Order-of-magnitude speedup for steady states and traveling waves via Stokes preconditioning in Channelflow and Openpipeflow

Steady states and traveling waves play a fundamental role in understanding hydrodynamic problems. Even when unstable, these states provide the bifurcation-theoretic explanation for the origin of the observed states. In turbulent wall-bounded shear flows, these states have been hypothesized to be saddle points organizing the trajectories within a chaotic attractor. These states must be computed with Newton's method or one of its generalizations, since time-integration cannot converge to unstable equilibria. The bottleneck is the solution of linear systems involving the Jacobian of the Navier-Stokes or Boussinesq equations. Originally such computations were carried out by constructing and directly inverting the Jacobian, but this is unfeasible for the matrices arising from three-dimensional hydrodynamic configurations in large domains. A popular method is to seek states that are invariant under numerical time integration. Surprisingly, equilibria may also be found by seeking flows that are invariant under a single very large Backwards-Euler Forwards-Euler timestep. We show that this method, called Stokes preconditioning, is 10 to 50 times faster at computing steady states in plane Couette flow and traveling waves in pipe flow. Moreover, it can be carried out using Channelflow (by Gibson) and Openpipeflow (by Willis) without any changes to these popular spectral codes. We explain the convergence rate as a function of the integration period and Reynolds number by computing the full spectra of the operators corresponding to the Jacobians of both methods.Comment: in Computational Modelling of Bifurcations and Instabilities in Fluid Dynamics, ed. Alexander Gelfgat (Springer, 2018

Atlantic Cod Piscidin and Its Diversification through Positive Selection

Piscidins constitute a family of cationic antimicrobial peptides that are thought to play an important role in the innate immune response of teleosts. On the one hand they show a remarkable diversity, which indicates that they are shaped by positive selection, but on the other hand they are ancient and have specific targets, suggesting that they are constrained by purifying selection. Until now piscidins had only been found in fish species from the superorder Acanthopterygii but we have recently identified a piscidin gene in Atlantic cod (Gadus morhua), thus showing that these antimicrobial peptides are not restricted to evolutionarily modern teleosts. Nucleotide diversity was much higher in the regions of the piscidin gene that code for the mature peptide and its pro domain than in the signal peptide. Maximum likelihood analyses with different evolution models revealed that the piscidin gene is under positive selection. Charge or hydrophobicity-changing amino acid substitutions observed in positively selected sites within the mature peptide influence its amphipathic structure and can have a marked effect on its function. This diversification might be associated with adaptation to new habitats or rapidly evolving pathogens

Impact of Physician Personality Traits on Drug PrescriptionBehaviour

Purpose: Our research investigated how physicians’ personality traits influence and interplay with other factors guiding their prescribing and medical decisions in a branded generics market like India.Design/methodology/approach:Our research is based on a conceptual framework andsurvey questionnaire developed from an extensive literature review on independent variables. Along with the other independent variables like Physician’s professional factors, Product-related factors, and product promotion factors, for physician’s personality traits as a factor, the survey questionnaire was integrated with HOGAN’s MVPI Questions, which were exposed to 171 respiratory physiciansfor recording their responses. Statistical methods or tools like descriptive personality, and inferentialstatistics from the latest SPSS 21 version have been employedFindings: Our findings showed that respiratory physician’s product prescribing decisions were significantly influenced by their specific personality traits such as Altruistic traits, Security traits, and Commerce traits apart from other factors such as Physician’s professional and pharmaceuticalProduct-related factors.Practical implications: The findings highlight the critical necessity for a thorough recording of physicians\u27 prescribing practices, which are significantly influenced by their distinct personality traits. Healthcare authorities must prioritize the regular assessment of physicians\u27 psychological well-being and overall health. This proactive approach enables physicians to promptly address any health issues in cases of burnout, thereby ensuring the continuous delivery of high-quality patient care. With the government making it, mandatory for all pharmaceutical organizations to follow the uniform product promotion code (UPPC) while promoting products to physicians, marketers need to strategically allocate optimal resources and outreach efforts with tailor-made marketing mix elements that are aligned with the preferences and personality traits of physicians, aimed towards enhancing their clinical knowledge, followed by the development of continuous patient initiatives aiming to improve their awareness, can lead to the development of belief with two-way communication among them leading to better treatment adherence and compliance from patients end. Such dedicated efforts initiated by the marketers, in the long term cancultivate trust and empathy between physicians and patients, laying the robust groundwork for patient-centered disease management. This can enable the development of goodwill or a better perception of pharmaceutical organizational promotional efforts by physicians, which is one of the aims of getting physician’s prescriptions for the promoted product

