The Spin Period of EX Hydrae

We show that the spin period of the white dwarf in the magnetic CV EX Hydrae represents an equilibrium state in which the corotation radius is comparable with the distance from the white dwarf to the inner Lagrange point. We also show that a continuum of spin equilibria exists at which Pspin is significantly longer than \sim 0.1 Porb. Most systems occupying these equilibrium states should have orbital periods below the CV period gap, as observed.Comment: MNRAS, accepte

"Building" exact confidence nets

Confidence nets, that is, collections of confidence intervals that fill out the parameter space and whose exact parameter coverage can be computed, are familiar in nonparametric statistics. Here, the distributional assumptions are based on invariance under the action of a finite reflection group. Exact confidence nets are exhibited for a single parameter, based on the root system of the group. The main result is a formula for the generating function of the coverage interval probabilities. The proof makes use of the theory of "buildings" and the Chevalley factorization theorem for the length distribution on Cayley graphs of finite reflection groups.Comment: 20 pages. To appear in Bernoull

Outbursts of Young Stellar Objects

We argue that the outbursts of the FU Orionis stars occur on timescales which are much longer than expected from the standard disc instability model with \alpha_{c} \gtrsim 10^{-3}. The outburst, recurrence, and rise times are consistent with the idea that the accretion disc in these objects is truncated at a radius R_{i} \sim 40 \rsun. In agreement with a number of previous authors we suggest that the inner regions of the accretion discs in FU Ori objects are evacuated by the action of a magnetic propeller anchored on the central star. We develop an analytic solution for the steady state structure of an accretion disc in the presence of a central magnetic torque, and present numerical calculations to follow its time evolution. These calculations confirm that a recurrence time that is consistent with observations can be obtained by selecting appropriate values for viscosity and magnetic field strength.Comment: 13 pages, 7 figures, accepted by MNRA

The steady-state structure of accretion discs in central magnetic fields

We develop a new analytic solution for the steady-state structure of a thin accretion disc under the influence of a magnetic field that is anchored to the central star. The solution takes a form similar to that of Shakura and Sunyaev and tends to their solution as the magnetic moment of the star tends to zero. As well as the Kramer's law case, we obtain a solution for a general opacity. The effects of varying the mass transfer rate, spin period and magnetic field of the star as well as the opacity model applied to the disc are explored for a range of objects. The solution depends on the position of the magnetic truncation radius. We propose a new approach for the identification of the truncation radius and present an analytic expression for its position.Comment: 11 pages, 7 figures, accepted by MNRA

The Accretion Flows and Evolution of Magnetic Cataclysmic Variables

We have used a model of magnetic accretion to investigate the accretion flows of magnetic cataclysmic variables. Numerical simulations demonstrate that four types of flow are possible: discs, streams, rings and propellers. The fundamental observable determining the accretion flow, for a given mass ratio, is the spin-to-orbital period ratio of the system. If IPs are accreting at their equilibrium spin rates, then for a mass ratio of 0.5, those with Pspin/Porb < 0.1 will be disc-like, those with 0.1 < Pspin/Porb < 0.6 will be stream-like, and those with Pspin/Porb ~ 0.6 will be ring-like. The spin to orbital period ratio at which the systems transition between these flow types increases as the mass ratio of the stellar components decreases. For the first time we present evolutionary tracks of mCVs which allow investigation of how their accretion flow changes with time. As systems evolve to shorter orbital periods and smaller mass ratios, in order to maintain spin equilibrium, their spin-to-orbital period ratio will generally increase. As a result, the relative occurrence of ring-like flows will increase, and the occurrence of disc-like flows will decrease, at short orbital periods. The growing number of systems observed at high spin-to-orbital period ratios with orbital periods below 2h, and the observational evidence for ring-like accretion in EX Hya, are fully consistent with this picture.Comment: Accepted for publication in ApJ. 6 figures - included here at low resolutio

On the accretion mode of the intermediate polar V1025 Centauri

The long white-dwarf spin periods in the magnetic cataclysmic variables EX Hya and V1025 Cen imply that if the systems possess accretion discs then they cannot be in equilibrium. It has been suggested that instead they are discless accretors in which the spin-up torques resulting from accretion are balanced by the ejection of part of the accretion flow back towards the secondary. We present phase-resolved spectroscopy of V1025 Cen aimed at deducing the nature of the accretion flow, and compare this with simulations of a discless accretor. We find that both the conventional disc-fed model and the discless-accretor model have strengths and weaknesses, and that further work is needed before we can decide which applies to V1025 Cen.Comment: 9 pages, 8 figures, To appear in MNRAS, includes low-res figures to reduce siz

Beat sociology: Ethnographic journeys in event spaces

Beat Sociology: Ethnographic Journeys in Event Spaces proposes a new theory and methodology for Sociology to better investigate and describe the social experiences of individuals. I call this new set of theories and methodologies Beat Sociology--I have developed this project utilizing the work of Beat writers (Kerouac, Ginsberg and Burroughs), as well as social theorists (particularly Walter Benjamin and C. Wright Mills). Drawing from critical theory, postmodernism and ethnography, I develop three central \u27themes\u27 that help facilitate my project: identity, space, and migrancy. Through auto-ethnography I explore three types of Las Vegas spaces: event spaces, casino spaces and Fremont Street. Las Vegas has gained sociological, architectural and philosophic relevance in recent years, and through Beat Sociology I explore these spaces as well as explore contemporary sociological issues--spatiality, identity, migrancy, technologies of control, epiphanies, events and objects

Leadership-Skilled Women Teachers Who Choose the Classroom over Administration: Career Choice or Career Constraint?

Twelve women were interviewed regarding their choice to remain in the classroom, their perceptions of the principal-ship, and the barriers for women who might be interested in school administration. Two presentations of the data are given, with the first addressing explicit reasons and the second using a post-modem feminist framework

Review of \u3ci\u3eEnvironmental City: People, Place, Politics, and the Meaning of Modern Austin. \u3c/i\u3eBy William Scott Swearingen, Jr.

William Scott Swearingen, lr.\u27s Environmental City is a social history of how a place like Red Bud Isle and the larger city surrounding it could come to exist. Swearingen opens with the founding of Austin, and takes the reader through the ideals shaping its modern era: the battle between the twin paradigms of growth and green. At its heart, the book tells the story of the success of Austin\u27s green campaign: how place was created, fought for, and won. Not all battles were victories, but Swearingen points to key moments, and unpacks the slow process of institutionalizing broad environmental concepts into concrete municipal policies. He identifies the particular moments (e.g., protests, votes, and elections) and ideas (e.g., The Five Minute Walk ) that set this history in motion. Swearingen does the yeoman\u27s work of identifying just how one of the key aspects of Austin\u27s culture came to be. Although lacking in comparison, Environmental City is a good book for reading about how tensions play out in a city other than Los Angeles, Chicago, or New York