• Title/Summary/Keyword: Russell

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DISCOVERY OF WHITE DWARFS IN THE GLOBULAR CLUSTERS M13 AND M22 USING HST ACS PHOTOMETRIC DATA

  • CHO, DONG-HWAN;YOON, TAE SEOG;LEE, SANG-GAK;Sung, HYUN-IL
    • Journal of The Korean Astronomical Society
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    • v.48 no.6
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    • pp.333-341
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    • 2015
  • A search for hot and bright white dwarfs (WDs) in the Milky Way globular clusters M13 (NGC 6205) and M22 (NGC 6656) is carried out using the deep and homogeneous V I photometric catalog of Anderson et al. and and Sarajedini et al., based on data taken with the ACS/WFC aboard the Hubble Space Telescope (HST). V versus V − I color-magnitude diagrams (CMDs) of M13 and M22 are constructed and numerous spurious detections are rejected according to their photometric quality parameters qfit(V ) and qfit(I). In the case of M13, further radial restriction is applied to reject central stars with higher photometric errors due to central crowding. From each resultant V versus V −I CMD, sixteen and thirteen WD candidates are identified in M13 and M22, respectively. They are identified as stellar objects in the accompanying ACS/WFC images and are found to be randomly distributed across the central regions of M13 and M22. Their positions in the CMDs are in the bright part of the DA WD cooling sequences indicating that they are true WDs. In order to confirm their nature, follow-up spectroscopic observations are needed.

SEJONG OPEN CLUSTER SURVEY (SOS) - V. THE ACTIVE STAR FORMING REGION SH 2-255 - 257

  • LIM, BEOMDU;SUNG, HWANKYUNG;HUR, HYEONOH;LEE, BYEONG-CHEOL;BESSELL, MICHAEL S.;KIM, JINYOUNG S.;LEE, KANG HWAN;PARK, BYEONG-GON;JEONG, GWANGHUI
    • Journal of The Korean Astronomical Society
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    • v.48 no.6
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    • pp.343-355
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    • 2015
  • There is much observational evidence that active star formation is taking place in the Hii regions Sh 2-255 – 257. We present a photometric study of this star forming region (SFR) using imaging data obtained in passbands from the optical to the mid-infrared, in order to study the star formation process. A total of 218 members were identified using various selection criteria based on their observational properties. The SFR is reddened by at least E(B −V ) = 0.8 mag, and the reddening law toward the region is normal (RV = 3.1). From the zero-age main sequence fitting method it is confirmed that the SFR is 2.1 ± 0.3 kpc from the Sun. The median age of the identified members is estimated to be about 1.3 Myr from a comparison of the Hertzsprung-Russell diagram (HRD) with stellar evolutionary models. The initial mass function (IMF) is derived from the HRD and the near-infrared (J, J −H) color-magnitude diagram. The slope of the IMF is about Γ = −1.6 ± 0.1, which is slightly steeper than that of the Salpeter/Kroupa IMF. It implies that low-mass star formation is dominant in the SFR. The sum of the masses of all the identified members provides the lower limit of the cluster mass (169M). We also analyzed the spectral energy distribution (SED) of pre-main sequence stars using the SED fitting tool of Robitaille et al., and confirm that there is a significant discrepancy between stellar mass and age obtained from two different methods based on the SED fitting tool and the HRD.

Study on Heart Rate Variability and PSD Analysis of PPG Data for Emotion Recognition (감정 인식을 위한 PPG 데이터의 심박변이도 및 PSD 분석)

  • Choi, Jin-young;Kim, Hyung-shin
    • Journal of Digital Contents Society
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    • v.19 no.1
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    • pp.103-112
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    • 2018
  • In this paper, we propose a method of recognizing emotions using PPG sensor which measures blood flow according to emotion. From the existing PPG signal, we use a method of determining positive emotions and negative emotions in the frequency domain through PSD (Power Spectrum Density). Based on James R. Russell's two-dimensional prototype model, we classify emotions as joy, sadness, irritability, and calmness and examine their association with the magnitude of energy in the frequency domain. It is significant that this study used the same PPG sensor used in wearable devices to measure the top four kinds of emotions in the frequency domain through image experiments. Through the questionnaire, the accuracy, the immersion level according to the individual, the emotional change, and the biofeedback for the image were collected. The proposed method is expected to be various development such as commercial application service using PPG and mobile application prediction service by merging with context information of existing smart phone.

