Spin-String Interaction in QCD Strings

I consider the question of the interaction between a QCD string and the spin of a quark or an antiquark on whose worldline the string terminates. The problem is analysed from the point of view of a string representation for the expectation value of a Wilson loop for a spin-half particle. A string representation of the super Wilson loop is obtained starting from an effective string representation of a Wilson Loop. The action obtained in this manner is invariant under a worldline supersymmetry and has a boundary term which contains the spin-string interaction. For rectangular loops the spin-string interaction vanishes and there is no spin-spin term in the resulting heavy quark potential. On the other hand if an allowance is made for the finite intrinsic thickness of the flux-tube, by assuming that the spin-string interaction takes place not just at the boundary of the string world-sheet but extends to a distance of the order of the intrinsic thickness of the flux tube, then we do obtain a spin-spin interaction which falls as the fifth power of the distance. Such a term was previously suggested by Kogut and Parisi in the context of a flux-tube model of confinement.Comment: 19 pages, 1 figure; Published version with added discussion and references in section

The Perspectives of Reverse Transfer Srudents at Two-Year Technical Colleges

Reverse transfer students begin at a four-year college then transfer to a two-year college. Two-year technical colleges provide career-based education to students for employment in specific trades, The perspectives of seven successful reverse transfer students attending a fwo-year technical college were obtained through in-depth interviews to understand the nature of reverse transferring to a technical college, the reasons for their success, and the lessons that can be learned for sfudents and colleges. From the data five themes emerged: the participants were all successful high school students; they did not adequately select their first college; they held common beliefs about the role of higher education; their ability to connect with other students, staff, and the school impacted their success. Furthermore, findings indicated that they benefitted from the transfer itself: maturing over time; reflecting on their own preferences; and gaining experience outside of the classroom

Benchmarking the Urology Practice

The medical practice today is relentlessly challenged by medical progress, by rising costs, and by the mounting pressures of the managed care environment. It should be the approach of every medical practice manager and practitioner to seek out and measure up to the best standards so as to optimize patient care and business outcomes. This requires the resolute pursuit of good models, brought about by the fostering of key collaborative relationships that are both practical and strategic. Integral to this process is benchmarking: the way by which information is obtained from both internal and external sources to determine and set the standards for performance. Benchmarking is an invaluable strategic tool

Effects of orbital exposure on Halar during the LDEF mission

Thermomechanical Analysis (TMA), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA) were performed on samples of Halar exposed on the LDEF Mission for 6 years in orbit and unexposed Halar control samples. Sections 10-100 microns thick were removed from the exposed surface down to a depth of 1,000 microns through the 3 mm thick samples. The TMA and DSC results, which arise from the entire slice and not just its surface, showed no differences between the LDEF and the control samples. TMA scans were run from ambient to 300 C; results were compared by a tabulation of the glass transition temperatures. DSC scans were run from ambient to 700 C; the enthalpy of melting was compared for the samples as a function of section depth with the sample. The TGA results, which arise from the surface of the sample initially, showed a sharp increase in the topmost 50 micron section (the exposed, discolored side) in the weight loss of 170 C in oxygen. This weight loss dropped to bulk values in the range of depth of 50-200 microns. The control sample showed only a slight increase in weight loss as the top surface was approached. The LDEF Halar sample appears to be mechanically undamaged, with a surface layer which oxidizes faster as a result of orbital exposure