bluuebunny/crossref_metadata_2025 huggingface dataset:
Supplemental Material: Evidence for large Holocene earthquakes along the Yangsan fault in the SE Korean Peninsula revealed in three-dimensional paleoseismic trenches
Authors: Naik Sambit Prasanajit , Kim Young-Seog , al. et
Published: June 2024

Figure S1: Shows the dextral movement over the last 50-60 Ma, measuring the long-term slip rate of the Yangsan fault.; Figure S2: Abanico plot displaying the dose rate distribution of the OSL samples.; Figures S3 and S4: Comparison between Quartz OSL and C14 age from the 3D trench.; Figures S5 and S6: OxCal model for different scenarios of MRE and Penultimate event timing based on OSL and C14 age.; Figure S7: Scaling relationship between surface rupture and displacement for strike-slip fault earthquakes from intraplate regions, including the present study.
Pros and cons of internal limiting membrane peeling during epiretinal membrane surgery: a randomised clinical trial with microperimetry (PEELING)
Authors: Ducloyer Jean-Baptiste , Eude Yannick , Volteau Christelle , Lebreton Olivier , Bonissent Alexandre , Fossum Paul , Tadayoni Ramin , Creuzot-Garcher Catherine P , Le Mer Yannick , Perol Julien , Fortin June , Jobert Alexandra , Billaud Fanny , Ivan Catherine , Poinas Alexandra , Weber Michel
Published: June 2024

Background

After idiopathic epiretinal membrane (iERM) removal, it is unclear whether the internal limiting membrane (ILM) should be removed. The objective was to assess if active ILM peeling after iERM removal could induce microscotomas.

Methods

The PEELING study is a national randomised clinical trial. When no spontaneous ILM peeling occurred, patients were randomised either to the ILM peeling or no ILM peeling group. Groups were compared at the month 1 (M1), M6 and M12 visits in terms of microperimetry, best-corrected visual acuity (BCVA) and optical coherence tomography findings. The primary outcome was the difference in microscotoma number between baseline and M6.

Results

213 patients were included, 101 experienced spontaneous ILM peeling and 100 were randomised to the ILM peeling (n=51) or no ILM peeling group (n=49). The difference in microscotoma number between both groups was significant at M1 (3.9 more microscotomas in ILM peeling group, (0.8;7.0) p=0.0155) but not at M6 (2.1 more microscotomas in ILM peeling group (−0.5;4.7) p=0.1155). Only in the no ILM peeling group, the number of microscotomas significantly decreased and the mean retinal sensitivity significantly improved. The ERM recurred in nine patients in the no ILM peeling group (19.6%) versus zero in the ILM peeling group (p=0.0008): two of them underwent revision surgery. There was no difference in mean BCVA and microperimetry between patients experiencing or not a recurrence at M12.

Conclusion

Spontaneous ILM peeling is very common. Active ILM peeling prevents anatomical ERM recurrence but may induce retinal impairments and delay visual recovery.

Trial Registration

NCT02146144
.
Codesigned standardised referral form: simplifying the complexity
Authors: Laing Scott , Jarmain Sarah , Elliott Jacobi , Dang Janet , Gylfadottir Vala , Wierts Kayla , Nair Vineet
Published: June 2024

Background

Referring providers are often critiqued for writing poor-quality referrals. This study characterised clinical referral guidelines and forms to understand which data consultant providers require. These data were then used to codesign an evidence-based, high-quality referral form.

Methods

This study used both observational and quality improvement approaches. Canadian referral guidelines were reviewed and summarised. Referral data fields from 150 randomly selected Ontario referral forms were categorised and counted. The referral guideline summary and referral data were then used by referring providers, consultant providers and administrators to codesign a referral form.

Results

Referral guidelines recommended 42 types of referral data be included in referrals. Referral data were categorised as patient demographics, provider demographics, reason for referral, clinical information and administrative information. The percentage of referral guidelines recommending inclusion of each type of referral data varied from 8% to 77%. Ontario referral forms requested 264 different types of referral data. Digital referral forms requested more referral data types than paper-based referral forms (55.0±10.6 vs 30.5±8.1; 95% CI p<0.01). A codesigned referral form was created across two sessions with 29 and 21 participants in each.

Discussion

Referral guidelines lack consistency and specificity, which makes writing high-quality referrals challenging. Digital referral forms tend to request more referral data than paper-based referrals, which creates administrative burdens for referring and consultant providers. We created the first codesigned referral form with referring providers, consultant providers and administrators. We recommend clinical adoption of this form to improve referral quality and minimise administrative burdens.
Screening for adverse social conditions in child healthcare settings: protocol for a systematic review
Authors: Schwenker Rosemarie , Alayli Adrienne , Rasch Lena , Ballmeyer Christian , Maguire Jonathon L , Cohen-Silver Justine , De Bock Freia
Published: June 2024

Introduction

Adverse social conditions affect children’s development and health outcomes from preconception throughout their life course. Early identification of adverse conditions is essential for early support of children and their families. Healthcare contacts with children provide a unique opportunity to screen for adverse social conditions and to take preventive action to identify and address emerging, potentially harmful or accumulating social problems. The aim of our study is to identify and describe available screening tools in outpatient and inpatient healthcare settings that capture social conditions that may affect children’s development, health or well-being.

