Dependence of reaction center-type energy-dependent quenching on photosystem II antenna size

AbstractThe effects of photosystem II antenna size on reaction center-type energy-dependent quenching (qE) were examined in rice plants grown under two different light intensities using both wild type and qE-less (OsPsbS knockout) mutant plants. Reaction center-type qE was detected by measuring non-photochemical quenching at 50 μmol photons m−2 s−1 white light intensity. We observed that in low light-grown rice plants, reaction center-type qE was higher than in high light-grown plants, and the amount of reaction center-type qE did not depend on zeaxanthin accumulation. This was confirmed in Arabidopsis npq1–2 mutant plants that lack zeaxanthin due to a mutation in the violaxanthin de-epoxidase enzyme. Although the electron transport rate measured at a light intensity of 50 μmol photons m−2 s−1 was the same in high light- and low light-grown wild type and mutant plants lacking PsbS protein, the generation of energy-dependent quenching was completely impaired only in mutant plants. Analyses of the pigment content, Lhcb proteins and D1 protein of PSII showed that the antenna size was larger in low light-grown plants, and this correlated with the amount of reaction center-type qE. Our results mark the first time that the reaction center-type qE has been shown to depend on photosystem II antenna size and, although it depends on the existence of PsbS protein, the extent of reaction center-type qE does not correlate with the transcript levels of PsbS protein. The presence of reaction center-type energy-dependent quenching, in addition to antenna-type quenching, in higher plants for dissipation of excess light energy demonstrates the complexity and flexibility of the photosynthetic apparatus of higher plants to respond to different environmental conditions

Performance Analysis and Assessment of BIM-Based Construction Support with Priority Queuing Policy

A variety of methodological approaches have been developed to performance assessment for the adoption of building information modeling (BIM) at organizational and project levels. Recently, active research has been undertaken on the quantitative analysis of the effects of BIM on projects through BIM-based design validation methodologies. Nevertheless, few studies have addressed the interactions between the BIM staff providing BIM services and the project participants requesting BIM services from the viewpoint of micro-level management. In this study, with the aim of improving the performance of BIM-based construction support, we performed an analysis of the properties of the BIM request for information (RFI) in the construction phase, proposing a method for performance analysis and assessment which considers the competencies of the BIM staff that handle and process such requests. This study verified that, through the application of a priority policy according to the purpose of the information use in the construction phase, the performance of the BIM staff can be improved, and the waiting time of project participants to receive responses to the BIM RFIs can be reduced. The findings of this study are expected to be applied in areas such as decision making on allocation of BIM staff and analysis of return on investment (ROI) in hiring BIM services

Phased Reverse Engineering Framework for Sustainable Cultural Heritage Archives Using Laser Scanning and BIM: The Case of the Hwanggungwoo (Seoul, Korea)

This study proposed a phased reverse engineering framework to construct cultural heritage archives using laser scanning and a building information model (BIM). This framework includes acquisition of point cloud data through laser scanning. Unlike previous studies, in this study, a standard for authoring BIM data was established through comparative analysis of existing archives and point cloud data, and a method of building valuable BIM data as an information model was proposed. From a short-term perspective, additional archives such as member lists and drawings can be extracted from BIM data built as an information model. In addition, from a long-term perspective, a scenario for using the cultural heritage archive consisting of historical records, point cloud data, and BIM data was presented. These scenarios were verified through a case study. In particular, through the BIM data building and management method, relatively very light BIM data (499 MB) could be built based on point cloud data (more than 917 MB), which is a large amount of data