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Constraining primordial non-Gaussianity with the 3-point correlation function of the SDSS-IV eBOSS DR14 quasar sample

  • Choi, Peter D.;Rossi, Graziano;Slepian, Zachary;Eisenstein, Daniel;Ho, Shirley;Schlegel, David
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.53.3-53.3
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    • 2017
  • While quasars are sparse in number density, they reside at relatively high-redshift as compared to galaxies. Hence, they are likely to be less non-linearly evolved than the galaxy population, and thus have a distribution that more closely mirrors the primordial density field. Therefore, they offer an intriguing opportunity to search for primordial non-Gaussianity (PNG). To this end, the 3-point correlation function (3PCF) is an excellent statistical tool to detect departures from Gaussianity, vanishing for a Gaussian field. In this work, we will make the first-ever measurement of the large-scale quasar 3PCF from the SDSS-IV DR14 quasar sample (spanning the largest volume to-date) to place constraints on PNG through the usual f_NL-type parametrization. This work will use the order N^2-time 3PCF algorithm of Slepian & Eisenstein (2015), with N the number of objects.

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Modified Multi-Level Skip-Lot Sampling Plans

  • Cho, Gyo-Young;Choi, Eun-Jung
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.4
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    • pp.915-927
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    • 2003
  • This paper is the generalization of the modified two-level skip-lot sampling plan(MTSkSP1) to n-level. The general formulas of the operating characteristic(OC) function, average sample number(ASN) and average outgoing quality(AOQ) for the plan are derived using Markov chain properties. The operating characteristic curves, average sample numbers and average outgoing qualities of a reference plan, modified two-level, three-level and five-level skip-lot sampling plans are compared.

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Quality of Freeze-Dried Yulmoo-kimchi (동결건조 열무김치의 품질)

  • Ko, Young-Tae;Kang, Jung-Hwa
    • Korean Journal of Food Science and Technology
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    • v.35 no.2
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    • pp.254-259
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    • 2003
  • Effects of freeze-drying on microbiological and sensory characteristics of yulmoo-kimchi (leaf radish kimchi) were investigated. Freeze-dried yulmoo-kimchi was stored at 0, 10 or $25^{\circ}C$ for 60 days and rehydrated with water. Optimum rehydration time of freeze-dried yulmoo-kimchi was 2 hr. Number of lactic acid bacteria of freeze-dried, 10 days-stored, rehydrated yulmoo-kimchi decreased significantly (p<0.05) in comparison with that of reference sample (non-freeze-dried yulmoo-kimchi), while no significant changes were observed after 10 days. As storage temperature increased, number of lactic acid bacteria of 10 days-stored samples decreased. pH value slightly increased by freeze-drying, while it decreased gradually during 60 days of storage. Sensory properties of freeze-dried/rehydrated sample were slightly inferior to those of reference sample, but those were relatively good when the sample was evaluated solely. Overall acceptability of freeze-dried, $0^{\circ}C$-stored, rehydrated sample was significantly inferior to reference sample (p<0.05) and it gradually decreased as storage temperature increased. Between storage periods of 10 through 60 days, sensory properties of 0 and $10^{\circ}C$-stored sample slightly decreased, while those of $25^{\circ}C$-stored sample decreased markedly.

The Effects of Sugar Addition in Yogurt Prepared from Egg White Powder and Casein (난백분말과 카제인으로 만든 요구르트에서 당의 첨가 효과)

  • 고영태;이주원
    • Korean journal of food and cookery science
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    • v.12 no.2
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    • pp.153-161
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    • 1996
  • A curd yogurt was prepared from egg white powder (EWP) and casein added with sugars (glucose, fructose, lactose). The effects of sugar addition on acid production and growth of Lactobacillus were studied. The effects of sugar addition on sensory property and volatile aroma compounds were also studied. Acid production by L. acidophilus in EWP 2% (W/V), casein 3% (w/v) and sugar 0.5,1 or 2% W/V) was lower than that of L. acidophilus in milk (control). Acid production in sample added with glucose or fructose of 1% or 2% (W/V) was higher than that of 0.5% (W/V), while acid production in lactose added sample was not affected with the concentration of lactose. Number of viable cells of L. acidophilus at 24 hr in milk, glucose added sample, fructose added sample and lactose added sample was 3.6${\times}$10/Sup 9/, 5.6${\times}$10$\^$8/, 6.0${\times}$10$\^$8/,and 3.2${\times}$10$\^$7/, respectively. Through 30hr fermentation, acid production and number of viable cells of L. acidophilus in milk were higher than those of sugar added samples. Sensory property of fructose added sample was slightly better than that of milk yogurt (reference), while that of lactose added sample was significantly inferior. Though the composition of volatile aroma compounds was slightly different according to sample, gas chromatographic analysis detected acetone, ethanol, diacetyl and acetoin in samples fermented by L. acidophilus.

