bluuebunny/crossref_metadata_2025 huggingface dataset:
Is it time we split bowel preparation for all colonoscopies? Outcomes from a national survey of bowel preparation practice in the UK
Authors: Archer Thomas , Shirazi-Nejad Ahmad Reza , Al-Rifaie Ammar , Corfe Bernard M , Riley Stuart , Thoufeeq Mo
Published: October 2021

Introduction

Adequate bowel preparation is a prerequisite for effective colonoscopy. Split bowel preparation results in optimal cleansing. This study assessed the bowel preparation regimes advised by endoscopy units across the UK, and correlated the differences with outcomes.

Methods

Trusts in the UK were surveyed, with data requested between January 2018 and January 2019, including: the type and timing of preparation, pre-endoscopy diet, adequacy rates and polyp detection. Trusts were grouped according to the timing of bowel preparation. χ2test was used to assess for differences in bowel preparation adequacy.

Results

Moviprep was the first line bowel preparation in 79% of trusts. Only 7% of trusts advised splitting bowel preparation for all procedures, however, 91% used split bowel preparation for afternoon procedures. Trusts that split preparation for all procedures had an inadequacy rate of 6.7%, compared with 8.5% (p<0.001) for those that split preparation for PM procedures alone and 9.5% (p<0.001) for those that provided day before preparation for all procedures. Morning procedures with day-before preparation had a higher rate of inadequate cleansing than afternoon procedures that received split preparation (7.7% vs 6.5 %, p<0.001). The polyp detection rate for procedures with adequate preparation was 37.1%, compared with 26.4% for those that were inadequate.

Conclusion

Most trusts in the UK do not provide instructions optimising the timing of bowel preparation prior to colonoscopy. This correlated with an increased rate of inadequate cleansing. Splitting bowel preparation is likely to reduce the impacts of poor cleansing: missed lesions, repeat colonoscopies and significant costs.
Defining frugal innovation: a critical review
Authors: Hindocha Chandni N , Antonacci Grazia , Barlow James , Harris Matthew
Published: October 2021

Frugal innovation (FI), which has gained traction in various sectors, is loosely defined as developing quality solutions in a resource-constrained environment that are affordable to low-income consumers. However, with its popularity, multiple and diverse definitions have emerged that often lack a theoretical foundation. This has led to a convoluted conceptualisation that hinders research and adoption in practice. Despite this plethora of perspectives and definitions, scholars do agree that there is a need for a unified definition. This critical review across the management, entrepreneurship, business and organisation studies literatures explores the multiple definitions of FI that have appeared in the last two decades and seeks to examine the commonalities and differences. One definition is supported by a theoretical underpinning, and main themes include affordability, adaptability, resource scarcity, accessibility and sustainability, however, there remains significant ambiguity around what constitutes an FI. Defining FI as a concept should not deter from focusing on its core aim and identifying an FI may be best achieved by comparing it to an incumbent alternative, rather than against an ill-defined concept. There is merit in developing a common understanding of FI to support strategies for its successful acceptance and diffusion globally.
A pilot randomised controlled trial of a structured, home-based exercise programme on cardiovascular structure and function in kidney transplant recipients: the ECSERT study design and methods
Authors: Billany Roseanne E , Vadaszy Noemi , Bishop Nicolette C , Wilkinson Thomas J , Adenwalla Sherna F , Robinson Katherine A , Croker Kathryn , Brady Emer M , Wormleighton Joanne V , Parke Kelly S , Cooper Nicola J , Webster Angela C , Barratt Jonathan , McCann Gerry P , Burton James O , Smith Alice C , Graham-Brown Matthew PM
Published: October 2021

Background

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in kidney transplant recipients (KTRs). CVD risk scores underestimate risk in this population as CVD is driven by clustering of traditional and non-traditional risk factors, which lead to prognostic pathological changes in cardiovascular structure and function. While exercise may mitigate CVD in this population, evidence is limited, and physical activity levels and patient activation towards exercise and self-management are low. This pilot study will assess the feasibility of delivering a structured, home-based exercise intervention in a population of KTRs at increased cardiometabolic risk and evaluate the putative effects on cardiovascular structural and functional changes, cardiorespiratory fitness, quality of life, patient activation, healthcare utilisation and engagement with the prescribed exercise programme.

Methods and analysis

Fifty KTRs will be randomised 1:1 to: (1) the intervention; a 12week, home-based combined resistance and aerobic exercise intervention; or (2) the control; usual care. Intervention participants will have one introductory session for instruction and practice of the recommended exercises prior to receiving an exercise diary, dumbbells, resistance bands and access to instructional videos. The study will evaluate the feasibility of recruitment, randomisation, retention, assessment procedures and the intervention implementation. Outcomes, to be assessed prior to randomisation and postintervention, include: cardiac structure and function with stress perfusion cardiac MRI, cardiorespiratory fitness, physical function, blood biomarkers of cardiometabolic health, quality of life and patient activation. These data will be used to inform the power calculations for future definitive trials.

Ethics and dissemination

The protocol was reviewed and given favourable opinion by the East Midlands-Nottingham 2 Research Ethics Committee (reference: 19/EM/0209; 14 October 2019). Results will be published in peer-reviewed academic journals and will be disseminated to the patient and public community via social media, newsletter articles and presentations at conferences.

