INVESTIGATING THE RELATIONSHIP BETWEEN YIELD RISK AND AGRI-ENVIRONMENTAL INDICATORS

Crop insurance provides risk reduction benefits yet may increase planted acres in risky areas. This paper investigates the relationship between environmental quality and crop insurance induced changes in cropping pattern. Results suggest that yield risk and soil erosion are positively correlated for the majority of acreage in the study area.Environmental Economics and Policy, Risk and Uncertainty,

Study of informative metrics and the volatility mitigating effects of recycling

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 97-101).Metal price volatility is undesirable for firms that use metals as raw materials, because price volatility can translate into volatility of material costs. Volatile material costs and can erode the profitability of the firm, and limit material selection decisions. The undesirability of volatility gives firms an incentive to try to gather advanced information on fluctuations in price, and to manage-or at least control their exposure to-price volatility. It was hypothesized that since price can be a measure of the scarcity of a metal, that other metrics of scarcity risk might correlate with price. A system dynamics simulation of the aluminum supply chain was run to determine how well some commonly used metrics of scarcity correlated with future changes in price, and to explore some conditions that strengthened or weakened those correlations. Additionally, prior work has suggested that increased recycling rates can lower price volatility. The study of the correlation of scarcity risk metrics with price is accompanied by a study on how the technical substitutability of secondary metal for primary, termed secondary substitutability, affects the price volatility. The results show that some scarcity risk metrics modeled (alumina price, primary marginal cost, recycling efficiency, and the static depletion index) weakly correlate with future primary metal price, and hence volatility. Other metrics examined (recycling rate, mining industry Herfindahl Index, the acceleration of the mining rate, and the alumina producer's marginal cost) did not correlate with the future primary price. Correlations were stronger when the demand elasticity was high, the secondary substitutability was high, or the delays in adding primary capacity were low. Regarding managing price volatility, greater secondary substitutability lowers price volatility; likely because it increases the elasticity of substitution of secondary for primary metal-this result is explored mathematically. The model results show that some scarcity risk metrics do weakly correlate with future primary price, but the strength of the correlation depends on certain market conditions. Moreover, firms may have some ability to manage price volatility by increasing the limit for how much secondary metal they can use in their product.by Nathan Richard Fleming.S.M.in Technology and PolicyS.M

Waterfowl Population Status, 2010

In the traditional survey area, which includes strata 1‒18, 20‒50, and 75‒77, the total duck population estimate was 40.9 ± 0.7 [SE] million birds. This estimate was similar to last year\u27s estimate of 42.0 ± 0.7 million birds and was 21% above the long-term average (1955‒2009). Estimated mallard (Anas platyrhynchos) abundance was 8.4 ± 0.3 million birds, which was similar to the 2009 estimate of 8.5 ± 0.2 million birds and 12% above the long-term average. Estimated abundance of gadwall (A. strepera; 3.0 ± 0.2 million) was similar to the 2009 estimate and 67% above the long-term average. Estimated abundance of American wigeon (A. americana; 2.4 ± 0.1 million) was similar to 2009 and the long-term average. The estimated abundance of green-winged teal (A. crecca) was 3.5 ± 0.2 million, which was similar to the 2009 estimate and 78% above their longterm average of 1.9 ± 0.02 million. The estimate of blue-winged teal abundance (A. discors) was 6.3 ± 0.4 million, which was 14% below the 2009 estimate and 36% above their long-term average of 4.7 ± 0.04 million. The estimate for northern pintails (A. acuta; 3.5 ± 0.2 million) was similar to the 2009 estimate, and 13% below the long-term average of 4.0 ± 0.04 million. Estimates of northern shovelers (A. clypeata; 4.1 ± 0.2 million) and redheads (Aythya americana; 1.1 ± 0.1 million) were similar to their 2009 estimates and were 76% and 63% above their long-term averages of 2.3 ± 0.02 million and 0.7 ± 0.01 million, respectively. The canvasback estimate (A. valisineria; 0.6 ± 0.05 million) was similar to the 2009 estimate and to the long-term average. The scaup estimate (A. affinis and A. marila combined; 4.2 ± 0.2 million) was similar to that of 2009 and 16% below the long-term average of 5.1 ± 0.05 million. Habitat conditions during the 2010 Waterfowl Breeding Population and Habitat Survey were characterized by average to below-average moisture, a mild winter, and early spring across the traditional and eastern survey areas. The total pond estimate (Prairie Canada and U.S. combined) was 6.7 ± 0.2 million. This was similar to the 2009 estimate and 34% above the long-term average (1974‒2009) of 5.0 ± 0.03 million ponds. The 2010 estimate of ponds in Prairie Canada was 3.7 ± 0.2 million. This was similar to last year\u27s estimate (3.6 ± 0.1 million) and to the long-term average (1961‒2009; 3.4 ± 0.03 million). The 2010 pond estimate for the north central U.S. was 2.9 ± 0.1 million, which was similar to last year\u27s estimate (2.9 ± 0.1 million) and 87% above the long-term average (1974‒2009; 1.6 ± 0.02 million). The projected mallard fall-flight index is 10.3 ± 0.9 million birds. The eastern survey area was restratifed in 2005 and is now composed of strata 51‒72. Estimates of mallards, scaup, scoters (black [Melanitta nigra], white-winged [M. fusca], and surf [M. perspicillata]), green-winged teal, American wigeon, bufflehead (Bucephala albeola), ring-necked duck (Aythya collaris), and goldeneyes (common [B. clangula] and Barrow\u27s [B. islandica]) were all similar to their 2009 estimates and long-term averages. The merganser (red-breasted [Mergus serrator], common [M. merganser], and hooded [Lophodytes cucullatus]) estimate was 386.4 thousand, which was 15% below the 2009 estimate, and 14% below the long-term average of 450.8 thousand. The American black duck (Anas rubripes) estimate was similar to the 2009 estimate and 7% below the long-term average of 478.9 thousand

