bluuebunny/crossref_metadata_2025 huggingface dataset:
P.124 Baseline Assessment of Attention and Executive Function Deficits in
Children with Neurodevelopmental Disorders: Data from a Speciality Attention
Clinic
Authors: Wiley B , Ghanim F , Taylor K , Murias K
Published: January 2022

Background: Attention and executive function (EF)
deficits in children negatively impact academics, social interactions, and
overall quality of life. Children with other brain-based disorders are at
high risk for attention and EF concerns, but the effects of these
impairments are not well studied in the literature. The Complex Attention
and Executive Function Clinic at the Alberta Children’s Hospital collected
baseline data on patients referred for concerns of attention deficits
co-occurring with diagnosed neurologic illness/injury, or neurodevelopmental
disorder (NDD). Methods: The Behaviour Rating
Inventory of Executive Function (BRIEF-2), Behaviour Assessment System for
Children (BASC-3), Parenting Stress Index (PSI-4) and medical and past
treatment information were collected on initial clinic visit for patients
aged 5-15 years. Results: BRIEF-2 Global Executive
Composite demonstrated 88.9% of children had clinically elevated scores.
Clinically significant scores were observed in 55.5% for BASC-3 Adaptive
Skills index and 40% of parents in PSI-4 Total Stress scores.
Conclusions: Children with neurologic
illness/NDDs are at high risk of clinical impairments in attention and EF.
In children referred for attention and behavioural regulation, there is
clinically significant increased reporting of executive function impairment
out of proportion to other behavioural difficulties. The clinic aims to
improve overall functioning through treatment of unmanaged attention and EF
deficits.
P.131 Outcomes of Nusinersen in adult and pediatric cohorts of spinal
muscular amyotrophy after two years of usage at the CHU de Québec-Université
Laval
Authors: Michel M , Chrestian N , Demers I , Déry N , Dionne A , Jobin C , Lepage K , Paquin V , Rodrigue X
Published: January 2022

Background: Nusinersen is approved for spinal
muscular amyotrophy type I,II,III and is available for adult and pediatric
populations since January 2019 at the CHU de Québec-UL.
Methods: Patients who received at least one dose
of nusinersen between January 2019 and March 2021 were included. Required
information was gathered from patients’ charts.
Results: Ten adults (70 injections) and 23
infants and children (202 injections) were included. No child but two adults
stopped the therapy for personal reasons. Tests were performed at 0, 6, 18,
24 months when possible to assess efficacy, tolerability and quality of life
perception (Table 1). Preliminary data shows stabilization or improvement
for many tests. Conclusions: Nusinersen is well
tolerated. Favorable effects were observed in both populations. A monitoring
is still imperative for an objective assessment and for evaluation of the
most relevant tests. Long term benefits remain to be demonstrated but
results are encouraging.
P.146 Non-contrast CT markers of intracerebral hemorrhage expansion: a
predictive accuracy and reliability study
Authors: Nehme A , Panzini M , Ducroux C , Maallah MT , Bard C , Bereznyakova O , Boisseau W , Deschaintre Y , Diestro JD , Jacquin G , Nelson K , Padilha I , Poppe AY , Rioux B , Roy D , Touma L , Weill A , Gioia LC , Létourneau-Guillon L
Published: January 2022

Background: We evaluated (1) the predictive
accuracy and (2) multi-observer reliability of non-contrast CT markers of
hematoma expansion (HE). Methods: In 124 patients
with spontaneous intracerebral hemorrhage, two investigators documented the
presence of six density (Barras density, hypodensity, black hole, swirl,
blend, fluid level) and three shape (Barras shape, island, satellite)
expansion markers, with discrepancies resolved by a third rater. We defined
HE as any one of (1) >6 mL absolute or >33% relative growth of the
intraparenchymal hematoma or (2) an absolute growth of >1 mL or new
development of intraventricular hematoma. A subsample of 60 patients was
used for the inter-observer reliability study in 13 raters. Seven raters
participated in the intra-rater study. Results: The
sensitivity of markers for HE varied between 4% (fluid level) and 78%
(satellite), while specificity ranged from 37% (swirl) to 97% (black hole).
Almost perfect inter-rater agreement was observed for the swirl (0.89) and
fluid level (0.83) markers, while hypodensity (0.65) showed substantial
agreement. Only the blend and fluid level markers achieved substantial
intra-rater agreement (> 0.6) in all raters.
Conclusions: Non-contrast CT markers of HE showed
lower reliability and predictive accuracy than previously reported. Future
studies should address means to improve NCCT-based HE prediction.
P.153 Profiles and Outcomes of Workers’ Compensation Patients Undergoing
Spinal Cord Stimulation for Persistent Post Surgical Pain
Authors: Varshney V , Sahjpaul R , Osborn J
Published: January 2022

