Friction Testing of a New Ligature

Objective: To determine if American Orthodontics\u27 (AO) new, experimental ligature demonstrates less friction in vitro when compared to four other ligatures on the market. Methods: Four brackets were mounted on a custom metal fixture allowing an 0.018-in stainless steel wire attached to an opposite fixture with one bracket to be passively centered in the bracket slot. The wire was ligated to the bracket using one of five types of ligatures including the low friction test ligatures (AO), conventional ligatures (AO), Sili–TiesTM, Silicone Infused Ties (GAC), Synergy® Low-Friction Ligatures (RMO), and SuperSlick ligatures (TP Orthodontics). Resistance to sliding was measured over a 7 mm sliding distance using a universal testing machine (Instron) with a 50 Newton load cell and a crosshead speed of 5 mm/min. The initial resistance to sliding (static) was determined by the peak force needed to initiate movement and the kinetic resistance to sliding was taken as the force at 5 mm of wire/bracket sliding. Fifteen unique tests were run for each ligature group in both dry and wet (saliva soaked for 24 hours with one drop prior to testing) conditions. Results: In the dry state, the SuperSlick ligature demonstrated more static friction than all of the other ligatures, while SuperSlick and Sili–Ties demonstrated more kinetic friction than the AO conventional, AO experimental and Synergy ligatures. In the wet condition, SuperSlick and the AO experimental ligature demonstrated the least static friction, followed by the AO conventional and Sili–Ties. The most static friction was observed with the Synergy ligatures. In the wet condition, the SuperSlick, AO experimental and AO conventional exhibited less kinetic friction than the Sili-Ties and Synergy ligatures. Conclusions: AO\u27s experimental ligature exhibits less friction in the wet state than conventional ligatures, Sili–Ties and Synergy and is comparable to the SuperSlick ligature. These preliminary results suggest that the AO experimental ligature and the SuperSlick ligature create less friction, but direct conclusions regarding in vivo performance cannot be made and randomized controlled clinical trials are needed to determine if these ligatures have clinical significance in treatment efficiency

Why do consumers pay bills electronically? an empirical analysis

Why do consumers use electronic bill payment services? what do the differences between nonusers, low users, and high users imply about the potential future market these services? How might public policy evolve in the future? Analyzing a unique consumer survey conducted by the Federal Reserve's Retail Product Office, the author finds important differences between nonusers, low users, and high users of electronic bill payment. The analysis suggests that the industry will need to address fundamental customer needs before a broader portion of consumers will adopt these services.Electronic funds transfers ; Payment systems ; Internet ; Electronic commerce

E-money and e-commerce two alternatives views of future innovations

Electronic commerce ; Payment systems

Design and operational control of an AGV system

In this paper we first deal with the design and operational control of Automated Guided Vehicle (AGV) systems, starting from the literature on these topics. Three main issues emerge: track layout, the number of AGVs required and operational transportation control. An hierarchical queueing network approach to determine the number of AGVs is decribed. Also basic concepts are presented for the transportation control of both a job-shop and a flow-shop. Next we report on the results of a case study, in which track layout and transportation control are the main issues. Finally we suggest some topics for further research

