97 research outputs found
Cell Tracking using a Distributed Algorithm for 3D Image Segmentation
We have developed and tested an automated method for simultaneous 3D tracking of numerous, flourescently-tagged cells. The procedure uses multiple thresholding to segment individual cells at a starting timepoint, and then iteratively applies a template-matching algorithm to locate a particular cell\u27s position at subsequent time points. To speed up the method, we have developed a distributed implementation in which template matching is carried out in parallel on several different server machines. The distributed implementation showed a monotonic decrease in response time with increasing number of servers (up to 15 tested), demonstrating that the tracking algorithm is well suited to parallelization, and that nearly real-time performance could be expected on a parallel processor. Of four different template matching statistics tested for 3D tracking of amebae from the cellular slime mold Dictyostelium discoideum, we found that the automated procedure performed best when using a correlation statistic for matching. Using this statistic, the method achieved a .985% success rate in correctly identifying a cell from one timepoint to the next. This method is now being used regularly for 3D tracking of normal and mutant cells of D. discoideum, and as such provides a means to quantify the motion of many cells within a three-dimensional tissue mass
Hardware Based Error and Flow Control in the Axon Gigabit Host-Network Interface
We have proposed a new architecture called Axon that meets the challenges of delivering high performance network bandwidth directly to applications. Its pipelines network interface must perform critical per packet processing in hardware a packets flow through the pipeline, without imposing any store-and-forward buffering of packets. This requires the design of error and flow control mechanisms to be simple enough for implementation in the network interface hardware, while providing functionality required by applications. This paper describes the implementation of the Axon host-network interface, and in particular the hardware design of the critical per packet processing with emphasis on error and flow control. An extensive simulation model of the network interface hardware has been used to determine the feasibility and performance of hardware implementation of these functions
Autonomic neuropathy predisposes to rosiglitazone-induced vascular leakage in insulin-treated patients with type 2 diabetes: a randomised, controlled trial on thiazolidinedione-induced vascular leakage
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88447.pdf (publisher's version ) (Closed access)AIMS/HYPOTHESIS: The mechanism of fluid-related complications caused by thiazolidinedione derivatives is unclear. One potential mechanism is thiazolidinedione-induced arterial vasodilatation, which results in vascular leakage and a fall in blood pressure, normally counterbalanced by sympathetic activation and subsequent renal fluid retention. We hypothesised that thiazolidinedione-induced vascular leakage will be particularly prominent in patients with autonomic neuropathy. METHODS: We conducted a randomised, double-blind, placebo-controlled, parallel study in 40 patients with type 2 diabetes on insulin treatment recruited from a university medical centre. The randomisation was performed by a central office using a randomisation schedule. Both treatment groups, placebo (n = 21) and rosiglitazone (n = 19), were stratified for sex and level of autonomic neuropathy as assessed by Ewing score (or=2.5). We investigated the effects of 16 weeks of treatment with rosiglitazone 4 mg twice daily on vascular leakage (transcapillary escape rate of albumin, TERalb), body weight, extracellular volume and plasma volume. RESULTS: Thirty-nine patients were included in the analysis. In patients with high Ewing scores (n = 16), rosiglitazone increased TERalb significantly (DeltaTERalb: rosiglitazone +2.43 +/- 0.45%/h, placebo -0.11 +/- 0.15%/h, p = 0.002), while rosiglitazone had no effect in the patients with low Ewing scores (n = 23). Rosiglitazone-induced increases in TERalb and Ewing score at baseline were correlated (r = 0.65, p = 0.02). There was no correlation between Ewing score and rosiglitazone-induced changes in fluid variables. One subject was withdrawn from the study because of atrial fibrillation. CONCLUSIONS/INTERPRETATION: Rosiglitazone may increase vascular leakage in insulin-treated patients with type 2 diabetes with autonomic neuropathy. Autonomic neuropathy did not exaggerate rosiglitazone-induced fluid retention. Therefore, autonomic neuropathy should be considered as a risk factor for thiazolidinedione-induced oedema, not for thiazolidinedione-induced fluid retention. TRIAL REGISTRATION: ClinicalTrials.gov NCT00422955. FUNDING: GlaxoSmithKline.1 september 201
Bringing Real-time Scheduling Theory and Practice Closer for Multimedia Computing
This paper seeks to bridge the gap between theory and practice of real-time scheduling in the domain of high speed multimedia networking. We show that the strict preemptive nature of real-time scheduling leads to more context switching, and requires system calls for concurrency control. We present our scheduling scheme called rate-monotonic with delayed preemption (rmdp) and show how it reduces both these overheads. We then develop the analytical framework to analyze rmdp and other scheduling schemes that lie in the region between strict (immediate) preemption and no preemption. Our idealized scheduler simulation methodology accounts for the blocking introduced by these schemes under the usual assumption that the time for context switching and preemption is zero. We derive simpler schedulability tests for non-preemptive scheduling, and prove a variant of rate-monotonic scheduling that has fewer preemptions. Our measurements on Sparc and Pentium platforms, show that for the workloads w..
An Implementation Model for Connection-Oriented Internet Protocols
Recently a number of research groups have proposed connection-oriented access protocols that can provide a variable grade of service with performance guarantees on top of diverse networks. These connectionoriented internet protocols (coips) have performance trade-offs. A COIP-Kernel which can be used as a toolkit to implement any of the proposed coips has been designed. Coip-k features module interchange and incremental software support. The paper presents the coip-k implementation and its performance characteristics.
Technical aspects of impedance plethysmography.
This paper describes the basic methods for measurement of body impedance, electrodes and their configuration, and the measuring instrument with its limitations. A microcomputer assisted impedance plethysmograph system, developed at BARC and different lead configurations for impedance plethysmographic investigation are also described. Typical impedance plethysmographic waveforms recorded from a normal subject and measurement of their amplitude and various time intervals are illustrated
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