Continuous Churn Research Articles

Churning the tides of care: when nurse turnover makes waves in patient access to primary care

BackgroundTeam-based primary care (PC) enhances the quality of and access to health care. The Veterans Health Administration (VHA) implements team-based care through Patient Aligned Care Teams (PACTs), consisting of four core members: a primary care provider, registered nurse (RN) care manager, licensed vocational nurse, and scheduling clerk. RNs play a central role: they coordinate patient care, manage operational needs, and serve as a patient point of contact. Currently, it is not known how varying levels of RN staffing on primary care teams impact patient outcomes.ObjectiveThis study aims to empirically assess how the stability of RN staffing within team-based primary care affects patient access to care.MethodsA retrospective database review using clinical and administrative data from the VHA over 24 months. Participants included 5,897 PC PACTs across 152 VHA healthcare facilities in the United States and its territories. The stability of personnel in the RN role was categorized as: RN continuous churn, RN staffing instability and RN vacancy. All 3 categories were compared to teams with RN stability (i.e., same person in the role for the entire 24-month period). Access measures included: average third-next-available appointment, established patient average wait time in days, urgent care utilization, emergency room utilization, and total inbound-to-outbound PC secure messages ratio.ResultsRN continuous churn within PACTs had a significant impact on third-next-available appointment (b = 3.70, p < 0.01). However, RN staffing instability and vacancy had no significant relationship with any of the access measures. Several risk adjustment variables, including team full-time equivalency, team stability, relative team size, and average team size, were significantly associated with access to health care.ConclusionsTeams are impacted by churn on the team. Adequate staffing and team stability significantly predict patient access primary care services. Healthcare organizations should focus on personnel retention and strategies to mitigate the impact(s) of continuous RN turnover. Future research should examine the relative impact of turnover and stability of other roles (e.g., clerks) and how team members adapt to personnel changes.

Landlord: Coordinating Dynamic Software Environments to Reduce Container Sprawl

Containers provide customizable software environments that are independent from the system on which they are deployed. Online services for task execution must often generate containers on the fly to meet user-generated requests. However, as the number of users grows and container environments are changed and updated over time, there is an explosion in the number of containers that must be managed, despite the fact that there is significant overlap among many of the containers in use. We analyze a trace of container launches on the public Binder service and demonstrate the performance and resource usage issues associated with container sprawl. We present <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Landlord</small> , an algorithm that coalesces related container environments, and show that it can improve container reuse and reduce the number of container builds required in the Binder trace by 40%. We perform a sensitivity analysis of <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Landlord</small> using randomized synthetic workloads on a high-energy physics (HEP) software repository and demonstrate that <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Landlord</small> shows benefits for container management across a wide range of usage patterns. Finally, we compare <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Landlord</small> to offline clustering, and observe that the continuous churn in software necessitates an online approach.

Store-collect in the presence of continuous churn with application to snapshots and lattice agreement

We present an algorithm for implementing a store-collect object in an asynchronous crash-prone message-passing dynamic system, where nodes continually enter and leave. The algorithm is very simple and efficient, requiring just one round trip for a store operation and two for a collect. We then show the versatility of the store-collect object for implementing churn-tolerant versions of useful data structures, while shielding the user from the complications of the underlying churn. In particular, we present elegant and efficient implementations of atomic snapshot and generalized lattice agreement objects that use store-collect.

Towards software defined low maintenance structured peer-to-peer overlays

Structured Peer-to-Peer (P2P) overlay networks are scalable and efficient networks. This efficiency comes at a cost as there is a need for regular maintenance of an overlay structure to handle the continuous churn of peers. This results in huge overhead in terms of maintenance traffic generated by peers. This problem becomes more critical when logical overlay topology differs from actual physical network topology, a common phenomenon in P2P overlay networks. In this paper, we present a novel approach to designing a Distributed Hash Table (DHT) based P2P overlays with the help of Software Defined Networks (SDN) concepts. SDN is an upcoming technology that provides enough flexibility in deciding application-specific network policies and rules dynamically. In our approach, we have attempted to bring the overlay topology closer to actual physical topology and reduce the maintenance traffic as much as possible. We have also tested our work on a hybrid network consisting of both virtual and physical switches. The experimental results suggest and establish the applicability of our approach.

Industrial Application of Different Heat Treatments and Cream Fat Contents for Improving the Spreadability of Butter.

Individual factors, which interfere in the continuous churning, were manipulated to enhance the rheological properties and chemical composition of butter. This process leads to achieve softer; more spreadable, and ultimately healthier product for consumers. In addition it could prevent hardening of texture especially in winter. Firstly, Pasteurized cream with different fat contents (40 & 45% fat) was passed through heat treatments, and then it was injected to a continuous churn. Textural and melting behavior and fatty acid composition of butter were analyzed. Increasing the fat content of cream (from 40 to 45 %) and holding time (from 3h to 5h) in mid-temperature (18 ºC) and reducing the churning temperature (from 12 ºC to 10 ºC), resulted in soft butter texture and improved butter spreadability. Loss Tangent (tan δ) was increased from 0.11 to 0.74 (T=15 ºC;f=1Hz). The melting temperature of butter was decreased from 36ºC to 32ºC and total trans fatty acid content was decreased from 3.2 % to 1.87 %. It was concluded that such heating process (which has been studied and reported in patents) absorbs the low- SFC fats of the cream, integrates them into the butter texture a softer and more spreadable product.

Implementing a Regular Register in an Eventually Synchronous Distributed System Prone to Continuous Churn

Due to their capability to hide the complexity generated by the messages exchanged between processes, shared objects are one of the main abstractions provided to developers of distributed applications. Implementations of such objects, in modern distributed systems, have to take into account the fact that almost all services, implemented on top of distributed infrastructures, are no longer fully managed due to either their size or their maintenance cost. Therefore, these infrastructures exhibit several autonomic behaviors in order to, for example, tolerate failures and continuous arrival and departure of nodes (churn phenomenon). Among all the shared objects, the register object is a fundamental one. Several protocols have been proposed to build fault resilient registers on top of message-passing system, but, unfortunately, failures are not the only challenge in modern distributed systems and new issues arise in the presence of churn. This paper addresses the construction of a multiwriter/multireader regular register in an eventually synchronous distributed system affected by the continuous arrival/departure of participants. In particular, a general protocol implementing a regular register is proposed and feasibility conditions associated with the arrival and departure of the processes are given. The protocol is proved correct under the assumption that a constraint on the churn is satisfied.