• Title/Summary/Keyword: South Africa

Search Result 282, Processing Time 0.027 seconds

Borehole Disposal Concept: A Proposed Option for Disposal of Spent Sealed Radioactive Sources in Tanzania (보어홀 처분 개념: 탄자니아의 폐밀봉선원 처분을 위한 제안)

  • Salehe, Mikidadi;Kim, Chang-Lak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.11 no.4
    • /
    • pp.293-301
    • /
    • 2013
  • Borehole Disposal Concept (BDC) was initiated by the South African Nuclear Energy Corporation (NECSA) with the view to improve the radioactive waste management practices in Africa. At a time when geological disposal of radioactive waste is being considered, the need to protect ground water from possible radioactive contamination and the investigation of radionuclides migration through soil and rocks of zone of aeration into ground water has becomes very imperative. This is why the Borehole Disposal Concept (BDC) is being suggested to address the problem. The concept involves the conditioning and emplacement of disused sealed radioactive sources in an engineered facility of a relatively narrow diameter borehole (260 mm). Tanzania is operating a Radioactive Waste Management Facility where a number of spent sealed radioactive sources with long and short half lives are stored. The activity of spent sealed radioactive sources range from (1E-6 to 8.8E+3 Ci). However, the long term disposal solution is still a problem. This study therefore proposing the country to adopt the BDC, since the repository requires limited land area and has a low probability of human intrusion due to the small footprint of the borehole.

A Scrutiny of the Essence of Business Incubators in the Distribution Sector

  • ERESIA-EKE, Chukuakadibia;IWU, Chux Gervase;JAIYEOLA, Afeez Olalekan;MUSIKAVANHU, Tichaona Buzy
    • Journal of Distribution Science
    • /
    • v.17 no.6
    • /
    • pp.5-13
    • /
    • 2019
  • Purpose - The potential for small businesses in the distribution sector to contribute to socio-economic development remains largely inert due to a litany of challenges that they face. Incubators have emerged as the 'silver bullet' for most of the problems but the extent to which they are effectively helping small business overcome their challenges remains debatable. This study seeks to determine the core reasons why respondents enrolled in an incubator, the essence of the incubator and the extent to which the incubator performance is satisfactory. Research design, data, and methodology - A positivist philosophical approach was adopted for the study. This quantitative study used a survey method to collect data from incubatees in a cross-sectional manner. The data were subsequently analysed to generate necessary insights. Results - Results reveal that the gender composition of incubatees is severely skewed in favour of males. Also, most incubatees enrolled in the incubators with a hope that it would ease their pathway to big businesses, financiers and business registration institutions, and it is not. Conclusion - Incubators are mostly inward-looking and are adept at offering training interventions. To improve the effectiveness of incubators, it is necessary to invest efforts in attracting more females and building networks with key external stakeholders that could possibly assist the incubatees establish and grow their businesses.

Centella asiatica extract prevents visual impairment by promoting the production of rhodopsin in the retina

