bluuebunny/crossref_metadata_2025 huggingface dataset:
Observing time effect of SSRIs on suicide risk and suicide-related behaviour: a network meta-analysis protocol
Authors: Chen Qing-Hua , Li Yu-Ling , Hu Yi-Ru , Liang Wan-Yuan , Zhang Bin
Published: December 2021

Introduction

Suicide is a serious problem worldwide and 90% cases are associated with pre-existing or underlying mental illness. As a common treatment for depressive symptoms that suicidal people may receive, selective serotonin reuptake inhibitors (SSRIs) have been linked to a possible increase in suicide rates. Studies focusing on SSRIs and suicide have produced inconsistent results, suggesting that use of SSRIs decreases, increases, has no effect on suicide rates, or that the effect of SSRIs on suicide is age-dependent. This protocol of network meta-analysis aims to precisely evaluate the time effects of SSRIs by observing weekly changes of suicidality in the first 2 months of the treatment, and consequently, to explore whether the effect of the SSRIs on suicide varies depending on the stages of the treatment; if so, we will identify the turning point.

Methods and analysis

We will search in the following databases: PubMed, Web of science, China National Knowledge Infrastructure and Wanfang Data, from dates of inception to 9 July 2021, with language restricted to English and Chinese. Studies focusing on the time effect of SSRIs on suicide will be retrieved. Then, the study selection process will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline, and the quality assessment will be conducted with Cochrane Collaboration’s tool. Two researchers will work independently on data extraction using a standardised data extraction spreadsheet. Any disagreement between two researchers will be discussed and determined by a third researcher.

Ethics and dissemination

This work does not require ethics approval as it will be based on published studies. This review will be published in peer-reviewed journals.

PROSPERO registration number

CRD42021244779.
Length of stay in health facilities after childbirth and associated maternal and neonatal factors in Ethiopia: a cross-sectional study from a national survey
Authors: Biru Yemisrach Belete , Lemelem Getasew Assefa , Solomon Nahom
Published: December 2021

Objective

This study aimed to assess the length of stay in health facilities after childbirth and associated maternal and neonatal factors in Ethiopia.

Design

A cross-sectional study.

Setting

Ethiopia.

Participants

2260 mothers who participated in the 2016 Ethiopian Demographic and Health Survey were included in the study.

Outcome

Length of stay in health facilities after childbirth was the outcome variable of the study.

Result

In Ethiopia, the mean duration of postpartum stay for mothers in health facilities was 21.96 (19.97–23.94) hours. Nine hundred and sixty-eight (34.80%) women remained in health institutions for ≥24 hours after delivery. Gestational age, birth weight and mode of delivery were significantly associated with length of stay. Gestational age was found to be inversely associated with length of stay. Mothers who had a vaginal delivery were 8.89% (adjusted HR (AHR) 8.89, 95% CI (4.28 to 18.46), p<0.001) more likely to discharge earlier from health facilities after delivery, compared with those who had a caesarian section. Women with larger size neonates during birth were 19% (AHR=0.81, 95% CI (0.67 to 0.96), p=0.019) more likely to stay longer in health facilities than women with average size neonates. Women with a smaller size neonate during birth were 16% (AHR=0.84, 95% CI (0.70 to 0.99), p=0.040) more likely to stay longer at a health facility, compared with those with an average size neonate.

Conclusion

A small percentage of Ethiopian mothers stayed in health facilities for 24 hours or more after delivery. Encouraging mothers to stay in health facilities for the recommended period after childbirth can play a significant role in reducing maternal and neonatal deaths.
Nurse-run preanaesthesia assessment clinics: an initiative towards improving the quality of perioperative care at the ambulatory care centre
Authors: Arun Neethu , Al-Jaham Khalid Mohammed Ahmed , Alhebail Saadiya Ahmad , Hassan Mohammad Jamal Abdallah , Bakhit Refa Hanish , Paulose Johncy , Marcus Marco AE , Ramachandran Balakrishnan , Lance Marcus D
Published: December 2021

Introduction

Nurse-run preanaesthesia assessment is well established in ambulatory surgery. However, in the Middle East the implementation of such a service is new and needed careful preparation. Aim of this audit is to assess the feasibility and the quality of preoperative assessments by the specially trained nurses, patient and nurse satisfaction and overall perioperative quality of recovery.

Methods

The nurses were selected and trained first in an accredited programme. Then an implementation period of 3 month was used for them to gain experience. Hereafter, we performed a four-step audit on the quality of preassessment, the patient’s satisfaction, the quality of recovery and adverse events if any. Finally, we also monitored the nurse’s satisfaction of their new advanced role.

Results

The quality of preanaesthesia assessment was high as with 95% compliance to the accepted standards. In the patient satisfaction survey, all 152 patients were either highly satisfied or satisfied with the nurse-run service. The nurses were also highly satisfied and felt that they were either highly or moderately valued. All the patients who were operated at the ambulatory care services were followed up postoperatively by telephone calls which revealed that most of them were highly satisfied. No major or minor adverse events occurred.

