840 research outputs found

    The manifest association structure of the single-factor model: insights from partial correlations

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    The association structure between manifest variables arising from the single-factor model is investigated using partial correlations. The additional insights to the practitioner provided by partial correlations for detecting a single-factor model are discussed. The parameter space for the partial correlations is presented, as are the patterns of signs in a matrix containing the partial correlations that are not compatible with a single-factor model

    Polysaccharide production and biofilm formation by Pseudomonas fluorescens: effects of pH and surface material

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    Although the synthesis of extracellular polysaccharides was first recognized in certain bacterial cultures a long time ago, its role in bacterial adhesion is still subject to some debate. Several fermentation batch cultures were performed under different conditions of pH (pH 7, maintained with NaOH and HCl; pH 7 in phosphate buffer, and without pH control) in order to study the relation between the production of extracellular polysaccharides and biofilm formation on polymeric slides suspended in the culture medium. The polymers used were polystyrene, polypropylene, polyethylene and poly(vinyl chloride). The maximum amount of exopolysaccharides in the culture medium occurs at pH 7, although slightly thicker biofilms seem to be formed when there is no pH control. The biofilms were analysed by scanning electron microscopy and by wavelength dispersion spectroscopy. Biofilm morphology seems to be much more dependent on the type of substratium than on the pH of the medium; for different pH values, a polymeric network can be more clearly observed on biofilms formed on all surfaces except poly(vinyl chloride)

    Deploying the WTO Agreement on Government Procurement (GPA) to Enhance Sustainability and Accelerate Climate Change Mitigation

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    Mitigating climate change and promoting sustainability are defining challenges of our time. Public procurement has a vital role to play in responding to the current crises. This article makes the case that the World Trade Organization’s (WTO) Agreement on Government Procurement (GPA), and specifically the Work Programme on Sustainable Procurement that has been initiated pursuant to the Agreement, can serve as important instruments to promote sustainable approaches to public procurement internationally, consistent with the goals of climate change mitigation. The Work Programme, which was established at the time of the GPA’s modernization in 2012 and on which important work has already been done but which has recently been relatively dormant, mandates the Organization’s Committee on Government Procurement to study, inter alia, “the ways in which sustainable procurement can be practiced in a manner consistent with Parties’ international trade obligations ”and to prepare a report that sets out best practices concerning relevant measures and polices. This provides an essential and attractive platform for responding to the crisis. The article sets out important related background, including with respect to: (i) a “change of mindset” with respect to environmental sustainability which is already embodied in the amended GPA text adopted in 2012; (ii) existing GPA provisions that provide windows of opportunity for the advancing of related objectives; and (iii) importantly, ongoing developments in key GPA Parties and at the international level that both: (a) point the way toward meaningful change; and (b) suggest, in our view, a need for a modest degree of international coordination to avoid conflict and ensure continuing market openness. These developments portend a rich agenda of possibilities for further discussions in the WTO Work Programme

    Lavandula luisieri and Lavandula viridis essential oils as upcoming anti-protozoal agents: A key focus on leishmaniasis

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    Background and objectives: Leishmania species is the causative agent of leishmaniasis, a broad-spectrum clinical condition that can even be life-threatening when neglected. Current therapeutic strategies, despite beings highly cost-effective, have been increasingly associated with the appearance of drug-resistant microorganisms. Thus, an increasing number of thorough studies are needed towards upcoming drug discovery. This study aims to reveal the anti-protozoa activity of Lavandula luisieri and Lavandula viridis essential oils (EO) and their main components (1,8-cineole, linalool, and borneol). Materials and Methods: L. luisieri and L. viridis EO and their main components' leishmanicidal effects were tested in vitro against Leishmania infantum, Leishmania major, and Leishmania tropica strains. Cell viability effects were estimated by using the tetrazolium-dye (MTT) colorimetric method, morphological changes were assessed by scanning electron microscopy (SEM) and ultrastructural investigation by transmission electronic microscopy (TEM). Phosphatidylserine externalization, mitochondrial membrane potential (MMP), and cathepsin D activity assessment were also carried out. Finally, cytotoxic activity of the studied matrices was also determined in mammalian cells. Results: Plant-studied EO exhibited prominent anti-Leishmania effects (IC50 = 31-263 µg/mL), with L. luisieri being the most active one. At concentrations corresponding to IC50 values, EO-exposed L. infantum promastigotes suffered marked ultrastructural modifications. The presence of aberrant-shaped cells, mitochondrial and kinetoplast swelling, and autophagosomal structures were the most common evidenced changes. L. luisieri EO exerted its leishmanicidal activity through different mechanisms, but mainly through unleashing apoptosis. Phosphatidylserine externalization, mitochondrial membrane potential loss, and cell-cycle arrest at G(0)/G(1) phase were the most remarkable apoptosis-mediated aspects. Inhibition of cathepsin D activity was also observed. No toxic effects were found on macrophage cells. Conclusions: L. luisieri seems to be an upcoming source of bioactive molecules for leishmaniasis control and to find leading molecules for new drugs formulation against Leishmania infections.This work was supported by the European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme under project CENTRO-01-0145-FEDER-000008:BrainHealth 2020, and through the COMPETE 2020—Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT—Fundação para a Ciência e a Tecnologia, I.P., under strategic project POCI-01-0145-FEDER-007440 (UID/NEU/04539/2013). Acknowledgments: The authors are grateful to Jorge Paiva for helping in plant taxonomy; to José Correia da Costa from Centro de Imunologia e Biologia Parasitária, Instituto Nacional Ricardo Jorge, Porto for supplying L. infantum (zymodeme MON-1); to António Osuna, Departamento de Parasitología, Facultad de Ciencias, Instituto de Biotecnología, Universidad de Granada, for supplying L. major. FCT for Strategic project ref. UID/BIM/04293/2013, and “NORTE2020—Programa Operacional Regional do Norte” (NORTE-01-0145-FEDER-000012)

