Analysis of historical meteor and meteor shower records: Korea, China, and Japan

We have compiled and analyzed historical Korean meteor and meteor shower records in three Korean official history books, Samguksagi which covers the three Kingdoms period (57 B.C -- A.D. 935), Goryeosa of Goryeo dynasty (A.D. 918 -- 1392), and Joseonwangjosillok of Joseon dynasty (A.D. 1392 -- 1910). We have found 3861 meteor and 31 meteor shower records. We have confirmed the peaks of Perseids and an excess due to the mixture of Orionids, north-Taurids, or Leonids through the Monte-Carlo test. The peaks persist from the period of Goryeo dynasty to that of Joseon dynasty, for almost one thousand years. Korean records show a decrease of Perseids activity and an increase of Orionids/north-Taurids/Leonids activity. We have also analyzed seasonal variation of sporadic meteors from Korean records. We confirm the seasonal variation of sporadic meteors from the records of Joseon dynasty with the maximum number of events being roughly 1.7 times the minimum. The Korean records are compared with Chinese and Japanese records for the same periods. Major features in Chinese meteor shower records are quite consistent with those of Korean records, particularly for the last millennium. Japanese records also show Perseids feature and Orionids/north-Taurids/Leonids feature, although they are less prominent compared to those of Korean or Chinese records.Comment: 29 pages, 7 figures. To appear in Icaru

I-129 Waste form Using Bi-Zn-P-Oxide Glass

AbstractI-129 is a problematic nuclide generated from the recycling of spent fuel by pyroprocess. Gaseous form of radiogenic iodine is trapped by using silver exchanged zeolite (AgX) at Korea Atomic Energy Research Institute (KAERI). We developed the low melting temperature glass system based on Bi2O3-P2O5 composition. Various additives were added to modify glass properties. We found that ingots containing AgI are formed with ZnO, CaCO3, MgO, and Na2CO3 at around 600°C. Analysis of microstructure and chemical durability revealed that AgI was encapsulated by glass matrix and formation of AgI compound is meaningful in fabricating iodine waste form

Molecular methods for genomic analyses of variant PML-RARA or other RARA-related chromosomal translocations in acute promyelocytic leukemia

TO THE EDITOR: We read an interesting paper by Palta et al. in a recent issue of the Korean Journal of Hematology titled, "ZBTB16-RARA variant of acute promyelocytic leukemia with tuberculosis: a case report and review of literature" [1]. We would like to add some comments to their article and suggest additional molecular methods to confirm variant translocations in acute promyelocytic leukemia (APL)...

Enhancing Biodiversity through Self-Regulation in Large Ecosystems

The competitive exclusion principle (CEP) is a fundamental concept in the niche theory, which posits that the number of available resources constrains the coexistence of species. While the CEP offers an intuitive explanation for coexistence, it has been challenged by counterexamples observed in nature. One prominent counterexample is the phytoplankton community, known as the paradox of the plankton. Diverse phytoplankton species coexist in the ocean even though they demand a limited number of resources. To shed light on this remarkable biodiversity in large ecosystems quantitatively, we consider self-regulation into the generalized MacArthur's consumer-resource model and study the relative diversity, the number ratio between coexisting consumers and resource kinds. By employing the cavity method and generating functional analysis, we analytically show how the bounds of the relative diversity can exceed unity and its dependency on the strength of the self-regulation. We confirm the analysis with numerical simulations and reveal that the self-regulation suppresses the emergence of dominant species, thereby fostering high biodiversity. Furthermore, we study the effect of the self-regulation on different environments and show that the effect relies on the environmental condition. Our work presents a comprehensive framework within the niche theory that encompasses the CEP and its counterexamples by introducing the role of self-regulation.Comment: 34 pages (including supplementary material), 24 figures (4 figures in main, 20 figures in SM

Korean Nova Records in A.D. 1073 and A.D. 1074: R Aquarii

R Aqr is known to be a symbiotic binary system with an associated extended emission nebula, possibly produced by a historic outburst. To find the associated historic records, we searched for and compiled all 'Guest Star' and 'Peculiar Star' records in three Korean 'official' history books that cover almost two thousand years, Samguksagi, Goryeosa, Joseonwangjosillok. In addition to the record of A.D. 1073, previously noted by Li (1985), we have found in Goryeosa another candidate record of A.D. 1074, which has the same positional description as that of A.D. 1073 with an additional brightness description. We examined various aspects of the two records and conclude that they both are likely to be the records of outburst of R Aqr. This means that there were two successive outbursts in A.D. 1073 and in A.D. 1074, separated by approximately one year. Based on these records, we estimate the distance to R Aqr to be 273 pc if the expansion of the nebula has been at a constant rate. The brightness record of A.D. 1074 corresponds to the absolute magnitude at outburst of M_(outburst) = -6.2 mag. ~ -5.2 mag. at this distance. The two Korean records associated with R Aqr may provide astronomically meaningful constraints to the outburst model of R Aqr and the formative process of its nebulosity.Comment: 10 pages, 2 figures, 1 appendix. To appear in Astronomy and Astrophysic

Effects of Acupuncture on Alzheimer’s Disease in Animal-Based Research

Alzheimer’s disease (AD) is a chronic neurodegenerative disease characterized by the accumulation of amyloid beta (Aβ) plaques, neurofibrillary tangles, and severe functional deficits in the brain. The pathogenesis and treatment of AD remain topics of investigation and significant global socioeconomic issues. The effect of complementary medicine has been investigated in managing AD. Acupuncture, a form of therapy practiced for more than 3000 years, has shown positive effects on several neurological disorders including AD. Animal studies have evaluated the specific utility and neuropathological mechanisms addressed by acupoint manipulation; however, no study has summarized the relationships among different acupoints and their therapeutic effects in the context of AD. Therefore, we reviewed the effects of acupuncture at different acupoints in animal models of AD. In general, acupuncture produced therapeutic benefits in rodent models of AD. Studies demonstrate the utility of GV20 as a valuable acupoint for electroacupuncture and manual acupuncture. GV20 stimulation suppresses Aβ generation, improves glucose metabolism, and attenuates neuropathological features in various disease models. However, a lack of sufficient evidence in preclinical and clinical studies makes these results controversial. Additional studies are required to confirm the exact utility of specific acupoints in clinically managing AD