5,012 research outputs found

    The Federal Reserve's Term Auction Facility

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    As liquidity conditions in the term funding markets grew increasingly strained in late 2007, the Federal Reserve began making funds available directly to banks through a new tool, the Term Auction Facility (TAF). The TAF provides term funding on a collateralized basis, at interest rates and amounts set by auction. The facility is designed to improve liquidity by making it easier for sound institutions to borrow when the markets are not operating efficiently.Federal Reserve System ; Bank liquidity ; Banks and banking

    Deuterium Fractionation: the Ariadne's Thread from the Pre-collapse Phase to Meteorites and Comets today

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    The Solar System formed about 4.6 billion years ago from a condensation of matter inside a molecular cloud. Trying to reconstruct what happened is the goal of this chapter. For that, we put together our understanding of Galactic objects that will eventually form new suns and planetary systems, with our knowledge on comets, meteorites and small bodies of the Solar System today. Our specific tool is the molecular deuteration, namely the amount of deuterium with respect to hydrogen in molecules. This is the Ariadne's thread that helps us to find the way out from a labyrinth of possible histories of our Solar System. The chapter reviews the observations and theories of the deuterium fractionation in pre-stellar cores, protostars, protoplanetary disks, comets, interplanetary dust particles and meteorites and links them together trying to build up a coherent picture of the history of the Solar System formation. We emphasise the interdisciplinary nature of the chapter, which gathers together researchers from different communities with the common goal of understanding the Solar System history.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

    Reviving trade routes: evidence from the Maputo Corridor

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    This new SSATP discussion paper reviews the experience of an apparently successful corridor to help understand optimal mix and trade-offs in reviving historical trade route. The Maputo Corridor, which had fallen in disuse during the troubled period in Mozambique, is widely regarded as one the successful corridors. It has experienced tremendous growth, attracted large industrial and transport investments, and strengthened ties between neighboring countries over its almost two decade long history since the end of the apartheid era in South Africa and the Peace Agreement in Mozambique. What makes the Maputo Corridor ideal as a source of learning lessons is that it has many contrasting facets—it is an established trade route with a development focus, as well as an hinterland corridor, a mining and resource-based corridor—whereas other corridors may have a far less diverse nature. The lessons that can be learnt from the Maputo Corridor thus have relevance for a wider variety of corridors, and can help regional economic communities, countries, corridor users and development partners to better focus their corridor strategies to maximize economic growt

    Genomic characterisation of an endometrial pathogenic <i>Escherichia coli</i> strain reveals the acquisition of genetic elements associated with extra-intestinal pathogenicity

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    &lt;b&gt;Background&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Strains of &lt;i&gt;Escherichia coli&lt;/i&gt; cause a wide variety of intestinal and extra-intestinal diseases in both humans and animals, and are also often found in healthy individuals or the environment. Broadly, a strong phylogenetic relationship exists that distinguishes most &lt;i&gt;E. Coli&lt;/i&gt; causing intestinal disease from those that cause extra-intestinal disease, however, isolates within a recently described subclass of Extra-Intestinal Pathogenic &lt;i&gt;E. Coli&lt;/i&gt; (ExPEC), termed endometrial pathogenic &lt;i&gt;E. Coli&lt;/i&gt;, tend to be phylogenetically distant from the vast majority of characterised ExPECs, and more closely related to human intestinal pathogens. In this work, we investigate the genetic basis for ExPEC infection in the prototypic endometrial pathogenic &lt;i&gt;E. Coli&lt;/i&gt; strain MS499.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt;&lt;p&gt;&lt;/p&gt; By investigating the genome of MS499 in comparison with a range of other E. coli sequences, we have discovered that this bacterium has acquired substantial lengths of DNA which encode factors more usually associated with ExPECs and less frequently found in the phylogroup relatives of MS499. Many of these acquired factors, including several iron acquisition systems and a virulence plasmid similar to that found in several ExPECs such as APEC O1 and the neonatal meningitis &lt;i&gt;E. Coli&lt;/i&gt; S88, play characterised roles in a variety of typical ExPEC infections and appear to have been acquired recently by the evolutionary lineage leading to MS499.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Taking advantage of the phylogenetic relationship we describe between MS499 and several other closely related &lt;i&gt;E. Coli&lt;/i&gt; isolates from across the globe, we propose a step-wise evolution of a novel clade of sequence type 453 ExPECs within phylogroup B1, involving the recruitment of ExPEC virulence factors into the genome of an ancestrally non-extraintestinal &lt;i&gt;E. Coli&lt;/i&gt;, which has repurposed this lineage with the capacity to cause extraintestinal disease. These data reveal the genetic components which may be involved in this phenotype switching, and argue that horizontal gene exchange may be a key factor in the emergence of novel lineages of ExPECs.&lt;p&gt;&lt;/p&gt

