• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.435-441
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• 2013

This retrospective study evaluated the effects of the interval from calving to first insemination (ICFI) and days open (DO) on the reproductive performance in dairy cows. In the first analysis, data from 705 cows were grouped based on the ICFI: short (30-60 days, n=217), medium (61-90 days, n=309), and long (91-150 days, n=179). The occurrence of endometritis was greater in the long group than in short and medium groups (p<0.05). The occurrence of ovarian cysts increased with increasing ICFI (p<0.05), while body condition score (BCS) during the 5 month postpartum period was lower with increasing ICFI (p<0.01). The hazard of pregnancy by 365 days in milk (DIM) was lower (hazard ratio [HR]=0.70, p<0.0001) in the long group, but higher (HR=1.41, p<0.0001) in the short group compared with the medium group. In the second analysis, data from 436 cows were grouped based on the DO: short (30-90 days, n=154), medium (91-180 days, n=183), and long (181-360 days, n=99). The occurrence of a retained placenta was greater in the long group than in the medium group (p < 0.05). Ovarian cysts occurred more frequently in medium and long groups than in the short group (p=0.08). BCS was lower in the short group compared with medium and long groups at month 1 postpartum (p<0.05). Milk yield (kg/day) was greater in the medium group compared with the short group at months 2 to 5 postpartum (p<0.05). The hazard of first insemination by 150 DIM was lower in the long group than in the short group (HR=0.73; p<0.02). The hazard of pregnancy by 365 DIM was lower (HR=0.64, p<0.0001) in the long group than in the medium group, while the hazard did not differ between short and medium groups (p>0.05). Moreover, the culling rate was greater in the long group than in the short group (p<0.05). In conclusion, a longer ICFI and DO resulted in reduced reproductive performance in dairy cows, which was attributable to an increase in postpartum diseases, a lower BCS and a greater milk yield.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.64-70
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• 2009

The aims of this study is to examine the effects of the changes in HRT(Hydraulic Retention Time) and media charge in a water-mill, among other operation factors, on the nitrogen and phosphorus removal in order to use up-flow anaerobic reactors, anoxic reactors and water-mill aerobic reactors for sewage treatment. The extension of HRT improved the nitrogen removal efficiency, however the removal pattern was constant regardless of HRT. The removal of phosphorus was constant (80%-90%) regardless of the change in HRT. The removal rate with change in influx load varied such that at the OLR (Organic Load Rate) of 1-3 kg/d, the T-N removal efficiency was 80.7%-88.9% and the T-P removal efficiency was 82.9%-89.3% while at the NLR (Nitrogen Loading Rate) of 0.108-0.156 kg/d the removal efficiencies were 80.7-88.9% (T-N) and 82.9-89.3% (T-P). The analyses of the nitrogen and phosphorous removal characteristics with the C/N and C/P ratio showed that the mean T-N removal rate was 88% at the C/N ratio of 1.2-2.6, and that the mean T-P removal rate was 86% at the C/P ratio of 7.2-14.1. Also, the analysis of nitrogen and phosphorous removal characteristics were analyzed in relation to media charge. The comparison between with and without media charge in the water-mill showed that while the nitrogen removal efficiencies were 86-94% and 85-89% respectively, the difference of phosphorous removal efficiencies were between the two conditions was not significant, thus it suggested that the media charge has less effect on the removal efficiency of phosphorous compared to that of nitrogen.

• Journal of the Korean Magnetics Society
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• v.6 no.3
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• pp.151-157
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• 1996

Magnetic properties and microstructures of FeTaNC thin films, which were deposited by magnetron reactive sputtering rrethod, were investigated as a function of $CH_{4}$ and $N_{2}$ gas partial pressures. Magnetic properties of FeTaNC films depended on total reactive gas pressure as well as $CH_{4}/N_{2}$ pressure ratios. For reactive gas partial pressures of 5~10 %, optimum magnetic properties were observed in the FeTaNC films with proper $CH_{4}/N_{2}$ ratio. On the other hand, at 15% of gas partial pressure, FeTaN and FeTaC films showed superior properties to FeTaNC films. Above 15%, the magnetic properties of films rapidly degraded due to an excess incorporation of C and/or N atoms. Excellent soft magnetic properties of 17 kG of Bs, 0.3 Oe of He, and 4000 of $\mu'$(at 5 MHz) were obtained in the FeTaNC films. High permeabilities of FeTaNC films could be explained by the Fe lattice distortion caused by N atoms, hence reduction of magnetic anisotopy. While precipitated TaN and TaC particles effectively supress the growth of $\alpha-Fe$ grains leading to a good soft magentic properties, FeN and FeC phases such as $Fe_3N$, $Fe_4N$, FexC have detrimental effects.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.2
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• pp.94-102
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• 2014

