On the initial value problem of a periodic box-ball system

We show that the initial value problem of a periodic box-ball system can be solved in an elementary way using simple combinatorial methods.Comment: 9 pages, 2 figure

Sequential sampling strategy for the modeling of parameterized microwave and RF components

Accurate modeling of parameterized microwave and RF components often requires a large number of full-wave electromagnetic simulations. In order to reduce the overall simulation cost, a sequential sampling algorithm is proposed that selects a sparse set of data samples which characterize the overall response of the system. The resulting data samples can be fed into existing modeling techniques. The effectiveness of the approach is illustrated by a parameterized H-shaped microwave antenna

Dynamic phase transition in the conversion of B-DNA to Z-DNA

The long time dynamics of the conformational transition from B-DNA to Z-DNA is shown to undergo a dynamic phase transition. We obtained the dynamic phase diagram for the stability of the front separating B and Z. The instability in this front results in two split fronts moving with different velocities. Hence, depending on the system parameters a denatured state may develop dynamically eventhough it is thermodynamically forbidden. This resolves the current controversies on the transition mechanism of the B-DNA to Z-DNA.Comment: 5 pages, 4 figures. New version with correction of typos, new references, minor modifications in Fig 2, 3. To appear in EP

Electing a parliament

We present a model where a society elects a parliament by voting for candidates belonging to two parties. The electoral rule determines the seats distribution between the two parties. We analyze two electoral rules, multidistrict majority and single-district proportional. In this framework, the policy outcome is simply a function of the number of seats parties take in the election. We prove that in both systems there is a unique pure strategy perfect equilibrium outcome. Finally, we compare the outcomes in the two systems

International Scope of Emergency Ultrasound: Barriers in Applying Ultrasound to Guide Central Line Placement by Providers in Nairobi, Kenya

Background: While ultrasound (US) use for internal jugular central venous catheter (CVC) placement is standard of care in North America, most developing countries have not adopted this practice. Previous surveys of North American physicians have identified lack of training and equipment availability as the most important barriers to the use of US. Objective: We sought to identify perceived barriers to the use of US to guide CVC insertion in a resource-constrained environment. Methods: Prior to an US-guided CVC placement training course conducted at the Aga Khan University Hospital in Nairobi, Kenya, physicians were asked to complete a survey to determine previous experience and perceived barriers. Survey responses were analyzed using summary statistics and the Rank-Sum test based on different specialty, gender, and previous US experience. Results: There were 23 physicians who completed the course and the survey. 52% (95% CI: 0.30–0.73) had put in \u3e20 CVCs. 21.7% (95% CI: 0.08–0.44) of participants had previous US training, but none in the use of US for CVC insertion. The respondents expressed agreement with statements describing the ease of the use and improved success rate with US guidance. There was less agreement to statements describing the relative convenience and cost effectiveness of US CVC placement compared to the landmark technique. The main perceived barriers to utilization of US guidance included lack of training and limited availability of US equipment and sterile sheaths. Conclusion: Perceived barriers to US-guided CVC placement in our population closely mirrored those found among North American physicians, including lack of training and limited availability of US machines and equipment. These barriers have the potential to be addressed by targeted educational and administrative interventions

International Scope of Emergency Ultrasound: Barriers in Applying Ultrasound to Guide Central Line Placement by Providers in Nairobi, Kenya

Background While ultrasound (US) use for internal jugular central venous catheter (CVC) placement is standard of care in North America, most developing countries have not adopted this practice. Previous surveys of North American physicians have identified lack of training and equipment availability as the most important barriers to the use of US. Go to: Objective We sought to identify perceived barriers to the use of US to guide CVC insertion in a resource-constrained environment. Go to: Methods Prior to an US-guided CVC placement training course conducted at the Aga Khan University Hospital in Nairobi, Kenya, physicians were asked to complete a survey to determine previous experience and perceived barriers. Survey responses were analyzed using summary statistics and the Rank-Sum test based on different specialty, gender, and previous US experience. Go to: Results There were 23 physicians who completed the course and the survey. 52% (95% CI: 0.30–0.73) had put in \u3e20 CVCs. 21.7% (95% CI: 0.08–0.44) of participants had previous US training, but none in the use of US for CVC insertion. The respondents expressed agreement with statements describing the ease of the use and improved success rate with US guidance. There was less agreement to statements describing the relative convenience and cost effectiveness of US CVC placement compared to the landmark technique. The main perceived barriers to utilization of US guidance included lack of training and limited availability of US equipment and sterile sheaths. Go to: Conclusion Perceived barriers to US-guided CVC placement in our population closely mirrored those found among North American physicians, including lack of training and limited availability of US machines and equipment. These barriers have the potential to be addressed by targeted educational and administrative interventions