IDENTIFICATION OF LUMINOUS WHITE DWARF CANDIDATES IN THE GLOBULAR CLUSTERS M13 AND M22 USING HST ACS PHOTOMETRIC DATA

  • CHO, DONG-HWAN;YOON, TAE SEOG;LEE, SANG-GAK;SUNG, HYUN-IL
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.265-266
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    • 2015
  • A search for luminous white dwarfs (WDs) in several nearby Galactic globular clusters (GCs) was carried out using the deep and homogeneous photometric catalog of Galactic GCs taken with the ACS/WFC aboard the Hubble Space Telescope (HST) by Sarajedini et al. and Anderson et al- It resulted in the identification of luminous WD candidates in the GCs M13 (NGC 6205) and M22 (NGC 6656). The purpose of the present study is to identify luminous WDs in the deep and homogeneous V versus V - I color-magnitude diagrams (CMDs) of several nearby Galactic GCs taken with the ACS/WFC aboard the HST. Using photometric data for the GCs M13 and M22 that are now in the public domain, the V versus V - I CMDs of the GCs M13 and M22 were constructed. Many spurious detections in the CMDs were removed using the photometric quality parameters qfit(V) and qfit(I), and a radial restriction was applied to the CMDs to remove the central stars with higher photometric errors due to central crowding. From each resultant V versus V - I CMD of the GCs M13 and M22, a dozen or so luminous WD candidates were identified. They were confirmed as stellar objects in the accompanying ACS/WFC images and their positions in the CMDs were in the bright part of the DA WD cooling curve. Therefore, the luminous WD candidates in the GCs M13 and M22 seem to be true luminous WDs, and spectroscopic observations are needed to confirm their true identity.

Development of an optimal protocol to induce capacitation of boar spermatozoa in vitro

  • Seung-Ik Jang;Jae-Hwan Jo;Eun-Ju Jung;Woo-Jin Lee;Ju-Mi Hwang;Jeong-Won Bae;Woo-Sung Kwon
    • Journal of Animal Reproduction and Biotechnology
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    • v.37 no.4
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    • pp.285-291
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    • 2022
  • In 1951, Colin Russell Austin and Min Chueh Chang identified "capacitation", a special process involving ejaculated spermatozoa in the female reproductive tract. Capacitation is a phenomenon that occurs in vivo, but almost all knowledge of capacitation has been obtained from in vitro studies. Therefore, numerous trials have been performed to establish in vitro capacitation methods for various studies on reproduction. Although a series of studies have been conducted to develop an optimal protocol for inducing capacitation, most have focused on identifying the appropriate chemical compounds to induce the capacitation of boar spermatozoa in vitro. Therefore, the purpose of this study was to identify the optimal incubation time for inducing capacitation in vitro. Duroc semen was incubated for various periods (60, 90, and 120 min) to induce capacitation. Sperm function (sperm motility, motion kinematic parameters, and capacitation status) was evaluated. The results showed that total sperm motility, rapid sperm motility, progressive sperm motility, curvilinear velocity, and average path velocity significantly decreased in a time-dependent manner. However, the capacitation status did not show any significant changes. Taken together, these results indicate that an incubation time of more than 60 min suppresses sperm motility and motion kinematic parameters. Therefore, we suggest that 60 min may be the best incubation time to induce capacitation without negative effects on sperm motility and motion kinematics in boar spermatozoa in vitro.

Constructing Southeast Asia and the Middle East: Two Corners of the "Victorian World"

  • Keck, Stephen L.
    • SUVANNABHUMI
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    • v.7 no.2
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    • pp.27-56
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    • 2015
  • How should we conceptualize regions? What is the context in which new approaches to regional study take place? What is the role of historical change in the reconceptualization of regions or areas? This article addresses this issue by using two case studies to shed light on the history of regional study by comparing some of the ways in which the Middle East and Southeast Asia have been conceptualized. Accordingly, the discussion traces the ways in which these areas were understood in the 19th century by highlighting the ideas of a number of influential Victorian thinkers. The Victorians are useful because not only did British thinkers play critical roles in the shaping of modern patterns of knowledge, but their empire was global in scope, encompassing parts of both Southeast Asia and the Middle East. However, the Victorians regarded these places quite differently: Southeast Asia was frequently described as "Further India" and the Middle East was the home of the Ottoman Empire. Both of these places were at least partly understood in relation to the needs of British policy-makers, who tended to focus most of their efforts according to the needs of India-which was their most important colonial possession. The article exhibits the connections between the "Eastern Question" and end of the Ottoman Empire (and the political developments which followed) led to the creation of the concept of "Middle East". With respect to Southeast Asia, attention will be devoted to the works of Alfred Russell Wallace, Hugh Clifford, and others to see how "further India" was understood in the 19th century. In addition, it is clear that the successful deployment of the term "Southeast Asia" reflected the political needs of policy makers in wake of decolonization and the Cold War. Finally, by showing the constructive nature of regions, the article suggests one possible new path for students of Southeast Asia. If the characterization of the region is marked by arbitrary factors, it may actually point to a useful avenue of enquiry, a hermeneutic of expedience. Emphasis on the adaptive and integrative features of lived realities in Southeast Asia may well be a step beyond both the agendas of "colonial knowledge" and anti-colonial nationalism.

