TY  - JOUR
A1  - Aldoretta, E. J.
A1  - St-Louis, N.
A1  - Richardson, N. D.
A1  - Moffat, Anthony F. J.
A1  - Eversberg, T.
A1  - Hill, G. M.
A1  - Shenar, Tomer
A1  - Artigau, E.
A1  - Gauza, B.
A1  - Knapen, J. H.
A1  - Kubat, Jiří
A1  - Kubatova, Brankica
A1  - Maltais-Tariant, R.
A1  - Munoz, M.
A1  - Pablo, H.
A1  - Ramiaramanantsoa, T.
A1  - Richard-Laferriere, A.
A1  - Sablowski, D. P.
A1  - Simon-Diaz, S.
A1  - St-Jean, L.
A1  - Bolduan, F.
A1  - Dias, F. M.
A1  - Dubreuil, P.
A1  - Fuchs, D.
A1  - Garrel, T.
A1  - Grutzeck, G.
A1  - Hunger, T.
A1  - Kuesters, D.
A1  - Langenbrink, M.
A1  - Leadbeater, R.
A1  - Li, D.
A1  - Lopez, A.
A1  - Mauclaire, B.
A1  - Moldenhawer, T.
A1  - Potter, M.
A1  - dos Santos, E. M.
A1  - Schanne, L.
A1  - Schmidt, J.
A1  - Sieske, H.
A1  - Strachan, J.
A1  - Stinner, E.
A1  - Stinner, P.
A1  - Stober, B.
A1  - Strandbaek, K.
A1  - Syder, T.
A1  - Verilhac, D.
A1  - Waldschlaeger, U.
A1  - Weiss, D.
A1  - Wendt, A.
T1  - An extensive spectroscopic time series of three Wolf-Rayet stars - I. The lifetime of large-scale structures in the wind of WR 134
JF  - Monthly notices of the Royal Astronomical Society
N2  - During the summer of 2013, a 4-month spectroscopic campaign took place to observe the variabilities in three Wolf-Rayet stars. The spectroscopic data have been analysed for WR 134 (WN6b), to better understand its behaviour and long-term periodicity, which we interpret as arising from corotating interaction regions (CIRs) in the wind. By analysing the variability of the He ii lambda 5411 emission line, the previously identified period was refined to P = 2.255 +/- 0.008 (s.d.) d. The coherency time of the variability, which we associate with the lifetime of the CIRs in the wind, was deduced to be 40 +/- 6 d, or similar to 18 cycles, by cross-correlating the variability patterns as a function of time. When comparing the phased observational grey-scale difference images with theoretical grey-scales previously calculated from models including CIRs in an optically thin stellar wind, we find that two CIRs were likely present. A separation in longitude of Delta I center dot a parts per thousand integral 90A degrees was determined between the two CIRs and we suggest that the different maximum velocities that they reach indicate that they emerge from different latitudes. We have also been able to detect observational signatures of the CIRs in other spectral lines (C iv lambda lambda 5802,5812 and He i lambda 5876). Furthermore, a DAC was found to be present simultaneously with the CIR signatures detected in the He i lambda 5876 emission line which is consistent with the proposed geometry of the large-scale structures in the wind. Small-scale structures also show a presence in the wind, simultaneously with the larger scale structures, showing that they do in fact co-exist.
KW  - instabilities
KW  - methods: data analysis
KW  - techniques: spectroscopic
KW  - stars: individual: WR 134
KW  - stars: massive
KW  - stars: Wolf-Rayet
Y1  - 2016
U6  - https://doi.org/10.1093/mnras/stw1188
SN  - 0035-8711
SN  - 1365-2966
VL  - 460
SP  - 3407
EP  - 3417
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Ramiaramanantsoa, Tahina
A1  - Moffat, Anthony F. J.
A1  - Harmon, Robert
A1  - Ignace, R.
A1  - St-Louis, Nicole
A1  - Vanbeveren, Dany
A1  - Shenar, Tomer
A1  - Pablo, Herbert
A1  - Richardson, Noel D.
A1  - Howarth, Ian D.
A1  - Stevens, Ian R.
A1  - Piaulet, Caroline
A1  - St-Jean, Lucas
A1  - Eversberg, Thomas
A1  - Pigulski, Andrzej
A1  - Popowicz, Adam
A1  - Kuschnig, Rainer
A1  - Zoclonska, Elzbieta
A1  - Buysschaert, Bram
A1  - Handler, Gerald
A1  - Weiss, Werner W.
A1  - Wade, Gregg A.
