Identification of Albula sp. (Albulidae: Albuliformes) Leptocephalus Collected from the Southern Coastal Waters of Korea using Cytochrome b DNA Sequences

A single specimen ofAlbula leptocephalus (55.7 mm SL) was collected from the southern coastal waters of Korea using an aquatic lamp. It is characterized by having a ribbonlike body with a small head and a well-forked caudal fin. Although the general appearance was similar to the leptocephalus ofA. vulpes including myomere counts and fin ray counts, the melanophore deposition was different from that ofA. vulpes. This leptocephalus specimen was confirmed withA. forsteri using the cytochrome b mtDNA (Cytb) analysis. The genetic distance ofCytb between the present leptocephalus andA. forsteri is 0.006-0.038, which falls into the cutoff point separatingAlbula species into eight deep lineages including the four valid species. Its genetic characteristic have more similarities to those of Fiji than those of Hawaii and the Northern territory of Australia.     

Ultimate load capacities of mooring bollards and hull foundation structures

CSRs (Common Structural Rules for bulker and tanker), which came into effect in 2006, invoke the concept of the ultimate strength of hull girders. While numerous studies associated with the ultimate capacities regarding global hull girders and stiffened panels have been carried out, there are few application cases of the ultimate strengths for deck machineries and their supporting structures. In the present study, nonlinear finite element analyses have been performed to obtain ultimate capacities for a size 450 DIN type bollard including hull foundation structures for which elastic strength assessments based on allowable stress analyses were jointly carried out by a Mooring Fitting SWL Standardization Committee consisting of four major Korean shipbuilders (DSME, HHI, HHIC, and SHI) in 2003. The plastic hardening property is identified from a comparison of the results of ultimate strength simulations and a bollard tension tests performed by the committee. It is assumed that the ultimate load is the corresponding load point when the deformation slope of the bollard column reaches the critical slip angle. It is concluded that the reinforcements appear to be effective with respect to the allowable stress criterion, but are not substantially effective from the point of view of ultimate capacities. In other words, structural reinforcements based on allowable stress analyses may noticeably increase production costs, but do not remarkably raise the ultimate capacities.     

Reproduction of the giant jellyfish, <Emphasis Type="Italic">Nemopilema nomurai</Emphasis> (Scyphozoa: Rhizostomeae), in 2006–2008 as peripherally-transported populations

This study investigated the sexual maturation process, release of spermatozoa or eggs and oocyte diameter of the rhizostomid medusae Nemopilema nomurai using samples collected from August 2006 to June 2008 from the waters around Korea and Japan, including peripheral areas outside the species’ usual habitat. Immature medusae were observed from June to October only in the western sector of the study area. The onset of spermatozoa and egg release occurred in September and October, respectively, and peaked in December and January. Medusae migrated eastward from source areas with the Tsushima Warm Current, where they formed gametes and spawned. Peak position and maximum oocyte diameter increased as the gonads developed according to the size-frequency distribution of oocytes. No fertilized eggs or embryos were found in the gonads. The correlation was analyzed with bell diameter, maximum oocyte diameter, sampling date, surface water temperature and gonad color to estimate which environmental factors and maturation indices were related to the maturation stage of females. Maturation stage correlated well with maximum oocyte diameter, which correlated negatively with surface water temperature. There was no significant correlation between bell diameter and maturation stage. Therefore, bell diameter was inappropriate for determining maturation index. Sex could not be distinguished clearly by gonad color. However, light pink gonads were more prevalent in males and various deep colors such as orange and brown were more frequent in female medusae.     

Influence of frequency‐dependent soil–structure interaction on the fragility of R/C bridges

Bridge performance under earthquake loading can be significantly influenced by the interaction between the structure and the supporting soil. Even though the frequency dependence of the interaction mentioned in this study has long been documented, the simplifying assumption that the dynamic stiffness is dominated by the mean or predominant excitation frequency is still commonly made, primarily as a result of the associated numerical difficulties when the analysis has to be performed in the time domain. This study makes use of the advanced lumped parameter models recently developed 1 in order to quantify the impact of the assumption on the predicted fragility of bridges mentioned in this study. This is achieved by comparing the predicted vulnerability for the case of a reference, well studied, actual bridge using both conventional, frequency‐independent, Kelvin–Voigt models and the aforementioned lumped parameter formulation. Analysis results demonstrate that the more refined consideration of frequency dependence of soil–structure interaction at the piers and the abutments of a bridge not only leads to different probabilities of failure for given intensity measures but also leads to different hierarchy and distribution of damage within the structure for the same set of earthquake ground motions even if the overall probability of exceeding a given damage state is the same. The paper concludes with the comparative assessment of the effect for different soil conditions, foundation configurations, and ground motion characteristics mentioned in this study along with the relevant analysis and design recommendations. Copyright © 2016 John Wiley & Sons, Ltd.     