Trial registration number

NCT04123951.
Prevalence of disposable pod use and consumer preference for e-cigarette product characteristics among vape shop customers in Southern California: a cross-sectional study
Authors: Galimov Artur , Leventhal Adam , Meza Leah , Unger Jennifer B. , Huh Jimi , Baezconde-Garbanati Lourdes , Sussman Steven Y
Published: October 2021

Objectives

In February 2020, the US Food and Drug Administration issued a guidance restricting the sales and distribution of cartridge-based e-cigarettes with flavours other than tobacco and menthol. Disposable devices were exempt from this guidance. This study examined the prevalence of disposable pod use and flavour preference compared with refillable pod and other e-cigarette users among vape shop customers.

Design

Cross-sectional study.

Setting

In July 2019–March 2020, trained data collectors visited 44 vape shops in California with permission to recruit customers from shop owners.

Participants

Intercept interviews with 276 customers were conducted.

Outcomes and procedures

Customers were grouped based on self-reported device type used most often (disposable pod, refillable pod and other e-cigarettes). Groups were compared on self-reported demographics, flavours preferred, daily e-cigarette use, preferred nicotine concentration levels and cigarette use.

Results

Of the 276 customers surveyed, 11.2% used disposable pods in the past 30 days. Among disposable pod users, fruit/candy (80.7%), mint (77.4%) and menthol (67.7%) were common preferred flavours, while tobacco flavours were less commonly preferred (19.4%). When compared with refillable pod and other non-pod e-cigarette device users, disposable pod users were younger, used higher nicotine concentration levels, were more likely to prefer mint and menthol flavours and use e-cigarettes as their first product, while less likely to ever use cigarettes and use e-cigarettes daily.

Discussion

Despite using higher nicotine levels and preferred menthol/mint flavours more often than users of other devices, disposable pod users reported lower prevalence of lifetime smoking and daily vaping and were younger. Given the current findings, regulations addressing non-tobacco flavours and nicotine concentration in disposable pod devices merit consideration in efforts to reduce vaping in younger adult never smokers.
Development and validation of risk-adjusted outcomes for systems of emergency care: the DAVROS study
Authors: Goodacre Steve
Published: October 2021

Background

The (Development and validation of risk-adjusted outcomes for systems of emergency care) DAVROS study aims to develop a method to predict the probability of mortality for patients admitted to hospital as a medical emergency. This would facilitate evaluation of the performance of emergency care systems through comparison of actual to predicted mortality.

Methods

We collected data on presenting physiology, demographic data, co-morbidities, blood tests and mortality from the ambulance patient report form, emergency department notes and hospital computer records of 11 528 emergency medical admissions to three hospitals in South Yorkshire. These data are used to develop risk-adjustment models to predict 7-day and 30-day mortality.

Results

Mortality was 630/11 528 (5.5%) at 7 days and 1068/11 528 (9.3%) at 30 days. Univariate analysis has identified predictor variables associated with 7 and 30-day mortality and multivariable analysis has identified independent predictor variables. Preliminary analysis suggests a model based on demographics, co-morbidities and International Classification of Diseases code has a c-statistic of 0.766 for 7-day mortality and 0.776 for 30-day mortality. The addition of physiological parameters increases these values to 0.852 and 0.835, respectively. We will present the DAVROS risk-prediction model for 7 and 30-day mortality, derived on half the cohort and validated on the other half, with estimates of discriminant value (c-statistic) and calibration (Hosmer-Lemeshow).

Conclusion

A risk-adjustment model based on demographic data, co-morbidities and baseline physiology can predict 7 and 30-day mortality in emergency medical admissions with acceptable discriminatory power.
Systemic inflammation at 24 h predicts outcome in patients after out-of-hospital cardiac arrest treated with therapeutic hypothermia
Authors: Clegg Gareth
Published: October 2021

Introduction

Only mild therapeutic hypothermia (MTH) is shown to improve outcome after return of spontaneous circulation, post out of hospital cardiac arrest (OHCA), though its mechanism remains unknown. We hypothesise that the benefit of MTH is mediated through modulation of the inflammatory response.

Methods

During our prospective observational study from Aug 2008 to October 2009, 196 OHCA patients were enrolled. 173 were eligible for inclusion; 115 died in Emergency Department (ED), 38 died in intensive care unit (ICU) and 20 survived to discharge. Patients had blood sampled on arrival in the ED and at 24 h, 72 h and 5 days. A small subgroup of patients had blood sampled prehospital during the initial resuscitation phase. Serum levels of cytokines important in the regulation of inflammation (interleukin 6 (IL-6), IL-8, IL-10) were measured along with markers of neutrophil activation (elastase and CD 11b). All patients who reached the ICU had MTH induced and were maintained at 32–34° for 24 h.

Results

Levels of the pro-inflammatory cytokine IL-8 were significantly higher at 24 h after return of spontaneous circulation in patients who died in ICU, compared to those who survived to discharge (478.1 pg/ml (CI 171.1 to 831.1) cf 108.0 pg/ml (CI 44.8 to 171.1) p=0.03). Serum levels of the ‘anti’-inflammatory cytokine IL-10 were also much higher in non-survivors (CI 80.9 pg/ml (22.3 to 139.4) cf CI 10.2pg/ml (3.6 to 16.8) p=0.002). IL-10 predicted survival 24 h with an area under the Receiver Operating Characteristic of 0.91 (CI 0.77 to 1.0, p<0.001), and a sensitivity of 100%, specificity 75% at a cut off of 32 pg/ml, LR 4.0. Indicators of neutrophil activation, were markedly elevated in all patients on arrival in the ED.

