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Morioka, Japan

Iwate University is a national university in Morioka, Iwate, Japan. This university has been called "Gandai" in Japan. The predecessor of the school was founded in 1876, and was chartered as a university in 1949. Wikipedia.

Shimono H.,Iwate University
Agriculture, Ecosystems and Environment | Year: 2011

Screening for cultivars that respond strongly to elevated atmospheric CO2 concentration ([CO2]) is essential for increasing the productivity of C3 crops in the future high-[CO2] world. However, the cost of research facilities capable of increasing [CO2], such as free air-CO2 enrichment (FACE) rings, limits the number of accessions that can be tested. Since low planting density and elevated [CO2] can both increase individual crop growth, I therefore hypothesized that cultivars capable of responding strongly to high [CO2] would also respond strongly to low planting density. To test this hypothesis, I grew four rice cultivars, previously determined to respond differently to elevated [CO2] in a 2-year FACE experiment, under normal and half-normal planting densities in a paddy field. The plant biomass was significantly increased (by 36-64%) by low planting density, with a significant cultivar×density interaction. Panicle number and grain weight showed similar responses. The change in grain weight caused by low planting density was closely, significantly (P<0.05), and positively correlated with the response to elevated [CO2] in the previous research. These results support the hypothesis that low planting density may emulate the effects of high [CO2] and therefore facilitate pre-screening of cultivars. © 2011 Elsevier B.V.

The present study analyzed the impact of earlier rice phenology as a result of climate change on the risk of cold damage during reproductive growth using the historical temperature record from 1961 to 2010 at four locations in northern Japan. During this period, heading date has become 0.7-1.9 days earlier per 10 years. Air temperatures during the booting stage (6-15 days before heading) decreased by 0.18 °C per 10 years even though the air temperature on a given calendar date has increased slightly. The estimated potential yield losses caused by cold damage have increased since the start of the study period. Thus, the advance in phonological events as a result of global warming is likely to increase the risk of future yield losses, and this has important implications for future adaptation strategies (breeding new cultivars and changing crop management strategies) to reduce the risk of cold damage. © 2011 Elsevier B.V.

Cronin A.L.,Iwate University
Behavioral Ecology and Sociobiology | Year: 2013

Coordination of group actions in social organisms is often a self-organised process lacking central control. These collective behaviours are driven by mechanisms of positive feedback generated through information exchange. Understanding how different methods of communication generate positive feedback is an essential step in comprehending the functional mechanisms underlying complex systems. The Japanese small-colony ant, Myrmecina nipponica uses both pheromone trails and an apparent quorum response during consensus decisions over a new home. Both of these mechanisms have been shown to generate positive feedback and are effective means of selecting among mutually exclusive courses of action. In this study, I investigate how pheromone trails and quorum thresholds contribute to consensus decisions during house-hunting in this species through experimental manipulations of pheromone trails, colony size and environmental context. Results demonstrate that (1) providing colonies with pre-established pheromone trails increased the number of ants finding the new site and led to higher quorum thresholds and more rapid relocations, (2) experimentally halving colony size resulted in a proportional decrease in quorum thresholds and (3) colonies relocating long distances had higher quorums than those relocating short distances. Taken together, these data indicate that pheromone trails are important for recruitment and navigation during nest site selection, but that decision making is contingent on a quorum response. Such synergy between mechanisms of positive feedback may be a common means of optimising collective behaviours. © 2013 Springer-Verlag Berlin Heidelberg.

Cronin A.L.,Iwate University
PLoS ONE | Year: 2013

Social animals can use both social and private information to guide decision making. While social information can be relatively economical to acquire, it can lead to maladaptive information cascades if attention to environmental cues is supplanted by unconditional copying. Ants frequently employ pheromone trails, a form of social information, to guide collective processes, and this can include consensus decisions made when choosing a place to live. In this study, I examine how house-hunting ants balance social and private information when these information sources conflict to different degrees. Social information, in the form of pre-established pheromone trails, strongly influenced the decision process in choices between equivalent nests, and lead to a reduced relocation time. When trails lead to non-preferred types of nest, however, social information had less influence when this preference was weak and no influence when the preference was strong. These results suggest that social information is vetted against private information during the house-hunting process in this species. Private information is favoured in cases of conflict and this may help insure colonies against costly wrong decisions. © 2013 Adam L.

Kaneiwa K.,Iwate University
Applied Soft Computing Journal | Year: 2011

In the area of data mining, the discovery of valuable changes and connections (e.g., causality) from multiple data sets has been recognized as an important issue. This issue essentially differs from finding statistical associations in a single data set because it is complicated by the different data behaviors and relationships across multiple data sets. Using rough set theory, this paper proposes a change and connection mining algorithm for discovering a time delay between the quantitative changes in the data of two temporal information systems and for generating the association rules of changes from their connected decision table. We establish evaluation criteria for the connectedness of two temporal information systems with varying time delays by calculating weight-based accuracy and coverage of the association rules of changes, adjusted by a fuzzy membership function. © 2010 Elsevier B.V. All rights reserved.

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