Flow coherent structures and frequency signature: Application of the dynamic modes decomposition to open cavity flow

International audienceThe dynamic dimension of an impinging flow may be significantly reduced by its boundary conditions and self-sustained oscillations they induce. The spectral signature is associated with remarkable spatial coherent structures. Dynamic modes decomposition (DMD) makes it possible to directly extract the dynamical properties of a non-linearly saturated flow. We apply DMD to highlight the spectral contribution of the longitudinal and transverse structures of an experimental open-cavity flow

Supplemental Iodide for Preterm Infants and Developmental Outcomes at 2 Years:an RCT

Background The recommendation for enteral iodide intake for preterm infants is 30–40 μg/kg/day and 1μg/kg/day for parenteral intake. Preterm infants are vulnerable to iodide insufficiency and thyroid dysfunction. The hypothesis tested whether, compared to placebo, iodide supplementation of preterm infants improves neurodevelopment. Methods A randomized controlled trial of iodide supplementation versus placebo in infants <31 weeks’ gestation. Trial solutions (sodium iodide or sodium chloride; dose 30μg/kg/day) were given within 42 hours of birth to the equivalent of 34 weeks’ gestation. The only exclusion criterion was maternal iodide exposure during pregnancy or delivery. Whole blood levels of thyroxine, thyrotropin and thyroid binding globulin were measured on four specific postnatal days. The primary outcome was neurodevelopmental status at two years’ of age, measured using the Bayley-III scales. The primary analyses are by intention-to-treat and data are presented also for survivors. Results 1,273 infants (637 intervention, 636 placebo) were recruited from 21 UK neonatal units. 131 infants died, and neurodevelopmental assessments were undertaken in 498 iodide and 499 placebo supplemented infants. There were no significant differences between the intervention and placebo groups in the primary outcome: mean difference Cognitive score, -0.34, 95% confidence interval (CI) -2.57 to 1.89; Motor composite score, 0.21, 95% CI -2.23 to 2.65; Language composite score, -0.05, 95%CI -2.48 to 2.39. There was evidence of weak interaction between iodide supplementation and hypothyroxinemic status in the Language composite score and one subtest score. Conclusions Overall iodide supplementation provided no benefit to neurodevelopment measured at 2 years of age

The role of the assessment policy in the relation between learning and performance

__Context:__ Optimising student learning and academic performance is a continuous challenge for medical schools. The assessment policy may influence both learning and performance. Previously, the joint contribution of self-regulated learning (SRL) and participation in scheduled learning activities towards academic performance has been reported. However, little is known about the relationships between SRL, participation and academic performance under different assessment policies. __Objectives:__ The goal of this study was to investigate differences in average scores of SRL, participation and academic performance of students under two assessment policies: (i) a conjunctive lower stakes, lower performance standard (old) assessment policy and (ii) a compensatory higher stakes, higher performance standard (new) assessment policy. In addition, this research investigated whether the relationships between academic performance, SRL and participation are similar across both assessment policies. __Methods:__ Year-1 medical students (i) under the old assessment policy (n = 648) and (ii) under the new assessment policy (n = 529) completed the Motivated Strategies for Learning Questionnaire on SRL, and additional items on participation. Year-1 performance was operationalised as students’ average Year-1 course examination grades. manova and structural equation modelling were used for analyses. __Results:__ Generally, students under the new assessment policy showed significantly higher Year-1 performance, SRL and participation, compared with students under the old assessment policy. The relationships between Year-1 performance, SRL and participation were similar across assessment policies. __Conclusions:__ This study indicates that the higher academic performance under a compensatory higher stakes, higher performance standard assessment policy, results from higher SRL and participation, but not from altered relationships between SRL, participation and performance. In sum, assessment policies have the potential to optimise student learning and performance

High critical currents for dendrite penetration and voiding in potassium metal anode solid-state batteries

Potassium metal anode solid-state cells with a K-beta”-alumina ceramic electrolyte are found to have relatively high critical currents for dendrite penetration on charge of approximately 4.8 mA/cm2, and voiding on discharge of approximately 2.0 mA/cm2, at 20 °C under 2.5 MPa stack-pressure. These values are higher than generally reported in the literature under comparable conditions for Li and Na metal anode solid-state batteries. The higher values for potassium are attributed to its lower yield strength and its readiness to creep under relatively low stack-pressures. The high critical currents of potassium anode solid-state batteries help to confirm the importance of the metal anode mechanical properties in the mechanisms of dendrite penetration and voiding.</p

Strain-controlled electrophysiological wave propagation alters in silico scar-based substrate for ventricular tachycardia

Introduction: Assessing a patient’s risk of scar-based ventricular tachycardia (VT) after myocardial infarction is a challenging task. It can take months to years after infarction for VT to occur. Also, if selected for ablation therapy, success rates are low. Methods: Computational ventricular models have been presented previously to support VT risk assessment and to provide ablation guidance. In this study, an extension to such virtual-heart models is proposed to phenomenologically incorporate tissue remodeling driven by mechanical load. Strain amplitudes in the heart muscle are obtained from simulations of mechanics and are used to adjust the electrical conductivity. Results: The mechanics-driven adaptation of electrophysiology resulted in a more heterogeneous distribution of propagation velocities than that of standard models, which adapt electrophysiology in the structural substrate from medical images only. Moreover, conduction slowing was not only present in such a structural substrate, but extended in the adjacent functional border zone with impaired mechanics. This enlarged the volumes with high repolarization time gradients (≥ 10 ms/mm). However, maximum gradient values were not significantly affected. The enlarged volumes were localized along the structural substrate border, which lengthened the line of conduction block. The prolonged reentry pathways together with conduction slowing in functional regions increased VT cycle time, such that VT was easier to induce, and the number of recommended ablation sites increased from 3 to 5 locations. Discussion: Sensitivity testing showed an accurate model of strain-dependency to be critical for low ranges of conductivity. The model extension with mechanics-driven tissue remodeling is a potential approach to capture the evolution of the functional substrate and may offer insight into the progression of VT risk over time.<br/

