703 research outputs found

    Foreword to International Environmentalism: A Global Approach to Global Challenges

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    As the effects of climate change progress, people and governments in every country are left grappling with how to combat the consequences. Recognizing that such global challenges necessitate an international approach, this Symposium was convened to critically examine the domestic application of international law, the role of non-governmental organizations (“NGOs”), transnational ecological harms, and international environmental agreements. Articles and contributions from panelists in the Symposium contemplated the best paths forward in the face of an ever-changing international landscape. This abstract has been taken from the author\u27s opening paragraphs

    Qualitative Approach of the Scrutiny in Educational Psychology

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    It was difficult for the interpretive opposing approach to fight the previous exclusive current with its ideographic approach to the study of a now subjective reality, which was consolidated and applied to practice with the transformative intention of the complementary socio-critical approach2, and through some of the qualitative methods: a) in the first approach, through the participant or non-participant ethnographic observation, instrumental, institutional, individual or collective study cases that provide understanding rather than previous description; b) in the second one, through the research-action or research based on the design that reverts the situation studied to free and improve it.El enfoque funcionalista tradicional en la representación y abordaje de la Ciencia ha dejado una férrea herencia metodológica de investigación de objetos y fenómenos objetivos con intención puramente nomotética de describirlos avanzado hacia principios y leyes generales, atemporales y universales, bajo métodos cuantitativos. Métodos cuantitativos tanto experimentales y/o cuasiexperimentales, de evaluación pretest-postest con un tratamiento intermedio, como no experimentales de tipo descriptivo, relacional, comparativo, predictivo, factorial y de meta-análisis, donde no existe manipulación o tratamiento por parte del investigador

    Psychological Flow Scale (PFS): Development and Preliminary Validation of a New Flow Instrument that Measures the Core Experience of Flow to Reflect Recent Conceptual Advancements

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    In this study, we sought to develop—and provide preliminary validity evidence for scores derived from—a new Psychological Flow Scale (PFS). We propose a parsimonious model of three core dimensions of flow, reflecting the findings from a recent scoping review that synthesised flow research across scientific disciplines. The validation process for the PFS addressed recent conceptual criticisms of flow science regarding construct validity, theoretical compatibility, relational ambiguity, and definitional inconsistency. An initial review and analysis of the many flow measurements that exist found that these instruments either assess one, some, or none of the three core-dimensions of flow; often measuring similar dimensions that may bear resemblance to one of the three-dimensions but differ in dimensional meaning. PFS item development involved a phase of theoretical scrutiny, review of existing instruments, item generation, and expert review of items. Subsequently, 936 participants were recruited for scale development purposes, which included sample testing, exploratory factor analysis, and confirmatory factor analysis. This factor analytic process showed evidence for three distinguishable dimensions ‘under’ a single general or higher-order factor (i.e., global flow). With respect to external aspects of validity, flow scores correlated positively with perceptions of competence, self-rated performance, autotelic personality, and negatively with anxiety and stress scores. In conclusion, we present preliminary evidence for the theoretical and operational suitability of the PFS to assess the flow state across scientific disciplines and activity domains that be useful for experimental research and enable comparative flow research in the future

    Psychological flow training: Feasibility and preliminary efficacy of an educational intervention on flow

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    Despite there being an increasing number of applied flow studies across scientific disciplines, there exists no consistent or broadly applicable intervention to promote flow experiences. This study provides a detailed account of a new educational flow training program developed following recent advancements in the flow literature that have provided a more parsimonious understanding of flow experiences and antecedents. Guided by CONSORT guidelines for feasibility trials, we conducted a single-group, non-randomized feasibility trial of an educational flow training program (N = 26). We assessed participant retention, perceptions about and experiences of the program, perceptions about the flow education training, and preliminary assessments of flow as an outcome. Results broadly supported program feasibility, and participants reported positive experiences in, and perceptions of, program components. In terms of preliminary efficacy, we observed evidence of noteworthy change pre-to-post-program in flow (d = 0.84), performance (d = 0.81), competence (d = 0.96), well-being (d = 0.68), intrinsic motivation (d = 0.47), interest (d = 0.72), choice (d = 0.38), stress (d = -1.08), ability to handle stress (d = 0.74), and anxiety (d = − 0.86). These results provide preliminary evidence that it may be possible to ‘train’ flow in line with recent perspectives on a core three-dimensional flow experience (and antecedents). The study has developed a research foundation for flow intervention “curriculum” and quality standards, and for measuring results. It offers a foundation for the implementation of a larger-scale program

