• Title/Summary/Keyword: two communities

Search Result 965, Processing Time 0.025 seconds

Anonymous Participation and Collaboration Efficiency in Online Communities

  • Hong Joo Lee;Jong Woo Kim;Hyun Jung Park;Sung Joo Park
    • Asia pacific journal of information systems
    • /
    • v.30 no.3
    • /
    • pp.497-512
    • /
    • 2020
  • Anonymity is one of the key factors that influence communication and the work behaviours of people. It is even more evident in an online community where the role of anonymity can be akin to a double-edged sword: it can increase participation while at the same time having detrimental effects due to irresponsible and disruptive behaviour. Most studies on anonymous participation in groups or communities have reported this ambivalent view of anonymity: positive or negative. Furthermore, the effects of anonymous participation may be different in a dynamic sense because the task characteristics of participation can vary across time. In this study, we hypothesise that the effects of anonymity in online collaboration differ across the stages of collaboration. We analysed 2,978 featured articles on the English-language Wikipedia website and investigated the contributions of anonymous participants. While the contributions of anonymous participants were negative to collaboration efficiency as a whole, the negative effect of anonymous participants was stronger in the earlier stage than the later stage of collaboration. These findings indicate that the effect of anonymity has two sides in terms of collaboration efficiency in the same collaborative environment.

An Analysis of Vegetation-Environment Relationships of Quercus mongolica Communities by TWINSPAN and DCCA (TWINSPAN과 DCCA에 의한 신갈나무군집(群集)과 환경(環境)의 상관관계(相關關係) 분석(分析))

  • Song, Ho Kyung;Jang, Kyu Kwan;Kim, Seong Deog
    • Journal of Korean Society of Forest Science
    • /
    • v.84 no.3
    • /
    • pp.299-305
    • /
    • 1995
  • Vegetational data from 81 quadrats of Quercus mongolica communities in Mt. Odae and Mt. Jumbong were analysed by applying two multivariate methods : two - way indicator species analysis(TWNSPAN) for classification and detrended canonical correspondence analysis(DCCA) for ordination. The dominant tree species of Quercus mongolica communities were found in the order of Quercus mongolica, Acer pseudosieboldianum. Tilia amurensis, Carpinus cordata, Acer mono, and Fraxinus rhynchophylla. The forest vegetation of Quercus mongolica community was classified into Quercus mongolica, Quercus mongolica - Carpinus cordata, and Quercus mongolica - Abies nephrolepis groups according to the TWNSPAN. The relationships between the distribution of dominant groups for forest vegetation and soil condition in Quercus mongolica communities were investigated by analysing elevation and soil nutrition gradients. Quercus mongolica group was distributed in the low elevation and poor nutrition area of total nitrogen, Quercus mongolica - Carpinus cordata group was distributed in the low elevation and good nutrition area of $Mg^{{+}{+}}$ and $Ca^{{+}{+}}$, while Quercus mongolica Abies nephrolepis group was distributed in the high elevation and poor nutrition area of $Mg^{{+}{+}}$ and $Ca^{{+}{+}}$. The two dominant factors influencing community distribution were elevation and total nitrogen.

  • PDF

Community Distribution on Mountain Forest Vegetation of the Birobong Area in the Odaesan National Park, Korea (오대산 국립공원 비로봉 일대 산지 삼림식생의 군락분포에 관한 연구)

