923 research outputs found

    The impact of cluster connectedness on firm innovation: R&D effort and outcomes in the textile industry

    Get PDF
    This is an Author's Accepted Manuscript of an article published in "The impact of cluster connectedness on firm innovation: R&D effort and outcomes in the textile industry" version of the article as published in the Entrepreneurship and Regional Development, 2012 september,[copyright Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/08985626.2012.710260"[EN] Recent research into the clustering effect on firms has moved away from a simplistic view to a more complex approach. More realistic and complex causal relationships are now considered when analysing these territorial networks. Specifically, this paper attempts to analyse how cluster connect- edness moderates the relationship of a firm's innovation effort and the results obtained from this effort. We want to question the commonly accepted direct and positive impact of R&D effort, and moreover, we suggest the existence of a saturation effect and that the level of cluster's inter-connectedness in the cluster moderates this effect. We have developed our empirical study focusing on the Spanish textile industrial cluster. This is a complex manufacturing industry that uses relatively low-technology manufacturing and R&D. Our findings suggest that the degree to which a firm is involved with, or connected to, other firms in the cluster can moderate the effect of the R&D effort on its innovation results. More generally, we aim to contribute to the discussion on the degree to which firms should be involved in the cluster network in order to operate efficiently and gain the maximum competitive advantages. Our findings have implications both in recent cluster and network literature as well for institutional policy.Molina Morales, FX.; Expósito Langa, M. (2012). The impact of cluster connectedness on firm innovation: R&D effort and outcomes in the textile industry. Entrepreneurship and Regional Development. 24(7-8):685-704. doi:10.1080/08985626.2012.710260S685704247-8Agarwal, R., Audretsch, D., & Sarkar, M. B. (2007). The process of creative construction: knowledge spillovers, entrepreneurship, and economic growth. Strategic Entrepreneurship Journal, 1(3-4), 263-286. doi:10.1002/sej.36Aharonson, B. S., Baum, J. A. C., & Feldman, M. P. (2007). Desperately seeking spillovers? Increasing returns, industrial organization and the location of new entrants in geographic and technological space. Industrial and Corporate Change, 16(1), 89-130. doi:10.1093/icc/dtl034Albino, V., Carbonara, N., & Giannoccaro, I. (2006). Innovation in industrial districts: An agent-based simulation model. International Journal of Production Economics, 104(1), 30-45. doi:10.1016/j.ijpe.2004.12.023Audretsch, D. B., & Lehmann, E. E. (2005). Does the Knowledge Spillover Theory of Entrepreneurship hold for regions? Research Policy, 34(8), 1191-1202. doi:10.1016/j.respol.2005.03.012Bell, G. G. (2005). Clusters, networks, and firm innovativeness. Strategic Management Journal, 26(3), 287-295. doi:10.1002/smj.448Bell, M., & Albu, M. (1999). Knowledge Systems and Technological Dynamism in Industrial Clusters in Developing Countries. World Development, 27(9), 1715-1734. doi:10.1016/s0305-750x(99)00073-xBelussi, F., & Arcangeli, F. (1998). A typology of networks: flexible and evolutionary firms. Research Policy, 27(4), 415-428. doi:10.1016/s0048-7333(98)00074-2Cantwell, J., & Piscitello, L. (2005). Recent Location of Foreign-owned Research and Development Activities by Large Multinational Corporations in the European Regions: The Role of Spillovers and Externalities. Regional Studies, 39(1), 1-16. doi:10.1080/0034340052000320824Boschma, R. A., & ter Wal, A. L. J. (2007). Knowledge Networks and Innovative Performance in an Industrial District: The Case of a Footwear District in the South of Italy. Industry & Innovation, 14(2), 177-199. doi:10.1080/13662710701253441Brass, D. J. (1984). Being in the Right Place: A Structural Analysis of Individual Influence in an Organization. Administrative