Research on Total Ionizing Dose Effect and Reinforcement of SOI-TFET

Since the oxide/source overlap structure can improve the tunneling probability and on-state current of tunneling field effect transistor (TFET) devices, and the silicon-on-insulator (SOI) structure has the effect of resisting the single event effect, SOI-TFET with the oxide/source overlap structure is a device with development potential. The total ionizing dose (TID) effect on SOI-TFET was studied by discussing the switching ratio, band–band tunneling rate, threshold voltage, sub-threshold swing and bipolar effect of the device under different doses of irradiation. At the same time, simulations prove that selecting the proper thickness of the buried oxide (BOX) layer can effectively reduce the influence of the TID effect. This provides a way of direction and method for research on the irradiation effects on the device in the future.

COPILOT: a Containerised wOrkflow for Processing ILlumina genOtyping daTa

Background: The Illumina genotyping microarrays generate data in image format, which is processed by the platform-specific software GenomeStudio, followed by an array of complex bioinformatics analyses. This process can be time-consuming, lead to reproducibility errors, and be a daunting task for novice bioinformaticians. Results: Here we introduce the COPILOT (Containerised wOrkflow for Processing ILlumina genOtyping daTa) protocol, which provides an in-depth and clear guide to process raw Illumina genotype data in GenomeStudio, followed by a containerised workflow to automate an array of complex bioinformatics analyses involved in a GWAS quality control (QC). The COPILOT protocol was applied to two independent cohorts consisting of 2791 and 479 samples genotyped on the Infinium Global Screening (GSA) array with Multi-disease (MD) drop-in (~750,000 markers) and the Infinium H3Africa consortium array (~2,200,000 markers) respectively. Following the COPILOT protocol, an average sample quality improvement of 1.24% was observed across sample call rates, with notable improvement for low-quality samples. For example, from the 3270 samples processed, 141 samples had an initial sample call rate below 98%, averaging 96.6% (95% CI 95.6-97.7%), which is considered below the acceptable sample call rate threshold for a typical GWAS analysis. However, following the COPILOT protocol, all 141 samples had a call rate above 98% after QC and averaged 99.6% (95% CI 99.5-99.7%). In addition, the COPILOT pipeline automatically identified potential data issues, including gender discrepancies, heterozygosity outliers, related individuals, and population outliers through ancestry estimation. Conclusions: The COPILOT protocol makes processing Illumina genotyping data transparent, effortless and reproducible. The container is deployable on multiple platforms, improves data quality, and the end product is analysis-ready PLINK formatted data, with a comprehensive and interactive summary report to guide the user for further data analyses.

First do no harm: Moving beyond universal pre-procedural testing for COVID-19

Pre-procedural testing for SARS-CoV-2 was introduced early in the pandemic in an effort to protect healthcare workers, direct appropriate use of personal protective equipment (PPE), and improve patient outcomes. In light of our appreciation for the efficacy of PPE and the nuances associated with interpretation of polymerase chain reaction (PCR) testing for SARS-CoV-2, particularly as community transmission decreases, we call for a re-evaluation of universal pre-procedural testing. We propose a transition to a patient-centered approach, focusing on testing patients whose outcomes would be improved by a delayed procedure in the event of a positive test and a greater reliance on appropriate PPE rather than pre-procedural test results. We recommend that a community infection rate threshold be set at which point pre-procedural testing is discontinued, understanding that there is an inflection point at which testing downsides outweigh the benefits.

To be raised up or kicked out? Insights for the recycler in closed-loop supply chain with the regulation of government

In order to improve the recovery rate of waste products and maximize the social welfare, this paper investigates the problem of government setting a recovery rate threshold for the recycler in the closed-loop supply chain (CLSC) with the information asymmetry. By establishing the government incentive regulation model, the government can disclose the true recovery cost of the recycler and guide the recycler to make an reasonable effort. In this study, our model obtains the best recovery rate threshold for the recycler from the perspective of maximizing social welfare. Then, we conduct some sensitivity analyses and explore the impacts of related factors on the strategies-making of government and supply chain players. The results of the study indicates that the recovery rate threshold set not only depends on the operation efficiency of the recycler, it also affected by the consumers behavior and the production efficiency of manufacturer. The government should not pursue a high recovery rate blindly, more attention should be paid to control the cost of effort made by the recycler. With the increasing of the negative utility for the recycler to make effort, the government will improve the recovery threshold, otherwise, the threshold will decrease. The results facilitate scientific incentive mechanism development, and provide a reference for promoting CLSC operations.

Effects of Al Particle Size on the Impact Energy Release of Al-Rich PTFE/Al Composites under Different Strain Rates

Polytetrafluoroethylene (PTFE)/Al reactive material with different aluminum particle sizes were prepared by molding and sintering, and the effect of aluminum particle size on the impact behavior of PTFE/Al reactive material with a mass ratio of 50:50 was investigated. The results show that aluminum particle size has significant effects on the shock-reduced reaction diffusion, reaction speed, and degree of reaction of the PTFE/Al reactive material. At a moderate strain rate, the reaction delay of PTFE/Al increased, and the reaction duration and degree decreased, with the increase of aluminum particle size. Under the strong impact of explosive loading, aluminum particle size has little effect on the reaction delay, which maintains at about 1.5 μs–2.5 μs, but the reaction durability and degree of reaction of PTFE/Al decrease with increasing aluminum particle size. There is also a strain rate threshold for the shock-induced reaction of PTFE/Al reactive material, which is closely related to aluminum particle size. The shock-induced reaction occurs when the strain rate threshold is exceeded.