This study was conducted to estimate and compare the effects of bacterial inoculants and organic acids on silage quality. Silage pH, lactate, acetate, lactate:acetate ratio, propionate, butyrate, water-soluble carbohydrate, crude protein, ammonia-N, neutral detergent fiber and acid detergent fiber (ADF) were used as parameters for quality analysis and a meta-analysis technique was employed to determine the effect size. As a data pool for analysis, we examined 14 research papers. Bacterial inoculants were found to elevate pH, lactate, acetate, lactate:acetate ratio, propionate and ADF contents compared to the controls (p<0.01). In contrast bacterial inoclulants decreased butyrate, water-soluble carbohydrate, crude protein and ammonia-N contents (p<0.01). In the organic acid treatments, all parameters except ADF showed higher contents than the control (p<0.01). In the comparison of effect sizes between the two treatments, significant differences were detected in butyrate, water-soluble carbohydrate, crude protein and ammonia-N (p<0.05). It may be concluded that bacterial inoculants could improve silage quality in terms of the aforementioned four parameters compared with organic acid treatments.

• Journal of Gastric Cancer
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• v.16 no.4
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• pp.207-214
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• 2016

Purpose: The utility of N classification has been questioned after the 7th edition of the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) was published. We evaluated the correlation between ratio-based N (rN) classification with the overall survival of pathological T4 gastric cancer patients who underwent D2 lymphadenectomy. Materials and Methods: We reviewed 222 cases of advanced gastric cancer patients who underwent curative gastrectomy between January 2006 and December 2015. The T4 gastric cancer patents were classified into four groups according to the lymph node ratio (the number of metastatic lymph nodes divided by the retrieved lymph nodes): rN0, 0%; rN1, ${\leq}13.3%$; rN2, ${\leq}40.0%$; and rN3, >40.0%. Results: The rN stage showed a large down stage migration compared with pathological T4N3 (AJCC/UICC). There was a significant difference in overall survival between rN2 and rN3 groups in patients with pT4N3 (P=0.013). In contrast, the difference in metastatic lymph nodes was not significant in these patients (${\geq}16$ vs. <15; P=0.177). In addition, the rN staging system showed a more distinct difference in overall survival than the pN staging system for pathological T4 gastric cancer patients. Conclusions: Our results confirm that rN staging could be a good alternative for pathological T4 gastric cancer patients who undergo D2 lymphadenectomy. However, before applying this system to gastric cancer patients who undergo D2 lymphadenectomy, a larger sample size is required to further evaluate the usefulness of the rN staging system for all stages, including less advanced stages.

• Journal of Plant Biology
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• v.13 no.2
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• pp.21-31
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• 1970

The rice variety, Nongkwang was used in two factorial experiments with the combination of 15 kg and 20 kg of N per 10 a, 3 levels of P2O5 (0, 4 and 8 kg per 10 a) and 4 levels of potash(0, 2, 4 and 8 kg per 10 a) in the reclaimed soil areas containing 0.48% on the average salt content throughout the year(0.67% at the end of April). The absorption of N, K and Ca was accelerated by increased N applications. The absorption of P itself was not enhanced by the increased application of P2O5 but the absorption of K2O reduced the absorption of Mg was affected. The increased application of K2O reduced the absorption of Si and seemed to increase the content of carbohydrate in the rice plants. Twenty kg of N and 4kg of P2O5 per 10 a produced satisfactory yields of rough rice, potash applications are ineffective in this experiment on rice grain production.

• Journal of Korean Society of Forest Science
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• v.113 no.1
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• pp.66-72
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• 2024

Determining the nutrient stoichiometry in plant organs is critical for understanding nutrient uptake and cycling in forest ecosystems. This study evaluated nutrient concentrations and stoichiometry in various plant organs (stem, bark, branches, and foliage) of species found in four warm-temperate forests in southern Korea. Cryptomeria japonica D. Don (CJ), Quercus serrata Thunb. (QS), evergreen broadleaved tree species (EB), and bamboo spp. (BB) were destructively sampled to measure nutrient (C, N, and P) concentrations in the plant organs. The mean C concentration in the stem was significantly higher in CJ than in QS, BB, or EB, whereas the C concentration in the foliage was the lowest in BB. The mean foliar N and P concentrations were higher in BB than in EB or CJ. The mean stem C:N and C:P ratios were highest in CJ but were lowest in the foliage of BB. Overall, stems of all species showed a strong positive correlation between C concentration and dry weight, but a negative correlation between N and dry weight. The N and P concentrations of foliage and bark were strongly correlated, whereas those of the stem and branches were poorly correlated. Positive correlations were detected between the C:N and C:P ratios in bark and foliage. These results indicate the existence of intraspecific differences in nutrient requirements in warm-temperate forest species and add to the understanding of nutrient uptake and storage patterns in the organs of species growing in warm-temperate forests.

