AX J0049.4-7323 - a close look at a neutron star interacting with a circumstellar disk

Detailed evidence on the system AX J0049.4-7323 is presented here to show how the passage of the neutron star in the binary system disrupts the circumstellar disk of the mass donor Be star. A similar effect is noted in three other Be/X-ray binary systems. Together the observational data should provide valuable tools for modelling these complex interactions.Comment: 4 pages, accepted for publication in MNRA

Seafood Trade, Fisheries Management and Human Livelihoods

In 1976 global exports for fish and fisheries products was approximately $8 billion. In 2000, global exports exceeded$55 billion. The period between 1985 and 1995 witnessed the tripling of global fisheries exports. This represents more than half of total value of global fisheries production. Developing countries began to increase their share of this total during the 1990s and now account for more than half of global exports. In 2000 the net trade value (exports minus imports) for developing country seafood exports exceeded $18 billion. Taken at face value these statistics suggest that the monetary benefits of fisheries trade have increased in the wake of EEZ extension with developing countries benefiting the most. These statistics fail to reflect some important costs, however. Such costs include subsidies to the fishing industry and a variety of social and environmental externalities associated with changes in fishing activity. They also tell us little about how both costs and benefits resulting from fisheries trade our distributed among a variety of affected stakeholders within fisheries and the communities that depend upon them. In particular, the trends depicted above have been criticized for adverse impacts on small-scale fishing communities and their historical institutional arrangements. This paper will explore the interplay between seafood trade, fisheries management and human livelihoods. The paper will argue that economic structure of a given fisheries sector, the political organization of its industry, and the institutional arrangements that govern it all play important roles in determining the size and distribution of costs and benefits associated with the expansion of seafood trade

Searching the Footprint of WIMPZILLAs

We constrain mass, lifetime and contribution of a very slowly decaying Ultra Heavy Dark Matter (UHDM) by simulating the cosmological evolution of its remnants. Most of interactions which participate in energy dissipation are included in the numerical solution of the Boltzmann equation. Cross-sections are calculated either analytically or by using PYTHIA Monte Carlo program. This paper describes in detail our simulation. To show the importance of the distribution of matter in constraining WIMPZILLA characteristics, we consider two extreme cases: a homogeneous universe, and a local halo with uniform distribution. We show that in a homogeneous universe, the decay of UHDM with a mass \sim 10^15 GeV and a lifetime \sim a few times \tau_0 the age of the Universe, can not explain the flux of observed Ultra High Energy Cosmic Rays (UHECRs). This shows the importance of nearby sources, notably galactic halo. In a uniform clump with an over-density of \sim 200 extended to 100 kpc or more, the lifetime must be \sim 10 - 100 \tau_0 or the contribution in the DM must be proportionally smaller. We also compare our calculation with observed gamma-rays at E \sim 10^11 eV by EGRET and CASA-MIA limit at E \sim 10^15 eV. They are compatible with a UHDM with relatively short lifetime.Comment: 27 pages, 9 figures. New results with better energy resolution close to GZK cutoff. Text slightly modifie

The Minimal CFL-Nuclear Interface

At nuclear matter density, electrically neutral strongly interacting matter in weak equilibrium is made of neutrons, protons and electrons. At sufficiently high density, such matter is made of up, down and strange quarks in the color-flavor locked phase, with no electrons. As a function of increasing density (or, perhaps, increasing depth in a compact star) other phases may intervene between these two phases which are guaranteed to be present. The simplest possibility, however, is a single first order phase transition between CFL and nuclear matter. Such a transition, in space, could take place either through a mixed phase region or at a single sharp interface with electron-free CFL and electron-rich nuclear matter in stable contact. Here we construct a model for such an interface. It is characterized by a region of separated charge, similar to an inversion layer at a metal-insulator boundary. On the CFL side, the charged boundary layer is dominated by a condensate of negative kaons. We then consider the energetics of the mixed phase alternative. We find that the mixed phase will occur only if the nuclear-CFL surface tension is significantly smaller than dimensional analysis would indicate.Comment: 30 pages, 7 figure