    Turbulent small-scale dynamo action in solar surface simulations

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    We demonstrate that a magneto-convection simulation incorporating essential physical processes governing solar surface convection exhibits turbulent small-scale dynamo action. By presenting a derivation of the energy balance equation and transfer functions for compressible magnetohydrodynamics (MHD), we quantify the source of magnetic energy on a scale-by-scale basis. We rule out the two alternative mechanisms for the generation of small-scale magnetic field in the simulations: the tangling of magnetic field lines associated with the turbulent cascade and Alfvenization of small-scale velocity fluctuations ("turbulent induction"). Instead, we find the dominant source of small-scale magnetic energy is stretching by inertial-range fluid motions of small-scale magnetic field lines against the magnetic tension force to produce (against Ohmic dissipation) more small-scale magnetic field. The scales involved become smaller with increasing Reynolds number, which identifies the dynamo as a small-scale turbulent dynamo.Comment: accepted by Ap

    The influence of surface morphology and wettability on the inflammatory response against poly(L-lactic acid): A semi-quantitative study with monoclonal antibodies

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    In this study, the influence of surface morphology and wettability of both degradable and nondegradable polymer films on the inflammatory response after subcutaneous implantation in the rat was investigated. Degradable nonporous, porous, and combi (porous with a nonporous layer on one side) poly(L-lactic acid) (PLLA) films and nondegradable polytetrafluoroethylene (PTFE) and (porous) expanded PTFE (e-PTFE) were used. Contact angles measurements indicate that PLLA is more hydrophillic than PTFE. Assessment of the inflammatory response was performed after various periods of implantation (up till 180 days), with both conventional light microscopy and immunohistochemistry using monoclonal antibodies (mAbs). The inflammatory response observed initially can largely be considered as part of the wound healing reaction, and up till day 40 the inflammatory response against PLLA was minimally more intense than against PTFE (porous as well as nonporous). From day 40 on, the PLLA films provoke a more intense inflammatory response as compared to the PTFE films. Both porous PLLA and the porous side of the combi PLLA film provoke a more intense inflammatory response than nonporous PLLA and the nonporous side of the combi PLLA film, respectively. In general, PTFE and e-PTFE films provoke an inflammatory response which is minimally more intense than the one provoked by the sham operation. Almost no ingrowth of tissue was observed in the porous e-PTFE films. In contrast, there was abundant tissue ingrowth in and an inflammatory response against porous PLLA. It can be concluded that biodegradable PLLA films provoke a more intense inflammatory response than nondegradable PTFE films. Also, porosity enhances the inflammatory response. However, porosity enhances the inflammatory response only when the wettability of a biomaterial permits cellular ingrowth

    In Silico Reconstitution of Listeria Propulsion Exhibits Nano-Saltation

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    To understand how the actin-polymerization-mediated movements in cells emerge from myriad individual protein–protein interactions, we developed a computational model of Listeria monocytogenes propulsion that explicitly simulates a large number of monomer-scale biochemical and mechanical interactions. The literature on actin networks and L. monocytogenes motility provides the foundation for a realistic mathematical/computer simulation, because most of the key rate constants governing actin network dynamics have been measured. We use a cluster of 80 Linux processors and our own suite of simulation and analysis software to characterize salient features of bacterial motion. Our “in silico reconstitution” produces qualitatively realistic bacterial motion with regard to speed and persistence of motion and actin tail morphology. The model also produces smaller scale emergent behavior; we demonstrate how the observed nano-saltatory motion of L. monocytogenes, in which runs punctuate pauses, can emerge from a cooperative binding and breaking of attachments between actin filaments and the bacterium. We describe our modeling methodology in detail, as it is likely to be useful for understanding any subcellular system in which the dynamics of many simple interactions lead to complex emergent behavior, e.g., lamellipodia and filopodia extension, cellular organization, and cytokinesis

