Fluid Queue Driven by an M

This paper deals with the stationary analysis of a fluid queue driven by an M/M/1 queueing model subject to Bernoulli-Schedule-Controlled Vacation and Vacation Interruption. The model under consideration can be viewed as a quasi-birth and death process. The governing system of differential difference equations is solved using matrix-geometric method in the Laplacian domain. The resulting solutions are then inverted to obtain an explicit expression for the joint steady state probabilities of the content of the buffer and the state of the background queueing model. Numerical illustrations are added to depict the convergence of the stationary buffer content distribution to one subject to suitable stability conditions

Studying essential DNA metabolism proteins in Xenopus egg extract

The correct duplication of genetic information is essential to maintain genome stability, which is lost in cancer cells. Replication fork integrity is ensured by a number of DNA metabolism proteins that assist replication of chromatin regions difficult to replicate due to their intrinsic DNA sequence composition, coordinate repair of DNA molecules resulting from aberrant replication events or protect replication forks in the presence of lesions impairing their progression. Some DNA metabolism genes involved in DNA repair are essential in higher eukaryotes even in unchallenged conditions, suggesting the existence of biological processes requiring these specialized functions in organisms with complex genomes. The impact on cell survival of null mutants of many DNA metabolism genes has precluded complete in depth analysis of their function. Cell free extracts represent a fundamental tool to overcome survival issues. The Xenopus laevis egg cell free extract is an ideal system to study replication-associated functions of essential genes. We are taking advantage of this system together with innovative imaging and proteomic based experimental approaches to characterize the molecular function of essential DNA metabolism proteins. Using this approach we have uncovered the role of some essential homologous recombination and fork protection proteins in chromosomal DNA replication and we have characterized some of the factors required for faithful replication of specific vertebrate genomic regions. This approach will be instrumental to study the molecular mechanisms underlying the function of a number of essential DNA metabolism proteins involved in the maintenance of genome stability in complex genomes

The green economy as plantation ecology: When dehumanization and ecological simplification go 'green'

The green economy is proposed as a solution to address growing and potentially irreversible ecological crises. But what happens when environmental solutions are premised on the same logics of brutal simplification and dehumanization that sustain and reinforce systems of oppression and ecological breakdown? In this article, we describe the transformation of the biophysical landscape of the planet into replicable blueprints of the plantation plot. The plantation as a colonial-era organizational template is an ongoing ecological process premised on disciplining bodies and landscapes into efficient, predictable, calculable, and controllable plots to optimize commodity production and is dependent on racialized and gendered processes of dehumanization. The visible cultural, physical, aesthetic, and political singularity of the plot, under the guise of objectivity and neutrality, permits a tangible depiction of the way ecological breakdown takes place. We interrogate the notion of "greening" as a strategy to combat the unintended impacts of colonial plantation ecology, arguing that such tactics further reinforce the template of plantation ecology rather than dismantle it. We first conceptualize the historical plantation and its biophysical, cognitive, and corporeal organizational principles. We then offer examples of "greening" as new, more inclusive (but equally detrimental) forms of plantation logics, and crucially identify how these extensions of plantation logic get co-opted by resistance agents, from social movements to disease and pestilence. We consider sustainability certifications of palm oil through the Roundtable on Sustainable Palm Oil (RSPO) in Colombia and compensatory afforestation programs designed to offset forest destruction through monoculture plantations in India. We conclude by highlighting how abolition ecologies can serve as an antidote to plantation logic and highlight necessary relationships of self-reflexivity, repair and collective solidarity required to disinvest in plantation ecology

