Dynamics and genetic structure of Argentine ant supercolonies in their native range.

Some introduced ant populations have an extraordinary social organization, called unicoloniality, whereby individuals mix freely within large supercolonies. We investigated whether this mode of social organization also exists in native populations of the Argentine ant Linepithema humile. Behavioral analyses revealed the presence of 11 supercolonies (width 1 to 515 m) over a 3-km transect. As in the introduced range, there was always strong aggression between but never within supercolonies. The genetic data were in perfect agreement with the behavioral tests, all nests being assigned to identical supercolonies with the different methods. There was strong genetic differentiation between supercolonies but no genetic differentiation among nests within supercolonies. We never found more than a single mitochondrial haplotype per supercolony, further supporting the view that supercolonies are closed breeding units. Genetic and chemical distances between supercolonies were positively correlated, but there were no other significant associations between geographic, genetic, chemical, and behavioral distances. A comparison of supercolonies sampled in 1999 and 2005 revealed a very high turnover, with about one-third of the supercolonies being replaced yearly. This dynamic is likely to involve strong competition between supercolonies and thus act as a potent selective force maintaining unicoloniality over evolutionary time

Native supercolonies of unrelated individuals in the invasive Argentine ant.

Kinship among group members has long been recognized as a main factor promoting the evolution of sociality and reproductive altruism, yet some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social organization is not only a key attribute responsible for the ecological dominance of these ants, but also an evolutionary paradox because relatedness between nestmates is effectively zero. Recently, it has been proposed that, in the Argentine ant, unicoloniality is a derived trait that evolved after its introduction into new habitats. Here we test this basic assumption by conducting a detailed genetic analysis of four native and six introduced populations with five to 15 microsatellite loci and one mitochondrial gene. In contrast to the assumption that native populations consist of family-based colonies with related individuals who are aggressive toward members of other colonies, we found that native populations also form supercolonies, and are effectively unicolonial. Moreover, just as in introduced populations, the relatedness between nestmates is not distinguishable from zero in these native range supercolonies. Genetic differentiation between native supercolonies was very high for both nuclear and mitochondrial markers, indicating extremely limited gene flow between supercolonies. The only important difference between the native and introduced populations was that supercolonies were several orders of magnitude smaller in the native range (25-500 m). This size difference has important consequences for our understanding of the evolution and stability of unicolonial structures because the relatively small size of supercolonies in the native range implies that competition can occur between supercolonies, which can act as a break on the spread of selfish mutants by eliminating supercolonies harboring them

The digital society and provision of welfare services

Purpose The purpose of this paper is to: first, explain why a new model of the provision of welfare services to citizens arises from the digital society; second explore some core elements of the competition between the new model of the provision of welfare services and the classic ideal model of the professionals’ provision of welfare services; third, suggest why it is most likely that the two models of the provision of services are combined into a symbiotic co-evolution scenario; and fourth, examine why and how this symbiotic co-evolution scenario results in new participatory spaces for the main actors associated with the provision of welfare services. Design/methodology/approach The review of the literature examines how the new model for the provision of welfare services facilitated by big data challenges the traditional professional model for the provision of welfare services. The authors use the Danish case to illustrate a number of themes related to this looking at the hospital sector as an example. Findings The proposition is that a symbiotic co-evolution scenario will emerge. A mix of the classic ideal model and practice of the service professionals’ provision of services and the digital society’s model of the provision of services is the most likely scenario in the years to come. Furthermore, Data-driven management (DDM) as an integrated key element in a symbiotic co-evolution creates (opens up) participatory environments and spaces for the main actors and agents associated with the provision of welfare services to the citizens. Research limitations/implications DDM’s impact on the provision of welfare services is still being realised and worked out, and more empirical research is needed before it is possible to point at the most likely scenario. However, according to the authors’ analytical framework, the institutional logics perspective, as presented in Section 2, a symbiotic co-evolution is most likely such that DDM will constitute a new logic within the provision of welfare services on the basis of which citizens as end-users could be provided with welfare services, but it is not likely that the new logic of DDM can displace the classic service professionals’ model of the provision of welfare services. Therefore, the new logic of DDM will be combined with and integrated into the existing logics within service provision, such as the Weberian bureaucracy, the Street-Level Bureaucracy, the New Public Governance and the Market. In spite of this, DDM can successfully be promoted by international management consulting firms, as a management concept which can remedy all the problems of the classic service professionals’ model of the provision of welfare services to citizens. Practical implications As a consequence of this, new relationships among professionals, data analytics, (middle) managers and citizens will be created regarding the provision of welfare services. Considering the new participatory environments and spaces and the new relationships among the classic service professionals, the data analytics, the (middle) managers and the citizens as end-users, the provision of welfare services may become an arena for negotiation of a new future model of the provision of welfare services to citizens. Originality/value The digital society has emerged from and developed further via: digitising, online information in almost real time, algorithms, data-informed decision-making processes, DDM and, ultimately, big data. The authors expect to see further digitising, more sophisticated algorithms and more big data. The authors suggest that a new model of the provision of welfare services to citizens will emerge from the development of the digital society. The authors also suggest that this new model will compete with the classic model of the provision of welfare services

Efficient chaining of seeds in ordered trees

We consider here the problem of chaining seeds in ordered trees. Seeds are mappings between two trees Q and T and a chain is a subset of non overlapping seeds that is consistent with respect to postfix order and ancestrality. This problem is a natural extension of a similar problem for sequences, and has applications in computational biology, such as mining a database of RNA secondary structures. For the chaining problem with a set of m constant size seeds, we describe an algorithm with complexity O(m2 log(m)) in time and O(m2) in space

Structure factor of polymers interacting via a short range repulsive potential: application to hairy wormlike micelles

We use the Random Phase Approximation (RPA) to compute the structure factor, S(q), of a solution of chains interacting through a soft and short range repulsive potential V. Above a threshold polymer concentration, whose magnitude is essentially controlled by the range of the potential, S(q) exhibits a peak whose position depends on the concentration. We take advantage of the close analogy between polymers and wormlike micelles and apply our model, using a Gaussian function for V, to quantitatively analyze experimental small angle neutron scattering profiles of semi-dilute solutions of hairy wormlike micelles. These samples, which consist in surfactant self-assembled flexible cylinders decorated by amphiphilic copolymer, provide indeed an appropriate experimental model system to study the structure of sterically interacting polymer solutions