Institution
University of Groningen
Education•Groningen, Groningen, Netherlands•
About: University of Groningen is a education organization based out in Groningen, Groningen, Netherlands. It is known for research contribution in the topics: Population & Context (language use). The organization has 36346 authors who have published 69116 publications receiving 2940370 citations. The organization is also known as: Rijksuniversiteit Groningen & RUG.
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01 Jun 2010TL;DR: To describe the system's ability for reaching consensus, a new concept about the generalized algebraic connectivity is defined for strongly connected networks and then extended to the strongly connected components of the directed network containing a spanning tree.
Abstract: This paper considers a second-order consensus problem for multiagent systems with nonlinear dynamics and directed topologies where each agent is governed by both position and velocity consensus terms with a time-varying asymptotic velocity. To describe the system's ability for reaching consensus, a new concept about the generalized algebraic connectivity is defined for strongly connected networks and then extended to the strongly connected components of the directed network containing a spanning tree. Some sufficient conditions are derived for reaching second-order consensus in multiagent systems with nonlinear dynamics based on algebraic graph theory, matrix theory, and Lyapunov control approach. Finally, simulation examples are given to verify the theoretical analysis.
982 citations
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TL;DR: A phenomenological theory of inhomogeneous ferroelectric magnets is presented, which describes their thermodynamics and magnetic field behavior, and shows that electric polarization can also be induced at domain walls and that magnetic vortices carry electric charge.
Abstract: It was recently observed that the ferroelectrics showing the strongest sensitivity to an applied magnetic field are spiral magnets. We present a phenomenological theory of inhomogeneous ferroelectric magnets, which describes their thermodynamics and magnetic field behavior, e.g., dielectric susceptibility anomalies at magnetic transitions and sudden flops of electric polarization in an applied magnetic field. We show that electric polarization can also be induced at domain walls and that magnetic vortices carry electric charge.
982 citations
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École Normale Supérieure1, University of Exeter2, Norwich Research Park3, Alfred Wegener Institute for Polar and Marine Research4, University of Groningen5, Wageningen University and Research Centre6, Max Planck Society7, Ludwig Maximilian University of Munich8, Commonwealth Scientific and Industrial Research Organisation9, Centre national de la recherche scientifique10, Stanford University11, Karlsruhe Institute of Technology12, Atlantic Oceanographic and Meteorological Laboratory13, Cooperative Institute for Marine and Atmospheric Studies14, Geophysical Institute, University of Bergen15, Bjerknes Centre for Climate Research16, Japan Agency for Marine-Earth Science and Technology17, University of Maryland, College Park18, National Institute of Water and Atmospheric Research19, National Oceanic and Atmospheric Administration20, Appalachian State University21, Flanders Marine Institute22, Augsburg College23, ETH Zurich24, Leibniz Institute of Marine Sciences25, University of East Anglia26, Woods Hole Research Center27, University of Illinois at Urbana–Champaign28, University of Hong Kong29, Utrecht University30, Netherlands Environmental Assessment Agency31, University of Paris32, Hobart Corporation33, University of Tasmania34, University of Bern35, National Center for Atmospheric Research36, University of Reading37, Cooperative Institute for Research in Environmental Sciences38, National Institute for Environmental Studies39, Russian Academy of Sciences40, Goddard Space Flight Center41, Leibniz Institute for Baltic Sea Research42, Princeton University43, Met Office44, Lund University45, Auburn University46, Food and Agriculture Organization47, VU University Amsterdam48
TL;DR: In this article, the authors describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties, including emissions from land use and land use change, and show that the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere is a measure of imperfect data and understanding of the contemporary carbon cycle.
Abstract: . Accurate assessment of anthropogenic carbon dioxide ( CO2 ) emissions and
their redistribution among the atmosphere, ocean, and terrestrial biosphere
– the “global carbon budget” – is important to better understand the
global carbon cycle, support the development of climate policies, and
project future climate change. Here we describe data sets and methodology to
quantify the five major components of the global carbon budget and their
uncertainties. Fossil CO2 emissions ( EFF ) are based on energy
statistics and cement production data, while emissions from land use change
( ELUC ), mainly deforestation, are based on land use and land use change
data and bookkeeping models. Atmospheric CO2 concentration is measured
directly and its growth rate ( GATM ) is computed from the annual changes
in concentration. The ocean CO2 sink ( SOCEAN ) and terrestrial
CO2 sink ( SLAND ) are estimated with global process models
constrained by observations. The resulting carbon budget imbalance
( BIM ), the difference between the estimated total emissions and the
estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a
measure of imperfect data and understanding of the contemporary carbon
cycle. All uncertainties are reported as ±1σ . For the last
decade available (2009–2018), EFF was 9.5±0.5 GtC yr −1 ,