Methods and analysis

We will conduct a systematic review and will report the results following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. A systematic search of three databases (PubMed (Ovid), PsycInfo (EBSCOhost) and Web of Science Core Collection (Clarivate)) for English-language and German-language articles from 2014 to date will be conducted. We will include peer-reviewed articles that develop, describe, test or use an instrument to screen children for multiple social conditions in paediatric clinics or other outpatient or inpatient child healthcare settings. Key study characteristics and information on screening tools will be extracted and presented in structured tables to summarise the available evidence. We will assess the methodological quality of the instruments with the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist.

Ethics and dissemination

Ethical approval is not required for this study as we will not be collecting any personal data. Dissemination will consist of publications, presentations, and other knowledge translation activities.
Identifying the needs of people with long COVID: a qualitative study in the UK
Authors: Miller Amy , Song Ning , Sivan Manoj , Chowdhury Rumana , Burke Melanie Rose
Published: June 2024

Objectives

To identify the needs of people with long COVID (LC) in the UK.

Design

Qualitative study using the Framework Analysis to analyse focus group discussions.

Participants

25 adults with LC aged 19–76 years including 17 men and 8 women. Average disease duration was 80.1 weeks.

Setting

Eight focus groups were conducted in April 2023 online and in-person at the University of Leeds (UoL), UK. Recruitment routes included advertisement via Leeds Community Healthcare services, the English National Opera Breathe Programme and within the UoL.

Results

Three key themes/needs were identified. (Theme 1) Support systems including community groups, disability benefits, clinical services and employment support should be accessible and tailored to the needs of people with LC. (Theme 2) Research should investigate the physiology of symptoms, new clinical tests and treatment interventions to improve clinical understanding of the condition and symptom management. (Theme 3) Societal awareness should be promoted via local and national initiatives to educate the public about the condition and reduce stigma.

Conclusions

Participants experienced varied and individual challenges to daily life due to LC. There is a need for government acknowledgement of LC as a disability to ensure people with LC have access to disability support and legal protection. Policy development should be patient-driven and acknowledge the individual needs of people with LC in order to improve their quality of life.
Association of social support before ICU admission with postdischarge mental health symptoms in ICU patients: a single-centre prospective cohort study in Japan
Authors: Yoshino Yasuyo , Unoki Takeshi , Hata Kimiko , Ito Kiyoe
Published: June 2024

Objectives

Mental health problems after discharge from the intensive care unit (ICU) interfere with physical recovery and seriously affect daily life. Social support has been suggested to be associated with mental health but has not been sufficiently characterised. This study aimed to evaluate the association of social support before ICU admission with mental health after ICU discharge.

Design

Prospective cohort study.

Setting

Medical–surgical ICU of a hospital in Japan.

Participants

Patients admitted to the ICU for more than 48 hours were surveyed on social support prior to ICU admission, and 3 months after discharge from the ICU, mental health questionnaires were mailed to the patient.

Primary outcome measures

Post-traumatic stress disorder (PTSD)-related symptoms were measured using the Impact of Event Scale-Revised, and anxiety and depressive symptoms were measured using the Hospital Anxiety and Depression Scale.

Results

A total of 153 patients were enrolled; the prevalence of PTSD-related symptoms, anxiety and depressive symptoms 3 months after discharge from the ICU was 11.3%, 14.0% and 24.6%, respectively. Multivariate analysis using linear regression models adjusted for age, sex and years of education for PTSD-related symptoms, anxiety and depressive symptoms revealed that social support (β=−0.018, 95% CI: −0.029 to 0.006, p=0.002) and female sex (β=0.268, 95% CI: 0.005 to 0.531, p=0.046) were independent factors associated with the severity of depressive symptoms. In addition, sex differences were observed in the association between depressive symptoms and social support (p for interaction=0.056).

Conclusions

Higher social support before ICU admission was not associated with PTSD symptoms after ICU discharge, although it may be associated with a lower prevalence depressive symptoms after ICU discharge. Therefore, it is important to provide necessary social support when needed.
Assessing the feasibility and acceptability of a diabetes-specific nurse-led multicomponent smoking cessation intervention in diabetes education: study protocol for an open-label pragmatic randomised controlled trial
Authors: Grech Joseph , Norman Ian , Azzopardi Catherine , Grixti Moira , Sammut Roberta
Published: June 2024

Introduction

Smoking cessation is an essential, but often overlooked aspect of diabetes management. Despite the need for tailored smoking cessation support for individuals with diabetes, evidence of effective interventions for this cohort is limited. Additionally, individuals with diabetes do not easily adopt such interventions, resulting in low uptake and abstinence rates. This protocol describes a study that aims to assess the feasibility and acceptability of a unique smoking cessation intervention, based on the best evidence, theory and the needs of individuals with diabetes, among patients and service providers, the diabetes nurse educators.