    Characterization of the aerosol produced by infrared femtosecond laser ablation of polyacrylamide gels for the sensitive inductively coupled plasma mass spectrometry detection of selenoproteins

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    A 2D high repetition rate femtosecondlaserablation strategy (2-mm wide lane) previously developed for the detection of selenoproteins in gel electrophoresis by inductively coupled plasma mass spectrometry was found to increase signal sensitivity by a factor of 40 compared to conventional nanosecond ablation (0.12-mm wide lane) [G. Ballihaut, F. Claverie, C. PĂ©cheyran, S. Mounicou, R. Grimaud and R. Lobinski, Sensitive Detection of Selenoproteins in Gel Electrophoresis by High Repetition Rate FemtosecondLaserAblation-Inductively Coupled Plasma Mass Spectrometry, Anal. Chem. 79 (2007) 6874–6880]. Such improvement couldn't be explained solely by the difference of amount of material ablated, and then, was attributed to the aerosol properties. In order to validate this hypothesis, the characterization of the aerosolproduced by nanosecond and high repetition rate femtosecondlaserablation of polyacrylamidegels was investigated. Our 2D high repetition rate femtosecondlaserablation strategy of 2-mm wide lane was found to produce aerosols of similar particle size distribution compared to nanosecond laserablation of 0.12-mm wide lane, with 38% mass of particles < 1 ”m. However, at high repetition rate, when the ablated surface was reduced, the particle size distribution was shifted toward thinner particle diameter (up to 77% for a 0.12-mm wide lane at 285 ”m depth). Meanwhile, scanning electron microscopy was employed to visualize the morphology of the aerosol. In the case of larger ablation, the fine particles ejected from the sample were found to form agglomerates due to higher ablation rate and then higher collision probability. Additionally, investigations of the plasma temperature changes during the ablation demonstrated that the introduction of such amount of polyacrylamidegel particles had very limited impact on the ICP source (ΔT~ 25 ± 5 K). This suggests that the cohesion forces between the thin particles composing these large aggregates were weak enough to have negligible impact on the ICPMS detection

    A Phenomenological Study of Professional and Practical Changes Experienced by Teachers Involved with Action Research in a Learning Community Master’s Program

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    In the United States, the majority of teachers have a master’s degree or higher. However, there exist concerns in the literature that having an advanced degree does not make teachers better. There thus needs to be a way to improve the outcome of a master’s degree in education so that teachers do advance their practice and bring change to their classrooms as a direct result of their experience in a master’s degree program. By focusing on the use of action research in a learning community, the intent of the present phenomenological study was to discover changes that occurred in teachers involved in action research in a learning community setting while obtaining their master’s degree. The sample consisted of teachers that have attained their master’s degree from a program involving both action research and the learning community setting offered at the same comprehensive regional university in the Upper Midwest. Based on the extant literature, it was expected that the changes experienced by the teachers may include variations in their teaching practice, professional development, collegial relationships, and leadership roles. The results of the study confirmed these changes and highlighted the development of personal control as an essential quality of effective teachers. The teachers involved in the study considered their perceived improvement as transformative and a direct result of their experience in the master’s degree program

    Laser-induced dewetting of silver-doped chalcogenide glasses

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    We report the observation of laser-induced dewetting responsible for the formation of periodic relief structures in silver-based chalcogenide thin-films. By varying the concentration of silver in the Agx(As20S80)100-x system (with x = 0, 4, 9 and 36), different surface relief structures are formed. The evolution of the surface changes as a function of laser parameters (power density, duration of exposure, and polarisation) as well as film thickness and silver concentration has been investigated. The scanning electron microscopy and atomic force microscopy images of irradiated spots show periodic ripples aligned perpendicularly to the electric field of incident light. Our results show that addition of silver into sulphur-rich chalcogenide thin-films improves the dewetting when compared to pure As20S80 thinfilms. The changes in surface morphology were attributable to photo-induced chemical modifications and a laser-driven molecular rearrangement
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