Discussion

OHCA is associated with massive systemic inflammation. We have shown that this begins much earlier than previously described, and that levels of both the classically pro-inflammatory and counterregulatory chemokines predict survival. Our findings are consistent with the hypothesis that MTH works, at least in part, by modulating the inflammation.
Unscheduled re-attendances to a paediatric Emergency Department: an audit
Authors: Black Lisa
Published: October 2021

Introduction

Unscheduled re-attendances (UR) continue to pose a problem to the Paediatric Emergency Department (PED) and there is paucity of research on this topic. 5% of PED attendances are UR.1 Although some are inevitable, it is important to identify strategies to minimise such attendances.

Objectives

To estimate the size of the problem, identify high risk patient groups and determine other factors (system or doctor) related to UR within an inner city PED.

Methods

All patients under the age of 17, who reattended within 72 h, over a 28-day period, were identified and their Emergency Department notes reviewed.

Results

91 children were identified, which represented an UR rate of 3.88%, of which 69 (76%) were under 5 years old. Gastroenteritis (GE) and upper respiratory tract infection (URTI) were the predominant causes of UR. 67% of children were assessed by a junior doctor (JD {< ST2}) on initial presentation. On re-attendance, 74% were again assessed by a JD contrary to department policy and on both occasions less than half were discussed with a senior doctor. Only 70% were discharged with a documented safety net advising appropriate re-attendance. Four children had a revised diagnosis on re-attendance and 22% were ultimately admitted.

Conclusions

UR is an important performance indicator and a periodic review should be a part of clinical governance activity. High risk groups for UR were <5 s, GE and URTI. We suggest that improved discharge information for parents with expected disease course, better supervision of JD / initial senior review and better collaboration with primary care providers may decrease such UR.
The effectiveness of patient self-assessment forms at increasing emergency department efficiency
Authors: Middleton Scott
Published: October 2021

Introduction

Emergency department ergonomics is an under researched topic. To our knowledge, this is the only study investigating the effectiveness of a patient self-assessment form in managing patient flow through an emergency department in a busy teaching hospital.

Methods

Self-reported information contained on the forms included patient demographics, presenting complaint, past medical, surgical and drug history, and the option to consent for the emergency care summary, which provides an up-to-date drug history from the general practitioner. This form followed the patient through the department and was utilised by the triage nurse and care providers. 200 patients in Manchester triage categories three to five were recruited, half of whom were given self-assessment forms. Time spent in triage, time taken for first assessment and total time in the department were recorded for all patients.

Results

Patients without a self-assessment form had a mean time spent in triage of 6.0± 3.6 SD min and mean time taken for first assessment of 11.0±6.0 SD min. Patients managed with a self-assessment form had a mean time spent in triage of 4.9 ±3.5 SD min and mean time taken for first assessment of 9.0±5.0 SD min. Patients without a self-assessment form had a median total time spent in the department of 201 min (range 33–301), whereas patients managed with the self-assessment form had a median time of 121 min (range 19–240). The differences in triage, first assessment and total department times between groups were significant (p<0.05).

Conclusion

This pilot study showed the effectiveness of a self-assessment form at increasing patient flow through the department, reducing triage, first assessment and total department times. The reasons for this are complex and merit further investigation.
UK Research Ethics Committee’s review of the global first SARS-CoV-2 human infection challenge studies
Authors: Davies Hugh
Published: October 2021

This paper describes the UK Research Ethics Committee’s (REC) preparations and review of the global first SARS-CoV-2 human infection challenge studies. To frame our review, we used the WHO guidance and our UK Health Research Authority ethical review framework. The WHO criteria covered most issues we were concerned about, but we would recommend one further criterion directing RECs to consider alternative research designs. Could research questions be equally well answered by less intrusive studies? The committee met virtually, ensuring broad representation across the UK nations and also ensuring applicants could attend easily. We worked in collaboration with the applicants but while we recognise that such proximity might raise the accusation of ‘collusion’, we made every effort to maintain ‘moral distance’ and all decisions were made by the committee alone. Prior existing processes and policy facilitated training and review but even with this preparation, review took time and this could have hindered a rapid response to the emergency. Review for the various follow-on studies will now be speedier and once the pandemic has subsided, our group could be reconvened in future emergencies. In conclusion, we have tried to make decisions in good faith. We know there is controversy and disagreement and reasonable people may feel we have made the wrong decision. A more detailed analysis, built on the WHO guidance, is provided in online supplemental material.
The ARTISSE intrasaccular device for intracranial aneurysm treatment: short-term, mid-term and long-term clinical and angiographic results
Authors: Piotin Michel , Fahed Robert , Redjem Hocine , Smajda Stanislas , Desilles Jean Philippe , Escalard Simon , Maïer Benjamin , Hebert Solène , Delvoye François , Mazighi Mikael , Blanc Raphaël
Published: October 2021

Background

The concept of intra-aneurysmal flow disruption has emerged as a new paradigm for the treatment of primarily bifurcation aneurysms. The purpose of this study was to determine the clinical and angiographic outcomes of patients treated with the new ARTISSE intrasaccular device (ISD).