ELUC 1.5±0.7 GtC yr −1 , GATM 4.9±0.02 GtC yr −1 ( 2.3±0.01 ppm yr −1 ), SOCEAN 2.5±0.6 GtC yr −1 , and SLAND 3.2±0.6 GtC yr −1 , with a budget
imbalance BIM of 0.4 GtC yr −1 indicating overestimated emissions
and/or underestimated sinks. For the year 2018 alone, the growth in EFF was
about 2.1 % and fossil emissions increased to 10.0±0.5 GtC yr −1 , reaching 10 GtC yr −1 for the first time in history,
ELUC was 1.5±0.7 GtC yr −1 , for total anthropogenic
CO2 emissions of 11.5±0.9 GtC yr −1 ( 42.5±3.3 GtCO2 ). Also for 2018, GATM was 5.1±0.2 GtC yr −1 ( 2.4±0.1 ppm yr −1 ), SOCEAN was 2.6±0.6 GtC yr −1 , and SLAND was 3.5±0.7 GtC yr −1 , with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407.38±0.1 ppm averaged over 2018. For 2019, preliminary data for the first 6–10 months indicate a reduced growth in EFF of +0.6 % (range of
−0.2 % to 1.5 %) based on national emissions projections for China, the
USA, the EU, and India and projections of gross domestic product corrected
for recent changes in the carbon intensity of the economy for the rest of
the world. Overall, the mean and trend in the five components of the global
carbon budget are consistently estimated over the period 1959–2018, but
discrepancies of up to 1 GtC yr −1 persist for the representation of
semi-decadal variability in CO2 fluxes. A detailed comparison among
individual estimates and the introduction of a broad range of observations
shows (1) no consensus in the mean and trend in land use change emissions
over the last decade, (2) a persistent low agreement between the different
methods on the magnitude of the land CO2 flux in the northern
extra-tropics, and (3) an apparent underestimation of the CO2
variability by ocean models outside the tropics. This living data update
documents changes in the methods and data sets used in this new global
carbon budget and the progress in understanding of the global carbon cycle
compared with previous publications of this data set (Le Quere et
al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by
this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein
et al., 2019).
981 citations
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TL;DR: Since the total culturable counts were only a fraction of the total microscopic counts, the contribution of bifidobacteria to the total intestinal microflora was overestimated by almost 10-fold when cultural methods were used as the sole method for enumeration.
Abstract: Three 16S rRNA hybridization probes were developed and tested for genus-specific detection of Bifidobacterium species in the human fecal flora. Variable regions V2, V4, and V8 of the 16S rRNA contained sequences unique to this genus and proved applicable as target sites for oligodeoxynucleotide probes. Determination of the genus specificity of the oligonucleotides was performed by whole-cell hybridization with fluorescein isothiocyanate-labelled probes. To this end, cells were fixed on glass slides, hybridized with the probes, and monitored by videomicroscopy. In combination with image analysis, this allowed quantification of the fluorescence per cell and objective evaluation of hybridization experiments. One of the probes developed was used to determine the population of Bifidobacterium spp. in human fecal samples. A comparison was made with results obtained by cultural methods for enumeration. Since both methods gave similar population estimates, it was concluded that all bifidobacteria in feces were culturable. However, since the total culturable counts were only a fraction of the total microscopic counts, the contribution of bifidobacteria to the total intestinal microflora was overestimated by almost 10-fold when cultural methods were used as the sole method for enumeration.
979 citations
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TL;DR: Room-temperature electrical injection and detection of spin currents and observe spin accumulation in an all-metal lateral mesoscopic spin valve, where ferromagnetic electrodes are used to drive a spin-polarized current into crossed copper strips is reported.
Abstract: Finding a means to generate, control and use spin-polarized currents represents an important challenge for spin-based electronics1,2,3, or ‘spintronics’. Spin currents and the associated phenomenon of spin accumulation can be realized by driving a current from a ferromagnetic electrode into a non-magnetic metal or semiconductor. This was first demonstrated over 15 years ago in a spin injection experiment4 on a single crystal aluminium bar at temperatures below 77 K. Recent experiments5,6,7,8 have demonstrated successful optical detection of spin injection in semiconductors, using either optical injection by circularly polarized light or electrical injection from a magnetic semiconductor. However, it has not been possible to achieve fully electrical spin injection and detection at room temperature. Here we report room-temperature electrical injection and detection of spin currents and observe spin accumulation in an all-metal lateral mesoscopic spin valve, where ferromagnetic electrodes are used to drive a spin-polarized current into crossed copper strips. We anticipate that larger signals should be obtainable by optimizing the choice of materials and device geometry.
978 citations
Authors
Showing all 36692 results
Name | H-index | Papers | Citations |
---|---|---|---|
Ronald C. Kessler | 274 | 1332 | 328983 |
Nicholas J. Wareham | 212 | 1657 | 204896 |
André G. Uitterlinden | 199 | 1229 | 156747 |
Lei Jiang | 170 | 2244 | 135205 |
Brenda W.J.H. Penninx | 170 | 1139 | 119082 |
Richard H. Friend | 169 | 1182 | 140032 |
Panos Deloukas | 162 | 410 | 154018 |
Jerome I. Rotter | 156 | 1071 | 116296 |
Christopher M. Dobson | 150 | 1008 | 105475 |
Dirk Inzé | 149 | 647 | 74468 |
Scott T. Weiss | 147 | 1025 | 74742 |
Dieter Lutz | 139 | 671 | 67414 |
Wilmar B. Schaufeli | 137 | 513 | 95718 |
Cisca Wijmenga | 136 | 668 | 86572 |
Arnold B. Bakker | 135 | 506 | 103778 |