1,425 research outputs found

    Tracing the magnetic field of IRDC G028.23-00.19 using NIR polarimetry

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    The importance of the magnetic (B) field in the formation of infrared dark clouds (IRDCs) and massive stars is an ongoing topic of investigation. We studied the plane-of-sky B field for one IRDC, G028.23-00.19, to understand the interaction between the field and the cloud. We used near-IR background starlight polarimetry to probe the B field and performed several observational tests to assess the field importance. The polarimetric data, taken with the Mimir instrument, consisted of H-band and K-band observations, totaling 17,160 stellar measurements. We traced the plane-of-sky B-field morphology with respect to the sky-projected cloud elongation. We also found the relationship between the estimated B-field strength and gas volume density, and we computed estimates of the normalized mass-to-magnetic flux ratio. The B-field orientation with respect to the cloud did not show a preferred alignment, but it did exhibit a large-scale pattern. The plane-of-sky B-field strengths ranged from 10 to 165 ÎĽG, and the B-field strength dependence on density followed a power law with an index consistent with 2/3. The mass-to-magnetic flux ratio also increased as a function of density. The relative orientations and relationship between the B field and density imply that the B field was not dynamically important in the formation of the IRDC. The increase in mass-to-flux ratio as a function of density, though, indicates a dynamically important B field. Therefore, it is unclear whether the B field influenced the formation of G28.23. However, it is likely that the presence of the IRDC changed the local B-field morphology.We thank J. Montgomery, T. Hogge, and I. Stephens for constructive discussions on the analysis. We are grateful to R. Crutcher for permission to include his Zeeman data. This research was conducted in part using the Mimir instrument, jointly developed at Boston University and Lowell Observatory and supported by NASA, NSF, and the W.M. Keck Foundation. This research made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology (Caltech), under contract with NASA. This publication made use of data products from the Two Micron All Sky Survey, which was a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/Caltech, funded by NASA and NSF. This work is based in part on data obtained as part of the UKIRT Infrared Deep Sky Survey. The ATLAS-GAL project is a collaboration between the Max-PlanckGesellschaft, the European Southern Observatory (ESO), and the Universidad de Chile. It includes projects E-181.C-0885, E-078.F-9040(A), M-079.C-9501(A), M-081.C-9501(A), and Chilean data. This publication makes use of molecular line data from the Boston University-FCRAO Galactic Ring Survey (GRS). The GRS is a joint project of Boston University and Five College Radio Astronomy Observatory, funded by the National Science Foundation under grants AST-9800334, 0098562, 0100793, 0228993, and. 0507657. A.E.G. acknowledges support from FONDECYT 3150570. This work was supported under NSF grants AST 09-07790 and 14-12269 and NASA grant NNX15AE51G to Boston University. We thank the anonymous referee for valuable feedback, which improved the quality of this work. (NASA; NSF; W.M. Keck Foundation; E-181.C-0885 - Max-Planck-Gesellschaft; E-078.F-9040(A) - Max-Planck-Gesellschaft; M-079.C-9501(A) - Max-Planck-Gesellschaft; M-081.C-9501(A) - Max-Planck-Gesellschaft; E-181.C-0885 - European Southern Observatory (ESO); E-078.F-9040(A) - European Southern Observatory (ESO); M-079.C-9501(A) - European Southern Observatory (ESO); M-081.C-9501(A) - European Southern Observatory (ESO); E-181.C-0885 - Universidad de Chile; E-078.F-9040(A) - Universidad de Chile; M-079.C-9501(A) - Universidad de Chile; M-081.C-9501(A) - Universidad de Chile; AST-9800334 - National Science Foundation; 0098562 - National Science Foundation; 0100793 - National Science Foundation; 0228993 - National Science Foundation; 0507657 - National Science Foundation; 3150570 - FONDECYT; AST 09-07790 - NSF; 14-12269 - NSF; NNX15AE51G - NASA

    Temporary urbanisms as policy alternatives to enhance health and well-being in the post-pandemic city

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    Purpose of Review: While there has been extensive discussion on the various forms of temporary uses in urban settings, little is known on the ways in which temporary and health urbanisms connect. Now, a turning point has been reached regarding the interactions between health and the built environment and the contributions made by urban planning and other built environment disciplines. In the context of the post-pandemic city, there is a need to develop a health-led temporary urbanism agenda than can be implemented in various settings both in the Global South and North. Recent Findings: Health-led temporary urbanism requires a reinterrogation of current models of urban development including designing multifunctional spaces in urban environments that provide sites for temporary urbanism-related activities. A healthy city is an adaptable city and one that provides opportunities for citizen-led interventions intended to enhance well-being by blending the temporary with the permanent and the planned with the improvised. Summary: Health-led temporary urbanism contributes to the call for more trans- and inter-disciplinary discussions allowing to more thoroughly link urban planning and development with health

