• Title/Summary/Keyword: radio sources

Search Result 284, Processing Time 0.051 seconds

Simultaneous 22GHz Water and 44GHz Methanol Maser Survey of Ultra-compact HII Regions

  • Kim, Won-Ju;Kim, Kee-Tae;Kim, Kwang-Tae
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.37 no.1
    • /
    • pp.83.2-83.2
    • /
    • 2012
  • We have carried out simultaneous 22GHz $H_2O$ and 44GHz Class I $CH_3OH$ maser survey of 112 ultra-compact HII regions (UCHIIs) twice in 2010 and 2011. We detected $H_2O$ maser and $CH_3OH$ maser emission from 76(68%) and 49(44%) UCHIIs, respectively. Among them 15 $H_2O$ masers and 32 $CH_3OH$ masers are new detections. These high detection rates suggest that the occurrence periods of both masers are significantly overlapped with the UCHII phase. $CH_3OH$ masers always have small (<10 km s-1) relative velocities with respect to the natal molecular cores, while $H_2O$ masers often show larger velocities. We find 20 UCHIIs with $H_2O$ maser lines at relative velocities >30 km s-1. The formation and disappearance of $H_2O$ masers is frequent over one-year time interval. In contrast, $CH_3OH$ masers usually do not show substantial variation in intensity, velocity, or shape. The isotropic luminosities of both masers well correlate with the bolometric luminosities of the central stars when data points of lowand intermediate-mass protostars are added: $L_{H_2O}=5.89{\times}10^{-9}{(L_{bol})^{0.69}}$ and $L_{CH_3OH}=4.27{\times}10^{-9}{(L_{bol})^{0.62}}$. They also tend to increase with the 2cm radio continuum luminosity of UCHIIs and the 850 um continuum luminosity of the associated molecular cores. We discuss some individual sources.

  • PDF

LOCAL ANOMALIES AROUND THE THIRD PEAK IN THE CMB ANGULAR POWER SPECTRUM OF WMAP 7-YEAR DATA

  • Ko, Kyeong Yeon;Park, Chan-Gyung;Hwang, Jai-Chan
    • Journal of The Korean Astronomical Society
    • /
    • v.46 no.2
    • /
    • pp.75-91
    • /
    • 2013
  • We estimate the power spectra of the cosmic microwave background radiation (CMB) temperature anisotropy in localized regions of the sky using the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year data. We find that the north and south hat regions at high Galactic latitude ($|b|{\geq}30^{\circ}C$) show an anomaly in the power spectrum amplitude around the third peak, which is statistically significant up to 3. We try to explain the cause of the observed anomaly by analyzing the low Galactic latitude ($|b|$ < $30^{\circ}C$) regions where the galaxy contamination is expected to be stronger, and the regions weakly or strongly dominated byWMAP instrument noise. We also consider the possible effect of unresolved radio point sources. We find another but less statistically significant anomaly in the low Galactic latitude north and south regions whose behavior is opposite to the one at high latitude. Our analysis shows that the observed north-south anomaly at high latitude becomes weaker on regions with high number of observations (weak instrument noise), suggesting that the anomaly is significant at sky regions that are dominated by the WMAP instrument noise. We have checked that the observed north-south anomaly has weak dependences on the bin-width used in the power spectrum estimation, and on the Galactic latitude cut. We also discuss the possibility that the detected anomaly may hinge on the particular choice of the multipole bin around the third peak. We anticipate that the issue of whether or not the anomaly is intrinsic one or due to WMAP instrument noise will be resolved by the forthcoming Planck data.

