138 research outputs found

    Specifying and Verifying Concurrent Algorithms with Histories and Subjectivity

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    We present a lightweight approach to Hoare-style specifications for fine-grained concurrency, based on a notion of time-stamped histories that abstractly capture atomic changes in the program state. Our key observation is that histories form a partial commutative monoid, a structure fundamental for representation of concurrent resources. This insight provides us with a unifying mechanism that allows us to treat histories just like heaps in separation logic. For example, both are subject to the same assertion logic and inference rules (e.g., the frame rule). Moreover, the notion of ownership transfer, which usually applies to heaps, has an equivalent in histories. It can be used to formally represent helping---an important design pattern for concurrent algorithms whereby one thread can execute code on behalf of another. Specifications in terms of histories naturally abstract granularity, in the sense that sophisticated fine-grained algorithms can be given the same specifications as their simplified coarse-grained counterparts, making them equally convenient for client-side reasoning. We illustrate our approach on a number of examples and validate all of them in Coq.Comment: 17 page

    Faster linearizability checking via PP-compositionality

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    Linearizability is a well-established consistency and correctness criterion for concurrent data types. An important feature of linearizability is Herlihy and Wing's locality principle, which says that a concurrent system is linearizable if and only if all of its constituent parts (so-called objects) are linearizable. This paper presents PP-compositionality, which generalizes the idea behind the locality principle to operations on the same concurrent data type. We implement PP-compositionality in a novel linearizability checker. Our experiments with over nine implementations of concurrent sets, including Intel's TBB library, show that our linearizability checker is one order of magnitude faster and/or more space efficient than the state-of-the-art algorithm.Comment: 15 pages, 2 figure

    Disease avoidance motives trade-off against social motives, especially mate-seeking, to predict social distancing: evidence from the COVID-19 pandemic

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    A range of studies have sought to understand why people's compliance with social distancing varied during the COVID-19 pandemic. Recent theory suggests that pathogen avoidance behavior is based not only on perceived risk but on a trade-off between the perceived costs of pathogen exposure and the perceived benefits of social contact. We hypothesized that compliance with social distancing may therefore be explained by a trade-off between pathogen avoidance and various social motives such as mate-seeking. Two studies conducted during the COVID-19 pandemic showed that social distancing was positively associated with disease avoidance motives but negatively associated with social motives, especially mating motives. These associations remained after controlling for predictors identified by previous research, including risk perception and personality. Findings indicate that people who are more interested in seeking new romantic partners (e.g., young men) may be less inclined to socially distance and be more at risk of pathogen transmission

    Fundamental social motives measured across forty-two cultures in two waves

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    How does psychology vary across human societies? The fundamental social motives framework adopts an evolutionary approach to capture the broad range of human social goals within a taxonomy of ancestrally recurring threats and opportunities. These motives—self-protection, disease avoidance, affiliation, status, mate acquisition, mate retention, and kin care—are high in fitness relevance and everyday salience, yet understudied cross-culturally. Here, we gathered data on these motives in 41 countries (N=15,885) in two cross-sectional waves, including 19 countries (N=11,095) for which data were gathered in both waves. Wave 1 was collected from 2016 through mid-2019 (32 countries, N=9353; 3537 male, 5574 female; Mage=24.58, SD=8.07). Wave 2 was collected from May through October 2020, during the COVID-19 pandemic (N=6532; 2194 male, 4165 female; Mage=28.82, SD=11.49). These data can be used to assess differences and similarities in people’s fundamental social motives both across and within cultures, at different time points, and in relation to other commonly studied cultural indicators and outcomes

    Challenges and opportunities for increasing patient involvement in heart failure self-care programs and self-care in the post–hospital discharge period

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    Background: People living with heart failure (HF) are particularly vulnerable after hospital discharge. An alliance between patient authors, clinicians, industry, and co-developers of HF programs can represent an effective way to address the unique concerns and obstacles people living with HF face during this period. The aim of this narrative review article is to discuss challenges and opportunities of this approach, with the goal of improving participation and clinical outcomes of people living with HF. Methods: This article was co-authored by people living with HF, heart transplant recipients, patient advocacy representatives, cardiologists with expertise in HF care, and industry representatives specializing in patient engagement and cardiovascular medicine, and reviews opportunities and challenges for people living with HF in the post–hospital discharge period to be more integrally involved in their care. A literature search was conducted, and the authors collaborated through two virtual roundtables and via email to develop the content for this review article. Results: Numerous transitional-care programs exist to ease the transition from the hospital to the home and to provide needed education and support for people living with HF, to avoid rehospitalizations and other adverse outcomes. However, many programs have limitations and do not integrally involve patients in the design and co-development of the intervention. There are thus opportunities for improvement. This can enable patients to better care for themselves with less of the worry and fear that typically accompany the transition from the hospital. We discuss the importance of including people living with HF in the development of such programs and offer suggestions for strategies that can help achieve these goals. An underlying theme of the literature reviewed is that education and engagement of people living with HF after hospitalization are critical. However, while clinical trial evidence on existing approaches to transitions in HF care indicates numerous benefits, such approaches also have limitations. Conclusion: Numerous challenges continue to affect people living with HF in the post–hospital discharge period. Strategies that involve patients are needed, and should be encouraged, to optimally address these challenges

    Antiarrhythmic and antioxidant activity of novel pyrrolidin-2-one derivatives with adrenolytic properties

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    A series of novel pyrrolidin-2-one derivatives (17 compounds) with adrenolytic properties was evaluated for antiarrhythmic, electrocardiographic and antioxidant activity. Some of them displayed antiarrhythmic activity in barium chloride-induced arrhythmia and in the rat coronary artery ligation-reperfusion model, and slightly decreased the heart rate, prolonged P–Q, Q–T intervals and QRS complex. Among them, compound EP-40 (1-[2-hydroxy-3-[4-[(2-hydroxyphenyl)piperazin-1-yl]propyl]pyrrolidin-2-one showed excellent antiarrhythmic activity. This compound had significantly antioxidant effect, too. The present results suggest that the antiarrhythmic effect of compound EP-40 is related to their adrenolytic and antioxidant properties. A biological activity prediction using the PASS software shows that compound EP-35 and EP-40 can be characterized by antiischemic activity; whereas, compound EP-68, EP-70, EP-71 could be good tachycardia agents

    Fundamental social motives measured across forty-two cultures in two waves

    Get PDF
    How does psychology vary across human societies? The fundamental social motives framework adopts an evolutionary approach to capture the broad range of human social goals within a taxonomy of ancestrally recurring threats and opportunities. These motives—self-protection, disease avoidance, affiliation, status, mate acquisition, mate retention, and kin care—are high in fitness relevance and everyday salience, yet understudied cross-culturally. Here, we gathered data on these motives in 42 countries (N = 15,915) in two cross-sectional waves, including 19 countries (N = 10,907) for which datawere gathered in both waves. Wave 1 was collected from mid-2016 through late 2019 (32 countries, N = 8,998; 3,302 male, 5,585 female; Mage = 24.43, SD = 7.91). Wave 2 was collected from April through November 2020, during the COVID-19 pandemic (29 countries, N = 6,917; 2,249 male, 4,218 female; Mage = 28.59, SD = 11.31). These data can be used to assess differences and similarities in people’s fundamental social motives both across and within cultures, at different time points, and in relation to other commonly studied cultural indicators and outcomes
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