Epidemiology of Pediatric Chronic Pain: An Overview of Systematic Reviews

Purpose of Review: Chronic non-cancer pain in children and adolescents represents a significant public health issue, affecting physical, psychological, and social well-being. Defined as pain persisting for over three months, this condition is influenced by developmental, socioeconomic, and cultural factors. However, its prevalence remains uncertain and debated. A comprehensive literature search was conducted across electronic databases, including Medline, Embase, CINAHL, PsycINFO, and the Cochrane Library. Eligible systematic reviews were critically appraised using the AMSTAR-2 tool to assess methodological quality. This overview synthesises evidence from existing systematic reviews to provide an updated understanding of the epidemiology and burden of paediatric non-cancer chronic pain. Recent Findings: Findings revealed substantial variability in the reported prevalence of specific pain types: headaches (4–83%), abdominal pain (4–53%), musculoskeletal pain (4–40%), and back/low-back pain (14–24%). Prevalence was generally lower in low- and middle-income countries, likely due to barriers in healthcare access. Methodological heterogeneity was observed across studies, and AMSTAR-2 assessment identified critical limitations in some systematic reviews, impacting the reliability of findings. Summary: This overview highlights the urgent need for standardised research methodologies to accurately monitor the prevalence of paediatric non-cancer chronic pain. Standardisation is essential for informing policies aimed at mitigating the long-term impact of chronic pain in children and adolescents. Addressing these issues, particularly in resource-limited settings, is crucial for improving health outcomes and reducing societal and economic burdens

Successful Spinal Cord Stimulation for Necrotizing Raynaud's Phenomenon in COVID-19 Affected Patient: The Nightmare Comes Back

Necrotizing Raynaud's phenomenon is a vascular clinical syndrome characterized by vasospasm of distal resistance vessels, usually triggered by cold temperatures or by psychological conditions such as anxiety and stress. Pain is the first reported symptom, related to insufficient oxygen delivery to the extremities that leads to ischemia of the peripheral tissues. The initial treatment is conservative, but if the symptoms persist, necrosis and distal amputation can occur. In selected patients, neuromodulation with spinal cord stimulation (SCS) can be an effective treatment by reducing pain and amputation rate. Recent evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause endotheliopathy with microvascular and macrovascular thrombotic events and can present as a systemic inflammatory vascular disease.We present a case of a severe necrotizing Raynaud's phenomenon successfully treated and controlled with SCS that abruptly reappeared during SARS-CoV-2 infection.The report of this case is suggestive for potential treatment in case of peripheral ischemia consequent to COVID-19 vasculopathy. The interaction between SCS and SARS-CoV-2-related endotheliopathy is unknown and would deserve further studies

