in the ...

Università della Svizzera italiana

Antigen-specific Th17 cells are primed by distinct and complementary dendritic cell subsets in oropharyngeal candidiasis

Trautwein-Weidner, Kerstin ; Gladiator, André ; Kirchner, Florian R. ; Becattini, Simone ; Rülicke, Thomas ; Sallusto, Federica ; LeibundGut-Landmann, Salomé

In: PLoS pathogens, 2015, vol. 11, no. 10, p. e1005164

Candida spp. can cause severe and chronic mucocutaneous and systemic infections in immunocompromised individuals. Protection from mucocutaneous candidiasis depends on T helper cells, in particular those secreting IL-17. The events regulating T cell activation and differentiation toward effector fates in response to fungal invasion in different tissues are poorly understood. Here we generated...

Université de Fribourg

Diffusing wave microrheology of highly scattering concentrated monodisperse emulsions

Kim, Ha Seong ; Şenbil, Nesrin ; Zhang, Chi ; Scheffold, Frank ; Mason, Thomas G.

In: Proceedings of the National Academy of Sciences, 2019, vol. 116, no. 16, p. 7766–7771

Motivated by improvements in diffusing wave spectroscopy (DWS) for nonergodic, highly optically scattering soft matter and by cursory treatment of collective scattering effects in prior DWS microrheology experiments, we investigate the low-frequency plateau elastic shear moduli G′p of concentrated, monodisperse, disordered oil-in- water emulsions as droplets jam. In such experiments, the...