• Korean Journal of Environmental Biology
• /
• v.22 no.2
• /
• pp.321-328
• /
• 2004

The effects of Di (2-ethylhexyl) phthalate (DEHP) on the fourth instar larvae of Chironomus riparius were tested in the laboratory. Employing a waterreplacement exposure setup, chironomids were subjected to various concentrations. In the most treatments mortality reached a statistically significant difference from the control conditions. As DEHP concentrations were increased, the rates of emerged adults decreased. Sex ratio was unaffected with little deviation from a 1:1 relationship (except in 1 and $30\mu{g}\;L^{-1})$. The developmental stages was delayed at low concentration (0.3 and $1\mu{g}\;L^{-1})$. Generally the emergent period was different between males and females, and the first emergent day of males was faster than females. The body shape of female adults was larger than males. Differences between males and females were found in body volume, body length and body width. In addition, the body volume showed the significant difference between controls and treatments, and those especially well observed females.

• Fisheries and Aquatic Sciences
• /
• v.14 no.2
• /
• pp.111-117
• /
• 2011

The population dynamics of Pandalus gracilis was investigated in the southeastern coastal area of Korea between May 1998 and April 2000. Of the 4,127 specimens, 57% were identified as females, 39% as males, and 4% as transitional hermaphrodites. The number of females was greater than that of males and transexuals. A significant correlation was observed between the number of transitional hermaphrodites and ambient seawater temperature. Growth parameters were estimated using the modified von Bertalanffy growth function model incorporating seasonal variation in growth using the program ELEFAN. Females grew faster and reached a larger size-at-age than males (K=0.65/y and $L_{\infty}$=17.86 mm carapace length [CL] for females; K=0.51/y and $L_{\infty}$=14.70 mm CL for males). Mean size and age (95% confidence limits) at sex transition, calculated from growth parameters, were 7.07 mm carapace length and 1.05 years, respectively. The reproductive strategies of pandalid shrimps are discussed in terms of the type of sex transition.

• Speech Sciences
• /
• v.10 no.3
• /
• pp.103-116
• /
• 2003

This study examines whether gender influences voice cessation time (voicing duration) of lax (voiced) obstruents. Females more frequently show a posterior glottal opening throughout a vibratory cycle and have larger open quotients and less vocal fold contact than males. The gender differences imply that females can yield less voicing in their speech. In line with this, we hypothesized that the male voice is more voiced than the female voice in intervocalic lax (voiced) obstruents. This hypothesis was supported by the results of the present experiment, i.e., males exhibited significantly longer voicing and higher percentage of voicing relative to consonant duration than females during the intervocalic lax obstruents /p, t, k, c/ of Korean. Based on the results and the literature review, it is further hypothesized that the vocal folds are more likely adducted for males while abducted for females. The experimental data also indicated that males speak faster than females.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.910
• /
• pp.1320-1328
• /
• 2004

Purposes of the study were to find out the joint effects of two salient appearance cues-hair colors and hair lengths on males fashion images, using 729 university students in Daejon city and a Chungnam province. The study was a quasi experiment; the dependent variables were hair lengths(4 levels) and hair colors(4 levels)and the dependent variable was a set of semantic different of scales which was consisted of 40 hi-polar adjectives, The data were analyzed by a factor analysis, 3-way ANOVA, and the results were as follows. Hair lengths effected on the image of five dimensions, salient, social, potency, evaluate and dynamics while hair colors effected on salients, social and potency dimensions. The most significant interaction effect between hair color and lengths were existed on the salient image: For the longer haired males, the color effects became less evident then normal to shorten haired males and it can be concluded that when two salient cues were combined one cue's effect became discounted.

• Preventive Nutrition and Food Science
• /
• v.8 no.4
• /
• pp.401-405
• /
• 2003

This study was conducted to find gender differences in physical activity, dietary habit and nutrient intake in 4∼6th grade students in elementary school. Physical activity assessment showed that males significantly engaged in more vigorous activity with longer duration than females. It was found that females skipped their breakfast more often and had more snack than males. On the other hand, males were more indulged in peaky eating, despite their good practice of drinking milk. Twenty-four hour dietary recall revealed that energy intakes in both males and females were not sufficient. Furthermore, subjects, regardless of gender, consumed marginal intakes of Ca and Fe. Special attention should be given to marginal intakes of Ca in the subjects. Due to low Fe intake in females, more caution should be taken to include a meal which can enhance iron absorption. It might be suggested that effective intervention strategies need to be developed and implemented to choose nutrient dense foods and activities that lead to better health.

• Journal of the Korean Home Economics Association
• /
• v.40 no.7
• /
• pp.157-172
• /
• 2002

The purpose of this study is to characterize body types of males in their twenties, and to provide information on body types of males by classifying them into groups. In addition, this study attempts to provide ways that can help improve the fit and coverage rate of ready-to-wear clothes by developing an apparel sizing system according to body types. 297 male subjects in their twenties participated in this study. 54 anthropometric and 35 photographic measurements were taken from each subject. After combining the body types of the front and the side into a whole body, we selected typical body types out of the combinations. It is shown that 84.64% of males in their twenties belong to the HI type, H/equation omitted/ type, X/equation omitted/ type, Xl type, Yl type, and HS type. To develop a new size system of clothes, the distribution of sizes was determined by using means and standard deviations for basic parts of each body type. Then, the most optimal sizes were selected separately for each body type to maximize the coverage rate.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.31 no.2 s.161
• /
• pp.308-318
• /
• 2007