Methods and analysis

This is an open-label pragmatic randomised controlled trial. Between 80 and 100 individuals with type 1 or type 2 diabetes who smoke will be recruited from the diabetes outpatients at the main acute public hospital in Malta, starting in August 2023. Participants will be randomly assigned (1:1 ratio) to the intervention or control arm for 12 weeks. The experimental intervention will consist of three to four smoking cessation behavioural support sessions based on the 5As (Ask, Advise, Assess, Assist and Arrange) algorithm, and a 6-week supply of nicotine replacement therapy. The control intervention will consist of an active referral to the Maltese National Health Service’s one-to-one smoking cessation support service, which is based on motivational interviewing. The primary feasibility and acceptability outcomes include the recruitment and participation rates, resources used, problems identified by the nurses, the nurses’ perceived challenges and facilitators to implementation and the nurses’ and patients’ acceptability of the study intervention. Data analyses will be descriptive, with quantitative feasibility and acceptability outcomes reported with 95% confidence intervals.

Ethics and dissemination

Ethical clearance was obtained from the Faculty of Health Sciences Research Ethics Committee, University of Malta. The study results will be disseminated through conference presentations and a publication in a peer-reviewed journal.

Trial registration number

NCT05920096.
Improving quality of care by standardising patient data collection in electronic medical records in an oncology department in Spain
Authors: Alonso-Jáudenes Curbera Guillermo , Gómez-Randulfe Rodríguez Martín Igor , Alonso de Castro Beatriz , Silva Díaz Sofía , Parajó Vázquez Iria , Gratal Paula , López López Rafael , García Campelo Rosario
Published: June 2024

Background

Evaluation of quality of care in oncology is key in ensuring patients receive adequate treatment. American Society of Clinical Oncology’s (ASCO) Quality Oncology Practice Initiative (QOPI) Certification Program (QCP) is an international initiative that evaluates quality of care in outpatient oncology practices.

Methods

We retrospectively reviewed free-text electronic medical records from patients with breast cancer (BR), colorectal cancer (CRC) or non-small cell lung cancer (NSCLC). In a baseline measurement, high scores were obtained for the nine disease-specific measures of QCP Track (2021 version had 26 measures); thus, they were not further analysed. We evaluated two sets of measures: the remaining 17 QCP Track measures, as well as these plus other 17 measures selected by us (combined measures). Review of data from 58 patients (26 BR; 18 CRC; 14 NSCLC) seen in June 2021 revealed low overall quality scores (OQS)—below ASCO’s 75% threshold—for QCP Track measures (46%) and combined measures (58%). We developed a plan to improve OQS and monitored the impact of the intervention by abstracting data at subsequent time points.

Results

We evaluated potential causes for the low OQS and developed a plan to improve it over time by educating oncologists at our hospital on the importance of improving collection of measures and highlighting the goal of applying for QOPI certification. We conducted seven plan–do–study–act cycles and evaluated the scores at seven subsequent data abstraction time points from November 2021 to December 2022, reviewing 404 patients (199 BR; 114 CRC; 91 NSCLC). All measures were improved. Four months after the intervention, OQS surpassed the quality threshold and was maintained for 10 months until the end of the study (range, 78–87% for QCP Track measures; 78–86% for combined measures).

Conclusions

We developed an easy-to-implement intervention that achieved a fast improvement in OQS, enabling our Medical Oncology Department to aim for QOPI certification.
Factors associated with proximal femoral fractures in older adults during hospital stay: a cross-sectional study
Authors: Moriwaki Mutsuko , Takae Asuka , Toba Mikayo , Sasaki Miki , Ogata Yasuko , Obayashi Satoshi , Kakehashi Masayuki , Fushimi Kiyohide
Published: June 2024

Background

Proximal femoral fractures in older adults affect prognosis, quality of life and medical expenses. Therefore, identifying patients with an elevated risk for proximal femoral fractures and implementing preventive measures to mitigate their occurrence are crucial.

Objective

This study aimed to develop an accurate in-hospital fracture prediction model that considers patients’ daily conditions and medical procedure status. Additionally, it investigated the changes in their conditions associated with fractures during hospital stays.

Design

A retrospective observational study.

Setting(s)

Acute care hospitals in Japan.

Participants

Participants were 8 514 551 patients from 1321 medical facilities who had been discharged between April 2018 and March 2021 with hip and proximal femoral fractures.

Methods

Logistic regression analysis determined the association between patients’ changes in their ability to transfer at admission and the day before fracture, and proximal femoral fracture during hospital stays.

Results

Patients were classified into fracture and non-fracture groups. The mean ages were 77.4 (SD: 7.7) and 82.6 (SD: 7.8), and the percentages of women were 42.7% and 65.3% in the non-fracture and fracture groups (p<0.01), respectively. Model 4 showed that even if a patient required partial assistance with transfer on the day before the fracture, the fracture risk increased in each category of change in ability to transfer in the following order: ‘declined’, ‘improved’ and ‘no change’.

