The storage capacities and areal densities found in magnetic disk drives are increasing very rapidly. Data is recorded in ever-narrower tracks which must be followed with extreme precision. Also, the ...advent of portable applications exposes these smaller drives to higher levels of vibration and shock. A description is given of the many factors which contribute to recording track misregistration (TMR) in today's drives. The mechanics of the drive and actuator and the architecture of the servo control system are also described. A projection is made for the TMR sensitivities and control system at an areal density of 10 Gb/in/sup 2/, having roughly 25000 tracks/in. A two-stage servo may be needed to achieve such track densities. This would comprise a high bandwidth microactuator for rapid position corrections of the recording head, coupled with a conventional actuator. The characteristics of such a microactuator are discussed, and operational examples of fabricated electroplated microactuators, driven electrostatically, are shown. The mechanical behavior of the devices and some of the factors which would affect their implementation are also described.< >
Tests were performed with the freshwater invertebrates Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus to determine the acute toxicity of six phthalate esters, including dimethyl ...phthalate (DMP), diethyl phthalate (DEP), di‐n‐butyl phthalate (DBP), butylbenzyl phthalate (BBP), di‐n‐hexyl phthalate (DHP), and di‐2‐ethylhexyl phthalate (DEHP). It was possible to derive 10‐d LC50 (lethal concentration for 50% of the population) values only for the four lower molecular weight esters (DMP, DEP, DBP, and BBP), for which toxicity increased with increasing octanol–water partition coefficient (Kow) and decreasing water solubility. The LC50 values for DMP, DEP, DBP, and BBP were 28.1, 4.21, 0.63, and 0.46 mg/L for H. azteca; 68.2, 31.0, 2.64, and > 1.76 mg/L for C. tentans; and 246, 102, 2.48, and 1.23 mg/L for L. variegatus, respectively. No significant survival reductions were observed when the three species were exposed to either DHP or DEHP at concentrations approximating their water solubilities.
Objectives
The duration of urethral stenting after tubularized incised plate (TIP) urethroplasty for hypospadias varies among surgeons. Typically the catheter is left for up to 7 days with the goal ...of minimizing post-operative complications. We describe our experience with overnight stenting for distal TIP hypospadias repair.
Materials and methods
A retrospective chart review was performed on patients who underwent TIP hypospadias repair from 2003 to 2008. Patients who had their urethral catheter overnight were included in this analysis. Outcomes analyzed were the rates of: urethrocutaneous fistula, meatal stenosis, urethral stricture and urinary tract infections.
Results
A total of 64 patients underwent outpatient TIP hypospadias repair. Forty-nine patients had overnight urethral stenting with at least 12 months follow-up and were included in the analysis. Five of the 49 patients (10.2%) developed urethrocutaneous fistula. Of these five patients, two had undergone re-do hypospadias repair. The fistula rate in primary repairs was 3/45 (6.7%). There were no incidences of meatal stenosis, urinary tract infections or urethral strictures.
Conclusion
In our experience, overnight urethral stenting for TIP hypospadias repair does not significantly affect the rates of urethrocutaneous fistula, meatal stenosis and urinary tract infections. Patients who have had a primary TIP hypospadias repair may have their urethral catheter removed safely on post-operative day one.
The authors' welcome Dan Levin's comment as a nice example of the manner in which they believe science should ideally proceed. But the authors' wish to raise three concerns with Levin's proposal. ...First, Levin fails to consider whether his Nash equilibrium holds in the multi-unit Vickery auction as well as in the uniform-price auction. In order to explain the experimentally observed, his theory should predict differences in equilibrium bidding behavior across the two auction formats. To address this, the authors will evaluate the existence and other properties of his equilibrium in the Vickery's auction format. Second, they temper Levin's claims that his equilibrium generally provides higher efficiency and higher bidder's surplus than the EWK equilibrium does. Third, they show that given the empirical distribution of bids in the experiment, a bidder has a good reason not to follow Levin's prescription of bidding above value on the first unit.