The Interrelationships Between REIT Capital Structure and Investment

We investigate whether Real Estate Investment Trust (REIT) managers actively manipulate performance measures in spite of the strict regulation under the REIT regime. We provide empirical evidence that is consistent with this hypothesis. Specifically, manipulation strategies may rely on the opportunistic use of leverage. However, manipulation does not appear to be uniform across REIT sectors and seems to become more common as the level of competition in the underlying property sector increases. We employ a set of commonly used traditional performance measures and a recently developed manipulation-proof measure (MPPM, Goetzmann, Ingersoll, Spiegel, and Welch (2007)) to evaluate the performance of 147 REITs from seven different property sectors over the period 1991-2009. Our findings suggest that the existing REIT regulation may fail to mitigate a substantial agency conflict and that investors can benefit from evaluating return information carefully in order to avoid potentially manipulative funds

The eclipsing LMC star OGLE05155332--6925581: a clue for Double Periodic Variables

We investigate the nature of OGLE05155332-6925581, one of the brightest members of the enigmatic group of Double Periodic Variables (DPVs) recently found in the Magellanic Clouds. The modeling of archival orbital light curves (LCs), along with the analysis of the radial velocities suggest that this object is a semi--detached binary with the less massive star transferring matter to the more massive and less evolved star, in an Algol--like configuration. We find evidence for additional orbital variability and H$\alpha$ emission, likely caused by an accretion disc around the primary star. As in the case of $\beta Lyr$ the circumprimary disc seems to be more luminous than the primary, but we do not detect orbital period changes. We find that the LC follows a loop in the color--magnitude diagram during the long cycle; the system is redder when brighter and the rising phase is bluer than during decline. Infrared excess is also present. The source of the long--term periodicity is not eclipsed, indicating its circumbinary origin. Strong asymmetries, discrete absorption components (DACs) and a $\gamma$ shift are new and essential observational properties in the infrared H I lines. The DACs strength and RV follow a saw--teeth pattern during the orbital cycle. We suggest that the system experiences supercycles of mass outflow feeding a circumbinary disc. Mass exchange and mass loss could produce comparable but opposite effects in the orbital period on a long time scale, resulting in a quasi--constancy of this parameter.Comment: submitted to MNRA

Development of a new generation of optical slope measuring profiler

A collaboration, including all DOE synchrotron labs, industrial vendors of x-ray optics, and with active participation of the HBZ-BESSY-II optics group has been established to work together on a new slope measuring profiler -- the optical slope measuring system (OSMS). The slope measurement accuracy of the instrument is expected to be<50 nrad for the current and future metrology of x-ray optics for the next generation of light sources. The goals were to solidify a design that meets the needs of mirror specifications and also be affordable; and to create a common specification for fabrication of a multi-functional translation/scanning (MFTS) system for the OSMS. This was accomplished by two collaborative meetings at the ALS (March 26, 2010) and at the APS (May 6, 2010)

Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe

Observations of the high-redshift Universe with the 21 cm hyperfine line of neutral hydrogen promise to open an entirely new window onto the early phases of cosmic structure formation. Here we review the physics of the 21 cm transition, focusing on processes relevant at high redshifts, and describe the insights to be gained from such observations. These include measuring the matter power spectrum at z~50, observing the formation of the cosmic web and the first luminous sources, and mapping the reionization of the intergalactic medium. The epoch of reionization is of particular interest, because large HII regions will seed substantial fluctuations in the 21 cm background. We also discuss the experimental challenges involved in detecting this signal, with an emphasis on the Galactic and extragalactic foregrounds. These increase rapidly toward low frequencies and are especially severe for the highest redshift applications. Assuming that these difficulties can be overcome, the redshifted 21 cm line will offer unique insight into the high-redshift Universe, complementing other probes but providing the only direct, three-dimensional view of structure formation from z~200 to z~6.Comment: extended review accepted by Physics Reports, 207 pages, 44 figures (some low resolution); version with high resolution figures available at http://pantheon.yale.edu/~srf28/21cm/index.htm; minor changes to match published versio

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available