Avoiding deontic explosion by contextually restricting aggregation

In this paper, we present an adaptive logic for deontic conflicts, called P2.1(r), that is based on Goble's logic SDLaPe-a bimodal extension of Goble's logic P that invalidates aggregation for all prima facie obligations. The logic P2.1(r) has several advantages with respect to SDLaPe. For consistent sets of obligations it yields the same results as Standard Deontic Logic and for inconsistent sets of obligations, it validates aggregation "as much as possible". It thus leads to a richer consequence set than SDLaPe. The logic P2.1(r) avoids Goble's criticisms against other non-adjunctive systems of deontic logic. Moreover, it can handle all the 'toy examples' from the literature as well as more complex ones

Introduction to \u3ci\u3eThe Endangered Species Act at Thirty, Volume 2\u3c/i\u3e

More than thirty years after its passage, the Endangered Species Act (ESA) of 1973 continues to be a corners tone of U.S. biodiversity policy and among our most powerful environmentallaws. The ESA set the nation\u27s biodiversity conservation policy on a path that emphasized species-based conservation and triggered action only when a species faced imminent extinction. However, promoting recovery has proven more challenging than the original designers of the law anticipated. The number of listed species has mushroomed from 78 in 1973 to 1,267 in 2005, while in that time only 13 species have recovered sufficiently to be removed from the list (Scott et al. 2006). As described in The Endangered Species Act at 30: Renewing the Conservation Promise, the act has proven remarkably durable in spite of nearly continuous political assaults and legal and scientific challenges (Goble et al. 2006). The contributing authors to that volume describe a variety of factors responsible for the act\u27s endurance. Public support for species conservation has remained strong, especially for high-visibility species such as the bald eagle (Haliaeetus leucocephalus) and grizzly bear (Ursus arctos horribilis) but also for less-charismatic taxa. The act has been championed by environmental groups in part for its power to control development, a role supported by a majority of the American public (Czech and Krausman 1997). Reforms have also been important to the act\u27s continuance. In particular, implementation has evolved over the years from an absolute prohibition on take of endangered species to a more flexible permitting system, thereby defusing potentially explosive conservation conflicts on private lands. The act has also catalyzed administrative and legal reforms at all levels of government that have led to positive changes in natural resource management in rural areas and in urban open space planning

Impact of Short-Range Scattering on the Metallic Transport of Strongly Correlated 2D Holes in GaAs Quantum Wells

Understanding the non-monotonic behavior in the temperature dependent resistance, R(T), of strongly correlated two-dimensional (2D) carriers in clean semiconductors has been a central issue in the studies of 2D metallic states and metal-insulator-transitions. We have studied the transport of high mobility 2D holes in 20nm wide GaAs quantum wells (QWs) with varying short-range disorder strength by changing the Al fraction x in the Al_xGa_{1-x}As barrier. Via varying the short range interface roughness and alloy scattering, it is observed that increasing x suppresses both the strength and characteristic temperature scale of the 2D metallicity, pointing to the distinct role of short-range versus long-range disorder in the 2D metallic transport in this correlated 2D hole system with interaction parameter r_s~ 20.Comment: accepted for publication in Phys Rev

Bose-Einstein condensation as symmetry breaking in compact curved spacetimes

We examine Bose-Einstein condensation as a form of symmetry breaking in the specific model of the Einstein static universe. We show that symmetry breaking never occursin the sense that the chemical potential $\mu$ never reaches its critical value.This leads us to some statements about spaces of finite volume in general. In an appendix we clarify the relationship between the standard statistical mechanical approaches and the field theory method using zeta functions.Comment: Revtex, 25 pages, 3 figures, uses EPSF.sty. To be published in Phys. Rev.

The elements of a computational infrastructure for social simulation

Applications of simulation modelling in social science domains are varied and increasingly widespread. The effective deployment of simulation models depends on access to diverse datasets, the use of analysis capabilities, the ability to visualize model outcomes and to capture, share and re-use simulations as evidence in research and policy-making. We describe three applications of e-social science that promote social simulation modelling, data management and visualization. An example is outlined in which the three components are brought together in a transport planning context. We discuss opportunities and benefits for the combination of these and other components into an e-infrastructure for social simulation and review recent progress towards the establishment of such an infrastructure

Photon-Photon Scattering, Pion Polarizability and Chiral Symmetry

Recent attempts to detect the pion polarizability via analysis of $\gamma\gamma\rightarrow\pi\pi$ measurements are examined. The connection between calculations based on dispersion relations and on chiral perturbation theory is established by matching the low energy chiral amplitude with that given by a full dispersive treatment. Using the values for the polarizability required by chiral symmetry, predicted and experimental cross sections are shown to be in agreement.Comment: 21 pages(+10 figures available on request), LATEX, UMHEP-38

Dimensionality effects in restricted bosonic and fermionic systems

The phenomenon of Bose-like condensation, the continuous change of the dimensionality of the particle distribution as a consequence of freezing out of one or more degrees of freedom in the low particle density limit, is investigated theoretically in the case of closed systems of massive bosons and fermions, described by general single-particle hamiltonians. This phenomenon is similar for both types of particles and, for some energy spectra, exhibits features specific to multiple-step Bose-Einstein condensation, for instance the appearance of maxima in the specific heat. In the case of fermions, as the particle density increases, another phenomenon is also observed. For certain types of single particle hamiltonians, the specific heat is approaching asymptotically a divergent behavior at zero temperature, as the Fermi energy $\epsilon_{\rm F}$ is converging towards any value from an infinite discrete set of energies: ${\epsilon_i}_{i\ge 1}$. If $\epsilon_{\rm F}=\epsilon_i$, for any i, the specific heat is divergent at T=0 just in infinite systems, whereas for any finite system the specific heat approaches zero at low enough temperatures. The results are particularized for particles trapped inside parallelepipedic boxes and harmonic potentials. PACS numbers: 05.30.Ch, 64.90.+b, 05.30.Fk, 05.30.JpComment: 7 pages, 3 figures (included

Archiving Software Surrogates on the Web for Future Reference

Software has long been established as an essential aspect of the scientific process in mathematics and other disciplines. However, reliably referencing software in scientific publications is still challenging for various reasons. A crucial factor is that software dynamics with temporal versions or states are difficult to capture over time. We propose to archive and reference surrogates instead, which can be found on the Web and reflect the actual software to a remarkable extent. Our study shows that about a half of the webpages of software are already archived with almost all of them including some kind of documentation.Comment: TPDL 2016, Hannover, German