A preliminary study of head-up display assessment techniques. 2: HUD symbology and panel information search time

Twelve commercial pilots were shown 50 high-fidelity slides of a standard aircraft instrument panel with the airspeed, altitude, ADI, VSI, and RMI needles in various realistic orientations. Fifty slides showing an integrated head-up display (HUD) symbology containing an equivalent number of flight parameters as above (with flight path replacing VSI) were also shown. Each subject was told what flight parameter to search for just before each slide was exposed and was given as long as needed (12 sec maximum) to respond by verbalizing the parameter's displayed value. The results for the 100-percent correct data indicated that: there was no significant difference in mean reaction time (averaged across all five flight parameters) between the instrument panel and HUD slides; and a statistically significant difference in mean reaction time was found in responding to different flight parameters

Testing the Modern Merger Hypothesis via the Assembly of Massive Blue Elliptical Galaxies in the Local Universe

The modern merger hypothesis offers a method of forming a new elliptical galaxy through merging two equal-mass, gas-rich disk galaxies fuelling a nuclear starburst followed by efficient quenching and dynamical stabilization. A key prediction of this scenario is a central concentration of young stars during the brief phase of morphological transformation from highly-disturbed remnant to new elliptical galaxy. To test this aspect of the merger hypothesis, we use integral field spectroscopy to track the stellar Balmer absorption and 4000\AA\ break strength indices as a function of galactic radius for 12 massive (${\rm M_{*}}\ge10^{10}{\rm M_{\odot}}$), nearby (${\rm z}\le0.03$), visually-selected plausible new ellipticals with blue-cloud optical colours and varying degrees of morphological peculiarities. We find that these index values and their radial dependence correlate with specific morphological features such that the most disturbed galaxies have the smallest 4000\AA\ break strengths and the largest Balmer absorption values. Overall, two-thirds of our sample are inconsistent with the predictions of the modern merger hypothesis. Of these eight, half exhibit signatures consistent with recent minor merger interactions. The other half have star formation histories similar to local, quiescent early-type galaxies. Of the remaining four galaxies, three have the strong morphological disturbances and star-forming optical colours consistent with being remnants of recent, gas-rich major mergers, but exhibit a weak, central burst consistent with forming $\sim5\%$ of their stars. The final galaxy possesses spectroscopic signatures of a strong, centrally-concentrated starburst and quiescent core optical colours indicative of recent quenching (i.e., a post-starburst signature) as prescribed by the modern merger hypothesis.Comment: 25 pages, 37 figures, accepted to MNRA

The Different Environmental Dependencies of Star-formation for Giant and Dwarf Galaxies

We examine the origins of the bimodality observed in the global properties of galaxies around a stellar mass of 3x10^10 M_sun by comparing the environmental dependencies of star-formation for the giant and dwarf galaxy populations. The Sloan Digital Sky Survey DR4 spectroscopic dataset is used to produce a sample of galaxies in the vicinity of the supercluster centered on the cluster A2199 at z=0.03 that is ~90% complete to a magnitude limit of M*+3.3. From these we measure global trends with environment for both giant (M_r<-20 mag) and dwarf (-19<M_r<-17.8 mag) subsamples using the luminosity-weighted mean stellar age and H_alpha emission as independent measures of star-formation history. The fraction of giant galaxies classed as old (t>7 Gyr) or passive (EW[H_alpha]<4 A) falls gradually from ~80% in the cluster cores to ~40% in field regions beyond 3-4 R_virial, as found in previous studies. In contrast, we find that the dwarf galaxy population shows a sharp transition at ~1 R_virial, from being predominantly old/passive within the cluster, to outside where virtually all galaxies are forming stars and old/passive galaxies are only found as satellites to more massive galaxies. These results imply fundamental differences in the evolution of giant and dwarf galaxies: whereas the star-formation histories of giant galaxies are determined primarily by their merger history, star-formation in dwarf galaxies is much more resilient to the effects of major mergers. Instead dwarf galaxies become passive only once they become satellites within a more massive halo, by losing their halo gas reservoir to the host halo, or through other environment-related processes such as galaxy harassment and/or ram-pressure stripping.Comment: 4 pages, 4 figures, accepted for publication in ApJ

Cosmic dance in the Shapley Concentration Core - I. A study of the radio emission of the BCGs and tailed radio galaxies