  • Choi, Young-Eun;Kim, Chang-Hwan;Oh, Jang-Geun;Lee, Nam-Sook
    • Korean Journal of Ecology and Environment
    • /
    • v.47 no.2
    • /
    • pp.91-102
    • /
    • 2014
  • Forest vegetation of Birobong (1,563 m) in Odaesan National Park is classified into mountain forest vegetation and flatland forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, valley forest, coniferous forest, subalpine coniferous forest, subalpine broad-leaved forest, afforestation and etc., while riparian forest was found under the category of flatland forest vegetation. Including 196 communities of mountain forest vegetation, 1 community of flatland forest vegetation and 4 communities of other vegetation, the total of 201 communities were researched; the distributed colonies classified by physiognomy classification are 62 communities deciduous broad-leaved forest, 84 communities of valley forest, 15 communities of coniferous forests, 16 communities of subalpine coniferous forest, 3 communities of subalpine broad-leaved forest, 16 afforestation, 1 community of flatland forest and 4 other communities. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus variabilis, Tilia amurensis communities account for 37.08 percent of deciduous broad-leaved forest, Juglans mandshurica, Fraxinus mandshurica, Cornus controversa, Populus koreana community takes up 1.59 percent of mountain valley forest, Pinus densiflora community holds 6.65 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Quercus variabilis, Tilia amurensis, Juglans mandshurica, Fraxinus mandshurica, Cornus controversa, Populus koreana, Pinus densiflora are distributed as dominant species of the uppermost part in a forest vegetation of Birobong in Odaesan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Tilia amurensis and Juglans mandshurica which are climax species in the area. However, the distribution rate of deciduous broad-leaved forest seems to increase gradually due to global warming and artificial disturbance.

Knowledge and Awareness of Human Papillomavirus (HPV), Cervical Cancer and HPV Vaccine among Women in Two Distinct Nepali Communities

  • Johnson, Derek Christopher;Bhatta, Madhav Prasad;Gurung, Santosh;Aryal, Shilu;Lhaki, Pema;Shrestha, Sadeep
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.15 no.19
    • /
    • pp.8287-8293
    • /
    • 2014
  • Background: This study assessed human papillomavirus (HPV), cervical cancer, and HPV vaccine knowledge and awareness among women in two sub-populations in Nepal - Khokana, a traditional Newari village in the Lalitpur District about eight kilometers south of Kathmandu, and Sanphebagar, a village development committee within Achham District in rural Far-Western Nepal. Methods: Study participants were recruited during health camps conducted by Nepal Fertility Care Center, a Nepali non-governmental organization. Experienced staff administered a Nepali language survey instrument that included questions on socio-demographics, reproductive health and knowledge on HPV, cervical cancer, and the HPV vaccine. Results: Of the 749 participants, 387 (51.7%) were from Khokana and 362 (48.3%) were from Sanphebagar. Overall, 53.3% (n=372) of women were aware of cervical cancer with a significant difference between Khokana and Sanphebagar (63.3% vs 43.0%; p=0.001). Overall, 15.4% (n=107) of women had heard of HPV and 32% (n=34) of these women reported having heard of the HPV vaccine. If freely available, 77.5% of the women reported willingness to have their children vaccinated against HPV. Factors associated with cervical cancer awareness included knowledge of HPV (Khokana: Odds Ratio (OR)=24.5; (95% Confidence Interval (CI): 3.1-190.2, Sanphebagar: OR=14.8; 95% CI: 3.7-58.4)) and sexually transmitted infections (Khokana: OR=6.18; 95% CI: 3.1-12.4; Sanphebagar: OR=17.0; 95% CI: 7.3-39.7) among other risk factors. Conclusions: Knowledge and awareness of HPV, cervical cancer, and the HPV vaccine remains low among women in Khokana and Sanphebagar. Acceptance of a freely available HPV vaccine for children was high, indicating potentially high uptake rates in these communities.

Duration-Related Variations in Archaeal Communities after a Change from Upland Fields to Paddy Fields

