• Korean Journal of Veterinary Research
• /
• v.59 no.3
• /
• pp.151-155
• /
• 2019

Equine influenza (EI) is the main cause of respiratory illness in equines across the globe and is caused by equine influenza A virus (EIV-A), which has impacted the equine industry internationally because of the marginal mortality and high morbidity. In the present study, the immune responses after equine influenza vaccination were evaluated in 4,144 horses in Korea using the hemagglutination inhibition (HI) assay. The equine influenza virus (EIV), A/equine/South Africa/4/03 (H3N8), was used as the antigen in the HI assay. The mean seropositive rates were 89.2% (97.4% in 2016, 77.6% in 2017, and 92.4% in 2018). This paper highlights the advances in understanding the effects of vaccines and control strategies for mitigating the emerging menace by EIV.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.04a
• /
• pp.78-78
• /
• 2019

Gnaphalium L. is a small herbaceous genus comprising up to 80 species in worldwide (Asia, North to South America, Africa, and Oceania). This genus is highly polymorphic which embrace uncommon broad morphological boundary, and thus further studies were needed to proper taxonomic delimitations for the genus and its relatives. Gnaphalium uliginosum L. was usually found in moist sites such as margins of lake, pond, reservoir, stream banks and paddy field. This squat plant is solely known species in Korean Gnaphalium. During the revisionary study of the tribe Gnaphalieae (Asteraceae) in Korea, however, we found several materials in domestic herbaria (e.g., SNU, KWNU) that identified as G. uliginosum or Gamochaeta pensylvanica (Willd.) Cabrera collected from central to northern Korea, but clearly differ to the morphology of G. uliginosum. The external morphology of the materials is seemingly the only feature at odds with G. uliginosum. However, its morphological characters such as tall erected stems (ca. 30cm), hairs on seeds and whitish tomentose hairs on the whole plants are easily distinguished from G. uliginosum, and rather it looks like G. tranzschelii Kirp. Although the name G. tranzschelii have been treated as synonym of G. uliginosum by several authors, its distinct morphology might be sufficient to separate to two independent taxa. Generally, the morphological polymorphisms and hybridization of G. uliginosum complicate the taxonomy of the species, and thus further investigation for their habitat, distribution and morphology were needed to their taxonomic entity.

• Journal of the Korean Mathematical Society
• /
• v.56 no.2
• /
• pp.539-558
• /
• 2019

An ideal of a commutative ring is called a d-ideal if it contains the annihilator of the annihilator of each of its elements. Denote by DId(A) the lattice of d-ideals of a ring A. We prove that, as in the case of f-rings, DId(A) is an algebraic frame. Call a ring homomorphism "compatible" if it maps equally annihilated elements in its domain to equally annihilated elements in the codomain. Denote by $SdRng_c$ the category whose objects are rings in which the sum of two d-ideals is a d-ideal, and whose morphisms are compatible ring homomorphisms. We show that $DId:\;SdRng_c{\rightarrow}CohFrm$ is a functor (CohFrm is the category of coherent frames with coherent maps), and we construct a natural transformation $RId{\rightarrow}DId$, in a most natural way, where RId is the functor that sends a ring to its frame of radical ideals. We prove that a ring A is a Baer ring if and only if it belongs to the category $SdRng_c$ and DId(A) is isomorphic to the frame of ideals of the Boolean algebra of idempotents of A. We end by showing that the category $SdRng_c$ has finite products.

• Journal of Astronomy and Space Sciences
• /
• v.36 no.3
• /
• pp.133-147
• /
• 2019

Challenging Minisatellite Payload (CHAMP) satellite magnetic data are used to investigate the latitudinal variation of the storm-time meso-scale field-aligned currents by defining a new metric called the FAC range. Three major geomagnetic storm events are considered. Alongside SymH, the possible contributions from solar wind dynamic pressure and interplanetary magnetic field (IMF) $B_Z$ are also investigated. The results show that the new metric predicts the latitudinal variation of FACs better than previous studies. As expected, the equatorward expansion and poleward retreat are observed during the storm main phase and recovery phase respectively. The equatorward shift is prominent on the northern duskside, at ${\sim}58^{\circ}$ coinciding with the minimum SymH and dayside at ${\sim}59^{\circ}$ compared to dawnside and nightside respectively. The latitudinal shift of FAC range is better correlated to IMF $B_Z$ in northern hemisphere dusk-dawn magnetic local time (MLT) sectors than in southern hemisphere. The FAC range latitudinal shifts responds better to dynamic pressure in the duskside northern hemisphere and dawnside southern hemisphere than in southern hemisphere dusk sector and northern hemisphere dawn sector respectively. FAC range exhibits a good correlation with dynamic pressure in the dayside (nightside) southern (northern) hemispheres depicting possible electrodynamic similarity at day-night MLT sectors in the opposite hemispheres.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.61.2-61.2
• /
• 2019

A total of 10,317 hours of the KMTNet telescope time were allocated for the predefined science programs, and 7,765 hours have been used for science exposures in Chile, Australia and South Africa last year. The success rate of science observation has increased from 70.7% to 75.3%, and the system operation rate has also increased from 97.6% to 99.6%. There were many improvements in mechanical parts of the dome structure and telescope system, and newly installed filter driers of the CCD camera increased the stability of the system by preventing contamination of oil in the gas line in advance. In order to prepare for the time domain astronomy and multi messenger astronomy era, a pilot program was designed and is now being tested. It targets for fast follow-up observations of optical transient events, however it runs during twilight times only so it does not interrupt any granted science program. A total of 32 SCI papers were published using the system in 2018 and it is a good indication of the high science performance of KMTNet. The selection process of the next observation programs starting from October 2020 and its timeline will be discussed in this meeting.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.5
• /
• pp.596-616
• /
• 2021

