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Small-world of communities: communication and correlation of the meta-network  [PDF]
M. Ostilli,J. F. F. Mendes
Statistics , 2008, DOI: 10.1088/1742-5468/2009/08/L08004
Abstract: Given a network and a partition in n communities, we address the issues ``how communities influence each other'' and ``when two given communities do communicate''. We prove that, for a small-world network, among communities, a simple superposition principle applies and each community plays the role of a microscopic spin governed by a sort of effective TAP (Thouless, Anderson and Palmer) equations. The relative susceptibilities derived from these equations calculated at finite or zero temperature (where the method provides an effective percolation theory) give us the answers to the above issues. As for the already studied case n=1, these equations are exact in the paramagnetic regions (at T=0 this means below the percolation threshold) and provide effective approximations in the other regions. However, unlike the case n=1, asymmetries among the communities may lead, via the TAP-like structure of the equations, to many metastable states whose number, in the case of negative short-cuts among the communities, may grow exponentially fast with n and glassy scenarios with a remarkable presence of abrupt jumps take place. Furthermore, as a byproduct, from the relative susceptibilities a natural and efficient method to detect the community structure of a generic network emerges.
Seasonal changes and interspecific correlation among the migratory waterbird communities in Tianjin
天津地区迁徙水鸟群落的季节动态及种间相关性分析

ZHANG Shu-Ping,
张淑萍

生态学报 , 2004,
Abstract: Tianjin, lying on the west shore of the Bohai Sea, is especially important as a stop-over site for waterbirds during south-north migration in China. It is important therefore to study the temporal structure of migratory waterbird communities in this area in order to understand the mechanism of waterbird's migration in the Asian Pacific Region. In addition, analyzing correlations among waterbird migration patterns, based on data from sampling key migration areas in Tianjin, will help determine interspecific ...
Mediated Communities in the Age of Electronic Communication  [PDF]
Gábor Szécsi
KOME : International Journal of Pure Communication Inquiry , 2012,
Abstract: The electronically mediated communication has transformed our notionof the relation between place and community. With a greater proportionof our communicative acts taking place via electronic media, physical co-presence, the co-located interpersonal relations are diminishing as determinants of the nature of human interactions. This paper argues that the electronically mediated communication contributes to the construction of new, mediated forms of communities which are based on the interaction or operational synthesis of virtual and physical communities. The appearance of these new forms of communitiesleads to a new conceptualization of the relation between self and community. The aim of this paper is to show that the medium of the mediatization and new conceptualization of community is a specific pictorial language of electronically mediated communication, the semantic structure of which offers new opportunities to grasp and understand the complex notion of new mediated communities and to adopt the idea of a new global, community building language in local and national communities.
Communication Communities in MOOCs  [PDF]
Nabeel Gillani,Rebecca Eynon,Michael Osborne,Isis Hjorth,Stephen Roberts
Computer Science , 2014,
Abstract: Massive Open Online Courses (MOOCs) bring together thousands of people from different geographies and demographic backgrounds -- but to date, little is known about how they learn or communicate. We introduce a new content-analysed MOOC dataset and use Bayesian Non-negative Matrix Factorization (BNMF) to extract communities of learners based on the nature of their online forum posts. We see that BNMF yields a superior probabilistic generative model for online discussions when compared to other models, and that the communities it learns are differentiated by their composite students' demographic and course performance indicators. These findings suggest that computationally efficient probabilistic generative modelling of MOOCs can reveal important insights for educational researchers and practitioners and help to develop more intelligent and responsive online learning environments.
Correlation Network Analysis Applied to Complex Biofilm Communities  [PDF]
Ana E. Duran-Pinedo, Bruce Paster, Ricardo Teles, Jorge Frias-Lopez
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028438
Abstract: The complexity of the human microbiome makes it difficult to reveal organizational principles of the community and even more challenging to generate testable hypotheses. It has been suggested that in the gut microbiome species such as Bacteroides thetaiotaomicron are keystone in maintaining the stability and functional adaptability of the microbial community. In this study, we investigate the interspecies associations in a complex microbial biofilm applying systems biology principles. Using correlation network analysis we identified bacterial modules that represent important microbial associations within the oral community. We used dental plaque as a model community because of its high diversity and the well known species-species interactions that are common in the oral biofilm. We analyzed samples from healthy individuals as well as from patients with periodontitis, a polymicrobial disease. Using results obtained by checkerboard hybridization on cultivable bacteria we identified modules that correlated well with microbial complexes previously described. Furthermore, we extended our analysis using the Human Oral Microbe Identification Microarray (HOMIM), which includes a large number of bacterial species, among them uncultivated organisms present in the mouth. Two distinct microbial communities appeared in healthy individuals while there was one major type in disease. Bacterial modules in all communities did not overlap, indicating that bacteria were able to effectively re-associate with new partners depending on the environmental conditions. We then identified hubs that could act as keystone species in the bacterial modules. Based on those results we then cultured a not-yet-cultivated microorganism, Tannerella sp. OT286 (clone BU063). After two rounds of enrichment by a selected helper (Prevotella oris OT311) we obtained colonies of Tannerella sp. OT286 growing on blood agar plates. This system-level approach would open the possibility of manipulating microbial communities in a targeted fashion as well as associating certain bacterial modules to clinical traits (e.g.: obesity, Crohn's disease, periodontal disease, etc).
