Dynamic Prediction of Architectural Vulnerability From Microarchitectural State Abstract

Transient faults due to particle strikes are a key challenge in microprocessor design. Driven by exponentially increasing transistor counts, per-chip faults are a growing burden. To protect against soft errors, redundancy techniques such as redundant multithreading (RMT) are often used. However, these techniques assume that the probability that a structural fault will result in a soft error (i.e., the Architectural Vulnerability Factor (AVF)) is 100 percent, unnecessarily draining processor resources. Due to the high cost of redundancy, there have been efforts to throttle RMT at runtime. To date, these methods have not incorporated an AVF model and therefore tend to be ad hoc. Unfortunately, computing the AVF of complex microprocessor structures (e.g., the ISQ) can be quite involved. To provide probabilistic guarantees about fault tolerance, we have created a rigorous characterization of AVF behavior that can be easily implemented in hardware. We experimentally demonstrate AVF variability within and across the SPEC2000 benchmarks and identify strong correlations between structural AVF values and a small set of processor metrics. Using these simple indicators as predictors, we create a proof-of-concept RMT implementation that demonstrates that AVF prediction can be used to maintain a low fault tolerance level without significant performance impact. 1

Defibrillation effectiveness and safety of the shock waveform used in a contemporary wearable cardioverter defibrillator: Results from animal and human studies.

IntroductionThe wearable cardioverter defibrillator (WCD) is used to protect patients at risk for sudden cardiac arrest. We examined defibrillation efficacy and safety of a biphasic truncated exponential waveform designed for use in a contemporary WCD in three animal studies and a human study.MethodsAnimal (swine) studies: #1: Efficacy comparison of a 170J BTE waveform (SHOCK A) to a 150J BTE waveform (SHOCK B) that approximates another commercially available waveform. Primary endpoint first shock success rate. #2: Efficacy comparison of the two waveforms at attenuated charge voltages in swine at three prespecified impedances. Primary endpoint first shock success rate. #3: Safety comparison of SHOCK A and SHOCK B in swine. Primary endpoint cardiac biomarker level changes baseline to 6 and 24 hours post-shock. Human Study: Efficacy comparison of SHOCK A to prespecified goal and safety evaluation. Primary endpoint cumulative first and second shock success rate. Safety endpoint adverse events.ResultsAnimal Studies #1: 120 VF episodes in six swine. First shock success rates for SHOCK A and SHOCK B were 100%; SHOCK A non-inferior to SHOCK B (entire 95% CI of rate difference above -10% margin, p ConclusionsThe BTE waveform effectively and safely terminated induced VF in swine and a small sample in humans.Trial registrationHuman study clinical trial registration: URL: https://clinicaltrials.gov; Unique identifier: NCT04132466

Mast Cell Stabilization Decreases Cardiomyocyte and LV Function in Dogs with Isolated Mitral Regurgitation.

BACKGROUND: Mast cells are increased in isolated mitral regurgitation (MR) in the dog and may mediate extracellular matrix loss and left ventricular (LV) dilatation. We tested the hypothesis that mast cell stabilization would attenuate LV remodeling and improve function in the MR dog. METHODS AND RESULTS: MR was induced in adult dogs randomized to no treatment (MR, n = 5) or to the mast cell stabilizer, ketotifen (MR + MCS, n = 4) for 4 months. LV hemodynamics were obtained at baseline and after 4 months of MR and magnetic resonance imaging (MRI) was performed at sacrifice. MRI-derived, serial, short-axis LV end-diastolic (ED) and end-systolic (ES) volumes, LVED volume/mass ratio, and LV 3-dimensional radius/wall thickness were increased in MR and MR + MCS dogs compared with normal dogs (n = 6) (P \u3c .05). Interstitial collagen was decreased by 30% in both MR and MR + MCS versus normal dogs (P \u3c .05). LV contractility by LV maximum time-varying elastance was significantly depressed in MR and MR + MCS dogs. Furthermore, cardiomyocyte fractional shortening was decreased in MR versus normal dogs and further depressed in MR + MCS dogs (P \u3c .05). In vitro administration of ketotifen to normal cardiomyocytes also significantly decreased fractional shortening and calcium transients. CONCLUSIONS: Chronic mast cell stabilization did not attenuate eccentric LV remodeling or collagen loss in MR. However, MCS therapy had a detrimental effect on LV function because of a direct negative inotropic effect on cardiomyocyte function

