49 research outputs found

    MMOG Game-Based Collaborative Learning: An Exploratory Study and its Research Potential

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    This study aims to theoretically explore whether Massively Multiplayer Online Game (MMOG) is an effective collaborative learning environment, empirically examine the occurrence of knowledge creation in MMOG game-play, and conceptually advocate the research potential of MMOG game-based collaborative learning. Although a growing number of researchers have started to use MMOG as a new generation of educational platform, the study of the theoretical justification for the occurrence of collaborative learning behavior in MMOG are still under-researched. To bridge this gap, this study integrates MMOG and technology-based collaborative learning streams of research to theoretically explore whether MMOG is an effective learning platform based on Alavi’s three attributes of effective technology-mediated collaborative learning environment. In order to examine the occurrence of knowledge creation in the MMOG game-based collaborative learning, we propose definitions of explicit and tacit knowledge in MMOG. Then we conduct an exploratory study using a semi-structural interview approach to collect qualitative data, in order to support our stipulation of the occurrence of four modes of knowledge conversion in MMOG game-play based on the Nonaka’s dynamic theory of organization creation. According to our research findings, this paper advocates research potential of MMOG game-based collaborative learning in future research

    Service scenarios - A socio-technical approach to business service modeling

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    Massively Multiplayer Online Game (MMOG) is a unique categorization of electronic game which allows thousands of players to play simultaneously through the Internet in the same virtual environment. A number of researchers have started to introduce the use of MMOG as a new generation of educational platform, allowing players to interact and to learn together through collaborative game-play. However, the answers for the occurrence of collaborative learning behaviour and the motivational drivers for learning collaboratively in a MMOG are still underresearched. Motivated by such concerns, this study tests a theoretical model to explain individual’s intention to learn by peer motivations. The model employs motivational theories to propose two external motivational factors, namely peer intrinsic motivation and peer extrinsic motivation, and investigates effects of the two new constructs on MMOG players’ intention to learn individually and intention to learn collaboratively by building on the cognitive learning theory. Based on a study with 94 valid current MMOG player responses, PLS analysis shows that peer intrinsic motivation to play has a significant positive influence on the intention to learn collaboratively, while peer extrinsic motivation to play has a significant positive influence on the intention to learn individually. The results of our findings indicate potential implications to researchers, educators and game developers

    Human TRIM Gene Expression in Response to Interferons

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    Tripartite motif (TRIM) proteins constitute a family of proteins that share a conserved tripartite architecture. The recent discovery of the anti-HIV activity of TRIM5α in primate cells has stimulated much interest in the potential role of TRIM proteins in antiviral activities and innate immunity.To test if TRIM genes are up-regulated during antiviral immune responses, we performed a systematic analysis of TRIM gene expression in human primary lymphocytes and monocyte-derived macrophages in response to interferons (IFNs, type I and II) or following FcγR-mediated activation of macrophages. We found that 27 of the 72 human TRIM genes are sensitive to IFN. Our analysis identifies 9 additional TRIM genes that are up-regulated by IFNs, among which only 3 have previously been found to display an antiviral activity. Also, we found 2 TRIM proteins, TRIM9 and 54, to be specifically up-regulated in FcγR-activated macrophages.Our results present the first comprehensive TRIM gene expression analysis in primary human immune cells, and suggest the involvement of additional TRIM proteins in regulating host antiviral activities