    Climate adaptation pathways and the role of social-ecological networks in small-scale fisheries

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    Climate change is expected to have increasing impacts on marine ecosystems which will threaten the livelihoods and wellbeing of millions of people. Drawing on social-ecological network and sociodemographic data collected via face-to-face interviews with 404 small-scale commercial fishers from 9 Galician communities (Spain), we empirically examine the adaptation pathways that fishers follow when they face hypothetical impacts on their fishery resources and test the role of five social-ecological network structures on fisher’s stated intended responses to such scenarios. Our results show that fishers generally intend to follow a ‘remain—adapt—transform—exit (the fishery)’ pathway when faced with increasing climate impacts. Next, we demonstrate that trust-based bonding ties and ties to informal leaders are associated with a ‘business-as-usual’ strategy. In contrast, communicative bonding ties are associated with adaptive responses, while communicative bridging ties are associated with transformative and exit strategies. Our findings provide key empirical insight that broaden our understanding of the intricate relationship between social networks and adaptive behaviour relevant to social-ecological systems worldwide.Xunta de GaliciaAustralian Research Council | Ref. DE19010158

    Transformation in times of climate change: what makes a fisher diversify livelihoods?

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    Despite the importance of livelihood diversification as a transformation strategy in small-scale fisheries facing climate change, empirical evidence on this complex phenomenon is scarce. This work aims to shed light on factors that help to explain the transformative behavior of small-scale fishers when faced with climate change impacts. Using primary survey data from 404 small-scale fishers across 9 communities in Galicia, NW Spain, we examined how different aspects of fishers’ adaptive capacities relate to their stated decisions to engage in livelihood diversification when faced with hypothetical climate change scenarios. The results of our multinomial multilevel mixed-effect logit model show that flexibility (current income diversification level and diversity of target fishery resources) has a strong, positive relationship with livelihood diversification responses. In contrast, learning, social organization, and competing concerns played a complex role. Specifically, we found that social-ecological system knowledge, communication with different fishing groups (bridging communication), trust in institutional actors, and gender (female) were positively related to livelihood diversification when faced with climate impacts. Fishing experience, communication within fishing groups (bonding communication), and trust in other fishing groups (bridging trust) were negatively related to diversification. Our results provide new empirical evidence on the factors associated with fisher’s decisions to engage in livelihood diversification when faced with climate impacts on fishery resources, lending critical insight for climate adaptation programs and policies.Axencia Galega de InnovaciónXunta de GaliciaAustralian Research Counci

    Modelling the Recoherence of Mesoscopic Superpositions in Dissipative Environments

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    A model is presented to describe the recently proposed experiment (J. Raimond, M. Brune and S. Haroche Phys. Rev. Lett {\bf 79}, 1964 (1997)) where a mesoscopic superposition of radiation states is prepared in a high-Q cavity which is coupled to a similar resonator. The dynamical coherence loss of such state in the absence of dissipation is reversible and can in principle be observed. We show how this picture is modified due to the presence of the environmental couplings. Analytical expressions for the experimental conditional probabilities and the linear entropy are given. We conclude that the phenomenon can still be observed provided the ratio between the damping constant and the inter-cavities coupling does not exceed about a few percent. This observation is favored for superpositions of states with large overlap.Comment: 13 pages, 6 figure
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