Not driving alone: Commuting in the Twenty-first century

This paper investigates recent commuting trends in American workers. Unlike most studies of commuting that rely on Census data, this study utilizes the unique American Time Use Survey to detail the complex commuting patterns of modern-day workers. The data confirm what has been suspected, that incidence of driving alone has decreased substantially in recent years while carpooling has rebounded. The results from the multi-nominal logistic estimation of workers' commuting choices yield support for both the traditional economic determinants as well as for the newer, socio-economic factors. In addition to the cost savings, many commuters appear to value the social aspect of carpooling. Surprisingly, there is little evidence that the need for autonomy plays much of a factor in explaining workerÕs choice of the journey to work. The estimated short-run elasticity of carpooling with respect to real gas prices appears to be quite high and largely accounts for the significant decline in the incidence of driving alone.Ride sharing, carpooling, commuting, gasoline process, social capital

On the Struggle To Attain Universal Competence in a Complex Skill: The Case of a Senior Capstone Experience

Seventeen years ago, a blue-ribbon committee of economists asserted that the “ideal” program for an economics major should include “a capstone experience, whereby students apply their knowledge and skills in creative and systematic ways through research and writing.” (Seigfried, Bartlett, Hansen, Kelley, McCloskey, and Tietenberg (1991)) Yet we are not aware of a data-driven assessment of an implemented senior capstone experience in the economics education literature. We have been experimenting with a senior capstone experience – based on research and writing – for more than a decade. In this paper we describe the history of our senior capstone experience, and provide a data-driven assessment of student performance in this experience. Our primary objective for this senior capstone has been to create a system that will result in all of our majors writing a competent senior thesis. In other words, we want to attain universal competence in a complex skill. This simple objective has, however, been very difficult to achieve. We will argue that undesired variation in student motivation has been our primary obstacle in attaining universal competence.

Red Cities, Blue Cities: Creativity, Growth and Politics

The 2006 Congressional elections seemed to be about change, as well as the war in Iraq. The 2008 Presidential election, though only at the primary stage, seems to be about change as well as the war in Iraq and the faltering economy. What is the force behind Americans wanting “change?” Is it simply frustration or is it because of important changes in the economy and the demography of the United States? In his 2002 book, Richard Florida looked at one of those changes and developed a “creativity index” measuring the existence of creative people, economic activity, and cultural tolerance for Metropolitan Statistical Areas in the U.S. This study looks at the connection between the rise of the creative class, economic growth and voting patterns. We find that more creative metropolitan areas grow faster on average and creative areas are more likely to have voted Democratic in the past. Even after controlling for union membership, the presence of creative people explains how metropolitan areas voted in the 2004 Presidential election, hinting at one force behind Americans’ desire for political change.

Active Transport, Public Transportation, and Obesity in Metropolitan Areas of the United States.

There is a well established relationship between exercise and weight in individuals. Recently, relationships between less urban sprawl and more leisure exercise and between certain urban characteristics usually associated with less sprawl and exercise for transportation have been found. This paper completes the less-sprawl-more exercise for transportation-lower weight sequence by finding that counties in metropolitan areas where more people complete their journey to work by walking, biking, or taking public transportation have fewer people who are overweight.

Detection of the Three Kunitz-Type Single Domains of Membrane-Bound Tissue Factor Pathway Inhibitor (TFPI) by Flow Cytometry

Peer Reviewe

Microarchitectural Security of AWS Firecracker VMM for Serverless Cloud Platforms

Firecracker is a virtual machine manager (VMM) built by Amazon Web Services (AWS) for serverless cloud platforms, services that run code for end users on a per-task basis, automatically managing server infrastructure. Firecracker provides fast and lightweight VMs and promises a combination of the speed of containers, typically used to isolate small tasks, and the security of VMs, which tend to provide greater isolation at the cost of performance. This combination of security and efficiency, AWS claims, makes it not only possible but safe to run thousands of user tasks from different users on the same hardware, with the host system frequently switching between active tasks. Though AWS states that microarchitectural attacks are included in their threat model, this class of attacks directly relies on shared hardware, just as the scalability of serverless computing relies on sharing hardware between unprecedented numbers of users. In this work, we investigate how secure Firecracker is against microarchitectural attacks. First, we review Firecracker's stated isolation model and recommended best practices for deployment, identify potential threat models for serverless platforms, and analyze potential weak points. Then, we use microarchitectural attack proof-of-concepts to test the isolation provided by Firecracker and find that it offers little protection against Spectre or MDS attacks. We discover two particularly concerning cases: 1) a Medusa variant that threatens Firecracker VMs but not processes running outside them, and is not mitigated by defenses recommended by AWS, and 2) a Spectre-PHT variant that remains exploitable even if recommended countermeasures are in place and SMT is disabled in the system. In summary, we show that AWS overstates the security inherent to the Firecracker VMM and provides incomplete guidance for properly securing cloud systems that use Firecracker.Comment: 14 pages, 5 figures, 4 table

Decadal assessment of sperm whale site-specific abundance trends in the northern Gulf of Mexico using passive acoustic data

