A comment on evaluating the cost-effectiveness of armored tactical wheeled vehicles

The article of record as published may be found at https://doi.org/10.1080/10242694.2013.816093This comment discusses the pros and cons of the methodology and data used in our previous study on the cost-effectiveness of armor on Tactical Wheeled Vehicles (TWVs), and responds to recent critiques by Franz Gayl. In our previous article, we evaluated the large-scale Army policies to replace relatively light Type 1 Tactical Wheeled Vehicles (TWVs) with moderately protected Type 2 variants, and later to replace Type 2s with heavily protected Type 3s. We find that the switch from Type 2 to Type 3 TWVs did not appreciably reduce fatalities and were not cost-effective. Mr. Gayl contends that the data and choice of control variables used in our original study negatively bias our findings for Type 3 TWVs. We defend our previous conclusions and argue that Gayl’s suggested approach of focusing on deaths per insurgent attack fails to account for effects of the vehicles on when, where, and how attacks occurred. Our methodology does not suffer from this bias and measures effects on total unit casualties rather those incurred per attack. We explain that our estimates are stable across many specifications and are not sensitive to the choice of controls as Gayl suggests

Filesystem API based on Log Structured Merge (LSM) Trees

This disclosure describes the application of LSM trees as a primitive data structure to provide a file-like Application Programming Interface (API). The LSM tree data structure is used to implement an object store. Namespace features, such as support for directories, can be layered on top of objects to form a hierarchy of object stores, with a root object store connected to an arbitrary number of child object stores that store user directories and files. Since the tree stores deltas on objects, it can contain multiple entries per object ID. However, within a given layer of the tree, there can be at most one entry for a given key within the object. The filesystem achieves performance by writing mutations to a fast in-memory layer, which is flushed at appropriate times to minimize latency caused by disk write operations. Moreover, the use of a journal can help minimize data loss from unflushed write operations in the event of sudden loss of power

Mindset: The 2.5D Platformer

Mindset is a 2.5D platformer video game developed in Unreal Engine. The player must navigate different levels and overcome various challenges on a quest to reach the end of the game. Each level of Mindset is made to represent a different emotion in the protagonist’s life such as contentment, anger, and sadness. Part of the core functionality of the game is this idea that there are two dimensions to every level, a foreground and a background. The challenges in each level incorporate the core mechanic of the game known as “plane shifting” in which the player swaps from foreground to background or vice versa. The challenges in each level revolve around this idea of plane shifting, and it is up to the player to figure out how to solve them

Review of codes of conduct, voluntary guidelines and principles relevant for farm data sharing

Codes of conduct, voluntary guidelines, sets of principles on how to transparently govern farm data are a recent thing. While laws and regulations that govern personal data are becoming more and more common, legislation still does not cover data flows in many industries where different actors in the value chain need to share data and at the same time protect all involved from the risks of data sharing. Data in these value chains is currently governed through private data contracts or licensing agreements, which are normally very complex and on which data producers have very little negotiating power. Codes of conduct have started to emerge to fill the legislative void and to set common standards for data sharing contracts: codes provide principles that the signatories/subscribers/members agree to apply in their contracts

Can the president really affect economic growth? Presidential effort and the political business cycle

The article of record as published may be located at http://dx.doi.org/10.1111/ecin.12111Presidential elections are often seen as referendums on the health of the economy; however, little evidence exists on the president’s ability to influence gross domestic product (GDP). This study examines the effect of the incentive to be reelected and the resulting increase in presidential effort on GDP growth. Growth is found to rise in reelection years for first-term presidents after 1932 and to fall in election years before 1932, when reelection was uncommon, and for second-term presidents generally. This effect is largest for high-quality presidents—who probably have the highest return to effort—and is spread across multiple sectors of the economy

Predicting the Scaling Relations between the Dark Matter Halo Mass and Observables from Generalised Profiles I: Kinematic Tracers

We investigate the relationship between a dark matter halo's mass profile and measures of the velocity dispersion of kinematic tracers within its gravitational potential. By predicting the scaling relation of the halo mass with the aperture velocity dispersion, $M_\mathrm{vir} - \sigma_\mathrm{ap}$, we present the expected form and dependence of this halo mass tracer on physical parameters within our analytic halo model: parameterised by the halo's negative inner logarithmic density slope, $\alpha$, its concentration parameter, $c$, and its velocity anisotropy parameter, $\beta$. For these idealised halos, we obtain a general solution to the Jeans equation, which is projected over the line of sight and averaged within an aperture to form the corresponding aperture velocity dispersion profile. Through dimensional analysis, the $M_\mathrm{vir} - \sigma_\mathrm{ap}$ scaling relation is devised explicitly in terms of analytical bounds for these aperture velocity dispersion profiles: allowing constraints to be placed on this relation for motivated parameter choices. We predict the $M_{200} - \sigma_\mathrm{ap}$ and $M_{500} - \sigma_\mathrm{ap}$ scaling relations, each with an uncertainty of $60.5\%$ and $56.2\%$, respectively. These halo mass estimates are found to be weakly sensitive to the halo's concentration and mass scale, and most sensitive to the size of the aperture radius in which the aperture velocity dispersion is measured, the maximum value for the halo's inner slope, and the minimum and maximum values of the velocity anisotropy. Our results show that a halo's structural and kinematic profiles impose only a minor uncertainty in estimating its mass. Consequently, spectroscopic surveys aimed at constraining the halo mass using kinematic tracers can focus on characterising other, more complex sources of uncertainty and observational systematics.Comment: This paper has been accepted for publication with PAS

Stolen Profits: Civil Shoplifting Demands and the Misuse of Neb. Rev. Stat. § 25–21,194

I. Introduction II. Background ... A. Civil Shoplifting Statutes Generally ... 1. General Authority and Amount Recoverable ... 2. Civil Demand Letters ... 3. Collection of Damages and Penalties Under Civil Shoplifting Statutes ... B. An Overview of Nebraska’s Civil Shoplifting Statute ... 1. The Origins of Nebraska’s Civil Shoplifting Statute ... 2. The Statute as Amended ... 3. Limits on Pre-Litigation Demands Under Neb. Rev. Stat. § 25–21,194 ... a. General Loss-Prevention Costs ... b. Anticipated Litigation Expenses III. Advising the Client ... A. Pay the Demand ... B. Ignore the Demand ... 1. Defending a Claim ... 2. Liability for Attorney’s Fees ... 3. Impact on Credit Rating ... C. Affirmative Legal Challenges ... 1. Federal Challenges ... a. Fair Debt Collections Practices Act … b. Racketeering Influenced and Corrupt Organization Act ... 2. Nebraska Consumer Protection Act ... a. Standing to Sue Under the NCPA ... b. Unfair or Deceptive Business Practice ... c. Trade or Commerce ... d. Affecting Public Interest ... 3. Declaratory Judgment IV. A Call to Action ... A. Legislative Repeal ... B. Legislative Amendment ... C. Education and Enforcement V. Conclusio