33 research outputs found

    Anisotropic generalization of Stinchcombe's solution for conductivity of random resistor network on a Bethe lattice

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    Our study is based on the work of Stinchcombe [1974 \emph{J. Phys. C} \textbf{7} 179] and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi [1974 \emph{Phys. Rev. B} \textbf{9} 4575] for the regular lattice.Comment: 14 pages, 2 figure

    Awareness of alcohol advertisements and perceived influence on alcohol consumption: a qualitative study of Nigerian university students

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    Despite the growing alcohol marketing activities of the transnational alcohol industries in Nigeria, little research has focused on their effects on Nigerian youths. This study explores students’ awareness of electronic and outdoor alcohol advertisement on campus and around students’ off-campus residential and leisure sites, and the extent to which they perceive it to affect their drinking. Thirty-one in-depth interviews were conducted with male and female undergraduate students (aged 19-23 years) from a south-eastern Nigerian university. Alcohol advertisements on television, posters, billboards and the branded fences of bars are common on campus and around students’ off-campus residential and leisure spaces. While students were exposed to television alcohol advertisements aired during football games, movies and news hours, they regularly saw point-of-sale and other outdoor advertisements on and around the campus. Students demonstrated sophisticated levels of awareness of alcohol advertisements, to the extent that they ‘identified’ brand names, vividly described the advertising messages they had seen and named specific bars, restaurants and other sites where they had seen alcohol advertisements regularly. While alcohol advertisement influenced men to consume new products, it also affected their brand preference on a permanent basis. Although alcohol advertisements appear not to have influenced the women, it is argued that this was because they were exposed to the advertisements of alcoholic brands that are categorised as ‘men’s alcohol’ in Nigeria. The results suggest that while effective monitoring of electronic and outdoor advertisements should be reinforced, policymakers may consider replacing self-regulation with evidence-based alcohol control regulatory measures in Nigeria

    Intoxicating entertainment? The influence of "Star Music Trek" on the drinking practices of Nigerian students

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    Sophisticated marketing strategies are increasingly used by transnational alcohol companies in Nigeria. While this facilitates alcohol availability and encourages alcohol consumption, there are no effective policies to regulate alcohol marketing. This study draws on qualitative interviews with 31 Nigerian university students (aged 19–23 years) to explore some of the ways in which “Star Music Trek” (SMT, a brewer-sponsored music concert) establishes spaces that facilitate alcohol consumption among Nigerian youths. The data were analyzed to generate themes with the aid of NVivo 10 software. The article argues that although the rationale for attending the SMT event is to be entertained by famous artists for a reduced entrance fee, the event creates conditions that influence young people to use alcohol in diverse ways. Among nondrinkers, SMT establishes conditions that influence alcohol initiation because purchasing “Star beer,” the brand that sponsors SMT, not only serves as a ticket or gate pass to some of the concerts, but it is also the only brand sold at the event. Among those who use alcohol, SMT creates spaces that encourage a culture of intoxication because of the easy availability and accessibility of Star beer and promotional activities in the form of price reductions, raffle draws, and free drinks. The participants also discussed the ways in which the sponsor uses its marketing representatives to promote brand allegiance by encouraging attendees to favor Star beer after the concert. Overall, the findings reveal that SMT is a sophisticated marketing strategy to promote the Star brand. The study discusses the implications of the findings and concludes that effective national alcohol control policies should be formulated and implemented in Nigeria.The doctoral research, from which this article was taken was funded by the Tertiary Education Trust Fund (TETFUND)

    The influence of alcohol industry-sponsored “Gulder Ultimate Search” reality television series on the drinking behaviors of Nigerian youths

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    Background: Alcohol consumption among youths and its related problems are increasing in Nigeria. Whilst one of the reasons for this is due to the marketing activities of the transnational alcohol corporations, there are no written national alcohol control policies that regulate alcohol marketing in Nigeria. Methods: This article draws on in-depth interviews with 31 Nigerian university students (aged 19–23 years) to explore the extent to which the “Gulder Ultimate Search” (GUS) reality television show influences alcohol consumption amongst GUS contestants, television audiences and those who participate in GUS promotional activities. Results: The results show that GUS was very popular amongst students and their knowledge of the reality show was high, to the extent that they were able to identify the particular alcohol company that sponsors the reality television program, the number of contestants that compete for the prizes in each season, and what can be won by the contestants or television viewers. GUS influences the drinking behaviors of contestants because one of the criteria for participation is to present 10 or more recently used “cans” of “Gulder beer” during the screening exercise. GUS also appears to influence the drinking behaviors of television viewers and those who participate in promotions due to product placement, direct advertisements and promotional activities that accompany the “Fan-Based Edition” aspect of GUS. Conclusion: Overall, GUS is a disguised marketing strategy to promote brand awareness, and to increase sales and consumption. Alcohol control policies that regulate event sponsorship and promote public health should be implemented in Nigeria

    Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

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    In the State of Amazonas, American tegumentary leishmaniasis is endemic and presents a wide spectrum of clinical variability due to the large diversity of circulating species in the region. Isolates from patients in Manaus and its metropolitan region were characterized using monoclonal antibodies and isoenzymes belonging to four species of the parasite: Leishmania (Viannia) guyanensis, 73% (153/209); Leishmania (Viannia) braziliensis, 14% (30/209); Leishmania (Leishmania) amazonensis, 8% (17/209); and Leishmania (Viannia) naiffii, 4% (9/209). The most prevalent species was L. (V.) guyanensis. The principal finding of this study was the important quantity of infections involving more than one parasite species, representing 14% (29/209) of the total. The findings obtained in this work regarding the parasite are further highlighted by the fact that these isolates were obtained from clinical samples collected from single lesions

    Clustering with partial information

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    The Correlation Clustering problem, also known as the Cluster Editing problem, seeks to edit a given graph by adding and deleting edges to obtain a collection of vertex-disjoint cliques, such that the editing cost is minimized. The Edge Clique Partitioning problem seeks to partition the edges of a given graph into edge-disjoint cliques, such that the number of cliques is minimized. Both problems are known to be NP-hard, and they have been previously studied with respect to approximation and fixed parameter tractability. In this paper we study these two problems in a more general setting that we term fuzzy graphs, where the input graphs may have missing information, meaning that whether or not there is an edge between some pairs of vertices of the input graph can be undecided. For fuzzy graphs the Correlation Clustering and Edge Clique Partitioning problems have previously been studied only with respect to approximation. Here we give parameterized algorithms based on kernelization for both problems. We prove that the Correlation Clustering problem is fixed-parameter tractable on fuzzy graphs when parameterized by (k,r), where k is the editing cost and r is the minimum number of vertices required to cover the undecided edges. In particular we show that it has a polynomial-time reduction to a problem kernel on O(kÂČ + r) vertices. We provide an analogous result for the Edge Clique Partitioning problem on fuzzy graphs. Using (k,r) as parameters, where k bounds the size of the partition, and r is the minimum number of vertices required to cover the undecided edges, we describe a polynomial-time kernelization to a problem kernel on O(k‧3r) vertices. This implies fixed-parameter tractability for this parameterization. Furthermore we also show that parameterizing only by the number of cliques k, is not enough to obtain fixed-parameter tractability. The problem remains, in fact, NP-hard for each fixed k > 2
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