Background: The challenges of chronic pain
management, and resulting poorer outcomes, in workers’ compensation (WCB)
patients has been well established. Spinal cord stimulation (SCS) has been
used for the management of low back and radicular neuropathic pain with
varying effectiveness and it’s efficacy in the WCB population has been
challenged. We sought to examine our experience using SCS in WCB compared to
non WCB patients. Methods: A retrospective analysis
of 71 WCB patients assessed and treated at the St Pauls Hospital
neuromodulation program between 2016-2021 was performed. This group was
compared to a cohort on non WCB patients in terms of the likelhood of being
offered a trial, proceeding with trial if offered, and the likelhood of a
successful trial proceeding to implant. Results:
Compared to non WCB, the WCB patients were more likely to be offered a trial
(86% vs 77%) and more likely to proceed with a trial if offered (82% vs
71%). Trial to implant ratios were similar in both WCB and non WCB patients
(78% vs 77%). Conclusions: WCB patients were more
likely to be offered a SCS trial and more likely to accept if offered,
compared to non-WCB patients. However, both groups were similar in trial to
implant probability.
P.158 Feeling Green
Authors: Ghare A , Langdon K , Andrade A , Kiwan R , Ranger A , Hammond R
Published: January 2022

Background: Myeloid sarcoma (MS) is a rare solid
tumour made of myeloblasts or immature myeloid cells in an extramedullary
site or in bone, associated with systemic hematologic neoplasms. When they
occur in the brain parenchyma, they can often be misdiagnosed.
Methods: The authors report a case of a 4-year
old boy 6 months out of remission from AML, presenting with a short history
of headaches and vomiting, and found to have a heterogenous
contrast-enhancing lesion in the right cerebellar hemisphere, with
differential diagnosis of myeloid sarcoma, astrocytoma, medulloblastoma and
ATRT. Preliminary diagnosis was made flow cytometry from an intraoperative
biopsy. The patient had a long course of chemotherapy and radiation, but
eventually died from the systemic burden of his AML.
Results: The authors present a literature review
on 178 published cases of CNS myeloid sarcomas, and their radiological
presentation and the basis of immunohistochemical and pathological diagnosis
is discussed. Conclusions: Diagnosis rests on a
combination of immunohistochemistry and histopathology of biopsied tissue.
Surgical resection is controversial, especially given the efficacy of
chemotherapy and radiation, and prognosis remains unclear. As with all
uncommon and rare clinical entities, further investigation is warranted to
determine prognosis and optimal management of CNS myeloid sarcomas.
P.178 Neurosurgical Faculty Expectations of Entrustable Professional
Activities Evaluations
Authors: Rabski J , Cusimano MD
Published: January 2022

Background: Competence by Design (CBD), a new
outcomes-based approach to medical education, has been recently introduced
into neurosurgical programs across Canada. A cornerstone of this educational
paradigm shift requires evaluation of residents’ performances of entrustable
professional activities (EPAs). This study aimed to define Faculty
expectations and markers of competence for resident EPA performances.
Methods: Canada-wide survey of neurosurgical
Faculty (NSF) with a 55-item online questionnaire referencing 15/45
available core neurosurgery EPAs. Results: Of the 52
respondents, majority believed that being able to perform safely (98%),
effectively (92%) and independently (90%) and being able to adapt to
contextual complexities of the case (88%) and unexpected events (88%)
represented necessary qualities for demonstrating competence achievement of
an EPA. Performing efficiently, without supervision and responding to rare
events were all considered less important. On average, NSF believed that at
least five separate assessments involving two or more different assessors
were necessary for documenting competence achievement of each EPA.
Proportion believing EPAs were representative of general neurosurgery
competences varied significantly across all EPAs (p<0.00001) with >25%
believing 5/15 EPAs required fellowship training.
Conclusions: This study defined expectations and
indicators of competent surgical performance and revealed a significant
debate regarding perceived appropriateness of current EPAs for general
neurosurgical training.
P.180 What do patients expect of a competent neurosurgeon?
Authors: Rabski J , Baba A , Bannon L , Cusimano MD
Published: January 2022

Background: To improve accountability and reflect
patient and societal needs, the Royal College of Physicians and Surgeons of
Canada proposed Competence by Design (CBD) for all residency programs. This
study compares neurosurgical patient values and expectations of their
neurosurgeon to resident competences proposed by CBD curriculum.
Methods: Semi-structured interviews of 30
neurosurgical patients and family members were recorded, transcribed and
analyzed for themes. Results: Of the first 13
interviews (8 males, 5 females; median age 54), 10 had English as a first
language, all completed post-secondary education, and 8 had a brain tumor.
In addition to expecting excellent surgical skills and comprehensive medical
knowledge, participants expected “good” neurosurgeons to be human
(compassionate, empathetic, no ego), transparent communicators, accountable,
passionate, collaborative, emotionally composed and highly intuitive.
However, there were marked differences in minimum set of competencies
required and the expectations of the thresholds to determine competence for
neurosurgeons. Conclusions: Patient perspectives show
commonalities and marked differences of the expected competencies compared
to CBD and significant variability of the thresholds of competence. Further
investigations should explore these themes in other specialties. The
existing CBD curriculum will need to expand its framework to include
humanistic values to improve public perceptions of competence.
P.184 Off-road vehicle fatalities and alcohol in patients with major
traumatic brain injury: the risk of impaired driving
Authors: Walling S , Kureshi N , Clarke DB , Erdogan M , Green RS
Published: January 2022