Conclusions

Patients showing improved ability to transfer during their hospitalisation are at a higher risk for fractures. Monitoring patients’ daily conditions and tracking changes can help prevent fractures during their hospital stays.
High accuracy model for HBsAg loss based on longitudinal trajectories of serum qHBsAg throughout long-term antiviral therapy
Authors: Fan Rong , Zhao Siru , Niu Junqi , Ma Hong , Xie Qing , Yang Song , Xie Jianping , Dou Xiaoguang , Shang Jia , Rao Huiying , Xia Qi , Liu Yali , Yang Yongfeng , Gao Hongbo , Sun Aimin , Liang Xieer , Yin Xueru , Jiang Yongfang , Yu Yanyan , Sun Jian , Naoumov Nikolai V , Hou Jinlin
Published: June 2024

Objective

Hepatitis B surface antigen (HBsAg) loss is the optimal outcome for patients with chronic hepatitis B (CHB) but this rarely occurs with currently approved therapies. We aimed to develop and validate a prognostic model for HBsAg loss on treatment using longitudinal data from a large, prospectively followed, nationwide cohort.

Design

CHB patients receiving nucleos(t)ide analogues as antiviral treatment were enrolled from 50 centres in China. Quantitative HBsAg (qHBsAg) testing was prospectively performed biannually per protocol. Longitudinal discriminant analysis algorithm was used to estimate the incidence of HBsAg loss, by integrating clinical data of each patient collected during follow-up.

Results

In total, 6792 CHB patients who had initiated antiviral treatment 41.3 (IQR 7.6–107.6) months before enrolment and had median qHBsAg 2.9 (IQR 2.3–3.3) log10IU/mL at entry were analysed. With a median follow-up of 65.6 (IQR 51.5–84.7) months, the 5-year cumulative incidence of HBsAg loss was 2.4%. A prediction model integrating all qHBsAg values of each patient during follow-up, designated GOLDEN model, was developed and validated. The AUCs of GOLDEN model were 0.981 (95% CI 0.974 to 0.987) and 0.979 (95% CI 0.974 to 0.983) in the training and external validation sets, respectively, and were significantly better than those of a single qHBsAg measurement. GOLDEN model identified 8.5%–10.4% of patients with a high probability of HBsAg loss (5-year cumulative incidence: 17.0%–29.1%) and was able to exclude 89.6%–91.5% of patients whose incidence of HBsAg loss is 0. Moreover, the GOLDEN model consistently showed excellent performance among various subgroups.

Conclusion

The novel GOLDEN model, based on longitudinal qHBsAg data, accurately predicts HBsAg clearance, provides reliable estimates of functional hepatitis B virus (HBV) cure and may have the potential to stratify different subsets of patients for novel anti-HBV therapies.
Universal Credit receipt among working-age patients who are accessing specialist mental health services: results from a novel data linkage study
Authors: Stevelink Sharon A M , Bakolis Ioannis , Dorrington Sarah , Downs Johnny , Leal Ray , Madan Ira , Phillips Ava , Geiger Ben , Hotopf Matthew , Fear Nicola T
Published: June 2024

Background

In 2013, Universal Credit (UC) was introduced by the UK Government. Understanding of how UC provision is allocated among people with mental disorders, and its intersection with protected characteristics is limited. This study aimed to explore (1) how UC receipt, including UC conditionality regime, varied among users of specialist mental health services between 2013 and 2019 and (2) associations between sociodemographic and diagnostic patient characteristics and UC receipt.

Methods

Working-age individuals who had accessed specialist mental health services were included if they had their mental health record data successfully linked with administrative benefits data. Associations between sociodemographic, diagnostic patient characteristics and UC receipt were explored using logistic regression models.

Results

Of the 143 715 patients, 26.9% had received UC between 2013 and 2019. Four in five patients were allocated to the searching for work conditionality regime during their time on UC. Females were less likely to have received UC (adjusted OR (AOR) 0.87, 95% CI 0.85 to 0.89) than males, and UC receipt decreased with age. Black patients (AOR 1.39, 95% CI 1.34 to 1.44) and patients from mixed and multiple ethnic backgrounds (AOR 1.27, 95% CI 1.18 to 1.38) had a higher likelihood of UC receipt than White patients. UC receipt was lower among patients diagnosed with severe mental illness compared with other psychiatric diagnoses (AOR 0.74, 95% CI 0.71 to 0.77).

Conclusion

One in four specialist mental health service users had received UC and a large majority were subject to conditionality. The temporality of UC conditionality and mental health service presentation needs further exploration.
Kindness in healthcare leadership and management: an evaluation and analysis of the concept
Authors: Dyar Rebecca , Mattick Karen , Griffiths Andrew
Published: June 2024

Background

Healthcare leadership and management impacts every patient journey and every staff experience. Good leadership results in positive outcomes. Kindness is an understudied and underused leadership strategy. The research questions addressed in this study are the following: (1) Does kindness in healthcare leadership and management currently meet the criteria of a mature concept?; (2) Using concept analysis methodology, can we develop our understanding of kindness within this context?

