3,001 research outputs found

    Landslides in sensitive soils, Tauranga, New Zealand.

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    In the Tauranga region sensitive soil failures commonly occur after heavy rainfall events, causing considerable infrastructure damage. Several notable landslides include a large failure at Bramley Drive, Omokoroa in 1979, the Ruahihi Canal collapse in 1981, and numerous landslides in May 2005; recently the Bramley Drive scarp was reactivated in 2011. These failures are associated with materials loosely classified as the Pahoia Tephras - a mixture of rhyolitic pyroclastic deposits of approximately 1 Ma. The common link with extreme rainfall events suggests a pore water pressure control on the initiation of these failures. Recent research on the structure of the soils shows a dominance of halloysite clay minerals packed loosely in arrangements with high porosity (51 – 77 %), but with almost entirely micropores. This leads us to conclude that the permeability is very low, and the materials remain continuously wet. The formation of halloysite is encouraged by a wet environment with no episodes of drying, supporting this assumption. A high-resolution CPT trace at Bramley Drive indicates induced pore water pressures rising steadily to a peak at approximately 25 m depth; this depth coincides with the base of the landslide scarp. We infer that elevated pore water pressures develop within this single, thick aquifer, triggering failure through reduced effective stresses. The inactive halloysite clay mineral results in low plasticity indices (13 – 44 %) and hence high liquidity indices (1.2 – 2.4) due to the saturated pore space; remoulding following failure is sudden and dramatic and results in large debris runout distances

    Substructure in clusters containing wide-angle tailed radio galaxies. I. New redshifts

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    We present new redshifts and positions for 635 galaxies in nine rich clusters containing Wide-Angle Tailed (WAT) radio galaxies. Combined with existing data, we now have a sample of 18 WAT-containing clusters with more than 10 redshifts. This sample contains a substantial portion of the WAT clusters in the VLA 20 cm survey of Abell clusters, including 75% of WAT clusters in the complete survey (z0.09. It is a representative sample which should not contain biases other than selection by radio morphology. We graphically present the new data using histograms and sky maps. A semi-automated procedure is used to search for emission lines in the spectra in order to add and verify galaxy redshifts. We find that the average apparent fraction of emission line galaxies is about 9% in both the clusters and the field. We investigate the magnitude completeness of our redshift surveys with CCD data for a test case, Abell 690. This case indicates that our galaxy target lists are deeper than the detection limit of a typical MX exposure, and they are 82% complete down to R=19.0. The importance of the uniformity of the placement of fibers on targets is posited, and we evaluate this in our datasets. We find some cases of non-uniformities which may influence dynamical analyses. A second paper will use this database to look for correlations between the WAT radio morphology and the cluster's dynamical state.Comment: 15 pages, 5 figures, 7 tables. To appear in the Astronomical Journa

    PANEL: Are Students Our Customers? Perils and Pitfalls of Students as Customers

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    Customer service has been a part of marketing for years. A common definition is: “Customer service is the act of taking care of the customer\u27s needs by providing and delivering professional, helpful, high quality service and assistance before, during, and after the customer\u27s requirements are met.” This approach has been main streamed in higher education by Neal Raisman in his four books on the subject. This panel will present and discuss the perils and pitfalls of this approach in higher education along with a summary of an informal survey of marketing Professors

    PANEL: Changing Expectations from Department Chairs in the Dynamic Environment of Higher Education