Science Quarterly, 29(4), 518. doi:10.2307/2392937Breschi, S. (2001). Knowledge Spillovers and Local Innovation Systems: A Critical Survey. Industrial and Corporate Change, 10(4), 975-1005. doi:10.1093/icc/10.4.975CALANTONE, R. (1997). New product activities and performance: The moderating role of environmental hostility. Journal of Product Innovation Management, 14(3), 179-189. doi:10.1016/s0737-6782(97)00004-0Chell, E., & Baines, S. (2000). Networking, entrepreneurship and microbusiness behaviour. Entrepreneurship & Regional Development, 12(3), 195-215. doi:10.1080/089856200413464Chung, S. (Andy), Singh, H., & Lee, K. (2000). Complementarity, status similarity and social capital as drivers of alliance formation. Strategic Management Journal, 21(1), 1-22. doi:10.1002/(sici)1097-0266(200001)21:13.0.co;2-pCockburn, I. M., & Henderson, R. M. (2003). Absorptive Capacity, Coauthoring Behavior, and the Organization of Research in Drug Discovery. The Journal of Industrial Economics, 46(2), 157-182. doi:10.1111/1467-6451.00067Cohen, W. M., & Levinthal, D. A. (1989). Innovation and Learning: The Two Faces of R & D. The Economic Journal, 99(397), 569. doi:10.2307/2233763Cohen, W. M., & Levinthal, D. A. (1990). Absorptive Capacity: A New Perspective on Learning and Innovation. Administrative Science Quarterly, 35(1), 128. doi:10.2307/2393553Coleman, J. S. (1988). Social Capital in the Creation of Human Capital. American Journal of Sociology, 94, S95-S120. doi:10.1086/228943Coombs, J. E., Deeds, D. L., & Duane Ireland, R. (2009). Placing the choice between exploration and exploitation in context: a study of geography and new product development. Strategic Entrepreneurship Journal, 3(3), 261-279. doi:10.1002/sej.74Crestanello, P., & Tattara, G. (2011). Industrial Clusters and the Governance of the Global Value Chain: The Romania–Veneto Network in Footwear and Clothing. Regional Studies, 45(2), 187-203. doi:10.1080/00343401003596299Dierickx, I., & Cool, K. (1989). Asset Stock Accumulation and Sustainability of Competitive Advantage. Management Science, 35(12), 1504-1511. doi:10.1287/mnsc.35.12.1504Dyer, J. H., & Singh, H. (1998). The Relational View: Cooperative Strategy and Sources of Interorganizational Competitive Advantage. The Academy of Management Review, 23(4), 660. doi:10.2307/259056Eraydin, A., & Armatli-Köroğlu, B. (2005). Innovation, networking and the new industrial clusters: the characteristics of networks and local innovation capabilities in the Turkish industrial clusters. Entrepreneurship & Regional Development, 17(4), 237-266. doi:10.1080/08985620500202632Evenson, R. E., & Kislev, Y. (1973). Research and Productivity in Wheat and Maize. Journal of Political Economy, 81(6), 1309-1329. doi:10.1086/260129Expósito-Langa, M., Molina-Morales, F. X., & Capó-Vicedo, J. (2011). New Product Development and Absorptive Capacity in Industrial Districts: A Multidimensional Approach. Regional Studies, 45(3), 319-331. doi:10.1080/00343400903241535Foss, N. J. (1996). Higher-order industrial Capabilities and competitive advantage. Journal of Industry Studies, 3(1), 1-20. doi:10.1080/13662719600000001George, G., Robley Wood, D., & Khan, R. (2001). Networking strategy of boards: implications for small and medium-sized enterprises. Entrepreneurship & Regional Development, 13(3), 269-285. doi:10.1080/08985620110058115Giuliani, E. 2005. The structure of cluster knowledge networks: Uneven and selective, not pervasive and collective. DRUID Working Paper no. 05-11Giuliani, E., & Bell, M. (2005). The micro-determinants of meso-level learning and innovation: evidence from a Chilean wine cluster. Research Policy, 34(1), 47-68. doi:10.1016/j.respol.2004.10.008Glasmeier, A. (1991). Technological discontinuities and flexible production networks: The case of Switzerland and the world watch industry. Research Policy, 20(5), 469-485. doi:10.1016/0048-7333(91)90070-7Grant, R. M. (1996). Prospering in Dynamically-Competitive Environments: Organizational Capability as Knowledge Integration. Organization Science, 7(4), 375-387. doi:10.1287/orsc.7.4.375Guerrieri, P., & Pietrobelli, C. (2004). Industrial