Background: Intoxicated patients injured in off
road vehicle (ORV) crashes have higher rates of traumatic brain injury (TBI)
and intensive care unit (ICU) admission, as well as prolonged ICU length of
stay. This study evaluated the impact of alcohol intoxication on mortality
among major TBI patients injured in off-road vehicle crashes.
Methods: A retrospective analysis (2002-2014) of
off-road vehicle injuries in Nova Scotia resulting in major TBI was
performed. ORVs included ATVs, snowmobiles, and dirt bikes. A logistic
regression model was constructed to test for in-hospital mortality and
adjusted for age, Abbreviated Injury Scale (AIS) Head, Injury Severity
Score, and blood alcohol concentration (BAC).
Results: There were 176 drivers and passengers of
off-road vehicles. Overall mortality was 28%. BAC testing was performed in
61% patients; 85% of pre-hospital deaths were BAC positive (mean BAC=31 ±
17.39 mmol/L) and 70% in-hospital deaths were BAC positive (mean BAC=26 ±
23.12 mmol/L). After adjusting for confounders, high injury severity and
intoxication increased the likelihood of in-hospital mortality.
Conclusions: These findings demonstrate that
alcohol intoxication is a significant risk factor for mortality among
off-road vehicle collisions; for every mmol/L change in BAC, there was a 10%
increase in the chance of in-hospital mortality.
P.189 Unruptured Posterior Cerebral Artery aneurysm causing temporal lobe
epilepsy
Authors: Fatehi Hassanabad M , Redekop G , Yefet LS
Published: January 2022

Background: Cerebral aneurysms are an unusal
cause of epilepsy. To date, several groups have reported temporal lobe
seizures caused by aneurysms projecting into the parahippocampal gyrus.
Given the low incidence of posterior cerebral artery aneurysms, they are a
very rare cause of temporal lobe seizures. Methods:
Here, we report a rare case of temporal lobe epilepsy caused by an
unruptured aneurysm. We also present a review of the literature yielding two
similar cases. Results: A previosuly well 56 year old
male presented to a neurologist with symptoms consistent with temporal lobe
epilepsy. He was started on carbamzepine and underwent imaging and
neuropsychological assessments. An MRI suggested the existance of a 7mm
posterior cerebral artery aneurysm arising from the P2 segment of the
posterior cerebral artery and projecting into the parahippocampal gyrus.
This was also confirmed with CT angiography and the patient elected to have
the aneurysm clipped. Conclusions: Temporal lobe
epilepsy is an uncommon presentation for unruptured cerebral aneurysms. We
report a rare case wherein a laterally pointing PCA aneurysm was buried in
the posterior parahippocampal gyrus. This aneurysm had caused perifocal
gliosis leading to stereotyped seizures. Post-operatively, the patient has
been seizure free.
P.192 Arterial Hemodynamics and the Clinical Presentation of Cerebral
Arteriovenous Malformations
Authors: Lownie S , Chalil A
Published: January 2022

Background: Arterial Hemodynamics have been
implicated in hemorrhage from cerebral arteriovenous malformations (AVMs).
The correlation between hemodynamic characteristics and the tendency of AVMs
to rupture has been explored in the past, and various theories have been
proposed to explain the clinical presentation of AVMs as a hemorrhage vs.
seizure. Methods: We monitored feeder artery
pressures in 45 patients with AVMS (16 presenting with hemorrhage, 29
without) during super selective angiography and AVM embolization.
Results: Mean feeder artery pressure (FP) was
found to be 49mm Hg. The mean FP in patients presenting with hemorrhage was
somewhat higher than in those without hemorrhage, but the difference was not
statistically significant (53.8 mm Hg vs 47.0 mm Hg, p=0.13). Systemic mean
pressure was found to correlate with AVM size (r=-0.31, p=0.037).
Significant predictors of feeder artery pressure were systemic pressure, AVM
size, and the distance of microcatheter from the circle of Willis.
Meanwhile, the presence or absence of venous outflow stenosis and the
position of the AVM nidus (superficial or deep to the cortical surface) were
the most significant predictors of AVM hemorrhage vs seizures.
Conclusions: Anatomic factors may be more
important than arterial hemodynamic factors in determining the clinical
presentation of cerebral AVMs.
P.196 Antiplatelet, anticoagulant, or endovascular treatment for stroke
prevention in blunt cerebrovascular injury: Retrospective review, systematic
review and meta-analysis
Authors: Ku JC , Priola SM , Taslimi S , Mathieu F , Pasarikovski CR , Kumar A , Machnowska M , Nathens A , Yang V , da Costa L
Published: January 2022

Background: Ischemic stroke occurs following
trauma-related blunt cerebrovascular injury (BCVI) in up to 20% of cases.
Preventative treatment includes antiplatelets, anticoagulants, and/or
endovascular treatment (ET), but the optimal choice remains unclear. The
objective of this study was to compare the ischemic stroke rate between
these three treatments. Methods: Following PRISMA
guidelines, we queried the OVID Medline, Embase, Web of Science, and
Cochrane Library databases from September 2019 to inception to identify
studies reporting treatment-stratified outcomes in BCVI patients.
Meta-analysis was performed to compare outcomes between the treatment
groups, using odds ratios. Retrospective review of our institutional
experience with BCVI outcomes was performed and added to the meta-analysis.
Results: Analysis of seven comparative studies of
antiplatelets (n=334) versus anticoagulation (n=325) found no significant
difference in ischemic stroke rate (OR 1.27, 95%CI 0.40-3.99), but a
decrease in hemorrhagic complications (OR 0.38, 95%CI 0.15-1.00). Analysis
of seven comparative studies of antiplatelets/anticoagulants (n=805) versus
ET (n=235) also found no significant difference in stroke rate (OR 0.71,
95%CI 0.35-1.42). Conclusions: Antiplatelets and
anticoagulants were similarly effective in reducing ischemic stroke risk in
BCVI, but antiplatelets were better tolerated in this trauma population. The
addition of endovascular treatment did not further reduce stroke risk
compared to antiplatelets or anticoagulants alone.
P.225 Factors Contributing to Prolonged Length of Stay in Adults
Undergoing Spine Surgery: Results from a Quaternary Spinal Care
Center
Authors: Hindi MN , Dandurand C , Paquette S , Kwon B , Ailon T , Dvorak M , Dea N , Charest-Morin R , Fisher C , Boyd M , Street J
Published: January 2022

