How Tall is Too Tall?

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Estimating age of rock cairns in southeast Alaska by combining evidence from successional metrics, lichenometry, and carbon dating

We estimated ages of rock cairns in alpine tundra in southeast Alaska by combining information from three general classes of methods, each of them imperfect, but considered together providing better estimates than any of the three alone. We used lichenometry, radiocarbon dating, and five successional metrics: score on a nonmetric multidimensional scaling axis of vegetation composition, cover-weighted average successional class of organisms, overgrowth of contact points between rocks, sum of species cover, and species richness. Lichenometry estimated absolute ages, but with considerable error because we violated key assumptions. Successional metrics provided relative ages, probably with more precision than lichenometry, but did not provide absolute ages. Although the relative age estimates from traditional lichenometry seemed least reliable, collectively they supported the hypothesis of prehistoric origins for the cairns with a range of possible absolute ages of 258–892 years. Similarly, radiocarbon dates for the cairns suggested cairn construction before European settlement, about 450–1500 years B.P. The five successional metrics were in general agreement with each other on relative ages. Combining all methods provided more information than any of the methods alone. We conclude that the cairns were built over a range of times, probably over centuries, most likely 500–1500 years B.P

Maritime Alpine Cairns in Southeast Alaska: A Multidisciplinary Exploratory Study

This report describes the goals, data recovery methods, data analysis, and conclusions of a pilot project “A Multidisciplinary Exploratory Study of Alpine Cairns, Baranof Island, Southeast Alaska,” funded by the National Science Foundation under Project No. 1230132. The project brought together experts in the disciplines of archaeology (University of Nebraska-Lincoln), lichenology (Oregon State University), and Tlingit oral history (Oxford University) to address questions regarding artificial prehistoric, high altitude cairns. Data were collected in 2013 and 2014. Pedestrian archaeological inventory recorded 50 cairns at 5 sites. Archaeological data includes cairn dimensions, GPS positions, still photographic images, and video documentation. Four cairns were selected for excavation/dismantlement based on their morphology and lichen growth. No artifacts occurred within, under, or around the excavated cairns. Radiocarbon (AMS) analysis of collected organic materials and lichenometrics indicate that alpine cairns on Cross Peak are prehistoric and built within the last two millennia. In 2014, a helicopter survey was undertaken over Chichagof Island mountains along the lower reaches of Hoonah Sound. This survey identified 39 cairns at 29 sites demonstrating that alpine cairns occur in abundance on Baranof and Chichagof Islands. Physical, historical, and oral history points to construction of the cairns by ancestors of the Tlingit and, more specifically, by ancestors of Sitka and Kootznoowoo tribes

Quantifying non-star formation associated 8um dust emission in NGC 628

Combining Ha and IRAC images of the nearby spiral galaxy NGC 628, we find that between 30-43% of its 8um dust emission is not related to recent star formation. Contributions from dust heated by young stars are separated by identifying HII regions in the Ha map and using these areas as a mask to determine the 8um dust emission that must be due to heating by older stars. Corrections are made for sub-detection-threshold HII regions, photons escaping from HII regions and for young stars not directly associated to HII regions (i.e. 10-100 Myr old stars). A simple model confirms this amount of 8um emission can be expected given dust and PAH absorption cross-sections, a realistic star-formation history, and the observed optical extinction values. A Fourier power spectrum analysis indicates that the 8um dust emission is more diffuse than the Ha emission (and similar to observed HI), supporting our analysis that much of the 8um-emitting dust is heated by older stars. The 8um dust-to-Ha emission ratio declines with galactocentric radius both within and outside of HII regions, probably due to a radial increase in disk transparency. In the course of this work, we have also found that intrinsic diffuse Ha fractions may be lower than previously thought in galaxies, if the differential extinction between HII regions and diffuse regions is taken into account.Comment: 14 pages, 11 figures, accepted in Ap

Once-weekly semaglutide for patients with type 2 diabetes:a cost-effectiveness analysis in the Netherlands

