Partition-dependent framing effects in lab and field prediction markets

Many psychology experiments show that individually judged probabilities of the same event can vary depending on the partition of the state space (a framing effect called "partition-dependence"). We show that these biases transfer to competitive prediction markets in which multiple informed traders are provided economic incentives to bet on their beliefs about events. We report results of a short controlled lab study, a longer field experiment (betting on the NBA playoffs and the FIFA World Cup), and naturally-occurring trading in macro-economic derivatives. The combined evidence suggests that partition-dependence can exist and persist in lab and field prediction markets

How psychological framing affects economic market prices in the lab and field

A fundamental debate in social sciences concerns how individual judgments and choices, resulting from psychological mechanisms, are manifested in collective economic behavior. Economists emphasize the capacity of markets to aggregate information distributed among traders into rational equilibrium prices. However, psychologists have identified pervasive and systematic biases in individual judgment that they generally assume will affect collective behavior. In particular, recent studies have found that judged likelihoods of possible events vary systematically with the way the entire event space is partitioned, with probabilities of each of N partitioned events biased toward 1/N. Thus, combining events into a common partition lowers perceived probability, and unpacking events into separate partitions increases their perceived probability. We look for evidence of such bias in various prediction markets, in which prices can be interpreted as probabilities of upcoming events. In two highly controlled experimental studies, we find clear evidence of partition dependence in a 2-h laboratory experiment and a field experiment on National Basketball Association (NBA) and Federation Internationale de Football Association (FIFA World Cup) sports events spanning several weeks. We also find evidence consistent with partition dependence in nonexperimental field data from prediction markets for economic derivatives (guessing the values of important macroeconomic statistics) and horse races. Results in any one of the studies might be explained by a specialized alternative theory, but no alternative theories can explain the results of all four studies. We conclude that psychological biases in individual judgment can affect market prices, and understanding those effects requires combining a variety of methods from psychology and economics

Upper Temperature Limit of Environmental Barrier Coatings for Enabling Propulsion Materials Established

Silicon-based ceramics, such as SiC/SiC composites and Si3N4, are the prime candidates for hot section structural components of next-generation gas turbines. A key barrier to such an application is the rapid recession of silicon-based ceramics in combustion environments because of the volatilization of silica scale by water vapor (refs. 1 and 2). Environmental barrier coatings (EBC's) were developed to prevent recession in the High Speed Research--Enabling Propulsion Materials (HSR-EPM) Program (refs. 3 and 4). An investigation under the Ultra-Efficient Engine Technology Program was undertaken at the NASA Glenn Research Center to establish the upper temperature limit of the EPM EBC

The Impact of Non-Equipartition on Cosmological Parameter Estimation from Sunyaev-Zel'dovich Surveys

The collisionless accretion shock at the outer boundary of a galaxy cluster should primarily heat the ions instead of electrons since they carry most of the kinetic energy of the infalling gas. Near the accretion shock, the density of the intracluster medium is very low and the Coulomb collisional timescale is longer than the accretion timescale. Electrons and ions may not achieve equipartition in these regions. Numerical simulations have shown that the Sunyaev-Zel'dovich observables (e.g., the integrated Comptonization parameter Y) for relaxed clusters can be biased by a few percent. The Y-mass relation can be biased if non-equipartition effects are not properly taken into account. Using a set of hydrodynamical simulations, we have calculated three potential systematic biases in the Y-mass relations introduced by non-equipartition effects during the cross-calibration or self-calibration when using the galaxy cluster abundance technique to constraint cosmological parameters. We then use a semi-analytic technique to estimate the non-equipartition effects on the distribution functions of Y (Y functions) determined from the extended Press-Schechter theory. Depending on the calibration method, we find that non-equipartition effects can induce systematic biases on the Y functions, and the values of the cosmological parameters Omega_8, sigma_8, and the dark energy equation of state parameter w can be biased by a few percent. In particular, non-equipartition effects can introduce an apparent evolution in w of a few percent in all of the systematic cases we considered. Techniques are suggested to take into account the non-equipartition effect empirically when using the cluster abundance technique to study precision cosmology. We conclude that systematic uncertainties in the Y-mass relation of even a few percent can introduce a comparable level of biases in cosmological parameter measurements.Comment: 10 pages, 3 figures, accepted for publication in the Astrophysical Journal, abstract abridged slightly. Typos corrected in version

