A Comparison of Conventional Annual and Alternative Perennial Cropping Systems Under Contemporary and Future Precipitation Scenarios in the US Prairie Pothole Region

There are observed trends that show the climate is changing. Temperatures are rising, and precipitation patterns are shifting. In the central US, it is projected that there will be an increase in the frequency of spring precipitation, and a decrease in the summer. This precipitation shift can lead to an adverse affect on crop yield in farmed potholes, as this area is more susceptible to flooding or ponded conditions. A data gap exists on how crops respond to ponding within these farmed potholes, and if planting an alternative crop that is more resilient to drowning is a viable management change for these areas. We combined a range of future precipitation scenarios with an agroecosystem model to simulate the effects of contemporary (2002-2016) and future precipitation on a conventional corn/soybean (Zea mays L and Glycine max) rotation and an alternative perennial miscanthus (Miscanthus ÃÂÃÂ giganteus Greef et Deu) cropping system. The overall goal of this study was to develop a framework to assess the viability of planting the rhizomatous perennial grass miscanthus in farmed potholes under varying precipitation patterns and ponding conditions and improve the understanding of how traditional and alternative crops within farmed potholes react to a changing climate. In the context of this goal we hypothesized that 1) under the current climate, the control land use will have larger and more frequent losses in yield due to ponding relative to miscanthus, 2) under the future climate, depth and frequency of ponding will increase, but the dynamics of the ponding will be dependent on the way precipitation patterns change, and 3) under any future precipitation scenario, losses due to ponding will be greater in the conventional management of corn/soybean rotation relative to the perennials. On average for the contemporary climate, 40.4% of corn/soybean yields were a total loss, and only 2.2% of the miscanthus yields were a total loss, supporting hypothesis 1. The corn/soybean rotation had more frequent total losses than miscanthus. The depth and frequency of ponding increased under most future precipitation scenarios, partially supporting hypothesis 2. Under two precipitation scenarios, the corn/soybean rotation and miscanthus simulations showed an increase in yield. For the two of the more extreme precipitation scenarios, the miscanthus had greater losses than the corn/soybean rotation. The corn/soybean rotation only experienced greater loss in yield than miscanthus for the most extreme scenario. While the relative losses were greater for some miscanthus scenarios, miscanthus did better in overall total production than corn and soybean. Our results show that compared to a conventional corn/soybean rotation, miscanthus performs better within farmed potholes under future precipitation scenarios. More data is required to further understand the economic viability and environmental benefits of transitioning conventionally farmed potholes to a perennial miscanthus alternative

SWIFT: A Low-Power Network-On-Chip Implementing the Token Flow Control Router Architecture With Swing-Reduced Interconnects

A 64-bit, 8 × 8 mesh network-on-chip (NoC) is presented that uses both new architectural and circuit design techniques to improve on-chip network energy-efficiency, latency, and throughput. First, we propose token flow control, which enables bypassing of flit buffering in routers, thereby reducing buffer size and their power consumption. We also incorporate reduced-swing signaling in on-chip links and crossbars to minimize datapath interconnect energy. The 64-node NoC is experimentally validated with a 2 × 2 test chip in 90 nm, 1.2 V CMOS that incorporates traffic generators to emulate the traffic of the full network. Compared with a fully synthesized baseline 8 × 8 NoC architecture designed to meet the same peak throughput, the fabricated prototype reduces network latency by 20% under uniform random traffic, when both networks are run at their maximum operating frequencies. When operated at the same frequencies, the SWIFT NoC reduces network power by 38% and 25% at saturation and low loads, respectively

Radiative forcing of climate

An update of the scientific discussions presented in Chapter 2 of the Intergovernmental Panel on Climate Change (IPCC) report is presented. The update discusses the atmospheric radiative and chemical species of significance for climate change. There are two major objectives of the present update. The first is an extension of the discussion on the Global Warming Potentials (GWP's), including a reevaluation in view of the updates in the lifetimes of the radiatively active species. The second important objective is to underscore major developments in the radiative forcing of climate due to the observed stratospheric ozone losses occurring between 1979 and 1990