Seven phthalate esters were evaluated for their 10‐d toxicity to the freshwater invertebrates Hyalella azteca and Chironomus tentans in sediment. The esters were diethyl phthalate (DEP), di‐n‐butyl ...phthalate (DBP), di‐n‐hexyl phthalate (DHP), di‐(2‐ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and a commercial mixture of C7, C9, and C11 isophthalate esters (711P). All seven esters were tested in a sediment containing 4.80% total organic carbon (TOC), and DBP alone was tested in two additional sediments with 2.45 and 14.1% TOC. Sediment spiking concentrations for DEP and DBP were based on LC50 (lethal concentration for 50% of the population) values from water‐only toxicity tests, sediment organic carbon concentration, and equilibrium partitioning (EqP) theory. The five higher molecular weight phthalate esters (DHP, DEHP, DINP, DIDP, 711P), two of which were tested and found to be nontoxic in water‐only tests (i.e., DHP and DEHP), were tested at single concentrations between 2,100 and 3,200 mg/kg dry weight. Preliminary spiking studies were performed to assess phthalate ester stability under test conditions. The five higher molecular weight phthalate esters in sediment had no effect on survival or growth of either C. tentans or H. azteca, consistent with predictions based on water‐only tests and EqP theory. The 10‐d LC50 values for DBP and H. azteca were >17,400, >29,500, and >71,900 mg/kg dry weight for the low, medium, and high TOC sediments, respectively. These values are more than 30× greater than predicted by EqP theory and may reflect the fact that H. azteca is an epibenthic species and not an obligative burrower. The 10‐d LC50 values for DBP and C. tentans were 826, 1,664, and 4,730 mg/kg dry weight for the low, medium, and high TOC sediments, respectively. These values are within a factor of two of the values predicted by EqP theory. Pore‐water 10‐d LC50 values for DBP (dissolved fraction) and C. tentans in the three sediments were 0.65, 0.89, and 0.66 of the water‐only LC50 value of 2.64 mg/L, thereby agreeing with EqP theory predictions to within a factor of 1.5. The LC50 value for DEP and C. tentans was >3,100 mg/kg dry weight, which is approximately 10× that predicted by EqP theory. It is postulated that test chemical loss and reduced organism exposure to pore water may have accounted for the observed discrepancies with EqP calculations for DEP.
Monitoring risk-adjusted outcomes is the centerpiece of efforts to ensure health care quality. Because data collection is expensive, questions arise concerning what information is essential to adjust ...for risk. This investigation used retrospective analysis of existing, computerized clinical databases containing laboratory test results, information on chronic coexisting conditions, and nursing evaluations of functional status to predict in-hospital mortality. We studied persons admitted to one tertiary teaching hospital between 1987 and 1992 for cerebrovascular disease or pneumonia. Predictive models for each of the conditions were developed using logistic regression; the results were validated with split samples. We compared the predictive value of the nursing functional status assessments and the clinical laboratory data. For each study condition, the functional status data had as much prognostic information as the laboratory data. Specifically, a nurse's report that a patient required total assistance for bathing was the best single predictor of in-hospital mortality in the models for patients with either cerebrovascular disease or pneumonia. If hospitals admit patients with different levels of functional impairment, it is important to account for these differences before comparing outcomes across facilities. Assessments of functional status are a simple, inexpensive measure that may have considerable value.
Enabling Multithreading on CGRAs Shrivastava, A.; Pager, J.; Jeyapaul, R. ...
2011 International Conference on Parallel Processing,
2011-Sept.
Conference Proceeding
Coarse-Grained Reconfigurable Arrays or CGRAs are programmable fabrics that promise both high performance and high power efficiency. Traditionally, CGRAs were used to accelerate extremely-embedded ...systems, and were typically manually programmed. However, as CGRAs are conceived to be used as more general-purpose accelerators, there is a need to develop software tools and capabilities. Much work has been done on developing compiler techniques for CGRAs, making programming them easier, however, there is no support for multithreading. As an accelerator to a multithreaded processor, CGRAs now are restricted to accelerating only one kernel of one thread running on the processor at any point in time. Supporting multithreading is difficult, since the start times and end times of threads are dynamic in nature, while CGRAs are statically scheduled. In this paper, we propose a strategy to do multithreading on a CGRA. The chief capability that we develop is a scheme to quickly transform an existing application mapping using the entire CGRA to one using only a fraction of it. Our experimental results on kernels from multimedia applications demonstrate that multithreading support can improve the total throughput of a CGRA by over 30%, 75%, and 150% on 4×4, 6×6, and 8×8 CGRAs, respectively, compared to single-threaded methods.
We present the first absolute calibration for the yellow post-asymptotic-giant-branch (PAGB) stars in the g- and r-band based on time-series observations from the Zwicky Transient Facility. These ...absolute magnitudes were calibrated using four yellow PAGB stars (one non-varying star and three Type II Cepheids) located in the globular clusters. We provide two calibrations of the gr-band absolute magnitudes for the yellow PAGB stars, by using an arithmetic mean and a linear regression. We demonstrate that the linear regression provides a better fit to the g-band absolute magnitudes for the yellow PAGB stars. These calibrated gr-band absolute magnitudes have a potential to be used as population II distance indicators in the era of time-domain synoptic sky surveys.
PDF