Multipartite Quantum Correlation and Communication Complexities  [PDF]
Rahul Jain,Zhaohui Wei,Penghui Yao,Shengyu Zhang
Computer Science , 2014,
Abstract: The concepts of quantum correlation complexity and quantum communication complexity were recently proposed to quantify the minimum amount of resources needed in generating bipartite classical or quantum states in the single-shot setting. The former is the minimum size of the initially shared state $\sigma$ on which local operations by the two parties (without communication) can generate the target state $\rho$, and the latter is the minimum amount of communication needed when initially sharing nothing. In this paper, we generalize these two concepts to multipartite cases, for both exact and approximate state generation. Our results are summarized as follows. (1) For multipartite pure states, the correlation complexity can be completely characterized by local ranks of sybsystems. (2) We extend the notion of PSD-rank of matrices to that of tensors, and use it to bound the quantum correlation complexity for generating multipartite classical distributions. (3) For generating multipartite mixed quantum states, communication complexity is not always equal to correlation complexity (as opposed to bipartite case). But they differ by at most a factor of 2. Generating a multipartite mixed quantum state has the same communication complexity as generating its optimal purification. But for correlation complexity of these two tasks can be different (though still related by less than a factor of 2). (4) To generate a bipartite classical distribution $P(x,y)$ approximately, the quantum communication complexity is completely characterized by the approximate PSD-rank of $P$. The quantum correlation complexity of approximately generating multipartite pure states is bounded by approximate local ranks.
Utilization of Indigenous Communication Strategies in Promoting Marketing Practices in Rural Communities in Nigeria
Chris C. Chukwueah
Canadian Social Science , 2010,
Abstract: Nigerian governments, business organizations and business educators, through adult and extension education programmes have been trying to bring education and development to the door-steps of the rural dwellers. This paper examined the extent to which indigenous communication strategies are being utilized in promoting marketing practices in terms of advertising, sales promotion, public relations and publicity and personal selling in rural areas. The area of the study is Akpabuyo Local Government Area of Cross River State. 85 managers of small and medium Enterprises (SME) were used for the study. Four research questions guided the study. Findings revealed that managers of SME utilized indigenous communication strategies in their marketing practices. The integrate modern media and traditional communication strategies in marketing activities among others. It was recommended among others, that the SME managers should broaden their knowledge on the utilization of indigenous communication strategies for the promotion of marketing practices in rural communities in Nigeria. Keywords: indigenous communication strategies; rural areas; Nigeria Résumé: Grace à des programmes de l'éducation des adultes et de l'extension, les gouvernements nigérians, les organisations commerciales et les éducateurs spécialisés en commerce ont essayé de rendre l'éducation et le développement à la portée de la population rurale. Ce document a examiné la mesure dans laquelle les stratégies de communication autochtones sont utilisées dans la promotion des pratiques commerciales en matière de publicité, promotion des ventes, relations publiques, publicité et vente personnelle dans les zones rurales. La zone visée par l'étude est la zone du gouvernement local d'Akpabuyo, dans l'état de Cross River. 85 gestionnaires de petites et moyennes entreprises (PME) ont été choisis pour l'étude. Quatre questions de recherche ont orienté l'étude. Les résultats ont révélé que les gestionnaires de PME ont utilisé des stratégies de communication autochtones dans leurs pratiques commerciales. Ils ont utilisé l'intégration des médias modernes et des stratégies de communication traditionnelles dans les activités de commercialisation entre autres. Il a recommandé que les dirigeants de PME doivent élargir leurs connaissances sur l'utilisation de stratégies de communication autochtones pour la promotion de pratiques commerciales dans les communautés rurales au Nigeria. Mots-clés: stratégies de communication autochtones; collectivités rurales; Nigeria
Correlation in Hard Distributions in Communication Complexity  [PDF]
Ralph C. Bottesch,Dmitry Gavinsky,Hartmut Klauck
Computer Science , 2015,