  • Jiang, Nan;Wei, Kai;Chen, Lijun;Chen, Rui
    • Journal of Microbiology and Biotechnology
    • /
    • v.26 no.5
    • /
    • pp.867-875
    • /
    • 2016
  • Archaea substantially contribute to global geochemical cycling and energy cycling and are impacted by land-use change. However, the response of archaeal communities to a change from upland field to paddy field has been poorly characterized. Here, soil samples were collected at two depths (0-20 cm and 20-40 cm) from one upland field and six paddy fields that were established on former upland fields at different times (1, 5, 10, 20, 30, and 40 years before the study). Barcoded pyrosequencing was employed to assess the archaeal communities from the samples at taxonomic resolutions from phylum to genus levels. The total archaeal operational taxonomic unit (OTU) richness showed a significant positive correlation with the land-use change duration. Two phyla, Euryarchaeota and Crenarchaeota, were recorded throughout the study. Both the relative abundance and OTU richness of Euryarchaeota increased at both depths but increased more steadily at the subsurface rather than at the surface. However, these data of Crenarchaeota were the opposite. Additionally, the archaeal composition exhibited a significant relationship with C/N ratios, total phosphorus, soil pH, Olsen phosphorus, and the land-use change duration at several taxonomic resolutions. Our results emphasize that after a change from upland fields to paddy fields, the archaeal diversity and composition changed, and the duration is an important factor in addition to the soil chemical properties.

Analysis of Microbial Communities in Biofilms from CSTR-Type Hollow Fiber Membrane Biofilm Reactors for Autotrophic Nitrification and Hydrogenotrophic Denitrification

  • Shin, Jung-Hun;Kim, Byung-Chun;Choi, Okkyoung;Kim, Hyunook;Sang, Byoung-In
    • Journal of Microbiology and Biotechnology
    • /
    • v.25 no.10
    • /
    • pp.1670-1679
    • /
    • 2015
  • Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH4+-N/m3/d and 0.10-0.21 kg NO3--N/m3/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH4+ or NO3- loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs.

Biomethanation of Sewage Sludge with Food Waste Leachate Via Co-Digestion

  • Shin, Jingyeong;Kim, Young Beom;Jeon, Jong Hun;Choi, Sangki;Park, In Kyu;Kim, Young Mo
    • Journal of Microbiology and Biotechnology
    • /
    • v.27 no.8
    • /
    • pp.1513-1518
    • /
    • 2017
  • Anaerobic mono- and co-digestion of sewage sludge and food waste leachate (FWL) were performed by assessing methane production and characterizing microbial communities. Anaerobic digestion (AD) of waste activated sludge (WAS) alone produced the lowest methane ($281ml\;CH_4$), but an approximately 80% increase in methane production was achieved via co-digestion of WAS and FWL ($506ml\;CH_4$). There were less differences in the diversity of bacterial communities in anaerobic digesters, while archaeal (ARC) and bacterial (BAC) amounts reflected AD performance. Compared with the total ARC and BAC amounts in the mono-digestion of WAS, the ARC and BAC amounts increased two and three times, respectively, during co-digestion of FWL and WAS. In characterized archaeal communities, the dominant ratio of hydrogenotrophic methanogens in the mono-digestion of WAS approached nearly a 1:1 ratio of the two acetoclastic and hydrogenotrophic methanogens in the co-digestion of FWL and WAS. The ARC/BAC ratio in the digesters varied in the range of 5.9% to 9.1%, indicating a positive correlation with the methane production of AD.

Developing Teachers' Professionalism -Focusing on Korean Cases- (교사 전문성 향상 방안 연구 -한국의 학습 커뮤니티 사례-)

  • Na, Hyeok-Jin
    • Industry Promotion Research
    • /
    • v.5 no.1
    • /
    • pp.53-62
    • /
    • 2020
  • This study reviewed the structural and operational systems of two professional learning communities in Korean society and analyzed their strengths and weaknesses: the Association of Korean History Teachers and the Communities of Elementary School Classroom Management. In order to analyze these cases, Robey's organizational change model was used as a theoretical frame. Two research methods were mainly employed for this study: literature review and on-site interviews. The analysis found several strengths (easy accessibility, led by teachers' initiative and autonomous will, abundant and practical teaching solutions) and weaknesses (financial burden, lack of theoretical background, sporadic participants). In conclusion, this study suggests three strategies for an educational leader who has an important role in developing a teacher's professionalism: 1) Make an institutional effort to stimulate teachers' motivation to learn, 2) Create a strong network of university professors and other experts for career advice, 3) Build a synthesized and consolidated system.