• Journal of Aquaculture
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• v.10 no.3
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• pp.335-346
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• 1997

Denitrification is one of the important processes of removing nitrate from in recirculating aquaculture systems. And this process is affected by many factors such as external organic carbon sources, hydraulic retention time (HRT), COD/NO3--N (C:N) ratio, etc. However, not many studies were done for the optimum conditions of denitrification in the recirculation system for aquaculture. Therefore, this study was conducted to find out the optimum removal condition of NO3--N using submerged denitrification biofilter. The combinations of two external organic carbon sources (glucose and methanol), two HRT (4 and 8-hour) and four differnent C : N ratios (3, 4, 5, 6) were tested. The removal efficiencies of NO3--N and total inorganic nitrogen (TIM) at 8-hour HRT were better than those at 4-hour's (P<0.05). The maximum removal efficiency of NO3--N by methanol (97.8%) was achieved at HRT and C : N ratio were 8-hour and 4.0 respectively. The efficiencies of methanol for the removal of NO3--N and TIN were always better than those of glucose (P<0.05). The maximum removal efficiencies of total inorgainc nitrogen (TIN) were gained at C : N ration of 5.0. The maximum removel efficiencies of TIN using methanol and glucose were 96.9% and 71.5% respectively. Anaerobic condition which is necessary for denitrification process was not made until the 8-hour HRT and higher C : N ratio (5.0). Removal of NO3--N at 4-hour HRT and C : N ration lower than 5.0 were inhibited by oxygen and/or low quantity of external organic carbon. Removal efficiencies of NO3--N were also inhibited by high C : N (6.0) ratio when HRT was 8-hour.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.41-48
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• 2008

Fermentative $H_2$ production was studied using microbial consortia isolated from heat-treated ($90{\circ}C$, 20 min) sewage sludge. Important parameters investigated were carbon(C) and nitrogen(N)-sources, C/N ratio, phosphate concentration, pH and temperature during anaerobic cultivation in serum bottles. Starch, ribose, sucrose and glucose were good C-sources for the culture growth and $H_2$ production. Yeast extract was better N-source than $(NH_4)_2SO_4$ or peptone when individually added to the synthetic media, however the combination of above three N-sources exhibited the additional effect for cell growth and $H_2$ evolution. Addition of 100 mM phosphate as a buffering agent prevented the rapid pH drop during the cultivation. The optimum initial pH for the cell growth was at 7.0, whereas $H_2$ production was observed at pH 5.5. Optimum temperature for the cell growth and $H_2$ production was $37{\circ}C$. Initial C/N ratio of 1.22 in the media using glucose and yeast extract as the C- and N-sources, respectively, showed the $H_2$ yield 1.0 mol $H_2$/mol glucose.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.62-65
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• 1995

CdTe crystals were grown by the vertical Bridgman method. P-type DcTe crystals were grown with Cd:Te= 1:1.001 wt. % ratio, while n-type CdTe crystals were 1:1 Also, CdTe:In crystals were investigated, Lattic constants were 6.489${\AA}$ for p-type 6.480${\AA}$for n=type and 6.483${\AA}$ for CdTe:In EPD was 10$\^$-3/-10$\^$4/cm$\^$-2/ for n-, p-type CdTd, 10$\^$4/-10$\^$5/cm$\^$-2 for Cd:Te:In using by E-Ag solution for (111) plane The carrier concentration, the resistivity and the Hall carrier mobility measured by the van der Pauw method were p=5.78${\times}$10$\^$15/cm$\^$-3/, $\rho$=20.2$\Omega$cm, ${\mu}$$\sub$p/=75.6cm$\^$-2/ V$\^$-1/ sec$\^$-1/ for p-typem n=2.98${\times}$10$\^$16/cm$\^$-3/, $\rho$=0.214$\Omega$cm, ${\mu}$$\sub$p/=978.9cm$\^$-2/ V$\^$-1/ sec$\^$-1/ for n-type and n=7.45${\times}$10$\^$16/cm$\^$-3/, $\rho$=1.54 ${\times}$10$\^$3/$\Omega$cm, ${\mu}$$\sub$p/=658.4 cm$\^$-2/ V$\^$-1/ sec$\^$-1/ for CdTe:In crystals, Transmittance of p-type CdTe was 61% that of n-type was 65%, Cd:Te:In showed 60% IR transmittance.