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Effects of Samchulkunbitang on the Immunosuppression Induced by Methotrexate in Rats (삼출건비탕(蔘朮健脾湯)이 흰쥐의 면역반응(免疫反應)에 미치는 영향(影響))

  • Lee Seung-Yeon;Kim Jang-Hyun
    • The Journal of Pediatrics of Korean Medicine
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    • v.12 no.1
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    • pp.257-276
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    • 1998
  • Introduction The effects of Samchulkunbitang on the immunosuppression induced by methotrexate in rats were investigated in this experument. The multiple parameters of immunity assessed in each rats includes the rate of body weight loss, weight changes in thymus, spleen and axillary lymphnode. The number of lymphocytes and CD4+ T cell count in the blood, thymus, spleen and axillary lymphnode were also measured. Methodology Male Sprague-Dawley rats were chosen as an experiment object and were divided into 4 groups by a random selection. Each group consisted of 6 rats. The normal group didn't receive any treatment. The control group was administered with methotrexate for 5 days. The sample Ⅰ group was administered with Samchulkunbitang for 5 days. The sample Ⅱ group was administered with both Samchulkunbitang and methotrexate for 5 days. The dosage of medication was 2cc/day, 1cc given at 10 AM and another 1cc given at 5 PM. Results The rate of body weight loss was significantly increased in the Sample Ⅰ and Sample Ⅱ group. The weight of thymus and spleen were significantly increased in Sample Ⅰ and Sample Ⅱ groups While the weight of axillary lymphnode did not show much increase. No significant differences were measured among the experimental groups. Blood lymphocyte count, blood CD4+ T cell count, spleen lymphocyte count, axillary lymphnode lymphocyte and CD4+ T cell count were significantly increased in Sample Ⅰ and Sample Ⅱ groups while spleen CD4+ T cell count did not show much increase. No significant differences were measured among the experimental groups. Conclusion As one can witness from the above results, administration of Samchulkunbitang played potent role in increasing immune system among the rats treated with methotrexate which induces immunosuppression. Overall increase of lymphocyte count and CD4+ T cell count in the sample groups with Samchulkunbitang effectively proves its ability to boost the immune system.

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Validation of Suitable Zooplankton Enumeration Method for Species Diversity Study Using Rarefaction Curve and Extrapolation (종 다양성 평가를 위한 호소 생태계 동물플랑크톤 조사 방법 연구: 희박화 분석(rarefaction analysis)을 이용한 적정 시료 농축 정도 및 부차 시료 추출량의 검증)

  • Hye-Ji Oh;Yerim Choi;Hyunjoon Kim;Geun-Hyeok Hong;Young-Seuk Park;Yong-Jae Kim;Kwang-Hyeon Chang
    • Korean Journal of Ecology and Environment
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    • v.55 no.4
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    • pp.274-284
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    • 2022
  • Through sample-size-based rarefaction analyses, we tried to suggest the appropriate degree of sample concentration and sub-sample extraction, as a way to estimate more accurate zooplankton species diversity when assessing biodiversity. When we collected zooplankton from three reservoirs with different environmental characteristics, the estimated species richness (S) and Shannon's H' values showed different changing patterns according to the amount of sub-sample extracted from the whole sample by reservoir. However, consequently, their zooplankton diversity indices were estimated the highest values when analyzed by extracting the largest amount of sub-sample. As a result of rarefaction analysis about sample coverage, in the case of deep eutrophic reservoir (Juam) with high zooplankton species and individual numbers, it was analyzed that 99.8% of the whole samples were represented by only 1 mL of sub-sample based on 100 mL of concentrated samples. On the other hand, in Soyang reservoir, which showed very small species and individual numbers, a relatively low representation at 97% when 10 mL of sub-sample was extracted from the same amount of concentrated sample. As such, the representation of sub-sample for the whole zooplankton sample varies depending on the individual density in the sample collected from the field. If the degree of concentration of samples and the amount of sub-sample extraction are adjusted according to the collected individual density, it is believed that errors that occur when comparing the number of species and diversity indices among different water bodies can be minimized.