Background: Prolonged length of stay (LOS) is
associated with increased resource utilization and worse outcomes. The goal
of this study is identifying patient, surgical and systemic factors
associated with prolonged LOS overall and per diagnostic category for adults
admitted to a quaternary spinal care center. Methods:
We performed a retrospective analysis on 13,493 admissions from 2006 to
2019. Factors analyzed included patient age, sex, emergency vs elective
admission, diagnostic category (degenerative, deformity, oncology, trauma),
presence of neurological deficits in trauma patients, ASIA score, operative
management and duration, blood loss, and adverse events (AEs). Univariate
and multivariate analyses determined factors associated with prolonged LOS.
Results: Overall mean LOS (±SD) was 15.80
(±34.03) days. Through multivariate analyses, predictors of prolonged LOS
were advanced age (p<0.001), emergency admission (p<0.001), advanced
ASIA score (p<0.001), operative management (p=0.043), and presence of AEs
(p<0.001), including SSI (p=0.001), other infections (systemic and UTI)
(p<0.001), delirium (p=0.006), and pneumonia (p<0.001). The effects of
age, emergency admission, and AEs on LOS differed by diagnostic category.
Conclusions: Understanding patient and disease
factors that affect LOS provides opportunities for QI intervention and
allows for an informed preoperative discussion with patients. Future
interventions can be targeted to maximize patient outcomes, optimize care
quality, and decrease costs.
P.228 Pre-operative Surrogates Markers of Frailty and Metastatic Spine
Disease: Systematic Review
Authors: Touchette CJ , MacLean MA , Brunette-Clement T , Abduljabba FH , Weber MH , Fourney DR
Published: January 2022

Background: Despite the inherent importance of
physical reserve and ability to tolerate surgery, pre-operative
patient-specific surrogate markers of frailty that may improve accuracy of
outcome prognostication following surgery for SMD are not well
described. Methods: A systematic review was
performed according to Preferred Reporting Items for Systematic Reviews and
Meta-Analyses (PRISMA) guidelines. MEDLINE, Scopus, EMBASE, Cochrane
Registry of Controlled Trials, CINAHL, and Web of Science were searched.
Quality of evidence was scored using the Oxford CEBM Scoring Tool.
Results: Forty studies accounted for 8,364
patients. Surgical indications included neurological dysfunction,
intractable pain, and spinal instability. Tumor histology varied across and
within studies. Age, gender, performance status, neurologic function,
comorbidities, and biochemical abnormalities were the most frequently
analyzed pre-operative surrogate markers of frailty. The most commonly
assessed outcomes were overall and progression-free survival; few studies
examined health-related quality of life, peri-operative adverse events, and
post-operative complications. Conclusions: This study
highlights the need for objective measures of frailty in order to improve
risk stratification and outcome prognostication among patients receiving
surgery for metastatic spinal disease. Future studies should address
identified knowledge gaps pertaining to peri-operative adverse events,
post-operative complications, and health-related quality of life
outcomes.
Robust design using multiobjective optimisation and artificial neural networks with application to a heat pump radial compressor
Authors: Massoudi Soheyl , Picard Cyril , Schiffmann Jürg
Published: January 2022

Although robustness is an important consideration to guarantee the performance of designs under deviation, systems are often engineered by evaluating their performance exclusively at nominal conditions. Robustness is sometimes evaluated a posteriori through a sensitivity analysis, which does not guarantee optimality in terms of robustness. This article introduces an automated design framework based on multiobjective optimisation to evaluate robustness as an additional competing objective. Robustness is computed as a sampled hypervolume of imposed geometrical and operational deviations from the nominal point. In order to address the high number of additional evaluations needed to compute robustness, artificial neutral networks are used to generate fast and accurate surrogates of high-fidelity models. The identification of their hyperparameters is formulated as an optimisation problem. In the frame of a case study, the developed methodology was applied to the design of a small-scale turbocompressor. Robustness was included as an objective to be maximised alongside nominal efficiency and mass-flow range between surge and choke. An experimentally validated 1D radial turbocompressor meanline model was used to generate the training data. The optimisation results suggest a clear competition between efficiency, range and robustness, while the use of neural networks led to a speed-up by four orders of magnitude compared to the 1D code.
Robust design of complex socio-technical systems against seasonal effects: a network motif-based approach
Authors: Xiao Yinshuang , Sha Zhenghui
Published: January 2022