ROSAT HRI X-ray Observations of the Open Globular Cluster NGC 288

A ROSAT HRI X-ray image was obtained of the open globular cluster NGC 288, which is located near the South Galactic Pole. This is the first deep X-ray image of this system. We detect a Low Luminosity Globular Cluster X-ray source (LLGCX) RXJ005245.0-263449 with an X-ray luminosity of (5.5+-1.4)x10^32 ergs/s (0.1-2.0 keV), which is located very close to the cluster center. There is evidence for X-ray variability on a time scale of <~ 1 day. The presence of this LLGCX in such an open cluster suggests that dense stellar systems with high interaction rates are not needed to form LLGCXs. We also searched for diffuse X-ray emission from NGC 288. Upper limits on the X-ray luminosities are L_X^h < 9.5x10^32 ergs/s (0.52-2.02 keV) and L_X^s < 9.3x10^32 ergs/s (0.11-0.41 keV). These imply upper limits to the diffuse X-ray to optical light ratios in NGC 288 which are lower than the values observed for X-ray faint early-type galaxies. This indicates that the soft X-ray emission in these galaxies is due either to a component which is not present in globular clusters (e.g., interstellar gas, or a stellar component which is not found in low metallicity Population II systems), or to a relatively small number of bright Low Mass X-ray Binaries (LMXBs).Comment: The Astrophysical Journal in press. Minor revisions to improve presentation. 6 pages with 3 embedded Postscript figures in emulateapj.st

Decreasing Ventromedial Prefrontal Cortex Activity During Sequential Risk-Taking: An fMRI Investigation of the Balloon Analog Risk Task

Functional imaging studies examining the neural correlates of risk have mainly relied on paradigms involving exposure to simple chance gambles and an economic definition of risk as variance in the probability distribution over possible outcomes. However, there is little evidence that choices made during gambling tasks predict naturalistic risk-taking behaviors such as drug use, extreme sports, or even equity investing. To better understand the neural basis of naturalistic risk-taking, we scanned participants using fMRI while they completed the Balloon Analog Risk Task, an experimental measure that includes an active decision/choice component and that has been found to correlate with a number of naturalistic risk-taking behaviors. In the task, as in many naturalistic settings, escalating risk-taking occurs under uncertainty and might be experienced either as the accumulation of greater potential rewards, or as exposure to increasing possible losses (and decreasing expected value). We found that areas previously linked to risk and risk-taking (bilateral anterior insula, anterior cingulate cortex, and right dorsolateral prefrontal cortex) were activated as participants continued to inflate balloons. Interestingly, we found that ventromedial prefrontal cortex (vmPFC) activity decreased as participants further expanded balloons. In light of previous findings implicating the vmPFC in value calculation, this result suggests that escalating risk-taking in the task might be perceived as exposure to increasing possible losses (and decreasing expected value) rather than the increasing potential total reward relative to the starting point of the trial. A better understanding of how neural activity changes with risk-taking behavior in the task offers insight into the potential neural mechanisms driving naturalistic risk-taking

What is Cyberinfrastructure?

Cyberinfrastructure is a word commonly used but lacking a single, precise definition. One recognizes intuitively the analogy with infrastructure, and the use of cyber to refer to thinking or computing – but what exactly is cyberinfrastructure as opposed to information technology infrastructure? Indiana University has developed one of the more widely cited definitions of cyberinfrastructure: "Cyberinfrastructure consists of computing systems, data storage systems, advanced instruments and data repositories, visualization environments, and people, all linked together by software and high performance networks to improve research productivity and enable breakthroughs not otherwise possible." A second definition, more inclusive of scholarship generally and educational activities, has also been published and is useful in describing cyberinfrastructure: "Cyberinfrastructure consists of systems, data and information management, advanced instruments, visualization environments, and people, all linked together by software and advanced networks to improve scholarly productivity and enable knowledge breakthroughs and discoveries not otherwise possible." In this paper, we describe the origin of the term cyberinfrastructure based on the history of the root word infrastructure, discuss several terms related to cyberinfrastructure, and provide several examples of cyberinfrastructure