• Honam Mathematical Journal
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• v.36 no.1
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• pp.131-139
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• 2014

We present a theoretical study that assesses the persistence of obesity. The basic reproductive number for the model is computed, and its sensitivity on some parameter values is explored. This may be of interest to public health authorities.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1073-1088
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• 2010

In this article we want to formulate a disease transmission model, MSEIR model, for a population with individuals travelling between patches i and i + 1 and we derive an explicit formula for the basic reproductive number, $R_0$, employing the spectral radius of the next generation operator. Also, in this article we show that a system of ordinary differential equations for this model has a unique disease-free equilibrium and it is locally asymptotically stable if $R_0$ < 1 and unstable if $R_0$ > 1.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.4
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• pp.144-152
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• 2012

Objective: Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats. Methods: Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood. Results: Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150. Conclusion: It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

• Reproductive and Developmental Biology
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• v.34 no.1
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• pp.27-32
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• 2010

This study was conducted to estimate the effect of the breed, sire-breeds, farrowing year, farrowing season and parity on number of born alive (NBA), number of weaning (NW) and survival rates of weaning (SRW) in swine. The data were obtained from 46,704 litters of the Landrace, Yorkshire, Duroc and Cross breed farrowed from 1996 to 2005 at 142 GP are registered in Korean Animal Improvement Association (KAIA). There was highly significant effect of breed, sire breed, farrowing year, farrowing season and parity on NBA, NW, SRW (p<0.01). The result of this study could be available to genetic improvement of reproductive traits as a basic reference in Korean pig industry. To achieve the more effective improvement of reproductive traits, additional research such as genetic parameter evaluation should be performed.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.161-168
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• 2015

The epidemic is seemed to be extremely difficult for accurate predictions. The new models have been suggested that show quite different results. The basic reproductive number of epidemic for consequent time intervals are estimated based on stochastic processes. In this paper, we proposed a transmission distribution estimation for Ebola virus disease epidemic model. This estimation can be easier to obtain in real time which is useful for informing an appropriate public health response to the outbreak. Finally, we implement our proposed method with data from Guinea Ebola disease outbreak.

• Journal of Embryo Transfer
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• v.29 no.2
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• pp.189-194
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• 2014

The reproductive disorders are the major causes of reproductive infertility in cows that affect the total annual calf crop, resulting in great economic loss in Bangladesh. The aim of the study was to find out the reproductive disorders (RD) in dairy cows that markedly influences the reproductive performances in aspect of Bangladesh. A total number of 1658 dairy cows were selected according to their body condition score (BCS) in different farms at the southern part of Bangladesh during the period of 2011 to 2012. The preliminary data (basic information) were collected directly from the dairy farmer's record books and asking questions according to a prescribed questionnaires as well as the diagnosis of RD was presumptively confirmed on the basis of history, clinical signs and examination of animals by ultrasonography and others necessary tools. There are thirteen major reproductive disorders were identified. Overall prevalence of reproductive disorders at that area were 23%, among of these anoestrus 5.1%, repeat breeder 3.7%, metritis 4.4%, poor heat detection 1.6%, ovarian cyst 0.36%, retain placenta 4.6%, dystocia 0.97% and pyometra 0.24%. It is indicated that anoestrus and retention of placenta after calving was most hazardous cause of infertility whereas the metritis and repeat breeder were the second line of consequence. RD had shown significantly higher incidence in low BCS (${\leq}2$) than that of fair (2.5) and very good (${\geq}3{\sim}3.5$). In conclusion, the highest RD especially anoestrus and retention of placenta is very alarming for reproductive loss which might be needed further research to identify the specific cause of these disorders for establishment a profitable dairying and dairy population.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.73-80
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• 2020

