Connections between Classical and Parametric Network Entropies

This paper explores relationships between classical and parametric measures of graph (or network) complexity. Classical measures are based on vertex decompositions induced by equivalence relations. Parametric measures, on the other hand, are constructed by using information functions to assign probabilities to the vertices. The inequalities established in this paper relating classical and parametric measures lay a foundation for systematic classification of entropy-based measures of graph complexity

The Bicoid Stability Factor Controls Polyadenylation and Expression of Specific Mitochondrial mRNAs in Drosophila melanogaster

The bicoid stability factor (BSF) of Drosophila melanogaster has been reported to be present in the cytoplasm, where it stabilizes the maternally contributed bicoid mRNA and binds mRNAs expressed from early zygotic genes. BSF may also have other roles, as it is ubiquitously expressed and essential for survival of adult flies. We have performed immunofluorescence and cell fractionation analyses and show here that BSF is mainly a mitochondrial protein. We studied two independent RNAi knockdown fly lines and report that reduced BSF protein levels lead to a severe respiratory deficiency and delayed development at the late larvae stage. Ubiquitous knockdown of BSF results in a severe reduction of the polyadenylation tail lengths of specific mitochondrial mRNAs, accompanied by an enrichment of unprocessed polycistronic RNA intermediates. Furthermore, we observed a significant reduction in mRNA steady state levels, despite increased de novo transcription. Surprisingly, mitochondrial de novo translation is increased and abnormal mitochondrial translation products are present in knockdown flies, suggesting that BSF also has a role in coordinating the mitochondrial translation in addition to its role in mRNA maturation and stability. We thus report a novel function of BSF in flies and demonstrate that it has an important intra-mitochondrial role, which is essential for maintaining mtDNA gene expression and oxidative phosphorylation

Spatial resource wars: A two region example

We develop a spatial resource model in continuous time in which two agents strategically exploit a mobile resource in a two-location setup. In order to contrast the overexploitation of the resource (the tragedy of commons) that occurs when the player are free to choose where to fish/hunt/extract/harvest, the regulator can establish a series of spatially structured policies. We compare the three situations in which the regulator: (a) leaves the player free to choose where to harvest; (b) establishes a natural reserve where nobody is allowed to harvest; (c) assigns to each player a specific exclusive location to hunt. We show that when preference parameters dictate a low harvesting intensity, the policies cannot mitigate the overexploitation and in addition they worsen the utilities of the players. Conversely, in a context of harsher harvesting intensity, the intervention can help to safeguard the resource, preventing the extinction and also improving the welfare of both players

Evolution and future of the sustainable seafood market

The sustainable seafood movement is at a crossroads. Its core strategy, also known as a theory of change, is based on market-oriented initiatives such as third-party certification but does not motivate adequate levels of improved governance and environmental improvements needed in many fisheries, especially in developing countries. Price premiums for certified products are elusive, multiple forms of certification compete in a crowded marketplace and certifiers are increasingly asked to address social as well as ecological goals. This paper traces how the sustainable seafood movement has evolved over time to address new challenges while success remains limited. We conclude by exploring four alternative potential outcomes for the future theory of change, each with different contributions to creating a more sustainable global seafood supply

Evolution and future of the sustainable seafood market

The sustainable seafood movement is at a crossroads. Its core strategy, also known as a theory of change, is based on market-oriented initiatives such as third-party certification but does not motivate adequate levels of improved governance and environmental improvements needed in many fisheries, especially in developing countries. Price premiums for certified products are elusive, multiple forms of certification compete in a crowded marketplace and certifiers are increasingly asked to address social as well as ecological goals. This paper traces how the sustainable seafood movement has evolved over time to address new challenges while success remains limited. We conclude by exploring four alternative potential outcomes for the future theory of change, each with different contributions to creating a more sustainable global seafood supply