2,323 research outputs found

    Is there club convergence in Latin America?

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    Previous studies of the income convergence hypothesis for Latin American economies indicate that almost all are not systematically closing their income gap with developed nations. The few studies to consider whether they instead exhibit club convergence—i.e., convergence to a steady-state equilibrium significantly inferior to that of the developed economies—offer little convincing evidence of this either. We argue that this reflects the limitations of their measure of relative income (which includes their sample’s average income) and/or the assumptions underlying the discrete-break unit-root tests they employ. By avoiding these limitations, we obtain evidence of two Latin American convergence clubs

    From missions to systems : generating transparently distributable programs for sensor-oriented systems

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    Early Wireless Sensor Networks aimed simply to collect as much data as possible for as long as possible. While this remains true in selected cases, the majority of future sensor network applications will demand much more intelligent use of their resources as networks increase in scale and support multiple applications and users. Specifically, we argue that a computational model is needed in which the ways that data flows through networks, and the ways in which decisions are made based on that data, is transparently distributable and relocatable as requirements evolve. In this paper we present an approach to achieving this using high-level mission specifications from which we can automatically derive transparently distributable programs.Postprin

    The politics of Anglo-American international economic relationships 1941-45

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    The thesis is an attempt to give a detailed historical narrative of a series of negotiations between the U.S. and the U.K. during the period 1941 – 1945. It is an analysis of the political controversies which arose between the two countries over economic issues. There are three main aims to the story. One is to elucidate the reasons for the economic policies pursued by the two countries, the second is the explanation of the modification of such policies and the third is to account for the subtle shifts in bargaining tactics. The account is divided into six chapters. The first chapter deals with a number of issues in an attempt to indicate some of the difference between the two countries over economic policies. The chapter includes brief descriptions of the introduction, by Britain, of economic controls and her early attempts to finance the war effort, the Atlantic Conference of 1941 and U.S.-U.K. talks on a supplement to the 1938 trade agreement. The second chapter covers the consideration for Lend-Lease talks, and chapters three and four the negotiations to establish the I.M.F. The fifth chapter deals with Anglo-American commercial talks and British attempts to have The Export White Paper of 1941 superseded. The final chapter deals with a wide range of economic talks and culminates in a detailed analysis of the talks which resulted in the U.S.-U.K. Financial Agreement of 1946. The narrative has been constructed primarily on the basis of diplomatic correspondence, cabinet and departmental papers from the P.R.O. I have also used 'The Foreign Relations of the U.S.', Hansard, the Congressional Record, both U.S. and U.K. government papers, and an extensive range of autobiographies

    Access to and use of marine genetic resources : understanding the legal framework

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    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Acknowledgements This work was supported by the PharmaSea project funded by the EU Seventh Framework Programme, and reects only the authors' views. Contract number 312184. www.pharma-sea.eu.Peer reviewedPublisher PD

    Marine metagenomics: strategies for the discovery of novel enzymes with biotechnological applications from marine environments

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    Metagenomic based strategies have previously been successfully employed as powerful tools to isolate and identify enzymes with novel biocatalytic activities from the unculturable component of microbial communities from various terrestrial environmental niches. Both sequence based and function based screening approaches have been employed to identify genes encoding novel biocatalytic activities and metabolic pathways from metagenomic libraries. While much of the focus to date has centred on terrestrial based microbial ecosystems, it is clear that the marine environment has enormous microbial biodiversity that remains largely unstudied. Marine microbes are both extremely abundant and diverse; the environments they occupy likewise consist of very diverse niches. As culture-dependent methods have thus far resulted in the isolation of only a tiny percentage of the marine microbiota the application of metagenomic strategies holds great potential to study and exploit the enormous microbial biodiversity which is present within these marine environments

    Cloning and characterization of novel methylsalicylic acid synthase gene involved in the biosynthesis of isoasperlactone and asperlactone in Aspergillus westerdijkiae

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    Aspergillus westerdijkiae is the main producer of several biologically active polyketide metabolites including isoasperlactone and asperlactone. A 5298 bp polyketide synthase gene ‘‘aomsas” has been cloned in Aspergillus westerdijkiae by using gene walking approach and RACE-PCR. The predicted amino acid sequence of aomsas shows an identity of 40–56% with different methylsalicylic acid synthase genes found in Byssochlamys nivea, P. patulum, A. terreus and Streptomyces viridochromogenes. Based on the reverse transcription PCR and kinetic secondary metabolites production studies, aomsas expression was found to be associated with the biosynthesis of isoasperlactone and asperlactone. Moreover an aomsas knockout mutant ‘‘aoDmsas” of A. westerdijkiae, not only lost the capacity to produce isoasperlactone and asperlactone,but also 6-methylsalicylic acid. The genetically complemented mutant ao+msas restored the biosynthesis of all the missing metabolites. Chemical complementation through the addition of 6-methylsalicylic acid, aspyrone and diepoxide to growing culture of aoDmsas mutant revealed that these compounds play intermediate roles in the biosynthesis of asperlactone and isoasperlactone