Reduction in Sample Size for Efficient Monte Carlo Localization (효율적인 몬테카를로 위치추정을 위한 샘플 수의 감소)

  • Yang Ju-Ho;Song Jae-Bok
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.5
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    • pp.450-456
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    • 2006
  • Monte Carlo localization is known to be one of the most reliable methods for pose estimation of a mobile robot. Although MCL is capable of estimating the robot pose even for a completely unknown initial pose in the known environment, it takes considerable time to give an initial pose estimate because the number of random samples is usually very large especially for a large-scale environment. For practical implementation of MCL, therefore, a reduction in sample size is desirable. This paper presents a novel approach to reducing the number of samples used in the particle filter for efficient implementation of MCL. To this end, the topological information generated through the thinning technique, which is commonly used in image processing, is employed. The global topological map is first created from the given grid map for the environment. The robot then scans the local environment using a laser rangefinder and generates a local topological map. The robot then navigates only on this local topological edge, which is likely to be similar to the one obtained off-line from the given grid map. Random samples are drawn near the topological edge instead of being taken with uniform distribution all over the environment, since the robot traverses along the edge. Experimental results using the proposed method show that the number of samples can be reduced considerably, and the time required for robot pose estimation can also be substantially decreased without adverse effects on the performance of MCL.

Galaxy overdensities at intermediate to high redshift

  • Kang, Eu-Gene;Im, Myung-Shin
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.52.2-52.2
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    • 2011
  • We searched and studied galaxy overdensities at 0.6 < z < 4.5 in the areas of two GOODS fields. These overdensities are identified by running top-hat filters on the two dimensional spatial distribution of two galaxy samples - a K-band limited, photometric redshift sample at 0.6 < z < 4.5, and BVz-color selected sample targeting overdensities at z ~ 3.7 and z ~ 4.0. Here photometric redshifts are derived from multi-wavelength data ranging from U-band through 8 micron band of the Spitzer. We find 52 overdensities with significances of 3.5-7 ${\sigma}$. The derived masses found to be a > $10^{13}\;M_{\odot}$ with the comoving number density of a few ${\times}10^{-6}\;Mpc^{-3}$ at z ~ 3. In order to understand the high number density of massive overdensities at high redshift, we carried out an analysis of galaxy overdensities using the mock galaxy catalog based on Millennium simulation selected in the same way as the analysis of the observational data. In the simulation, we find 650 galaxy overdensities with a 3.5 ${\sigma}$ detection threshold over $2^{{\circ}2}$ sky field. The number density of the very massive overdensities (M > $10^{14}\;M_{\odot}$) in simulation shows a similar trend with the observation. We further discuss implications of our results.

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A Study on Financial Management Practices of Rural Housewives (농촌 주부의 재무관리 행동에 관한 연구 -도시근교 농촌을 대상으로-)

  • 배희선;최은숙
    • Korean Journal of Rural Living Science
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    • v.6 no.2
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    • pp.137-149
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    • 1995
  • The first objective of this study is to examine the finanacial management practices of rural housewives. The second objective is to determine the effects of sociodemographic characteristics on financial management practices. The Deacon & Firebaugh's model of family resource management framework and previous studies were used to determine the effects, regarding a9e, income, number of family, education level, and farming/nonfarming as independent/input variables, and monthly saving and managerial behavior index as dependent/throughput variables. A sample of 179 rural housewives aged less than 60 was selected from Shihung-Si Gyonggi-Do Province. Results showed that rural housewives more frequently did keeping bills, making purchase-list and verifying purchase need than recording where money spent making financial plan, and evaluating spending. With regard to household debt use, 60% of the sample had debt the most borrower used debt for farming, 73% of borrowers paid for their debt behind the schedule, and the main source of borrowing was NACF (NongHyup). Using installment credit, the rural housewives mainly bought cosmetics. 25% of the sample had credit cards. Average debt was 6, 070, 000 won, and 81% of annual income. In terms of saving, 85% of the sample saved, and 23% of the sample lived with the money after save. The main reasons of saving were for education and marriage of children and emergency. The main saving institutions were NACF and NLCF (ChukHyup). The regression showed that income was negatively associated with monthly saving, and age was identified as the positive determinants of managerial behavior index.

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