Seasonal effects can significantly impact the robustness of socio-technical systems (STS) to demand fluctuations. There is an increasing need to develop novel design approaches that can support capacity planning decisions for enhancing the robustness of STS against seasonal effects. This paper proposes a new network motif-based approach to supporting capacity planning in STS for an improved seasonal robustness. Network motifs are underlying nonrandom subgraphs within a complex network. In this approach, we introduce three motif-based metrics for system performance evaluation and capacity planning decision-making. The first one is the imbalance score of a motif (e.g., a local service network), the second one is the measurement of a motif’s seasonal robustness, and the third one is a capacity planning decision criterion. Based on these three metrics, we validate that the sensitivity of STS performance against seasonal effects is highly correlated with the imbalanced capacity between service nodes in an STS. Correspondingly, we formulate a design optimisation problem to improve the robustness of STS by rebalancing the resources at critical service nodes. To demonstrate the utility of the approach, a case study on Divvy bike-sharing system in Chicago is conducted. With a focus on the size-3 motifs (a subgraph consisting three docked stations), we find that there is a significant correlation between the difference of the number of docks among the stations in a motif and the return/rental performance of such a motif against seasonal changes. Guided by this finding, our design approach can successfully balance out the number of docks between those stations that have caused the most severe seasonal perturbations. The results also imply that the network motifs can be an effective local structural representation in support of STS robust design. Our approach can be generally applied in other STS where the system performances are significantly impacted by seasonal changes, for example, supply chain networks, transportation systems and power grids.
Assessing the confidence, knowledge and learning preferences of healthcare workers regarding personal protective equipment use during the coronavirus disease 2019 (COVID-19) pandemic
Authors: Brown Rachel , Brown Amanda M. , Markman Sharon , Mian Rukhshan , Arora Vineet M. , Umscheid Craig A.
Published: January 2022

We surveyed healthcare workers at an urban academic hospital in the United States about their confidence in and knowledge of appropriate personal protective equipment use during the coronavirus disease 2019 (COVID-19) pandemic. Among 461 respondents, most were confident and knowledgeable about use. Prescribers or nurses and those extremely confident about use were also the most knowledgeable.
Water–propylene glycol sessile droplet shapes and migration: Marangoni mixing and separation of scales
Authors: Charlier J. , Rednikov A.Y. , Dehaeck S. , Colinet P. , Terwagne D.
Published: January 2022

New light is shed on morphological features of water–propylene glycol sessile droplets evaporating into ambient air at not too high relative humidity. Such droplets adopt a Marangoni-contracted shape even on perfectly wetting substrates, an effect well known since Cira et al. (Nature, 519, 2015). We here highlight a strong separation of scales normally occurring for such droplets. Namely, there is a narrow high-curvature zone localized at the foot of the droplet, where the apparent contact angle is formed, while the core of the droplet merely adheres to the classical (capillary–gravity) static shape. Experimentally, we rely upon interferometry to discern such fine key details. We detect a maximum of the droplet slope profile in the foot region, which amounts to the apparent contact angle. Theoretically, a local description of the foot region is devised. We indicate a crucial role of convective mixing by the solutal Marangoni flow, here accounted for by the Taylor dispersion, which proves to underlie the separation of scales and ensure self-consistency of the local model. Migration of such droplets in a humidity gradient is also approached within the same experimental and theoretical framework. It is considered that the resulting back–front asymmetry of the apparent contact angles drives the motion similarly to a wettability gradient, although the drag (‘Cox–Voinov’) factor is here found to be different. The predictions, comparing well with the measurements (our own and from the literature), are based on rigorous models, isothermal and as reduced as possible, without any fitting parameters or microphysics effects.
Experimental study on radial gravity currents flowing in a vegetated channel
Authors: Petrolo D. , Ungarish M. , Chiapponi L. , Longo S.
Published: January 2022

We present an experimental study of gravity currents in a cylindrical geometry, in the presence of vegetation. Forty tests were performed with a brine advancing in a fresh water ambient fluid, in lock release, and with a constant and time-varying flow rate. The tank is a circular sector of angle

$30^\circ$

with radius equal to 180 cm. Two different densities of the vegetation were simulated by vertical plastic rods with diameter

$D=1.6\ \textrm{cm}$

. We marked the height of the current as a function of radius and time and the position of the front as a function of time. The results indicate a self-similar structure, with lateral profiles that after an initial adjustment collapse to a single curve in scaled variables. The propagation of the front is well described by a power law function of time. The existence of self-similarity on an experimental basis corroborates a simple theoretical model with the following assumptions: (i) the dominant balance is between buoyancy and drag, parameterized by a power law of the current velocity

$\sim |u|^{\lambda-1}u$

; (ii) the current advances in shallow-water conditions; and (iii) ambient-fluid dynamics is negligible. In order to evaluate the value of

${\lambda}$

(the only tuning parameter of the theoretical model), we performed two additional series of measurements. We found that

$\lambda$

increased from 1 to 2 while the Reynolds number increased from 100 to approximately

$6\times10^3$

, and the drag coefficient and the transition from

$\lambda=1$

to

$\lambda=2$

are quantitatively affected by D, but the structure of the model is not.
On locally embedded two-scale solution for wall-bounded turbulent flows
Authors: Chen C. , He L.
Published: January 2022

