University of California, Santa Cruz

About: University of California, Santa Cruz is a education organization based out in Santa Cruz, California, United States. It is known for research contribution in the topics: Galaxy & Population. The organization has 15541 authors who have published 44120 publications receiving 2759983 citations. The organization is also known as: UCSC & UC, Santa Cruz.

Developing understanding of the idea of communities of learners

Abstract: The idea of a community of learners is based on the premise that learning occurs as people participate in shared endeavors with others, with all playing active but often asymmetrical roles in sociocultural activity. This contrasts with models of learning that are based on one‐sided notions of learning— either that it occurs through transmission of knowledge from experts or acquisition of knowledge by novices, with the learner or the others (respectively) in a passive role. In this paper, I develop the distinction between the community of learners and one‐sided approaches from the perspective of a theory of learning as participation, and use two lines of research to illustrate the transitions in perspective necessary to understand the idea of communities of learners. One line of research examines differing models of teaching and learning employed by caregivers and toddlers from Guatemalan Mayan and middle‐class European‐American families; the other line of research involves a study of how middle‐class pare...

An Extension of the Blinder-Oaxaca Decomposition Technique to Logit and Probit Models

Abstract: The Blinder-Oaxaca decomposition technique is widely used to identify and quantify the separate contributions of group differences in measurable characteristics, such as education, experience, marital status, and geographical differences to racial and gender gaps in outcomes. The technique cannot be used directly, however, if the outcome is binary and the coefficients are from a logit or probit model. I describe a relatively simple method of performing a decomposition that uses estimates from a logit or probit model. Expanding on the original application of the technique in Fairlie (1999), I provide a more thorough discussion of how to apply the technique, an analysis of the sensitivity of the decomposition estimates to different parameters, and the calculation of standard errors.

Galacti chemical evolution: Hygrogen through zinc

Abstract: Using the output from a grid of 60 Type II supernova models (Woosley & Weaver 1995) of varying mass (11 approx. less than (M/solar mass) approx. less than 40) and metallicity (0, 10(exp -4), 0.01, and 1 solar metallicity), the chemical evolution of 76 stable isotopes, from hydrogen to zinc, is calculated. The chemical evolution calculation employs a simple dynamical model for the Galaxy (infall with a 4 Gyr e-folding timescale onto a exponential dsk and 1/r(exp 2) bulge), and standard evolution parameters, such as a Salpeter initial mass function and a quadratic Schmidt star formation rate. The theoretical results are compared in detail with observed stellar abundances in stars with metallicities in the range -3.0 approx. less than (Fe/H) approx. less than 0.0 dex. While our discussion focuses on the solar neighborhood where there are the most observations, the supernova rates, an intrinsically Galactic quality, are also discussed.

Communicating climate change: history, challenges, process and future directions

Abstract: Since anthropogenic climate change first emerged on the public agenda in the mid-to-late 1980s, public communication of climate change and—more recently—the question of how to communicate it most effectively have witnessed a steep rise. This paper synthesizes what is known, presumed, and still unknown about how to effectively communicate this problem. An introductory historical overview of climate change communication is followed by a discussion of the challenges that communicators face in trying to convey the issue (invisibility of causes, distant impacts, lack of immediacy and direct experience of the impacts, lack of gratification for taking mitigative actions, disbelief in human's global influence, complexity and uncertainty, inadequate signals indicating the need for change, perceptual limits and self-interest). The core of the paper focuses on key aspects of the communication process (purpose and scope of the communication, audience, framing, messages, messengers, modes and channels of communication, and assessing the outcomes and effectiveness of a communication). These elements are placed in relationship to several contextual factors that affect the communication process. The paper concludes with suggestions for future research on climate change communication. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

LSST: From Science Drivers to Reference Design and Anticipated Data Products

Abstract: We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the solar system, exploring the transient optical sky, and mapping the Milky Way. LSST will be a large, wide-field ground-based system designed to obtain repeated images covering the sky visible from Cerro Pachon in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2 field of view, a 3.2-gigapixel camera, and six filters (ugrizy) covering the wavelength range 320–1050 nm. The project is in the construction phase and will begin regular survey operations by 2022. About 90% of the observing time will be devoted to a deep-wide-fast survey mode that will uniformly observe a 18,000 deg2 region about 800 times (summed over all six bands) during the anticipated 10 yr of operations and will yield a co-added map to r ~ 27.5. These data will result in databases including about 32 trillion observations of 20 billion galaxies and a similar number of stars, and they will serve the majority of the primary science programs. The remaining 10% of the observing time will be allocated to special projects such as Very Deep and Very Fast time domain surveys, whose details are currently under discussion. We illustrate how the LSST science drivers led to these choices of system parameters, and we describe the expected data products and their characteristics.