Seeing College Students as Adults: Learner-Centered Strategies for Information Literacy Instruction

Information literacy instruction is a responsibility of many academic librarians and much has been written about approaches to this endeavor. This article explores ways in which pedagogy from the field of adult education can inform information literacy instruction in higher education. A review of the literature on adult learning is followed by suggested ways that academic librarians can incorporate these learning strategies into their instruction. A case description examines how librarians at one institution have addressed adult learning styles and classroom realities by using surveys for instructional pre-assessment. While further research is needed to assess the impact of these techniques, this article suggests that academic librarians can provide effective information literacy instruction and promote lifelong learning by treating students as adult learners

Supernovae Rates: A Cosmic History

We discuss the cosmic history of supernovae on the basis of various assumptions and recent data on the star formation history. We show that supernova rates as a function of redshift can be used to place significant constraints on progenitor models, on the star formation history, and on the importance of dust obscuration. We demonstrate that it is unlikely that the current observational indications for the existence of a cosmological constant are merely an artifact of the dominance of different progenitor classes at different redshift intervals.Comment: Accepted for publication in The Astrophysical Journa

A Novel Approach to Recreational Reading: Creating a Virtual Collection on a Shoestring

Reading for recreation has been tied to academic achievement and lifelong learning, but not all academic libraries have the capacity to offer a separate recreational reading collection for their users. A low/no-cost option is to create a virtual recreational reading collection that allows patrons to browse for print titles by genre or book cover, much as they would in a bookstore or physical collection. The authors recently implemented this solution at their institution by dynamically compiling records of existing titles belonging to genres that are often of interest to recreational readers. This article addresses the justification for investing staff time in promoting recreational reading, discusses the technology employed to create and maintain a virtual collection, and shares the impacts of this effort on circulation

The evolution of the AGN content in groups up to z~1

Determining the AGN content in structures of different mass/velocity dispersion and comparing them to higher mass/lower redshift analogs is important to understand how the AGN formation process is related to environmental properties. We use our well-tested cluster finding algorithm to identify structures in the GOODS North and South fields, exploiting the available spectroscopic redshifts and accurate photometric redshifts. We identify 9 structures in GOODS-south (presented in a previous paper) and 8 new structures in GOODS-north. We only consider structures where at least 2/3 of the members brighter than M_R=-20 have a spectroscopic redshift. For those group members that coincide with X-ray sources in the 4 and 2 Msec Chandra source catalogs respectively, we determine if the X-ray emission originates from AGN activity or it is related to the galaxies' star-formation activity. We find that the fraction of AGN with Log L_H > 42 erg/s in galaxies with M_R < -20 is on average 6.3+-1.3%, much higher than in lower redshift groups of similar mass and more than double the fraction found in massive clusters at a similarly high redshift. We then explore the spatial distribution of AGN in the structures and find that they preferentially populate the outer regions. The colors of AGN host galaxies in structures tend to be confined to the green valley, thus avoiding the blue cloud and, partially, also the red-sequence, contrary to what happens in the field. We finally compare our results to the predictions of two sets of semi analytic models to investigate the evolution of AGN and evaluate potential triggering and fueling mechanisms. The outcome of this comparison attests the importance of galaxy encounters, not necessarily leading to mergers, as an efficient AGN triggering mechanism. (abridged)Comment: 11 pages, 8 figures, Accepted accepted for publication in A&

Adaptive Optics Discovery of Supernova 2004ip in the Nuclear Regions of the Luminous Infrared Galaxy IRAS 18293-3413

We report a supernova discovery in Ks-band images from the NAOS CONICA adaptive optics (AO) system on the ESO Very Large Telescope (VLT). The images were obtained as part of a near-infrared search for highly-obscured supernovae in the nuclear regions of luminous and ultraluminous infrared galaxies. SN 2004ip is located within a circumnuclear starburst at 1.4 arcsec (or 500 pc) projected distance from the K-band nucleus of the luminous infrared galaxy IRAS 18293-3413. The supernova luminosity and light curve are consistent with a core-collapse event suffering from a host galaxy extinction of up to about 40 magnitudes in V-band which is as expected for a circumnuclear starburst environment. This is the first supernova to be discovered making use of AO correction and demonstrates the potential of the current 8-meter class telescopes equipped with AO in discovering supernovae from the innermost nuclear regions of luminous and ultraluminous infrared galaxies.Comment: 4 pages, 3 figures, ApJ Letters (accepted

The North Dakota Beef Industry Survey: Implications for Extension

A portion of the North Dakota Beef Industry Survey was developed to determine how educational programs can evolve to meet future needs of North Dakota beef producers. Of the 2,500 surveys mailed out to beef producers, 527 responses were completed and returned. Results highlight the level of education of North Dakota beef producers, anticipated use of technology in the next 1 to 5 years, educational meeting attendance, and preferred methods of receiving educational programming. Future programming efforts should be developed and delivered using a multi-faceted approach to ensure acceptance and utilization by producers with varying degrees of technology reliance

