Multi-level algorithms for modularity clustering

Modularity is one of the most widely used quality measures for graph clusterings. Maximizing modularity is NP-hard, and the runtime of exact algorithms is prohibitive for large graphs. A simple and effective class of heuristics coarsens the graph by iteratively merging clusters (starting from singletons), and optionally refines the resulting clustering by iteratively moving individual vertices between clusters. Several heuristics of this type have been proposed in the literature, but little is known about their relative performance. This paper experimentally compares existing and new coarsening- and refinement-based heuristics with respect to their effectiveness (achieved modularity) and efficiency (runtime). Concerning coarsening, it turns out that the most widely used criterion for merging clusters (modularity increase) is outperformed by other simple criteria, and that a recent algorithm by Schuetz and Caflisch is no improvement over simple greedy coarsening for these criteria. Concerning refinement, a new multi-level algorithm is shown to produce significantly better clusterings than conventional single-level algorithms. A comparison with published benchmark results and algorithm implementations shows that combinations of coarsening and multi-level refinement are competitive with the best algorithms in the literature.Comment: 12 pages, 10 figures, see http://www.informatik.tu-cottbus.de/~rrotta/ for downloading the graph clustering softwar

Mudas de regeneração natural da floresta com araucária: canjarana.

bitstream/CNPF-2009-09/40848/1/Canjarana_2006.pd

Mudas de regeneração natural da floresta com araucária: bugreiro.

bitstream/item/86591/1/Folder-Bugreiro-2008.pd

Mudas de regeneração natural da floresta com araucária: imbuia.

bitstream/CNPF-2009-09/40854/1/Imbuia_2006.pd

Stato di benessere delle popolazioni di cetacei e marangone dal ciuffo nel nord Sardegna

The aim of this research study was to assess the welfare of two endangered wildlife species inhabiting the coastal area of north east Sardinia, the Bottlenose dolphin (Tursiops truncatus) and the European shag (Phalacrocorax aristotelis desmarestii). In both cases, population size and interactions with human activities were evaluated in the waters within 3 miles from the coast of the would be ‘Bocche di Bonifacio’ International Park. Bottlenose dolphin population size was estimated in 96 individuals. Behavioural observations indicated a strong interaction between bottlenose dolphin and fisheries, mostly when trammel nets fishery targeting striped red mullet were used. Concentration of organo-chloride compounds in the bubbler of stranded animals evidenced that values are comparable to those found in small cetacean inhabiting Spanish coastal areas. The presence of morbillivirus infection among the population was detected. European shag breeding pairs in the studied area were 483 in 2007. Each pair raised a mean of 1.53 fledglings. Birds found entangled in fishing nets were mostly represented by adult males. Sex ratio was determined during two consecutive reproductive seasons by DNA analysis. Obtained data evidenced that, within fledglings, males accounted for the 60% of the population. This results suggest that feeding behaviour differed between sexes and that sex ratio was adjusted because of the high mortality of males in the fishing nets. This study demonstrated that the integration of data from different disciplinary activities can contribute to the identification of the principal threats affecting target species within a protected area. This information will represent a powerful toll in designing future conservation strategies

Desenvolvimento regional e políticas sociais: um estudo do noroeste do Rio Grande do Sul na primeira década do século XXI = Regional development and social policies: a study of the northwest of Rio Grande do Sul at the first XXI century’s decade

O artigo analisa os investimentos em políticas sociais realizados pelos municípios-polo da região noroeste do estado do Rio Grande do Sul e sua possível repercussão nos indicadores de desenvolvimento. Realiza-se mapeamento do cenário de estudos a respeito do desenvolvimento regional, enfocando em como as diferentes abordagens entendem o papel representado pelas políticas sociais na dinâmica de desenvolvimento das sociedades. Demonstra-se e comparam-se os investimentos em políticas sociais em dois momentos específicos: a década de 1990 e os primeiros oito anos da década de 2000. Utilizam-se como fonte de referência os relatórios de gestão e os dados constantes na prestação de contas dos municípios junto ao Tribunal de Contas do Estado do RS. A análise da realidade das políticas sociais nesses municípios, ao longo de quase duas décadas (1991 a 2008), evidenciou transformações significativas que repercutem diretamente nos indicadores de desenvolvimento, especialmente as ligadas à área da educação e da saúd

Mudas de regeneração natural da floresta com araucária: açoita-cavalo.

bitstream/CNPF-2009-09/40850/1/AcoitaCavalo_2006.pd