731 research outputs found
Revisiting Old Friends: Is CoDel Really Achieving What RED Cannot?
We use ns-2 simulations to compare RED's gentle mode to CoDel in terms of their ability to reduce the latency for various TCP variants. We use a common dumbbell topology with Pareto background traffic, and measure the packet delays and transmission time of a 10MB FTP transfer.
In our scenarios, we find that CoDel reduces the latency by 87%, but RED still manages to reduce it by 75%. However, the use of CoDel results in a transmission time 42% longer than when using RED. In light of its maturity, we therefore argue that RED could be considered as a good candidate to tackle Bufferbloat
Status of SuperSpec: A Broadband, On-Chip Millimeter-Wave Spectrometer
SuperSpec is a novel on-chip spectrometer we are developing for multi-object,
moderate resolution (R = 100 - 500), large bandwidth (~1.65:1) submillimeter
and millimeter survey spectroscopy of high-redshift galaxies. The spectrometer
employs a filter bank architecture, and consists of a series of half-wave
resonators formed by lithographically-patterned superconducting transmission
lines. The signal power admitted by each resonator is detected by a lumped
element titanium nitride (TiN) kinetic inductance detector (KID) operating at
100-200 MHz. We have tested a new prototype device that is more sensitive than
previous devices, and easier to fabricate. We present a characterization of a
representative R=282 channel at f = 236 GHz, including measurements of the
spectrometer detection efficiency, the detector responsivity over a large range
of optical loading, and the full system optical efficiency. We outline future
improvements to the current system that we expect will enable construction of a
photon-noise-limited R=100 filter bank, appropriate for a line intensity
mapping experiment targeting the [CII] 158 micron transition during the Epoch
of ReionizationComment: 16 pages, 10 figures, Proceedings of the SPIE Astronomical Telescopes
+ Instrumentation 2014 Conference, Vol 9153, Millimeter, Submillimeter, and
Far-Infrared Detectors and Instrumentation for Astronomy VI
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Double-shell tank space analysis of Hanford Site operating scenarios
Several operating cases were evaluated to determine the Hanford Site activities that can be supported given two 242-A Evaporator operating assumption: (1) the evaporator does not restart and (2) the evaporator does not restart until December 1990. These cases included variation in production facility operation and Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) commitments. The cases that evaluated the no evaporator restart'' operating assumptions determined that even the minimal double-shell tank waste generating activities cannot be supported. For the minimal waste generation rate, double-shell tank space would be depleted by December 1991. The cases that evaluated the evaporator restart would support all production mission with the exception of the plutonium-uranium extraction (PUREX) processing. A delay in the evaporator restart and/or increased waste generation could significantly impact the above conclusions. Actions to reduce waste generation rates, minimize stored volumes in the double-shell tanks, and optimize use of double-shell tanks must be pursued. 1 ref., 8 figs
A review of ureteral injuries after external trauma
<p>Abstract</p> <p>Introduction</p> <p>Ureteral trauma is rare, accounting for less than 1% of all urologic traumas. However, a missed ureteral injury can result in significant morbidity and mortality. The purpose of this article is to review the literature since 1961 with the primary objective to present the largest medical literature review, to date, regarding ureteral trauma. Several anatomic and physiologic considerations are paramount regarding ureteral injuries management.</p> <p>Literature review</p> <p>Eighty-one articles pertaining to traumatic ureteral injuries were reviewed. Data from these studies were compiled and analyzed. The majority of the study population was young males. The proximal ureter was the most frequently injured portion. Associated injuries were present in 90.4% of patients. Admission urinalysis demonstrated hematuria in only 44.4% patients. Intravenous ureterogram (IVU) failed to diagnose ureteral injuries either upon admission or in the operating room in 42.8% of cases. Ureteroureterostomy, with or without indwelling stent, was the surgical procedure of choice for both trauma surgeons and urologists (59%). Complications occurred in 36.2% of cases. The mortality rate was 17%.</p> <p>Conclusion</p> <p>The mechanism for ureteral injuries in adults is more commonly penetrating than blunt. The upper third of the ureter is more often injured than the middle and lower thirds. Associated injuries are frequently present. CT scan and retrograde pyelography accurately identify ureteral injuries when performed together. Ureteroureterostomy, with or without indwelling stent, is the surgical procedure of choice of both trauma surgeons and urologists alike. Delay in diagnosis is correlated with a poor prognosis.</p
From the cell membrane to the nucleus: unearthing transport mechanisms for Dynein
Mutations in the motor protein cytoplasmic dynein have been found to cause Charcot-Marie-Tooth disease, spinal muscular atrophy, and severe intellectual disabilities in humans. In mouse models, neurodegeneration is observed. We sought to develop a novel model which could incorporate the effects of mutations on distance travelled and velocity. A mechanical model for the dynein mediated transport of endosomes is derived from first principles and solved numerically. The effects of variations in model parameter values are analysed to find those that have a significant impact on velocity and distance travelled. The model successfully describes the processivity of dynein and matches qualitatively the velocity profiles observed in experiments
Fast resistive bolometry
Resistive bolometry is an accurate, robust, spectrally broadband technique for measuring absolute x-ray fluence and flux. Bolometry is an independent technique for x-ray measurements that is based on a different set of physical properties than other diagnostics such as x-ray diodes, photoconducting detectors, and P-I-N diodes. Bolometers use the temperature-driven change in element resistivity to determine the total deposited energy. The calibration of such a device is based on fundamental material properties and its physical dimensions. We describe the use of nickel and gold bolometers to measure x rays generated by high-power z pinches on Sandia's Saturn and Z accelerators. The Sandia bolometer design described herein has a pulse response of {approximately}1 ns. We describe in detail the fabrication, fielding, and data analysis issues leading to highly accurate x-ray measurements. The fundamental accuracy of resistive bolometry will be discussed
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