3,256 research outputs found

    Symplectically harmonic cohomology of nilmanifolds

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    This paper can be considered as an extension to our paper [On symplectically harmonic forms on six-dimensional nilmanifolds, Comment. Math. Helv. 76 (2001), n 1, 89-109]. Also, it contains a brief survey of recent results on symplectically harmonic cohomology.Comment: 18 page

    "Penny Dreadful" (2014-2016). Postmodern mythology and ontology of otherness

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    The television series Penny Dreadful (2014-2016) is an appropriation, intertextuality and transfiction exercise of four modern myths from nineteenth-century literature –Frankenstein (Mary Shelley, 1818), The Strange Case of Dr Jekyll and Mr Hyde (Robert Louis Stevenson, 1886), The Picture of Dorian Gray (Oscar Wilde, 1891) and Dracula (Bram Stoker, 1897)– to which the mythological figure of the lycanthrope is added. This myth syncretism is completed by linking these characters, located in the Victorian London of the late 19th century, with different mythologies: biblical, Egyptian, American West, Native American or witch mythology. The article aims to analyse, focusing on the final season of the series, how the narrative complexity of contemporary seriality and the different materialisations of postmodern image –multiplex-image, distance-image and excessimage– become perfect tools to both narrate the identity search of the different characters and subvert and resemantise these modern myths. Their identity searches emerge from an ontology of otherness that defines postmodernity –from otherness of conscience to otherness of other people–, using the mythical figure of the monster. It allows then the subversion and resemantisation of each mythical character, generating a kind of postmodern mythology that reflects on our contemporaneity: feminist emancipation and violent revolution, patriarchy and machismo, family institution, social marginalisation, individualism and lack of commitment, classism and racism

    Visible-light-promoted iridium(III)-catalyzed acceptorless dehydrogenation of N-Heterocycles at room temperature

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    An effective visible-light-promoted iridium(III)catalyzed hydrogen production from N-heterocycles is described. A single iridium complex constitutes the photocatalytic system playing a dual task, harvesting visible-light and facilitating C-H cleavage and H-2 formation at room temperature and without additives. The presence of a chelating C-N ligand combining a mesoionic carbene ligand along with an amido functionality in the Ir-III complex is essential to attain the photocatalytic transformation. Furthermore, the le l complex is also an efficient catalyst for the thermal reverse process under mild conditions, positioning itself as a proficient candidate for liquid organic hydrogen carrier technologies (LOHCs). Mechanistic studies support a light-induced formation of H-2 from the Ir-H intermediate as the operating mode of the iridium complex

    Adjusting the Labor Supply to Mitigate Violent Shocks: Evidence from Rural Colombia

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    This paper studies the use of labor markets to mitigate the impact of violent shocks on households in rural areas in Colombia. It examines changes in the labor supply from on-farm to off-farm labor as a means of coping with the violent shock and the ensuing redistribution of time within households. It identifies the heterogeneous response by gender. Because the incidence of violent shocks is not exogenous, the analysis uses instrumental variables that capture several dimensions of the cost of exercising terror. As a response to the violent shocks, households decrease the time spent on on-farm work and increase their supply of labor to off-farm activities (non-agricultural ones). Men carry the bulk of the adjustment in the use of time inasmuch as they supply the most hours to off-farm non-agricultural work and formal labor markets. Labor markets do not fully absorb the additional labor supply. Women in particular are unable to find jobs in formal labor markets and men have increased time dedicated to leisure and household chores. Additional off-farm supply does not fully cover the decrease in consumption. The results suggest that in rural Colombia, labor markets are a limited alternative for coping with violent shocks. Thus, policies in conflict-affected countries should go beyond short-term relief and aim at preventing labor markets from collapsing and at supporting the recovery of agricultural production.Conflict, labor markets, developing economies, instrumental variables

    The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean

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    The stable isotope composition of dissolved silicon in seawater (δ30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60∘ N) and Labrador Sea. Variations in δ30SiDSi below 500 m were closely tied to the distribution of water masses. Higher δ30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower δ30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest δ30SiDSi values were observed in the deep and abyssal eastern North Atlantic, where dense southern-sourced waters dominate. The extent to which the spreading of water masses influences the δ30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high δ30SiDSi signature is visible not only within its region of formation within the Labrador and Irminger seas, but also throughout the mid-depth western and eastern North Atlantic Ocean. Both δ30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE δ30SiDSi distribution thus provides a clear view of the direct interaction between subpolar/polar water masses of northern and southern origin, and allow examination of the extent to which these far-field signals influence the local δ30SiDSi distribution

    An evaluation of the Macarena Integral Consolidation Plan (PCIM)

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    This paper presents a description of the new strategy for the fight against drugs implemented in Colombia since the year 2007. The Strategic Leap Forward, as the Colombian government has called the program, or the Strategic Development Initiative, as the United States Agency for International Development (USAID) calls it, is a step forward in the design of anti-drug policies that are more sustainable and effective in the mid-term. Currently, a pilot project is being implemented in the Macarena region, in the department of Meta (southeast of Bogotá), where coca crops and illicit activities were the norm just a few years ago. The Colombian State, partially financed by the United States governments and European countries, consolidates its presence in this region with the different instances and programs of the state apparatus to recover territorial control and combat the production of illicit drugs. But even more important is that this new approach in the fight against illegal drugs is based on a regional economic development plan, to avoid that peasants become involved in the first stages of cocaine production and trafficking process. The adequate functioning of this strategy can be a reference point to other countries that face similar problems of illicit drug production and conflict associated with these activities.Macarena, Consolidation Plan, Colombia, Anti-drug policies

    Electrodialytic separation of Cu(II) and As(V) in acidic electrolytes

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    [ES]Se investigó el uso de la electrodiálisis para separar cobre y arsénico desde soluciones ácidas a temperatura ambiente. Se estudió el efecto de la densidad de corriente y grado de acidez del electrolito en la separación a través de experimentos en celda batch de 5 compartimientos durante 3 h. Los parámetros cinéticos indican que la velocidad de transporte de Cu(II) fue de 0,75 mol/h/m2 y de As(V) fue de 0,002 mol/h/m2 a una densidad de corriente de 225 A/m2. Se logró obtener una eficiente separación de Cu(II) y As(V), con la generación de una solución concentrada de cobre sin presencia de arsénico, lo cual fue independiente del grado de acidez de la operación y de la densidad de corriente. El efecto de la distribución de las especies iónicas de As(V) con el pH también se discute.[EN]The separation of copper and arsenic from acidic electrolytes by electrodialysis was investigated at room temperature. The effect of current density and pH was studied in a batch cell during 3 hours. The kinetic parameters showed that Cu(II) transport rate was 0.75 mol/m2/h and the As(V) transport rate was 0.002 mol/m2/h. An efficient separation between Cu(II) and As(V) was achieved; generating a concentrated solution of copper with no arsenic, which was obtained independently of the electrolyte acidity and current density used. The effect of the arsenic speciation with pH is discussed as well.Peer reviewe

    Toward Realistic Intersecting D-Brane Models

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    We provide a pedagogical introduction to a recently studied class of phenomenologically interesting string models, known as Intersecting D-Brane Models. The gauge fields of the Standard-Model are localized on D-branes wrapping certain compact cycles on an underlying geometry, whose intersections can give rise to chiral fermions. We address the basic issues and also provide an overview of the recent activity in this field. This article is intended to serve non-experts with explanations of the fundamental aspects, and also to provide some orientation for both experts and non-experts in this active field of string phenomenology.Comment: 85 pages, 8 figures, Latex, Bibtex, v2: refs added, typos correcte
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