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A Deep Optical Survey of Young Stars in the Carina Nebula. I. UBVRI Photometric Data and Fundamental Parameters

  • Hyeonoh Hur;Beomdu Lim;Moo-Young Chun
    • Journal of The Korean Astronomical Society
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    • v.56 no.1
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    • pp.97-115
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    • 2023
  • We present the deep homogeneous UBV RI photometric data of 135,071 stars down to V ~ 23 mag and I ~ 22 mag toward the Carina Nebula. These stars are cross-matched with those from the previous surveys in the X-ray, near-infrared, and mid-infrared wavelengths as well as the Gaia Early Data Release 3 (EDR3). This master catalog allows us to select reliable members and determine the fundamental parameters distance, size, stellar density of stellar clusters in this star-forming region. We revisit the reddening toward the nebula using the optical and the near-infrared colors of early-type stars. The foreground reddening [E(B-V)fg] is determined to be 0.35 ± 0.02, and it seems to follow the standard reddening law. On the other hand, the total-to-selective extinction ratio of the intracluster medium (RV,cl) decreases from the central region (Trumpler 14 and 16, RV,cl ~ 4.5) to the northern region (Trumpler 15, RV,cl ~ 3.4). It implies that the central region is more dusty than the northern region. We find that the distance modulus of the Carina Nebula to be 11.9 ± 0.3 mag (d = 2.4 ± 0.35 kpc) using a zero-age main-sequence fitting method, which is in good agreement with that derived from the Gaia EDR3 parallaxes. We also present the catalog of 3,331 pre-main-sequence (PMS) members and 14,974 PMS candidates down to V ~ 22 mag based on spectrophotometric properties of young stars at infrared, optical, and X-ray wavelengths. From the spatial distribution of PMS members and PMS candidates, we confirm that the member selection is very reliable down to faint stars. Our data will have a legacy value for follow-up studies with different scientific purposes.

Five-year follow-up after pancreatoduodenectomy performed for malignancy: A single-centre study

  • Thomas Brendon Russell;Peter Lawrence Zaki Labib;Somaiah Aroori
    • Annals of Hepato-Biliary-Pancreatic Surgery
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    • v.27 no.1
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    • pp.76-86
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    • 2023
  • Backgrounds/Aims: The aim of this study was to describe short- and long-term outcomes of patients who underwent pancreatoduodenectomy (PD) at a typical United Kingdom hepatopancreatobiliary unit. Methods: A retrospective analysis of all PD patients with histologically-confirmed pancreatic ductal adenocarcinoma (PDAC), ampullary adenocarcinoma (AA), or distal cholangiocarcinoma (CC) from September 1st, 2006 to May 31st, 2015 was carried out. The following information was obtained: demographics, comorbidities, preoperative investigations, neoadjuvant treatment, operative details, postoperative management, complications, adjuvant treatment, five-year recurrence, and five-year survival. Effects of selected preoperative variables on short- and long-term outcomes were investigated. Results: Of 271 included patients, 57.9% had PDAC, 25.8% had AA, and 16.2% had CC. In total, 67.9% experienced morbidity and 17.3% developed a Clavien-Dindo grade ≥ III complication. The 90-day mortality was 3.3%. Clinically-relevant postoperative pancreatic fistula, bile leak, gastrojejunal leak, postpancreatectomy haemorrhage and delayed gastric emptying affected 8.1%, 4.1%, 0.0%, 9.2%, and 19.9% of patients, respectively. American Society of Anesthesiologists grade III-VI correlated with overall morbidity (p = 0.002) and major morbidity (p = 0.009), but not 90-day mortality or five-year survival. The same pattern was observed in patients with a preoperative serum bilirubin > 29 µmol/L and/or a neutrophil/lymphocyte ratio > 3.1. Five-year cancer recurrence and five-year survival were 68.3% and 22.5%, respectively. PDAC patients had higher five-year recurrence but lower five-year survival rates (both p = 0.001). Conclusions: In our series, the majority of patients experienced a complication. However, few patients experienced major morbidity. Surgical risk factors did not affect five-year survival.