Moral decision-making and moral development: Toward an integrative framework

How moral decision-making occurs, matures over time and relates to behaviour is complex. To develop a full picture of moral decision-making, moral development and moral behaviour it is necessary to understand: (a) how real-time moral decisions are made (including relevant social and contextual factors), (b) what processes are required to develop to enable mature moral decisions, (c) how these processes develop over time, and (d) how moral decisions relate to behaviour. In this paper, psychological and social neuroscience theories of moral decision-making and development are briefly reviewed, as is the development of relevant component processes. Various component processes and factors are seen as required for moral decision-making and development, yet there is no comprehensive framework incorporating these components into one explanation of how real-time moral decisions are made and mature. In this paper, we integrated these components into a new framework based on social information processing (SIP) theory. Situational factors, and how both cognitive and affective process guide moral decisions was incorporated into the Social Information Processing-Moral Decision-Making (SIP-MDM) framework, drawing upon theories and findings from developmental psychology and social neuroscience. How this framework goes beyond previous SIP models was outlined, followed by a discussion of how it can explai

Capnocytophaga ochracea Septicemia

A case report describing Capnocytophaga ochracea (Bacteroides ochraceus) septicemia in a 21-year-old male patient receiving chemotherapy for acute lymphocytic leukemia is presented. The unusual features of this organism are discussed together with a review of the literature

Observational signatures of a non-singular bouncing cosmology

We study a cosmological scenario in which inflation is preceded by a bounce. In this scenario, the primordial singularity, one of the major shortcomings of inflation, is replaced by a non-singular bounce, prior to which the universe undergoes a phase of contraction. Our starting point is the bouncing cosmology investigated in Falciano et al. (2008), which we complete by a detailed study of the transfer of cosmological perturbations through the bounce and a discussion of possible observational effects of bouncing cosmologies. We focus on a symmetric bounce and compute the evolution of cosmological perturbations during the contracting, bouncing and inflationary phases. We derive an expression for the Mukhanov-Sasaki perturbation variable at the onset of the inflationary phase that follows the bounce. Rather than being in the Bunch-Davies vacuum, it is found to be in an excited state that depends on the time scale of the bounce. We then show that this induces oscillations superimposed on the nearly scale-invariant primordial spectra for scalar and tensor perturbations. We discuss the effects of these oscillations in the cosmic microwave background and in the matter power spectrum. We propose a new way to indirectly measure the spatial curvature energy density parameter in the context of this model.Comment: 40 pages, 5 figures, typos corrected and reference adde

Identification and quantification of <i>Acanthamoeba</i> spp. within seawater at four coastal lagoons on the east coast of Australia

Acanthamoeba is an opportunistic free-living heterotrophic protist that is the most predominant amoeba in diverse ecological habitats. Acanthamoeba causes amoebic keratitis (AK), a painful and potentially blinding corneal infection. Major risk factors for AK have been linked to non-optimal contact lens hygiene practices and Acanthamoeba contamination of domestic and recreational water. This study investigated the incidence and seasonal variation of Acanthamoeba spp. within coastal lagoons located on the eastern coast of Australia and then examined the association between Acanthamoeba and water abiotic factors and bacterial species within the water.Water samples were collected from four intermittently closed and open lagoons (ICOLLs) (Wamberal, Terrigal, Avoca and Cockrone) every month between August 2019 to July 2020 except March and April. qPCR was used to target the Acanthamoeba 18S rRNA gene, validated by Sanger sequencing. Water abiotic factors were measured in situ using a multiprobe metre and 16S rRNA sequencing (V3-V4) was performed to characterise bacterial community composition. Network analysis was used to gauge putative associations between Acanthamoeba incidence and bacterial amplicon sequence variants (ASVs).Among 206 water samples analysed, 79 (38.3%) were Acanthamoeba positive and Acanthamoeba level was significantly higher in summer compared with winter, spring, or autumn (p = 0.008). More than 50% (23/45) water samples of Terrigal were positive for Acanthamoeba which is a highly urbanised area with extensive recreational activities while about 32% (16/49) samples were positive from Cockrone that is the least impacted lagoon by urban development. All sequenced strains belonged to the pathogenic genotype T4 clade except two which were of genotype clades T2 and T5. Water turbidity, temperature, intl1 gene concentration, and dissolved O2 were significantly associated with Acanthamoeba incidence (p &lt; 0.05). The ASVs level of cyanobacteria, Pseudomonas spp., Candidatus spp., and marine bacteria of the Actinobacteria phylum and Acanthamoeba 18S rRNA genes were positively correlated (Pearson's r ≥ 0.14). The presence of Acanthamoeba spp. in all lagoons, except Wamberal, was associated with significant differences in the composition of bacterial communities (beta diversity).The results of this study suggest that coastal lagoons, particularly those in urbanised regions with extensive water recreational activities, may pose an elevated risk to human health due to the relatively high incidence of pathogenic Acanthamoeba in the summer. These findings underscore the importance of educating the public about the rare yet devastating impact of AK on vision and quality of life, highlighting the need for collaborative efforts between public health officials and educators to promote awareness and preventive measures, especially focusing lagoons residents and travellers