443 research outputs found

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    Abstract The gravitational waves (GW170817) produced during a binary neutron star inspiral, followed by a gamma-ray burst (GRB 170817A) and afterglows from X-ray to radio wavelength, were observed. By combining the distance obtained from gravitational waves with the red shift obtained from electromagnetic waves, even the Hubble constant was estimated. This indicates the start of new era of multimessenger astronomy. In addition to the masses of inspiralling neutron stars, the tidal deformability, which depends on the inner structures of neutron stars, has been estimated from gravitational waves. This confirms that even strong interactions can be tested by using gravitational waves. In this article, we review the effect of the tidal deformability of neutron stars on the gravitational waves produced during the inspiral process and discuss the implications of the detected tidal deformability for the neutron star's equations of state

    Strengthening the role of pediatric emergency centers in Korea

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    Since 2016, the pediatric emergency centers (PECs) have been selected by the Korean Ministry of Health and Welfare, but there are still many problems in their designation and operation. The authors, affiliated with the policy research team in the Korean Society of Pediatric Emergency Medicine, sought to identify the current status and plans for improvement of PECs in Korea. The problems in the designation and operation are the disproportionate regional distribution of the PECs, financial difficulties in meeting the designation criteria, and recruitment of dedicated pediatric emergency specialists. To improve this, it is necessary to designate additional PECs and analyze the appropriateness of insurance cost, to strengthen the role other than the community practice, and to reinforce back-up treatment by pediatric sub-specialists in PECs

    Glomangiomyoma of the Trachea

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    A glomus tumor is an uncommon soft tissue tumor that is most commonly found in the subungual area and a glomus originating in the trachea is extremely rare. Histologically and ultrastructurally, these tumors have been divided into three subtypes: classic glomus tumors, glomangiomas, and glomangiomyomas. Glomangiomyomas account for less than 10% of all glomus tumors and are the least common type. We report a case of a 54-year-old man with glomangiomyoma of the trachea who presented with stridor. We treated the tumor by segmental resection and primary repair via a transcervical approach

    Synchrotron x-ray imaging visualization study of capillary-induced flow and critical heat flux on surfaces with engineered micropillars

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    Over the last several decades, phenomena related to critical heat flux (CHF) on structured surfaces have received a large amount of attention from the research community. The purpose of such research has been to enhance the safety and efficiency of a variety of thermal systems. A number of theories have been put forward to explain the key CHF enhancement mechanisms on structured surfaces. However, these theories have not been confirmed experimentally because of limitations in the available visualization techniques and the complexity of the phenomena. To overcome these limitations and elucidate the CHF enhancement mechanism on the structured surfaces, we introduce synchrotron x-ray imaging with high spatial (similar to 2 mu m) and temporal (similar to 20,000 Hz) resolutions. This technique has enabled us to confirm that capillary-induced flow is the key CHF enhancement mechanism on structured surfaces.11Ysciescopu

    Effects of Marital Status and Income on Hypertension: The Korean Genome and Epidemiology Study (KoGES)

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    Objectives: This study aimed to analyze the associations of income, marital status, and health behaviors with hypertension in male and female over 40 years of age in the Korea. Methods: The data were derived from the Korean Genome and Epidemiology Study (KoGES; 4851-302) which included 211 576 participants. To analyze the relationships of income, marital status, and health behaviors with hypertension in male and female over 40 years of age, multiple logistic regression was conducted with adjustments for these variables. Results: The prevalence of hypertension increased linearly as income decreased. The odds ratio for developing hypertension in people with an income of <0.5 million Korean won (KRW) compared to ≥6.0 million KRW was 1.55 (95% confidence interval [CI], 1.25 to 1.93) in the total population, 1.58 (95% CI, 1.27 to 1.98) in male, and 1.07 (95% CI, 0.35 to 3.28) in female. The combined effect of income level and marital status on hypertension was significant. According to income level and marital status, in male, low income and divorce were most associated with hypertension (1.76 times; 95% CI, 1.01 to 3.08). However, in female, the low-income, married group was most associated with hypertension (1.83 times; 95% CI, 1.71 to 1.97). Conclusions: The results of this study show that it is necessary to approach male and female marital status separately according to income in health policies to address inequalities in the prevalence of hypertension

    Evaluation for Damaged Degree of Vegetation by Forest Fire Using LiDAR and Digital Aerial Photograph

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    The amount of vegetation physically damaged by forest fire can be evaluated using lidar (Light Detection And Ranging) data because the loss of canopy height and width by forest fire can be relevant to the number of points transmitted to the ground through the canopy of the damaged forest. On the other hand, the biological damage of vegetation caused by forest fire can be obtained from the Normalized Difference Vegetation Index (NDVI), which determines the vegetation vitality. In this study, the degree of physical damage from the lidar data was classified into serious physical damage (SPD) and light physical damage (LPD). The degree of biological damage using NDVI was likewise classified into serious biological damage (SBD) and light biological damage (LBD). Finally, the damaged area was graded into four categories: (a) SPD and SBD, (b) LPD and SBD, (c) SPD and LBD, and (d) LPD and LBD. The accuracy assessment for the area classified into four grades showed an overall accuracy of 0.74, and a kappa value of 0.61 which provides improvement over previous works