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    The dynamic environment of higher education defines and redefines roles of faculty and administrators. Department chairs have a unique position in colleges as they are part of the faculty as well as administrators. Expectations from department chairs include a long list of activities. They have to deal with a variety of tenured and tenure track faculty at different levels, such as instructors, senior instructors, assistant, associate, full professors, and per-course faculty (adjuncts). Students are another group for them to manage, including undergraduate, graduate students with different concentrations, majors and minors as well as transfer, study-away, study abroad students besides graduate assistants, work-study, and regular student workers. They also must interact with the staff in their department along with other departments or units in their college and other units of their universities. Most importantly, they have to get along and work with other administrators. What’s counted so far involve direct and indirect internal stakeholders. There are also external stakeholders that consist of corporate executives, small business owners and advisory boards that have numerous roles from internships, student placement opportunities, fundraising engagements, guest speaking, client projects, etc. While department chairs need to take all internal and external stakeholders into consideration, they have to perform many departmental activities from curriculum and program development and review, class scheduling, faculty, staff, student evaluations, to recruitment, enrollment and retention management, budgeting and control. Furthermore, they are expected to stay transparent, diverse, collegial, and productive while managing these complex relationships for hitting multiple moving targets in a very dynamic environment. To further complicate the situation faced by chairs, many are finding that their paperwork and administrative responsibilities have proliferated. Indeed, while attempting to navigate the increasingly complex and multi-faceted environment discussed above, many chairs are faced with increasing paperwork and administrative responsibilities that can easily consume 20-30+ hours a week. In conclusion, this panel will discuss best practices of becoming a department chair and sustaining that role over number of years successfully. Specifically, it will help benchmark best practices for department chairs in implementing their visionary leadership for data driven decision making without losing sight of human touch

    The Santa Fe Light Cone Simulation Project: I. Confusion and the WHIM in Upcoming Sunyaev-Zel'dovich Effect Surveys

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    We present the first results from a new generation of simulated large sky coverage (~100 square degrees) Sunyaev-Zeldovich effect (SZE) cluster surveys using the cosmological adaptive mesh refinement N-body/hydro code Enzo. We have simulated a very large (512^3h^{-3}Mpc^3) volume with unprecedented dynamic range. We have generated simulated light cones to match the resolution and sensitivity of current and future SZE instruments. Unlike many previous studies of this type, our simulation includes unbound gas, where an appreciable fraction of the baryons in the universe reside. We have found that cluster line-of-sight overlap may be a significant issue in upcoming single-dish SZE surveys. Smaller beam surveys (~1 arcmin) have more than one massive cluster within a beam diameter 5-10% of the time, and a larger beam experiment like Planck has multiple clusters per beam 60% of the time. We explore the contribution of unresolved halos and unbound gas to the SZE signature at the maximum decrement. We find that there is a contribution from gas outside clusters of ~16% per object on average for upcoming surveys. This adds both bias and scatter to the deduced value of the integrated SZE, adding difficulty in accurately calibrating a cluster Y-M relationship. Finally, we find that in images where objects with M > 5x10^{13} M_{\odot} have had their SZE signatures removed, roughly a third of the total SZE flux still remains. This gas exists at least partially in the Warm Hot Intergalactic Medium (WHIM), and will possibly be detectable with the upcoming generation of SZE surveys.Comment: 14 pages, 13 figures, version accepted to ApJ. Major revisions mad

    A catalog of Nearby Poor Clusters of Galaxies

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    A catalog of 732 optically selected, nearby poor clusters of galaxies covering the entire sky north of −3∘\rm -3^{\circ} declination is presented. The poor clusters, called WBL clusters, were identified as concentrations of 3 or more galaxies with photographic magnitudes brighter than 15.7, possessing a galaxy surface overdensity of 104/310^{4/3}. These criteria are consistent with those used in the identification of the original Yerkes poor clusters, and this new catalog substantially increases the sample size of such objects. These poor clusters cover the entire range of galaxy associations up to and including Abell clusters, systematically including poor and rich galaxy systems spanning over three orders of magnitude in the cluster mass function. As a result, this new catalog contains a greater diversity of richness and structures than other group catalogs, such as the Hickson or Yerkes catalogs. The information on individual galaxies includes redshifts and cross-references to other galaxy catalogs. The entries for the clusters include redshift (where available) and cross-references to other group and cluster catalogs.Comment: 27 pages, 7 figures, + one 20-page landscape table, accepted for publication in A
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