relation: http://eprints.imtlucca.it/2188/ title: Network communities within and across borders creator: Cerina, Federica creator: Chessa, Alessandro creator: Pammolli, Fabio creator: Riccaboni, Massimo subject: H Social Sciences (General) subject: HA Statistics subject: HB Economic Theory description: We investigate the impact of borders on the topology of spatially embedded networks. Indeed territorial subdivisions and geographical borders significantly hamper the geographical span of networks thus playing a key role in the formation of network communities. This is especially important in scientific and technological policy-making, highlighting the interplay between pressure for the internationalization to lead towards a global innovation system and the administrative borders imposed by the national and regional institutions. In this study we introduce an outreach index to quantify the impact of borders on the community structure and apply it to the case of the European and US patent co-inventors networks. We find that (a) the US connectivity decays as a power of distance, whereas we observe a faster exponential decay for Europe; (b) European network communities essentially correspond to nations and contiguous regions while US communities span multiple states across the whole country without any characteristic geographic scale. We confirm our findings by means of a set of simulations aimed at exploring the relationship between different patterns of cross-border community structures and the outreach index. publisher: Nature Publishing Group date: 2014 type: Article type: PeerReviewed format: application/pdf language: en rights: cc_by_nd identifier: http://eprints.imtlucca.it/2188/1/Scientific_report_Pammolli_Riccaboni_Chessa_2014.pdf identifier: Cerina, Federica and Chessa, Alessandro and Pammolli, Fabio and Riccaboni, Massimo Network communities within and across borders. Scientific Reports, 4. pp. 1-7. ISSN 2045-2322 (2014) relation: http://dx.doi.org/10.1038/srep04546 relation: 10.1038/srep04546