    Emergence and phylodynamics of Citrus tristeza virus in Sicily, Italy

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    [EN] Citrus tristeza virus (CTV) outbreaks were detected in Sicily island, Italy for the first time in 2002. To gain insight into the evolutionary forces driving the emergence and phylogeography of these CTV populations, we determined and analyzed the nucleotide sequences of the p20 gene from 108 CTV isolates collected from 2002 to 2009. Bayesian phylogenetic analysis revealed that mild and severe CTV isolates belonging to five different clades (lineages) were introduced in Sicily in 2002. Phylogeographic analysis showed that four lineages co-circulated in the main citrus growing area located in Eastern Sicily. However, only one lineage (composed of mild isolates) spread to distant areas of Sicily and was detected after 2007. No correlation was found between genetic variation and citrus host, indicating that citrus cultivars did not exert differential selective pressures on the virus. The genetic variation of CTV was not structured according to geographical location or sampling time, likely due to the multiple introduction events and a complex migration pattern with intense co- and recirculation of different lineages in the same area. The phylogenetic structure, statistical tests of neutrality and comparison of synonymous and nonsynonymous substitution rates suggest that weak negative selection and genetic drift following a rapid expansion may be the main causes of the CTV variability observed today in Sicily. Nonetheless, three adjacent amino acids at the p20 N-terminal region were found to be under positive selection, likely resulting from adaptation events.A.W. and S.F.E. were supported by grant BFU2012-30805 from the Spanish Secretaria de Estado de Investigacion, Desarrollo e Innovacion and by a grant 22371 from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Davino, S.; Willemsen, A.; Panno. Stefano; Davino, M.; Catara, A.; Elena Fito, SF.; Rubio, L. (2013). Emergence and phylodynamics of Citrus tristeza virus in Sicily, Italy. PLoS ONE. 8:66700-66700. doi:10.1371/journal.pone.0066700S66700667008Domingo, E., & Holland, J. J. (1997). RNA VIRUS MUTATIONS AND FITNESS FOR SURVIVAL. Annual Review of Microbiology, 51(1), 151-178. doi:10.1146/annurev.micro.51.1.151Grenfell, B. T. (2004). Unifying the Epidemiological and Evolutionary Dynamics of Pathogens. Science, 303(5656), 327-332. doi:10.1126/science.1090727Moya, A., Holmes, E. C., & González-Candelas, F. (2004). The population genetics and evolutionary epidemiology of RNA viruses. Nature Reviews Microbiology, 2(4), 279-288. doi:10.1038/nrmicro863Gray, R. R., Tatem, A. J., Lamers, S., Hou, W., Laeyendecker, O., Serwadda, D., … Salemi, M. (2009). Spatial phylodynamics of HIV-1 epidemic emergence in east Africa. AIDS, 23(14), F9-F17. doi:10.1097/qad.0b013e32832faf61Holmes, E. C. (2008). Evolutionary History and Phylogeography of Human Viruses. Annual Review of Microbiology, 62(1), 307-328. doi:10.1146/annurev.micro.62.081307.162912Pybus, O. G., Suchard, M. A., Lemey, P., Bernardin, F. J., Rambaut, A., Crawford, F. W., … Delwart, E. L. (2012). Unifying the spatial epidemiology and molecular evolution of emerging epidemics. Proceedings of the National Academy of Sciences, 109(37), 15066-15071. doi:10.1073/pnas.1206598109Talbi, C., Lemey, P., Suchard, M. A., Abdelatif, E., Elharrak, M., Jalal, N., … Bourhy, H. (2010). Phylodynamics and Human-Mediated Dispersal of a Zoonotic Virus. PLoS Pathogens, 6(10), e1001166. doi:10.1371/journal.ppat.1001166Vijaykrishna, D., Bahl, J., Riley, S., Duan, L., Zhang, J. X., Chen, H., … Guan, Y. (2008). Evolutionary Dynamics and Emergence of Panzootic H5N1 Influenza Viruses. PLoS Pathogens, 4(9), e1000161. doi:10.1371/journal.ppat.1000161Gómez, P., Sempere, R. N., Aranda, M. A., & Elena, S. F. (2012). Phylodynamics of Pepino mosaic virus in Spain. European Journal of Plant Pathology, 134(3), 445-449. doi:10.1007/s10658-012-0019-0Lefeuvre, P., Martin, D. P., Harkins, G., Lemey, P., Gray, A. J. A., Meredith, S., … Heydarnejad, J. (2010). The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World. PLoS Pathogens, 6(10), e1001164. doi:10.1371/journal.ppat.1001164TOMITAKA, Y., & OHSHIMA, K. (2006). A phylogeographical study of the Turnip mosaic virus population in East Asia reveals an ‘emergent’ lineage in Japan. Molecular Ecology, 15(14), 4437-4457. doi:10.1111/j.1365-294x.2006.03094.xWu, B., Blanchard-Letort, A., Liu, Y., Zhou, G., Wang, X., & Elena, S. F. (2011). Dynamics of Molecular Evolution and Phylogeography