Equilibrium Commodity Prices with Irreversible Investment and Non-Linear Technology

We model equilibrium spot and futures oil prices in a general equilibrium production economy. In our model production of the consumption good requires two inputs: the consumption good and a commodity, e.g., Oil. Oil is produced by wells whose flow rate is costly to adjust. Investment in new Oil wells is costly and irreversible. As a result in equilibrium, investment in Oil wells is infrequent and lumpy. Even though the state of the economy is fully described by a one-factor Markov process, the spot oil price is not Markov (in itself). Rather it is best described as a regime-switching process, the regime being an investment `proximity' indicator. The resulting equilibrium oil price exhibits mean-reversion and heteroscedasticity. Further, the risk premium for exposure to commodity risk is time-varying, positive in the far-from-investment regime but negative in the near-investment regime. Further, our model captures many of the stylized facts of oil futures prices, such as backwardation and the `Samuelson effect.' The futures curve exhibits backwardation as a result of a convenience yield, which arises endogenously. We estimate our model using the Simulated Method of Moments with economic aggregate data and crude oil futures prices. The model successfully captures the first two moments of the futures curves, the average non-durable consumption-output ratio, the average oil consumption-output and the average real interest rate. The estimation results suggest the presence of convex adjustment costs for the investment in new oil wells. We also propose and test a linear approximation of the equilibrium regime-shifting dynamics implied by our model, and test its empirical implication for time-varying risk-premia.

Character Sequence Models for ColorfulWords

We present a neural network architecture to predict a point in color space from the sequence of characters in the color's name. Using large scale color--name pairs obtained from an online color design forum, we evaluate our model on a "color Turing test" and find that, given a name, the colors predicted by our model are preferred by annotators to color names created by humans. Our datasets and demo system are available online at colorlab.us

An Analysis of the Broadband (22-3900 MHz) Radio Spectrum of HB3 (G132.7+1.3): The Detection of Thermal Radio Emission from an Evolved Supernova Remnant?

We present an analysis of the broadband radio spectrum (from 22 to 3900 MHz) of the Galactic supernova remnant (SNR) HB3 (G132.7+1.3). Published observations have revealed that a curvature is present in the radio spectrum of this SNR, indicating that a single synchrotron component appears is insufficient to adequately fit the spectrum. We present here a fit to this spectrum using a combination of a synchrotron component and a thermal bremsstrahlung component. We discuss properties of this latter component and estimate the ambient density implied by the presence of this component to be n \~ 10 cm^-3. We have also analyzed extracted X-ray spectra from archived {\it ASCA} GIS observations of different regions of HB3 to obtain independent estimates of the density of the surrounding interstellar medium (ISM). From this analysis, we have derived electron densities of 0.1-0.4 f^-1/2 cm^-3 for the ISM for the three different regions of the SNR, where f is the volume filling factor. By comparing these density estimates with the estimate derived from the thermal bremsstrahlung component, we argue that the radio thermal bremsstrahlung emission is emitted from a thin shell enclosing HB3. The presence of this thermal bremsstrahlung component in the radio spectrum of HB3 suggests that this SNR is in fact interacting with an adjacent molecular cloud associated with the HII region W3. By extension, we argue that the presence of thermal emission at radio wavelengths may be a useful tool for identifying interactions between SNRs and molecular clouds, and for estimating the ambient density near SNRs using radio continuum data.Comment: 5 pages, 2 figures, accepted for ApJ

Ambiguity and price competition

© 2019, The Author(s). There are few models of price competition in a homogeneous-good market which permit general asymmetries of information amongst the sellers. This work studies a price game with discontinuous payoffs in which both costs and market demand are ex ante uncertain. The sellers evaluate uncertain profits with maximin expected utilities exhibiting ambiguity aversion. The buyers in the market are permitted to split between sellers tieing at the minimum price in arbitrary ways which may be deterministic or random. The role of the primitives in determining equilibrium prices in the market is analyzed in detail

Association of Exposure to Particular Matter and Carotid Intima-Media Thickness: A Systematic Review and Meta-Analysis