Methods

A systematic search of the peer-reviewed literature was conducted to inform a concept evaluation, followed by a concept analysis. Search terms consisted of ‘leader*’ or ‘manage*’ and ‘kindness’; databases searched comprised MEDLINE, HMIC, SPP, APA PsycInfo and CINAHL. Data extraction and thematic analysis of the data were performed manually according to concept analysis principles.

Results

The 10 papers included from the search suggested that within healthcare leadership and management, kindness is an ‘emerging’ rather than a ‘mature’ concept. Concept analysis demonstrated a cluster of recurring attributes, allowing a theoretical definition to be put forth.

Conclusions

Despite being a commonly used lay term, kindness in the context of healthcare leadership and management is not yet a mature concept. Work developing this concept is needed to validate the proposed theoretical definition. Observational studies and systematic review of the grey literature are recommended.
Diaphragm wall lateral movement in deep excavations in Bangkok clays: impacts and influencing factors
Authors: Boonyarak Thayanan , Aung Aye Yadana , Kamchoom Viroon , Aye Zaw Zaw
Published: June 2024

Deep excavation in Bangkok clay layers involving diaphragm walls can cause ground movement, potentially affecting nearby structures. Understanding the magnitude and profile of this movement is crucial for assessing its impact on adjacent buildings. This study examines factors influencing the lateral displacement of rigid diaphragm walls in Bangkok’s deep excavations, including construction methods, excavation duration, depth ratios, soft clay depth, and system stiffness. The research data were collected from 230 dataset of lateral movement in diaphragm walls with a thickness ranging from 0.60 to 1.50 m. These walls had toe depths between 14 and 65 m, across various excavation depths ( He) from 6 to 35 m. Maximum lateral wall displacements ranged from 0.10% He to 0.27% He for the top-down method, and from 0.20% He to 0.50% He for the bottom-up method. If the system stiffness is sufficient, variations in wall thickness and construction method have minimal impact on wall deflection. However, with the bottom-up method and 1.0 m thick walls, long excavation times can lead to displacements up to 0.60% He. This is mainly due to consolidation and creep in the clay beneath the area where the base slab construction is delayed.
Unruh effect using Doppler shift method in DSR framework
Authors: Rajagopal Vishnu
Published: June 2024

We study the Unruh effect in doubly special relativity (DSR) framework by generalising the Doppler-shift method to DSR. For both the scalar and Dirac particles, we observe a deviation in the power spectrum of Unruh radiation from the standard Bose–Einstein and Fermi–Dirac distributions, respectively, due to the presence of the frame independent length scale of DSR. We further show that this deviation results in the modification of Unruh temperature which then depends non-linearly on the proper acceleration in DSR.
Quasinormal modes in noncommutative Schwarzschild black holes: a spectral analysis
Authors: Batic Davide , Dutykh Denys
Published: June 2024

We present a comprehensive analysis of quasinormal modes (QNMs) for noncommutative geometry-inspired Schwarzschild black holes, encompassing both non-extreme and extreme cases. By employing a spectral method, we calculate the QNMs in the context of scalar, electromagnetic, and gravitational perturbations. Our findings not only challenge previous claims in the literature regarding the instability of these black holes but also reveal remarkable stability for both non-extreme and extreme Schwarzschild black holes under various perturbations.
Continuous variable entanglement between propagating optical modes using optomechanics
Authors: Gopinath Greeshma , Li Yong , Davuluri Sankar
Published: June 2024

In this study, a method for entangling two spatially separated output laser fields from an optomechanical cavity is proposed. In the existing standard methods, entanglement is created by driving the two-mode squeezing part of the linearized optomechanical interaction;, however our method generates entanglement using the quantum back-action nullifying meter technique. As a result, entanglement can be generated outside the blue sideband frequency in both resolved and unresolved sideband regimes. We further show that the system is stable in the entire region where the Duan criterion for inseparability is fulfilled. The effect of thermal noise on the generated entanglement is examined. Finally, we compare this technique with standard methods for entanglement generation using optomechanics.
Modular Hardware Design of Pipelined Circuits with Hazards
Authors: Jang Minseong , Rhee Jungin , Lee Woojin , Zhao Shuangshuang , Kang Jeehoon
Published: June 2024

Modular design is critical in reducing hardware designer's cognitive load and development cost.

However, it is challenging to modularize high-performance pipelined circuits with structural, data, and control hazards because their resolution---stalling, and bypassing, and discard-and-restarting---introduce cross-stage dependencies.

The dependencies could potentially mandate monolithic control logic and create combinational loops, hindering modular design.

An effective method to modularize pipelined circuits is valid-ready interfaces, but they apply to a relatively simple form of pipelined circuits only with structural hazards.

We propose hazard interfaces, a generalization of valid-ready interfaces that can modularize pipelined circuits not only with structural but also with data and control hazards.

The key idea is enveloping the cross-stage dependencies within interfaces.

We also design combinators for hazard interfaces in the style of map-reduce that facilitate decomposition of control logic.

