Do it Right or Not at All: A Longitudinal Evaluation of a Conflict Managment System Implementation

We analyzed an eight-year multi-source longitudinal data set that followed a healthcare system in the Eastern United States as it implemented a major conflict management initiative to encourage line managers to consistently perform Personal Management Interviews (or PMIs) with their employees. PMIs are interviews held between two individuals, designed to prevent or quickly resolve interpersonal problems before they escalate to formal grievances. This initiative provided us a unique opportunity to empirically test key predictions of Integrated Conflict Management System (or ICMS) theory. Analyzing survey and personnel file data from 5,449 individuals from 2003 to 2010, we found that employees whose managers provided high-quality interviews perceived significantly higher participative work climates and had lower turnover rates. However, retention was worse when managers provided poor-quality interviews than when they conducted no interviews at all. Together these findings highlight the critical role that line mangers play in the success of conflict management systems

Morphometric Analysis of Dinosaur Tracks from Southwest Arkansas

Dinosaur trackways were discovered in Cretaceous De Queen Limestone strata in Howard County, Arkansas, in June 2011. Multiple trackways with variably sized tridactyl tracks were exposed in a commercial quarry, suggesting multiple theropod species or adult and juvenile tracks of a single species. Results of morphometric analyses of 32 plaster casts from selected trackways are reported in an effort to identify the specific track-making dinosaurs and differentiate large and small tracks. Track measurements included length and width of each track, the lengths and widths of each digit impression, and the angular spread (divarication) between digit impressions. Twenty-nine plaster casts were of tridactyl theropod tracks whereas three casts were of poorly preserved tracks of a presumed but unknown tetradactyl (and possibly tetrapod) organism. Plaster casts of tridactyl theropod tracks ranged from 0.36 to 0.61 m long and 0.22 to 0.54 m wide. The longest digit impression on each track was the second, or middle, digit (range = 0.15 – 0.35 m long) with total digit divarication ranging from 31 - 57 degrees. The Arkansas track measurements were compared to tracks (Eubrontes glenrosensis Shuler 1935) preserved in the correlative Glen Rose Formation, Texas and attributed to the large Early Cretaceous carnosaur, Acrocanthosaurus atokensis. The E. glenrosensis track measurements from Texas plotted within the Arkansas data range, suggesting affinity of the Arkansas tracks to E. glenrosensis. Relatively poor preservation of tetradactyl tracks precluded morphometric analysis, but visual comparison to known Cretaceous crocodilian tracks is suggestive of affinity to such organisms

Long-term tidal evolution of short-period planets with companions

Of the fourteen transiting extrasolar planetary systems for which radii have been measured, at least three appear to be considerably larger than theoretical estimates suggest. It has been proposed by Bodenheimer, Lin & Mardling that undetected companions acting to excite the orbital eccentricity are responsible for these oversized planets, as they find new equilibrium radii in response to being tidally heated. In the case of HD 209458, this hypothesis has been rejected by some authors because there is no sign of such a companion at the 5 m/s level, and because it is difficult to say conclusively that the eccentricity is non-zero. Transit timing analysis [...]. Whether or not a companion is responsible for the large radius of HD 209458b, almost certainly some short-period systems have companions which force their eccentricities to nonzero values. This paper is dedicated to quantifying this effect. The eccentricity of a short-period planet will only be excited as long as its (non-resonant) companion's eccentricity is non-zero. Here we show that the latter decays on a timescale which depends on the structure of the interior planet, a timescale which is often shorter than the lifetime of the system. This includes Earth-mass planets in the habitable zones of some stars. We determine which configurations are capable of sustaining significant eccentricity for at least the age of the system, and show that these include systems with companion masses as low as a fraction of an Earth mass. The orbital parameters of such companions are consistent with recent calculations which show that the migration process can induce the formation of low mass planets external to the orbits of hot Jupiters. Systems with inflated planets are therefore good targets in the search for terrestrial planets.Comment: 25 pages, 19 figures. Accepted for publication in MNRA

