Librarians and the Attention Economy

With the advent of Web 2.0, libraries began not only developing innovative technology, but also new economic paradigms for library services. The present economic situation for libraries is unsustainable. Libraries, as a practical matter, cannot pay attention to everything, to every node, to every leaf on the tree of knowledge. Through creation of multiple points of interaction with users the result is an increase in the level of attention paid by the user compared to the static nature of Web 1.0 technologies which were mostly passive in regards to the users.Web 2.0 also represents an attempt to deal with the issue of scarcity of library resources by making the users partners with the librarians in the creation and development of content

Beyond the Brim of the Hat: Kinematics of Globular Clusters out to Large Radius in the Sombrero Galaxy

We have obtained radial velocity measurements for 51 new globular clusters around the Sombrero galaxy. These measurements were obtained using spectroscopic observations from the AAOmega spectrograph on the Anglo-Australian Telescope and the Hydra spectrograph at WIYN. Combined with our own past measurements and velocity measurements obtained from the literature we have constructed a large database of radial velocities that contains a total of 360 confirmed globular clusters. Previous studies' analyses of the kinematics and mass profile of the Sombrero globular cluster system have been constrained to the inner ~9' (~24 kpc or ~5 effective radii), but our new measurements have increased the radial coverage of the data, allowing us to determine the kinematic properties of M104 out to ~15' (~41 kpc or ~9 effective radii). We use our set of radial velocities to study the GC system kinematics and to determine the mass profile and V-band mass-to-light profile of the galaxy. We find that the V-band mass-to-light ratio increases from 4.5 at the center to a value of 20.9 at 41 kpc (~9 effective radii or 15'), which implies that the dark matter halo extends to the edge of our available data set. We compare our mass profile at 20 kpc (~4 effective radii or ~7.4') to the mass computed from x-ray data and find good agreement. We also use our data to look for rotation in the globular cluster system as a whole, as well as in the red and blue subpopulations. We find no evidence for significant rotation in any of these samples.Comment: Accepted for publication in the Astronomical Journal; 23 pages, 14 figures, and 2 table

Mistaken-for-Game Hunting Accidents: A Human Factors Review

Hunting accidents can have devastating consequences. One of the most common causes of hunting fatalities in this country, and others, are target identification failures—mistaking people for game. A golden rule in firearm safety is to identify your target beyond all doubt. Despite this message being constantly repeated, accidents are still occurring. Hunter education and awareness about high visibility clothing have reduced accident rates, but these statistics have since plateaued. Contrary to what most people think, the hunters committing these accidents are often experienced and considered to be safe and competent. Crucially, they often believe they have, 100%, correctly identified their target. Psychology and human factors can provide insight into how these situations might occur. When interpreting information, we rely heavily upon mental rules of thumb called heuristics. Heuristics operate outside of our conscious awareness and are utilised even more in stressful or emotionally charged situations. However, they can also make us susceptible to cognitive biases which may lead us astray—we underestimate the impact heuristics will have on our decisions. Attempts to manage heuristics and cognitive biases are often futile because we normally cannot detect them when they occur. Hunters are constantly told that they need to treat every sound or movement as human in an attempt to change their mind-set. However, given the difficulty in detecting cognitive biases, it is unlikely a hunter’s conscious management of heuristics would be consistently possible in the long term. Cognitive biases undoubtedly occur in hunting as in most activities we do. Analyses of accidents and anecdotal reports point to their involvement, as does research showing their involvement in other critical environments, including firearms operations in the military and the police. Given the impracticality of preventing heuristics and cognitive biases from affecting a hunter’s target identification, an additional approach is required. One method to prevent mistaken-for-game hunting accidents may involve the use of objective warning systems, such as those used to prevent friendly fire in the military. This white paper discusses four key cognitive biases which we believe play a role in mistaken-for-game hunting accidents: the availability heuristic, expectancy, confirmation bias, and optimism bias. We also present the assertion that experience may not safeguard a hunter, and may in fact do the opposite. Other contributing factors—buck fever, poor choice of clothing, and snap shooting—are discussed in relation to cognitive biases. However, there is currently a notable lack of research on the role of cognitive biases in hunting accidents per se. As a result, more work needs to be conducted to verify the conclusions of this white paper, for which a human factors approach must be taken

Adopt, adapt, and improve: Assessment of a new driver display in rail

This project evaluated the impact of a new enhanced information display intended as a cognitive aid on the operating performance of Locomotive Engineers (i.e. Train Drivers) within a large New Zealand freight rail network. The display previewed the upcoming route and presented information capable of optimising the performance of the locomotive. It did not exert any direct influence over the train and therefore did not take any decision-making capacity away from the driver. The addition of this technology represented a step-change for the organisation and a considerable investment for furthering safety and performance by improving the situation awareness of train drivers. Improving situation awareness is likely to lead to improved decision-making and hence performance and safety (Endsley, 1999) However, given the impact on ways of working for the train driver, and on the development of the organisation, acquiring insight into the cognitive, organisational and/or physical ergonomics impact of the technology was critical and attracted the need for a human factors assessment

Gemini/GMOS imaging of globular clusters in the Virgo galaxy NGC 4649 (M60)