  • Park, Dae Won;Jeon, Hyelin;So, Rina;Kang, Se Chan
    • Nutrition Research and Practice
    • /
    • v.14 no.3
    • /
    • pp.203-217
    • /
    • 2020
  • BACKGROUND/OBJECTIVE: Centella asiatica, also known as Gotu kola, is a tropical medicinal plant native to Madagascar, Southeast Asia, and South Africa. It is well known to have biological activities, including wound healing, anti-inflammatory, antidiabetic, cytotoxic, and antioxidant effects. The purpose of this study was to determine the efficacy of extracts of C. asiatica against age-related eye degeneration and to examine their physiological activities. MATERIALS/METHODS: To determine the effects of CA-HE50 (C. asiatica 50% EtOH extract) on retinal pigment cells, we assessed the cytotoxicity of CoCl2 and oxidized-A2E in ARPE-19 cells and observed the protective effects of CA-HE50 against N-methyl-N-nitrosourea (MNU)-induced retinal damage in C57BL/6 mice. In particular, we measured factors related to apoptosis and anti-oxidation and the protein levels of rhodopsin/opsin. We also measured glucose uptake to characterize glucose metabolism, a major factor in cell protection. RESULTS: Induction of cytotoxicity with CoCl2 and oxidized-A2E inhibited decreases in the viability of ARPE-19 cells when CA-HE50 was administered, and promoted glucose uptake under normal conditions (P < 0.05). In addition, CA-HE50 inhibited degeneration/apoptosis of the retina in the context of MNU-induced toxicity (P < 0.05). In particular, CA-HE50 at 200 mg/kg inhibited the cleavage of pro-caspase-3 and pro-poly (ADP-ribose)-polymerase and maintained the expressions of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 similar to normal control levels. Rhodopsin/opsin expression was maintained at a higher level than in normal controls. CONCLUSION: A series of experiments confirmed that CA-HE50 was effective for inhibiting or preventing age-related eye damage/degeneration. Based on these results, we believe it is worthwhile to develop drugs or functional foods related to age-related eye degeneration using CA-HE50.

Atmospheric Acidic Deposition: State of Acid Rain in Korea and the World (대기산성강하물: 한국과 세계의 산성비 실태)

  • Kim, Joon-Ho
    • The Korean Journal of Ecology
    • /
    • v.28 no.3
    • /
    • pp.169-180
    • /
    • 2005
  • Nitrogen dioxide concentration was being grown ca. 8% per year although sulphur dioxide concentration was being reduced ca. 10% per year in Seoul from 1996 to 2003. The rainwater was heavily acidic with pH 4.19 to 4.68 in Seoul during 1980 to 1991. Acidity score on the basis of the total anion concentration of rainwater follows the higher in sequence with Seoul(Kwanaksan)(341.5 ${\mu}equiv{\cdot}L^{-1}$), Gwangneung(199.2 ${\mu}equiv{\cdot}L^{-1}$) and whole Korea mean(10.3 ${\mu}equiv{\cdot}L^{-1}$). Rainwaters from 38 sampling sites of 16 countries in the world, on the basis of the acidity score, are classified and designated as five acid rain grades(ARG): the least score is founded in Tana Rata(16.2 ${\mu}equiv{\cdot}L^{-1}$), Malaysia where has the best rain but the greatest founded in Chongquing(541.1 ${\mu}equiv{\cdot}L^{-1}$), China where has the worst rain in the world. Even though acidic deposition decrease with time in the world generally, it is expected to increase in Asia, Africa and Mid-South America.

A Study on Spillover of Technology Trade against Post- BRICs (BRICs 이후 신흥국과의 기술무역 확산방안 연구)

  • Baek, Eun-Young
    • International Commerce and Information Review
    • /
    • v.16 no.5
    • /
    • pp.361-385
    • /
    • 2014
  • This study focused on Spillover of Technology Trade against Post- BRICs of the Technology export of Korea. Therefore this study made an empirical analysis for investigating the competitiveness of technology export in Korea and using panel data 2003-2012 of technology trade data between 6 Countries(Indonesia, Mexico, Nigeria, South Africa, Turkey, Vietnam). In particular, the study deduced the correlation between technology export in Korea using the variables of Gross Domestic Expenditure on R&D and Per capita GDP, distance, population, free-trade index, FDI, Technology-Intensive Manufactures, Pattern Investment fixed effect model in panel linear regression model. It is found that the Technology export of Korea SMEs made a significant effect on the pop, free_trade, and distance. and also it is found that the Technology export of Korea Big Business made a significant effect on the per-GDP, Fdi from Korea, free_trade, and distance. The results suggest that the study should use technology gap variables and the strategy for activating the Technology export of Korea should be made for future works.