The Shapley Concentration ($z\approx0.048$) covers several degrees in the Southern Hemisphere, and includes galaxy clusters in advanced evolutionary stage, groups of clusters in the early stages of merger, fairly massive clusters with ongoing accretion activity, and smaller groups located in filaments in the regions between the main clusters. With the goal to investigate the role of cluster mergers and accretion on the radio galaxy population, we performed a multi-wavelength study of the BCGs and of the galaxies showing extended radio emission in the cluster complexes of Abell 3528 and Abell 3558. Our study is based on a sample of 12 galaxies. We observed the clusters with the GMRT at 235, 325 and 610 MHz, and with the VLA at 8.46 GHz. We complemented our study with the TGSS at 150 MHz, the SUMSS at 843 MHz and ATCA at 1380, 1400, 2380, and 4790 MHz data. Optical imaging with ESO-VST and mid-IR coverage with WISE are also available for the host galaxies. We found deep differences in the properties of the radio emission of the BCGs in the two cluster complexes. The BCGs in the A3528 complex and in A3556, which are relaxed cool-core objects, are powerful active radio galaxies. They also present hints of restarted activity. On the contrary, the BCGs in A3558 and A3562, which are well known merging systems, are very faint, or quiet, in the radio band. The optical and IR properties of the galaxies are fairly similar in the two complexes, showing all passive red galaxies. Our study shows remarkable differences in the radio properties of the BGCs, which we relate to the different dynamical state of the host cluster. On the contrary, the lack of changes between such different environments in the optical band suggests that the dynamical state of galaxy clusters does not affect the optical counterparts of the radio galaxies, at least over the life-time of the radio emission.Comment: 24 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

Seismic response of L’Aquila (Central Appennines, Italy) from 2D numerical simulation

Experimental and modeling approaches fulfill complementary needs in the assessment of the seismic soil response. Here we present some results from 2D simulation performed for the L’Aquila basin (Central Appennines, Italy). The city of L’Aquila on April 6th, 2009 at 01:32 UTC was struck by a magnitude Mw=6.3 earthquake localized about 2 kilometers west of the city centre at hypocentral depth 9 km. The city of L’Aquila suffered wide spread destructive damage in its historical centre where housing is mainly 2 to 3 storey medieval masonry. Several reinforced concrete buildings built in the late 70s collapsed in the south-west section of the city and also monumental, historical churches were severely damaged. Because of its location, the ground motion recorded in the city is strongly influenced by the source rupture mechanism, nonetheless, local amplification are expected to have influenced the ground shacking. L’Aquila is indeed built over a Quaternary terraced alluvial-lacustrine basin with a rather complex lithology as well as surface topography. The 2D seismic modeling of L’Aquila terrace was already performed by several authors along transversally oriented (NE-SW) geological sections. In this study we present some new results obtained by the use of longitudinal cross sections (NW-SE) in order to better understand the role of lateral geological heterogeneities as derived by recent geological and geophysical data. The simulations have been performed using the impedance-operator-based numerical code. The models of L’Aquila terrace are based on geological and geophysical investigations performed in the framework of the micro-zoning activities of the city following the disastrous April 6th 2009 Mw=6.3 earthquake and in subsequent studies. The depth to the bedrock of the basin is constrained by gravimetric and deep borehole data with an estimated maximum depth of about 300 m. The basin is filled by silt and silty-clay of lacustrine origin topped by a breccia layer (BrA) of gravitational-fluvial origin. BrA does not extend continuously over the terrace and in particular in the southern area of the city it is locally replaced by silt and silty-clay of lacustrine origin with lens of BrA and gravel with silt. Locally, on the top of the terrace lens of less competent red silt were found by the recent deep borehole surveys performed in the micro-zoning activities. We have further constrained our 2D models using the resonance frequencies from noise and earthquake spectral ratios for selected sites. The wave velocities have been inferred by MASW and cross-hole analyses. We have compared the spectral ratios obtained from SH, P-SV and Rayleigh incident waves field in the range 0 -90 to the observed spectral ratios computed using the earthquake aftershocks recorded by the micro-zoning portable network. The modeling results are able to match the resonance frequency obtained by seismological data and to verify the role of the reversal in the velocity-depth profile and the lateral continuity of the top fast layer (BrA)