Conclusion

Our specially trained nurses perform preoperative assessments on high standard without adverse events, while patient and staff satisfaction is very high. Future projects will focus on reducing the rate of cancellation of surgeries, investigating the cost-effectiveness of this approach as well as training the specialised nurses for paediatric preoperative anaesthesia assessments. This model of care could induce further nurse-run models of care in the Middle East.
Role of 3D printing technology in paediatric teaching and training: a systematic review
Authors: Asif Ashar , Lee Elgin , Caputo Massimo , Biglino Giovanni , Shearn Andrew Ian Underwood
Published: December 2021

Background

In the UK, undergraduate paediatric training is brief, resulting in trainees with a lower paediatric knowledge base compared with other aspects of medicine. With congenital conditions being successfully treated at childhood, adult clinicians encounter and will need to understand these complex pathologies. Patient-specific 3D printed (3DP) models have been used in clinical training, especially for rarer, complex conditions. We perform a systematic review to evaluate the evidence base in using 3DP models to train paediatricians, surgeons, medical students and nurses.

Methods

Online databases PubMed, Web of Science and Embase were searched between January 2010 and April 2020 using search terms relevant to “paediatrics”, “education”, “training” and “3D printing”. Participants were medical students, postgraduate trainees or clinical staff. Comparative studies (patient-specific 3DP models vs traditional teaching methods) and non-comparative studies were included. Outcomes gauged objective and subjective measures: test scores, time taken to complete tasks, self-reported confidence and personal preferences on 3DP models. If reported, the cost of and time taken to produce the models were noted.

Results

From 587 results, 15 studies fit the criteria of the review protocol, with 5/15 being randomised controlled studies and 10/15 focussing on cardiovascular conditions. Participants using 3DP models demonstrated improved test scores and faster times to complete procedures and identify anatomical landmarks compared with traditional teaching methods (2D diagrams, lectures, videos and supervised clinical events). User feedback was positive, reporting greater user self-confidence in understanding concepts with users wishing for integrated use of 3DP in regular teaching. Four studies reported the costs and times of production, which varied depending on model complexity and printer. 3DP models were cheaper than ‘off-the-shelf’ models available on the market and had the benefit of using real-world pathologies. These mostly non-randomised and single-centred studies did not address bias or report long-term or clinically translatable outcomes.

Conclusions

3DP models were associated with greater user satisfaction and good short-term educational outcomes, with low-quality evidence. Multicentred, randomised studies with long-term follow-up and clinically assessed outcomes are needed to fully assess their benefits in this setting.

PROSPERO registration number

CRD42020179656.
Building on sand: digital technologies for care coordination and advance care planning
Authors: Allsop Matthew John , Chumbley Karen , Birtwistle Jacqueline , Bennett Michael I , Pocock Lucy
Published: December 2021

Approaches using digital technologies to support advance care planning (ACP) and care coordination are being used in palliative and end of life care. While providing opportunities to facilitate increases in the completeness, sharing and availability of care plans, the evidence base underpinning their use remains limited. We outline an approach that continues to be developed in England; Electronic Palliative Care Coordination Systems (EPaCCS). Stages governing their optimal use are outlined alongside unanswered questions with relevance across technology-mediated approaches to ACP. Research has a critical role in determining if technology-mediated approaches to ACP, such as EPaCCS, could be useful tools to support the delivery of care for patients with chronic and progressive illnesses.
Bullying in UK cardiology: a systemic problem requiring systemic solutions
Authors: Camm Christian Fielder , Joshi Abhishek , Moore Abigail , Sinclair Hannah C , Westwood Mark , Greenwood John Pierre , Calver Alison , Ray Simon , Allen Christopher
Published: December 2021

Objectives

Bullying of trainee doctors has been shown to be associated with detrimental outcomes for both doctors and patients. However, there is limited evidence regarding the level of bullying of trainees within medical specialties.

Methods

An annual survey of UK cardiology trainees was conducted through the British Junior Cardiologists’ Association between 2017 and 2020 and asked questions about experiencing and witnessing bullying, and exposure to inappropriate language/behaviour in cardiology departments. Fisher’s exact tests and univariable logistic regression models were used to describe associations between trainee characteristics, and reports of bullying and inappropriate language/behaviour.

Results

Of 1358 trainees, bullying was reported by 152 (11%). Women had 55% higher odds of reporting being bullied (OR: 1.55 95% CI (1.08 to 2.21)). Non-UK medical school graduates were substantially more likely to be bullied (European Economic Area (EEA) OR: 2.22 (1.31 to 3.76), non-EEA/UK OR: 3.16 (2.13 to 4.68)) compared with those graduating from UK-based medical schools. Women were more likely than men to report sexist language (14% vs 4%, p<0.001). Non-UK medical school graduates were more likely to experience racist language (UK 1.5%, EEA 6%, other locations 7%, p=0.006). One-third of trainees (33%) reported at least one inappropriate behaviour with 8% reporting being shouted at or targeted with spontaneous anger. Consultants in cardiology (82%) and other specialties (70%) were most commonly implicated by those reporting bullying.

Discussion

Bullying and inappropriate language are commonly experienced by cardiology trainees and disproportionately affect women and those who attended non-UK medical schools. Consultants both in cardiology and other specialties are the most commonly reported perpetrators.
Uncoupled biological and chronological aging of neutrophils in cancer promotes tumor progression
Authors: Mittmann Laura A , Haring Florian , Schaubächer Johanna B , Hennel Roman , Smiljanov Bojan , Zuchtriegel Gabriele , Canis Martin , Gires Olivier , Krombach Fritz , Holdt Lesca , Brandau Sven , Vogl Thomas , Lauber Kirsten , Uhl Bernd , Reichel Christoph A
Published: December 2021

Background

Beyond their fundamental role in homeostasis and host defense, neutrophilic granulocytes (neutrophils) are increasingly recognized to contribute to the pathogenesis of malignant tumors. Recently, aging of mature neutrophils in the systemic circulation has been identified to be critical for these immune cells to properly unfold their homeostatic and anti-infectious functional properties. The role of neutrophil aging in cancer remains largely obscure.