Objective Choosing therapies for type 2 diabetes that are both effective and cost-effective is vital as healthcare systems worldwide aim to maximize health of the population. The present analysis assessed the cost-effectiveness of once-weekly semaglutide (a novel glucagon-like peptide-1 (GLP-1) receptor agonist) versus insulin glargine U100 (the most commonly used basal insulin) and versus dulaglutide (an alternative once-weekly GLP-1 receptor agonist), from a societal perspective in the Netherlands. Research design and methods The IQVIA CORE Diabetes Model was used to project outcomes for once-weekly semaglutide 0.5 mg and 1 mg versus insulin glargine U100, once-weekly semaglutide 0.5 mg versus dulaglutide 0.75 mg, and once-weekly semaglutide 1 mg versus dulaglutide 1.5 mg. Clinical data were taken from the SUSTAIN 4 and SUSTAIN 7 clinical trials. The analysis captured direct and indirect costs, mortality, and the impact of diabetes-related complications on quality of life. Results Projections of outcomes suggested that once-weekly semaglutide 0.5 mg was associated with improved quality-adjusted life expectancy by 0.19 quality-adjusted life years (QALYs) versus insulin glargine U100 and 0.07 QALYs versus dulaglutide 0.75 mg. Once-weekly semaglutide 1 mg was associated with mean increases in quality-adjusted life expectancy of 0.27 QALYs versus insulin glargine U100 and 0.13 QALYs versus dulaglutide 1.5 mg. Improvements came at an increased cost versus insulin glargine U100, with incremental cost-effectiveness ratios from a societal perspective of _4988 and _495 per QALY gained for once-weekly semaglutide 0.5 mg and 1 mg, respectively, falling below Netherlands-specific willingness-to-pay thresholds. Improvements versus dulaglutide came at a reduced cost from a societal perspective for both doses of once-weekly semaglutide. Conclusions Once-weekly semaglutide is cost-effective versus insulin glargine U100, and dominant versus dulaglutide 0.75 and 1.5 mg for the treatment of type 2 diabetes, and represents a good use of healthcare resources in the Netherlands

The Origins of [CII] Emission in Local Star-forming Galaxies

The [CII] 158um fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [CII] balances the heating, including that due to far-ultraviolet photons, which heat the gas via the photoelectric effect. However, the origin of [CII] emission remains unclear, because C+ can be found in multiple phases of the interstellar medium. Here we measure the fractions of [CII] emission originating in the ionized and neutral gas phases of a sample of nearby galaxies. We use the [NII] 205um fine-structure line to trace the ionized medium, thereby eliminating the strong density dependence that exists in the ratio of [CII]/[NII] 122um. Using the FIR [CII] and [NII] emission detected by the KINGFISH and Beyond the Peak Herschel programs, we show that 60-80% of [CII] emission originates from neutral gas. We find that the fraction of [CII] originating in the neutral medium has a weak dependence on dust temperature and the surface density of star formation, and a stronger dependence on the gas-phase metallicity. In metal-rich environments, the relatively cooler ionized gas makes substantially larger contributions to total [CII] emission than at low abundance, contrary to prior expectations. Approximate calibrations of this metallicity trend are provided.Comment: 8 pages, accepted for publication in Ap

Investigating the effectiveness of many-core network processors for high performance cyber protection systems. Part I, FY2011.

This report documents our first year efforts to address the use of many-core processors for high performance cyber protection. As the demands grow for higher bandwidth (beyond 1 Gbits/sec) on network connections, the need to provide faster and more efficient solution to cyber security grows. Fortunately, in recent years, the development of many-core network processors have seen increased interest. Prior working experiences with many-core processors have led us to investigate its effectiveness for cyber protection tools, with particular emphasis on high performance firewalls. Although advanced algorithms for smarter cyber protection of high-speed network traffic are being developed, these advanced analysis techniques require significantly more computational capabilities than static techniques. Moreover, many locations where cyber protections are deployed have limited power, space and cooling resources. This makes the use of traditionally large computing systems impractical for the front-end systems that process large network streams; hence, the drive for this study which could potentially yield a highly reconfigurable and rapidly scalable solution

Quantum fluctuations can promote or inhibit glass formation

The very nature of glass is somewhat mysterious: while relaxation times in glasses are of sufficient magnitude that large-scale motion on the atomic level is essentially as slow as it is in the crystalline state, the structure of glass appears barely different than that of the liquid that produced it. Quantum mechanical systems ranging from electron liquids to superfluid helium appear to form glasses, but as yet no unifying framework exists connecting classical and quantum regimes of vitrification. Here we develop new insights from theory and simulation into the quantum glass transition that surprisingly reveal distinct regions where quantum fluctuations can either promote or inhibit glass formation.Comment: Accepted for publication in Nature Physics. 22 pages, 3 figures, 1 Tabl