The DISCOVER Model: A Prescriptive Method for Instructional Tool Selection and Use in Seeking to Boost Instructor Immediacy and Social Presence in Online Courses

Higher education faculty who teach online can face numerous challenges in providing optimal experiences for their students. Besides their potentially limited instructional design expertise and understanding of how to optimize technology to support learning, faculty may have difficulties in finding ways to make themselves be perceived as real people who are approachable, caring, and likeable due to online nature of the learning context. As a preliminary means to address these issues, the current study focused on the development of the DISCOVER Model, which was designed to provide higher education faculty with a framework to develop actionable plans in the creation of audio and video media assets while focusing on best practices to boost student perceptions of instructor immediacy and instructor social presence. This model, developed as an enhancement to the ADDIE model of instructional design, provides a sequence of eight steps across design and development, and implementation and evaluation phases, that guide instructors through making informed choices in creating media assets and revising them. This mixed-method study took place at a university in the Appalachian region of the United States and focused on two undergraduate courses and two graduate courses taught by three instructors. The instructors used The DISCOVER Model to create media assets for their courses and 136 students opted into completing an online survey about their experiences that sought to measure their perceptions of instructor immediacy and social presence. Instructors participated in regular meetings and a summative interview with the researcher and six students were interviewed. Instructors were also assigned model adherence scores by the researcher based on how closely they were perceived to follow the model in creating their media assets. The results indicated that instructors who showed high model adherence had students who indicated moderately high perceptions of instructor social presence and immediacy. Further, graduate students indicated higher perceptions of social presence perceptions than undergraduate students. Findings and implications were discussed

Theory of the propagation of coupled waves in arbitrarily-inhomogeneous stratified media

We generalize the invariant imbedding theory of the wave propagation and derive new invariant imbedding equations for the propagation of arbitrary number of coupled waves of any kind in arbitrarily-inhomogeneous stratified media, where the wave equations are effectively one-dimensional. By doing this, we transform the original boundary value problem of coupled second-order differential equations to an initial value problem of coupled first-order differential equations, which makes the numerical solution of the coupled wave equations much easier. Using the invariant imbedding equations, we are able to calculate the matrix reflection and transmission coefficients and the wave amplitudes inside the inhomogeneous media exactly and efficiently. We establish the validity and the usefulness of our results by applying them to the propagation of circularly-polarized electromagnetic waves in one-dimensional photonic crystals made of isotropic chiral media. We find that there are three kinds of bandgaps in these structures and clarify the nature of these bandgaps by exact calculations.Comment: 7 pages, 1 figure, to appear in Europhys. Let

Results of a Second Year of Therapy with the 12-Month Histrelin Implant for the Treatment of Central Precocious Puberty

Background. Gonadotropin releasing hormone analogs (GnRHas) are standard of care for central precocious puberty (CPP). The histrelin subcutaneous implant is safe and effective in the treatment of CPP for one year. Objective. The study evaluates a second year of therapy in children with CPP who received a new implant after one year of treatment. Methods. A prospective one-year study following an initial 12-month treatment period was conducted. Results. Thirty-one patients (29 girls) aged 7.7 ± 1.5 years received a second implant. Eighteen were naïve to GnRHa therapy at first implantation. Peak LH declined from 0.92 ± 0.58 mIU/mL at 12 months to 0.51 ± 0.33 mIU/mL at 24 months (P < .0001) in naïve subjects, and from 0.74 ± 0.50 mIU/mL at 12 months to 0.45 ± 0.35 mIU/mL at 24 months (P = .0081) in previously treated subjects. Predicted adult height increased by 5.1 cm at 24 months (P = .0001). Minor implant site reactions occurred in 61%, while minor difficulties with explantation occurred in 32.2% of subjects. Conclusion. The histrelin implant demonstrates profound hypothalamic-pituitary-gonadal axis suppression when a new implant is placed for a second year of treatment. Prospective follow-up of this therapeutic modality for the treatment of CPP is needed

500 Days of SN 2013dy: spectra and photometry from the ultraviolet to the infrared

SN 2013dy is a Type Ia supernova for which we have compiled an extraordinary dataset spanning from 0.1 to ~ 500 days after explosion. We present 10 epochs of ultraviolet (UV) through near-infrared (NIR) spectra with HST/STIS, 47 epochs of optical spectra (15 of them having high resolution), and more than 500 photometric observations in the BVrRiIZYJH bands. SN 2013dy has a broad and slowly declining light curve (delta m(B) = 0.92 mag), shallow Si II 6355 absorption, and a low velocity gradient. We detect strong C II in our earliest spectra, probing unburned progenitor material in the outermost layers of the SN ejecta, but this feature fades within a few days. The UV continuum of SN 2013dy, which is strongly affected by the metal abundance of the progenitor star, suggests that SN 2013dy had a relatively high-metallicity progenitor. Examining one of the largest single set of high-resolution spectra for a SN Ia, we find no evidence of variable absorption from circumstellar material. Combining our UV spectra, NIR photometry, and high-cadence optical photometry, we construct a bolometric light curve, showing that SN 2013dy had a maximum luminosity of 10.0^{+4.8}_{-3.8} * 10^{42} erg/s. We compare the synthetic light curves and spectra of several models to SN 2013dy, finding that SN 2013dy is in good agreement with a solar-metallicity W7 model.Comment: 22 pages, 18 figures, replaced with version accecpted for publication in MNRA

Iterative graph cuts for image segmentation with a nonlinear statistical shape prior

