ALBERT

Description: A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved gravitational-wave sources of astrophysical and cosmological origin. It should carry unique signatures from the earliest epochs in the evolution of the Universe, inaccessible to standard astrophysical observations. Direct measurements of the amplitude of this background are therefore of fundamental importance for understanding the evolution of the Universe when it was younger than one minute. Here we report limits on the amplitude of the stochastic gravitational-wave background using the data from a two-year science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). Our result constrains the energy density of the stochastic gravitational-wave background normalized by the critical energy density of the Universe, in the frequency band around 100 Hz, to be 〈6.9 x 10(-6) at 95% confidence. The data rule out models of early Universe evolution with relatively large equation-of-state parameter, as well as cosmic (super)string models with relatively small string tension that are favoured in some string theory models. This search for the stochastic background improves on the indirect limits from Big Bang nucleosynthesis and cosmic microwave background at 100 Hz.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉LIGO Scientific Collaboration & Virgo Collaboration -- Abbott, B P -- Abbott, R -- Acernese, F -- Adhikari, R -- Ajith, P -- Allen, B -- Allen, G -- Alshourbagy, M -- Amin, R S -- Anderson, S B -- Anderson, W G -- Antonucci, F -- Aoudia, S -- Arain, M A -- Araya, M -- Armandula, H -- Armor, P -- Arun, K G -- Aso, Y -- Aston, S -- Astone, P -- Aufmuth, P -- Aulbert, C -- Babak, S -- Baker, P -- Ballardin, G -- Ballmer, S -- Barker, C -- Barker, D -- Barone, F -- Barr, B -- Barriga, P -- Barsotti, L -- Barsuglia, M -- Barton, M A -- Bartos, I -- Bassiri, R -- Bastarrika, M -- Bauer, Th S -- Behnke, B -- Beker, M -- Benacquista, M -- Betzwieser, J -- Beyersdorf, P T -- Bigotta, S -- Bilenko, I A -- Billingsley, G -- Birindelli, S -- Biswas, R -- Bizouard, M A -- Black, E -- Blackburn, J K -- Blackburn, L -- Blair, D -- Bland, B -- Boccara, C -- Bodiya, T P -- Bogue, L -- Bondu, F -- Bonelli, L -- Bork, R -- Boschi, V -- Bose, S -- Bosi, L -- Braccini, S -- Bradaschia, C -- Brady, P R -- Braginsky, V B -- Brand, J F J van den -- Brau, J E -- Bridges, D O -- Brillet, A -- Brinkmann, M -- Brisson, V -- Van Den Broeck, C -- Brooks, A F -- Brown, D A -- Brummit, A -- Brunet, G -- Bullington, A -- Bulten, H J -- Buonanno, A -- Burmeister, O -- Buskulic, D -- Byer, R L -- Cadonati, L -- Cagnoli, G -- Calloni, E -- Camp, J B -- Campagna, E -- Cannizzo, J -- Cannon, K C -- Canuel, B -- Cao, J -- Carbognani, F -- Cardenas, L -- Caride, S -- Castaldi, G -- Caudill, S -- Cavaglia, M -- Cavalier, F -- Cavalieri, R -- Cella, G -- Cepeda, C -- Cesarini, E -- Chalermsongsak, T -- Chalkley, E -- Charlton, P -- Chassande-Mottin, E -- Chatterji, S -- Chelkowski, S -- Chen, Y -- Christensen, N -- Chung, C T Y -- Clark, D -- Clark, J -- Clayton, J H -- Cleva, F -- Coccia, E -- Cokelaer, T -- 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Vocca, H -- Vorvick, C -- Vyachanin, S P -- Waldman, S J -- Wallace, L -- Ward, H -- Ward, R L -- Was, M -- Weidner, A -- Weinert, M -- Weinstein, A J -- Weiss, R -- Wen, L -- Wen, S -- Wette, K -- Whelan, J T -- Whitcomb, S E -- Whiting, B F -- Wilkinson, C -- Willems, P A -- Williams, H R -- Williams, L -- Willke, B -- Wilmut, I -- Winkelmann, L -- Winkler, W -- Wipf, C C -- Wiseman, A G -- Woan, G -- Wooley, R -- Worden, J -- Wu, W -- Yakushin, I -- Yamamoto, H -- Yan, Z -- Yoshida, S -- Yvert, M -- Zanolin, M -- Zhang, J -- Zhang, L -- Zhao, C -- Zotov, N -- Zucker, M E -- Zweizig, J -- England -- Nature. 2009 Aug 20;460(7258):990-4. doi: 10.1038/nature08278.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Lists of participants and their affiliations appear at the end of the paper.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19693079" target="_blank"〉PubMed〈/a〉

Description: The symbiosis between fungus-growing ants and the fungi they cultivate for food has been shaped by 50 million years of coevolution. Phylogenetic analyses indicate that this long coevolutionary history includes a third symbiont lineage: specialized microfungal parasites of the ants' fungus gardens. At ancient levels, the phylogenies of the three symbionts are perfectly congruent, revealing that the ant-microbe symbiosis is the product of tripartite coevolution between the farming ants, their cultivars, and the garden parasites. At recent phylogenetic levels, coevolution has been punctuated by occasional host-switching by the parasite, thus intensifying continuous coadaptation between symbionts in a tripartite arms race.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Currie, Cameron R -- Wong, Bess -- Stuart, Alison E -- Schultz, Ted R -- Rehner, Stephen A -- Mueller, Ulrich G -- Sung, Gi-Ho -- Spatafora, Joseph W -- Straus, Neil A -- New York, N.Y. -- Science. 2003 Jan 17;299(5605):386-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA. ccurrie@ku.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12532015" target="_blank"〉PubMed〈/a〉