Mars Upper Atmospheric Responses to the 10 September 2017 Solar Flare: A Global, Time‐Dependent Simulation

We report the first global, time‐dependent simulation of the Mars upper atmospheric responses to a realistic solar flare event, an X8.2 eruption on 10 September 2017. The Mars Global Ionosphere‐Thermosphere Model runs with realistically specified flare irradiance, giving results in reasonably good agreement with the Mars Atmosphere and Volatile EvolutioN spacecraft measurements. It is found that the ionized and neutral regimes of the upper atmosphere are significantly disturbed by the flare but react differently. The ionospheric electron density enhancement is concentrated below ∼110‐km altitude due to enhanced solar X‐rays, closely following the time evolution of the flare. The neutral atmospheric perturbation increases with altitude and is important above ∼150‐km altitude, in association with atmospheric upwelling driven by solar extreme ultraviolet heating. It takes ∼2.5 hr past the flare peak to reach the maximum disturbance and then additional ∼10 hr to generally settle down to preflare levels.Key PointsIonospheric perturbation follows the flare in time and is concentrated mostly below 110‐km altitudeNeutral atmospheric perturbation increases with altitude and is important above 150‐km altitudeIt takes the neutral atmosphere 2.5 hr to reach the perturbation peak and 10 more hours to generally recoverPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151860/1/grl59414_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151860/2/grl59414-sup-0001-Text_SI-S01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151860/3/grl59414.pd

Small Platforms, High Return: The Need to Enhance Investment in Small Satellites for Focused Science, Career Development, and Improved Equity

In the next decade, there is an opportunity for very high return on investment of relatively small budgets by elevating the priority of smallsat funding in heliophysics. We've learned in the past decade that these missions perform exceptionally well by traditional metrics, e.g., papers/year/\$M (Spence et al. 2022 -- arXiv:2206.02968). It is also well established that there is a "leaky pipeline" resulting in too little diversity in leadership positions (see the National Academies Report at https://www.nationalacademies.org/our-work/increasing-diversity-in-the-leadership-of-competed-space-missions). Prioritizing smallsat funding would significantly increase the number of opportunities for new leaders to learn -- a crucial patch for the pipeline and an essential phase of career development. At present, however, there are far more proposers than the available funding can support, leading to selection ratios that can be as low as 6% -- in the bottom 0.5th percentile of selection ratios across the history of ROSES. Prioritizing SmallSat funding and substantially increasing that selection ratio are the fundamental recommendations being made by this white paper.Comment: White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 6 pages, 1 figur

Full Agreement and the Provision of Threshold Public Goods

The experimental evidence suggests that groups are inefficient at providing threshold public goods. This inefficiency appears to reflect an inability to coordinate over how to distribute the cost of providing the good. So, why do groups not just split the cost equally? We offer an answer to this question by demonstrating that in a standard threshold public good game there is no collectively rational recommendation. We also demonstrate that if full agreement is required in order to provide the public good then there is a collectively rational recommendation, namely, to split the cost equally. Requiring full agreement may, therefore, increase efficiency in providing threshold public goods. We test this hypothesis experimentally and find support for it

The 'Risk-Adjusted' Price-Concentration Relationship in Banking

Price-concentration studies in banking typically find a significant and negative relationship between consumer deposit rates (i.e., prices) and market concentration. This relationship implies that highly concentrated banking markets are "bad" for depositors. It also provides support for the Structure-Conduct-Performance hypothesis and rejects the Efficient-Structure hypothesis. However, these studies have focused almost exclusively on supply-side control variables and have neglected demand-side variables when estimating the reduced form price-concentration relationship. For example, previous studies have not included in their analysis bank-specific risk variables as measures of cross-sectional derived deposit demand. The authors find that when bank-specific risk variables are included in the analysis the magnitude of the relationship between deposit rates and market concentration decreases by over 50 percent. They offer an explanation for these results based on the correlation between a bank’s risk profile and the structure of the market in which it operates. These results suggest that it may be necessary to reconsider the well-established assumption that higher market concentration necessarily leads to anticompetitive deposit pricing behavior by commercial banks. This finding has direct implications for the antitrust evaluations of bank merger and acquisition proposals by regulatory agencies. And, in a more general sense, these results suggest that any Structure-Conduct-Performance-based study that does not explicitly consider the possibility of very different risk profiles of the firms analyzed may indeed miss a very important set of explanatory variables. And, thus, the results from those studies may be spurious

What Mechanism Design Theorists Had to Say About Laboratory Experimentation in the Mid-1980s

Thanks to the recent studies of the history and philosophy of experimental economics, it is well known that around the early 1980s, experimental economists made a case for the legitimacy of their laboratory work by emphasizing that it was a nice and indispensable complement to mechanism design theorists' mathematical study of institutions. The present paper examines what mechanism design theorists thought of laboratory experimentation, or whether they were willing to form a coalition with experimental economists circa the mid-1980s. By exploring several dimensions of the relationship between mechanism design theory and experimental economics, the present paper shows that a close rapport had been established by the early 1980s between the representative members of the two camps, and also that mechanism design theorists were among the strongest supporters of laboratory experimentation in the economics profession in the mid-1980s

Equipment readiness codes expert system using Joshua for U.S. Army Combat Development

Expert systems have arrived as a popular productivity tool in business, industrial and managerial environments. Such tools should be extensively employed into the U.S. Army environments as well. In this thesis, an example of an expert system and its interface is presented. The expert system created, EQUIPMENT READINESS CODES EXPERT SYSTEM, enables a U.S. Army Combat Development analyst to utilize expert system technology. The advantages achieved are maintaining consistent and accurate Army Combat Development policy, reduction of the tedious, analytical tasks to the power of the machine, and the centralization of expert system maintenance and rule production. Furthermore, this expert system provides the much needed but often scarce expertise to ensure qualitative performance from nonexperts, provides efficiency and consistency of the experts, and even furnishes a training vehicle for others who need to understand the expert's thought process.http://archive.org/details/equipmentreadine1094527725Captain, United States ArmyApproved for public release; distribution is unlimited