Institution
University of Fribourg
Education•Fribourg, 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 & Context (language use). The organization has 6040 authors who have published 14975 publications receiving 542500 citations. The organization is also known as: UNIFR & Universität Freiburg.
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TL;DR: The hand representations of the SMA and M1 strongly differ with respect to the strength and distribution of callosal connectivity with the former having more powerful and widespread callosal connections with a number of motor fields of the opposite cortex than the latter.
Abstract: The goal of the present neuroanatomical study in macaque monkeys was twofold: (1) to clarify whether the hand representation of the primary motor cortex (M1) has a transcallosal projection to M1 of the opposite hemisphere; (2) to compare the topography and density of transcallosal connections for the hand representations of M1 and the supplementary motor area (SMA). The hand areas of M1 and the SMA were identified by intracortical microstimulation and then injected either with retrograde tracer substances in order to label the neurons of origin in the contralateral motor cortical areas (four monkeys) or, with an anterograde tracer, to establish the regional distribution and density of terminal fields in the opposite motor cortical areas (two monkeys). The main results were: (1) The hand representation of M1 exhibited a modest homotopic callosal projection, as judged by the small number of labeled neurons within the region corresponding to the contralateral injection. A modest heterotopic callosal projection originated from the opposite supplementary, premotor, and cingulate motor areas. (2) In contrast, the SMA hand representation showed a dense callosal projection to the opposite SMA. The SMA was found to receive also dense heterotopic callosal projections from the contralateral rostral and caudal cingulate motor areas, moderate projections from the lateral premotor cortex, and sparse projections from M1. (3) After injection of an anterograde tracer (biotinylated dextran amine) in the hand representation of M1, only a few small patches of axonal label were found in the corresponding region of M1, as well as in the lateral premotor cortex; virtually no label was found in the SMA or in cingulate motor areas. Injections of the same anterograde tracer in the hand representation of the SMA, however, resulted in dense and widely distributed axonal terminal fields in the opposite SMA, premotor cortex, and cingulate motor areas, while labeled terminals were clearly less dense in M1. It is concluded that the hand representations of the SMA and M1 strongly differ with respect to the strength and distribution of callosal connectivity with the former having more powerful and widespread callosal connections with a number of motor fields of the opposite cortex than the latter. These anatomical results support the proposition of the SMA being a bilaterally organized system, possibly contributing to bimanual coordination.
387 citations
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TL;DR: In this article, the authors investigated several properties of the minority game and gave an analytical expression of σ 2/N in the N ⪡ 2 M region. But they did not consider the influence of identical players on their gain and on the systems performance.
Abstract: We investigate further several properties of the minority game we have recently introduced. We explain the origin of the phase transition and give an analytical expression of σ2/N in the N ⪡ 2 M region. The ability of the players to learn a given payoff is also analyzed, and we show that the Darwinian evolution process tends to a self-organized state, in particular, the lifetime distribution is a power-law with exponent −2. Furthermore, we study the influence of identical players on their gain and on the systems performance. Finally, we show that large brains always take advantage of small brains.
383 citations
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University of Vienna1, Stellenbosch University2, Zoological Society of London3, University College London4, International Union for Conservation of Nature and Natural Resources5, Lincoln University (Pennsylvania)6, Leibniz Association7, Free University of Berlin8, University of Auckland9, Academy of Sciences of the Czech Republic10, Charles University in Prague11, Taizhou University12, University of Konstanz13, Kwame Nkrumah University of Science and Technology14, National and Kapodistrian University of Athens15, University of Fribourg16, University of Oldenburg17, Scion18, University of Sassari19, Universidade Nova de Lisboa20, University of Porto21, Charles Darwin Foundation22, Durham University23, Okinawa Institute of Science and Technology24, University of Concepción25, University of Hong Kong26, CABI27, Martin Luther University of Halle-Wittenberg28, Helmholtz Centre for Environmental Research - UFZ29, United States Forest Service30, Bielefeld University31, University of Bern32, Botanical Society of Britain and Ireland33, Environment Agency34, Smithsonian Institution35, Institut national de la recherche agronomique36, University of Silesia in Katowice37, Landcare Research38, National Agriculture and Food Research Organization39
TL;DR: Using a global database of the first regional records of alien species covering the years 1500–2005, a surprisingly high proportion of species in recent records that have never been recorded as alien before are detected.
