San Francisco State University

About: San Francisco State University is a education organization based out in San Francisco, California, United States. It is known for research contribution in the topics: Population & Planet. The organization has 5669 authors who have published 11433 publications receiving 408075 citations. The organization is also known as: San Francisco State & San Francisco State Normal School.

Rubrics: Tools for Making Learning Goals and Evaluation Criteria Explicit for Both Teachers and Learners

Abstract: Introduction of new teaching strategies often expands the expectations for student learning, creating a parallel need to redefine how we collect the evidence that assures both us and our students that these expectations are in fact being met. The default assessment strategy of the typical large, introductory, college-level science course, the multiple- choice (fixed response) exam, when used to best advantage can provide feedback about what students know and recall about key concepts. Leaving aside the difficulty inherent in designing a multiple-choice exam that captures deeper understandings of course material, its limitations become particularly notable when learning objectives include what students are able to do as well as know as the result of time spent in a course. If we want students to build their skill at conducting guided laboratory investigations, developing reasoned arguments, or communicating their ideas, other means of assessment such as papers, demonstrations (the “practical exam”), other demonstrations of problem solving, model building, debates, or oral presentations, to name a few, must be enlisted to serve as benchmarks of progress and/or in the assignment of grades. What happens, however, when students are novices at responding to these performance prompts when they are used in the context of science learning, and faculty are novices at communicating to students what their expectations for a high-level performance are? The more familiar terrain of the multiple-choice exam can lull both students and instructors into a false sense of security about the clarity and objectivity of the evaluation criteria (Wiggins, 1989 ) and make these other types of assessment strategies seem subjective and unreliable (and sometimes downright unfair) by comparison. In a worst-case scenario, the use of alternatives to the conventional exam to assess student learning can lead students to feel that there is an implicit or hidden curriculum—the private curriculum that seems to exist only in the mind's eye of a course instructor. Use of rubrics provides one way to address these issues. Rubrics not only can be designed to formulate standards for levels of accomplishment and used to guide and improve performance but also they can be used to make these standards clear and explicit to students. Although the use of rubrics has become common practice in the K–12 setting (Luft, 1999 ), the good news for those instructors who find the idea attractive is that more and more examples of the use of rubrics are being noted at the college and university level, with a variety of applications (Ebert-May, undated; Ebert-May et al., 1997 ; Wright and Boggs, 2002 ; Moni et al., 2005 ; Porter, 2005 ; Lynd-Balta, 2006 ).

Trichodesmium – a widespread marine cyanobacterium with unusual nitrogen fixation properties

Abstract: The last several decades have witnessed dramatic advances in unfolding the diversity and commonality of oceanic diazotrophs and their N2-fixing potential. More recently, substantial progress in diazotrophic cell biology has provided a wealth of information on processes and mechanisms involved. The substantial contribution by the diazotrophic cyanobacterial genus Trichodesmium to the nitrogen influx of the global marine ecosystem is by now undisputable and of paramount ecological importance, while the underlying cellular and molecular regulatory physiology has only recently started to unfold. Here, we explore and summarize current knowledge, related to the optimization of its diazotrophic capacity, from genomics to ecophysiological processes, via, for example, cellular differentiation (diazocytes) and temporal regulations, and suggest cellular research avenues that now ought to be explored.

Resurgence and trans-series in Quantum Field Theory: the $\mathbb{C}{{\mathbb{P}}^{N-1 }}$ model

Abstract: This work is a step towards a non-perturbative continuum definition of quantum field theory (QFT), beginning with asymptotically free two dimensional non-linear sigma-models, using recent ideas from mathematics and QFT. The ideas from mathematics are resurgence theory, the trans-series framework, and Borel-Ecalle resummation. The ideas from QFT use continuity on ${{\mathbb{R}}^1}\times \mathbb{S}_L^1$ , i.e., the absence of any phase transition as N → ∞ or rapid-crossovers for finite-N, and the small-L weak coupling limit to render the semi-classical sector well-defined and calculable. We classify semi-classical configurations with actions 1/N (kink-instantons), 2/N (bions and bi-kinks), in units where the 2d instanton action is normalized to one. Perturbation theory possesses the IR-renormalon ambiguity that arises due to non-Borel summability of the large-orders perturbation series (of Gevrey-1 type), for which a microscopic cancellation mechanism was unknown. This divergence must be present because the corresponding expansion is on a singular Stokes ray in the complexified coupling constant plane, and the sum exhibits the Stokes phenomenon crossing the ray. We show that there is also a non-perturbative ambiguity inherent to certain neutral topological molecules (neutral bions and bion-anti-bions) in the semiclassical expansion. We find a set of “confluence equations” that encode the exact cancellation of the two different type of ambiguities. There exists a resurgent behavior in the semi-classical trans-series analysis of the QFT, whereby subleading orders of exponential terms mix in a systematic way, canceling all ambiguities. We show that a new notion of “graded resurgence triangle” is necessary to capture the path integral approach to resurgence, and that graded resurgence underlies a potentially rigorous definition of general QFTs. The mass gap and the Θ angle dependence of vacuum energy are calculated from first principles, and are in accord with large-N and lattice results.