• Asian-Australasian Journal of Animal Sciences
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• v.33 no.8
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• pp.1360-1368
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• 2020

Objective: The aim of our study was to determine the associations of heifer reproductive performance with survival up to the first calving, first-lactation milk yield, and the probability of being culled within 50 days after first calving. Methods: Data from 33 large Holstein-Friesian commercial dairy herds were gathered from the official milk recording database in Hungary. The data of heifers first inseminated between January 1, 2011 and December 31, 2014 were analyzed retrospectively, using Cox proportional hazards models, competing risks models, multivariate linear and logistic mixed-effects models. Results: Heifers (n = 35,128) with younger age at conception were more likely to remain in the herd until calving, and each additional month in age at conception increased culling risk by 5.1%. Season of birth was related to first-lactation milk yield (MY1; n = 19,931), with cows born in autumn having the highest milk production (p<0.001). The highest MY1 was achieved by heifers that first calved between 22.00 and 25.99 months of age. Heifers that calved in autumn had the highest MY1, whereas calving in summer was related to the lowest milk production (p<0.001). The risk of culling within 50 days in milk in first lactation (n = 21,225) increased along with first calving age, e.g. heifers that first calved after 30 months of age were 5.52-times more likely to be culled compared to heifers that calved before 22 months of age (p<0.001). Calving difficulty was related to higher culling risk in early lactation (p<0.001). Heifers that required caesarean section were 24.01-times more likely to leave the herd within 50 days after first calving compared to heifers that needed no assistance (p<0.001). Conclusion: Reproductive performance of replacement heifers is closely linked to longevity and milk production in dairy herds.

• Toxicological Research
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• v.24 no.4
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• pp.245-251
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• 2008

Dietary restriction (DR) is the most efficacious intervention for retarding the deleterious effects of aging. DR increases longevity, decreases the occurrence and severity of age-related diseases, and retards the physiological decline associated with aging. The beneficial effects of DR have been mostly studied in non-neuronal tissues. However, several studies have showed that DR attenuate neuronal loss after several different insults including exposure to kainate, ischemia, and MPTP. Moreover, administration of the non-metabolizable glucose analog 2-deoxy-D-glucose (2DG) could mimic the neuroprotective effect of DR in rodent, presumably by limiting glucose availability at the cellular level. Based on the studies of chemically induced DR, it has been proposed that the mechanism whereby DR and 2DG protect neurons is largely mediated by stress response proteins such as HSP70 and GRP78 which are increased in neurons of rats and mice fed a DR regimen. In addition, DR, as mild metabolic stress, could lead to the increased activity in neuronal circuits and thus induce expression of neurotrophic factors. Interestingly, such increased neuronal activities also enhance neurogenesis in the brains of adult rodents. In this review, we focus on what is known regarding molecular mechanisms of the protective role of DR in neurodegenerative diseases and aging process. Also, we propose that DR is a mild cellular stress that stimulates production of neurotrophic factors, which are major regulators of neuronal survival, as well as neurogenesis in adult brain.

• Korea journal of population studies
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• v.26 no.1
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• pp.1-30
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• 2003

This paper attempts to explore the effects of ecological and socioeconomic factors on the level of mortality and the changing trends of such effects during the period of 1990∼2000. For this purpose the population census data and micro-data from the vital statistics for years 1990, 1995 and 2000 were used. As indicators of mortality, the crude death rate(CDR), the standardized death rate(SDR) and the longevity rate were calculated for 170 'Si' s and 'Gun's. Using GIS, this paper first presents the mortality and longevity maps for years 1990, 1995 and 2000. Then ANOVA and regression analyses are carried out in an effort to generalize the effects of ecological and socioeconomic factors on the CDR, the SDR and the longevity rate. When the mortality and longevity maps are examined, three indices of mortality are found to be markedly high in the southwest coastal regions of Cholla-Nam-Do. By contrast, Seoul and Pusan metropolitan areas show substantially low level of mortality and longevity in these indices. It is also found that the regional differentials in the SDR and the longevity rate show a trend of becoming smaller after 1990. The research, however, does not find any linear relationship between the SDR and the longevity rate. The causal mechanisms of the two indices are found to be different. The results of the ANOVA and the regression analysis reveal that the locational factors of both mountainous and farming regions tend to increase the CDR and SDR while both coastal and farming regions disclose a tendency of increasing the longevity rate. The level of statistical significance of these analytical results is found to be weaker when socioeconomic factors such as education, income, marital status, availability of medical care, and sanitary conditions of the region are taken into account. The regional differentials in the mortality level seem to have a clear relationship not only with the socioeconomic factors but also with the age structure influenced by the age selectivity of migration during the past 40 years.