  • PDF

The KMTNet View of Variable Stars : Pulsation and Rotation of the EL CVn-type Eclipsing Binary J0247-25

  • Kim, Seung-Lee;Lee, Jae Woo;Lee, Chung-Uk;Lee, Yongseok;Lee, Dong-Joo;Hong, Kyeongsoo;Cha, Sang-Mok;Kim, Dong-Jin;Park, Byeong-Gon
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.43 no.1
    • /
    • pp.41.2-41.2
    • /
    • 2018
  • EL CVn-type eclipsing binaries are composed of a massive A-type main-sequence primary star and a hotter B-type secondary one. These are worthy of particular attention because the secondary stars are rare objects to be extremely low-mass white dwarf precursors (ELM proto-WD) with the mass of ${\leq}0.2M_{\odot}$, evolving to higher effective temperatures and higher surface gravities. A few of them were discovered to show multi-periodic pulsations in one or both components. We monitored one of these rare and interesting objects, J0247-25 (=1SWASP J024743.37-251549.2), at two KMTNet sites of SAAO in South Africa and SSO in Australia. The observations were performed with the KMTNet 1.6m telescopes and pre-science 4K CCD cameras during the system test run from July to November 2014. Using the photometric data obtained for a total of 23 nights, we constructed well-defined eclipsing light curves in B/V-bands and derived absolute parameters (mass and radius, etc.) of each binary component. After subtracting model eclipsing curves from the data, we detected seven frequencies with 33~53 cycles per day (c/d) and identified them to be Delta Sct-type pulsations originated from the A-type primary component. Five frequencies were turned out to be excited by rotational splitting of non-radial pressure modes, enabled us to investigate rotational properties. We could not detect any frequency higher than 100 c/d, implying that pulsation amplitudes of the proto-WD secondary decrease greatly.

  • PDF

Comparing Plant Species Diversity of Mountainous Deserts - Successes and Pitfalls

  • Van Etten, Eddie J.B.
    • The Korean Journal of Ecology
    • /
    • v.27 no.2
    • /
    • pp.79-86
    • /
    • 2004
  • An extensive study of the vegetation characteristics of the Hamersley Ranges, a mountainous desert area of north-west Australia, facilitated the comparison of plant species diversity measures with mountainous deserts of other parts of the world. Alpha diversity was defined as the number of species co-existing at local scales and was found to average 18 species per 0.1 ha for the Hamersley Ranges. This was found to be similar to seven other mountainous deserts in North and South America, and southern Africa. Variation in alpha diversity between these deserts was found to considerably lower than within deserts, suggesting that local processes control species richness at local scales. Beta diversity, defined here as turnover in species composition at various spatial scales, can be measured in many ways. For the Hamersley Ranges, Wilson's β ranged from 1.2 to 1.6 for five sites along a topographic gradient, whereas Whittaker's β between different plant communities was found to average 0.93. Comparable data was not found for other desert areas, but comparisons to non-desert areas suggest beta diversity within landscapes is relatively high and is likely to reflect the considerable landform heterogeneity of the Hamersley Ranges. 55∼70% of species were shared between different landscapes of the Hamersley Ranges; comparisons to other regions suggest beta diversity at this scale is relatively low. Gamma diversity, the number of species over large spatial extents, was successfully compared using regression analysis of the log-log species - area relationship. This revealed that the northern Sonoran desert has significantly less species than the Nama (inland) Karoo and Hamersley Ranges over medium spatial extents, but species numbers were similar at a regional scale. Several constraints to the valid comparison of species diversity were identified, including lack of standardisation of sampling techniques, the wide range of measures employed, general lack of published data, and the influence of the various components of spatial scale on most diversity measures. Recommendations on how to improve future comparative work are provided.

