Structural dynamics and divergence of the polygalacturonase gene family in land plants

A distinct feature of eukaryotic genomes is the presence of gene families. The polygalacturonase (PG) (EC3.2.1.15) gene family is one of the largest gene families in plants. PG is a pectin-digesting enzyme with a glycoside hydrolase 28 domain. It is involved in numerous plant developmental processes. The evolutionary processes accounting for the functional divergence and the specialized functions of PGs in land plants are unclear. Here, phylogenetic and gene structure analysis of PG genes in algae and land plants revealed that land plant PG genes resulted from differential intron gain and loss, with the latter event predominating. PG genes in land plants contained 15 homologous intron blocks and 13 novel intron blocks. Intron position and phase were not conserved between PGs of algae and land plants but conserved among PG genes of land plants from moss to vascular plants, indicating that the current introns in the PGs in land plants appeared after the split between unicellular algae and multicelluar land plants. These findings demonstrate that the functional divergence and differentiation of PGs in land plants is attributable to intronic loss. Moreover, they underscore the importance of intron gain and loss in genomic adaptation to selective pressure

Numerical Analysis of Saturated Sand Under Dynamic Loads

In this study, the behavior of reclaimed soils including the effects of excess pore water pressure and the loss of strength under dynamic loads or earthquakes are investigated and simulated. The constitutive model based on the disturbed state concept (DSC) is introduced and DSC-DYN2D program is utilized in a numerical analysis. In the laboratory test, quasi-static and cyclic triaxial tests were carried out to determine parameters for the numerical analysis. Field tests were executed in Inchon International Airport with a 10 tons hydraulic hammer. In the field test, the data of dynamic loads and excess pore water pressure were measured using a 3-D geophone and a pressure transducer respectively, The data of field tests showed the accumulation of excess pore water pressure when rapid dynamic loads were applied. Especially, a back-prediction program based on DSC model is developed and verified its accuracy using various parameters from the cyclic triaxial test. As the results of numerical simulation, the predicted trends for excess pore water pressure compare well with the observed data. Based on the result of this research, it is found that the numerical analysis based on the DSC model is compatible to predict the softening behavior of saturated reclaimed soils under dynamic loads

POE Research on the Role and Effect of Landscape Design Supervision in the Creation of Large Parks: Gwanggyo Lake Park

While pursuing rapid urbanization and industrialization, the Korean government has also endeavoured to create large scale urban parks. Despite the number of large parks having increased, issues regarding their quality have been consistently raised. Noteworthy, is the quality of Gwanggyo Lake Park, which has been positively evaluated by landscape experts and citizens, and the introduction of a landscape design supervision system is thought to be one of the important reasons for this evaluation outcome. This study conducts a post-evaluation of the role and effect of landscape design supervision on the process of creation of the park. Open interviews were conducted with five staff who participated in the design and construction of the park. As a result of the study, a landscape design supervisor was defined as the second designer, because the supervisor not only monitored whether the construction complied with design, but also played multiple roles in understanding the designer\u27s concept and intention. The landscape design supervisor also responded to the current conditions of the construction site, which included variables and professional opinions from different entities, thereby establishing and producing the most efficient and reasonable alternatives. The landscape design supervisor plays a role in communicating between the public and construction teams. The landscape design supervisor helped maintain the concept and identity of the initial design of the park, raise its overall quality, and implement a design that reflects the special characteristics of the place. It also helped raise landscape designers\u27 self-esteem and sense of happiness by properly reflecting their original design intentions in the construction. This study is an initial research for a post-evaluation using the method of interviewing, which is meaningful as an initial study to analyse the role of landscape design supervisors. It will contribute to future large park projects and the introduction of the landscape design supervision system in them

Mechanical Alloying Synthesis and Spark Plasma Sintering Consolidation of Al-Ti-Si-W Alloys

Al-Ti-Si-W quaternary powders were mechanically synthesized by planetary ball milling; and further consolidated by spark plasma sintering. The nominal compositions of the quaternary alloys were designed to be Al60Ti30Si5W5 and Al45Ti40Si10W5 (wt.%). The microstructural evolution of intermetallic compounds in Al-Ti-Si-W alloys included titanium aluminide, titanium silicide, and ternary alloys (AlxTiy, TixSiy, and TixAly,Siz), whereas W was embedded in the Al-Ti matrix as a single phase. The phase composition and grain size distribution were investigated using electron backscatter diffraction analysis, in which refined and uniform microstructures (less than 0.3 μm) were attributed to severe plastic deformation and rapid densification of the pre-alloyed powders. The mechanical properties were correlated with the Al content in the quaternary alloys; a high hardness of 1014.6 ±73.5 kg/mm2 was observed