Recent findings on wall-bounded turbulence have prompted a new impetus for modelling development to capture and resolve the Reynolds-number-dependent influence of outer flow on near-wall turbulence in terms of the ‘foot-printing’ of the large-scale coherent structures and the scale-interaction associated ‘modulation’. We develop a two-scale method to couple a locally embedded near-wall fine-mesh direct numerical simulation (DNS) block with a global coarser mesh domain. The influence of the large-scale structures on the local fine-mesh block is captured by a scale-dependent coarse–fine domain interface treatment. The coarse-mesh resolved disturbances are directly exchanged across the interface, while only the fine-mesh resolved fluctuations around the coarse-mesh resolved variables are subject to periodic conditions in the streamwise and spanwise directions. The global near-wall coarse-mesh region outside the local fine-mesh block is governed by the augmented flow governing equations with forcing source terms generated by upscaling the space–time-averaged fine-mesh solution. The validity and effectiveness of the method are examined for canonical incompressible channel flows at several Reynolds numbers. The mean statistics and energy spectra are in good agreement with the corresponding full DNS data. The results clearly illustrate the ‘foot-printing’ and ‘modulation’ in the local fine-mesh block. Noteworthy also is that neither spectral-gap nor scale-separation is assumed, and a smooth overlap between the global-domain and the local-domain energy spectra is observed. It is shown that the mesh-count scaling with Reynolds number is potentially reduced from

$O(R{e^2})$

for the conventional fully wall-resolved large-eddy simulation (LES) to

$O(Re)$

for the present locally embedded two-scale LES.
A weakly nonlinear framework to study shock–vorticity interaction
Authors: Thakare Pranav , Nair Vineeth , Sinha Krishnendu
Published: January 2022

Linear interaction analysis (LIA) is routinely used to study the shock–turbulence interaction in supersonic and hypersonic flows. It is based on the inviscid interaction of elementary Kovásznay modes with a shock discontinuity. LIA neglects nonlinear effects, and hence it is limited to small-amplitude disturbances. In this work, we extend the LIA framework to study the fundamental interaction of a two-dimensional vorticity wave with a normal shock. The predictions from a weakly nonlinear framework are compared with high-order accurate numerical simulations over a range of wave amplitudes (

$\epsilon$

), incidence angles (

$\alpha$

) and shock-upstream Mach numbers (

$M_1$

). It is found that the nonlinear generation of vorticity at the shock has a significant contribution from the intermodal interaction between vorticity and acoustic waves. Vorticity generation is also strongly influenced by the curvature of the normal shock wave, especially for high incidence angles. Further, the weakly nonlinear analysis is able to predict the correct scaling of the nonlinear effects observed in the numerical simulations. The analysis also predicts a Mach number dependent limit for the validity of LIA in terms of the maximum possible amplitude of the upstream vorticity wave.
Impact of osmotic pressure on the stability of Taylor vortices
Authors: Ben Dhia Rouae , Tilton Nils , Martinand Denis
Published: January 2022

We use linear stability analysis and direct numerical simulations to investigate the coupling between centrifugal instabilities, solute transport and osmotic pressure in a Taylor–Couette configuration that models rotating dynamic filtration devices. The geometry consists of a Taylor–Couette cell with a superimposed radial throughflow of solvent across two semi-permeable cylinders. Both cylinders totally reject the solute, inducing the build-up of a concentration boundary layer. The solute retroacts on the velocity field via the osmotic pressure associated with the concentration differences across the semi-permeable cylinders. Our results show that the presence of osmotic pressure strongly alters the dynamics of the centrifugal instabilities and substantially reduces the critical conditions above which Taylor vortices are observed. It is also found that this enhancement of the hydrodynamic instabilities eventually plateaus as the osmotic pressure is further increased. We propose a mechanism to explain how osmosis and instabilities cooperate and develop an analytical criterion to bound the parameter range for which osmosis fosters the hydrodynamic instabilities.
Comprehensive simulations of boiling with a resolved microlayer: validation and sensitivity study
Authors: Bureš Lubomír , Sato Yohei
Published: January 2022

The dynamics of the microlayer beneath a growing bubble in nucleate boiling significantly impacts the heat-transfer characteristics of the process. The minute thickness of the microlayer motivates the use of direct numerical simulation (DNS) to model its behaviour if empirical models are to be avoided. In this work, we develop a computational strategy for utilising DNS to model nucleate boiling by resolving explicitly the microlayer, directly coupling, in a stable manner, the mass, momentum and energy conservation equations with the conjugate heat transfer between the solid and fluid domains. To this end, closure models for the treatment of interfacial heat transfer and the dynamic contact angle are introduced and substantiated. The computational procedure is validated against relevant experimental data recently measured at the Massachusetts Institute of Technology; it is shown that the main observed growth features and surface heat-transfer characteristics are well reproduced using our model. We go on to perform a sensitivity study of the dependence of the initial microlayer thickness distribution on the applied superheat and fluid properties. The results indicate that an equation derived from lubrication theory captures the observed trends well. Finally, a first demonstration of DNS of boiling with an explicitly resolved microlayer in three-dimensional Cartesian coordinates is presented in one of the appendices.
Stable channel flow with spanwise heterogeneous surface temperature
Authors: Bon T. , Meyers J.
Published: January 2022