The “Greening” of Empire: The European Green Deal as the EU first agenda

The recent past has seen the proposal of multiple ‘Green New Deals’ across geographies as a means to fight against the climate crisis and ecological breakdown. Of these, the European Green Deal- EGD represents the world's first public commitment to reduce greenhouse gas emissions of at least 55% by 2030 compared to 1990 levels. Because the EGD plans to “transform the EU,” in this paper we examine how it fits within a historical continuum of colonial and neo-colonial relations. We argue that the EGD is the latest discursive strategy for the ‘greening' of empire through four registers: (1) turning ecological crises into profitable opportunities; (2) portraying the EU as a ‘moral’ intervener; (3) building on a ‘green' “will to improve”; and (4) securitizing and consolidating the empire. We find how the EU acts in key policy arenas of diplomacy, trade and investment leading to the ‘greening' of the empire that ensures its continued economic and political leadership while fundamentally maintaining a status quo. We conclude with some reflections on the role of the EU to cede place to other possibilities of building anti-colonial ecologies

PrimPol-dependent single-stranded gap formation mediates homologous recombination at bulky DNA adducts

Stalled replication forks can be restarted and repaired by RAD51-mediated homologous recombination (HR), but HR can also perform post-replicative repair after bypass of the obstacle. Bulky DNA adducts are important replication-blocking lesions, but it is unknown whether they activate HR at stalled forks or behind ongoing forks. Using mainly BPDE-DNA adducts as model lesions, we show that HR induced by bulky adducts in mammalian cells predominantly occurs at post-replicative gaps formed by the DNA/RNA primase PrimPol. RAD51 recruitment under these conditions does not result from fork stalling, but rather occurs at gaps formed by PrimPol re-priming and resection by MRE11 and EXO1. In contrast, RAD51 loading at double-strand breaks does not require PrimPol. At bulky adducts, PrimPol promotes sister chromatid exchange and genetic recombination. Our data support that HR at bulky adducts in mammalian cells involves post-replicative gap repair and define a role for PrimPol in HR-mediated DNA damage tolerance

A critical examination of payments for ecosystem services (PES) as applied in a watershed management context

