A family of discrete-time exactly-solvable exclusion processes on a one-dimensional lattice

A two-parameter family of discrete-time exactly-solvable exclusion processes on a one-dimensional lattice is introduced, which contains the asymmetric simple exclusion process and the drop-push model as particular cases. The process is rewritten in terms of boundary conditions, and the conditional probabilities are calculated using the Bethe-ansatz. This is the discrete-time version of the continuous-time processes already investigated in [1-3]. The drift- and diffusion-rates of the particles are also calculated for the two-particle sector.Comment: 10 page

Solvable multi-species extensions of the drop-push model

A family of multispecies drop-push system on a one-dimensional lattice is investigated. It is shown that this family is solvable in the sense of the Bethe ansatz, provided a nonspectral matrix equation is satisfied. The large-time behavior of the conditional probabilities, and the dynamics of the particle-type change are also investigated

Models solvable through the empty-interval method

The most general one dimensional reaction-diffusion model with nearest-neighbor interactions solvable through the empty interval method, and without any restriction on the particle-generation from two adjacent empty sites is studied. It is shown that turning on the reactions which generate particles from two adjacent empty sites, results in a gap in the spectrum of the evolution operator (or equivalently a finite relaxation time).Comment: 8 page

Annihilation-diffusion processes: an exactly solvable model

A family of diffusion-annihilation processes is introduced, which is exactly solvable. This family contains parameters that control the diffusion- and annihilation- rates. The solution is based on the Bethe ansatz and using special boundary conditions to represent the reaction. The processes are investigated, both on the lattice and on the continuum. Special cases of this family of processes are the simple exclusion process and the drop-push model.Comment: 11 pages, LaTe

Post-tsunami road reconstruction in Sri Lanka: Efficacy of mainstreaming disaster risk reduction

Following the 2004 Indian Ocean tsunami all roads in the affected areas in Sri Lanka were inaccessible during the immediate aftermath of the disaster either due to the damages they sustained or poor networking of roads and lack of contingency planning within the road network systems. This paper aims at proving the necessity of effective mainstreaming of disaster risk reduction during road reconstruction as a basic precondition for reduced exposure of road structures to hazards; improved resistance of road structures; improved resilience of authorities/teams involved in road projects. It presents the experiences of the road reconstruction sector in Sri Lanka following the 2004 Indian Ocean Tsunami. The paper discusses the perceptions of the key project stakeholders on mainstreaming disaster risk reduction and the effects of mainstreaming disaster risk reduction on vulnerability reduction. The study was empirically supported by the case study approach and independent expert interviews. This paper only presents the analysis of one case study which was conducted in a post-tsunami road reconstruction project in the Southern Sri Lanka, out of two case studies conducted within the stud

Developing an approach to assess the influence of integrating disaster risk reduction practices into infrastructure reconstruction on socio‐economic development

Purpose – Disasters provide physical, social, economic, political and environmental development windows of opportunity particularly through housing and infrastructure reconstruction. The reconstruction process should not be neglected due to the opportunistic nature of facilitating innovation in development. In this respect, post‐disaster “infrastructure” reconstruction plays a critical role in development discourse and is often essential to sustain recovery after major disasters. However, reconstruction following a natural disaster is a complicated problem involving social, economic, cultural, environmental, psychological, and technological aspects. There are significant development benefits of well‐developed “Disaster Risk Reduction (DRR) Strategies” and, for many reasons, the concept of DRR can be more easily promoted following a disaster. In this respect, a research study was conducted to investigate the effects of integrating DRR strategies into infrastructure reconstruction on enhancing the socio‐economic development process from a qualitative stance. The purpose of this paper is to document part of this research study; it proposes an approach that can be used to assess the influence of the application of the DRR concept into infrastructure reconstruction on socio‐economic development. Design/methodology/approach – The research methodology included a critical literature review. Findings – This paper suggests that the best way to assess the influence of integrating DRR strategies practices into infrastructure reconstruction on socio‐economic development is to assess the level of impact that DRR strategies has on overcoming various factors that form vulnerabilities. Having assessed this, the next step is to assess the influence of overcoming the factors that form vulnerabilities on achieving performance targets of socio‐economic development. Originality/value – This paper primarily presents a framework for the concept of socio‐economic development and a modelled classification of DRR practices

Solvable multi-species reaction-diffusion processes, including the extended drop-push model

By considering the master equation of asymmetric exclusion process on a one-dimensional lattice, we obtain the most general boundary condition of the multi-species exclusion processes in which the number of particles is constant in time. This boundary condition introduces the various interactions to the particles, including ones which have been studied yet and the new ones. In these new models, the particles have simultaneously diffusion, the two-particle interactions $A_\alpha A_\beta\to A_\gamma A_\delta$, and the $n$-particle extended drop-push interaction. The constraints on reaction rates are obtained and in two-species case, they are solved to obtain a solvable model. The conditional probabilities of this model are calculated.Comment: 14 pages. Minor changes have been done and a number of references are added. To be published in European Physical Journal

Beyond Child Soldiering: Children as Creative Entrepreneurs in Contexts of Violence in Colombia

Children in Colombia have engaged in chronic warfare since before the country’s foundation. However, current policy and intervention models targeting war-affected children in Colombia have been designed and implemented through the narrow scope of child recruitment, disregarding other dynamics of the war and representing child combatants as one-dimensional victims. Many young combatants outside the recognised armed forces are excluded from interventions and forms of support granted to child soldiers. Children residing in areas of armed conflict or other prolonged situations of violence often become perpetrators (Boyden & de Berry, 2004; Kuper, 2005; Rosen, 2005). Recent studies present evidence that many children participate in conflict of their own volition, utilising creativity and resilience to improve their circumstances (Rosen, 2005; Honwana, 2006; Hart, 2006; Rosen, 2007; Poretti, 2008; Mayall & Morrow, 2011). This study builds on these analyses by exploring the perspectives of young people with varying forms of engagement in conflict beyond child soldiering in the Colombian conflict. Utilising a combination of creative qualitative methods in workshops with young people, including audio-visual activities, capoeira, and dancing, enabled me to collect data on their responses to violence in two contrasting communities in Cali and Medellín. In learning about the trajectories of children’s lives under conditions of protracted violence and economic uncertainty in a fragmented context, this study analyses in two locations the ways young people have negotiated their daily responsibilities and developed survival strategies while employing their agency when navigating multidimensional types of violence. The analysis reveals young people’s realities and responses to interconnected forms of violence and inequalities in Colombia examining their experiences of direct engagement with violence and the structural uncertainties resulting from the protracted conflict, and how memory is used in relation to the fragmented contexts of their lives. The findings pointed to the link between the various dynamics of their participation in contexts of violence in Colombia as they shift between roles and identities beyond child soldiering; and how young people maximise opportunities and resist limiting conditions by employing their resilience as creative entrepreneurs. The thesis concludes on the one hand that it is not feasible to examine children’s engagement in the Colombian war only through the lens of child soldiering as a phenomenon on its own. On the other hand, it argues that children are not just tactical agents—making strategic decisions based on resources available to them (Honwana, 2006)—but also use their creativity and entrepreneurial agency shifting among myriad identities and roles, earning privileges and power and resisting exclusion, inequality and their limiting circumstances