Suto I.,Nagoya University |
Kawamura K.,Nissei Gakuen |
Hagimoto S.,ADMATECHS Co. |
Teraishi A.,NTT Comware |
Tanaka Y.,Japan National Institute of Advanced Industrial Science and Technology
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012
Long-term evolution is thought to take opportunities that arise as a consequence of mass extinction (as argued, for example, by Gould, 2002) and the following biotic recovery, but there is absolutely no evidence for this being the case. However, our study shows that eutrophication by oceanic mixing also played a part in the enhancement of several evolutionary events amongst marine organisms, and these results could indicate that the rates of oceanic biodiversification may be slowed if upwelling becomes weakened by future global warming. This paper defines three distinct evolutionary events of resting spores of the marine diatom genus Chaetoceros, to reconstruct past upwelling through the analysis of several DSDP, ODP and land-based successions from the North, South and equatorial Pacific as well as the Atlantic Ocean during the past 40. million years. The Atlantic Chaetoceros Explosion (A. CE) event occurred across the E/O boundary in the North Atlantic, and is characterized by resting spore diversification that occurred as a consequence of the onset of upwelling following changes in thermohaline circulation through global cooling in the early Oligocene. Pacific Chaetoceros Explosion events-1 and -2 (PA. CE-1 and PA. CE-2) are characterized by relatively higher occurrences of iron input following the Himalayan uplift and aridification at 8.5. Ma and ca. 2.5. Ma in the North Pacific region. These events not only enhanced the diversification and increased abundance of primary producers, including that of Chaetoceros, other diatoms and seaweeds, but also stimulated the evolution of zooplankton and larger predators, such as copepods and marine mammals, which ate these phytoplankton and plants. Current thinking suggests new evolutionary niches open up after a mass extinction, but our study finds that eutrophication can also stimulate evolutionary diversification. Moreover, in the opposite fashion, our results show that as thermohaline circulation abates, global warming progresses and the ocean surface becomes warmer, many marine organisms will be affected by the environmental degradation. © 2012 Elsevier B.V.
Kawamae N.,NTT Comware
WWW'12 - Proceedings of the 21st Annual Conference on World Wide Web Companion | Year: 2012
Our proposal, identifying sentiments in N-grams (ISN), focuses on both word order and phrases, and the interdependency between specific ratings and corresponding sentiments in texts to detect subjective information. Copyright is held by the International World Wide Web Conference Committee (IW3C2).
Kawamae N.,Nippon Telegraph and Telephone |
Kawamae N.,NTT Comware |
Higashinaka R.,Nippon Telegraph and Telephone
Proceedings of the 19th International Conference on World Wide Web, WWW '10 | Year: 2010
This paper presents a topic model that detects topic distributions over time. Our proposed model, Trend Detection Model (TDM) introduces a latent trend class variable into each document. The trend class has a probability distribution over topics and a continuous distribution over time. Experiments using our data set show that TDM is useful as a generative model in the analysis of the evolution of trends. © 2010 Copyright is held by the author/owner(s).
Kawamae N.,NTT Comware
SIGIR 2010 Proceedings - 33rd Annual International ACM SIGIR Conference on Research and Development in Information Retrieval | Year: 2010
This paper presents a hierarchical topic model that simultaneously captures topics and author's interests. Our proposed model, the Author Interest Topic model (AIT), introduces a latent variable with a probability distribution over topics into each document. Experiments on a research paper corpus show that AIT is very useful as a generative model. © 2010 ACM.
Asano T.,NTT Comware
NTT Technical Review | Year: 2012
NTT COMWARE Corporation America Branch is focusing on providing new business value by monitoring emerging trends of venture-capital companies and the telecommunications industry in Silicon Valley and disseminating this information to its customers as well as to the NTT Group. This article introduces our business and activities.