• Title/Summary/Keyword: Sex Ratio

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Reproductive Biology of the Purplish Washington Clam, Saxidomus prupuratus in the East China Sea (동중국해에 분포하는 개조개의 생식생물학적 연구)

  • Kim, Young-Seop;Kim, Yeong-Hye;Kim, Jon-Bin;Chang, Dae-Soo;Lee, Dong-Woo;Kang, Hyun-Jung
    • The Korean Journal of Malacology
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    • v.26 no.4
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    • pp.261-265
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    • 2010
  • Reproductive biology of the purplish Washington clam, Saxidomus purpuratus was investigated based on the samples captured in Jinhae Bay, the East China Sea from January to December 2002. The gonad index (GI) began to increase in January, reached the maximum value in March. The reproductive cycle of this species can be divided into five successive stages: the early active stage (from November to January), the late active stage (from December to February), the ripe stage (from February to May and October), the spawned stage (from May to December), and inactive stage (from November to December). The spawning period was from April to December, and the main spawning occurred between June and August. The shell length at 50% group maturity was estimated to be 71.85 mm. The Sex ratio of this species was not significantly different a 1:1 sex ratio (P > 0.05).

Fiber Yield and Sex Ratio of Hemp in Different Planting Density (대마의 재식밀도별 섬유수량 및 성발현 비율)

  • 권병선;정동희;문윤호;천종은
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.41 no.2
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    • pp.230-235
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    • 1996
  • This study was conducted to investigate the effects of planting densities on sex change and fiber yield in hemp plants, local variety 'Gangweonjong' was planted with various planting densities (40 $\times$ 5, 40 $\times$ 10, 40 $\times$ 20, 60 $\times$ 5, 60 $\times$ 10, 60 $\times$ 20cm), and harvesting dates (June 24, July 9 and 24). The stem length was the longest in the space of 60x20cm(8, 333 plants per l0a). The diameters of stem was the thickest in the planting space of 40 $\times$ 20cm(12, 500 plants per l0a) The ratio of peeled fiber yield was the highest in the planting space of 40$\times$5cm(50, 000 plants per l0a). In general, the condition under denser planting space (40 $\times$ 5cm ; 50, 000 plants per l0a) led to an increase in the number of female plants.

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Fisheries Biology of Swordtip Squid, Loligo edulis in Jeju Island, Korea (제주도 연안에 분포하는 창꼴뚜기(Loligo edulis)의 자원생물학적 연구)

  • Kang, Hyun-Jung;Kim, Yeong-Hye;Lee, Eun-Hui;Lee, Dong-Woo;Chang, Dae-Soo
    • The Korean Journal of Malacology
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    • v.25 no.1
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    • pp.23-28
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    • 2009
  • Samplings have been monthly collected in Jeju Island, Korea, using ser nets. A total of 759 individuals were sampled from June to November 2006. We analyzed mantle length distribution, monthly changes in maturity stages, maturation size and sex ratio. Mean Mantle length of the female specimens ranged from 6.7 to 50.3 cm and that of the male specimens ranged from 6.7 and 50.0 cm. The spawning period was November. The Mantle length at 50 % group maturity was estimated to be 17.1 cm. Sex ratio was 1 : 1.3 (male : female), suggesting the female population may be predominant.

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Growth and Sex Ratio of Juvenile Olive Flounder (Paralichthys olivaceus) at Different Size-ranks

  • Kim, Jong-Hyun;Kim, Hyun-Chul;Noh, Jae-Koo;Lee, Jeong-Ho;Kang, Jung-Ha;Kim, Kyung-Kil
    • Fisheries and Aquatic Sciences
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    • v.10 no.4
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    • pp.191-195
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    • 2007
  • The aim of this study was to assess whether size-rank at the juvenile stage is associated with growth performance and sex ratio in olive flounder (Paralichthys olivaceus). Juveniles (mean body weight, $8.8{\pm}0.9\;g$) were selected from two age groups, with the high size-rank group (HSRG) fish in the upper 19.3-67.3% of 104 days post-hatching (dph) age group and the low size-rank group (LSRG) fish in the lower 9.0-55.7% of 116 dph age group. Triplicate groups of 100 fish were reared over 32 weeks. A heavier final body weight was observed in the HSRG ($360{\pm}12\;g$) compared to the LSRG ($315{\pm}9\;g$, P<0.05), whereas no differences in feed intake, feeding efficiency, and mortality were seen between the experimental groups. The percentage of females was significantly higher in the HSRG (51.7%) than in the LSRG (30.8%, P<0.05). In addition, a remarkable increase in growth was recorded in females, indicating that the relative frequency of females increased with a body weight increase. The results suggest that high size-rank juvenile olive flounder have better growth performance and a higher percentage of females, because females start growing faster than males before size grading occurs.

