Key dating features for timber-framed dwellings in Surrey

This article is made available through the Brunel Open Access Publishing Fund. Copyright @ The Vernacular Architecture Group 2013. MORE OpenChoice articles are open access and distributed under the terms of the Creative Commons Attribution License 3.0.The main component of the Surrey Dendrochronology Project is the accurate dating of 177 ‘dwellings’, nearly all by tree-ring analysis. The dates are used to establish date ranges for 52 ‘key features’, which cover many aspects of timber-framing from building type to details of carpentry. It is shown that changes of method and fashion were in many cases surprisingly rapid, almost abrupt in historical terms. Previous dating criteria for timber-framed dwellings in the county have been refined and new criteria introduced. Clusters of change from the 1440s and the 1540s are shown and some possible historical links suggested.The Heritage Lottery Fund, the Domestic Buildings Research Group (Surrey), the Surrey Archaeological Society and the historical societies of Charlwood, Farnham and Nutfield

A major outburst from the X-ray binary RX J0520.5-6932

We report on the analysis of 8 years of MAssive Compact Halo Objects (MACHO) data for the source RX J0520.5-6932. A regular period of 24.4 days has been confirmed, however this is manifest almost entirely in the red part of the spectrum. A major outburst, lasting approximately 200 days, was observed which increased the apparent brightness of the object by approximately 0.15 magnitudes without significantly altering its V-R colour index. This outburst was also seen in X-ray data. The evidence from this analysis points to the identification of this object as a Be/X-ray binary with a periodically variable circumstellar disk and a very early optical counterpart.Comment: Paper has been accepted by MNRA

Possible Cosmological Implications of the Quark-Hadron Phase Transition

We study the quark-hadron phase transition within an effective model of QCD, and find that in a reasonable range of the main parameters of the model, bodies with quark content between $10^{-2}$ and 10 solar masses can have been formed in the early universe. In addition, we show that a significant amount of entropy is released during the transition. This may imply the existence of a higher baryon number density than what is usually expected at temperatures above the QCD scale. The cosmological QCD transition may then provide a natural way for decreasing the high baryon asymmetry created by an Affleck-Dine like mechanism down to the value required by primordial nucleosynthesis.Comment: 19 pages, LaTeX, 5 Postscript figures included. Submitted to Journal of Physics

The binary period and outburst behaviour of the SMC X-ray binary pulsar system SXP504

A probable binary period has been detected in the optical counterpart to the X-ray source CXOU J005455.6-724510 = RX J0054.9-7245 = AXJ0054.8-7244 = SXP504 in the Small Magellanic Cloud. This source was detected by Chandra on 04 Jul 2002 and subsequently observed by XMM-Newton on 18 Dec 2003. The source is coincident with an Optical Gravitational Lensing (OGLE) object in the lightcurves of which several optical outburst peaks are visible at ~ 268 day intervals. Timing analysis shows a period of 268.6 +/- 0.1 days at > 99% significance. Archival Rossi X-ray Timing Explorer (RXTE) data for the 504s pulse-period has revealed detections which correspond closely with predicted or actual peaks in the optical data. The relationship between this orbital period and the pulse period of 504s is within the normal variance found in the Corbet diagram.Comment: Accepted by MNRAS. 1 LATEX page. 4 figure

Microlensing as a probe of the Galactic structure; 20 years of microlensing optical depth studies

Microlensing is now a very popular observational astronomical technique. The investigations accessible through this effect range from the dark matter problem to the search for extra-solar planets. In this review, the techniques to search for microlensing effects and to determine optical depths through the monitoring of large samples of stars will be described. The consequences of the published results on the knowledge of the Milky-Way structure and its dark matter component will be discussed. The difficulties and limitations of the ongoing programs and the perspectives of the microlensing optical depth technique as a probe of the Galaxy structure will also be detailed.Comment: Accepted for publication in General Relativity and Gravitation. General Relativity and Gravitation in press (2010) 0

Dynamical evolution of the Universe in the quark-hadron phase transition and possible nugget formation

We study the dynamics of first-order phase transition in the early Universe when it was $10-50 \mu s$ old with quarks and gluons condensing into hadrons. We look at how the Universe evolved through the phase transition in small as well as large super cooling scenario, specifically exploring the formation of quark nuggets and their possible survival. The nucleation of the hadron phase introduces new distance scales in the Universe, which we estimate along with the hadron fraction, temperature, nucleation time etc. It is of interest to explore whether there is a relic signature of this transition in the form of quark nuggets which might be identified with the recently observed dark objects in our galactic halo and account for the Dark Matter in the Universe at present.Comment: LaTeX file with four postscript figure

Curvature energy effects on strange quark matter nucleation at finite density

We consider the effects of the curvature energy term on thermal strange quark matter nucleation in dense neutron matter. Lower bounds on the temperature at which this process can take place are given and compared to those without the curvature term.Comment: PlainTex, 6 pp., IAG-USP Rep.5