A1  - Rucinski, Slavek M.
A1  - Zwintz, Konstanze
A1  - Luckas, Paul
A1  - Heathcote, Bernard
A1  - Cacella, Paulo
A1  - Powles, Jonathan
A1  - Locke, Malcolm
A1  - Bohlsen, Terry
A1  - Chené, André-Nicolas
A1  - Miszalski, Brent
A1  - Waldron, Wayne L.
A1  - Kotze, Marissa M.
A1  - Kotze, Enrico J.
A1  - Böhm, Torsten
T1  - BRITE-Constellation high-precision time-dependent photometry of the early O-type supergiant zeta Puppis unveils the photospheric drivers of its small- and large-scale wind structures
JF  - Monthly notices of the Royal Astronomical Society
N2  - From 5.5 months of dual-band optical photometric monitoring at the 1 mmag level, BRITE-Constellation has revealed two simultaneous types of variability in the O4I(n)fp star ζ Puppis: one single periodic non-sinusoidal component superimposed on a stochastic component. The monoperiodic component is the 1.78-d signal previously detected by Coriolis/Solar Mass Ejection Imager, but this time along with a prominent first harmonic. The shape of this signal changes over time, a behaviour that is incompatible with stellar oscillations but consistent with rotational modulation arising from evolving bright surface inhomogeneities. By means of a constrained non-linear light-curve inversion algorithm, we mapped the locations of the bright surface spots and traced their evolution. Our simultaneous ground-based multisite spectroscopic monitoring of the star unveiled cyclical modulation of its He ii λ4686 wind emission line with the 1.78-d rotation period, showing signatures of corotating interaction regions that turn out to be driven by the bright photospheric spots observed by BRITE. Traces of wind clumps are also observed in the He ii λ4686 line and are correlated with the amplitudes of the stochastic component of the light variations probed by BRITE at the photosphere, suggesting that the BRITE observations additionally unveiled the photospheric drivers of wind clumps in ζ Pup and that the clumping phenomenon starts at the very base of the wind. The origins of both the bright surface inhomogeneities and the stochastic light variations remain unknown, but a subsurface convective zone might play an important role in the generation of these two types of photospheric variability.
KW  - techniques: photometric
KW  - techniques: spectroscopic
KW  - stars: massive
KW  - stars: rotation
KW  - starspots
KW  - supergiants
KW  - stars: winds, outflows
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx2671
SN  - 0035-8711
SN  - 1365-2966
VL  - 473
IS  - 4
SP  - 5532
EP  - 5569
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Pfestorf, H.
A1  - Weiss, L.
A1  - Müller, J.
A1  - Boch, Steffen
A1  - Socher, S. A.
A1  - Prati, Daniel
A1  - Schöning, Ingo
A1  - Weisser, W.
A1  - Fischer, M.
A1  - Jeltsch, Florian
T1  - Community mean traits as additional indicators to monitor effects of land-use intensity On grassland plant diversity
JF  - Perspectives in plant ecology, evolution and systematics
N2  - Semi-natural grasslands, biodiversity hotspots in Central-Europe, suffer from the cessation of traditional land-use. Amount and intensity of these changes challenge current monitoring frameworks typically based on classic indicators such as selected target species or diversity indices. Indicators based on plant functional traits provide an interesting extension since they reflect ecological strategies at individual and ecological processes at community levels. They typically show convergent responses to gradients of land-use intensity over scales and regions, are more directly related to environmental drivers than diversity components themselves and enable detecting directional changes in whole community dynamics. However, probably due to their labor- and cost intensive assessment in the field, they have been rarely applied as indicators so far.
 Here we suggest overcoming these limitations by calculating indicators with plant traits derived from online accessible databases. Aiming to provide a minimal trait set to monitor effects of land-use intensification on plant diversity we investigated relationships between 12 community mean traits, 2 diversity indices and 6 predictors of land-use intensity within grassland communities of 3 different regions in Germany (part of the German 'Biodiversity Exploratory' research network). By standardization of traits and diversity measures, use of null models and linear mixed models we confirmed (i) strong links between functional community composition and plant diversity, (ii) that traits are closely related to land-use intensity, and (iii) that functional indicators are equally, or even more sensitive to land-use intensity than traditional diversity indices. The deduced trait set consisted of 5 traits, i.e., specific leaf area (SLA), leaf dry matter content (LDMC), seed release height, leaf distribution, and onset of flowering. These database derived traits enable the early detection of changes in community structure indicative for future diversity loss. As an addition to current monitoring measures they allow to better link environmental drivers to processes controlling community dynamics.