Tanzania Review of Exemptions and Waivers

The work which is presented in this report reflects a need identified by the Ministry of Health to improve the functionality of the exemptions and waivers systems which had been introduced to reduce the financial burden on groups of the population who need access to health care and who either cannot afford to contribute to the costs or who have an illness or disease which threatens the public good and for which no direct charges should be imposed. The exemptions and waivers systems, while potentially very effective in principle, were deemed not to be working well in practice. A significant body of work already exists on the health sector in Tanzania, with plenty of references to the exemptions and waivers systems. The task of the team undertaking this study was not to replicate the work of previous studies but rather to find ways to make some of the recommendations happen. The ‘how to’ element was seen as the most crucial aspect of the work, and the aspect which presented the greatest challenge. The results from all the available documentation were used, and were augmented by field visits to a number of regions and districts in the north and south of the country, where proposals for reinforcement of the waivers and exemptions systems could be tested with practitioners and users of the health sector. The strategy proposed in the document is divided into a long term strategy and an interim strategy. The long terms strategy is to have the whole population of Tanzania covered by one or another insurance scheme, from a selection of current and proposed schemes: the National Health Insurance Fund scheme for civil servants, the Social Security Fund health benefits scheme for formal sector employees, the proposed social insurance scheme for informal sector workers, the CHF or a scheme to cover those who are not eligible or cannot afford to participate in any of the others. The interim strategy identifies ways and means of strengthening the systems to ensure more equitable access to health services for those who are entitled to exemptions and waivers, with recommendations about how those systems can be refined to target those who most need them. Successful examples from the field are used to show the way forward. The interim strategy includes refinement of the exemptions system; expansion and consolidation of the Community Health Fund (CHF); development of TIKA, the urban equivalent of the CHF; the development of an ID card scheme for those who cannot afford to pay or to participate in any of the schemes; and the strengthening of the institutions which provide health care and which plan and monitor the services provided. The ID card scheme, being new to the stable of proposals for strengthening the exemptions and waivers systems, is fully elucidated from the rationale, through the principles behind it, to the identification process for those eligible, the issuing of the card, the roles of each of the institutions at leach level of the administrative structure, the financing of the scheme and the advocacy required to endure that it works the way it is intended by providing for those most in need. Inevitably, the proposals cannot be implemented in a vacuum and where there are risks involved, either general or specific, these have been identified

Optimal linear decision rules for a work force smoothing model with seasonal demand

This paper gives a procevure for the determination of the optimal linear control for a production-inventory system in steady-state with non-linear costs per period and normally distributed seasonal demand. In an example this control policy is compared with other policies

The minimal density of triangles in tripartite graphs

We determine the minimal density of triangles in a tripartite graph with prescribed edge densities. This extends a previous result of Bondy, Shen, Thomass\'e and Thomassen characterizing those edge densities guaranteeing the existence of a triangle in a tripartite graph. To be precise we show that a suitably weighted copy of the graph formed by deleting a certain 9-cycle from $K_{3,3,3}$ has minimal triangle density among all weighted tripartite graphs with prescribed edge densities.Comment: 44 pages including 12 page appendix of C++ cod

A practical solution to a newspaper distribution problem

In this paper the problem of distributing newspapers is treated. After a general introduction on this topic, a mathematical model for a hierarchical distribution system is given explicitly and a heuristic consisting of several solution techniques is described. Furthermore, some results of the application of this heuristic in a study performed for a Dutch regional newspaper are presented and discussed. There is also an indication as to how the approach could be improved

These Woods

pages 25-4

Proceedings of the Thirteenth International Conference on Time-Resolved Vibrational Spectroscopy

The thirteenth meeting in a long-standing series of “Time-Resolved Vibrational Spectroscopy” (TRVS) conferences was held May 19th to 25th at the Kardinal Döpfner Haus in Freising, Germany, organized by the two Munich Universities - Ludwig-Maximilians-Universität and Technische Universität München. This international conference continues the illustrious tradition of the original in 1982, which took place in Lake Placid, NY. The series of meetings was initiated by leading, world-renowned experts in the field of ultrafast laser spectroscopy, and is still guided by its founder, Prof. George Atkinson (University of Arizona and Science and Technology Advisor to the Secretary of State). In its current format, the conference contributes to traditional areas of time resolved vibrational spectroscopies including infrared, Raman and related laser methods. It combines them with the most recent developments to gain new information for research and novel technical applications. The scientific program addressed basic science, applied research and advancing novel commercial applications. The thirteenth conference on Time Resolved Vibrational Spectroscopy promoted science in the areas of physics, chemistry and biology with a strong focus on biochemistry and material science. Vibrational spectra are molecule- and bond-specific. Thus, time-resolved vibrational studies provide detailed structural and kinetic information about primary dynamical processes on the picometer length scale. From this perspective, the goal of achieving a complete understanding of complex chemical and physical processes on the molecular level is well pursued by the recent progress in experimental and theoretical vibrational studies. These proceedings collect research papers presented at the TRVS XIII in Freising, German