358 research outputs found
Shaping flood risk governance through science-policy interfaces: insights from England, France and The Netherlands
In the face of increasing threats from flooding, there are growing calls to strengthen and improve arrangements of flood risk governance (FRG). This endeavour requires an appreciation of the multitude of factors stabilising and driving governance dynamics. So-called catalyst flood events, policy champions and advocacy coalitions have tended to dominate this study to date, whilst the potential role played by Science Policy Interfaces (SPIs) has been somewhat neglected and often approached in a reductionist and fragmented way. This paper addresses this gap by drawing from in-depth policy analysis and stakeholder interviews conducted within England, France and the Netherlands under the auspices of the EU-FP7 STAR-FLOOD project. The analysis reveals four prominent ways in which SPIs shape FRG, by i) facilitating the diversification of Flood Risk Management (FRM) strategies; ii) increasing their connectivity, iii) facilitating a decentralisation of FRM and iv) fostering inter-country learning. It identifies different roles of specific interfaces (structures) and interfacing mechanisms (processes) in shaping governance dynamics. This way, the analysis reveals various ‘entry points’ through which SPIs can steer FRG, either along existing pathways, or towards new and potentially transformative change. The study shows that SPIs are a hitherto underexposed factor explaining dynamics in flood risk governance which merits additional systematic empirical study
Emergent states in heavy electron materials
We obtain the conditions necessary for the emergence of various low
temperature ordered states (local moment antiferromagnetism, unconventional
superconductivity, quantum criticality, and Landau Fermi liquid behavior) in
Kondo lattice materials by extending the two-fluid phenomenological theory of
heavy electron behavior to incorporate the concept of hybridization
effectiveness. We use this expanded framework to present a new phase digram and
consistent physical explanation and quantitative description of measured
emergent behaviors such as the pressure variation of the onset of local moment
antiferromagnetic ordering at T_N, the magnitude of the ordered moment, the
growth of superconductivity within that ordered state, the location of a
quantum critical point, and of a delocalization line in the
pressure/temperature phase diagram at which local moments have disappeared and
the heavy electron Fermi surface has grown to its maximum size. We apply our
model to CeRhIn_5 and a number of other heavy electron materials and find good
agreement with experiment.Comment: 20 pages, 8 figures, 1 tabl
Recurrent governance challenges in the implementation and alignment of flood risk management strategies: a review
In Europe increasing flood risks challenge societies to diversify their Flood Risk Management Strategies (FRMSs). Such a diversification implies that actors not only focus on flood defence, but also and simultaneously on flood risk prevention, mitigation, preparation and recovery. There is much literature on the implementation of specific strategies and measures as well as on flood risk governance more generally. What is lacking, though, is a clear overview of the complex set of governance challenges which may result from a diversification and alignment of FRM strategies. This paper aims to address this knowledge gap. It elaborates on potential processes and mechanisms for coordinating the activities and capacities of actors that are involved on different levels and in different sectors of flood risk governance, both concerning the implementation of individual strategies and the coordination of the overall set of strategies. It identifies eight overall coordination mechanisms that have proven to be useful in this respect
Polymers grafted to porous membranes
We study a single flexible chain molecule grafted to a membrane which has
pores of size slightly larger than the monomer size. On both sides of the
membrane there is the same solvent. When this solvent is good, i.e. when the
polymer is described by a self avoiding walk, it can fairly easily penetrate
the membrane, so that the average number of membrane crossings tends, for chain
length , to a positive constant. The average numbers of monomers on
either side of the membrane diverges in this limit, although their ratio
becomes infinite. For a poor solvent, in contrast, the entire polymer is
located, for large , on one side of the membrane. For good and for theta
solvents (ideal polymers) we find scaling laws, whose exponents can in the
latter case be easily understood from the behaviour of random walks.Comment: 4 pages, 6 figure
Shaping flood risk governance through science-policy interfaces: insights from England, France and The Netherlands
In the face of increasing threats from flooding, there are growing calls to strengthen and improve arrangements of flood risk governance (FRG). This endeavour requires an appreciation of the multitude of factors stabilising and driving governance dynamics. So-called catalyst flood events, policy champions and advocacy coalitions have tended to dominate this study to date, whilst the potential role played by Science Policy Interfaces (SPIs) has been somewhat neglected and often approached in a reductionist and fragmented way. This paper addresses this gap by drawing from in-depth policy analysis and stakeholder interviews conducted within England, France and the Netherlands under the auspices of the EU-FP7 STAR-FLOOD project. The analysis reveals four prominent ways in which SPIs shape FRG, by i) facilitating the diversification of Flood Risk Management (FRM) strategies; ii) increasing their connectivity, iii) facilitating a decentralisation of FRM and iv) fostering inter-country learning. It identifies different roles of specific interfaces (structures) and interfacing mechanisms (processes) in shaping governance dynamics. This way, the analysis reveals various ‘entry points’ through which SPIs can steer FRG, either along existing pathways, or towards new and potentially transformative change. The study shows that SPIs are a hitherto underexposed factor explaining dynamics in flood risk governance which merits additional systematic empirical study
Quantum corrections to the phase diagram of heavy-fermion superconductors