    Enhancing quality of life through the lens of green spaces: A systematic review approach

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    Improving citizens’ quality of life is a stated priority of many governments in both the global north and south.  However, efforts to achieve this often focus on socio-economic measures, with limited attention to the contributions of environmental variables such as green spaces.  This paper sought to bridge this knowledge gap by tracing the linkages between green spaces and quality of life, and how these connections can inform policy development in order to assist governments to achieve positive outcomes for quality of life.  The paper took a theoretical approach by utilising the systematic review method.  In all, 452 publications were included in this review, and rigorous content analysis was employed to retrieve relevant data.  Green spaces were found to provide various social, economic, and environmental benefits, which in turn improve physical, psychological, emotional, social, and material wellbeing of individuals and thus enhance quality of life.  It is therefore strongly recommended that conservation of green spaces should be integrated into national health, environmental and socio-economic policies in order to promote effective utilisation of green spaces to enhance citizens’ overall quality of life

    Natural hazard management and sustainable development: a questionable link

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    This article examines the nature of the possible link between natural hazards and sustainable development through a study of the area to the south of Grenoble in the French Alps, a zone subject to two major natural hazards: the extensive landslide known as the "Séchilienne Ruins" and flooding from the Romanche and Drac rivers. More specifically, the study analyzes the assumed transition from the management of natural hazards to the sustainable management of an area subject to natural hazards and is divided into three stages. Thus the link between natural hazards and sustainability is considered as: 1) an association that is entirely relative, 2) one that is logical but limited in the field, 3) one that is above all indirect. The interactions identified between risk and sustainability, in legislative as well as ideal and operational terms, are found to be complex and not necessarily explicit. They depend in particular on the juxtaposition of multiple territorial scales or spatial boundaries (national to local) that bring into conflict the different strategies of the actors involved – from decision-makers to technical specialists.Cet article questionne la nature du lien envisageable entre risque naturel et développement durable à travers l’étude du territoire du sud grenoblois, soumis notamment à deux aléas naturels majeurs : le mouvement de terrain de grande ampleur dit des « Ruines de Séchilienne » et les probables crues de la Romanche et du Drac. Trois étapes structurent cette réflexion questionnant la transition supposée entre une gestion des risques naturels et une gestion durable des territoires soumis aux risques naturels : une association toute relative, un lien logique mais limité sur le terrain, une relation surtout indirecte. Les interactions identifiées, en termes législatifs mais aussi idéels et opérationnels, entre risque et durabilité se révèlent ainsi complexes et ne sont pas forcément explicites ; elles dépendent en particulier de multiples échelles territoriales (nationales à locales), confrontant alors pour l’essentiel des stratégies d’acteurs – porteurs des décisions ou du savoir technique – distinctes

    The creative economy in a context of transition: A review of the mechanisms of micro-resilience

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    This paper assesses the coping mechanisms of creative SMEs in the context of recent economic downturns. It argues that such industries develop various forms of micro-resilience anchored in three main dimensions: production, space and people. By using the case of Digbeth and the Custard Factory as a lens to focus the discussion, it posits the argument that micro-resilience rests upon competitive advantages, including corporate reputation and the capacity of those industries to be flexible, adaptable and entrepreneurial. It also notes that space and locality, as intangible resources, act as leverages to provide an adequate working environment, allowing financial viability and clustering. Finally, it points out that creative workers and their informal networks favour a range of tactics allowing micro-resiliency

    Gestion des risques naturels et prise en compte du développement durable : un lien équivoque. Le cas du sud grenoblois

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    Cet article questionne la nature du lien envisageable entre risque naturel et développement durable à travers l’étude du territoire du sud grenoblois, soumis notamment à deux aléas naturels majeurs : le mouvement de terrain de grande ampleur dit des « Ruines de Séchilienne » et les probables crues de la Romanche et du Drac. Trois étapes structurent cette réflexion questionnant la transition supposée entre une gestion des risques naturels et une gestion durable des territoires soumis aux risques naturels : une association toute relative, un lien logique mais limité sur le terrain, une relation surtout indirecte. Les interactions identifiées, en termes législatifs mais aussi idéels et opérationnels, entre risque et durabilité se révèlent ainsi complexes et ne sont pas forcément explicites ; elles dépendent en particulier de multiples échelles territoriales (nationales à locales), confrontant alors pour l’essentiel des stratégies d’acteurs – porteurs des décisions ou du savoir technique – distinctes
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