Informational Needs of Women with Breast Cancer Treated with Chemotherapy

  • Abi Nader, Elie;Kourie, Hampig Raphael;Ghosn, Marwan;El Karak, Fadi;Kattan, Joseph;Chahine, Georges;Nasr, Fadi
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.17 no.4
    • /
    • pp.1797-1800
    • /
    • 2016
  • Background: Research in the field of informational needs of breast cancer patients is scarce. In the few published articles, these needs were usually not satisfied. The main objective of this study was to evaluate satisfaction regarding informational needs in women with breast cancer. The long-term goal was to guide physician-patient communication to meet these needs. Materials and Methods: A survey with 21 questions was completed by 84 female patients receiving chemotherapy in a one-day hospital in Beirut, Lebanon. All patients were aware of their disease and agreed to participate in the survey. Results: The doctor was the major source of information for patients followed by media (radio and television). The level of knowledge of patients concerning their disease was proportional to the number of information sources. Women aged younger than 45 years, diagnosed during the last three months before the survey and certified from high school were less satisfied with information given by the oncologist. The missing information was in relation with the steps of the treatment after the chemotherapy regimen, the risk of a family member (sisters and daughters) of developing the disease and management of lymphedema. Conclusions: This study generated a scale for the degree of satisfaction of information received by women with breast cancer from their oncologist. The physician can use this scale to improve his or her skills of communication to patients and diminish their level of fear and anxiety.

Monitoring of Genetically Modified Bean Sprouts at Traditional Markets in Seoul and a Survey of Perception of Traditional Market Merchants and High School Students on Genetically Modified Organisms (서울 일부지역 재래시장의 유전자재조합 콩나물의 판매실태 및 상인과 일부 고등학생의 유전자재조합 식품에 대한 인식도 조사)

  • Choi, Seul-Ki;Lim, Jung-Hoon;Shin, Jee-Seong;Jeong, Jin-An;Joung, Hyo-Jee
    • Korean Journal of Community Nutrition
    • /
    • v.15 no.5
    • /
    • pp.679-686
    • /
    • 2010
  • The purpose of this study is to monitor genetically modified bean sprouts at traditional markets in Seoul and to investigate perception of traditional market merchants and high school students on genetically modified organisms (GMOs). We analyzed 30 bean sprouts that were selected at 11 traditional markets in Seoul using the method of polymerase chain reaction (PCR). Also, we compared perception of GMOs between merchants (n = 30) and students (n = 126). Knowledge test about GMOs was performed by students. The result of PCR, 16.7% of bean sprouts were confirmed as GM bean sprouts (n = 5). Students had significantly more exposure to information about GMOs than merchants (p < 0.05). Major information sources about GMOs were from mass media (television, newspaper and radio). About half of subjects were not aware that they eat GMOs and GMOs are sold to consumers. Only 17.3% of subjects had constant eating intent for GMOs after perceiving foods that he/she usually eats are GMOs. 51.3% of subjects had willingness to purchase GMOs if GMOs have same quality and lower cost than natural foods. 37.2% of subjects thought that GMOs would be harmful to humans. Students had more positive perception of GMOs' side effects than merchants (p < 0.01). There was no merchant who knew labeling of GMOs. 19.1% of students knew labeling of GMOs. Students' mean percentage of correct answers of six questions about GMOs was 45.2%. Therefore, providing adequate information about GMOs is needed for consumer's choice whether to purchase GMOs or not.

Prospective Elementary Teachers' Perception on Food Risk in Seoul (식품 위해에 관한 서울지역 예비 초등교사들의 인식 수준 조사)

  • Jin, Dae-Il;Kim, Jeong-Weon
    • Korean journal of food and cookery science
    • /
    • v.25 no.6
    • /
    • pp.643-649
    • /
    • 2009
  • The purpose of this study was to assess the prospective teachers' perception of food risk with the goal of providing the ways to improve their knowledge and perception of food risk. A self-administered questionnaire was developed and offered to 307 freshman and sophomore in an elementary teacher-cultivating university located in Seoul. The collected data were analyzed in terms of frequencies, cross tabulation analysis, t-test and ANONA with a deviation level of 5% using SPSS 15.0. The results of this research were as follows: 'Taste' was identified as an important factor for purchasing food (54.4%), and 'Manufacture date/expiration date' (67.0%) was checked first before food was purchased. The respondants viewed food additives (66.8%) followed by environmental contaminants (17.6%) as the most dangerous factors for food consumption. Even though they did not know the actual level of risk these factors posed to food, they still perceived them as dangerous. Most of them did not have any educational experiences on food risk, and if any, their sources of information were TV (46.6%) and the internet (19.5%). And, they did want to have information on food risk through TV, radio (41.1%) and the internet(16.4%). Based on the above results, the subjects who have great potential to influence children appeared not to have sound knowledge or a balanced perception of food risks. Therefore, systematic educational opportunities for prospective teachers should be provided to promote food risk communication.