Methods

Employing advanced in vivo microscopy techniques in different animal models of cancer as well as utilizing pulse-labeling and cell transfer approaches, various ex vivo/in vitro assays, and human data, we sought to define the functional relevance of neutrophil aging in cancer.

Results

Here, we show that signals released during early tumor growth accelerate biological aging of circulating neutrophils, hence uncoupling biological from chronological aging of these immune cells. This facilitates the accumulation of highly reactive neutrophils in malignant lesions and endows them with potent protumorigenic functions, thus promoting tumor progression. Counteracting uncoupled biological aging of circulating neutrophils by blocking the chemokine receptor CXCR2 effectively suppressed tumor growth.

Conclusions

Our data uncover a self-sustaining mechanism of malignant neoplasms in fostering protumorigenic phenotypic and functional changes in circulating neutrophils. Interference with this aberrant process might therefore provide a novel, already pharmacologically targetable strategy for cancer immunotherapy.
Risk factors for changes in carotid intima media thickness and plaque over 5 years in women with systemic lupus erythematosus
Authors: Lertratanakul Apinya , Sun Julia , Wu Peggy W , Lee Jungwha , Dyer Alan , Pearce William , McPherson David , Sutton-Tyrrell Kim , Thompson Trina , Barinas-Mitchell Emma , Ramsey-Goldman Rosalind
Published: December 2021

Objective

To investigate the occurrence of and risk factors for progression of carotid intima media thickness (IMT) and plaque in women with and without SLE.

Methods

A cohort of 149 women with SLE and 126 controls participated in SOLVABLE (Study of Lupus Vascular and Bone Long-term Endpoints). Demographics, cardiovascular and SLE factors, and laboratory assessments were collected at baseline. Carotid IMT and plaque were measured using B-mode ultrasound at baseline and at 5-year follow-up. Regression models were used to identify predictors of progression in carotid IMT and plaque; multivariate models were adjusted for age, hypertension and total cholesterol to high-density lipoprotein ratio.

Results

The mean±SD follow-up time was 5.35±0.60 years in cases and 5.62±0.66 years in controls. The mean IMT change per year was 0.008±0.015 mm in cases and 0.005±0.019 mm in controls (p=0.24). At follow-up, 31.5% of cases and 15% of controls had plaque progression, with a relative risk for plaque progression of 2.09 (95% CI 1.30 to 3.37). In SLE cases, higher fasting glucose and lower fibrinogen were associated with IMT progression after adjustment. Larger waist circumference and non-use of hydroxychloroquine were associated with plaque progression after adjustment.

Conclusion

Potential modifiable risk factors for carotid IMT and plaque progression in women with SLE were identified, suggesting that monitoring of glucose and waist circumference and use of hydroxychloroquine may be beneficial.
Health-related quality of life after thrombectomy in young-onset versus older stroke patients: a multicenter analysis
Authors: Deb-Chatterji Milani , Pinho João , Flottmann Fabian , Meyer Lukas , Broocks Gabriel , Brekenfeld Caspar , Reich Arno , Fiehler Jens , Gerloff Christian , Thomalla Goetz
Published: December 2021

Background

Information is lacking on self-reported health-related quality of life (HRQoL) as a complementary outcome measure in addition to the modified Rankin scale (mRS) in young patients with ischemic stroke after endovascular thrombectomy (EVT) compared with older patients.

Methods

Data on consecutive patients with stroke who underwent thrombectomy (June 2015–2019) from a multicenter prospective registry (German Stroke Registry) were analyzed. HRQoL was measured by the European QoL-5 dimension questionnaire utility index (EQ-5D-I; higher values indicate better HRQoL) 3 months after stroke in patients aged ≤55 and >55 years. Multivariate regression analyses identified predictors of better HRQoL.

Results

Of 4561 included patients, 526 (11.5%) were ≤55 years old. Young-onset patients had a better outcome assessed by mRS (mRS 0–2: 64.3% vs 31.8%, p<0.001) and EQ-5D-I (mean 0.639 vs 0.342, p<0.001). Young survivors after EVT had fewer complaints in the EQ-5D domains mobility (p<0.001), self-care (p<0.001), usual activities (p<0.001) and pain/discomfort (p=0.008), whereas no difference was observed in anxiety/depression (p=0.819). Adjusted regression analysis for 90-day mRS showed no difference in HRQoL between the two subgroups of patients. Lower age, National Institutes of Health Stroke Scale score and pre-stroke mRS, a higher Alberta Stroke Program Early CT Score, concomitant intravenous thrombolysis therapy and successful recanalization were associated with better HRQoL in both patient subgroups.

