Search for: All records

The evolution of antibiotic resistance in bacteria is a significant public health risk influenced by several factors. Switched systems can abstract the evolutionary aspects driven by antibiotic use in a given population. However, mathematical models are not perfect, and uncertain dynamics remain. Based on a set theory approach, our main result is the development of an algorithm to demonstrate the stabilizability of a robust invariant set for the uncertain switched system. The algorithm also provides a characterization of invariant regions for switched systems under perturbations. Our findings provide insights into how to incorporate uncertainties in switched systems. This paves the way for selecting antibiotics to tackle drug-resistant infections. 

This flux-tower observational campaign occurred in Utqiagvik, AK. A 12-m tower was installed in February 2022 to collect turbulence data at a total of five heights (0.5 m, 1.5 m, 2.5 m, 3.5 m, and 7.5 m). At each height, a Campbell Scientific CSAT3B sonic anemometer was operated to measure three velocity components and virtual temperature at 50 Hz, and an R. M. Young temperature and relative sensor was operated to measure air temperature and relative humidity at 1 Hz. The effective data collection was during March--April 2022, until the tower was taken down in April 2022. This was the first dataset of Arctic turbulence collected at 50 Hz, a frequency substantially higher than previous measurements at 10 Hz and 20 Hz. Given the strongly stable conditions in the Arctic, increasing the sampling frequency to 50 Hz was critical to resolve near-surface turbulence within or at least close to the inertial subrange. 

STEM technician education programs face a world in which cutting-edge technologies are transforming existing industries and creating new ones at an unprecedented pace. In light of this, the NSF ATE project Preparing Technicians for the Future of Work conducted industry site interviews and regional convenings of academic partners and industry leaders representing a wide range of technical fields to learn how technology impacts technician job tasks and roles. Through these activities, the project identified three skill areas common across multiple technologies and deemed essential for future STEM technicians: data knowledge/analysis, advanced digital literacy, and business knowledge/processes. These “cross-disciplinary STEM core” skill sets and recommendations for integrating them into technical programs are described in A Framework for a Cross-Disciplinary STEM Core. To facilitate adoption of the Framework at a systemic level, the project is sharing an adoption toolkit with concrete steps a college can take, tools it can use with employers to prioritize STEM Core skill sets and faculty activities for identifying where prioritized skills are taught within existing program curriculum and instructional gaps where new cross-disciplinary skill sets could be easily integrated. 

Two regional universities have completed the first round of a three-year collaborative NSF Research Experience for Teachers grant focused on human-centered design and appropriate technology for developing countries. In this transformative research experience, teachers travel to global community partner sites to engage in learning projects aimed to enhance their understanding of engineering and intercultural awareness. Upon return from their immersion experience, the teachers complete an intensive, two-week curriculum development workshop. The teachers then pilot the resulting lesson(s) in their classroom, make revisions as necessary, and share their finalized curriculum with other STEM educators via the TeachEngineering website. Throughout the experience, teachers benefit professionally through integrated development activities and cultivate greater self-awareness and understanding of culture. First, this paper will summarize the project to date. Then, we present observations from participants’ reflections, semi-structured interview, and pre/post intercultural assessments. Next, we highlight the collaborative outreach and capacity-building efforts which resulted in a new community partner and immersion site. Finally, we discuss the unique opportunities and challenges associated with navigating international travel and immersion experiences during the COVID-19 pandemic. 

The circumgalactic medium (CGM) is a critical repository for metals around galaxies, and serves as the meeting ground for galactic outflows and infalling material from the intergalactic medium. We study the net flow of metals through the CGM in the IllustrisTNG galaxy formation simulations, with a particular focus on the geometry and radial distribution of metal flows. Special care is taken to account for “fuzz” particles, which are often missed by traditional methods of selecting CGM particles in the Illustris simulations, but dominate the net outflow of gas around massive galaxies near the virial radius. 

Abstract Superconducting on-chip filter banks provide a scalable, space saving solution to create imaging spectrometers at millimetre and submillimetre wavelengths. We present an easy to realise, lithographed superconducting filter design with a high tolerance to fabrication error. Using a capacitively coupled $$\lambda /2$$ λ / 2 microstrip resonator to define a narrow ( $$\lambda /\Delta \lambda = 300$$ λ / Δ λ = 300 ) spectral pass band, the filtered output of a given spectrometer channel directly connects to a lumped-element kinetic inductance detector. We show the tolerance analysis of our design, demonstrating $$<11\%$$ < 11 % change in filter quality factor to any one realistic fabrication error and a full filter-bank efficiency forecast to be 50% after accounting for fabrication errors and dielectric loss tangent.