districts’ evolution and technological regimes: Italy and Taiwan. Technovation, 24(11), 899-914. doi:10.1016/s0166-4972(03)00048-8Huggins, R., & Johnston, A. (2010). Knowledge flow and inter-firm networks: The influence of network resources, spatial proximity and firm size. Entrepreneurship & Regional Development, 22(5), 457-484. doi:10.1080/08985620903171350Ibarra, H. (1992). Homophily and Differential Returns: Sex Differences in Network Structure and Access in an Advertising Firm. Administrative Science Quarterly, 37(3), 422. doi:10.2307/2393451Lane, P. J., & Lubatkin, M. (1998). Relative absorptive capacity and interorganizational learning. Strategic Management Journal, 19(5), 461-477. doi:10.1002/(sici)1097-0266(199805)19:53.0.co;2-lLechner, C., Frankenberger, K., & Floyd, S. W. (2010). Task Contingencies in the Curvilinear Relationships Between Intergroup Networks and Initiative Performance. Academy of Management Journal, 53(4), 865-889. doi:10.5465/amj.2010.52814620Levin, D. Z., & Cross, R. (2004). The Strength of Weak Ties You Can Trust: The Mediating Role of Trust in Effective Knowledge Transfer. Management Science, 50(11), 1477-1490. doi:10.1287/mnsc.1030.0136Madill, J. J., Haines, G. H., & Riding, A. L. (2004). Networks and linkages among firms and organizations in the Ottawa-region technology cluster. Entrepreneurship & Regional Development, 16(5), 351-368. doi:10.1080/0898562042000188414Maskell, P. (1998). Low-Tech Competitive Advantages and the Role Of Proximity. European Urban and Regional Studies, 5(2), 99-118. doi:10.1177/096977649800500201Maskell, P. (2001). Towards a Knowledge-based Theory of the Geographical Cluster. Industrial and Corporate Change, 10(4), 921-943. doi:10.1093/icc/10.4.921McEvily, B., & Marcus, A. (2005). Embedded ties and the acquisition of competitive capabilities. Strategic Management Journal, 26(11), 1033-1055. doi:10.1002/smj.484McEvily, B., & Zaheer, A. (1999). Bridging ties: a source of firm heterogeneity in competitive capabilities. Strategic Management Journal, 20(12), 1133-1156. doi:10.1002/(sici)1097-0266(199912)20:123.0.co;2-7Xavier Molina-Morales, F., & Teresa Martínez-Fernández, M. (2006). Industrial districts: something more than a neighbourhood. Entrepreneurship & Regional Development, 18(6), 503-524. doi:10.1080/08985620600884750Molina-Morales, F. X., & Martínez-Fernández, M. T. (2009). Too much love in the neighborhood can hurt: how an excess of intensity and trust in relationships may produce negative effects on firms. Strategic Management Journal, 30(9), 1013-1023. doi:10.1002/smj.766Morrison, A. (2008). Gatekeepers of Knowledgewithin Industrial Districts: Who They Are, How They Interact. Regional Studies, 42(6), 817-835. doi:10.1080/00343400701654178Morrison, A., & Rabellotti, R. (2009). Knowledge and Information Networks in an Italian Wine Cluster. European Planning Studies, 17(7), 983-1006. doi:10.1080/09654310902949265Mowery, D. C., Oxley, J. E., & Silverman, B. S. (1996). Strategic alliances and interfirm knowledge transfer. Strategic Management Journal, 17(S2), 77-91. doi:10.1002/smj.4250171108Nahapiet, J., & Ghoshal, S. (1998). Social Capital, Intellectual Capital, and the Organizational Advantage. The Academy of Management Review, 23(2), 242. doi:10.2307/259373O’Connor, G. C. (1998). Market Learning and Radical Innovation: A Cross Case Comparison of Eight Radical Innovation Projects. Journal of Product Innovation Management, 15(2), 151-166. doi:10.1111/1540-5885.1520151Oba, B., & Semerciöz, F. (2005). Antecedents of trust in industrial districts: an empirical analysis of inter-firm relations in a Turkish industrial district. Entrepreneurship & Regional Development, 17(3), 163-182. doi:10.1080/08985620500102964Parrilli, M. D. (2009). Collective efficiency, policy inducement and social embeddedness: Drivers for the development of industrial districts. Entrepreneurship & Regional Development, 21(1), 1-24. doi:10.1080/08985620801886513Podolny, J. M., & Baron, J. N. (1997). Resources and Relationships: Social Networks and Mobility in the Workplace. American