    Saturation and time dependence of geodynamo models

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    In this study we address the question under which conditions a saturated velocity field stemming from geodynamo simulations leads to an exponential growth of the magnetic field in a corresponding kinematic calculation. We perform global self-consistent geodynamo simulations and calculate the evolution of a kinematically advanced tracer field. The self-consistent velocity field enters the induction equation in each time step, but the tracer field does not contribute to the Lorentz force. This experiment has been performed by Cattaneo & Tobias (2009) and is closely related to the test field method by Schrinner et al. (2005, 2007). We find two dynamo regimes in which the tracer field either grows exponentially or approaches a state aligned with the actual self-consistent magnetic field after an initial transition period. Both regimes can be distinguished by the Rossby number and coincide with the dipolar and multipolar dynamo regimes identified by Christensen & Aubert (2006). Dipolar dynamos with low Rossby number are kinematically stable whereas the tracer field grows exponentially in the multipolar dynamo regime. This difference in the saturation process for dynamos in both regimes comes along with differences in their time variability. Within our sample of 20 models, solely kinematically unstable dynamos show dipole reversals and large excursions. The complicated time behaviour of these dynamos presumably relates to the alternating growth of several competing dynamo modes. On the other hand, dynamos in the low Rossby number regime exhibit a rather simple time dependence and their saturation merely results in a fluctuation of the fundamental dynamo mode about its critical state.Comment: 6 pages, 8 figure

    Stellar dynamo driven wind braking instead of disc coupling

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    Star-disc coupling is considered in numerical models where the stellar field is not an imposed perfect dipole, but instead a more irregular self-adjusting dynamo-generated field. Using axisymmetric simulations of the hydromagnetic mean-field equations, it is shown that the resulting stellar field configuration is more complex, but significantly better suited for driving a stellar wind. In agreement with recent findings by a number of people, star-disc coupling is less efficient in braking the star than previously thought. Moreover, stellar wind braking becomes equally important. In contrast to a perfect stellar dipole field, dynamo-generated stellar fields favor field-aligned accretion with considerably higher velocity at low latitudes, where the field is weaker and originating in the disc. Accretion is no longer nearly periodic (as it is in the case of a stellar dipole), but it is more irregular and episodic.Comment: 19 pages, 15 figures, some errors corrected, Astron. Nach. (submitted). For higher quality images, see http://www.nordita.dk/~brandenb/papers/stellardyn

    Controlling weapons circulation in a postcolonial militarised world

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    What are the politics of, and prospects for, contemporary weapons control? Human rights and humanitarian activists and scholars celebrate the gains made in the UN Arms Trade Treaty as a step towards greater human security. Critics counter that the treaty represents an accommodation with global militarism. Taking the tensions between arms transfer control and militarism as my starting point, I argue that the negotiating process and eventual treaty text demonstrate competing modes of militarism. Expressed in terms of sovereignty, political economy, or human security, all three modes are underpinned by ongoing imperial relations: racial, gendered and classed relations of asymmetry and hierarchy that persist despite formal sovereign equality. This means human security is a form of militarism rather than the antithesis of it. Drawing on primary sources from negotiations and participant observation with actors involved in the campaign for the ATT, the argument challenges the idea that human security has scored a victory over militarism. It also complicates our understanding of the nature of the accommodation with it, demonstrating the transformation as well as entrenchment of contemporary militarism. The argument reframes the challenges for controlling weapons circulation, placing the necessity for feminist, postcolonial anti-militarist critique front and centre
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