Methods

Selected patients with bifurcation aneurysms that matched the indications of the ARTISSE ISD defined by the manufacturer were treated in a single center. Clinical and angiographic follow-up was conducted at 6 and 36 months. Aneurysm occlusion was assessed using the Raymond–Roy classification scale.

Results

Nine subjects with nine unruptured bifurcation aneurysms were enrolled. Mean aneurysm size was 7.2±1.2 mm (range 5.5–9.7 mm). An adequate aneurysm occlusion (defined as a complete occlusion or a neck remnant) was achieved in 6/9 patients (66.7%) at 6 months and 4/7 patients (57.1%) at 36 months follow-up. Two of the nine subjects experienced a major stroke (22.2%), including one on postoperative day 1 due to a procedure-related parent vessel occlusion and subsequent ischemic stroke. The other major stroke occurred within the 36-month follow-up period during treatment of a separate aneurysm with coils, leading to perforation with hemorrhagic stroke causing a permanent neurological deficit.

Conclusion

The ARTISSE ISD was successfully deployed in all nine cases. There were, however, several procedure-related complications and results in terms of angiographic aneurysm occlusion were modest.
Intracranial aneurysm treatment with intrasaccular flow disruption: comparison of WEB-21 and WEB-17 systems
Authors: Pagano Paolo , Paiusan Laurentiu , Soize Sebastien , Pierot Laurent
Published: October 2021

Background

New generations of Woven EndoBridge (WEB) devices (WEB-21 and WEB-17) are available to treat aneurysms with a width <6.5 mm. Limited comparisons between both systems exist in the literature, but mid-term efficacy has not been compared. Our study aimed to compare the indications, feasibility, and safety of both systems and to evaluate their efficacy at mid-term follow-up (12 months).

Methods

Aneurysms treated with WEB-21 and WEB-17 were extracted from a prospective database. Patient and aneurysm characteristics, complications, and anatomical results were analyzed by an interventional neuroradiologist, independent of the procedures.

Results

From June 2015 to November 2019, 87 patients with 92 aneurysms were treated with WEB-21 (38/92, 41.3%) and WEB-17 (54/92, 58.7%). WEB-21 and WEB-17 had high treatment feasibility (97.4% and 94.4%, respectively). A higher percentage of ruptured aneurysms were treated with WEB-17 (9.3%) than with WEB-21 (2.6%; p=0.03). Morbidity and mortality at 1 month were similar in both groups (no morbidity in either group, and mortality 2.7% in the WEB-21 group and 2.0% in the WEB-17 group). The rate of complete and adequate aneurysm occlusion was not significantly higher with the WEB-17 system (59.2% and 95.9%, respectively) compared with the WEB-21 (52.9% and 85.3%, respectively).

Conclusions

This study showed the high feasibility of aneurysm treatment with both the WEB-21 and WEB-17 systems. Indications were relatively similar with both devices except for ruptured aneurysms, which were more frequently treated with the WEB-17 device. Efficacy at 12 months (complete and adequate occlusions) was slightly, but not significantly, better with the WEB-17 device.
Speckle tracking strain and ECG heterogeneity correlate in transcatheter aortic valve replacement-induced left bundle branch blocks and right ventricular paced rhythms
Authors: Burke Gordon M , Araujo Silva Bruna , Marum Alexandre A , Bortolotto Alexandre L , Nearing Bruce D , Chen Michael J , Fostello Sarah , Popma Jeffrey J , Verrier Richard L , Chang James D
Published: October 2021

Objective

Transcatheter aortic valve replacement (TAVR) complications include left bundle branch block (LBBB) and right ventricular paced rhythm (RVP). We hypothesised that changes in electrocardiographic heterogeneity would correlate better with speckle tracking strain measures than with left ventricular ejection fraction (LVEF) on transthoracic echocardiogram (TTE) among patients with TAVR-induced conduction abnormalities.

Methods

We reviewed medical records of 446 consecutive patients who underwent TAVR at our institution. Of the 238 patients with 12-lead electrocardiograms (ECGs) that met our inclusion criteria, 58 had pre-TAVR and post-TAVR TTEs adequate for strain assessment. We compared patients who did not have an LBBB or RVP pre-TAVR and post-TAVR (controls, n=11) with patients who developed LBBBs (n=11) and who required RVPs (n=10) post-TAVR. In our study population (n=32, 41% female, mean age 85.8 years), we evaluated QRS complex duration, R-wave heterogeneity (RWH), T-wave heterogeneity (TWH), LVEF, global longitudinal strain (GLS) and mechanical dispersion (MD).

Results

TAVR-induced changes on ECG did not correlate with LVEF. TAVR-induced changes in MD and QRS complex duration correlated among all patients (r=0.4, p=0.04). GLS and RWH correlated among RVP patients (r=0.7, p=0.00003). MD and TWH correlated among LBBB patients (r=0.7, p=0.00004).