Causes of Child Mortality (1 to 4 Years of Age) From 1983 to 2012 in the Republic of Korea: National Vital Data

  • Choe, Seung Ah;Cho, Sung-Il
    • Journal of Preventive Medicine and Public Health
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    • v.47 no.6
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    • pp.336-342
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    • 2014
  • Objectives: Child mortality remains a critical problem even in developed countries due to low fertility. To plan effective interventions, investigation into the trends and causes of child mortality is necessary. Therefore, we analyzed these trends and causes of child deaths over the last 30 years in Korea. Methods: Causes of death data were obtained from a nationwide vital registration managed by the Korean Statistical Information Service. The mortality rate among all children aged between one and four years and the causes of deaths were reviewed. Data from 1983-2012 and 1993-2012 were analyzed separately because the proportion of unspecified causes of death during 1983-1992 varied substantially from that during 1993-2012. Results: The child (1-4 years) mortality rates substantially decreased during the past three decades. The trend analysis revealed that all the five major causes of death (infectious, neoplastic, neurologic, congenital, and external origins) have decreased significantly. However, the sex ratio of child mortality (boys to girls) slightly increased during the last 30 years. External causes of death remain the most frequent origin of child mortality, and the proportion of mortality due to child assault has significantly increased (from 1.02 in 1983 to 1.38 in 2012). Conclusions: In Korea, the major causes and rate of child mortality have changed and the sex ratio of child mortality has slightly increased since the early 1980s. Child mortality, especially due to preventable causes, requires public health intervention.

Histologic Distribution of Pulmonary Tumors in Lebanon: A 5-Year Single Institution Experience

  • Kourie, Hampig Raphael;Rassy, Marc;Ghorra, Claude;Naderi, Samah;Kattan, Joseph
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.14
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    • pp.5899-5902
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    • 2015
  • Background: To compare the current histologic distribution of lung cancer in Lebanon to the worldwide trends, according to the 2004 WHO Classification. Materials and Methods: 1,760 patients with a pulmonary pathology examination at Hotel-Dieu de France University Hospital between July 2009 and July 2014 were included. Results: Some 676 out of the total investigated patients (38.4%) had a lung tumor. In 665 (98.4%) the tumors were malignant, with a mean age at diagnosis of 63.8 years and a male/female (M/F) sex ratio of 1.7:1. Among the malignant tumors, 86.2% were epithelial tumors with a mean age at diagnosis of 64.8 years and an M/F sex ratio of 1.9. Other malignant tumors consisted of metastatic tumors (10.2%), lymphoproliferative tumors (2.1%) and mesenchymal tumors (1.5%). Most common carcinoma subtypes were adenocarcinoma (48.0%), squamous cell carcinoma (23.0%) and small cell carcinoma (13.3%). Carcinoid tumors were the only carcinoma subtype with an M/F sex ratio below 1 (0.7). Salivary gland tumors were the carcinoma with lowest mean age at diagnosis (45.5 years). Conclusions: The histologic distribution of lung tumors in Lebanon is similar to that in developed countries. We believe this resemblance is due to common smoking habits, known to be responsible for the increase of lung adenocarcinoma at the expense of other subtypes.

The difference in the location of the malar summit between genders in Southeast Asians with appropriate references

