Amorphization induced by pressure: results for zeolites and general implications

We report an {\sl ab initio} study of pressure-induced amorphization (PIA) in zeolites, which are model systems for this phenomenon. We confirm the occurrence of low-density amorphous phases like the one reported by Greaves {\sl et al.} [Science {\bf 308}, 1299 (2005)], which preserves the crystalline topology and might constitute a new type of glass. The role of the zeolite composition regarding PIA is explained. Our results support the correctness of existing models for the basic PIA mechanim, but suggest that energetic, rather than kinetic, factors determine the irreversibility of the transition.Comment: 4 pages with 3 figures embedded. More information at http://www.icmab.es/dmmis/leem/jorg

Shades of Grey: Ethical Dilemmas

No abstract available

Astrophysical limitations to the identification of dark matter: indirect neutrino signals vis-a-vis direct detection recoil rates

A convincing identification of dark matter (DM) particles can probably be achieved only through a combined analysis of different detections strategies, which provides an effective way of removing degeneracies in the parameter space of DM models. In practice, however, this program is made complicated by the fact that different strategies depend on different physical quantities, or on the same quantities but in a different way, making the treatment of systematic errors rather tricky. We discuss here the uncertainties on the recoil rate in direct detection experiments and on the muon rate induced by neutrinos from dark matter annihilations in the Sun, and we show that, contrarily to the local DM density or overall cross section scale, irreducible astrophysical uncertainties affect the two rates in a different fashion, therefore limiting our ability to reconstruct the parameters of the dark matter particle. By varying within their respective errors astrophysical parameters such as the escape velocity and the velocity dispersion of dark matter particles, we show that the uncertainty on the relative strength of the neutrino and direct-detection signal is as large as a factor of two for typical values of the parameters, but can be even larger in some circumstances.Comment: 12 pages, 3 figures. Improved presentation and Fig.3; clarifications, references and an appendix added; conclusions unchanged. Matches version published in PR

Advertising agency engagement and regulatory empowerment in the world of new media

This paper examines how new media has impacted advertiser behaviours in relation to controversial advertising. This research seeks to explore the extent of advertiser engagement and regulatory empowerment in a new media environment, where an advertiser can show offensive advertising online via new media despite a ban by the self regulatory body in relation to traditional media. Specifically, we conduct ten interviews with members of the advertising industry to develop an understanding of this engagement and empowerment. Findings suggest that advertisers are very aware that new media creates an opportunity for engagement, however,feedback is interpreted subjectively to rationalise continued dissemination of offensive advertising messages and therein advertisers are empowered

Bending the Rules of Evidence

The evidence rules have well-established, standard textual meanings—meanings that evidence professors teach their law students every year. Yet, despite the rules’ clarity, courts misapply them across a wide array of cases: Judges allow past acts to bypass the propensity prohibition, squeeze hearsay into facially inapplicable exceptions, and poke holes in supposedly ironclad privileges. And that’s just the beginning. The evidence literature sees these misapplications as mistakes by inept trial judges. This Article takes a very different view. These “mistakes” are often not mistakes at all, but rather instances in which courts are intentionally bending the rules of evidence. Codified evidentiary rules are typically rigid, leaving little room for judicial discretion. When unforgiving rules require exclusion of evidence that seems essential to a case, courts face a Hobson’s choice: Stay faithful to the rules, or instead preserve the integrity of the factfinding process. Frequently, courts have found a third way, claiming nominal fidelity to a rule while contorting it to ensure the evidence’s admissibility. This Article identifies and explores this bending of the rules of evidence. After tracing rule bending across many evidence doctrines, the Article explores the normative roots of the problem. Codification has ossified evidence law, effectively driving judges underground in the search for solutions to their evidentiary dilemmas. Rather than trying to suppress rule bending, we advocate legitimizing it. Specifically, the Article proposes a residual exception that would enable trial courts to admit essential evidence in carefully defined circumstances. Such an exception would bring rule bending out of the shadows and into the light with benefits to transparency, legitimacy, and accountability. And perhaps most importantly, it will reestablish trial courts as a partner in the development of evidence law