We present Sloan g and i imaging from the Gemini Multi-object Spectrograph (GMOS) instrument on the Gemini North telescope for the globular cluster (GC) system around the Virgo galaxy NGC 4649 (M60). Our three pointings, taken in good seeing conditions, cover an area of about 90 square arcmin. We detect 2151 unresolved sources. Applying colour and magnitude selection criteria to this source list gives 995 candidate GCs. Our source list is greater than 90 per cent complete to a magnitude of i = 23.6, and has little contamination from background galaxies. We find fewer than half a dozen potential ultracompact dwarf galaxies around NGC 4649. Foreground extinction from the nearby spiral NGC 4647 is limited to be AV Hubble Space Telescope/WFPC2 imaging. As is commonly seen in other galaxies, the red GCs are concentrated towards the centre of the galaxy, having a steeper number density profile than the blue GC subpopulation. The varying ratio of red-to-blue GCs with radius can largely explain the overall GC system colour gradient. The underlying galaxy starlight has a similar density profile slope and colour to the red GCs. This suggests a direct connection between the galaxy field stars and the red GC subpopulation. We estimate a total GC population of 3700 ± 900, with the uncertainty dominated by the extrapolation to larger radii than observed. This total number corresponds to a specific frequency SN = 4.1 ± 1.0. Future work will present properties derived from GMOS spectra of the NGC 4649 GCs.Facultad de Ciencias Astronómicas y Geofísica

The globular cluster kinematics and galaxy dark matter content of NGC 4649 (M60)

From observations with the GMOS multislit spectrograph on the Gemini North telescope, we have obtained spectra for 39 globular cluster (GC) candidates in the Virgo giant elliptical galaxy NGC 4649 (M60), of which 38 are confirmed GCs. The clusters extend out to a radius of 260 arcsec (3.5 effective radii). We find no rotation of the GC system, with an upper limit of ν/σ < 0.6 at a confidence level of 95 per cent. The GC velocity dispersion is constant with radius, within the uncertainties. We fit isotropic models to the GC and stellar kinematics; these models yield an (M/L) V around 16 at 200 arcsec radius (16 kpc), an increase of a factor of 2 from the central M/L. We also use the mass profile as derived from X-rays to determine the orbital structure. Using axisymmetric orbit-based models and the X-ray mass profile, we find the orbital distribution is close to isotropic within 100 arcsec, and becomes tangentially biased beyond. Furthermore, when using the X-ray profile, we find a better fit to the kinematics compared to using a constant M/L model. Thus, both isotropic and axisymmetric orbit-based models give support for the presence of a dark matter halo in NGC 4649.Facultad de Ciencias Astronómicas y Geofísica

Gemini/GMOS spectra of globular clusters in the Virgo giant elliptical NGC 4649

NGC 4649 (M60) is one of a handful of giant Virgo ellipticals. We have obtained Gemini/GMOS (Gemini North Multi-Object Spectrograph) spectra for 38 globular clusters (GCs) associated with this galaxy. Applying the multi-index χ2 minimization technique of Proctor and Sansom with the single stellar population models of Thomas, Maraston and Korn, we derive ages, metallicities and α-element abundance ratios. We find several young (2-3 Gyr old) supersolar metallicity GCs, while the majority are old (>10 Gyr), spanning a range of metallicities from solar to [Z/H] = -2. At least two of these young GCs are at large projected radii of 17-20 kpc. The galaxy itself shows no obvious signs of a recent starburst, interaction or merger. A trend of decreasing α-element ratio with increasing metallicity is found.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Gemini/GMOS spectra of globular clusters in the Leo group elliptical NGC 3379

The Leo group elliptical NGC 3379 is one of the few normal elliptical galaxies close enough to make possible observations of resolved stellar populations, deep globular cluster (GC) photometry and high signal-to-noise ratio GC spectra. We have obtained Gemini/GMOS spectra for 22 GCs associated with NGC 3379. We derive ages, metallicities and α-element abundance ratios from simple stellar population models using the recent multi-index χ 2 minimization method of Proctor & Sansom. All of these GCs are found to be consistent with old ages, i.e. ≳10Gyr, with a wide range of metallicities. This is comparable to the ages and metallicities that Gregg et al. found a couple of years ago for resolved stellar populations in the outer regions of this elliptical. A trend of decreasing α-element abundance ratio with increasing metallicity is indicated. The projected velocity dispersion of the GC system is consistent with being constant with radius. Non-parametric, Isotropic models require a significant increase in the mass-to-light ratio at large radii. This result is in contrast to that of Romanowsky et al., who recently found a decrease in the velocity dispersion profile as determined from planetary nebulae (PN). Our constant dispersion requires a normal-sized dark halo, although without anisotropic models we cannot rigorously determine the dark halo mass. A two-sided χ 2 test over all radii gives a 2σ difference between the mass profile derived from our GCs compared to the PN-derived mass model of Romanowsky et al. However, if we restrict our analysis to radii beyond one effective radius and test if the GC velocity dispersion is consistently higher, we determine a > 3σ difference between the mass models, and hence we favour the conclusion that NGC 3379 does indeed have dark matter at large radii in its halo.Facultad de Ciencias Astronómicas y Geofísica