Conclusions

In this convenience sample of patients with TAVR-induced conduction abnormalities, RWH and TWH correlated with strain measures but not with LVEF. Strain measures, RWH and TWH may offer additional insights for pre-TAVR evaluation and post-TAVR clinical management.
Combined anticoagulant and antiplatelet therapy is associated with an improved outcome in hospitalised patients with COVID-19: a propensity matched cohort study
Authors: Matli Kamal , Chamoun Nibal , Fares Aya , Zibara Victor , Al-Osta Soad , Nasrallah Rabih , Salameh Pascale , Mokhbat Jacques , Ghanem Georges
Published: October 2021

Background

COVID-19 is a respiratory disease that results in a prothrombotic state manifesting as thrombotic, microthrombotic and thromboembolic events. As a result, several antithrombotic modalities have been implicated in the treatment of this disease. This study aimed to identify if therapeutic anticoagulation (TAC) or concurrent use of antiplatelet and anticoagulants was associated with an improved outcome in this patient population.

Methods

A retrospective observational cohort study of adult patients admitted to a single university hospital for COVID-19 infection was performed. The primary outcome was a composite of in-hospital mortality, intensive care unit (ICU) admission or the need for mechanical ventilation. The secondary outcomes were each of the components of the primary outcome, in-hospital mortality, ICU admission, or the need for mechanical ventilation.

Results

242 patients were included in the study and divided into four subgroups: Therapeutic anticoagulation (TAC), prophylactic anticoagulation+antiplatelet (PACAP), TAC+antiplatelet (TACAP) and prophylactic anticoagulation (PAC) which was the reference for comparison. Multivariable Cox regression analysis and propensity matching were done and showed when compared with PAC, TACAP and TAC were associated with less in-hospital all-cause mortality with an adjusted HR (aHR) of 0.113 (95% CI 0.028 to 0.449) and 0.126 (95% CI 0.028 to 0.528), respectively. The number needed to treat in both subgroups was 11. Furthermore, PACAP was associated with a reduced risk of invasive mechanical ventilation with an aHR of 0.07 (95% CI 0.014 to 0.351). However, the was no statistically significant difference in the occurrence of major or minor bleeds, ICU admission or the composite outcome of in-hospital mortality, ICU admission or the need for mechanical ventilation.

Conclusion

The use of combined anticoagulant and antiplatelet agents or TAC alone in hospitalised patients with COVID-19 was associated with a better outcome in comparison to PAC alone without an increase in the risk of major and minor bleeds. Sufficiently powered randomised controlled trials are needed to further evaluate the safety and efficacy of combining antiplatelet and anticoagulants agents or using TAC in the management of patients with COVID-19 infection.
Averaging generalized scalar-field cosmologies III: Kantowski–Sachs and closed Friedmann–Lemaître–Robertson–Walker models
Authors: Leon Genly , González Esteban , Lepe Samuel , Michea Claudio , Millano Alfredo D.
Published: October 2021

Scalar-field cosmologies with a generalized harmonic potential and matter with energy density $$\rho _m$$

ρ
m

, pressure $$p_m$$

p
m

, and barotropic equation of state (EoS) $$p_m=(\gamma -1)\rho _m, \; \gamma \in [0,2]$$

p
m

=

(
γ
-
1
)

ρ
m

,

γ
∈

[
0
,
2
]

in Kantowski–Sachs (KS) and closed Friedmann–Lemaître–Robertson–Walker (FLRW) metrics are investigated. We use methods from non-linear dynamical systems theory and averaging theory considering a time-dependent perturbation function D. We define a regular dynamical system over a compact phase space, obtaining global results. That is, for KS metric the global late-time attractors of full and time-averaged systems are two anisotropic contracting solutions, which are non-flat locally rotationally symmetric (LRS) Kasner and Taub (flat LRS Kasner) for $$0\le \gamma \le 2$$

0
≤
γ
≤
2

, and flat FLRW matter-dominated universe if $$0\le \gamma \le \frac{2}{3}$$

0
≤
γ
≤

2
3

. For closed FLRW metric late-time attractors of full and averaged systems are a flat matter-dominated FLRW universe for $$0\le \gamma \le \frac{2}{3}$$

0
≤
γ
≤

2
3

as in KS and Einstein–de Sitter solution for $$0\le \gamma <1$$

0
≤
γ
<
1

. Therefore, a time-averaged system determines future asymptotics of the full system. Also, oscillations entering the system through Klein–Gordon (KG) equation can be controlled and smoothed out when D goes monotonically to zero, and incidentally for the whole D-range for KS and closed FLRW (if $$0\le \gamma < 1$$

0
≤
γ
<
1

) too. However, for $$\gamma \ge 1$$

γ
≥
1

closed FLRW solutions of the full system depart from the solutions of the averaged system as D is large. Our results are supported by numerical simulations.
Topological sampling through windings
Authors: Albandea David , Hernández Pilar , Ramos Alberto , Romero-López Fernando
Published: October 2021

We propose a modification of the Hybrid Monte Carlo (HMC) algorithm that overcomes the topological freezing of a two-dimensional U(1) gauge theory with and without fermion content. This algorithm includes reversible jumps between topological sectors – winding steps – combined with standard HMC steps. The full algorithm is referred to as winding HMC (wHMC), and it shows an improved behaviour of the autocorrelation time towards the continuum limit. We find excellent agreement between the wHMC estimates of the plaquette and topological susceptibility and the analytical predictions in the U(1) pure gauge theory, which are known even at finite $$\beta $$
β
. We also study the expectation values in fixed topological sectors using both HMC and wHMC, with and without fermions. Even when topology is frozen in HMC – leading to significant deviations in topological as well as non-topological quantities – the two algorithms agree on the fixed-topology averages. Finally, we briefly compare the wHMC algorithm results to those obtained with master-field simulations of size $$L\sim 8 \times 10^3$$

