Iterated gain-based stochastic filters for dynamic system identification

We propose a novel form of nonlinear stochastic filtering based on an iterative evaluation of a Kalman-like gain matrix computed within a Monte Carlo scheme as suggested by the form of the parent equation of nonlinear filtering (Kushner–Stratonovich equation) and retains the simplicity of implementation of an ensemble Kalman filter (EnKF). The numerical results, presently obtained via EnKF-like simulations with or without a reduced-rank unscented transformation, clearly indicate remarkably superior filter convergence and accuracy vis-à-vis most available filtering schemes and eminent applicability of the methods to higher dimensional dynamic system identification problems of engineering interest.     

Books for the hospital emergency service

This is a list of books that should be available in either the hospital emergency room or the medical library. The forty-nine books listed are divided into the following categories: General, Surgery and Trauma, Burns, Cardiology, Dentistry, Disaster Medicine, First Aid, Geriatrics, Obstetrics, Pediatrics, Psychiatry, Toxicology, and Transportation. An asterisk has been placed before twelve books that are particularly recommended for the hospital emergency room as well as the medical library. The latest edition is given for each book, and, unless otherwise noted, each has been annotated by one of the authors.     

Leveling the playing field in ICT design: Transcending knowledge roles by balancing division and privileging of knowledges

Abstract

This article develops a conceptual model of users’ and designers’ knowledge roles in the information and communication technology design process. The “ideal” center at the intersection of the axes for division of knowledge work and privileging of knowledges represents a balanced distribution of knowledge work between users and designers and an avoidance of privileging either group over the other. The article then applies this model to analyses of the design process for six video games wherein the knowledges of Indigenous peoples in North America were mobilized. It concludes by discussing implications for research and design practice, particularly for broadening the participation and self-articulation of marginalized groups.     

A large-scale donor attempt to improve educational status of the poor and household income distribution: The experience of PEDC in Vietnam

In 2003, donors combined together in Vietnam to support the provision of quality primary schooling for 226 disadvantaged districts (about a third of the country). US$160 million was invested in infrastructure, materials and training across the 226 districts. The programme has been commended by donors and received good press inside Vietnam. Comparison of achievement surveys in 2001 and 2007 showed, however, that there had been a decline in performance in the targeted districts. This article explores various hypotheses as to how this could have happened; and in particular the increasing amounts spent by better-off households on their children's education.     

Spectral and graph-theoretic bounds on steady-state-probability estimation performance for an ergodic Markov chain

Motivated by the wide application of Markov-chain steady-state-probability estimation, we pursue a spectral and graph-theoretic performance analysis of a classical estimator for steady-state probabilities here. Specifically, we connect a performance measure to estimate the structure of the underlying graph defined on the Markov-chain's state transitions. To do so, (1) we present a series of upper bounds on the performance measure in terms of the subdominant eigenvalue of the state transition matrix, which is closely connected with the graph structure; (2) as an illustration of the graph-theoretic analysis, we then relate the subdominant eigenvalue to the connectivity of the graph, including for the strong-connectivity case and the weak-link case. We also apply the results to characterize estimation in Markov chains with rewards.     

Amplitude-modulated sinusoidal microchannels for observing adaptability in C. elegans locomotion

In this paper, we present a movement-based assay to observe adaptability in Caenorhabditis elegans locomotion behavior. The assay comprises a series of sinusoidal microchannels with a fixed wavelength and modulating (increasing or decreasing) amplitude. The channel width is comparable to the body diameter of the organism. Worms are allowed to enter the channel from the input port and migrate toward the output port. Within channel sections that closely match the worm's natural undulations, the worm movement is relatively quick and steady. As the channel amplitude increases or decreases along the device, the worm faces difficulty in generating the propulsive thrust, begins to slow down and eventually fails to move forward. A set of locomotion parameters (i.e., average forward velocity, number and duration of stops, range of contact angle, and cut-off region) is defined for worm locomotion in modulated sinusoidal channels and extracted from the recorded videos. The device is tested on wild-type C. elegans (N2) and two mutants (lev-8 and unc-38). We anticipate this passive, movement-based assay can be used to screen nematodes showing difference in locomotion phenotype.     

Bromo-oxidation reaction in enzyme-entrapped alginate hollow microfibers

In this article, the authors present the fabrication of an enzyme-entrapped alginate hollow fiber using a microfluidic device. Further use of enzyme-entrapped alginate hollow fibers as a biocatalytic microchemical reactor for chemical synthesis is also deliberated in this article. To ensure that there is no enzyme leaching from the fiber, fiber surfaces were coated with chitosan. To confine the mobility of reactants and products within the porous hollow fibers the entire fibers were embedded into a transparent polydimethylsiloxane (PDMS) matrix which also works as a support matrix. A vanadium-containing bromoperoxidase enzyme isolated from Corallina confusa was used as a model enzyme to demonstrate the use of these alginate hollow-fiber reactors in bromo-oxidation of phenol red to bromophenol blue at different dye flow rates. Stability of the entrapped enzyme at different temperatures and the effect of the chitosan coating on the reaction conversion were also studied. It was observed that molecules as big as 27 kDa can be retained in the matrix after coating with chitosan while molecules with molecular-weight of around 378 Da can still diffuse in and out of the matrix. The kinetic conversion rate in this microfluidic bioreactor was more than 41-fold faster when compared with the standard test-tube procedure.     

Promoting Inquiry-Based Teaching in Laboratory Courses: Are We Meeting the Grade?

Over the past decade, repeated calls have been made to incorporate more active teaching and learning in undergraduate biology courses. The emphasis on inquiry-based teaching is especially important in laboratory courses, as these are the courses in which students are applying the process of science. To determine the current state of research on inquiry-based teaching in undergraduate biology laboratory courses, we reviewed the recent published literature on inquiry-based exercises. The majority of studies in our data set were in the subdisciplines of biochemistry, cell biology, developmental biology, genetics, and molecular biology. In addition, most exercises were guided inquiry, rather than open ended or research based. Almost 75% of the studies included assessment data, with two-thirds of these studies including multiple types of assessment data. However, few exercises were assessed in multiple courses or at multiple institutions. Furthermore, assessments were rarely based on published instruments. Although the results of the studies in our data set show a positive effect of inquiry-based teaching in biology laboratory courses on student learning gains, research that uses the same instrument across a range of courses and institutions is needed to determine whether these results can be generalized.