Institutional structures and processes for environmental planning and management of the peri-urban interface

Strategies are needed which deal not only with urban impacts but also with the transitional nature of activities in the zone, once urban impacts are felt. And there are strategies for rural activities to exploit their proximity to towns and cities. Yet these strategies must be matched to the limited capacities of the institutions available for formulating and implementing them if they are to be effective. Alternatively, institutions can be given new capacities or new relationships

Asymptotic Safety, Asymptotic Darkness, and the hoop conjecture in the extreme UV

Assuming the hoop conjecture in classical general relativity and quantum mechanics, any observer who attempts to perform an experiment in an arbitrarily small region will be stymied by the formation of a black hole within the spatial domain of the experiment. This behavior is often invoked in arguments for a fundamental minimum length. Extending a proof of the hoop conjecture for spherical symmetry to include higher curvature terms we investigate this minimum length argument when the gravitational couplings run with energy in the manner predicted by asymptotically safe gravity. We show that argument for the mandatory formation of a black hole within the domain of an experiment fails. Neither is there a proof that a black hole doesn't form. Instead, whether or not an observer can perform measurements in arbitrarily small regions depends on the specific numerical values of the couplings near the UV fixed point. We further argue that when an experiment is localized on a scale much smaller than the Planck length, at least one enshrouding horizon must form outside the domain of the experiment. This implies that while an observer may still be able to perform local experiments, communicating any information out to infinity is prevented by a large horizon surrounding it, and thus compatibility with general relativity can still be restored in the infrared limit.Comment: 9 pages, Matched Published Version with minor changes for clarity and emphasis of key point

Einstein-Aether Waves

Local Lorentz invariance violation can be realized by introducing extra tensor fields in the action that couple to matter. If the Lorentz violation is rotationally invariant in some frame, then it is characterized by an ``aether'', i.e. a unit timelike vector field. General covariance requires that the aether field be dynamical. In this paper we study the linearized theory of such an aether coupled to gravity and find the speeds and polarizations of all the wave modes in terms of the four constants appearing in the most general action at second order in derivatives. We find that in addition to the usual two transverse traceless metric modes, there are three coupled aether-metric modes.Comment: 5 pages; v2: Remarks added concerning gauge invariance of the waves and hyperbolicity of the equations. Essentially the version published in PR

Not very many options for the people who are working here Rural Housing Challenges Through the Lens of Two New England Communities

In this brief, authors Jessica Carson and Marybeth Mattingly use interview and focus group data to describe some of the ways that restricted rural housing stock affects working families in two rural New England counties, and explore solutions proposed by rural residents and experts to make housing affordable. They report that many rural places are challenged by unaffordable and inadequate housing. In rural communities with scenic amenities, the draw of second-home owners and retirees restricts housing options for local working families. Land use regulations to preserve the scenery in these places limits options for developing affordable housing. The federal safety net provides good options for many rural residents struggling with housing costs, but the programs are often insufficiently funded to reach all residents in need. Policy makers and practitioners should consider innovative ways to improve and leverage existing housing stock in order to expand affordable, high-quality options for local working families

The strong Feller property for singular stochastic PDEs

We show that the Markov semigroups generated by a large class of singular stochastic PDEs satisfy the strong Feller property. These include for example the KPZ equation and the dynamical $\Phi^4_3$ model. As a corollary, we prove that the Brownian bridge measure is the unique invariant measure for the KPZ equation with periodic boundary conditions