KW  - Biodiversity Exploratories
KW  - Biological conservation
KW  - (Semi-natural) Grasslands
KW  - Plant functional traits
KW  - Indicators
KW  - Land-use intensity
Y1  - 2013
U6  - https://doi.org/10.1016/j.ppees.2012.10.003
SN  - 1433-8319
VL  - 15
IS  - 1
SP  - 1
EP  - 11
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Pablo, Herbert
A1  - Richardson, Noel D.
A1  - Moffat, Anthony F. J.
A1  - Corcoran, Michael
A1  - Shenar, Tomer
A1  - Benvenuto, Omar
A1  - Fuller, Jim
A1  - Naze, Yael
A1  - Hoffman, Jennifer L.
A1  - Miroshnichenko, Anatoly
A1  - Apellaniz, Jesus Maiz
A1  - Evans, Nancy
A1  - Eversberg, Thomas
A1  - Gayley, Ken
A1  - Gull, Ted
A1  - Hamaguchi, Kenji
A1  - Hamann, Wolf-Rainer
A1  - Henrichs, Huib
A1  - Hole, Tabetha
A1  - Ignace, Richard
A1  - Iping, Rosina
A1  - Lauer, Jennifer
A1  - Leutenegger, Maurice
A1  - Lomax, Jamie
A1  - Nichols, Joy
A1  - Oskinova, Lida
A1  - Owocki, Stan
A1  - Pollock, Andy
A1  - Russell, Christopher M. P.
A1  - Waldron, Wayne
A1  - Buil, Christian
A1  - Garrel, Thierry
A1  - Graham, Keith
A1  - Heathcote, Bernard
A1  - Lemoult, Thierry
A1  - Li, Dong
A1  - Mauclaire, Benjamin
A1  - Potter, Mike
A1  - Ribeiro, Jose
A1  - Matthews, Jaymie
A1  - Cameron, Chris
A1  - Guenther, David
A1  - Kuschnig, Rainer
A1  - Rowe, Jason
A1  - Rucinski, Slavek
A1  - Sasselov, Dimitar
A1  - Weiss, Werner
T1  - A coordinated X-Ray and optical campaign of the nearest massive eclipsing binary, delta ORIONIS Aa. III. Analysis of optical photometric (most) and spectroscopic (ground based) variations
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report on both high-precision photometry from the Microvariability and Oscillations of Stars (MOST) space telescope and ground-based spectroscopy of the triple system delta Ori A, consisting of a binary O9.5II+early-B (Aa1 and Aa2) with P = 5.7 days, and a more distant tertiary (O9 IV P > 400 years). This data was collected in concert with X-ray spectroscopy from the Chandra X-ray Observatory. Thanks to continuous coverage for three weeks, the MOST light curve reveals clear eclipses between Aa1 and Aa2 for the first time in non-phased data. From the spectroscopy, we have a well-constrained radial velocity (RV) curve of Aa1. While we are unable to recover RV variations of the secondary star, we are able to constrain several fundamental parameters of this system and determine an approximate mass of the primary using apsidal motion. We also detected second order modulations at 12 separate frequencies with spacings indicative of tidally influenced oscillations. These spacings have never been seen in a massive binary, making this system one of only a handful of such binaries that show evidence for tidally induced pulsations.
KW  - binaries: close
KW  - binaries: eclipsing
KW  - stars: early-type
KW  - stars: individual (delta Ori A)
KW  - stars: mass-loss
KW  - stars: variables: general
Y1  - 2015
U6  - https://doi.org/10.1088/0004-637X/809/2/134
SN  - 0004-637X
SN  - 1538-4357
VL  - 809
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - GEN
A1  - Foster, William J.
A1  - Garvie, Christopher L.
A1  - Weiss, Anna M.
A1  - Muscente, A. Drew
A1  - Aberhan, Martin
A1  - Counts, John W.
A1  - Martindale, Rowan C.