• ALGAE
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• v.24 no.2
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• pp.93-104
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• 2009

Imaging-PAM fluorometry was used to assess the chlorophyll a fluorescence parameter ${\Phi}_{PSII}$ (effective quantum yield) in Frcus vesiculosus. F. disttchus. ssp. distichus and AscophyIIum nodosum. The objective was to show variadon in fluorescence yield associated with age and frond organ, and to illustrate the spatial scales at which photosynthetic parameters vary on fucoid thalli. In addition, our species represented taxa in different but related genera, species with different ecoloeies (rock pool and non rock pool species), morphologies (with and without air bladders) and longevities (several to 20 or more years). A further objective was to determine the extent to which photosynthetic parameters reflected these differences- Effective quantum yield declined substantially with age in F. vesiculosus and F. distichus ssp. distichus, whereas ${\Phi}_{PSII}$ in A. nodosum was maximal after three years. In A. nodosum ${\Phi}_{PSII}$ was still high in branch segments at least seven years old. Older branches of A. nodosum showed relatively higher and more homogeneous photosynthetic capacity relative to Fucus species. Surfaces of air bladders in A. nodosum and F. vesicu- losus had ${\Phi}_{PSII}$ that was not significantly different from the highest rates, achieved in these species. The heterogene- ity of photosynthetic efficiency is consistent with morphological and developmental differences among the species and their ecology. in particular the longevity of A. nodosum fronds.

• BMB Reports
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• v.46 no.4
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• pp.181-187
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• 2013

Caloric restriction is the most reliable intervention to prevent age-related disorders and extend lifespan. The reduction of calories by 10-30% compared to an ad libitum diet is known to extend the longevity of various species from yeast to rodents. The underlying mechanisms by which the benefits of caloric restriction occur have not yet been clearly defined. However, many studies are being conducted in an attempt to elucidate these mechanisms, and there are indications that the benefits of caloric restriction are related to alteration of the metabolic rate and the accumulation of reactive oxygen species. During molecular signaling, insulin/insulin-like growth factor signaling, target of rapamycin pathway, adenosine monophosphate activated protein kinase signaling, and Sirtuin are focused as underlying pathways that mediate the benefits of caloric restriction. Here, we will review the current status of caloric restriction.

• Communications for Statistical Applications and Methods
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• v.28 no.2
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• pp.171-188
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• 2021

Due to an increased demand for longevity risk analysis, various stochastic models have been suggested to evaluate uncertainly in estimated life expectancy and the associated value of future annuity payments. Recently updated data allow us to analyze mortality for a longer historical period and extended age ranges. This study followed up previous case studies using up-to-date empirical data on Korean mortality and the recently developed R package StMoMo for stochastic mortality models analysis. The suitability of stochastic mortality models, focusing on retirement ages, was investigated with goodness-of-fit, validity of models, and ability of generating reasonable sets of simulation paths of future mortality. Comparisons were made across various types of models. Based on the selected models, the variability of important estimated measures associated with pension, annuity, and reverse mortgage were quantified using simulations.