The competition between magnetism and Kondo effect is the main effect
determining the phase diagram of heavy fermion systems. It gives rise to a
quantum critical point which governs the low temperature properties of these
materials. However, experimental results made it clear that a fundamental
ingredient is missing in this description, namely superconductivity. In this
paper we make a step forward in the direction of incorporating
superconductivity and study the mutual effects of this phase and
antiferromagnetism in the phase diagram of heavy fermion metals. Our approach
is based on a Ginzburg-Landau theory describing superconductivity and
antiferromagnetism in a metal with quantum corrections taken into account
through an effective potential. The proximity of an antiferromagnetic
instability extends the region of superconductivity in the phase diagram and
drives this transition into a first order one. On the other hand
superconducting quantum fluctuations near a metallic antiferromagnetic quantum
critical point gives rise to a first order transition from a low moment to a
high moment state in the antiferromagnet. Antiferromagnetism and
superconductivity may both collapse at a quantum bicritical point whose
properties we calculate.Comment: 10 pages, 6 figure
Pressure-induced anomalous magnetism and unconventional superconductivity in CeRhIn5 : 115In-NQR Study under Pressure
We report In nuclear-quadrupole-resonance (NQR) measurements of the
pressure()-induced superconductor CeRhIn in the antiferromagnetic (AF)
and superconducting (SC) states. In the AF region, the internal field
at the In site is substantially reduced from kOe at P=0 to 0.39
kOe at GPa, while the N\'eel temperature slightly changes with
increasing . This suggests that either the size in the ordered moment
or the angle between the direction of and
the tetragonal axis is extrapolated to zero at GPa at
which a bulk SC transition is no longer emergent. In the SC state at
GPa, the nuclear spin-lattice relaxation rate has revealed a
dependence without the coherence peak just below , giving evidence
for the unconventional superconductivity. The dimensionality of the magnetic
flutuations in the normal state are also discussed.Comment: 8pages,4figures,submitted to Phys. Rev. B. Rapid
Toward more flood resilience: is a diversification of flood risk management strategies the way forward?
European countries face increasing flood risks due to urbanization, increase of exposure and damage potential, and the effects of climate change. In literature and in practice, it is argued that a diversification of strategies for flood risk management (FRM) - including flood risk prevention (through pro-active spatial planning), flood defense, flood risk mitigation, flood preparation and flood recovery - makes countries more flood resilient. While this thesis is plausible, it should still be empirically scrutinized. This paper aims to do this. Drawing on existing literature we operationalize the notion of "flood resilience" into three capacities: capacity to resist; capacity to absorb and recover; and capacity to transform and adapt. Based on findings from the EU FP7 project STAR-FLOOD, we explore the degree of diversification of FRM strategies and related flood risk governance arrangements at the national level in Belgium, England, France, The Netherlands, Poland and Sweden, as well as these countries' achievement in terms of the three capacities. We found that The Netherlands and to a lesser extent Belgium have a strong "capacity to resist", France a strong "capacity to absorb and recover" and especially England a high capacity to transform and adapt. Having a diverse portfolio of FRM strategies in place may be conducive to high achievements related to the capacities to absorb/recover and to transform and adapt. Hence, we conclude that diversification of FRM strategies contributes to resilience. However, the diversification thesis should be nuanced in the sense that there are different ways to be resilient. First, the three capacities imply different rationales and normative starting points for flood risk governance, the choice between which is inherently political. Second, we found trade-offs between the three capacities, e.g. being resistant seems to lower the possibility to be absorbent. Third, to explain countries' achievements in terms of resilience, the strategies' feasibility in specific physical circumstances and their fit in existing institutional contexts (appropriateness) as well as the establishment of links between strategies, through bridging mechanisms, have also been shown to be crucial factors. The paper provides much needed reflection on the implications of this diagnosis for governments, private parties and citizens who want to increase flood resilience
Exotic superconductivity in the coexistent phase of antiferromagnetism and superconductivity in CeCu2(Si0.98Ge0.02)2: A Cu-NQR study under hydrostatic pressure
We report a pressure () effect on CeCu(SiGe)
where an antiferromagnetic (AFM) order at 0.75 K coexists with
superconductivity below 0.4 K\@. At pressures exceeding
GPa, the AFM order is suppressed, which demonstrates that the sudden emergence
of AFM order due to the Ge doping is ascribed to the intrinsic lattice
expansion. The exotic superconductivity at GPa is found to evolve into
a typical heavy-fermion one with a line-node gap above GPa\@. We
highlight that the anomalous enhancement in nuclear spin-lattice relaxation
rate that follows a = const. behavior well below at =
0 GPa is characterized by the persistence of low-lying magnetic excitations,
which may be inherent to the coexistent state of antiferromagnetism and
superconductivity.Comment: 5 pages with 4 figures embedded in the text. To be published in J.
Phys. Soc. Jp
Incommensurate magnetic structure of CeRhIn5
The magnetic structure of the heavy fermion antiferromagnet CeRhIn5 is
determined using neutron diffraction. We find a magnetic wave vector
q_M=(1/2,1/2,0.297), which is temperature independent up to T_N=3.8K. A
staggered moment of 0.374(5) Bohr magneton at 1.4K, residing on the Ce ion,
spirals transversely along the c axis. The nearest neighbor moments on the
tetragonal basal plane are aligned antiferromagnetically.Comment: 4 pages, 4 figures There was an extra factor of 2 in Eq (2). This
affects the value of staggered moment. The correct staggered moment is
0.374(5) Bohr magneton at 1.4
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