of Barley yellow dwarf virus-PAV. PLoS ONE, 6(2), e16896. doi:10.1371/journal.pone.0016896MORENO, P., AMBRÓS, S., ALBIACH-MARTÍ, M. R., GUERRI, J., & PEÑA, L. (2008). Citrus tristeza virus: a pathogen that changed the course of the citrus industry. Molecular Plant Pathology, 9(2), 251-268. doi:10.1111/j.1364-3703.2007.00455.xTatineni, S., Robertson, C. J., Garnsey, S. M., & Dawson, W. O. (2011). A plant virus evolved by acquiring multiple nonconserved genes to extend its host range. Proceedings of the National Academy of Sciences, 108(42), 17366-17371. doi:10.1073/pnas.1113227108Folimonova, S. Y. (2012). Superinfection Exclusion Is an Active Virus-Controlled Function That Requires a Specific Viral Protein. Journal of Virology, 86(10), 5554-5561. doi:10.1128/jvi.00310-12Bar-Joseph, M., Marcus, R., & Lee, R. F. (1989). The Continuous Challenge of Citrus Tristeza Virus Control. Annual Review of Phytopathology, 27(1), 291-316. doi:10.1146/annurev.py.27.090189.001451Davino, S., Rubio, L., & Davino, M. (2005). Molecular analysis suggests that recent Citrus tristeza virus outbreaks in Italy were originated by at least two independent introductions. European Journal of Plant Pathology, 111(3), 289-293. doi:10.1007/s10658-003-2815-zAlbiach-Marti, M. R., Mawassi, M., Gowda, S., Satyanarayana, T., Hilf, M. E., Shanker, S., … Dawson, W. O. (2000). Sequences of Citrus Tristeza Virus Separated in Time and Space Are Essentially Identical. Journal of Virology, 74(15), 6856-6865. doi:10.1128/jvi.74.15.6856-6865.2000Rubio, L., Ayllon, M. A., Kong, P., Fernandez, A., Polek, M., Guerri, J., … Falk, B. W. (2001). Genetic Variation of Citrus Tristeza Virus Isolates from California and Spain: Evidence for Mixed Infections and Recombination. Journal of Virology, 75(17), 8054-8062. doi:10.1128/jvi.75.17.8054-8062.2001Silva, G., Marques, N., & Nolasco, G. (2011). The evolutionary rate of citrus tristeza virus ranks among the rates of the slowest RNA viruses. Journal of General Virology, 93(2), 419-429. doi:10.1099/vir.0.036574-0Mawassi, M., Mietkiewska, E., Gofman, R., Yang, G., & Bar-Joseph, M. (1996). Unusual Sequence Relationships Between Two Isolates of Citrus Tristeza Virus. Journal of General Virology, 77(9), 2359-2364. doi:10.1099/0022-1317-77-9-2359Vives, M. C., Dawson, W. O., Flores, R., L√≥pez, C., Albiach-Mart√≠, M. R., Rubio, L., … Moreno, P. (1999). The complete genome sequence of the major component of a mild citrus tristeza virus isolate. Journal of General Virology, 80(3), 811-816. doi:10.1099/0022-1317-80-3-811Martín, S., Elena, S. F., Guerri, J., Moreno, P., Sambade, A., Rubio, L., … Vives, M. C. (2009). Contribution of recombination and selection to molecular evolution of Citrus tristeza virus. Journal of General Virology, 90(6), 1527-1538. doi:10.1099/vir.0.008193-0Vives, M. C., Rubio, L., Sambade, A., Mirkov, T. E., Moreno, P., & Guerri, J. (2005). Evidence of multiple recombination events between two RNA sequence variants within a Citrus tristeza virus isolate. Virology, 331(2), 232-237. doi:10.1016/j.virol.2004.10.037D’Urso, F., Sambade, A., Moya, A., Guerri, J., & Moreno, P. (2003). Variation of haplotype distributions of two genomic regions of Citrus tristeza virus populations from eastern Spain. Molecular Ecology, 12(2), 517-526. doi:10.1046/j.1365-294x.2000.01747.xSambade, A., Rubio, L., Garnsey, S. M., Costa, N., Muller, G. W., Peyrou, M., … Moreno, P. (2002). Comparison of viral RNA populations of pathogenically distinct isolates of Citrus tristeza virus : application to monitoring cross-protection. Plant Pathology, 51(3), 257-265. doi:10.1046/j.1365-3059.2002.00720.xReed, J. C., Kasschau, K. D., Prokhnevsky, A. I., Gopinath, K., Pogue, G. P., Carrington, J. C., & Dolja, V. V. (2003). Suppressor of RNA silencing encoded by Beet yellows virus. Virology, 306(2), 203-209. doi:10.1016/s0042-6822(02)00051-xFolimonova, S. Y., Robertson, C. J., Shilts, T., Folimonov, A. S., Hilf, M. E., Garnsey, S. M., & Dawson, W. O. (2009). Infection with Strains of Citrus Tristeza Virus Does Not Exclude Superinfection by Other Strains of the Virus. Journal of Virology, 84(3), 1314-1325. doi:10.1128/jvi.02075-09Kong, P., Rubio, L., Polek, M., & Falk, B. W. (2000). Virus Genes, 21(3), 139-145. doi:10.1023/a:1008198311398Powell, C. A., Pelosi, R. R., Rundell, P. A., & Cohen, M. (2003). Breakdown of Cross-Protection of Grapefruit from Decline-Inducing Isolates of Citrus tristeza virus Following Introduction of the Brown Citrus Aphid. Plant Disease, 87(9), 1116-1118. doi:10.1094/pdis.2003.87.9.1116Roistacher C, Dodds J. (1993) Failure of 100 mild