Sharing and visualizing environmental data using Virtual Globes

Virtual globe technology holds many exciting possibilities for environmental science. These easy-to-use, intuitive systems provide means for simultaneously visualizing four-dimensional environmental data from many different sources, enabling the generation of new hypotheses and driving greater understanding of the Earth system. Through the use of simple markup languages, scientists can publish and consume data in interoperable formats without the need for technical assistance. In this paper we give, with examples from our own work, a number of scientific uses for virtual globes, demonstrating their particular advantages. We explain how we have used Web Services to connect virtual globes with diverse data sources and enable more sophisticated usage such as data analysis and collaborative visualization. We also discuss the current limitations of the technology, with particular regard to the visualization of subsurface data and vertical sections

Hypersparse Traffic Matrix Construction using GraphBLAS on a DPU

Low-power small form factor data processing units (DPUs) enable offloading and acceleration of a broad range of networking and security services. DPUs have accelerated the transition to programmable networking by enabling the replacement of FPGAs/ASICs in a wide range of network oriented devices. The GraphBLAS sparse matrix graph open standard math library is well-suited for constructing anonymized hypersparse traffic matrices of network traffic which can enable a wide range of network analytics. This paper measures the performance of the GraphBLAS on an ARM based NVIDIA DPU (BlueField 2) and, to the best of our knowledge, represents the first reported GraphBLAS results on a DPU and/or ARM based system. Anonymized hypersparse traffic matrices were constructed at a rate of over 18 million packets per second

Outer membrane β-barrel protein folding is physically controlled by periplasmic lipid head groups and BamA.

Outer membrane β-barrel proteins (OMPs) are crucial for numerous cellular processes in prokaryotes and eukaryotes. Despite extensive studies on OMP biogenesis, it is unclear why OMPs require assembly machineries to fold into their native outer membranes, as they are capable of folding quickly and efficiently through an intrinsic folding pathway in vitro. By investigating the folding of several bacterial OMPs using membranes with naturally occurring Escherichia coli lipids, we show that phosphoethanolamine and phosphoglycerol head groups impose a kinetic barrier to OMP folding. The kinetic retardation of OMP folding places a strong negative pressure against spontaneous incorporation of OMPs into inner bacterial membranes, which would dissipate the proton motive force and undoubtedly kill bacteria. We further show that prefolded β-barrel assembly machinery subunit A (BamA), the evolutionarily conserved, central subunit of the BAM complex, accelerates OMP folding by lowering the kinetic barrier imposed by phosphoethanolamine head groups. Our results suggest that OMP assembly machineries are required in vivo to enable physical control over the spontaneously occurring OMP folding reaction in the periplasm. Mechanistic studies further allowed us to derive a model for BamA function, which explains how OMP assembly can be conserved between prokaryotes and eukaryotes.This is the author accepted manuscript. The final version is available from the National Academy of Sciences via http://dx.doi.org/10.1073/pnas.132247311

Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey

Studies of Galactic chemical and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (Teff, [Fe/H] and log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. While most surveys use spectral synthesis, in this work we employ an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R~12,000). We have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices and, through the comparison of those with values calculated with pre-determined calibrations, derive the atmospheric parameters of the stars. The calibrations were built using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters from high-resolution spectroscopic analysis. Our approach was able to recover the parameters within 80 K for Teff, 0.05 dex for [Fe/H] and 0.15 dex for log g, values that are lower or equal to the typical external uncertainties found between different high-resolution analyzes. An additional test was performed with a subsample of 138 stars from the ELODIE stellar library and the literature atmospheric parameters were recovered within 125 K for Teff, 0.10 dex for [Fe/H] and 0.29 dex for log g. These results show that the spectral indices are a competitive tool to characterize stars with the intermediate resolution spectra.Comment: Accepted for publication in AJ. Abstract edited to comply with arXiv standards regarding the number of character

The Efficacy of Simulation as a Pedagogy in Facilitating Pre-Service Teachers’ Learning About Emotional Self-Regulation and its Relevance to the Teaching Profession

This study was undertaken in response to the imperative of teacher education courses incorporating National Professional Standards for Teachers, in particular Standard 7, which deals with the professional engagement of teachers (AITSL, 2011). It aimed to evaluate the efficacy of simulation and active recall as a learner-centred pedagogy in facilitating pre-service teachers’ learning about their capacity to self-regulate emotionally and its relevance to the profession. A simulated ‘critical incident’ was used in a lecture to guide students (n=106) to analyse and understand their emotional responses to an altercation between the lecturer and a colleague. The evaluation involved both quantitative and qualitative data collection. The study generated six useful insights associated with the efficacy of simulation pedagogy and revealed convincingly that this pedagogy can engage students actively in learning about the importance of emotional self-regulation in relation to their professional role as a teacher