Investigation of Bacterial Diversity in Membrane Bioreactor and Conventional Activated Sludge Processes from Petroleum Refineries Using Phylogenetic and Statistical Approaches

  • Silva, Cynthia;Jesus, Ederson C.;Torres, Ana P. R.;Sousa, Maira P.;Santiago, Vania M. J.;Oliveira, Valeria M.
    • Journal of Microbiology and Biotechnology
    • /
    • v.20 no.3
    • /
    • pp.447-459
    • /
    • 2010
  • Bacterial diversity of two distinct wastewater treatment systems, conventional activated sludge (CAS) and membrane bioreactor (MBR), of petroleum refineries were investigated through 16S rRNA gene libraries. Sequencing and phylogenetic analysis showed that the bacterial community composition of sludge samples was distinct between the two wastewater treatment systems. MBR clones belonged predominantly to Class Betaproteobacteria, represented mainly by genera Thiobacillus and Thauera, whereas CAS clones were mostly related to Class Alphaproteobacteria, represented by uncultured bacteria related to Order Parvularculales. Richness estimators ACE and Chao revealed that the diversity observed in both libraries at the species level is an underestimate of the total bacterial diversity present in the environment and further sampling would yield an increased observed diversity. Shannon and Simpson diversity indices were different between the libraries and revealed greater bacterial diversity for the MBR library, considering an evolutionary distance of 0.03. LIBSHUFF analyses revealed that MBR and CAS communities were significantly different at the 95% confidence level ($P{\leq}0.05$) for distances $0{\leq}D{\leq}0.20$. This work described, qualitatively and quantitatively, the structure of bacterial communities in industrial-scale MBR and CAS processes of the wastewater treatment system from petroleum refineries and demonstrated clearly differentiated communities responsible for the stable performance of wastewater treatment plants.

Analysis of Microbial Communities Using Culture-dependent and Culture-independent Approaches in an Anaerobic/Aerobic SBR Reactor

  • Lu Shipeng;Park Min-Jeong;Ro Hyeon-Su;Lee Dae-Sung;Park Woo-Jun;Jeon Che-Ok
    • Journal of Microbiology
    • /
    • v.44 no.2
    • /
    • pp.155-161
    • /
    • 2006
  • Comparative analysis of microbial communities in a sequencing batch reactor which performed enhanced biological phosphorus removal (EBPR) was carried out using a cultivation-based technique and 16S rRNA gene clone libraries. A standard PCR protocol and a modified PCR protocol with low PCR cycle was applied to the two clone libraries of the 16S rRNA gene sequences obtained from EBPR sludge, respectively, and the resulting 424 clones were analyzed using restriction fragment length polymorphisms (RFLPs) on 16S rRNA gene inserts. Comparison of two clone libraries showed that the modified PCR protocol decreased the incidence of distinct fragment patterns from about 63 % (137 of 217) in the standard PCR method to about 34 % (70 of 207) under the modified protocol, suggesting that just a low level of PCR cycling (5 cycles after 15 cycles) can significantly reduce the formation of chimeric DNA in the final PCR products. Phylogenetic analysis of 81 groups with distinct RFLP patterns that were obtained using the modified PCR method revealed that the clones were affiliated with at least 11 phyla or classes of the domain Bacteria. However, the analyses of 327 colonies, which were grouped into just 41 distinct types by RFLP analysis, showed that they could be classified into five major bacterial lineages: ${\alpha},\;{\beta},\;{\gamma}-$ Proteobacteria, Actinobacteria, and the phylum Bacteroidetes, which indicated that the microbial community yielded from the cultivation-based method was still much simpler than that yielded from the PCR-based molecular method. In this study, the discrepancy observed between the communities obtained from PCR-based and cultivation-based methods seems to result from low culturabilities of bacteria or PCR bias even though modified culture and PCR methods were used. Therefore, continuous development of PCR protocol and cultivation techniques is needed to reduce this discrepancy.