The present research contributes to the trend of critical analysis of Payments for Ecosystem Services (PES) by: a) developing a novel governance framework for ecosystem services in a watershed context; b) applying a methodological tool for assessing technical and social complexities for socio-ecological conflicts to a proposed PES scheme for watershed management; c) linking ecosystem services to discrete improvements in human well-being through a consideration of Amartya Sen’s ‘capabilities approach’; d) exposing the trade-offs implicit in targeting payment schemes for diverse objectives, and e) exploring the behavioural economics assumptions of PES in a context at the frontier of the free-market and exchange values for public goods and services. Few studies examining PES feasibility have taken an explicitly justice-oriented lens to considering fairness, equity for ensuring long-term negotiation outcomes. Two empirical studies are provided based upon a proposed PES scheme in the Shivapuri-Nagarjun National Park located in the Kathmandu Valley of Nepal. The first of these illustrates how market-based logic in spatially optimising payments fails to resonate with social institutions and values and inadvertently separates society from nature in a piecemeal fashion. Spatial interpolation according to household characteristics was employed using ArcGIS to map areas of low opportunity cost, ecological vulnerability and poverty. These maps were compared with the preferences, constraints, and informal institutions of upstream service providers to illustrate trade-offs between externally determined PES targeting designs and local legitimacy. It is argued that the mechanistic ‘puzzle-matching’ of targeting payments according to efficiency and effectiveness continues to treat society as separate from nature and risks reinforcing perceived inequities. The second study uses social multi-criteria evaluation as an alternative methodology for designing a number of PES and other management alternatives for Shivapuri-Nagarjun National Park. This method is based upon a deliberative negotiation of values, priorities and opportunities for improving individual and collective well-being and which do not allow for certain value sets to compensate others, but to expose the trade-offs inherent between equally legitimate perspectives.A final empirical study carried out at a pilot watershed PES programme in the Kyrgyz Republic examines the behavioural aspects of rational self-interest which characterise the assumed motivations underlying participation in PES schemes. Scholarship in the field of behavioural economics has illustrated how decentralised norm enforcement, norms of reciprocity, framing and image motivation may explain behaviour in social settings that override assumptions of purely rational and self-interested actors. In this study, different sets of incentives and framings of incentives are introduced to examine the extent to which they motivate participation in the maintenance and repair of collectively owned irrigation canals. The exploratory study illustrates that the prioritisation of self-interested norms over existing social institutions can result in unintentional outcomes depending on the framing and strength of different sets of norms in a given context. The implications of this thesis suggest that incentive-provision for watershed services has greater potential to be integrated within collective resource management than as a market-based tool. Appreciating the effect of incentive provision to encourage greater collective action can offer few generalising heuristics with the exception of efforts which facilitate or reinforce existing social institutions and norms and place recognition and procedural justice as core components of negotiated outcomes.Le vif intérêt que suscitent actuellement les mécanismes de "Paiements pour les services écosystèmiques" (PSE) pour la gestion des ressources naturelles est supporté par une argumentation fondamentalement économique sur laquelle l’importance accordée à l’efficacité supplante les politiques de préservation et les initiatives communautaires pour la conservation de la nature, car ces dernières manquent d’obligations conditionnelles à l’entretien de la terre. La logique économique qui sous-tend les PSE se réfère à l’internalisation des coûts sociaux liés à la détérioration des ressources naturelles. Les services écosystèmiques étant de nouveaux produits produits (ou objets d’échange) à l’échelle du marché incarnent de meilleures déterminants dans la prise de décisions. La présente recherche propose une analyse conceptuelle critique et empirique dans le cadre des PSE fondés sur les principes du marché afin d’avancer la gestion de l’eau intégrée et adaptée. La complexité des caractéristiques économiques, spatiales et temporelles des services économiques de même que les valeurs diverses souvent conflictuelles, pousse la recherche actuelle à reconnaître les jeux de pouvoirs définissant la base des PSE en tant qu’instrument économique. Un cadre conceptuel est développé pour démontrer le décalage existant entre la caractérisation des services écosystèmiques en tant que biens économiques et leurs traitements dans le contexte des PSE comme produit d’échange. Deux études empiriques ont été effectuées basées sur un projet de PSE prévoyait à la Vallée de Katmandou au Népal. La première de ces études illustre le revers de l’application des instruments économiques en ciblant l’optimisation des paiements dans une logique de marché, car via une vision divisant la nature et la société, ces instruments faillissent à atteindre les institutions sociales et les valeurs. La deuxième étude utilise l’évaluation sociale multicritère comme approche délibérant pour conceptualiser des incitatifs à la gestion des ressources naturelles à travers un processus de négociations ouvert à la communication des valeurs, priorités et opportunités pour l’amélioration due bien-être collectif et individuel. Cette évaluation ne permet pas la compensation d’un groupe par l’usage d’une valeur, mais incite plutôt la réalisation des échanges nécessaires à l’élaboration d’un compromis entre les perspectives des groupes impliqués. La dernière étude empirique à été réalisé sur un site pour une étude de cas pilote d’implantation des PSE à un bassin versant au Kirghizstan. Le but de cette étude est d’investiguer les aspects comportementaux de l’intérêt personnel-rationnel motivant la participation des individus à s’inscrire à un projet de PSE. Cette étude exploratoire à démontré la prépondérance accordée à l’intérêt personnel-rationnel par rapport aux règles sociales collectives, ce qui peut produire des résultats non-désirés en fonction du contexte, de l’encadrement et des normes sociales déjà en place dans le lieu d’implantation. Les implications de cette recherche indiquent que la promotion des incitatifs pour la gestion de l’eau sont mieux positionné sous la théorie de l’action collective et la gestion des biens communs qu’en tant qu’outil de marché. En effet, l’encadrement des paiements en tant qu’internalisation des externalités du marché restent trop à l’écart des réalités des asymétries hors de contacte de pouvoir scalaires et des incertitudes temporelles qui exacerbent les inégalités ce qui mène à des impacts écologiques négatifs. Par contre, bien que les heuristiques de bonnes pratiques ne peuvent être généralisés, la justice procédurale et la reconnaissance des valeurs diverses sont des éléments fondamentaux des résultats négociés