  In this work we study international migrations of researchers, scientists,
and academics from a complex-network perspective to identify the central
countries involved in the migration phenomenon. We define the scientific
migration network (SMN) as temporal directed weighted network where nodes are
world countries, links account for the number of scientists moving from one
country to another, and timestamps represent years (from 2000 to 2016). 2.8
millions ORCID public profiles are utilized as data source. We then
characterize hubs and authorities of the SMN employing the well-know weighted
hyperlink-induced topic search (HITS) algorithm to catch the interplay between
providing and attracting researchers from a global perspective, and relate
these results to other local and global methodologies. We also investigate the
local characteristics of successors of hubs and predecessors of authorities to
dive deeper into the motivations that establish hubs and authorities as such.
Our findings highlight the presence of a set of countries acting both as hubs
and authorities, occupying a privileged position in the scientific migration
network, and having similar local characteristics. Finally, we showcase how to
employ network visualization to evince temporal evolutions of ego-networks of
selected hubs and authorities.
