University of California, Santa Barbara

About: University of California, Santa Barbara is a education organization based out in Santa Barbara, California, United States. It is known for research contribution in the topics: Population & Laser. The organization has 30281 authors who have published 80852 publications receiving 4626827 citations. The organization is also known as: UC Santa Barbara & UCSB.

The credibility of volunteered geographic information

Abstract: The proliferation of information sources as a result of networked computers and other interconnected devices has prompted significant changes in the amount, availability, and nature of geographic information. Among the more significant changes is the increasing amount of readily available volunteered geographic information. Although volunteered information has fundamentally enhanced geographic data, it has also prompted concerns with regard to its quality, reliability, and overall value. This essay situates these concerns as issues of information and source credibility by (a) examining the information environment fostering collective information contribution, (b) exploring the environment of information abundance, examining credibility and related notions within this environment, and leveraging extant research findings to understand user-generated geographic information, (c) articulating strategies to discern the credibility of volunteered geographic information (VGI), including relevant tools useful in this endeavor, and (d) outlining specific research questions germane to VGI and credibility.

Exact differential equation for the density and ionization energy of a many-particle system

Abstract: The present investigation is concerned with relations studied by Hohenberg and Kohn (1964) and Kohn and Sham (1965). The properties of a ground-state many-electron system are determined by the electron density. The correct differential equation for the density, as dictated by density-functional theory, is presented. It is found that the ground-state density n of a many-electron system obeys a Schroedinger-like differential equation which may be solved by standard Kohn-Sham programs. Results are connected to the traditional exact Kohn-Sham theory. It is pointed out that the results of the current investigations are readily extended to spin-density functional theory.

Toward an Understanding of Definitions and Measures of School Engagement and Related Terms

Abstract: This article provides an overview of definitions and measures related to school engagement. The intent herein, is to explore the construct and measurement of school engagement and related terms and provide a summary of previous literature, in an effort to offer a foundation to advance related scholarship and practice. Previous articles exploring school engagement, school bonding, and other associated terms (e.g., school attachment, school commitment, motivation) include a variety of definitions and measures. Items used in previous research addressing school engagement and related terms were classified into five contexts: a) academic performance, b) classroom behavior, c) extracurricular involvement, d) interpersonal relationships, and e) school community. Based on this review, it is suggested that school engagement is a multifaceted construct that includes affective, behavioral, and cognitive dimensions. Conceptualizing school engagement as a multifaceted construct has implications for both research and practice.

Metal-Free Atom Transfer Radical Polymerization

Abstract: Overcoming the challenge of metal contamination in traditional ATRP systems, a metal-free ATRP process, mediated by light and catalyzed by an organic-based photoredox catalyst, is reported. Polymerization of vinyl monomers are efficiently activated and deactivated with light leading to excellent control over the molecular weight, polydispersity, and chain ends of the resulting polymers. Significantly, block copolymer formation was facile and could be combined with other controlled radical processes leading to structural and synthetic versatility. We believe that these new organic-based photoredox catalysts will enable new applications for controlled radical polymerizations and also be of further value in both small molecule and polymer chemistry.