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Li, K., Sidorovskaia, N. A., Guilment, T., Tang, T., & Tiemann, C. O. Decadal assessment of sperm whale site-specific abundance trends in the northern Gulf of Mexico using passive acoustic data. Journal of Marine Science and Engineering, 9(5), (2021): 454, https://doi.org/10.3390/jmse9050454.Passive acoustic monitoring has been successfully used to study deep-diving marine mammal populations. To assess regional population trends of sperm whales in the northern Gulf of Mexico (GoM), including impacts of the Deepwater Horizon platform oil spill in 2010, the Littoral Acoustic Demonstration Center-Gulf Ecological Monitoring and Modeling (LADC-GEMM) consortium collected broadband acoustic data in the Mississippi Valley/Canyon area between 2007 and 2017 using bottom-anchored moorings. These data allow the inference of short-term and long-term variations in site-specific abundances of sperm whales derived from their acoustic activity. A comparison is made between the abundances of sperm whales at specific sites in different years before and after the oil spill by estimating the regional abundance density. The results show that sperm whales were present in the region throughout the entire monitoring period. A habitat preference shift was observed for sperm whales after the 2010 oil spill with higher activities at sites farther away from the spill site. A comparison of the 2007 and 2015 results shows that the overall regional abundance of sperm whales did not recover to pre-spill levels. The results indicate that long-term spatially distributed acoustic monitoring is critical in characterizing sperm whale population changes and in understanding how environmental stressors impact regional abundances and the habitat use of sperm whales.This research was made possible by the 2015–2019 consortium grant from The Gulf of Mexico Research Initiative

The use of a retrograde fixed-angle intramedullary nail for tibiocalcaneal arthrodesis after severe loss of the talus

Tibiocalcaneal arthrodesis may be the only means of obtaining a painless and stable limb when there is loss of the talus. We present the early results of a prospective study on tibiocalcaneal arthrodesis using a latest-generation retrograde intramedullary nail. In the period 2006–2007, nine patients underwent tibiocalcaneal arthrodesis with retrograde intramedullary nailing. Five of these patients had infection-related loss of the talus. SF-36, AOFAS ankle-hindfoot, and Mazur Ankle Arthrodesis scores were obtained pre-fusion, and at 6 weeks, 6 months and 1 year post-fusion. The patients were also followed up clinically and radiologically. Previous surgical procedures, chronic musculoskeletal problems and other comorbidities, and complications were recorded and analyzed. All patients were available for initial follow-up and were subjectively satisfied with their outcomes. Solid fusion was achieved and fully confirmed in nine cases. One subject died 8 weeks postoperatively of a pulmonary embolism. One patient had recurrent infection. At 1 year, only one patient still needed NSAIDs regularly for pain relief. The AOFAS score improved significantly (P = 0.012) from 32.1 pre-fusion to 71.5 points at 1 year as did the Mazur score, which rose by 31.2 to 72.5 points at 1 year (P = 0.012). The SF-36 score improved significantly in the domains physical functioning, role limitations due to physical problems, bodily pain, vitality, social functioning and mental health, as did the Physical Component Summary Score. Retrograde intramedullary nailing for tibiocalcaneal arthrodesis can produce a good outcome. However, in the presence of infection, patient selection for intramedullary procedures must be carefully considered on a case-by-case basis

Review of the Interactions between Catfishes and Freshwater Mollusks in North America

Catfishes are important in freshwater ecosystems not only as consumers, but also as essential partners in symbiotic relationships with other organisms. Freshwater mollusks are among the many organisms that have interactions with catfishes. For example, ictalurids are hosts for larvae of several native freshwater mussel species. The larvae, which attach briefly to gills or fins of fish to complete their development to the free-living juvenile stage, disperse via upstream and downstream movement of host fish. In turn, freshwater mussels serve as a food source for some catfish species while other catfish species may use spent mussel shells for habitat. Ictalurids also benefit from the conservation status of many freshwater mussel species. Federal and state laws protecting these invertebrates can preserve water quality and habitat and, at times, provide incentives and funding for conservation and restoration of stream and riparian habitats

Analysis of complex drugs by comprehensive two-dimensional gas chromatography and high-resolution mass spectrometry: detailed chemical description of the active pharmaceutical ingredient sodium bituminosulfonate and its process intermediates

The European pharmacopeia provides analytical methods for the chemical characterization of active pharmaceutical ingredients (APIs). However, the complexity of some APIs exceeds the limitations of the currently prevailing physicochemical methods. Sodium bituminosulfonate (SBS) is described by the collection of key parameters of generalizing criteria such as dry matter, sulfur and sodium content, and neutrality, but techniques to unravel the complexity on a molecular level are lacking. We present a study based on online derivatization with tetramethylammonium hydroxide in combination with comprehensive two-dimensional gas chromatography coupled to an electron ionization high-resolution time-of-flight mass spectrometer (GC × GC-HR-ToF–MS) for the chemical description of SBS as well as its process intermediates. The application of GC × GC allowed the comprehensive description of the chemical components in the API and the process intermediates for the first time. Furthermore, it was possible to classify peaks regarding their elemental and structural composition based on accurate mass information, elution behavior, and mass fragmentation pattern. This work demonstrates not only the general applicability, advantages but also limitations of GC × GC for the characterization of APIs for complex drugs. Graphical Abstract: [Figure not available: see fulltext.