Polygonatum stenophyllum Maxim. is a native perennial herb to Korea belonging to family Liliaceae. Although it was removed from the endangered species list, since it inhabits the riverside, it has been threatened with damage to its populations due to frequent disturbances. In order to reveal the basic ecological characteristics of P. stenophyllum, This study was identified the life cycle of the aboveground part and was measured the number of flowers and fruits, which are reproductive organs of P. stenophyllum in riverside in Paju - si during the two years. As a result, aboveground part of P. stenophyllum appeared and grew rapidly until the end of May to about 1m. In early May, two buds per one peduncle were formed up to six pairs per floor. The flowers bloomed in turn from the base of the stem and to the top floor and the blooming occurred when the number of leaves was at least three. Fruits were formed in mid-June and matured by the end of September. The numbers of flowers and fruits were revealed that flowers bloomed in turn from the bottom of the stem to the top floor, the most intensively bloomed in the center part of the stem, and did not bloom from the floor closest to the ground and above the highest 5th node. This basic ecological characteristics of the P. stenophllyum grown in riverside identified in this study will be useful as basic data for their conservation.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.369-378
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• 2016

Improving the reproductive traits of Hanwoo might decrease their production cost. Therefore, this study was conducted to investigate the effects of environmental factors [registration grade (basic, pedigree or advanced), birth year, birth season, parity, delivery year, and delivery season] on various reproductive traits (age at 1st service, age at 1st conception, age for 1st calving, days at 1st service postpartum, non-pregnant condition period, calving interval, gestation length, and number of services for conception) in Hanwoo (primiparous 12,219 heads, multiparous 10,471 heads). All data was acquired from Gyeongnam province areas which were surveyed from 2007 to 2015. All environmental factors significantly influenced (p < 0.01) reproductive traits of primiparous cows but, but not all environmental factors influenced multiparous cows. Primiparous cows registered as advanced grade showed significantly lower age at 1st service (by 15.36 days), age at 1st conception (by 8.66 days), and age for 1st calving (by 8.77 days) (p < 0.01) than those registered as basic grades. Age at 1st service, age at 1st conception and age for 1st calving were not significantly related to birth year in primiparous cows. As delivery years advanced from 2005 to 2012, all durations associated to reproductive traits tended to be shorter. Days at 1st service postpartum, non-pregnant condition period, and calving interval tended to be shortened as parity increased. Days at 1st service postpartum, days open, calving interval, and gestation in multiparous cows calved in winter were shorter than those in summer. The registration grade was not a effected with reproductive traits in Hanwoo.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.14 no.1
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• pp.1-16
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• 2010

An epidemic model with Classical Kermack-Mckendrick incidence rate under a limited resource for treatment is proposed to understand the effect of the capacity for treatment. We have assumed that treatment function is strictly increasing function of infective individuals and becomes constant when the number of infective is very large. Existence and stability of the disease free and endemic equilibrium are investigated, boundedness of the solutions are shown. Even in this simple version of the model, backward bifurcation and multiple epidemic steady states can be observed with some sets of parameter values. Hopf-bifurcation analyses are given and numerical examples are provided to help understanding.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.177-182
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• 2020

The present study aimed to investigate the conceptus-related changes during early pregnancy in the Black Bengal breed of goat. A total of 22 gravid genitalia of the Black Bengal goats were collected from local slaughterhouses. The crown-rump lengths (CRL) of the conceptuses were determined to estimate the gestational age (GA). The length and diameter of uterine horn and amniotic sac were measured, and volume of amniotic and allantoic fluid formed by individual conceptus were recorded. The results reveal that the CRL is positively correlated with GA of the conceptus (R² = 0.89, p < 0.05); however, CRL was not influenced by number of conceptus. Both the left and the right uterine horn gradually increased in size with the advancement of pregnancy irrespective of conceptus number present in the horn. The size of the amniotic sac of conceptus gradually increased with the conceptus age but maintained spherical shape from 5 to 7 weeks of pregnancy. The amniotic fluid formed by individual conceptus rapidly increased from 5 weeks (3.4 ± 0.3 mL) to 7 weeks (21.0 ± 2.0 mL) and 9 weeks (111.5 ± 4.0 mL). The volume of allantoic fluid formed by individual conceptus was steadily increased until 7 weeks (60.0 ± 5.0 mL) and began to decline slowly thereafter (50.0 ± 5.0 mL at 9 weeks). Notably, there was no effect of conceptus number per pregnancy on individual amniotic and allantoic fluid volume. The cotyledons have first appeared on the allanto-chorionic surface from 4 to 5 weeks of pregnancy. The closed eye, nostril and hooves of the conceptus became visible at 7 weeks of pregnancy. The present study has shown the basic information on conceptus-related developmental changes during early pregnancy up to 9 weeks in Black Bengal goat.