    Kaon condensation in neutron stars with Skyrme-Hartree-Fock models

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    We investigate nuclear-matter equations of state in neutron stars with kaon condensation. It is generally known that the existence of kaons in neutron star makes the equation of state soft so that the maximum mass of a neutron star is not likely to be greater than 2.0M, the maximum mass constrained by current observations. With existing Skyrme force model parameters, we calculate nuclear equations of state and check the possibility of kaon condensation in the core of neutron stars. The results show that, even with the kaon condensation, the nuclear equation of state satisfies both the maximum mass and the allowed ranges of mass and radius.open0

    Chronic Idiopathic Myelofibrosis Presenting as Cauda Equina Compression due to Extramedullary Hematopoiesis: A Case Report

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    Extramedullary hematopoiesis (EMH) is occasionally reported in idiopathic myelofibrosis and is generally found in the liver, spleen, and lymph nodes several years after diagnosis. Myelofibrosis presenting as spinal cord compression, resulting from EMH tissue is very rare. A 39-yr-old man presented with back pain, subjective weakness and numbness in both legs. Sagittal magnetic resonance imaging showed multiple anterior epidural mass extending from L4 to S1 with compression of cauda equina and nerve root. The patient underwent gross total removal of the mass via L4, 5, and S1 laminectomy. Histological analysis showed islands of myelopoietic cells surrounded by fatty tissue, consistent with EMH, and bone marrow biopsy performed after surgery revealed hypercellular marrow and megakaryocytic hyperplasia and focal fibrosis. The final diagnosis was chronic idiopathic myelofibrosis leading to EMH in the lumbar spinal canal. Since there were no abnormal hematological findings except mild myelofibrosis, additional treatment such as radiothepary was not administered postoperatively for fear of radiotoxicity. On 6 month follow-up examination, the patient remained clinically stable without recurrence. This is the first case of chronic idiopathic myelofibrosis due to EMH tissue in the lumbar spinal canal in Korea

    Dependence of GCRs influx on the Solar North-South Asymmetry

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    We investigate the dependence of the amount of the observed galactic cosmic ray (GCR) influx on the solar North-South asymmetry using the neutron count rates obtained from four stations and sunspot data in archives spanning six solar cycles from 1953 to 2008. We find that the observed GCR influxes at Moscow, Kiel, Climax and Huancayo stations are more suppressed when the solar activity in the southern hemisphere is dominant compared with when the solar activity in the northern hemisphere is dominant. Its reduction rates at four stations are all larger than those of the suppression due to other factors including the solar polarity effect on the GCR influx. We perform the student's t-test to see how significant these suppressions are. It is found that suppressions due to the solar North-South asymmetry as well as the solar polarity are significant and yet the suppressions associated with the former are larger and more significant.Comment: 17 pages, 3figures, accepted to JAST

    Effects of exercise on obesity-induced mitochondrial dysfunction in skeletal muscle

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    Obesity is known to induce inhibition of glucose uptake, reduction of lipid metabolism, and progressive loss of skeletal muscle function, which are all as- sociated with mitochondrial dysfunction in skeletal muscle. Mitochondria are dy- namic organelles that regulate cellular metabolism and bioenergetics, including ATP production via oxidative phosphorylation. Due to these critical roles of mitochon- dria, mitochondrial dysfunction results in various diseases such as obesity and type 2 diabetes. Obesity is associated with impairment of mitochondrial function (e.g., decrease in O2 respiration and increase in oxidative stress) in skeletal muscle. The bal- ance between mitochondrial fusion and fission is critical to maintain mitochondrial homeostasis in skeletal muscle. Obesity impairs mitochondrial dynamics, leading to an unbalance between fusion and fission by favorably shifting fission or reducing fusion proteins. Mitophagy is the catabolic process of damaged or unnecessary mito- chondria. Obesity reduces mitochondrial biogenesis in skeletal muscle and increases accumulation of dysfunctional cellular organelles, suggesting that mitophagy does not work properly in obesity. Mitochondrial dysfunction and oxidative stress are reported to trigger apoptosis, and mitochondrial apoptosis is induced by obesity in skeletal muscle. It is well known that exercise is the most effective intervention to protect against obesity. Although the cellular and molecular mechanisms by which exercise protects against obesity-induced mitochondrial dysfunction in skeletal mus- cle are not clearly elucidated, exercise training attenuates mitochondrial dysfunction, allows mitochondria to maintain the balance between mitochondrial dynamics and mitophagy, and reduces apoptotic signaling in obese skeletal muscle
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