Density Estimates of Moon Jellyfish (Aurelia coerulea) in the Yeongsan Estuary using Nets and Hydroacoustics

Ocean Science Journal - Using nets and acoustic frequencies of 38 and 120 kHz, we estimated the density distribution of the moon jellyfish, Aurelia coerulea, in the Yeongsan Estuary, where a large...     

Chelonodontops bengalensis (Tetraodontiformes: Tetraodontidae): A New Species of Puffer Fish from the Northern Bay of Bengal Based on Morphology and DNA Barcode

Ocean Science Journal - The new puffer fish species Chelonodontops bengalensis (Pisces: Tetraodontidae) is described from two specimens collected on the southwest coast of the Bay of Bengal,...     

Protective effects of Ecklonia cava extract on the toxicity and oxidative stress induced by hair dye in in-vitro and in-vivo models

Oxidative hair dyes containing p-phenylenediamine(PPD) are reported to induce an allergic reaction by promoting oxidative stress when absorbed through the skin. Despite the associated risk, these hair dyes remain popular owing to their convenience and sharpness of color. This makes it important to minimize the cytotoxicity and oxidative stress induced by PPD-containing hair dyes. Ecklonia cava extract has been evaluated in different studies for its protective effects against external stress in fibroblasts and keratinocytes. Our study was aimed at using in-vitro and in-vivo models to investigate the extract's effects on cytotoxicity of and oxidative stress induced by PPD-containing hair dyes. Analysis of CIEL*a*b* Color space was first used to determine the range of E. cava extract that would not interfere with the coloring ability of the dye upon addition. Subsequently, the set ranges of E. cava extract(5% and 7%) were added to the hair dye and their toxicity assessed by evaluating the viability of fibroblasts and keratinocytes. The effects on developmental phenotypes and induction of oxidative stress by hair dye were evaluated and compared with those of hair dyes containing different contents of E. cava extract using an in-vivo zebrafish model. Our results showed that E. cava extract in hair dye could significantly decrease the cytotoxicity and levels of oxidative stress caused by hair dyes containing PPD in both in-vitro and in-vivo models.These results suggest that the addition of 7% E. cava extract to 250 μg/mL hair dye does not interfere with the coloring ability of the dye while showing significant protective effects against the hair dye. The study proposes that the use of E. cava extract as an adduct to hair dyes containing PPD reduces the cytotoxicity and oxidative stress induced by these hair dyes.     

Experiments on vision guided docking of an autonomous underwater vehicle using one camera

This paper introduces an underwater docking procedure for the test-bed autonomous underwater vehicle (AUV) platform called ISiMI using one charge-coupled device (CCD) camera. The AUV is optically guided by lights mounted around the entrance of a docking station and a vision system consisting of a CCD camera and a frame grabber in the AUV. This paper presents an image processing procedure to identify the dock by discriminating between light images, and proposes a final approach algorithm based on the vision guidance. A signal processing technique to remove noise on the defused grabbed light images is introduced, and a two-stage final approach for stable docking at the terminal instant is suggested. A vision-guidance controller was designed with conventional PID controllers for the vertical plane and the horizontal plane. Experiments were conducted to demonstrate the effectiveness of the vision-guided docking system of the AUV.     

Naturalization of Landscaping Woody Plant,Magnolia obovata Potentially Invasive Species

Magnolia obovata, a tree species native to Japan, is a traditional landscaping tree that has also been introduced to various countries. M. obovata individuals have recently emerged in non-planting areas in Korea, prompting us to investigate its distribution by establishing Dosolsan in an urban forest of Daejeon City as the target site. In order to determine its naturalization, the study explored the status of population growth by examining the diameter at breast height of the individuals, and diameter diminution quotient was calculated. Cores of the trees were collected, and the age distribution was estimated by regression analysis. Reproduction possibility was analyzed by verifying the flowerblooming and fruit-bearing. Spontaneous colonization was investigated in the other potential sites which have different location and environment, respectively.The diameter distribution showed a reverse J-shaped curve, and the diminution quotient was ≥ 1.8. The population was composed of different generations,thus confirming the growth of the population. The distributed M. obovata grew and flowered normally,and followed a normal life cycle. The same phenomenon was observed in other planting areas,residual forests in urban or rural areas, alluvial islands, and mountain forests. The continuous spread of M. obovata in new ecosystems may be attributable to its long-term distribution by birds, relatively fast growth, and maturity time. Investigations on the naturalization and spread of M. obovata in Korea, as well as in various countries, are warranted.