Opioids in the Elderly Patients with Cognitive Impairment: A Narrative Review

Introduction Assessment and management of pain in elderly people with cognitive impairment is particularly challenging. Physiological changes due to aging as well as comorbidities and polypharmacy are responsible for a complex clinical approach. Concomitantly, in cognitive impairment, including advanced dementia, changes in the central nervous system along with changes in the peripheral nervous system due to aging have a significant impact on pain perception. Sometimes clinicians decide to prescribe opioids to relieve pain, also without a clear indication. This review aims to investigate the effect of opioids in elderly patients with cognitive impairment. Methods A literature search of PubMed/Medline, Scopus, and Cochrane databases was conducted using keyword searches to generate lists of articles that were screened for relevance by title and abstract to give a final list of articles for full-text review. Further articles were identified by scanning the reference lists of the full-text articles. Discussion This review discusses the complex physiological and pharmacological changes in the elderly as well as the neurological changes that affect pain perception in this population. Additionally, it focuses on cognitive impairment and pain in Alzheimer's disease and other dementias, the pain assessment in the elderly with cognitive impairment as well as the safety of opioid use in the elderly. Information regarding opioid prescription in nursing homes and recorded indications for opioid use, type and dosing of opioids, and compliance of treatment in advanced dementia are also provided. Conclusions Opioid prescription in the elderly population with cognitive impairment is particularly complex. All healthcare professionals involved in the care of such patients need to be aware of the challenges and strive to ensure analgesic use is guided by appropriate and accurate pain assessment

Do dividends signal future earnings in the Nordic stock markets?

We study the informational content of dividends on three Nordic civil law markets, where other simultaneous but blurring motives for dividends may be weaker. Using aggregate data on real earnings per share and payout ratios, long time series from 1969 to 2010, and methodologies which address problems of endogeneity, non-stationarity and autocorrelation (including a Vector Error Correction Model approach), we find evidence on dividend signaling in Nordic markets. However, we also find heterogeneity in the relationship between dividends and earnings on markets similar in many respects, suggesting that even small variations in the institutional surroundings may be important for the results

Oxygen uptake kinetics in trained adolescent females

Little evidence exists with regard to the effect that exercise training has upon oxygen uptake kinetics in adolescent females. PURPOSE: The aim of the study was to compare [Formula: see text] and muscle deoxygenation kinetics in a group of trained (Tr) and untrained (Utr) female adolescents. METHOD: Twelve trained (6.4 ± 0.9 years training, 10.3 ± 1.4 months per year training, 5.2 ± 2.0 h per week) adolescent female soccer players (age 14.6 ± 0.7 years) were compared to a group (n = 8) of recreationally active adolescent girls (age 15.1 ± 0.6 years) of similar maturity status. Subjects underwent two, 6-min exercise transitions at a workload equivalent to 80 % of lactate threshold from a 3-min baseline of 10 W. All subjects had a passive rest period of 1 h between each square-wave transition. Breath-by-breath oxygen uptake and muscle deoxygenation were measured throughout and were modelled via a mono-exponential decay with a delay relative to the start of exercise. RESULT: Peak [Formula: see text] was significantly (p < 0.05) greater in the Tr compared to the Utr (Tr: 43.2 ± 3.2 mL kg(-1 )min(-1) vs. Utr: 34.6 ± 4.0 mL kg(-1 )min(-1)). The [Formula: see text] time constant was significantly (p < 0.05) faster in the Tr compared to the Utr (Tr: 26.3 ± 6.9 s vs. Utr: 35.1 ± 11.5 s). There was no inter-group difference in the time constant for muscle deoxygenation kinetics (Tr: 8.5 ± 3.0 s vs. Utr: 12.4 ± 8.3 s); a large effect size, however, was demonstrated (-0.804). CONCLUSION: Exercise training and/or genetic self-selection results in faster kinetics in trained adolescent females. The faster [Formula: see text] kinetics seen in the trained group may result from enhanced muscle oxygen utilisation

The use of positive end expiratory pressure in patients affected by COVID-19: Time to reconsider the relation between morphology and physiology

Coronavirus disease 2019 (COVID-19) is a new disease with different phases that can be catastrophic for subpopulations of patients with cardiovascular and pulmonary disease states at baseline. Appreciation for these different phases and treatment modalities, including manipulation of ventilatory settings and therapeutics, has made it a less lethal disease than when it emerged earlier this year. Different aspects of the disease are still largely unknown. However, laboratory investigation and clinical course of the COVID-19 show that this new disease is not a typical acute respiratory distress syndrome process, especially during the first phase. For this reason, the best strategy to be applied is to treat differently the single phases and to support the single functions of the failing organs as they appear