Background: Long time exposure to particular matter has been linked to myocardial infarction, stroke and blood pressure, but its association with atherosclerosis is not clear. This meta-analysis was aimed at assessing whether PM2.5 and PM10 have an effect on subclinical atherosclerosis measured by carotid intima-media thickness (CIMT). Methods: Pubmed, Ovid Medline, Embase and NICK between 1948 and 31 March 2015 were searched by combining the keywords about exposure to the outcome related words. The random-effects model was applied in computing the change of CIMT and their corresponding 95% confidence interval (95% CI). The effect of potential confounding factors was assessed by stratified analysis and the impact of traffic proximity was also estimated. Results: Among 56 identified studies, 11 articles satisfied the inclusion criteria. In overall analysis increments of 10 μg/m3 in PM2.5 and PM10 were associated with an increase of CIMT (16.79 μm; 95% CI, 4.95–28.63 μm and 4.13 μm; 95% CI, −5.79–14.04 μm, respectively). Results shown in subgroup analysis had reference value for comparing with those of the overall analysis. The impact of traffic proximity on CIMT was uncertain. Conclusions: Exposure to PM2.5 had a significant association with CIMT and for women the effect may be more obvious

A Longitudinal Analysis of the Indirect Effect of Violence Exposure on Future Orientation Through Perceived Stress and the Buffering Effect of Family Participation

Exposure to violence (ETV) during adolescence has been associated with negative effects in later life, and may negatively affect an individual’s future orientation. Future orientation has important health implications and warrants being studied. Yet, few researchers have examined how ETV affects an individual’s future orientation as a young adult. The purpose of this study was to examine the indirect effect of ETV during adolescence on future orientation as a young adult through perceived stress. We also tested the moderating effect of family participation on the relationship between perceived stress and future orientation. Longitudinal data from a sample of 316 African American participants (42.10% male and 57.90% female, Mage = 14.76 at Wave 1) from low socioeconomic backgrounds recruited from a Midwestern school district were used in the analysis. Multigroup structural equation modeling (SEM) was used to test our hypotheses. Our findings indicated that greater ETV during adolescence is associated with higher levels of perceived stress and, in turn, a more negative outlook on one’s future as a young adult. This indirect effect occurred for individuals with lower family participation, but was not evident for individuals with greater family participation. These findings provide important implications for youth development interventions.HighlightsWe examined how ETV relates to a positive outcome while most researchers focus on negative outcomes.We studied the effects of ETV on future orientation longitudinally.Our findings demonstrate violence exposure to affect future orientation through perceived stress.Our results show that family participation is important for buffering negative effects of stress.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146486/1/ajcp12254.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146486/2/ajcp12254_am.pd

Training Load and Carbohydrate Periodization Practices of Elite Male Australian Football Players: Evidence of Fueling for the Work Required.

The authors aimed to quantify (a) the periodization of physical loading and daily carbohydrate (CHO) intake across an in-season weekly microcycle of Australian Football and (b) the quantity and source of CHO consumed during game play and training. Physical loading (via global positioning system technology) and daily CHO intake (via a combination of 24-hr recall, food diaries, and remote food photographic method) were assessed in 42 professional male players during two weekly microcycles comprising a home and away fixture. The players also reported the source and quantity of CHO consumed during all games (n = 22 games) and on the training session completed 4 days before each game (n = 22 sessions). The total distance was greater (p < .05) on game day (GD; 13 km) versus all training days. The total distance differed between training days, where GD-2 (8 km) was higher than GD-1, GD-3, and GD-4 (3.5, 0, and 7 km, respectively). The daily CHO intake was also different between training days, with reported intakes of 1.8, 1.4, 2.5, and 4.5 g/kg body mass on GD-4, GD-3, GD-2, and GD-1, respectively. The CHO intake was greater (p < .05) during games (59 ± 19 g) compared with training (1 ± 1 g), where in the former, 75% of the CHO consumed was from fluids as opposed to gels. Although the data suggest that Australian Football players practice elements of CHO periodization, the low absolute CHO intakes likely represent considerable underreporting in this population. Even when accounting for potential underreporting, the data also suggest Australian Football players underconsume CHO in relation to the physical demands of training and competition

G55.0+0.3: A Highly Evolved Supernova Remnant

Multi-frequency analysis has revealed the presence of a new supernova remnant, G55.0+0.3, in the Galactic plane. A kinematic distance of 14 kpc has been measured from HI spectral line data. The faint, clumpy half-shell is non-thermal and has a physical radius of 70 pc. Using an evolutionary model, the age of the remnant is estimated to be on the order of one million years, which exceeds conventional limits by a factor of five. The remnant may be associated with the nearby pulsar J1932+2020, which has a spin-down age of 1.1 million years. This work implies that the radiative lifetimes of remnants could be much longer than previously suggested.Comment: 27 pages, 7 figures in 9 files (figures 1 and 2 require 2 files each), Accepted for publication in The Astrophysical Journal (Jan. 20, 1998 volume