    Differential expression of genes involved in iron metabolism in Aspergillus fumigatus

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    The ability of fungi to survive in many environments is linked to their capacity to acquire essential nutrients. Iron is generally complexed and available in very limited amounts. Like bacteria, fungi have evolved highly specific systems for iron acquisition. Production and uptake of iron-chelating siderophores has been shown to be important for certain human bacterial pathogens, as well as in fungal pathogens such as Cryptococcus neoformans and Fusarium graminearum. This system also enables the opportunistic fungal pathogen Aspergillus fumigatus to infect and subsequently colonize the human lung. In this study, advantage was taken of genome sequence data available for both Aspergillus nidulans and A. fumigatus either to partially clone or to design PCR primers for 10 genes putatively involved in siderophore biosynthesis or uptake in A. fumigatus. The expression of these genes was then monitored by semi-quantitative and quantitative real-time PCR over a range of iron concentrations. As expected, the putative biosynthetic genes sidA, sidC and sidD were all strongly up-regulated under iron starvation conditions, although the variable degree of induction indicates complex regulation by a number of transcriptional factors, including the GATA family protein SreA. In contrast, the gene sidE shows no iron-regulation, suggesting that SidE may not be involved in siderophore biosynthesis. The characterisation of the expression patterns of this subset of genes in the iron regulon facilitates further studies into the importance of iron acquisition for pathogenesis of A. fumigatus. [Int Microbiol 2006; 9(4):281-287

    A <i>Saccharomyces cerevisiae</i> wine strain inhibits growth and decreases ochratoxin a biosynthesis by <i>Aspergillus carbonarius</i> and <i>Aspergillus ochraceus</i>

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    The aim of this study was to select wine yeast strains as biocontrol agents against fungal contaminants responsible for the accumulation of ochratoxin A (OTA) in grape and wine and to dissect the mechanism of OTA detoxification by a Saccharomyces cerevisiae strain (DISAABA1182), which had previously been reported to reduce OTA in a synthetic must. All of the yeast strains tested displayed an ability to inhibit the growth of Aspergillus carbonarius both in vivo and in vitro and addition of culture filtrates from the tested isolates led to complete inhibition of OTA production. S. cerevisiae DISAABA1182 was selected and further tested for its capacity to inhibit OTA production and pks (polyketide synthase) transcription in A. carbonarius and Aspergillus ochraceus in vitro. In order to dissect the mechanism of OTA detoxification, each of these two fungi was co-cultured with living yeast cells exposed to yeast crude or to autoclaved supernatant: S. cerevisiae DISAABA1182 was found to inhibit mycelial growth and OTA production in both Aspergilli when co-cultured in the OTA-inducing YES medium. Moreover, a decrease in pks transcription was observed in the presence of living cells of S. cerevisiae DISAABA1182 or its supernatant, while no effects were observed on transcription of either of the constitutively expressed calmodulin and β-tubulin genes. This suggests that transcriptional regulation of OTA biosynthetic genes takes place during the interaction between DISAABA1182 and OTA-producing Aspergilli

    Current Status and Future Prospects of Marine Natural Products (MNPs) as Antimicrobials

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    peer-reviewedThe marine environment is a rich source of chemically diverse, biologically active natural products, and serves as an invaluable resource in the ongoing search for novel antimicrobial compounds. Recent advances in extraction and isolation techniques, and in state-of-the-art technologies involved in organic synthesis and chemical structure elucidation, have accelerated the numbers of antimicrobial molecules originating from the ocean moving into clinical trials. The chemical diversity associated with these marine-derived molecules is immense, varying from simple linear peptides and fatty acids to complex alkaloids, terpenes and polyketides, etc. Such an array of structurally distinct molecules performs functionally diverse biological activities against many pathogenic bacteria and fungi, making marine-derived natural products valuable commodities, particularly in the current age of antimicrobial resistance. In this review, we have highlighted several marine-derived natural products (and their synthetic derivatives), which have gained recognition as effective antimicrobial agents over the past five years (2012–2017). These natural products have been categorized based on their chemical structures and the structure-activity mediated relationships of some of these bioactive molecules have been discussed. Finally, we have provided an insight into how genome mining efforts are likely to expedite the discovery of novel antimicrobial compounds

    The impact of childhood disability on family life

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    This is the second report of a study funded by the Joseph Rowntree Foundation that explored the costs to parents of bringing up a child with a severe disability. The first report, Paying to Care(Dobson and Middleton, 1998), described a minimum budget standard, which is the minimum amount that parents believed to be necessary to bring up a child with severe disabilities. This report describes the actual spending patterns of parents on 182 children with severe disabilities, and presents a detailed examination of how much parents actually spend on bringing up a severely disabled child. Fieldwork was conducted during 1997–98 and so all figures presented have been up-rated to 2000 by the Retail Price Index
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