Conclusions

Young-onset stroke patients have a better HRQoL after EVT than older patients. Their higher HRQoL is mainly explained by less physical disability assessed by mRS. Depressive symptoms should be actively assessed and targeted in rehabilitation therapies of young-onset stroke patients to improve quality of life after stroke.
Recent cannabis use and nightly sleep duration in adults: a population analysis of the NHANES from 2005 to 2018
Authors: Diep Calvin , Tian Chenchen , Vachhani Kathak , Won Christine , Wijeysundera Duminda N , Clarke Hance , Singh Mandeep , Ladha Karim S
Published: December 2021

Background

While popularly consumed for its perceived benefits as a sleeping aid, the impact of cannabis on sleep-wake regulation in clinical studies is inconclusive. The purpose of this study was to determine the relationship between cannabis use and nightly sleep duration in a nationally representative dataset.

Methods

A cross-sectional analysis of adults was undertaken using the National Health and Nutrition Examination Survey data from 2005 to 2018. Respondents were dichotomized as recent users or non-users if they had used or not used cannabis in the past 30 days, respectively. The primary outcome was nightly sleep duration, categorized as short (<6 hours), optimal (6–9 hours), and long (>9 hours). Multinomial logistic regression was used to adjust for sociodemographic and health-related covariates, and survey sample weights were used in modeling.

Results

From a sample representing approximately 146 million adults in the USA, 14.5% reported recent cannabis use. In an adjusted analysis, recent users were more likely than non-users to report both short sleep (OR 1.34, 95% CI 1.12 to 1.59, p<0.001) and long sleep (OR 1.56, 95% CI 1.25 to 1.96, p<0.001). Heavy users (≥20 of the past 30 days) were even more likely to be at the extremes of nightly sleep duration.

Discussion

Recent cannabis use was associated with the extremes of nightly sleep duration in a nationally representative sample of adults, with suggestions of a dose–response relationship. Our findings highlight the need to further characterize the sleep health of regular cannabis users in the population.
Centrifuge tests on axially loaded tapered piles with different cross-sections under compressive and tensile loading
Authors: Shabanpour Alireza , Ghazavi Mahmoud
Published: December 2021

The compressive behavior of tapered piles, particularly those with circular cross-sections, has been investigated during the last few decades. However, the tensile behavior of such piles has been rarely studied in the literature. In this paper, 12 static axial tests, comprising six compressive and six tensile tests, were performed on instrumented piles with uniform and tapered cross-sections using a geotechnical centrifuge. Three of the piles had correspondingly circular, square, and X-shaped uniform cross-sections along their length, while the other three were non-uniform (tapered), all of which had the same length and volume. The results are presented in three main forms: variation of load versus pile head displacement, distribution of axial force along the pile length, and distribution of unit shaft resistance along the pile length. Behavior of the tapered piles is compared with that of the uniform cross-section piles. The results confirm the superiority of tapered piles over uniform cross-section piles in terms of load-bearing capacity and construction costs under both tensile and compressive loading.
Post-fire peatland vegetation recovery: a case study in open rich fens of the Canadian boreal forest
Authors: Guêné-Nanchen Mélina , LeBlanc Marie-Claire , Rochefort Line
Published: December 2021

Fire plays a major role in the structuring and functioning of boreal ecosystems. As peatlands are important components of boreal forests, the impact of fire upon these wetter ecosystems is increasingly studied, but with the focus on treed peatlands and Sphagnum-dominated bogs so far. Important fires occurring more frequently in the past decade in southern Northwest Territories (Canada) provide the opportunity to assess early post-fire vegetation regeneration in open rich fens (one, two, and five years post-fire) and to better understand early recovery succession. We aimed to (i) evaluate whether and how open rich fens are affected by fire, and (ii) describe short-term vegetation regeneration for both bryophytes and vascular species. A shift was observed between pioneer bryophytes and brown mosses between the second and fifth year post-fire. Vascular plants, especially slow-growing species and the ones reproducing mainly by seeds, recovered partially. The first bryophyte species recovering were pioneer species adapted to colonize burned environments such as Marchantia polymorpha L. or Ceratodon purpureus (Hedw.) Brid. For vascular plant species, the ones previously present and able to regrow rapidly from unburned plant structures (base of tussocks, rhizomes, roots) were represented by species like Betula glandulosa Michx. or Carex aquatilis Wahlenb. The wetter conditions and lower fuel availability of fen depressional biotopes were important factors controlling the resistance and regeneration of species associated with them.
Identification of the cosmogenic $$^{11}$$C background in large volumes of liquid scintillators with Borexino
Authors: Agostini M. , Altenmüller K. , Appel S. , Atroshchenko V. , Bagdasarian Z. , Basilico D. , Bellini G. , Benziger J. , Biondi R. , Bravo D. , Caccianiga B. , Calaprice F. , Caminata A. , Cavalcante P. , Chepurnov A. , D’Angelo D. , Davini S. , Derbin A. , Di ZGiacintio A. , Di Marcello V. , Ding X. F. , Di Ludovico A. , Di Noto L. , Drachnev I. , Formozov A. , Franco D. , Galbiati C. , Ghiano C. , Giammarchi M. , Goretti A. , Göttel A. S. , Gromov M. , Guffanti D. , Ianni Aldo , Ianni Andrea , Jany A. , Jeschke D. , Kobychev V. , Korga G. , Kumaran S. , Laubenstein M. , Litvinovich E. , Lombardi P. , Lomskaya I. , Ludhova L. , Lukyanchenko G. , Lukyanchenko L. , Machulin I. , Martyn J. , Meroni E. , Meyer M. , Miramonti L. , Misiaszek M. , Muratova V. , Neumair B. , Nieslony M. , Nugmanov R. , Oberauer L. , Orekhov V. , Ortica F. , Pallavicini M. , Papp L. , Pelicci L. , Penek Ö. , Pietrofaccia L. , Pilipenko N. , Pocar A. , Porcelli A. , Raikov G. , Ranalli M. T. , Ranucci G. , Razeto A. , Re A. , Redchuk M. , Romani A. , Rossi N. , Schönert S. , Semenov D. , Settanta G. , Skorokhvatov M. , Singhal A. , Smirnov O. , Sotnikov A. , Suvorov Y. , Tartaglia R. , Testera G. , Thurn J. , Unzhakov E. , Vishneva A. , Vogelaar R. B. , von Feilitzsch F. , Wojcik M. , Wurm M. , Zavatarelli S. , Zuber K. , Zuzel G.
Published: December 2021