We implement a compiler (to synthesizable Verilog) for a prototype language supporting hazard interfaces and combinators, and design a sound and efficient type checker that proves the absence of combinational loops.

With case studies on 5-stage RISC-V CPU core and 100 Gbps Ethernet NIC, we demonstrate that hazard interfaces indeed facilitate modular design while incurring no noticeable cost in performance, power, and area over reference designs in Chisel and Verilog.
Recursive Program Synthesis using Paramorphisms
Authors: Hong Qiantan , Aiken Alex
Published: June 2024

We show that synthesizing recursive functional programs using a class of primitive recursive combinators is both simpler and solves more benchmarks from the literature than previously proposed approaches. Our method synthesizes paramorphisms, a class of programs that includes the most common recursive programming patterns on algebraic data types. The crux of our approach is to split the synthesis problem into two parts: a multi-hole template that fixes the recursive structure, and a search for non-recursive program fragments to fill the template holes.
Concurrent Immediate Reference Counting
Authors: Jung Jaehwang , Kim Jeonghyeon , Parkinson Matthew J. , Kang Jeehoon
Published: June 2024

Memory management for optimistic concurrency in unmanaged programming languages is challenging. Safe memory reclamation (SMR) algorithms help address this, but they are difficult to use correctly. Automatic reference counting provides a simpler interface, but it has been less efficient than SMR algorithms. Recently, there has been a push to apply the optimizations used in garbage collectors for managed languages to elide reference count updates from local references. Notably, Fast Reference Counter, OrcGC, and Concurrent Deferred Reference Counting use SMR algorithms to protect local references by deferring decrements or reclamation. While they show a significant performance improvement, their use of deferral may result in growing memory usage due to slow reclamation of linked structures, and suboptimal performance in update-heavy workloads.

We present
Concurrent Immediate Reference Counting
(CIRC), a new combination of SMR algorithms with reference counting. CIRC employs deferral like other modern methods, but it avoids their problems with novel algorithms for (1) immediately reclaiming linked structures recursively by tracking the reachability of each object, and (2) applying decrements immediately and deferring only the reclamation. Our experiments show that CIRC’s memory usage does not grow over time and is only slightly higher than the underlying SMR. Moreover, CIRC further narrows the performance gap between the underlying SMR, positioning it as a promising solution to safe automatic memory management for highly concurrent data structures in unmanaged languages.
A Proof Recipe for Linearizability in Relaxed Memory Separation Logic
Authors: Park Sunho , Kim Jaewoo , Mulder Ike , Jung Jaehwang , Lee Janggun , Krebbers Robbert , Kang Jeehoon
Published: June 2024

Linearizability is the de facto standard for correctness of concurrent objects—it essentially says that all the object’s operations behave as if they were atomic. There have been a number of recent advances in developing increasingly strong linearizability specifications for relaxed memory consistency (RMC), but scalable
proof methods
for these specifications do not exist due to the challenges arising from out-of-order executions (requiring event reordering) and selected synchronization (requiring tracking of view transfers).

We propose a proof recipe for the
linearizable history specifications
by Dang et al. in the Iris-based iRC11 concurrent separation logic in Coq. Key to our proof recipe is the notion of
object modification order (OMO)
, which generalizes the modification order of the C11 memory model to an object-local setting. Using OMO we minimize the conditions that need to be proved for event reordering. To enable proof reuse for concurrent libraries that are built on top of others, OMO provides the novel notion of a
commit-with relation
that connects the linearization points of the lower and upper libraries. Using our recipe, we verify the linearizability of the Michael–Scott queue, the elimination stack, and Folly’s MPMC queue in RMC for the first time; and verify stronger specifications of a spinlock and atomic reference counting in RMC than prior work.
Diffy: Data-Driven Bug Finding for Configurations
Authors: Kakarla Siva Kesava Reddy , Yan Francis Y. , Beckett Ryan
Published: June 2024

Configuration errors remain a major cause of system failures and service outages. One promising approach to identify configuration errors automatically is to learn common usage patterns (and anti-patterns) using data-driven methods. However, existing data-driven learning approaches analyze only simple configurations (e.g., those with no hierarchical structure), identify only simple types of issues (e.g., type errors), or require extensive domain-specific tuning. In this paper, we present Diffy, the first push-button configuration analyzer that detects likely bugs in structured configurations. From example configurations, Diffy learns a common template, with "holes" that capture their variation. It then applies unsupervised learning to identify anomalous template parameters as likely bugs. We evaluate Diffy on a large cloud provider's wide-area network, an operational 5G network testbed, and MySQL configurations, demonstrating its versatility, performance, and accuracy. During Diffy's development, it caught and prevented a bug in a configuration timer value that had previously caused an outage for the cloud provider.
Boosting Compiler Testing by Injecting Real-World Code
Authors: Li Shaohua , Theodoridis Theodoros , Su Zhendong
Published: June 2024

We introduce a novel approach for testing optimizing compilers with code from real-world applications. The main idea is to construct well-formed programs by fusing multiple code snippets from various real-world projects. The key insight is backed by the fact that the large volume of real-world code exercises rich syntactical and semantic language features, which current engineering-intensive approaches like random program generators are hard to fully support.
To construct well-formed programs from real-world code, our approach works by (1) extracting real-world code at the granularity of function, (2) injecting function calls into seed programs, and (3) leveraging dynamic execution information to maintain the semantics and build complex data dependencies between injected functions and the seed program. With this idea, our approach complements the existing generators by boosting their expressiveness via fusing real-world code in a semantics-preserving way.