Sociological Review, 62(5), 673. doi:10.2307/2657354Porter, M. E. (1990). The Competitive Advantage of Nations. doi:10.1007/978-1-349-11336-1Pouder, R., & St. John, C. H. (1996). Hot Spots and Blind Spots: Geographical Clusters of Firms and Innovation. Academy of Management Review, 21(4), 1192-1225. doi:10.5465/amr.1996.9704071867Torre, A., & Rallet, A. (2005). Proximity and Localization. Regional Studies, 39(1), 47-59. doi:10.1080/0034340052000320842Rosenkopf, L., & Almeida, P. (2003). Overcoming Local Search Through Alliances and Mobility. Management Science, 49(6), 751-766. doi:10.1287/mnsc.49.6.751.16026Rosenthal, S. S., & Strange, W. C. (2003). Geography, Industrial Organization, and Agglomeration. Review of Economics and Statistics, 85(2), 377-393. doi:10.1162/003465303765299882Rowley, T., Behrens, D., & Krackhardt, D. (2000). Redundant governance structures: an analysis of structural and relational embeddedness in the steel and semiconductor industries. Strategic Management Journal, 21(3), 369-386. doi:10.1002/(sici)1097-0266(200003)21:33.0.co;2-mRusso, M. (1985). Technical change and the industrial district: The role of interfirm relations in the growth and transformation of ceramic tile production in Italy. Research Policy, 14(6), 329-343. doi:10.1016/0048-7333(85)90003-4Sammarra, A., & Belussi, F. (2006). Evolution and relocation in fashion-led Italian districts: evidence from two case-studies. Entrepreneurship & Regional Development, 18(6), 543-562. doi:10.1080/08985620600884685Simmie, J. (2004). Innovation and Clustering in the Globalised International Economy. Urban Studies, 41(5-6), 1095-1112. doi:10.1080/00420980410001675823Sparrowe, R. T., Liden, R. C., Wayne, S. J., & Kraimer, M. L. (2001). SOCIAL NETWORKS AND THE PERFORMANCE OF INDIVIDUALS AND GROUPS. Academy of Management Journal, 44(2), 316-325. doi:10.2307/3069458STABER, U. (2007). Contextualizing Research on Social Capital in Regional Clusters. International Journal of Urban and Regional Research, 31(3), 505-521. doi:10.1111/j.1468-2427.2007.00742.xStock, G. N., Greis, N. P., & Fischer, W. A. (2001). Absorptive capacity and new product development. The Journal of High Technology Management Research, 12(1), 77-91. doi:10.1016/s1047-8310(00)00040-7Tallman, S., Jenkins, M., Henry, N., & Pinch, S. (2004). Knowledge, Clusters, and Competitive Advantage. The Academy of Management Review, 29(2), 258. doi:10.2307/20159032Thompson, P., & Fox-Kean, M. (2005). Patent Citations and the Geography of Knowledge Spillovers: A Reassessment. American Economic Review, 95(1), 450-460. doi:10.1257/0002828053828509Tsai, W. (2001). KNOWLEDGE TRANSFER IN INTRAORGANIZATIONAL NETWORKS: EFFECTS OF NETWORK POSITION AND ABSORPTIVE CAPACITY ON BUSINESS UNIT INNOVATION AND PERFORMANCE. Academy of Management Journal, 44(5), 996-1004. doi:10.2307/3069443Tsai, W., & Ghoshal, S. (1998). SOCIAL CAPITAL AND VALUE CREATION: THE ROLE OF INTRAFIRM NETWORKS. Academy of Management Journal, 41(4), 464-476. doi:10.2307/257085Tushman, M., & Nadler, D. (1986). Organizing for Innovation. California Management Review, 28(3), 74-92. doi:10.2307/41165203Uzzi, B. (1997). Social Structure and Competition in Interfirm Networks: The Paradox of Embeddedness. Administrative Science Quarterly, 42(1), 35. doi:10.2307/2393808Varaldo, R., & Ferrucci, L. (1996). The evolutionary nature of the firm within industrial districts. European Planning Studies, 4(1), 27-34. doi:10.1080/09654319608720327Waxell, A., & Malmberg, A. (2007). What is global and what is local in knowledge-generating interaction? The case of the biotech cluster in Uppsala, Sweden. Entrepreneurship & Regional Development, 19(2), 137-159. doi:10.1080/08985620601061184Yli-Renko, H., Autio, E., & Sapienza, H. J. (2001). Social capital, knowledge acquisition, and knowledge exploitation in young technology-based firms. Strategic Management Journal, 22(6-7), 587-613. doi:10.1002/smj.183ZUCKER, L. G., DARBY, M. R., & ARMSTRONG, J. (1998). GEOGRAPHICALLY LOCALIZED KNOWLEDGE: SPILLOVERS OR MARKETS? Economic Inquiry, 36(1), 65-86. doi:10.1111/j.1465-7295.1998.tb01696.