North Korea's sudden change scenario 2 : Focusing on the cases of Jasmine revolution countries (북한의 급변사태 시나리오 2 : 재스민혁명 국가들의 사례분석을 중심으로)

  • Lee, Dae Sung
    • Convergence Security Journal
    • /
    • v.17 no.4
    • /
    • pp.47-52
    • /
    • 2017
  • The wave of democratization that started in southern Europe spread to South America and Asia, dismantling the Soviet Union and Eastern European countries and appeared as a Jasmine revolution in countries of North Africa and the Middle East. As a result, many scholars have actively carried out researches related to the sudden change of North Korea, while taking a cautious view that the Jasmine Revolution might occur in North Korea. The focuses of the studies were on the cause and timing of the sudden change and the main forces of the revolution in North Korea. There weren't enough discussions on how the process will be developed and whether there will be a system change. In this study, based on the results of analyzing the systematic changes of the Jasmine revolution nations, it suggested five scenarios that can be developed after the sudden change of North Korea. Scenario type I: Relatively peaceful and the possibility of regime change, Scenario type II: Reunification and then civil war, Scenario type III: Regime changed but one of Kim Il Sung family grabbing the power, Scenario type IV: Successful regime change but civil war happening, Scenario type V: Regime change failed and civil war continuing.

Post-national Trends in 21st Century Fashion Based on Multiculturalism (다문화주의를 수용한 21세기 패션의 탈 민족적 경향)

  • Kim, Sun-Young
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.34 no.9
    • /
    • pp.1429-1441
    • /
    • 2010
  • This study examines the post-national trends of the $21^{st}$ century fashion that has embraced multiculturalism. This study conducted a literature view to explore the concept of multiculturalism and the background of post-national phenomena appearing in contemporary fashion. In addition, as a case study, the author used local and foreign fashion magazines and collections published between 2000 and 2009, in addition to other related materials available on the Internet. The objective was to analyze photographic materials in which post-national features are reflected. From this study, the post-national trends in $21^{st}$ century fashion that adopted multiculturalism are as follows: The first is that oriental culture is more actively embraced. In the past, the tendency of embracing the oriental culture was mainly developed with a focus on China and Japan, but recently the tendency has spread to Southeast Asian countries and national/ethnic minorities that include Mongolians and Tibetans that is present in more active ways that reflect oriental sentiment and philosophy as well as adopts simple images. Second, $21^{st}$ century fashion based on multiculturalism broadens the interest in the understanding of nations in the regions of Africa, Middle East, and South America and uses regional folk costumes or indigenous characteristics to create new things instead of staying within a fixed paradigm. Third, as horizontal transfer is involved in ways of looking at culture, $21^{st}$ century fashion shows a post-national tendency to use regional cultures and folk costumes of the occidental world that includes North and West Europe in addition to non-mainstream regions (as considered so far). Fourth, dress elements of many heterogeneous national cultures are combined to create multinational images difficult to define in terms of a specific national culture or clothing style.

Co-occurrence Patterns of Bird Species in the World

  • Kim, Young Min;Hong, Sungwon;Lee, Yu Seong;Oh, Ki Cheol;Kim, Gu Yeon;Joo, Gea-Jae
    • Korean Journal of Ecology and Environment
    • /
    • v.50 no.4
    • /
    • pp.478-482
    • /
    • 2017
  • In order to identify key nations and bird species of conservation concern we described multinational collaborations as defined using network analysis linked by birds that are found in all nations in the network. We used network analysis to assess the patterns in bird occurrence for 10,422 bird inventories from 244 countries and territories. Nations that are important in multinational collaborations for bird conservation were assessed using the centrality measures, closeness and betweenness centrality. Countries important for the multinational collaboration of bird conservation were examined based on their centrality measures, which included closeness and betweenness centralities. Comparatively, the co-occurrence network was divided into four groups that reveal different biogeographical structures. A group with higher closeness centrality included countries in southern Africa and had the potential to affect species in many other countries. Birds in countries in Asia, Australia and the South Pacific that are important to the cohesiveness of the global network had a higher score of betweenness centrality. Countries that had higher numbers of bird species and more extensively distributed bird species had higher centrality scores; in these countries, birds may act as excellent indicators of trends in the co-occurrence bird network. For effective bird conservation in the world, much stronger coordination among countries is required. Bird co-occurrence patterns can provide a suitable and powerful framework for understanding the complexity of co-occurrence patterns and consequences for multinational collaborations on bird conservation.