Double codes: Community radio in Bolivia

Abstract

In this article, we report results of interviews conducted with 20 informants at 8 community radio stations across the major regions of Bolivia. We explore the activism and community practices that have energized Bolivian community radio stations over a sustained period. We are in particular interested in the bottom-up networking by these community stations to interlink with each other. These networks actualize the goals of horizontal and participatory communication called for by Latin American theorists. We seek to learn from these endeavors and also contribute to their continued flourishing by analyzing potential threats to them.     

The dynamics and stability of lubricating oil films during droplet transport by electrowetting in microfluidic devices

The operation of digital microfluidic devices with water droplets manipulated by electrowetting is critically dependent on the static and dynamic stability and lubrication properties of the oil films that separate the droplets from the solid surfaces. The factors determining the stability of the films and preventing surface fouling in such systems are not yet thoroughly understood and were experimentally investigated in this study. The experiments were performed using a standard digital microfluidic cartridge in which water droplets enclosed in a thin, oil-filled gap were transported over an array of electrodes. Stable, continuous oil films separated the droplets from the surfaces when the droplets were stationary. During droplet transport, capillary waves formed in the films on the electrode surfaces as the oil menisci receded. The waves evolved into dome-shaped oil lenses. Droplet deformation and oil displacement caused the films at the surface opposite the electrode array to transform into dimples of oil trapped over the centers of the droplets. Lower actuation voltages were associated with slower film thinning and formation of fewer, but larger, oil lenses. Lower ac frequencies induced oscillations in the droplets that caused the films to rupture. Films were also destabilized by addition of surfactants to the oil or droplet phases. Such a comprehensive understanding of the oil film behavior will enable more robust electrowetting-actuated lab-on-a-chip devices through prevention of loss of species from droplets and contamination of surfaces at points where films may break.     

Examining the relationship among student perception of support, course satisfaction, and learning outcomes in online learning

Support for student learning is a key element in optimizing student learning experiences in any learning environment and its importance has been widely discussed. This study looked at student support, particularly in the course context, focusing mainly on guidance provided to students within a course. Three categories of support were identified and used for the purpose of this study: instructional, peer, and technical support. A total of 110 students completed an online survey on students' perceptions of support and course satisfaction in an undergraduate online course at a large southeastern university. The results showed perceived support was significantly related to their overall satisfaction of the online course. The findings of this study suggest that teachers should communicate what types of support are available to students and provide an easy way of accessing and taking advantage of the support.     

Archimedes: Bathtub academicpar excellence

Stability and control of floating bodies is a major aspect of navigation from ancient to modern times. It is indeed remarkable that Archimedean concepts continue to guide watercraft designers even after 2200 years! Extending Euclidean concept to solids, Archimedes solved the problem of a paraboloid floating stably but with its base inclined to the water surface. Here, we revisit Archimedes and present stability maps (A-maps) for paraboloid, solid cone and a prism. For a specific combination of geometry and specific gravity, these A-maps predict whether a solid floats vertically or in a tilted fashion; or, whether it is partially submerged.     

Information determinism: The consequences of the faith in information

We identify and examine the assumption of information determinism that is commonplace in policy arenas: that mere access to the “right information” will precipitate desired actions. Our analysis focuses on implications of information determinism in three cases: California disaster response plans in the 1980s, an Indian development project in the 1990s, and an education project directed at the Global South in the 2000s. Our analyses shows that planning based on information deterministic assumptions tends to overlook the sociomaterial circumstances of information production and circulation, including how social structures and materiality shape information in practice. Further, they imbue what we call “information” with the agency to bring about change. While we do not deny that “information” can be useful, we argue that policy needs to move away from information deterministic thinking and its singular focus on information access to address the needs of marginalized and vulnerable populations.     

Spintronics

Spintronics is creating new excitement in the scientific world. In Part 1 of this two-part article, we will deal in an elementary fashion with the principles of spintronics. R Srinivasan was the former Director of Centre for Advanced Technology, Indore and at present a Visiting Professor with the Laser-Cooling Group, Raman Research Institute.     

Adaptive Filtering of Newswire Stories using Two-Level Clustering

Adaptive filtering of news is an area of information retrieval gaining substantial interest as services become more available on the Internet. This paper reports on a number of experiments involving a two-level clustering approach using a variety of techniques including threshold adaptation, topic vocabulary adaptation and both noun phrase and named entity adaptation. Our goal in this exploratory research is to empirically compare alternative configurations of our filtering approach that will allow us to better understand the relative value of the component subsystems.