Clinical effectiveness for interventions in humans can only be speculated from animal studies.
Abstract Social media platforms have an increasing influence in biomedical and other disciplines of science and public health. While Twitter has been a popular platform for scientific communication, changes in ownership have led some users to consider migrating to other platforms such as Mastodon. We aimed to investigate how many top-cited scientists are active on these social media platforms, the magnitude of the migration to Mastodon, and correlates of Twitter presence. A random sample of 900 authors was examined among those who are at the top-2% of impact based on a previously validated composite citation indicator using Scopus data. Searches for their personal Twitter accounts were performed in early December 2022, and re-evaluations were performed at 2 weeks, 4 weeks, and 2 months (February 6, 2023). 262/900 (29.1%) of highly-cited scholars had Twitter accounts, and only 9/800 (1%) had Mastodon accounts. Female gender, North American and Australia locations, younger publication age, and clinical medicine or social science expertise correlated with higher percentages of Twitter use. The vast majority of highly-cited author users of Twitter had few followers and tweets. Only 6 had more than 10,000 followers and none had more than 100,000. One limitation of our study is that it is possible that some accounts, especially with Mastodon, could not be detected. However, the study suggests that Twitter remains the preferred social media platform for highly-cited authors, and Mastodon has not yet challenged Twitter’s dominance. Moreover, most highly-cited scientists with Twitter accounts have limited presence in this medium.
High-level hardware generators have significantly increased the productivity of design engineers. They use software engineering constructs to reduce the repetition required to express complex designs and enable more composability. However, these benefits are undermined by a lack of debugging infrastructure, requiring hardware designers to debug generated, usually incomprehensible, RTL code. This paper describes a framework that connects modern software source-level debugging frameworks to RTL created from hardware generators. Our working prototype offers an Integrated Development Environment (IDE) experience for generators such as RocketChip (Chisel), allowing designers to set breakpoints in complex source code, relate RTL simulation state back to source-level variables, and do forward and backward debugging, with almost no simulation overhead (less than 5%).
Recently there has been a surge of interest in low-power devices and design techniques. While many papers have been published describing power-saving techniques for use in digital systems, trade-offs between the methods are rarely discussed. We address this issue by using an energy-delay metric to compare many of the proposed techniques. Using this metric also provides insight into some of the basic trade-offs in low-power design. The next section describes the energy-loss mechanisms that are present in CMOS circuits, which provides the parameters that must be changed to lower the power dissipation. With these factors in mind, the rest of the paper reviews the energy saving techniques that have been proposed. These proposals fall into one of three main strategies: trade speed for power, do not waste power, and find a lower power problem.
ABSTRACT Objective To assess the evidence on the presence of antibodies cross-reactive with SARS-CoV-2 antigens in pre-pandemic samples from African populations. Methods We performed a systematic review and meta-analysis of studies evaluating pre-pandemic African samples using pre-set assay-specific thresholds for SARS-CoV-2 seropositivity. Results 26 articles with 156 datasets were eligible, including 3,437 positives among 29,923 measurements (11.5%) with large between-dataset heterogeneity. Positivity was similar for anti-N (14%) and anti-S antibodies (11%), higher for anti-S1 (23%) and lower for anti-RBD antibodies (7%). Positivity was similar, on average, for IgM and IgG. Positivity was seen prominently in countries where malaria transmission occurs throughout and in datasets enriched in malaria cases (14%, 95% CI, 12-15% versus 2%, 95% CI 1-2% in other datasets). Substantial SARS-CoV-2 reactivity was seen in high malaria burden with or without high dengue burden (14% and 12%, respectively), and not without high malaria burden (2% and 0%, respectively). Lower SARS-CoV-2 cross-reactivity was seen in countries and cohorts of high HIV seroprevalence. More sparse individual-level data showed associations of higher SARS-CoV-2 cross-reactivity with Plasmodium parasitemia and lower SARS-CoV-2 cross-reactivity with HIV seropositivity. Conclusions Pre-pandemic samples from Africa show high levels of anti-SARS-CoV-2 seropositivity. Levels of cross-reactivity tracks especially with malaria prevalence.
In this paper, a global clock network that incor- porates standing waves and coupled oscillators to distribute a high-frequency clock signal with low skew and low jitter is described. The key design issues involved in generating standing waves on a chip are discussed, including minimizing wire loss within an available technology. A standing-wave oscillator, which is a distributed oscillator that sustains ideal standing waves on lossy wires, is introduced. A clock grid architecture comprised of coupled standing-wave oscillators and differential low-swing clock buffers is presented, along with a compact circuit model for networks of oscillators. The measured results for a prototyped standing-wave clock grid operating at 10 GHz and fabricated in a 0.18- m 6M CMOS logic process are presented. A technique is proposed for on-chip skew measurements with subpicosecond precision.
Petitions have a long history of being used for political, social, ethical and injustice issues; however, it is unclear how/whether they should be implemented in scientific argumentation. Recently, an extremely influential commentary published in Nature (Amrhein et al, 2019) calling for the abandonment of ‘statistical significance’ was signed by 854 scientists. We surveyed signatories and observed substantial heterogeneity in respondents’ perceptions of the petition process, motivations for signing and views on aspects of abandoning statistical significance. The top-cited signatories were strongly concentrated in a few scientific fields. In a random sample of 100 signatories, 62 published at least one paper in 2018 using statistical inference and most of them had used the phrase ‘statistical significance’. When scientists sign petitions, they may have variable views on important aspects and it is useful to understand this diversity.
In this paper, we propose an architecture for FPGA emulation of mixed-signal systems that achieves high accuracy at a high throughput. We represent the analog output of a block as a superposition of step responses to changes in its analog input, and the output is evaluated only when needed by the digital subsystem. Our architecture is therefore intended for digitally-driven systems; that is, those in which the inputs of analog dynamical blocks change only on digital clock edges. We implemented a high-speed link transceiver design using the proposed architecture on a Xilinx FPGA. This design demonstrates how our approach breaks the link between simulation rate and time resolution that is characteristic of prior approaches. The emulator is flexible, allowing for the real-time adjustment of analog dynamics, clock jitter, and various design parameters. We demonstrate that our architecture achieves 1% accuracy while running 3 orders of magnitude faster than a comparable high-performance CPU simulation.