Abstract: Our ability to predict the identity of future invasive alien species is largely based upon knowledge of prior invasion history Emerging alien species—those never encountered as aliens before—therefore pose a significant challenge to biosecurity interventions worldwide Understanding their temporal trends, origins, and the drivers of their spread is pivotal to improving prevention and risk assessment tools Here, we use a database of 45,984 first records of 16,019 established alien species to investigate the temporal dynamics of occurrences of emerging alien species worldwide Even after many centuries of invasions the rate of emergence of new alien species is still high: One-quarter of first records during 2000–2005 were of species that had not been previously recorded anywhere as alien, though with large variation across taxa Model results show that the high proportion of emerging alien species cannot be solely explained by increases in well-known drivers such as the amount of imported commodities from historically important source regions Instead, these dynamics reflect the incorporation of new regions into the pool of potential alien species, likely as a consequence of expanding trade networks and environmental change This process compensates for the depletion of the historically important source species pool through successive invasions We estimate that 1–16% of all species on Earth, depending on the taxonomic group, qualify as potential alien species These results suggest that there remains a high proportion of emerging alien species we have yet to encounter, with future impacts that are difficult to predict
382 citations
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TL;DR: The spontaneous onset of a one-dimensional, incommensurate modulation of the spin system in the high-transition-temperature superconductor YBa2Cu3O6 suggests that soft spin fluctuations are a microscopic route toward electronic liquid crystals and that nematic order can coexist with high-tem temperature superconductivity in underdoped cuprates.
Abstract: Electronic phases with symmetry properties matching those of conventional liquid crystals have recently been discovered in transport experiments on semiconductor heterostructures and metal oxides at millikelvin temperatures. We report the spontaneous onset of a one-dimensional, incommensurate modulation of the spin system in the high-transition-temperature superconductor YBa2Cu3O6.45 upon cooling below ∼150 kelvin, whereas static magnetic order is absent above 2 kelvin. The evolution of this modulation with temperature and doping parallels that of the in-plane anisotropy of the resistivity, indicating an electronic nematic phase that is stable over a wide temperature range. The results suggest that soft spin fluctuations are a microscopic route toward electronic liquid crystals and that nematic order can coexist with high-temperature superconductivity in underdoped cuprates.
382 citations
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TL;DR: The findings suggest that HIF-1 is specifically involved in the regulation of muscle adaptations after hypoxia training, and fine-tuning of the training response is recognized at the molecular level, and with less sensitivity also at the structural level, but not at global functional responses like maximal O(2) uptake or maximal power output.
Abstract: This study was performed to explore changes in gene expression as a consequence of exercise training at two levels of intensity under normoxic and normobaric hypoxic conditions (corresponding to an altitude of 3,850 m). Four groups of human subjects trained five times a week for a total of 6 wk on a bicycle ergometer. Muscle biopsies were taken, and performance tests were carried out before and after the training period. Similar increases in maximal O2 uptake (8.3–13.1%) and maximal power output (11.4–20.8%) were found in all groups. RT-PCR revealed elevated mRNA concentrations of the α-subunit of hypoxia-inducible factor 1 (HIF-1) after both high- (+82.4%) and low (+78.4%)-intensity training under hypoxic conditions. The mRNA of HIF-1α736, a splice variant of HIF-1α newly detected in human skeletal muscle, was shown to be changed in a similar pattern as HIF-1α. Increased mRNA contents of myoglobin (+72.2%) and vascular endothelial growth factor (+52.4%) were evoked only after high-intensity training in h...
382 citations
Authors
Showing all 6204 results
Name | H-index | Papers | Citations |
---|---|---|---|
Jens Nielsen | 149 | 1752 | 104005 |
Sw. Banerjee | 146 | 1906 | 124364 |
Hans Peter Beck | 143 | 1134 | 91858 |
Patrice Nordmann | 127 | 790 | 67031 |
Abraham Z. Snyder | 125 | 329 | 91997 |
Csaba Szabó | 123 | 958 | 61791 |
Robert Edwards | 121 | 775 | 74552 |
Laurent Poirel | 117 | 621 | 53680 |
Thomas Münzel | 116 | 1055 | 57716 |
David G. Amaral | 112 | 302 | 49094 |
F. Blanc | 107 | 1514 | 58418 |
Markus Stoffel | 102 | 620 | 50796 |
Vincenzo Balzani | 101 | 476 | 45722 |
Enrico Bertini | 99 | 865 | 38167 |
Sandeep Kumar | 94 | 1563 | 38652 |