  • Jirawatnotai, Supasid;Sriswadpong, Papat
    • Archives of Craniofacial Surgery
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    • v.22 no.2
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    • pp.78-84
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    • 2021
  • Background: Facial feminization surgery and malarplasty require information concerning facial features in the malar area. Such information varies as a function of sex and race. The objectives of this study aimed to quantitatively evaluate the location of malar prominence across sexes in the Southeast Asian population, and identify sex-specific differences in malar prominence using a combination of two-dimensional (2D) computed tomography (CT) and three-dimensional (3D) CT. Methods: The location of malar prominence was evaluated in 101 Thai adults, consisting of 52 men and 49 women. This study used both 2D CT and 3D CT to achieve greater accuracy, in which 2D CT was used to measure malar distance, malar summit width, facial width, and malar summitto-facial width ratio whereas 3D CT was used to evaluate the positional relationship between the zygomatic summit and four reference points of the zygoma. Results: The malar summit was positioned more laterally in males (p< 0.01) and was more projected in females (p= 0.01). The other 2D-parameters were wider in males. The ratio between the malar summit width and facial width showed similar results for both sexes. The vertical dimension did not show any statistically significant differences; however, a higher summit position was observed in males. Conclusion: The zygomatic summit is positioned more laterally in males and is more projected in females. However, the ratio was similar, which indicates that the male cranium is larger in size. Based on the results in this study, when facial feminization surgery or malarplasty is performed on a Southeast Asian patient, the malar bone should be reduced horizontally and moved forward for better outcomes.

Sexual Group Maturity and Main Spawning Period of Glyptocephalus stelleri (Teleostei: Pleuronectidae) (기름가자미 Glyptocephalus stelleri의 군성숙도와 주 산란기)

  • Shin, So Ryung;Kim, Hyeon Jin;Oh, Han Young;Lee, Jung Sick;Song, Hyejin;Kim, Jae Won
    • Journal of Marine Life Science
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    • v.7 no.1
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    • pp.37-44
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    • 2022
  • This study was performed to obtain information on the sex ratio, size at sexual group maturity, and main spawning period of Glyptocephalus stelleri. The sex ratio (female: male) was 1:0.54 (n=189:103, 64.7% female), and the frequency of females in the population tended to increase with total length. The oocyte development pattern was group synchronous development, in which oocyte groups at different stages were identified within the same ovary. The total length at 50% sexual group maturity was analyzed using a logistic regression model, and was determined to be 28.51 (female) and 30.49 cm (male). The gonadosomatic index (GSI) displayed the highest values in April (female) and March (male), and the main spawning period being in April to May.

Flower bud development and the influence of sex expression of summer pruning in Schizandra chinensis Baillon (오미자의 화아(花芽) 발달과 성 발현에 미치는 하계전정의 영향)

  • Kim, Sun;Kim, Tai-Su;Park, Moon-Soo;Park, Ho-Ki
    • Korean Journal of Medicinal Crop Science
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    • v.11 no.2
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    • pp.97-101
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    • 2003
  • The purpose of this experiment is to improve the ratio of female flower in Schizandra chinensis Baillon. The experiment was carried out in two purposes. One was to understand the development stages on bud formation and determining sex after bud formation by stage. The other was to investigate characteristics of flowers forming on spring when summer pruning was taken place in different cutting part and timing in S. chinensis Baillon. The outcome was that on 7th of June the flower bud was found next to leaf primordium in branch of this year and no changes were found in shape for two weeks by 26th July. On 26th of June, an ovule that forms organ was observed and then, an ovule was found after sex was determined on 6th of July. Second experiment was carried out to find out when the sex was determined by adapting different pruning methods; cutting the branch at 6th node on June 1, June 15, and July 1; cutting the branch at 10th node on June 15, and July 1. The result was that the re-growth ratio on the branch 6th node was cut on June 1 and June 15. July 1 was 34-56% and, however, the number of setting flowers and mail flowers were fewer than the normal branches. More over, even though the re-growth ratio of branches were 34-25% when the cutting was taken place at 10th node on June 15 and July 1, the number of setting flowers and mail flowers were the same as the non treated branch. As a result, it is assumed that cutting controlling in this plant to increase the number of female flowers has no effect.

SEX RATIOS OF NATURAL POPULATION OF IXODID TICKS IN PASTURE GROWN IN BANGLADESH

  • Giasuddin, M.;Haq, M.M.;Mondal, M.M.H.;Sarker, N.R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.8 no.6
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    • pp.647-650
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    • 1995
  • The study on the sex ratios of natural population of Ixodid ticks in pasture was conducted in the Bangladesh Agricultural University Campus, Mymensingh, from 1988 to June 1990. The samples were collected from the five grazing fields consisting of five different vegetations. Dragging methods were used for the collection of samples. In 24 months of observations a total of 1113 ticks of two different species, Boophilus microplus (670), Haemaphysalis bispinosa (443) were collected and their sex ratio was determined. Females were recorded higher in both B. microplus and H. bispinosa.