T1  - Resilience of marine invertebrate communities during the early Cenozoic hyperthermals
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The hyperthermal events of the Cenozoic, including the Paleocene-Eocene Thermal Maximum, provide an opportunity to investigate the potential effects of climate warming on marine ecosystems. Here, we examine the shallow benthic marine communities preserved in the late Cretaceous to Eocene strata on the Gulf Coastal Plain (United States). In stark contrast to the ecological shifts following the end-Cretaceous mass extinction, our data show that the early Cenozoic hyperthermals did not have a long-term impact on the generic diversity nor composition of the Gulf Coastal Plain molluscan communities. We propose that these communities were resilient to climate change because molluscs are better adapted to high temperatures than other taxa, as demonstrated by their physiology and evolutionary history. In terms of resilience, these communities differ from other shallow-water carbonate ecosystems, such as reef communities, which record significant changes during the early Cenozoic hyperthermals. These data highlight the strikingly different responses of community types, i.e., the almost imperceptible response of molluscs versus the marked turnover of foraminifera and reef faunas. The impact on molluscan communities may have been low because detrimental conditions did not devastate the entire Gulf Coastal Plain, allowing molluscs to rapidly recolonise vacated areas once harsh environmental conditions ameliorated.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1410 
KW  - eocene thermal maximum
KW  - gulf coastal plain
KW  - climate-change
KW  - ocean acidification
KW  - extinction event
KW  - carbon-cycle
KW  - heat-stress
KW  - origination
KW  - ecosystems
KW  - diversity
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516011
SN  - 1866-8372
IS  - 1
ER  - 
TY  - JOUR
A1  - Foster, William J.
A1  - Garvie, Christopher L.
A1  - Weiss, Anna M.
A1  - Muscente, A. Drew
A1  - Aberhan, Martin
A1  - Counts, John W.
A1  - Martindale, Rowan C.
T1  - Resilience of marine invertebrate communities during the early Cenozoic hyperthermals
JF  - Scientific Reports
N2  - The hyperthermal events of the Cenozoic, including the Paleocene-Eocene Thermal Maximum, provide an opportunity to investigate the potential effects of climate warming on marine ecosystems. Here, we examine the shallow benthic marine communities preserved in the late Cretaceous to Eocene strata on the Gulf Coastal Plain (United States). In stark contrast to the ecological shifts following the end-Cretaceous mass extinction, our data show that the early Cenozoic hyperthermals did not have a long-term impact on the generic diversity nor composition of the Gulf Coastal Plain molluscan communities. We propose that these communities were resilient to climate change because molluscs are better adapted to high temperatures than other taxa, as demonstrated by their physiology and evolutionary history. In terms of resilience, these communities differ from other shallow-water carbonate ecosystems, such as reef communities, which record significant changes during the early Cenozoic hyperthermals. These data highlight the strikingly different responses of community types, i.e., the almost imperceptible response of molluscs versus the marked turnover of foraminifera and reef faunas. The impact on molluscan communities may have been low because detrimental conditions did not devastate the entire Gulf Coastal Plain, allowing molluscs to rapidly recolonise vacated areas once harsh environmental conditions ameliorated.
KW  - eocene thermal maximum
KW  - gulf coastal plain
KW  - climate-change
KW  - ocean acidification
KW  - extinction event
KW  - carbon-cycle
KW  - heat-stress
KW  - origination
KW  - ecosystems
KW  - diversity
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-58986-5
SN  - 2045-2322
VL  - 10
IS  - 1
SP  - 1
EP  - 11
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Weiss, Jonathan R.
A1  - Qiu, Qiang
A1  - Barbot, Sylvain
A1  - Wright, Tim J.
A1  - Foster, James H.
A1  - Saunders, Alexander
A1  - Brooks, Benjamin A.
A1  - Bevis, Michael
A1  - Kendrick, Eric
A1  - Ericksen, Todd L.
A1  - Avery, Jonathan
A1  - Smalley, Robert
A1  - Cimbaro, Sergio R.
A1  - Lenzano, Luis Eduardo
A1  - Baron, Jorge
A1  - Carlos Baez, Juan
A1  - Echalar, Arturo
T1  - Illuminating subduction zone rheological properties in the wake of a giant earthquake
JF  - Science Advances
N2  - Deformation associated with plate convergence at subduction zones is accommodated by a complex system involving fault slip and viscoelastic flow. These processes have proven difficult to disentangle. The 2010 M-w 8.8 Maule earthquake occurred close to the Chilean coast within a dense network of continuously recording Global Positioning System stations, which provide a comprehensive history of surface strain. We use these data to assemble a detailed picture of a structurally controlled megathrust fault frictional patchwork and the three-dimensional rheological and time-dependent viscosity structure of the lower crust and upper mantle, all of which control the relative importance of afterslip and viscoelastic relaxation during postseismic deformation. These results enhance our understanding of subduction dynamics including the interplay of localized and distributed deformation during the subduction zone earthquake cycle.
Y1  - 2019
U6  - https://doi.org/10.1126/sciadv.aax6720
SN  - 2375-2548
VL  - 5
IS  - 12
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  -