L
∼
8
×

10
3

.
Quantum gravity corrections to the mean field theory of nucleons
Authors: Naqash Abrar Ahmed , Majumder Barun , Mitra Soumodeep , Bangle Moomin Mushtaq , Faizal Mir
Published: October 2021

In this paper, we analyze the correction to the mean field theory potential for a system of nucleons. It will be argued that these corrections can be obtained by deforming the Schrödinger’s equation describing a system of nucleons by a minimal length in the background geometry of space-time. This is because such a minimal length occurs due to quantum gravitational effects, and modifies the low energy quantum mechanical systems. In fact, as the mean field potential for the nucleons is represented by the Woods–Saxon potential, we will explicitly analyze such corrections to this potential. We will obtain the corrections to the energy eigenvalues of the deformed Schrödinger’s equation for the Woods–Saxon potential. We will also construct the wave function for the deformed Schrödinger’s equation.
Dirichlet problem for complex Hessian equations on k-pseudoconvex domains in ℂn
Authors: Zhang Qiqi
Published: October 2021

We study the regularity of weak solution to general complex Hessian equation when [Formula: see text] is not strictly pseudoconvex but [Formula: see text]-pseudoconvex of plurisubharmonic type [Formula: see text] which generalizes the result of Li who studied the Monge–Ampère equation. The regularity depends on type and some interesting gap phenomenon appear in the sharp regularity.
Topological black holes in mimetic gravity
Authors: Sheykhi Ahmad , Grunau Saskia
Published: October 2021

In this paper, we construct some new classes of topological black hole solutions in the context of mimetic gravity and investigate their properties. We study the uncharged and charged black holes, separately. We find the following novel results: (i) In the absence of a potential for the mimetic field, black hole solutions can address the flat rotation curves of spiral galaxies and alleviate the dark matter problem without invoking particle dark matter. Thus, mimetic gravity can provide a theoretical background for understanding flat galactic rotation curves through modifying Schwarzschild space–time. (ii) We also investigate the casual structure and physical properties of the solutions. We observe that in the absence of a potential, our solutions are not asymptotically flat, while in the presence of a negative constant potential for the mimetic field, the solutions are asymptotically anti-de Sitter (AdS). (iii) Finally, we explore the motion of massless and massive particles and give a list of the types of orbits. We study the differences of geodesic motion in the Einstein gravity and in mimetic gravity. In contrast to the Einstein gravity, massive particles always move on bound orbits and cannot escape the black hole in mimetic gravity. Furthermore, we find stable bound orbits for massless particles.
A stochastic resonator in a layered semiconductor device
Authors: Birhanu Tibebe , Abebe Yoseph , Demeyu Lemi , Taye Mesfin , Bekele Mulugeta
Published: October 2021

In this paper, we propose a device that picks up a periodic but weak signal by amplifying it assisted by the existing background noise. The device consists of a doped layered semiconductor with three gates that generate a one-dimensional double-well potential along the semiconductor. A laser coolant is to be shined on the other side of the central gate perpendicular to the one-dimensional layer causing triple-well potential. A weak tunable oscillator imposed parallel to the layer that rocks the potential landscape can pick up an incoming signal of interest as a result of resonance. To justify the model, we carried out analytic calculation as well as Monte Carlo simulation. The two approaches agree reasonably well for all the different parameter values we used.
Analytical simulations of the Fokas system; extension (2 + 1)-dimensional nonlinear Schrödinger equation
Authors: Khater Mostafa M. A.
Published: October 2021

This paper studies novel analytical solutions of the extended [Formula: see text]-dimensional nonlinear Schrödinger (NLS) equation which is also known with [Formula: see text]-dimensional complex Fokas ([Formula: see text]D–CF) system. Fokas derived this system in 1994 by using the inverse spectral method. This model is considered as an icon model for nonlinear pulse propagation in monomode optical fibers. Many novel computational solutions are constructed through two recent analytical schemes (Ansatz and Projective Riccati expansion (PRE) methods). These solutions are represented through sketches in 2D, 3D, and contour plots to demonstrate the dynamical behavior of pulse propagation in breather, rogue, periodic, lump, and solitary characteristics. The stability property of the obtained solutions is examined based on the Hamiltonian system’s properties. The obtained solutions are checked by putting them back into the original equation through Mathematica 12 software.
Novel Fractional-Order Current-Mode VCOs/SRCOs with All-Grounded-Passive-Elements
Authors: Subhadhra K. S. , Sharma R. K. , Gupta S. S.
Published: October 2021

Five new structures of linear fractional-order voltage-controlled oscillators (FO-VCOs) utilizing only Multiplication-Mode Current Conveyors (MMCCs) and canonic numbers of all grounded passive elements (AGPEs) are presented in this paper. The derivation procedure has been detailed along with the relevant nonideal analysis. The work also presents three fractional-order cases of the oscillators and brings out the effects of port nonidealities and port parasitics on the performance of presented FO-VCOs. The workability of all the five new FO-VCOs has been validated on PSPICE utilizing library files of AD844 and AD835 for realizing MMCC employed in the FO-VCOs. For all the three special fractional-order cases, the simulation results have been tabulated along with relevant MATLAB plots that facilitate comparison among oscillation parameters and the fractional order. The harmonic distortion figures have been found out by Fourier analysis. Experimental workability of a VCO, employing MMCC realized with AD835 and AD844 of our investigation is included to support hardware functionality.
On the periodic non-orientable 4-genus a knot
Authors: Grove Taran , Jabuka Stanislav
Published: October 2021