Recent studies have demonstrated that large secondary motions are excited by surface roughness with dominant spanwise length scales of the order of the flow's outer length scale. Inspired by this, we explore the effect of spanwise heterogeneous surface temperature in weakly to strongly stratified closed channel flow (at$Ri_\tau =120$, 960;$Re_\tau = 180$, 550) with direct numerical simulations. The configuration consists of equally sized strips of high and low temperature at the lower and upper boundaries, while an overall stable stratification is induced by imposing an average temperature difference between the top and bottom. We consider the influence of the width of the strips (${\rm \pi} /8 \leq \lambda /h \leq 4{\rm \pi} $), Reynolds number, stability and upper boundary condition on the mean flow structure, skin friction and heat transfer. Results indicate that secondary flows are excited, with alternating high- and low-momentum pathways and vortices, similar to the patterns induced by spanwise heterogeneous surface roughness. We find that the impact of the surface heterogeneity on the outer layer depends strongly on the spanwise heterogeneity length scale of the surface temperature. Comparison to stable channel flow with uniform temperature reveals that the heterogeneous surface temperature increases the global friction coefficient and reduces the global Nusselt number in most cases. However, for the high-Reynolds cases with$\lambda /h \geq {\rm \pi} /2$, we find a reduction of the friction coefficient. At stronger stability, the vertical extent of the vortices is reduced and the impact of the heterogeneous temperature on momentum and heat transfer is smaller.
The emission properties, structure and stability of ionic liquid menisci undergoing electrically assisted ion evaporation
Authors: Gallud Ximo , Lozano Paulo C.
Published: January 2022

The properties and structure of electrically stressed ionic liquid menisci experiencing ion evaporation are simulated using an electrohydrodynamic model with field-enhanced thermionic emission in steady state for an axially symmetric geometry. Solutions are explored as a function of the external background field, meniscus dimension, hydraulic impedance and liquid temperature. Statically stable solutions for emitting menisci are found to be constrained to a set of conditions: a minimum hydraulic impedance, a maximum current output and a narrow range of background fields that maximizes at menisci sizes of 0.5–3

${\rm \mu}{\rm m}$

in radius. Static stability is lost when the electric field adjacent to the electrode that holds the meniscus corresponds to an electric pressure that exceeds twice the surface tension stress of a sphere of the same size as the meniscus. Preliminary investigations suggest this limit to be universal, therefore, independent of most ionic liquid properties, reservoir pressure, hydraulic impedance or temperature and could explain the experimentally observed bifurcation of a steady ion source into two or more emission sites. Ohmic heating near the emission region increases the liquid temperature, which is found to be important to accurately describe stability boundaries. Temperature increase does not affect the current output when the hydraulic impedance is constant. This phenomenon is thought to be due to an improved interface charge relaxation enhanced by the higher electrical conductivity. Dissipated ohmic energy is mostly conducted to the electrode wall. The higher thermal diffusivity of the wall versus the liquid, allows the ion source to run in steady state without heating.
Weak amenability of free products of hyperbolic and amenable groups
Authors: Vergara Ignacio
Published: January 2022

We show that if G is an amenable group and H is a hyperbolic group, then the free product
$G\ast H$
is weakly amenable. A key ingredient in the proof is the fact that
$G\ast H$
is orbit equivalent to
$\mathbb{Z}\ast H$
.
Social Movements and Social Policy: New Research Horizons
Authors: ISHKANIAN ARMINE
Published: January 2022

Across the globe, movements are confronting states and elites, challenging inequalities and mobilising for greater justice, a stronger voice, and progressive policy changes. In this article, I bridge the divide between Social Policy and the interdisciplinary field of Social Movement Studies. I examine how and why social movements, as actors in policy fields and social movement theories, matter for social policy. I argue that research on social movements as actors and engagement with social movement theories can open new horizons in Social Policy research by advancing our understanding of the politics of policy from a global perspective and strengthening our analytical and explanatory frameworks of agency, ideas, and power in the study of continuity and change of policy.
Contested disaster nationalism in the digital age: Emotional registers and geopolitical imaginaries in COVID-19 narratives on Chinese social media
Authors: Zhang Chenchen
Published: January 2022

This article examines how affective narratives of the COVID-19 pandemic on Chinese social media reinforce and challenge established scripts of national identity, political legitimacy, and international geopolitical imaginary. Taking theoretical insights from the scholarship on trauma, disaster nationalism, and politics of emotions, I structure the analysis of social media posts from state media and private accounts around three emotional registers: grief as a crucial site of control and contestation during the initial stage of the outbreak; gandong (being moved in a positive way) associated with stories of heroic sacrifices, national unity, and mundane ‘heart-warming’ moments; and enmity in narratives of power struggles and ideological competition between China and ‘the West’, especially the United States. While state media has sought to transform the crisis into resources for strengthening national belonging and regime legitimacy through a digital reworking of the long-standing repertoire of disaster nationalism, alternative articulations of grief, rage, and vernacular memory that refuse to be incorporated into the ‘correct collective memory’ of a nationalised tragedy have persisted in digital space. Furthermore, the article explicates the ways in which popular narratives affectively reinscribe dominant ideas about the (inter)national community: such as the historical imagination of a continuous nationhood rising from disasters and humiliation, positive energy, and a dichotomous view of the international order characterised by Western hegemony and Chinese victimhood. The geopolitical narratives of the pandemic build on and exacerbate binary oppositions between China and ‘the West’ in the global imaginary, which are co-constructed through discursive practices on both sides in mutually reinforcing ways. The lens of emotion allows us to attend to the resonances and dissonances between official and popular narrativisations of the disaster without assuming a one-way determinate relationship between the two.
PhD Abstracts
Authors: HUTTON GRAHAM
Published: January 2022

Many students complete PhDs in functional programming each year. As a service to the community, twice per year the Journal of Functional Programming publishes the abstracts from PhD dissertations completed during the previous year.

