3,287 research outputs found

    Engineering works and the tidal Chesapeake

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    The tidal tributaries of the ocean and coastal areas of the mid-Atlantic region and the ecological significance of engineering projects are discussed. The effects of engineering works on maritime environments and resources, with the Chesapeake Bay as the area of prime interest are examined. Significant engineering projects, both actual and proposed, are described. The conflict of navigational demands and maintenance of an estuarine environment for commercial and sport fishing and recreation is described. Specific applications of remote sensors for analyzing ecological conditions of the bay are included

    The Globular Cluster Populations of Giant Galaxies: Mosaic Imaging of Five Moderate-Luminosity Early-Type Galaxies

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    This paper presents results from wide-field imaging of the globular cluster (GC) systems of five intermediate-luminosity (M_V ~-21 to -22) early-type galaxies. The aim is to accurately quantify the global properties of the GC systems by measuring them out to large radii. We obtained BVR imaging of four lenticular galaxies (NGC 5866, NGC 4762, NGC 4754, NGC 3384) and one elliptical galaxy (NGC 5813) using the KPNO 4m telescope and MOSAIC imager and traced the GC population to projected galactocentric radii ranging from ~20 kpc to 120 kpc. We combine our imaging with Hubble Space Telescope data to measure the GC surface density close to the galaxy center. We calculate the total number of GCs (N_GC) from the integrated radial profile and find N_GC = 340 +/- 80 for NGC 5866, N_GC = 2900 +/- 400 for NGC 5813, N_GC = 270 +/- 30 for NGC 4762, N_GC = 115 +/- 15$ for NGC 4754, and N_GC = 120 +/- 30 for NGC 3384. The measured GC specific frequencies are S_N between 0.6 and 3.6 and T in the range 0.9 to 4.2. These values are consistent with the mean specific frequencies for the galaxies' morphological types found by our survey and other published data. Three galaxies (NGC 5866, NGC 5813, NGC 4762) had sufficient numbers of GC candidates to investigate color bimodality and color gradients in the GC systems. NGC 5813 shows strong evidence (>3 sigma) for bimodality and a B-R color gradient resulting from a more centrally concentrated red (metal-rich) GC subpopulation. We find no evidence for statistically significant color gradients in the other two galaxies.Comment: 61 pages, 21 figures, 11 tables. Accepted for publication in The Astronomical Journa

    Southern Chesapeake Bay water color and circulation analysis

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    There are no author-identified significant results in this report

    Active Techniques Implemented in an Introductory Signal Processing Course to Help Students Achieve Higher Levels of Learning.

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    Holding students to high standards and assessing, measuring and evaluating their learning with challenging, authentic problems in the midterm and final exams is the goal of the professors who teach core signal processing concepts. However, the heavy reliance of these subjects on mathematics makes it difficult for students to genuinely grasp the concepts and relate to a conceptual framework. Specifically, analyzing the signals and the functionality of systems in Fourier domain; separating the system level analysis from signal level analysis; and understanding how they are related in time domain and frequency domain are among the most challenging concepts. Students’ lower grades observed over past years in the introductory signal processing course exposed a potential disconnect between the actual level of learning and the high expectations set by the professors. In this paper, we present the active learning techniques that we implemented in one of the summer session offerings of this course in our department. The research explored Peer Instruction, pre-class reading quizzes and post-lecture quizzes. In addition to the mid and end of the quarter survey results, the comparison analysis of the grades students achieved in the active learning integrated course in the second summer session and the standard course offered in first summer session is discussed. According to our results, the developed techniques helped students in the active classroom perform significantly better than their peers participating in standard lectures when tested by challenging questions in their exams

    Dissolving the Conflict: Why the Church Should Be More Open to Evolution

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    Evolution can be very controversial, but I don\u27t think that this needs to be the case. Having grown up in the south, in a Southern Baptist Church, I saw that evolution was always viewed as anti-theistic and treated like a trick from the devil. Many of the people that I went to church with believed that the world was only six thousand years old and would defend that opinion wholeheartedly, but my parents taught us that the world was very old. They were not strictly evolutionists but they believed that it very well could have happened if God chose to use that method, so from an early age I felt this tension between science (what my parents had taught me about it) and the beliefs of my church. Because of these things, I decided that for my senior thesis, I would continue my research and try to produce a short, but yet concise explanation of evolution and how a Christian can still believe both the Bible and evolutionary theory

    The Luminosity Function and Color-Magnitude Diagram of the Globular Cluster M12

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    In this paper we present the V and I luminosity functions and color-magnitude diagrams derived from wide-field (23 arcmin by 23 arcmin) BVI photometry of the intermediate metallicity ([Fe/H]=-1.3) Galactic globular cluster M12. Using observed values (and ranges of values) for the cluster metallicity, reddening, distance modulus, and age we compare these data to recent alpha-enhanced stellar evolution models for low mass metal-poor stars. We describe several methods of making comparisons between theoretical and observed luminosity functions in order to isolate the evolutionary timescale information the luminosity functions contain. We find no significant evidence of excesses of stars on the red giant branch, although the morphology of the subgiant branch in the observed luminosity function does not match theoretical predictions in a satisfactory way. Current uncertainties in Teff-color transformations (and possibly also in other physics inputs to the models) make more detailed conclusions about the subgiant branch morphology impossible. Given the recent constraints on cluster ages from the WMAP experiment (Spergel et al. 2003), we find that good fitting models that do not include He diffusion (both color-magnitude diagrams and luminosity functions) are too old (by approximately 1-2 Gyr) to adequately represent the cluster luminosity function. The inclusion of helium diffusion in the models provides an age reduction (compared to non-diffusive models) that is consistent with the age of the universe being 13.7+/-0.2 Gyr (Bennett et al. 2003)
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