Abstract: We study the effect that the amount of correlation in a bipartite distribution has on the communication complexity of a problem under that distribution. We introduce a new family of complexity measures that interpolates between the two previously studied extreme cases: the (standard) randomised communication complexity and the case of distributional complexity under product distributions. We give a tight characterisation of the randomised complexity of Disjointness under distributions with mutual information $k$, showing that it is $\Theta(\sqrt{n(k+1)})$ for all $0\leq k\leq n$. This smoothly interpolates between the lower bounds of Babai, Frankl and Simon for the product distribution case ($k=0$), and the bound of Razborov for the randomised case. The upper bounds improve and generalise what was known for product distributions, and imply that any tight bound for Disjointness needs $\Omega(n)$ bits of mutual information in the corresponding distribution. We study the same question in the distributional quantum setting, and show a lower bound of $\Omega((n(k+1))^{1/4})$, and an upper bound, matching up to a logarithmic factor. We show that there are total Boolean functions $f_d$ on $2n$ inputs that have distributional communication complexity $O(\log n)$ under all distributions of information up to $o(n)$, while the (interactive) distributional complexity maximised over all distributions is $\Theta(\log d)$ for $6n\leq d\leq 2^{n/100}$. We show that in the setting of one-way communication under product distributions, the dependence of communication cost on the allowed error $\epsilon$ is multiplicative in $\log(1/\epsilon)$ -- the previous upper bounds had the dependence of more than $1/\epsilon$.
EMERGENCE OF VIRTUAL COMMUNITIES AS MEANS OF COMMUNICATION: A Case Study On Virtual Health Care Communities  [PDF]
Mehpare Tokay ARGAN,Metin ARGAN,Idil K. SUHER
The Turkish Online Journal of Distance Education , 2011,
Abstract: Today, like in all areas, the Internet has had an important effect in the area of health as well. With the development of the Internet many new and different applications have developed and one of the most important of these are probably virtual communities. Virtual communities, which are used as a tool for providing information and word of mouth communication, have become a widely used marketing tool in the area of healthcare services in recent years. A virtual community is a group that does not depend on space and time to maintain ties or participation in the group whose members share the same interest and to maintain closeness, that is based on internet communications and whose membership is based on free will. In these kinds of communities whose services are provided on a membership basis, health services of various kinds are offered to the members. In virtual communities, virtual interactive communications established between the members can be an important determining factor when choosing a product, service or doctor.
Locality versus globality in bacterial signalling: can local communication stabilize bacterial communities?
Vittorio Venturi, ádám Kerényi, Beáta Reiz, Dóra Bihary, Sándor Pongor
Biology Direct , 2010, DOI: 10.1186/1745-6150-5-30
Abstract: We propose that a large microbial community can be pictured as a theatre of spontaneously emerging, partially overlapping, locally recruited microcommunities whose members interact primarily among themselves, via secreted (signalling) molecules or cell-cell contacts. We hypothesize that stability in an open environment relies on a predominantly local steady state of intercellular communication which ensures that i) deleterious mutants or strains can be excluded by a localized collapse, while ii) microcommunities harbouring useful traits can persist and/or spread even in the absence of specific protection mechanisms.Some elements of this model can be tested experimentally by analyzing the behaviour of synthetic consortia composed of strains having well-defined communication systems and devoid of specific defence mechanisms. Supporting evidence can be obtained by in silico simulations.The hypothesis provides a framework for a systematic comparison of bacterial community behavior in open and closed environments. The model predicts that local signalling may enable multispecies communities to colonize open, structured environments. On the other hand, a confined niche or a host may be more likely to be colonized by a bacterial mono-species community, and local communication here provides a control against spontaneously arising cheaters, provided that survival depends on cooperation.This article was reviewed by G. Jékely, L. Aravind and E. Szathmáry (nominated by F. Eisenhaber)Many bacteria and other unicellular organisms live in large, multispecies communities in which the participants jointly exploit the resources. Multispecies consortia are a major form of bacterial life and often contain hundreds of different species that share secreted materials in a densely packed environment. Social behaviour must be an essential trait throughout bacterial evolution [1], however there is no sufficient experimental evidence to explain why such consortia can be stable against environm
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