The abstracts are made freely available on the JFP website, i.e. not behind any paywall. They do not require any transfer of copyright, merely a license from the author. A dissertation is eligible for inclusion if parts of it have or could have appeared in JFP, that is, if it is in the general area of functional programming. The abstracts are not reviewed.

We are delighted to publish five abstracts in this round and hope that JFP readers will find many interesting dissertations in this collection that they may not otherwise have seen. If a student or advisor would like to submit a dissertation abstract for publication in this series, please contact the series editor for further details.

Graham Hutton

PhD Abstract Editor
Validating dietary assessment tools with energy expenditure measurement methods: Is this accurate?
Authors: Hejazi Jalal
Published: January 2022

Abstract. Having an accurate dietary assessment tool is a necessity for most nutritional studies. As a result, many validation studies have been carried out to assess the validity of commonly used dietary assessment tools. Since based on the energy balance equation, among individuals with a stable weight, Energy Intake (EI) is equal to Energy Expenditure (EE) and there are precise methods for measurement of EE (e.g. doubly labeled water method), numerous studies have used this technique for validating dietary assessment tools. If there was a discrepancy between measured EI and EE, the researchers have concluded that self-reported dietary assessment tools are not valid or participants misreport their dietary intakes. However, the calculation of EI with common dietary assessment tools such as food frequency questionnaires (FFQs), 24-hour dietary recalls, or weighed food records, is based on fixed factors that were introduced by Atwater and the accuracy of these factors are under question. Moreover, the amount of energy absorption, and utilization from a diet, depends on various factors and there are considerable interindividual differences in this regard, for example in gut microbiota composition. As a result, the EI which is calculated using dietary assessment tools is likely not representative of real metabolizable energy which is equal to EE in individuals with stable weight, thus validating dietary assessment tools with EE measurement methods may not be accurate. We aim to address this issue briefly and propose a feasible elucidation, albeit not a complete solution.
Natural Hazards Perspectives on Integrated, Coordinated, Open, Networked (ICON) Science
Authors: Sharma Sanjib , Dahal Kshitij , Nava Lorenzo , Gouli Manish Raj , Talchabhadel Rocky , Panthi Jeeban , Roy Tirthankar , Ghimire Ganesh R.
Published: January 2022

This article is about the state of ICON principles Goldman et al. (2021), https://doi.org/10.1029/2021EO153180 in natural hazards and a discussion on the opportunities and challenges of adopting them. Natural hazards pose risks to society, infrastructure, and the environment. Hazard interactions and their cascading phenomena in space and time can further intensify the impacts. Natural hazards’ risks are expected to increase in the future due to environmental, demographic, and socioeconomic changes. It is important to quantify and effectively communicate risks to inform the design and implementation of risk mitigation and adaptation strategies. Multihazard multisector risk management poses several nontrivial challenges, including: (a) integrated risk assessment, (b) Earth system data‐model fusion, (c) uncertainty quantification and communication, and (d) crossing traditional disciplinary boundaries. Here, we review these challenges, highlight current research and operational endeavors, and underscore diverse research opportunities. We emphasize the need for integrated approaches, coordinated processes, open science, and networked efforts (ICON) for multihazard multisector risk management.
Polycyclic Aromatic Hydrocarbons in China: Will Decoupling of Their Emissions and Socioeconomic Growth Emerge?
Authors: Cao Xianghui , Huo Shouliang , Zhang Hanxiao , Zhao Xiaoli , Guo Wei , He Zhuoshi , Ma Chunzi , Zheng Jiaqi , Song Shuai
Published: January 2022

Polycyclic aromatic hydrocarbons (PAHs) are emitted into the environment by daily anthropogenic activities and they potentially threaten human health. Over the past 40 years, the coupling between PAHs emissions driven by energy transition and socioeconomic factors has yet to be determined, and future trends between the two parameters are unclear. In China, the emissions of PAHs increased from 1980 to 2016, and the average annual variation rate was 3.5%. After 2016, PAHs emissions were decoupled from socioeconomic growth. PAHs emissions exhibited a change from a developed region (eastern region) to an undeveloped region (central region and western region). The emissions of PAHs, if only driven by energy transition, will reach a peak in 2035 under the shared economic pathways (SSP1, SSP2, SSP4, and SSP5), which are defined to assess sustainable development. The emissions of PAHs will continuously increase by +9.8% under SSP3 during 2020–2050. Comparing these five socioeconomic pathways, SSP1 is the possible choice to achieve the sustainable decoupling of the emissions of PAHs and socioeconomic growth by transforming the drivers of economic growth, thereby optimizing the energy system and cultivating environmentally friendly behaviors.