15,198 research outputs found

    Fundamental Solutions and Decay of Fully Non-local Problems

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    In this paper, we study a fully non-local reaction-diffusion equation which is non-local both in time and space. We apply subordination principles to construct the fundamental solutions of this problem, which we use to find a representation of the mild solutions. Moreover, using techniques of Harmonic Analysis and Fourier Multipliers, we obtain the temporal decay rates for the mild solutions

    Analysis of two genomes from the mitochondrion-like organelle of the intestinal parasite Blastocystis: complete sequences, gene content, and genome organization.

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    Acquisition of mitochondria by the ancestor of all living eukaryotes represented a crucial milestone in the evolution of the eukaryotic cell. Nevertheless, a number of anaerobic unicellular eukaryotes have secondarily discarded certain mitochondrial features, leading to modified organelles such as hydrogenosomes and mitosomes via degenerative evolution. These mitochondrion-derived organelles have lost many of the typical characteristics of aerobic mitochondria, including certain metabolic pathways, morphological traits, and, in most cases, the organellar genome. So far, the evolutionary pathway leading from aerobic mitochondria to anaerobic degenerate organelles has remained unclear due to the lack of examples representing intermediate stages. The human parasitic stramenopile Blastocystis is a rare example of an anaerobic eukaryote with organelles that have retained some mitochondrial characteristics, including a genome, whereas they lack others, such as cytochromes. Here we report the sequence and comparative analysis of the organellar genome from two different Blastocystis isolates as well as a comparison to other genomes from stramenopile mitochondria. Analysis of the characteristics displayed by the unique Blastocystis organelle genome gives us an insight into the initial evolutionary steps that may have led from mitochondria to hydrogenosomes and mitosomes

    Generating functional analysis of complex formation and dissociation in large protein interaction networks

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    We analyze large systems of interacting proteins, using techniques from the non-equilibrium statistical mechanics of disordered many-particle systems. Apart from protein production and removal, the most relevant microscopic processes in the proteome are complex formation and dissociation, and the microscopic degrees of freedom are the evolving concentrations of unbound proteins (in multiple post-translational states) and of protein complexes. Here we only include dimer-complexes, for mathematical simplicity, and we draw the network that describes which proteins are reaction partners from an ensemble of random graphs with an arbitrary degree distribution. We show how generating functional analysis methods can be used successfully to derive closed equations for dynamical order parameters, representing an exact macroscopic description of the complex formation and dissociation dynamics in the infinite system limit. We end this paper with a discussion of the possible routes towards solving the nontrivial order parameter equations, either exactly (in specific limits) or approximately.Comment: 14 pages, to be published in Proc of IW-SMI-2009 in Kyoto (Journal of Phys Conference Series

    Do Migrants Improve Governance at Home? Evidence from a Voting Experiment

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    Can international migration promote better institutions at home by raising the demand for political accountability? In order to examine this question, we designed a behavioral measure of the population's desire for better governance. A postcard was distributed to households with the pledge that, if enough postcards were mailed back, results from a survey module on perceived corruption would be made public in the national media. Using data from a tailored household survey, we examine the determinants of our behavioral measure of demand for political accountability (i.e. of undertaking the costly action of mailing the postcard), and isolate the positive effect of international emigration using locality level variation. The estimated effects are robust to the use of instrumental variables, including both past migration and macro shocks in the migrant destination countries. We find that the estimated effects can be mainly attributed to those who emigrated to countries with better governance, especially return migrants.international migration, governance, political accountability, institutions, effects of emigration in origin countries, household survey, Cape Verde, sub-Saharan Africa.

    Do Migrants Improve Governance at Home? Evidence from a Voting Experiment

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    This paper tests the hypothesis that international migration experiences may promote better institutions at home by raising the demand for political accountability. In order to examine this question, we use a simple postcard voting experiment designed to capture the population’s desire for better governance. Using data from a tailored household survey, we examine the determinants of voting behavior in our experiment, and isolate the positive effect of international emigration on the demand for political accountability. We find that this effect can be mainly attributed to the presence of return migrants, particularly to those who emigrated to countries with better governance.international migration, household survey, governance, political accountability, institutions, effects of emigration in origin countries, Cape Verde, Sub-Saharan Africa

    Legal Corruption

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    We challenge the conventional definition of corruption as the abuse of public office for private gain, making a distinction between legal and illegal forms of corruption, and paying more attention to corporate patterns of corruption (which also affect public corruption). We undertake to identify general determinants of the pattern of legal and illegal corruption worldwide, and present a model where both corruption (modeled explicitly in the context of allocations) and the political equilibrium are endogenous. Three types of equilibrium outcomes are identified as a function of basic parameters, namely initial conditions (assets/productivity), equality, and fundamental political accountability. These equilibria are: i) an illegal corruption equilibrium, where the political elite does not face binding incentives; ii) a legal corruption equilibrium, where the political elite is obliged to incur on a cost to deceive the population; and iii) a no-corruption equilibrium, where the population cannot be deceived. An integral empirical test of the model is performed, using a broad range of variables and sources. Its core variables, namely regarding legal corruption (and other manifestations of corporate corruption) come from an original survey developed with the World Economic Forum (in the Executive Opinion Survey 2004 of the Global Competitiveness Report). The empirical results generally validate the model and explanations. Some salient implications emerge.

    Votes and Violence: Evidence from a Field Experiment in Nigeria

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    Following the wave of democratization during the 1990s, elections are now common in low-income societies. However, these elections are frequently flawed. We investigate the Nigerian general election of 2007, which is to date the largest election held in Africa and one seriously marred by violence. We designed and conducted a nationwide field experiment based on randomized anti-violence grassroots campaigning. We find direct effects on violence outcomes from exploring both subject-surveying and independent data sources. Crucially, we establish that voter intimidation is effective in reducing voter turnout, and that the violence was systematically dissociated from incumbents. We suggest that incumbents have a comparative advantage in alternative strategies, vote buying and ballot fraud. Voter intimidation may be a strategy of the weak analogous to terrorism.Violence, Conflict, Electoral Politics, Political Economy, Randomized Experiment, Field Experiment, Nigeria, West Africa

    Oxidation reactions are required to produce atranorin from acetate by alginate-immobilized cells of Cladonia verticillaris.

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    Atranorin, a p-depside of the b-orcinol series, is produced by several Cladonia species. Immobilized cells of Cladonia verticillaris in calcium alginate are able to produce atranorin when they are supplied with 1.0 mM acetate as a precursor. Production of the depside is enhanced by adding an oxidant agent (NAD+ or FMN) to the incubation media and its secretion to these media is facilitated by permeabilizing the immobilized cells with 2 % iso-propanol
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