Cosmogenic radio-nuclei are an important source of background for low-energy neutrino experiments. In Borexino, cosmogenic $$^{11}$$

11

C decays outnumber solar pep and CNO neutrino events by about ten to one. In order to extract the flux of these two neutrino species, a highly efficient identification of this background is mandatory. We present here the details of the most consolidated strategy, used throughout Borexino solar neutrino measurements. It hinges upon finding the space-time correlations between $$^{11}$$

11

C decays, the preceding parent muons and the accompanying neutrons. This article describes the working principles and evaluates the performance of this Three-Fold Coincidence (TFC) technique in its two current implementations: a hard-cut and a likelihood-based approach. Both show stable performances throughout Borexino Phases II (2012–2016) and III (2016–2020) data sets, with a $$^{11}$$

11

C tagging efficiency of $$\sim 90$$

∼
90

 % and $$\sim $$
∼
 63–66 % of the exposure surviving the tagging. We present also a novel technique that targets specifically $$^{11}$$

11

C produced in high-multiplicity during major spallation events. Such $$^{11}$$

11

C appear as a burst of events, whose space-time correlation can be exploited. Burst identification can be combined with the TFC to obtain about the same tagging efficiency of $$\sim 90\%$$

∼
90
%

but with a higher fraction of the exposure surviving, in the range of $$\sim $$
∼
 66–68 %.
Reheating after inflation by supersymmetry breaking
Authors: Aldabergenov Yermek , Antoniadis Ignatios , Chatrabhuti Auttakit , Isono Hiroshi
Published: December 2021

We study reheating after the end of inflation in models where the inflaton is the superpartner of goldstino and is charged under a gauged U(1) R-symmetry. We consider two classes of models – one is small field characterized by an almost flat Kähler space, and the other large field characterized by a hyperbolic Kähler space SU(1, 1)/U(1), while in both cases the inflaton superpotential is linear due to the R-symmetry. The inflationary observables of our models fit within 2$$\sigma $$
σ
CMB values. Upon coupling the inflaton sector to the (supersymmetric) Standard Model, we compute the MSSM parameters, mass spectrum, and decay modes of the inflaton, with the resulting reheating temperature around $$10^8$$

10
8

GeV. We also find that both models can accommodate superheavy LSP dark matter, depending on the parameter choice.
$$a_{1}$$ meson-nucleon coupling constant at finite temperature from the soft-wall AdS/QCD model
Authors: Mamedov Shahin , Taghiyeva Shahnaz
Published: December 2021

We study the temperature dependence of the $$a_1$$

a
1

meson-nucleon coupling constant in the framework of the soft-wall AdS/QCD model with thermal dilaton field. Profile functions for the axial-vector and fermion fields in the AdS-Schwarzschild metric are presented. It is constructed an interaction Lagrangian for the fermion-axial-vector-thermal dilaton fields system in the bulk of space-time. From this Lagrangian integral representation for the $$g_{a_1NN}$$

g

a
1

N
N

coupling constant is derived. The temperature dependence of this coupling constant is numerically analyzed.
Graph Connectivity in Log Steps Using Label Propagation
Authors: Burkhardt Paul
Published: December 2021

The fastest deterministic algorithms for connected components take logarithmic time and perform superlinear work on a Parallel Random Access Machine (PRAM). These algorithms maintain a spanning forest by merging and compressing trees, which requires pointer-chasing operations that increase memory access latency and are limited to shared-memory systems. Many of these PRAM algorithms are also very complicated to implement. Another popular method is “leader-contraction” where the challenge is to select a constant fraction of leaders that are adjacent to a constant fraction of non-leaders with high probability, but this can require adding more edges than were in the original graph. Instead we investigate label propagation because it is deterministic, easy to implement, and does not rely on pointer-chasing. Label propagation exchanges representative labels within a component using simple graph traversal, but it is inherently difficult to complete in a sublinear number of steps. We are able to overcome the problems with label propagation for graph connectivity.