This study aims to survey the satisfaction level with the fit of ready-made suits(jackets and pants) among adult males and thereby to show its differences by the age group and body type. The respondents to the questionnaire survey were 465 males, aged 20 through 59 years. The conclusions are as follows: 1. The average satisfaction level for the fit of each item ranged from 2.65 to 3.57, with the higher level found in jackets than in pants, and also in circumference parts than in length parts 2. The satisfaction level for the fit by the age of adult males showed inter-group differences in the parts of jacket length, sleeve length, shoulder width, sleeve openings, and sleeve band width for jackets; and pant length of pants. 3. The satisfaction level for the fit by the body type of adult males indicated into-group differences in chest circumference of jackets only. 4. The satisfaction level for the fit, with the exclusion of the age and body type relationship showed that adult males are affected more by the age than by the body type. 5. In the repair frequency by the item, pants(45.6%) showed a higher level than jackets(24.7%). The parts with a high repair level by the item were jacket length(8.4%) and steeve length(19.8%) for jackets; and pant length(42.4%) and waist circumference(8.4%) for pants.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.23 no.3
• /
• pp.273-286
• /
• 2013

Objectives: The present study was conducted in order to investigate the reproductive toxicity in rats exposed to 1,4-dichlorobutane. Methods: The test chemical was administered orally at 0, 8.3, 50 and 300 mg/kg/day. Males were administered daily for 10 weeks prior to the mating period. Females were administered from between two weeks before mating to the 21stday of lactation. Results: In both sexes, a decrease in body weight and an increase in the weights of the liver and kidneys were observed. In males, discoloration of the liver, hepatocyte hypertrophy and mineralization in the kidneys were observed. In females, animal deaths, dystocia and pup deaths due to maternal dysfunction were observed. In F1 animals of both sexes, a decrease in body weight was observed at 300 mg/kg/day. An increase in the weights of the liver in both sexes, mineralization in the kidneys of males, animal deaths, hepatocyte hypertrophy and pup deaths due to maternal dysfunction were observed at 50 mg/kg/day. Mineralization in the kidneys of males was observed at 8.3 mg/kg/day. Therefore, the no-observed-adverse-effect levels (NOAELs) of 1,4- dichlorobutane were considered to be under 8.3 mg/kg/day for males, 8.3 mg/kg/day for females, more than 300 mg/kg/day for fertility in both sexes, 8.3 mg/kg/day for maternal functions and 50 mg/kg/day for F1 offspring. The absolute toxic dose was believed to be 8.3 mg/kg/day for males, 50 mg/kg/day for females, 50 mg/kg/day for maternal functions and 300 mg/kg/day for F1 offspring. However NOAEL for fertility could not be determined since there were no treatment-related changes. Conclusions: Under the present experimental conditions, 1,4-dichlorobutane is a Category 1B Reproductive Toxicant (presumed human reproductive or developmental toxicant).

• Development and Reproduction
• /
• v.20 no.3
• /
• pp.267-274
• /
• 2016

Cichlid fish species exhibit characteristic sexual behaviors according to not only reproductive stages but also social status. In a reproductive season, Astatotilapia burtoni males compete for females and a small number of dominant winners finally obtain the chance of spermiation. In addition to the characteristic behaviors, the dominant males have relatively bigger gonadotropin-releasing hormone 1 (GnRH1) neurons in the preoptic area (POA) of brain compared to those of subordinate males. Although the stimulatory effect of GnRH1 in vertebrate reproduction is well established, little is known about the triggering signal pathway to control GnRH1 neurons and GnRH1-mediated sexual behavior. In the present study, we evaluated the potential effect of TOR inhibitor rapamycin in relation to the cichlid male behaviors and GnRH1 neuron. After 14 h and 26 h of intraventricular injection of rapamycin, behavior patterns of chasing and courtship display did not show significant changes between rapamycin- and DMSO-injected males. Behaviors of spawning site entry increased in rapamycin-injected fish at 26 h post-injection than at 14 h post-injection significantly (P<0.05). Meanwhile, there was a tendency that GnRH1 neurons' soma size in the POA shrank by rapamycin injection, whereas the testes did not show notable changes. Taken together, these results suggest the possible role of TOR signal on GnRH1-mediated sexual behavior in cichlid dominant males, although further biological characterization of the TOR signaling pathway will be required to clarify this matter.

• Journal of Ecology and Environment
• /
• v.31 no.3
• /
• pp.183-191
• /
• 2008

To determine the age structure of a Hynobius leechii breeding population and analyze relationships between the order of entrance to breeding ponds and physical parameters and age, we studied a wild population of the species in the Research Forests of Kangwon National University in Chuncheon, Kangwon, South Korea from March 16 to April 13, 2005. The age of breeding males ranged one to nine years old and that of females ranged from three to nine years old. The asymptotic sizes of males and females were 6.36 and 6.51 cm, respectively, and the growth coefficients of males and females were 0.71 and 0.81, respectively. The snout-vent length (SVL), head length, and body mass of males were all positively correlated with their age, but female age did not show a significant relationship with any physical parameter. The tail depth, body mass, and condition factors (SVL/body mass $\times$ 100) of both males and females were negatively related with the order of entrance to the breeding pond. The head width and SVL of males were also negatively correlated with the order of entrance, but the SVL of females was positively related with the order of entrance. These results suggest that physical parameters are more important determinants of breeding migration patterns than age. We discuss which of two hypotheses, the mate opportunity hypothesis and the susceptibility hypothesis, is better able to explain the order of entrance to breeding ponds for male and female H. leechii.