Auto-calibration of ultrasonic lubricant-film thickness measurements

The measurement of oil film thickness in a lubricated component is essential information for performance monitoring and design. It is well established that such measurements can be made ultrasonically if the lubricant film is modelled as a collection of small springs. The ultrasonic method requires that component faces are separated and a reference reflection recorded in order to obtain a reflection coefficient value from which film thickness is calculated. The novel and practically useful approach put forward in this paper and validated experimentally allows reflection coefficient measurement without the requirement for a reference. This involves simultaneously measuring the amplitude and phase of an ultrasonic pulse reflected from a layer. Provided that the acoustic properties of the substrate are known, the theoretical relationship between the two can be fitted to the data in order to yield reflection coefficient amplitude and phase for an infinitely thick layer. This is equivalent to measuring a reference signal directly, but importantly does not require the materials to be separated. The further valuable aspect of this approach, which is demonstrated experimentally, is its ability to be used as a self-calibrating routine, inherently compensating for temperature effects. This is due to the relationship between the amplitude and phase being unaffected by changes in temperature which cause unwanted changes to the incident pulse. Finally, error analysis is performed showing how the accuracy of the results can be optimized. A finding of particular significance is the strong dependence of the accuracy of the technique on the amplitude of reflection coefficient input data used. This places some limitations on the applicability of the technique. © 2008 IOP Publishing Ltd

Seismic response and wavefield characterization using a very dense 2D seismic array on an active landslide (Cavola, Italy)

A dense 2D array (95 broad-band stations) was installed in a grid-like configuration over a 130x56 m area on the active landslide of Cavola in northern Apennines. Outcropping rocks consist of Monte Piano (fractured flysch and clayey melanges) and Ranzano (muddy and sandstone turbidite) formations of Eocene-Oligocene age. These units are covered by a 4-km long landslide with maximum thickness more than 60 m. In historical times there are three instances of activity triggered by meteorological events, in 1938, 1940, and 1960. The latter event was the most damaging, involving an area of 1.3 km2 and partial destruction of the Cavola village. Recent SAR interferometric analyses coupled to inclinometer data for the supposedly dormant period 1995-2001 show movements between 10-15 mm/yr affecting mainly areas close to the landslide side-scarps and to a new industrial district with active sliding surface at a depth of 10-15 m. The landslide structure beneath the array was reconstructed by means of active and passive seismic surveys, in-situ velocity measurements and geoelectrical tomography obtaining clay thickness ranging from 0 to 45 m and with average shear-velocity of 350 m/s. The inferred model is used for numerical 2D simulation of earthquake ground motion for different incidence angle and type of waves. The data from 11 of more than 100 local earthquakes recorded at the array have been used for the comparison with model results. The long data records (3 months of continuous recording) allow investigation of properties of ambient noise in terms of temporal stability and wavefield composition. We find that local industrial sources affect the H/V spectral ratios and their interpretation in terms of resonant frequencies. Analysis of noise polarization is also performed, revealing different patterns depending on the nature of the noise source

Identification of Problems in Campus Recreation Programs in North America

In campus recreation programs, major problem areas within (a) technology, (b) personnel, and (c) perception and value were identified. The subjects were campus recreation directors throughout North America. The surveyed directors expressed the extent to which they agreed or disagreed with literaturebased, potential problem areas within campus recreation programs. Areas primarily agreed upon as being major problem areas within campus recreation were: the availability of quality officials (61 %), perception of program by institution (49%), and value of program as perceived by higher administration (47%). Generally, in order to improve programs, directors should place an emphasis on attaining and training quality officials and implement a public relations campaign that positively portrays their program

A Survey of Campus Recreation Directors at NIRSA Institutions: Activities Emphasized, Student Participation Patterns, Trends and Future Offerings Contemplated

A survey, using an instrument constructed expressly for this investigation, was conducted of directors of campus recreation at all 682 NIRSA colleges and universities in the United States and Canada to determine the current status of (a) the degree of emphasis institutions currently place on nine categories of sports and recreational activities, (b) the percentage of students, undergraduate and graduate, actually participating in each of these nine categories of activities, (c) future recreational activities and programs, not currently offered to students, but being considered for inclusion within the next 12 months, and (d) future trends in terms of problems (challenges and opportunities) facing college campus recreation departments. Two hundred and sixty-nine schools returned usable surveys for a 39% rate of return. This investigation provides a snapshot of specific current practices and programming offerings of campus Recreation Directors, as well as their opinions in terms of future programming plans and anticipated trends affecting their campus recreation departments. The data were analyzed in light of the locations of the responding institutions within the six regions of NIRSA, the size of the institutions and whether the schools were classified as public or private. The nine categories of recreational activities included: (a) intramurals, (b) club sports, (c) open recreation, (d) outdoor recreation, (e) group exercise/aerobics, (f) aquatics, (g) instructional programming, (h) special events, and (i) youth and family activities