We introduce a surprisingly simple framework for deterministic, undirected graph connectivity using label propagation that is easily adaptable to many computational models. It achieves logarithmic convergence independently of the number of processors and without increasing the edge count. We employ a novel method of propagating directed edges in alternating direction while performing minimum reduction on vertex labels. We present new algorithms in PRAM, Stream, and MapReduce. Given a simple, undirected graph [Formula: see text] with [Formula: see text] vertices, [Formula: see text] edges, our approach takes O(m) work each step, but we can only prove logarithmic convergence on a path graph. It was conjectured by Liu and Tarjan (2019) to take [Formula: see text] steps or possibly [Formula: see text] steps. Our experiments on a range of difficult graphs also suggest logarithmic convergence. We leave the proof of convergence as an open problem.
DOES LAND EXPROPRIATION INCREASE HOUSEHOLD CONSUMPTION AND SAVINGS RATE? EVIDENCE FROM RURAL CHINA
Authors: ZHAO XUECUN , HU FENG
Published: December 2021

This paper estimates how land expropriation affects household consumption and savings rate using a nationally representative household data from China. We argue that land expropriation is likely to be random across households within the same village. We find that land expropriation has positive and statistically significant effects on per capita household consumption and savings rate. The effects on consumption of durable goods and on savings rate, however, weaken and become insignificant over time.
Discrete phase space and continuous time relativistic quantum mechanics II: Peano circles, hyper-tori phase cells, and fiber bundles
Authors: Das Anadijiban , Chatterjee Rupak
Published: December 2021

The discrete phase space and continuous time representation of relativistic quantum mechanics are further investigated here as a continuation of paper I.1 The main mathematical construct used here will be that of an area filling Peano curve. We show that the limit of a sequence of a class of Peano curves is a Peano circle denoted as [Formula: see text], a circle of radius [Formula: see text] where [Formula: see text]. We interpret this two-dimensional (2D) Peano circle in our framework as a phase cell inside our 2D discrete phase plane. We postulate that a first quantized Planck oscillator, being very light, and small beyond current experimental detection, occupies this phase cell [Formula: see text]. The time evolution of this Peano circle sweeps out a 2D vertical cylinder analogous to the worldsheet of string theory. Extending this to 3D space, we introduce a [Formula: see text]-dimensional phase space hyper-tori [Formula: see text] as the appropriate phase cell in the physical dimensional discrete phase space. A geometric interpretation of this structure in state space is given in terms of product fiber bundles.

We also study free scalar Bosons in the background [Formula: see text]-dimensional discrete phase space and continuous time state space using the relativistic partial difference-differential Klein–Gordon equation. The second quantized field quanta of this system can cohabit with the tiny Planck oscillators inside the [Formula: see text] phase cells for eternity. Finally, a generalized free second quantized Klein–Gordon equation in a higher [Formula: see text]-dimensional discrete state space is explored. The resulting discrete phase space dimension is compared to the significant spatial dimensions of some of the popular models of string theory.
Modified Newtonian dynamics and hadronic scales
Authors: Żenczykowski Piotr
Published: December 2021

In this paper, we use the idea of modified Newtonian dynamics to further support the arguments that important information concerning the nature of space is hidden at hadronic mass and distance scales.
Investigating Distributional Chaos for Operators on Fréchet Spaces
Authors: Yin Zongbin , Li Lianmei , Wei Yongchang
Published: December 2021

In this paper, various notions of chaos for continuous linear operators on Fréchet spaces are investigated. It is shown that an operator is Li–Yorke chaotic if and only if it is mean Li–Yorke chaotic in a sequence whose upper density equals one; that an operator is mean Li–Yorke chaotic if and only if it admits a mean Li–Yorke pair, if and only if it is distributionally chaotic of type 2, if and only if it has an absolutely mean irregular vector. As a consequence, mean Li–Yorke chaos is not conjugacy invariant for continuous self-maps acting on complete metric spaces. Moreover, the existence of invariant scrambled sets (with respect to certain Furstenberg families) of a class of weighted shift operators is proved.
Limit Cycles on Piecewise Smooth Vector Fields with Coupled Rigid Centers
Authors: Carvalho Tiago , Gonçalves Luiz Fernando , Llibre Jaume
Published: December 2021

We provide an upper bound for the maximum number of limit cycles of the class of discontinuous piecewise differential systems formed by two differential systems separated by a straight line presenting rigid centers. These two rigid centers are polynomial differential systems with a linear part and a nonlinear homogeneous part. We study the maximum number of limit cycles that such a class of piecewise differential systems can exhibit.
Regularization of Planar Piecewise Smooth Systems with a Heteroclinic Loop
Authors: Wang Zhongjian , Pi Dingheng
Published: December 2021

In this paper, we study bifurcations of the regularized systems of planar piecewise smooth systems, which have a visible fold-regular point and a sliding or grazing heteroclinic loop. Our results show that if the planar piecewise smooth system with a sliding heteroclinic loop undergoes sliding heteroclinic bifurcation, then the regularized system can bifurcate with a stable limit cycle passing through the regularized region and at most two limit cycles outside the regularized region. The regularized system can have at most three periodic orbits. When the upper subsystem is a Hamiltonian system, the regularized system can bifurcate with a semi-stable periodic orbit. Finally, we discuss two cases when the heteroclinic loop of a piecewise smooth system remains unbroken under a small perturbation. Our results show that the regularized system can bifurcate at most two limit cycles from an inner unstable grazing heteroclinic loop.
The Art Gallery Problem is ∃ℝ-complete
Authors: Abrahamsen Mikkel , Adamaszek Anna , Miltzow Tillmann
Published: December 2021

The
Art Gallery Problem
(AGP) is a classic problem in computational geometry, introduced in 1973 by Victor Klee. Given a simple polygon 풫 and an integer
k
, the goal is to decide if there exists a set
G
of
k
guards
within 풫 such that every point
p
∈ 풫 is seen by at least one guard
g
∈
G
. Each guard corresponds to a point in the polygon 풫, and we say that a guard
g
sees
a point
p
if the line segment
pg
is contained in 풫.

