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Institution

University of Fribourg

EducationFribourg, Freiburg, Switzerland
About: University of Fribourg is a education organization based out in Fribourg, Freiburg, Switzerland. It is known for research contribution in the topics: Population & Glacier. The organization has 6040 authors who have published 14975 publications receiving 542500 citations. The organization is also known as: UNIFR & Universität Freiburg.


Papers
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Journal ArticleDOI
TL;DR: The origin and significance of the self-interaction force between both dipoles is discussed in connection with that of the angular distribution of scattered light and of the extinction cross section.
Abstract: We present a study of the optical force on a small particle with both electric and magnetic response, immersed in an arbitrary non-absorbing medium, due to a generic incident electromagnetic field. Expressions for the gradient force, radiation pressure and curl components are obtained for the force due to both the electric and magnetic dipoles excited in the particle. In particular, for the magnetic force we tentatively introduce the concept of curl of the spin angular momentum density of the magnetic field, also expressed in terms of 3D generalizations of the Stokes parameters. From the formal analogy between the conservation of momentum and the optical theorem, we discuss the origin and significance of the self-interaction force between both dipoles; this is done in connection with that of the angular distribution of scattered light and of the extinction cross section.

299 citations

Journal ArticleDOI
20 May 2011-Science
TL;DR: In this paper, the authors used optical ellipsometry and low-energy muon spin rotation to show that superlattices with LaNiO 3 as thin as two unit cells undergo a sequence of collective metal-insulator and antiferromagnetic transitions as a function of decreasing temperature.
Abstract: The competition between collective quantum phases in materials with strongly correlated electrons depends sensitively on the dimensionality of the electron system, which is difficult to control by standard solid-state chemistry. We have fabricated superlattices of the paramagnetic metal lanthanum nickelate (LaNiO 3 ) and the wide-gap insulator lanthanum aluminate (LaAlO 3 ) with atomically precise layer sequences. We used optical ellipsometry and low-energy muon spin rotation to show that superlattices with LaNiO 3 as thin as two unit cells undergo a sequence of collective metal-insulator and antiferromagnetic transitions as a function of decreasing temperature, whereas samples with thicker LaNiO 3 layers remain metallic and paramagnetic at all temperatures. Metal-oxide superlattices thus allow control of the dimensionality and collective phase behavior of correlated-electron systems.

299 citations

Journal ArticleDOI
TL;DR: New developments in the industry for AM-related products for agriculture, horticulture, and landscaping are discussed, and future potential and limits toward the use of AM fungi for plant production are highlighted.
Abstract: Arbuscular mycorrhiza (AM) is the most common symbiotic association of plants with microbes AM fungi occur in the majority of natural habitats and they provide a range of important ecological services, in particular by improving plant nutrition, stress resistance and tolerance, soil structure and fertility AM fungi also interact with most crop plants including cereals, vegetables, and fruit trees, therefore, they receive increasing attention for their potential use in sustainable agriculture Basic research of the past decade has revealed the existence of a dedicated recognition and signaling pathway that is required for AM Furthermore, recent evidence provided new insight into the exchange of nutritional benefits between the symbiotic partners The great potential for application of AM has given rise to a thriving industry for AM-related products for agriculture, horticulture, and landscaping Here, we discuss new developments in these fields, and we highlight future potential and limits toward the use of AM fungi for plant production

299 citations

Journal ArticleDOI
TL;DR: It is argued that there is little theoretical justification and no empirical evidence for the plan that social interventions that lower pathogen transmission will indirectly select lower virulence because of a trade-off between transmission and virulence, and direct selection against virulence itself might be a more rewarding approach.

299 citations

Journal ArticleDOI
TL;DR: In this paper, a short introductory paper illustrates some key issues concerning extremes by focusing on daily temperature extremes defined using quantiles and threshold exceedances, and highlights several features, some of them taken from the 2003 heat wave that affected Europe, in particular significant changes in the trends of quantiles in the course of the 20th century, differences in the altitudinal behavior of maximum or minimum temperatures, and close links between means and the extreme quantiles of daily temperatures.

299 citations


Authors

Showing all 6204 results

NameH-indexPapersCitations
Jens Nielsen1491752104005
Sw. Banerjee1461906124364
Hans Peter Beck143113491858
Patrice Nordmann12779067031
Abraham Z. Snyder12532991997
Csaba Szabó12395861791
Robert Edwards12177574552
Laurent Poirel11762153680
Thomas Münzel116105557716
David G. Amaral11230249094
F. Blanc107151458418
Markus Stoffel10262050796
Vincenzo Balzani10147645722
Enrico Bertini9986538167
Sandeep Kumar94156338652
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202367
2022348
20211,110
20201,112
2019966
2018924