We show that the equivariant and non-equivariant non-orientable 4-genus of [Formula: see text]-periodic knots may differ, for any choice of [Formula: see text]. Similar results have previously been obtained for the smooth 4-genus and non-orientable 3-genus of a periodic knot. These stand in contrast to Edmonds’ acclaimed result by which the equivariant and non-equivariant Seifert genus of a periodic knot agree.
Nonlocality in quantum gravity and the breakdown of effective field theory
Authors: Valdés-Meller Nicolás
Published: October 2021

We argue that quantum gravity is nonlocal, first by recalling well-known arguments that support this idea and then by focusing on a point not usually emphasized: that making a conventional effective field theory (EFT) for quantum gravity is particularly difficult, and perhaps impossible in principle. This inability to realize an EFT comes down to the fact that gravity itself sets length scales for a problem: when integrating out degrees of freedom above some cutoff, the effective metric one uses will be different, which will itself re-define the cutoff. We also point out that even if the previous problem is fixed, naïvely applying EFT in gravity can lead to problems — we give a particular example in the case of black holes.
TIMING OPTIMIZATION OF HEAD AND NECK CT ANGIOGRAPHY VIA THE INVERSE PROBLEM ALGORITHM: in vivo SURVEY FOR 1001 PATIENTS IN 2020–2021
Authors: LIANG CHUN-CHIEH , PAN LUNG-FA , CHEN MING-HSIANG , DENG JIE , YANG DENG-HO , LIN CHIH-SHENG , PAN LUNG-KWANG
Published: October 2021

This study processed the recent in vivo survey results for over a thousand patients and optimized their neck and head CT angiography triggered timing (CTA-TT) via the inverse problem algorithm, which ensured the maximal ratio of both left and right arterial to upper sinuses (LRA/US). These results are instrumental in examining the ischemic stroke syndromes along the neck and head. These 1001 patients were randomly categorized into test surveyed (802 patients) and verification group (199 patients), then a six factors semi-empirical formula was constructed by the STATISTICA program. The six factors were assigned a patient’s biological data and preset of the CTA facility; namely Age, mean arterial pressure (MAP), heart rate (HR), contrast media dose (CMD), Pre (injected pressure of CMD), and body surface area (BSA). Each factor was normalized into dimensionless values and incorporated into the dataset matrix [Formula: see text] to analyze the coefficient matrix [Formula: see text]. The derived semi-empirical formula closely correlated with experimental data, according to the loss function [Formula: see text], correlation coefficient [Formula: see text], and variance of 0.8965. The formula verification for 199 more patients (verification group) yielded a correlation coefficient [Formula: see text]. Thus, it can be used for the CTA-TT estimation of patients without their preliminary tests, avoiding unnecessary irradiation. The estimated LRA/US was [Formula: see text] for the verification group in this study. A simplified three-factor formula, featuring only age, MAP, and BSA, was also proposed.
Einstein–Maxwell–Yang–Mills tetrad grand unification
Authors: Garat Alcides
Published: October 2021

In this short note, we will prove in a few steps that the new tetrads introduced previously in Einstein–Maxwell–Yang–Mills four-dimensional Lorentzian spacetimes where gravitational and Yang–Mills fields are present contain both the necessary information to provide the gravitational field and the necessary information to provide the electromagnetic and Yang–Mills fields as well. These new tools thus become grand unification objects.
Explicit Baker–Campbell–Hausdorff–Dynkin formula for spacetime via geometric algebra
Authors: Wilson Joseph , Visser Matt
Published: October 2021

We present a compact Baker–Campbell–Hausdorff–Dynkin formula for the composition of Lorentz transformations [Formula: see text] in the spin representation (a.k.a. Lorentz rotors) in terms of their generators [Formula: see text]: [Formula: see text] This formula is general to geometric algebras (a.k.a. real Clifford algebras) of dimension [Formula: see text], naturally generalizing Rodrigues’ formula for rotations in [Formula: see text]. In particular, it applies to Lorentz rotors within the framework of Hestenes’ spacetime algebra, and provides an efficient method for composing Lorentz generators. Computer implementations are possible with a complex [Formula: see text] matrix representation realized by the Pauli spin matrices. The formula is applied to the composition of relativistic [Formula: see text]-velocities yielding simple expressions for the resulting boost and the concomitant Wigner angle.
The long-time behaviors of non-autonomous stochastic Nicholson’s blowflies systems with patch structure and time delays
Authors: Zhao Dianli , Li Qiuya
Published: October 2021

In this paper, a class of non-autonomous stochastic Nicholson’s blowflies systems with patch structure and time delays is formulated and studied. By constructing suitable Lyapunov functions and using the stochastic technical, the pth moment boundedness and almost sure growth bounds are discussed, which reveal that solutions of the system do not exceed the time value [Formula: see text] and the sample Lyapunov exponent is no more than zero. Then, the system is proved to be exponentially stable (or extinct) if the production rate is less than the mortality rate, which provides an effective reference for the population control. Moreover, taking into account the specific form of time-varying coefficients, related results for several classical stochastic Nicholson’s blowflies systems are studied, and they show the significant improvement of this paper. Finally, numerical simulations for several specific examples are carried out to illustrate our theoretical conclusions.
Time-Invariance Coefficients Tests with the Adaptive Multi-Factor Model
Authors: Zhu Liao , Jarrow Robert A. , Wells Martin T.
Published: October 2021