We prove that the AGP is ∃ ℝ-complete, implying that (1) any system of polynomial equations over the real numbers can be encoded as an instance of the AGP, and (2) the AGP is not in the complexity class NP unless NP = ∃ ℝ. As a corollary of our construction, we prove that for any real algebraic number α, there is an instance of the AGP where one of the coordinates of the guards equals α in any guard set of minimum cardinality. That rules out many natural geometric approaches to the problem, as it shows that any approach based on constructing a finite set of candidate points for placing guards has to include points with coordinates being roots of polynomials with arbitrary degree. As an illustration of our techniques, we show that for every compact semi-algebraic set
S
⊆ [0, 1]
2
, there exists a polygon with corners at rational coordinates such that for every
p
∈ [0, 1]
2
, there is a set of guards of minimum cardinality containing
p
if and only if
p
∈
S
.

In the ∃ ℝ-hardness proof for the AGP, we introduce a new ∃ ℝ-complete problem ETR-INV. We believe that this problem is of independent interest, as it has already been used to obtain ∃ ℝ-hardness proofs for other problems.
Behavior Trees in Robot Control Systems
Authors: Ögren Petter , Sprague Christopher I.
Published: December 2021

In this article, we provide a control-theoretic perspective on the research area of behavior trees in robotics. The key idea underlying behavior trees is to make use of modularity, hierarchies, and feedback in order to handle the complexity of a versatile robot control system. Modularity is a well-known tool to handle software complexity by enabling the development, debugging, and extension of separate modules without detailed knowledge of the entire system. A hierarchy of such modules is natural, since robot tasks can often be decomposed into a hierarchy of subtasks. Finally, feedback control is a fundamental tool for handling uncertainties and disturbances in any low-level control system, but in order to enable feedback control on the higher level, where one module decides what submodule to execute, information regarding the progress and applicability of each submodule needs to be shared in the module interfaces. We describe how these three concepts can be used in theoretical analysis, practical design, and extensions and combinations with other ideas from control theory and robotics.
Facile Synthesis of β-PbO2 Nanoparticles Range from 10–30 nm and their Application for Ozone Generation
Authors: Du Yuan , Hao Liu , Zixuan Wang , Xi Wang , Guirong Miao , Xu Wu
Published: December 2021

β-PbO2 is an important high oxygen overpotential anode coating material. Further study on nanoscale β-PbO2 with higher performance and lower cost is a critical issue in order to develop the electrochemical ozone generator. Herein, an improved β-PbO2 nanoparticles synthesizing strategy based on the traditional Pb(OAc)4 hydrolysis method is proposed in this work, which is more scalable for industrial-scale production compared with existed nano β-PbO2 synthesizing methods. The possible mechanism of synthesizing β-PbO2 nanoparticles via Pb(OAc)4 hydrolysis was discussed for the first time. Based on the proposed mechanism, the size and morphology of the β-PbO2 nanoparticles were effectively controlled, and alternative raw material that can significantly reduce costs was developed. SEM, TEM, XRD, and XPS results indicate that pure phase β-PbO2 nanoparticles range from 10–30 nm were obtained. In addition, the use of alternative raw materials reduces the cost by 90%–95% compared to the traditional Pb(OAc)4 hydrolysis method. The β-PbO2 nanoparticles showed good ozone generation performances. The energy consumption per unit ozone of the β-PbO2 nanoparticles is reduced by 51.9% at the optimized operation condition than the reference PbO2 particles used for comparison.
Simultaneous Electrochemical Detection of Multiple Heavy-Metal Ions Based on Furfural/Reduced Graphene Oxide Composites
Authors: Xu Xiaoyun , Lv Xiaoyi , Tan Fei , Li Yanping , Geng Chao , Cui Bo , Fang Yishan
Published: December 2021

An efficient and sensitive electrochemical sensor for simultaneous detection of heavy metal ions was developed based on furfural/reduced graphene oxide composites (FF/RGO). The preparation of FF/RGO were performed through a one-step high-pressure assisted hydrothermal treatment, which is recommended as a green, convenient, and efficient way for the reduction of graphene oxide and the production of FF/RGO composites. RGO not only serves as the skeleton for furfural loading but also improves the conductivity of the composites in the matrix. FF/RGO with large specific surface area and abundant oxygen-containing functional groups was used to provide more binding sites for the effificient adsorption of heavy-metal ions due to the interaction between hydrophilic groups (–COOH, –OH, and –CHO) and metal cations. The developed sensor showed identifiable electrochemical response toward the heavy metal ions separately and simultaneously, exhibiting superior stability, outstanding sensitivity, selectivity and excellent analytical performance. Impressively, the sensor developed in this experiment has been successfully applied to the simultaneous determination of various heavy metal ions in actual samples, which has definitely exhibited a promising prospect in practical application.
Prediction of Dielectric Breakdown of OHTL Insulators Using Contact Angle Measurements
Authors: Kim Taeyong , Sanyal Simpy , Jeon Seongho , Yi Junsin
Published: December 2021