Kadanoff-Baym approach to time-dependent quantum transport in AC and DC fields

We have developed a method based on the embedded Kadanoff-Baym equations to study the time evolution of open and inhomogeneous systems. The equation of motion for the Green's function on the Keldysh contour is solved using different conserving many-body approximations for the self-energy. Our formulation incorporates basic conservation laws, such as particle conservation, and includes both initial correlations and initial embedding effects, without restrictions on the time-dependence of the external driving field. We present results for the time-dependent density, current and dipole moment for a correlated tight binding chain connected to one-dimensional non-interacting leads exposed to DC and AC biases of various forms. We find that the self-consistent 2B and GW approximations are in extremely good agreement with each other at all times, for the long-range interactions that we consider. In the DC case we show that the oscillations in the transients can be understood from interchain and lead-chain transitions in the system and find that the dominant frequency corresponds to the HOMO-LUMO transition of the central wire. For AC biases with odd inversion symmetry odd harmonics to high harmonic order in the driving frequency are observed in the dipole moment, whereas for asymmetric applied bias also even harmonics have considerable intensity. In both cases we find that the HOMO-LUMO transition strongly mixes with the harmonics leading to harmonic peaks with enhanced intensity at the HOMO-LUMO transition energy.Comment: 16 pages, 9 figures. Submitted at "Progress in Nonequilibrium Green's Functions IV" conferenc

Finite elements and the discrete variable representation in nonequilibrium Green's function calculations. Atomic and molecular models

In this contribution, we discuss the finite-element discrete variable representation (FE-DVR) of the nonequilibrium Green's function and its implications on the description of strongly inhomogeneous quantum systems. In detail, we show that the complementary features of FEs and the DVR allows for a notably more efficient solution of the two-time Schwinger/Keldysh/Kadanoff-Baym equations compared to a general basis approach. Particularly, the use of the FE-DVR leads to an essential speedup in computing the self-energies. As atomic and molecular examples we consider the He atom and the linear version of H$_3^+$ in one spatial dimension. For these closed-shell models we, in Hartree-Fock and second Born approximation, compute the ground-state properties and compare with the exact findings obtained from the solution of the few-particle time-dependent Schr\"odinger equation.Comment: 12 pages, 3 figures, submitted as proceedings of conference "PNGF IV

High Redshift Supernova Rates

We use a sample of 42 supernovae detected with the Advanced Camera for Surveys on-board the Hubble Space Telescope as part of the Great Observatories Origins Deep Survey to measure the rate of core collapse supernovae to z~0.7 and type Ia supernovae to z~1.6. This significantly increases the redshift range where supernova rates have been estimated from observations. The rate of core collapse supernovae can be used as an independent probe of the cosmic star formation rate. Based on the observations of 17 core collapse supernovae, we measure an increase in the core collapse supernova rate by a factor of 1.6 in the range 0.3<z<0.7, and an overall increase by a factor of 7 to z~0.7 in comparison to the local core collapse supernova rate. The increase in the rate in this redshift range in consistent with recent measurements of the star formation rate derived from UV-luminosity densities and IR datasets. Based on 25 type Ia supernovae, we find a SN Ia rate that is a factor 3-5 higher at z~1 compared to earlier estimates at lower redshifts (z<0.5), implying that the type Ia supernova rate traces a higher star formation rate at redshifts z>1 compared to low redshift. At higher redshift (z>1), we find a suggested decrease in the type Ia rate with redshift. This evolution of the Ia rate with redshift is consistent with a type Ia progenitor model where there is a substantial delay between the formation of the progenitor star and the explosion of the supernova. Assuming that the type Ia progenitor stars have initial main sequence masses 3-8 M_Sun, we find that 5-7% of the available progenitors explode as type Ia supernovae.Comment: 16 pages, 3 figures, accepted for publication in the Astrophysical Journa

Near-IR Search for Lensed Supernovae Behind Galaxy Clusters - II. First Detection and Future Prospects

Powerful gravitational telescopes in the form of massive galaxy clusters can be used to enhance the light collecting power over a limited field of view by about an order of magnitude in flux. This effect is exploited here to increase the depth of a survey for lensed supernovae at near-IR wavelengths. A pilot SN search program conducted with the ISAAC camera at VLT is presented. Lensed galaxies behind the massive clusters A1689, A1835 and AC114 were observed for a total of 20 hours split into 2, 3 and 4 epochs respectively, separated by approximately one month to a limiting magnitude J<24 (Vega). Image subtractions including another 20 hours worth of archival ISAAC/VLT data were used to search for transients with lightcurve properties consistent with redshifted supernovae, both in the new and reference data. The feasibility of finding lensed supernovae in our survey was investigated using synthetic lightcurves of supernovae and several models of the volumetric Type Ia and core-collapse supernova rates as a function of redshift. We also estimate the number of supernova discoveries expected from the inferred star formation rate in the observed galaxies. The methods consistently predict a Poisson mean value for the expected number of SNe in the survey between N_SN=0.8 and 1.6 for all supernova types, evenly distributed between core collapse and Type Ia SN. One transient object was found behind A1689, 0.5" from a galaxy with photometric redshift z_gal=0.6 +- 0.15. The lightcurve and colors of the transient are consistent with being a reddened Type IIP SN at z_SN=0.59. The lensing model predicts 1.4 magnitudes of magnification at the location of the transient, without which this object would not have been detected in the near-IR ground based search described in this paper (unlensed magnitude J~25). (abridged)Comment: Accepted by AA, matches journal versio