Impact of Exchange Rate Threshold Level on Stock Market Performance-Evidence from Ghana

Exchange rate plays a vital role in an economy and the purpose of this study is to investigate the impact of exchange rate threshold level on the capital market performance. The study employed a Threshold Autoregressive model introduced by Tong (1978) and Hansen (1996). The study used secondary quarter-time series data for thirty-years from 1990 to 2019. The capital market performance was measured by the value of shares traded; market turnover; market capitalization and all-shares index. However, the results revealed the following estimated threshold level of exchange rate for each performance indicator: 7.94%; 25.33%; 25.33% and 7.80% respectively. In all, the threshold level of the exchange rate estimated was 8 and 25 per cent. The findings suggest that low exchange rate is performance-enhancing. In addition, the exchange rate above the threshold level is detrimental to the capital market performance. The findings of this investigation might be helpful to the government of Ghana and policymakers as they settle on an exchange rate target to adopt to avoid the detrimental effects of high exchange rate while obtaining the growth benefits of the low exchange rate. It has indicated that the exchange rate impacts the economy more than inflation in the Sub Saharan Africa but, not much works in the subject area in Sub Saharan Africa. Therefore, I recommend that more threshold studies have to be carried out on the exchange rate in the other sectors of the economy to ascertain its impact on the economy.

Modeling of the COVID-19 pandemic in the limit of no acquired immunity

We propose the SEIRS compartmental epidemiology model aimed at modeling the COVID-19 pandemy dynamics. The limit case of no acquired immunity (neither natural nor via vaccination) is considered mimicking the situation (i) when no effective vaccine being developed or available yet, and (ii) the virus strongly mutates causing massive reinfections. Therefore, the only means of suppressing the virus spread are via quarantine measures and effective identification and isolation of infected individuals. We found both the disease-free and the endemic fixed points and examined their stability. The basic reproduction ratio is obtained and its dependence on the parameters of the model is discussed. We found the presence of the contact rate threshold beyond which the disease-free fixed point cannot be reached. Using the numeric solution, the approximate analytic solution of the model, characterized by rescaled contact rate, is obtained. Several possible "quarantine on"/"quarantine off" scenarios are considered and the one combined with flexible adjustment of the identification and isolation rates is found to be the most effective in bringing the second and consequent waves down. The study can be interpreted as a reference point for the case when the natural or acquired immunity, as well as vaccination, are taken into account. It will be a topic of a separate study.

A rate threshold mechanism regulates MAPK stress signaling and survival

Cells are exposed to changes in extracellular stimulus concentration that vary as a function of rate. However, how cells integrate information conveyed from stimulation rate along with concentration remains poorly understood. Here, we examined how varying the rate of stress application alters budding yeast mitogen-activated protein kinase (MAPK) signaling and cell behavior at the single-cell level. We show that signaling depends on a rate threshold that operates in conjunction with stimulus concentration to determine the timing of MAPK signaling during rate-varying stimulus treatments. We also discovered that the stimulation rate threshold and stimulation rate-dependent cell survival are sensitive to changes in the expression levels of the Ptp2 phosphatase, but not of another phosphatase that similarly regulates osmostress signaling during switch-like treatments. Our results demonstrate that stimulation rate is a regulated determinant of cell behavior and provide a paradigm to guide the dissection of major stimulation rate dependent mechanisms in other systems.

Exploiting Memory Resilience for Emerging Technologies: An Energy-Aware Resilience Exemplar for STT-RAM Memories

Due to the consistent pressing quest of larger on-chip memories and caches of multicore and manycore architectures, Spin Transfer Torque Magnetic RAM (STT-MRAM or STT-RAM) has been proposed as a promising technology to replace classical SRAMs in near-future devices. Main advantages of STT-RAMs are a considerably higher transistor density and a negligible leakage power compared with SRAM technology. However, the drawback of this technology is the high probability of errors occurring especially in write operations. Such errors are asymmetric and transition-dependent, where 0 → 1 is the most critical one, and is high subjected to the amount and current (voltage) supplied to the memory during the write operation. As a consequence, STT-RAMs present an intrinsic trade-off between energy consumption vs. reliability that needs to be properly tuned w.r.t. the currently running application and its reliability requirement. This chapter proposes FlexRel, an energy-aware reliability improvement architectural scheme for STT-RAM cache memories. FlexRel considers a memory architecture provided with Error Correction Codes (ECCs) and a custom current regulator for the various cache ways and conducts a trade-off between reliability and energy consumption. FlexRel cache controller dynamically profiles the number of 0 → 1 transitions of each individual bit write operation in a cache block and based on that selects the most-suitable cache way and current level to guarantee the necessary error rate threshold (in terms of occurred write errors) while minimizing the energy consumption. We experimentally evaluated the efficiency of FlexRel against the most efficient uniform protection scheme from reliability, energy, area, and performance perspectives. Experimental simulations performed by using gem5 has demonstrated that while FlexRel satisfies the given error rate threshold, it delivers up to 13.2% energy saving. From the area footprint perspective, FlexRel delivers up to 7.9% cache ways’ area saving. Furthermore, the performance overhead of the FlexRel algorithm which changes the traffic patterns of the cache ways during the executions is 1.7%, on average.