We show that the set of projections in an operator system can be detected using only the abstract data of the operator system. Specifically, we show that if is a positive contraction in an operator system  which satisfies certain ordertheoretic conditions, then there exists a complete order embedding of  into ( ) mapping to a projection operator. Moreover, every abstract projection in an operator system  is an honest projection in the C*-envelope of . Using this characterization, we provide an abstract characterization for operator systems spanned by two commuting families of projection-valued measures and discuss applications in quantum information theory.

Undergraduate students learn about mammalian cell culture applications in introductory biology courses. However, laboratory modules are rarely designed to provide hands-on experience with mammalian cells or teach cell culture techniques, such as trypsinization and cell counting. Students are more likely to learn about cell culture using bacteria or yeast, as they are typically easier to grow, culture, and manipulate given the equipment, tools, and environment of most undergraduate biology laboratories. In contrast, the utilization of mammalian cells requires a dedicated biological safety cabinet and rigorous antiseptic techniques. For this reason, we have devised a laboratory module and method herein that familiarizes students with common cell culture procedures, without the use of a sterile hood or large cell culture facility. Students design and perform a time-efficient inquiry-based cell viability experiment using HeLa cells and tools that are readily available in an undergraduate biology laboratory. Students will become familiar with common techniques such as trypsinizing cells, cell counting with a hemocytometer, performing serial dilutions, and determining cell viability using trypan blue dye. Additionally, students will work with graphing software to analyze their data and think critically about the mechanism of death on a cellular level. Two different adaptations of this inquiry-based lab are presented—one for non-biology majors and one for biology majors. Overall, these laboratories aim to expose students to mammalian cell culture and basic techniques and help them to conceptualize their application in scientific research.

Turfgrass quality is often limited by the availability of photosynthetically active radiation (PAR) delivered to the turf surface. The cumulative PAR at a given site during 1 d is termed the daily light integral (DLI) and is an effective measurement for quantifying light requirements for various turfgrass systems. The minimum DLI necessary to maintain acceptable quality on creeping bentgrass (Agrostis stolonifera L.) putting greens has yet to be determined. Shade timing, trinexapac‐ethyl growth regulator, and ultraviolet‐absorbing plant colorant applications may affect the DLI requirement of creeping bentgrass putting greens. The objective of this research was to determine the DLI requirement of a creeping bentgrass putting green by evaluating the effects of shade intensity and timing, as well as the influence of trinexapac‐ethyl and a plant colorant on turfgrass quality and coverage. Intensity treatments of 0, 70, 80, and 90% shade were applied during either morning (sunrise to solar noon) or afternoon (solar noon to sunset) hours from May through October 2016 and 2017 on a ‘Tyee’ creeping bentgrass, sand‐based putting green. Evaluations of visual turf quality and turf coverage were performed every 2 wk. After 2 yr, the DLI requirement to maintain acceptable putting green quality was estimated to be 30 mol m−2 d−1. Although effective in improving turf quality at times during summer months, trinexapac‐ethyl and the plant colorant did not significantly reduce the DLI requirement.

Determining daily light integral (DLI) requirements for turfgrass systems has been an effective method to quantify photosynthetically active radiation (PAR) necessary to maintain quality turfgrass in a research setting. However, there has been little research estimating DLI requirements of popular turfgrass cultivars of zoysiagrass [Zoysia matrella (L.) Merr. and Z. japonica Steud.], hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy], and common bermudagrass [C. dactylon (L.) Pers.] used for teeing grounds and fairways on golf courses. The objective of this research was to (a) determine minimum DLI requirements of two zoysiagrasses, ‘Cavalier’ (Z. japonica) and ‘Meyer’ (Z. matrella), and two bermudagrasses, common bermudagrass (cultivar unknown) and ‘Astro‐DLM’ hybrid bermudagrass; and (b) investigate methodology in rapidly estimating DLI requirements in situ at area golf courses for the same cultivars. Cultivars were evaluated under 22, 40, 60, and 90% shade in a field research setting over two seasons from August through October 2016 and May through October 2017. Turfgrass quality continued to decline over the 2‐yr trial, emphasizing importance of multi‐year evaluations encompassing cumulative effects of shade on turfgrass. Estimated minimum DLI requirements for turf quality of Astro‐DLM hybrid bermudagrass, common bermudagrass, Cavalier zoysiagrass, and Meyer zoysiagrass were 20.4, 25.9, 15.0, and 21.1 mol m−2 d−1, respectively. In situ evaluations at golf course sites accurately estimated DLI requirements for three of four cultivars in comparison to those obtained in field research setting. Established minimum DLI requirements determined for cultivars in this study provide a baseline for site specific turfgrass selection.

Buckhorn plantain populations purportedly resistant to 2,4-D were identified in Pennsylvania following long-term, continual applications of the active ingredient in turfgrass systems. The research objectives of this study were to (1) confirm 2,4-D resistance with dose-response experiments, (2) confirm field resistance of buckhorn plantain to 2,4-D in Pennsylvania, and (3) evaluate alternative herbicides for 2,4-D-resistant buckhorn plantain. Greenhouse dose-response experiments evaluated sensitivity of resistant and susceptible buckhorn plantain biotypes to 2,4-D and halauxifen-methyl, synthetic auxin herbicides from different chemical families. The resistant biotype was ≥ 11.3 times less sensitive to 2,4-D than the susceptible biotype and required a 2,4-D dosage ≥ 6.4 times greater than the standard application rate to reach 50% necrosis. No cross-resistance was observed to halauxifen-methyl as both resistant and susceptible populations were similar in herbicide sensitivity. Field experiments confirmed previous reports of ineffectiveness (≤ 30% reduction) with 2,4-D and other phenoxycarboxylic herbicides in potentially-resistant buckhorn plantain biotypes. Treatments containing halauxifen-methyl reduced resistant biotypes (≥ 70%). This is the first known report of synthetic auxin herbicide resistance for any weed species in Pennsylvania and highlights emerging herbicide resistance challenges in turfgrass systems.