2,497 publications from this institution
Recent improvements in processor implementation have focused attention on clock generation and distribution. The clocks and the latches connected to them must be carefully engineered to meet the performance requirements of the system. The author reports on the difficulty encountered in generating clocks for current processors, and describes techniques used to create these clocks, including minimizing both the internal clock skew and the skew between the internal logic and the external world. On-chip clock distribution, zero delay buffers, and self-timed systems are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Peter Gotzsche and John Ioannidis argue that it is not always sensible to include subject experts as authors of systematic reviews and meta-analyses
ABSTRACT Objective Death data from cohorts of academicians have been used to estimate pandemic excess deaths. We aimed to evaluate the validity of this approach. Study design and setting Data were analyzed from living and deceased member lists from Mainland China, UK and Greece academies; and Nobel laureates (and US subset thereof). Samples of early elected academicians were probed for unrecorded deaths; datasets overtly missing deaths were excluded from further analyses. Actuarial risks were compared against the general population in the same country in respective age strata. Relative incidence risk increases in death in active pandemic periods were compared to population-wide pandemic excess death estimates for the same country. Results Royal Society and Academy of Athens datasets overtly missed deaths. Pre-pandemic death rates were 4-12-fold lower in the Chinese Academy of Engineering (CAE) versus respective age strata of the Mainland China population. A +158% relative increase in death risk was seen in CAE data during the first 12-months of wide viral spread. Both increases (+34% in British Academy) and decreases (-27% in US Nobel laureates) in death rates occurred in pandemic (2020-22) versus pre-pandemic (2017-2019) years; point estimates were far from known excess deaths in the respective countries (+6% and +14%, respectively). Published excess death estimates for urban-dwelling Mainland China selectively analyzed CAE, but not another Chinese academy (Chinese Academy of Sciences) with half the pandemic death rates. Conclusion Missingness, lack of representativeness, large uncertainty, and selective analysis reporting make data from academy rosters unreliable for estimating general population excess deaths.
The available data are limited by their nonrandomized design, but overall they do not suggest that a healthcare facility's teaching status on its own markedly improves or worsens patient outcomes. Differences for specific diseases cannot be excluded, but are likely to be small.
All network devices must parse packet headers to decide how packets should be processed. A 64 × 10Gb/s Ethernet switch must parse one billion packets per second to extract fields used in forwarding decisions. Although a necessary part of all switch hardware, very little has been written on parser design and the trade-offs between different designs. Is it better to design one fast parser, or several slow parsers? What is the cost of making the parser reconfigurable in the field? What design decisions most impact power and area? In this paper, we describe trade-offs in parser design, identify design principles for switch and router designers, and describe a parser generator that outputs synthesizable Verilog that is available for download. We show that i) packet parsers today occupy about 1-2% of the chip, and ii) while future packet parsers will need to be programmable, this only doubles the (already small) area needed.
Catheter Ablation of Ligament of Marshall Tissue. Introduction: The ligament of Marshall is a left atrial neuromuscular bundle with sympathetic innervation that may be a source of atrial fibrillation (AF)‐inducing automatic activity. Methods and Results: Twenty‐four patients with paroxysmal AF (including 18 with adrenergic AF) and 25 with other arrhythmias underwent catheter mapping. In cases of adrenergic AF, radiofrequency ablation was attempted when Marshall potentials were recorded. Patients were followed for 2 months before and 11.2 ± 4.2 months after the procedure. Catheterization of the distal superoposterior coronary sinus was feasible in 14 patients with AF (10 with adrenergic AF) and 12 patients without AF. A discrete Marshall potential was recorded in 12 patients with AF versus 3 patients without AF ( P = 0.004 ). In 10 patients with adrenergic AF, this potential followed the atrial electrogram during sinus rhythm by 26 ± 5 msec on left atrial recordings and 24 ± 4 msec on coronary sinus recordings, and preceded it during atrial ectopy by 29 ± 5 msec and 26 ± 5 msec , respectively. It was abolished by epicardial ( n = 1 ), endocardial ( n = 4 ), or combined epicardial and endocardial ablation ( n = 5 ). Seven patients with ablation showed significant reductions in adrenergic AF, whereas no significant change was seen in 8 adrenergic AF patients not undergoing ablation ( P = 0.004 ). No improvement was seen in 3 of 4 patients with only endocardial ablation, whereas all 6 patients with epicardial ablation improved ( P = 0.033 ). Conclusion: Recording of Marshall potential is feasible in patients with paroxysmal AF. Combined epicardial and endocardial catheter ablation of ligament of Marshall tissue may reduce the paroxysms of adrenergic AF.
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