The single-stage management of bile duct stones is underutilised: A prospective multicentre cohort study with a literature review

  • Andrei Tanase;Thomas Brendon Russell;Timothy Platt;Ewen Alexander Griffiths;Somaiah Aroori;CholeS study group, West Midlands Research Collaborative
    • Annals of Hepato-Biliary-Pancreatic Surgery
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    • v.26 no.4
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    • pp.333-338
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    • 2022
  • Backgrounds/Aims: Bile duct stones (BDS) can be managed either prior to laparoscopic cholecystectomy (LC) using endoscopic retrograde cholangiopancreatography (ERCP) or with laparoscopic bile duct exploration (LBDE) at the time of LC. The latter is underutilised. The aim of this study was to use the dataset of the previously performed CholeS study to investigate LBDE hospital volumes, LBDE-to-LC rates, and LBDE outcomes. Methods: Data from 166 United Kingdom/Republic of Ireland hospitals were used to study the utilisation of LBDE in LC patients. Results: Of 8,820 LCs performed, 932 patients (10.6%) underwent preoperative ERCP and 256 patients (2.9%) underwent LBDE. Of the 256 patients who underwent LBDE, 73 patients (28.5%) had undergone prior ERCP and 112 patients (43.8%) had undergone prior magnetic resonance cholangiopancreatography. Fifteen (9.0%) of the 166 included hospitals performed less than five LBDEs in the two-month study period. LBDEs were mainly performed by upper gastrointestinal surgeons (84.4%) and colorectal surgeons (10.0%). Eighty-seven percent of the LBDEs were performed by consultants and 13.0% were performed by trainees. The laparoscopic-to-open conversion rate was 12.5%. The median operation time was 111 minutes (range: 75-155 minutes). Median hospital stay was 6 days (range: 4-11 days) for emergency LBDEs and 1 day (range: 1-4 days) for elective LBDEs. Overall morbidity was 21.5%. Bile leak rate was 5.3%. Thirty-day readmission and mortality rates were 12.1% and 0.4%, respectively. Conclusions: The single-stage approach to managing BDS was underutilised. An additional prospective study with a longer study period is needed to verify this finding.

Image Color, Brightness, Saturation Similarity Validation Study of Emotion Computing (이미지 색상, 명도, 채도 감성컴퓨팅의 유사성 검증 연구)

  • Lee, Yean-Ran
    • Cartoon and Animation Studies
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    • s.40
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    • pp.477-496
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    • 2015
  • Emotional awareness is the image of a person is represented by different tendencies. Currently, the emotion computing to objectively evaluate the emotion recognition research is being actively studied. However, existing emotional computing research has many problems to run. First, the non-objective in emotion recognition if it is inaccurate. Second, the correlation between the emotion recognition is unclear points. So to test the regularity of image sensitivity to the need of the present study is to control emotions in the computing system. In addition, the screen number of the emotion recognized for the purpose of this study, applying the method of objective image emotional computing system and compared with a similar degree of emotion of the person. The key features of the image emotional computing system calculates the emotion recognized as numbered digital form. And to study the background of emotion computing is a key advantage of the effect of the James A. Russell for digitization of emotion (Core Affect). Pleasure emotions about the core axis (X axis) of pleasure and displeasure, tension (Y-axis) axis of tension and relaxation of emotion, emotion is applied to the computing research. Emotional axis with associated representative sensibility very happy, excited, elated, happy, contentment, calm, relaxing, quiet, tired, helpless, depressed, sad, angry, stress, anxiety, pieces 16 of tense emotional separated by a sensibility ComputingIt applies. Course of the present study is to use the color of the color key elements of the image computing formula sensitivity, brightness, and saturation applied to the sensitivity property elements. Property and calculating the rate sensitivity factors are applied to the importance weight, measured by free-level sensitivity score (X-axis) and the tension (Y-axis). Emotion won again expanded on the basis of emotion crossed point, and included a representative selection in Sensibility size of the top five ranking representative of the main emotion. In addition, measuring the emotional image of a person with 16 representative emotional score, and separated by a representative of the top five senses. Compare the main representative of the main representatives of Emotion and Sensibility people aware of the sensitivity of the results to verify the similarity degree computing emotion emotional emotions depending on the number of representative matches. The emotional similarity computing results represent the average concordance rate of major sensitivity was 51%, representing 2.5 sensibilities were consistent with the person's emotion recognition. Similar measures were the degree of emotion computing calculation and emotion recognition in this study who were given the objective criteria of the sensitivity calculation. Future research will need to be maintained weight room and the study of the emotional equation of a higher concordance rate improved.