Stronger or longer: Discriminating between Hawaiian and Strombolian eruption styles

The weakest explosive volcanic eruptions globally, Strombolian explosions and Hawaiian fountaining, are also the most common. Yet, despite over a hundred years of observations, no classifications have offered a convincing, quantitative way of demarcating these two styles. New observations show that the two styles are distinct in their eruptive time scale, with the duration of Hawaiian fountaining exceeding Strombolian explosions by ∼300–10,000 s. This reflects the underlying process of whether shallow-exsolved gas remains trapped in the erupting magma or is decoupled from it. We propose here a classification scheme based on the duration of events (brief explosions versus prolonged fountains) with a cutoff at 300 s that separates transient Strombolian explosions from sustained Hawaiian fountains.The authors wish to acknowledge grants from NSF (EAR-0409303, 0810332, 1145159, 1427357) and ARRA (113153 via the Hawaiian Volcano Observatory), which funded this research.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1130/G37423.

Phase Correlations in Cosmic Microwave Background Temperature Maps

We study the statistical properties of spherical harmonic modes of temperature maps of the cosmic microwave background. Unlike other studies, which focus mainly on properties of the amplitudes of these modes, we look instead at their phases. In particular, we present a simple measure of phase correlation that can be diagnostic of departures from the standard assumption that primordial density fluctuations constitute a statistically homogeneous and isotropic Gaussian random field, which should possess phases that are uniformly random on the unit circle. The method we discuss checks for the uniformity of the distribution of phase angles using a non-parametric descriptor based on the use order statistics, which is known as Kuiper's statistic. The particular advantage of the method we present is that, when coupled to the judicious use of Monte Carlo simulations, it can deliver very interesting results from small data samples. In particular, it is useful for studying the properties of spherical harmonics at low l for which there are only small number of independent values of m and which therefore furnish only a small number of phases for analysis. We apply the method to the COBE-DMR and WMAP sky maps, and find departures from uniformity in both. In the case of WMAP, our results probably reflect Galactic contamination or the known variation of signal-to-noise across the sky rather than primordial non-Gaussianity.Comment: 18 pages, 4 figures, accepted for publication in MNRA

On the alleged simplicity of impure proof

Roughly, a proof of a theorem, is “pure” if it draws only on what is “close” or “intrinsic” to that theorem. Mathematicians employ a variety of terms to identify pure proofs, saying that a pure proof is one that avoids what is “extrinsic,” “extraneous,” “distant,” “remote,” “alien,” or “foreign” to the problem or theorem under investigation. In the background of these attributions is the view that there is a distance measure (or a variety of such measures) between mathematical statements and proofs. Mathematicians have paid little attention to specifying such distance measures precisely because in practice certain methods of proof have seemed self- evidently impure by design: think for instance of analytic geometry and analytic number theory. By contrast, mathematicians have paid considerable attention to whether such impurities are a good thing or to be avoided, and some have claimed that they are valuable because generally impure proofs are simpler than pure proofs. This article is an investigation of this claim, formulated more precisely by proof- theoretic means. After assembling evidence from proof theory that may be thought to support this claim, we will argue that on the contrary this evidence does not support the claim

Neutral silicon vacancy centers in undoped diamond via surface control

Neutral silicon vacancy centers (SiV0) in diamond are promising candidates for quantum networks because of their long spin coherence times and stable, narrow optical transitions. However, stabilizing SiV0 requires high purity, boron doped diamond, which is not a readily available material. Here, we demonstrate an alternative approach via chemical control of the diamond surface. We use low-damage chemical processing and annealing in a hydrogen environment to realize reversible and highly stable charge state tuning in undoped diamond. The resulting SiV0 centers display optically detected magnetic resonance and bulk-like optical properties. Controlling the charge state tuning via surface termination offers a route for scalable technologies based on SiV0 centers, as well as charge state engineering of other defects