• BMB Reports
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• v.54 no.5
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• pp.253-259
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• 2021

Aging is characterized by a functional decline in most physiological processes, including alterations in cellular metabolism and defense mechanisms. Increasing evidence suggests that caloric restriction extends longevity and retards age-related diseases at least in part by reducing metabolic rate and oxidative stress in a variety of species, including yeast, worms, flies, and mice. Moreover, recent studies in invertebrates - worms and flies, highlight the intricate interrelation between reproductive longevity and somatic aging (known as disposable soma theory of aging), which appears to be conserved in vertebrates. This review is specifically focused on how the reproductive system modulates somatic aging and vice versa in genetic model systems. Since many signaling pathways governing the aging process are evolutionarily conserved, similar mechanisms may be involved in controlling soma and reproductive aging in vertebrates.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.45-49
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• 2006

The present investigation was conducted to know the effects of host age on development and morphological characteristics of Nesolynx thymus, a gregarious ectopupal parasitoid of the uzi fly, Exorista bombycis, a serious en do-larval parasitoid of the silkworm, Bombyx mori L. For experimentation, 3 - 11 day-old pupae of E. bombycis were exposed to 2 day-old adults of N. thymus at $25{\pm}2^{\circ}C\;and\;60{\pm}10%$ RH. A highly significant negative correlation between host age and the following development and morphological characteristics of the parasitoid was observed: number of pupae parasitised, total adult recovery, sex ratio and recovery, longevity, body length, wing span, abdomen length, and abdomen width of females. The findings of the present study clearly demonstrate that various development and morphological parameters of N. thymus are influenced by the age of E. bombycis pupae.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.4
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• pp.417-424
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• 2014

The purpose of this study was to analyze the psychobiological traits of each Sasang typology based on the Sasang Digestive function Inventory (SDFI) which measures the Sasang type-specific pathophysiological digestive symptom. The SDFI, Temperament and Character Inventory (TCI) and NEO-Personality Inventory (NEOPI) were measured with 199 College students. The correlation coefficient was measured with Pearson correlation among SDFI, TCI, and NEOPI. The influence of TCI, sex and age on SDFI and its subscales were analyzed with regression analysis. We also compared the psychobiological features between high and low SDFI score groups to elucidate its psychobiological profiles. There was significant correlation between SDFI and TCI Harm-Avoidance (r=-0.192, p<0.001). The SDFI subscales were showed to have significant correlations with subscales of NEOPI and TCI. The regression model with TCI can explain 8-16% of type-specific pathophysiological digestive symptoms. The low SDFI score group ($39{\pm}9.3$) has significantly (p=0.007) higher than the high SDFI group ($33.6{\pm}12.2$) in TCI Harm-Avoidance which is considered important for the gastrointestinal dysfunction and So-Eum type differentiation. We found that the TCI may explain the mechanism underneath the Sasang type-specific pathophysiological symptom. It was suggested that the TCI Reward-Dependence would be useful for the study on Tae-Eum Sasang type, and its clinical meanings were discussed in the pathophysiological perspectives.

• Journal of Veterinary Science
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• v.24 no.6
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• pp.81.1-81.12
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• 2023

Background: The incidence of colic and the outcomes of colic surgery have not been surveyed in racetracks in Korea. Objectives: This study examined the incidence, mortality, and case fatality of colic and investigated the effects of age and sex after an exploratory celiotomy on the long-term survival rate (return to racing), subsequent racing performance, and career longevity. Methods: The incidence, mortality, and case fatalities of colic were examined over an 11-year period. The records of 40 horses that had undergone a celiotomy, after participating in at least one race and 75 race-matched control horses were analyzed. The racing performance and career length of the horses that returned to racing post-surgery were compared with a control group. Results: The annual incidence, fatality rate of colic, and annual mortality rate at Seoul Racecourse were 6.5, 2.8 per 100 horse-years, and 0.2 deaths cases per 100 horse-years, respectively. Of the 40 horses that underwent colic surgery, 26 (65%) returned to racing. The likelihood of returning to racing decreased with increasing age of the horses, and geldings had a lower probability of returning. While the performance in the five preoperative races between the two groups was not significantly different, a significant decrease in racing performance was observed after the surgery date (p < 0.01). Horses that underwent colic surgery did not show a significant decrease in career length. Conclusions: Surgical treatment for colic at the age of three and four years had a negative impact on the racing performance. On the other hand, there was no significant difference in career longevity between the two groups.