Shape-based regularization has proven to be a useful method for delineating objects within noisy images where one has prior knowledge of the shape of the targeted object. When a collection of possible shapes is available, the specification of a shape prior using kernel density estimation is a natural technique. Unfortunately, energy functionals arising from kernel density estimation are of a form that makes them impossible to directly minimize using efficient optimization algorithms such as graph cuts. Our main contribution is to show how one may recast the energy functional into a form that is minimizable iteratively and efficiently using graph cuts.Comment: Revision submitted to JMIV (02/24/13

Correlation Effects in Nuclear Transparency

The Glauber approximation is used to calculate the contribution of nucleon correlations in high-energy $A(e,e'N)$ reactions. When the excitation energy of the residual nucleus is small, the increase of the nuclear transparency due to correlations between the struck nucleon and the other nucleons is mostly compensated by a decrease of the transparency due to the correlations between non detected nucleons. We derive Glauber model predictions for nuclear transparency for the differential cross section when nuclear shell level excitations are measured. The role of correlations in color transparency is briefly discussed.Comment: 24 pages revtex, 4 uuencoded PostScript Figures as separate fil

Extensive Spectroscopy and Photometry of the Type IIP Supernova 2013ej

We present extensive optical ($UBVRI$, $g'r'i'z'$, and open CCD) and near-infrared ($ZYJH$) photometry for the very nearby Type IIP SN ~2013ej extending from +1 to +461 days after shock breakout, estimated to be MJD $56496.9\pm0.3$. Substantial time series ultraviolet and optical spectroscopy obtained from +8 to +135 days are also presented. Considering well-observed SNe IIP from the literature, we derive $UBVRIJHK$ bolometric calibrations from $UBVRI$ and unfiltered measurements that potentially reach 2\% precision with a $B-V$ color-dependent correction. We observe moderately strong Si II $\lambda6355$ as early as +8 days. The photospheric velocity ($v_{\rm ph}$) is determined by modeling the spectra in the vicinity of Fe II $\lambda5169$ whenever observed, and interpolating at photometric epochs based on a semianalytic method. This gives $v_{\rm ph} = 4500\pm500$ km s$^{-1}$ at +50 days. We also observe spectral homogeneity of ultraviolet spectra at +10--12 days for SNe IIP, while variations are evident a week after explosion. Using the expanding photosphere method, from combined analysis of SN 2013ej and SN 2002ap, we estimate the distance to the host galaxy to be $9.0_{-0.6}^{+0.4}$ Mpc, consistent with distance estimates from other methods. Photometric and spectroscopic analysis during the plateau phase, which we estimated to be $94\pm7$ days long, yields an explosion energy of $0.9\pm0.3\times10^{51}$ ergs, a final pre-explosion progenitor mass of $15.2\pm4.2$~M$_\odot$ and a radius of $250\pm70$~R$_\odot$. We observe a broken exponential profile beyond +120 days, with a break point at +$183\pm16$ days. Measurements beyond this break time yield a $^{56}$Ni mass of $0.013\pm0.001$~M$_\odot$.Comment: 29 pages, 23 figures, 15 tables, Published in The Astrophisical Journa

Gender, age and the MBA: An analysis of extrinsic and intrinsic career benefits

Against the background of an earlier UK study, this paper presents the findings of a Canadian based survey of career benefits from the MBA. Results indicate firstly that gender and age interact to influence perceptions of career outcomes (young men gain most in terms of extrinsic benefits of career change and pay), and secondly that both men and women gain intrinsic benefits from the MBA. However, intrinsic benefits vary by gender: men in the study were more likely to say they gained confidence from having a fuller skill set while women were more likely to say they gained confidence from feelings of self worth; men emphasised how they had learned to give up control while women argued that they had gained a ‘voice’ in the organization. The role of the MBA in career self- management and the acquisition of key skills are examined as well as the implications for the design of programmes in meeting the varied need of men and women in different age groups

Decomposing Star Formation and Active Galactic Nucleus with Spitzer Mid-Infrared Spectra: Luminosity Functions and Co-Evolution

We present Spitzer 7-38um spectra for a 24um flux limited sample of galaxies at z~0.7 in the COSMOS field. The detailed high-quality spectra allow us to cleanly separate star formation (SF) and active galactic nucleus (AGN) in individual galaxies. We first decompose mid-infrared Luminosity Functions (LFs). We find that the SF 8um and 15um LFs are well described by Schechter functions. AGNs dominate the space density at high luminosities, which leads to the shallow bright-end slope of the overall mid-infrared LFs. The total infrared (8-1000um) LF from 70um selected galaxies shows a shallower bright-end slope than the bolometrically corrected SF 15um LF, owing to the intrinsic dispersion in the mid-to-far-infrared spectral energy distributions. We then study the contemporary growth of galaxies and their supermassive black holes (BHs). Seven of the 31 Luminous Infrared Galaxies with Spitzer spectra host luminous AGNs, implying an AGN duty cycle of 23+/-9%. The time-averaged ratio of BH accretion rate and SF rate matches the local M_BH-M_bulge relation and the M_BH-M_host relation at z ~ 1. These results favor co-evolution scenarios in which BH growth and intense SF happen in the same event but the former spans a shorter lifetime than the latter. Finally, we compare our mid-infrared spectroscopic selection with other AGN identification methods and discuss candidate Compton-thick AGNs in the sample. While only half of the mid-infrared spectroscopically selected AGNs are detected in X-ray, ~90% of them can be identified with their near-infrared spectral indices.Comment: ApJ Accepted. emulateapj style. 16 pages, 9 figures, 4 table