Citrus tristeza virus isolates from california to cross protect against a challenge by severe sweet orange stem pitting isolates. Proc 12th Conf IOCV: 100–107.Ayllón, M. A., Rubio, L., Sentandreu, V., Moya, A., Guerri, J., & Moreno, P. (2006). Variations in Two Gene Sequences of Citrus Tristeza Virus after Host Passage. Virus Genes, 32(2), 119-128. doi:10.1007/s11262-005-6866-4Ayllón, M. A., Rubio, L., Moya, A., Guerri, J., & Moreno, P. (1999). The Haplotype Distribution of Two Genes of Citrus Tristeza Virus Is Altered after Host Change or Aphid Transmission. Virology, 255(1), 32-39. doi:10.1006/viro.1998.9566Sentandreu, V., Castro, J. A., Ayllón, M. A., Rubio, L., Guerri, J., González-Candelas, F., … Moya, A. (2005). Evolutionary analysis of genetic variation observed in citrus tristeza virus (CTV) after host passage. Archives of Virology, 151(5), 875-894. doi:10.1007/s00705-005-0683-xMatos, L. A., Hilf, M. E., Cayetano, X. A., Feliz, A. O., Harper, S. J., & Folimonova, S. Y. (2013). Dramatic Change in Citrus tristeza virus Populations in the Dominican Republic. Plant Disease, 97(3), 339-345. doi:10.1094/pdis-05-12-0421-reDavino, S., Davino, M., Sambade, A., Guardo, M., & Caruso, A. (2003). The First Citrus tristeza virus Outbreak Found in a Relevant Citrus Producing Area of Sicily, Italy. Plant Disease, 87(3), 314-314. doi:10.1094/pdis.2003.87.3.314aRUBIO, L., AYLLONl, M. A., GUERRI, J., PAPPU, H., NIBLETT, C., & MORENO, P. (1996). Differentiation of citrus tristeza closterovirus (CTV) isolates by single-strand conformation polymorphism analysis of the coat protein gene. Annals of Applied Biology, 129(3), 479-489. doi:10.1111/j.1744-7348.1996.tb05770.xLarkin, M. A., Blackshields, G., Brown, N. P., Chenna, R., McGettigan, P. A., McWilliam, H., … Higgins, D. G. (2007). Clustal W and Clustal X version 2.0. Bioinformatics, 23(21), 2947-2948. doi:10.1093/bioinformatics/btm404Tamura, K., Peterson, D., Peterson, N., Stecher, G., Nei, M., & Kumar, S. (2011). MEGA5: Molecular Evolutionary Genetics Analysis Using Maximum Likelihood, Evolutionary Distance, and Maximum Parsimony Methods. Molecular Biology and Evolution, 28(10), 2731-2739. doi:10.1093/molbev/msr121Kosakovsky Pond, S. L., Posada, D., Gravenor, M. B., Woelk, C. H., & Frost, S. D. W. (2006). GARD: a genetic algorithm for recombination detection. Bioinformatics, 22(24), 3096-3098. doi:10.1093/bioinformatics/btl474Martin, D. P., Lemey, P., Lott, M., Moulton, V., Posada, D., & Lefeuvre, P. (2010). RDP3: a flexible and fast computer program for analyzing recombination. Bioinformatics, 26(19), 2462-2463. doi:10.1093/bioinformatics/btq467Librado, P., & Rozas, J. (2009). DnaSP v5: a software for comprehensive analysis of DNA polymorphism data. Bioinformatics, 25(11), 1451-1452. doi:10.1093/bioinformatics/btp187Kimura M. (1985) The neutral theory of molecular evolution. Cambridge Univ Pr.Weir, B. S., & Cockerham, C. C. (1984). Estimating F-Statistics for the Analysis of Population Structure. Evolution, 38(6), 1358. doi:10.2307/2408641Pond, S. L. K., & Frost, S. D. W. (2005). Datamonkey: rapid detection of selective pressure on individual sites of codon alignments. Bioinformatics, 21(10), 2531-2533. doi:10.1093/bioinformatics/bti320Drummond, A. J., & Rambaut, A. (2007). BEAST: Bayesian evolutionary analysis by sampling trees. BMC Evolutionary Biology, 7(1), 214. doi:10.1186/1471-2148-7-214Bielejec, F., Rambaut, A., Suchard, M. A., & Lemey, P. (2011). SPREAD: spatial phylogenetic reconstruction of evolutionary dynamics. Bioinformatics, 27(20), 2910-2912. doi:10.1093/bioinformatics/btr481Stamatakis, A. (2006). RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed models. Bioinformatics, 22(21), 2688-2690. doi:10.1093/bioinformatics/btl446Ott M, Zola J, Stamatakis A, Aluru S. (2007) Large-scale maximum likelihood-based phylogenetic analysis on the IBM BlueGene/L. Proceedings of the 19th ACM/IEEE conference on Supercomputing. Article No. 4.Shimodaira, H., & Hasegawa, M. (1999). Multiple Comparisons of Log-Likelihoods with Applications to Phylogenetic Inference. Molecular Biology and Evolution, 16(8), 1114-1116. doi:10.1093/oxfordjournals.molbev.a026201Soria-Carrasco, V., Talavera, G., Igea, J., & Castresana, J. (2007). The K tree score: quantification of differences in the relative branch length and topology of phylogenetic trees. Bioinformatics, 23(21), 2954-2956. doi:10.1093/bioinformatics/btm466Puigbo, P., Garcia-Vallve, S., & McInerney, J. O. (2007). TOPD/FMTS: a new software to compare phylogenetic trees. Bioinformatics, 23(12), 1556-1558. doi:10.1093/bioinformatics/btm13

    Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure.

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    Numerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N = 48,607), we identified at genome-wide significance (P = 2.7 × 10(-8) to P = 2.3 × 10(-13)) four new PP loci (at 4q12 near CHIC2, 7q22.3 near PIK3CG, 8q24.12 in NOV and 11q24.3 near ADAMTS8), two new MAP loci (3p21.31 in MAP4 and 10q25.3 near ADRB1) and one locus associated with both of these traits (2q24.3 near FIGN) that has also recently been associated with SBP in east Asians. For three of the new PP loci, the estimated effect for SBP was opposite of that for DBP, in contrast to the majority of common SBP- and DBP-associated variants, which show concordant effects on both traits. These findings suggest new genetic pathways underlying blood pressure variation, some of which may differentially influence SBP and DBP

    Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

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    The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

    Targeted agents and immunotherapies: optimizing outcomes in melanoma

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    Treatment options for patients with metastatic melanoma, and especially BRAF-mutant melanoma, have changed dramatically in the past 5 years, with the FDA approval of eight new therapeutic agents. During this period, the treatment paradigm for BRAF-mutant disease has evolved rapidly: the standard-of-care BRAF-targeted approach has shifted from single-agent BRAF inhibition to combination therapy with a BRAF and a MEK inhibitor. Concurrently, immunotherapy has transitioned from cytokine-based treatment to antibody-mediated blockade of the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and, now, the programmed cell-death protein 1 (PD-1) immune checkpoints. These changes in the treatment landscape have dramatically improved patient outcomes, with the median overall survival of patients with advanced-stage melanoma increasing from approximately 9 months before 2011 to at least 2 years - and probably longer for those with BRAF-V600-mutant disease. Herein, we review the clinical trial data that established the standard-of-care treatment approaches for advanced-stage melanoma. Mechanisms of resistance and biomarkers of response to BRAF-targeted treatments and immunotherapies are discussed, and the contrasting clinical benefits and limitations of these therapies are explored. We summarize the state of the field and outline a rational approach to frontline-treatment selection for each individual patient with BRAF-mutant melanoma

    Operation and performance of the ATLAS semiconductor tracker in LHC Run 2

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    The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules. During Run 2 (2015–2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb-1 to the ATLAS experiment at a centre-of-mass proton-proton collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector. Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2. It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%. Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules

    Safety out of control: dopamine and defence

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