A Simple Family of Analytical Trumpet Slices of the Schwarzschild Spacetime

We describe a simple family of analytical coordinate systems for the Schwarzschild spacetime. The coordinates penetrate the horizon smoothly and are spatially isotropic. Spatial slices of constant coordinate time $t$ feature a trumpet geometry with an asymptotically cylindrical end inside the horizon at a prescribed areal radius $R_0$ (with $0<R_{0}\leq M$) that serves as the free parameter for the family. The slices also have an asymptotically flat end at spatial infinity. In the limit $R_{0}=0$ the spatial slices lose their trumpet geometry and become flat -- in this limit, our coordinates reduce to Painlev\'e-Gullstrand coordinates.Comment: 7 pages, 3 figure

Bending the Rules of Evidence

The evidence rules have well-established, standard textual meanings—meanings that evidence professors teach their law students every year. Yet, despite the rules’ clarity, courts misapply them across a wide array of cases: Judges allow past acts to bypass the propensity prohibition, squeeze hearsay into facially inapplicable exceptions, and poke holes in supposedly ironclad privileges. And that’s just the beginning.The evidence literature sees these misapplications as mistakes by inept trial judges. This Article takes a very different view. These “mistakes” are often not mistakes at all, but rather instances in which courts are intentionally bending the rules of evidence. Codified evidentiary rules are typically rigid, leaving little room for judicial discretion. When unforgiving rules require exclusion of evidence that seems essential to a case, courts face a Hobson\u27s choice: stay faithful to the rules, or instead preserve the integrity of the factfinding process. Frequently, courts have found a third way, claiming nominal fidelity to a rule while contorting it to ensure the evidence’s admissibility.This Article identifies and explores this bending of the rules of evidence. After tracing rule bending across many evidence doctrines, the Article explores the normative roots of the problem. Codification has ossified evidence law, effectively driving judges underground in the search for solutions to their evidentiary dilemmas. Rather than trying to suppress rule bending, we advocate legitimizing it. Specifically, the Article proposes a residual exception that would enable trial courts to admit essential evidence in carefully defined circumstances. Such an exception would bring rule bending out of the shadows and into the light with benefits to transparency, legitimacy, and accountability. And perhaps most importantly, it will re-establish trial courts as a partner in the development of evidence law

WIMP astronomy and particle physics with liquid-noble and cryogenic direct-detection experiments

Once weakly-interacting massive particles (WIMPs) are unambiguously detected in direct-detection experiments, the challenge will be to determine what one may infer from the data. Here, I examine the prospects for reconstructing the local speed distribution of WIMPs in addition to WIMP particle-physics properties (mass, cross sections) from next-generation cryogenic and liquid-noble direct-detection experiments. I find that the common method of fixing the form of the velocity distribution when estimating constraints on WIMP mass and cross sections means losing out on the information on the speed distribution contained in the data and may lead to biases in the inferred values of the particle-physics parameters. I show that using a more general, empirical form of the speed distribution can lead to good constraints on the speed distribution. Moreover, one can use Bayesian model-selection criteria to determine if a theoretically-inspired functional form for the speed distribution (such as a Maxwell-Boltzmann distribution) fits better than an empirical model. The shape of the degeneracy between WIMP mass and cross sections and their offset from the true values of those parameters depends on the hypothesis for the speed distribution, which has significant implications for consistency checks between direct-detection and collider data. In addition, I find that the uncertainties on theoretical parameters depends sensitively on the upper end of the energy range used for WIMP searches. Better constraints on the WIMP particle-physics parameters and speed distribution are obtained if the WIMP search is extended to higher energy (~ 1 MeV).Comment: 25 pages, 27 figures, matches published versio