Using Concept Inventories to Measure Understanding

Measuring understanding is notoriously difficult. Indeed, in formulating learning outcomes the word “understanding” is usually avoided, but in the sciences, developing understanding is one of the main aims of instruction. Scientific knowledge is factual, having been tested against empirical observation and experimentation, but knowledge of facts alone is not enough. There are also models and theories containing complex ideas and inter-relationships that must be understood, and considerable attention has been devoted across a range of scientific disciplines to measuring understanding. This case study will focus on one of the main tools employed: the concept inventory and in particular the Force Concept Inventory. The success of concept inventories in physics has spawned concept inventories in chemistry, biology, astronomy, materials science and maths, to name a few. We focus here on the FCI, ask how useful concept inventories are for evaluating learning gains. Finally, we report on recent work by the authors to extend conceptual testing beyond the multiple-choice format

Lasers for Satellite Uplinks and Downlinks

The article of record as published may be found at http://dx.doi.org/10.3390/sci2030071The use of Light Amplification by Stimulated Emission of Radiation (i.e., LASERs or lasers) by the U.S. Department of Defense is not new and includes laser weapons guidance, laser-aided measurements, even lasers as weapons (e.g., Airborne Laser). Lasers in support of telecommunications is also not new. The use of laser light in fiber optics shattered thoughts on communications bandwidth and throughput. Even the use of lasers in space is no longer new. Lasers are being used for satellite-to-satellite crosslinking. Laser communication can transmit orders-of-magnitude more data using orders-of-magnitude less power and can do so with minimal risk of exposure to the sending and receiving terminals. What is new is using lasers as the uplink and downlink between the terrestrial segment and the space segment of satellite systems. More so, the use of lasers to transmit and receive data between moving terrestrial segments (e.g., ships at sea, airplanes in flight) and geosynchronous satellites is burgeoning. This manuscript examines the technological maturation of employing lasers as the signal carrier for satellite communications linking terrestrial and space systems. The purpose of the manuscript is to develop key performance parameters (KPPs) to inform U.S. Department of Defense initial capabilities documents (ICDs) for near-future satellite acquisition and development. By appreciating the history and technological challenges of employing lasers rather than traditional radio frequency sources for satellite uplink and downlink signal carrier, this manuscript recommends ways for the U.S. Department of Defense to employ lasers to transmit and receive high bandwidth, large-throughput data from moving platforms that need to retain low probabilities of detection, intercept, and exploitation (e.g., carrier battle group transiting to a hostile area of operations, unmanned aerial vehicle collecting over adversary areas). The manuscript also intends to identify commercial sector early-adopter fields and those fields likely to adapt to laser employment for transmission and receipt.U.S. Air Forc

Detroit’s bankruptcy settlement will not solve the city’s problems

In December, a federal judge ruled that the city of Detroit’s bankruptcy proceedings could continue, and it is now likely to take years for the city to settle its creditors’ claims. Gary Sands, Laura A. Reese, and Mark Skidmore look at Detroit’s recent history which has been characterized by deindustrialization and depopulation, and public mismanagement and corruption. They argue that even after the city’s bankruptcy is concluded, Detroit’s underlying fundamental structural weaknesses mean that its problems are unlikely to go away

The role of attenuated astrocyte activation in infantile neuronal Ceroid Lipofuscinosis

Infantile neuronal ceroid lipofuscinosis (INCL) is an inherited neurodegenerative disorder affecting the CNS during infancy. INCL is caused by mutations in the CLN1 gene that leads to a deficiency in the lysosomal hydrolase, palmitoyl protein thioesterase (PPT1). A murine model of INCL, the PPT1(−/−) mouse, is an accurate phenocopy of the human disease. The first pathological change observed in the PPT1(−/−) brain is regional areas of GFAP upregulation, which predicts future areas of neurodegeneration. We hypothesized that preventing GFAP upregulation in reactive astrocytes will alter the CNS disease. To test this hypothesis, we generated mice simultaneously carrying null mutations in the GFAP, Vimentin, and PPT1 genes (GFAP(−/−)Vimentin(−/−)PPT1(−/−)). Although the clinical and pathological features of the GFAP(−/−)Vim(−/−)PPT1(−/−) mice are similar to INCL, the disease appears earlier and progresses more rapidly. One mechanism underlying this accelerated phenotype is a profound neuroinflammatory response within the CNS. Thus, our data identify a protective role for intermediate filament upregulation during astrocyte activation in INCL, a model of chronic neurodegeneration

Property Tax Delinquency - Social Contract in Crisis: The Case of Detroit

In this paper we develop a theoretical model of the individual decision to become delinquent on one’s property tax payments. We then apply the model to the City of Detroit, Michigan, USA, where the city is in the midst of bankruptcy proceedings, and a rate of property tax delinquency of 48 percent, resulting in uncollected tax revenues of about 20 percent. We use detailed parcellevel data for Detroit to evaluate the factors that affect both the probability that a property owner is tax delinquent and, conditional upon delinquency, the magnitude of the delinquency. Our estimates show that properties that have lower value, longer police response times, are nonhomestead (non-owner occupied residential properties), have a higher statutory tax rate, have a higher assessed value relative to sales price, are owned by a financial institution or by a Detroit resident, are delinquent on water bills, and for which the probability of enforcement is low are more likely to be tax delinquent These findings can be used to inform policies targeted at improving tax compliance within the City

Bone marrow transplantation alters the tremor phenotype in the murine model of globoid-cell leukodystrophy

Tremor is a prominent phenotype of the twitcher mouse, an authentic genetic model of Globoid-Cell Leukodystrophy (GLD, Krabbe’s disease). In the current study, the tremor was quantified using a force-plate actometer designed to accommodate low-weight mice. The actometer records the force oscillations caused by a mouse’s movements, and the rhythmic structure of the force variations can be revealed. Results showed that twitcher mice had significantly increased power across a broad band of higher frequencies compared to wildtype mice. Bone marrow transplantation (BMT), the only available therapy for GLD, worsened the tremor in the twitcher mice and induced a measureable alteration of movement phenotype in the wildtype mice. These data highlight the damaging effects of conditioning radiation and BMT in the neonatal period. The behavioral methodology used herein provides a quantitative approach for assessing the efficacy of potential therapeutic interventions for Krabbe’s disease