    DSM-V: modifying the postpartum-onset specifier to include hypomania

    Get PDF
    By failing to include it under the rubric of the postpartum-onset specifier, Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV-TR has ignored the clinical reality that childbirth is a potent trigger of hypomania. Given the serious and occasionally tragic consequences of misdiagnosis of bipolar II depression as unipolar depression in the postpartum period, it is argued that DSM-V should consider modifying the postpartum-onset specifier to include episodes of hypomania

    Clinical decision support of therapeutic drug monitoring of phenytoin: measured versus adjusted phenytoin plasma concentrations

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Therapeutic drug monitoring of phenytoin by measurement of plasma concentrations is often employed to optimize clinical efficacy while avoiding adverse effects. This is most commonly accomplished by measurement of total phenytoin plasma concentrations. However, total phenytoin levels can be misleading in patients with factors such as low plasma albumin that alter the free (unbound) concentrations of phenytoin. Direct measurement of free phenytoin concentrations in plasma is more costly and time-consuming than determination of total phenytoin concentrations. An alternative to direct measurement of free phenytoin concentrations is use of the Sheiner-Tozer equation to calculate an adjusted phenytoin that corrects for the plasma albumin concentration. Innovative medical informatics tools to identify patients who would benefit from adjusted phenytoin calculations or from laboratory measurement of free phenytoin are needed to improve safety and efficacy of phenytoin pharmacotherapy. The electronic medical record for an academic medical center was searched for the time period from August 1, 1996 to November 30, 2010 for patients who had total phenytoin and free phenytoin determined on the same blood draw, and also a plasma albumin measurement within 7 days of the phenytoin measurements. The measured free phenytoin plasma concentration was used as the gold standard.</p> <p>Results</p> <p>In this study, the standard Sheiner-Tozer formula for calculating an estimated (adjusted) phenytoin level more frequently underestimates than overestimates the measured free phenytoin relative to the respective therapeutic ranges. Adjusted phenytoin concentrations provided superior classification of patients than total phenytoin measurements, particularly at low albumin concentrations. Albumin plasma concentrations up to 7 days prior to total phenytoin measurements can be used for adjusted phenytoin concentrations.</p> <p>Conclusions</p> <p>The results suggest that a measured free phenytoin should be obtained where possible to guide phenytoin dosing. If this is not feasible, then an adjusted phenytoin can supplement a total phenytoin concentration, particularly for patients with low plasma albumin.</p

    Hsp90 orchestrates transcriptional regulation by Hsf1 and cell wall remodelling by MAPK signalling during thermal adaptation in a pathogenic yeast

    Get PDF
    Acknowledgments We thank Rebecca Shapiro for creating CaLC1819, CaLC1855 and CaLC1875, Gillian Milne for help with EM, Aaron Mitchell for generously providing the transposon insertion mutant library, Jesus Pla for generously providing the hog1 hst7 mutant, and Cathy Collins for technical assistance.Peer reviewedPublisher PD

    Scientific authorships and collaboration network analysis on Chagas disease: papers indexed in PubMed (1940-2009)