This paper tests a multi-factor asset pricing model that does not assume that the return’s beta coefficients are constants. This is done by estimating the generalized arbitrage pricing theory (GAPT) using price differences. An implication of the GAPT is that when using price differences instead of returns, the beta coefficients are constant. We employ the adaptive multi-factor (AMF) model to test the GAPT utilizing a Groupwise Interpretable Basis Selection (GIBS) algorithm to identify the relevant factors from among all traded exchange-traded funds. We compare the performance of the AMF model with the Fama–French 5-factor (FF5) model. For nearly all time periods less than six years, the beta coefficients are time-invariant for the AMF model, but not for the FF5 model. This implies that the AMF model with a rolling window (such as five years) is more consistent with realized asset returns than is the FF5 model.
The multidisciplinary management of gastric cancer: Experience from a tertiary comprehensive hospital in Shanghai, China
Authors: Cai Hui , Zhang Mo , Fu Zhongxing , Nie Mingming , Yin Kai , Du Yan
Published: October 2021

Gastric cancer is a heterogeneous disease which requires a multimodal approach of management. The Department of Gastrointestinal Surgery at Changhai Hospital, a tertiary hospital in Shanghai, established the gastric cancer multidisciplinary team (MDT) clinic based on the guidance of MDT culture in the year of 2017. Our MDT discussion followed a weekly consultation model, with the full-board discussion held once a month, and mini-board communication and discussion made once a week. The stages of MDT management are: pre-operative treatment plan and preparation, post-operative treatment plan, and follow-up treatment and evaluation. As of March 2021, a total of 296 patients visited the MDT clinic. Majority of the patients were gastric carcinoma patients (273/296, 92.2%). Here, we shared our gastric cancer MDT experiences and summarized our strengths and proposed directions for improvement.
The Complexity of the Ideal Membership Problem for Constrained Problems Over the Boolean Domain
Authors: Mastrolilli Monaldo
Published: October 2021

Given an ideal
I
and a polynomial
f
the Ideal Membership Problem (IMP) is to test if
f ϵ I
. This problem is a fundamental algorithmic problem with important applications and notoriously intractable.

We study the complexity of the IMP for combinatorial ideals that arise from constrained problems over the Boolean domain. As our main result, we identify the borderline of tractability. By using Gröbner bases techniques, we extend Schaefer’s dichotomy theorem [STOC, 1978] which classifies all Constraint Satisfaction Problems (CSPs) over the Boolean domain to be either in P or NP-hard. Moreover, our result implies necessary and sufficient conditions for the efficient computation of Theta Body Semi-Definite Programming (SDP) relaxations, identifying therefore the borderline of tractability for constraint language problems.

This article is motivated by the pursuit of understanding the recently raised issue of bit complexity of Sum-of-Squares (SoS) proofs [O’Donnell, ITCS, 2017]. Raghavendra and Weitz [ICALP, 2017] show how the IMP tractability for combinatorial ideals implies bounded coefficients in SoS proofs.
Privacy and Confidentiality in Process Mining: Threats and Research Challenges
Authors: Elkoumy Gamal , Fahrenkrog-Petersen Stephan A. , Sani Mohammadreza Fani , Koschmider Agnes , Mannhardt Felix , Von Voigt Saskia Nuñez , Rafiei Majid , Waldthausen Leopold Von
Published: October 2021

Privacy and confidentiality are very important prerequisites for applying process mining to comply with regulations and keep company secrets. This article provides a foundation for future research on privacy-preserving and confidential process mining techniques. Main threats are identified and related to a motivation application scenario in a hospital context as well as to the current body of work on privacy and confidentiality in process mining. A newly developed conceptual model structures the discussion that existing techniques leave room for improvement. This results in a number of important research challenges that should be addressed by future process mining research.
Distance Based Pattern Driven Mining for Outlier Detection in High Dimensional Big Dataset
Authors: Kumar Ankit , Kumar Abhishek , Bashir Ali Kashif , Rashid Mamoon , Kumar V. D. Ambeth , Kharel Rupak
Published: October 2021

Detection of outliers or anomalies is one of the vital issues in pattern-driven data mining. Outlier detection detects the inconsistent behavior of individual objects. It is an important sector in the data mining field with several different applications such as detecting credit card fraud, hacking discovery and discovering criminal activities. It is necessary to develop tools used to uncover the critical information established in the extensive data. This paper investigated a novel method for detecting cluster outliers in a multidimensional dataset, capable of identifying the clusters and outliers for datasets containing noise. The proposed method can detect the groups and outliers left by the clustering process, like instant irregular sets of clusters (C) and outliers (O), to boost the results. The results obtained after applying the algorithm to the dataset improved in terms of several parameters. For the comparative analysis, the accurate average value and the recall value parameters are computed. The accurate average value is 74.05% of the existing COID algorithm, and our proposed algorithm has 77.21%. The average recall value is 81.19% and 89.51% of the existing and proposed algorithm, which shows that the proposed work efficiency is better than the existing COID algorithm.