A global increase in fish consumption has led to a rapid expansion of aquaculture production, which has been linked to enhancing the spread of infectious diseases. Viral diseases can cause high mortality in many cultured fish species, posing a serious threat to the aquaculture industry. Infectious hematopoietic necrosis virus (IHNV) is one of the primary threats to aquacultured salmonid species, causing huge economic losses. Since the first report in cultured sockeye salmon Oncorhynchus nerka during the 1950s in North America, IHNV has spread to other regions, including Europe, Asia, South America, and Africa by transportation of infected fish and eggs, causing disease and increasing mortality in a wide variety of salmonid species. Here, we review existing information relevant to IHNV: its phylogenetic characteristics, origin, infection history, virulence determinants, susceptible hosts, vectors, and vaccine development. This review also addresses a possible cross-species transmission of IHNV to a new host, olive flounder Paralichthys olivaceus, a cultured fish of economic importance in East Asian countries.

• Economic and Environmental Geology
• /
• v.54 no.2
• /
• pp.213-232
• /
• 2021

Ore criteria at the Sheba Deposit indicate orogenic mineralization type. Rocks and mineral assemblages suggest low formation-temperature of green-schist facies. Pyrite found in two generations; Type1 is irregular grains, contains higher arsenic and gold contents, compared to the relatively younger phase Type2 pyrite, which is composed of euhedral grains, found adjacent to late quartz-carbonate veins or at rims of type1 pyrite. Two gold generations were identified; type1 found included in sulphides (mainly pyrite). The second gold type was remobilized (secondary) into free-lodes within silicates (mainly quartz). Gold fineness is high, as gold contains up to 95 wt. % Au, Ag up to 3.5 wt. %, and traces of Cu, Ni, and Fe. Pyrite type2 contains tiny mineral domains (rich in Al, Mn, Hg, Se, Ti, V, and Cr). Zoning, and replacement textures are common, suggesting multiple mineralization stages. The distribution and relationships of trace elements in pyrite type2 indicate three formation patterns: (1) Al, Mn, Hg, Se, Ti, V, Cr, and Sn are homogeneously distributed in pyrite, reflecting a synchronous formation. (2) As, Ni, Co, Zn, and Sb display heterogeneous distribution pattern in pyrite, which may indicate post-formation existence due to other activities. (3) Au and Ag show both distribution patterns within pyrite, suggesting that gold is found both in microscopic phases and as chemically bounded phase.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.2
• /
• pp.77-88
• /
• 2021

The stock markets in the BRICS (Brazil, Russia, India, China and South Africa) countries are the leading emerging markets globally. Therefore, it is pertinent to ascertain the critical drivers of stock market development in these economies. The currrent study empirically investigates to identify the linkages between stock market development, key macro-economic factors and institutional factors in the BRICS economies. The study covers the time period from 2000 to 2017. The dependent variable is the country's stock market development and the independent variables consist of six macroeconomic variables and five institutional variables. The study employs a panel cointegration test, Fully Modified OLS (FMOLS), a Pooled Mean Group (PMG) approach and a heterogeneous panel non-causality test.The findings of the study indicate co-integration among the selected variables across the BRICS stock markets. Long-run estimations reveal that five macroeconomic variables and four variables related to institutional quality are positive and statistically significant. Further, short-run causalities between stock market capitalization and selected variables are detected through the test of non-causality in a heterogeneous panel setting. The findings suggest that policymakers in the BRICS countries should enhance robust macroeconomic conditions to support their financial markets and should strengthen the institutional quality drivers to stimulate the pace of stock market development in their countries.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.6
• /
• pp.732-736
• /
• 2020

Theobroma cacao L., a fruit of cacao trees, is a perennial plant, which belongs to Sterculiaceae, and is native to the Amazon in South Africa. It also has been known for its various biologically active effects, such as anti-oxidation, anti-cancer, and anti-bacterial. The spleen cell proliferations of mice were measured at 48 hours after treatment of Theobroma cacao L. water extracts in seven concentrations(0, 5, 10, 50, 100, 250, 500 and 1,000 ㎍/mL) an ELISA assay. The production of cytokine (IL-1β, TNF-α, IFN-γ), is secreted by macrophages stimulated with LPS, was detected by ELISA assay using the cytokine kit. From the results of in vitro study, both splenocytes and cytokine production activated by peritoneal macrophages have increased when water extracts were supplemented in the range between 250 and 500 ㎍/mL concentration. Notably, splenocytes production has a signigicant proliferation at 500 ㎍/mL concentration. The result from this research suggests that supplementation with Theobroma cacao L. water extracts may enhance the immune function by stimulating the splenocyte proliferation and improving the cytokine production activating macrophage in vitro.

• International Journal of Computer Science & Network Security
• /
• v.22 no.7
• /
• pp.131-146
• /
• 2022

The Internet is becoming a basic need for many individuals globally in this digital age. The youths became more active online than before, with the majority relying on different platforms to communicate and interact with peers. Saudi Arabia is one of the nations where internet usage is high, with an increasing number of active internet users. The youth in Saudi Arabia are engaged in various online platforms. However, they lack adequate knowledge about cybersecurity and the dangers of internet usage, which exposes them to the risk of falling victims to cybercriminals. The most common dangers of internet usage include viruses, malware, phishing, and hacking, compromising users' sensitive information. Increased awareness of these potential threats helps protect Internet users and secure their data. The understanding of the dangers of Internet usage among youths varies across countries. In this regard, our study explores the risks of internet usage among youth in Saudi Arabia compared to the United States, South Africa, and New Zealand.