A Preliminary Study on Nutrition Education for Mothers: I. Nutrition Knowledge and Food Behavior of Mothers (주부들의 영양교육을 위한 사전 연구 I. 주부들의 영양지식과 식습관에 관한 조사 연구 -울산지역을 중심으로-)

  • 김혜경
    • Journal of the Korean Home Economics Association
    • /
    • v.25 no.2
    • /
    • pp.55-68
    • /
    • 1987
  • This study was conducted to assess the knowledge and attitudes toward nutrition and behavior of mothers by using 30-item nutrition knowledge test and questionnaire. Results were summarized as follows; 1. Nutrition knowledge 1) The average score of nutrition knowledge and perceived knowledge were respectively 18.0, 26.0(the highest marks 30) and the accuracy of the knowledge was 68.4%. Knowledge about energy and nutrients scored lower marks than food composition and disease. 2) Nutrition knowledge had significant correlation with age, education level and total income. With increasing education level, total income and decreasing age, nutrition knowledge score were getting higher. 2. Attitudes about nutrition 1) Most important sources of nutrition information were by order of radio, T.V., newspapers, megazines and neighbors. 2) 56.2 percent of mothers said that they do meal planning and the greatest mian concern which had influence on meal planning was their hauband.(62.1%) 3) Among the mothers who responded 43.8 percent reported that they bring shopping list with them. 4) 72.6 percent of them wanted to participate re-education. 3. Food behavior 1) Most of mothers(93.1%) used instant food, regarding the reason for using instant food, 67.3 percent of them responded that is is convinient for cooking and 27.8 percent responded that it is for their familys' perference. 2) Mothers who had higher education level, tend to regard nutrition as the most important thing to cook, and with lower education level, they care more about taste. 3) Supper was the most main meal among three males of day.(75.9%) 4) 53.4 percent of mothers said they eat bread as a meal. This study provided baseline data for planning nutrition education programming for mothers.

  • PDF

2D GENUS TOPOLOGY OF 21-CM DIFFERENTIAL BRIGHTNESS TEMPERATURE DURING COSMIC REIONIZATION

  • Hong, Sungwook E.;Ahn, Kyungjin;Park, Changbom;Kim, Juhan;Iliev, Ilian T.;Mellema, Garrelt
    • Journal of The Korean Astronomical Society
    • /
    • v.47 no.2
    • /
    • pp.49-67
    • /
    • 2014
  • A novel method to characterize the topology of the early-universe intergalactic medium during the epoch of cosmic reionization is presented. The 21-cm radiation background from high redshift is analyzed through calculation of the 2-dimensional (2D) genus. The radiative transfer of hydrogen- ionizing photons and ionization-rate equations are calculated in a suite of numerical simulations under various input parameters. The 2D genus is calculated from the mock 21-cm images of high-redshift universe. We construct the 2D genus curve by varying the threshold differential brightness temperature, and compare this to the 2D genus curve of the underlying density field. We find that (1) the 2D genus curve reflects the evolutionary track of cosmic reionization and (2) the 2D genus curve can discriminate between certain reionization scenarios and thus indirectly probe the properties of radiation-sources. Choosing the right beam shape of a radio antenna is found crucial for this analysis. Square Kilometre Array (SKA) is found to be a suitable apparatus for this analysis in terms of sensitivity, even though some deterioration of the data for this purpose is unavoidable under the planned size of the antenna core.

A Survey on RF Energy Harvesting System with High Efficiency RF-DC Converters

  • Khan, Danial;Basim, Muhammad;Ali, Imran;Pu, YoungGun;Hwang, Keum Cheol;Yang, Youngoo;Kim, Dong In;Lee, Kang-Yoon
    • Journal of Semiconductor Engineering
    • /
    • v.1 no.1
    • /
    • pp.13-30
    • /
    • 2020
  • Radio frequency (RF) energy harvesting technology have become a reliable and promising alternative to extend the lifetime of power-constrained wireless networks by eliminating the need for batteries. This emerging technology enables the low-power wireless devices to be self-sustaining and eco-friendly by scavenging RF energy from ambient environment or dedicated energy sources. These attributes make RF energy harvesting technology feasible and attractive to an extended range of applications. However, despite being the most reliable energy harvesting technology, there are several challenges (especially power conversion efficiency, output DC voltage and sensitivity) poised for the implementation of RF energy harvesting systems. In this article, a detailed literature on RF energy harvesting technology has been surveyed to provide guidance for RF energy harvesters design. Since signal strength of the received RF power is limited and weak, high efficiency state-of-the-art RF energy harvesters are required to design for providing sufficient DC supply voltage to wireless networks. Therefore, various designs and their trade-offs with comprehensive analysis for RF energy harvesters have been discussed. This paper can serve as a good reference for the researchers to catch new research topics in the field of RF energy harvesting.

