Radiation therapy calculations using an on-demand virtual cluster via cloud computing

Computer hardware costs are the limiting factor in producing highly accurate radiation dose calculations on convenient time scales. Because of this, large-scale, full Monte Carlo simulations and other resource intensive algorithms are often considered infeasible for clinical settings. The emerging cloud computing paradigm promises to fundamentally alter the economics of such calculations by providing relatively cheap, on-demand, pay-as-you-go computing resources over the Internet. We believe that cloud computing will usher in a new era, in which very large scale calculations will be routinely performed by clinics and researchers using cloud-based resources. In this research, several proof-of-concept radiation therapy calculations were successfully performed on a cloud-based virtual Monte Carlo cluster. Performance evaluations were made of a distributed processing framework developed specifically for this project. The expected 1/n performance was observed with some caveats. The economics of cloud-based virtual computing clusters versus traditional in-house hardware is also discussed. For most situations, cloud computing can provide a substantial cost savings for distributed calculations.Comment: 12 pages, 4 figure

Strategies for Reducing High Turnover Among Information Technology Professionals

Organizations globally are spending millions of dollars replacing information technology (IT) professionals. IT professionals, who possess technical skills and competencies that interconnect business processes, are costly to replace. There are direct and indirect costs associated when an IT professional leaves, such as advertising fees, headhunting fees, and project delays. Lacking a firm understanding of the reasons why IT professionals leave their positions, many business leaders do not have strategies for reducing turnover rates. Building on Herzberg\u27s motivation-hygiene theory and March and Simon\u27s process model of turnover, this exploratory multiple case study sought to identify the strategies that business leaders view as essential for retaining IT professionals. Semistructured interviews were conducted with 10 IT managers in the Houston, Texas, area; participants were selected using a purposive sampling technique. Thematic analysis revealed eight strategies for addressing turnover: compensation, opportunity and advancement, rewards and recognition, relationship with the supervisor and coworkers, training and development, communications, meaningful work, and flexible work schedule. Findings from this study may contribute to positive social change by providing business leaders with more insight about how they can retain IT professionals. The high turnover among IT professionals affects individuals, families, communities, organizations, and the economy. Implementing strategies to reduce turnover rates can help keep individual employees and their family members together and reduce the unemployment rates

How to lie to God : Kant’s Thomistic turn

For most of his career, Kant accepts Augustine's requirement that lying requires an intention to deceive. However, he eventually converts to Aquinas, following him in rejecting this requirement in favor of Aristotle's teleological conception of lying. This change of view amounts to an improvement, for it makes room for the possibility of lying to an omniscient being—and such lies, we argue, are indeed possible. We accompany these historical and philosophical theses with a biographical thesis taking the form of the following story. Kant believed that in his youth he had lied to God, largely because of his religious training. He adopted policies designed to help him resist the habit of lying to God. However, this program conflicted with his desire to lead a well-rounded life as a public intellectual. This worldly ambition led him to forego the Quaker solution to the problem of lying to God: refuse to swear any oath to God, avoid set prayers and hymns, decline offers of intercession by clergy. Kant's worldly compromise served him well, but as he entered his twilight years, he came to worry that his only surviving argument for theism—the moral argument—might constitute a relapse into the vice of lying to God.Peer reviewe

Comparative Solubility of Protein in Cottonseed Flakes Extracted by Hexane and by Ethanol at Two Different Temperatures

The solubility in water, in 3 percent sodium chloride solution, and in 0.2 N sodium hydroxide solution of cottonseed flakes extracted by ethanol at 172° F. is lower than similar flakes extracted by hexane at 146° F. Data are presented which indicate the lower solubility is mainly the result of the differences in the solvents rather than the temperatures. The difference in solubility in the sodium hydroxide solution is less than in the sodium chloride solution

Improving Pro Forma Analysis through Better Terminal Value Estimates

Basic pro forma analysis often estimates the terminal value input using a simple growing perpetuity assumption. While this assumption is easy to implement, it potentially creates an upward bias in some inputs leading to lower firm or project value outputs. The purpose of this paper is to demonstrate a more accurate way to estimate the terminal value input. Further, by allowing for multiple sales growth rates and by not restricting other input variables to necessarily grow at these same rates, a more accurate, flexible, compact, and thorough analysis is possible