Lorentz contraction, geometry and range in antiproton-proton annihilation into two pions

We present a geometric interpretation of the so-called annihilation range in reactions of the type $\bar pp \to$ {\em two light mesons} based upon Lorentz effects in the highly relativistic final states ($\gamma=E_{\mathrm{cm}}/2mc^2\simeq 6.8-8.0$). Lorentz-boosted meson wave functions, within the framework of the constituent quark model, result in a richer angular dependence of the annihilation amplitudes and thus in higher partial wave contributions ($J>1$) than usually obtained. This approach sheds some light on what could be a "{\em short}" annihilation range and how it is influenced by the angular distribution of the final states.Comment: LEAP05 (Bonn/Juelich) proceedings, 5 page

Relativistic effects and angular dependence in the reaction antiproton-proton -> pi^- pi^+

We present a new fit to the LEAR data on antiproton-proton -> pi^- pi^+ differential cross sections and analyzing powers motivated by relativistic considerations. Within a quark model describing this annihilation we argue, since the pions are highly energetic, that relativistic effects cannot be neglected. The intrinsic pion wave functions are Lorentz transformed to the center of mass frame. This change in quark geometry gives rise to additional angular dependence in the transition operators and results in a relative enhancement of higher J \ge 2 partial wave amplitudes. The fit to the data is improved significantly.Comment: Revtex 4, 7 pages, 5 figures. Continuation and results of a previous paper: nucl-th/040305

Mineralocorticoid receptor blockade during a rat's first violent encounter inhibits its subsequent propensity for violence.

In individuals naive to serious conflict in an unfamiliar environment, violence has long-lasting effects on subsequent aggressive behavior. This effect of the stressful experience of a first violent conflict occurs in victims as well as offenders. The authors study in the male rat as offender the role of a rapid corticosterone signal mediated by brain mineralocorticoid receptors (MR) in adjusting the threshold of aggressive responses. For this purpose, the authors have applied electrical stimulation of the brain's aggression circuit via the hypothalamic attack area or HAA. Using this paradigm, they found that in inexperienced rats, retesting of the animals on subsequent days facilitated aggression. Hypothalamic attack thresholds decreased to about 50% of their initial level. However, blocking the MR once with the mineralocorticoid antagonist spironolactone, during the very first evoked attacks, permanently prevented attack facilitation in subsequent conflicts in that same environment. The MR-mediated effect blocked by the antagonist occurred within an hour following the start of the first aggression tests only. A later MR blockade was not effective. These findings suggest that the corticosterone stress response during a very first serious conflict initializes an enhanced propensity for violent aggression through the brain MR

A relativistic treatment of pion wave functions in the annihilation antiproton-proton -> pi^-pi^+

Quark model intrinsic wave functions of highly energetic pions in the reaction \bar pp->\pi^-\pi^+ are subjected to a relativistic treatment. The annihilation is described in a constituent quark model with A2 and R2 flavor-flux topology and the annihilated quark-antiquark pairs are in 3P_0 and 3S_1 states. We study the effects of pure Lorentz transformations on the antiquark and quark spatial wave functions and their respective spinors in the pion. The modified quark geometry of the pion has considerable impact on the angular dependence of the annihilation mechanisms.Comment: 10 pages in revtex format, 3 figure

A Trip to the Co-op: The Production, Consumption and Salvation of CanadianWilderness

In this paper, I analyze Mountain Equipment Co-op (MEC) catalogues from1987-2007, in order to examine how they produce wilderness, invite consumption andoffer up their products as a means of salvation for wilderness and for MEC members.My analysis of the MEC catalogues draws connections between how wilderness, andindeed the nation, is understood through the production of a conscientiouseco-consumer. Wilderness is understood as pivotal to Canadian national identity and has beenused to demarcate those imagined within and outside of the nation. I draw attentionto shifts in wilderness discourse in order to see how wilderness has been employedfor economic, political and social uses. I show that images and texts in the MECcatalogues call on familiar wilderness tropes thus making a consumer subject appearboth logical and desirable for its members and for the nation.Dans cet article, nous analysons les catalogues de 1987-2007 de la MountainEquipment Co-op (MEC) afin d’examiner la façon dont elle exalte le milieusauvage, invite à la consommation et offre ses produits comme un moyen de sauver lanature ainsi que ses membres. Nous visons à établir des liens entre, d’unepart, la compréhension de la nature et, par conséquent, de la nation et,d’autre part, la production d’une conscience d’écoconsommateur. La nature qui est considérée comme étant le pivot de l’identité nationalecanadienne est utilisée pour distinguer l’image identitaire véhiculée au seinde la nation de celle véhiculée à l’étranger. Nous prêtons une attentionparticulière à l’évolution du discours sur la nature afin d’étudierl’exploitation de la nature à des fins économiques, politiques et sociales.Nous montrons que les images et les textes dans les catalogues de la MECtransmettent un milieu sauvage familier et rendent, par conséquent, la consommationtant logique que souhaitable pour ses membres et pour la nation

What’s in a Name? Compelled Identification Statutes and Violations of the Fourth and Fifth Amendments

Article published in the Michigan State University School of Law Student Scholarship Collection