Needs Assessment for Web-based Self-management Program by the Nutrition Knowledge Levels of Diabetic Patients (당뇨환자의 영양지식수준에 따른 자가관리 현황 및 웹베이스 영양관리 프로그램 개발에 관한 요구도 조사)

  • Ahn, Yun;Bae, Jea-Hurn;Youn, Jung-Eun;Kim, Hee-Seon
    • Korean Journal of Community Nutrition
    • /
    • v.16 no.1
    • /
    • pp.155-168
    • /
    • 2011
  • This study was conducted to assess needs of self-management nutrition program for diabetic patients. The survey was conducted among 100 diabetic patients, and the mean age of the subjects was 54.2 years old. Thirty three percent of the subjects were diagnosed diabetes less than 2 years ago. The average nutrition knowledge score about diabetes was 10.2 point, and percentages of correct answers were very high in 'foods rich in fiber' (97.0%), 'relevance of exercise and insulin' (97.0%), 'quantity of insulin injection' (91.0%), and 'diabetes menu' (91.0%). The sources of nutrition information were hospitals/healthcare centers (56.1%), TV/radio (19.2%), and internet (13.1%). Sixty nine percent of the subjects have experienced nutrition education on subjects as 'menu planning skills'(22.4%), 'selecting foods' (22.4%), 'relevance of blood glucose and eating foods' (21.5%) by personal counseling (54.4%). The total score of eating behavior was higher after diagnosed diabetes (35.3) than before (30.0) (p < 0.001). The preferred topics in developing diabetes nutrition information websites were 'diabetes mellitus', 'relevance of blood glucose and foods', and 'selecting foods for diabetes'. The subjects wanted the websites developed by 'using mainly illustrations, pictures, tables' (22.8%) and 'using simple design' (19.6%). The preferred contents in developing diabetes self-management nutrition program were 'dietary life diagnosis', 'chronic disease risk diagnosis', 'calorie control by selecting foods and cooking skills', and 'dietary assessment'. In designing the program, the subjects' most wanted designs were 'be handy and simple in using' (29.3%), 'using simple design' (17.9%), and 'using mainly illustrations, pictures, tables' (15.7%).

Performance Evaluation of a Wireless Home Network in the Presence of Co-Channel Interference (동일채널간섭이 존재하는 홈 네트워크에서의 성능 평가)

  • Roh, Jae-Sung;Ye, Hui-Jin
    • Journal of Digital Contents Society
    • /
    • v.8 no.4
    • /
    • pp.491-497
    • /
    • 2007
  • RPersonal area networking technology is becoming increasingly important in enabling useful wireless home applications. For example, Bluetooth and IEEE 802.11b standards are the most commonly deployed technologies for wireless home applications. However, because both standards share the same unlicensed ISM (Industrial, Scientific, Medical) radio spectrum, severe interference is inevitable and performance can be impaired significantly when heterogeneous devices using the two technologies come into close proximity. In this paper, we research Gaussian FSK Bluetooth system, which is an open specification technology for short-range wireless connectivity between electronic devices. In this paper, we analyzes the effects of co-channel interference on the performance of a Gaussian FSK Bluetooth system. Performance criteria used in the study are the signal to interference power ratio (SIR), interference index, and the bit error rate (BER) in the wireless channel. The effect of co-channel interference from various sources on the performance of a Gaussian FSK Bluetooth system is analyzed using an IGA(Impulsive Gaussian Approximation) method, and these quantities are plotted against Eb/No, $\rho$ and SIR for various channel conditions in figures.

  • PDF