We implement our idea in a tool, Creal, to test C compilers. In a nine-month testing period, we have reported 132 bugs to GCC and LLVM, two of the most popular and well-tested C compilers.
At the time of writing, 121 of them have been confirmed as unknown bugs, and 101 of them have been fixed. Most of these bugs were miscompilations, and many were recognized as long-latent and critical.
Our evaluation results evidently demonstrate the significant advantage of using real-world code to stress-test compilers. We believe this idea will benefit the general compiler testing direction and will be directly applicable to other compilers.
SMT Theory Arbitrage: Approximating Unbounded Constraints using Bounded Theories
Authors: Mikek Benjamin , Zhang Qirun
Published: June 2024

SMT solvers are foundational tools for reasoning about constraints in practical problems both within and outside program analysis. Faster SMT solving improves the performance of practical tools and expands the set of tractable problems. Existing approaches to improving solver performance either focus on general algorithms applied below the level of individual theories, or focus on optimizations within a single theory. Unbounded constraints in which the number of possible variable values is infinite, such as real numbers and integers, pose a particularly difficult challenge for solvers. Bounded constraints in which the set of possible values is finite, such as bitvectors and floating-point numbers, on the other hand, are decidable and have been the subject of extensive performance improvement efforts.

This paper introduces a theory arbitrage: we transform unbounded constraints, which are often expensive to solve, into bounded constraints, which are typically cheaper to solve. By converting unbounded problems into bounded ones, theory arbitrage takes advantage of better performance on bounded constraints and unlocks optimization techniques that only apply to bounded theories. The transformation is achieved by harnessing a novel abstract interpretation strategy to infer bounds. The bounded transformed constraint is then an underapproximation of the semantics of the unbounded original. We realize our method for the theories of integers and real numbers with a practical tool (STAUB). Our evaluation demonstrates that theory arbitrage alone can speed up individual constraints by orders of magnitude and achieve up to a 1.4× speedup on average across nonlinear integer benchmarks. Furthermore, it enables the use of the recent compiler optimization-based technique SLOT for unbounded SMT theories, unlocking a further speedup of up to 3×. Finally, we incorporate STAUB into a practical termination proving tool and observe an overall 9% improvement in performance.
A Verified Compiler for a Functional Tensor Language
Authors: Liu Amanda , Bernstein Gilbert , Chlipala Adam , Ragan-Kelley Jonathan
Published: June 2024

Producing efficient array code is crucial in high-performance domains like image processing and machine learning. It requires the ability to control factors like compute intensity and locality by reordering computations into different stages and granularities with respect to where they are stored. However, traditional pure, functional tensor languages struggle to do so. In a previous publication, we introduced ATL as a pure, functional tensor language capable of systematically decoupling compute and storage order via a set of high-level combinators known as reshape operators. Reshape operators are a unique functional-programming construct since they manipulate storage location in the generated code by modifying the indices that appear on the left-hand sides of storage expressions. We present a formal correctness proof for an implementation of the compilation algorithm, marking the first verification of a lowering algorithm targeting imperative loop nests from a source functional language that enables separate control of compute and storage ordering. One of the core difficulties of this proof required properly formulating the complex invariants to ensure that these storage-index remappings were well-formed. Notably, this exercise revealed a soundness bug in the original published compilation algorithm regarding the truncation reshape operators. Our fix is a new type system that captures safety conditions that were previously implicit and enables us to prove compiler correctness for well-typed source programs. We evaluate this type system and compiler implementation on a range of common programs and optimizations, including but not limited to those previously studied to demonstrate performance comparable to established compilers like Halide.
Associated Effects: Flexible Abstractions for Effectful Programming
Authors: Lutze Matthew , Madsen Magnus
Published: June 2024

We present associated effects, a programming language feature that enables type
classes to abstract over the effects of their function signatures, allowing each
type class instance to specify its concrete effects.

Associated effects significantly increase the flexibility and expressive power
of a programming language that combines a type and effect system with type
classes. In particular, associated effects allow us to
(i) abstract over total and partial functions, where partial functions may throw exceptions,
(ii) abstract over immutable data structures and mutable data structures that have heap effects, and
(iii) implement adaptors that combine type classes with algebraic effects.