On the Evolution and Survival of Protoplanets Embedded in a Protoplanetary Disk

We model the evolution of a Jupiter-mass protoplanet formed by the disk instability mechanism at various radial distances accounting for the presence of the disk. Using three different disk models, it is found that a newly-formed Jupiter-mass protoplanet at radial distance of $\lesssim$ 5-10 AU cannot undergo a dynamical collapse and evolve further to become a gravitational bound planet. We therefore conclude that {\it giant planets, if formed by the gravitational instability mechanism, must form and remain at large radial distances during the first $\sim$ 10$^5-10^6$ years of their evolution}. The minimum radial distances in which protoplanets of 1 Saturn-mass, 3 and 5 Jupiter-mass protoplanets can evolve using a disk model with $\dot{M}=10^{-6} M_{Sun}/yr$ and $\alpha=10^{-2}$ are found to be 12, 9, and 7 AU, respectively. The effect of gas accretion on the planetary evolution of a Jupiter-mass protoplanet is also investigated. It is shown that gas accretion can shorten the pre-collapse timescale substantially. Our study suggests that the timescale of the pre-collapse stage does not only depend on the planetary mass, but is greatly affected by the presence of the disk and efficient gas accretion.Comment: 26 pages, 2 tables, 10 figures. Accepted for publication in Ap

Control, Risk and Information Security Precautions

The introduction of the Internet to the business world has changed many ways of doing business. Unfortunately, the Internet has also become an arena where individuals are constantly at risk for computer viruses, spyware/adware infection, and malicious attacks designed to misuse or appropriate corporate assets. The wide-spread publicity of both cyber-attacks and ways to combat these problems, public and corporate education efforts, and prevention efforts (including corporate spending on new protections and enforcement of existing policies), suggest that it is logical for users to put precautionary practices in place. Unfortunately, they often don’t. Many individuals within organizations underestimate their vulnerability and do not follow prescribed security policies and procedures implemented within their organizations. Extant security literature heavily emphasizes automatic or programmed security measures, but does not focus strongly on the behaviors of individuals in the security setting. This paper examines two research questions: What are the effects of organizational policies and procedures on security precautions taken by individuals? What is the role that individual risk perceptions play in individual cyberprecautions choices? These questions will be addressed by theory taken from the formal control and fear of crime literatures. This theory posits that formal controls and individuals’ experiences have a strong effect on both individual perceptions of mandatory rules and individual risk perceptions. These perceptions, in turn, lead to precaution-taking behaviors. The resulting model will be tested with a field survey

On The Effect of Giant Planets on the Scattering of Parent Bodies of Iron Meteorite from the Terrestrial Planet Region into the Asteroid Belt: A Concept Study

In their model for the origin of the parent bodies of iron meteorites, Bottke et al proposed differentiated planetesimals that were formed in the region of 1-2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these objects and their fragments were scattered into the asteroid belt as a result of interactions with planetary embryos. Although viable, this model does not include the effect of a giant planet that might have existed or been growing in the outer regions. We present the results of a concept study where we have examined the effect of a planetary body in the orbit of Jupiter on the early scattering of planetesimals from terrestrial region into the asteroid belt. We integrated the orbits of a large battery of planetesimals in a disk of planetary embryos, and studied their evolutions for different values of the mass of the planet. Results indicate that when the mass of the planet is smaller than 10 Earth-masses, its effects on the interactions among planetesimals and planetary embryos is negligible. However, when the planet mass is between 10 and 50 Earth-masses, simulations point to a transitional regime with ~50 Earth-mass being the value for which the perturbing effect of the planet can no longer be ignored. Simulations also show that further increase of the mass of the planet strongly reduces the efficiency of the scattering of planetesimals from the terrestrial planet region into the asteroid belt. We present the results of our simulations and discuss their possible implications for the time of giant planet formation.Comment: 20 pages, 7 figures, accepted for publication in Ap

Parts and materials application review for space systems

Parts and materials application review for project management of space systems engineerin