A methodology for calculating the spatial distribution of the area-slope equation and the hypsometric integral within a catchment

The area-slope relationship and the hypsometric curve are well known catchment descriptors. The main shortcoming of traditional area-slope and hypsometry extraction methods is their limited ability to represent heterogeneity within the catchment. Here we present a new methodology for explicit calculation of the spatial distribution, at a pixel scale within a catchment, of the area-slope parameters and the hypsometric integral. This method allows us to create a quantitative representation of the area-slope equation and the hypsometric integral which can potentially be used in a variety of geomorphologic applications. The results show that the spatial distribution of both the area-slope equation and the hypsometric integral are noisy at the pixel scale. In order to reduce the noise three averaging techniques were examined. Subcatchment-scale averaging was found to be the best at identifying the spatial distribution of the area-slope equation and hypsometric integral. At the subcatchment scale the spatial distribution of the area-slope equation and the hypsometric integral approximated the spatial distribution of soil morphological and geological units of the Goulburn River catchment in eastern Australia. The spatially distributed area-slope results were tested using manually extracted subcatchment average area-slope values and found to be well correlated. The spatially distributed hypsometric integral was also well correlated with landform concavity and convergence. The subcatchment-scale averaging of the spatially distributed area-slope equation and hypsometric integral is shown to be a promising tool for producing spatially distributed data. The techniques are demonstrated on a catchment that has marked spatial variation in soils and geology. The results show that the spatially explicit maps can potentially identify the spatial extent of these soil types and geological features and agrees well with existing soil maps

Marking out the pitch: a historiography and taxonomy of football fiction

Football, or soccer as it is more commonly referred to in Australia and the US, is arguably the world’s most popular sport. It generates a proportionate volume of related writing. Within this landscape, works of novel-length fiction are seemingly rare. This paper establishes and maps a substantial body of football fiction works, explores elements and qualities exhibited individually and collectively. In bringing together current, limited surveys of the field, it presents the first rigorous definition of football fiction and captures the first historiography of the corpus. Drawing on distant reading methods developed in conjunction with closer textual analyses, the historiography and subsequent taxonomy represent the first articulation of relationships across the body of work, identify growth areas and establish a number of movements and trends. In advancing the understanding of football fiction as a collective body, the paper lays foundations for further research and consideration of the works in generic terms

Chymase Inhibition Prevents Fibronectin and Myofibrillar Loss and Improves Cardiomyocyte Function and LV Torsion Angle in Dogs with Isolated Mitral Regurgitation.

BACKGROUND: The left ventricular (LV) dilatation of isolated mitral regurgitation (MR) is associated with an increase in chymase and a decrease in interstitial collagen and extracellular matrix. In addition to profibrotic effects, chymase has significant antifibrotic actions because it activates matrix metalloproteinases and kallikrein and degrades fibronectin. Thus, we hypothesize that chymase inhibitor (CI) will attenuate extracellular matrix loss and LV remodeling in MR. METHODS AND RESULTS: We studied dogs with 4 months of untreated MR (MR; n=9) or MR treated with CI (MR+CI; n=8). Cine MRI demonstrated a \u3e40% increase in LV end-diastolic volume in both groups, consistent with a failure of CI to improve a 25% decrease in interstitial collagen in MR. However, LV cardiomyocyte fractional shortening was decreased in MR versus normal dogs (3.71±0.24% versus 4.81±0.31%; P CONCLUSIONS: These results suggest that chymase disrupts cell surface-fibronectin connections and FAK phosphorylation that can adversely affect cardiomyocyte myofibrillar structure and function. The greater effect of CI on epicardial versus endocardial titin and noncollagen cell surface proteins may be responsible for the increase in torsion angle in chronic MR