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.

International reserves: precautionary versus mercantilist views, theory and evidence

Abstract: This paper tests the importance of precautionary and mercantilist motives in accounting for the hoarding of international reserves by developing countries, and provides a model that quantifies the welfare gains from optimal management of international reserves. While the variables associated with the mercantilist motive are statistically significant, their economic importance in accounting for reserve hoarding is close to zero and is dwarfed by other variables. Overall, the empirical results are in line with the precautionary demand. The effects of financial crises have been localized, increasing reserve hoarding in the aftermath of crises mostly in countries located in the affected region, but not in other regions. We also investigate the micro foundation of precautionary demand, extending Diamond and Dybvig (1983)’s model to an open, emerging market economy where banks finance long-term projects with short-term deposits. We identify circumstances that lead to large precautionary demand for international reserves, providing self-insurance against the adverse output effects of sudden stop and capital flight shocks. This would be the case if premature liquidation of long-term projects is costly, and the economy is de-facto integrated with the global financial system, hence sudden stops and capital flight may reduce deposits sharply. We show that the welfare gain from the optimal management of international reserves is of a first-order magnitude, reducing the welfare cost of liquidity shocks from a first-order to a second-order magnitude.

Computational thinking for youth in practice

Abstract: Computational thinking (CT) has been described as the use of abstraction, automation, and analysis in problem-solving [3]. We examine how these ways of thinking take shape for middle and high school youth in a set of NSF-supported programs. We discuss opportunities and challenges in both in-school and after-school contexts. Based on these observations, we present a "use-modify-create" framework, representing three phases of students' cognitive and practical activity in computational thinking. We recommend continued investment in the development of CT-rich learning environments, in educators who can facilitate their use, and in research on the broader value of computational thinking.

The segue stellar parameter pipeline. i. description and comparison of individual methods

Abstract: We describe the development and implementation of the Sloan Extension for Galactic Exploration and Understanding (SEGUE) Stellar Parameter Pipeline (SSPP) The SSPP is derived, using multiple techniques, radial velocities, and the fundamental stellar atmospheric parameters (effective temperature, surface gravity, and metallicity) for AFGK-type stars, based on medium-resolution spectroscopy and ugriz photometry obtained during the course of the original Sloan Digital Sky Survey (SDSS-I) and its Galactic extension (SDSS-II/SEGUE) The SSPP also provides spectral classification for a much wider range of stars, including stars with temperatures outside the window where atmospheric parameters can be estimated with the current approaches This is Paper I in a series of papers on the SSPP; it provides an overview of the SSPP, and tests of its performance using several external data sets Random and systematic errors are critically examined for the current version of the SSPP, which has been used for the sixth public data release of the SDSS (DR-6)

Double-Sided CdS and CdSe Quantum Dot Co-Sensitized ZnO Nanowire Arrays for Photoelectrochemical Hydrogen Generation

Abstract: We report the design and characterization of a novel double-sided CdS and CdSe quantum dot cosensitized ZnO nanowire arrayed photoanode for photoelectrochemical (PEC) hydrogen generation. The double-sided design represents a simple analogue of tandem cell structure, in which the dense ZnO nanowire arrays were grown on an indium−tin oxide substrate followed by respective sensitization of CdS and CdSe quantum dots on each side. As-fabricated photoanode exhibited strong absorption in nearly the entire visible spectrum up to 650 nm, with a high incident-photon-to-current-conversion efficiency (IPCE) of ∼45% at 0 V vs Ag/AgCl. On the basis on a single white light illumination of 100 mW/cm2, the photoanode yielded a significant photocurrent density of ∼12 mA/cm2 at 0.4 V vs Ag/AgCl. The photocurrent and IPCE were enhanced compared to single quantum dot sensitized structures as a result of the band alignment of CdS and CdSe in electrolyte. Moreover, in comparison to single-sided cosensitized layered structures, ...

Stochastic games with lossy channels

Abstract: We consider turn-based stochastic games on infinite graphs induced by game probabilistic lossy channel systems (GPLCS), the game version of probabilistic lossy channel systems (PLCS). We study games with Buchi (repeated reachability) objectives and almost-sure winning conditions. These games are pure memoryless determined and, under the assumption that the target set is regular, a symbolic representation of the set of winning states for each player can be effectively constructed. Thus, turn-based stochastic games on GPLCS are decidable. This generalizes the decidability result for PLCS-induced Markov decision processes in [10].