3,135 research outputs found
Steel Tarrifs: A Shining Example of the Tenstion Between Politics and Economics in the United States
On the horns of a dilemma: experts as communicators for property-level flood risk adaptation measures
This paper investigates the role of flood risk experts in supporting homeowners to implement property-level flood risk adaption (PLFRA). Homeowners can reduce their flood risks by implementing PLFRA. However, oftentimes they need advice on what sort of and how to implement PLFRA. This means that tailored experts advice is necessary to inform homeowners on such measures. But experience shows that mere information is often insufficient to motivate homeowners to realize measures. This contribution explores the reasons for the ineffectiveness of expert advice by investigating how expert advice responds to homeowners’ rationalities. Based on a case study from Flanders, Belgium, this paper reveals how the relation between experts and homeowners differs related to different rationalities of homeowners. The paper uses Cultural Theory to discuss strategies on how experts, providing advice on property-level risk adaption, could move beyond engineering skills by also using risk communication skills in order to involve homeowners in flood risk governance
The undebated issue of justice: silent discourses in Dutch flood risk management
Flood risk for all types of flooding is projected to increase based on climate change projections and increases in damage potential. These challenges are likely to aggravate issues of justice in flood risk management (henceforth FRM). Based on a discursive-institutionalist perspective, this paper explores justice in Dutch FRM: how do institutions allocate the responsibilities and costs for FRM for different types of flooding? What are the underlying conceptions of justice? What are the future challenges with regard to climate change? The research revealed that a dichotomy is visible in the Dutch approach to FRM: despite an abundance of rules, regulations and resources spent, flood risk or its management, are only marginally discussed in terms of justice. Despite that the current institutional arrangement has material outcomes that treat particular groups of citizens differently, depending on the type of flooding they are prone to, area they live in (unembanked/embanked) or category of user (e.g. household, industry, farmer). The paper argues that the debate on justice will (re)emerge, since the differences in distributional outcomes are likely to become increasingly uneven as a result of increasing flood risk. The Netherlands should be prepared for this debate by generating the relevant facts and figures. An inclusive debate on the distribution of burdens of FRM could contribute to more effective and legitimate FRM
Role of the heat shock transcription factor, Hsf1, in a major fungal pathogen that is obligately associated with warm-blooded animals
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Chromospheric and coronal heating and jet acceleration due to reconnection driven by flux cancellation : I. At a three-dimensional current sheet
Funding: P.S. acknowledges support by the ERC synergy grant 'The Whole Sun'.Context. The recent discovery of much greater magnetic flux cancellation taking place at the photosphere than previously realised has led us in our previous works to suggest magnetic reconnection driven by flux cancellation as the cause of a wide range of dynamic phenomena, including jets of various kinds and solar atmospheric heating. Aims. Previously, the theory considered energy release at a two-dimensional current sheet. Here we develop the theory further by extending it to an axisymmetric current sheet in three dimensions without resorting to complex variable theory. Methods. We analytically study reconnection and treat the current sheet as a three-dimensional structure. We apply the theory to the cancellation of two fragments of equal but opposite flux that approach each another and are located in an overlying horizontal magnetic field. Results. The energy release occurs in two phases. During Phase 1, a separator is formed and reconnection is driven at it as it rises to a maximum height and then moves back down to the photosphere, heating the plasma and accelerating a plasma jet as it does so. During Phase 2 the fluxes cancel in the photosphere and accelerate a mixture of cool and hot plasma upwards.Publisher PDFPeer reviewe
A cancellation nanoflare model for solar chromospheric and coronal heating. III. 3D simulations and atmospheric response
This research has made use of NASA's Astrophysics Data System. This work was supported by computational time granted from the Greek Research and Technology Network (GRNET) in the National HPC facility ARIS. P.S. acknowledges support by the ERC synergy grant "The Whole Sun."Inspired by recent observations suggesting that photospheric magnetic flux cancellation occurs much more frequently than previously thought, we analytically estimated the energy released from reconnection driven by photospheric flux cancellation, and propose that it can act as a mechanism for chromospheric and coronal heating. Using two-dimensional simulations we validated the analytical estimates and studied the resulting atmospheric response. In the present work, we set up 3D resistive MHD simulations of two canceling polarities in a stratified atmosphere with a horizontal external field to further validate and improve upon the analytical estimates. The computational evaluation of the parameters associated with the energy release are in good qualitative agreement with the analytical estimates. The computational Poynting energy flux into the current sheet is in good qualitative agreement with the analytical estimates, after correcting the analytical expression to better account for the horizontal extent of the current sheet. The atmospheric response to the cancellation is the formation of hot ejections, cool ejections, or a combination of both hot and cool ejections, which can appear with a time difference and/or be spatially offset, depending on the properties of the canceling region and the resulting height of the reconnection. Therefore, during the cancellation, a wide spectrum of ejections can be formed, which can account for the variety of multi-thermal ejections associated with Ellerman bombs, UV bursts, and IRIS bombs, and also other ejections associated with small-scale canceling regions and spicules.Publisher PDFPeer reviewe
Locating current sheets in the solar corona
Current sheets are essential for energy dissipation in the solar corona, in
particular by enabling magnetic reconnection. Unfortunately, sufficiently thin
current sheets cannot be resolved observationally and the theory of their
formation is an unresolved issue as well. We consider two predictors of coronal
current concentrations, both based on geometrical or even topological
properties of a force free coronal magnetic field. First, there are
separatrices related to magnetic nulls. Through separatrices the magnetic
connectivity changes discontinuously. Coronal magnetic nulls are, however, very
rare. At second, inspired by the concept of generalized magnetic reconnection
without nulls, quasi-separatrix layers (QSL) were suggested. Through QSL the
magnetic connectivity changes continuously, though strongly. The strength of
the connectivity change can be quantified by measuring the squashing of the
flux tubes which connect the magnetically conjugated photospheres.
We verify the QSL and separatrix concepts by comparing the sites of magnetic
nulls and enhanced squashing with the location of current concentrations in the
corona. Due to the known difficulties of their direct observation we simulated
the coronal current sheets by numerically calculating the response of the
corona to energy input from the photosphere heating a simultaneously observed
EUV Bright Point. We did not find coronal current sheets not at the
separatrices but at several QSL locations. The reason is that although the
geometrical properties of force free extrapolated magnetic fields can indeed,
hint at possible current concentrations, a necessary condition for current
sheet formation is the local energy input into the corona
Infinite barbarians
This paper discusses an infinite regress that looms behind a certain kind of historical explanation. The movement of one barbarian group is often explained by the movement of others, but those movements in turn call for an explanation. While their explanation can again be the movement of yet another group of barbarians, if this sort of explanation does not stop somewhere we are left with an infinite regress of barbarians. While that regress would be vicious, it cannot be accommodated by several general views about what viciousness in infinite regresses amounts to. This example is additional evidence that we should prefer a pluralist approach to infinite regresses
Sensation Seeking and Perceived Need for Structure Moderate Soldiers’ Well-Being Before and After Operational Deployment
This study examined associations between sensation seeking and perceived need for structure, and changes in reported well-being among deployed soldiers. Participants (n = 167) were assessed before and after a six-month deployment to south Afghanistan. Results indicated that although well-being declined in the soldier sample as a whole following deployment, the degree of decrease was significantly different among soldiers with different personality profiles. Differences were moderated by soldiers’ level of sensation seeking and perceived need for structure. Results are discussed in terms of a person-environment fit theory in the context of preparation and rehabilitation of deployed military personnel
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