ρ\rho meson broadening and dilepton production in heavy ion collisions

The modification of the width of the rho meson due to in-medium decays and collisions is evaluated. In high temperature and/or high density hadronic matter, the collision width is much larger than the one-loop decay width. The large width of the $\rho$ meson in matter seems to be consistent with some current interpretations of the $e^+ e^-$ mass spectra measured at the CERN/SPS.Comment: 4 pages, LaTeX, including 4 Postscript figures, to appear in Proc. of QM'99, Nucl. Phys.

Bag Formation in Quantum Hall Ferromagnets

Charged skyrmions or spin-textures in the quantum Hall ferromagnet at filling factor nu=1 are reinvestigated using the Hartree-Fock method in the lowest Landau level approximation. It is shown that the single Slater determinant with the minimum energy in the unit charge sector is always of the hedgehog form. It is observed that the magnetization vector's length deviates locally from unity, i.e. a bag is formed which accommodates the excess charge. In terms of a gradient expansion for extended spin-textures a novel O(3) type of effective action is presented, which takes bag formation into account.Comment: 13 pages, 3 figure

Off-shell effects in dilepton production from hot interacting mesons

The production of dielectrons in reactions involving a_1 mesons and pions is studied. We compare results obtained with different phenomenological Lagrangians that have been used in connection with hadronic matter and finite nuclei. We insist on the necessity for those interactions to satisfy known empirical properties of the strong interaction. Large off-shell effects in dielectron production are found and some consequences for the interpretation of heavy ion data are outlined. We also compare with results obtained using experimentally-extracted spectral functions.Comment: 14 pages, LaTeX2e, 2 figure

Between overt and covert research: concealment and disclosure in an ethnographic study of commercial hospitality

This article examines the ways in which problems of concealment emerged in an ethnographic study of a suburban bar and considers how disclosure of the research aims, the recruitment of informants, and elicitation of information was negotiated throughout the fieldwork. The case study demonstrates how the social context and the relationships with specific informants determined overtness or covertness in the research. It is argued that the existing literature on covert research and covert methods provides an inappropriate frame of reference with which to understand concealment in fieldwork. The article illustrates why concealment is sometimes necessary, and often unavoidable, and concludes that the criticisms leveled against covert methods should not stop the fieldworker from engaging in research that involves covertness

The Toxic Effects of Cigarette Additives. Philip Morris' Project Mix Reconsidered: An Analysis of Documents Released through Litigation

Stanton Glantz and colleagues analyzed previously secret tobacco industry documents and peer-reviewed published results of Philip Morris' Project MIX about research on cigarette additives, and show that this research on the use of cigarette additives cannot be taken at face value

Intermediate-mass dilepton spectra and the role of secondary hadronic processes in heavy-ion collisions

We carry out a study of intermediate-mass (between 1 and 2.5 GeV) dilepton spectra from hadronic interactions in heavy-ion collisions. The processes considered are $\pi\pi\to l{\bar l}$, $\pi\rho\to l{\bar l}$, $\pi a_1\to l{\bar l}$, $\pi\omega\to l{\bar l}$, $K{\bar K}\to l{\bar l}$, and $K{\bar K^*}+c.c \to l{\bar l}$. The elementary cross sections for those are obtained from chiral Lagrangians involving pseudoscalar, vector, and axial-vector mesons. The respective electromagnetic form factors are determined by fitting to experimental data for the reverse processes of $e^+e^-\to hadrons$. Based on this input we calculate cross sections and thermal dilepton emission rates and compare our results with those from other approaches. Finally we use these elementary cross sections with a relativistic transport model and calculate dilepton spectra in S+W collisions at SPS energies. The comparison of our results with experimental data from the HELIOS-3 collaboration indicates the importance of the secondary hadronic contributions to the intermediate-mass dilepton spectra.Comment: 25 pages, including 20 postscript figure

Reconceptualizing conservation

Early definitions of conservation focused largely on the end goals of protection or restoration of nature, and the various disciplinary domains that contribute to these ends. Conservation science and practice has evolved beyond being focused on just issues of scarcity and biodiversity decline. To better recognize the inherent links between human behaviour and conservation, “success” in conservation is now being defined in terms that include human rights and needs. We also know that who engages in conservation, and how, dictates the likelihood that conservation science will be embraced and applied to yield conservation gains. Here we present ideas for reconceptualizing conservation. We emphasize the HOW in an attempt to reorient and repurpose the term in ways that better reflect what contemporary conservation is or might aspire to be. To do so, we developed an acrostic using the letters in the term “CONSERVATION” with each serving as an adjective where C = co-produced, O = open, N = nimble, S = solutions-oriented, E = empowering, R = relational, V = values-based, A = actionable, T = transdisciplinary, I = inclusive, O = optimistic, and N = nurturing. For each adjective, we briefly describe our reasoning for its selection and describe how it contributes to our vision of conservation. By reconceptualizing conservation we have the potential to center how we do conservation in ways that are more likely to result in outcomes that benefit biodiversity while also being just, equitable, inclusive, and respectful of diverse rights holders, knowledge holders, and other actors. We hope that this acrostic will be widely adopted in training to help the next generation of conservation researchers and practitioners keep in mind what it will take to make their contributions effective and salient

The Return of The Prodigal Goldstone Boson

We propose that the mass of the $\eta^\prime$ meson is a particularly sensitive probe of the properties of finite energy density hadronic matter and quark gluon plasma. We argue that the mass of the $\eta^\prime$ excitation in hot and dense matter should be small, and therefore that the $\eta^\prime$ production cross section should be much increased relative to that for pp collisions. This may have observable consequences in dilepton and diphoton experiments.Comment: LaTeX, 15 pages; revised version to appear in Phys.Rev.