Childhood Personality, Betrayal Trauma, and Leukocyte Telomere Length in Adulthood: A Lifespan Perspective on Conscientiousness and Betrayal Traumas as Predictors of a Biomarker of Cellular Ageing

Conscientiousness is associated with longevity. As such, identifying the biological pathways linking personality to mortality is important. This study employs longitudinal data spanning >40 years to test prospective associations with leukocyte telomere length (LTL), a potential marker of cellular ageing. Because telomeres shorten over time, and are sensitive to oxidative stress, shorter LTL may reflect cumulative damage associated with negative health behaviours and past stressful events. We investigated childhood conscientiousness as a protective factor, expecting an association with longer LTL in adulthood, possibly reflecting slower LTL shortening. Potential lifespan pathways involving childhood trauma, smoking behaviours, and body mass index (BMI) were explored. Childhood conscientiousness showed a small raw association with LTL (r = .08, p = .04), although this effect did not persist when controlling for age and sex. Despite this lack of a direct effect on LTL, we detected an indirect effect operating jointly through BMI and smoking. Higher rates of childhood betrayal trauma were associated with shorter LTL. Contrary to our hypothesis that conscientiousness would buffer this effect, we found evidence for an interaction with childhood betrayal traumas where the association between childhood betrayal traumas and LTL was larger for those higher on conscientiousness in childhood. Copyright © 2016 European Association of Personality Psycholog

Locked into Copenhagen pledges - Implications of short-term emission targets for the cost and feasibility of long-term climate goals

This paper provides an overview of the AMPERE modeling comparison project with focus on the implications of near-term policies for the costs and attainability of long-term climate objectives. Nine modeling teams participated in the project to explore the consequences of global emissions following the proposed policy stringency of the national pledges from the Copenhagen Accord and Cancún Agreements to 2030. Specific features compared to earlier assessments are the explicit consideration of near-term 2030 emission targets as well as the systematic sensitivity analysis for the availability and potential of mitigation technologies. Our estimates show that a 2030 mitigation effort comparable to the pledges would result in a further “lock-in” of the energy system into fossil fuels and thus impede the required energy transformation to reach low greenhouse-gas stabilization levels (450 ppm CO2e). Major implications include significant increases in mitigation costs, increased risk that low stabilization targets become unattainable, and reduced chances of staying below the proposed temperature change target of 2 °C in case of overshoot. With respect to technologies, we find that following the pledge pathways to 2030 would narrow policy choices, and increases the risks that some currently optional technologies, such as carbon capture and storage (CCS) or the large-scale deployment of bioenergy, will become “a must” by 2030

Correlation of cycles in Lava Lake motion and degassing at Erebus Volcano, Antarctica

Several studies at Erebus volcano have recorded pulsatory behaviour in many of the observable properties of its active lava lake. A strong correlation between the variations in surface speed of the lake and the composition of gas emitted has previously been noted. While previous studies have shown that the SO2 flux and the surface elevation exhibit pulsatory behaviour with a similar period to that of the surface speed and gas composition, suggesting they are linked, a lack of overlap between the di erent measurements has prevented direct comparisons from being made. Using high time-resolution measurements of surface elevation, surface speed, gas composition and SO2 flux we demonstrate for the rst time an unambiguous link between the cyclic behaviour in each of these properties. We also show that the variation in gas composition may be explained by a subtle change in oxygen fugacity. The cycles are found to be in-phase with each other, with a small but consistent lag of 1-3 min between the peaks in surface elevation and surface speed. Explosive events are found to have no observable e ffect on the pulsatory behaviour beyond the ~5 min period required for lake refi ll. The close correspondences between the varying lake surface motion, gas flux and composition, and modelled oxygen fugacity suggest strong links between magma degassing, redox change and the fluid dynamics of the shallow magmatic system.This is the final version of the article. It was originally published by Wiley on behalf of the American Geophysical Union in Geochemistry, Geophysics, Geosystems here: http://onlinelibrary.wiley.com/doi/10.1002/2014GC005399/abstract. It will be embargoed until 19/1/15