We implement associated effects as an extension of the Flix programming language
and refactor the Flix Standard Library to use associated effects, significantly
increasing its flexibility and expressive power. Specifically, we add associated
effects to 11 type classes, which enables us to add
28 new type class instances.
The T-Complexity Costs of Error Correction for Control Flow in Quantum Computation
Authors: Yuan Charles , Carbin Michael
Published: June 2024

Numerous quantum algorithms require the use of quantum error correction to overcome the intrinsic unreliability of physical qubits. However, quantum error correction imposes a unique performance bottleneck, known as
T
-complexity, that can make an implementation of an algorithm as a quantum program run more slowly than on idealized hardware. In this work, we identify that programming abstractions for control flow, such as the quantum if-statement, can introduce polynomial increases in the
T
-complexity of a program. If not mitigated, this slowdown can diminish the computational advantage of a quantum algorithm.

To enable reasoning about the costs of control flow, we present a cost model that a developer can use to accurately analyze the
T
-complexity of a program under quantum error correction and pinpoint the sources of slowdown. To enable the mitigation of these costs, we present a set of program-level optimizations that a developer can use to rewrite a program to reduce its
T
-complexity, predict the
T
-complexity of the optimized program using the cost model, and then compile it to an efficient circuit via a straightforward strategy.

We implement the program-level optimizations in Spire, an extension of the Tower quantum compiler. Using a set of 11 benchmark programs that use control flow, we empirically show that the cost model is accurate, and that Spire’s optimizations recover programs that are asymptotically efficient, meaning their runtime
T
-complexity under error correction is equal to their time complexity on idealized hardware.

Our results show that optimizing a program before it is compiled to a circuit can yield better results than compiling the program to an inefficient circuit and then invoking a quantum circuit optimizer found in prior work. For our benchmarks, only 2 of 8 tested quantum circuit optimizers recover circuits with asymptotically efficient
T
-complexity. Compared to these 2 optimizers, Spire uses 54×–2400× less compile time.
VESTA: Power Modeling with Language Runtime Events
Authors: Raskind Joseph , Babakol Timur , Mahmoud Khaled , Liu Yu David
Published: June 2024

Power modeling is an essential building block for computer systems in support of energy optimization, energy profiling, and energy-aware application development. We introduce VESTA, a novel approach to modeling the power consumption of applications with one key insight: language runtime events are often correlated with a sustained level of power consumption. When compared with the established approach of power modeling based on hardware performance counters (HPCs), VESTA has the benefit of solely requiring application-scoped information and enabling a higher level of explainability, while achieving comparable or even higher precision. Through experiments performed on 37 real-world applications on the Java Virtual Machine (JVM), we find the power model built by VESTA is capable of predicting energy consumption with a mean absolute percentage error of 1.56%, while the monitoring of language runtime events incurs small performance and energy overhead.
Quantitative Robustness for Vulnerability Assessment
Authors: Girol Guillaume , Lacombe Guilhem , Bardin Sébastien
Published: June 2024

Most software analysis techniques focus on bug reachability. However, this approach is not ideal for security evaluation as it does not take into account the difficulty of triggering said bugs. The recently introduced notion of robust reachability tackles this issue by distinguishing between bugs that can be reached independently from uncontrolled inputs, from those that cannot. Yet, this qualitative notion is too strong in practice as it cannot distinguish mostly replicable bugs from truly unrealistic ones. In this work we propose a more flexible quantitative version of robust reachability together with a dedicated form of symbolic execution, in order to automatically measure the difficulty of triggering bugs. This quantitative robust symbolic execution (QRSE) relies on a variant of model counting, called functional E-MAJSAT, which allows to account for the asymmetry between attacker-controlled and uncontrolled variables. While this specific model counting problem has been studied in AI research fields such as Bayesian networks, knowledge representation and probabilistic planning, its use within the context of formal verification presents a new set of challenges. We show the applicability of our solutions through security-oriented case studies, including real-world vulnerabilities such as CVE-2019-20839 from libvncserver.
GenSQL: A Probabilistic Programming System for Querying Generative Models of Database Tables
Authors: Huot Mathieu , Ghavami Matin , Lew Alexander K. , Schaechtle Ulrich , Freer Cameron E. , Shelby Zane , Rinard Martin C. , Saad Feras A. , Mansinghka Vikash K.
Published: June 2024

This article presents GenSQL, a probabilistic programming system for querying probabilistic generative models of database tables. By augmenting SQL with only a few key primitives for querying probabilistic models, GenSQL enables complex Bayesian inference workflows to be concisely implemented. GenSQL’s query planner rests on a unified programmatic interface for interacting with probabilistic models of tabular data, which makes it possible to use models written in a variety of probabilistic programming languages that are tailored to specific workflows. Probabilistic models may be automatically learned via probabilistic program synthesis, hand-designed, or a combination of both. GenSQL is formalized using a novel type system and denotational semantics, which together enable us to establish proofs that precisely characterize its soundness guarantees. We evaluate our system on two case real-world studies—an anomaly detection in clinical trials and conditional synthetic data generation for a virtual wet lab—and show that GenSQL more accurately captures the complexity of the data as compared to common baselines. We also show that the declarative syntax in GenSQL is more concise and less error-prone as compared to several alternatives. Finally, GenSQL delivers a 1.7-6.8x speedup compared to its closest competitor on a representative benchmark set and runs in comparable time to hand-written code, in part due to its reusable optimizations and code specialization.