Porcelain insulators used in overhead transmission lines (OHTL) are exposed to pollution when operational. To observe the effect of external pollution on these insulators, the relationship between the flashover voltage and surface contamination was studied. The flashover voltage drops sharply when contaminants in the wind are deposited on the surface of the insulators in a humid environment. Under wet conditions, the flashover voltage demonstrates a difference of approximately 10 kV depending on the contamination levels. The higher the equivalent salt deposit density, the lower the contact angle. In particular, the flashover voltage under wet conditions decreases exponentially when the contact angle is below 30°. In this case, the condensation area becomes considerably wider, thus exhibiting the difference in the area of the electrolytic conductive film layer forming the leakage path on the surface. Depending on the equivalent salt deposit density and contact angle, the area of condensation is more than doubled. To measure the level of contamination on the surface using this principle, a contact angle measurement method was adopted to predict the dielectric breakdown of the insulator.
Fabrication of Inkjet-Printed Carbon Nanotube for Enhanced Mechanical and Strain-Sensing Performance
Authors: Chen Chun-Bing , Kao Hsuan-Ling , Chang Li-Chun , Cho Cheng-Lin , Lin Yi-Chen , Huang C.-C. , Mo C.-C. , Chung Wen-Hung , Chiu Hsien-Chin
Published: December 2021

This paper presents fabrication of inkjet-printed carbon nanotube film on flexible substrate for wearable electronics applications. The density of CNT films is optimized by droplet spacing (DS) and multiple passes to provide the best strain behavior. It is found that low-density carbon nanotubes have fewer conductive pathways resulting in less change and low GF under applied strain. Conversely, high-density carbon nanotubes have more conductive paths, and they are not easily broken under strain, resulting in poor strain-sensing ability. The inkjet printing process can adjust uniformity and density of CNT film through DS and multiple passes to optimize its strain characteristics. The highest GF of 3.36 was obtained under strain ranging from 71 to 3128 με when CNT printed by DS of 23 μm and 20 passes. The relative change in resistance under various strains, ranging from 71 to 3128 με, had a stable peak value for each 20 strain/release cycle which proved its repeatability and stability. Furthermore, inkjet-printed CNT sensors monitored human movement of various joints and distinguished bending angle demonstrating its potentially practical application in wearable electronics.
Preparation of Ceria-Coated Silica Nanoparticles and Their Chemical Mechanical Planarization Performance on Si-Face 6H-SiC Substrates
Authors: Ni Zifeng , Chen Guomei , Xu Laijun , Zhang Ping , Dai Mengjiao , Qian Shanhua , Bian Da , Zhang Haitao
Published: December 2021

Ceria-coated silica (SiO2/CeO2) composite abrasives were prepared through a novel homogeneous precipitation method using commercial silica (SiO2) sol as the silicon resource and cerium nitrate (Ce(NO3)3) and hexamethylenetetramine (HMT) aqueous mixtures as coating precursors. The phase composition, nano-topography, size distribution, and chemical structure of as-prepared particles were characterized by X-ray diffraction, transmission electron microscopy, Zetasizer Nano ZS90 and Fourier infrared spectra. In addition, the possible coating mechanism was discussed. Then, chemical mechanical planarization behaviors of SiO2 sol, ceria (CeO2) sol, and the novel abrasives and on Si-face (0001) 6H-SiC were investigated by atomic force microscopy. The results indicated that the composite particles were mono-dispersed nano-spheres composed of amorphous SiO2 core and cubic fluorite CeO2 shell, possessing complete core–shell structure and particle size of about 110 nm. CeO2 shell (10 nm) grew on the surface of SiO2 core by formation of Ce–O–Si chemical bonds, forming stable core–shell structure. SiO2/CeO2 composite abrasives provided an exponentially high material remove rate (MRR) of 1207 nm h−1 and an impressive surface finish with roughness average (Ra) 0.216 nm due to its active chemical property and unique structure.
Comparison of Marginal and Internal Adaptation in Endocrowns Milled from Translucent Zirconia and Zirconium Lithium Silicate
Authors: Amini Amirhesam , Zeighami Somayeh , Ghodsi Safoura
Published: December 2021

Purpose. This study aimed to compare marginal and internal adaptation in endocrowns made from translucent zirconia and zirconium lithium silicate using CAD-CAM technology. Materials and Methods. Twenty-eight freshly extracted upper molars were mounted in acrylic resin and underwent root canal therapy and endocrown preparation up to 2 mm above the cementoenamel junction. Endocrowns were CAD-CAM milled from zirconium lithium silicate (ZLS) and translucent zirconia (Zr). Internal and marginal adaptation was assessed by the replica technique before cementation. Marginal adaptation was evaluated by a stereomicroscope (×32) before and after cementation and also after thermomechanical aging. Results. The ZLS group showed significantly higher internal adaptation compared to the Zr group (

P

 = 0.028), while the marginal adaptation differences, at different times with different methods, were not statistically significant (

P

 > 0.05). Axiomarginal angle had the highest and axiopulpal angle showed the lowest adaptation in both groups. The cementation process and thermomechanical aging increased the marginal gap in both groups significantly (

P

 < 0.001). The marginal gap assessed by the replica technique before cementation was 7.11 µm higher than direct view under a stereomicroscope with intraclass correlation coefficient of 0.797. Conclusion. Zirconia seems to be an acceptable material for endocrown with comparable internal and marginal adaptation to ZLS. Cementation and thermomechanical aging had significantly negative effects on marginal gap. The marginal gap assessed by the replica technique was higher than direct view under the stereomicroscope technique.