The Effect of Adding Features on Product Attractiveness: the Role of Product Perceived Congruity

This paper investigates the effect of adding more features on product evaluation. We argue that product evaluation as the number of features increases depends on the congruity of the features added with the product. We show that adding features leads to increased product attractiveness if these features are congruent with the product, but not if these features are moderately or extremely incongruent. However, the manipulation of two factors, task involvement and temporal construal, has been shown to make product evaluation increase as more moderately (but not extremely) incongruent features are added to the product

WISE Circumstellar Disks in the Young Sco-Cen Association

We present an analysis of the WISE photometric data for 829 stars in the Sco-Cen OB2 association, using the latest high-mass membership probabilities. We detect infrared excesses associated with 135 BAF-type stars, 99 of which are secure Sco-Cen members. There is a clear increase in excess fraction with membership probability, which can be fitted linearly. We infer that 41+-5% of Sco-Cen OB2 BAF stars to have excesses, while the field star excess fraction is consistent with zero. This is the first time that the probability of non-membership has been used in the calculation of excess fractions for young stars. We do not observe any significant change in excess fraction between the three subgroups. Within our sample, we have observed that B-type association members have a significantly smaller excess fraction than A and F-type association members.Comment: 5 Pages, 3 figure, 4 tables. Complete table 1 included. Accepted to MNRAS Letter

Rapid dynamical mass segregation and properties of fractal star clusters

We investigate the evolution of young star clusters using N-body simulations. We confirm that subvirial and fractal-structured clusters will dynamically mass segregate on a short timescale (within 0.5 Myr). We adopt a modified minimum-spanning-tree (MST) method to measure the degree of mass segregation, demonstrating that the stars escaping from a cluster's potential are important for the temporal dependence of mass segregation in the cluster. The form of the initial velocity distribution will also affect the degree of mass segregation. If it depends on radius, the outer parts of the cluster would expand without undergoing collapse. In velocity space, we find 'inverse mass segregation,' which indicates that massive stars have higher velocity dispersions than their lower-mass counterparts.Comment: 13 pages and 6 figures based on 14 .eps file

Evidence for Evolution Among Primordial Disks in the 5 Myr Old Upper Scorpius OB Association

Moderate-resolution, near-infrared spectra between 0.8 and 5.2 microns were obtained for 12 late-type (K0-M3) disk-bearing members of the ~5 Myr old Upper Scorpius OB association using SpeX on the NASA Infrared Telescope Facility. For most sources, continuum excess emission first becomes apparent between ~2.2 and 4.5 microns and is consistent with that produced by single-temperature blackbodies having characteristic temperatures ranging from ~500 to 1300 K. The near-infrared spectra for 5 of 12 Upper Scorpius sources exhibit Pa-gamma, Pa-beta and Br-gamma emission, indicators of disk accretion. Using a correlation between Pa-beta and Br-gamma emission line luminosity and accretion luminosity, mass accretion rates (Mdot) are derived for these sources that range from Mdot = 3.5 X 10^{-10} to 1.5 X 10^{-8} MSun per yr. Merging the SpeX observations with Spitzer Space Telescope mid-infrared (5.4-37.0 micron) spectroscopy and 24 and 70 micron broadband photometry, the observed spectral energy distributions are compared with those predicted by two-dimensional, radiative transfer accretion disk models. Of the 9 Upper Scorpius sources examined in this analysis, 3 exhibit spectral energy distributions that are most consistent with models having inner disk radii that substantially exceed their respective dust sublimation radii. The remaining Upper Scorpius members possess spectral energy distributions that either show significant dispersion among predicted inner disk radii or are best described by models having inner disk rims coincident with the dust sublimation radius.Comment: 35 pages, 5 figures, accepted for publication in the Astronomical Journa

The OMII Software Distribution

This paper describes the work carried out at the Open Middleware Infrastructure Institute (OMII) and the key elements of the OMII software distribution that have been developed in collaboration with members of the Managed Programme Initiative. The main objective of the OMII is to preserve and consolidate the achievements of the UK e-Science Programme by collecting, maintaining and improving the software modules that form the key components of a generic Grid middleware. Recently, the activity at Southampton has been extended beyond 2009 through a new project, OMII-UK, that forms a partnership that now includes the OGSA-DAI activities at Edinburgh and the myGrid project at Manchester

Systematic detection of magnetic fields in massive, late-type supergiants

We report the systematic detection of magnetic fields in massive (M > 5 M$_\odot$) late-type supergiants, using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii Telescope. Our observations reveal detectable Stokes V Zeeman signatures in Least-Squares Deconvolved mean line profiles in one-third of the observed sample of more than 30 stars. The signatures are sometimes complex, revealing multiple reversals across the line. The corresponding longitudinal magnetic field is seldom detected, although our longitudinal field error bars are typically 0.3 G ($1\sigma$). These characteristics suggest topologically complex magnetic fields, presumably generated by dynamo action. The Stokes V signatures of some targets show clear time variability, indicating either rotational modulation or intrinsic evolution of the magnetic field. We also observe a weak correlation between the unsigned longitudinal magnetic field and the CaII K core emission equivalent width of the active G2Iab supergiant $\beta$~Dra and the G8Ib supergiant $\epsilon$~Gem.Comment: 8 pages, 1 table, 6 figures, accepted for publication in MNRA

Dirac Gauginos, Negative Supertraces and Gauge Mediation

In an attempt to maximize General Gauge Mediated parameter space, I propose simple models in which gauginos and scalars are generated from disconnected mechanisms. In my models Dirac gauginos are generated through the supersoft mechanism, while independent R-symmetric scalar masses are generated through operators involving non-zero messenger supertrace. I propose several new methods for generating negative messenger supertraces which result in viable positive mass squareds for MSSM scalars. The resultant spectra are novel, compressed and may contain light fermionic SM adjoint fields.Comment: 16 pages 3 figure