A methodology for selective removal of orbital debris

Earth-orbiting objects, large enough to be tracked, were surveyed for possible systematic debris removal. Based upon the statistical collision studies of others, it was determined that objects in orbits approximately 1000 km above the Earth's surface are at greatest collisional risk. Russian C-1B boosters were identified as the most important target of opportunity for debris removal. Currently, more than 100 in tact boosters are orbiting the Earth with apogees between 950 km and 1050 km. Using data provided by Energia USA, specific information on the C-1B booster, in terms of rendezvous and capture strategies, was discussed

Public School Choice and Desegregation in Arkansas

Public school choice is an umbrella term for policies that allow students to enroll in a public school other than their residentially-assigned school. Public school choice, also called openenrollment, is typically divided into two categories: intra-district choice, transfers to schools in the same district, and inter-district choice, transfers to schools in other districts

Problem-solving activities in Biology for Open University students [poster session]

Problem-based learning is a valuable tool for enhancing student learning and for providing remedial help in grasping difficult concepts in Biology. Most teaching at the Open University is by course texts, DVDs and television. Teaching material is written by academics and expert consultants. An important feature of the material is that it includes interactive in-text and self-assessed questions, and also activities which may be home experiments or computer-based. Students are provided with a study calendar that outlines reading and other learning activities for each week of a course. There is provision for face-to-face learning at regional tutorials delivered by associate lecturers. For Biology, Associate lecturers may give a short lecture prior to the problem-based learning exercise, to help students to focus on the relevant concepts. Problem-based learning at tutorials provides opportunities for students to engage with teaching materials and to apply principles to new scenarios not mentioned in course materials e.g. species enzymes, signalling pathways. Problem-based learning also forms part of activities at Residential Schools. Examples of problem based learning activities that have been used successfully in tutorials for Biology at Levels 1–3 are presented. We demonstrate how the activities meet learning outcomes for courses and link to level indicators within programmes of study. Some feedback from students is included

Timed Consistent Network Updates

Network updates such as policy and routing changes occur frequently in Software Defined Networks (SDN). Updates should be performed consistently, preventing temporary disruptions, and should require as little overhead as possible. Scalability is increasingly becoming an essential requirement in SDN. In this paper we propose to use time-triggered network updates to achieve consistent updates. Our proposed solution requires lower overhead than existing update approaches, without compromising the consistency during the update. We demonstrate that accurate time enables far more scalable consistent updates in SDN than previously available. In addition, it provides the SDN programmer with fine-grained control over the tradeoff between consistency and scalability.Comment: This technical report is an extended version of the paper "Timed Consistent Network Updates", which was accepted to the ACM SIGCOMM Symposium on SDN Research (SOSR) '15, Santa Clara, CA, US, June 201

Radiation leukaemogenesis: is virus really necessary?

Generalized lymphosarcomatosis (leukaemia) of non-thymic type occurs in mice bearing 90Sr or 239Pu or 226Ra. Tumours passaged from such mice have been tested for tumour-associated transplantation antigens that could provoke a protective immunity which would be expected if such antigens were determined by virus activated by the irradiation. Sub-threshold doses of living syngeneic tumour, large doses of living allogeneic tumour and large doses of killed syngeneic tumour were without protective effect. This suggests that viruses observed electron micrographically in such tumours are passengers and not causative

Risk-Based Bonus Payments for the Patient-Centered Medical Home

Background The Patient-Centered Medical Home (PCMH) requires fundamental reform of health care financing. We propose a Risk-Based Comprehensive Payment system with risk-adjusted base and bonus payments. Bundled base payments cover the expected cost of primary care services but do not encourage quality. Bonus payments incentivize desired outcomes by rewarding better-than-expected performance in clinical quality, efficiency, and patient-centeredness. Base and bonus payments require credible risk adjustment to discourage practices from cherry-picking easy patients and dumping difficult ones. Methods We estimated models to predict thirteen cost and utilization measures in 17.4 million commercially insured people using diagnoses, age, and sex from Thomson-Reuters MarketScan® 2007 claims data. Using the same data, we imputed assignment of 456,781 people to 436 medium-sized primary care practitioner (PCP) panels (500 – 5000 patients). For each measure, a PCP’s performance is judged by summing the difference between observed (O) and expected (E) outcomes across panel members. For each outcome we calculated: mean; coefficient of variation, or CV = SD/mean; and both individual and grouped R2 as measures of predictive accuracy Results Using risk models to calculate expected outcomes explained 29-49% of the observed patient-level and 85-98% of practice-level variation in performance, with differential variability. Deviation from the mean in total health spending is more variable at the PCP level than other more targeted measures

Pilot Investigation of Correlations Between Supragingival Plaque, Subgingival Plaque and Gingival Crevice Depth

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141157/1/jper0636.pd

Significance of Occlusion in the Etiology and Treatment of Early, Moderate and Advanced Periodontitis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141731/1/jper0511.pd