    Get PDF
    Chagas disease is a chronic, tropical, parasitic disease, endemic throughout Latin America. The large-scale migration of populations has increased the geographic distribution of the disease and cases have been observed in many other countries around the world. To strengthen the critical mass of knowledge generated in different countries, it is essential to promote cooperative and translational research initiatives. We analyzed authorship of scientific documents on Chagas disease indexed in the Medline database from 1940 to 2009. Bibliometrics was used to analyze the evolution of collaboration patterns. A Social Network Analysis was carried out to identify the main research groups in the area by applying clustering methods. We then analyzed 13,989 papers produced by 21,350 authors. Collaboration among authors dramatically increased over the study period, reaching an average of 6.2 authors per paper in the last five-year period. Applying a threshold of collaboration of five or more papers signed in co-authorship, we identified 148 consolidated research groups made up of 1,750 authors. The Chagas disease network identified constitutes a "small world," characterized by a high degree of clustering and a notably high number of Brazilian researchers

    Targeting the X Chromosome during Spermatogenesis Induces Y Chromosome Transmission Ratio Distortion and Early Dominant Embryo Lethality in Anopheles gambiae

    Get PDF
    We have exploited the high selectivity of the homing endonuclease I-PpoI for the X-linked Anopheles gambiae 28S ribosomal genes to selectively target X chromosome carrying spermatozoa. Our data demonstrated that in heterozygous males, the expression of I-PpoI in the testes induced a strong bias toward Y chromosome–carrying spermatozoa. Notably, these male mosquitoes also induced complete early dominant embryo lethality in crosses with wild-type females. Morphological and molecular data indicated that all spermatozoa, irrespectively of the inheritance of the transgene, carried a substantial amount of I-PpoI protein that could attack the maternally inherited chromosome X of the embryo. Besides the obvious implications for implementing vector control measures, our data demonstrated the feasibility of generating synthetic sex distorters and revealed the intriguing possibility of manipulating maternally inherited genes using wild-type sperm cells carrying engineered endonucleases

    Targeting the X Chromosome during Spermatogenesis Induces Y Chromosome Transmission Ratio Distortion and Early Dominant Embryo Lethality in Anopheles gambiae

    Get PDF
    We have exploited the high selectivity of the homing endonuclease I-PpoI for the X-linked Anopheles gambiae 28S ribosomal genes to selectively target X chromosome carrying spermatozoa. Our data demonstrated that in heterozygous males, the expression of I-PpoI in the testes induced a strong bias toward Y chromosome–carrying spermatozoa. Notably, these male mosquitoes also induced complete early dominant embryo lethality in crosses with wild-type females. Morphological and molecular data indicated that all spermatozoa, irrespectively of the inheritance of the transgene, carried a substantial amount of I-PpoI protein that could attack the maternally inherited chromosome X of the embryo. Besides the obvious implications for implementing vector control measures, our data demonstrated the feasibility of generating synthetic sex distorters and revealed the intriguing possibility of manipulating maternally inherited genes using wild-type sperm cells carrying engineered endonucleases

    Chemical composition and antigenotoxic properties of Lippia alba essential oils

    Get PDF
    The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds

    Evidence for a Conserved Quantity in Human Mobility

    Get PDF
    Recent seminal works on human mobility have shown that individuals constantly exploit a small set of repeatedly visited locations. A concurrent study has emphasized the explorative nature of human behaviour, showing that the number of visited places grows steadily over time. How to reconcile these seemingly contradicting facts remains an open question. Here, we analyse high-resolution multi-year traces of ~40,000 individuals from 4 datasets and show that this tension vanishes when the long-term evolution of mobility patterns is considered. We reveal that mobility patterns evolve significantly yet smoothly, and that the number of familiar locations an individual visits at any point is a conserved quantity with a typical size of ~25. We use this finding to improve state-of-the-art modelling of human mobility. Furthermore, shifting the attention from aggregated quantities to individual behaviour, we show that the size of an individual’s set of preferred locations correlates with their number of social interactions. This result suggests a connection between the conserved quantity we identify, which as we show cannot be understood purely on the basis of time constraints, and the ‘Dunbar number’ describing a cognitive upper limit to an individual’s number of social relations. We anticipate that our work will spark further research linking the study of human mobility and the cognitive and behavioural sciences
    corecore