LocationSpark: In-memory Distributed Spatial Query Processing and Optimization.

Due to the ubiquity of spatial data applications and the large amounts of spatial data that these applications generate and process, there is a pressing need for scalable spatial query processing. In this paper, we present new techniques for spatial query processing and optimization in an in-memory and distributed setup to address scalability. More specifically, we introduce new techniques for handling query skew that commonly happens in practice, and minimizes communication costs accordingly. We propose a distributed query scheduler that uses a new cost model to minimize the cost of spatial query processing. The scheduler generates query execution plans that minimize the effect of query skew. The query scheduler utilizes new spatial indexing techniques based on bitmap filters to forward queries to the appropriate local nodes. Each local computation node is responsible for optimizing and selecting its best local query execution plan based on the indexes and the nature of the spatial queries in that node. All the proposed spatial query processing and optimization techniques are prototyped inside Spark, a distributed memory-based computation system. Our prototype system is termed LocationSpark. The experimental study is based on real datasets and demonstrates that LocationSpark can enhance distributed spatial query processing by up to an order of magnitude over existing in-memory and distributed spatial systems.

Comparison of intubation success of video laryngoscopy versus direct laryngoscopy in the difficult airway using high-fidelity simulation.

INTRODUCTION: A number of devices, including video laryngoscopy, are used to aid in managing difficult airways. The goal of this study was to compare timing and success of video laryngoscopy to standard laryngoscopic intubation using a simulation mannequin in normal and difficult airway scenarios. METHODS: Residents and attending physicians of a PGY 2-4 emergency medicine residency program participated. A single, high-fidelity simulation mannequin was used. Each participant received an in-service on the video laryngoscope (GlideScope). Three airway settings were used: standard, decreased neck mobility, and tongue edema. Participants intubated with a Macintosh blade and video laryngoscope in each scenario, and graded the best view achieved using the Cormack-Lehane classification. Outcome measures included time to view the vocal cords, time to intubation, grading of view, and intubation success or failure. Institutional Review Board approval was obtained. RESULTS: Fifty-two participants were enrolled. Participants successfully intubated the mannequin faster using the Macintosh blade in both the normal and neck immobility settings (9.4 seconds faster, 95% CI 3.2-15.7, P = 0.004, 16.1 seconds faster, 95% CI 3.6-28.7, P = 0.01). In the tongue edema setting, however, video laryngoscopy provided a better grade view of the cords, a higher success rate of viewing the cords at time of intubation (50% vs. 12%), and a higher rate of successful intubations (83% vs. 23%). The GlideScope also significantly reduced the time needed to view the cords (89 seconds reduction, 95% CI 54.4-123.7, P < 0.0001) and intubate (131.3 seconds reduction, 95% CI 99.1-163.6, P< 0.0001) for the tongue edema setting. CONCLUSIONS: In the most difficult airway case, tongue edema, the video laryngoscope provided an enhanced view of the cords using less time, increased intubation success, and decreased the time to intubation.

Diagnosis and management of the acute red eye.

The red eye is one of the most frequent presenting complaints in the emergency department setting. A wide spectrum of disease processes may present as a red eye, ranging from benign self-limiting etiologies to serious vision-threatening ones. The emergency physician must be adept at recognizing "red flags" from the history and physical examination that necessitate immediate treatment and referral. In addition, it is imperative for the emergency physician to recognize the need for immediate versus elective ophthalmologist consultation for the various conditions. This article includes a discussion of the key historical features, clinical presentations, physical examination findings, and management of the more common causes of the red eye.